Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
FLEXIBLE ROTATIONALLY MOLDED ARTICLE
FIELD OF THE DISCLOSURE
This disclosure relates the use of ethylene interpolymer products having a
melt index of from 2.5 to 8.0 g/10 minutes, a density of from 0.905 to 0.920
g/cm3
and a Dilution Index, Yd, of greater than 0 degrees to prepare flexible
rotationally
molded articles.
BACKGROUND OF THE DISCLOSURE
The preparation of ethylene interpolymer products having a dilution index, Yd,
of greater than 0 degrees is disclosed in U.S. Pat. Nos 10,035,906 and
9,512,282.
The preparation of rotomolded articles from medium density ethylene
interpolymer products having a dilution index, Yd, of greater than 0 degrees
is
disclosed in U.S. Pat. Nos 10,023,706 and 10,040,928.
U.S. Pat. Pub. No. 2018/0298170 claims ethylene interpolymer products
having a density of from 0.910 to 0.912 g/cm3 and a dilution index, Yd, of
greater
than 0 degrees.
SUMMARY OF THE DISCLOSURE
We now report the preparation of flexible rotationally molded articles from
low
density ethylene interpolymer products having a dilution index, Yd, of greater
than 0
degrees.
The low density ethylene interpolymer products having a dilution index, Yd, of
greater than 0 degrees can be used to make rotomolded articles that are
flexible,
with a "soft touch" or "soft touch feel".
An embodiment of the disclosure is a rotomolded article prepared from an
ethylene interpolymer product having a melt index, 12 of from 2.5 to 8.0
g/10min, and
a density of from 0.905 to 0.920 g/cm3; wherein said ethylene interpolymer
product
comprises:
(1) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(P1)b(Q)n
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wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; and Q is independently selected from the group consisting of a
hydrogen
atom, a halogen atom, a Ci_io hydrocarbyl radical, a Ci-io alkoxy radical and
a C5-10
aryl oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals
may be unsubstituted or further substituted by a halogen atom, a C1-18 alkyl
radical, a
C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals or a phosphido
radical
which is unsubstituted or substituted by up to two C1-8 alkyl radicals;
wherein a is 1; b
is 1; n is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M,
and;
wherein said second ethylene interpolymer is produced using a first Ziegler-
Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first Ziegler-Natta catalyst formulation or a second Ziegler-Natta
catalyst
formulation, and;
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0.
An embodiment of the disclosure is a flexible or "soft touch feel" rotomolded
article prepared from an ethylene interpolymer product having a melt index, 12
of from
2.5 to 8.0 g/10min, and a density of from 0.905 to 0.920 g/cm3; wherein said
ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(PN(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; and Q is independently selected from the group consisting of a
hydrogen
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atom, a halogen atom, a Ci-io hydrocarbyl radical, a Ci-io alkoxy radical and
a C5-10
aryl oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals
may be unsubstituted or further substituted by a halogen atom, a C1-18 alkyl
radical, a
C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals or a phosphido
radical
which is unsubstituted or substituted by up to two C1-8 alkyl radicals;
wherein a is 1; b
is 1; n is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M,
and;
wherein said second ethylene interpolymer is produced using a first Ziegler-
Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first Ziegler-Natta catalyst formulation or a second Ziegler-Natta
catalyst
formulation, and;
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0.
An embodiment of the disclosure is rotomolded article prepared from an
ethylene interpolymer product having a melt index of from about 2.5 to 8.0
dg/minute, wherein melt index is measured according to ASTM D 1238 (2.16 kg
load
and 190 C) and a density of from 0.905 to 0.920 g/cm3, wherein density is
measured
according to ASTM D792; wherein said ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(III) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(PI)b(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; Q is independently selected from the group consisting of a hydrogen
atom, a
halogen atom, a Ci-io hydrocarbyl radical, a Ci-io alkoxy radical and a C5-10
aryl
oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals may
be unsubstituted or further substituted by a halogen atom, a C1-18 alkyl
radical, a C1-8
alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which is
unsubstituted
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or substituted by up to two C1-8 alkyl radicals or a phosphido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals; wherein a is 1;
b is 1; n
is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M;
wherein said second ethylene interpolymer is produced using a first in-line
Ziegler-Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first in-line Ziegler-Natta catalyst formulation or a second in-line
Ziegler-Natta
catalyst formulation; and,
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0.
An embodiment of the disclosure is a flexible or "soft touch feel" rotomolded
article prepared from an ethylene interpolymer product having a melt index of
from
about 2.5 to 8.0 dg/minute, wherein melt index is measured according to ASTM D
1238 (2.16 kg load and 190 C) and a density of from 0.905 to 0.920 g/cm3,
wherein
density is measured according to ASTM 0792; wherein said ethylene interpolymer
product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(III) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(PI)b(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; Q is independently selected from the group consisting of a hydrogen
atom, a
halogen atom, a Ci-io hydrocarbyl radical, a C1-10 alkoxy radical and a C5-10
aryl
oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals may
be unsubstituted or further substituted by a halogen atom, a C1-16 alkyl
radical, a C1-8
alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which is
unsubstituted
or substituted by up to two C1-8 alkyl radicals or a phosphido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals; wherein a is 1;
b is 1; n
is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M;
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wherein said second ethylene interpolymer is produced using a first in-line
Ziegler-Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first in-line Ziegler-Natta catalyst formulation or a second in-line
Ziegler-Natta
catalyst formulation; and,
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0.
An embodiment of the disclosure is a process for forming a rotomolded article,
the process comprising:
(a) preparing an ethylene interpolymer product having a melt index, 12 of from
2.5 to 8.0 g/10min, and a density of from 0.905 to 0.920 g/cm3; wherein said
ethylene interpolymer product comprises:
(1) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(P1)b(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; and Q is independently selected from the group consisting of a
hydrogen
atom, a halogen atom, a Ci_io hydrocarbyl radical, a Ci_io alkoxy radical and
a C5-10
.. aryl oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl
oxide radicals
may be unsubstituted or further substituted by a halogen atom, a C1-18 alkyl
radical, a
C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals or a phosphido
radical
which is unsubstituted or substituted by up to two C1-8 alkyl radicals;
wherein a is 1; b
.. is 1; n is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M;
wherein said second ethylene interpolymer is produced using a first Ziegler-
Natta catalyst formulation;
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wherein said third ethylene interpolymer, when present, is produced using
said first Ziegler-Natta catalyst formulation or a second Ziegler-Natta
catalyst
formulation; and,
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0; and
(b) rotomolding the ethylene interpolymer product to form a rotomolded
article.
An embodiment of the disclosure is a rotomolded article prepared from an
ethylene interpolymer product having a melt index, 12 of from 2.5 to 8.0
g/10min, and
a density of from 0.905 to 0.920 g/cm3; wherein said ethylene interpolymer
product
comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said ethylene interpolymer product has a Dilution Index, Yd, of from
4.5 to 6.5.
An embodiment of the disclosure is a flexible or "soft touch feel" rotomolded
article prepared from an ethylene interpolymer product having a melt index, 12
of from
2.5 to 8.0 g/10min, and a density of from 0.905 to 0.920 g/cm3; wherein said
ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said ethylene interpolymer product has a Dilution Index, Yd, of from
4.5 to 6.5.
BRIEF DESCRIPTION OF THE FIGURES
Figure IA shows the gel permeation chromatograph (GPC) with refractive
index detection of ethylene interpolymer products made according to the
present
disclosure.
Figure 1B shows the deconvolution of Example Al. The experimentally
measured GPC chromatogram was deconvoluted into a first and a second ethylene
interpolymer.
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Figure 2 shows the gel permeation chromatograph (GPC) with refractive index
detection of an ethylene interpolymer product made according to the present
disclosure as well as for various comparative resins.
Figure 3 shows the gel permeation chromatograph with Fourier transform
infra-red (GPC-FTIR) detection obtained for ethylene interpolymer products
made
according to the present disclosure. The comonomer content, shown as the
number
of short chain branches per 1000 backbone carbons (y-axis), is given relative
to the
copolymer molecular weight (x-axis). The relatively flat line (from left to
right) is the
short chain branching (in short chain branches per 1000 carbons atoms)
determined
by FTIR. As can be seen in Figure 3, for Examples Al and 1, the number of
short
chain branches is relatively constant with molecular weight, and hence the
comonomer incorporation is said to be "flat" or "uniform".
Figure 4 shows the gel permeation chromatograph with Fourier transform
infra-red (GPC-FTIR) detection obtained for an ethylene interpolymer product
made
according to the present disclosure as well as for various comparative resins.
The
comonomer content, shown as the number of short chain branches per 1000
backbone carbons (y-axis), is given relative to the copolymer molecular weight
(x-
axis). As can be seen in Figure 4, for Example 1, the number of short chain
branches is relatively constant with molecular weight, and hence the comonomer
incorporation is said to be "flat" or "uniform".
Figure 5 shows the differential scanning calorimetry final heating curve for
an
ethylene interpolymer product made according to the present disclosure as well
as
for various comparative resins.
Figure 6 shows the viscosity profiles from a DMA frequency sweep carried out
at 190 C for an ethylene interpolymer product made according to the present
disclosure as well as for various comparative resins.
DETAILED DESCRIPTION
Definition of Terms
Other than in the examples or where otherwise indicated, all numbers or
expressions referring to quantities of ingredients, extrusion conditions,
etc., used in
the specification and claims are to be understood as modified in all instances
by the
term "about." Accordingly, unless indicated to the contrary, the numerical
parameters set forth in the following specification and attached claims are
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approximations that can vary depending upon the desired properties that the
various
embodiments desire to obtain. At the very least, and not as an attempt to
limit the
application of the doctrine of equivalents to the scope of the claims, each
numerical
parameter should at least be construed in light of the number of reported
significant
digits and by applying ordinary rounding techniques. The numerical values set
forth
in the specific examples are reported as precisely as possible. Any numerical
values, however, inherently contain certain errors necessarily resulting from
the
standard deviation found in their respective testing measurements.
It should be understood that any numerical range recited herein is intended to
include all sub-ranges subsumed therein. For example, a range of "1 to 10" is
intended to include all sub-ranges between and including the recited minimum
value
of 1 and the recited maximum value of 10; that is, having a minimum value
equal to
or greater than 1 and a maximum value of equal to or less than 10. Because the
disclosed numerical ranges are continuous, they include every value between
the
minimum and maximum values. Unless expressly indicated otherwise, the various
numerical ranges specified in this application are approximations.
All compositional ranges expressed herein are limited in total to and do not
exceed 100 percent (volume percent or weight percent) in practice. Where
multiple
components can be present in a composition, the sum of the maximum amounts of
each component can exceed 100 percent, with the understanding that, and as
those
skilled in the art readily understand, that the amounts of the components
actually
used will conform to the maximum of 100 percent.
In order to form a more complete understanding of this disclosure the
following terms are defined and should be used with the accompanying figures
and
the description of the various embodiments throughout.
The term "Dilution Index (Yd)", which has dimensions of degrees ( ), and the
"Dimensionless Modulus (Xd)" are based on rheological measurements and are
fully
described in this disclosure.
As used herein, the term "monomer" refers to a small molecule that may
chemically react and become chemically bonded with itself or other monomers to
form a polymer.
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As used herein, the term "a-olefin" is used to describe a monomer having a
linear hydrocarbon chain containing from 3 to 20 carbon atoms having a double
bond
at one end of the chain.
As used herein, the term "ethylene polymer", refers to macromolecules
produced from ethylene monomers and optionally one or more additional
monomers;
regardless of the specific catalyst or specific process used to make the
ethylene
polymer. In the polyethylene art, the one or more additional monomers are
called
"comonomer(s)" and often include a-olefins. The term "homopolymer" refers to a
polymer that contains only one type of monomer. Common ethylene polymers
include high density polyethylene (HDPE), medium density polyethylene (MDPE),
linear low density polyethylene (LLDPE), very low density polyethylene
(VLDPE),
ultralow density polyethylene (ULDPE), plastomer and elastomers. The term
ethylene polymer also includes polymers produced in a high pressure
polymerization
processes; non-limiting examples include low density polyethylene (LDPE),
ethylene
vinyl acetate copolymers (EVA), ethylene alkyl acrylate copolymers, ethylene
acrylic
acid copolymers and metal salts of ethylene acrylic acid (commonly referred to
as
ionomers). The term ethylene polymer also includes block copolymers which may
include 2 to 4 comonomers. The term ethylene polymer also includes
combinations
of, or blends of, the ethylene polymers described above.
The term "ethylene interpolymer" refers to a subset of polymers within the
"ethylene polymer" group that excludes polymers produced in high pressure
polymerization processes; non-limiting examples of polymers produced in high
pressure processes include LDPE and EVA (the latter is a copolymer of ethylene
and vinyl acetate).
The term "heterogeneous ethylene interpolymers" refers to a subset of
polymers in the ethylene interpolymer group that are produced using a
heterogeneous catalyst formulation; non-limiting examples of which include
Ziegler-
Natta or chromium catalysts.
The term "homogeneous ethylene interpolymer" refers to a subset of polymers
in the ethylene interpolymer group that are produced using metallocene or
single-site
catalysts. Typically, homogeneous ethylene interpolymers have narrow molecular
weight distributions, for example gel permeation chromatography (GPC) Mw/Mn
values of less than 2.8; Mw and Mn refer to weight and number average
molecular
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weights, respectively. In contrast, the Mw/Mn of heterogeneous ethylene
interpolymers are typically greater than the Mw/Mn of homogeneous ethylene
interpolymers. In general, homogeneous ethylene interpolymers also have a
narrow
comonomer distribution, i.e. each macromolecule within the molecular weight
distribution has a similar comonomer content. Frequently, the composition
distribution breadth index "CDBI" is used to quantify how the comonomer is
distributed within an ethylene interpolymer, as well as to differentiate
ethylene
interpolymers produced with different catalysts or processes. The "CDBI50" is
defined as the percent of ethylene interpolymer whose composition is within
50% of
the median comonomer composition; this definition is consistent with that
described
in U.S. Patent 5,206,075 assigned to Exxon Chemical Patents Inc. The CDBI50 of
an
ethylene interpolymer can be calculated from TREF curves (Temperature Rising
Elution Fractionation); the TREF method is described in Wild, et al., J.
Polym. Sci.,
Part B, Polym. Phys., Vol. 20 (3), pages 441-455. Typically the CDBI50 of
homogeneous ethylene interpolymers are greater than about 70%. In contrast,
the
CDBI50 of a-olefin containing heterogeneous ethylene interpolymers are
generally
lower than the CDBI50 of homogeneous ethylene interpolymers.
It is well known to those skilled in the art, that homogeneous ethylene
interpolymers are frequently further subdivided into "linear homogeneous
ethylene
interpolymers" and "substantially linear homogeneous ethylene interpolymers".
These two subgroups differ in the amount of long chain branching.: more
specifically,
linear homogeneous ethylene interpolymers have less than about 0.01 long chain
branches per 1000 carbon atoms; while substantially linear ethylene
interpolymers
have greater than about 0.01 to about 3.0 long chain branches per 1000 carbon
atoms. A long chain branch is macromolecular in nature, i.e. similar in length
to the
macromolecule that the long chain branch is attached to. Hereafter, in this
disclosure, the term "homogeneous ethylene interpolymer" refers to both linear
homogeneous ethylene interpolymers and substantially linear homogeneous
ethylene interpolymers.
Herein, the term "polyolefin" includes ethylene polymers and propylene
polymers; non-limiting examples of propylene polymers include isotactic,
syndiotactic
and atactic propylene homopolymers, random propylene copolymers containing at
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least one comonomer and impact polypropylene copolymers or heterophasic
polypropylene copolymers.
The term "thermoplastic" refers to a polymer that becomes liquid when
heated, will flow under pressure and solidify when cooled. Thermoplastic
polymers
include ethylene polymers as well as other polymers commonly used in the
plastic
industry; non-limiting examples of other polymers commonly used in film
applications
include barrier resins (EVOH), tie resins, polyethylene terephthalate (PET),
polyamides and the like.
As used herein, the terms "hydrocarbyl", "hydrocarbyl radical" or "hydrocarbyl
group" refers to linear or cyclic, aliphatic, olefinic, acetylenic and aryl
(aromatic)
radicals comprising hydrogen and carbon that are deficient by one hydrogen.
As used herein, an "alkyl radical" includes linear, branched and cyclic
paraffin
radicals that are deficient by one hydrogen radical; non-limiting examples
include
methyl (-CH3) and ethyl (-CH2CH3) radicals. The term "alkenyl radical" refers
to
linear, branched and cyclic hydrocarbons containing at least one carbon-carbon
double bond that is deficient by one hydrogen radical.
Herein the term "R1" and its superscript form "Rl" refers to a first reactor
in a
continuous solution polymerization process; it being understood that R1 is
distinctly
different from the symbol R1; the latter is used in chemical formula, e.g.
representing
a hydrocarbyl group. Similarly, the term "R2" and its superscript form "R2"
refers to a
second reactor, and; the term "R3" and its superscript form "R3" refers to a
third
reactor.
As used herein the term "unsubstituted" means that hydrogen radicals are
bounded to the molecular group that follows the term unsubstituted. The term
"substituted" means that the group following this term possesses one or more
moieties (non hydrogen radicals) that have replaced one or more hydrogen
radicals
in any position within the group; non-limiting examples of moieties include
halogen
radicals (F, Cl, Br), hydroxyl groups, carbonyl groups, carboxyl groups, silyl
groups,
amine groups, phosphine groups, alkoxy groups, phenyl groups, naphthyl groups,
Ci
to C30 alkyl groups, C2 to C30 alkenyl groups, and combinations thereof. Non-
limiting
examples of substituted alkyls and aryls include: acyl radicals, alkyl silyl
radicals,
alkylamino radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals,
dialkylamino
radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl
radicals, alkyl-
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and dialkyl-carbamoyl radicals, acyloxy radicals, acylamino radicals,
arylamino
radicals and combinations thereof.
Catalysts
Organometallic catalyst formulations that are efficient in polymerizing
olefins
are well known in the art. In embodiments disclosed herein, at least two
catalyst
formulations are employed in a continuous solution polymerization process. One
of
the catalyst formulations is a single-site catalyst formulation that produces
a first
ethylene interpolymer. The other catalyst formulation is a heterogeneous
catalyst
formulation that produces a second ethylene interpolymer. Optionally a third
ethylene interpolymer is produced using the heterogeneous catalyst formulation
that
was used to produce the second ethylene interpolymer, or a different
heterogeneous
catalyst formulation may be used to produce the third ethylene interpolymer.
In the
continuous solution process, the first ethylene interpolymer (i.e. at least
one
homogeneous ethylene interpolymer), the second ethylene interpolymer (i.e. at
least
one heterogeneous ethylene interpolymer), and optionally a third ethylene
interpolymer (i.e. an optional heterogeneous ethylene interpolymer) are
solution
blended and an ethylene interpolymer product is produced.
Single Site Catalyst Formulation
The catalyst components which make up the single site catalyst formulation
are not particularly limited, i.e. a wide variety of catalyst components can
be used.
One non-limiting embodiment of a single site catalyst formulation comprises
the
following three or four components: a bulky ligand-metal complex; an alumoxane
co-
catalyst; an ionic activator and optionally a hindered phenol. In Table 1 of
this
disclosure: "(i)" refers to the amount of "component (i)", i.e. the bulky
ligand-metal
complex added to R1; "(ii)" refers to "component (ii)", i.e. the alumoxane co-
catalyst;
"(iii)" refers to "component (iii)" i.e. the ionic activator, and; "(iv)"
refers to "component
(iv)", i.e. the optional hindered phenol.
Non-limiting examples of component (i) are represented by formula (I):
(LA)aM(P0b(Q)n (I)
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wherein (LA) represents a bulky ligand; M represents a metal atom; PI
represents a
phosphinimine ligand; Q represents a leaving group; a is 0 or 1; b is 1 or 2;
(a+b) =
2; n is 1 or 2, and; the sum of (a+b+n) equals the valance of the metal M.
In an embodiment of the disclosure, LA is selected from the group consisting
of unsubstituted cyclopentadienyl, substituted cyclopentadienyl, unsubstituted
indenyl, substituted indenyl, unsubstituted fluorenyl and substituted
fluorenyl.
In an embodiment of the disclosure, M is a metal selected from the group
consisting of titanium, hafnium and zirconium
In further non-limiting embodiments of the disclosure, the bulky ligand LA in
formula (I) includes unsubstituted or substituted cyclopentadienyl ligands or
cyclopentadienyl-type ligands, heteroatom substituted and/or heteroatom
containing
cyclopentadienyl-type ligands. In additional non-limiting embodiments, the
bulky
ligand LA in formula (I) includes cyclopentaphenanthreneyl ligands,
unsubstituted or
substituted indenyl ligands, benzindenyl ligands, unsubstituted or substituted
fluorenyl ligands, octahydrofluorenyl ligands, cyclooctatetraendiyl ligands,
cyclopentacyclododecene ligands, azenyl ligands, azulene ligands, pentalene
ligands, phosphoyl ligands, phosphinimine, pyrrolyl ligands, pyrozolyl
ligands,
carbazolyl ligands, borabenzene ligands and the like, including hydrogenated
versions thereof, for example tetrahydroindenyl ligands. In other embodiments,
LA
may be any other ligand structure capable of ri-bonding to the metal M, such
embodiments include both r13-bonding and n5-bonding to the metal M. In other
embodiments, LA may comprise one or more heteroatoms, for example, nitrogen,
silicon, boron, germanium, sulfur and phosphorous, in combination with carbon
atoms to form an open, acyclic, or a fused ring, or ring system, for example,
a
heterocyclopentadienyl ancillary ligand. Other non-limiting embodiments for LA
include bulky amides, phosphides, alkoxides, aryloxides, imides, carbolides,
borollides, porphyrins, phthalocyanines, corrins and other polyazomacrocycles.
Non-limiting examples of metal M in formula (I) include Group 4 metals,
titanium, zirconium and hafnium.
In an embodiment of the disclosure, the metal M is titanium, Ti.
The phosphinimine ligand, PI, is defined by formula (II):
(RP)3 P = N - (II)
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wherein the RP groups are independently selected from: a hydrogen atom; a
halogen
atom; 01_20 hydrocarbyl radicals which are unsubstituted or substituted with
one or
more halogen atom(s); a C1-8 alkoxy radical; a C6-10 aryl radical; a C6-10
aryloxy
radical; an amido radical; a silyl radical of formula -Si(Rs)3, wherein the Rs
groups are
independently selected from, a hydrogen atom, a 01-8 alkyl or alkoxy radical,
a C6-10
aryl radical, a C6-10 aryloxy radical, or a germanyl radical of formula -
Ge(RG)3,
wherein the RG groups are defined as Rs is defined in this paragraph.
The leaving group Q is any ligand that can be abstracted from formula (I)
forming a catalyst species capable of polymerizing one or more olefin(s). An
equivalent term for Q is an "activatable ligand", i.e. equivalent to the term
"leaving
group". In some embodiments, Q is a monoanionic labile ligand having a sigma
bond to M. Depending on the oxidation state of the metal, the value for n is 1
or 2
such that formula (I) represents a neutral bulky ligand-metal complex. Non-
limiting
examples of Q ligands include a hydrogen atom, halogens, C1-20 hydrocarbyl
radicals, C1-20 alkoxy radicals, C5-10 aryl oxide radicals; these radicals may
be linear,
branched or cyclic or further substituted by halogen atoms, Ci_io alkyl
radicals,
alkoxy radicals, C6-10 aryl or aryloxy radicals. Further non-limiting examples
of Q
ligands include weak bases such as amines, phosphines, ethers, carboxylates,
dienes, hydrocarbyl radicals having from 1 to 20 carbon atoms. Two Q ligands
may
.. also be joined to one another and form for example, a substituted or
unsubstituted
diene ligand (e.g. 1,3-butadiene); or a delocalized heteroatom containing
group such
as an acetate or acetamidinate group.
In an embodiment of the disclosure, Q is independently selected from the
group consisting of a hydrogen atom, a halogen atom, a Ci-io hydrocarbyl
radical, a
Ci_io alkoxy radical and a C5-10 aryl oxide radical; wherein each of said
hydrocarbyl,
alkoxy, and aryl oxide radicals may be unsubstituted or further substituted by
a
halogen atom, a C1-18 alkyl radical, a C1-8 alkoxy radical, a C6-lo aryl or
aryloxy
radical, an amido radical which is unsubstituted or substituted by up to two
C1-8 alkyl
radicals or a phosphido radical which is unsubstituted or substituted by up to
two C1-8
alkyl radicals
In an embodiment of the disclosure, each Q is independently selected from
the group consisting of a halide atom, a 01-4 alkyl radical and a benzyl
radical. In
another embodiment of the disclosure activatable ligands Q are monoanionic
such
as a halide (e.g. chloride) or a hydrocarbyl (e.g. methyl, benzyl).
14
CA 3057934 2019-10-08
The second single site catalyst component, component (ii), is an alumoxane
co-catalyst that activates component (i) to a cationic complex. An equivalent
term for
"alumoxane" is "aluminoxane"; although the exact structure of this co-catalyst
is
uncertain, subject matter experts generally agree that it is an oligomeric
species that
contain repeating units of the general formula (III):
(R)2A10-(Al(R)-0)n-Al(R)2 (III)
where the R groups may be the same or different linear, branched or cyclic
hydrocarbyl radicals containing 1 to 20 carbon atoms and n is from 0 to about
50. A
non-limiting example of an alumoxane is methyl aluminoxane (or MAO) wherein
each R group in formula (III) is a methyl radical.
The third catalyst component (iii) of the single site catalyst formulation is
an
ionic activator. In general, ionic activators are comprised of a cation and a
bulky
anion; wherein the latter is substantially non-coordinating. Non-limiting
examples of
ionic activators are boron ionic activators that are four coordinate with four
ligands
bonded to the boron atom. Non-limiting examples of boron ionic activators
include
the following formulas (IV) and (V) shown below;
[R5][B(R7)4]- (IV)
where B represents a boron atom, R5 is an aromatic hydrocarbyl (e.g. triphenyl
methyl cation) and each R7 is independently selected from phenyl radicals
which are
unsubstituted or substituted with from 3 to 5 substituents selected from
fluorine
atoms, C1-4 alkyl or alkoxy radicals which are unsubstituted or substituted by
fluorine
atoms; and a silyl radical of formula -Si(R9)3, where each R9 is independently
selected from hydrogen atoms and C1-4 alkyl radicals, and; compounds of
formula
(V);
[(R8)tZH][B(R7)4]- (V)
where B is a boron atom, H is a hydrogen atom, Z is a nitrogen or phosphorus
atom,
t is 2 or 3 and R8 is selected from C1-8 alkyl radicals, phenyl radicals which
are
unsubstituted or substituted by up to three C1-4 alkyl radicals, or one R8
taken
CA 3057934 2019-10-08
together with the nitrogen atom may form an anilinium radical and R7 is as
defined
above in formula (IV).
In both formula (IV) and (V), a non-limiting example of R7 is a
pentafluorophenyl radical. In general, boron ionic activators may be described
as
salts of tetra(perfluorophenyl) boron; non-limiting examples include
anilinium,
carbonium, oxonium, phosphonium and sulfonium salts of
tetra(perfluorophenyl)boron with anilinium and trityl (or triphenylmethylium).
Additional non-limiting examples of ionic activators include: triethylammonium
tetra(phenyl)boron, tripropylammonium tetra(phenyl)boron, tri(n-butyl)ammonium
tetra(phenyl)boron, trimethylammonium tetra(p-tolyl)boron, trimethylammonium
tetra(o-tolyl)boron, tributylammonium tetra(pentafluorophenyl)boron,
tripropylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(m,m-
dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron,
tributylammonium tetra(pentafluorophenyl)boron, tri(n-butyl)ammonium tetra(o-
tolyl)boron, N,N-dimethylanilinium tetra(phenyl)boron, N,N-diethylanilinium
tetra(phenyl)boron, N,N-diethylanilinium tetra(phenyl)n-butylboron, N,N-2,4,6-
pentamethylanilinium tetra(phenyl)boron, di-(isopropyl)ammonium
tetra(pentafluorophenyl)boron, dicyclohexylammonium tetra(phenyl)boron,
triphenylphosphonium tetra(phenyl)boron, tri(methylphenyl)phosphonium
tetra(phenyl)boron, tri(dimethylphenyl)phosphonium tetra(phenyl)boron,
tropillium
tetrakispentafluorophenyl borate, triphenylmethylium tetrakispentafluorophenyl
borate, benzene(diazonium)tetrakispentafluorophenyl borate, tropillium
tetrakis(2,3,5,6-tetrafluorophenyl)borate, triphenylmethylium tetrakis(2,3,5,6-
tetrafluorophenyl)borate, benzene(diazonium) tetrakis(3,4,5-
trifluorophenyl)borate,
tropillium tetrakis(3,4,5 -trifluorophenyl)borate, benzene(diazonium)
tetrakis(3,4,5-
trifluorophenyl)borate, tropillium tetrakis(1,2,2-trifluoroethenyl)borate,
triphenylmethylium tetrakis(1 ,2,2-trifluoroethenyl)borate, benzene(diazonium)
tetrakis(1,2,2-trifluoroethenyl)borate, tropillium tetrakis(2,3,4,5-
tetrafluorophenyl)borate, triphenylmethylium tetrakis(2,3,4,5-
tetrafluorophenyl)borate, and benzene(diazonium) tetrakis(2,3,4,5
tetrafluorophenyl)borate. Readily available commercial ionic activators
include N,N-
dimethylanilinium tetrakispentafluorophenyl borate, and triphenylmethylium
tetrakispentafluorophenyl borate.
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CA 3057934 2019-10-08
The optional fourth catalyst component of the single site catalyst formulation
is a hindered phenol, component (iv). Non-limiting example of hindered phenols
include butylated phenolic antioxidants, butylated hydroxytoluene, 2,4-di-
tertiarybuty1-6-ethyl phenol, 4,4'-methylenebis (2,6-di-tertiary-butylphenol),
1,3, 5-
trimethy1-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene and octadecy1-
3-(3',5'-
di-tert-buty1-4'-hydroxyphenyl) propionate.
To produce an active single site catalyst formulation the quantity and mole
ratios of the three or four components, (i) through (iv) are optimized as
described in
U.S. Pat. No. 9,512,282 which is incorporated by reference into this
application in its
entirety.
Heterogeneous Catalyst Formulations
A number of heterogeneous catalyst formulations are well known to those
skilled in the art, including, as non-limiting examples, Ziegler-Natta and
chromium
catalyst formulations.
In this disclosure, embodiments include an in-line and batch Ziegler-Natta
catalyst formulations. The term "in-line Ziegler-Natta catalyst formulation"
refers to
the continuous synthesis of a small quantity of active Ziegler-Natta catalyst
and
immediately injecting this catalyst into at least one continuously operating
reactor,
where the catalyst polymerizes ethylene and one or more optional a-olefins to
form
an ethylene interpolymer. The terms "batch Ziegler-Natta catalyst formulation"
or
"batch Ziegler-Natta procatalyst" refer to the synthesis of a much larger
quantity of
catalyst or procatalyst in one or more mixing vessels that are external to, or
isolated
from, the continuously operating solution polymerization process. Once
prepared,
the batch Ziegler-Natta catalyst formulation, or batch Ziegler-Natta
procatalyst, is
transferred to a catalyst storage tank. The term "procatalyst" refers to an
inactive
catalyst formulation (inactive with respect to ethylene polymerization); the
procatalyst
is converted into an active catalyst by adding an alkyl aluminum co-catalyst.
As
needed, the procatalyst is pumped from the storage tank to at least one
continuously
operating reactor, where an active catalyst is formed and polymerizes ethylene
and
one or more optional a-olefins to form an ethylene interpolymer. The
procatalyst
may be converted into an active catalyst in the reactor or external to the
reactor.
17
CA 3057934 2019-10-08
A wide variety of chemical compounds can be used to synthesize an active
Ziegler-Natta catalyst formulation. The following describes various chemical
compounds that may be combined to produce an active Ziegler-Natta catalyst
formulation. Those skilled in the art will understand that the embodiments in
this
disclosure are not limited to the specific chemical compound disclosed.
An active Ziegler-Natta catalyst formulation may be formed from: a
magnesium compound, a chloride compound, a metal compound, an alkyl aluminum
co-catalyst and an aluminum alkyl. In Table 1 of this disclosure: "(v)" refers
to
"component (v)" the magnesium compound; the term "(vi)" refers to the
"component
(vi)" the chloride compound; "(vii)" refers to "component (vii)" the metal
compound;
"(viii)" refers to "component (viii)" alkyl aluminum co-catalyst, and; "(ix)"
refers to
"component (ix)" the aluminum alkyl. As will be appreciated by those skilled
in the
art, Ziegler-Natta catalyst formulations may contain additional components; a
non-
limiting example of an additional component is an electron donor, e.g. amines
or
ethers.
A non-limiting example of an active in-line Ziegler-Natta catalyst formulation
can be prepared as follows. In the first step, a solution of a magnesium
compound
(component (v)) is reacted with a solution of the chloride compound (component
(vi))
to form a magnesium chloride support suspended in solution. Non-limiting
examples
.. of magnesium compounds include Mg(R1)2; wherein the R1 groups may be the
same
or different, linear, branched or cyclic hydrocarbyl radicals containing 1 to
10 carbon
atoms. Non-limiting examples of chloride compounds include R2CI; wherein R2
represents a hydrogen atom, or a linear, branched or cyclic hydrocarbyl
radical
containing 1 to 10 carbon atoms. In the first step, the solution of magnesium
compound may also contain an aluminum alkyl (component (ix)). Non-limiting
examples of aluminum alkyl include Al(R3)3, wherein the R3 groups may be the
same
or different, linear, branched or cyclic hydrocarbyl radicals containing from
1 to 10
carbon atoms. In the second step a solution of the metal compound (component
(vii)) is added to the solution of magnesium chloride and the metal compound
is
supported on the magnesium chloride. Non-limiting examples of suitable metal
compounds include M(X)n or MO(X)n; where M represents a metal selected from
Group 4 through Group 8 of the Periodic Table, or mixtures of metals selected
from
Group 4 through Group 8; 0 represents oxygen, and; X represents chloride or
bromide; n is an integer from 3 to 6 that satisfies the oxidation state of the
metal.
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CA 3057934 2019-10-08
Additional non-limiting examples of suitable metal compounds include Group 4
to
Group 8 metal alkyls, metal alkoxides (which may be prepared by reacting a
metal
alkyl with an alcohol) and mixed-ligand metal compounds that contain a mixture
of
halide, alkyl and alkoxide ligands. In the third step a solution of an alkyl
aluminum
co-catalyst (component (viii)) is added to the metal compound supported on the
magnesium chloride. A wide variety of alkyl aluminum co-catalysts are
suitable, as
expressed by formula (VI):
Al(R4)p(0R5)q(X)r (VI)
wherein the R4 groups may be the same or different, hydrocarbyl groups having
from
1 to 10 carbon atoms; the OR5 groups may be the same or different, alkoxy or
aryloxy groups wherein R5 is a hydrocarbyl group having from 1 to 10 carbon
atoms
bonded to oxygen; X is chloride or bromide, and; (p+q+r) = 3, with the proviso
that p
is greater than 0. Non-limiting examples of commonly used alkyl aluminum co-
catalysts include trimethyl aluminum, triethyl aluminum, tributyl aluminum,
dimethyl
aluminum methoxide, diethyl aluminum ethoxide, dibutyl aluminum butoxide,
dimethyl aluminum chloride or bromide, diethyl aluminum chloride or bromide,
dibutyl
aluminum chloride or bromide and ethyl aluminum dichloride or dibromide.
The process described in the paragraph above, to synthesize an active in-line
Ziegler-Natta catalyst formulation, can be carried out in a variety of
solvents; non-
limiting examples of solvents include linear or branched C5 to C12 alkanes or
mixtures thereof.
To produce an active in-line Ziegler-Natta catalyst formulation the quantity
and mole ratios of the five components, (v) through (ix), are optimized as
described
in U.S. Pat. No. 9,512,282 which is incorporated by reference into this
application in
its entirety.
Additional embodiments of heterogeneous catalyst formulations include
formulations where the "metal compound" is a chromium compound; non-limiting
examples include silyl chromate, chromium oxide and chromocene. In some
embodiments, the chromium compound is supported on a metal oxide such as
silica
or alumina. Heterogeneous catalyst formulations containing chromium may also
include co-catalysts; non-limiting examples of co-catalysts include
trialkylaluminum,
alkylaluminoxane and dialkoxyalkylaluminum compounds and the like.
19
CA 3057934 2019-10-08
Solution Polymerization Process
The ethylene interpolymer products disclosed herein, useful in the
manufacture of rotomolded articles, were produced in a continuous solution
polymerization process. This solution process has been fully described in
Canadian
Patent Application No. CA 2,868,640, filed October 21, 2014 and entitled
"SOLUTION POLYMERIZATION PROCESS"; which is incorporated by reference
into this application in its entirety.
Embodiments of this process includes at least two continuously stirred
reactors, R1 and R2 and an optional tubular reactor R3. Feeds (solvent,
ethylene, at
.. least two catalyst formulations, optional hydrogen and optional a-olefin)
are fed to at
least two reactors continuously. A single site catalyst formulation is
injected into R1
and a first heterogeneous catalyst formulation is injected into R2 and
optionally R3.
Optionally, a second heterogeneous catalyst formulation, different from the
first
heterogeneous catalyst formulation, is injected into R3.
R1 and R2 may be operated in series or parallel modes of operation. To be
more clear, in series mode 100% of the effluent from R1 flows directly into
R2. In
parallel mode, R1 and R2 operate independently and the effluents from R1 and
R2
are combined downstream of the reactors.
The single site catalyst formulation includes an ionic activator (component
(iii)), a bulky ligand-metal complex (component (i)), an alumoxane co-catalyst
(component (ii)) and an optional hindered phenol (component (iv)),
respectively.
Injection of the single site catalyst formulation into R1 produces a first
ethylene
interpolymer in the first reactor and provides a first exit stream containing
the first
ethylene interpolymer (exiting R1).
A heterogeneous catalyst formulation is injected into R2. In one embodiment
a first in-line Ziegler-Natta catalyst formulation is injected into R2. A
first in-line
Ziegler-Natta catalyst formulation is formed within a first heterogeneous
catalyst
assembly by optimizing the following molar ratios: (aluminum alkyl)/(magnesium
compound) or (ix)/(v); (chloride compound)/(magnesium compound) or (vi)/(v);
(alkyl
aluminum co-catalyst)/(metal compound) or (viii)/(vii), and; (aluminum
alkyl)/(metal
compound) or (ix)/(vii); as well as the time these compounds have to react and
equilibrate. Within the first heterogeneous catalyst assembly the time between
the
addition of the chloride compound and the addition of the metal compound
CA 3057934 2019-10-08
(component (vii)) is controlled; hereafter HUT-1 (the first Hold-Up-Time). The
time
between the addition of component (vii) and the addition of the alkyl aluminum
co-
catalyst, component (viii), is also controlled; hereafter HUT-2 (the second
Hold-Up-
Time). In addition, the time between the addition of the alkyl aluminum co-
catalyst
.. and the injection of the in-line Ziegler-Natta catalyst formulation into R2
is controlled;
hereafter HUT-3 (the third Hold-Up-Time). Optionally, 100% the alkyl aluminum
co-
catalyst, may be injected directly into R2. Optionally, a portion of the alkyl
aluminum
co-catalyst may be injected into the first heterogeneous catalyst assembly and
the
remaining portion injected directly into R2. The quantity of in-line
heterogeneous
.. catalyst formulation added to R2 is expressed as the parts-per-million
(ppm) of metal
compound (component (vii)) in the reactor solution, hereafter "R2 (vii)
(ppm)".
Injection of the in-line heterogeneous catalyst formulation into R2 produces a
second
ethylene interpolymer in the second reactor and provides a second exit stream
containing the second ethylene interpolymer (exiting R2). In series mode, R2
produces a second exit stream (the stream exiting R2) containing the first
ethylene
interpolymer and the second ethylene interpolymer. Optionally the second exit
stream is deactivated by adding a catalyst deactivator. If the second exit
stream is
not deactivated the second exit stream enters reactor R3. One embodiment of a
suitable R3 design is a tubular reactor. Optionally, one or more of the
following fresh
feeds may be injected into R3; solvent, ethylene, hydrogen, a-olefin and a
first or
second heterogeneous catalyst formulation; the latter is supplied from a
second
heterogeneous catalyst assembly. The chemical composition of the first and
second
heterogeneous catalyst formulations may be the same, or different, i.e. the
catalyst
components ((v) through (ix)), mole ratios and hold-up-times may differ in the
first
and second heterogeneous catalyst assemblies. The second heterogeneous
catalyst assembly generates an efficient catalyst by optimizing hold-up-times
and the
molar ratios of the catalyst components.
In reactor R3, a third ethylene interpolymer may, or may not, form. A third
ethylene interpolymer will not form if a catalyst deactivator is added
upstream of
reactor R3. A third ethylene interpolymer will be formed if a catalyst
deactivator is
added downstream of R3. The optional third ethylene interpolymer may be formed
using a variety of operational modes (with the proviso that catalyst
deactivator is not
added upstream). Non-limiting examples of operational modes include: (a)
residual
ethylene, residual optional a-olefin and residual active catalyst entering R3
react to
21
CA 3057934 2019-10-08
form the third ethylene interpolymer, or; (b) fresh process solvent, fresh
ethylene and
optionally fresh a-olefin are added to R3 and the residual active catalyst
entering R3
forms the third ethylene interpolymer, or; (c) a second in-line heterogeneous
catalyst
formulation is added to R3 to polymerize residual ethylene and residual
optional a-
olefin to form the third ethylene interpolymer, or; (d) fresh process solvent,
ethylene,
optional a-olefin and a second in-line heterogeneous catalyst formulation are
added
to R3 to form the third ethylene interpolymer.
In series mode, R3 produces a third exit stream (the stream exiting R3)
containing the first ethylene interpolymer, the second ethylene interpolymer
and
optionally a third ethylene interpolymer. A catalyst deactivator may be added
to the
third exit stream producing a deactivated solution; with the proviso a
catalyst
deactivator is not added if a catalyst deactivator was added upstream of R3.
The deactivated solution passes through a pressure let down device, a heat
exchanger and a passivator is added forming a passivated solution. The
passivated
solution passes through a series of vapor liquid separators and ultimately the
ethylene interpolymer product enters polymer recovery. Non-limiting examples
of
polymer recovery operations include one or more gear pump, single screw
extruder
or twin screw extruder that forces the molten ethylene interpolymer product
through
a pelletizer.
Embodiments of the manufactured articles disclosed herein, may also be
formed from ethylene interpolymer products synthesized using a batch Ziegler-
Natta
catalyst. Typically, a first batch Ziegler-Natta procatalyst is injected into
R2 and the
procatalyst is activated within R2 by injecting an alkyl aluminum co-catalyst
forming a
first batch Ziegler-Natta catalyst. Optionally, a second batch Ziegler-Natta
procatalyst is injected into R3.
A variety of solvents may be used as the process solvent; non-limiting
examples include linear, branched or cyclic C5 to C12 alkanes. Non-limiting
examples of a-olefins include C3 to C10 a-olefins. It is well known to
individuals of
ordinary experience in the art that reactor feed streams (solvent, monomer, a-
olefin,
hydrogen, catalyst formulation etc.) must be essentially free of catalyst
deactivating
poisons; non-limiting examples of poisons include trace amounts of oxygenates
such
as water, fatty acids, alcohols, ketones and aldehydes. Such poisons are
removed
from reactor feed streams using standard purification practices; non-limiting
22
CA 3057934 2019-10-08
examples include molecular sieve beds, alumina beds and oxygen removal
catalysts
for the purification of solvents, ethylene and a-olefins, etc.
In the continuous polymerization processes described, polymerization is
terminated by adding a catalyst deactivator. The catalyst deactivator
substantially
stops the polymerization reaction by changing active catalyst species to
inactive
forms. Suitable deactivators are well known in the art, non-limiting examples
include:
amines (e.g., U.S. Pat. No. 4,803,259 to Zboril et al.); alkali or alkaline
earth metal
salts of carboxylic acid (e.g., U.S. Pat. No. 4,104,609 to Machan et al.);
water (e.g.,
U.S. Pat. No. 4,731,438 to Bernier et al.); hydrotalcites, alcohols and
carboxylic
acids (e.g., U.S. Pat. No. 4,379,882 to Miyata); or a combination thereof
(U.S. Pat.
No. 6,180,730 to Sibtain et al.).
Prior to entering the vapor/liquid separator, a passivator or acid scavenger
may be added to deactivated solution. Suitable passivators are well known in
the art,
non-limiting examples include alkali or alkaline earth metal salts of
carboxylic acids
or hydrotalcites.
In this disclosure, the number of solution reactors is not particularly
important;
with the proviso that the continuous solution polymerization process comprises
at
least two reactors that employ at least one single-site catalyst formulation
and at
least one heterogeneous catalyst formulation.
The First Ethylene Interpolymer
The first ethylene interpolymer is produced with a single-site catalyst
formulation. If the optional a-olefin is not added to reactor 1 (R1), then the
ethylene
interpolymer produced in R1 is an ethylene homopolymer. If an a-olefin is
added,
the following weight ratio is one parameter to control the density of the
first ethylene
interpolymer: ((a-olefin)/(ethylene))R1. The symbol "al" refers to the density
of the
first ethylene interpolymer produced in R1. In embodiments of the disclosure,
the
upper limit on al may be about 0.955 g/cm3; in some cases about 0.945 g/cm3
and;
in other cases about 0.941 g/cm3. In embodiments of the disclosure, the lower
limit
on al may be about 0.855 g/cm3, in some cases about 0.865 g/cm3, and; in other
cases about 0.875 g/cm3 or about 0.885 g/cm3.
In embodiments of the disclosure the density, al of the first ethylene
interpolymer may be from about 0.865 g/cm3 to about 0.941 g/cm3, or from about
23
CA 3057934 2019-10-08
0.865 g/cm3 to about 0.936 g/cm3, or from about 0.865 g/cm3 to about 0.931
g/cm3,
or from about 0.865 g/cm3 to about 0.926 g/cm3, or from about 0.865 g/cm3 to
about
0.921 g/cm3, or from about 0.865 g/cm3 to about 0.914 g/cm3, or from about
0.865
g/cm3 to about 0.913 g/cm3, or from about 0.865 g/cm3 to about 0.912 g/cm3, or
from
about 0.865 g/cm3 to about 0.910 g/cm3, or from about 0.865 g/cm3 to about
0.906
g/cm3, or from about 0.875 g/cm3 to about 0.941 g/cm3, or from about 0.875
g/cm3 to
about 0.936 g/cm3, or from about 0.875 g/cm3 to about 0.931 g/cm3, or from
about
0.875 g/cm3 to about 0.926 g/cm3, or from about 0.875 g/cm3 to about 0.921
g/cm3,
or from about 0.875 g/cm3 to about 0.914 g/cm3, or from about 0.875 g/cm3 to
about
0.913 g/cm3, or from about 0.875 g/cm3 to about 0.912 g/cm3, or from about
0.875
g/cm3 to about 0.910 g/cm3, or from about 0.875 g/cm3 to about 0.906 g/cm3, or
from
about 0.885 g/cm3 to about 0.941 g/cm3, or from about 0.885 g/cm3 to about
0.936
g/cm3, or from about 0.885 g/cm3 to about 0.931 g/cm3, or from about 0.885
g/cm3 to
about 0.926 g/cm3, or from about 0.885 g/cm3 to about 0.921 g/cm3, or from
about
0.885 g/cm3 to about 0.914 g/cm3, or from about 0.885 g/cm3 to about 0.913
g/cm3,
or from about 0.885 g/cm3 to about 0.912 g/cm3, or from about 0.885 g/cm3 to
about
0.910 g/cm3, or from about 0.885 g/cm3 to about 0.906 g/cm3.
Methods to determine the CDBI50 (Composition Distribution Branching Index)
of an ethylene interpolymer are well known to those skilled in the art. The
CDBI50,
expressed as a percent, is defined as the percent of the ethylene interpolymer
whose comonomer composition is within 50% of the median comonomer
composition. It is also well known to those skilled in the art that the CDBI50
of
ethylene interpolymers produced with single-site catalyst formulations are
higher
relative to the CDBI50 of a-olefin containing ethylene interpolymers produced
with
heterogeneous catalyst formulations. In embodiments of the disclosure, the
upper
limit on the CDBI50 of the first ethylene interpolymer (produced with a single-
site
catalyst formulation) may be about 98%, in other cases about 95% and in still
other
cases about 90%. In embodiments of the disclosure, the lower limit on the
CDBI50 of
the first ethylene interpolymer may be about 70%, in other cases about 75% and
in
.. still other cases about 80%.
As is well known to those skilled in the art the Mw/Mn of ethylene
interpolymers
produced with single site catalyst formulations are lower relative to ethylene
interpolymers produced with heterogeneous catalyst formulations. Thus, in the
24
CA 3057934 2019-10-08
embodiments disclosed, the first ethylene interpolymer has a lower Mw/Mn
relative to
the second ethylene interpolymer; where the second ethylene interpolymer is
produced with a heterogeneous catalyst formulation. In embodiments of the
disclosure, the upper limit on the Mw/Mn of the first ethylene interpolymer
may be
about 2.8, in other cases about 2.5 and in still other cases about 2.2. In
embodiments of the disclosure, the lower limit on the Mw/Mn the first ethylene
interpolymer may be about 1.7, in other cases about 1.8 and in still other
cases
about 1.9.
In embodiments of the disclosure, the first ethylene interpolymer has a
molecular weight distribution, Mw/Mn of from about 1.7 to about 2.3, or from
about 1.8
to about 2.3, of from about 1.8 to about 2.2, or about 2Ø
The first ethylene interpolymer contains catalyst residues that reflect the
chemical composition of the single-site catalyst formulation used. Those
skilled in
the art will understand that catalyst residues are typically quantified by the
parts per
million of metal in the first ethylene interpolymer, where metal refers to the
metal in
component (i), i.e. the metal in the "bulky ligand-metal complex"; hereafter
this metal
will be referred to "metal A". As recited earlier in this disclosure, non-
limiting
examples of metal A include Group 4 metals, titanium, zirconium and hafnium.
In
embodiments of the disclosure, the upper limit on the ppm of metal A in the
first
ethylene interpolymer may be about 1.0 ppm, in other cases about 0.9 ppm and
in
still other cases about 0.8 ppm. In embodiments of the disclosure, the lower
limit on
the ppm of metal A in the first ethylene interpolymer may be about 0.01 ppm,
in other
cases about 0.1 ppm and in still other cases about 0.2 ppm.
The amount of hydrogen added to R1 can vary over a wide range allowing the
continuous solution process to produce first ethylene interpolymers that
differ greatly
in melt index, 121 (melt index is measured at 190 C using a 2.16 kg load
following the
procedures outlined in ASTM D1238). The quantity of hydrogen added to R1 is
expressed as the parts-per-million (ppm) of hydrogen in R1 relative to the
total mass
in reactor R1; hereafter H2R1 (ppm). In embodiments of the disclosure, the
upper
limit on 121 may be about 200 dg/min, in some cases about 100 dg/min; in other
cases about 50 dg/min, and; in still other cases about 1 dg/min. In
embodiments, the
lower limit on 121 may be about 0.01 dg/min, in some cases about 0.05 dg/min;
in
other cases about 0.1 dg/min, and; in still other cases about 0.5 dg/min, or
about 1.0
dg/min.
CA 3057934 2019-10-08
In embodiments of the disclosure, the first ethylene interpolymer has a
number average molecular weight, Mn of from about 7,500 to about 75,000, or
from
about 10,000 to about 65,000, or from about 15,000 to about 50,000, or from
about
20,000 to about 50,000, or from about 25,000 to about 50,000, or from about
30,000
to about 50,000.
In embodiments of the disclosure, the upper limit on the weight percent (wt%)
of the first ethylene interpolymer in the ethylene interpolymer product may be
about
75 wt%, or about 60 wt%, in other cases about 55 wt% and in still other cases
about
50 wt%. In embodiments of the disclosure, the lower limit on the wt% of the
first
ethylene interpolymer in the ethylene interpolymer product may be about 15
wt%; in
other cases about 25 wt% and in still other cases about 30 wt%.
The Second Ethylene Interpolymer
The second ethylene interpolymer is produced with a heterogeneous catalyst
formulation. If optional a-olefin is not added to reactor 2 (R2) either by
adding fresh
a-olefin to R2 (or carried over from R1) then the ethylene interpolymer
produced in
R2 is an ethylene homopolymer. If an optional a-olefin is present in R2, the
following
weight ratio is one parameter to control the density of the second ethylene
interpolymer produced in R2: ((a-olefin)/(ethylene))R2. Hereafter, the symbol
"a2"
refers to the density of the ethylene interpolymer produced in R2. In
embodiments
of the disclosure, the upper limit on a2 may be about 0.965 g/cm3; in some
cases
about 0.955 g/cm3 and; in other cases about 0.945 g/cm3. Depending on the
heterogeneous catalyst formulation used, in embodiments of the disclosure, the
lower limit on a2 may be about 0.875 g/cm3, or about 0.885 g/cm3, in some
cases
about 0.900 g/cm3, and; in other cases about 0.906 g/cm3.
In embodiments of the disclosure the density, cr2 of the second ethylene
interpolymer is from about 0.875 g/cm3 to about 0.941 g/cm3, or from about
0.875
g/cm3 to about 0.936 g/cm3, or from about 0.875 g/cm3 to about 0.931 g/cm3, or
from
about 0.875 g/cm3 to about 0.926 g/cm3, or from about 0.875 g/cm3 to about
0.921
g/cm3, or from about 0.875 g/cm3 to about 0.914 g/cm3, or from about 0.875
g/cm3 to
about 0.913 g/cm3, or from about 0.875 g/cm3 to about 0.912 g/cm3, or from
about
0.885 g/cm3 to about 0.941 g/cm3, or from about 0.885 g/cm3 to about 0.936
g/cm3,
or from about 0.885 g/cm3 to about 0.931 g/cm3, or from about 0.885 g/cm3 to
about
26
CA 3057934 2019-10-08
0.926 g/cm3, or from about 0.885 g/cm3 to about 0.921 g/cm3, or from about
0.885
g/cm3 to about 0.914 g/cm3, or from about 0.885 g/cm3 to about 0.913 g/cm3, or
from
about 0.885 g/cm3 to about 0.912 g/cm3, or from about 0.895 g/cm3 to about
0.941
g/cm3, or from about 0.895 g/cm3 to about 0.936 g/cm3, or from about 0.895
g/cm3 to
about 0.931 g/cm3, or from about 0.895 g/cm3 to about 0.926 g/cm3, or from
about
0.895 g/cm3 to about 0.921 g/cm3, or from about 0.895 g/cm3 to about 0.914
g/cm3,
or from about 0.895 g/cm3 to about 0.913 g/cm3, or from about 0.895 g/cm3 to
about
0.912 g/cm3.
A heterogeneous catalyst formulation is used to produce the second ethylene
interpolymer. If the second ethylene interpolymer contains an a-olefin, the
CDBI50 of
the second ethylene interpolymer is lower relative to the CDBI50 of the first
ethylene
interpolymer that was produced with a single-site catalyst formulation. In an
embodiment of this disclosure, the upper limit on the CDBI50 of the second
ethylene
interpolymer (that contains an a-olefin) may be about 70%, in other cases
about 65%
.. and in still other cases about 60%. In an embodiment of this disclosure,
the lower
limit on the CDBI50 of the second ethylene interpolymer (that contains an a-
olefin)
may be about 40% or 45%, in other cases about 50% and in still other cases
about
55%. If an a-olefin is not added to the continuous solution polymerization
process
the second ethylene interpolymer is an ethylene homopolymer. In the case of a
.. homopolymer, which does not contain a-olefin, one can still measure a
CDBI50 using
TREF. In the case of a homopolymer, the upper limit on the CDBI50 of the
second
ethylene interpolymer may be about 98%, in other cases about 96% and in still
other
cases about 95%, and; the lower limit on the CDBI50 may be about 88%, in other
cases about 89% and in still other cases about 90%. It is well known to those
skilled
in the art that as the a-olefin content in the second ethylene interpolymer
approaches
zero, there is a smooth transition between the recited CDBI50 limits for the
second
ethylene interpolymers (that contain an a-olefin) and the recited CDBI50
limits for the
second ethylene interpolymers that are ethylene homopolymers. Typically, the
CDBI50 of the first ethylene interpolymer is higher than the CDBI50 of the
second
ethylene interpolymer.
In an embodiment of the disclosure, the second ethylene interpolymer is a
made with a first Ziegler-Natta catalyst formulation.
27
CA 3057934 2019-10-08
The Mw/Mn of second ethylene interpolymer is higher than the Mw/Mn of the
first ethylene interpolymer. In embodiments of the disclosure, the upper limit
on the
Mw/Mn of the second ethylene interpolymer may be about 4.4, in other cases
about
4.2 and in still other cases about 4Ø In embodiments of the disclosure, the
lower
limit on the Mw/Mn of the second ethylene interpolymer may be about 2.2.
Mw/Mn's of
2.2 may be observed when the melt index, 12 of the second ethylene
interpolymer is
high, or when the melt index, 12 of the ethylene interpolymer product is high,
e.g.
greater than 10 g/1 0 minutes. In other embodiments of the disclosure, the
lower limit
on the Mw/Mn of the second ethylene interpolymer may be about 2.4 and in still
other
cases about 2.6.
In embodiments of the disclosure, the second ethylene interpolymer has a
molecular weight distribution, Mw/Mn or from 2.3 to 5.5, or from 2.3 to 5.0,
or from 2.3
to 4.5, or from 2.3 to 4.0, or from 2.3 to 3.5, or from 2.3 to 3.0, or from
2.5 to 5.0, or
from 2.5 to 4.5, or from 2.5 to 4.0, or from 2.5 to 3.5.
The second ethylene interpolymer contains catalyst residues that reflect the
chemical composition of the heterogeneous catalyst formulation. Those skilled
in the
art with understand that heterogeneous catalyst residues are typically
quantified by
the parts per million of metal in the second ethylene interpolymer, where the
metal
refers to the metal originating from component (vii), i.e. the "metal
compound";
hereafter (and in the claims) this metal will be referred to as "metal B". As
recited
earlier in this disclosure, non-limiting examples of metal B include metals
selected
from Group 4 through Group 8 of the Periodic Table, or mixtures of metals
selected
from Group 4 through Group 8. In embodiments of the disclosure, the upper
limit on
the ppm of metal B in the second ethylene interpolymer may be about 12 ppm, in
other cases about 10 ppm and in still other cases about 8 ppm. In embodiments
of
the disclosure, the lower limit on the ppm of metal B in the second ethylene
interpolymer may be about 0.5 ppm, in other cases about 1 ppm and in still
other
cases about 3 ppm. While not wishing to be bound by any particular theory, in
series
mode of operation it is believed that the chemical environment within the
second
reactor deactivates the single site catalyst formulation, or; in parallel mode
of
operation the chemical environment within R2 deactivates the single site
catalyst
formulation.
The amount of hydrogen added to R2 can vary over a wide range which
allows the continuous solution process to produce second ethylene
interpolymers
28
CA 3057934 2019-10-08
that differ greatly in melt index, hereafter 122. The quantity of hydrogen
added is
expressed as the parts-per-million (ppm) of hydrogen in R2 relative to the
total mass
in reactor R2; hereafter H2R2 (ppm). In embodiments of the disclosure, the
upper
limit on 122 may be about 1000 dg/min; in some cases about 750 dg/min; in
other
cases about 500 dg/min, and; in still other cases about 200 dg/min. In
embodiments
of the disclosure, the lower limit on 122 may be about 0.3 dg/min, in some
cases about
0.4 dg/min, in other cases about 0.5 dg/min, and; in still other cases about
0.6
dg/min or about 1.0 dg/min.
In embodiments of the disclosure, the second ethylene interpolymer has a
number average molecular weight, Mn of from about 5,000 to about 75,000, or
from
about 5,000 to about 50,000, or from about 10,000 to about 50,000, or from
about
15,000 to about 50,000, or from about 15,000 to about 35,000, or from about
20,000
to about 30,000.
In embodiments of the disclosure, the upper limit on the weight percent (wt%)
of the second ethylene interpolymer in the ethylene interpolymer product may
be
about 85 wt%, in other cases about 80 wt% and in still other cases about 75
wt%, or
about 70 wt%. In embodiments of the disclosure, the lower limit on the wt% of
the
second ethylene interpolymer in the ethylene interpolymer product may be about
20
wt%, or about 30 wt%; in other cases about 40 wt% and in still other cases
bout 45
wt%.
The Third Ethylene Interpolymer
In an embodiment of the disclosure, a heterogeneous catalyst formulation is
used to produce the third ethylene interpolymer.
A third ethylene interpolymer is not produced in R3 if a catalyst deactivator
is
added upstream of R3. If a catalyst deactivator is not added and optional a-
olefin is
not present then the third ethylene interpolymer produced in R3 is an ethylene
homopolymer. If a catalyst deactivator is not added and optional a-olefin is
present
in R3, the following weight ratio determines the density of the third ethylene
interpolymer: ((a-olefin)/(ethylene))R3. In the continuous solution
polymerization
process ((a-olefin)/(ethylene))R3 is one of the control parameter used to
produce a
third ethylene interpolymer with a desired density. Hereafter, the symbol
"(53" refers
to the density of the ethylene interpolymer produced in R3. In embodiments of
the
29
CA 3057934 2019-10-08
disclosure, the upper limit on a3 may be about 0.975 g/cm3; in some cases
about
0.965 g/cm3 and; in other cases about 0.955 g/cm3. Depending on the
heterogeneous catalyst formulations used, in embodiments of the disclosure,
the
lower limit on a3may be about 0.89 g/cm3, in some cases about 0.90 g/cm3, and;
in
other cases about 0.91 g/cm3.
Optionally, a second heterogeneous catalyst formulation (i.e. different from
the one used to make the second ethylene interpolymer) may be added to R3.
If the third ethylene interpolymer contains an a-olefin, the upper limit on
the
CDBI50 of the optional third ethylene interpolymer may be about 70% or about
65%,
in other cases about 60% and in still other cases about 55%. The CDBI50 of an
a-
olefin containing optional third ethylene interpolymer will be lower than the
CDBI50 of
the first ethylene interpolymer produced with the single-site catalyst
formulation.
Typically, the lower limit on the CDBI50 of the optional third ethylene
interpolymer
(containing an a-olefin) may be about 35%, in other cases about 40% and in
still
other cases about 45%. If an a-olefin is not added to the continuous solution
polymerization process the optional third ethylene interpolymer is an ethylene
homopolymer. In the case of an ethylene homopolymer the upper limit on the
CDB150 may be about 98%, in other cases about 96% and in still other cases
about
95%, and; the lower limit on the CDBI50 may be about 88%, in other cases about
89% and in still other cases about 90%. Typically, the CDBI50 of the first
ethylene
interpolymer is higher than the CDBI50 of the third ethylene interpolymer and
second
ethylene interpolymer.
In an embodiment, the third ethylene interpolymer is made using a
heterogeneous catalyst which is a first Ziegler-Natta catalyst formulation
(i.e. a
Ziegler-Natta catalyst formulation analogous to the one used to make the
second
ethylene interpolymer) or a second Ziegler-Natta catalyst formulation which is
different from the first Ziegler-Natta catalyst formulation.
In embodiments of the disclosure, the upper limit on the Mw/Mn of the optional
third ethylene interpolymer may be about 5.0, in other cases about 4.8 and in
still
other cases about 4.5. In embodiments of the disclosure, the lower limit on
the
Mw/Mn of the optional third ethylene interpolymer may be about 2.2, in other
cases
about 2.4 and in still other cases about 2.6. In an embodiment, the Mw/Mn of
the
CA 3057934 2019-10-08
optional third ethylene interpolymer is higher than the Mw/Mn of the first
ethylene
interpolymer.
The catalyst residues in the optional third ethylene interpolymer reflect the
chemical composition of the heterogeneous catalyst formulation(s) used, i.e.
the first
and optionally a second heterogeneous catalyst formulation. The chemical
compositions of the first and second heterogeneous catalyst formulations may
be the
same or different; for example a first component (vii) and a second component
(vii)
may be used to synthesize the first and second heterogeneous catalyst
formulation.
As recited above, "metal B" refers to the metal that originates from the first
component (vii). Hereafter, "metal C" refers to the metal that originates from
the
second component (vii). Metal B and optional metal C may be the same, or
different.
Non-limiting examples of metal B and metal C include metals selected from
Group 4
through Group 8 of the Periodic Table, or mixtures of metals selected from
Group 4
through Group 8. In embodiments of the disclosure, the upper limit on the ppm
of
(metal B + metal C) in the optional third ethylene interpolymer may be about
12 ppm,
in other cases about 10 ppm and in still other cases about 8 ppm. In
embodiments
of the disclosure, the lower limit on the ppm of (metal B + metal C) in the
optional
third ethylene interpolymer may be about 0.5 ppm, in other cases about 1 ppm
and
in still other cases about 3 ppm.
Optionally hydrogen may be added to R3. Adjusting the amount of hydrogen
in R3, hereafter H2R3 (ppm), allows the continuous solution process to produce
third
ethylene interpolymers that differ widely in melt index, hereafter 12. In
embodiments of the disclosure, the upper limit on l2 may be about 2000 dg/min;
in
some cases about 1500 dg/min; in other cases about 1000 dg/min, and; in still
other
cases about 500 dg/min. In embodiments of the disclosure, the lower limit on
12 may
be about 0.5 dg/min, in some cases about 0.6 dg/min, in other cases about 0.7
dg/min, and; in still other cases about 0.8 dg/min.
In embodiments of the disclosure, the upper limit on the weight percent (wt%)
of the optional third ethylene interpolymer in the ethylene interpolymer
product may
be about 30 wt%, in other cases about 25 wt% and in still other cases about 20
wt%.
In embodiments of the disclosure, the lower limit on the wt % of the optional
third
ethylene interpolymer in the ethylene interpolymer product may be 0 wt%; in
other
cases about 5 wt% and in still other cases about 10 wt%.
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CA 3057934 2019-10-08
The Ethylene Interpolymer Product
The ethylene interpolymer product used in this disclosure includes a first
ethylene interpolymer made with a single site catalyst and a second ethylene
interpolymer made with a heterogeneous catalyst.
In an embodiment the ethylene interpolymer product used in this disclosure
includes a third ethylene interpolymer made with a heterogeneous catalyst.
In embodiment of the disclosure, the ethylene interpolymer product is made
using a solution polymerization process.
In an embodiment of the disclosure, the ethylene interpolymer product
comprises ethylene and one or more alpha-olefins.
In an embodiment of the disclosure, the ethylene interpolymer product
comprises ethylene and 1-octene.
In embodiments of the disclosure, the upper limit on the density of the
ethylene interpolymer product may be about 0.920 g/cm3, or less than about
0.920
g/cm3, or about 0.914 g/cm3, or less than about 0.914 g/cm3, or about 0.912
g/cm3, or
less than about 0.912 g/cm3. In embodiments of the disclosure, the lower limit
on
the density of the ethylene interpolymer product may be about 0.905 g/cm3, or
about
0.910 g/cm3.
The upper limit on the CDBI50 of the ethylene interpolymer product may in
embodiments of the disclosure be about 97%, in other cases about 90% and in
still
other cases about 85%. An ethylene interpolymer product with a CDBI50 of 97%
may
result if an a-olefin is not added to the continuous solution polymerization
process; in
this case, the ethylene interpolymer product is an ethylene homopolymer. In
embodiments of the disclosure, the lower limit on the CDBI50 of an ethylene
interpolymer may be about 20%, in other cases about 40% and in still other
cases
about 60%, or about 65%.
In embodiments of the disclosure, the upper limit on the Mw/Mn of the ethylene
interpolymer product may be about 10.0, in other cases about 5.0, or about
4.0, or
about 3Ø In embodiments of the disclosure, the lower limit on the Mw/Mn of
the
ethylene interpolymer product may be 2.0, in other cases about 2.2 and in
still other
cases about 2.4.
In an embodiments of the disclosure, the Mw/Mn of the ethylene interpolymer
product is less than about 4.0, or less than about 3.5, or less than about
3Ø
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CA 3057934 2019-10-08
In an embodiment of the disclosure, the ethylene interpolymer product
comprises three melting peaks when analyzed by differential scanning
calorimetry
(DSC).
In an embodiment of the disclosure, the ethylene interpolymer product
comprises three melting peaks when analyzed by differential scanning
calorimetry
(DSC) and each of the three melting peaks have a minimum at a temperature of
100 C or greater.
In an embodiment of the disclosure, the ethylene interpolymer product has a
unimodal profile in a gel permeation chromatograph generated according to the
method of ASTM D6474-99. The term "unimodal" is herein defined to mean there
will be only one significant peak or maximum evident in the GPC-curve. A
unimodal
profile includes a broad unimodal profile. In contrast, the use of the term
"bimodal" is
meant to convey that in addition to a first peak, there will be a secondary
peak or
shoulder which represents a higher or lower molecular weight component (i.e.
the
molecular weight distribution, can be said to have two maxima in a molecular
weight
distribution curve). Alternatively, the term "bimodal" connotes the presence
of two
maxima in a molecular weight distribution curve generated according to the
method
of ASTM D6474-99. The term "multi-modal" denotes the presence of two or more,
typically more than two, maxima in a molecular weight distribution curve
generated
according to the method of ASTM D6474-99.
In embodiments of the disclosure, the ethylene interpolymer product will have
a normal or a flat comonomer distribution profile as measured using GPC-FTIR.
If
the comonomer incorporation decreases with molecular weight, as measured using
GPC-FTIR, the distribution is described as "normal". If the comonomer
incorporation
is approximately constant with molecular weight, as measured using GPC-FTIR,
the
comonomer distribution is described as "flat" or "uniform". The terms "reverse
comonomer distribution" and "partially reverse comonomer distribution" mean
that in
the GPC-FTIR data obtained for a copolymer, there is one or more higher
molecular
weight components having a higher comonomer incorporation than in one or more
lower molecular weight components. The term "reverse(d) comonomer
distribution"
is used herein to mean, that across the molecular weight range of an ethylene
copolymer, comonomer contents for the various polymer fractions are not
substantially uniform and the higher molecular weight fractions thereof have
proportionally higher comonomer contents (i.e. if the comonomer incorporation
rises
33
CA 3057934 2019-10-08
with molecular weight, the distribution is described as "reverse" or
"reversed").
Where the comonomer incorporation rises with increasing molecular weight and
then
declines, the comonomer distribution is still considered "reverse", but may
also be
described as "partially reverse". A partially reverse comonomer distribution
will
exhibit a peak or maximum.
The catalyst residues in the ethylene interpolymer product reflect the
chemical
compositions of: the single-site catalyst formulation employed in R1; the
first
heterogeneous catalyst formulation employed in R2, and; optionally the first
or
optionally the first and/or second heterogeneous catalyst formulation employed
in
R3. In this disclosure, catalyst residues were quantified by measuring the
parts per
million of catalytic metal in the ethylene interpolymer products. In addition,
the
elemental quantities (ppm) of magnesium, chlorine and aluminum were
quantified.
Catalytic metals originate from two or optionally three sources, specifically:
1) "metal
A" that originates from component (i) that was used to form the single-site
catalyst
formulation; (2) "metal B" that originates from the first component (vii) that
was used
to form the first heterogeneous catalyst formulation, and; (3) optionally
"metal C" that
originates from the second component (vii) that was used to form the optional
second heterogeneous catalyst formulation. Metals A, B and C may be the same
or
different. In this disclosure the term "total catalytic metal" is equivalent
to the sum of
catalytic metals A+B+C. Further, in this disclosure the terms "first total
catalytic
metal" and "second total catalyst metal" are used to differentiate between the
first
ethylene interpolymer product of this disclosure and a comparative
"polyethylene
composition" that were produced using different catalyst formulations.
In embodiments of the disclosure, the upper limit on the ppm of metal A in the
ethylene interpolymer product may be about 0.6 ppm, in other cases about 0.5
ppm
and in still other cases about 0.4 ppm. In embodiments of the disclosure, the
lower
limit on the ppm of metal A in the ethylene interpolymer product may be about
0.001
ppm, in other cases about 0.01 ppm and in still other cases about 0.03 ppm. In
embodiments of the disclosure, the upper limit on the ppm of (metal B + metal
C) in
the ethylene interpolymer product may be about 11 ppm, in other cases about 9
ppm
and in still other cases about 7 ppm. In embodiments of the disclosure, the
lower
limit on the ppm of (metal B + metal C) in the ethylene interpolymer product
may be
about 0.5 ppm, in other cases about 1 ppm and in still other cases about 3
ppm.
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CA 3057934 2019-10-08
In some embodiments, ethylene interpolymers may be produced where the
catalytic metals (metal A, metal B and metal C) are the same metal; a non-
limiting
example would be titanium. In such embodiments, the ppm of (metal B + metal C)
in
the ethylene interpolymer product is calculated using equation (VII):
ppm(B+c) = ((ppm) _ (fA x ppmA))/(i_fA) (VII)
where: ppm(13+c) is the calculated ppm of (metal B + metal C) in the ethylene
interpolymer product; ppM(A+B+C) is the total ppm of catalyst residue in the
ethylene
interpolymer product as measured experimentally, i.e. (metal A ppm + metal B
ppm
+ metal C ppm); fA represents the weight fraction of the first ethylene
interpolymer in
the ethylene interpolymer product, fA may vary from about 0.15 to about 0.6,
and;
ppmA represents the ppm of metal A in the first ethylene interpolymer. In
equation
(VII) ppm' is assumed to be 0.35 ppm.
Embodiments of the ethylene interpolymer products disclosed herein have
lower catalyst residues relative to the polyethylene polymers described in US
6,277,931. Higher catalyst residues in U.S. 6,277,931 increase the complexity
of the
continuous solution polymerization process; an example of increased complexity
includes additional purification steps to remove catalyst residues from the
polymer.
In contrast, in the present disclosure, catalyst residues are not removed. In
embodiments of this disclosure, the upper limit on the "total catalytic
metal", i.e. the
total ppm of (metal A ppm + metal B ppm + optional metal C ppm) in the
ethylene
interpolymer product may be about 11 ppm, in other cases about 9 ppm and in
still
other cases about 7, and; the lower limit on the total ppm of catalyst
residuals (metal
A + metal B + optional metal C) in the ethylene interpolymer product may be
about
0.5 ppm, in other cases about 1 ppm and in still other cases about 3 ppm.
In embodiments of the disclosure, the ethylene interpolymer products are
further characterized by having ?. 3 parts per million (ppm) of total
catalytic metal (Ti);
where the quantity of catalytic metal was determined by Neutron Activation
Analysis
(N.A.A.) as specified herein.
In embodiments of the disclosure, the upper limit on melt index, 12 of the
ethylene interpolymer product is about 10.0 g/10min, or about 8.0 g/10min, or
about
7.5 g/10min, or about 6.0 g/10min, or about 5.0 g/10min, or about 4.5 g/10min.
In
embodiments of the disclosure, the lower limit on the melt index, 12 of the
ethylene
CA 3057934 2019-10-08
interpolymer product is about 1.5 g/10min, or about 2.0 g/10min, or about 2.5
g/10min, or about 3.0 g/10min.
In embodiments of the disclosure, the ethylene interpolymer products are
further characterized by a terminal vinyl unsaturation greater than or equal
to 0.024
terminal vinyl groups per 100 carbon atoms (_?. 0.024 terminal vinyls/100
Carbon
backbone atoms); as determine via Fourier Transform Infrared (FTIR)
spectroscopy
according to ASTM D3124-98 and ASTM D6248-98.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a flexural secant
modulus
at 1%, of less than 600 MPa, or less than 500 MPa, or less than 400 MPa, or
less
than 350 MPa, or less than 300 MPa, or less than 250 MPa.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a tensile secant
modulus at
1%, of less than 600 MPa, or less than 500 MPa, or less than 400 MPa, or less
than
350 MPa, or less than 300 MPa, or less than 250 MPa.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a tensile elongation at
yield
of greater than 12%, or greater than 13%, or greater than 14%, or greater than
15%,
or greater than 16%, or at least 16%.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a VICAT softening
temperature of less than 100 C, or less than 97 C, or less than 95 C.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a VICAT softening
temperature of from 85 C to 100 C, of from 85 C to 99 C, or from 85 C to 97 C,
or
from 85 C to 96 C, or from 85 C to 95 C, or from 85 C to 94 C.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has an upper limit for the
VICAT softening temperature of less than 100 C, or less than 97 C, or less
than
95 C.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a lower limit for the
VICAT
softening temperature of 85 C.
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CA 3057934 2019-10-08
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a Shore D hardness
score
of less than 75, or less than 65, or less than 60, or 5 65, or 5 60.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a Shore D hardness
score
of from 42 to less than 75, or from 42 to less than 65, or from 42 to less
than 60, or
from 42 to 65, or from 42 to 60.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a Shore D hardness
score
with an upper limit of less than 75, or less than 65, or less than 60, or 5
65, or 5 60.
In embodiments of the disclosure, the ethylene interpolymer product or a
plaque made from the ethylene interpolymer product has a Shore D hardness
score
with a lower limit of 42.
In embodiments of the disclosure, the ethylene interpolymer has a zero shear
viscosity, io at 190 C of from about 750 Pa.s to about 6000 Pa.s, or from
about 1000
Pa.s to about 5500 Pa.s, or from about 1000 Pa.s to about 5000 Pa.s, or from
about
1000 Pa.s to about 4000 Pa.s, or from about 1000 Pa.s to about 3500 Pa.s, or
from
about 1000 Pa.s to about 3000 Pa.s, or from about 1500 Pa.s to about 3500
Pa.s, or
from about 1500 Pa.s to about 3000 Pa.s.
In embodiments of the disclosure, the ethylene interpolymer product has a
relative elasticity, defined as the ratio of G' over G" at a frequency of 0.05
rad/s (and
at 190 C), of less than 0.50, or less than 0.40, or less than 0.30, or less
than 0.20, or
less than 0.10, or less than 0.050, or 5 0.10, or 5 0.050, or 5. 0.025, or 5
0.020.
In embodiments of the disclosure, the ethylene interpolymer product has a
melt strength of at least 0.8 cN, or at least 0.85 cN, or at least 0.9 cN.
In embodiments of the disclosure, the ethylene interpolymer product has a
melt strength stretch ratio of greater than 1200, or greater than 1300, or
greater than
1400, or greater than 1500, or greater than 1600, or greater than 1700 or at
least
1200, or at least 1300, or at least 1400, or at least 1500, or at least 1600,
or at least
1700.
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CA 3057934 2019-10-08
Dilution Index (Yd) of Ethylene Interpolymer Products
The Dilution Index, Yd (having dimensions of degrees, ) of an ethylene
interpolymer product as described herein, is defined in U.S. Pat. Appl. No.
2018/0298170 which is incorporated herein in its entirety.
A comparative polymer sample, "Comparative S" was used as the rheological
reference in the Dilution Index test protocol. Comparative S is an ethylene
interpolymer product comprising an ethylene interpolymer synthesized using an
in-
line Ziegler-Natta catalyst in one solution reactor, i.e. SCLAIR FP120-C
which is an
ethylene/1-octene interpolymer available from NOVA Chemicals Company (Calgary,
Alberta, Canada).
The following defines the Dilution Index (Yd). In addition to having molecular
weights, molecular weight distributions and branching structures, blends of
ethylene
interpolymers may exhibit a hierarchical structure in the melt phase. In other
words,
the ethylene interpolymer components may be, or may not be, homogeneous down
to the molecular level depending on interpolymer miscibility and the physical
history
of the blend. Such hierarchical physical structure in the melt is expected to
have a
strong impact on flow and hence on processing and converting; as well as the
end-
use properties of manufactured articles. The nature of this hierarchical
physical
structure between interpolymers can be characterized.
The hierarchical physical structure of ethylene interpolymers can be
characterized using melt rheology. A convenient method can be based on the
small
amplitude frequency sweep tests. Such rheology results are expressed as the
phase
angle g as a function of complex modulus G*, referred to as van Gurp-Palmen
plots
(as described in M. Van Gurp, J. Palmen, Rheol. Bull. (1998) 67(1): 5-8, and;
Dealy
J, Plazek D. Rheol. Bull. (2009) 78(2): 16-31). For a typical ethylene
interpolymer,
the phase angle g increases toward its upper bound of 900 with G* becoming
sufficiently low. A typical VGP plot is shown in Figure 4 of U.S. Pat. Appl.
No.
2018/0298170 which is incorporated herein in its entirety. The VGP plots are a
signature of resin architecture. The rise of 6' toward 90 is monotonic for an
ideally
linear, monodisperse interpolymer. The (GI') for a branched interpolymer or a
blend containing a branched interpolymer may show an inflection point that
reflects
the topology of the branched interpolymer (see S. Trinkle, P. Walter, C.
Friedrich,
Rheo. Acta (2002) 41: 103-113). The deviation of the phase angle g from the
38
CA 3057934 2019-10-08
monotonic rise may indicate a deviation from the ideal linear interpolymer
either due
to presence of long chain branching if the inflection point is low (e.g., 6
200) or a
blend containing at least two interpolymers having dissimilar branching
structure if
the inflection point is high (e.g., 6 70 ).
For commercially available linear low density polyethylenes, inflection points
are not observed; with the exception of some commercial polyethylenes that
contain
a small amount of long chain branching (LCB). To use the VGP plots regardless
of
presence of LCB, an alternative is to use the point where the frequency co, is
two
decades below the cross-over frequency co, i.e., co, = 0.01cox. The cross-over
point
is taken as the reference as it is known to be a characteristic point that
correlates
with MI, density and other specifications of an ethylene interpolymer. The
cross-over
modulus is related to the plateau modulus for a given molecular weight
distribution
(see S. Wu. J Polym Sci, Polym Phys Ed (1989) 27:723; M.R. Nobile, F.
Cocchini.
Rheol Acta (2001) 40:111). The two-decade shift in phase angle 8is to find the
comparable points where the individual viscoelastic responses of constituents
could
be detected; to be more clear, this two decade shift is shown in Figure 5 of
U.S. Pat.
Appl. No. 2018/0298170 which is incorporated herein in its entirety. The
complex
modulus Gc* for this point is normalized to the cross-over modulus, GI / (V2),
as
()GIG, to minimize the variation due to overall molecular weight, molecular
weight distribution and the short chain branching. As a result, the
coordinates on
VGP plots for this low frequency point at co, = 0.01(0,, namely (1,r2-)G,*/Gx*
and 8,,
characterize the contribution due to blending. Similar to the inflection
points, the
closer the (()GIG, (5c) point is toward the 90 upper bound, the more the
blend
behaves as if it were an ideal single component.
As an alternative way to avoid interference due to the molecular weight,
molecular weight distribution and the short branching of the ethylene 8,
interpolymer
ingredients, the coordinates (G,* , 8) are compared to a reference sample of
interest
to form the following two parameters:
Yd = 8, ¨ (C0 ¨ Clec21nG) "Dilution Index (Yd)"
Xd = "Dimensionless Modulus (Xd)"
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The constants CO, Cl , and C2 are determined by fitting the VGP data S(G*) of
the reference sample to the following equation:
6 = 6-0 _
where Gr* is the complex modulus of this reference sample at its gc =
(0.01c0x).
When an ethylene interpolymer, synthesized with an in-line Ziegler-Natta
catalyst
employing one solution reactor, having a density of 0.920 g/cm3 and a melt
index (MI
or 12) of 1.0 dg/min is taken as a reference sample, the constants are:
CO = 93.43
C-1 = 1.316
C2 = 0.2945
Gr* = 9432 Pa.
The values of these constants can be different if the rheology test protocol
differs from that specified herein.
In the Dilution Index testing protocol, the upper limit on Yd may be about 20,
in
some cases about 15 and is other cases about 13. The lower limit on Yet may be
about ¨30, in some cases ¨25, in other cases ¨20 and in still other cases -15.
In an embodiment of the disclosure, the ethylene interpolymer will have a
Dilution Index, Yd of greater than zero (> 0). In embodiments of the
disclosure, the
ethylene interpolymer will have a Dilution Index, Yd of from 1.0 to 10.0, or
from 3.0 to
7.0, or from 4.0 to 6.5, or from 4.5 to 6.5, or from 4.5 to 6.0, or from 4.5
to 5.5.
Rotomolded Articles
There is a need to improve the balance of properties of rotomolded articles,
including flexible or so called "soft touch" and "soft-touch feel" rotomolded
articles.
The ethylene interpolymer products disclosed herein are well suited to deliver
this
challenging combination of properties.
Typically, for use in a rotational molding process, the ethylene interpolymer
product can be manufactured in powder or pellet form. The rotational molding
process may additionally comprise process steps for manufacturing the ethylene
CA 3057934 2019-10-08
interpolymer product. For rotational molding, powders are preferably used
having a
particle size smaller than or equal to 35 US mesh. The grinding may be done
cryogenically, if necessary. Thereafter, the powder is placed inside a hollow
mold
and then heated within the mold as the mold is rotated. The mold is usually
rotated
biaxially, i.e., rotated about two perpendicular axes simultaneously. The mold
is
typically heated externally (generally with a forced air circulating oven).
The process
steps include tumbling, heating and melting of thermoplastic powder, followed
by
coalescence, fusion or sintering and cooling to remove the molded article.
The ethylene interpolymer product of the present disclosure can be processed
in most commercial rotational molding machines. The time and temperatures used
will depend upon factors including the thickness of the part being rotomolded,
and
one skilled in the art can readily determine suitable processing conditions.
By way of
providing some non-limiting examples, the oven temperature range during the
heating step may be from 400 F to 800 F, or from about 500 F to about 700 F,
or
from about 575 F to about 650 F.
After the heating step the mold is cooled. The part must be cooled enough to
be easily removed from the mold and retain its shape. The mold may be removed
from the oven while continuing to rotate. Cool air is first blown on the mold.
The air
may be an ambient temperature. After the air has started to cool the mold for
a
controlled time period, a water spray may be used. The water cools the mold
more
rapidly. The water used may be at cold tap water temperature, for example it
may be
from about 4 C (40 F) to about 16 C (60 F). After the water cooling step,
another air
cooling step may optionally be used. This may be a short step during which the
equipment dries with heat removed during the evaporation of the water.
The heating and cooling cycle times will depend on the equipment used and
the article being molded. Specific factors include the part thickness in the
mold
material. By way of providing a non-limiting example, conditions for an 1/8
inch thick
part in a steel mold may be, to heat the mold in the oven with air at about
316 C
(600 F) for about 15 minutes; the part may then be cooled in ambient
temperature
forced air for about 8 minutes and then a tap water spray at about 10 C (50
F) for
about 5 minutes; optionally, the part may be cooled in ambient temperature
forced
air for an additional 2 minutes.
During the heating and cooling steps the mold containing the molded article is
preferably continually rotated. Typically this is done along two perpendicular
axes.
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The rate of rotation of the mold about each axis is limited by machine
capability and
the shape of the article being molded. A typical, non-limiting range of
operations
which may be used with the present disclosure is to have the ratio of rotation
of the
major axis to the minor axis of about 1:8 to 10:1 or from about 1:2 to 8:1.
Non-limiting examples of articles which can be made using a rotomolding
process include seat cushions, arm rests, appliance handles, soft touch
playground
equipment, floats, fenders, buoys, furniture, marine buffers, automotive
ducting, bins,
automotive interior parts, children's toys, etc.
The desired physical properties of rotomolded articles depend on the
application of interest. Non-limiting examples of desired properties include:
flexural
modulus (1% and 2% secant modulus); tensile toughness; environmental stress
crack resistance (ESCR); shore hardness; heat deflection temperature (HDT);
VICAT softening point; IZOD impact strength; ARM impact resistance; and color
(whiteness and/or yellowness index).
In an embodiment of the disclosure, an ethylene interpolymer product having
a melt index (12) of up to about 2 g/10 min is used to prepare very large
rotomolded
tanks (e.g. tanks having a volume in excess of 2000 liters). In such an
embodiment,
a very long molding time (in excess of 2 hours) may be used to prepare the
parts.
In an embodiment of the disclosure, an ethylene interpolymer product having
a having a melt index (12) of from about 5 g/10 min to about 8 g/10 min is
used to
prepare smaller rotomolded parts.
In an embodiment of the disclosure, an ethylene interpolymer product having
a having a melt index (12) of from about 2.5 g/10 min to about 8 g/10 min is
used to
prepare smaller rotomolded parts.
As an alternative to rotomolding, the ethylene interpolymer products of the
present disclosure may also be used to manufacture articles by compression
molding or injection molding processes.
Additives and Adjuvants
The ethylene interpolymer products and the manufactured rotomolded articles
described may optionally include, depending on its intended use, additives and
adjuvants. Additives can be added to the ethylene interpolymer products during
an
extrusion or compounding step, but other suitable known methods will be
apparent to
a person skilled in the art. The additives can be added as is or as part of a
separate
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polymer component added during an extrusion or compounding step. Non-limiting
examples of additives and adjuvants include, anti-blocking agents,
antioxidants, heat
stabilizers, slip agents, processing aids, anti-static additives, colorants,
dyes, filler
materials, light stabilizers, heat stabilizers, light absorbers, lubricants,
pigments,
plasticizers, nucleating agents and combinations thereof. Non-limiting
examples of
suitable primary antioxidants include lrganox 1010 [CAS Reg. No. 6683-19-8]
and
Irganox 1076 [CAS Reg. No. 2082-79-3]; both available from BASF Corporation,
Florham Park, NJ, U.S.A. Non-limiting examples of suitable secondary
antioxidants
include lrgafos 168 [CAS Reg. No. 31570-04-4], available from BASF
Corporation,
Florham Park, NJ, U.S.A.; Weston 705 [CAS Reg. No. 939402-02-5], available
from
Addivant, Danbury CT, U.S.A. and; Doverphos lgp-11 [CAS Reg. No. 1227937-46-3]
available form Dover Chemical Corporation, Dover OH, U.S.A. The additives that
can be optionally added are typically added in amount of up to 20 weight
percent
(wt%).
One or more nucleating agent(s) may be introduced into the ethylene
interpolymer product by kneading a mixture of the polymer, usually in powder
or
pellet form, with the nucleating agent, which may be utilized alone or in the
form of a
concentrate containing further additives such as stabilizers, pigments,
antistatics, UV
stabilizers and fillers. It should be a material which is wetted or absorbed
by the
polymer, which is insoluble in the polymer and of melting point higher than
that of the
polymer, and it should be homogeneously dispersible in the polymer melt in as
fine a
form as possible (1 to 10 pm). Compounds known to have a nucleating capacity
for
polyolefins include salts of aliphatic monobasic or dibasic acids or arylalkyl
acids,
such as sodium succinate or aluminum phenylacetate; and alkali metal or
aluminum
salts of aromatic or alicyclic carboxylic acids such as sodium 13-naphthoate.
Another
compound known to have nucleating capacity is sodium benzoate. The
effectiveness
of nucleation may be monitored microscopically by observation of the degree of
reduction in size of the spherulites into which the crystallites are
aggregated.
In embodiments of the disclosure, the ethylene interpolymer products and the
manufactured rotomolded articles described may include additives selected from
the
group comprising antioxidants, phosphites and phosphonites, nitrones,
antacids, UV
light stabilizers, UV absorbers, metal deactivators, dyes, fillers and
reinforcing
agents, nano-scale organic or inorganic materials, antistatic agents, release
agents
such as zinc stearates, and nucleating agents (including nucleators, pigments
or any
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CA 3057934 2019-10-08
other chemicals which may provide a nucleating effect to the polyethylene
composition).
In embodiments of the disclosure, the additives that can be added are added
in an amount of up to 20 weight percent (wt%).
Additives can be added to the ethylene interpolymer products during an
extrusion or compounding step, but other suitable known methods will be
apparent to
a person skilled in the art. The additives can be added as is or as part of a
separate
polymer component added during an extrusion or compounding step.
A more detailed list of additives which may be added to ethylene interpolymer
products of the present disclosure and which are used in rotomolded articles
follows:
Phosphites (e.g. Aryl Monophosphite)
As used herein, the term aryl monophosphite refers to a phosphite stabilizer
which contains: (1) only one phosphorus atom per molecule; and (2) at least
one
aryloxide (which may also be referred to as phenoxide) radical which is bonded
to
the phosphorus.
In an embodiment of the disclosure, aryl monophosphites contain three
aryloxide radicals - for example, tris phenyl phosphite is the simplest member
of this
preferred group of aryl monophosphites.
In another embodiment of the disclosure, aryl monophosphites contain Ci to
Cio alkyl substituents on at least one of the aryloxide groups. These
substituents
may be linear (as in the case of nonyl substituents) or branched (such as
isopropyl
or tertiary butyl substituents).
Non-limiting examples of aryl monophosphites which may be used in
embodiments of the disclosure, include those selected from triphenyl
phosphite;
.. diphenyl alkyl phosphites; phenyl dialkyl phosphites; tris(nonylphenyl)
phosphite
[WESTON 399, available from GE Specialty Chemicals]; tris(2,4-di-tert-
butylphenyl)
phosphite [IRGAFOS 168, available from Ciba Specialty Chemicals Corp.]; and
bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite [IRGAFOS 38, available
from
Ciba Specialty Chemicals Corp.]; and 2,2',2"-nitrilo[triethyltris(3,3'5,5'-
tetra-tert-butyl-
1,1'-biphenyl-2,2'-diy1) phosphite [IRGAFOS 12, available from Ciba Specialty
Chemicals Corp.].
In embodiments of the disclosure, the amount of aryl monophosphite added to
the ethylene interpolymer product is added in from 200 to 2,000 ppm (based on
the
weight of the polymer), or from 300 to 1,500 ppm, or from 400 to 1,000 ppm.
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Phosphites, Phosphonites (e.g. Diphosphite, Diphosphonite)
As used herein, the term diphosphite refers to a phosphite stabilizer which
contains at least two phosphorus atoms per phosphite molecule (and, similarly,
the
term diphosphonite refers to a phosphonite stabilizer which contains at least
two
.. phosphorus atoms per phosphonite molecule).
Non-limiting examples of diphosphites and diphosphonites which may be
used in embodiments of the disclosure include those selected from distearyl
pentaerythritol diphosphite, diisodecyl pentaerythritol diphosphite, bis(2,4
di-tert-
butylphenyl) pentaerythritol diphosphite [ULTRANOX 626, available from GE
Specialty Chemicals]; bis(2,6-di-tert-buty1-4-methylpenyl) pentaerythritol
diphosphite;
bisisodecyloxy-pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-
methylphenyl)
pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl) pentaerythritol
diphosphite,
tetrakis(2,4-di-tert-butylpheny1)4,4'-bipheylene-diphosphonite [IRGAFOS P-EPQ,
available from Ciba] and bis(2,4-dicumylphenyl)pentaerythritol diphosphite
[DOVERPHOS S9228-T or DOVERPHOS S9228-CT] and PEPQ (CAS No 119345-
01-06), which is an example of a commercially available diphosphonite.
In embodiments of the disclosure, the diphosphite and/or diphosphonite
added to the ethylene interpolymer product is added in from 200 ppm to 2,000
ppm
(based on the weight of the polymer), or from 300 to 1,500 ppm, or from 400 to
1,000
ppm.
In an embodiment of the disclosure, the use of diphosphites is preferred over
the use of diphosphonites.
In an embodiment of the disclosure, the most preferred diphosphites are
those available under the trademarks DOVERPHOS S9228-CT and ULTRANOX
626.
Hindered Phenolic Antioxidant
The hindered phenolic antioxidant may be any of the molecules that are
conventionally used as primary antioxidants for the stabilization of
polyolefins.
Suitable examples include 2,6-di-tert-butyl-4-methylphenol; 2-tert-buty1-4,6-
dimethylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,6-di-tert-butyl-4-n-
butylphenol; 2,6-
di-tert-buty1-4isobutylphenol; 2,6-dicyclopenty1-4-methylphenol; 2-(.alpha.-
methylcyclohexyl)-4,6 dimethylphenol; 2,6-di-octadecy1-4-methylphenol; 2,4,6,-
tricyclohexyphenol; and 2,6-di-tert-buty1-4-methoxymethylphenol.
CA 3057934 2019-10-08
Two (non limiting) examples of suitable hindered phenolic antioxidants which
can be used in embodiments of the disclosure, are sold under the trademarks
IRGANOXTM 1010 (CAS Registry number 6683-19-8) and IRGANOXTM 1076 (CAS
Registry number 2082-79-3) by BASF Corporation.
In an embodiment of the disclosure, the amount of hindered phenolic
antioxidant added to the ethylene interpolymer product is added in from 100 to
2000
ppm, or from 400 to 1000 ppm (based on the weight of said thermoplastic
polyethylene product).
Long Term Stabilizers
Plastic parts which are intended for long term use, can in embodiments of the
present disclosure, contain at least one Hindered Amine Light Stabilizer
(HALS).
HALS are well known to those skilled in the art.
When employed, the HALS may in an embodiment of the disclosure be a
commercially available material and may be used in a conventional manner and
in a
conventional amount.
Commercially available HALS which may be used in embodiments of the
disclosure include those sold under the trademarks CHIMASSORBTm 119;
CHIMASSORB 944; CHIMASSORB 2020; TINUVIN TM 622 and TINUVIN 770 from
Ciba Specialty Chemicals Corporation, and CYASORBTM UV 3346, CYASORB UV
3529, CYASORB UV 4801, and CYASORB UV 4802 from Cytec Industries. In some
embodiments of the disclosure, TINUVIN 622 is preferred. In other embodiments
of
the disclosure, the use of mixtures of more than one HALS are also
contemplated.
In embodiments of the disclosure, suitable HALS include those selected from
bis(2,2,6,6-tetramethylpiperidy1)-sebacate; bis-5(1,2,2,6,6-
pentamethylpiperidyI)-
sebacate; n-butyl-3,5-di-tert-buty1-4-hydroxybenzyl malonic acid
bis(1,2,2,6,6,-
pentamethylpiperidyl)ester; condensation product of 1-hydroxyethy1-2,2,6,6-
tetramethy1-4-hydroxy-piperidine and succinic acid; condensation product of
N,N'-
(2,2,6,6-tetramethylpiperidy1)-hexamethylendiamine and 4-tert-octylamino-2,6-
dichloro-1,3,5-s-triazine; tris-(2,2,6,6-tetramethylpiperidyI)-
nitrilotriacetate, tetrakis-
(2,2,6,6-tetramethy1-4-piperidy1)-1,2,3,4butane-tetra-arbonic acid; and
1,1'(1,2-
ethanediy1)-bis-(3,3,5,5-tetramethylpiperazinone).
Hydroxvlamines
It is known to use hydroxylamines and derivatives thereof (including amine
oxides) as additives for polyethylene compositions used to prepare rotomolded
parts,
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as disclosed in for example U.S. Pat. No. 6,444,733 and in embodiments of the
present disclosure, the hydroxylamines and derivatives disclosed in this
patent may
also be suitable for use.
In an embodiment of the disclosure, a useful hydroxylamine for inclusion in
the ethylene interpolymer product can be selected from N,N-
dialkylhydroxylamines, a
commercially available example of which is the N,N-di(alkyl) hydroxylamine
sold as
IRGASTAB 042 (by BASF) and which is reported to be prepared by the direct
oxidation of N,N ¨ di(hydrogenated) tallow amine.
In an embodiment of the disclosure, the ethylene interpolymer product
contains an additive package comprising: a hindered monophosphite; a
diphosphite;
a hindered amine light stabilizer, and at least one additional additive
selected from
the group consisting of a hindered phenol and a hydroxylamine.
Further non-limiting details of the disclosure are provided in the following
examples. The examples are presented for the purposes of illustrating selected
embodiments of this disclosure, it being understood that the examples
presented do
not limit the claims presented.
EXAMPLES
Prior to testing, each specimen was conditioned for at least 24 hours at 23
2 C and 50 10% relative humidity and subsequent testing was conducted at 23
2 C and 50 10% relative humidity. Herein, the term "ASTM conditions" refers
to a
laboratory that is maintained at 23 2 C and 50 10% relative humidity; and
specimens to be tested were conditioned for at least 24 hours in this
laboratory prior
to testing. ASTM refers to the American Society for Testing and Materials.
Density
Ethylene interpolymer product densities were determined using ASTM D792-
13 (November 1, 2013).
Melt Index
Ethylene interpolymer product melt index was determined using ASTM D1238
(August 1, 2013). Melt indexes, 12, 16, 110 and 121 were measured at 190 C,
using
weights of 2.16 kg, 6.48 kg, 10 kg and a 21.6 kg respectively. Herein, the
term
"stress exponent" or its acronym "S.Ex.", is defined by the following
relationship:
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S.Ex.= log (16/12)/log(6480/2160)
wherein 16 and 12 are the melt flow rates measured at 190 C using 6.48 kg and
2.16
kg loads, respectively. In this disclosure, melt index was expressed using the
units
of g/10 minutes or g/10 min or dg/minutes or dg/min; these units are
equivalent.
Gel Permeation Chromatography (GPC)
Ethylene interpolymer product molecular weights, Mn, Mw and Mz, as well the
as the polydispersity (Mw/Mn), were determined using ASTM D6474-12 (Dec. 15,
2012). Ethylene interpolymer product sample solutions (1 to 2 mg/mL) were
prepared by heating the interpolymer in 1,2,4-trichlorobenzene (TCB) and
rotating on
a wheel for 4 hours at 150 C. in an oven. The antioxidant 2,6-di-tert-buty1-4-
methylphenol (BHT) was added to the mixture in order to stabilize the
interpolymer
against oxidative degradation. The BHT concentration was 250 ppm. Sample
solutions were chromatographed at 140 C. on a PL 220 high-temperature
chromatography unit equipped with four Shodex columns (HT803, HT804, HT805
and HT806) using TCB as the mobile phase with a flow rate of 1.0 mL/minute,
with a
differential refractive index (DRI) as the concentration detector. BHT was
added to
the mobile phase at a concentration of 250 ppm to protect GPC columns from
oxidative degradation. The sample injection volume was 200 pL. The GPC raw
data
were processed with the Cirrus GPC software. The GPC columns were calibrated
with narrow distribution polystyrene standards. The polystyrene molecular
weights
were converted to polyethylene molecular weights using the Mark-Houwink
equation,
as described in ASTM D6474-12 (Dec. 15, 2012).
GPC-FTIR
Ethylene copolymer composition (polymer) solutions (2 to 4 mg/mL) were
prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating
on a
wheel for 4 hours at 150 C in an oven. The antioxidant 2,6-di-tert-buty1-4-
methylphenol (BHT) was added to the mixture in order to stabilize the polymer
against oxidative degradation. The BHT concentration was 250 ppm. Sample
solutions were chromatographed at 140 C on a Waters GPC 150C chromatography
unit equipped with four Shodex columns (H1803, H1804, H1805 and H1806) using
TCB as the mobile phase with a flow rate of 1.0 mL/minute, with a FTIR
48
CA 3057934 2019-10-08
spectrometer and a heated FTIR flow through cell coupled with the
chromatography
unit through a heated transfer line as the detection system. BHT was added to
the
mobile phase at a concentration of 250 ppm to protect SEC columns from
oxidative
degradation. The sample injection volume was 300 pL. The raw FTIR spectra were
.. processed with OPUS FTIR software and the polymer concentration and methyl
content were calculated in real time with the Chemometric Software (PLS
technique)
associated with the OPUS. Then the polymer concentration and methyl content
were
acquired and baseline-corrected with the Cirrus GPC software. The SEC columns
were calibrated with narrow distribution polystyrene standards. The
polystyrene
.. molecular weights were converted to polyethylene molecular weights using
the Mark-
Houwink equation, as described in the ASTM standard test method D6474. The
comonomer content was calculated based on the polymer concentration and methyl
content predicted by the PLS technique as described in Paul J. DesLauriers,
Polymer 43, pages 159-170 (2002); herein incorporated by reference.
The GPC-FTIR method measures total methyl content, which includes the
methyl groups located at the ends of each macromolecular chain, i.e. methyl
end
groups. Thus, the raw GPC-FTIR data must be corrected by subtracting the
contribution from methyl end groups. To be more clear, the raw GPC-FTIR data
overestimates the amount of short chain branching (SCB) and this
overestimation
increases as molecular weight (M) decreases. In this disclosure, raw GPC-FTIR
data was corrected using the 2-methyl correction. At a given molecular weight
(M),
the number of methyl end groups (NE) was calculated using the following
equation;
NE = 28000/M, and NE (M dependent) was subtracted from the raw GPC-FTIR data
to produce the SCB/1000C (2-Methyl Corrected) GPC-FTIR data.
Unsaturation Content
The quantity of unsaturated groups, i.e., double bonds, in an ethylene
interpolymer product was determined according to ASTM D3124-98 (vinylidene
unsaturation, published March 2011) and ASTM D6248-98 (vinyl and trans
unsaturation, published July 2012). An ethylene interpolymer sample was: a)
first
subjected to a carbon disulfide extraction to remove additives that may
interfere with
the analysis; b) the sample (pellet, film or granular form) was pressed into a
plaque
of uniform thickness (0.5 mm), and; c) the plaque was analyzed by FTIR.
49
CA 3057934 2019-10-08
Comonomer Content: Fourier Transform Infrared (FTIR) Spectroscopy
The quantity of comonomer in an ethylene copolymer composition was
determined by FTIR and reported as the Short Chain Branching (SCB) content
having dimensions of CH3#/1000C (number of methyl branches per 1000 carbon
atoms). This test was completed according to ASTM D6645-01 (2001), employing a
compression molded polymer plaque and a Thermo-Nicolet 750 Magna-IR
Spectrophotometer. The polymer plaque was prepared using a compression
molding device (Wabash-Genesis Series press) according to ASTM D4703-16 (April
2016).
Composition Distribution Branching Index (CDBI)
The "Composition Distribution Branching Index" or "CDBI" of the disclosed
Examples and Comparative Examples were determined using a crystal-TREF unit
commercially available form Polymer ChAR (Valencia, Spain). The acronym "TREF"
refers to Temperature Rising Elution Fractionation. A sample of ethylene
interpolymer product (80 to 100 mg) was placed in the reactor of the Polymer
ChAR
crystal-TREF unit, the reactor was filled with 35 ml of 1,2,4-trichlorobenzene
(TCB),
heated to 150 C. and held at this temperature for 2 hours to dissolve the
sample. An
aliquot of the TCB solution (1.5 mL) was then loaded into the Polymer ChAR
TREF
column filled with stainless steel beads and the column was equilibrated for
45
minutes at 110 C. The ethylene interpolymer product was then crystallized
from the
TCB solution, in the TREF column, by slowly cooling the column from 110 C. to
30
C. using a cooling rate of 0.09 C. per minute. The TREF column was then
equilibrated at 30 C. for 30 minutes. The crystallized ethylene interpolymer
product
was then eluted from the TREF column by passing pure TCB solvent through the
column at a flow rate of 0.75 mL/minute as the temperature of the column was
slowly
increased from 30 C. to 120 C. using a heating rate of 0.25 C. per minute.
Using
Polymer ChAR software a TREF distribution curve was generated as the ethylene
interpolymer product was eluted from the TREF column, i.e., a TREF
distribution
curve is a plot of the quantity (or intensity) of ethylene interpolymer
eluting from the
column as a function of TREF elution temperature. A CDB150was calculated from
the
TREF distribution curve for each ethylene interpolymer product analyzed. The
CA 3057934 2019-10-08
"CDBI50" is defined as the percent of ethylene interpolymer whose composition
is
within 50% of the median comonomer composition (25% on each side of the median
comonomer composition); it is calculated from the TREF composition
distribution
curve and the normalized cumulative integral of the TREF composition
distribution
curve. Those skilled in the art will understand that a calibration curve is
required to
convert a TREF elution temperature to comonomer content, i.e., the amount of
comonomer in the ethylene interpolymer fraction that elutes at a specific
temperature. The generation of such calibration curves are described in the
prior art,
e.g., Wild, et al., J. Polym. Sci., Part B, Polym. Phys., Vol. 20 (3), pages
441-455:
hereby fully incorporated by reference.
Neutron Activation Analysis (NAA)
Neutron Activation Analysis, hereafter NAA, was used to determine catalyst
residues in ethylene interpolymers and was performed as follows. A radiation
vial
(composed of ultrapure polyethylene, 7 mL internal volume) was filled with an
ethylene interpolymer product sample and the sample weight was recorded. Using
a
pneumatic transfer system the sample was placed inside a SLOWPOKE TM nuclear
reactor (Atomic Energy of Canada Limited, Ottawa, Ontario, Canada) and
irradiated
for 30 to 600 seconds for short half-life elements (e.g., Ti, V, Al, Mg, and
Cl) or 3 to 5
hours for long half-life elements (e.g., Zr, Hf, Cr, Fe and Ni). The average
thermal
neutron flux within the reactor was 5x1011/cm2/s. After irradiation, samples
were
withdrawn from the reactor and aged, allowing the radioactivity to decay;
short half-
life elements were aged for 300 seconds or long half-life elements were aged
for
several days. After aging, the gamma-ray spectrum of the sample was recorded
using a germanium semiconductor gamma-ray detector (Ortec model GEM55185,
Advanced Measurement Technology Inc., Oak Ridge, Tenn., USA) and a
multichannel analyzer (Ortec model DSPEC Pro). The amount of each element in
the sample was calculated from the gamma-ray spectrum and recorded in parts
per
million relative to the total weight of the ethylene interpolymer sample. The
N.A.A.
system was calibrated with Specpure standards (1000 ppm solutions of the
desired
element (greater than 99% pure)). One mL of solutions (elements of interest)
were
pipetted onto a 15 mmx800 mm rectangular paper filter and air dried. The
filter paper
was then placed in a 1.4 mL polyethylene irradiation vial and analyzed by the
N.A.A.
51
CA 3057934 2019-10-08
system. Standards are used to determine the sensitivity of the N.A.A.
procedure (in
counts/pg).
Dilution Index (Yd) Measurements
A series of small amplitude frequency sweep tests were run on each sample
using an Anton Paar MCR501 Rotational Rheometer equipped with the "TruGapTm
Parallel Plate measuring system". A gap of 1.5 mm and a strain amplitude of
10%
were used throughout the tests. The frequency sweeps were from 0.05 to 100
rad/s
at the intervals of seven points per decade. The test temperatures were 1700,
1900
,
210 and 230 C. Master curves at 190 C were constructed for each sample using
the Rheoplus/32 V3.40 software through the Standard TTS (time-temperature
superposition) procedure, with both horizontal and vertical shift enabled.
In some cases, dynamic mechanical analysis was carried out only at 190 C
and the dynamic moduli crossover point occurred at frequencies outside the
experimental range used to generate the data points. The crossover frequency
was
estimated by extrapolating the G' and G" curves, as a function of frequency,
on a
logarithmic scale, using a 33-mode generalized Maxwell model as described in
Rheologica Acta 28.6 (1989): 511-519. For such cases, a sensitivity analysis
was
carried out to estimate the propagated uncertainty in the evaluation of the
dilution
index Yd. The sensitivity analysis consisted in generating 100 random sample
numbers within 10%, 25% and 50% of the extrapolated crossover frequency.
Tensile Properties
The following tensile properties were determined using ASTM D 638:
elongation at yield (%),yield strength (MPa), ultimate elongation (%),
ultimate
strength (MPa) and 1 and 2% secant modulus (MPa).
Flexural Properties
Flexural properties, i.e., 2% flexural secant modulus was determined using
ASTM D790-10 (published in April 2010).
Hexane Extractables
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CA 3057934 2019-10-08
Hexane extractables was determined according to the Code of Federal
Registration 21 CFR 177.1520 Para (c) 3.1 and 3.2; wherein the quantity of
hexane
extractable material in a sample is determined gravimetrically.
Differential Scanning Calorimetry (DSC)
Primary melting peak ( C), melting peak temperatures ( C), heat of fusion
(J/g) and crystallinity (%) was determined using differential scanning
calorimetry
(DSC) as follows: the instrument was first calibrated with indium; after the
calibration, a polymer specimen is equilibrated at 0 C and then the
temperature was
increased to 200 C at a heating rate of 10 C/min; the melt was then kept
isothermally at 200 C for five minutes; the melt was then cooled to 0 C at a
cooling
rate of 10 C/min and kept at 0 C for five minutes; the specimen was then
heated to
200 C at a heating rate of 10 C/min. The DSC Tm, heat of fusion and
crystallinity
are reported from the 2nd heating cycle.
Vicat Softening Point (Temperature)
The Vicat softening point of an ethylene interpolymer product was determined
according to ASTM D1525-07 (published December 2009). This test determines the
temperature at which a specified needle penetration occurs when samples are
subjected to ASTM D1525-07 test conditions, i.e., heating Rate B (120 10 C/hr
and
938 gram load (10 0.2N load).
Dynamic Mechanical Analysis (DMA)
Oscillatory shear measurements under small strain amplitudes were carried
out to obtain linear viscoelastic functions at 190 C under N2 atmosphere, at a
strain
amplitude of 10% and over a frequency range of 0.02-126 rad/s at 5 points per
decade. Frequency sweep experiments were performed with a TA Instruments
DHR3 stress-controlled rheometer using cone-plate geometry with a cone angle
of
5 , a truncation of 137 pm and a diameter of 25 mm. In this experiment a
sinusoidal
strain wave was applied and the stress response was analyzed in terms of
linear
viscoelastic functions. The zero shear rate viscosity (flo) based on the DMA
frequency sweep results was predicted by Ellis model (see R.B. Bird et al.
"Dynamics of Polymer Liquids. Volume 1: Fluid Mechanics" Wiley-lnterscience
53
CA 3057934 2019-10-08
Publications (1987) p.228) or Carreau-Yasuda model (see K. Yasuda (1979) PhD
Thesis, IT Cambridge). The dynamic rheological data were analyzed using the
rheometer software (viz., Rheometrics RHIOS V4.4 or Orchestrator Software) to
determine the melt elastic modulus g(G"=500) at a reference melt viscous
modulus
(G") value of G"=500 Pa. If necessary, the values were obtained by
interpolation
between the available data points using the Rheometrics software. The term
"Storage modulus", G'(co), also known as "elastic modulus", which is a
function of
the applied oscillating frequency, co, is defined as the stress in phase with
the strain
in a sinusoidal deformation divided by the strain; while the term "Viscous
modulus",
G"(w), also known as "loss modulus", which is also a function of the applied
oscillating frequency, w, is defined as the stress 90 degrees out of phase
with the
strain divided by the strain. Both these moduli, and the others linear
viscoelastic,
dynamic rheological parameters, are well known within the skill in the art,
for
example, as discussed by G. Mann in "Oscillatory Rheometry", Chapter 10 of the
book on Rheological Measurement, edited by A. A. Collyer and D. W. Clegg,
Elsevier, 1988.
The evaluation of relative elasticity is based on measurements carried out at
low frequencies, which are most relevant for conditions associated with powder
sintering and densification in rotomolding. The relative elasticity is
evaluated based
on the ratio of G' over G" at a frequency of 0.05 rad/s from DMA frequency
sweep
measurements carried out at 190 C. Data reported in the literature show that
resin
compositions with a high relative elasticity tend to exhibit processing
difficulties in
terms of slow powder densification. Wang and Kontopoulou (2004) reported
adequate rotomoldability for blend compositions that were characterized with a
relative elasticity as high as 0.125. In that study, the effect of plastomer
content on
the rotomoldability of polypropylene was investigated (W.Q. Wang and M.
Kontopoulou (2004) Polymer Engineering and Science, vo. 44, no 9, pp 1662-
1669).
Further analysis of the results published by Wang and Kontopoulou show that
compositions with higher plastomer content exhibited increasing relative
elasticity
(G'/G">0.13) and correspondingly increasing difficulties in achieving full
densification
during rotomolding evaluation.
Melt Strength
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CA 3057934 2019-10-08
The melt strength is measured on Rosand RH-7 capillary rheometer (barrel
diameter = 15mm) with a flat die of 2-mm Diameter, LID ratio 10:1 at 190 C.
Pressure Transducer: 10,000 psi (68.95 MPa). Piston Speed: 5.33 mm/min. Haul-
off Angle: 52 . Haul-off incremental speed: 50 ¨ 80 m/min2 or 65 15 m/min2.
A
polymer melt is extruded through a capillary die under a constant rate and
then the
polymer strand is drawn at an increasing haul-off speed until it ruptures. The
maximum steady value of the force in the plateau region of a force versus time
curve
is defined as the melt strength for the polymer. The melt strength stretch
ratio is
defined as the ratio of the velocity at pulley over the velocity at the exit
of the die.
Shore Hardness
Shore D Hardness was determined according to ASTM D2240 using a Rex D
Durometer or Fowler Shore D Durometer.
Preparation of Ethylene Interpolymer Products
Ethylene interpolymer products were produced in a continuous solution
polymerization pilot plant comprising reactors arranged in a series
configuration.
Methylpentane was used as the process solvent (a commercial blend of
methylpentane isomers). The volume of the first CSTR reactor (R1) was 3.2
gallons
(12 L), the volume of the second CSTR reactor (R2) was 5.8 gallons (22 L) and
the
volume of the tubular reactor (R3) was 4.8 gallons (18 L). Examples of
ethylene
interpolymer products were produced using an R1 pressure from about 14 MPa to
about 18 MPa; R2 was operated at a lower pressure to facilitate continuous
flow
from R1 to R2. R1 and R2 were operated in series mode, wherein the first exit
stream from R1 flows directly into R2. Both CSTR's were agitated to give
conditions
in which the reactor contents were well mixed. The process was operated
continuously by feeding fresh process solvent, ethylene, 1-octene and hydrogen
to
the reactors.
The single site catalyst components used were: component (i),
cyclopentadienyltri(tertiarybutyl)phosphinimine titanium dichloride, (CpRt-
Bu)3PNIffiC12), hereafter PIC-1; component (ii), methylaluminoxane (MA0-07);
component (iii), trityl tetrakis(pentafluoro-phenyl)borate, and; component
(iv), 2,6-di-
tert-buty1-4-ethylphenol. The single site catalyst component solvents used
were
methylpentane for components (ii) and (iv) and xylene for components (i) and
(iii).
CA 3057934 2019-10-08:
The quantity of PIC-1 added to R1, "R1 (i) (ppm)" is shown in Table 1; to be
clear, in
Example Al in Table 1, the solution in R1 contained 0.23 ppm of component (i),
i.e,
PIC-1. The mole ratios of the single site catalyst components employed to
produce
Example Al were: R1 (ii)/(i) mole ratio = 100, i.e. [(MAO-07)/(PIC-1)]; R1
(iv)/(ii)
mole ratio = 0.0, i.e. [(2,6-di-tert-butyl-4-ethylphenol)/(MA0-07)], and; R1
(iii)/(i) mole
ratio = 1.1, i.e. [(trityl tetrakis(pentafluoro-phenyl)borate)/(PIC-1)].
The in-line Ziegler-Natta catalyst formulation was prepared from the following
components: component (v), butyl ethyl magnesium; component (vi), tertiary
butyl
chloride; component (vii), titanium tetrachloride; component (viii), diethyl
aluminum
ethoxide, and; component (ix), triethyl aluminum. Methylpentane was used as
the
catalyst component solvent. The in-line Ziegler-Natta catalyst formulation was
prepared using the following steps. In step one, a solution of
triethylaluminum and
dibutylmagnesium ((triethylaluminum)/(dibutylmagnesium) molar ratio of 20) was
combined with a solution of tertiary butyl chloride and allowed to react for
about 30
seconds (HUT-1); in step two, a solution of titanium tetrachloride was added
to the
mixture formed in step one and allowed to react for about 14 seconds (HUT-2),
and;
in step three, the mixture formed in step two was allowed to reactor for an
additional
3 seconds (HUT-3) prior to injection into R2. The in-line Ziegler-Natta
procatalyst
formulation was injected into R2 using process solvent, the flow rate of the
catalyst
containing solvent was about 49 kg/hr. The in-line Ziegler-Natta catalyst
formulation
was formed in R2 by injecting a solution of diethyl aluminum ethoxide into R2.
The
quantity of titanium tetrachloride "R2 (vii) (ppm)" added to reactor 2 (R2) is
shown in
Table 1A; to be clear in Example Al the solution in R2 contained 6.71 ppm of
TiC14.
Average residence time of the solvent in a reactor is primarily influenced by
the amount of solvent flowing through each reactor and the total amount of
solvent
flowing through the solution process, the following are representative or
typical
values for the examples shown in Table 1A: average reactor residence times
were:
about 61 seconds in R1, about 73 seconds in R2 and about 50 seconds in R3 (the
volume of R3 was about 4.8 gallons (18L)).
Polymerization in the continuous solution polymerization process was
terminated by adding a catalyst deactivator to the third exit stream exiting
the tubular
reactor (R3). The catalyst deactivator used was octanoic acid (caprylic acid),
commercially available from P&G Chemicals, Cincinnati, OH, U.S.A. The catalyst
deactivator was added such that the moles of fatty acid added were 50% of the
total
56
CA 3057934 2019-10-08
molar amount of titanium and aluminum added to the polymerization process; to
be
clear, the moles of octanoic acid added = 0.5 x (moles titanium + moles
aluminum);
this mole ratio was consistently used in all examples.
A two-stage devolatilization process was employed to recover the ethylene
interpolymer product from the process solvent, i.e. two vapor/liquid
separators were
used and the second bottom stream (from the second V/L separator) was passed
through a gear pump/pelletizer combination. DHT-4V (hydrotalcite), supplied by
Kyowa Chemical Industry Co. LTD, Tokyo, Japan was used as a passivator, or
acid
scavenger, in the continuous solution process. A slurry of DHT-4V in process
solvent was added prior to the first V/L separator. The molar amount of DHT-4V
added was about 10-fold higher than the molar amount of chlorides added to the
process; the chlorides added were titanium tetrachloride and tertiary butyl
chloride.
Prior to pelletization the ethylene interpolymer product was stabilized by
adding about 500 ppm of lrganox 1076 (a primary antioxidant) and about 500 ppm
of
lrgafos 168 (a secondary antioxidant), based on weight of the ethylene
interpolymer
product. Antioxidants were dissolved in process solvent and added between the
first
and second V/L separators.
Polymerization process conditions are given in Table 1A.
Table 1A
Polymerization Process Conditions
Process Parameter Example Al
R1 Catalyst PIC-1
R2 Catalyst Ziegler-Natta
R1 (i) (ppm) 0.23
R1 (ii) /(i) mole ratio 100.06
R1 (iv) /(ii) mole ratio 0.04
R1 (iii) /(i) mole ratio 1.10
R2 (vii) (ppm) 6.71
R2 (vi)/(v) mole ratio 1.52
R2 (viii)/(vii) mole ratio 1.35
R2 (ix)/(vii) mole ratio 0.35
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ES R1 45
ESR2 55
ESR3 0
Ethylene concentration
9.90
(wt%) in R1
Ethylene concentration
23.1
(wt%) in R2
Ethylene concentration
12.9
(wt%) overall
Ethylene concentration
NA
(wt%) in R3
0/E 0.63
0SR1 (%) 92
OSR2 (%) 8
0SR3 (%) NA
H2R1 (ppm) 1.2
H2R2 (ppm) 4.9
H2R3 (ppm) NA
Polymer Prod. Rate
78.8
(kg/h)
R1 total solution rate
351.8
(kg/h)
R2 total solution rate
248.2
(kg/h)
Total solution rate
600.0
(kg/h)
R1 inlet temp ( C) 35.0
R2 inlet temp ( C) 35.0
R3 inlet temp ( C) NA
R1 Mean temp ( C) 154.1
R2 Mean temp ( C) 194.3
R3 exit temp ( C) 193.1
58
(CA 3057934 2019-10-08
(0/0) 88.0
QR2 (%) 84.1
QR3 (%) 16.0
QTotal (%) 91.9
Density 0.9130
Melt index, 12 3.8
S.Ex 1.19
MFR 20.5
Mw/Mn 2.6
Mw 73,744
TSR = total flow rate (kg/hr) of solvent + ethylene + octene
ESR1 = % of total ethylene added to first reactor
Ee-R2 =
% of total ethylene added to second reactor
ESR3 = % of total ethylene added to third reactor
0/E = total octene/ethylene weight ratio
SRI = weight% of total octene added to first reactor
OSR2 = weight% of total octene added to second reactor
QFzi = % ethylene in R1 converted to polymer
r,R2 =
% of ethylene in R2 converted to polymer
wow' (%)
70¨ or ethylene converted overall
Polymer production rate (kg/hr) is total polymer produced
MI = melt index, "12" (dg/min)
S.Ex = stress exponent
MFR = 121/12
59
CCA 3057934 2019-10-08
In addition, a computer generated version of an ethylene interpolymer product
is illustrated in Table 16 (using methods substantially as described in U.S.
Pat. No.
9,695,309) in order to estimate the properties of the first and second
ethylene
interpolymers made in each of the first (R1) and the second (R2)
polymerization
reactors. This simulation was based on fundamental kinetic models (with
kinetic
constants specific for each catalyst formulation) as well as the feed and
reactor
conditions presented in Table 1 and used for the production of Example Al. The
simulation was further based on the configuration of the solution pilot plant
described
above which was used to produce the ethylene interpolymer product of Example
Al.
A simulated version of Example Al was synthesized using a single-site catalyst
formulation (PIC-1) in R1 and an in-line Ziegler-Natta catalyst formulation in
R2. As
shown Table 1B, the simulated version of Example Al has a density of 0.9142
g/cm3, a melt index of 2.9 dg/min, a branch frequency of 14.1 (the number of
C6-
branches per 1000 carbon atoms (1-octene comonomer)) and a Mw/Mn of 2.9.
Table 1B also shows the estimated weight fraction, branch frequency, density,
melt
index (12) and molecular weights (Mw, Mn, and Mz) of the first and second
ethylene
interpolymers produced in the two reactors (i.e. in R1 and R2). These are
these two
interpolymers which are combined to produce a simulated version of Example Al
(the ethylene polymer product). Simulated Example Al comprises: a first and
second ethylene interpolymer having a first and second melt index of 2.1
dg/min and
3.6 dg/min, respectively; a first and second density of 0.9064 g/cm3 and
0.9209
g/cm3, respectively; and a first and second Mw/Mn of 2.0 and 3.1,
respectively.
Graphically, a deconvolutjon of the gel permeation chromatograph of Example
Al can be seen in Figure 1B.
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CA 3057934 2019-10-08
TABLE 1B
Computer Generated Simulated Example Al: Single-Site Catalyst Formulation
in R1 (PIC-1) and In-Line Ziepler-Natta Catalyst Formulation in R2
Reactor 2 (R2)
Reactor 1 (R1)
Second Simulated
Simulated Physical Property First Ethylene
Ethylene Example Al
Interpolymer
Interpolymer
Weight percent (%) 45 55 100
Mn 42,086 24,240 29,204
Mw 85,028 75,886 78,229
Mz 129,819 187,596 164,517
Polydispersity (Mw/Mn) 2.0 3.1 2.7
Branch Frequency (C6
16.4 11.5 14.1
Branches per 1000 C)
Density (g/cm3) 0.9064 0.9209 0.9142
Melt Index 12 (dg/min) 2.1 3.6 2.9
The properties of ethylene interpolymer products produced according to the
present disclosure, Example Al and Example 1 are provided in Table 2. Example
Al was manufactured at the pilot plant scale as described above. Example 1 was
manufactured similarly to Example Al but at the commercial scale. Hence,
Example
Al and Example 1 represent two versions of the same targeted ethylene
interpolymer product, with each being manufactured at a different scale of
operation.
Table 2 also includes data for several comparative polyethylene resins,
Examples 2-
8. Example 2 is Surpass RMs539-U, a resin commercially available from the
NOVA
Chemicals Corporation. Example 3 is NOVAPOL TR-0735-U, a resin commercially
available from the NOVA Chemicals Corporation. Example 4 is ENGAGE 8450 a
resin commercially available from Dow Chemical Company. Example 5 is
ENGAGE 8200 a resin commercially available from Dow Chemical Company.
Example 6 is AFFINTY SQ 1503UE a resin commercially available from Dow
Chemical Company. Example 7 is RESIL1TY XUS 58441.00 a resin commercially
61
CA 3057934 2019-10-081
available from Dow Chemical Company. Example 8 is NOVAPOL TR-0338-U, a
resin commercially available from the NOVA Chemicals Corporation.
The properties of compression molded plaques made from an ethylene
interpolymer product (Example 1) or a comparative polyethylene rein (Examples
2-8)
are provided in Table 3.
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TABLE 2
Polymer Properties
Example No. Al 1 2 3 4
Density (g/cm3) 0.9130 0.9115 0.9385 0.9357
0.902
Melt Index 12 (g/10
3.8 4.3 5.1 7.0 3.0
min)
Melt Index 121 (g/10
78 92 114 166 75
min)
Melt Flow Ratio (121/12) 20.5 21.3 22.2
23.8 24.2
Stress Exponent 1.19 1.20
Mn 28,261 23,931 32,164 22,572
37,762
Mw 73,744 67,837 68,495 65,172
66,736
Mz 149,876 129,321 127,387
151,206 . 103,207
Polydispersity Index
2.6 2.8 2.1 2.9 1.8
(Mw/Mn)
CTREF - High
Temperature Elution - 96.2 94.7 96.9
65.3
Peak ( C)
CTREF - CDBI50 - 68.3 68.6 36
89.4
DSC, First melting
103.8 100.0 125.0 125.6 98.0
peak, C
DSC, Second melting
116.0 115.2 None None None
peak, C
DSC, Third melting
122.2 121.8 None None None
peak, C
DSC, Heat of Fusion
113.6 107.7 178.6 168.5 88.0
(J/g)
DSC, Crystallinity ( /0) 39.2 37.1 61.6 58.1
30
GPC-FTIR
Comonomer ca. flat ca. flat reverse normal
normal
Distribution
Comonomer 1-octene 1-octene 1-octene 1-hexene 1-
octene
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CA 3057934 2019-10-081
Comonomer Content
3.7 4 0.9 1.6
(mole%)
Comonomer Content
13.3 14.3 3.7 4.5
(wt%)
Capillary Melt
1.04 0.93 0.76 0.58 1.35
Strength - 190 C (cN)
Capillary Melt
1436 1904 1419 1255
1317
Strength Stretch Ratio
Zero-Shear Viscosity,
2417 1986 1677 1302
4377
o at 190 C (Pa.$)
G'/G" at 0.05 rad/s
0.015 0.015 0.009 0.020
and 190 C
Viscosity Ratio, 10.5 /
1.73 1.70 1.70 1.68 1.83
1150
Internal
0.01 0.01 0.017 0.001 0.006
Unsaturation/100C
Side Chain
0.003 0.004 0.001 0.003
0.003
Unsaturation/100C
Terminal
0.026 0.029 0.009 0.015
0.008
Unsaturation/100C
Hexene extractable
0.71 1.35 0.18 0.59 .68
(%)
Dilution Index, Yd
5.98 5.29 4.28 3.12 -
1.62
(degrees)
TABLE 2 Continued
Polymer Properties
Example No. 5 6 7 8
Density (g/cm3) - 0.8683 0.900 0.887 0.9384
Melt Index 12 (g/10
7.0 6.0 5.0 3.7
min)
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(CA 3057934 2019-10-08
Melt Index 121 (g/10
206 88
min)
Melt Flow Ratio (121/12) 29.3 23.7
Stress Exponent 1.25
Mn 37,650 27,473
Mw 69,231 79,560
Mz 109,198 189,761
Polydispersity Index
1.8 2.9
(Mw/Mn)
CTREF - High
Temperature Elution 96.6
Peak ( C)
CTREF - CDBI5o 49.0
DSC, First melting
61.2 97 119 126.4
peak, C
DSC, Second melting
None None
peak, C
DSC, Third melting
None None
peak, C
DSC, Heat of Fusion
14.8 173.9
(J/g)
DSC, Crystallinity (%) 60.0
GPC-FTIR
Comonomer flat normal
Distribution
Comonomer 1-octene 1-hexene
Comonomer Content
1.2
(mole%)
Comonomer Content
3.6
(wt%)
Capillary Melt
0.66 0.85
Strength - 190 C (cN)
CA 3057934 2019-10-08
Capillary Melt
625 1176
Strength Stretch Ratio
Zero-Shear Viscosity,
1579
rio at 190 C (Pa.$)
GIG" at 0.05 rad/s
0.009 0.024
and 190 C
Viscosity Ratio, /10 5 /
1.96
1150
Internal
0
Unsaturation/100C
Side Chain
0
Unsaturation/100C
Terminal
0.016
Unsaturation/100C
Hexene extractable
0.52
(%)
Dilution Index, Yd
1.39
(degrees)
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CA 3057934 2019-10-08
The data in Table 2 as well as Figures 1-3 show that the ethylene
interpolymer products of Example Al and Example 1 have a relatively narrow
molecular weight distribution (Mw/Mn < 3.0) and a relatively flat or uniform 1-
octene
comonomer incorporation. Without wishing to be bound by any single theory, the
combination of a narrow molecular weight and a flat comonomer incorporation is
thought to enhance powder densification by contributing favorably to the
polymer
rheological characteristics.
The ethylene interpolymer products of Examples Al and 1 have three melting
peaks in a DSC analysis (see Table 2 and Figure 5). In contrast, a single
melting
peak is observed for each of the comparative resins, Examples 2-5 and 8 (see
Table
2 and Figure 5). For the ethylene interpolymer products of Examples Al and 1,
the
three melting peaks occur at temperatures between the melting peaks of the
comparative resins of Examples 2-5 and 8 (which are of higher and lower
density
than the ethylene interpolymer products of Examples Al and 1) and each of the
three melting peaks occurs at a temperature of 100 C or greater. A higher
melting
point is typically considered to be favorable from the standpoint of resin
handling.
The Zero-Shear Viscosity, 110 of the ethylene interpolymer product of
Examples Al and Example 1, is within the range commonly observed for
polyethylene thermoplastics which find application in rotomolded parts (See
Table 2),
and as shown in Figure 6, the viscosity profile of Example 1 is similar to
that of
higher density comparative resins, Examples 2 and 3. However, even though it
has
a broader molecular weight distribution (Mw/Mn), the Zero-Shear Viscosity, Tio
of the
ethylene interpolymer of Example 1 shows a lower dependence on increasing
shear
and frequency in comparison to lower density comparative resin, Example 5.
This
feature may be a consequence of the narrower melt flow ratio (MFR), 121/12
(and
perhaps a relatively low viscosity ratio, Viscosity Ratio, TIO 5 / 1150) for
the ethylene
interpolymer product of Example 1, relative to Example 5.
The melt strength and the melt strength stretch ratio of the ethylene
interpolymer product, Example 1, were found to be relatively high when
contrasted
with those of comparative resins, Examples 2 and 3 (see the data in Table 2).
Example 1 had a melt strength of greater than 0.8 cN, and a melt strength
ratio of
greater than 1500. Without wishing to be bound by any single theory, high melt
strength is considered important in rotomolding applications where the molded
part
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CA 3057934 2019-10-08
has a wall thickness which is small relative to the size of the part itself.
In such
cases, a higher melt strength helps to minimize the occurrence of secondary
melt
flow inside the mold cavity which can result in uneven part thickness.
The relative elasticity, defined as the ratio of G' over G" at a frequency of
0.05
rad/s, reported for both Example Al and Example 1 in Table 2 is less than
0.50,
which is consistent with a relatively low "relative elasticity". Without
wishing to be
bound by theory, a relatively low relative elasticity is considered favorable
for powder
densification during the rotational molding process.
TABLE 3
Compression Molded Plaque Properties
Example No. 1 2 3 4
Density (g/cm3) 0.9115 0.9385 0.9357 0.902
Melt Index 12 (g/10
4.3 5.1 7.0 3.0
min)
Tensile Properties
Elong. at Yield (%) 18 12 11
Elong. at Yield Dev.
1 1 1
(%)
Yield Strength
8.9 20.3 17.9
(MPa)
Yield Strength Dev.
0.1 0.2 0.2
(MPa)
Ultimate Elong. (%) 774 984 653 750
Ultimate Elong.Dev.
6.5 35 42
(%)
Ultimate Strength
32.5 31.3 15.7 22.4
(MPa)
Ultimate Strength
0.7 1.1 1.4
Dev. (MPa)
Sec Mod 1% (MPa) 217 965
Sec Mod 1% (MPa)
4.4 78
Dev.
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Flexural Properties
Flex Secant Mod.
212 817 755 76.3
1% (MPa)
Flex Sec Mod 1%
9 18 28
(MPa) Dev.
Flex Secant Mod.
189 698 641 75.6
2% (MPa)
Flex Sec Mod 2%
6 26 22
(MPa) Dev.
Softening
Temperature
VICAT ( C) 93.7 113.0 84
Hardness
Hardness Shore D 54.0 122.9 60.0 41
TABLE 3 Continued
Compression Molded Plaque Properties
Example No. 5 6 7 8
Density (g/cm3) 0.8683 0.900 0.887 0.9384
Melt Index 12 (g/10
7.0 6.0 5.0 3.7
min)
Tensile Properties
Elong. at Yield (%) 12
Elong. at Yield Dev.
1
(%)
Yield Strength (MPa) 5 19.1
Yield Strength Dev.
0.2
(MPa)
Ultimate Elong. (%) 1100 1200 636
Ultimate Elong.Dev.
22
(%)
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(CA 3057934 2019-10-08
Ultimate Strength
5.7 21 16.3
(MPa)
Ultimate Strength
0.9
Dev. (MPa)
Sec Mod 1% (MPa) 979
Sec Mod 1% (MPa)
149
Dev.
Flexural Properties
Flex Secant Mod. 1%
10.9 46.9 783
(MPa)
Flex Sec Mod 1%
27
(MPa) Dev.
Flex Secant Mod. 2%
10.8 81
(MPa)
Flex Sec Mod 2%
(MPa) Dev.
Softening
Temperature
VICAT ( C) 43.3 82
Hardness
Hardness Shore D 17 40 30.2
CA 3057934 2019-10-08
As can be seen from the data provided in Table 3, an ethylene interpolymer
product of the present disclosure (Example 1) has properties which are useful
for
flexible applications such as for example the manufacture of flexible or "soft
touch"
or "soft touch feel" rotomolded articles.
When made into a compression molded plaque, Example 1 had lower flexural
modulus, lower tensile modulus, higher tensile elongation at yield and a
higher
ultimate tensile strength, when compared to plaques made from comparative
Examples 2, 3 and 8, medium density polyethylene resins which have found
application in rotomolding articles. The much lower flexural secant modulus
(212
MPa at 1%; and 189 MPa at 2%) and tensile secant modulus (217 MPa at 1%) of
Example 1 was particularly noteworthy, and compared more favourably to
commercially available elastomeric and plastomeric resins, Comparative
Examples
4-7.
Without wishing to be bound by theory, the a low tensile and flexural modulus
combined with a high tensile elongation at yield is desirable for the
formation of a
rotomolded part which is flexible enough to deform under stress, but also
resilient
enough to return to its original shape without suffering from permanent
deformation.
The softening temperature (VICAT) for the ethylene interpolymer product of
Example 1 was below 100 C and fell between the values obtained for higher
density
rotomolding grades (Comparative Examples 2 and 3) and lower density
elastomeric
and plastomeric grades (Comparative Examples 4-6). Without wishing to be bound
by any single theory, a higher softening temperature is desirable from the
standpoint
of rein handling, but a lower softening temperature is indicative of improved
haptic
properties which are beneficial for the manufacture of "soft touch" or "soft
touch feel"
articles and end uses.
The Shore D hardness score of 54.0 for the ethylene interpolymer product of
Example 1, also fell between the values obtained for the comparative medium
density (Examples 2 and 3) and low density (Examples 4-7) polyethylene resins.
Ethylene Interpolvmer Product Compounding
A UV (ultra violet) light protective additive was compounded into the ethylene
interpolymer product using a twin screw compounding line. Ethylene
interpolymer
product (97.7 wt %) was tumble blended with an ethylene interpolymer
masterbatch
(2.3 wt %) containing Tinuvin 622 (a UV-light stabilizer available from BASF
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CA 3057934 2019-10-08
Corporation, Florham Park, N.J., U.S.A); this salt and pepper dry blend was
melt
mixed using a Coperion ZSK26MC intermeshing co-rotating twin screw extruder
with
a screw diameter of 26 mm and a length (L) to diameter (D) ratio of 32/1
(LID). The
extruder was operated at about 200 C. at a screw speed of about 200 rpm and
pelletized at a rate of about 20 kg/hr. The compounded ethylene interpolymer
product contain about 1500 ppm of UV-stabilizer. Prior to rotomolding, the
compounded resin was passed through a grinder such that a powder of ethylene
interpolymer product was produced having 35 US mesh size (mesh opening of
0.0197 inch (500 pm)).
Rotomolded Part Preparation
The powdered ethylene interpolymer products of this disclosure are converted
into rotomolded parts employing a rotational molding machine; specifically, a
Rotospeed RS3-160 available from Ferry Industries Inc. (Stow, Ohio, USA). The
Rotospeed has two arms which rotate about a central axis within an enclosed
oven.
The arms are fitted with plates which rotate on an axis that is roughly
perpendicular
to the axis of rotation of the arm. Each arm is fitted with six cast aluminum
molds that
produce a hollow rotomolded part of cubical shape, i.e.: 12.5 inches (31.8
cm)x12.5
inchesx12.5 inches. The arm rotation was set to about 8 revolutions per minute
(rpm) and the plate rotation was set to about 2 rpm. Rotomolded parts having a
nominal thickness of about 0.125 inches (0.32 cm) were produced employing a
standard charge of about 1.85 kg of polyethylene resin in powder form; where
the
powder has a 35 US mesh size (mesh opening of 0.0197 inch (500 pm)). The
temperature within the enclosed oven was maintained at a temperature of 560 F
(293 C). The molds and their contents were heated in the oven for 10, 12 or 14
minutes to ensure that full powder densification was achieved. The molds were
subsequently cooled using air fans for about 30 minutes prior to removing the
part
from the mold. Specimens were collected from the molded parts for density, and
ARM Impact testing and the results are reported in Table 4.
ARM Impact Testing
The ARM impact test was performed in accordance with ASTM D5628, herein
incorporated by reference, at a test temperature of -40 C. This test was
adapted
from the Association of Rotational Molders International, Low Temperature
Impact
72
CA 3057934 2019-10-08
Test, Version 4.0 dated July 2003; herein incorporated by reference. The
purpose of
this test was to determine the impact properties of a rotomolded part. ARM
Impact
test specimens, 5 inchx5 inch (12.7 cmx12.7 cm) were cut from a side wall of
the
cubical rotomolded part. Test specimens were thermally equilibrated in a
refrigerated
testing laboratory maintained at -40 F. 3.5 F (-40 C 2 C) for at least 24
hours
prior to impact testing. The testing technique employed is commonly called the
Bruceton Staircase Method or the Up-and-Down Method. The procedure establishes
the height of a specific dart that will cause 50% of the specimens to fail,
i.e. testing
(dart falling on specimens) was carried out until there was a minimum of 10
passes
and 10 fails. Each failure was characterized as a ductile or a brittle
failure. Ductile
failure was characterized by penetration of the dart though the specimen and
the
impact area was elongated and thinned leaving a hole with stringy fibers at
the point
of failure. Brittle failure was evident when the test specimen cracked, where
the
cracks radiated outwardly from point of failure and the sample showed very
little to
no elongation at the point of failure. The "ARM Ductility %" was calculated as
follows:
100x[(number of ductile failures)/(total number of all failures)].
Samples were impact tested using a drop weight impact tester; impact darts
available consisted of 10 lb (4.54 kg), 15 lb (6.80 kg), 20 lb (9.07 kg) or 30
lb (13.6
kg) darts. All impact darts had a rounded dart tip having a diameter of 1.0
0.005 inch
(2.54 cm), the dart tip transitioned into a lower cylindrical shaft (1.0 inch
diameter),
the length of the lower cylindrical shaft (to dart tip) was 4.5 inch (11.4
cm). Impact
dart included an upper cylindrical shaft having a diameter of 2.0 inch (5.08
cm), the
length of the upper cylinder shaft varied depending on the desired weight of
the dart,
e.g. 10.5 inch (26.7 cm) or 16.5 inch (41.9 cm) for the 10 lb or 20 lb dart,
respectively. Preferably a dart weight is selected such that the drop height
is
between 2.5 ft and 7.5 ft (0.8 m to 2.3 m). Test specimens were oriented in
the
impact tester such that the falling dart impacted the surface of the part that
was in
contact with the mold (when molded). If the sample did not fail at a given
height and
weight, either the height or weight was increased incrementally until part
failure
occurred. Once failure occurred, the height or weight is decreased by the same
increment and the process is repeated. The "ARM Mean Failure Energy (ft=lbs)"
was
calculated by multiplying the drop height (ft) by the nominal dart weight
(lbs). After
impact, both the upper and lower surface of the specimen were inspected for
failure.
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CA 3057934 2019-10-08
For the ethylene interpolymer products disclosed herein, a ductile failure was
desired
failure mode.
74
CA 3057934 2019-10-08
0
01
TABLE 4
0
ARM Impact Properties of Rotomolded Parts (0.125 inches thickness)
Example No. 1 2
3
co Oven Residence
12 14 10 12 14 10 12 14
Time
ARM Impact
at ¨40 C, ARM
47.8 39.4 43.3 27.7
40.7 48.8 29.7 25.8 46.8
Mean Failure
Energy (ft.lb)
Ductility (%) 100 100 100 55 100
100 56 67 82
Peak Internal Air
160.6 184.4 206.7 171.7
200.0 217.8 179.4 206.7 221.7
Temperature ( C)
Density (g/cm3) 0.8963 0.8987 0.9085 0.9329
0.9402 0.9406 0.9246 0.9353 0.9369
5
The data in Table 4 show that the ethylene interpolymer product of Example 1
has good ARM impact performance properties with a high mean failure energy (of
from 39.4 to 47.8 ft.lb) and a high ductility failure rate (with 100% of the
failures
occurring being ductile failures rather than brittle failures). In contrast,
comparative
Examples 2 and 3 showed an increased propensity for brittle failures and had a
lower average mean failure energy when considered over the three different
oven
residence times (10min, 12min and 14min).
In addition, the ethylene interpolymer of Example 1 could be rotomolded at a
lower peak internal air temperature relative to comparative Examples 2 and 3.
This
is consistent with the lower melting point temperatures observed for the
ethylene
interpolymer product of Example 1 in the differential scanning colorimetry
analysis
relative to Examples 2 and 3 (see the data in Tables 2 and 4). This may afford
some
advantages with respect to energy utilization when rotomolding a part using
the
ethylene interpolymer products described in the present disclosure.
Non-limiting embodiments of the present disclosure include the following:
Embodiment A. A rotomolded article prepared from an ethylene interpolymer
product having a melt index, 12 of from 2.5 to 8.0 g/10min, and a density of
from
0.905 to 0.920 g/cm3; wherein said ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(PI)b(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; and Q is independently selected from the group consisting of a
hydrogen
atom, a halogen atom, a Ci-io hydrocarbyl radical, a Ci_io alkoxy radical and
a C5-10
aryl oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals
may be unsubstituted or further substituted by a halogen atom, a Ci_18 alkyl
radical, a
C1_8 alkoxy radical, a C8_10 aryl or aryloxy radical, an amido radical which
is
unsubstituted or substituted by up to two C1_8 alkyl radicals or a phosphido
radical
76
CA 3057934 2019-10-08
which is unsubstituted or substituted by up to two C1-8 alkyl radicals;
wherein a is 1; b
is 1; n is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M,
and;
wherein said second ethylene interpolymer is produced using a first Ziegler-
Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first Ziegler-Natta catalyst formulation or a second Ziegler-Natta
catalyst
formulation, and;
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0.
Embodiment B. The rotomolded article according to Embodiment A wherein
the ethylene interpolymer product has a density of from 0.905 to 0.914 g/cm3.
Embodiment C. The rotomolded article according to Embodiment A or B
wherein the ethylene interpolymer product has a density of from 0.910 to 0.912
g/cm3.
Embodiment D. The rotomolded article according to Embodiment A, B or C
wherein the ethylene interpolymer product has a melt index, 12 of from 2.5 to
6.0
g/10min.
Embodiment E. The rotomolded article according to Embodiment A, B, C, or
D wherein the ethylene interpolymer product has a melt index, 12 of from 2.5
to 4.5
g/10min.
Embodiment F. The rotomolded article according to claim Embodiment A, B,
C, D or E wherein the ethylene interpolymer product has a molecular weight
distribution, Mw/Mn of less than 4Ø
Embodiment G. The rotomolded article according to Embodiment A, B, C, D,
E, or F wherein the ethylene interpolymer product has a composition
distribution
breadth index, CDBI50 of at least 65%.
Embodiment H. The rotomolded article according to Embodiment A, B, C, D,
E, F, or G wherein the ethylene interpolymer product has three melting peaks
in a
differential scanning calorimetry (DSC) analysis.
Embodiment I. The rotomolded article according to H wherein each of the
melting peaks have a minimum at a temperature of 100 C or greater.
Embodiment J. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, or I wherein the ethylene interpolymer product has a Dilution
Index, Yd, of
from 4.5 to 6.5.
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CA 3057934 2019-10-08
Embodiment K. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, or J wherein the ethylene interpolymer product is made using a
solution
polymerization process.
Embodiment L. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, or K wherein the ethylene interpolymer product comprises
ethylene
and 1-octene.
Embodiment M. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, 1, J, K, or L wherein the ethylene interpolymer product has a
flexural
secant modulus at 1%, of less than 300 MPa.
Embodiment N. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L or M wherein the ethylene interpolymer product has a
tensile
secant modulus at 1%, of less than 300 MPa.
Embodiment 0. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, or N wherein the ethylene interpolymer product has
a tensile
elongation at yield of greater than 14%.
Embodiment P. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, 1, J, K, L, M, N, or 0 wherein the ethylene interpolymer product
has a
VIACAT softening temperature of below 100 C.
Embodiment Q. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, N, 0, or P wherein the ethylene interpolymer
product has a
Shore D hardness score of less than 60.
Embodiment R. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, N, 0, P, or Q wherein the ethylene interpolymer
product has
a zero shear viscosity, go at 190 C of from 1000 to 5000 Pa.s.
Embodiment S. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, N, 0, P, Q, or R wherein the ethylene interpolymer
product
has a relative elasticity, defined as the ratio of G' over G" at a frequency
of 0.05
rad/s, of less than 0.50.
Embodiment T. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, 1, J, K, L, M, N, 0, P, Q, R, or S wherein the ethylene
interpolymer
product has a melt strength of at least 0.8 cN.
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CA 3057934 2019-10-08
Embodiment U. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, N, 0, P, Q, R, S, or T wherein the ethylene
interpolymer
product has a melt strength stretch ratio of greater than 1400.
Embodiment V. The rotomolded article according to Embodiment A, B, C, D,
E, F, G, H, I, J, K, L, M, N, 0, P, Q, R, S, T or U wherein the ethylene
interpolymer
product has 0.024 terminal vinyl unsaturations per 100 carbon atoms.
Embodiment W. A process for forming a rotomolded article, the process
comprising:
(a) preparing an ethylene interpolymer product having a melt index, 12 of from
2.5 to 8.0 g/10min, and a density of from 0.905 to 0.920 g/cm3; wherein said
ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(III) optionally a third ethylene interpolymer;
wherein said first ethylene interpolymer is produced using a single site
catalyst formulation comprising a component (i) defined by the formula
(LA)aM(PI)b(Q)n
wherein LA is selected from the group consisting of unsubstituted
cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl,
substituted
indenyl, unsubstituted fluorenyl and substituted fluorenyl; M is a metal
selected from
the group consisting of titanium, hafnium and zirconium; PI is a phosphinimine
ligand; and Q is independently selected from the group consisting of a
hydrogen
atom, a halogen atom, a Ci-io hydrocarbyl radical, a Ci-io alkoxy radical and
a C5-10
aryl oxide radical; wherein each of said hydrocarbyl, alkoxy, and aryl oxide
radicals
may be unsubstituted or further substituted by a halogen atom, a C1-18 alkyl
radical, a
C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amido radical which
is
unsubstituted or substituted by up to two C1-8 alkyl radicals or a phosphido
radical
which is unsubstituted or substituted by up to two C1-8 alkyl radicals;
wherein a is 1; b
is 1; n is 1 or 2; and (a+b+n) is equivalent to the valence of the metal M,
and;
wherein said second ethylene interpolymer is produced using a first Ziegler-
Natta catalyst formulation;
wherein said third ethylene interpolymer, when present, is produced using
said first Ziegler-Natta catalyst formulation or a second Ziegler-Natta
catalyst
formulation, and;
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CA 3057934 2019-10-08
wherein said ethylene interpolymer product has a Dilution Index, Yd, greater
than 0; and
(b) rotomolding the ethylene interpolymer product to form a rotomolded
article.
Embodiment X. The process of Embodiment W wherein the ethylene
interpolymer product has a density of from 0.905 to 0.914 g/cm3.
Embodiment Y. A rotomolded article prepared from an ethylene interpolymer
product having a melt index, 12 of from 2.5 to 8.0 g/10min, and a density of
from
0.905 to 0.920 g/cm3; wherein said ethylene interpolymer product comprises:
(I) a first ethylene interpolymer;
(II) a second ethylene interpolymer, and;
(111) optionally a third ethylene interpolymer;
wherein said ethylene interpolymer product has a Dilution Index, Yd, of from
4.5 to 6Ø
Embodiment Z. The rotomolded article of Embodiment Y wherein the
ethylene interpolymer product has a density of from 0.905 to 0.914 g/cm3.
Embodiment AA. The rotomolded article of Embodiment Y wherein the
ethylene interpolymer product has a density of from 0.910 to 0.912 g/cm3.
CA 3057934 2019-10-08
