Note: Descriptions are shown in the official language in which they were submitted.
~'~ ~''m~Qd~ P~~'lYTS94I10621
GAS PHASE PLYEIZATIGLFI S
This invention relates to a gas phase ffuidized bed process for
producing olefin polymers, particularly ethylene polymers, having improved
processability. These polymers include olefin polymers having low
susceptibility to melt fracture, even under high shear stress conditions.
The discovery of the fluidized bed process for the production of linear
olefin polymers provided a means for producing these diverse and widely used
polymers with a drastic reduction in capital investment and a dramatic
reduction in energy requirements as compared to then conventional
processes.
To be commercially useful in a gas phase process, such as the fluid bed
processes of U.S. Pat. Nos. 3,709,853; 4,003,712 and 4,011,382; Canadian
Pat. No. 991,798 and Selgian Pat. No. 839,380, the catalyst employed must be
a highly active catalyst. Typically, levels of productivity reach from 50,000
to
1,000,000 pounds of polymer or more per pound of primary metal in the
catalyst. High productivity in the gas phase processes is desired to avoid the
expense of catalyst residue removal procedures. Thus, the catalyst residue in
th~~ polymer must be small enough that it can be left in the polymer without
causing any undue problems to either the resin manufacturer, or to a party
fabricating articles from the resin, or to an ultimate user of such fabricated
articles. lNhere a high activity catalyst is successfully used in such fluid
bed
processes, the transition metal content of the resin is on the order of <_ 20
parts
per million (ppm) of primary metal at a productivity level of _> 50,000 pounds
of
polymer per pound of metal. Lovv catalyst residue contents are also important
in heterogeneous catalysts comprising chlorine containing materials such as
the titanium, magnesium and/or aluminum chloride complexes used in some
so-called Ziegler or Ziegler-Natta type catalysts. lJse of these heterogeneous
catalysts results in a polymerization reaction product which is a complex
mixture of polymers, ~rith a relatively wide distribution of molecular
weights.
This wide distribution of molecular weights has an effect (generally
detrimental) on the physical properties of the polymeric materials, e.g.
decreased tensile strength, dart impact.
_1_
CA 02171103 2004-11-04
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The molecular weight distribution (MWD), or poiydispersity, is a known
variable in polymers which is described as the ratio of weight average
molecular weight (Mw) to number average molecular weight (Mn) (i.e., Mw/Mn),
parameters which can be determined directly, for example by gel permeation
chromatography techniques. The I ~ p/12 ratio, as described in ASTM D-1238,
can be an indicator of the MWD in conventional heterogeneous ethylene
polymers. The I~p/12 ratio is also an indicator of the-shear sensitivity and
processibility for ethylene polymers. Low density polyethylenes (LDPE)
typically have a higher 11 p/12 ratio than linear low density polyethylenes
(LLDPE) or ultra low density linear polyethylenes (ULDPE) and are easier to
melt process in fabrication equipment ~at comparable 12 values.
Ethylene polymers having a narrow MWD and homogeneous
comonomer distribution are known. These polymers can be produced using
homogeneous 'single site" catalysts, such as metallocene or vanadium
catalysts. Whsle the physical properties of these polymers are generally
superior to heterogeneous polymers, they are often difficult to process with
conventional melt fabrication equipment. The problems are manifested, for
example, in their lack of ability to sustain a bubble it a blow's film
process, and
by a 'sag' when evaluated in blow molding processes. In addition, the melt
fracture surface properties of these polymers are often unacceptable at high
extrusion rates, a feature that makes them less desirable for use in equipment
operating at current high speed extrusion (i:e., production) rates. Extruders
often exhibit increased power consumption due to the low shear sensitivity of
these polymers.
Use of the catalyst systems described in U.S. Patent
Nos. 5,374,696 and 5,453,410, results in the production
of unique polymers having the properties as taught in
U.S. Patent Nos. 5,272,236 and 5,278,272. These polymers
are substantially linear olefin polymers which are
characterized as having a critical shear rate at the onset
of surface melt fracture of at least 50 percent greater than
the critical shear rate at the onset of
-2-
W~ 9~J07942 PC'd'/i1S94I10621
surface melt fracture of a linear olefin polymer having about the same L2 and
Mw/n.
There is a need for a gas phase olefin polymerization catalyst that can
be used more efficiently and effectively to polymerize or copolymerize
ethylene
with higher alpha-olefins, e.g. alpha-olefins having 3 to 20 carbon atoms. In
practice, the commercial copolymers are made rising monomers having only 3
to carbon atoms (i.e., propylene, 1-butane, 1-hexane, 1-octane and 4-methyl-
1-pentane) because of the low rate of reactivity and incorporation of the
alpha
olefins with larger carbon chains and, for gas phase processes, because of the
lower concentration possible in the reactor for alpha-olefins with larger
carbon
chains. The traditional Ziegler catalysts are not particularly efficient or
efv~ective in incorporating the higher alpha-olefin comonomers into the
polymer.
The rate of reaction for the ethylene monomer is much greater than the rate of
reaction for the higher alpha-olefin monomers in the copolymerization reaction
using traditional multi-site Ziegler catalysts. Accordingly, due to the lower
reaction rate of incorporating the longer chain comonomer into the growing
polymer chain, the copolymer fractions containing the higher alpha-olefin
comonomers are generally the lower molecular weight fraction having limited
desirable physical properties. These factors also contribute to polymer
particles sticking together or agglomerating in the gas phase process.
Even in the most current olefin copolymerization systems, there is still a
need for a gas phase olefin polymerization catalyst which is able to
incorporate
efficiently larger amounts of higher alpha-olefins into a copolymer chain and
give a polymeric product which has a narrow molecular weight distribution and
is more homogeneous with respect to comonomer distribution than otherwise
would be achieved using a Ziegler catalyst under comparable conditions. The
properties and advantages of linear homogeneous copolymers are described
in IJ.S. Patent 3,fi45,992.
Canich et al. teach in IJ.S. Patent 5,057,4I'5, U.S. Patent 5,026,798,
and
LJ. S. Patent 5,096,867 a supported catalyst system which includes an inert
support material, a Group IV B metal component and an alumoxane
component for use in the production of high molecular weight poiyolefins.
-3-
~'~ 9~1~79~2 ~Wf'lli(J~9~/~~~~g
a: er
.. , J t.
Thorn is also a need for a gas phase process to produce more
homogeneous narrow molecular weight distribution pofyolefins ~I~~ of ~.5-
2.5)9 that have improved processability such as provided by substantially
linear
olefin polymers.
A fluidized bed gas phase process for the production of an ethylene
Another aspect of this invention is a process for in situ blending of
polymers oomprising continuously contacting, under polymerization condBt~onso
a mixture of ethylene and at feast one or more ~,-olefin or diolefin in at
least
two fluidized bed reactors connected in series, with a catalyst with the
polyrneri~ation conditions being such that an ethylene copolyr~aer having a
higher melt index is formed in at least one reactor and an ethylene copolymer
having a lower rraelt index is formed in at least one other reactor with the
provisos that:
(a) in a reactor in ~rhich the lower melt index copolymer is made:
(1 ) said alpha-olefin or diolefin is present in a ratio of about ~.~ t '~o
about 3.5 total moles of alpha-olefin and diofefin per mole of ethylene; and
~'~ 95107942 PC'1'//1JS94I10621
(2) hydrogen is present in a ratio of about 0 to about 0.3 mole of
hydrogen per mole of ethylene;
(b) in a reactor in which higher melt index copolymer is made:
(1 ) said alpha-olefin or diolefin is present in a ratio of about 0.005 to
about 3.0 total moles of alpha-olefin and diolefir~ per mole of ethylene; and
(2) hydrogen is present in a ratio of about 0.05 to about 2 moles of
hydrogen per mole of ethylene,
(c) the mixture of catalyst and ethylene copolymer formed in one reactor in
the series is transferred to an immediately succE~eding reactor in the series.
(d) the catalyst system comprises a constrained geometry catalyst and
optionally, another catalyst.
(e) catalyst may be optionally added to each reactor in the series9 provided
that catalyst is added to at least the first reactor in the series;
Yet another aspect of this invention is the process for in situ blending of
polymers comprising continuously contacting, under polymerization conditions,
a mixture of ethylene and at least one ~,-olefin andlor diolefin in at least
two
fluidized bed reactors connected in parallel, with a catalyst with the
polymerization conditions being such that an ethylene copolymer having a
higher melt index is formed in at least one reactor and an ethylene copolymer
having a lower melt index is formed in at least one other reactor with the
provisos that:
(a) in a reactor in which the lower melt index copolymer is made:
(1 ) said alpha-olefin and/or diolefin is present in a ratio of about 0.01 to
ak~out 3.5 total moles of alpha-olefin or diolefin per mole of ethylene; and
_5_
CA 021171103 2004-11-04
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(2) hydrogen is present in a ratio of about 0 to
about 0.3 mole of hydrogen per mole of ethylene;
(b) in a reactor in which higher melt index
copolymer is made:
(1) said alpha-olefin or diolefin is present in a
ratio of about 0.005 to about 3.0 total moles of alpha-
olefin and diolefin per mole of ethylene; and
(2) hydrogen is present in a ratio of about 0.05
to about 2 moles of hydrogen per mole of ethylene,
(c) the catalyst system comprises a constrained
geometry catalyst and optionally, another catalyst.
In all embodiments of the invention, the
constrained geometry catalyst is used in at least one of the
reactors.
An advantage of this invention is that at least
one constrained geometry catalyst can be used alone or in
conjunction with at least one other catalyst in reactors
operated in series or parallel.
Yet another advantage is that due to the ability
of supported constrained geometry catalysts to incorporate
efficiently longer chain higher alpha-olefin comonomers into
a polymer, the range of copolymer densities which can be
made in a conventional gas phase reactor without having to
condense the recycle stream is dramatically increased.
In one aspect, the invention provides a fluidized
bed gas phase process for the production of an ethylene
polymer comprising reacting by contacting under
polymerization conditions ethylene or ethylene and at least
one of a copolymerizable alpha-olefin or diolefin in the
-6-
CA 02171103 2004-11-04
74296-4
presence of a catalyst characterized by an absence of an
activating amount of alumoxane, comprising: A) 1) a metal
complex corresponding to the general formula:
~Z\
L \Y
'M'
~X~)q ~n
or dimers thereof, wherein: M is a Group 4 metal in the +3
or +4 formal oxidation state; L is a group containing a
cyclic, delocalized, aromatic, anionic, ~ system and the
inertly substituted derivatives thereof through which the L
group is bound to M, and which L group is also bound to Z,
said L group containing up to 60 non-hydrogen atoms; Z is a
moiety covalently bound to both L and Y, comprising boron,
or a member of Group 14 of the Periodic Table of the
Elements, said moiety having up to 60 non-hydrogen atoms; Y
is a moiety comprising nitrogen, phosphorus, sulfur or
oxygen through which Y is covalently bound to both Z and M,
said moiety having up to 25 non-hydrogen atoms; X'
independently each occurrence is a Lewis base containing up
to 40 non-hydrogen atoms; X independently each occurrence is
a monovalent anionic moiety having up to 20 non-hydrogen
atoms, provided however that neither X is an aromatic group
that is ~-bonded to M, optionally, two X groups may be
covalently bound together forming a divalent dianionic
moiety having both valences bound to M, or further
optionally one or more X and one X' group may be bonded
together thereby forming a moiety that is both covalently
bound to M and coordinated thereto by means of Lewis base
functionality; q is a number from 0 to 1; and n is 1 or 2
depending on the formal oxidation state of M; 2) an
-6a-
CA 02171103 2004-11-04
74296-4
activating cocatalyst selected from the group consisting of
(i) C1-C3o hydrocarbyl substituted boranes and halogenated
derivatives thereof, and (ii) borates of the general
formula:
[L*-H]+[BQ4]
wherein: L* is a neutral Lewis base; [L*-H]+ is a Bronsted
acid; B is boron in a valence state of 3; and Q is a
hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-,
fluorinated hydrocarbyloxy-, or fluorinated
silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with
the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is
substantially free of adsorbed moisture or surface
hydroxyls; or B) the complex of the above formula is
electrochemically oxidized to an active catalyst under
electrolysis conditions in the presence of a supporting
electrolyte comprising a noncoordinating, inert anion.
In a further specific aspect, the invention
provides a fluidized bed gas phase process for the
production of an ethylene polymer comprising reacting by
contacting under polymerization conditions ethylene or
ethylene and at least one of a copolymerizable alpha-olefin
or diolefin in the presence of a catalyst characterized by
an absence of an activating amount of alumoxane, comprising:
A) 1) a metal complex corresponding to the general formula:
R'
Y
R~ (I)
~~'~n
R'
-6b-
CA 02'171103 2004-11-04
74296-4
wherein: R' each occurrence is independently selected from
hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and
combinations thereof, said R' having up to 20 non-hydrogen
atoms, and optionally, two R' groups (where R' is not
hydrogen, halo or cyano) together form a divalent derivative
thereof connected to adjacent positions of the
cyclopentadienyl ring to form a fused ring structure; Y is
-0-, -S-, -NR*-, -PR*-; Z is SiR*2, CR*2, SiR*2SiR*2,
CR*zCR*2, CR*=CR*, CR*zSiR*2, or GeR*2; wherein: R* each
occurrence is independently hydrogen, or a member selected
from the group consisting of hydrocarbyl, silyl, halogenated
alkyl, halogenated aryl, and combinations thereof, said R*
having up to 20 non-hydrogen atoms, and optionally, two R*
groups from Z (when R* is not hydrogen), or an R* group from
Z and an R* group from Y form a ring system; M is titanium
or zirconium in the +3 or +4 formal oxidation state; X is
chloro, hydrocarbyl, hydrocarbyloxy, silyl or
N,N-dialkylamino substituted hydrocarbyl group; and n is 1
or 2; 2) an activating cocatalyst selected from the group
consisting of (i) C1-C3o hydrocarbyl substituted boranes and
halogenated derivatives thereof, and (ii) borates of the
general formula:
[L*-H] + [BQ4]
wherein: L* is a neutral Lewis base; [L*-H]+ is a Bronsted
acid; B is boron in a valence state of 3; and Q is a
hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-,
fluorinated hydrocarbyloxy-, or fluorinated
silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with
the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is
g~,~hgt~_n_ti_al l_ 1r frees pf arlcprbarl rrtni_gtpre pr cprfurc
hydroxyls; or B) the complex of formula (I) is
electrochemically oxidized to an active catalyst under
-6c-
CA 02171103 2004-11-04
74296-4
electrolysis conditions in the presence of a supporting
electrolyte comprising a noncoordinating, inert anion.
Figure 1 graphically displays the structural
characteristics of a traditional heterogeneous Ziegler
polymerized LLDPE copolymer, a highly branched high pressure
free radical LDPE, a homogeneously branched linear
copolymer, and a substantially linear ethylene alpha-olefin
copolymer.
The Ethylene Copolymers
All reference to the Periodic Table of the
Elements herein shall refer to the Periodic Table of
the Elements, published and copyrighted by CRC Press,
Inc., 1989. Also, any reference to a Group or Groups shall
be to the Group or
-6d-
W~ 95/07942 PC'T/iJS94110621
Groups as reflected in this Periodic Table of the Elements using the IlJPAC
system for numbering Groups.
Monomers usefully polymerized according to the present invention
include, for example, ethylenically unsaturated monomers, conjugated or
nonconjugated dienes, polyenes, etc. Preferred monomers include the C2-C10
~-olefins especially ethylene, propane, isobutylene, 1-butane, 1-hexane, 4-
methyl-1-pentane, and 1-octane. ~ther preferred monomers include styrene,
halo- or alkyl substituted styrenes, tetrafluoroethylene,
vinylbenzocyclobutene,
1,4-hexadiene, 1,5-hexadiene, 1,7-octadieneo 4-vinylcyclohexene, and
vinylcyclohexane, 2,5-norbornadiene, ethylidenenorbornene, 1,3-pentadiene,
1,4-pentadiene, 1,3-butadiene, isoprene and nahhthenics (e.g., cyclopentene,
cyclohexene and cyclooctene).
Throughout this disclosure, °'melt index" cr "12°' is
measured in
accordance with ASTM D-1238 (190°C/2.16 kg)9 .'110" is measured in
accordance with ASTM D-1238 (190°C/10 kg). I=or linear polyolefins,
especially linear polyethylene, it is well known that as Mw/Mn increases,
110/12
also increases. Vllith the ethylene or ethylene/~,~~olefin or diene
substantially
iir~~ear olefin polymers that can be made by this invention, the 110/12 may be
increased without increasing Mw/Mn. The melt index for the ethylene or
ethyfene/~,-olefin substantially linear olefin polymers used herein is
generally
from about 0.01 grams/10 minutes (g/10 min) to about 1000 g/10 min,
preferably from about 0.01 g/10 min to about 100 g/10 min, and especially from
about 0.01 g/10 min to about 10 g/10 min.
_7-
CA 02171103 2004-11-04
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The copolymers have a 110/12 melt flow ratio of about >_ 6 to _< 18, and
preferably of about ? 7 to <_ 14.
The whole interpolymer product samples and the individual interpolymer
samples are analyzed by gel permeation chromatography (GPC) on a Waters
150C high temperature chromatographic unit equipped with three mixed
porosity bed columns (available from Polymer Laboratories); operating at a
system temperature of 140C. The solvent is 1,2,4-trichlorobenzene, from which
0.3 percent by weight solutions of the samples are prepared for injection. The
flow rate is 1.0 milliliters/minute and the injection size is 200 microliters.
The molecular weight determination is deduced by using narrow
molecular weight. distribution polystyrene standards (from Polymer
Laboratories) in conjunction with their elution volumes. The equivalent
polyethylene molecular weights are determined by using appropriate Mark-
Houwink coefficients for polyethylene and polystyrene (as described by
Williams and Word in Journal of Po_lyrmer Science, Pol3rmer Letters, Vol. 6,
(621 ) 1968) to derive the following equation:
Mpolyethylene = a * (Mpolystyrene)b.
In this equation, a = 0.4316 and b = 1Ø Weight average molecular weight,
Mw, is calculated in the usual manner according to the following formula: Mw =
E wi* Mi, where w1 and Mi are the weight fraction and molecular weight,
respectively, of the ith fraction eluting from the GPC column.
The molecular weight distribution (Mw/Mn) for the ethylene polymers of
this invention is generally less than about 5, preferably from about 1.5 to
about
2.6, and especially from about 1.7 to about 2.3.
The density of the polymers in the present invention is measured in
accordance with ASTM D-792 and is generally from about 0.85 g/cm3 to about
0.96 g/cm3, preferably from about 0.865 g/cm3 to about 0.96 g/cm3. The
density of the copolymer, at a given melt index level for the copolymer, is
primarily regulated by the amount of the comonomer which is copolymerized
With tl~e et hylene. lil tile abS2f7i,e Of ti i~ LW 1 ivi WnTicr , ii i2 Bti
iy~2ii2 wOUid
_g.
~ 95107942 ~~ThLTS94I1062I
Tl~e term °'linear" as used herein means that the ethylene polymer
does not
have long chain branching. That is, the polymer chains comprising the bulk
linear ethylene polymer have an absence of long chain branching, as for
em~ample the traditional linear low density polyethylene polymers or linear
high
density polyethylene polymers made using Ziegler polymerization processes
(e.g., l9SP 4,0?8,698 (Anderson et al.)), sometimes called heterogeneous
polymers. The term "linear" does not refer to bulk high pressure branched
polyethylene, ethylene/vinyl acetate copalymers, or ethylene/vinyl alcohol
o~jpolymers uvhich are known to those skilled in the art to have numerous long
chain branches. The term "linear'° also refers to polymers made using
uniform
branching distribution polymerization processes., sometimes called
homogeneous polymers, including narrow IiIIVV~ (e.g. about 2) made using
single site catalysts. Such uniformly branched or homogeneous polymers
include those made as described in IJSP 3,845,992 (Elston) and those made
using so-called single site catalysts in a batch reactor having relatively
high
ethylene concentrations (as described in IJ.S. Patent 5,026,798 (Canich) or in
l~.S. Patent 5,055,438 (Canich)) or those made using constrained geometry
cG~talysts in a batch reactor also having relatively high olefin
concentrations (as
described in ~J.S. Patent 5,064,802 (Stevens et al.) or in EP 0 416 815 A2
(Stevens et al.)). The uniformly branched/homogeneous polymers are those
polymers in which the comonomer is randomly distributed within a given
interpolymer molecule or chain, and wherein suk~stantially al! of the
interpolymer molecules have the same ethylene/'comonomer ratio within that
ini:erpolymer, but these polymers, too, have an absence of long chain
_g_
W~ 95107~d~ 3~~(C'~'l~J~~~/~~fa2;f
r.: ~
,! a. ~ t.a
branching, es, for example, Exxon Chemical has taught in their February 9992
~appi J~~rnel paper (pp 99°903).
properties).
Long chain branching {LCS) is defined herein as a chain length of at
least one {9) carbon less than the number of carbons in the comonomer,
whereas short chain branching {SCS) is defined herein as a chain length of the
same number of carbons in the residue of the comonomer after it is
incorporated into the polymer molecule backbone. for example, en
ethylene/9 moctene substantially linear polymer has backbones with long chain
CA 02171103 2004-11-04
74296-4
branches of at least seven (7) carbons in length, but it also has short chain
branches of only six (6) carbons in length.
Long chain branching can be distinguished from short chain branching
by using 13C nuclear magnetic resonance (NMR) spectroscopy and to a
limited extent, e.g. for ethylene homopolymers, it can be quantified using the
method of Randall (Rev. MacromoLChem. Phys., C29 (2&3), p. 285-297),
However as a
practical matter, current 13C nuclear magnetic resonance spectroscopy cannot
determine the length of a long chain branch in excess of six (6) carbon atoms
and as such, this analytical technique cannot distinguish between a seven (7)
carbon branch and a seventy (70) carbon branch. The long chain branch can
be as long as about the same length as the length of the polymer backbone.
U.S. Patent 4,500,648, teaches that
long chain branching frequency (LCB) can be represented by the equation
LCB=b/Mw wherein b is the weight average number of long chain branches per
molecule and Mw is the weight average molecular weight. The molecular
weight averages and the long chain branching characteristics are determined
by gel permeation chromatography and intrinsic viscosity methods.
The SCBDI (Short Chain Branch Distribution Index) or CDBI
(Composition Distribution Branch Index) is defined as the weight percent of
the
polymer molecules having a comonomer content within 50 percent of the
median total molar comonomer content. The CDBI of a polymer is readily
calculated from data obtained from techniques known in the art, such as, for
example, temperature rising elution fractionation (abbreviated herein as
"TREF") as described, for example, in Wild et al, Journal of Polymer Science,
Poly. Phys. Ed., Vol. 20, p. 441 (1982), or as described in U.S. Patent
4,798;081. The SCBDI or CDBI for the substantially linear ethylene polymers
of the present invention is typically greater than about 30 percent,
preferably
greater than about 50 percent, more preferably greater than about 80 percent,
and most preferably greater than about 90 percent.
"Melt tension" is measured by a specially designed pulley transducer in
:,cnjunctic~~ With the melt indexes. Melt tensie~ is the load that the
extrudate or
-11-
74296-4
CA 02171103 2004-11-04
filament exerts while passing over the pulley onto a two inch drum that is
rotating at the standard speed of 30 rpm. The melt tension measurement is
similar to the "Melt Tension Tester° made by Toyoseiki and is described
by
John Deaiy in 'Rheometers for Molten Plastics", published by Van Nostrand
Reinhold Co. (1982) on page 250-251. The melt tension of the substantially
linear polymers of this invention is also surprisingly good, e.g., as high as
about 2 grams or more. For the substantially linear ethylene interpolymers of
this invention, especially those having a very narrow molecular weight
distribution (i.e., M~Mn from 1.5 to 2.5), the melt tension is typically at
least
about 5 percent; and can be as much as about 60 percent, greater than the
melt tension of a conventional linear ethylene interpolymer having a melt
index, polydispersity and density each within ten percent of the substantially
linear ethylene polymer.
A unique characteristic of the substantially linear polymer is a highly
unexpected flow property where the 110/12 value is essentially independent of
polydispersity index (i.e., M~Mn). This is contrasted with conventional
Ziegler
polymerized heterogeneous polyethylene resins and with conventional single
site catalyst polymerized homogeneous polyethylene resins having rheological
properties such that as the polydispersity index increases; the 110/12 value
also
increases.
Processing Index Determination
The 'rheological processing index" (PI) is the apparent viscosity (in
kpoise) of a polymer and is measured by a gas extrusion rheometer (GER).
The GER is described by M. Shida, R.N. Shroff and t_.V. Cancio in Polym. Eng.
Sci., Vol. 17, no. 11, p. 770 (1977), and in 'Rheometers for Molten Plastics'
by
John Dealy, published by Van Nostrand Reinhold Co. (1982) on page 97-9~.
The processing index is measured at a temperature of 190C, at
nitrogen pressure of 2500 psig using a 0.0296 inch (752 micrometers)
diameter (preferably 0.0143 inch diameter die for high flow polymers, e.g. 50 -
100 melt index or greater), 20:1 UD die having an entrance angle of 180
degrees. The GER processing index is calculated in millipoise units from the
following equation:
-12-
~ 95/07942 P~T'IUS94/1062~
PI = 2.15 % 106 dyne/cm2J(1000 shear rate),
An apparent shear stress vs. apparent shear rate plot is used to identify
the melt fracture phenomena over a range of nitrogen pressures from 5250 to
500 prig using the die or GER test apparatus pr~eviousfy described. According
to amamurthy in Journal of Rheotogy, 30(2), 33'7-357, 10869 above a certain
critical flow rate, the observed extrudate irregularities may be broadly
classified into two main types: surface melt fracture and gross melt fracture.
surface melt fracture occurs under apparently steady flow conditions
arid ranges in detail from loss of specular gloss to the more severe form of
~sl~arkskin". In this disclosure, the onset of surface melt fracture is
characterized at the beginning of losing extrudate gloss at which the surface
roughness of extrudate can only be detected by 40X magnification. The
critical shear rate at onset of surface melt fracture for the substantially
linear
ethylene polymers is at least 50 percent greater than the critical shear rate
at
th~~ onset of surface melt fracture of a linear ethylene polymer having about
the
same 12 and t~~,JMn. Preferably, the critical shear stress at onset of surface
-13-
CA 02171103 2004-11-04
74296-4
melt fracture for the substantially linear ethylene polymers of the invention
is
greater than about 2.8 x 106 dyne/cm2.
Gross melt fracture occurs at unsteady flow conditions and ranges in
detail from regular (alternating rough and smooth, helical, etc.) to random
distortions. For commercial acceptability, (e.g., in blown film products),
surface defects: should be minimal, if not absent. The critical shear rate at
onset of surface melt fracture (OSMF) and critical shear stress at onset of
gross melt fracture (OGMF) are based on the changes of surface roughness
and configurations of the extrudates extruded by a GER. For the substantially
linear ethylene polymers of the invention, the critical shear stress at onset
of
gross melt fracture is preferably greater than about 4 x 106 dyne/cm2.
For the processing index and melt fracture tests, the ethylene polymers
and substantially linear ethylene copolymers contain antioxidants such as
phenols, hindered phenols, phosphates or phosphonites, preferably a
combination of a phenol or hindered phenol and a phosphate or a phosphonite.
Suitable catalysts for use herein comprise constrained geometry
complexes in combination with an activating cocatalyst or activating
technique.
Examples of such constrained geometry complexes, methods for their
preparation and for their activation are disclosed
in EP-A-416,815; EP-A-468,651; EP-A-514,828;
EP-A-520,732; and U.S. Patent 5,374,696; as well as
U.S. Patents: 5,055,438, 5,057,475, 5,096,867, 5,064,802
and 5,132,380.
-14-
~ 95107942 P°C'TIiJS94/10621
Suitable provided metal complexes far use herein correspond to the
form ula:
~Z ~
L Y
cx,)~ c~~,
or dimers thereof,
wherein:
is a Group 4 metal in the +3 or -+-4 formal oxidation state, preferably
is titanium or zirconium, most preferably titaniurr~;
L is a group containing a cyclic, delocalized, aromatic, anionic, II
n is 1 or 2 depending on the formal oxidai:ion state of M.
In one embodiment of this invention, the complexes can be prepared by
contacting a precursor Group 4 metal compound containing 2 displaceable
lic~and groups with a source of a dianionic iigancl, (L-Z-Yj~°, and
optionally, if
-15-
~'~ 951~794, I~~i ~/gJ~9~J~~6~1
', ' ;'
A) ~ ) one or morn of the above metal complexes or the reaction product of
the above described process, and
2) one or more activating cocatalysts;
or
~) the reaction product formed by converting one or more of the above
metal complexes or the reaction product of the above described process to an
active catalyst by use of an activating technique.
Preferred examples of X groups include: hydrocarbyl, carboxylate,
sulfonate, hydrocarbyloxy, siloxy, arnido, phosphido, sulfido, and silyl
groups9
as well as halo-, amino-, hydrocarbyloxy-, siloxy-, silyl-, and phosphino-
substituted derivatives of such hydrocarbyl, carboxylate, sulfonate,
hydrocarbyloxy, siloxy, amido, phosphido, sulfido, or silyl groups; hydride,
halide and cyanide, said group having up to 20 nonhydrogen atoms; or
alternatively, two ?C groups together are a hydrocarbadiyi, or a substituted
hydrocarbadiyl group wherein the substituent is independently each
W~ 95/07942 PC'T/t(1S9~BI10621
occurrence a hydrocarbyl or silyl group of up to 20 nonhydrogen atoms, said
group forming a metallacycle, preferably a metallacyclopentene, with .
tore preferred X groups are hydride, hydrocarbyl (including
cyclohydrocarbyl), hydrocarbyloxy, amido, silyl, silyihydrocarbyl, siloxy,
halide
and aminobenzyl. Especially suited are hydride, chloride, methyl, neopentyl,
b~'nzyl, phenyl, dimethylamido, 2-(PV,fV-dimethylamino)benzyl, allyl, methyl-
substituted allyl (all isomers), pentadienyl, ~-me~thylpentadienyl, 3-
methylpentadienyl, 2,4-dimethylpentadienyl, ~,6-dimethylcyclohexadienyl, and
trimethylsilylmethyi. l~lore preferred of two X groups together are ~-butene-
1,4-diyl, 2,3-dimethyl-1,4-diyl, 2-methyl-~-butene-1,4-diyl, butane-1,4-diyl,
propane-1,3-diyl, pentane-1,5-diyl, and 2-penter~e-~,5-diyl.
Preferred ' groups include phosphines, phosphates, ethers, amines,
carbon monoxide, salts of Group 1 or 2 metals, and mixtures of the foregoing
X' groups. Examples of the foregoing especially include trimethylphosphine,
triethylphosphine, trifluoraphosphine, triphenylphosphine, bas-1,2-
(dimethylphosphino)ethane, trimethytphosphite, ~triethylphosphite,
dirnethylphenylphosphite, tetrahydrofuran, diethyl ether, carbon monoxide,
pyridine, bipyridine, tetramethylethylenediamine (TE~A), dimethoxyethane
(~tree), dioxane, triethylamine, lithium chloride, and magnesium chloride.
Further preferred metal coordination complexes used according to the
present invention correspond to the formula:
Z Y
C IVI ~ CX~
wherein Z, M, Y, X and n are previously defined; and
Cp is a C5H4 group bound to Z and bound in an rt5 bonding mode to
or is such an ~5 bound group substituted with from one to four substituents
independently selected from hydrocarbyl, silyl, germyl, halo, cyano, and
combinations thereof, said substituent having up to ~0 nonhydrogen atoms,
and optionally, two such substituents (except cyano or halo) together cause Cp
to E~ave a fused ring structure.
~'~ 95/0792 ~~"I("I~1~9~1~~6~~
v~ .~
__, . :. C ~: _
I~oro preferred metal coordination complexes used according to the
present invention correspond to the formula:
wherein:
R' each occurrence is independently selected from hydrogen,
hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said ~'
having up to 20 nonhydrogen atoms, and optionally, two ~' groups (where ~' is
not hydrogen, halo or cyano~ together form a divalent derivative thereof
connected to adjacent positions of the cyclopentadienyl ring to form a fused
ring structure;
group from Y form a ring system.
I~I is titanium or zirconium in the +3 or a-4 formal oxidation state; and
3~ is chloro, hydrocarbyl, hydrocarbyloxy, silyl or
N, I~-dialkylamino substituted hydrocarbyl group;
n is ~ or 20
Preferably, ~3' independently each occurrence is hydrogen, hydrocarbyl,
silyl, halo and combinations thereof said R' having up to ~ 0 nonhydrogen
atoms, or two ~t° groups (when R' is not hydrogen or halo) together
form a
divalent derivative thereof; rr~ost preferably, R' is hydrogen, methyl, ethyl,
propyl, butyl, pentyl, hexyl, (including where appropriate all isorners~,
cyclopentyl, cyclohexyl, norbornyl, benzyl, or phenyl or two ~' groups (except
WO 95I~7942 g'C~'II1S94/10621
hydrogen or halo) are linked together, the entire CSR°4 group thereby
being,
for examply, an indenyl, tetrahydroindenyl, fluorenyl, tetrahydrofluorenyl, or
octahydrofluorenyl group.
wherein:
° is independently each occurence selected from hydrogen, silyl,
E is independently each occurrence silic~~n or carbon.
°" is independently each occurrence hydrogen or C~_1p hydrocarbyl;
" is hydrocarbyl or silyl, especially an aryl, benzyl, hydrocarbyl
substituted aryl, hydrocarbyl substituted benzyl, secondary or tertiary alkyl
or
tertiary silyl group of up to 12 nonhydrogen atorr~s;
~1 is titanium in the +3 or +4 formal oxidation state;
mislto2;
n is 1 or 2;
X is methyl, allyl, phenyl, benzyl, chloro, c'.-(N,N-dimethyiamino)benzyl
or trimethylsilylmethyl.
Examples of the metal complexes used according to the present
in~~ention include compounds wherein R" is methyl, ethyl, propyl, butyl,
panty!,
_
Image
t xc: v. vcrv : ~rA- ~~it,EVCHEV 0~ " ._ . _2~'-1 I -95 : ~~_> ; 3q, ; 414
2'?3 5055-~ +q.g gg ~g9gq~465 : # 8
___.. .,.." _____..__..__...
40,121 Q-F ~ . '~ . -_
1-(t-butyiami do )-2-(tetramethyi-~ ~-
cyclopentadienyl)ethanediyititanium {Ifi) 2-(N,PI-dimethylaminolbanzyi
1-it-b~Ylamido)-2-~rl~-indenyl)ethanediyltitanium dimethyi,
'1-(t-butylamido)-2-(rt5 indenyl)ethanediyltitanium dibenzyl,
(t-butyiamido)(~b~e;rahydroindenyl)dimethylsilanetitanium dimethyi,
(t-bu~tylamid~)(~$-tetr,attydroindenyt)dimethylsiianetitanium Biphenyl,
1-(t-butylamido)-2-(rts.tetcahydroindenyl)ethanediyititanium dimethyi,
'1-(t-butylamido)-2-(rl~-tetrahydroindenyl)ethanediyhtitaniurn dibenzyl,
(t-butylamido)(~~-fluorenyl)dimethylsilanetitanium dimethyf,
(t-butyiamido){rl~ ~tuorenyl)dimethylsilanetftanium dibertzyl,
1-(t-butylamido)-2-(~~-tluorenyi)ethanediyititartium dimethyl,
't-(t-butyiamido)-2-~~~-ftuorenyl)ethanediyltitanium dibenzyl,.
{t-butylamidol(~$ tetrahydroftuorenyl)dimethylsilane#itanium dimethyl,
(t-butylamido)(rye-tetrahydroiluorenyi)dimethylsiianetitanium dibenzyl,
1-~t-butylamido)-2-(,~~-tetrahydrofluorenyt)ethanediyltitanium dimethyl,
1-(t-butylamido)-2-(rl~-tetrahydro~luorenyi)ethanediyftitanium dibenzyl
(t-butyiamido)(~b-ottahydrofluoreny!)dimethylsitanetitanium dimethyl
(t-butyiamido){rl5~ctahydrofluorenyi)dimethyisilanetitanium dibenzyl,
1-(t-butylarnido)-2-(~~-octahydrofluorenyl)ethanediyttitanium dirnethyl,
'1-{t-butylamido)-2-(rte-o~hydrofluorenyi)ethanediyititanium dibenzyi,
and the corresponding airconium or hafnium coordination complexes.
The skilled arti$an will recognize that additional members of the
foregoing fist will include the corresponding zirconium or hafnium containing
derivatives, as welt as complexes that are variously substituted as horein
defined.
Most highly preferred met~i complexes used according to the pfesent
inven~on are {9-tent-burfiamido}-2-(tetrsmethyi-~5-
cycfopentadienyl)ethanediyftitanium dfmethyl, 1-(tart-butylamidol-2-~tetra-
methyt-rt5- cyclopentadionyl)ethanediyititanium dibenayi, 1-(tart- butylamido)-
2-,;tetramethyi-,t5- cyciopentadienyl)dimethylsilanetitanium dimethyl, 1-itert-
butylamido)-2-{tetrameti,yt-rid- cyciopentadienyi)dimethyisiiane:~~,ani~;m
dibenzyi,
(t-butylamidfl)(tetramethyf-~rt~-cycivpentadieny!)dimeihyisil2r~titani~:n,
-21-
ANtEfVDED SHEF'i"
CA 02171103 2004-11-04
74296-4
1-(t-butylamido)-2-(tetramethyl-~5-cyclopentad ienyl)ethanediyltitanium,
(t-butylamido)(rt5-tetrahydroindenyl)dimethylsilanetitanium dimethyl,
(t-butylamido)(~5-tetrahydroindenyl)dimethylsilanetitanium Biphenyl,
1-(t-butylamido)-2-(~b-tetrahydroindenyl)ethanediyltitanium dimethyl,
(t-butylamido)(~5-tetrahydrofluorenyl)dimethylsilanetitanium dimethyl,
(t-butylamido)(rt5-tetrahydrofluorenyl)dimethylsilanet'rtanium dibenzyl,
1-(t-butylamido)-2-(~b-tetrahydrofluorenyl)ethan.ediyltitanium dimethyl,
1-(t-butylamido)-2-(~b-tetrahydrofluorenyl)ethanediyltitanium benzyl
(t-butylamido)(rl5-octahydrofluorenyl)dimethylsilanetitanium dimethyl
(t-butylamido)(rl5-octahydrofluorenyl)dimethylsilanetitanium dibenzyl,
1-(t-butylamido)-2-(~5-octahydrofluorenyl)ethanediylt'rtanium dimethyl,
1-(t-butylamido)-2-(~5-octahydrofluorenyl)ethanediyltitanium dibenzyl,
The metal complexes used in this invention are rendered catalytically
active by combination with an activating cocatalyst or by use of an activating
technique. Suitable activating cocatalysts for use herein include neutral
Lewis
acids other than an alumoxane, such as C1-30 hydrocarbyl substituted Group
13 compounds, especially tri(hydrocarbyl)aluminum- or tri(hydrocarbyl)boron
compounds and halogenated (including perhalogenated) derivatives thereof,
having from 1 to 10 carbons in each hydrocarbyl or halogenated hydrocarbyl
group, more especially perfluorinated tri(aryl)boron compounds, and most
especially tris(pentafluorophenyl)borarie; nonpolymeric, compatible,
noncoordinating, ion forming compounds (including the use of such
compounds under oxidizing conditions), especially the use of ammonium-,
phosphonium-, oxonium-, carbonium-, silylium- or sulfonium- salts of
compatible, noncoordinating anions, or ferrocenium salts of compatible,
noncoordinating anions; bulk electrolysis (explained in more detail
hereinafter);
and combinations of the foregoing activating cocatalysts and techniques. The
foregoing activating cocatalysts and activating techniques have been
previously taught with respect to different metal complexes in the following
references: EP-A-277,003, US-5,153,157, US-5,064,802, EP-A-
468,651 and EP-A-520,732.
-22-
W~ 95107942 PC'~'/uJ~94/10621
Preferred anions are those containing a single coordination complex
comprising a charge-bearing metal or metalloid core which anion is capable of
balancing the charge of the active catalyst species (the metal canon) which
may be formed when the two components are combined. Also, said anion
stoould be sufficiently labile to be displaced by olefinic, diolefinic and
ac;etylenically unsaturated compounds or other r~eutra! Lewis bases such as
ethers or nitrites. Suitable metals include, but are not limited to, aluminum,
gold and platinum. Suitable metalloids include, but are not limited to, boron,
phosphorus, and silicon. Compounds containing anions which comprise
coordination complexes containing a single metal or metalloid atom are, of
course, well known and many, particularly such compounds containing a single
boron atom in the anion portion, are available commercially.
_2g_
CA 02171103 2004-11-04
74296-4
Preferably such cocatalysts may be represented by the following
general formula:
[~t-H]+d(Ad-1
wherein:
L' is a neutral Lewis base;
[L*-H]+ is a Bronsted acid;
Ad- is a noncoordinating, compatible anion having a charge of d-, and
d is an integer from 1 to 3.
More preferably Ad- corresponds to the formula: [M'k+Qn']d' wherein:
k is an integer from 1 to 3;
n' is an integer from 2 to 6;
n'-k = d;
M' is an element selected from Group 13 of the Periodic Table of the
Elements; and
Q independently each occurrence is selected from hydride,
dialkylamido, halide, hydrocarbyl, hydrocarbyloxy, halosubstituted-
hydrocarbyl,
halosubstituted hydrocarbyloxy, and halo substituted silylhydrocarbyl radicals
(including perhalogenated hydrocarbyl- pefialogenated hydrocarbyloxy- and
perhalogenated silylhydrocarbyl radicals), said Q having up to 20 carbons with
the proviso that in not more than one occurrence is Q halide. Examples of
suitable hydrocarbyloxide Q groups are disclosed in U. S. Patent 5,296,433.
In a more preferred embodiment, d is one, i. e., the counter ion has a
single negative charge and is A-. Activating cocatalysts comprising boron
which are particularly useful in the preparation of catalysts of this
invention
may be represented by the following general formula: (L'-H]+ [BQ41-
wherein:
[L'-H]+ is as previously defined;
B is boron in a valence state of 3; and
Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-,
fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl- group of up to
20
nonhydrogen atoms, with the proviso that in not more than one occasion is Q
-24-
W~ 9510?942 PC~'IIJS94I1~621
hydrocarbyl. Most preferably, Q is each occurrence a fluorinated aryl group,
especially, a pentafluorophenyl group.
Illustrative, but nat limiting, examples of boron compounds which may
be used as an activating cocatalyst in the preparation of the improved
catalysts
of this invention are tri-substituted ammonium salts such as:
trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate,
tripropylammonium tetraphenylborate,
tri(n-butyl)ammonium tetraphenylborate,
tri(t-butyl)ammonium tetraphenyiborate,
N,N-dimethylanilinium tetraphenylborate,
N,N-diethylanilinium tetraphenylborate,
N,N°dimethyl-2,4,6-trimethylanilinium tetraphenylborate,
trimethylammonium
tetrakis(pentafiuorophenyl) borate,
triethylammonium tetrakis{pentafluorophenyl) borate,
tripropylammonium tetrakis(pentafluorophenyl) borate,
tri{n-butyl)ammonium tetrakis(pentafluorophenyl) borate, tri(sec-
butyl)ammonium tetrakis(pentafluorophenyl) borate,
N,N°dimethylanilinium tetrakis(pentafiuorophen'/I) borate,
N,N-dimethylanilinium n-butyltris(pentafluorophenyl) borate,
N,N-dimethyianilinium benzyltris(pentafluorophenyl) borate,
N,N-dimethylanilinium tetrakis(4-(trimethylsilyl)-?, 3, 5, 6-
tetrafluorophenyl)
borate, N,N-dimethylanilinium tetrakis(4-(triisopropylsilyl)-2, 3, 5, 6-
te~trafluorophenyl) borate, N,N-dimethyianilinium
pentafluorophenoxytris(pentafluorophenyl) borate,
N,N-diethylanilinium tetrakis(pentafluorophenyl) borate, N,N-dimethyl-2,4,6-
trimethyianilinium tetrakis(pentafluorophenyl) borate,
trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate,
triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate,
tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate,
tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate,
dimethyl(t-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate,
N,N-dimethyianilinium tetrakis(2,3,4,6-tetrafluorophenyl) borate,
N,N-diethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl) borate, and
N,N-dimethyl-2,4,6-trimethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl)
borate;
dialkyl ammonium salts such as:
-25-
~'~ 95/07942 I~CC1C/E~J~9~I~0~~~
.. > .. -~, . ~~ ~_
Preferred [L''-H]~ cations are ~I,N-dirr~ethylar~ilinium and
tributylamm~niur~.
~rtother suitable iota forming, activating cocatalyst comprises a salt of a
cationic oxidizing agent and a noncoordinating, compatible anion represented
by the formulae
(~~e~)d(~d-)e
wherein:
~xe~' is a cationic oxidizing agent having a charge of e°~9
a is an integer from ~ to 3; and
Ad- and d are as previously defined.
~xar~ples of cationic oxidizing agents include: ferrocenium, hydrocarbyl-
substituted ferroceniurn, Age, or Pb'~~. Preferred ernbodirnents of Ad- are
those anions previously defined with respect to the ~ronsted acid containing
activating cocatalysts, especially tetrakis(pentafluorophenyl)borate.
-2~-
CA 02171103 2004-11-04
74296-4
Another suitable ion forming, activating cocatalyst comprises a
compound which is a salt of a carbeniurri ion and a noncoordinating,
compatible anion represented by the formula:
Oi-A'
wherein:
C~ is a C1_20 carbenium ion; and
A- is as previously defined. A preferred carbenium ion is the trityl
ration, i.e., triphenylmethylium.
A further suitable ion forming, activating cocatalyst comprises a
compound which is a salt of a silylium ion and a noncoordinating, compatible
anion represented by the formula:
R3Si(X')q+A-
wherein:
R is C1_10 hydrocarbyl, and X', q and A- are as previously defined.
Preferred silylium salt activating cocatalysts are trimethylsilylium
tetrakis(pentafluorophenyl)borate,
triethylsilylium(tetrakispentafluoro)phenylborate and ether subst'ttuted
adducts
thereof. Silylium salts have been previously generically disclosed in J. Ghem
Soc. Chem.Comm., 1993, 383-384, as well as Lambert, J. B., et al.,
Organometallics, 1994, 13, 2430-2443. The use of the above silylium salts as
activating cocatalysts for addition polymerization catalysts
is known.
Certain complexes of alcohols, mercaptans, silanols, and oximes with
tris(pentafluorophenyl)borane are also effective catalyst activators and may
be
used according to the present invention. Such cocatalysts are disclosed in
USP 5,296,433. Preferred complexes include phenol,
especially fluorinated phenol adducts of
tris(pentafluorophenyl)borane. The latter cocatalysts are
disclosed and
-27-
CA 02171103 2004-11-04
74296-4
claimed in United States Patent 5,296,433.
The technique of bulk electrolysis involves the electrochemical oxidation
of the metal complex under electrolysis conditions in the presence of a
supporting electrolyte comprising a noncoordinating, inert anion. In the
technique, solvents, supporting electrolytes and electrolytic potentials for
the
electrolysis are used such that electrolysis byproducts that would render the
metal complex catalytically inactive are not substantially formed during the
reaction. More particularly, suitable solvents are materials that are: liquids
under the conditions of the electrolysis (generally temperatures from 0 to
100C), capable of dissolving the supporting electrolyte, and inert. "Inert
solvents" are those that are not reduced or oxidized under the reaction
conditions employed for the electrolysis. It is generally possible in view of
the
desired electrolysis reaction to choose a solvent and a supporting electrolyte
that are unaffected by the electrical potential used for the desired
electrolysis.
Preferred solvents include difluorobenzene (all isomers), dimethoxyethane
(DME), and mixtures thereof.
The electrolysis may be conducted in a standard electrolytic cell
containing an anode and cathode (also referred to as the working electrode
and counter electrode respectively). Suitable materials of construction for
the
cell are glass, plastic, ceramic and glass coated metal. The electrodes are
prepared from inert conductive materials, by which are meant conductive
materials that are unaffected by the reaction mixture or reaction conditions.
Platinum or palladium are preferred inert conductive materials. Normally an
ion permeable membrane such as a fine glass frit separates the cell into
separate compartments, the working electrode compartment and counter
electrode compartment. The working electrode is immersed in a reaction
medium comprising the metal complex to be activated, solvent, supporting
electrolyte, and any other materials desired for moderating the electrolysis
or
stabilizing the resulting complex. The counter electrode is immersed in a
mixture of the solvent and supporting electrolyte. The desired voltage may be
determined by theoretical calculations or experimentally by sweeping the cell
using a reference electrode such as a silver electrode immersed in the cell
-28-
CA 02171103 2004-11-04
74296-4
electrolyte. The background cell current, the current draw in the absence of
the desired electrolysis, is also determined. The electrolysis is completed
when the current drops from the desired level to the background level. In this
manner, complete conversion of the initial metal complex can be easily
detected.
Suitable supporting electrolytes are salts comprising a ration and a
compatible, noncoordinating anion, A-. Preferred supporting electrolytes are
salts corresponding to the formula G+A-; wherein:
G+ is a ration which is nonreactive towards the starting and resulting
complex, and
A- is as previously defined.
Examples of rations, G+, include tetrahydrocarbyl substituted
ammonium or phosphonium rations having up to 40 nonhydrogen atoms.
Preferred rations are the tetra-n-butylammonium- and tetraethylammonium-
rations.
During activation of the complexes of the present invention by bulk
electrolysis the ration of the supporting electrolyte passes to the counter
electrode and A- migrates to the working electrode to become the anion of the
resulting oxidized product. Either the solvent or the ration of the supporting
electrolyte is reduced at the counter electrode in equal molar quantity with
the
amount of oxidized metal complex formed at the working electrode. Preferred
supporting electrolytes are tetra.hydrocarbylammonium salts of
tetrakis(perfluoroaryl) borates having from 1 to 10 carbons in each
hydrocarbyl
or perfluoroaryl group, especially tetra-n-butylammonium
tetrakis(pentafluorophenyl) borate.
A further recently discovered electrochemical technique for generation
of activating cocatalysts is the electrolysis of a disilane compound in the
presence of a source of a noncoordinating compatible anion. This technique is
more fully disclosed and claimed in United States
Patent 5,625,087.
~V~ 951079~~ I~~'~'IgT~~~lb~6~.ll
- ',,
the foregoing activating techniques and ion forming cocatalysts are
also preferably used in cor~binatior~ ~itc~ a tri(hydrocarbyl)al~rnin~r~ or
tri(hydrocarbyl)borane compound having from ~ to ~ carbons in each
hydrocarbyl groups
acid, especially tris(pentafluorophenyl)borane.
Upon activation of the metal complexes containing taro distinct ~C
groups, utilizing one of the preceding cation forming activating cocatalysts
or
activating techniques, there is believed to be formed, ~titho~t wishing to be
bound by such belief, a cationic metal complex corresponding to the formula:
Z Y
L
t~~-1
whereine
I~i9 ~9 Z, ~, X', , n, and q are as previously defined, and
~° is as previously defined and is the noncoordinating anion from the
activating cocatalyst or is formed concurrently by the activating technique.
-30-
~ 95/07942 ~~'T'Ii159411062~
lJtilizing the preferred neutral Lewis acid activating cocatalyst,
~(C~~~)3 , A° of the foregoing cationic metal complexes is believed to
correspond to the formula: ~(C6F~)~°,wherein X is as previously
defined.
The preceding formula can be considered as a limiting, charge
separated structure. However, it is to be understood that, particularly in
solid
form, the catalyst may not be fully charge separated. That is, the group may
retain a partial covalent bond to the metal atorr~, t~.
Z Y
tVf ~ X
Z
L ~. Ci?3 Cf~R6
CRt R2
~~ 9~l~7~4~ I~e~'~'/~J~~~l~~~~~
~,
'e
whereine
~ as t~t~r9i~r~ or arc~ni~r~p
~y ~y and ~ are as proveousiy def'ned,
i:3~ y ~~y ~~, ~~., R~, and ~6 are independently each occurrence
hydrogen or a hydrocarbyl or silyl group having from ~ to 2~ r~onhydroger~
atoms;
~ is boron ire a valence state of 3, and
~ is as previously defined.
~ther catalysts which are useful as the catalyst compositions of this
inve~tior~y especially compounds containing other Croup ~ metals9 wills of
courser be apparent to those skilled in the art.
~escriotion of a Continuous Polymerization
'fhe ~oiymerization reaction
to initiate the polymerization reaction.
CA 02171103 2004-11-04
74296-4
Typically the various comonomers that are copolymerized with ethylene
in order to provide polymers having the desired density range at any given
melt index range from 0 to 20 mol percent in the copolymer. The relative molar
concentration of such comonomers to ethylene (CX/C2), which are present
under reaction equilibrium conditions in the reactor will vary depending on
the
choice of comonomer and the desired copolymer density.
A fluidized bed reaction system which can be used in the practice of the
process of the present invention is taught in
U.S. Patent 4,543,399. A typical fluidized bed
reactor can be described as follows:
The bed is usually made up of the same granular resin that is to be
produced in the reactor. Thus, during the course of the polymerization, the
bed comprises formed polymer particles, growing polymer particles, and
catalyst particles fluidized by polymerization and modifying gaseous
components pass upward through the bed at a flow rate or velocity sufficient
to
cause the particles to remain separated with the bed exhi5iting fluid-like
behavior. The fluidizing gas comprises the initial gaseous feed of monomers,
make-up feed, and cycle (recycle) gas, i.e., comonomers, hydrogen and, if
desired, an inert carrier gas. Examples of such inert carrier gases include
nitrogen, methane, ethane or propane, which are inert with respect to the
polymerization reaction.
The essential parts of the reaction system are the polymerization
reaction vessel, catalyst injection system, the fluidized bed, the gas
distribution
plate, inlet and outlet piping, a compressor, cycle gas cooler, and a product
discharge system. In the vessel, there is a reaction zone which contains the
bed and a velocity reduction zone which is above the reaction zone. Both are
above the gas distribution plate. Advantages of the product of subject process
are the homogeneity and uniformity of the physical properties throughout the
resulting polymer and the high strength and toughness obtained without
processing difficulty.
-33-
CA 02171103 2004-11-04
74296-4
It will be apparent to the skilled artisan that use of a supported
constrained geometry catalyst increases the range of reactor conditions.that
may be used before condensing components in the recycle stream. But if one
chooses to condense components in the recycle stream, then it may be
desirable in some instances to raise the dew point temperature of the recycle
stream to further increase heat removal as taught in U.S. Patents 4,543,339
and 4,588,790 . The recycle stream dew
point temperature can be increased by: (1 ) raising the operating pressure of
the reaction system; (2) increasing the concentrations of inert condensable
compounds in the reaction system; and/or (3) reducing the concentration of
inert non-condensable compounds in the reaction system. In one embodiment
of this invention, the dew point temperature of the recycle stream may be
increased by the addition of a condensable fluid to the recycle stream which
is
inert to the catalyst, reactants, and the products of the polymerization
reaction.
me fluid can be introduced into the recycle stream with the make-up fluid or
by
any other means or at any other point in the system. Examples of such fluids
are saturated hydrocarbons, such as butanes, pentanes or hexanes.
A primary limitation on the extent to which the recycle gas stream can
be cooled below the dew point is in the requirement the gas to-liquid ratio be
maintained at a level sufficient to keep the liquid phase of the two-phase
recycle mixture in an entrained or suspended condition until the liquid is
vaporized. It is also necessary for sufficient velocity of the upwardly
flowing
fluid stream in the reaction zone to maintain fluidization of the bed. This
limitation can be overcome by collecting the condensed phase and introducing
it to the fluidized bed separately from the recycled gaseous stream.
Multiple reactor polymerization processes are also useful in the present
invention, such as those disclosed in U.S. Patents 3,914,342, 5,047,468,
5,126,398 and 5,149,738..
The multiple reactors can be operated in series or in parallel, with at least
one
constrained geometry catalyst employed in at least one of the reactors.
In this aspect of this invention resins are manufactured and blended in situ.
Multiple reactor polymerization processes may be used to produce in-situ
blended polymers with enhanced physical properties and/or processability. In-
situ blends of dififierent molecular weights and/or different densities may be
-34-
CA 02171103 2004-11-04
74296-4
produced for specific and desired physical and/or processability requirements.
For example, two reactors can be used in series to produce resins with a
bimodal molecular weight distribution. In another example, two reactors could
produce resins with a bimodality in density or short chain branching. More
than two reactors in series can be used to make more molecular weight or
density components for in-situ blends. Each reactor separately can have a
constrained geometry catalyst or a conventional Ziegler-Natta catalyst as
needed for obtaining the in-situ blended polymer with the desired properties,
as long as there is a constrained geometry catalyst in at least one reactor.
The constrained geometry catalysts may be used singularly, in
combination with other constrained geometry catalysts, or in conjunction with
Zeigler-type catalysts in separate reactors connected in parallel or in
series.
The Zeigler catalyst is generally a titanium based complex suitably prepared
for use as a catalyst for the gas phase polymerization of olefins. This
complex
and methods for its preparation are disclosed in U.S. Patents 4,302,565,
4,302,566, 4,303,771, 4,395,359, 4,405,495, 4,481,301, and 4,562,169.
The polymerization in each reactor is conducted in the gas phase using
a continuous fluidized bed process. A typical fluidized bed reactor is
described in U.S. Pat. No. 4,482,687 issued on Nov. 13, 1984.
As noted, the reactors may be connected in
series as taught in U.S. Patents 5,047,468, 5,126,398, and 5,149,738 .
While two reactors are preferred, three
or more reactors can be used to further vary the molecular weight
distribution.
As more reactors are added producing copolymers with different average
molecular weight distributions, however, the sharp diversity of which two
reactors are capable becomes less and less apparent. It is contemplated that
these additional reactors could be used to produce copolymers with melt
indices or densities, intermediate to the high and low melt indices previously
referred to.
As noted previously, two or more reactors may be run in parallel with the
resulting polymeric product being blended. This permits the reactors to be run
independently, with different catalysts, different amounts of ethylene and
-35-
CA 02171103 2004-11-04
74296-4
alpha-olefins, different recycle rates and at different productivity rates.
The
various melt indices can be prepared in any order, i.e., in any reactor in the
series. For example, the low melt index copolymer can be made in the first or
second reactor in the series and the high melt index copolymer can be made in
the first or second reactor as well. The actual conditions used will depend on
the comonomer used and the desired copolymer properties and are readily
ascertained by the skilled artisan.
The constrained geometry catalyst, the ethylene monomer; any
comonomers and hydrogen, ff any, are continuously fed into each reactor and
ethylene copolymer and active catalyst are continuously removed from one
reactor and introduced into the next reactor. The product is continuously
removed from the last reactor in the series.
The alpha-olefins used in this aspect of the invention are the same as
those that have been previously described in this application. Preferred alpha-
olefins are 1-butane, propylene, 1-hexane, 1-octane, 4-methyl-1-pentane and
styrene.
~ul2~oorted Hom2qeneous Catalyrsts
Supported homogeneous catalyst complexes can be used in
the process taught by applicants.
The Catalyst Support
Typically, the support can be any of the known solid catalyst supports,
particularly porous supports, such as talc, inorganic oxides, and resinous
support materials such as polyolefins. Preferably, the support material is an
inorganic oxide in particulate form.
Suitable inorganic oxide materials which are desirably employed in
accordance with this invention include Group 2, 3, 4, 13, or 14 metal oxides.
The most preferred catalyst support materials include silica, alumina, and
silica-alumina, and mixtures thereof. Other inorganic oxides that may be
-36-
~'~ 95/07942 P~'T/i1~94/~0621
N.
employed either alone or in combination with the silica, alumina, or silica-
alumina are magnesia, titania, zirconia. Other suitable support materials,
however, can be employed, for example, finely divided polyolefins such as
finely divided polyethylene.
Chemical dehydration or chemical treatment to dehydrate the support
may be accomplished by slurrying the inorganic particulate material, such as,
~~or example, silica in an inert low boiling hydrocarbon, such as, for
example,
silica in an inert low boiling hydrocarbon, such as, for example, hexane.
wring the chemical dehydration reaction, the aupport, preferably silica,
should
be maintained in a moisture and oxygen-free atmosphere. To the silica slurry
_3~_
~'~ 95/~79~~ ~f~'~I'ItiJ~9b/~~~~~
..r
.. a .n .. "sJ
Ire ~rder ~h~~ pers~ns skil9~d in the ark rna~r beater underscored the
Ex~~rirnen~ai
_3~_
CA 02171103 2004-11-04
74296-4
gases then pass through a gas booster pump. The polymer is allowed to
accumulate in the reactor over the course of the reaction. The total system
pressure is kept constant during the reaction by regulating the flow of the
ethylene into the reactor. Polymer is removed from the reactor to a recovery
vessel by opening a valve located at the bottom of the fluidization zone. The
polymer recovery vessel is kept at a lower pressure than the reactor. The
pressures of ethylene, comonomer and hydrogen reported refer to partial
pressures. The polyethylene powders used as supports were high density
homopolymers. The titanium complex, (C5Me4SiMe2NCMe3)TiM~2 is
prepared according to U.S. Patent 5,189,192,
and the borane complex, B(C6F5)3 is prepared according to the
procedure taught in Z. Naturforsch. ~Q~, 5-11 (1965).
Prior to being used as supports, the silicas were treated with the
aluminum alkyl, triethylaluminum (TEA). The purpose of this pretreatment was
to remove from the silica any residual water and/or hydroxyl groups. Following
the pretreatment, the silicas were then washed several times with toluene to
remove any residual TEA or alumoxane which may have resulted during the
dehydration process. The supports were then dried under reduced pressure.
In some cases the supports were washed with hexane before drying. Any
amount of alumoxane which may have remained on the silica was present in a
non-activating amount (see Examples 20 and 21 ).
I 1
Catalyst/support preparation
An aliquot (4 mL) of a 0.005 M solution (60 Nmol) of
(C5Me4SiMe2NCMe3)TiMe2 in toluene and 4.8 mL of a 0.005 M solution (60
Nmol) of B(C6F5)3 in toluene were stirred with 0.640 g of high density
polyethylene powder having zero melt index which previously had been sieved
to remove any particles larger than 25 mesh. The solvent was removed to give
a pale yellowish free-flowing powder. The resulting catalyst composition was
divided into two portions, each weighing about 0.32 g.
Polymerization
-39-
1~(~~IYI~1~~4~/~l~~e~~
~~ 95107~4~
w~
__J ~( t. 4
Catalyst/support preparation
~olyrr,eriz~tion
~x~rr»I~ 3
Catalystlsupport preparation
in a ~ar~r~er substantially the same as in Example ~ , except that 2 r~~
(~0 Nrz~ol) of the (C5~e4Si~e2~~~e3)TiMe~ solution and ~.~ m~. (~~ pmol) of
the ~(COE~)~ solution were combined with 0.600 g of t ~ .~ melt index
egp_
WO 95107942 PCT/US94/10621
~17~103
polyethylene powder to prepare the supported catalyst. 0.30 g of the resulting
supported catalyst (5 Nmol titanium complex, 6 Nmol borane complex) was
used in the following polymerization.
Polymerization
The polymerization was carried out in two stages, similar to Example 2,
except that the ethylene pressure was 300 psi. No hydrogen was present
during the polymerization. The initial temperature was 61 °C. The
second
portion of catalyst was added about 1 hour after the first portion of catalyst
had
been added. The yield of granular polymer having a melt index of zero was
25.4 g.
Examl la a 4
Catalyst/support preparation
A polyethylene-supported catalyst was formed analogous to Example 3,
except that 0.59 melt index polyethylene and 12 Nmol of the borane complex
were used.
Polymerization
The polymerization was carried out analogous to Example 3, except that
the ethylene pressure was 290 psi. No hydrogen was present during the
polymerization. The initial temperature was 66°C. An exotherm of
4°C was
observed on addition of the first portion of catalyst. An exotherm of
24°C was
observed on addition of the second portion of catalyst. The yield of granular
polymer having a melt index of zero was 43.9 g. '
Exam,~he 5
Catalyst/support preparation
An aliquiot (4 mL) of a 0.~05 M solution {20 Nmol) of
(C5Me4SiMe2NCMe3)TiMe~°rn'~aJ~~~~ and 4.8 mL of a 0.005 M solution (24
_~.1 _
m.v. r__~o,~~~~.:.vtl.c:y Vb
r ILy
~.. -_ . =='' _ 11 X95 : '?~or ;34
...-. _____ 41~ 223 5055.-~ +49 g9 2:3994
4ss:# s
40,121Q-F . . _~ ~___
2~~7910~
umolj of B(C6F5)3 in toluene were s#irred with O.CGO g of Q.33 melt index high
density polyethylene pQ,,~er which previously had been sieved to remove an
Y
particl$s larger than 25 mesh. The solvent was removed to give a pale
yellowish free-tlnwing Powder.
Polymerization
An amount (0.30 g; 10 Nmol titanium Complex, 12 Nmol borane complex)
of the solid supported catalyst was Introduced into a fluidizsd bed reactor
preSSUrized to 260 psi ethyie,~ ~rytaining 0.25 rnol '~G (based on ethylene
0.6,5 psij hydrogen at a temperature of 53°C. After a run time of 5
hours 81 g
of polyethylene hawing a melt index of 1.30 was removed. The productivity
was 169;000 g polymerlg Ti.
Exam~nle 6_
Catalystfsupport preparation
1n a manner substantially the same as in F~carriple 1, except that 2 mL
(10 ~rmol) of the (C6Me~SilVle2NCMe3)TilIAe2 solution and 2.4 mL (12 Nmot) of
the B(C6F5j3 solution were combined with 0.60Q g of 0.33 melt index
polyothyiene powder to prepare the supported catalyst. 0.30 g of the resulting
$uPPa~ed catalyst (5 Nmol titanium complex, 6 pmol borane complex) ryas
used in the following pvtyrr~eriZ~on.
Polymerlaation
The polymerization yeas carried out as In Example 5, except that the
ethylene and hydrogen pre$sures were 230 psi and O. d6 psi (Q_20 mol %),
respectively, at a temperature of 47~C. The yield of polymer having a melt
index of 0.65 was 27, 0 g.
-~.2-
AMENDED SHEET
~ 95/07942
Exam Bye 7
Polymerization
PCT'/CTS94/10621
The polymerization was carried out as in Example 6, except that the
ethylene and hydrogen pressures were 230 psi and 1.4 psi (0.50 mol
°/~)y
respectively, at a temperature of 55°C. The yield of polymer having a
melt
index of 17.3 was 11.6 g.
Exam Ip a 3
~atalyst/support preparation
Polymerization
lJsing the catalystlsupport prepared above, the polymerization was
carried out in a manner similar to Example 5, excoept that the ethylene and
hydrogen pressures were X70 psi and 0.3 psi (0.30 mol ~/~), respectively, at a
temperature of 60°C. The yield of polymer having a melt index of 3.0
was 30.4
g.
_43_
~'~ ~5l~7~~~ ~'~B'l~1~~9/~t~~2ll
,;
J
~X~r$"i~~~S ~~1 ~
Supp~rt preparation
°~h~ silicas ~er~ pretreated pri~r t~ catalyst ~dditior~ pith
~ac~urra.
Preparati~n ~~ the supported catalyst
General pelyrraeri~ation procedure
~~4_
~R'~ 95107942 PC1'/ITS94I10621
n.
iExam 9~c a 20
~;atalyst/support preparation
~avison 952 silica was pretreated as in Examples 9-19 under '°Support
preparation'° using 0.5 mL of TEA and 2.0 g silica.
The catalyst was prepared as in Examples 9-19 under "Preparation of
the Supported catalyst" using 3 g.mole of (CSA~Je4Sie2NCe3)Ti~e2, 9
.mole of ~(C6F5)3 and 0.10 g of the above treated silica.
Polymerization
The solid supported catalyst was invrodu~ced into the fluidized bed
reactor pressurized with 240 psi ethylene, 9 psi 1-butane, 1.2 psi hydrogen
and
51 psi nitrogen. The initial temperature was 74~ and the run time was 7~
minutes. The yield of granular powder was 5.5 g.
Example 21
Catalyst/support preparation
l9sing the silica of Example 20, the silica-supported catalyst was
prepared analogously to Example 20 except that none of the borane complex
was added to the support.
Polymerization
The solid supported catalyst was introduced into the fluidized bed
reactor pressurized with 240 psi ethylene, 9 psi '1-butane, 1.2 psi hydrogen
and
51 psi nitrogen. The initial temperature was 75C and the run time was 75
minutes. No polymer was recovered from the reactor, indicating that any
aluminum compounds possibly remaining after washing the silica to remove
re:;idual TEA are only present at non-activating levels.
_45_
~~ 95l~7~~~ I1'~'~'/I1i11~~~1g~~~~
-~, ,
fi_~, ~ ~ ~ ~,.
~x~r~ 1
~~t~9yst9support preparation
f~rop~r~tior~ of the supported catalyst was analogous to ~~~rnple 20
except that ~2 ~.rnole of ~~~6F5)3 and 4 ~.rnole of
(C5e4Si~le2l~Ceg)Ti&~e2, were added to 0.20 g of the treated si6ica.
~olyrr~eri~ati~r~
The solid supported catalyst was introduced into the fluidized bed
reactor pressurized with 240 psi ethylene, ~ .5 psi, ~ ,5-hexadsene, ~ .2 psi
hydrogen, and 60 psi nitrogen. The initial temperature was 76 ~ and the run
$irne eras X26 minutes. 21 g of free flowing polymer powder were rerruo~ed.
Examele 23
~atalystdsupport preparation
The supported catalyst was prepared analogously 9~0 ~xarnple 22.
polymerisation
The solid supported catalyst was introduced into the fiuidized bed
reactor pressurized with 240 psi ethylene, 0.75 psi 1,5-hexadiene, ~ .2 psi
hydrogen, and 60 pie nitrogen. The initial temperature was ~0 C and the run
titres was ~ ~7 minutes. 1 ~ .6 g of free flowing polymer powder were removed.
m46-
~ 95/07942 P~TiYYTS94110621
E~~am h 24
Catalystlsupport preparation
Preparation of the supported catalyst vuas analogous to Example 20
except that 9 mole of E(Cgl°5)3p 3 p.mole of (C~P~Ie~ ;ie2NCi~e~)Tie2,
and 0.10 g of the treated silica r~rere used.
Polymerization
Exam ire 25
Catalystlsupport preparation
The supported catalyst vvas prepared an~~logously to Example 24.
Polymerization
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