Note: Descriptions are shown in the official language in which they were submitted.
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HIGHLY CRYSTALLINE EAODM INTERPOLYMERS
FIELD OF THE INVENTION
This invention relates to random
ethylene/alpha (oc)-olefin/polyene (EAODM) interpolymers
containing at least 84 weight percent (wt~) ethylene
and the use of such interpolymers in combination with
other polyolefins, rubbers, and thermoplastic
formulations. This invention also relates to
crosslinked or cured EAODM interpolymers and the use of
such crosslinked interpolymers to produce fabricated
articles including, but not limited to, wire and cable
products, foams, automotive components, tubing, tapes,
laminates, coatings and films. This invention further
relates to blends of the polymers of this invention
with both natural and synthetic polymers, especially to
thermoplastic polyolefins (TPO). This invention
additionally relates to EAODM polymers that are grafted
with other monomers, such as unsaturated carboxylic
acid monomers, and the use of such grafted
interpolymers as, for example, impact modifiers,
compatibilizers and adhesion promoters.
BACKGROUND OF THE INVENTION
Polyolefins are used in numerous applications
including, but not limited to, wire and cable
insulation, automotive interior skins, impact
modification of other polyolefins, foams, and films.
Many of these applications demand ever-increasing
improvements in heat resistance. One method to improve
polyolefin heat resistance involves crosslinking or
curing the polyolefin using either a source of
radiation such as electron beam (EB) radiation, gamma
radiation or ultraviolet (W) radiation, or a heat-
activated chemical crosslinking agent such as a
peroxide. Additionally, when the polyolefin contains
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unsaturation, the heat-activated chemical crosslinking
agent may be sulfur, a phenolate, or a silicon hydride.
Manufacturers of cured elastomeric parts engage in an
ongoing search for polyolefins with improved curing
characteristics that provide one or more additional
benefits such as faster productivity to reduce
manufacturing costs.
For polyethylene (PE), an increase in
crosslink density typically requires using more
peroxide or an increased level of radiation exposure,
both of which increase cost. Those who work with PE
desire an effective, but more economical approach.
The interpolymers of this invention have
unsaturated sites that permit grafting of polar
materials onto the interpolymer backbone. Skilled
artisans recognize that nonpolar polyolefins,
particularly PE, provide poor substrates for
application of polar coating materials such as paint.
In order for paint to effectively adhere to PE, PE
surfaces are usually treated to improve compatibility
using techniques such as flame surface treatment and
corona discharge. An alternate technique changes the
polymer itself and involves grafting polar materials
onto the polymer backbone.
2 5 SUN~lARY OF THE INVENTION
One aspect of the present invention is an
interpolymer composition comprising a random EAODM
interpolymer that comprises (a) ethylene in an amount
of from 84 to 99 weight percent (wt~), (b) an oc-olefin
containing from 3 to 20 carbon atoms (C3_ZO) in an amount
within a range of from greater than (>) 0 to less than
(<) 16 wto, and (c) a polyene in an amount of from > 0
to 15 wt~, all percentages being based upon
interpolymer weight and selected to total 100 weight
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percent, the interpolymer having a crystallinity > 16
percent and a glass transition temperature (Tg) of -45°
centigrade (°C) or greater. By way of example, a Tg of
-40°C is > a Tg of -45°C. For comparison, an EAODM
having 85 wto ethylene, 10 wt% propylene, and 5 wt~
diene has a 91.5 molo ethylene content. The resulting
interpolymers may, if desired, be crosslinked
chemically using agents such as peroxides, sulfur,
phenolates and silicon hydrides or by radiation using
any of EB, gamma and W radiation.
As used herein, "interpolymer" refers to a
polymer having polymerized therein at least three
monomers. It includes, without limitation, terpolymers
and tetrapolymers. A "copolymer" has polymerized
therein two monomers.
When crosslinked, the ethylene interpolymers
of this invention exhibit improved mechanical strength,
heat resistance, and cure properties relative to
crosslinked ethylene interpolymers prepared from the
same monomers but with a lower ethylene content.
DETAILED DESCRIPTION OF THE INVENTION
Skilled artisans recognize that polyolefins with
unsaturation have greater crosslinking efficiency than
those that lack unsaturation. Improved crosslink
efficiency generally translates into faster cure,
increased mechanical strength, and, for an end use
manufacturer, increased productivity. The EAODMs of
the present invention, when blended with polyolefins,
provide a means to increase polyolefin crosslink
density without resorting to conventional techniques
such as using more peroxide or increasing radiation
exposure.
Polymer crystallinity has an impact on
physical properties such as tensile strength, green
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strength, and flex modulus. Reductions in polymer
crystallinity typically lead to a corresponding
reduction in tensile strength, green strength, and flex
modulus. Commercially available polyolefins, such as
high density polyethylene (HDPE), typically have a
crystallinity within a range of 45o to 95~.
Conventional EAODM polymers have a crystallinity within
a range of Oo to 160. When such conventional EAODM
polymers are blended with HDPE or another crystalline
polyolefin, the resulting blend has a reduced
crystallinity relative to the crystalline polyolefin.
By way of contrast, the EAODMs of the present invention
have a crystallinity, measured by Differential Scanning
Calorimetry (DSC), within a range of from > 16 wt% to
<75 wto, preferably from > 19 wt~ to 40 wt~.
Unless otherwise stated herein, a numerical
range includes both endpoints.
EAODM interpolymers suitable for this
invention include polymers having polymerized therein
ethylene, at least one C3_zo, Preferably C3_lo, oc-olefin,
and at least one polyene. Skilled artisans can readily
select appropriate monomer combinations for any desired
interpolymer so long as the interpolymer meets the
requirements, such as the ethylene content and
crystallinity requirements stated herein.
The EAODM interpolymers of this invention
have an ethylene content of at least 84 wt~, preferably
at least 88 wt°s, and more preferably at least 90 wt~,
but in no event more than 99 wto ethylene. The
ethylene content may vary up or down by a few
percentage points depending upon amount and weight of
polyene in the EAODM. In general, choices for amounts
of ethylene, o~-olefin and polyene provide a ratio of
ethylene to oc-olefin of at least 95:5, preferably >
95:5. EAODMs with > 84 wt% ethylene possess a DSC
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crystallinity as described above. It is believed that
this crystallinity provides much of the polymer's
mechanical strength. Polymer crystallinity increases
lead to proportional increases in polymer Tg. The
interpolymers of this invention have a Tg, as measured
by DSC, of >_ -45° Centigrade (°C).,- preferably >_ -
40°C.
Skilled artisans recognize that endothermic melting
peaks obscure Tg as polymer crystallinity increases.
As such, there is no meaningful upper limit for Tg.
The oc-olefin may be either an aliphatic or an
aromatic compound and may contain vinylic unsaturation
or a cyclic compound, such as cyclobutene,
cyclopentene, or norbornene, including norbornene
substituted in the 5 and 6 position with a C1_Zo
hydrocarbyl group. The a-olefin is preferably a C,_Zo
aliphatic compound, more preferably a C,_16 aliphatic
compound and still more preferably a C3_loaliphatic
compound such as propylene, isobutylene, butene-1,
pentene-1, hexene-1, 3-methyl-1-pentene, 4-methyl-1-
pentene, octene-1, decene-1 and dodecene-1. Other
preferred ethylenically unsaturated monomers include 4-
vinylcyclohexene, vinylcyclohexane, norbornadiene, and
mixtures thereof. The most preferred oc-olefins are
propylene, butene-1, hexene-1 and oc_tene-1. The a-
olefin content is preferably from > 0 to < l6wt%, more
preferably from 1 wt~ to 10 wt~, and most preferably
from 2 wt~ to 8 wt°s, based on total interpolymer
weight.
The polyene, sometimes referred to as a
diolefin or a diene monomer, is desirably a CQ_Qo
polyene. The polyene is preferably a nonconjugated
diolefin, but may be a conjugated diolefin. The
nonconjugated diolefin can be a C6_15 straight chain,
branched chain or cyclic hydrocarbon dime.
Illustrative nonconjugated dimes are branched chain
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acyclic dimes such as 2-methyl-1,5-hexadiene, 6-
methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 3,7-
dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene,
5,7-dimethyl-1,7-octadiene, and mixed isomers of
dihydromyrcene; single ring alicyclic dimes such as
1,4-cyclohexadiene, 1,5-cyclooctadiene and 1,5-
cyclododecadiene; multi-ring alicyclic fused and
bridged ring dimes such as tetrahydroindene, methyl
tetrahydroindene, dicyclopentadiene (DCPD), bicyclo-
(2,2,1)-hepta-2, 5-dime (norbornadiene or NBD), methyl
norbornadiene; alkenyl, alkylidene, cycloalkenyl and
cycloalkylidene norbornenes such as 5-methylene-2-
norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-
propenyl-2-norbornene, 5-isopropylidene-2-norbornene,
5-(4-cyclopentenyl)-2-norbornene and 5-cyclohexylidene-
2-norbornene. When the diolefin is a conjugated dime,
it can be 1,3-pentadiene, 1,3-butadiene, 2-methyl-1,3-
butadiene, 4-methyl-1,3-pentadiene, or 1,3-
cyclopentadiene.
The dime is preferably a nonconjugated dime
selected from ENB and NBD, more preferably, ENB. The
EAODM polyene monomer content is preferably within a
range of from > 0 to < 5 mole percent (mold), based on
moles of ethylene, oc-olefin and. On a weight basis,
the EAODM polyene monomer content equates to the mole
-percent limitations and will vary depending upon weight
of the polyene. Broadly speaking, the polyene content
is from > 0 to 15 wt~, more preferably from 0.3 to 12
wt~, and most preferably from 0.5 to 10 wt% based on
interpolymer weight. When the polyene monomer is ENB,
a monomer content of from > 0 to < 11 wto, based on
interpolymer weight, generally equates to the >0 to < 3
molo range.
Molecular weight distribution (MWD) is a
well-known variable in polymers. It is sometimes
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described as the ratio of weight average molecular
weight (Mw) to number average molecular weight (Mn)
(i.e., MW/Mn) and can be measured directly or more
routinely by measuring polymer melt index (I) using
ASTM D-1238 (190°C /10 kilograms (kg)) for Iloand ASTM
D-1238 (190°C /2.16 kg) for I2. and calculating the
Ilo/Iz ratio. Polymers having a narrow MWD exhibit
higher toughness, better optics, and higher crosslink
efficiencies than polymers with the same monomer
composition, but a comparatively broader MWD. The MWD
values of the interpolymers of this invention, prepared
with metallocene catalysts, particularly constrained
geometry catalysts (CGCs), are from > 1 to 15,
preferably from > 1 to 10 and most preferably from > 1
to 4.
The EAODM interpolymers of this invention
have a melting point (mpt) of _> 70°C. The mpt is
desirably >_ 80°C, preferably >_ 85°C. The mpt is
desirably < 135°C, preferably < 125°C. Mpts of < 70°C
effectively exclude certain applications that require a
relatively high upper service temperature (UST) such as
wire and cable jacketing materials with an UST
requirement > 70°C. Skilled artisans recognize that a
theoretical upper melt point limit is established by
HDPE homopolymer with a mpt of approximately 135°C
(varies with polymer molecular weight).
The EAODM interpolymers of this invention
have a heat of fusion > 11 calories per gram (cal/g).
The heat of fusion is desirably > 12 cal/g, and
preferably > 13 cal/g. The heat of fusion may be as
great as 30 cal/g or even higher depending on a variety
of factors, one of which is interpolymer crystallinity.
The EAODM interpolymers of this invention can
be produced using one or more metallocene or
constrained geometry (CGC) catalyst in combination with
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an activator, in solution, slurry, or gas phase
processes. The catalysts are preferably mono- or bis-
cyclopentadienyl, indenyl, or fluorenyl transition
metal (preferably Group 4) catalysts, and more
preferably mono-cyclopentadienyl, mono-indenyl or mono-
fluorenyl CGCs. The solution process is preferred. US
patent 5,064,802; W093/19104 (US serial number 8,003,
filed January 21, 1993), and W095/00526 disclose
constrained geometry metal complexes and methods for
their preparation. Variously substituted indenyl
containing metal complexes are taught in W095/14024 and
W098/49212. The relevant teachings of all of the
foregoing patents and their corresponding US patent
applications are hereby incorporated by reference.
In general, polymerization may be
accomplished at conditions well known in the art for
Ziegler-Natta or Kaminsky-Sinn type polymerization
reactions, that is, temperatures from 0-250°C,
preferably 30-200°C, and pressures from atmospheric to
10,000 atmospheres (1013 megapascals (MPa)).
Suspension, solution, slurry, gas phase, solid state
powder polymerization or other process conditions may
be employed if desired. A support, especially silica,
alumina, or a polymer (especially
poly(tetrafluoroethylene) or a polyolefin) may be
employed, and desirably is employed when the catalysts
are used in a gas phase polymerization process. The
support is preferably employed in an amount sufficient
to provide a weight ratio of catalyst (based on
metal):support within a range of from 1:100,000 to
1:10, more preferably from 1:50,000 to 1:20, and most
preferably from 1:10,000 to 1:30. In most
polymerization reactions, the molar ratio of
catalyst:polymerizable compounds employed is from 10-
12:1 to 10-1:1, more preferably from 10-9:1 to 10-5:1.
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Inert liquids serve as suitable solvents for
polymerization. Examples include straight and
branched-chain hydrocarbons such as isobutane, butane,
pentane, hexane, heptane, octane, and mixtures thereof;
cyclic and alicyclic hydrocarbons such as cyclohexane,
cycloheptane, methylcyclohexane, methylcycloheptane,
and mixtures thereof; perfluorinated hydrocarbons such
as perfluorinated CQ_lo alkanes; and aromatic and alkyl-
substituted aromatic compounds such as benzene,
toluene, xylene, and ethylbenzene. Suitable solvents
also include liquid olefins that may act as.monomers or
comonomers including butadiene, cyclopentene, 1-hexene,
1-hexane, 4-vinylcyclohexene, vinylcyclohexane, 3-
methyl-1-pentene, 4-methyl-1-pentene, 1,4-hexadiene, 1-
octene, 1-decene, styrene, divinylbenzene,
allylbenzene, and vinyltoluene (including all isomers
alone or in admixture). Mixtures of the foregoing are
also suitable. If desired, normally gaseous olefins
can be converted to liquids by application of pressure
and used herein.
The catalysts may be utilized in combination
with at least one additional homogeneous or
heterogeneous polymerization catalyst in the same
reactor or in separate reactors that are connected in
series or in parallel to prepare polymer blends having
desirable properties. An example of such a process is
disclosed in WO 94/00500 at page 29 line 4 to page 33
line 17. The process uses a continuously stirred tank
reactor (CSTR) connected in series or parallel to at
least one other CSTR or tank reactor. WO 93/13143 (at
page 2 lines 19-31) teaches polymerizing monomers in a
first reactor using a first CGC having a first
reactivity and polymerizing monomers in a second
reactor using a second CGC having a second reactivity
and combining the products from the two reactors. Page
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3, lines 25-32 of WO 93/13143 provides teachings about
the use of two CGCs having different reactivities in
one reactor. WO 97/36942 (page 4 line 30 through page
6 line 7) teaches the use of a two loop reactor system.
The relevant teachings of such applications and their
corresponding U.S. patent applications are incorporated
herein by reference. . Additionally, the same catalyst
may be utilized in both reactors operating at different
processing conditions.
The EAODM interpolymers of this invention may
be combined with other natural or synthetic polymers
into a blend that contains from 2 to 98 wto of such
EAODM interpolymer(s) based on total blend weight. The
natural and synthetic polymers can be natural rubber,
styrene-butadiene rubber (SBR), butadiene rubber, butyl
rubber, polyisoprene, polychloroprene (neoprene), or
homopolymers of monoolefins or a mixture of two or more
monoolefins, preferably a CZ_zo a-olefin monomer. The a-
olefin monomer is more preferably selected from the
group consisting of ethylene, propylene-1, butene-1,
hexene-1 and octene-1. Olefin homopolymers or
polyolefins include, for example, polyethylene,
polypropylene, and polybutene. Illustrative copolymers
of two, and interpolymers of at least three, different
monoolefins include ethylene/propylene,
ethylene/butene, ethylene/hexene and ethylene/octene
copolymers, ethylene/propylene/carbon monoxide
polymers, ethylene/styrene interpolymers, and
ethylene/vinyl acetate copolymers. The EAODM
interpolymers of this invention may also be blended
with conventional ethylene/propylene/diene monomer
(EPDM) or EAODM interpolymers that have an ethylene
content _< 80 wt~. The preferred polyolefins for
blending with interpolymers of this invention
polyethylene (PE), polypropylene (PP) and blends
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thereof. The term "PE" includes HDPE, low density
polyethylene (LDPE), linear low density polyethylene
(LLDPE), medium density polyethylene (MDPE), and ultra
low density polyethylene (ULDPE).
The interpolymers of this invention and
blends thereof can be crosslinked or cured using
conventional procedures and compounds.
Suitable peroxides for crosslinking or curing
include a series of vulcanizing and polymerization
agents that contain oc, a'-bis(t-butylperoxy)-
diisopropylbenzene and are available from Hercules,
Inc. under the trade designation WLCUPTM, a series of
such agents that contain dicumyl peroxide and are
available from Hercules, Inc. under the trade
designation Di-cupTM as well as LupersolTM peroxides
made by Elf Atochem, North America and TrigonoxTM
organic peroxides made by Moury Chemical Company. The
LupersolTM peroxides include LupersolTM 101 (2,5-
dimethyl-2,5-di(t-butylperoxy)hexane), Luperso1TM130
(2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3) and
Luperso1TM575 (t-amyl peroxy-2-ethylhexonate). Other
suitable peroxides include 2,5-dimethyl-2,5-di-(t-butyl
peroxy)hexane, di-t-butylperoxide, 2,5-di(t-amyl
peroxy)-2,5-dimethylhexane, 2,5-di-(t-butylperoxy)-2,5-
diphenylhexane, bis(alpha-methylbenzyl)peroxide,
benzoyl peroxide, t-butyl perbenzoate and bis(t-
butylperoxy)-diisopropylbenzene.
The peroxide can be added by any conventional
means known to skilled artisans. If processing oil is
used in preparing polymer blends and other compositions
that include an EAODM interpolymer of the invention,
the peroxide may be injected during processing of the
blend or composition as a solution or dispersion in the
processing oil or another dispersing aid. The peroxide
can also be fed into a processing apparatus at a point
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where the polymer blend or composition is in a melt
state. Concentrations of peroxide in a solution or
dispersion may vary over a wide range, but a 20 to 40
wto concentration, based on solution or dispersion
weight, provides acceptable results. The solution or
dispersion can also be admixed with, and allowed to
imbibe on, dry and dry blended polymer pellets. If the
peroxide is a liquid, it may be used as is without
first preparing a solution or dispersion in, for
example, a processing oil. In other words, one can add
a liquid peroxide to a high speed blender together with
dry polymer pellets, subject the blender contents to
mixing action for a short period of time and then allow
the contents to rest until imbibing action is regarded
as sufficiently complete. One may regard the absence
of a separate, discernible liquid peroxide fraction as
being sufficiently complete. On a small scale, mixing
occurs in a Welex Papenmeier Type TGAHK20 blender
(Papenmeier Corporation) for a period of 30-45 seconds,
followed by a rest period of 30 minutes. A more
preferred procedure involves introducing the peroxide
as a solid into a compounding apparatus together with
polymer pellets as the pellets enter a compounding
apparatus such as at the throat of an extruder. An
alternate preferred procedure includes a step of adding
the peroxide to a polymer melt in a compounding
apparatus such as a Haake, a Banbury mixer, a Farrel
continuous mixer or a Buss kneader. One can also
introduce a previously formed dry blend of a solid
peroxide and polymer pellets to the apparatus. The
peroxide is suitably present in an amount within a
range of from 0.05 to 10 wto, based upon total weight
of polymer in the blend or composition. Low levels of
peroxide may show no measurable gel content as measured
by boiling xylene extraction, but will still evidence
discernible rheology improvements relative to the same
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composition save for the peroxide. In other words, the
amount of peroxide should be sufficient to effect at
least partial crosslinking of the EAODM interpolymers
of this invention. A peroxide content in excess of 10
wto tends to yield materials that are too brittle for
practical use.
For efficient peroxide crosslinking, a sample
needs to be subjected to heat for a time sufficient to
decompose the peroxide thus generating free radicals
for crosslinking. Depending on the peroxide,
crosslinking can be initiated a temperatures ranging
from 70°C to 80°C for a low temperature peroxide to as
high as 220°C to 230°C using a high temperature
peroxide. The crosslinking time can vary from as
little as a few minutes to as long as 30 minutes. One
skilled in the art can determine the required time and
temperature for peroxide crosslinking based on known
half-life temperature data for different peroxides.
Sulfur and phenolates (alkylphenol
formaldehyde resins) and silicon hydrides serve as
functional alternatives to peroxides. Sulfur produces
satisfactory results at levels of 1-8 wt~, based on
total weight of polymer in the blend or composition.
Phenolates such as 2,6-dihydroxymethyl alkylphenol also
produce satisfactory results at levels of 1-15 wt~,
based on total weight of polymer in the blend or
composition. Silicon hydrides produce satisfactory
results at levels of 1-10%, based on total weight of
polymer in the blend or composition.
As noted above, crosslinking may also occur
via EB irradiation. One advantage of using EB
irradiation is that, if desired, a crosslinked polymer
system with at least partial crosslinking of the EAODM
interpolymers of the present invention can be made
without using peroxide or any other crosslinking
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additives. Suitable doses of EB irradiation range from
0.1 megarad (Mrad) to 30 Mrad, preferably from 0.1 Mrad
to 10 Mrad, more preferably from 0.1 Mrad to 8 Mrad,
and most preferably from 0.1 Mrad to < 5 Mrad. While
one may use a dosage in excess of 30 Mrad, e.g. 70
Mrad, doing so simply increases cost without providing
sufficient offsetting physical property improvements to
justify the increased cost. The actual irradiation
dose required depends upon several variables including
the source and intensity of the irradiation, the
polymer being crosslinked, the thickness of. the
material or article, and environmental and other
factors. The preferred source of irradiation is a high
energy beam from an electron accelerator. High energy
beams give an adequate curing dosage and rates of
processing as high as 1200 meters per minute. Various
types of high power electron linear accelerators are
commercially available. Since the radiation levels
required to accomplish crosslinking in EAODMs of the
present invention are relatively low, small power
units, such as the Electrocurtain~ Processor from
Energy Sciences, Inc., Wilmington, Mass., provide
sufficient radiation. As noted above, other sources of
high energy radiation, such as gamma rays may also be
used.
Crosslinking may additionally occur via W
irradiation. In this embodiment the interpolymer
composition of this invention may, preferably, contain
at least one photoinitiator agent. Suitable
photoinitators include, but are not limited to,
benzophenone, ortho- and Para-methoxybenzophenone,
dimethylbenzophenone, dimethoxy- benzophenone,
diphenoxybenzophenone, acetophenone, o-methoxy-
acetophenone, acenaphthenequinone, methyl ethyl ketone,
valerophenone, hexanophenone, (x- phenyl-butyrophenone,
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p-morpholinopropiophenone, dibenzosuberone, 4-
morpholinobenzophenone, benzoin, benzoin methyl ether,
3-o morpholinodeoxybenzoin, p-diacetylbenzene, 4-
aminobenzophenone, 4'- methoxyacetophenone, (x-
tetralone, 9-acetylphenanthrene, 2-acetyl-
phenanthrene, I 0-thioxanthenone, 3-acetyl-
phenanthrene, 3-acetylindole, 9-fluorenone, I -
indanone, 1,3,5-triacetylbenzene, thioxanthen-9-one,
xanthene=9-one, 7-H- benzfde]anthracen-7-one, benzoin
tetrahydrophyranyl ether, 4,4'- bis(dimethylamino)-
benzophenone, F-acetonaphthone, 2'acetonaphthone,
acetonaphthone and 2,3-butanedione, benz[alanthracene-
7,12-dione, 2,2- dimethoxy-2-phenylacetophenone, (x,(x-
diethoxy-acetophenone, cw- dibutoxyacetophenone,
anthraquinone, isopropylthioxanthone and the like.
Polymeric initiators include poly(ethylene/carbon
monoxide), oligo[2- hydroxy-2- methyl-1-(4-(1-
methylvinyl)phenyllpropanone], polymethylvinyl ketone,
and polyvinylaryl ketones. Use of a photoinitiator is
preferable in combination UV irradiation because it
generally provides faster and more efficient
crosslinking.
Preferred photoinitiators that are commercially
available include benzophenone, anthrone, xanthone, and
others, the IrgacureTM series of photoinitiators from
Ciba-Geigy Corp., including 2,2-dimethoxy-2-
phenylacetophenone (Irgacure 65 1); 1 -
hydroxycyclohexylphenyl ketone (Irgacure 184) and 2-
methyl- 1-[4-(methylthio)phenyll-2-moropholino propan-
I - one (Irgacure 907). The most preferred
photoinitiators will have low migration from the
formulated resin, as well as a low vapor pressure at
extrusion temperatures and sufficient solubility in the
polymer or polymer blends to yield good crosslinking
efficiency. The vapor pressure and solubility, or
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polymer compatibility, of many familiar photoinitiators
can be easily improved if the photoinitiator is
derivatized. The derivatized photoinitiators include,
for example, higher molecular weight derivatives of
benzophenone, such as 4- phenylbenzophenone, 4-
aflyloxybenzophenone, 4-dodecyloxybenzophenone and the
like. The photoinitiator can be covalently bonded to
the interpolymer of this invention or to a polymer
diluent, as described herein below. The most preferred
photoinitiators will, therefore, be substantially non-
migratory from the polymeric material.
The radiation should be emitted from a source
capable of emitting radiation of the wavelength of from
170 to 400 manometers (mm). The radiation dosage should
be at least 0. 1 Joule per cm2 (J/ cmz) and preferably
from 0.5 to 10 (J/ cm2) and most preferably from 0.5 to
about 5 (J/ cm2). The dosage required on a particular
application will depend on the configuration of the
layer in the film, the composition of the layer, the
temperature of the film being irradiated and the
particular wavelength used. The dosage required to
cause crosslinking to occur for any particular set of
conditions can be determined by the artisan.
European Patent Application 0 490 854 A2 teaches a
continuous process for crosslinking polyethylene with
W light.
The EAODM interpolymers of this invention may
be modified by or grafted with other monomers. Any
unsaturated compound that is organic and contains at
least one ethylenic unsaturation (e.g., at least one
double bond) and at least one carbonyl group (--C=O)or
is an unsaturated alkoxysilane, and that will graft to
an EAODM interpolymer can be used. The grafted
16
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interpolymers can be blended with other natural or
synthetic polymers in the same manner as ungrafted
EAODM interpolymers.
Monomers that are suitable for grafting or
modification include unsaturated carboxylic acids, as
well as anhydrides, esters and salts, both metallic and
nonmetallic, of such acids and unsaturated
alkoxysilanes. The unsaturated carboxylic acid
monomers preferably contain ethylenic unsaturation that
is conjugated with a carbonyl group. These acids
include, for example, malefic acid, fumaric acid,
acrylic acid, methacrylic acid, itaconic acid, crotonic
acid, alpha-methyl crotonic acid, and cinnamic acid.
The unsaturated alkoxysilanes include, for example,
vinyltrimethoxysilane and vinyltriethoxysilane. The
monomer is most preferably malefic anhydride.
The grafted EAODM interpolymers have a
minimum unsaturated compound or grafted monomer content
of >_ 0.01 wt %, and preferably >_ 0.05 wt %, based on
grafted EAODM interpolymer weight. The unsaturated
compound content can vary upward from the minimum
according to convenience, but is typically <_ 10 wt%,
and is preferably <_ 5 wt%, more preferably <_ 2 wt%
based on grafted EAODM interpolymer weight.
The unsaturated compound can be grafted to
the EAODM interpolymer by any known technique, such as
those taught in U.S. Pat. No. 3,236,917 and U.S. Pat.
No. 5,194,509, the relevant teachings of which are
incorporated into and made a part of this application
by reference. For example, in the '917 patent, the
polymer is introduced into a two-roll mixer and mixed
at a temperature of 60°C. The unsaturated organic
compound is then added along with a free radical
initiator, such as, benzoyl peroxide, and the
components are mixed at 30°C until the grafting is
17
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complete. In the '509 patent, the procedure is similar
except that the reaction temperature is higher, e.g.,
210° to 300°C., and a free radical initiator is not
used or is used at a reduced concentration.
An alternative and preferred method of
grafting is taught in U.S. Pat. No. 4,950,541, the
relevant parts of which are incorporated into and made
a part of this application by reference. The '541
patent teaches, at column 4, lines 16 through 28, use
of a twin-screw devolatilizing extruder as a mixing
apparatus. When using such an apparatus, the EAODM
interpolymer and the unsaturated compound are suitably
mixed together and reacted within the extruder at
temperatures above the EAODM interpolymer mpt and in
the presence of a free radical initiator. The
unsaturated compound is preferably injected into molten
EAODM within an extruder zone that is maintained under
pressure.
In another embodiment of this invention, the
graft-modified EAODM interpolymer is dry blended or
melt blended with another thermoplastic polymer, and
then molded or extruded into a shaped article. Such
other thermoplastic polymers include any polymer with
which the grafted EAODM interpolymer is compatible, and
include both olefin and non-olefin polymers and
engineering thermoplastics, as well as grafted and
ungrafted versions of such polymers. The amount of
graft-modified EAODM interpolymer that is blended with
one or more other polymers varies and depends upon many
factors, including the nature of the other polymer(s),
the intended end use of the blend, the presence or
absence of additives and, if present, the nature of
such additives. In those applications in which the
grafted ethylene interpolymer is blended with other
polyolefin polymers, e.g. a non-grafted ethylene
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interpolymer or a conventional polyolefin polymer
(LLDPE, HDPE, PP), the blend composition comprises <_
70 wt % graft-modified ethylene interpolymer(s),
preferably <_ 50 wt%, and most preferably _< 30 wt %,
based on total weight of blended polymers. The
presence of the graft-modified EAODM interpolymer in
these blends, both for engineered materials and wire
and cable compositions, provides impact and/or strength
properties to the materials and compositions.
In other embodiments, the graft-modified
EAODM interpolymer comprises from a relatively minor
amount (e. g. 10 wt%), up to 100 wt % of the finished
article. In those applications in which paintability
of a finished article is important, a graft-modified
EAODM interpolymer content within a range of 10 to 50
wt %, based on the total weight of the finished
article, provides satisfactory results relative to an
otherwise unpaintable molded article, e.g. an article
prepared from a polyolefin such as polyethylene,
polypropylene, etc. A graft-modified EAODM
interpolymer content of < 10 wt% provides little or no
benefit in terms of improving polyolefin paintability.
Conversely, while graft-modified EAODM contents of > 50
wt%, e.g. >_ 70 wt%, may be used, finished article
properties such as flex modulus may be unacceptably low
while others such as heat distortion may be too high
relative to articles prepared without the graft-
modified EAODM interpolymer.
The EAODM interpolymers of this invention,
whether graft-modified or not and whether blended with
other polymers or not, may be compounded with any one
or more of materials conventionally added to polymers.
These materials include, for example, process oils,
plasticizers, specialty additives and pigments. These
materials may be compounded with such EAODM
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interpolymers or blends containing the same either
before or after EAODM interpolymer crosslinking occurs.
Selection of such materials and addition of the same to
EAODM interpolymers and compounds including such
interpolymers lies well within a skilled artisan's
competence.
Process oils are often used to reduce any one
or more of viscosity, hardness, modulus and cost of a
composition. The most common process oils have
particular ASTM designations depending upon whether
they are classified as paraffinic, naphthenic or
aromatic oils. An artisan skilled in the processing of
elastomers in general and EAODM compositions in
particular will recognize which type of oil will be
most beneficial. A useful amount of process oil lies
within a range of from > 0 to 200 parts by weight, per
100 parts by weight of EAODM interpolymer.
A variety of specialty additives may be
advantageously blended with interpolymers of this
invention to prepare useful compositions of matter.
The specialty additives include antioxidants; surface
tension modifiers; anti-block agents; lubricants;
antimicrobial agents such as organometallics,
isothtazolones, organosulfurs and mercaptans;
antioxidants such as phenolics, secondary amines,
phophites and thioesters; antistatic agents such as
quaternary ammonium compounds, amines, and ethoxylated,
propoxylated or glycerol compounds; fillers and
reinforcing agents such as carbon black, glass, metal
carbonates such as calcium carbonate, metal sulfates
such as calcium sulfate, talc, clay or graphite fibers;
hydrolytic stabilizers; lubricants such as fatty acids,
fatty alcohols, esters, fatty amides, metallic
stearates, paraffinic and microcrystalline waxes,
silicones and orthophosphoric acid esters; mold release
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agents such as fine-particle or powdered solids, soaps,
waxes, silicones, polyglycols and complex esters such
as trimethylolpropane tristearate or pentaerythritol
tetrastearate; pigments, dyes and colorants;
plasticizers such as esters of dibasic acids (or their
anhydrides) with monohydric alcohols such as o-
phthalates, adipates and benzoates; heat stabilizers
such as organotin mercaptides, an octyl ester of
thioglycolic acid and a barium or cadmium carboxylate;
ultraviolet light stabilizers used as a hindered amine,
an o-hydroxy-phenylbenzotriazole, a 2-hydroxy,4-
alkoxyenzophenone, a salicylate, a cynoacrylate, a
nickel chelate and a benzylidene malonate and
oxalanilide; and zeolites, molecular sieves and other
known deodorizers. A preferred hindered phenolic
antioxidant is Irganox TM 1076 antioxidant, available
from Ciba-Geigy Corp. Each of the above additives, if
used, is present in an amount of from > 0 to <_ 45 wt~,
based on total composition weight, desirably from 0.001
to 20 wt~, preferably from 0.01 to 15 wto and more
preferably from 0.1 to 10 wt~. While more than one
specialty additive may be present, amounts of each
additive are selected to yield a total additive content
of <_ 90 wt~, based on total composition weight.
The EOADMs of this invention or blends
thereof with other polymers may be compounded with one
or more other materials and additives and fabricated
into a variety of shapes including, without limitation,
extruded profiles, parts, sheets, belts, wire and cable
insulation, foams, shrink tubing and films using any
one of a number of conventional procedures for
processing thermoplastic or thermoset elastomers. The
EAODMs, blends and resulting compounds can also be
formed, spun or drawn into films, fibers, multi-layer
laminates or extruded sheets, coatings or thin layer
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co-extruded sheets, or compounded with one or more
organic or inorganic substances, on any machine
suitable for such purposes. Any of the above shapes
may be multi-layered.
The following examples illustrate but do not,
either explicitly or by implication, limit the present
invention. Unless otherwise stated, all parts (pbw)
and percentages (wt~) are by weight, on a total weight
basis. Examples (Ex.) of the present invention are
identified by Arabic numerals and letters of the
alphabet identify comparative examples (Comp. Ex.)
EXPERIMENTAL
Ex. 1-4 and Comp. Ex. A-D
Polymer Preparation
Examples 1-4, Interpolymers of this
invention and Comparative Example A were prepared using
a 3.8 liter (1) stirred reactor providing for
continuous addition of reactants and continuous removal
of polymer solution, devolatilization, and polymer
recovery. The catalyst system was a (t-butylamido)-
dimethyl(~5-2-methyl-s-indacen-1-yl)silanetitanium (II)
1,3-pentadiene CGC, a tris(pentafluorophenyl)borane
(FAB) co-catalyst and a modified methylalumoxane (MMAO)
scavenging compound. Tables 1D to 4 show physical
properties for Examples 1-4 and Comparative Example A.
Ethylene (C2), propylene (C3), and hydrogen
(HZ) were combined into one stream before introducing
the stream into a diluent mixture comprising a mixed
alkane solvent (Isopar-ETM, available from Exxon
Chemicals Inc.) and polyene (ENB) to form a combined
feed mixture. The combined feed mixture was
continuously injected into a reactor. The catalyst
(Cat) and a blend of the cocatalyst (Cocat) and
scavenging compound (Scav) were combined into a single
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stream, which was continuously injected into the
reactor.
Table IA shows flow rates for solvent, C2, C3,
and ENB in pounds per hour (phr). Table IB shows
concentrations and flow of Cat, Cocat and Scav in parts
per million (ppm) and pounds per hour (phr),
respectively. Table 1B also shows Cocat/Cat and
Scav/Cat ratios. Table IC shows hydrogen flow, in
standard cubic centimeters per minute (sccm), amount of
polymer produced in phr, Reactor Temperature (Temp) in
°C, and Reactor Pressure in megapascals (MPa).
A reactor exit stream was continuously
introduced into a separator to continuously separate
molten polymer from the solvent and unreacted C2, C3, HZ
and ENB. The molten polymer was cooled in a water bath
or pelletizer, the cooled polymer was strand chopped or
pelletized and the resulting solid pellets were
collected.
TABLE 1A
Monomer
and Solvent
Flo~fs
(phr)
Solvent
Example Flow Ethylene Propylene ENB
Flow Flow Flow
A 36.9 4.5 2.37 0.60
1 38.9 4.7 0.86 0.41
2 38.9 4.7 0.82 0.04
3 38.9 4.5 0.44 0.34
4 31.2 4.0 0.41 0.03
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Table
18
Catalyst
Compoaent
Flows
Ex Cat Cat Cocat Cocat Scav Scav Coca/ Scav/
&
Comp Conc Flow Conc Flow Conc. Flow Cat Cat
Ex. (ppm)(phr) (ppm) (phr) (ppm) (phr) Ratio Ratio
(Boro (A1/Ti)
n/Ti)
A 19.9 0.261 950 0.176 64 0.18 3 3.9
1 11.5 0.641 4611 0.513 43 0.58 3 6
2 11.8 0.494 461 0.405 43 0.46 3 6
3 24.7 0.546 965 0.448 75 0.61 3 6
4 24.7 0.441 965 0.362 75 0.49 3 6
Table 1C
Reactor
Conditions
Ex. and Hz Flow Polymer Reactor Reactor
Comp. Ex. (sccm) ProductionTemp. Pressure
( hr) (C) (MPa)
A 52 4.21 121 3.102
1 106 5.00 120 2.103
2 92 4.05 121 2.344
3 260 3.82 130 2.985
4 286 3.42 130 2.841
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Table
1D
Composition
Data
Ex. And C2 C2 C, C3 ENB C2/C,
Comp. (wt~) (mold)(wt~) (mold)*(wt~) wt.
Ex. * Ratio
1 84.9 92.7 9.9 7.3 5.2 8.58
2 85.3 90.5 13.4 9.5 1.3 6.37
3 88.7 95.5 6.2 4.5 5.1 14.3
4 94.1 96.9 4.6 3.1 1.3 20.5
A 72.1 82.8 22.4 17.2 5.5 3.2
*Based only on CZ and C3 content
Table 2
Gel Permeation
Chromatography
(GPC) Data
Ex. And Mw Mn MWD (Mw/Mn)
Com . Ex.
1 117,500 57,100 2.06
2 115,600 53,200 2.17
3 110,900 49,500 2.24
4 119,700 56,500 2.12
A 138,100 68,500 2.02
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Table
3
Deasity
aad
Thermal
property
Data
Ex. DensityCrystallizationPeak Crystal-Heat Heat Tg*
and (g/cc) Onset (C) Meltinglinityof of (C)
Comp. Point (~) Fusion Fusion
Ex. (C) (joules/(calories
ram) / ram)
1 0.899 64.7 72.6 19.6 57.2 13.7 -20.1
2 0.898 73.0 80.5 20.5 59.9 14.3 -27.9
3 0.909 80.0 87.3 26.8 78.3 18.7 -20.0
4 0.916 96.1 105.5 39.9 116.5 27.8 -22.5
A 0.881 35.9 45.5 15.5 45.3 10.8 -35.0
Table
4
Physical
Property
Data
Ex. Tensile Tensile ElongationElongationMooney
& @Yield @ Break @ Yield @ Break Viscosity*
Comp. (MPa) (MPa) (~)
Ex.
1 2.91 21.7 31 575 30.7
2 3.41 12.4 20 686 29.2
3 4.1 23.0 19 579 29.5
4 8.41 16.7 17 756 30.2
A 1.5 9.3 34 718 41.3
* Measured in accordance with ASTM D1646 (ML1~4 at
125°C)
Irradiation Trials
Using EB irradiation, the(a) interpolymers of
Ex 1-4 and (b) polymers of Comp. Ex. B-D were
crosslinked. Comp. Ex. B is an elastomeric
ethylene/octene copolymer (Engage~ 8003 available from
DuPont Dow Elastomers L.L.C.) with a density of 0.885
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grams per cubic centimeter (g/cc), a melt index (MI) or
IZ of 1 decigram per minute (dg/min), a GPC molecular
weight (MW) of 125,000, and a MWD of 2Ø Comp. Ex. C
is a LLDPE ( an ethylene/octene copolymer available
from The Dow Chemical Company as Dowlex 2045) with a
density of 0.92 g/cc, a MI or IZ of 1 dg/min, a GPC
molecular weight (MW) of 110,000, and a MWD of 4Ø
Comp. Ex. D is an ethylene-vinyl acetate (EVA)
copolymer (Elvax~ 460 available from E. I. du Pont de
Nemours and Company) with a density of 0.941 g/cc, a MI
of 2.5 dg/min, a GPC molecular weight (MW) of 80,000, a
MWD of 5, and a vinyl acetate content of 18 wta. MI
measurements employ ASTM D1238 at 190°C or a modified
version thereof (for the EVA copolymers).
Two identical sets of plaques were prepared
from each of Ex. 1-4 and Comp. Ex. B-D. The plaques
were compression molded to a thickness of 0.125 inch
(0.32 centimeter (cm)) using the following cycle: heat
at 190°C for three minutes with no pressure; apply a
pressure of 18,200 kg while maintaining the temperature
at 190°C; water cool to ambient temperature (about 25°C)
while maintaining the 18,200 kg pressure; and release
the pressure. One set of seven plaques was used as a
control (without irradiation); the other set of seven
plaques were EB irradiated at a dosage of 2 Mrad. The
data in Table 5 compare the irradiated and non-
irradiated plaques.
Hot creep was measured as described in
Insulated Cable Engineers Association Publication T-28-
562, Published 3/81, revised 1/83. The hot creep test
involves hanging a weight on a dumbbell test specimen
to yield a stress of 29 pounds per square inch (psi)
(200 kilopascals (kPa)) in an oven heated to 200°C. At
low levels of crosslinking in the specimen, the
specimen elongates up to 600 and then bottoms out in
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the oven. As used in Table 5 below, "Failed" means
that the sample in question bottomed out in the oven.
At higher levels of crosslinking, the specimen displays
less elongation and provides a measurable percentage
elongation. "Hot" creep measurements provide an
indication of the degree of crosslinking as hot creep
and degree of crosslinking are inversely related. In
other words, a decrease in hot creep value equates to
an increase in the degree of crosslinking. The
insoluble gel fraction (gel content) was measured as
described in ASTM D 2765 using hot xylene as the
solvent.
Table
5
Comparison
of
Plague
Properties
(Irradiated
Vs
Noa-irradiated)
Ex. IrradiatedIrradiatedNon- Non-
~d Hot Creep Irradiated Irradiated
~ Gel
Comp. ~~~ ~ Gel Hot Creep
Ex.
B
<3 Failed <3 Failed
C <3 - <3 Failed
D 54.2 Failed <3 Failed
1 81.9 220 <3 Failed
2 38.9 Failed <3 Failed
3 84.7 218 <3 Failed
4 81.8 525 <3 Failed
- means not measured
The data in Table 5 show that the EAODM
interpolymers of Examples 1-4 have a higher cross-
linking response to EB irradiation (i.e. more
efficiently cross-linked as indicated by o gel) than
the polymers of Comp. Ex. B and C. With one exception
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(Ex 2), the EAODM polymers provide acceptable hot creep
performance.
A theoretical explanation of the differences
between Ex 2 and Ex 4 builds upon a base established by
the difference in crystallinity prior to crosslinking.
The interpolymer of Ex. 2 has a crystallinity of 20.5
whereas the interpolymer of Ex. 4 has a crystallinity
of 39.9. As noted in the Radiation Technolocty
Handbook, Richard Bradley, Marcel Dekker, Inc., 1984 at
page 106, EB curing tends to occur in non-crystalline
regions of a polymer. ENB , due to its large size
relative to Cz and the o~-olefin monomers, appears to
reside in amorphous or non-crystalline regions of the
EAODM polymers. As such, even with equal percentages
of ENB, a more highly crystalline polymer (e.g. Ex. 4
relative to Ex. 2) should provide a greater
concentration of ENB in its amorphous regions. This
may, in turn, yield a higher potential for
crosslinking. As noted above, an increase in
crosslinking leads to a reduction in elongation in hot
creep testing. In view of a relatively lower
crosslinking potential, one means of improving the hot
creep test results of the Ex. 2 interpolymer involves
increasing the radiation dosage from 2 Mrad to a level
of >_ 4 Mrad.
EXAMPLES 5-8
Four sample compositions, Ex. 5-8 ,
respectively, were prepared from the interpolymers of
Ex.1 to 4 by blending each EAODM interpolymer with 2
wt~ Lupersol~ 130 peroxide (2,5-Dimethyl-2,5
dibutylperoxy hexyne-3 available from Elf Atochem)
using a 200 gram (g) Haake mixer. The blends were
prepared at a temperature of 130° C by mixing for 4
minutes at a rotor speed of 20 revolutions per minute
(rpm). After preparing the four sample compositions,
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each composition was pressed into a 0.32 cm plaque for
curing trials using a modified procedure. The modified
procedure employed the following cycle: heat at 130°C
for two minutes while applying a pressure or force of
18,200 kg; water cool to ambient temperature (about
25°C) over a period of three minutes while maintaining
the 18,200 kg pressure; and release the pressure. A
sample from each uncured plaque was saved for
oscillating disk rheometer (ODR) testing in accordance
with American Society for Testing and Materials (ASTM)
test D-2084. The plaques were cured using the following
cycle: heat at 180°C under an applied force of 18,200
kg for 20 minutes; cool to ambient temperature over a
three minute period while maintaining the 18,200 kg
applied force; and release the applied force. The
percent gel analysis and hot creep elongation were
determined (See Table 6). See Table 7 for ODR data.
Plaques prepared from the interpolymers of Ex. 1-4, but
no peroxide, have less than 2o gel and fail the hot
creep test.
Table 6 Plaaue Properties
Example Crosslinked Crosslinked
with Peroxide with Peroxide
oGel Hot Creep
5 98.5 21.9
6 98.4 15.6
7 97.5 36.6
8 97.5 39.8
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Table
7
ODR Data
at 180C
Example Minimum Maximum D T2 T90
Tor a Tor a Tor a (min.) (min.)
0.097 1.081 0.984 0.58 8.54
6 0.107 1.266 1.159 1.10 11.11
7 0.108 1.370 1.262 1.10 11.31
8 0.120 1.416 1.296 1.22 13.40
Torque
values
in kilograms-meter
ODR was
determined
usin
ASTM
D-2084
The results shown in Tables 6 and 7 confirm
that EAODM polymers of this invention can be cross-
5 linked using peroxides. The ODR data show that an
increase in EAODM polymer ethylene content results in a
higher delta (0) torque value. (See Table 1 for
ethylene contents.) Skilled artisans recognize that an
increase in O torque value corresponds to an increase
in the degree of crosslinking. This allows one to use
a lower level of peroxide to obtain a desired degree of
crosslinking than that required for EAODM polymers with
a lower ethylene content. Higher crosslinking can be
obtained with less peroxide which is an expensive
component, thus allowing the end user to obtain similar
crosslink density at a lower cost. By way of contrast,
conventional EAODM polymers prepared from the same
monomers, but with an ethylene content of 80 wt~ or
less, should yield lower O torque values and require
correspondingly greater amounts of peroxide to attain
the same crosslink level.
Examples 9-10 and Comp. Ex. E
The sampled composition of Ex. 9 was prepared
from a blend of 90 wto of the Comp. Ex. C polymer and
10 wt~ Ex. 1. The sample composition of Ex. 10 was
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prepared from a blend of 70 wt~ of the Comp. Ex. C
polymer and 30 wto Ex. 1. 100 wt~ of the Comp. Ex. C
polymer was used as a control and designated as Comp Ex
E. The blends were prepared by tumble dry blending
polymer pellets, melt compounding the dry blended
pellets in a Leistriz Micro 18 millimeter (mm) co-
rotating twin screw extruder with Haake 9000 torque
rheometer drive to provide an extruded rod. The
extrusion conditions are shown in Table 8 below:
Table 8
Extrusion Conditions
for Compounding
Ex. 9-
10 and Comp.
Ex. E
Heater Zone Temperature
Location
Feed Zone ( C )
Water
Jacketed
Zone 1 190
Zone 2 190
Zone 3 190
Zone 4 190
Zone 5 190
Zone 6 190
Die Zone 190
Screw S eed 60 r m
Output Rate 1.36
k /hr
The extruded rod was cooled in a water bath
and the cooled rod was pelletized. Plaques were
prepared using the procedure described above in Ex. 1-
4. One plaque of each example was EB irradiated at a
dosage of 1 Mrad and one plaque from each example was
EB irradiated at a dosage 2 Mrad using a ten megavolt
(MeV) EB unit. One plaque from each example free of
irradiation exposure was saved for use as a control.
The degree of crosslinking was used as in Examples 1-4.
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Table 9
Comparison
of Plaque
Properties
(Irradiated
vs.
Non-Irradiated)
Ex. And Irradiated Irradiated Non-
Comp. Ex. at 1 Mrad at 2 Mrad Irradiated
(o Gel) (o Gel) at 0 Mrad
Gel)
E <3 <3 <3
9 35.6 58.0 <3
59.3 67.0 <3
The results in Table 9 demonstrate that the
addition of 10-30 wt~ of an EAODM interpolymer
representative of the present invention can boost the
gel response (degree of crosslinking) to EB irradiation
5 in LLDPE (Comp. Ex. E). The gel levels for the
compositions of Exs. 9 and 10 at a 1 Mrad dose and Ex 9
at a 2 Mrad dose fall within a 20-60 wt~ gel content
range preferred for free rise foam expansion. Gel
levels of 30-40 wt% are more preferred. (Reference:
10 Polymeric Foams, D. Klempner and K. Frish, ed., Chapter
9, pp. 201-203, Hanser Publishers, 1991). An increase
in gel response at a low EB dosage, such as 1 Mrad,
should significantly increase the capacity of existing
EB units. Skilled artisans can readily determine
optimal levels of EAODM and radiation dosage for LLDPE
and other polymers disclosed herein.
Example 11 and Comp. Ex. F-G
Comp. Ex. F, which contains 100 wt~ propylene
copolymer ( ProfaxTM 8623 , commercially available from
Himont with a melt flow rate (ASTM D 1238) of 2, a
density of 0.9 g/cc (ASTM D 792A-2) and a flexural
modulus (ASTM D 790B) of 140,000 psi (965 MPa)), was
used as a control. The compositions of Comp. Ex. G and
Ex. 11 each contain 70 wt~ of the Comp. Ex. F copolymer
and 30 wt~ of a second polymer (the copolymer of Comp.
Ex. C. for Comp. Ex. G and the interpolymer of Ex. 1
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for Ex. 11). Test plaques were prepared using the
procedure of Ex. 1-4. One set was retained as a control
(no irradiation) and the remaining sets were exposed to
respective EB irradiation dosages of 2, 5, and 10
Mrads. The gel content was determined using the
procedure described in Ex. 1-4. Table 10 summarizes
the gel test results.
Table
Comparison
of
Plaque
Properties
(Irradiated
vs.
Non-Irradiated)
Ex. Irradiated Irradiated Irradiated Non-
And at 2 Mrad at 5 Mrad at 10 Mrad Irradiated
Comp. (~ Gel) (~ Gel) (~ Gel) at 0 Mrad
Ex. (~ Gel)
F <3 <3 <3 <3
G <3 21.2 31.5 <3
11 31.4 37.4 44.9 <3
10 The copolymer of Comp. Ex. F in Table 10
shows no gel response to e-beam irradiation.
Polypropylenes are known to undergo chain scissioning
rather than crosslinking under EB irradiation.
(Reference: Radiation Technoloay Handbook, at pages
114-129). The composition of Comp. Ex. G exhibits some
irradiation response, but at 5-10 Mrad of dosage. On
the other hand, the sample composition of Ex. 11
exhibits an irradiation response at 2 Mrad dosage
comparable to that of the Comp. Ex. G composition at 10
Mrad. Other EAODMs that represent the present
invention, when combined with the polypropylene of Ex
11 or with other polymers disclosed herein, should
yield similar results.
Exam 1e 12 and Comp. Example H
Table 11 summarizes flexural modulus (ASTM D-
790) and tensile/elongation (ASTM D-638) properties for
34
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the interpolymers of Comp. Ex. A and Ex 3, and the
compositions of Comp. Ex. H and Ex. 12. The sample
compositions for Comp. Ex. H and Ex. 12, respectively,
were prepared by blending 30 wt~ of the Comp. Ex. A
interpolymer and the Ex. 3 interpolymer with 70 wto of
the Comp. Ex. C copolymer using the apparatus and
process of Ex. 5-8 save for increasing the time to 5
minutes, the temperature to 190° C and the rotor speed
to 40 rpm. The interpolymers of Comp. Ex. A and Ex. 3,
and the compositions of Comp. Ex. H and Ex. 12 were
converted into test plaques using the procedure of Ex.
1-4 and the plaques were subjected to flexural modulus
and tensile/elongation testing.
Table 11
Physical Property
Comparison
of Comp.
Ex. H and
Ex. 12 (Uncured
System)
Property Comp. Comp. Ex. 3 Ex. 12
(units) Ex. A Ex. H
Flex 12.7 100.6 74.4 138.2
modulus
(MPa)
Tensile @ 9.3 19.1 23 22.8
Break (Mpa)
Elongation 718 759 579 816
@ Break
Tensile @ 1.5 7.2 4.1 9.2
Yield (Mpa)
Elongation 34 62 19 71
@ Yield
The data in Table 11 show that the
interpolymers of Ex. 3 has better mechanical strength
than the interpolymer Comp. Ex. A, as indicated by a
higher flexural modulus and tensile properties. This
superiority remains after blending with the copolymer
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of Comp. Ex. C as shown by comparing the properties for
Comp. Ex. H with those for Ex. 12.
Examx~le 13-14 and Comp. Ex. I-J
The interpolymers of each of Comp. Ex. A and
Example 3 was blended with 2 wt%, based on polymer
weight, peroxide (Lupersol~ 130, a 2,5 Dimethyl-2,5-di-
(t-butylperoxy) hexyne-3 available from Elf Atochem) to
give, respectively, Comp. Ex. I and Ex. 13 using the
apparatus and procedure of Ex 12, save for reducing the
temperature to 130° C and the rotor speed to 10 rpm.
In the same manner, blends for Ex. 14 and Comp. Ex. J
were prepared from 70 wt~ of the copolymer of Comp. Ex.
C and, respectively, 30 wt~ of the Ex. 3 interpolymer
and the Comp. Ex. A interpolymer together with 2 wto of
the same peroxide, based on combined polymer weight.
The blends were converted into test plaques and the
plaques were exposed to curing conditions using the
procedure of Ex. 5-8. Table 12 summarizes flexural
modulus and tensile/elongation testing results.
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Table 12
Physical Property
Comparison
of Comp.
Ex. I-J and
Ex. 13-
14 (Peroxide
Cured)
Property Comp. Comp. Ex. 13 Ex. 14
Ex. Ex.
(units) I J
Flex modulus 12.7 100.6 74.4 138.2
(MPa)
Tensile @ 9.3 19.1 23 22.8
Break (MPa)
Elongation 718 759 579 816
@
Break
Tensile @ 1.5 7.2 4.1 9.2
Yield (MPa)
Elongation 34 62 19 71
@
Yield
The data in Table 12 show the peroxide cured
interpolymer of Ex. 13 has superior mechanical
properties as compared to that of Comp. Ex. I. The
peroxide cured blend composition (Ex. 14) also has
superior mechanical properties as compared to the
peroxide cured blend composition of Comp. Ex. J. These
superior physical properties are even more surprising
considering that the interpolymer of Comp. Ex. A used
in these blends has a much higher MW (higher Mooney)
than the EAODMs of this invention. These improved
mechanical properties will allow the such EAODMs to be
used in blends with other polymers disclosed herein
where retention of mechanical properties is important.
Examples of such improved blends include more stable
cross-linked polyolefin foams, higher strength cross-
linked wire & cable jackets, and stiffer and more rigid
cross-linked articles.
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Example 15 and Comparative Example R
The interpolymer of Ex. 3 was blended with a
polypropylene (PP) homopolymer (ProfaxT"" PD-
191,available from Himont) in a 70/30 (PP/Ex 3) weight
ratio to make the composition of Ex. 15 using the
apparatus and procedure of Ex. 9 and 10. The extrudate
was compression molded into two sets of test plaques
using the procedure described above for irradiation
tests. The PP homopolymer was compression molded alone
for two sets of Comp. Ex. K test plaques. One set of
test plaques was subjected to EB irradiation at a
dosage of 2 Mrad. IZOD bars were cut from all test
plaques and the bars were tested for notched IZOD
impact strength (ASTM D-256 - Method A) at two
different temperatures (23°C and 0°C). Table 13
summarizes the IZOD test results in kilojoules per
meter (kJ/m).
Table 13
IZOD Impact
Strength
Data for
Polypropylene/EAODM
Blend
in kJ/m
Ex. And Before Before After After
Comp. Ex. IrradiationIrradiationIrradiationIrradiation
(23C) (0C) (23C) (0C)
K 0.080 0.021 0.043 0.043
15 0.821 0.080 0.48 0.085
These results clearly show that the
interpolymers of the present invention improve IZOD
impact strength of polypropylene both before and after
irradiation. Similar results are expected with this
and other EAODMs of this invention when blended with
any of the other polymers disclosed herein.
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Ex. 16-18 and Comp. Ex. L-P
Three interpolymers (Comp. Exs. L, M and N)
each having an ethylene content below 75 wta were
prepared using the method of Comp. Ex. A and Exs. 1-4.
The composition and physical properties for the
interpolymers of Comp. Ex. L-N are described in Tables
14 and 15.
The compositions of Ex. 16, 17 and 18 were
prepared from blends of varying amounts of the
interpolymer of Comp. Ex. N and the interpolymers of
Exs. 1, 3 and 4, respectively. The composition of
Comp. Ex. P was prepared from a blend of the
interpolymers of Comp. Exs. M and N. The amounts of
each polymer were selected such that the average wt o
ethylene of the blend was about 70 wt ~. The blends
were prepared using a Haake mixer. The polymers were
added to the mixer set at a temperature of about 120
°C. The rotor speed was 30 rpm. The polymers were
melted and blended at these conditions for 10 minutes
at which point the temperature of the mixer was reduced
to about 100 °C and the rotor speed was increased to 60
rpm.
The compositions of Ex. 16-18 and Comp. Ex. P were
prepared by adding Carbon Black and Oil to the mixer
and allowing it to mix for about 3 minutes. Sulfur and
other curatives were added to the mixer and allowed to
mix for about 2 minutes. After a total of 15 minutes,
the rotor was stopped and the uncured blends were
removed from the mixer. A composition containing 100
wt~ interpolymer of Comp. Ex. L and designated as Comp.
Ex. O was prepared using the same apparatus and method.
Table 16 summarizes the composition of blend Ex. 16-18
and Comp. Ex. O-P.
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Table
14
Co~mpositioa
Data
Comp. Cz (wt~)C3 (wt~)ENB Cryst.Heat Tg Melting
Ex. of
(wt~) (~) Fusion
(C) Point(C)
(cal/g)
L 69.0 26.0 5.0 11.5 8.0 -38.132.0
M 74.5 23.7 1.8 16.7 11.7 -34.868.9
N 48.3 47.0 4.7 N.A. N.A. -47.5N.A.
N.A.
means
not
applicable
because
the
EAODM
interpolymer
was
amorphous
Table 15
GPC Data
Comp. Ex. I~" - Mn MWD (Mw/Mn)
L 105,000 50,000 2.10
M 97,200 38,700 2.51
N 114,000 50,200 2.27
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Table 16
Composition
Data
Ingredient Comp. Comp. Ex. Ex. 16 Ex. 17 Ex. l8
Ex. O P
Comp. Ex. 100
L
Comp. Ex. 80
M
Comp. Ex. 20 40 50 60
N
Ex. 1 60
Ex. 3 50
Ex. 4 40
Carbon 80 80 80 80 80
Black N-
550
Sunpar 50 50 50 50 50
2280 Oil
Butyl 2 2 2 2 2
Zimate
MBT 1 1 1 1 1
TMTD 0.5 0.5 0.5 0.5 0.5
Zinc Oxide 5 5 5 5 5
Stearic 1 1 1 1 1
Acid
Sulfur 1.5 1.5 1.5 1.5 1.5
Average 69 69 70 68 67
Ethylene
Content
(wt~)
Carbon Black
N-550 is
available
from Engineered
Carbons
Sunpar 2280
is a paraffinic
plasticizer
available
from Sun
Refining
Butyl Zimate
is a Zinc
dibutyl
dithiocarbonate
available
from RT
Vanderbilt
MBT is Mercaptobenzo-thiazole
TMTD is
Tetramethyl
thiuram
disulphide
The cure (vulcanization) properties of Ex. 16-18
were determined on a rotorless cure meter (moving die
rheometer - MDR) according to ASTM D-5289,at a
temperature of 160 °C. The minimum torque (ML) and
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maximum torque (MH), both in Newton-meters (N-M), and
time to reach 95 % of maximum torque (T95) values are
shown in Table 17.
Test specimens for the retraction at low
temperature test (TR) were prepared and tested
according to ASTM D-1329. The test specimens were cut
from vulcanized plaques prepared from each composition.
Each molded plaque was vulcanized at 160 °C for a total
time equal to T95 plus 3 minutes. The temperatures at
which the test specimens retracted 50 % (TR50) are
shown in Table 18.
The results in Tables 17 and 18 show the
interpolymers of this invention can be vulcanized at
approximately the same rate as the Comparative EPDM
(Comp. Ex. O) and comparative EPDM blend (Comp. Ex. P)
with the added benefit of superior TR50 values.
Surprisingly, the temperature of retraction data show
that the addition of a crystalline EAODM polymer
results in improved performance for the vulcanized
blend. A lower temperature of retraction indicates a
more elastic or more rubber like material at low
temperature. The improved low temperature performance
is unexpected since the retraction temperature should
increase as the tendency to crystallize increases.
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Table 17
Vulcanization
Properties
Ex . And Mx ( N-m ML ( N-m T95 ( min
Comp. Ex. ) ) . )
O 2.26 0.17 12.7
p 1.73 0.1 17.9
16 2.35 0.19 11.6
17 2.08 0.12 14.1
18 1.76 0.12 14.6
Table 18
Retraction Data
Ex. And Comp. TR 50 (C)
Ex.
O 3.9
p 8.0
16 -1.8
17 -3.4
18 -12.9
The interpolymers of Exs. 19-21 were prepared
using the method of Exs. 1-4 but at a production rate
ten times (10X) greater than that of Exs. 1-4 (i.e. the
reactor was ten times larger and the flow rates were
ten times greater). Tables 19-22 show the composition
and physical properties for Exs. 19-21.
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Table
19
Composition
Data
Example Cz C2 C, C, ENB CZ/C,
(wt~) (mold)*(wt~) (mold)* (wt~) wt.
Ratio
19 91.8 95.9 4.5 3.1 3.6 20.4
20 93.6 97.7 1.7 1.2 4.7 55.1
21 85.4 91.4 10.6 7.6 4.0 8.1
*Based only on CZ and C3 content .
Table 20
GPC Data
Exam 1e M M MWD (M /M )
19 95,300 49,400 1.93
20 93,200 46,300 2.01
21 91,700 40,700 2.25
Table
21
Density
and
Thermal
Property
Data
ExampleDensityCrystallizationPeak CrystalliHeat Heat Tg*
of of
(g/cc)Onset (C) Meltingnity Fusion Fusion (C)
(~)
Point (joules/(calories
(C) ram) / ram)
19 0.922 - 108 37 108.9 26.1 -15
20 0.924 - 110 38 113.1 27.1 -10
21 ND - 88 23 67.6 16.2 -24
- means
not
measured
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Table
22
Tensile
Strength,
Elongation
and Viscosity
Data
Ex. And Tensile Tensile ElongationElongationMooney
Comp. Strength Strength @ Yield @ Break Viscosity*
Ex. (~) (~)
@Yield @ Break
(MPa)
(MPa)
19 7.9 21.6 7 666 16.9
20 8.9 19.5 8 706 15.2
21 - - - - -
* Measured in accordance with ASTM 171b4b (ML1~4 aL G5=l:)
Ex. 22-30 and Comp. Ex. Q-T
The interpolymers of Ex. 1, 3, 19 and 20 were
blended with various polymers and additives to yield
the compositions of Exs. 22-30. The various polymers
were blended with additives and, in some instances
other polymers, to yield the compositions of Comp. Exs.
Q, R, S and T. The compositions of Exs. 22-30 and
Comp. Exs. Q-T are shown in Tables 23-25. The low
density polyethylene (LDPE), Petrothene NA 940000, was
obtained from Equistar Corporation. This LDPE polymer
has a melt flow rate of 0.25, a polymer density of
0.918 and a crystalline melt point of 104 °C. The
natural rubber, SMR CV-60, was obtained from Akrochem
Corporation and is characterized as a 60 Mooney,
viscosity stabilized Standard Malaysian Rubber (SMR).
The styrene-butadiene rubbers (SBR), Plioflex 1712 and
Plioflex 1502, were obtained from Goodyear Tire and
Rubber Company. Plioflex 1712 is characterized as a 46
Mooney viscosity SBR polymer extended with about 37.5
parts per hundred (phr) aromatic process oil. The
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Plioflex 1502 is characterized as a 50 Mooney viscosity
SBR polymer. The polybutadiene rubber was obtained
from Aldrich Chemical. The additives were carbon
black, oil, zinc oxide, stearic acid, and sulfur
curatives consisting of Butyl Zimate or Methyl Zimate
(a dimethyl dithiocarbonate available from RT
Vanderbilt), MBT, TMTD and sulfur.
The various polymers, interpolymers of Exs.
1, 3, 19 and 20, if any, carbon black, oil, zinc oxide
and stearic acid were added to a Farrel BR Banbury
mixer. The temperature of the Banbury was about 120 °C
to 150 °C. The rotor speed was set to about 80 rpm.
The mix was blended for about 5 minutes. The mix was
removed from the Banbury and sheeted on a Reliable roll
mill. The roll mill was set at a temperature of about
110 °C. The rotor speed was set to about 10 rpm. The
sheet was cut into strips and added to the Farrel BR
Banbury mixer. During this mixing step, the sulfur
curatives were added at a Banbury temperature of about
100 °C to about 110 °C. The rotor speed was set to
about 30 rpm. The. mix was blended for about 2 minutes.
The mix was removed and sheeted on a Reliable roll
mill. The roll mill was set at a temperature of about
100 °C to 110 °C. The rotor speed was set to about 10
rpm. The sheet prepared from each blend was allowed to
cool and subsequently submitted for additional tests.
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Table 23
Composition Data
Ingredient Comp. Comp. Ex. Ex. Ex. Ex.
Ex. Ex. 22 23 24 25
Q R
Natural Rubber SMR-100 100 100 100 100 100
CV-60
LDPE 10
Ex. 1 10
Ex. 3 10
Ex. 19 10
Ex. 20 10
Carbon Black N-550 50
50 50 50 50 50
Sunpar 2280 Oil 6 6 6 6 6 6
Butyl Zimate 2 2 2 2 2 2
MBT 1 1 1 1 1 1
TMTD 0.5 0.5 0.5 0.5 0.5 0.5
Zinc Oxide 5 5 5 5 5 5
Stearic Acid 1 1 1 1 1 1
Sulfur 1.75 1.75 1.75 1.75 1.75 1.75
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Table 24
Composition
Data
Ingredients Comp. Ex. Ex. 26 Ex. 27
S
Natural Rubber75 75 75
SMR-CV-60
Plioflex 1'71225 25 25
Ex. 19 10
Ex. 20 10
Carbon Black 55 55 55
N-
550
Sunpar 2280 6 6 6
Oil
Butyl Zimate 2 2 2
Mercaptobenzo-1 1 1
thiazole (MBT)
Tetramethyl 0.5 0.5 0.5
thiuram
disulphide
(TMTD)
Zinc Oxide 5 5 5
Stearic Acid 1 1 1
Sulfur 1.75 1.75 1.75
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Table 25
Compositiori
Data
Ingredients Comp. Ex. 28 Ex. 29 Ex.30
Ex.
T
Plioflex 1502 85 85 85 85
Polybutadiene 15 15 15 15
Ex. 1 10
Ex. 19 10
Ex. 20 10
Carbon Black 60 60 60 60
N-
550
Sunpar 2280 Oil 6 6 6 6
Methyl Zimate 2 2 2 2
Mercaptobenzo- 1 1 1 1
thiazole (MBT)
Tetramethyl 0.5 0.5 0.5 0.5
thiuram
disulphide
(TMTD)
Zinc Oxide 5 5 5 5
Stearic Acid 1 1 1 1
Sulfur 1.75 1.75 1.75 1.75
The vulcanization properties of the interpolymers
of Ex. 22-30 and Comp. Ex. Q-T were determined on a
rotorless cure meter (moving die rheometer - MDR)
according to ASTM D-5289. These vulcanization
properties were determined at a temperature of 160 °C.
The minimum torque (ML), maximum torque (MH) and time to
reach 90 ~ of maximum'torque (T9o) values for each blend
are shown in Table 26.
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Table 26
Vulcanization
Properties
Ex. And Comp. MH (N-m) ML (N-m) T9a (min. )
Ex.
Q 2.02 0.26 1.3
R 1.77 0.04 1.6
22 1.82 0.27 1.6
23 1.75 0.25 1.7
24 1.73 0.27 1.8
25 1.68 0.17 1.8
S 2.51 0.19 2.0
26 2.24 0.35 2.2
27 2.12 0.17 2.0
T 2.69 0.18 4.6
28 2.4 0.21 5.7
29 2.36 0.23 5.8
30 2.19 0.24 6.4
Test specimens for abrasion resistance were
prepared and tested according to ISO 4649-1985(E). The
test specimens were cut from vulcanized plaques
prepared from each blend. Each molded plaque was
vulcanized at 160 °C for a total time equal to T9o plus
5 minutes. The plaque size was 7.6 cm by 7.6 cm at a
thickness of about 6.5 mm. The abrasion data are shown
in Table 27 and are reported as volume loss relative to
a standard. A lower value is considered to be
indicative of higher resistance to abrasive wear.
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WO 00/69930 PCT/US00/13159
Table 27
Abrasion Resistance
Data
Ex. And Comp. Ex. Abrasion
Resistance
(Volume Loss)
Q 125.8
R 122.3
22 115.4
23 110.5
24 103.2
25 98.2
S 125.7
26 111.6
27 112.9
T 106.2
28 96.4
29 91.6
30 88.8
Examples 22-30 demonstrate that the addition
of crystalline EAODM of this invention to different
rubber formulations (such as natural rubber, styrene-
butadiene rubber and polybutadiene rubber) imparts
improved abrasion resistance and performance when
compared to those blends not containing these polymers
and does so without affecting the vulcanization
performance as shown in Table 26. Applications where
abrasion resistance is needed and improved abasion
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resistance would be advantageous include pneumatic
tires, footwear, and conveyor belts.
Ex 31-44 aad Comp. Ex. U
Examples 31-44 demonstrate the utility of
interpolymers of this invention in foam applications.
Data have been obtained on different crosslinked
formulations. Typical methods for crosslinking foam
formulations containing EAODM polymers include
peroxide, sulfur, vinylalkoxysilane, hydrosilation,
phenolic, electron beam, gamma and ultraviolet
radiation. The foam data demonstrate the utility and
enhanced foaming capability of crystalline EAODM
polymers especially when blended with other ethylene
interpolymers including low density polyethylene
(LDPE), ethylene-vinyl acetate (EVA), ethylene
copolymers such as ethylene-octene and ethylene-butene,
ethylene-styrene, LLDPE and HDPE polymers. These data
also demonstrate the enhanced foaming capability of
crystalline EAODM polymers when blended with
polypropylene polymers including homopolymers and
copolymers. Other types of foaming agents (e. g.
carbonates) could be used giving rise to either closed
or open cell foams.
The low density polyethylene (LDPE) in Ex. 40 was
Petrothene NA 940000, obtained from Equistar
Corporation. The typical properties for this LDPE
polymer are a melt flow rate of 0.25, a polymer density
of 0.918 and a crystalline melt point of 104 °C. The
ethylene-vinyl acetate copolymer in Ex. 39 was Elvax
460, obtained from E. I. du Pont de Nemours and
Company. The typical properties for this EVA polymer
are a density of 0.941 g/cc, a melt flow rate of 2.5
dg/min, a GPC molecular weight (Mw) of 80,000 and
molecular weight distribution of 5.0 and a vinyl
acetate content of 18 wt
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The interpolymers of Ex. 19, 20, and 21 were
blended as shown in Table 28 on a Farrel BR Banbury
mixer. For Examples 31-33, foaming agent and
activators were added to the Farrel BR Banbury mixer at
a melt temperature of about 130 °C. For Examples 34
and 35, and Comp. Ex. U, polypropylene and foaming
agent were added to the Farrel BR Banbury mixer at a
melt temperature of about 175 °C. After about 5
minutes of mixing, each formulation was removed from
the Banbury and sheeted on a Reliable roll mill. From
these sheets, two compression molded test plaques were
prepared. The plaque size was 12.7 cm by 12.7 cm at a
thickness of about 0.3175 cm. One set of test plaques
were electron beam irradiated at 2 Mrad while the other
set of test plaques were electron beam irradiated at 5
Mrad. After irradiation, the plaques were tested for
gel content using the Standard Test Method for
Determination of Gel Content as described in ASTM D-
2765 test method. The gel content for each plaque
after irradiation is shown in Table 29.
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Table 28
Composition
Data
Ingredient Comp. Ex. 31 Ex. 32 Ex. 33 Ex. 34 Ex. 35
Ex. U
Ex. 19 100
Ex. 20 100 30
Ex. 21 100 30
Polypropyl 100 70 70
ene
Celogen AZ 6 6 6 6 6 6
130
Zinc Oxide 0 1 1 1 0 0
Stearic 0 0.5 0.5 0.5 0 0
Acid
All amounts
are Parts
per Hundred
(pph)
Polypropylene
was Profax
PD-191 from
Himont
Celogen AZ130
is an azodicarbonamide
available
from Uniroyal
Chemical
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Table 29
Gel Content Data
Ex. And Comp. Ex. o Gel Content at o Gel Content at 5
2 Mrad
Mrad
Ex. 31 72 91
Ex. 32 81 91
Ex. 33 38 75
Ex. 34 15 ' 26
Ex. 35 19 29
Comp. Ex. U 0.3 0.5
Bun foams were prepared from Examples 31-33,
irradiated at both 2 Mrad and 5 Mrad. 5.1 cm by 5.1 cm
test samples were cut from the compression molded,
irradiated test plaques and placed in a mold cavity of
the same size and thickness. The cavity mold was placed
into a heated, hydraulic molding press set at a
temperature of 165 °C with a molding pressure of 20,000
lbs. (9100 Kg). The cavity mold was left in the press
for about 10 minutes and the pressure then quickly
released. The sample was removed from the press and
allowed to freely expand. After expansion, the foam
density of each sample was determined by weighing a
known volume. The foam density data are shown in Table
30.
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WO 00/69930 PCT/US00/13159
Table 30
Foam Density
Data
Examples Foam Density Foam Density
(g/cc) (g/cc)
2 Mrad 5 Mrad
Ex. 31 0.16 0.47
Ex. 32 0.28 0.56
Ex. 33 0.55 0.19
Table 30 shows the interpolymer blends of Ex. 31-
33 can be foamed after irradiation crosslinking and
there is an optimum irradiation dosage depending on
ethylene content and amount of gel content. For
polymers of this invention, a low irradiation dosage is
preferred in order to obtain optimum foam densities.
Hot air oven, free rise foams were prepared from
Ex. 31-35 and Comp. Ex. U irradiated at 2 Mrad. Test
samples, 2.54 cm by 2.54 cm in size, were cut from the
compression molded, irradiated test plaques. For Ex.
31-33, the test samples were placed in a hot air oven
at a temperature of 180 °C for about 10 minutes. For
Ex. 34-35 and Comp. Ex. U, the test samples were placed
in a hot air oven at a temperature of 220 °C for about
10 minutes. The foamed test samples were removed from
the oven and the foam density of each sample was
determined by weighing a known volume. The foam
density data are shown in Table 31.
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Table 31
Foam Deasa.ty Data
Ex. And Foam
Comp. Density
Ex. (g/cc)
for
2
Mrad
Dosage
Ex. 31 0.14
Ex. 32 0.21
Ex. 33 0.39
Ex. 34 0.08
Ex. 35 0.08
Comp. Ex. U 0.37
Table 31 shows hot air oven free rise foams can be
prepared from interpolymers and interpolymer blends of
this invention. The foam density data show blends
containing interpolymers of this invention exhibit
lower foam density. The foam density data for the
polypropylene blends show the improved foaming of the
blend samples containing the inventive interpolymers
(Ex. 34 and 35) as compared to the polypropylene blend
sample (Comp. Ex. U). It would be expected that
polymers of this invention could be blended with other
ethylene polymers such as LDPE, EVA, LLDPE, EAODM,
ethylene alpha-olefin copolymers and terpolymers ,
ethylene-styrene and HDPE and subsequently irradiated
to give foamed articles having low foam densities.
The formulations shown in Table 32 were prepared
using the combination of a Farrel BR Banbury mixer and
a Haake Rheocord 9000 mixer. All of the formulation
components except the peroxide were premixed using a
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Farrel BR Banbury mixer at a melt temperature of about
130 °C. After about 5 minutes of mixing, each blend
was removed from the Banbury and sheeted on a Reliable
roll mill. These sheets were then diced into irregular
cubes of about 2 cm in size. For the peroxide
addition, each premixed sample (as cubes) was added to
a Haake Rheocord mixed and allowed to melt before the
addition of the Di-Cup 40 KE a dicumyl peroxide. The
conditions for blending on the Haake mixer were a melt
temperature of 130 °C and a rotor speed of about 5 rpm.
After about 5 minutes of melt blending, each sample was
removed from the Haake and allowed to cool.
Table 32
Composition Data
Ingredient Ex. 36 Ex. 37 Ex. 38 Ex. 39 Ex. 40
Ex. 19 100
Ex. 20 100 40
Ex. 21 100 40
EVA 60
LDPE 60
Celogen AZ 130 6 6 6 6 6
Zinc Oxide 1 1 1 1 1
Stearic Acid 0.5 0.5 0.5 0.5 0.5
Di-Cup 40 KE 0.806 0.806 0.806 0.806 0.806
All amounts are
Parts per Hundred
(pph)
Each formulation sample was compression molded at
a pre-molding temperature of 130 °C using a heated
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hydraulic press. The mold cavity used for this was
about 10.2 cm by 10.2 cm with a thickness of 1.3 cm.
After molding at 130 °C, the mold cavity containing the
sample was then crosslinked at a temperature of 160 °C
using a total pressure of about 20,000 lbs. The cavity
mold containing the sample was left in the press for a
time of about 20 minutes. After this time, the
pressure was quickly released. The sample was removed
from the press and allowed to freely expand. For each
foamed sample, the % gel content and foam density
values were determined as previously described. These
data are shown in Table 33.
Table 33
Gal Content
and Foam Density
Data
Example Gel Content Foam Density
(%) (g/cc)
Ex. 36 82 0.15
Ex. 37 82 0.19
Ex. 38 70 0.10
Ex. 39 71 0.09
Ex. 40 70 0.10
The data in Table 33 demonstrates foams can be
prepared from examples of this invention using peroxide
crosslinking. Optimum amounts of peroxide can be
adjusted depending on the interpolymer added and
desired foam density.
The formulations shown in Table 34 were prepared
using the combination of a Farrel BR Banbury mixer and
a Haake Rheocord 9000 mixer. All of the formulation
components except the sulfur curatives were premixed
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using a Farrel BR Banbury mixer at a melt temperature
of about 130 °C. After about 5 minutes of mixing, each
formulation was removed from the Banbury and sheeted on
a Reliable roll mill. These sheets were then diced
into irregular cubes of about 2 cm in size. For the
addition of the sulfur curatives, each premixed sample
(as cubes) was added to a Haake Rheocord mixed and
allowed to melt before the addition of the sulfur
curatives. The conditions for blending on the Haake
mixer were a melt temperature of 130 °C and a rotor
speed of about 5 rpm. After about 5 minutes of melt
blending, each sample was removed from the Haake and
allowed to cool.
Table 34
Composition
Data
Ingredients Ex. 41 Ex. 42 Ex. 43 Ex. 44
Ex. 20 100 40
Ex. 21 100 40
EVA 60
LDPE 60
Celogen AZ 6 6 6 6
130
Zinc oxide 5 5 5 5
Stearic Acid 1 1 1 1
Butyl Zimate 0.33 0.33 0.33 0.33
MBT 0.17 0.17 0.17 0.17
TMTD 0.88 0.88 0.88 0.88
Sulfur 0.25 0.25 0.25 0.25
All amounts
are Parts
per Hundred
(pph)
Each blend sample was compression molded into a
plaque at a pre-molding temperature of 130 °C using a
heated hydraulic press. The plaque size was about 12.7
cm by 12.7 cm at a thickness of about 0.3175 mm. From
each plaque, smaller test samples were cut. These test
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samples were 2.54 cm by 2.54 cm in size with a
thickness of 0.3175 cm. These test samples were placed
in a hot air oven at a temperature of 200 °C for about
minutes. The foamed test samples were removed from
5 the oven and submitted for testing. For each foamed
sample, the % gel content and foam density values were
determined as previously described. Results are shown
in Table 35.
Table 35
Gel Content
and Foam
Density Data
Example Gel Content Foam Density
(g/cc)
Ex. 41 64 0.22
Ex. 42 75 0.24
Ex. 43 65 0.3
Ex. 44 55 0.24
Table 35 demonstrates that sulfur crosslinking of
polymers of this invention can produce acceptable
foamed articles. Optimum amounts of sulfur curatives
can be adjusted depending on the interpolymer and
desired foam density. Interpolymers of this invention
can be blended with other ethylene polymers such as
LDPE and EVA (other ethylene polymers would include
LLDPE, ethylene alpha-olefin copolymers, ethylene-
styrene and HDPE), other sulfur curable natural or
synthetic rubbers, and subsequently sulfur crosslinked
to give foamed articles having low foam densities.
Ex. 45 - 47
An ethylene-butene- ethylidene norbornene
terpolymer of this invention was prepared in a manner
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similar to Ex. 1-4. The composition and properties for
the EAODM polymer are shown in Table 36.
Table
36
Compositioa,
Thermal
Property
egad
GPC
Data
C= C, ENB CrystHeat Tg MeltingN~" M MWD
of
(wt~)(wt~)(wt~)(~) Fusion (C) Point
(cal/g) (C)
Ex. 88.5 7.5 4.0 35 24.7 -20 103 94,40047,0002.01
45
The interpolymer of Ex. 45 was blended~with sulfur
and phenolic curatives/accelerators in a Haake Rheocord
9000 mixer to make the formulations of Ex. 46 and 47.
The formulation of Ex. 46 was prepared using the
interpolymer of Ex. 45, sulfur curative and
accelerators. The formulation of Ex.47 was prepared
using the interpolymer of Ex. 45, phenolic curatives
and accelerators. The conditions for blending on the
Haake mixer were a melt temperature of 130 °C and a
rotor speed of about 5 rpm. The polymer was added to
the mixer and allowed to melt. After about 3 minutes,
the sulfur or phenolic curatives and accelerators were
added. After about 2 minutes of melt blending, the
sample was removed from the mixer and allowed to cool.
The sulfur and phenolic formulations are shown in Table
37.
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Table 37
Composition Data
Ingredient Ex. 46 Ex. 47
Ex. 45 100 100
Zinc oxide 5 2.1
Stearic Acid 1
Butyl Zimate 2
MBT 1
TMTD 0.5
Sul fur 1. 5
Dimethylol Phenolic 10.1
Curative SP-1045
Tin Chloride Dihydrate 2.8
Mg0 2.0
The blends were tested for vulcanization
properties using Standard Test Method for Rubber
Property Vulcanization Using Rotorless Meter as
described in ASTM D-5289 (moving die rheometer - MDR).
The blend of Ex. 46 with sulfur curative and
accelerators was tested at a temperature of 160 °C.
The blend of Ex. 47 with phenolic curatives and
accelerators was tested at a temperature of 200 °C.
The minimum torque (ML), maximum torque (MH) and time to
reach 95 % of maximum torque (T95) values are shown in
Table 38.
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Table 38
Vulcanization
Properties
Example MH (N-m) ML (N-m) T95 (min. )
Ex. 46 1.55 0.12 13.64
Ex. 47 0.66 0.03 16.00
The data in Table 38 show the EAODM of Ex. 45 can
be vulcanized with sulfur and phenolic
curative/accelerators. Other types of crosslinking
could be used including peroxide, irradiation (E-beam,
gamma, UV), silane, and hydrosilation. Possible end-
use applications for these polymers would be in
polyolefin foams (footwear, automotive interior),
vulcanized rubber blends (tires, weatherstripping),
crosslinked polyolefin blends (films, fiber, tubing),
and thermoplastic vulcanizates (TPV's)
Ex. 48
The interpolymer of Ex. 20 was vulcanized using
hydrosilation curative and platinum catalyst. First,
the interpolymer of Ex. 20 (100 pph) was added to a
Haake Rheocord 9000 mixer and allowed to melt at a melt
temperature of 130 °C. After about 3 minutes, the
hydrosilation curative (3 pph silicon hydride Type 1107
Fluid from Dow Corning) and platinum catalyst (20 ppm
of SIP 6831.0 from Gelest, Inc.) were added and
allowed to mix at a rotor speed of about 5 rpm. After
about 5 minutes of melt blending, sample was removed
from the mixer and allowed to cool to give the
vulcanized interpolymer of Ex. 48 and was tested for
vulcanization properties using Standard Test Method for
Rubber Property Vulcanization Using Rotorless Meter as
described in ASTM D-5289 (moving die rheometer - MDR).
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The composition of polymer blended with hydrosilation
curative and catalyst was tested at a temperature of
190 °C. The minimum torque (ML) was 0.04 N-m, the
maximum torque (MH) was 0.1 N-m., and time to reach 95
0 of maximum torque (T95) was 16.50 min. These results
that interpolymers of this invention can be
successfully cured using hydrosilylation vulcanization.
Ex. 49 and Comp. Ex. V
The following comparative example and example
compare the biaxial orientation of linear low density
polyethylene (LLDPE) to a blend of LLDPE with
interpolymers of this invention. The subsequent
utility of both in shrink film applications also is
compared.
The interpolymer of Ex. 19 was blended with the
LLDPE of Comp. Ex. C in a 10/90 weight ratio,
respectively, to prepare the blend of Ex. 49. Blending
was done in a 64mm 36/1 L/D (Length/Diameter) single
screw extruder. The following conditions were used on
the 64 mm extruder: Barrel Temperature Zones were Zone
1 = 82 °C, Zone 2 = 127 °C, Zones 3-5 = 190 °C with
Screen Changer Temperature = 204°C and Adapter and Die
Temperature = 218°C. The extruder speed was 31 rpm.
Strands were extruded, water quenched, then chopped
into pellets. These pelletized compounds were extruded
into sheeting using a 50 mm 24/1 L/D single screw
extruder. Extruder barrel temperature zones were Zone
1 = 216 °C, Zone 2 = 238 °C, Zone 3 - 249 °C, Adapter and
Die Temperature = 218°C. The extruder speed was 34 rpm
at 19.5 amps. The Casting Roll Temperature was 39°C,
the die width was 30.5 cm., sheet thickness was
0.64mm, and sheet width was 52.4 cm
Sheets of the blends of Ex. 49 and the LLDPE
of Comp. Ex. C were rolled onto cardboard cores. These
sheets were then electron beam irradiated at 4.0 Mrad
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dosage at a line speed of 6.1 m/min to produce
irradiated sheets of the blend of Ex. 49 and the LLDPE
of Comp. Ex. V. The irradiated sheeting was then
oriented in the machine direction (MDO) to a 5:1 draw
ratio using a series of heated rollers with
differential roll speed. The conditions for the MDO
draw were a preheat temperature of 98.3 °C , slow draw
rolls running at 2.4m/min. and 109°C, fast draw rolls
running at 12.3 m/min. and 109°C, annealing roll at
12.3 m/min. and 36°C, chill roll at 12.3 m/min and 19.4
°C. Sheet thickness was 0.13 mm.
The MDO drawn sheet was oriented in the transverse
direction using a tender frame device heated via
convection oven and equipped with a horizontal chain
and flexible grip system for transverse direction
orientation (TDO). Conditions used for TDO stretching
for Comp. Ex. V was a preheat temperature of 113°C, a
stretch temperature of 113°C, and an annealing
temperature of 96°C. Conditions used for TDO stretching
for the blend of Ex. 49 was a preheat temperature of
116°C, a stretch temperature of 116°C, and an annealing
temperature of 99°C. The films were cooled via
circulating ambient air prior to windup. Film
thickness was 0.025 mm.
The films were tested for crosslinked gel in
accordance with ASTM D-2765, Method A. The film of Ex.
49 had and average gel content of 25.41. The film of
Comp. Ex. V had an average gel content of 0.68°x.
These results show the large increase in crosslinking
ability of blends containing polymers of this
invention.
The tensile strength at break of the film of Ex.
49 and Comp. Ex. V was measured in the MDO and TDO,
according to ASTM D-882. The results are shown in
Table 39. The film of Ex. 49 exhibited higher tensile
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strength at break in both the MDO and TDO than Comp.
Ex. V.
Table 39
Tensile Strength
Data
Film MDO MDO TDO TDO
Direction Comp. Ex. Ex. 49 Comp. Ex. Ex. 49
V V
Tensile 65.3 72.4 94.3 117.0
Strength
@break
(Mpa)
Shrink tension was measured in the MDO at 125°C,
according to ASTM D2838, Method A. The film of Ex. 49
had a MDO shrink tension of 1.73 Mpa and Comp. Ex. V
had a MDO shrink tension of 1.13 Mpa. Thus, electron
beam irradiated biaxially oriented films containing the
inventive high crystalline interpolymers exhibit higher
levels of crosslinking, tensile strength at break, and
shrink tension, than films lacking the inventive
interpolymers. These interpolymers of the invention
can be used as blend components or alone to exhibit
high gel response to electron beam irradiation for
biaxially oriented shrink films.
Ex. 50-51 and Comp. Ex. w-X
The interpolymer of Ex. 20 was blended with a
LDPE, LD 400.09 (available from Exxon Chemical
Company), having a melt index of 2.8 dg/min and a
density of 0.917 g/cc and a high density polyethylene
(HDPE), Sclair 59A (available from Nova Chemicals),
having a melt index of 0.7 dg/min, and a density of
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0.962 g/cc. The blend with the LDPE yielded the
composition designated Ex. 50 and the one with the HDPE
yielded the composition designated Ex. 51. 100 wt~ of
the LDPE was designated Comp. Ex. W. 100 wt~ of the
HDPE was designated Comp. Ex. X. The blend
compositions were prepared on a Werner Pfleiderer ZSK-
30 co-rotating twin screw extruder with a medium-high
shear screw configurations. The blend compositions are
shown in Table 40 and blend conditions are shown in
Table 41.
Table 40
Composition
Data
Ingredients Comp. Comp. Ex. 50 Ex. 51
Ex. X Ex. W
Ex. 20 30 30
HDPE 100 70
LDPE 100 70
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Table 41
Extruder Conditions
Extruder Comp. Ex. Comp. Ex. Ex. 50 Ex. 51
Conditions X W
Zone 1 145 110 145 110
Temp.
Zone 2 209 180 215 185
Temp.
Zone 3 225 200 230 200
Temp.
Zone 4 240 220 245 235
Temp.
Zone 5 230 220 235 240
Temp.
Die Temp. 210 200 205 210
Speed 250 270 250 240
(rpm)
Temperatures
are in C
The pelletized blends in Table 40, after being
mixed and pelletized according to Table 41, were
extrusion processed into sheeting using a 50 mm 24/1
L/D Killion single screw extruder fitted with a 15 cm
wide sheet die. Conditions used to extrude these
sheets is shown in Table 42.
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Table 42
Extruder Conditions
Extruder Comp. Ex. Comp. Ex. Ex. 50 Ex. 51
Conditions X W
Zone 1 205 85 205 90
Temp.
Zone 2 205 188 205 165
Temp.
Zone 3 205 188 205 165
Temp.
Die Temp. 82 175 82 160
Speed 28 31 32 28
(rpm)
Temperatures
are in C
One millimeter thick sheeting of Comp. Ex. W-X and
the blends of Ex. 50-51 was produced and cooled on a
Killion 25 cm wide three roll stack. The sheets were
then irradiated via electron beam to 2 Mrad dosage.
The irradiated sheets were tested for gel response as
measured according to ASTM D2765, Method A. Results
are shown in Table 43. The sheeting samples containing
polymers of this invention exhibit much higher gel
levels than Comp. Ex. W and X which contain no polymers
of this invention.
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Table 43
Gel Content
Data
Comp. Ex. Comp. Ex. Ex. 50 Ex. 51
X W
Average 2.64 9.37 51.2 59.93
Gel (~)
The irradiated sheeting was cut into 20 cm x 10 cm
strips. These strips were drawn in the machine
direction in a United tensile testing machine equipped
with an environmental chamber. The tensile testing
machine was fitted with a multihead grip capable of
gripping across the 10 cm width. Prior to drawing, the
sample was allowed to preheat in the environmental
chamber at the preset temperature for ten minutes. The
preset environmental chamber temperature for each blend
is shown in Table 44. Different chamber temperatures
were used depending upon the type of polyethylene used.
The chamber temperature was set at or near the melting
point of the polyethylene. After the ten minute
preheat time, the sheeting samples were drawn to a 2:1
draw ratio in the machine direction using a crosshead
speed of 50 mm/min. Immediately after reaching a 2:1
draw ratio, the crosshead was stopped, the
environmental chamber was opened, and the samples,
still under tension, were cooled with air from pressure
lines. The stretched sheeting samples were tested for
shrink tension at 150 °C according to ASTM D2838,
Method A. Table 45 shows the shrink tension results.
The shrink tension was four to five times higher for
examples of this invention (Ex. 50-51) than for Comp.
Ex. W-X which contained no polymers of this invention.
High crystalline EAODM can be used in blends with
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either LDPE, HDPE, or other polyethylenes to yield
shrink articles such as shrink sleeves, shrink tubing,
shrink lining, etc. with higher cross-link and shrink
tension at equal orientation and electron beam dose
levels.
Table 44
Preset Environmental
Chamber Temperatures
Comp. Ex. Comp. Ex. Ex. 50 Ex. 51
x w
134 110 134 110
Temperatur
(C)
Table 45
Shrink Tension
Data
Ex. and Comp. Orientation Temperature Shrink
Ex. (C) Tension (MPa)
Comp. Ex. X Machine 150 0.09
Comp. Ex. W Machine 150 0.08
Ex. 50 Machine 150 0.50
Ex. 51 Machine 150 0.36
Ex. 52
The interpolymer of Ex. 2 (85pph) was mixed on a
two roll mill with 1 part 4-chlorobenzophenone and 15
parts hexanediol diacrylate to provide the formulation
of Ex. 52. Slabs of 2 mm thickness were then pressed
from the formulation. The slab was then exposed to an
80 W/cm 5 cm long W lamp. The lamp was placed 10 cm
from the slab and the exposure time was 4 minutes.
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After exposure, the crosslinked interpolymer of Ex.52
had a compression set (25~ deflection) at 125°C for 70
hrs. of 45~. These results clearly indicate that the
highly crystalline EAODM based compounds of this
invention can be crosslinked using ultraviolet light.
Ex. 53-56 aad Comp. Ex. Y
The interpolymers of Ex. 2, 19, and 20 were
grafted with malefic ahydride. 240 grams of each
interpolymer were added to a Haake Mixer at a
temperature of 200 °C. The rotor speed was set to 50
rpm. The polymer was allowed to melt for about 1
minute, followed by addition of 7.2 grams of malefic
anhydride. This operation was conducted with the metal
ram in the closed position. After about 5 minutes, the
rotor was stopped and grafted interpolymer of Ex. 53-55
was removed from the Haake mixer. The amount of
grafted malefic anhydride on each polymer was determined
using infrared absorbance with the interpolymers of Ex.
53 having 0.35 wt~, Ex. 54 having 0.40 wt~, and Ex. 55
having 0.50 wt % malefic anhydride.
The interpolymers of Ex. 53 and Ex. 2 were blended
with a polyamide polymer (Capron 8200 obtained from
Allied Signal). The polyamide polymer was pre-dried at
70°C for 24 hours before using. The interpolymer of
Ex. 53 and Ex. 2 were granulated in a K-Tron granulator
to an average diameter of about 0.1875 inches before
extruder blending. The blend was prepared on a 18
millimeter Haake co-rotating twin screw extruder having
a 30:1 L/D ratio. The extruder speed was set at 50
rpm. The zone temperatures were profiled from 240 °C
to 260 °C from the feed throat to the die. The melt
temperature at the die was about 260 °C. The extruder
was equipped with a two hole die, water bath, air knife
and strand chopper. The molten polymer strands were
cooled in the water bath and pelletized to an average
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pellet size of about 0.125 inches to give Comp. Ex. Y
(80 wt% Capron 8200 and 20 wt% interpolymer of Ex. 2)
and the interpolymer blend of Ex. 56 (80 wt% Capron
8200 and 20 wt% grafted interpolymer of Ex. 53).
The grafted interpolymer of Ex. 56 and Comp. Ex. Y
were injection molded on an Arburg Injection Molding
machine using a standard ASTM mold. IZOD test bars
were molded at a standard thickness of 0.125 inches.
The molding conditions were 260 °C melt temperature
with an 80 °C mold temperature. The injection molded
IZOD test bars were notched and tested for impact
properties at room temperature according to ASTM
conditions. The room temperature IZOD impact
properties are shown in Table 46. The malefic anhydride
grafted interpolymers of this invention can impact
modify a polyamide polymer (Nylon 6). Tn~hen the
interpolymers of this invention are not grafted with
malefic anhydride, compatibility is poor and is
reflected in the poor IZOD impact performance.
Table 46
Impact Strength Data
Ex. And Comp. Ex Room Temp. IZOD Impact
Strength
(Joules/cm)
Capron 8200 0.67
Comp. Ex. Y 0.58
Ex. 56 5.50
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Ex. 58-61 and Comp. Ex. Z-AA
These examples compare the adhesion of low density
polyethylene LDPE, HDPE and EAODM polymers of this
invention to a styrene-butadiene rubber (SBR)
substrate. The styrene-butadiene rubber (SBR),
Plioflex 1502, was obtained from Goodyear Tire and
Rubber Company. The Plioflex 1502 sample is
characterized as a 50 Mooney viscosity styrene-
butadiene rubber. The LDPE, Petrothene NA 940000, was
obtained from Equistar Corporation. The typical
properties for this LDPE polymer are a melt flow rate
of 0.25, a polymer density of 0.918 and a crystalline
melt point of 104°C. The HDPE, Petrothene LR 73200,
was obtained from Equistar Corporation. The typical
properties for this HDPE polymer are a melt flow of
0.30, a polymer density of 0.955 and a crystalline
melting point of 125 °C.
Compression molded plaques were prepared from each
of the styrene-butadiene rubber, LDPE, HDPE and the
interpolymers of Ex. 1, 3, 19, and 20. The plaques
were 15.2 cm by 15.2cm having a thickness of about 3.17
mm. Adhesion test specimens, 2.54 cm (width) by 5.58cm
(length) were cut from the plaques. The adhesion of
the LDPE, HDPE, and the interpolymers of Ex. 1, 3, 19,
and 20 to the SBR was evaluated by placing three test
specimens of each polymer type in contact with the
styrene-butadiene rubber. The polymer to styrene-
butadiene rubber laminates were placed in an oven set
at 150 °C. After one hour, the polymer to styrene-
butadiene rubber laminates were removed from the oven,
allowed to cool and manually checked for adhesion. The
adhesion test was conducted using a manual 90 degree
pull. The level of adhesion was determined by evidence
of cohesive failure between the test polymers and the
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styrene-butadiene rubber substrate. The LDPE (Comp.
Ex. Z) and HDPE (Comp. Ex. AA) laminates showed no
adhesion whereas laminates of Ex. 58, 59, 60, and 61
(prepared from interpolymers of Ex. 1, 3, 19, and 20
respectively) exhibited adhesion. Furthermore, better
adhesion was obtained as ethylene content of the
crystalline EAODM polymer was increased. Adhesion of
the crystalline EAODM polymers would be important in a
number of different elastomer applications including
tires e.g., as the low permeability inner liner),
automotive weatherstrip (e.g., in the low COF
(Coefficient of Friction) and wear resistant layer),
vulcanized rubber composites (e. g., in windshield wiper
blades and engine motor mounts) and other laminated or
coextruded articles.
Ex. 62 aad Comn. Ex. AB
15 wto of the interpolymer of Ex. 1 (15 wt~) was
blended with 85 wt~ Nordel IP 4770 EPDM which is
available from DuPont Dow Elastomers) on a Farral 1D
Banbury to give blend Ex. 62. The typical properties
for Nordel IP 4770 are an ethylene content of 70 wt~
and a Mooney Viscosity ML (1+4) @ 125 °C of 70. 100
wto Nordel IP 4770 was used as a control and
designated Comp. Ex. AB. The blend of Ex. 62 and the
polymer of Comp. Ex. AB each were extruded on a Davis-
Standard extruder using a standard rubber screw (L/D is
20:1) at a screw speed of 17 RPM using a
weatherstripping die. Barrel temperatures were 65.5°C
in zone 1, 71°C in zone 2, 82°C in zone 3 and a die
temperature of 37.8°C. Extruder speed was 81.3 mm/sec
Post die measurements were taken 15 cm from the die.
End of line measurements were taken about 6 m from the
die after the extruded material went through a room
temperature air blowing chamber. The interpolymer
blend of Ex. 62 had a post die height of 4.76 mm and an
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end of line height of 4.76 mm whereas Comp. Ex. AB had
a post die height of 5.56 mm and an end of line height
of 3 . 97 mm.
Table 47
Tensile Green Strength
Data
Ex. and Comp. Ex. Tensile Green Tensile Green
Strength @50 C Strength @70 C
(Mpa) (Mpa)
Ex. 62 0.24 0.115
Comp. Ex. AB 0.16 0.098
The addition of the interpolymer of Ex. 1 to Comp.
Ex. AB improves both the tensile green strength (Table
47) and collapse resistance of the material, both of
which are desirable improvement for profile extrusion
applications such as hose and weatherstripping because
the profiles need to maintain their die shape until
the materials can be cured.
Ex. 63-72 and Comp. Ex. AC-AD
The blends in Table 48 were prepared using a
"right side up mix procedure" (polymers and resins
charged before fillers and oils) in a Reliable (B size,
1.7 L chamber volume), tangential-rotor internal mixer
operating at 70 rpm. Ingredient weights were adjusted
to provide 70~ fill of the mixer volume. Amorphous
EPDM interpolymers, Nordel IP 4570 and Nordel IP 4770
were used. Typical properties of Nordel IP 4570 are an
ethylene content of 50 wt~ and a Mooney ~Jiscosity ML
(1+4) at 125°C of 70. The amorphous interpolymers and
crystalline interpolymers of the invention were charged
to the mixer first, followed by the fillers (carbon
black, calcium carbonate) and oil. The ram was lowered
and the blends mixed to 88°C. At 88°C the ram was
raised and the throat and ram were swept of loose
fillers. The ram was lowered and the compounds
77
CA 02372056 2001-10-29
WO 00/69930 PCT/IJS00/13159
discharged at 127°C and sheeted off on a 40.6 cm mill.
The compounds were conditioned at 23°C for 24 hours
before addition of curatives. The compounds were
charged to the mixer and mixed to 66°C. The ram was
raised and swept, then the curatives added. The ram
was lowered and the compounds were taken to 88°C and
the throat and ram were swept. The ram was lowered and
the compounds discharged at 104°C and sheeted off on a
40.6 cm mill.
Table 48
Composition
Data
IngredientCompComp Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex.
Ex. Ex. 63 64 65 66 67 68 69 70 71 72
AC AD
Nordel 100 0 95 90 85 80 75 95 90 85 80 75
IP
4570
Nordel 0 100 0 0 0 0 0 0 0 0 0 0
IP
4770
Ex. 1 0 0 5 10 15 20 25 0 0 0 0 0
Ex. 19 0 0 0 0 0 0 0 5 10 15 20 25
Carbon 130 130 130 130 130 130 130 130 130 130 130 130
Black
N-550
CaCO, 50 50 50 50 50 50 50 50 50 50 50 50
Sunpar 70 70 70 70 70 70 70 70 70 70 70 70
2280
Butyl Zimate1 1 1 1 1 1 1 1 1 1 1 1
Mercaptobenz1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5
o-thiazole
(MBT)
Tetrone 0.750.75 0.750.750.75 0.750.750.75 0.750.750.75 0.75
A
TMTD 0.750.75 0.750.750.75 0.750.750.75 0.750.750.75 0.75
Ca0 8 8 8 8 8 8 8 8 8 8 8 8
Zn0 5 5 5 5 5 5 5 5 5 5 5 5
Stearic 1 1 1 1 1 1 1 1 1 1 1 1
Acid
Sulfur 1 1 1 1 1 1 1 1 1 1 1 1
Average 50 70 52 54 55 57 59 52 54 56 58 60
Wt~
Ethylene
Nordel
IP 4570
is available
from DuPOnt
Dow Elastomers
Tetrone
A (Dipentamethylene
thiuram
hexasulfide)
is available
from DuPOnt
Dow Elastomers
The procedure for determining green strength
of the blends in Table 48 was based upon ASTM D412 with
78
CA 02372056 2001-10-29
WO 00/69930 PCT/US00/13159
the following modifications. The blends were pressed
in a mold for 0.5 minute at 115°C. The mold was then
cooled for 2 minutes before pressed sheets were
removed. Pressed sheets were 1.91 - 21.6 mm thick.
Test samples were cut from the sheet using a die 12.7
mm wide by 114.3 mm long. The samples were stressed at
a rate of 127 mm/min. The stress at low strains (10 -
50 ~ strain) provides a good indication of "green-
strength" as defined in extrusion processes.
79
CA 02372056 2001-10-29
WO 00/69930 PCT/US00/13159
N
r
d0 N
N A1 m
\O f~7D
,~ OD 1D 1 r
ri
r
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X ' ~ ~
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r N ~O
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r
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JJ
W C7 cn .~ H U ~ ~ U
N + aW ~1 .w1E
m n
--
CA 02372056 2001-10-29
WO 00/69930 PCT/US00/13159
The formulations of Ex. 63-72 (Table 49) show
increasing hardness, 1000 modulus, and green strength
with increasing levels of interpolymers of the
invention. These increases are greater than would be
predicted by the blend's average ethylene level, as
compared to results achieved with a pure 50~ or 70°s
ethylene polymer. Consequently, higher hardness and
modulus levels can be achieved at lower average
ethylene levels. Lower ethylene levels provide
improved low temperature sealing performance as
measured by Temperature Retraction and Compression Set.
Ex 73-76 and Comn. Ex. AE- AF
Some applications require compositions of high
hardness (i.e. Shore D hardness greater than about 40).
Ex. 73-76 and Comp. Ex. AE-AF demonstrate that
compositions of the invention exhibit properties which
are advantageous for high hardness applications.
The interpolymer of Comp. Ex. AE is Nordel IP
4725P, an EPDM available from DuPont Dow Elastomers.
The interpolymer of Comp. Ex. AF is Nordel IP 4520,
another EPDM available from DuPont Dow Elastomers. A
comparison of compositional and physical properties for
the interpolymers of Ex. 1, 4 and 20 and Comp. Ex. AE
and AF is shown in Table 50.
The interpolymers of Ex. 1, 4, and 20 were blended
with Comp. Ex. AE and AF. The blends were prepared in
2 stages in a 1.2 liter internal mixer (Shaw - Intermix
KO). The filling coefficient was 64°s.
In a first stage, the masterbatch was prepared in
a semi-conventional method in which all ingredients
except sulfur, CaC03 and curatives were introduced into
the mixer at 40 rpm, then sulfur and CaC03 were
introduced 30 sec. before the Black Incorporation Time
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CA 02372056 2001-10-29
WO 00/69930 PCT/US00/13159
(BIT) and dumped 90 sec. after BIT or at 120°C. The
BIT is the time required to incorporate the filler
during the mixing operation. However, BIT is more than
just an indication of the mixing cycle time; it also
indicates mixing efficiency and filler dispersion rate.
On a plot of the mixing curve with time on the x-axis
and power on the y-axis, the power consumption reaches
a peak during the course of the mixing operation. The
time at which the power occurs is the BIT.
In a second stage, the sulfur and curatives were
added to the masterbatch in the internal mixer at
30rpm, then discharged after 2 minutes or at 11°C.
Table 51 shows the composition of the blends and Table
52 shows the blend ratios for the various polymers
used.
Table 50
Composition and Viscosity
Data
Physical Property Comp. Comp. Ex. Ex.20 Ex.
1 4
Ex. AE Ex. AF
Ethylene content 70 50 84.9 93.6 94.1
(wt~)
ENB content (wt~) 5 5 5.2 4.7 1.3
Crystallinity (~) 11 <2 20 37 39
Mooney Viscosity (MLI,a25 20 27 14 15
@125 C)
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WO 00/69930 PCT/US00/13159
Table 51
Composition
Data
Masterbatch Inc redient Quantit ( Time of Introduction
hr)
(1~' stage) EAODM 100 T=0
Carbon Black FEF 130 T = 0
- N550
Sun ar 2280 oil 45 T=0
Cao 5 T = 0
Zinc Oxide 5 T=0
Stearic Acid 2 T=0
Pol Eth leneGl col 1 T = 0
4000
Styrenic resin - 20 T=0
Pliolite S6H
Polyethylene wax 2 T = 0
- AC
617A
Sulfur 0.2 T=30 sec. Before
BIT
CaC03 40 T=30 sec. Before
BIT
Curatives Sulfur 2.8 T=0
(2"d stage) Zinc Eth 1 Phen 1 T=0
I Dithiocarbamate
N-Cyclohexylbenzothiazyl2 T=0
sulfenamide - CBS
TMTD 0.5 T=0
Tellurium diethyl 0.2 T=0
dithiocarbamate
-
TDEC
Vulkalent EC 0.5 T=0
TOTAL: 357.2
Carbon Black
FEF- N550
available
from Cabot
Corporation
Sunpar 2280
is a paraffinic
plasticizer
available
from Blaser
Swisslube
AG
Pliolite S6H
is available
from The Goodyear
Tire and Rubber
Company
Polyethylene
wax - AC 617A
is available
from Allied
Chemical
Vulkalent EC
is a sulfonamide
derivative
available
from Ba er
AG
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Table 52
Composition
Data
Ex. And Ex. Ex. 74 Ex.75 Ex.76
Comp. Ex. 73
Comp. Ex. 70 70 70 0
AE
Comp. Ex. 0 0 0 50
AF
Ex. 1 30 0 0 0
Ex. 4 0 0 30 0
Ex. 20 0 30 0 50
Table 53
Crystallinity
and Black Incorporation
Time Data
Property Comp. Ex. Ex. Ex. Ex. Ex.72 Ex.73
1
AE 70 71
Blend 11 20 14 19 19 19
Crystallinity
BIT (sec.) 157 360 180 170 185 180
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Table 54
Physical Property
Data
Measured PropertyStandardComp. Ex. Ex. Ex. Ex.75 Ex.76
AE 73 74
Used
Tensile Strength IS037 11.1 11.4 12 11.2 11.6
(Mpa)
+/-0.4
Modulus @ 10~ ISO 3.2 4.6 5 4.9 5.3
37
Elongation (Mpa)
+/-
0.2
Hardness, Shore ISO 39 44- 46 46 46
D +/-1 868
Tear Strength ISO 37 43 45 47 43
(kN/m) 34
+/-1 DieC
Comp. Set 70hrs ISO 48 55 48 49 44
@ 23C 815
+/-2
Comp. Set 22hrs ISO 93 91 88 Not 76
@ -lOC 815
+/-2 measured
TR10 (C) +/-1 ISO -23 -24 -22 -17 -31
2921
TR20 (C) +/-1 ISO -9 -11 -10 -2 -21
2921
The results in Tables 53 and 54 show that
incorporation of the interpolymers of Ex. 1, 4, or 20
into the interpolymers of Comp. Ex. AE and AF increases
the tensile strength, modulus, tear strength, and
hardness of the blends Ex. 73-76 over that of the Comp.
Ex. interpolymers. Hardness levels above about a 40(?)
Shore D permit such polymers to be used in high
hardness automotive or building weather-stripping
applications. For such applications, the mixing
operation has to be fast (productivity) and efficient
(good dispersion of the fillers is required so as to
match surface aspect requirements). Surprisingly,
blends of the inventive interpolymers with Comp. Ex. AE
and AF provided fast carbon black incorporation (short
BIT) and efficient mixing dispersion. In contrast, a
pure inventive interpolymer (Ex. 1) had a BIT
approximately twice that of the blended products.
CA 02372056 2001-10-29
WO 00/69930 PCT/US00/13159
One would expect compression set and low
temperature performance (TR) of Comp. Ex. AE-AF to
suffer with the addition of high crystalline material.
However, as Table 54 shows, both compression set and TR
values are essentially unchanged when the interpolymer
of Comp. Ex. AE is blended with the interpolymers of
the invention. When a lower crystallinity EAODM is
used (Comp. Ex. AF), but with a higher loading of high
crystalline material (Ex. 76) to obtain the same total
crystallinity of the interpolymer blends of Ex. 74 and
75, the low temperature compression set and TR values
actually improve considerably, even though the
interpolymer blend of Ex. 76 has the highest weight
percent of high crystalline material at 50 wt~.
Additionally, roll mill processing improved
considerably, as the compound provides better banding
on the equipment. Total crystallinity of the blends of
Ex. 74-76 remained constant at around 19~, which was
comparable to the interpolymer of Ex.1 at 20~
crystallinity. These types of properties find
applications in fields such as profiles, injection
molding parts, hoses, and belts where such improvements
are often advantageous.
Ex. 77 aad Comp. Ex. AG-AH
The interpolymer of Ex. 7 was injection
molded into 0.5 inch (12.7 mm) by 0.25 inch (6.35 mm)
bars for impact testing according to ASTM D 4020. These
bars were exposed to 5 Mrads e-beam irradiation to
produce irradiated interpolymer Ex. 77.
Comp. Ex. AG is a commercially available
0.962 density, 17.5 melt index, high density
polyethylene with Mn of 17,700 and Mw of 58,600
(ALATHON 6017 available from Equistar). Comp. Ex. AG
was injection molded under conditions similar to those
used to mold the interpolymer of Ex. 7. Comp. Ex. AH
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WO 00/69930 PCT/US00/13159
is a commercially available 0.25 inch (6.35 mm) thick
ultra-high molecular weight, HDPE sheet obtained from
Laboratory Supply Corporation and was cut into 0.5 inch
(12.7 mm) bars for testing. The irradiated
interpolymer of Ex. 77, along with an interpolymer of
Ex: 7 which was not irradiated, were tested for impact
strength along with Comp. Ex. AG and AH according to
ASTM D 4020, with the modification that a falling
weight was used instead of a pendulum. The falling
weight was 5.42 Kg and was dropped a distance of 73.66
cm. The impact energy was 39.2 Newtons.
Table 55 shows the impact strength of
interpolymers of this invention are significantly
better than the interpolymer of Comp. Ex. AG and AH.
Table 55 also reveals that irradiation at 5 Mrads
produces a vulcanized interpolymer having essentially
equivalent impact performance to the nonirradiated
interpolymer of Ex. 7.
Table 55
Impact Strength
Data
Ex. and Com Ex. Im act Stren th (kN/mz)
Ex. 7 124.5
Ex. 77 122.7
Com Ex. AG 4.8
Com Ex. AH 57.6
87
