Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~04~18S
This invention relates to thermoplastic polymer blends
of E:PDM polymer, polyethylene and ethylene-vinyl acetate co-
polymer .
BACKGROUND OF THE INVENTION
Polymer blends of ethylene-propylene copolymer or
ethylene-propylene-diene terpolymer with poly ~-olefins,
particularly polyethylene and polypropylene, are known to the
art (see U.S. Patent Nos. 3,361,850; 3,176,052, 3,220,966,
3,751,521; 3,328,486, 3,793,283: 3,262,992; 3,036,987; and
3,536,653). At times, curing or crosslinking agents are
added to alter the physical nature of the blend, i.e. to
effect chemical changes in the blend (see U.S. Patent Nos. ~
3,758,643, 3,806,558; 3,564,080, and 3,256,366). Polymer -
blends of poly ~-olefins or of ethylene-propylene or ethylene-
propylene-diene polymers with ethylene-vinyl acetate copolymers
are also known (~ee U.S. Patent Nos. 3,808,047; 3,422,055;
3,361,852, and 3,549,727). The use of curing or crosslinking
agents in these blends is disclosed in U.S. Patent Nos.
3,399,250, 3,789,085; and 3,784,668. None of the above cited
art discloses a three-part blend of ethylene-propylene-diene
polymer, polyethylene, and ethylene-vinyl acetate copolymer
wherein the blend, without the use of curing or crosslinking
agents, exhibits unexpectedly high tensile strength.
SUMMARY OF THE INVENTION
Thermoplastic polymer blends comprising an ethylene-
propylene-diene (EPDM) polymer having a high unstretched
crystallinity of at least about 10 percent by weight of the
polymer, a polyethylene (PE) polymer, and an ethylene-vinyl
acetate (EVA) copolymer are prepared by physically mixing
under heat and shear conditions the three polymer components.
--1--
.. .. ..... ..... .. . . . .. ....... .
,
,
1046185
The blendq exhibit ten~ile strengths greater than that ~ -:
pre~icted from the individual effects of the polymers.
No curing or cro~slinking agents are used to obtain the
superior tensile strengths.
More ~pecifically, the invention relates to a
thermoplastic polymer blend comprising (1) an EPDM polymer
consisting essentially of interpolymerized units of about
65 percent to about 85 percent by weight of ethylene,
about 5 percent to about 35 percent by weight of propylene,
and about 0.2 percent to about 10 percent by weight of a
diene monomer; said EPDM polymer having a weight percent ~.
unstretched crystallinity of from about 10 percent to about
20 percent by weight of the polymer and a melt endotherm
value of about 6 to about 10 calories per gram, (2) from about
5 parts to about 400 parts by weight per 100 parts by weight
of the EPDM polymer of a polyethylene polymer, and (3) from
about 5 parts to about 300 parts by weight per I00 parts by
weight of the EPDM polymer, of an ethylene-vinyl acetate co-
polymer.
~ " ,
;c~ -2-
10~ti185
DE~AILED DESCRIPTION OF THE INVENTION
The thermoplastic polymer blend of this invention
comprlses a physical mixture of three e~sential polymeric
components; i.e. ~n ethylene-propylene-diene polymer (EPDM),
a polyethylene polymer (PE), and an ethylene-vinyl acetate
copolymer (EVA). The blend comprises lO0 parts by weight of
EPDM, from about 5 parts to about 400 parts by weight of PE,
and about 5 parts to about 300 parts by weight of EVA. More
preferredly, the EPDM is present in 100 parts by weight, the
PE ln about 10 parts to about 200 parts by weight, and the EVA
in about lO parts to about 150 parts by weight.
The ethylene-propylene-diene polymers (EPDM) employed
have high unstretched crystallinity, ranging from a minimum of
about l ~ by weight to about 20% by weight based upon the
weight of the polymer. More preferredly, the unstretched
crystalllnity ranges from about 12~ to about 16~ by weight
of the polymer. The unstretched crystallinity of the EPDM
polymer is measured using an x-ray technique. Measuring
weight percent crystallinity in polymers via x-ray is a
known technique (see Natta et al, Atti Accad-Nazi. Lincei. -
Rend. (8) 8 ll (1957)). The method used herein consisted
of presæing a 0.020 inch thick film of the EPDM polymer at
120C and 20,000 pounds pressure. The films were quickly
cooled (quenched). The thin films are then mounted and
exposed to x-rays, and a defraction scan is made across an
angular range. Using a diffractometer, a plot of the angular
distribution o~ the radiation scattered by the film is made.
This plot is seen as a diffraction pattern of sharp crystal-
' llne peaks superimposed upon an amorphous peak. The quantita-
tive value of weight precent crystallinity is obtained by
dividing the crystalline diffraction area of the plot by the
total di~ractlon area on the plot.
1046185
The EPDM polymers also exhibit a large melt endo- -
therm of from about 6 to about 10 calories/gram. The melt
endotherm is measured using a Differentlal Scanning Calori-
meter (DSC) sold by DuPont as the ~uPont 900 Thermal Analyzer.
The test measures orientation within the polymer. A completely
amorphous EPDM terpolymer would have a zero melt endotherm.
The test consists of placing a polymer sample of known
weight into a closed aluminum pan. DSC Cell calorimeter
pans supplied by DuPont were used. The polymer sample is
then heated at a rate of 10C/minute over a temperature range
of from -100C to +75C. The reference material used is
glass beads. me DSC chart is precalibrated, using metals
with known heats of fusion, to provide a chart having a unit
area ln terms of calorles/square lnch/minute. As the polymer
8ample is heated, a crystalllne melt point peak will show on
the chart. The area under the crystalline melt point peak
is measured, and the melt endotherm in calories/gram ls
calculated from the area obtained.
The EPDM polymer is comprised of interpolymerized
units of ethylene, propylene and diene monomers. The ethylene
forms from about 65% to about 85~ by weight of the polymer,
the propylene from about 5~ to about 35~ by weight, and the
diene from about 0.2% to about 10% by weight, all based upon
the total welght of the EPDM polymer. More preferredly, the
?~5 ethylene conten~ is from about 70~ to about 80% by weight,
the propylene content is from about 15% to about 29% by
weight, and the diene content is from about 1% to about 5%
by weight o~ the EPDM polymer. Examples of the diene monomers
are: conJugated dienes such as isoprene, butadiene, chloro-
prene, and the like; and noncon~ugated dienes, containing
from 5 to about 25 carbon atoms, such as 1,4-pentadiene,
1,4-hexadiene, 1,5-hexadlene, 2,5-dimethyl-1,5-hexadiene,
~4f~185
1,4-octadiene, and the like, cyclic dienes such as cyclopenta-
dlene, cyclohexadiene, cyclooctadiene, dicyclopentadiene, and
the :Llke; vin~l cyclic enes such as l-vlnyl-l-cyclopentene,
l-vinyl-l-cyclohexene, and the like; alkylbicyclonondienes
such as 3-methylbicyclo(4,2,1)nona-3,7-diene, 3-ethyl-bicyclo-
nondiene, and the like; indenes such as methyl tetrahydro-
indene, and the like; alkenyl norbornenes such as 5-ethylidene-
2-norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-norborn-
ene, 2-isopropenyl-5-norbornene, 5-(1,5-hexadienyl)-2-norborn-
ene, 5-(3,7-octadieneyl~-2-norbornene, and the like; and tri-
cyclo dienes such as 3-methyl-tricyclo(5,2,1,02~6)-3,8-decadiene,
and the like. The more preferred dienes are the nonconjugated
dienes. Particularly good results are obtained when alkenyl
norbo menes are used as the diene monomer.
The presence of interpolymerized diene monomer in
the EPDM polymer is a necessary feature of the EPDM polymer.
It was found that blends of EP(ethylene-propylene) polymers
with polyethylene polymers did not exhibit the unexpectedly
high tensile strengths which characterize-the blends of the
invention. The type of diene monomer used is not critical
as long as the EPDM polymer employed has high unstretched
crystallinity.
The EPDM polymers are readily prepared using suspen-
sion and solution polymerization processes and techniques well
kno~n to the art.
The EPDM polymers are high molecular weight, solid
elastomers. They have a dilute solution viscosity (DSV) of
about 1.6 to about 2.5 meaæured at 25C as a solution of 0.2
gram of EPDM polymer per deciliter of toluene. The raw
polymer has a green strength tensile of about 800 psi to
about 1800 psi, and more typically, from about 1000 psi to
about 1600 psi, and an elongation at break of at least about
1046185
600 percent.
The polyethylene employed in the blend can be a low
(to about 0.94 grams/cc.) density, medium (about 0.94 grams/cc.
to about o.~6 grams/cc.) density, or high (above about o.g6
grams/cc.)density polyethylene. The low density polyethylenes
are more preferred as they provide actual tensile reinforce-
ment between the polymers. The polyethylen~ have a melt
index of from about 0.2 grams/10 minutes to about 30 grams/
10 minutes measured at 190C under a 2.16 kilogram load.
If a low density polyethylene is used, the melt index is
preferredly below 7 grams/10 minutes. The polyethylenes are
commercially available, and can readily be prepared using
standard solution polymerization techniques known to the art.
As mentioned before, the polyethylene is used at from about 5
parts to about 400 parte by weight with 100 parts by weight of
the EPDM polymer. Particularly good results are obtained when
the PE is used at about 10 parts to about 200 parts by weight
with 100 parts by weight of EPDM polymer.
m e ethylene-vinyl acetate copolymers employed in
the polymer blend have a melt index of from about 0.4 gram/10
minutes to about 30 grams/10 minutes measured at 190C
under a 2.16 kilogram load. More preferredly, the melt
index is from about 1 gram/10 minutes to about 10 grams/10
minutes. The copolymer contains interpolymerized units
f from about 50% to about 90% by weight ethylene and about
10% to about 50% by weight of vinyl acetate, based on the
total weight of the copolymer. A more preferred range is
from about 70% to about 85~ by weight ethylene and about 15%
to about 30~ by weight of vinyl acetate. As mentianed above,
the EVA copolymer is used at 5 parts to about 300 parts by
weight with 100 parts by weight of the EPDM polymer. Particu-
larly good results are obtained using the EVA at from about
1~4f~8S
10 parts to about 150 parts by weight with 100 parts by weight
of the EPDM polymer.
The composition o~ the invention comprises a
physical blend of EPDM polymer, polyethylene polymer, and
an ethylene-vinyl acetate copolymer. No cure or crosslinking
agents are employed. It was totally unexpected that the
thermoplastic polymer b~end of the three polymeric components
would exhibit a tensile strength greater than that predicted
from the individual effects of any one component alone. It
was further unexpected that the use of low density PE and EVA
with the highly crystalline EPDM would yield blends having
higher tensile strengths in the blend than the tensile strength
of any one polymer alone.
The polymer blends are truly thermopla~tic, moldable
and remoldable at temperatures of above 120C, preferably at
above 140C to about 200C, yet having a strong, flexible
plas~ic nature at room temperatures.
A wide range of rubber and plastic compounding ingred-
ients are readily mixed with the thermoplastic polymer blends
using mixing equlpment such as two-roll mills, extruders,
banbury mixers, and the like. Standard mixing and addition
techni~ues are used. In many cases, the addition of compound-
ing ingredientæ, particularly waxes, plasticizers and extenders,
can detract from the overall tensile strength of the thermo-
plastic blend. Reinforcing fillers such as fumed æilicas
provide increased ten~ile strength to the blends.
Examples of compounding ingredients are metal oxides
like zinc, calcium, and magnesium oxide, lead monoxide and
dioxide, fatty acids such as stearic and lauric acid, and
salts thereof such as cadmium, zinc and copper stearate and
lead oleate; fillers such as the carbon blacks like channel
blacks, high rein~orcing blacks as NllO and N330, low rein-
' ' ~ ' -':
104~i~8S
forcing blacks as N550 and N770, and thermal blacks as N880
and N990, calcium and maB esium carbonates, calcium and
bari~m sulfates, aluminum silicates, phenol-formaldehyde
and polystyrene resins, asbestos, and the like; plasticizers
and extenders such as dialkyl and diaryl organic acids like
diisobutyl, diisooctyl, diisodecyl, and dibenzyl oleates,
stearates, sebacates, azelates, phthalates, and the like;
ASTM type 2 petroleum oils, ASTM D2226 aromatic, naphthalenic
and paraffinic oils, castor oil, tall oil, glycerin, and the
like; antioxidants, antiozonants, and stabilizers such as
di-~-naphthyl-p-phenylenediamine, phen~ naphthylamine,
dioctyl-p-phenylenediamine, N-1,3-dimethylbutyl-N-phenyl-p-
phenylenediamine, 4-isopropylamino diphenylamine, 2,6-di-t-
butyl paracresol, 2,2'-methylenebis-(4-ethyl-6-t-butyl phenol),
2,2~-thiobis-(4-methyl-6-t-butyl phenol), bisphenol-2,2'-methyl-
enebis-6-t-butyl-4-ethylphenol, 4,4'-butylidenebis-(6-t-butyl-
m-cresol), 2-(4-hydroxy-3,5-t-butylaniline)-4,6-bis(octylthio)-
1,3,5-triazine,hexahydro-1,3,5-tris-~-(3,5-di-t-butyl-4-
hydroxyphenyl) propionyl-s-triazine, tris-(3,5-di-t-butyl-4-
hydroxybenzyl) isocyanurate, tetrakismethylene-3-(3', 5'-
di-t-butyl-4'-hydroxyphenyl)propionate methane, distearyl
thiodipropionate, dilauryl thlodipropionate, tri(nonylated-
phenyljphosphite, and the like; and other ingredients such
as pigments, tackifiers, flame retardants, fungicides, and
the like. Such ingredients are used in levels well known
to those skilled in the art.
Applications for the thermoplastic polymer blends
include tubing, llners, wire and cable insulation, mats, and
molded items such as æhoe soles, toys, kitchen ware, and the
like.
The polymers used and the thermoplastic blends were
evaluated for their stress-strain properties; i.e. tensile,
--8--
1046185
modulus, and elongation, following ASTM procedure D638
(using a pull rate of 20 inches/minute). Hardness was
measured ~ollowing ASTM D2240.
The following examples are presented to ~urther
illustrate the invention. Unle~s otherwise stated, the
ingredient~ recited ln the recipes are used in parts by weight.
EXAMPLES
The polymeric components of the blends, along with
compounding ingredients, if used, were mixed together using
a two-roll mlll. The roll ratlo was 1.2 to 1 and the front
roll has a roll speed of 21 rpm. Front roll temperature was
150C with the back roll sllghtly cooler. The EPDM was banded
on the mill and the other polymeric and compounding ingredients
(if used) added to the banded polymer. Mill tlme was ab~ut 5
minute~ in all cases.
The mixing condltlons and temperatures outllned above
are not critical. The important factor is to get uniform dis-
perslon of the polymers and ingredients ln the thermopla~tic
blend. This can be accompllshed using other equlpment, such
as a banbury mixer, by mlxlng at other temperatures and for
other times, and the like; all of which conditions and proce-
dures are well known to the artisan. The above conditions were
used to achieve good, thorough mixing, and are outllned to
illustrate the preparation of the physlcal blends.
EXAMPLE I
An EPDM polymer (EPDM-l) having a hlgh unstretched
- cry~tallinity was blended with a low denslty PE and an ethyl-
ene-vinyl acetate (EVA) copolymer. The blend was evaluated
for its tenslle and elongatlon following ASTM D-746. For
comparatlve purpo~ss, three other EPDM polymers havlng a low
unstretched crystallinity were indlvidually blended wlth the
same PE and ethylene-vinyl acetate copolymer~ and the blends
~ 046185
evaluated. The polymeric components are identified in the
following table:
--10--
1046:185
Q) N L~
~ ~ O
:5 H r~
O
~1 ~
~ ~1 :
. ~
O : '
a~
0 o~
:
~1
O N C`J C~l ~) I
~:
Ln o c~
~ '0
~O
~ CQ H H N
~ ~ 0~ C~.l P P
a) o o ~
~ l ~ ~ ~
a~ v v ~o
~i CU t'~ .i ~ H H
~ V~l ~1 p p ~
~ ~ N ::~ O O
O I 1' 1 0 0
~ :
f~ O
U~ ~1
--11--
- : '` ' :
1046~85
The polymers were mixed on a two-roll mill at a mill
temperature of 150C. All of the sample compositions formed
good bands on the mill. The compositions were sheeted off of
the mill and pressed ~ 177C in a tensile sheet mold prior to
cutting the tensile test samples. The compositions were pre-
pared according to the following recipes. Tensile samples
were pulled at a rate of 20 inches/minute. Control samples
of the polymers alone were also tested for their tensile
strength and elongation.
-12-
lQ46185 ~
o ~ ~ o o
, , , o
~1, , o I ~ ~ ~ o
I ,, ~ ~ ~ o~
~1 o ~ ~ o o
N I o I I ~ ~r) C~ L~
~1 ~ L~
~1 :
l O ~ ~ O O
~1 O I I I tr) ~) ~Q N
~0~ ~0 ~0 ~0 ~0 0 0
C O 0 0~ 0 0 U~ O
co C~ ,0~
. ',
~r ::
S~
O L~ O O O O
u~ bD O C`.l O O O`~ O :
~1 ~ O U~ C~J O ~1
~1 ~1 C~l C~l ~
,.
~d
CQ .,1
tQ ~ ~d
~` ~ bD
bD ~
O tQ ~ ~
~1
-1 N ~ ~ ~ ~æ ~1 a~
~ ~ ~ ~ ~ ~ ~l ~ ~l
m E~
.
~ ~ .
-13-
.. . . ~ .
~(~4618S
The data shows that EPDM-1 is unique in its ability to
prepare thermoplast~c blends having eXceptional tensile strength.
The measured tensile strength of Sample I, a composition of the
preserlt invention, is unexpectedly higher than that of any
of the other blends, and is actually higher than the tensile
strength of any one of the polymer components employed. No
curatives or curing agents are employed in the blends.
EXAMPLE II
The experiments in Example I were repeated using
still more types of EPDM polymers. The following table presents
the data obtained, which data again shows the unique property of
the highly crystalline EPDM polymers to prepare thermoplastic
blends of hlgh tensile strength.
Melt Weight ~ Monomers
(calories~gm) Et~Yle~e- Propvlenç Dlenea
EPDM-l 8.4 73 23 4
EPDM-5 0.3 69 23 8
EP-6 4.8 68 32 0
EP-7 - 75 25 0
EPDM-8 - 58 38 4
EP-9 None 50 50 0
a Diene used is 5-ethylidene-2-norbornene
-14-
~4~;185
o ~ ~ o o
, , , , , o ~ ~ U~ ,,
o ~ ~ o o
o ~ ~ o o
, , , o , , ~ ~ ,, ..
~ ,, 0 ~
a)
m I o ~ ~ o o
I I o I I I ~ ~ ~I 00
~ ~ ~D
o - ~ ~ o o
N I O I I I I t~ ~~1
,~
O ~ ~ o o
O h
''I 2~
bDO~I O O O O O O o o
C O O N O 00 0 0 U~ O
O P~ ~
O O O O O L~ ' O O
O _I O OO ~ 11~ N (J~ O
Q C~ i O r-l
E-l ~ w ~I NCU c~
.,1 ~
~ ~ ~
~ ~ bD
S~ ~,
4 P~ ,¢
O M O ~d
O
~1
o ~ ~ ~~Q 4
W W ~ g ~ ~
O Lt~
L
-15-
.
- ` ~
~346~S
EXAMPLE III
The highly crystalline EPDM polymer was mixed with
three types of ethylene-vinyl acetate copolymer and PE polymer.
All of the blends showed excellent tensile strengths, demonstra-
ting that the thermoplastic polymer blends can be prepared using
a wide range of ethylene-vinyl acetate copolymers.
1 2 3
EPDM-l 100 100 100
PE-NA301 20 20 20
EVA-UE630a 20
EVA-UE634b - 20
EVA-UE643C - - 20
Tensile Strength,psi 2350 2430 2160
Elongation, percent 760 750 760
a 82% ethylene/18% vinyl acetate copolymer
having a melt index of 1.5 g/10 min. at
190C and a tensile strength of 2100 psi
b 72~ ethylene/28~ vinyl acetate copolymer
having a melt index of 3.0 g/10 min. at
190C and a tensile strength of about
175~ psi
c 81~ ethylene/19% vinyl acetate copolymer
having a melt index of 9.0 g/10 min. at
190C and a tensile strength of about
1600 p8i
EXAMPLE IV
A highly crystalline EPDM polymer was mixed with a
number of different types of polyethylene (PE) polymers and
an EVA copolymer. All of the thermoplastic blends exhibited
excellent tensile strengths. The polymers used are identified
as follows:
-16-
~046185
.,,
~ c) ~
bD ~ O O O O O U~
~ ~ ~1 0 U~ Lr~ ~ C~J I
O Q
~q
P O
_ ~ O
O O O O O ~ O
bl O O O~ C~J O O
Lr\ ~1 0 o~) oo ~ OC~
E~ ~ ~ I g
U~
a
VVVV VV
o o o o o o ~
~_ OOOO OO ~q
a~ ~ ~ O~
~r C~
~ C
~1 Lr~ 0 ~
~1~ CU U~ CUIn 00 cu N
o ~i ~ ~i N q-
P~
~ .
~,_ a
_ O O O O O O O 1~ !
td :,:
.
o o cc ~
~ ~l o o ~
Q~ ~ ~,
~ p ~ ~ ~ ~ ~
--17-
1~)4~185
2 3 4 5_ _
EPDM-l 100 100100 100 100
EVA-U~630 10 10 10 10 10
PE-NA301 10 - - - -
PE-DND2004 - 10
PE-C14 - - 10
PE-LS630 - - - 10
PE-IB733 - - - - 10
Tensile,psi 269027602610 2890 2710
Elongation, 710 750 730 680 720
percent
Samples, 1, 2 and 3 employ low density polyethylene
(PE) polymers. The tensile strengths of the blends are above
that of any polymeric component used alone. Samples 4 and 5
employ high density PE polymers. The tensile strengths o~ the
blends are above that whic h would be predicted using a method
whereby each polymer contributes added tensile strength to the
EPDM polymer in proportion to its weight percent o~ the total
blend. Using this method, the predicted values of Samples 4
and 5 would be (1500 + 250 + 50) = 1800 psi and
(1500 ~ 190 + 50) = 1740 psi, respectively. As the data shows,
the tensile values obtained from the blends are about 1000 psi
over the predicted values.
EXAMPLE V
A wide range of parts by weight of PE polymer and parts
by weight of EVA copolymer can be used with the highly crystal-
line EPDM polymer to prepare the unique thermoplastic blends.
Blends of highly crystalline EPDM, a low density PE, and EVA
polymer were prepared using procedures and techniques as des-
cribed before. The thermoplastic blends were then evaluated
~or their tensile strength. Recipes used and data obtained are
as follows:
--18-
1'~46185
~1 o ~ ~ o o
,, o
~I N t~ C~
N
~1 ~ ~ O
O ~ ~ L~
~1 ~ C~J
N
~1 0 0 ~ O O
~1 O ~ :;1 ~ m
N ~
O l O ~r)~) O O
~_1 O .J
~1 ~I C~l
C~
I O O O O O
0~ O O O ~ ~)
N
O O O O O ,~
0 O 1~ ~)OQ ~ ~ .~ .,
I bO N ~
O O O o o ~ ~ O
~_ O ~) ~ In It~ a) cq ~ q~ O
rl C~.l C~ ~ a) o ~ a
O ~ ) O O ,~
~) O ~ ~ ~ ~ ~ ~rn N ~ Q~ ~
~1 ~) r~ q o o r-l
O O t-- o o ~ o~
IS~ O L~~ ~ U~~ bD O O
~1 ~ ~ ~ 4 ~)V ~1 ~ O ~ - :
CU O ~ ~ ~ ~D .. :
~ O S~ ':
O ~ O O O ~1 ,~ ~ ) O O
~t 0 ~ 1 ~ ~ O~: ~ 0 ~1 .C C) ~
O ~ 0~0 0 ~ 0 ~ ~ 0 ~
~r O ~I C~0 ~O ~ O ~ ~ U~ ~ ~ O CQ
~1 ~ ~ ~ Q~ O ~ O 0 ~1
N C\J ~ rl
a~ O o ~ I O o ~~
N O N --I ~I ~ ~ Cq
'I ~ ~~I St Q. ~1 ~ ~ O ~1 o
N P~ O~ O ~ h ~ ,1 0
S ~: O~ a3 ~ ~ ,~ ~ ,1
O N N O O a) 0=~ bD ~D
~1 O ~I rl(~ ~r) P ~
O ~ o lS~ ,,
N ~ 0 ~0~ ~ ~1 N ~
O~ bD ~ a) 0 ~ a) ~1
.
~R S '' '
O
b
O S~
O
-19-
lQ46185
EXAMPLE VI
This example continues the showing of Example V wherein
a broad weight range of PE and EVA polymers was used with the
EPDM polymer. Herein, data is presented showing thermoplastic
polymer blends having high weight levels o~ PE polymer to low
weight levels of EVA copolymer, and vice versa. High levels
of PE polymer to low levels of EVA copolymer in the blend
yields excellent results. However, the data shows that the use
of over about 200 parts by weight of PE polymer per 100 parts
EPDM polymer and 10 parts EVA copolymer is not necessary to
obtain the benefits o~ the present invention. In contrast,
the use of high levels of EVA copolymer to low levels of PE
polymer detracts from the tensile strength of the blend.
The use of over about 200 parts by weight of EVA copolymer
per 100 parts EPDM polymer and 10 parts PE polymer is not
preferred when maximum tensile strength of the blend is
desired.
-20-
1046185
I o o o o o
o ~1 In U~
,, ~ ~ ~ , ~ .
bD h :;
UO~ g ~~ P
~ o 0 ~1
g UO~
~1 ~ ~ ;
h 5:: ~
g a~ 5~0
N e~ In
,~
~I g 1n - ~ ~ w ~ o
N ~5 a) O
o o N ~ ~ ~
q) ~1 00
-~ 1 g O ~ h
~, ~
~ ~ W~
W ~ E~l W ~
Lt~ O
--21--
,, ~,
1~)46185
EXAMPLE VII
The previous examples show that a broad range of
different types of PE polymer and EVA copolymer can be mixed
with a highly crystalline EPDM polymer to obtain thermoplastic
poly~er blends having unexpectedly superior tensile properties.
Many standard rubber and plastic compounding ingredients can
be admixed with the thermoplastic blends to yield attractive
and functional molded items. These ingredients include
particularly antioxidants and stabilizers, fillers and reinforc-
ing agents and plasticizers and lubricants. It has been found,though, that the addition of lubricants can detract from the
final tensile strength of the thermoplastic blend. me follow-
ing data shows tensile strengths of blends having a filler and
a lubricant used therein.
1 2 3
EPDM-l 100 100 100 -~
PE-NA301 50
PE-DND2004 - 20 20
EVA-UE630 25 20 20
HiSil/233a 50
Aristowaxb - - 1 .
Tensile,psi 2420 23902030
Elongation, percent 590 700 680
a Precipitated hydrated silica
b Process lubricant, paraffinic wax having
a melting point of 165F
-22-
:, ., : .
~ ,
