Note: Descriptions are shown in the official language in which they were submitted.
7~
Elastomeric thermoplastics are well known, see U.S. Patents
3,758,643 and 3,835,201 (Fischer).
Such elastomeric -thermoplastic blends are used -to produce molded
or extruded articles, such as automotive decorative and struc-tural parts.
Such parts may also be paintable, see U.S. Pa-tent 3,873,348 (Reilly et al).
In order to achieve sufficient melt flow properties for process-
ing, such e].astomeric thermoplas-tics for molding and extruding purposes have
generally been limited to low molecular weight materials obtained either
directly through polymerizaiton or indirec-tly through the breakdown of higher
molecular weight materials duri.ng processing.
The present invention permits the use of high molecular weigh-t
elastomeric materials without polymer breakdown by incorporating therein a
plasticizer such as a hydrocarbon oil. Processing as well as mechanical
properties of the resulting blends have also been improved in the present
invention by use of carbon black having high reinforcing capacity and low
aggregate s-tructure.
According to the invention, there is provided an elastomeric
thermoplastic comprised of:
(a) about 85 to 30 parts by weight of an elastomeric copolymer
of ethylene and at least one other C3 to C10 higher alpha
olefin, or an elastomeric terpolymer of ethylene, at least
one other C3 to C10 higher alpha olefi.n and a C5-C14 noncon-
jugated diolefin;
(b) about 15 to 70 parts by weight of a C2 to C8 crystalline
polyoleEin; and
(c) about 5 to 150 (preferably 5 to 100) parts of hydrocarbon oil,
per 100 parts of said elastomeric copolymer or terpolymer,
selected Erom the group consisting ofnaphthenic and paraffinic
- 2 -
'
7~:~7
oils .
In a preferred embodiment of the invention, there is also present
in the compositon a carbon black having high reinforcing capacity and :Low
aggregate structure, preferably in the amount of about 10 to about 120 parts
per 100 parts of elas-tomeric copolymer or terpolymer. The blending procedure
is such that the carbon black is incorporated primarily in -the elastomeric
phase.
It has also been found that a plasticizer such as naphthenic or
paraffinic oils can be blended with such thermoplastic blends to obtain good
viscous or melt flow properties as opposed to ob-taining such properties by
conventional means, i.e., by using polymers of low viscosity obtained through
polymer breakdown or molecular weight limitation. If a plasticizer is used,
it is preferred that it be blended in the elas-tomer phase before said plas-
ticizer/elastomer blend is subsequently blended with the crystalline polyole-
fin. It is also within the scope of this invention that the plasticizer can
be used in conjunction wi-th any conventional filler although for best results
it is preferred that it be used in conjunction with a black having high
reinforcing capacity and low aggregate structure.
The thermoplastics of the instant inven-tion are useful for molded
2~ and extruded articles such as injection molded automotive decorative and
structural parts.
The ethylene/higher alpha olefin copolymers and terpolymers may
be prepared by any conventional manner and the preparation of same does not
constitute part of the instant invention.
The preferred ethylene/higher alpha olefin copolymer is ethylene
propylene rubber hereinafter re~erred to as EPR. The preferred ethylene/
higher alpha olefin terpolymer contains e-thylene, propylene, and ENB (5
e-thylidene-2-norbornenel, said terpolymer being hereinafter referred to as
- 3 -
7~'~
EPDM. Such copolymers con-tain about 20 to about 90 mol percent, preferably
about 30 to about 80 mol percent ethylene and about 90 to abou-t 20 mol percent
preferably about 80 to about 30 mol percent propylene, wherein the terpolymers
contain about 10 to about 90 mol percent ethylene, about 90 to about 10 mol
percent propylene, and up to about 30 mol percent ~NB.
The co- and terpolymers suitable for use in the instant invention
have a number average molecular weight as measured by membrane osmometry o:E
about 25,000 to about 1,000,000, preferably about 50,000 to about 500,000 and
mos-t preferably about 75,000 to about 350,000.
Crystalline polyolefin resins suitable for use in the instant in-
vention are those high molecular weight resins prepared by polymerizing such
olefi.ns as ethylene, propylene, bute.ne-l, pentene-l, 4-me-thyl-pentene, etc.
Preferred is polypropylene having less than about 12 weight ~.i soluble polymer
in boiling heptane. Crystalline block copolymers of ethylene and propylene
can also be used. Included among the polyolefin resins are the higher alpha
olefin modified polyethylenes and polypropylenes.
The preferred carbon blacks employed in -the instant invention are
those blacks which have high reinforcing capacity and low aggregate structure.
Preferred are the high abrasion Eurnace blacks (HAF), preferably, a low struc-
ture high abrasion furnace black (HAF-I.S). Blacks suitable for use in the
instant invention are -these:blacks having a par-ticle size of abou-t 100 to about
600A, preferably abou-t 200 to abou-t 450A, and a surface area of about 25 to
about 150 m /g, preferably about 40 to about 100 m /g.
The high reinforcing blacks used in the practice of the present
invention generally give a product with improved physical properties over
those products prepared with low reinforcing blacks~ That is, such physical
properties as extensibility, tensile product and heat distortion are improved
by use of high reinforcing blacks. To obtain a blend of -this invention with
. ~ - 4 -
~3~
improved processing proper-ties as judged by spiral flow, it is necessary to
use a low structure black. Therefore, it has surprisingly been Eound -that
not only can the physical properties of the blend of the instant invention
be improved but also the processing properties of such a blend can be improved
by incorporating therein a black having both high reinforcing proper-ties as
well as having low structure such as E~AF-LS.
It is also a feature of this invention that when an HAF-LS black
is incorporated into the instant blends, a higher bound rubber conten-t is
obtained, as opposed to similar blends incorporating the same amount of a
general purpose furnace black (GPF) or any other conventiorlally used carbon
black. Higher bound rubber content gives more carbon-polymer interaction,
for example, more carbon-polymer bonding. This is desirable because it leads
to enhanced rubber-like properties, that is, properties resembling those of
partially vulcanized rubber. See A.M. Gessler, Rubber Age, 101, 55 (1969).
It has also surprisingly been Eound that HAF-LS blacks rather
than other conventional blacks such as GPF blacks are more readily blended
with the blends of the ins-tant invention. This is surprising owing to the
fact tha-t it is generally accepted by those of ordinary skill in the art that
it is easier to blend carbon black with an elastomer when the black particle
is iarge and -the black structure is high. Thus, it would be assumed that a
GYF black rather than an MAF-LS black would blend more readily with the b]ends
of the instant invention. It will be noted that -this blendiny advantage of
HAF-LS black occurs at all black concentrations above 35 php, regardless of
the ethylene propylene copolymer or terpolymer used.
An important aspec-t of the blends of the instant invention is
their paintability by conven~.ionalmethods regardless of the use of oil for
plasticization. Ordinarily, oil would not be blended with crystalline poly-
olefins such as polyethylene and polypropylene, owing to -the fact that when
.
.
!
~3~ 7
oil is blended with such polyolefins above -the melting point of the polyolefin,
the oil "bleeds" to the surface on recrystalliza-tion. The ins-tant inven-tion
gives a product whose surface is oil free and paintable by conventional
methods. One such method suitable for use for painting the elastomeric
thermoplastics of the instant inven-tion is to clean -the molded parts of the
instant inventionby either wiping wi.th a solvent or power washing with a 1.5%
solution of Ridoline*72 followed by several rinses The last rinse is with
deionized water to remove all traces of dirt, mois-ture, oil, fingerprints,
release agents, plas-ticizers, etc. The molded parts are -then dried and treat-
ed for coating adhesion either with a proprietary material produced by Seibert
Oxiderm* (~P1006) which contains a chlorinated polyolefin, or by ultraviolet
surface treatment~
Following this surface treatmen-t -the parts are primed with either
a lacquer primer such as Durethane*, Lacquer Primer 32906 or an enamel primer
such as Durethane* enamel primer 33104 or 33198. ~lthough these primers are
not essential, they are commonly used in production for masking -the black
substrate. The pri.med surface is baked for about 20 minutes at about 240 F
and then top coated with either PPG's series (flexible polyurethane~ or
DuPontls Dexlar* series (flexible acrylic enamels). The top coated surface
is then baked for about 30 to about 40 minu-tes at about 250 F. It is preferred
that the primer be applied in two coats to give a primer coat thickness of
at least 0.8 mils and the -top coat applied ln three coat.s to give a top coat
thickness of at least 1.8 mils.
The elastomeric thermoplastics of the instant invention are also
paintable by conventional electrostatic paint application methods owing to
their acceptable volume resistivi.ty. At 31% black, based on the total weight
of the blend plus black, the volume resistivity is 10 ohm cm. This is an
* Trade Mark
-- 6 --
~ .
~ffl3~72~
acceptable resistivity Eor conventional electrostatic paint application
methods.
It is some-times desirable that very high molecular weight ethyl-
ene-propylene copolymers or terpolymers be used in the blends of the present
invention. These high molecular weight EP polymers are useful for exterior
automotive pàrts that require the strength, resilience, toughness, etc., which
would ordinarily only be obtainable through the use of a vulcani~ed rubber.
Such high molecular weight polymers were heretofore unsatisfac-tory owing to
the fact that their viscosity and rheological properties were unsuitable for
1~ yielding the qood processing or ho-t flow properties needed to assure proper
injection molding of such blends.
It has surprisingly been found that when about 5 to about 150 php,
preferably about 5 to about 100 php, and more preferably abou-t 10 to abou-t
80 php (based on 100 parts of EP copolymer) of a hydrocarbon oil such as a
naphthenic and/or a paraffinic oil is incorporated into high molecular weight
EPDM/crystalline polyolefin blends, said blends are more readily injection
molded owlng to their improved viscosity and rheological properties. During
the blending procedure, it is preferred tha-t a substan-tial portion of the
oil be uniformly dispersed in the elastomeric phase prior to hlending with the
crystalline polyolefin.
The use of oil in the present invention is~therefore advantageous
in various ways. One is that it removes the viscosi-ty limitation which had
previously been associated with ob-taining satisfactory processing bebavior of
the elastomeric thermoplastic, thus permitting the use of high molecular weight
EP co- and/or -terpolymers with structural properties need for various products
such as exterior automo-tive par-ts. Another is that it substitutes oil for
polymer breakdown as a rneans for adjusting viscosity, thus giving an economic
advantage. It has been found -that the use of oil with a high molecular weight
_ 7 _
~ .,
.. ~ ~ .
. . . ~
~ . - , .
EP co- and/or terpolymer when blended with a crystalline polyolefin resin as
taught in the pxesent inven-tion gives a product with improved physical prop-
erties such as improved resilience and significantly enhanced ex-tensibility,
regardless of the type carbon black used. But it will be noted that such
properties are maximized when the carbon black is an IIAF-LS black as previously
described.
It will he noted -that when the aforementioned hydrocarbon oils
axe used in the instant invention, any conventional filler may be used,
although the preferred filler is carbon black and the most preferred is a
carbon black having high reinforcing capacity and lowaggregate struc-ture.
Nonlimiting examples of nonblack fillers suitable for use in the
instant invention when a hydrocarbon oil is used include inorganic inert mater-
ials and organic coupling agents. Illustrative of such inorganic inert mater-
ials are ground and precipitated calcium carbona-te; standard, delaminated,
calcined, and hydrated Kaoline clays; precipitated, hydrated silicas; and
silicates, especially calcium and magnesium silicates. Illustrative of the
organic coupling agents suitable for use in the instant inven-tion include the
halo-silanes, titanates, etc.
Nonlimiting examples of carbon blacks suitable for use in the
2~ instant invention when a hydrocarbon oil is used include the channel blacks
such as MPC and CC; the furnace blacks such as SRF, HMF, CF, FF, E~AF, ISAF
and SAF; and the thermal blacks such as MT and FT.
The unvulcani~ed elastomeric -thermoplastic blends of the present
invention generally contain about 85 to about 30 parts, preferably about 80
to about 50 parts of oil-containing e-thylene co- and/or terpolymer, and about
15 to about 70 parts, preferably about 20 to about 50 parts of crystalline
polyo]efin. The crystalline polyolefins may be a single homopolymer or a
mixture of crystalline polyolefins, e.g., polypropylene or a 50/50 blend of
~l --8--
.~
2i7
polypropylene and polyethylene.
Suitable amounts of HAF-LS black when incorporated into the blends
of the instant invention are preferably about 20 to about 200 parts, more
preferably about 30 .o about 120 parts, and most preferably about 35 -to about
80 parts ba~sed on the oil-containing ethylene co- and/or terpolymers.
Also within the scope of the present invention is a two phase
elastomeric thermoplastic material con-taining the ethylenic co- and/or ter-
polymer, the crystalline polyolefin, and thehydrocarbon oils as described
previously herein. The surprising and significan-t fea-tures of the instant
two phase thermoplastic material is that both phases are continuous and the
mean dis-tance between phase boundaries is less than about 1 micron.
Ordinarily thermoplastic blends similar to the instant thermo-
plastic blends are composed of two phases wherein one phase is con-tinuous and
the other phase discontinuous and therein the mean distance be-tween the phase
boundaries is more than about 1 micron. By controlling the polymer type,
composition, molecular weight and/or the use of plasticizing oils, it has
surprisingly been found that a two phase thermoplastic is produced wherein
both phases are continuous and wherein the mean distance between the phase
boundaries is less than about ] micron.
The two phase structure of the blends was determined by injection
molding a specimen and subsequently extrac-ting the amorphous phase wi-th boiling
n-heptane for 24 hours. This removes the soluble elastomeric phase and
leaves the crystalline polyolefln phase. After drying, the polyolefin phase
; was fractured under liquid nitrogen. The fracture surface was then coated
with a thin layer of carbon and gold by vacuum deposition and examined with a
scanning electron microscope. The nature of the polyolefin phase was clearly
distinguishable by this method and the distance be-tween phase boundries was
found to be less than about 1 micron.
~ r .. _~
f~3~
The preferred me-thod of blending the compositions of the instant
invention is to fixst prepare a masterbatch of elastomer and filler. This
is done by blending the elastomer and filler in a Banbury Mixer. This mas-ter-
batch can then be continuous],y blended with the crystalline polyolefin by
feeding both in a continuous mixer such as an extruder. A predetermined
amount of masterbatch can also be blended with a predetermined amoun-t of cryst-
alline polyolefin in a Banbury Mixer. It is also within the scope of the
present invention that a predetermined amoun-t of filler and elastomer be
initially blended in a Banbury and subsequently a predetermined amount of
crystalline polyolefin be introduced into said Banbury and blended wi-th -the
elastomer/black blend. The Banbury blending herein is performed for a period
of abou-t 2 to about 15 minutes at a ternperature of about 40 to about 220 C.
When a hydrocarbon oil is used, it is preferred that said oil be added -to the
elastomer or elastomer/black masterbatch prior to subsequent blending with the
crystalline polyolefin.
This invention and its advantages will be better understood by
reference to the following examples.
EXAMPLE 1
Four samples were prepared, each using a different carbon blac]c.
Each sample was compri,sed of 60 parts by weight of EPDM having a Mooney vis-
cosity of 40 at 100 C and a viscosity of 3.5 x 10 poise at 100 sec and
200 C as measured by capillary rheometry and containing about 5 wt. % ENB;
40 parts by weight of polypropylene; 45 parts by weight of carbon black; and
0.'3 parts of calcium stearate. In each of the four examples, the carbon
black and EPDM were first mixed in a Banbury Mixer for 3 minutes under cool
conditions (25-30 C star-ting temperature; 110-121 C dump -temperature). Poly-
propylene was added to this masterbatch in a second 3 minute mix under hot
conditions ~150-160 C starting temperature, 188-204 C dump temperature~. The
-- 10 --
,,,
~g3~7
samples were tested and the results are illus-trated i~ Table I below.
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N O
:~ ~ t')
L.l ~1 -- -- ~n
'l: IntJ~ t~) t~ N N
D . ~~D Ln O t~ Ln
D N ~ ~I t~ t~) t~ N r--l tJ~ ~1 ~1 ~ -- 'n
t,n n
U~ O r~
a ~ N -- ~
Zt~ ~ o ~ ~n
L'3 ~ O N t~) t'~ t~
m . ~) o ID m N t~' ~ I` ~' O ~ ~r N t
a ~3
~4 ~3
L~3 e~ L~ 'n
L~ ~tJ~ ~ O
O ~~3 N ~1 ~
L3 N I ~C -- -- I` -IJ
L3 3~ L~ t t~l N ~ ~ 0
1-1 ~3 ' (~ ~1' tJ~ ~ N t't L~ 1-- ~ tS~ tl) t,'O N N ~ ~1
~ ~: ~D ~1 ~1 D ~ t~) ~ t~) N N ~I t~ r-i ~1 ~1 -- t~l ~i LV
H ~ 3 L3 td
L3 ~0 0
~3 ~ ~Z ~_ :~
Z ~ 'n Ln a
O OL4 N t') L3
U ~ ~ N ~1 ~
~4 ~ In In t`~ tl~ '
O tl~ . . . ~ In ID O ~D
Z . n o o In c~ ~g co ~ o m o . . r-l. co . u~
q Hr~ r-l r-l r-l r-l t~) ~r t~- ~ t~7 r-l r~) r-l L~ r.~) ~ t~r) r-l (V
Q
O ~ S~
H ~
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L~ t~
O I O
E~ rl O O
~ ~ X ~ o
14 ~1 rl
L~3 Lll U~r~J r~
p~ D IIV LV
u) td td N
r~ tJ rl
u~ tdO m ,C
t~ y ~-- O
O h r~) rli ~ ttJ
Z IV ~ ,S3 Z ^ ~ ~0 IV 1:: tV r~
LJ O EV O ~} 13a ~ ~ ~ rl m ~ol r-l O
~: Pl ~1 I P' ~ r:n ~ P~ r~
LV rr E-l Ln ~ r-l t~
Ei ~ :>~ ~ ~ rn O ~ LV ~ ~ rd ~V t~ td LV ~ rl
td ~ V ~ E ~ ~ r~ ~ r~ 1 a
~V t) R ~ 1~1 O I I ~ ~ O X u) r-l LV U~
Ql td ~ m ,5 m ~ r~l Ln (V ~: ~3 rn C O td
~C r~ rd L`4 td ~V r-l rv tl) O rlJ
L3 m m m u~ O~o ~ m L~ ~
O O
rl N
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, " ,1, , , . , ,' ,. '-, ',
. ' . . ' ' ' .
. - . ~ , ,' - ' .
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The surface areas associa-ted with the blacks of Table I are:
GPF 28.3 m /g
HAF 6~.1
HAF-HA 65.7
HAF-LS 75.2
It is clear from Table I that the mechanical properties of the
resulting thermoplastic blends are improved when blacks having relatively
high rei.nforcing capacity (~Einer particle si~e) are i.ncorporated into said
blends. I'his is evident by comparing such properties as % bound rubber,
% elonga-tion, tensile product, and heat distortion of the resul-ting thermo~
plastic. Table I also illustrates the fact that spiral flow is maximized
by the use of an HAF-LS black.
- EXA~PLE 2
Four additional samples were prepared according to Example 1 except
that all ingredients were blended toyether in one operation in a Banbury
as opposed to the black~being Eirst blended with the EPDM. Table II illus-
trates that ~there are some disadvantages of blending all ingredients together
in one operation. These disadvantages axe believed to result from -the
poprer disperslon of black in thi~ kind of mix.
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- 13 -
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.:
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a~ r
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~r ~ r ~o N ~0 ro CO O r ~r o o N ~ O;)
f:l~ ' ~ . ~ ~ ~ ~ ~)(~ . ~O . O .
~ r . I o;) ~ ul ~I N r ~ o
N ~ ~1
~r rN~
N r-l
~ O '~ O ~
Z ~ I~ ~ r ~ ~ r~ ~ o
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a:
G
~ ~ r-ô
~ ~ N N ~
1:4.4 ~O U) CO 1` ~ N
O XN f~ 0 ~0 f'l O O C~ Lf) (~) . If)
~ ~ r- ~ O ~ N r~
~ ~ N --
H E-l
~ ~ ~ ~i~
. ~~ ~ N ~
m z ~ ~
E~O O ~ r ~ ~o r r co o~ o o In . ~
~i~ ~I t~ ~ r~ l O ~
~ HZ ~^ ~ .
~ Q I N ~
O ~ ~1 0 0
g ~ ~ ~ tn tno
O (11 ~ (~1 N
u o ~ ~ ~ R '`~
~1 , ~ U S~ ~ ` ~
3 ~ 3 ~ Q a~ o ~ ~ o l~
O O O ~ O
a~FLI u~ U ,1 ~ U
al uR R ~1 o rd ~ o X
L~ m m m ~n O~ m
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-- 19 --
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EXAMPLE 3
r~O elastomeric thermoplastic samples were prepared, one with a
hydrocarboll oil incorpora-ted there;n and one without. Both samples contained
30 parts of polypropylene having a melt flow of about 12 g/10 min. (as
measured by the procedure set forth in ASTM D 1238). The sample without
oil con-tained 70 parts of EPDM having an M of abou-t 35,000 and a viscosity
of abou-t 3.5 x 10 poise at 100 sec and 200 C. The sample with oil contain-
ed 70 parts of an equal amount by weight of hydrocarbon oil and EPDM wherein
said oil containing EPDM and an M of about 140,000 and a viscosity of about
10 3.6 x ]0 poise at 100 sec and 200 C. The blend containing oil had a
viscosity of about 1.6 x 10 poise at 100 sec and 200 C whereas the blend
containing no oil had a viscosity of about 4.2 x 10 poise at 100 sec and
200C.
This example illustrates that while the initial viscosities of -the
elastomeric phase were nearly identical, when blended with polypropylene,
the viscosity of the oil containing blend was significantly lower. Therefore,
the thermoplastic sample containing oil is more easily processed than that
containing no oil.
All M measurements were performed by membrane osmometry and all
20 viscosity measurements were performed on an Instron* Capillary Viscome-ter.
EX~MPLE 4
A composition was prepared by bolending in a Banbury for 10 minutes
the following: (a) 70 parts of an EPDM having an M of about 140,000 and
consisting of 68 wt. % of ethylene, and 5.1 wt. ~ of ENB; and (b) 30 parts of
a polypropylene having a melt flow of abou-t 5 g/10 min. On completion of
the blending, the blend was extremely difficult to mold in view of its high
viscosity. The blended material contained large lumps of unmixed EPDM and
* Trade Mark
,
~ - 15 -
' -' ' " '
.
3r~
was not useful as an elas-tomeric -thermoplastic. This example demonsta-tes the
fact that without the use of a hydrocarbon process oil lligh molecular weight
EPDM's are not useful for preparing e]as-tomeric thermoplastic blends.
EXAMPLE 5
.____
A composition was prepared according to Example 4 except tha-t 75 php
(per 100 parts of EPDM) Flexon* 876 (a hydrocarbon process oil) was first
blended with the EPDM before further blending with polypropylene on a hot
Banbury (150-160 C starting temperature, 188-204 C dump temperature) for
3 minutes.
The properties of the resul-ting thermoplastic are shown in Table III
below.
TABLE III
Spiral Flow, cm 3].2
~ardness (D), max/10 sec 32/24
Bend ~ecovery, 30 sec. 19.0
5 min. 16.0
Flexural Modulus, psi x 10 16.0
Tensile strength, psi 1185
% Elongation 415
Tensile Product x 10 Q92
T'nis example illustrates the need for a hydrocarbon process oil in
the preparation of an elastomeric therrnoplastic containing a high molecular
weight EPDM.
EXAMPI,E 6
Elastomeric thermoplastic compositions were prepared using the
ingredients set forth in Table IV. The EPDM and filler were first blended
in a Banbury under cool conditions as in Example 1. Polypropylene was added
* Trade Mark
- 16 -
,
~3~
with the resulting masterbatch for an additional 3 minutes under hot mixing
conditions, as in Example 1. The EPDM used in these experiments had an M
of 140,000 as measured by membrane osmometry, an ethylene content of 68 wt.%,
an ENB content of 5.1 wt. 96, and 75 parts of Flexon 876 (a hydrocarbon
process oil) per 100 parts of elastomers. The polypropylene had a melt
flow rate of 5 g/10 min. at 230 C and 2160g.
TABLE IV
(control)
Experiment 1 2 3 4
EP~M, pts 70 70 70 - 70
Polypropylene, pts 30 30 30 30
Atomite (1), pts 40 100
Suprex Clay (2), pts 100
Sunpar 2280 (3), pts20
Banbury mix time (min.) 10 8 10 8
Shore D Hardness 30 45 50 32
Tensile Strength, psi 1350 1500 1500 1500
% Elongation 180 100 200 4~0
~1) calcium carbonate, Clo microns particle size
(2) hydrated aluminum silicate,~ 2 micron par-ticle size
(3) Hydrocarbon process oil, paraffinic ASTM ~ 226 Type lOlB
The above table illustrates the use of nonblack fillers in the
instant invention.
EXAMPLE 7
These samples were prepared according to the procedure set forth in
Example 1, except the following ingredients were used: 60 par-ts by weight
of EP~M having an M of about 55,000 containing 5 wt. % ENB and an ethylene
content of 60 wt. %, 40 parts by weight, of polypropylene having an Mv of
c~bout 70,000; 45 parts by weight of black as indicated in Table V; and 40 php
based on 100 parts of EPDM of Sunpar* 2280 (a hydrocarbon process oil). The
resulting elastomeric thermoplastic samples were tested as before, and the
results are illustrated in Table V below.
* Trade Mark
- 17 -
3~7~t7
~n In
N
N ~r ~I N --' ~O
~1 ~) . \ ~ O
~O r-l r~ N ~ ~) I I I I ~\ CO ~) N `-- ~1
^ n
~1
~D ~-- Ln
r~ '1 N Ln .
' a~LO (~ r-i ~1 LnO cr~ I` O . C~ ~ (~ . Ln
Ln ~ ~ ~ ~ r~ N N ~I r--l ~1 ~ N N _ ~I N
~O
~ . N C)
~ ~ i- ~-- ~r u,
m ~1 LO ~ Ln N ~-- Ln
F~ ' C ) ~ ~ O ~ ~1 ~ N ~ ~ . ~) ~Sl N . ~)
~ n ~ ~1 ~ N ~) N N N r-~ (~ CO N ~ -- r-l 1`'1
.
~0
~ a
(~ N
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r~
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XO ~ O O U~
a) X ~ , t~ o _
3 F~ 3 ~ 0 h O O O
P~ tn O ~ o tn ~ v 1`
L~ O ,1 0 U)
~I X :~ ~ 0 ~ 1 rl O rl a
t~ m ~ m ~ ~ Ln tY~ ,~ Ln x tn ~ o
X ~ 0 0 Q~ 0 ~J ~ a) o
m m tn ~o ~ m ~ E~ O~o
o O
r--l N
-- 18 --
~3~7;~7
The above table again illustra-tes the advantages of using a hydro~
carbon process oil in the instant invention. It is also evident from -the
above table that an ~IAF-LS black gives superior results over other conventional
blacks even when a hydrocarbon process oil is used.
EX~MPLE 8
Two elastomeric thermoplastic compositions were prepared Erom a
relatively low molecular weight EPDM. One composition contained a hydro-
carbon process oil (Sunpar 2280) the other did not. The compositions were
prepared in a Banbury according -to the preferred procedure in which the black
and optional oil are first blended with the EPDM before further blending with
polypropylene.
TABI.E VI
Experiment No. 1 2
(w/o oil)(with oil)
EPDM (1) pts 70 70
PP (2) pts 30 30
Atomite* (ground calcite)40 40
Sunpar 2280 20
Tensile strength, psi 1495 1040
% Elongation 185 510
Flow in spiral mold, cm 14 23
(1) M = 45,000 (membrane osmometry), ethylene conten-t = 67 wt. % and
ENB content = 4.2 wt. %.
(2) Polypropylene llaviny a melt flow of 5 g/10 min. at 230 C and 2160 g.
It is evident from the above experiment that a relatively low mole-
cular weight EPDM is suitable for use in the elas-tomeric thermoplas-tics of
the instan-t invention.
EXAMPLE 9
Polypropylene (5~ n-heptane soluble, M = 70,000) was blended with
(aj an EPDM having an M of about 190,000, an ethylene con-tent of about 60 wt.
% and an ENB content of about 5 wt. % and (b~ Sunpar 2280. The weight ratios
* Trade Mark.
3~7~
oE the ingredients were 36.9/45.:l/18.0 respectively. Blending was carriecd
out in a sanbury mixer for 6 minutes such that the -temperature of -the blend
was in excess of 170 C at the end of the blending cycle.
The sample was injection molded at 200 C and -the following
proper,ies obtained:
Shore D ~lardness 37
Resiliency, Deg. 19
Ilexural Moclulus, psi23,000
Tensile Streng-th 1,390
~ EloncJation 275
The above data shows that -the blend oE this exampleis an e]astomeric
thermoplastic.
The sample was painted with a primer (Siebert Oxidermo*) and a top
coat of a flexible polyurethane enamel (Dureathene 100) in white and blue
color usiny standard techniques. The samples were -then tested for paint
adhesion, paint adhesion after water irnmersion, pain-t adhesion after salt
water immer$ion and thermal cycling. In no case was there adhesion failure.
In addition, weatherometer exposure showed no chanye in the paint surface
attributable to the substrate.
EXAMPLE 10
. _ .
The same inyredien-ts and procedure for mixiny as in Example 9 were
used excep-t the composition of the instant blend by weight is polypropylene
28.8, I,S-IIA~ carbon black 28.8, ethylene propylene terpolymer 30.7, process
oil 12.3. The following physical properties were obtained:
Shore D llardness 39
Resiliency, Deg 21
Flexural Modulus, psi21,500
Tensile Strenqth, psi1,930
Po Elonyation 520
These results show the sample to be a thermoplastic elastomer.
The sample was painted as in Example 1 and the same adhesion and weatherometer
results were obtained.
*Trade Mark
~ 20 -
~r
~3~7~t~
Electron scanning microphoto graphs show that the crystalline
polypropylene phase contains no carbon black.
EX~IPLE 1 1
Polypropylene is mixed in a Banbury as in Example 1 with 15 wt. %
process oil. ~fter injection molding, the surface of -the polypropylene had
a continuous film of oil and it was not possible to paint -the sample. This
exampl.e proves t:he need for a combination containing an amorphous ethylene
propylene elastomer in combination with the oil.
- 21 -
'~ .
.
