CA1093727A

CA1093727A - Paintable moldable elastomeric thermoplastics

Info

Publication number: CA1093727A
Application number: CA257,289A
Authority: CA
Inventors: Albert M. Gessler; Edward N. Kresge
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1975-08-13
Filing date: 1976-07-19
Publication date: 1981-01-13
Also published as: DE2636096A1; JPS5223148A; FR2320969B1; IT1065929B; BE845119A; GB1550207A; JPS5914065B2; DE2636096C2; FR2320969A1

Abstract

ABSTRACT OF THE DISCLOSURE
Unvulcanized elastomeric thermoplastic composition of a highly crystalline polyolefin, such as polypropylene, and a noncrystalline or semi-crystalline polyolefin, such as EPR or EPDM are found to have superior physical as properties well as better processing properties by blending with said composition:
(a) a plasicizer such as hydrocarbon oil; or (b) a carbon black with high reinforcing capacity and low aggregate structure such as an HAF-LS black; or (c) both the plasticizer of (a) and the black of (b). The composition are useful for molded and extruded articles such as injection molded automotive decorative and structural parts.

Description

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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

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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 .

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~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 ~ .

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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 _ ~ ., .. ~ ~ .

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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.

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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.

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 ,,, ~g3~7 samples were tested and the results are illus-trated i~ Table I below.

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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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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 -' -' ' " ' .

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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.

.____ 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 , ~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.

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.

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~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.

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.

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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.

. _ .
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.

'~ .

.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. 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 olefin and a C5-C14 nonconjugated diolefin;
(b) about 15 to 70 parts by weight of a C2 to C8 crystalline polyolefin; and (c) about 5 to 150 parts of hydrocarbon oil, per 100 parts of said elastomeric copolymer or terpolymer, selected from the group con-sisting of naphthenic and paraffinic oils.

2. The thermoplastic of claim 1, wherein about 5 to 100 parts of a hydrocarbon oil are present.

3. The thermoplastic of claim 2 wherein the higher alpha olefin is propylene.

4. The thermoplastic of claim 2 wherein the nonconjugated diolefin is 5-ethylidene-2-norbornene.

5. The thermoplastic of claim 3 wherein the nonconjugated diolefin is 5-ethylidene-2-norbornene.

6. The thermoplastic of claim 2 wherein the crystalline polyolefin is polypropylene.

7. The thermoplastic of claim 5 wherein the crystalline polyolefin is polypropylene.

8. An elastomeric thermoplastic comprised of:
(a) about 85 to about 30 parts by weight of an elastomeric co-polymer of ethylene and at least one C3 to C10 higher alpha olefin or an elastomeric terpolymer of ethylene, at least one other C3 to C10 higher alpha olefin and a C5 to C14 nonconjugated diolefin;
(b) about 15 to about 70 parts by weight of a C2 to a C8 crystalline polyolefin;
(c) about 5 to about 150 parts of a hydrocarbon oil, per 100 parts of co- and/or terpolymer, selected from the group consisting of naphthenic and paraffinic oil; and (d) about 10 to about 120 parts per 100 parts of said elastomeric copolymer or terpolymer of a carbon black having high reinforcing capacity and low aggregate structure.

9. The thermoplastic of claim 8 wherein the higher alpha olefin in both the co- and terpolymers is propylene.

10. The thermoplastic of claim 8 wherein the nonconjugated diolefin is 5-ethylidene-2-norbornene

11. The thermoplastic of claim 9 wherein the nonconjugated diolefin is 5-ethylidene-2-norbornene.

12. The thermoplastic of claim 8 wherein the crystalline polyolefin is polypropylene.

13. The thermoplastic of claim 11 wherein the crystalline polyolefin is polypropylene.

14. The thermoplastic of claim 8 wherein the number average molecular weight of the co- or terpolymer is about 120,000 to 160,000.

15. The thermoplastic of claim 2 wherein said thermoplastic consists of two continuous phases, an elastomeric phase and a resin phase, separated from each other by a mean distance of less than 1 micron.