DE2934931A1 - HARDENABLE MIXTURE OF BUTADIEN / ACRYLNITRILE POLYMER AND AETHYLENE COPOLYMER - Google Patents

Description

DR.-ING. "WALTER ABITS DR. DIETER F. MORF DIPL.-PHYS. M. GRITSCHNEDER

Patent attorneys

²⁹ · ^Au <? ^ust

P.O. Box ββΟ 1Ο9. 8OOO Munich

: Chemlndua MOndsen Telex: (O) 0S39ea

AD 4946

E.I.DU PONT DE NEMOURS AND COMPANY Wilmington, Delaware 19898, V.St.A.

Curable mixture of butadiene / acrylonitrile polymer and ethylene copolymer

030011/0808

AD 4946 ^ 0-

The invention relates to curable blends and, more particularly, to improved curable blends of an acrylonitrile polymer and an ethylene copolymer.

Elastomers are often processed with emollients and plasticizers to make their applicability for various End uses can be extended. Lots of these emollients are liquids that can volatilize when exposed to high temperatures or which are extracted when the compound is exposed to solvents or oils. More durable, polymeric, liquid plasticizers are relatively expensive.

Research Disclosure No. 13816, October 1975 "describes the oil resistance of chlorosulfonated Polyethylene is significantly improved in blends in which a terpolymer (30 to 45 wt.%, Terpolymer, is based on the elastomer) made of ethylene / carbon monoxide / vinyl acetate is incorporated instead of ethylene / vinyl acetate copolymer. It is also stated that sealing means with excellent stickiness and rubberiness with mixtures of ethylene / carbon monoxide / vinyl acetate terpolymer with butyl rubber can be obtained.

In the ÜS-PS 3 780 140 terpolymers from ethylene / carbon monoxide / termonomer and mixtures of the same in an acceptable amount of at least one solid, organic Polymer described. Various termonomers are described, such as unsaturated mono- and dicarboxylic acids, Esters of such acids, vinyl esters of saturated carboxylic acids, vinyl alkyl ethers, acrylonitrile, etc. Solid, organic Polymers are described that preferably have polar properties so that one can work on a molecular scale Compatibility received. Such polymers can be: polyamides; cellulose derived polymers; Vinyl halo-

- 2 030011/0808

AD 4946 ~ ¥

low polymers; α-olefin derived polymers such as Polyethylene, polypropylene, chlorosulfonated polyethylene; Ethylene-vinyl ester copolymers; Polymers of styrene; Polymers of acrylonitrile and copolymers of at least 4O? 6 acrylonitrile and other ethylenically unsaturated comonomers, such as vinyl acetate, vinyl chloride, and isobutylene; Acrylic compounds, Polyester; Polyurethanes, polycarbonates} phenolic compounds; Polysulfones; Epoxy resins; chlorinated Polyether; Alkyd resins; Acetal resins; ABS resins; Silicone resins; Tars; Waxes; etc..

In US Pat. No. 2,495,286, copolymers of ethylene and carbon monoxide with one or more additional polymerizable organic compounds such as other olefins, butadienes, vinyl and vinylidene compounds, vinyl esters, Styrene, acrylic and methacrylic acids and their esters, etc. are described.

In US-PS 3,873,494 curable mixtures and vulcanizates are described from 100 parts of an ethylene / alkyl acrylate or alkyl methacrylate copolymers or an ethylene / alkyl acrylate or methacrylate terpolymer, the teraonomer can be, among others, carbon monoxide, with 1 to 30 parts of a Butadiene / acrylonitrile polymers. The termonomer is present in an amount not exceeding about 10% by weight, based on the terpolymer, available.

The invention is a curable mixture of (a) 100 parts of a butadiene / acrylonitrile polymer containing about 20 to 50 wt.% Acrylonitrile, and (b) about 3 to 100 parts of ethylene copolymers selected from the group consisting of ethylene / carbon monoxide / X and ethylene / sulfur dioxide / X copolymers, where the comonomer X can be: (I) a vinyl ester of an alkanoic acid or alkanecarboxylic acid, the acid containing 1 to 18 carbon atoms, (II) an alkyl «

030011/0808

AD 4946 - 5-

acrylate or methacrylate, v / orin the alkyl group from 1 to 18 carbon atoms contains, (III) alkyl vinyl ether, the alkyl group containing 1 to 4 carbon atoms, (IV) acrylonitrile or methacrylonitrile or mixture or combinations of the above comonomers, the ethylene copolymer about 3 to 25 wt.% carbon monoxide or sulfur dioxide, about 10 to Contains 65% by weight of comonomer X and about 30 to 75% by weight of ethylene.

The invention also relates to masses or compositions which contain the curable mixtures described above with a peroxide or sulfur curing system.

The invention furthermore relates to vulcanized products which, by heating the mixture of the above-listed, curable mixtures and the peroxide or sulfur curing systems have been obtained.

It has been found that the modification of curable mixtures of butadiene / acrylonitrile polymers with an ethylene / carbon monoxide or sulfur dioxide copolymer which contains at least one additional, copolymerizable softening comonomer, such as a vinyl ester, alkyl acrylate or methacrylate, acrylonitrile, etc., contains vulcanizates with improved processability, reduced cost and, compared to modification with low molecular weight modifiers, better performance in the prepared compounds, better oil resistance and aging resistance.

As a result of the specified, improved properties, these modified vulcanizates can be used in extruded forms, such as pipes or hoses, seals and coatings or sheaths or sheaths for electrical cables, in composite structures or composite structures, such as with

- 4-030011/0808

AD 4946 - b '

Fabrics or textiles reinforced hoses, tapes and coated foils or plates in shoe sole joints including cellular materials, and in the case of various other shaped articles, such as waterproofing and O-rings can be used.

The solid butadiene / acrylonitrile polymer (nitrile rubber) which is the main component of the blends of the invention is a well known material. It can be prepared, for example, by free radical-initiated copolymerization of butadiene and acrylonitrile, either in solution or in emulsion, by processes known per se. The molecular weight of the material should be such that it has Mooney viscosities (ML-4, 100 ^° C.) of about 20 to 120. The suitable butadiene / acrylonitrile polymers should not be restricted to bipolymers. Terpolymers such as carboxylated butadiene / acrylonitrile polymers can also be used. These can be achieved by copolymerizing butadiene, aprylnitrile and a polymerizable carboxylic acid, ζ. Β. Acrylic acid or methacrylic acid. For practical purposes, suitable butadiene / acrylonitrile polymers are commercially available including those grades premixed with polyvinyl chloride resin.

The proportion of acrylonitrile in the polymer is generally about 20 to 50% by weight; the preferred proportion is about 25 to 41% by weight, with such polymers an optimal balance of the elastomeric properties and the durability show towards fluids.

The ethylene copolymer modifier of the present invention is an ethylene-carbon monoxide or -Schwefeldioxid-Ciopolymer that contains at least one further copolymerizable soft machercomonomer, such as (a) Vinylester of alkanoic acid, wherein the acid is 1 to 18 carbon atoms includes, for example,

030011/0808

Vinyl formate, vinyl acetate and vinyl stearate; (b) alkyl acrylates or methacrylates, wherein the alkyl group contains 1 to 18 carbon atoms, e.g. B. methyl acrylate, methyl methacrylate, Ethyl acrylate, ethyl methacrylate, ethylhexyl acrylate and stearyl acrylate (c) alkyl vinyl ether, the Alkyl group contains 1 to 4 carbon atoms, e.g. B. methyl vinyl ether; (d) acrylonitrile or methacrylonitrile or mixtures of the above comonomers.

The carbon monoxide or sulfur dioxide component of the invention Ethylene copolymers should be present in an amount of about 3 to 25 weight percent, preferably about 6 to 15 weight percent be.

The additional. , The copolymerizable plasticizer component of the ethylene copolymer of the present invention can be used in an amount from about 10 to 65% by weight, preferably about 20 to 35% by weight, to be available.

The amount of ethylene in the copolymer should be about 30 to 75 wt. #, Preferably about 50 to 70 Gev '% _t be.

In these copolymers, the copolymerized carbon monoxide or the sulfur dioxide imparts a high level to the polymer Degree of polarity without unduly reducing the ethylene content of the polymer. For example, 1 weight gives 96 copolymerized carbon monoxide has a polarity equivalent to the polymer from 3 to 5 wt. # of the exemplary one Comonomers X, e.g. vinyl acetate, methyl acrylate or 2-ethylhexyl acrylate. This property is different Reasons are important: (a) with a relatively high ethylene content, such polymers have sufficient polarity, see above that they are compatible with the nitrile rubber, (b) at a given polarity value, copolymers are copolymerized Contain CO or SO, less sticky than those,

- 6 030011/0808

AD 4946 "* '

which only contain ethylene comonomer X, and they can therefore be processed more easily because they are on the surfaces less sticking to the processing device; (c) in addition to the compatibility considerations, the Polarity is required in order to ensure the resistance of the nitrile rubber mixtures and vulcanizates to fluids such as fuels and oil to surrender.

The amount of ethylene copolymer in the blends of the invention is about 3 to 100 parts, preferably about 5 to 50 parts, per 100 parts of butadiene / acrylonitrile polymer.

The butadiene / acrylonitrile polymer including such qualities, which are modified with polyvinyl chloride resin, and the ethylene copolymer can be uniform with any the usual mixing devices, such as with a roller mill, an extruder, a Banbury mixer or with other internal mixing devices, be mixed with which the mixing of the materials without excessive heating of the mixture is possible. Other compounding ingredients that are well known and used in elastomeric compounds can also be added. Solid additives including reinforcing agents, fillers, pigments and resins are examples thereof. Examples of such materials are also carbon black, silicon dioxide, calcium carbonate, Titanium dioxide, hydrocarbon resins and phenolic resins. Liquid additives include processing oils, plasticizers, both monomeric and polymeric, and liquid nitrile rubber.

Other materials, such as stabilizers, antioxidants, anti-ozone agents, lubricants, stripping agents and degreasing agents and additives, through which certain properties the compound can be added in small proportions.

- 7-030011/0808

AD 4946 - 3 -

The mixtures are vulcanized according to known methods Procedure. The chemical vulcanizing agents can be in the Banbury mixer, the roller mill or another Mixing device can be added under such conditions that precuring of the compound is avoided. Although a co-cure of the butadiene / acrylonitrile polymer and the ethylene / carbon monoxide or sulfur dioxide copolymer component gives superior properties to this composition, it is not an essential part of the present Invention.

Chemical agents normally used for vulcanization of butadiene / acrylonitrile polymers used are satisfactory for curing the mixtures according to the invention.

The acceleration of vulcanization and a variety of curing systems for nitrile rubber are discussed in the chapters 5 and 6, respectively, of "Vulcanization of Elastomers" edited by G. Alliger and I.J.Sjothun (Reinhold Publishing Corp.), and in company literature. Company literature by B.F.Goodrich Chemical Company in this area includes: Manual HM-7, revised (6011-6710-LP), "Accelerators, Pigments, and Plasticizers for Hycar Nitrile Rubber "; Manual HM-9» revised (6906-SPM),; Vifcanizing Nitrile Rubber ». On the Disclosure of the above publications is expressly incorporated by reference.

Typical curing agents are peroxides and sulfur / accelerator systems. Organic accelerators can and are generally used together with the vulcanizing agents and are dispersed within the vulcanizable mixture in order to shorten vulcanization times and to decrease cure times. Furthermore, the proportion of vulcanizing agent can be reduced. With the present

- 8 030011/0808

AD 4946 __ / iff .

In the invention, any conventional sliming agents can be used will. Examples of accelerators that can be used alone or in a mixture include thiazoles, mercapto accelerators, like mercaptobenzothiazole, and sulfenamide accelerators, e.g. derivatives of mercaptobenzothiazole; Guanidine accelerators, e.g. diphenylguanidine (DPG) and di-tolylguanidine (DOTG); Thiurams such as thiuram monosulfides and thiuram disulfides; and dithiocarbamates. The amount of accelerator which is used can vary over a wide range and the amount depends on the particular chemical composition, the accelerator and the intended use of the elastomer. In general the amount of accelerator that is used is about 0.2 to 4 parts, preferably 0.5 to 2 parts, per 100 parts Nitrile rubber. Furthermore, accelerator activator systems containing zinc oxide and stearic acid can be used.

The final composition is shaped and cured by methods known per se, for example by extrusion, injection molding, compression molding, transfer molding or transfer molding or by processing on the calender into sheets, films or plates or on a substrate. Steam, a hot fluid or microwave heating can be used for curing, generally at temperatures of about 100 to 210 ^° C. for about 0.5 to 120 minutes.

The invention thus relates to curable mixtures of butadiene / acrylonitrile polymers, which by modification with ethylene / carbon monoxide or sulfur dioxide copolymers which contain an additional, copolymerizable plasticizer comonomer, such as vinyl esters, alkyl acrylates and methacrylates, alkyl vinyl ethers, acrylonitrile, methacrylonitrile, etc. ., have been received. The modification with the ethylene copolymers gives an improved

- 9 -03001 1/0808

AD 4946-4 ) ~

workability, discounted cost and, compared with modification with low molecular weight modifiers, better behavior, better Oil resistance and aging resistance.

The following examples illustrate the invention. Unless otherwise stated, all are parts and percentages expressed by weight.

Examples 1 to 2

In these examples the sulfur and peroxide cure of E / VA / CO nitrile rubber vulcanizates is used of carbon black as reinforcement, different nitrile rubbers and different ethylene / vinyl acetate / carbon monoxide terpolymers explained. The compositions and properties are summarized in Table I.

These compounds are on a 7.62 χ 17.78 cm (3 ⁿ x 7 ") mill mixed, removed in the form of films or plates, and press-cured at 154 ⁰ C for 30 min. The tensile properties on an Instron Tensile Tester ( Test device).

A comparative composition which does not contain a modifier is described below as Comparative Example C1 listed.

Compared with the unmodified nitrile rubber compound of the following Example C1, show the compositions these examples show improved behavior on the mill, i.e. the formation of a "smoother bank" (smoother bank) in the roller mill and easier incorporation of the soot.

- 10 -

COPY 030011/0808

AD 4946 - Al-

As is well known, the behavior of the compound on a roller mill is an important processing parameter. The formation and maintenance of a smooth bench and continuous belt facilitates the incorporation of the other constituents of the mass. When the ethylene copolymers according to the invention are added to nitrile rubber, that is wedded, the band is retained. In contrast, if known, liquid plasticizers are added, like polyester used in Comparative Example C3, the tape is often broken until the liquid is absorbed.

Tabel I. Example 1 Example 2 Example 3 E / X / CO nitrile rubber vulcanizates 100 ... ... (L)
Components. phr ^v ' ... 100 100 "Hycar" 1041 ^ ¹ ^ ... "Hycar" 1042 ^ "Hycar" 1043 ^ ³ ^ 30th «•« MM » ... E / 23.5% VA / 11% CO Copolymer, 35 MI 30th ... E / 29% VA / 10% CO Copolymer, 35 MI ... --- 30th e / 25.5% MA / 8.6% CO 5 5 5 Copolymer, 6 MI 1.5 ... ... zinc oxide 60 60 60 sulfur 1.0 1.0 1.5 SRF soot 1.5 Stearic acid 4.0 4.0 Mercaptobenzothiazyl sulfide Dicumyl peroxide / CaCO ^ (40/60) 13.7 13.6 15.0 Drawings 390 470 430 Tensile strength, MPa 3.6 1.9 2.3 Strain, % 76 61 65 Module about 100% elongation, MPa Shore Α hardness, points

- 11-030011/0808

AD 4946 ^ $ 4.

( 1 )

^κ ' butadiene / acrylonitrile polymer (nitrile rubber),

available from BFGoodrich Company, containing 41 % acrylonitrile (AN) and having a Mooney viscosity of 80;

33% AN, 80 Mooney;
29% AN, 80 Mooney;
'' Parts per 100 parts rubber ingredient.

Example 3

In this example, the ethylene copolymer used is E / 25 »5% methyl acrylate / 8.6% CO, 6 MI, and" Hycar "1042, 33% acrylonitrile, 80 Mooney viscosity, is used as the nitrile rubber. The remaining ingredients are the same as in Example 2. The stearic acid content is increased from 1.0 phr to 1.5. Milling is done on a 6 "15" (15.24 by 31.10 cm) mill. The film or sheet samples are compression molded and cured at 154 ° C. for 30 minutes. The composition and properties are summarized in Table I. After aging in the air oven for 70 h at 121 ⁰ C be the tensile strength, elongation, modulus at 100% elongation and Shore A hardness of 17.0 MPa and 360% and 3.4 MPa or 69th

The comparative properties of the unmodified "Hycar" 1042 vulcanizate are in Comparative Example C1, Table I, listed.

As in Example 2, the modification with the polymer results in improved behavior on the mill Mass and softening of the vulcanizate.

Comparative Examples C1-C3 and Examples 4-5

These examples illustrate the properties of nitrile rubber compounds reinforced with carbon or carbon black

- 12 030011/0808

AD 4946 - ^

compared that included; (C1) no added plasticizer, (C2) an E / VA copolymer mixed with a monomeric one Phthalate plasticizer, (4) an E / VA / CO copolymer with the Phthalate plasticizer, (C3) a polymeric polyester plasticizer, and (5) an E / VA / CO copolymer with polymeric plasticizer. These compounds are processed in the same manner as described in Example 3. The composition and the properties of the compounds are listed in Table II. The properties are according to the specified ASTM method determined. The values of the samples exposed to solvents are the "immediate harmful" Properties, i.e. that are determined when the sample is still saturated with solvent. The examples 4 and 5 are embodiments of the invention. example 4 is a preferred embodiment because it has good property and moderate cost. As well as the E / VA modified compound of Example C2 as well as the E / VA / CO modified compound of Example 4 gives superior low-temperature properties with the Blash-Berg hardness or stiffness and reduced temperature brittleness, compared to the other compounds in this series. Furthermore, the compound of Example 4 is better than that of Example C2 for resistance to oven aging and

what by a small

Change in percentage of properties is evident. The reduced volume swell after exposure to reference fuel ⁿ B ^M is noteworthy. The compound of Example 4 is cheaper than the compound of Example C3 while exhibiting the same or better overall properties. The compound of Example 5 gives a higher initial tensile strength than that of Example 4, but shows no improvement in the aging properties.

- 13 030011/0808

- --- 30th 15th 60 60 60 60 5 5 VJl VJi 1.5 1.5 1.5 1.5 VJl 5 VJI 5

AD 4946 '4S-

Table II

Comparison of nitrile rubber vulcanizates, the different
Contain plasticizers

Components, -phr examples

UT Cj? 4 ~ g? ^ L

"Hycar" 1042 100 100 100 100 100

E / 23.5% VA / 11% CO,

35 MI copolymer 15 15

E / 40% VA, 57 MI copolymer

"Santicizer" 711
"Santicizer" 429
SRF carbon black 60

Zinc oxide 5

Stearic acid 1,

Dicumyl peroxide / CaCo, (40/60) 5 Physical properties

original hardening
30 min approx. 155 ⁵ C

Tensile Strength (ASTM D-471)

MPa 19.0 14.0 14.3 17.2 16.9

Elongation,% 230 440 360 400 380

Module approx. 100% elongation, MPa 4.5 1.9 2.1 1.5 2.4

Shore Α hardness, points

(ASTM D-2240) 70 57 61 50 60

permanent deformation, %

(ASTM D-395, B) 23 27 39 23 35

Mooney Scorch (ASTM D-1646) 121 ^° C

MV, units 42

Δ5, min 18

A 35, min 45

Clash Mountain (ASTM D-1043)

T _f 10,000, ° C -23

Embrittlement point

(ASTM D-746), -42 ° C

- 14 -

17th
30th 22nd
70 16
30th 23
30th -34 -34 -33 -30 -45 -45 -41 -40

030011/0808

AD 4946

Table II (continued)

Physical Properties

Aging

(37

in an air oven, 70 h, approx. 121 ⁰ C (ASTM D-573)

Tensile strength, MPa elongation, %

Module about 100% elongation, MPa Shore Α hardness, points

Reference fuel ⁿ B "

70 h, approx. Room temperature (ASTM D-471)

Tensile strength, MPa elongation, %

Module approx. 10050 elongation, IiPa Shore Α hardness, points

Volume swelling, %

Methanol . 70 h, about 64 ° C CASTM D-471)

Tensile strength, MPa elongation, %

Module, about 100% elongation, MPa

Shore Α hardness, points volume swelling, %

C1

Examples

C2

C3

20.3
(+6) 15.2
(+8) 16.3
(+14) 16.1
(-6) 16.1
(-5) 2.6
(+6) 210 200
(-13) 28o
(-22) 300 240
(-25) (- 37) 43
mn ? &> 6.4
(+43) ? 4) 3.5
(+64) 2.5 4.3
(+64) (+ 77) +38 f-7)
) (Pte) 76
+6)
(Pte) 67
7 + 10)
(Pte) 65
(+4)
(Pte) 51 68
i + 1) (+8)
(Pte) (Pte) 9.6 9.2
(-44) (- 45) +14 9.2
(-52) 6.3
(-55) 8.8
(-38) 8.8 8.1
(-49) (- 52) 260 150
(-35) 200
(-54) 220
(-39) 220 190
(-45) (- 50) 4.3
(-5) 1.9
(+4) ² ! ¹
(-3) ¹ (6f 44
-6)
(Pte 58
i-12)
(Pte) 38
(-19)
(Pte) 47
(-14)
(Pte) 37
(-13
(Pte +7 +30 +46 +28 +32 10.2
(-46) 8.9
(-36) (-37) 170 290 200 3.6
(-18) 1.8
(-4) (+39) 63
(Pte) 45
f-12)
(Pte) 48
(-13)
(Pte) +19 +14 +12

- 15 -

030011/0808

AD 4946 - ^,

Alkyl phthalate plasticizers, the alkyl group contains 7 Ms 11 carbon atoms and about 30% branching, available from Monsanto Company;

(2)

^v 'polymeric polyester plasticizer with a medium high molecular weight, available from Monsanto Company;

^ 'Change from the original value is in brackets listed. The change is expressed as a percentage unless otherwise stated.

Examples 6-7

In these examples nitrile rubber vulcanizates are described, those with different E / CO / softening comonomer copolymers are modified. Example 6 is an E / 21% ethylhexyl acrylate / 7.7 / 0 carbon monoxide copolymer with a melt index of 70 is used. Example 7 uses an E / 20% methyl vinyl ether / 11% carbon monoxide polymer with a melt index of 40 is used. As can be seen from the tensile values in Table III, these have with Sulfur cured vulcanizates have very good properties.

Table III Example 6 Example 7 E / CO / X nitrile rubber vulcanizates 100 100 Constituents, phr 15th - "Hycar" 1042 15th E / 21% BRAZIL CO, 70 MI 15th 15th E / 20% MV / 11% CO, 40 MI 60 60 "Santicizer" 711 5 5 SRF soot 1 1 zinc oxide 1.5 1.5 Stearic acid 1.5 1.5 sulfur 2 2 Mercaptobenzothiazyl sulfide Di-o-tolylguanidine

- 16 -

030011/0808

AD 4946 "4S -

Table III (continued)

Physical Properties Example 6 Example 7 Samples, hardened for 30 min at approx. 155 ° C Tensile strength, MPa 16.8 14.6 Elongation, % 500 440 Module approx. 10090 elongation, MPa 2.9 2.6 Shore Α hardness, points 64 62 Example 8

This example illustrates the use of an ethylene copolymer to modify a premelted blend of 70% nitrile rubber and 30% "Geon" polyvinyl chloride resin, commercially available under the trademark "Hycar" 1203 from BFGoodrich Chemical Company. A mill batch is produced which contains in parts by weight: 100 parts of "Hycar"1203; 20 parts of an E / 23.5 % VA / 1150 CO copolymer with a melt index of 35; 20 parts of "Santicizer" 711 phthalate plasticizer; 60 Parts of SRF carbon black; 3.5 parts of zinc oxide; 1 part of stearic acid; and 4 parts of dicumyl peroxide / calcium carbonate carrier (40% peroxide / 60% calcium carbonate, available as "Luperox" 500-4OC from Lucidol Division of Pennwalt Corporation) Hardening at 155 ° C. for 30 minutes is as follows: tensile strength 14.5 IiPa; elongation 310%; modulus at 100% elongation 5.1 MPa; Shore A hardness 73; Clash-Berg T _f 10,000, -20 ⁰ C .

Example 9

This example uses 15 parts by weight of each E / 24% MA / 9.7% CO, 6 MI polymer, "Santicizer" 711 phthalate plasticizer and "Nevex" 100 hydrocarbon resin (sold by Neville Chemical Company), 100 parts "Hycar" 1042 nitrile rubber, 60 parts SRF carbon black, 5 parts Zinc oxide, 1.5 parts of stearic acid and 4 parts of Dicuraylper-

- 17 030011/0808

AD 4946 ^? 5-

oxide / calcium carbonate carrier (40% peroxide / 60% calcium carbonate). The warm mass is soft and sticky before vulcanization. It is known that unmodified nitrile rubber compounds are relatively stiff and board-like. If you use a combination of E / X / CO or S02 ~ polymer with the phthalate plasticizer and even more with these two modifiers plus hydrocarbon resin, the nitrile rubber compound becomes more flexible. This property allows the joint to better conform to surfaces and this is very helpful when building articles that contain multiple layers, such as fabric reinforced tubing. Tensile strength of 10.3 MPa; after press curing at 155 ⁰ C for 30 min to give the following vulcanizate Elongation 710%; Modulus at 100% elongation 1.2 MPa; Shore A hardness 51; Clash Mountain T _f 10,000, -30 ° C; and embrittlement temperature -34 ° C. After air-oven aging at 121 ⁰ C during 70 hours, the tensile strength be 13.8 MPa and 500% and 1.9 MPa, and the compound exhibits an increase in hardness by 7 points to a hardness of 58th

Examples 10-11

Two other nitrile rubber compounds are prepared in an identical manner as described in Example 6, with the exception that an E / 29% VA / 9% SO ₂ copolymer with an MI of 60 (Example 10) or an E / 11% AN / 12% CO copolymer with an MI of 0.2 (Example 11) is used. The original vulcanizate properties and those after oven aging are listed in Table IV.

- 18 -

030011/0808

AD 4946

Table IV • Example 10 Example 11 Properties of an E / CO or SOg / X nitrile rubber vulcanizate 14.6 14.4 Originally 390 570 Tensile strength, MPa 3.0 2.0 Elongation, % 67 63 Modulus at 100-6 elongation, MPa Shore Α hardness, points 16.4 17.3 Aging at 121 ^° C. for 70 h 340 360 Tensile strength, MPa 4.3 3.9 Elongation, % 71 72 Modulus at 100% elongation, MPa Shore Α hardness, points Comparative Example C4 and Example 12

In these examples, the influence of E / 23.5 # VA / 11 # CO copolymer MI 35, as a hardness reduction modifier for nitrile rubber, compared with cashbene oil-modified phenolic resin containing 8% hexamethylenetetramine and sold by Hooker Chemical Co. as "Durez" 12687 resin is available is modified. In Comparative Example C4, a compound is prepared by grinding 100 parts of nitrile rubber (33 # nitrile, 80 Mooney), 60 parts of phenolic resin, 5 parts of zinc oxide, 1.5 parts of stearic acid, 1.5 parts of sulfur and 1.5 parts of mercaptobenzothiazyl sulfide. Example 12 additionally contains 30 parts of the above E / VA / CO copolymer. Panels are press cured at 155 ° C for 30 minutes. Table V shows the tensile and hardness properties of the vulcanizates after curing and aging at 121 ^° C. for 70 h.

- 19 -

030011/0808

AD 4946 &

Table V Nitrile rubber-phenolic vulcanizates

Original properties Ex. C4 Ex. 12

Tensile Strength, MPa 19.0 15.5

Elongation,% 200 230

Module at 100% load, MPa 14.8 7 »5

Shore Α hardness, points 95 84

Aging at 121 ^° C. for 70 h

Tensile Strength, MPa 21.9 12.3

Elongation,% 75 100

Module at 100% load, MPa - 12.5

Shore Α hardness, points 97 86

The properties of the vulcanizate of Example 12 showed that the E / VA / CO- ^ polymer had the modulus and hardness of the original Vulcanizate considerably reduced. After aging in an air oven, the E / VA / CO modified Vulcanizate has an elongation of 100%, while the unmodified vulcanizate has an elongation of only 75%.

End of description.

- 20 -

030011/0808

Claims (3)

Claims 1. A curable mixture of ethylene terpolymer and Butadiene / acrylonitrile polymer, characterized in that the mixture contains: (a) 100 parts of a butadiene / acrylonitrile polymer, containing about 20 to 50 weight percent acrylonitrile, and (b) about 3 to 100 parts ethylene copolymer from the group of ethylene / carbon monoxide / X and ethylene / sulfur dioxide / X copolymers, in which the comonomer X is (I) a vinyl ester of an alkanecarboxylic acid, the acid containing from 1 to 18 carbon atoms; (II) for an alkyl acrylate or methacrylate, the alkyl group containing 1 to 18 carbon atoms; (III) for an alkyl vinyl ether, the alkyl group containing 1 to k carbon atoms; (IV) stands for acrylonitrile or methacrylonitrile or combinations of the above comonomers, and wherein the ethylene copolymer contains about 3 to 25% by weight carbon monoxide or sulfur dioxide, about 10 to 65% by weight comonomer X and about 30 to 75% by weight ethylene. 2. Composition, characterized in that it is the mixture of claim 1 and a peroxide or sulfur curing system contains. 3. Vulcanized product, characterized in that it has been obtained by heating the composition of claim 2 for about 0.5 to 120 minutes at about 100 to 210 ^° C. 030D11 / 0808