WO2004106429A1

WO2004106429A1 - Rubber composition and crosslinked molding obtained therefrom

Info

Publication number: WO2004106429A1
Application number: PCT/JP2004/007500
Authority: WO
Inventors: Yoshiyuki Odagawa; Fumio Ikeda; Nobuyoshi Emori
Original assignee: Zeon Corporation
Priority date: 2003-05-30
Filing date: 2004-05-31
Publication date: 2004-12-09
Also published as: JPWO2004106429A1

Abstract

A rubber composition comprising a nitrile copolymer rubber (A), an ethylene/α-olefin copolymer rubber (B), and a graft copolymer (C), in which the graft copolymer (C) is one obtained by copolymerizing at least one monomer selected among α,ß-ethylenically unsaturated monomers and aromatic vinyl monomers with an ethylene/C4 or higher α-olefin copolymer, the total content of α,ß-ethylenically unsaturated monomer units and aromatic vinyl monomer units in the graft copolymer (C) is 10 to 60 wt.%, the amount of the graft copolymer (C) is 1 to 30 parts by weight per 100 parts by weight of the sum of the nitrile copolymer rubber (A) and the ethylene/α-olefin copolymer rubber (B), and the nitrile copolymer rubber (A) and the ethylene/α-olefin copolymer rubber (B) account for 50 to 80 wt.% and 20 to 50 wt.%, respectively, of the sum of the nitrile copolymer rubber (A) and the ethylene/α-olefin copolymer rubber (B).

Description

Specification

Rubber composition and crosslinked molded product thereof

Technical field

The present invention relates to a rubber composition which is excellent in ozone resistance, mechanical strength, and extensibility and hardly causes delamination, and is a material for a crosslinked molded product, and a crosslinked molded product thereof.

Background art

Conventionally, chloroprene rubber has been widely used as a rubber material having both oil resistance and ozone resistance. However, since chloroprene rubber contains chlorine and may cause environmental problems, alternative materials have been required.

[0003] As a substitute for chloroprene rubber, a rubber composition comprising nitrile. Conjugated copolymer rubber and an olefin elastomer has been studied. Even if only these two types of rubber are kneaded, they do not mix uniformly. As a result, the molded product obtained by crosslinking and molding this rubber composition has excellent ozone resistance, Inferior in bending fatigue, and delamination sometimes occurred at the interface between nitrile. Conjugated diene copolymer rubber and olefin elastomer during use. In order to improve the compatibility of the nitrile 'copolymer rubber and the olefinic elastomer, it is extremely difficult to uniformly disperse the It has been proposed to add a graft copolymer obtained by copolymerizing a mixture of styrene and a polar vinyl compound with one propylene-one diene copolymer (see, for example, JP-A-54-106554). . However, when this composition is subjected to cross-linking molding, a cross-linked molding having excellent aging resistance and oil resistance can be obtained, but the delamination has not been sufficiently suppressed.

Disclosure of the invention

[0004] In view of the background art described above, an object of the present invention is to provide a rubber composition that is excellent in ozone resistance, mechanical strength, and extensibility, and that is used as a material of a cross-linked molded article that is unlikely to cause delamination, and a bridge molding thereof To provide things.

The present inventors have conducted intensive studies to achieve the above object, and found that a polymer alloy of nitrile copolymer rubber and ethylene-a-olefin copolymer rubber, which is difficult to disperse uniformly, was obtained. In addition, they have found that a rubber composition containing a specific graft copolymer gives a crosslinked product which is excellent in ozone resistance, mechanical strength and extensibility and does not substantially cause delamination. Based on this, the present invention has been completed.

[0006] According to the present invention, there is provided a composition comprising a nitrile copolymer rubber (A), a copolymer rubber of ethylene and olefin (B), and a graft copolymer (C). And

The graft copolymer (C) is selected from the group consisting of a, j3-ethylenically unsaturated monomer and aromatic vinyl monomer as a copolymer of ethylene and one-year-old olefin having 4 or more carbon atoms. It is obtained by copolymerizing at least one kind of monomer, and is a total of β-ethylenically unsaturated monomer units and aromatic butyl monomer units in the graft copolymer (C). The content is 1060% by weight, and the content of the graft copolymer (C) is 100 parts by weight based on the total of the nitrile copolymer rubber (と) and the copolymer rubber of ethylene and thiolefin (Β). 1 to 30 parts by weight,

The total amount of the copolymer rubber (beta) of the nitrile copolymer rubber (Alpha) and ethylene and α- Orefuin, nitrile copolymer rubber content of (Alpha) is 50- 80 wt ^_0/0, ethylene and α - the rubber composition the copolymer rubber (beta) is a 20-50 weight ^_0/0 of the O-les fins are provided.

[0007] Further, according to the present invention, there is provided a crosslinked molded article obtained by crosslinking and molding a crosslinkable rubber composition obtained by mixing a crosslinking agent with the above rubber composition.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] The rubber composition of the present invention comprises a nitrile copolymer rubber (Α), a copolymer rubber of ethylene and olefin (Β), and a graft copolymer rubber (C).

[0009] The nitrile copolymer rubber (以下) (hereinafter sometimes abbreviated as rubber (Α)) used in the present invention comprises a, j3-ethylenically unsaturated nitrile monomer unit, It preferably contains 3080% by weight, more preferably 33-60% by weight, of a copolymerizable monomer unit and a tertiary // 3-ethylenically unsaturated nitrile monomer unit. If the content of a, / 3-ethylenically unsaturated nitrile monomer unit is too small, the cross-linked molded product is inferior in oil resistance, and conversely, if it is too large, it is inferior in cold resistance.

[0010] The nitrile copolymer rubber (A) is obtained by copolymerizing a, i3-ethylenically unsaturated nitrile monomer and a monomer copolymerizable therewith, and, if necessary, a main chain. Carbon-carbon unsaturated bond Can be obtained by hydrogenation. Examples of the a, i3_ethylenically unsaturated nitrile monomer include atalylonitrile, metharylonitrile, and _α- chloroacrylonitrile. Of these, acrylonitrile is preferred.

[0011] Examples of monomers which can be copolymerized with the a, j3-ethylenically unsaturated nitrile monomer include a co-gen monomer, a non-conjugated di-monomer, a olefin, an aromatic butyl monomer, Monomer, fluorine-containing monomer, _, ethylenically unsaturated monocarboxylic acid, ，, / 3-ethylenically unsaturated polycarboxylic acid and its anhydride, ，, 33 ethylenic Examples include unsaturated carboxylic acid ester monomers and copolymerizable antioxidants. Among these, conjugated diene monomers are preferred. The content of these monomer units in the nitrile copolymer rubber (A) is preferably 70 to 20% by weight, and more preferably 4065% by weight.

[0012] Preferred examples of the conjugated diene monomer include those having 418 carbon atoms, such as 1,3_butadiene, isoprene, 2,3_dimethinole-1,3_butadiene, 1, 3_ pentagen and others. Among them, 1,3-butadiene is particularly preferred.

[0013] The non-conjugated diene monomer preferably has 5 to 12 carbon atoms, and specific examples thereof include 1,4-pentadiene, 1,4-hexadiene, biernorbornene, and dicyclopentadiene. be able to.

[0014] Examples of the α-olefin include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-otaten, which preferably have 3 to 12 carbon atoms.

As the aromatic vinyl monomer, one having 8 to 16 carbon atoms is preferable. Specific examples thereof include styrene, α-methylstyrene, and bierpyridine. As the fluorine-containing monomer, a monomer having 2 to 12 carbon atoms is preferred. Specific examples thereof include phenolic vinyl ether, fluorpropyl butyl ether, ο_trifluoromethyl styrene, pentafluorobenzoic acid Bull, difluoroethylene, tetrafluoroethylene and the like can be mentioned.

[0015] h, j3-Ethylenically unsaturated monocarboxylic acids are preferably those having 38 carbon atoms. Specific examples thereof include acrylic acid and methacrylic acid. As the α, β-ethylenically unsaturated polycarboxylic acid, those having 412 carbon atoms are preferred. Specific examples thereof include itaconic acid, fumaric acid, and maleic acid. a, / 3—Echile The anhydride of the unsaturated unsaturated polycarboxylic acid preferably has 5 to 12 carbon atoms. Specific examples thereof include itaconic anhydride and maleic anhydride.

[0016] a, β The ethylenically unsaturated carboxylic acid ester monomer includes one having 1 carbon atom such as methyl acrylate, ethyl acrylate, η-dodecyl acrylate, methyl methacrylate, and ethyl methacrylate. (Meth) acrylates having an alkyl group of 18; (meth) acrylates having an alkoxyalkyl group having a carbon number of 212, such as methoxymethyl acrylate and methoxyethyl methacrylate; cyanoethyl acrylate (Meth) acrylates having a cyanoalkyl group having 2 to 12 carbon atoms, such as j3-cyanoethyl acrylate, cyanobutyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2 —Having a hydroxyalkyl group with 11 to 12 carbon atoms, such as hydroxyxethyl metathallate ( (T) acrylates; monoalkyl esters of β-ethylenic dicarboxylic acid having an alkyl group of 118 carbon atoms, such as monoethyl maleate and mono-n-butyl itaconate; dimethyl maleate, dimethyl fumarate, itaconic acid Α, β ethylenic dicarboxylic acid dialkyl esters having an alkyl group of 118 carbon atoms, such as dimethyl and getyl itaconate; and 2-12 carbon atoms such as dimethylaminomethyl acrylate, getylaminoethyl acrylate. Cx, β-ethylenically unsaturated carboxylic acid ester having an alkylaminoalkyl group or an aminoalkyl group; having a fluoroalkyl group having 118 carbon atoms such as trifluoroethyl acrylate or tetrafluoropropyl methacrylate (meth) Atarilate; and Fluorobenzyl Examples include fluorine-substituted benzyl (meth) acrylates such as acrylates and fluorobenzyl methacrylates.

[0017] Specific examples of the copolymerizable antioxidant include Ν_ (4-anilinophenyl) acrylamide, Ν— (4-anilinophenyl) methacrylamide, Ν— (4-anilinophenyl) cinnamamide, and Ν— (4-anilinophenyl) Examples thereof include crotonamide, ビ -phenyl-4- (3-butylbenzyloxy) aniline, 二 -phenyl-4_ (4-butylbenzyloxy) aniline, and the like.

[0018] The rubber (重量) has a weight average molecular weight of preferably 50,000 to 3,000,000 in terms of standard polystyrene, which is measured by gel 'permeation' chromatography (GPC), and is more preferable. Is 70,000—2,000,000, more preferably 100,000 1,500,000 It is.

[0019] Further, the viscosity of the rubber (A) (ML, 100

1 + 4. C) is preferably 10-300, more preferably 20-250, particularly preferably 30-200. If the Mooney viscosity is too low, the mechanical properties of the crosslinked product may be poor, and if it is too high, the processability may be poor.

[0020] The copolymer rubber (B) of ethylene and olefin used in the present invention (hereinafter, abbreviated as rubber (B) S) can be copolymerized with ethylene, olefin and, if necessary, these. It is a rubber obtained by copolymerizing various monomers.

[0021] The number average molecular weight of the rubber (B) is measured by gel permeation chromatography, and is preferably 50,000 to 500,000, more preferably 60,000 to 300,000, as converted into standard polystyrene. , Especially preferred <is 70,000-200,000. If the number average molecular weight of the rubber (B) is too small, the crosslinked molded product will have poor mechanical strength, while if too large, the processability as a molding material will be poor.

[0022] α-olefins having 3 to 20 carbon atoms are preferred, and specific examples thereof include 1-propene, isobutylene, 1-butene, 1-hexene, 4-methynoleic 1_pentene, and 1-otaten. .

[0023] rubber) content of the ethylene units is preferably in the range of 50 to 99 weight ^_0/0, more preferably 6 0 97% by weight, particularly preferably 65 - 95 wt%. The content of α-olefin units is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, and particularly preferably 5 to 35% by weight. If the content of α-refin units in the rubber is too small, the mechanical strength of the crosslinked molded article will be poor, and if it is too large, the cold resistance will be poor.

[0024] The rubber (II) may be a copolymer of ethylene and another monomer copolymerizable with α-olefin, as long as the effect of the present invention is not substantially impaired. ,. Such “other monomers” include aromatic butyl monomers such as styrene, halogen-substituted styrene, and alkyl-substituted styrene; and benzenes such as butadiene, 1,4-hexadiene, and dicyclopentadiene. Monomers: Cycloolefin monomers such as cyclopentene, cyclohexene and cyclootaten are exemplified. The amount of these "other monomers" is preferably 30% by weight.

[0025] The method for producing the rubber (されず) is not particularly limited, and may be usually copolymerized by a known method. Manufactured by solution polymerization.

[0026] The graft copolymer (C) used in the present invention is obtained by adding a, an ethylenically unsaturated monomer and an aromatic vinyl monomer to a copolymer of ethylene and an α-olefin having 4 or more carbon atoms. It is obtained by copolymerizing at least one selected monomer.

[0027] As a olefin having 4 or more carbon atoms, a olefin having 4 to 10 carbon atoms is preferable. Specific examples thereof include isobutylene, 1-butene, 1-hexene, 4-methylinole 1_pentene, and 1-pentene. — Otatin and the like. Among these, 1-otaten is particularly preferred.

[0028] The copolymer of ethylene and a one-year-old olefin having 4 or more carbon atoms used in the production of the graft copolymer (C) is ethylene and carbon atoms within a range that does not substantially impair the effects of the present invention. It may be a copolymer of another monomer copolymerizable with four or more olefins. An example of such another monomer is a copolymerizable monomer in the rubber (B). The same as those exemplified as the monomer can be used. The amount of such other monomer units in the copolymer is preferably at most 30% by weight.

The above copolymer of ethylene and α-olefin having 4 or more carbon atoms has a Mooney viscosity (ΜL, 100 ° C.) power of preferably 5 to 50, more preferably 10 to 45, and still more preferably 15 to 45. — 40

1 + 4

It is.

[0030] At least one monomer selected from α, ethylenically unsaturated monomers and aromatic vinyl monomers is added to the above-mentioned copolymer of ethylene and α-olefin having 4 or more carbon atoms. Graft copolymer (C) obtained by copolymerization has Mooney viscosity (ML, 100 ° C)

1 + 4, preferably 5-240, more preferably 10-200, even more preferably 15-180. If the viscosity of the graft copolymer (C) is too small, the mechanical properties of the crosslinked molded product may be poor, and if too large, the workability of the rubber composition may be poor.

[0031] Examples of the a, β-ethylenically unsaturated monomer include acrylonitrile and methacrylonitrile.

Iii, / 3 _ ethylenically unsaturated nitrile monomer; methacrylic acid, and methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; acrylic acid, and methyl acrylate, ethyl acrylate, butyl ataly Acrylates such as acrylates; acrylamide, methacrylamide; vinyl ethers such as methyl butyl ether; vinyl ketones such as methyl vinyl ketone; and vinyl esters such as butyl pyridine and butyl acetate. . Among them, acrylonitrile is particularly preferred.

[0032] Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, and nucleus-substituted styrene. Of these, styrene is particularly preferred.

[0033] There is no particular limitation on the method for copolymerizing the above-mentioned j3_ethylenically unsaturated monomer and / or aromatic vinyl monomer with a copolymer of ethylene and carbon olefin having 4 or more carbon atoms. A known method can be used. Specifically, (1) when copolymerizing ethylene and a one-year-old olefin having 4 or more carbon atoms, copolymerize a, j3_ethylenically unsaturated monomer and / or aromatic butyl monomer. Method, (2) a method of graft-adding a β-ethylenically unsaturated monomer and a ビ or aromatic vinyl monomer to a copolymer of ethylene and a polyolefin having 4 or more carbon atoms. be able to. In the method (1), the copolymerization method may be any method such as emulsion polymerization and solution polymerization. In the method (2), the graft addition reaction method may be a method using heat, an electron beam or an electron beam. Methods using ultraviolet light, methods combining these, and deviations.

The graft copolymer (C) has a total content of α, β-ethylenically unsaturated monomer units and aromatic butyl monomer units of 10 to 60% by weight, preferably, It is 20-55% by weight, more preferably 25-55% by weight. If the total content of these monomer units in the graft copolymer (C) is too small, the compatibility between the graft copolymer (C) and the rubber (Α) deteriorates. If the total content of the body units is too large, the compatibility between the graft copolymer (C) and the rubber (Β) decreases and the rubber composition becomes hard.

[0035] In the rubber composition of the present invention, the content of the graft copolymer (C) is 100% in total of the nitrile copolymer rubber (Α) and the copolymer rubber (エチレン) of ethylene and α-olefin. The amount is 1 to 30 parts by weight, preferably 2 to 20 parts by weight, particularly preferably 315 parts by weight with respect to parts by weight. If the content of the graft copolymer (C) is too small, the ozone resistance of the crosslinked molded product is poor, and if it is too large, the oil resistance is poor.

[0036] Further, the rubber composition of the present invention contains nitrile copolymer rubber (Α) with respect to the total amount of nitrile copolymer rubber (Α) and copolymer rubber of ethylene and polyolefin (Β). the amount of 50 80 wt%, preferably 53- 78% by weight, especially preferably 55 75 wt%, Echire Ntohi - copolymer rubber of Orefuin (beta) is 20-50 weight ^_0/0, preferably 22- 47 weight ^_0/0, Particularly preferably, it is 25 to 45% by weight. If the content of the rubber (A) in the rubber composition is too small, the crosslinked molded article will have poor oil resistance, and if it is too large, the ozone resistance will be poor. When the content of the rubber (B) is too small, the bending fatigue property of the cross-linked molded product is poor, and when it is too large, the mechanical strength is poor.

[0037] The rubber composition of the present invention can be made into a crosslinkable rubber composition by blending a crosslinking agent. Examples of the crosslinking agent include a sulfur-based crosslinking agent, an organic peroxide, and a polyamine-based crosslinking agent.

[0038] Examples of the sulfur-based crosslinking agent include sulfur such as powdered sulfur and precipitated sulfur; and organic sulfur compounds such as 4,4'-dithiomorpholinide.

[0039] Examples of the organic peroxide include dialkyl peroxides, disilver oxides, and peroxyesters. Specific examples of dialkyl peroxides include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5_di (t-butylperoxy) _3-hexyne, 2,5-dimethyl-2,5- Di (t-butylperoxy) hexane, 1,3-bis (t_butylperoxyisopropyl) benzene and the like. Specific examples of disilver oxide include benzoyl peroxide and isobutylinoleoxide. Specific examples of the peroxyester include 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t_butylperoxyisopropylcarbonate and the like.

[0040] A polyamine-based cross-linking agent is a compound having two or more amino groups, in which a plurality of hydrogens of an aliphatic hydrocarbon or an aromatic hydrocarbon are represented by an amino group or a hydrazide structure, that is, one CONHNH. It has been replaced with the following structure. Polyamine-based crosslinking agents include aliphatic

Two

Examples include polyamines, aromatic polyamines, and compounds having two or more hydrazide structures. Specific examples of the aliphatic polyamines include hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, hexamethylene diamine-cinnam aldehyde adduct, and hexamethylene diamine dibenzoate salt. And the like. Specific examples of aromatic polyvalent amines include 4,4′-methylenedianiline, 4,4′-oxydiphenylamine, m-phenylenediamine, p-phenylenediamine, 4,4,1-methylenebis (o —K Mouth roaniline) and the like. Specific examples of the compound having two or more hydrazide structures include isophthalic dihydrazide, adipic dihydrazide, and sebacic dihydrazide.

[0041] The amount of the cross-linking agent used varies depending on the type of the cross-linking agent, but is generally preferably 0.110 parts by weight, more preferably 0.3-1.0 parts by weight, per 100 parts by weight of the rubber composition of the present invention. 7 parts by weight, particularly preferably 0.5-5 parts by weight. If the amount of the cross-linking agent is too small, the cross-linking density becomes low, and the cross-linked molded article may have poor oil resistance. On the other hand, if the amount is too large, the bending fatigue resistance is poor.

When a sulfur-based crosslinking agent is used, a crosslinking accelerator is usually used in combination. Examples of the crosslinking accelerator include zinc white, sulfenamide-based crosslinking accelerator, guanidine-based crosslinking accelerator, thiazole-based crosslinking accelerator, thiuram-based crosslinking accelerator, and dithioate-based crosslinking accelerator. The amount of the cross-linking accelerator used is not particularly limited, and may be determined according to the use of the cross-linked molded article, the required performance, the type of the sulfur crosslinking agent, the type of the cross-linking accelerator, and the like.

When an organic peroxide is used, a crosslinking aid is usually used in combination. Examples of the crosslinking aid include triaryl cyanurate, trimethylolpropane trimetatalate, N, N'-m-phenylenebismaleimide and the like. These may be dispersed in clay, calcium carbonate, silica, or the like to improve the processability of the rubber composition. The amount of the crosslinking aid used is not particularly limited, and may be determined according to the use of the crosslinked product, the required performance, the type of the crosslinking agent, the type of the crosslinking aid, and the like.

[0044] The rubber composition of the present invention contains a compounding agent used for general rubber, for example, a reinforcing agent such as carbon black or silica, as long as the effects of the present invention are not substantially impaired; , Clay, talc, calcium silicate and the like; α, monounsaturated carboxylic acid metal salt; plasticizer; Further, a rubber or resin other than the rubber (A), the rubber (B) and the graft copolymer (C) may be contained as long as the effects of the present invention are not substantially impaired.

[0045] The method for preparing the rubber composition of the present invention is not particularly limited, and a general method for preparing a rubber composition may be employed similarly to other rubber compositions. For kneading, an internal mixer or an open roll may be used. When compounding a cross-linking agent, a cross-linking aid, a cross-linking accelerator, etc., after mixing, the temperature is adjusted so as to be equal to or lower than the cross-linking start temperature and mixed. [0046] The crosslinked molded product of the present invention is obtained by crosslinking the above-described rubber composition of the present invention. The method for cross-linking the rubber composition is not particularly limited, and the cross-linking force can be obtained by a general rubber cross-linking method.

[0047] The temperature at the time of crosslinking is preferably 100 to 200 ° C, more preferably 130 to 190 ° C, and particularly preferably 140 to 180 ° C. If the temperature is too low, the crosslinking time may be long, or the bridge density may be low. Conversely, if the temperature is too high, molding failure may occur. The crosslinking time varies depending on the crosslinking method, crosslinking temperature, shape and the like, but is preferably in the range of 1 minute or more and 5 hours or less from the viewpoint of crosslinking density and production efficiency.

[0048] Also, depending on the shape and size of the molding, even if the surface is cross-linked, it may be sufficiently cross-linked to the inside even if the surface is cross-linked. .

The heating method for cross-linking may be appropriately selected from methods used for cross-linking rubber, such as press heating, steam heating, oven heating, and hot air heat.

Example

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. Parts and percentages are by weight unless otherwise indicated. In addition, the test method etc. were performed as follows.

[0050] (Weight average molecular weight)

It was measured by gel permeation chromatography (GPC) as a standard polystyrene equivalent value.

[0051] (M12 viscosity)

Mooney viscosity (ML, 100 ° C) was measured according to JIS K6300.

1 + 4

[0052] (Ozone resistance)

According to JIS K6259, prepare a test piece described in JIS4 and hold it in an environment with an ozone concentration of 80 pphm, a temperature of 40 ° C, and an elongation of 40%, and cracks at 72 hours and 120 hours after the start of holding Was evaluated according to Table 1 of JIS K6259. NC indicates that no crack occurs, and A-1, A-2, and A-3 indicate the state of the crack. The larger the numerical value from A-1 to A-3, the larger the crack cracks, but none of the specimens broke. CUT indicates that the test piece was broken by a crack.

(Laminar exfoliation) The crosslinkable rubber composition was calo-heated at a press pressure of 12 MPa and 160 ° C. for 20 minutes to prepare a 4 mm-thick 25 mm × 150 mm sheet-like crosslinked molded product. Leave this cross-linked molded product at 23 ° C or 100 ° C, make a cut formed in the center of the corner in the thickness direction, parallel to the upper and lower surfaces, and cut the upper and lower corners separated by this cut. Each was attached to a gripper for a tensile tester and pulled up and down at 50 mm per minute using a tensile tester, and the state where the above-mentioned cuts proceeded further and the sheet was broken was observed. Then, it was determined that the sheet could be easily separated into two sheets and the layer could be easily peeled off in layers.

Production Example 1 “Preparation of nitrile copolymer rubber (A)”

According to the following polymerization recipe, an emulsion polymerization reaction was carried out in a pressure vessel at 5 ° C to a polymerization conversion of 84% to obtain an emulsion of acrylonitrile-butadiene rubber (NBR). The pH of the reaction solution was adjusted to 10.5 before polymerization.

[0055] Combination prescription m)

Cumene Hydrate Peroxide (polymerization initiator) 01

Ferrous sulfate (reducing agent) 0.01

Tododecyl mercaptan (molecular weight modifier) 0 · 5

Sodium otatyl sulfate 2.0

Deionized water 190

Atarilonitrino 33

Butadiene 67

[0056] The resulting emulsion was poured into an aqueous solution of calcium chloride (coagulant) to obtain a polymer crumb slurry (aqueous dispersion). The polymer crumb slurry was filtered through a wire mesh to remove the water containing a coagulant (serum water), and the polymer crumb was recovered. Water was added to the collected polymer crumb, and the mixture was sufficiently stirred and washed with water. Then, the polymer crumb slurry was filtered through a wire mesh to remove the ceramic water, and the polymer crumb was recovered. The recovered polymer crumb was dried under reduced pressure at 50 ° C. to obtain a nitrile copolymer rubber (al). The weight average molecular weight of nitrile copolymer rubber (al), that is, acrylonitrile-butadiene rubber was 400,000.

Production Example 2 “Preparation of Graft Copolymer (C)”

A stainless steel autoclave equipped with a temperature control jacket and ribbon-type stirring blades 300 parts of a toluene solution containing 70 parts of a homogeneously dissolved ethylene-otaten copolymer (ethylene 60%, Mooney viscosity 23) were charged, and 20 parts of styrene, 10 parts of acrylonitrile, and 0.5 part of benzoyl peroxide were added. Then, the polymerization reaction was carried out at 80 ° C for 7 hours, and further heated to 100 ° C for 4 hours. The conversion was 94%.

[0058] From the viscous solution taken out, toluene and residual monomers were removed by steam distillation, and the resulting solution was pulverized thoroughly. After drying all day and night at C, a graft copolymer (cl) having a styrene and acrylonitrile content of 30% was obtained.

The measured viscosity (ML, 100 ° C) of the obtained graft copolymer (C) was measured.

1 + 4

The results are shown in Table 1.

Production Example 3 “Preparation of Graft Copolymer (C)”

A graft polymer (c2) was obtained in the same manner as in Production Example 2 except that the amount of ethylene-otaten copolymer was changed to 50 parts, styrene was changed to 35 parts, and acrylonitrile was changed to 15 parts.

Production Example 4 “Preparation of Graft Copolymer (C)”

A graft polymer (c3) was obtained in the same manner as in Production Example 2, except that 70 parts of an ethylene-otaten copolymer, 10 parts of styrene, 10 parts of acrylonitrile, and 10 parts of butytalylate were used.

[0061] Production Example 5 "Preparation of graft copolymer (c)"

A graft polymer (c4) was obtained in the same manner as in Production Example 2, except that 35 parts of an ethylene-otaten copolymer, 45 parts of styrene, and 20 parts of acrylonitrile were used.

[0062] »[Preparation of graft copolymer (C)]

A graft polymer (c5) was obtained in the same manner as in Production Example 2, except that 50 parts of an ethylene-propylene copolymer (70% of ethylene), 20 parts of styrene, and 30 parts of atarilonitrile were used.

Example 1

Rubber (al) 70 parts prepared in Production Example 1, rubber (B) (Ethylene-propylene-gen rubber (E PT4070, manufactured by Mitsui Chemicals, Inc., ethylene unit content 59%, propylene unit content 30%, iodine value 22, 22, number average molecular weight) 90, 000)) 30 parts, 5 parts of the graft polymer (cl) prepared in Production Example 2, 1 part of stearic acid, 5 parts of zinc oxide (Zinc Hua No. 1, Seido Kagaku), carbon black (Steast 3, 40 parts, dibutyl diglycol adipate (made by Tokai Carbon Co., Ltd.) 107, 5 parts of Asahi Denka Co., plasticizer), 5 parts of naphthenic oil (Sansen 415, Nippon Sun Oil Co., Ltd., softener) and 1 part of diphenylamine derivative (Antage OD, Kawaguchi Chemical Co., antioxidant) Was kneaded for 5 minutes while controlling the temperature at 50 ° C in a Banbury. Then, 1 part of sulfuric acid (325 mesh passed), 2 parts of N-cyclohexyl-2-benzothiazolylsulfenamide (crosslinking accelerator) and 0.2 parts of tetraethylthiuram disulphide (crosslinking accelerator) Roll kneading was performed at 50 ° C to prepare a rubber composition.

The rubber composition was press-crosslinked at 160 ° C. for 20 minutes under a press pressure of lOMPa to obtain a sheet. After preparing each test piece, ozone resistance and delamination were evaluated. The results are shown in Table 1.

[0065]

Example 1 was repeated except that the graft copolymer (c2) prepared in Production Example 3 and the graft polymer (c3) prepared in Production Example 4 were used instead of the graft copolymer (cl). Similarly, a rubber composition was prepared, a sheet was obtained, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0066] Comparative Example 1, Comparative Example 2

Example 1 was repeated except that the graft copolymer (c4) prepared in Production Example 5 and the graft polymer (c5) prepared in Production Example 6 were used instead of the graft copolymer (cl). Similarly, a rubber composition was prepared, a sheet was obtained, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0067] Graft sharing This special example Example 1 Example 2 Example 3

Main Town EOR EOR EOR EOR EPR Side Town SVA S1 AN S1 AN / ¾ a S St AN Copolymerization Ratio 70X20 / 10) 50 / (35/15) 70 / (10/10/10) 35 (45 / ^ 0) 50/20 ^ 0} Polymer viscosity 85 160 60 200 ku 200 <〈100. C, ML _{1 + 4} )

Crosslinked rubber

Ozone resistance NC NC NC A -3 A-1 Delamination No No Yes Yes Yes [0068] Explanations of words, symbols, and the like in the table are as follows.

EOR: ethylene otene copolymer, EPR: ethylene propylene copolymer, St: styrene, AN: acrylonitrile, Ba: butyl acrylate

[0069] As can be seen from Table 1, a cross-linked molded product of a rubber composition in which the graft copolymer content of styrene and acrylonitrile in the graft copolymer (C) exceeds 60% is inferior in ozone resistance and delaminated. The phenomenon is observed (Comparative Example 1). In addition, a cross-linked molded product of a rubber composition having less than 4 carbon atoms in the copolymer of the main chain polymer of the graft copolymer (C) does not sufficiently improve the delamination phenomenon (Comparative Example 2). .

[0070] On the other hand, the crosslinked molded article of the present invention has excellent ozone resistance and improved delamination (Examples 13 to 13).

Industrial applicability

[0071] The cross-linked molded product of the present invention is excellent in oil resistance, ozone resistance, mechanical strength and extensibility, and hardly causes delamination. Therefore, the crosslinked molded product of the present invention is suitably used as an industrial material such as a roll, a hose, a belt, and a sealing material as a substitute for chloroprene rubber. Specifically, it is particularly suitable as a rubber part for automobiles such as a knocking, a fuel hose, an air intake hose, an air duct hose, a hood, and an automobile interior member.

Claims

The scope of the claims

[1] A composition comprising a nitrile copolymer rubber (A), a copolymer rubber of ethylene and thiolefin (B), and a graft copolymer (C),

The graft copolymer (C) is selected from the group consisting of a, j3-ethylenically unsaturated monomer and aromatic vinyl monomer as a copolymer of ethylene and one-year-old olefin having 4 or more carbon atoms. It is obtained by copolymerizing at least one kind of monomer, and comprises a, β-ethylenically unsaturated monomer unit and aromatic vinyl monomer unit in the graft copolymer (C). The total content is 10 to 60% by weight, and the content of the graft copolymer (C) is 100 parts by weight of the nitrile copolymer rubber (Α) and the copolymer rubber of ethylene and α-olefin (Β). 1 to 30 parts by weight,

The total amount of the copolymer rubber (beta) of the nitrile copolymer rubber (Alpha) and ethylene and α- Orefuin, nitrile copolymer rubber content of (Alpha) is 50- 80 wt ^_0/0, ethylene and α -20-50 weight ⁰ / copolymer rubber (Β) with olefin. A rubber composition which is

[2] Nitrile copolymer rubber (Α) is a, i3 _ ethylenically unsaturated nitrile monomer unit

2. The rubber composition according to claim 1, which is a copolymer comprising 30 to 80% by weight and 70 to 20% by weight of a unit of a monomer copolymerizable therewith, or a hydride of the copolymer.

[3] The j3-ethylenically unsaturated nitrile monomer used in the preparation of nitrile copolymer rubber (A)

, Acrylonitrile, methacrylonitrile, and acrylonitrile monochloride, and the copolymerizable monomer is a conjugated diene monomer, a non-conjugated diene dimer, hyolefine, or an aromatic butyl monomer. A, β-ethylenically unsaturated carboxylic acid, or a j-ethylenically unsaturated monocarboxylic acid or an anhydride thereof, a, β-ethylenically unsaturated carboxylic acid 3. The rubber composition according to claim 2, which is selected from an ester monomer and a copolymerizable antioxidant.

[4] The monomer according to claim 2, wherein the monomer copolymerizable with the / 3-ethylenically unsaturated nitrile monomer used for preparing the nitrile copolymer rubber (ゴム) is a conjugated diene monomer. Rubber composition.

[5] the copolymer rubber of ethylene and alpha-Orefuin (beta) is an ethylene 50- 99 weight ^_0/0, a carbon number of three to 20 alpha-Orefuin 1 one 50% by weight and the copolymerizable other these 15. The rubber composition according to claim 14, which is a copolymer comprising 0 to 30% by weight of a monomer.

[6] The copolymer according to claim 115, wherein the copolymer of ethylene and an α-olefin having 4 or more carbon atoms used for the preparation of the graft copolymer (C) is a copolymer of ethylene and 11-otene. The rubber composition according to any one of the above.

[7] When the graft copolymer (C) is used to copolymerize (1) ethylene with a one-year-old refine having 4 or more carbon atoms, j, 3-ethylenically unsaturated monomer and aromatic butyl A method in which at least one monomer selected from monomers is copolymerized, or (2) a copolymer of ethylene and a olefin having 4 or more carbon atoms, and 17. The rubber composition according to claim 16, which is prepared by a method of grafting at least one monomer selected from a monomer and an aromatic vinyl monomer.

[8] The graft copolymer (C) is obtained by copolymerizing at least one monomer selected from acrylonitrile and styrene with a copolymer of ethylene and one-year-old olefin having 4 or more carbon atoms. The rubber composition according to any one of claims 17 to 17, which is obtained by:

[9] The total content of α, β-ethylenically unsaturated monomer units and aromatic vinyl monomer units in the graft copolymer (C) is 20 to 55% by weight, and the graft copolymer The content of (C) is 2 to 20 parts by weight with respect to 100 parts by weight in total of nitrile copolymer rubber (Α) and copolymer rubber of ethylene and α-olefin (Β). A rubber composition according to any one of the above.

[10] A crosslinked molded article obtained by crosslinking and molding a crosslinkable rubber composition obtained by blending a crosslinking agent with the rubber composition according to any one of claims 11 to 19.

[11] The crosslinked molded article according to claim 10, wherein the crosslinking agent is selected from a sulfur-based crosslinking agent, an organic peroxide, and a polyamine-based crosslinking agent.