JPWO2019163482A1 - Nitrile copolymer rubber composition, crosslinkable rubber composition, rubber crosslinked product, and hose - Google Patents

Abstract

The nitrile copolymer rubber (A) containing less than 40% by weight of the α, β-ethylenically unsaturated nitrile monomer unit and 40% by weight or more of the α, β-ethylenically unsaturated nitrile monomer unit are contained. The nitrile copolymer rubber (B) and the vinyl chloride resin (C) having an average degree of polymerization of 800 or more are contained, and the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) is 100. A nitrile copolymer rubber composition in which the content ratio of the vinyl chloride resin (C) with respect to parts by weight is 35 parts by weight or more.

Description

The present invention relates to nitrile copolymer rubber compositions, crosslinkable rubber compositions, rubber crosslinked products, and hoses.

Conventionally, rubber containing α, β-ethylenically unsaturated nitrile monomer unit and conjugated diene monomer unit (nitrile copolymer rubber) has been used as a rubber having excellent oil resistance, such as a fuel hose. It is used in products. Further, in addition to oil resistance, such rubber products are required to have advanced performances such as processability during molding, strength characteristics as rubber products, and ozone resistance.

For example, Patent Document 1 discloses a rubber composition containing two types of unsaturated nitrile conjugated diene rubber, and a fuel hose using the rubber composition.

Japanese Unexamined Patent Publication No. 2003-306580

However, the conventional nitrile copolymer rubber composition may not be able to maintain its shape at the time of molding, and if it is crosslinked in that state, there is a problem that a rubber crosslinked product having a desired shape cannot be obtained (for example). , Cylindrical uncrosslinked rubber is plastically deformed during molding or leaving, and the cylindrical shape is crushed, etc.). In the conventional nitrile copolymer rubber composition, the uncrosslinked rubber (or crosslinkable rubber composition) is not sufficiently formable, and the rubber crosslinks have sufficient strength characteristics, oil resistance, and ozone resistance. I can't get anything.

An object of the present invention is to provide a nitrile copolymer rubber composition which is excellent in molding processability of an uncrosslinked rubber and excellent in strength characteristics, oil resistance and ozone resistance of a crosslinked rubber.

In order to solve the above problems, one aspect of the present invention is a nitrile copolymer rubber (A) containing less than 40% by weight of α, β-ethylenic unsaturated nitrile monomer unit and α, β-ethylene property. The nitrile copolymer rubber (B) containing 40% by weight or more of an unsaturated nitrile monomer unit and the vinyl chloride resin (C) having an average degree of polymerization of 800 or more are contained, and the nitrile copolymer rubber (A) is contained. ) And the nitrile copolymer rubber (B) in a total of 100 parts by weight, the content ratio of the vinyl chloride resin (C) is 35 parts by weight or more, which is a nitrile copolymer rubber composition.

According to one aspect of the present invention, it is possible to provide a nitrile copolymer rubber composition having excellent molding processability of an uncrosslinked rubber product and excellent strength characteristics, oil resistance and ozone resistance of the crosslinked rubber product.

Hereinafter, embodiments of the present invention will be described in detail.

<Nitrile copolymer rubber composition>
The nitrile copolymer rubber composition according to the embodiment of the present invention comprises a nitrile copolymer rubber (A) containing less than 40% by weight of α, β-ethylenically unsaturated nitrile monomer units, and α, β-. A nitrile copolymer rubber (B) containing 40% by weight or more of an ethylenically unsaturated nitrile monomer unit and a vinyl chloride resin (C) having an average degree of polymerization of 800 or more are contained in the nitrile copolymer rubber (B). The content ratio of the vinyl chloride resin (C) to 100 parts by weight of the total of A) and the nitrile copolymer rubber (B) is 35 parts by weight or more.

<Nitrile copolymer rubber (A)>
The nitrile copolymer rubber (A) used in the present embodiment is a rubber containing at least α, β-ethylenically unsaturated nitrile monomer unit in a proportion of less than 40% by weight. In the present specification, the α, β-ethylenically unsaturated nitrile monomer is a compound having a nitrile group and having a double bond of an α-carbon and a β-carbon with respect to the nitrile group. ..

The content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile copolymer rubber (A) is less than 40% by weight, preferably less than 37% by weight, based on all the monomer units. More preferably, it is less than 35% by weight. If the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit is too high, the molding processability of the obtained rubber crosslinked product and the strength characteristics of the rubber crosslinked product may deteriorate. The lower limit of the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit is not particularly limited, but is preferably 15% by weight or more, more preferably, from the viewpoint of the oil resistance of the obtained rubber crosslinked product. Is 25% by weight or more.

In the embodiment of the present invention, one kind of rubber may be used as the nitrile copolymer rubber (A), but it contains less than 40% by weight of α, β-ethylenically unsaturated nitrile monomer unit. A plurality of types of nitrile copolymer rubber (A) may be mixed and used. When a plurality of types of nitrile copolymer rubber (A) are mixed, the content ratio of α, β-ethylenically unsaturated nitrile monomer unit in the entire mixture of rubbers having different monomer compositions is within the above range. do it. For example, as the nitrile copolymer rubber (A), a rubber (α) having an α, β-ethylenic unsaturated nitrile monomer unit content of 25% by weight and a rubber (β) having a content of 35% by weight. When used in a mixture of 50:50 (weight ratio), the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the entire nitrile copolymer rubber (A) is the rubber (α). , Rubber (β) is 30% by weight. Hereinafter, the same applies to the diene monomer unit, the α-olefin monomer unit, and the like.

The α, β-ethylenically unsaturated nitrile monomer forming the α, β-ethylenically unsaturated nitrile monomer unit is not particularly limited, and for example, acrylonitrile; α-chloroacrylonitrile, α-bromoacrylonitrile, etc. Α-halogenoacrylonitrile; α-alkylacrylonitrile such as methacrylonitrile; and the like. Among these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. These can be used alone or in combination of two or more.

In the present embodiment, the nitrile copolymer rubber (A) preferably has a methyl ethyl ketone insoluble content (hereinafter, may be referred to as MEK insoluble content) of 60% or more, more preferably 70% or more, and further. It is preferably 80% or more. The amount of methyl ethyl ketone insoluble when a plurality of rubbers are mixed and used is calculated from the amount of methyl ethyl ketone insoluble in each rubber and the mixed weight ratio.

The amount of methyl ethyl ketone insoluble (MEK insoluble) is the amount of nitrile copolymer rubber (A) that does not dissolve when the nitrile copolymer rubber (A) is dissolved in the methyl ethyl ketone solvent. When the nitrile copolymer rubber (A) is partially crosslinked, the MEK insoluble content increases.

If the amount of methyl ethyl ketone insoluble is too small, the molding processability of the uncrosslinked rubber product and the strength characteristics of the crosslinked rubber product may not be sufficiently obtained. On the other hand, there is no upper limit to the amount of methyl ethyl ketone insoluble, but it is preferably 90% or less. In general, if the amount of methyl ethyl ketone insoluble is too large, it becomes difficult to mix with other components, and the nitrile copolymer rubber (A) cannot be mixed with other components, which may make it impossible to prepare a rubber composition. There is.

Further, the nitrile copolymer rubber (A) used in the present embodiment also contains a diene monomer unit or an α-olefin monomer unit in order to make the obtained crosslinked rubber have rubber elasticity. Is preferable.

The diene monomer is preferably a conjugated diene having 4 or more carbon atoms, such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene; and 1, Non-conjugated diene having 5 to 12 carbon atoms, such as 4-pentadiene, 1,4-hexadiene, vinylnorbornene, and dicyclopentadiene; can be mentioned. Of these, conjugated diene is preferred, and 1,3-butadiene is more preferred.

The α-olefin monomer preferably has 2 to 12 carbon atoms, and examples thereof include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. ..

The content ratio of the diene monomer unit or the α-olefin monomer unit in the nitrile copolymer rubber (A) is preferably 59% by weight or more, more preferably 61% by weight or more, based on the total monomer units. It is more preferably 64% by weight or more, preferably 78% by weight or less, more preferably 74% by weight or less, still more preferably 70% by weight or less. By setting the content ratio of the diene monomer unit or the α-olefin monomer unit within the above range, the obtained crosslinkable rubber composition is excellent in molding processability, and the strength characteristics and oil resistance of the obtained crosslinked rubber are obtained. It is possible to appropriately improve the rubber elasticity while making it excellent in ozone resistance.

Further, the nitrile copolymer rubber (A) used in the present embodiment includes the α, β-ethylenic unsaturated nitrile monomer unit and the diene monomer unit or the α-olefin monomer unit. It may contain a unit of another monomer copolymerizable with the monomer forming the monomer unit of. The content ratio of such other monomer units is preferably 30% by weight or less, more preferably 20% by weight or less, still more preferably 10% by weight or less, based on all the monomer units.

Examples of such copolymerizable monomers include aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; fluoroethylvinyl ether, fluoropropylvinyl ether, o-trifluoromethylstyrene and pentafluoro. Fluorine-containing vinyl compounds such as vinyl benzoate, difluoroethylene and tetrafluoroethylene; α-olefin compounds such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene; acrylic acid, Α, β-ethylene unsaturated carboxylic acids such as methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, fumaric acid anhydride and their anhydrides; methyl (meth) acrylate, (meth) Α, β-ethylenic unsaturated monocarboxylic acid alkyl esters such as ethyl acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; monoethyl maleate, diethyl maleate, mono n-butyl maleate, Dibutyl maleate, monoethyl fumarate, diethyl fumarate, mono n-butyl fumarate, dibutyl fumarate, monocyclohexyl fumarate, dicyclohexyl fumarate, monoethyl fumarate, diethyl itaconate, mono n-butyl itaconate, dibutyl itaconate Monoesters and diesters of α, β-ethylenic unsaturated polycarboxylic acids such as α, β-ethylene such as methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, butoxyethyl (meth) acrylate. Ekoxyalkyl ester of sex unsaturated carboxylic acid; hydroxyalkyl ester of α, β-ethylene unsaturated carboxylic acid such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate; Divinylbenzene and the like Divinyl compounds; di (meth) acrylic acid esters such as ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate; trimethacrylic acid esters such as trimethyl propantri (meth) acrylate; In addition to polyfunctional ethylenically unsaturated monomers such as, self-crosslinking compounds such as N-methylol (meth) acrylamide and N, N'-dimethylol (meth) acrylamide; and the like.

In addition, in this specification, "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid". Thus, for example, methyl (meth) acrylate represents methyl acrylate and / or methyl methacrylate.

Of these, it is preferable to copolymerize a monomer having at least two polymerizable unsaturated groups, and among them, polyfunctional ethylene such as a divinyl compound; di (meth) acrylic acid esters; trimethacrylic acid esters; It is preferable to copolymerize the sex-unsaturated monomer, and it is particularly preferable to copolymerize the trimethylpropantri (meth) acrylate. The content ratio of these monomer units is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and preferably 5% by weight or less, more preferably 3% by weight or less. .. The amount of methyl ethyl ketone insoluble can be adjusted by these copolymerizations.

The Mooney viscosity (polymer Mooney) (ML1 + 4, 100 ° C.) of the nitrile copolymer rubber (A) is usually 3 or more, preferably 15 or more, more preferably 30 or more, particularly preferably 50 or more, and usually. It is 250 or less, preferably 180 or less, more preferably 150 or less, and particularly preferably 100 or less. If the polymer Mooney viscosity of the nitrile copolymer rubber (A) is too low, the strength characteristics of the obtained rubber crosslinked product may deteriorate. On the other hand, if the polymer Mooney viscosity is too high, the molding processability may decrease. The Mooney viscosity of the nitrile copolymer rubber (A) can be measured according to, for example, JIS K6300.

The method for producing the nitrile copolymer rubber (A) used in the present embodiment is not particularly limited, but the above-mentioned monomer is copolymerized, and if necessary, a carbon-carbon double in the obtained copolymer. It can be produced by hydrogenating the bond. The polymerization method is not particularly limited and may be a known emulsion polymerization method or solution polymerization method, but the emulsion polymerization method is preferable from the viewpoint of industrial productivity. In the emulsion polymerization, in addition to the emulsifier, the polymerization initiator and the molecular weight modifier, commonly used polymerization auxiliary materials can be used.

The emulsifier is not particularly limited, and is, for example, a nonionic emulsifier such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester; myristic acid, palmitic acid, oleic acid. And salts of fatty acids such as linolenic acid, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, higher alcohol sulfates, anionic emulsifiers such as alkylsulfosuccinates; sulfoesters of α, β-unsaturated carboxylic acids, α , Sulfate ester of β-unsaturated carboxylic acid, copolymerizable emulsifier such as sulfoalkylaryl ether; and the like. The amount of the emulsifier added is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, and preferably 10 parts by weight or less, based on 100 parts by weight of the monomer used for the polymerization. It is preferably 5 parts by weight or less.

The polymerization initiator is not particularly limited as long as it is a radical initiator, but is an inorganic peroxide such as potassium persulfate, sodium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide; t-butyl peroxide, cumene. Hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3, 5, 5 -Organic peroxides such as trimethylhexanoyl peroxide, t-butylperoxyisobutyrate; azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, etc. Azo compounds; etc. can be mentioned. These polymerization initiators can be used alone or in combination of two or more. Inorganic or organic peroxides are preferred as the polymerization initiator. When a peroxide is used as the polymerization initiator, it can also be used as a redox-based polymerization initiator in combination with a reducing agent such as sodium bisulfite or ferrous sulfate.

The amount of the polymerization initiator added is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, still more preferably 0.1 parts by weight or more, based on 100 parts by weight of the monomer used for polymerization. Also, it is preferably 2 parts by weight or less, more preferably 1.5 parts by weight or less, and further preferably 1.0 part by weight or less.

Water is usually used as the medium for emulsion polymerization. The amount of water is preferably 80 to 500 parts by weight, more preferably 80 to 300 parts by weight, based on 100 parts by weight of the monomer used for the polymerization.

In the emulsion polymerization, further, if necessary, polymerization auxiliary materials such as stabilizers, dispersants, pH adjusters, oxygen scavengers, and particle size adjusters can be used. When these are used, the type and amount used are not particularly limited.

Further, in the nitrile copolymer rubber (A) used in the present embodiment, at least a part of the unsaturated bond portion in the diene monomer unit of the copolymer obtained by copolymerization as described above is hydrogenated. It may be a hydride nitrile copolymer rubber (hydrogenation reaction). The method of hydrogenation is not particularly limited, and a known method may be adopted. When the nitrile copolymer rubber (A) is a hydrogenated nitrile copolymer rubber, its iodine value is preferably in the range of 0 or more, more preferably in the range of 4 or more, and preferably 70. The range is as follows, more preferably 60 or less.

When the crosslinkable rubber composition described later is obtained by using the nitrile copolymer rubber composition of the present embodiment, the present embodiment depends on the compounding agent used when obtaining the crosslinkable rubber composition and the like. In addition to the nitrile copolymer rubber (A) contained in the nitrile copolymer rubber composition of the above, the nitrile copolymer rubber (A) is added together with a cross-linking agent and the like when obtaining a crosslinkable rubber composition described later. It may be added.

<Nitrile copolymer rubber (B)>
Further, the nitrile copolymer rubber composition of the present embodiment contains the nitrile copolymer rubber (B) in addition to the above-mentioned nitrile copolymer rubber (A). The nitrile copolymer rubber (B) used in the present embodiment is a rubber containing at least α, β-ethylenically unsaturated nitrile monomer unit in a proportion of 40% by weight or more.

The content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile copolymer rubber (B) is 40% by weight or more, preferably 45% by weight or more, based on the total monomer unit. More preferably, it is 47% by weight or more. If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too low, the molding processability of the obtained uncrosslinked rubber product, the strength characteristics of the crosslinked rubber product, and the oil resistance tend to decrease. On the other hand, the upper limit of the content ratio of the α, β-ethylene unsaturated nitrile monomer unit in the nitrile copolymer rubber (B) of the nitrile copolymer rubber (B) is not particularly limited, but the uncrosslinked rubber product. From the viewpoint of moldability, it is preferably 80% by weight or less, more preferably 70% by weight or less, still more preferably 60% by weight or less, and particularly preferably 55% by weight or less. The content ratio of the nitrile copolymer rubber (B) is preferably 1900 parts by weight or less, more preferably 900 parts by weight or less, based on 100 parts by weight of the nitrile copolymer rubber (A).

In the present embodiment, one kind of rubber may be used as the nitrile copolymer rubber (B), but the nitriles containing 40% by weight or more of α, β-ethylenically unsaturated nitrile monomer units are used. A plurality of types of polymer rubber (B) may be mixed and used. When a plurality of types of nitrile copolymer rubber (B) are mixed, the content ratio of α, β-ethylenically unsaturated nitrile monomer unit in the entire mixture of rubbers having different monomer compositions is within the above range. do it. For example, as the nitrile copolymer rubber (B), a rubber (α) having a content ratio of α, β-ethylenically unsaturated nitrile monomer unit of 55% by weight and a rubber (β) having a content ratio of 45% by weight are used. When used in a mixture of 50:50 (weight ratio), the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the entire nitrile copolymer rubber (A) is the rubber (α). , Rubber (β) is 50% by weight. Hereinafter, the same applies to the diene monomer unit, the α-olefin monomer unit, and the like.

As the α, β-ethylenically unsaturated nitrile monomer forming the α, β-ethylenically unsaturated nitrile monomer unit, the same material as the above-mentioned nitrile copolymer rubber (A) can be used. , Acrylonitrile is preferred.

In addition, the nitrile copolymer rubber (B) used in the present embodiment also contains a diene monomer unit or an α-olefin monomer unit in order to make the obtained crosslinked rubber have rubber elasticity. Is preferable. As the diene monomer unit or the α-olefin monomer unit, the same one as the above-mentioned nitrile copolymer rubber (A) can be used, and 1,3-butadiene is preferable.

The content ratio of the diene monomer unit or the α-olefin monomer unit in the nitrile copolymer rubber (B) is preferably 20% by weight or more, more preferably 30% by weight or more, based on the total monomer units. It is more preferably 40% by weight or more, particularly preferably 45% by weight or more, and preferably 60% by weight or less, more preferably 55% by weight or less, still more preferably 53% by weight or less. By setting the content ratio of the diene monomer unit or α-olefin monomer unit within the above range, the obtained uncrosslinked rubber product is excellent in molding processability, and the strength characteristics, oil resistance, and resistance of the obtained crosslinked rubber product are excellent. It is possible to appropriately improve the rubber elasticity while making it excellent in ozone property.

The nitrile copolymer rubber (B) used in the present embodiment is the same as the nitrile copolymer rubber (A), the above-mentioned α, β-ethylenically unsaturated nitrile monomer unit, and the diene monomer unit or α. -In addition to the olefin monomer unit, it may contain a unit of another monomer copolymerizable with the monomer forming these monomer units. Further, the content ratio of other monomer units contained in such a nitrile copolymer rubber (B) is the same as that of the above-mentioned nitrile copolymer rubber (A) with respect to all the monomer units. It is preferably 30% by weight or less, more preferably 20% by weight or less, still more preferably 10% by weight or less.

Examples of the other copolymerizable monomer contained in the nitrile copolymer rubber (B) include styrene, α-methylstyrene, vinyltoluene and the like, as in the case of the nitrile copolymer rubber (A). Aromatic vinyl compounds; fluoroethyl vinyl ethers, fluoropropyl vinyl ethers, o-trifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene, tetrafluoroethylene and other fluorine-containing vinyl compounds; ethylene, propylene, 1-butene, 4- Α-Olefin compounds such as methyl-1-pentene, 1-hexene, 1-octene; α, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, fumaric acid anhydride, etc. β-Ethenyl unsaturated carboxylic acid and its anhydride; α, β-ethylene such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate. Unsaturated monocarboxylic acid alkyl ester; monoethyl maleate, diethyl maleate, mono n-butyl maleate, dibutyl maleate, monoethyl fumarate, diethyl fumarate, mono n-butyl fumarate, dibutyl fumarate, monocyclohexyl fumarate , Monoesters and diesters of α, β-ethylenic unsaturated polyvalent carboxylic acids such as dicyclohexyl fumarate, monoethyl itaconate, diethyl itaconate, monon-butyl itaconate, dibutyl itaconate; methoxyethyl (meth) acrylate. Alkoxyalkyl esters of α, β-ethylene unsaturated carboxylic acids such as methoxypropyl (meth) acrylate, butoxyethyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 3-hydroxyethyl (meth) acrylate. Hydroxyalkyl esters of α, β-ethylene unsaturated carboxylic acids such as hydroxypropyl; divinyl compounds such as divinylbenzene; di (meth) acrylates, diethylene glycol di (meth) acrylates, ethylene glycol di (meth) acrylates, etc. In addition to polyfunctional ethylenically unsaturated monomers such as meta) acrylic acid esters; trimethacrylic acid esters such as trimethyl propantri (meth) acrylate; N-methylol (meth) acrylamide, N, N'- Self-crosslinking compounds such as dimethylol (meth) acrylamide; and the like.

The Mooney viscosity (polymer Mooney) (ML1 + 4, 100 ° C.) of the nitrile copolymer rubber (B) is usually 3 or more, preferably 15 or more, more preferably 20 or more, particularly preferably 30 or more, and usually. It is 250 or less, preferably 180 or less, more preferably 150 or less, and particularly preferably 120 or less. If the polymer Mooney viscosity of the nitrile copolymer rubber (B) is too low, the strength characteristics of the obtained rubber crosslinked product may deteriorate. On the other hand, if the polymer Mooney viscosity is too high, the molding processability may decrease. The Mooney viscosity of the nitrile copolymer rubber (B) can be measured according to, for example, JIS K6300.

The method for producing the nitrile copolymer rubber (B) used in the present embodiment is not particularly limited, but the same production method as the above-mentioned nitrile copolymer rubber (A) can be used. In this case as well, it can be produced by hydrogenating the carbon-carbon double bond in the obtained copolymer, if necessary. The polymerization method is not particularly limited, and as with the nitrile copolymer rubber (A) described above, a known emulsion polymerization method or solution polymerization method may be used, but from the viewpoint of industrial productivity, the emulsion polymerization method may be used. Is preferable. In the emulsion polymerization, in addition to the emulsifier, the polymerization initiator, and the molecular weight adjusting agent similar to those of the nitrile copolymer rubber (A) described above, a commonly used polymerization auxiliary material can be used.

When the crosslinkable rubber composition described later is obtained by using the nitrile copolymer rubber composition of the present embodiment, the present embodiment depends on the compounding agent used when obtaining the crosslinkable rubber composition and the like. In addition to the nitrile copolymer rubber (B) contained in the nitrile copolymer rubber composition of the above, when the crosslinkable rubber composition described later is obtained, the nitrile copolymer rubber (B) is added together with a crosslinker and the like. It may be added.

Further, it is preferable that the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) contains 35% by weight or more of α, β-ethylenically unsaturated nitrile monomer units, and more preferably 38. By weight% or more, more preferably 40% by weight or more. Here, the fact that the total amount of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) contains 35% by weight or more of the α, β-ethylenically unsaturated nitrile monomer unit means that the nitrile copolymer rubber This means that the total amount of the nitrile copolymer rubber (B) and the α, β-ethylenically unsaturated nitrile monomer unit is contained in an amount of 35% by weight or more.

If the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) is too low, the uncrosslinked rubber product obtained can be formed. Workability and strength characteristics of rubber crosslinked products tend to decrease. On the other hand, although there is no upper limit to the content ratio, the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit is preferably 70% by weight from the viewpoint of mixing with other components and cold resistance of the crosslinked rubber product. % Or less, more preferably 60% by weight or less, still more preferably 55% by weight or less, and particularly preferably 50% by weight or less.

<Vinyl chloride resin (C)>
The nitrile copolymer rubber composition of the present embodiment contains a vinyl chloride resin (C) having an average degree of polymerization of 800 or more, in addition to the above-mentioned nitrile copolymer rubber (A) and nitrile copolymer rubber (B). contains.

The vinyl chloride resin (C) is not particularly limited as long as the main constituent monomer is vinyl chloride and the average degree of polymerization is in the range of 800 or more, but the content of the unit of the main constituent monomer is not particularly limited. Is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and even more preferably 70 to 100% by weight.

The average degree of polymerization of the vinyl chloride resin (C) is 800 or more, preferably 900 or more, more preferably 1300 or more, and particularly preferably 1500 or more. If the average degree of polymerization is too low, the ozone resistance of the obtained rubber crosslinked product will decrease. On the other hand, although there is no upper limit of the average degree of polymerization, it is preferably 2000 or less from the viewpoint of mixing with the nitrile copolymer rubber (A) and / or the nitrile copolymer rubber (B). The average degree of polymerization of the vinyl chloride resin (C) can be measured, for example, by the solution viscosity method specified in JIS K6721. The glass transition temperature (Tg) of the vinyl chloride resin (C) is preferably 50 to 180 ° C.

Further, the vinyl chloride resin (C) used in the present embodiment may be obtained by copolymerizing another monomer copolymerizable with vinyl chloride in addition to vinyl chloride which is the main constituent monomer. .. Examples of such other monomers include (meth) acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group; aromatic vinyl compounds such as styrene, vinyltoluene and α-methylstyrene; acrylonitrile and methacrylonitrile. , Vinyl cyanide compounds such as vinylidene cyanide; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as ethyl vinyl ether, cetyl vinyl ether and hydroxybutyl vinyl ether; α-hydroxyethyl (meth) acrylate, (meth) Examples thereof include hydroxyl group or alkoxy group-containing unsaturated carboxylic acid ester compounds such as 3-hydroxybutyl acrylate and butoxyethyl (meth) acrylate.

The polymerization method for producing the vinyl chloride resin (C) used in the present embodiment is not particularly limited, and examples thereof include emulsion polymerization, seed emulsion polymerization, fine suspension polymerization, and suspension polymerization.

The content of the vinyl chloride resin (C) in the nitrile copolymer rubber composition of the present embodiment is 100 parts by weight in total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). , 35 parts by weight or more, preferably 38 parts by weight or more, and more preferably 40 parts by weight or more. If the content of the vinyl chloride resin (C) is too small, the molding processability of the obtained uncrosslinked rubber product and the strength characteristics of the crosslinked rubber product deteriorate. On the other hand, the upper limit of the content of the vinyl chloride resin (C) is not particularly limited, but is 233 parts by weight from the viewpoint of mixing with the nitrile copolymer rubber (A) and / or the nitrile copolymer rubber (B). Below, it is preferably 150 parts by weight or less, more preferably 100 parts by weight or less, still more preferably 80 parts by weight or less, and particularly preferably 70 parts by weight or less.

Further, in the nitrile copolymer rubber composition of the present embodiment, in addition to the above-mentioned nitrile copolymer rubber (A), nitrile copolymer rubber (B) and vinyl chloride resin (C), other compounding agents are added. It may be contained. Examples of such other compounding agents include plasticizers, antioxidants and stabilizers.

The blending amount of these other blending agents is not particularly limited as long as it does not impair the purpose and effect of the present embodiment, and the blending amount can be blended according to the blending purpose.

Specific examples of the plasticizer include ester compounds of adipic acid such as di (butoxyethyl) adipate and di (butoxyethoxyethyl) adipate and an ether bond-containing alcohol; dibutoxyethyl azereate, di (di (butoxyethoxyethyl) azereate). Ester compounds of azelaic acid such as butoxyethoxyethyl) and ether bond-containing alcohols; ester compounds of sebacic acid and ether bond-containing alcohols such as dibutoxyethyl sebacate and di (butoxyethoxyethyl) sebacate; dibutoxy phthalate Ester compounds of phthalic acid such as ethyl and di (butoxyethoxyethyl) phthalate and ether bond-containing alcohol; ester of isophthalic acid such as dibutoxyethyl isophthalate and di (butoxyethoxyethyl) isophthalate and ether bond-containing alcohol Compounds; Dialkyl esters of adipate such as di- (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, dibutyl adipate; di- (2-ethylhexyl) azereate, diisooctyl azereate, di-n azereate Azelaic acid dialkyl esters such as -hexyl; sebacic acid dialkyl esters such as di-n-butyl sebacate and di- (2-ethylhexyl) sebacate; dibutyl phthalate, di- (2-ethylhexyl) phthalate, phthal Dialkyl esters of phthalates such as di-n-octyl acid, diisobutyl phthalate, diheptyl phthalate, diisodecyl phthalate, diundecyl phthalate, diisononyl phthalate; dicycloalkyl phthalates such as dicyclohexyl phthalate; diphenyl phthalate , Oryl esters of phthalates such as butylbenzyl phthalate; di- (2-ethylhexyl) isophthalates, dialkyl esters of isophthalates such as diisooctyl isophthalate; di- (2-ethylhexyl) tetrahydrophthalates, di-tetrahydrophthalates. Tetrahydrophthalic acid dialkyl esters such as n-octyl and diisodecyl tetrahydrophthalate; tri- (2-ethylhexyl) trimellitic acid, tri-n-octyl trimellitic acid, triisodecyl trimellitate, triisooctyl trimellitic acid, tri Trimeritic acid derivatives such as tri-n-hexyl meritate, triisononyl trimeritate, triisodecyl trimellitate; epoxidized soybean oil, epoxidized amani Epoxy plasticizers such as oil; phosphoric acid ester plasticizers such as tricresyl phosphate; and the like. These can be used alone or in combination of two or more.

Among these, from the viewpoint that the oil resistance of the obtained rubber cross-linked compound can be improved, dibasic acids such as adipic acid, azelaic acid, sebacic acid and phthalic acid and ether bond-containing alcohols are used. The ester compound; is preferable, the ester compound of adipic acid and the ether bond-containing alcohol; is more preferable, and di (butoxyethoxyethyl) adipate is particularly preferable.

The content of the plasticizer in the nitrile copolymer rubber composition of the present embodiment is preferably 1 with respect to 100 parts by weight of the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). By weight or more, more preferably 2 parts by weight or more, still more preferably 3 parts by weight or more, particularly preferably 4 parts by weight or more, and preferably 100 parts by weight or less, more preferably 80 parts by weight or less, still more preferably. It is 60 parts by weight or less, particularly preferably 50 parts by weight or less.
By setting the content of the plasticizer in the above range, the effect of adding the plasticizer can be further enhanced.

In the nitrile copolymer rubber composition of the present embodiment, each component containing the nitrile copolymer rubber (A), the nitrile copolymer rubber (B), and the vinyl chloride resin (C) is preferably mixed in a non-aqueous system. Is prepared by Mixing can be performed using, for example, a mixer such as a Banbury mixer, an internal mixer, or a kneader.

The mixing temperature at the time of mixing each component containing the nitrile copolymer rubber (A), the nitrile copolymer rubber (B), and the vinyl chloride resin (C) is not particularly limited, but is preferably a vinyl chloride resin. It is more preferable to mix at a temperature equal to or higher than the melting point of (C), more preferably 5 ° C. or higher than the softening point of the vinyl chloride resin (C), and more preferably than the softening point of the vinyl chloride resin (C). The temperature is higher than 10 ° C. Specifically, the mixing is preferably performed at 160 ° C. or higher, more preferably at 165 ° C. or higher, and further preferably at 170 ° C. or higher. By mixing at such a temperature, the dispersibility of the vinyl chloride resin (C) in the nitrile copolymer rubber composition can be further enhanced, whereby the obtained rubber crosslinked product is more excellent in ozone resistance. Can be assumed.

Alternatively, in the nitrile copolymer rubber composition of the present embodiment, each component containing the nitrile copolymer rubber (A) and the vinyl chloride resin (C) can be mixed in an aqueous system, in this case. A latex-state vinyl chloride resin (C) produced by a conventionally known emulsion polymerization method or suspension polymerization method on the latex of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) obtained by emulsion polymerization. ) Or by mixing other ingredients (latex blend).

<Crosslinkable rubber composition>
The crosslinkable rubber composition according to the embodiment is formed by blending a crosslinking agent with the nitrile copolymer rubber composition of the present embodiment described above. Examples of the cross-linking agent include sulfur-based cross-linking agents and organic peroxide cross-linking agents. These can be used alone or in combination, but it is preferable to use a sulfur-based cross-linking agent.

Sulfur-based cross-linking agents include sulfur powder, sulfur flowers, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, and other sulfur; sulfur chloride, sulfur dichloride, morpholini disulfide, alkylphenol disulfide, dibenzothiazyl disulfide, and caprolactam disulfide. , Sulfur-containing compounds such as phosphorus-containing polysulfides and high-molecular-weight polysulfides; sulfur-donating compounds such as tetramethylthium disulfide, selenium dimethyldithiocarbamate, and 2- (4'-morpholinodithio) benzothiazole; and the like. These can be used alone or in combination of two or more.

Examples of the organic peroxide peroxide crossing agent include dicumyl peroxide, cumene hydroperoxide, t-butyl cumyl peroxide, p-menthan hydroperoxide, di-t-butyl peroxide, and 1,3-bis (t-butyl peroxyisopropyl) benzene. , 1,4-bis (t-butylperoxyisopropyl) benzene, 1,1-di-t-butylperoxy-3,3-trimethylcyclohexane, 4,4-bis- (t-butyl-peroxy) -n-butyl Valerate, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butylperoxyhexin-3, 1,1-di-t- Examples thereof include butylperoxy-3,5,5-trimethylcyclohexane, p-chlorobenzoyl peroxide, t-butylperoxyisopropyl carbonate, and t-butylperoxybenzoate. These can be used alone or in combination of two or more.

The content of the cross-linking agent in the cross-linkable rubber composition of the present embodiment is 100 in total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) from the viewpoint of obtaining a good rubber cross-linked product. With respect to parts by weight, it is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, still more preferably 0.3 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight. It is less than a part by weight, more preferably 6 parts by weight or less.

When sulfur-based cross-linking agents are used, cross-linking aids such as active zinc oxide, zinc oxide, and stearic acid; guanidine-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, sulfenamide-based, thiourea-based, etc. Cross-linking accelerator; can be used in combination. The amount of these cross-linking aids and cross-linking accelerators used is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). The range.

When an organic peroxide cross-linking agent is used, a polyfunctional monomer such as trimethylolpropane tri (meth) clearate, divinylbenzene, ethylene dimethacrylate, or triallyl isocyanurate may be used in combination as a cross-linking aid. it can. The amount of these cross-linking aids used is preferably in the range of 0.5 to 20 parts by weight with respect to a total of 100 parts by weight of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B).

Further, the crosslinkable rubber composition of the present embodiment may further contain a hydrocarbon wax. By further containing a hydrocarbon-based wax, the obtained crosslinked rubber product can be made more excellent in ozone resistance.

Examples of the hydrocarbon wax include polyolefin waxes such as polyethylene wax and polypropylene wax; Fishertropus wax; petroleum waxes such as paraffin wax and microstalin wax, and among these, Fishertropus wax and petroleum wax are preferable. , Petroleum wax is more preferable.

Further, the crosslinkable rubber composition of the present embodiment preferably contains a plasticizer, and as the plasticizer, the same one as the above-mentioned nitrile copolymer rubber composition can be used. The content of the plasticizer in the crosslinkable rubber composition of the present embodiment is preferably 3 parts by weight with respect to 100 parts by weight in total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). It is more preferably 5 parts by weight or more, further preferably 10 parts by weight or more, preferably 300 parts by weight or less, more preferably 200 parts by weight or less, still more preferably 150 parts by weight or less. .. By setting the content of the plasticizer in the above range, the effect of adding the plasticizer can be further enhanced. The content of the plasticizer in the crosslinkable rubber composition of the present embodiment is such that the total content of the plasticizer with the plasticizer contained in the nitrile copolymer rubber composition of the present embodiment is within the above range. You just have to adjust.

In addition, the crosslinkable rubber composition of the present embodiment includes other compounding agents used for general rubber, for example, a crosslink retardant, a reinforcing agent, a filler, a lubricant, a pressure-sensitive adhesive, and a lubricant, if necessary. Additives such as processing aids, flame retardants, antifungal agents, antistatic agents, colorants, and coupling agents may be added.

The filler is not particularly limited, and a carbon-based material such as carbon black or graphite can be used. Of these, it is preferable to use carbon black. Specific examples of carbon black include furnace black, acetylene black, thermal black, channel black and the like. Among these, furnace black is preferably used, and specific examples thereof include SAF (N110), ISAF (N220), ISAF-HS (N234), ISAF-LS, IISAF-HS, HAF (N330), and HAF-. Examples thereof include HS (N339), HAF-LS (N326), MAF, FEF (N550), SRF (N762, N774) and the like. Specific examples of thermal black include FT, MT (N990) and the like. Specific examples of graphite include natural graphite such as scaly graphite and scaly graphite, and artificial graphite.

Examples of fillers other than carbon-based materials include metal powders such as aluminum powder; inorganic powders such as hard clay, talc, calcium carbonate, titanium oxide, calcium sulfate, calcium carbonate and aluminum hydroxide; and starch and polystyrene powder. Examples include powders such as organic powders; short fibers such as glass fibers (milled fibers), carbon fibers, aramid fibers, and potassium titanate whiskers (the above short fibers); silica, mica; and the like. Of these, silica is preferably used.

Examples of silica include natural silica such as quartz powder and silica stone powder; synthetic silica such as anhydrous silicic acid (silica gel, Aerosil, etc.) and hydrous silicic acid; among these, synthetic silica is preferable. Further, these silicas may be surface-treated with a silane coupling agent or the like.

These fillers are used alone or in combination of two or more. The amount of the filler to be blended is not particularly limited, but is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, based on 100 parts by weight of the nitrile group-containing copolymer rubber from the viewpoint of improving tensile stress. It is more preferably 15 parts by weight or more, preferably 200 parts by weight or less, more preferably 150 parts by weight or less, still more preferably 100 parts by weight or less.

Further, the crosslinkable rubber composition of the present embodiment may contain a rubber other than the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) as long as the effects of the present embodiment are not impaired. Good. Examples of rubbers other than the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) include acrylic rubber, ethylene-acrylic acid copolymer rubber, fluororubber, styrene-butadiene copolymer rubber, polybutadiene rubber, and ethylene. -Propine copolymer rubber, ethylene-propylene-diene ternary copolymer rubber, epichlorohydrin rubber, urethane rubber, chloroprene rubber, silicone rubber, fluorosilicone rubber, chlorosulfonated polyethylene rubber, natural rubber and polyisoprene rubber, etc. Can be mentioned. When a rubber other than the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) is blended, the blending amount is 100 weight in total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). With respect to parts, 30 parts by weight or less is preferable, 20 parts by weight or less is more preferable, and 10 parts by weight or less is particularly preferable.

The method for preparing the crosslinkable rubber composition of the present embodiment is not particularly limited, but a crosslinker and other compounding agents are added to the nitrile copolymer rubber composition obtained by the above-mentioned method to roll or roll. It may be kneaded with a kneader such as a rubbery mixer or a kneader.

In this case, the blending order is not particularly limited, but after sufficiently mixing the components that are difficult to react or decompose by heat, the components that are easily decomposed by heat (crosslinking agent, crosslinking accelerator, etc.) do not decompose. It may be mixed for a short time below the temperature.

The uncrosslinked rubber product of the present embodiment thus obtained is excellent in molding processability, and the crosslinked rubber product obtained from this uncrosslinked rubber product has strength characteristics, oil resistance, and ozone resistance. It is excellent.

<Rubber crosslinked product>
The rubber crosslinked product according to the present embodiment is obtained by cross-linking the crosslinkable rubber composition of the present embodiment described above.

When the crosslinkable rubber composition is crosslinked, it is molded by a molding machine corresponding to the shape of the molded product (rubber crosslinked product) to be manufactured, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and then crosslinked. The shape of the crosslinked product is fixed by reacting. When cross-linking, it may be cross-linked after being molded in advance, or may be cross-linked at the same time as molding. The molding temperature is usually 10 ° C. or higher, preferably 25 ° C. or higher, and usually 200 ° C. or lower, preferably 120 ° C. or lower. The crosslinking temperature is usually 100 ° C. or higher, preferably 130 ° C. or higher, and usually 200 ° C. or lower, preferably 190 ° C. or lower. The cross-linking time is usually 1 minute or more, preferably 2 minutes or more, and usually 24 hours or less, preferably 1 hour or less.

Depending on the shape, size, etc. of the rubber crosslinked product, even if the surface is crosslinked, it may not be sufficiently crosslinked to the inside. Therefore, the rubber crosslinked product may be further heated for secondary crosslinking.

The rubber crosslinked product of the present embodiment thus obtained is excellent in molding processability as an uncrosslinked rubber product, and can be obtained by using the above-described nitrile rubber composition and crosslinkable rubber composition of the present embodiment. Because it is a product, it has excellent strength characteristics, oil resistance, and ozone resistance.

Therefore, the rubber cross-linked product of the present embodiment includes sealing members such as packings, gaskets, O-rings, and oil seals; hoses such as oil hoses, fuel hoses, inlet hoses, gas hoses, brake hoses, and refrigerant hoses; diaphragms; accumulators. It is suitable for Prada; boots; etc., and is more preferably used as a fuel hose.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Unless otherwise specified, "parts" are based on weight. The test or evaluation method for physical properties and properties is as follows.

[Methyl ethyl ketone insoluble amount (MEK insoluble content)]
0.2 g of nitrile copolymer rubber (nitrile group-containing polymer) is placed in an 80-mesh wire net, and this is immersed in 50 ml of methyl ethyl ketone (hereinafter referred to as MEK) at room temperature for 24 hours, and then the wire net is taken out and at room temperature for 10 minutes. It was dried. Then, the polymer remaining on the 80-mesh wire mesh was weighed, and the MEK insoluble matter was measured from the weight. The MEK insoluble content (%) was calculated by the following formula.
MEK insoluble matter (%) = (CA) / (BA) × 100
A: Weight of wire mesh B: Weight of (sample before MEK immersion + wire mesh) C: Weight of (sample after MEK immersion and drying + wire mesh)

[Moony Viscosity (Polymer Mooney)]
The Mooney viscosity (polymer Mooney) of the nitrile copolymer rubber was measured according to JIS K6300 (unit: [ML1 + 4, 100 ° C.]).

[Minimum Mooney Viscosity (125 ° C)]
For the crosslinkable rubber composition, the Mooney viscosity-time curve at 125 ° C. was measured according to the Mooney viscosity test of JIS K6300-1, and the minimum Mooney viscosity (125 ° C.) was measured. The result of the lowest Mooney viscosity (125 ° C.) was used as an index of the deformability of the crosslinkable rubber composition. When the minimum Mooney viscosity (125 ° C.) was 33 or more, the shape retention during molding was good, and when it was less than 33, the shape retention during molding was inferior.

[Strength characteristics (100% tensile stress of uncrosslinked and crosslinked products)]
The crosslinkable rubber composition was placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and press-molded at 100 ° C. for 2 minutes while pressurizing, and then press-molded for 30 minutes while circulating cooling water at room temperature to form a sheet. An uncrosslinked rubber product was obtained. Further, the crosslinkable rubber composition was placed in a mold having a length of 15 cm, a width of 15 cm and a depth of 0.2 cm, and press-molded at 160 ° C. for 20 minutes while applying pressure to obtain a rubber crosslinked product. Using the obtained sheet-shaped uncrosslinked rubber and crosslinked rubber according to JIS K6251, using a test piece punched out in a dumbbell shape No. 3, 100% tension of the uncrosslinked rubber and the crosslinked rubber as normal physical properties. The stress (MPa) was measured. In the 100% tensile stress of the uncrosslinked rubber product, it was evaluated that the strength characteristics were excellent at 2.0 MPa or more, and that the strength characteristics were inferior at less than 2.0 MPa. Further, in the 100% tensile stress of the crosslinked rubber product, it was evaluated that the strength characteristics were excellent at 4.6 MPa or more, and that the strength characteristics were inferior at less than 4.6 MPa.

[Fuel resistance oil immersion test (toluene / isooctane = 50/50)]
A test piece obtained by cross-linking a cross-linking rubber composition similar to the cross-linking rubber composition used for the evaluation of the above normal physical properties and punching a rubber cross-linked product into a size of 30 mm × 20 mm × 2 mm was obtained by toluene / isooctane = 50/50. A fuel oil immersion test was carried out by immersing in fuel oil (Fuel-C) of (volume ratio) at 40 ° C. for 48 hours. In the fuel oil resistance test, the volume swelling degree ΔV (unit:%) after immersion was calculated according to the following formula.
Volume after immersion ΔV (unit:%) = ([Volume after oil immersion-Volume before oil immersion] / Volume before oil immersion) × 100
The closer the volume swelling degree ΔV after immersion was to 0%, the better the oil resistance was evaluated, and when the ΔV was 25% or more, the poor oil resistance was evaluated.

[Static ozone deterioration test (ozone resistance)]
Using the same sheet-shaped rubber crosslinked product used for the evaluation of the fuel oil resistance immersion test, the state after 120 hours was evaluated under the conditions of 40 ° C., ozone concentration of 50 pphm, and 30% elongation according to JIS K6259. .. The crack evaluation method was in accordance with the crack state evaluation method described in JIS K6257-1, and those in which cracks could not be observed with a 10x magnifying glass were represented by NC. When the result of the static ozone deterioration test was NC, it was evaluated as having excellent ozone resistance, and in other cases, it was evaluated as being inferior in ozone resistance.

[Production Example 1] (Production of nitrile copolymer rubber (A-1))
The reaction vessel was charged with 240 parts of water, 33 parts of acrylonitrile, 1 part of trimethylolpropane trimethacrylate, and 2.5 parts of sodium dodecylbenzenesulfonate (emulsifier), and the temperature was adjusted to 5 ° C. Then, after depressurizing the gas phase and sufficiently degassing, 66 parts of 1,3-butadiene, 0.04 part of p-menthan hydroperoxide as a polymerization initiator, 0.02 part of ethylenediaminetetraacetate, and sulfuric acid No. 1 0.006 parts of monoiron (7-hydrate), 0.06 parts of sodium formaldehyde sulfoxylate, and 1 part of t-dodecyl mercaptan, which is a chain transfer agent, were added to initiate the first stage reaction of emulsion polymerization. Then, when the polymerization conversion rate with respect to all the charged monomers reached 90% by weight, 0.3 part of hydroxylamine sulfate and 0.2 part of potassium hydroxide were added to stop the polymerization reaction. After the reaction was stopped, the contents of the reaction vessel were heated to 70 ° C., and the unreacted monomer was recovered by steam distillation under reduced pressure to recover the unreacted monomer to the latex (solid content 26 weight) of the nitrile copolymer rubber (A-1). %) Was obtained. Next, twice the volume of methanol was added to the obtained latex to solidify it, and then vacuum dried at 60 ° C. for 12 hours to obtain a nitrile copolymer rubber (A-1). ¹ As a result of measuring the composition of each monomer unit of the obtained nitrile copolymer rubber (A-1) by H-NMR, the acrylonitrile unit (AN amount) was 33.5% by weight and 1,3-butadiene unit. It was 65.5% by weight and 1% by weight of trimethylpropantrimethacrylate. The amount of methyl ethyl ketone insoluble (MEK insoluble) was 81%, and the polymer Mooney viscosity [ML1 + 4, 100 ° C.] was 78.

[Production Example 2] (Production of nitrile copolymer rubber (A-2))
In the first-stage reaction of emulsification polymerization, the nitrile copolymer rubber was the same as in Production Example 1 except that trimethylpropantrimethacrylate was not used in the preparation and the addition amount of 1,3-butadiene was changed to 67 parts. The latex (solid content 26% by weight) of (A-2) and the nitrile copolymer rubber (A-2) were obtained. Then, from the obtained latex, a nitrile copolymer rubber (A-2) was obtained in the same manner as in Production Example 1. As a result of measuring the composition of each monomer unit of the obtained nitrile copolymer rubber (A-2) in the same manner as in Production Example 1, acrylonitrile unit (AN amount) was 33.5% by weight, 1,3-. The butadiene unit was 66.5% by weight. The amount of methyl ethyl ketone insoluble (MEK insoluble) was 0%, and the polymer Mooney viscosity [ML1 + 4, 100 ° C.] was 46.

[Production Example 3] (Production of nitrile copolymer rubber (B-1))
240 parts of water, 75.7 parts of acrylonitrile and 2.5 parts of sodium dodecylbenzenesulfonate (emulsifier) were charged in the reaction vessel, and the temperature was adjusted to 5 ° C. Then, after depressurizing the gas phase and sufficiently degassing, 22 parts of 1,3-butadiene, 0.06 part of p-menthan hydroperoxide as a polymerization initiator, 0.02 part of ethylenediaminetetraacetate, and sulfuric acid No. 1 0.006 parts of monoiron (7-hydrate), 0.06 parts of sodium formaldehyde sulfoxylate, and 1 part of t-dodecyl mercaptan, which is a chain transfer agent, were added to initiate the first stage reaction of emulsion polymerization. After the start of the reaction, when the polymerization conversion rates with respect to the charged monomer reached 42% by weight and 60% by weight, respectively, 12 parts and 12 parts of 1,3-butadiene were added to the reaction vessel, respectively, and 2 parts were added. The polymerization reaction of the first step and the third step was carried out. Then, when the polymerization conversion rate with respect to all the charged monomers reached 75% by weight, 0.3 part of hydroxylamine sulfate and 0.2 part of potassium hydroxide were added to stop the polymerization reaction. After the reaction was stopped, the contents of the reaction vessel were heated to 70 ° C., and the unreacted monomer was recovered by steam distillation under reduced pressure to recover the unreacted monomer to the latex (solid content 24 weight) of the nitrile copolymer rubber (B-1). %) Was obtained. Next, a part of the obtained latex was sampled, coagulated with a large amount of methanol, filtered, and dried to obtain a nitrile copolymer rubber (B-1). As a result of measuring the composition of each monomer unit of the obtained nitrile copolymer rubber (B-1) in the same manner as in Production Example 1, acrylonitrile unit (AN amount) was 50% by weight and 1,3-butadiene unit. The amount of methyl ethyl ketone insoluble (MEK insoluble) was 0%, and the polymer Mooney viscosity [ML1 + 4, 100 ° C.] was 75.

[Production Example 4] (Production of nitrile copolymer rubber (B-2))
In the first-stage reaction of emulsion polymerization, the amount of acrylonitrile charged was 44 parts, the amount of 1,3-butadiene added was 56 parts without using trimethylpropantrimethacrylate, and the polymerization was carried out on all the charged monomers. A nitrile copolymer rubber (B-2) was obtained in the same manner as in Production Example 1 except that the polymerization was stopped when the conversion rate reached 92 weight. Next, as a result of measuring the composition of each monomer unit of the obtained nitrile copolymer rubber (B-2) in the same manner as in Production Example 1, the acrylonitrile unit (AN amount) was 40.5% by weight, 1,3. -Butadiene unit was 59.5% by weight. The amount of methyl ethyl ketone insoluble (MEK insoluble) was 0%, and the polymer Mooney viscosity [ML1 + 4, 100 ° C.] was 80.

[Example 1]
10 parts of the nitrile copolymer rubber (A-1) obtained in Production Example 1, 42 parts of the nitrile copolymer rubber (B-1) obtained in Production Example 3, and the nitriles obtained in Production Example 4. 18 parts of polymer rubber (B-2), 30 parts of vinyl chloride resin (average polymerization degree 1700) (trade name "TK-1700E", manufactured by Shin-Etsu Chemical Industry Co., Ltd.), di (butoxyethoxyethyl) adipate (trade name) "Adecasezer RS-107", manufactured by ADEKA, plasticizer, "Adecasezer" is a registered trademark, the same applies hereinafter) 5 parts) is added and kneaded at 175 ° C with a Banbury mixer to achieve nitrile co-weight. A coalesced rubber composition was obtained. Next, in the nitrile copolymer rubber composition obtained above, 45 parts of FEF carbon (trade name "Seast SO", manufactured by Tokai Carbon Co., Ltd., filler, "Seast" is a registered trademark), 5 parts of zinc oxide, A rubber composition was obtained by adding 25 parts of di (butoxyethoxyethyl) adipate (plasticizer) and kneading at 140 ° C. with a Banbury mixer. Next, the obtained rubber composition was wound around a roll heated to 50 ° C., 0.3 parts of 325 mesh sulfur (crosslinking agent), 1.5 parts of di-2-benzothiazolyl disulfide (crosslinking accelerator), And 1.5 parts of tetramethylthiuram disulfide (crosslinking accelerator) were added and kneaded with a roll to obtain a crosslinkable rubber composition. Then, using the obtained crosslinkable rubber composition, the minimum Mooney viscosity (125 ° C.), normal physical characteristics (100% tensile stress), and using the rubber crosslinked product obtained by the above method, normal physical characteristics ( 100% tensile stress), fuel oil immersion test, and static ozone deterioration test were each tested and evaluated. The results are shown in Table 1. In Example 1, the nitrile copolymer rubber (A-1) was designated as the nitrile copolymer rubber A, and the combination of the nitrile copolymer rubber (B-1) and the nitrile copolymer rubber (B-2) was used. When the nitrile copolymer rubber B was used, the content (AN content) of acrylonitrile was 45.2% by weight based on the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 2]
The amount of the nitrile copolymer rubber (A-1) obtained in Production Example 1 was 20 parts, and the amount of the nitrile copolymer rubber (B-1) obtained in Production Example 3 was 50 parts. A nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained in the same manner as in Example 1 except that the nitrile copolymer rubber (B-2) obtained in Production Example 4 was not used. Each test and evaluation was conducted. The results are shown in Table 1. In Example 2, when the nitrile copolymer rubber (A-1) is the nitrile copolymer rubber A and the nitrile copolymer rubber (B-1) is the nitrile copolymer rubber B, the nitrile copolymer weight is used. The content of acrylonitrile (AN content) was 45.3% by weight based on the total of the combined rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 3]
Except that the amount of the nitrile copolymer rubber (A-1) used was 30 parts and the amount of the nitrile copolymer rubber (B-1) obtained in Production Example 3 was 40 parts, the same as in Example 2. Similarly, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Example 3, similarly to Example 2, when the nitrile copolymer rubber A and the nitrile copolymer rubber B are used, the total amount of the nitrile copolymer rubber A and the nitrile copolymer rubber B is acrylonitrile. The content (AN amount) of was 42.9% by weight. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 4]
Same as Example 1 except that 30 parts of vinyl chloride resin (average polymerization degree 1000) (trade name "TK-1000", manufactured by Shinetsu Chemical Industry Co., Ltd.) was used instead of vinyl chloride resin (average degree of polymerization 1700). , A nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Example 4, similarly to Example 1, when the nitrile copolymer rubber A and the nitrile copolymer rubber B are used, the total amount of the nitrile copolymer rubber A and the nitrile copolymer rubber B is acrylonitrile. The content (AN amount) of was 45.2% by weight. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 5]
The amount of the nitrile copolymer rubber (A-1) obtained in Production Example 1 was 8.6 parts, and the amount of the nitrile copolymer rubber (B-1) obtained in Production Example 3 was 36 parts. Except that the amount of the nitrile copolymer rubber (B-2) obtained in Production Example 4 was 15.4 parts and the amount of vinyl chloride resin (average polymerization degree 1700) was 40 parts. In the same manner as in Example 1, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Example 5, similarly to Example 1, when the nitrile copolymer rubber A and the nitrile copolymer rubber B were used, the total amount of the nitrile copolymer rubber A and the nitrile copolymer rubber B was acrylonitrile. The content (AN amount) of was 45.2% by weight. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 67 parts.

[Example 6]
Except that the nitrile copolymer rubber (B-1) obtained in Production Example 3 was not used and the amount of the nitrile copolymer rubber (B-2) obtained in Production Example 4 was 60 parts. In the same manner as in Example 1, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Example 6, when the nitrile copolymer rubber (A-1) is the nitrile copolymer rubber A and the nitrile copolymer rubber (B-2) is the nitrile copolymer rubber B, the nitrile copolymer weight is used. The content of acrylonitrile (AN content) was 39.5% by weight based on the total of the combined rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 7]
Similar to Example 2, the nitrile copolymer weight was the same as in Example 2, except that 20 parts of the nitrile copolymer rubber (A-2) obtained in Production Example 2 was used instead of the nitrile copolymer rubber (A-1). A combined rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Example 7, when the nitrile copolymer rubber (A-2) is the nitrile copolymer rubber A and the nitrile copolymer rubber (B-1) is the nitrile copolymer rubber B, the nitrile copolymer weight is used. The content of acrylonitrile (AN content) was 45.3% by weight based on the total of the combined rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 1]
The amount of the nitrile copolymer rubber (A-1) obtained in Production Example 1 was 11.4 parts, and the amount of the nitrile copolymer rubber (B-1) obtained in Production Example 3 was 48 parts. Except that the amount of the nitrile copolymer rubber (B-2) obtained in Production Example 4 was 20.6 parts and the amount of vinyl chloride resin (average polymerization degree 1700) was 20 parts. In the same manner as in Example 1, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Comparative Example 1, similarly to Example 1, when the nitrile copolymer rubber A and the nitrile copolymer rubber B were used, the total amount of the nitrile copolymer rubber A and the nitrile copolymer rubber B was acrylonitrile. The content (AN amount) of was 45.2% by weight. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 25 parts.

[Comparative Example 2]
Same as Example 4 except that 30 parts of vinyl chloride resin (average degree of polymerization 700) (trade name "TK-700", manufactured by Shinetsu Chemical Industry Co., Ltd.) was used instead of vinyl chloride resin (average degree of polymerization 1700). , A nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Comparative Example 2, similarly to Example 1, when the nitrile copolymer rubber A and the nitrile copolymer rubber B were used, the total amount of the nitrile copolymer rubber A and the nitrile copolymer rubber B was acrylonitrile. The content (AN amount) of was 45.2% by weight. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 3]
This was carried out except that the amount of the nitrile copolymer rubber (A-2) obtained in Production Example 2 was 60 parts instead of the nitrile copolymer rubber (B-2) obtained in Production Example 4. In the same manner as in Example 6, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Comparative Example 3, when the nitrile copolymer rubber (A-1) and the nitrile copolymer rubber (A-2) were used as the nitrile copolymer rubber A and the nitrile copolymer rubber B was not used, The content of acrylonitrile (AN content) was 33.5% by weight based on the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 4]
Except that the nitrile copolymer rubber (A-1) obtained in Production Example 1 was not used and the amount of the nitrile copolymer rubber (A-2) obtained in Production Example 2 was 70 parts. Similar to Comparative Example 3, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was carried out in the same manner. The results are shown in Table 1. In Comparative Example 4, when the nitrile copolymer rubber (A-2) was used as the nitrile copolymer rubber A and the nitrile copolymer rubber B was not used, the nitrile copolymer rubber A and the nitrile copolymer were used. The content of acrylonitrile (AN content) was 33.5% by weight based on the total amount of rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 5]
The nitrile copolymer rubber (A-1) obtained in Production Example 1 was not used, and the amount of the nitrile copolymer rubber (B-1) obtained in Production Example 3 was 40 parts, and Production Example 4 was used. A nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained in the same manner as in Example 1 except that the amount of the nitrile copolymer rubber (B-2) obtained in 1 was 30 parts. Each test and evaluation was conducted. The results are shown in Table 1. In Comparative Example 5, when the nitrile copolymer rubber A was not used and the nitrile copolymer rubber (B-1) and the nitrile copolymer rubber (B-2) were used as the nitrile copolymer rubber B, The content of acrylonitrile (AN content) was 45.9% by weight based on the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B. The compounding ratio of the vinyl chloride resin to a total of 100 parts of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

From Table 1, 40% by weight of the nitrile copolymer rubber (A) containing less than 40% by weight of the α, β-ethylenically unsaturated nitrile monomer unit and 40% by weight of the α, β-ethylenically unsaturated nitrile monomer unit. A nitrile copolymer rubber (B) containing% or more and a vinyl chloride resin (C) having an average degree of polymerization of 800 or more, and the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) Excellent molding processability of the uncrosslinked rubber obtained by the nitrile copolymer rubber composition in which the content ratio of the vinyl chloride resin (C) is 35 parts by weight or more with respect to 100 parts by weight in total, and the strength characteristics of the crosslinked rubber. It was excellent in oil resistance and ozone resistance (Examples 1 to 7).

On the other hand, the nitrile copolymer rubber (A) containing less than 40% by weight of the α, β-ethylenically unsaturated nitrile monomer unit and 40% by weight or more of the α, β-ethylenically unsaturated nitrile monomer unit. The nitrile copolymer rubber (B) contained and the vinyl chloride resin (C) having an average degree of polymerization of 800 or more are contained, and the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) is 100. A nitrile copolymer rubber composition in which the content ratio of the vinyl chloride resin (C) with respect to parts by weight does not satisfy the condition of 35 parts by weight or more has the molding processability of the obtained uncrosslinked rubber, the strength characteristics of the crosslinked rubber, and the like. It was inferior in at least one of oil resistance and ozone resistance (Comparative Examples 1 to 5).

Although the embodiments of the present invention have been described above with reference to examples, the present invention is not limited to the specific embodiments and examples, and various within the scope of the invention described in the claims. Can be transformed and changed.

This international application claims priority based on Japanese Patent Application No. 2018-032354 filed on February 26, 2018, the entire contents of which are incorporated herein by reference.

Claims (7)

Nitrile copolymer rubber (A) containing less than 40% by weight of α, β-ethylenically unsaturated nitrile monomer unit, and
Nitrile copolymer rubber (B) containing 40% by weight or more of α, β-ethylenically unsaturated nitrile monomer unit, and
Contains a vinyl chloride resin (C) having an average degree of polymerization of 800 or more,
A nitrile copolymer rubber composition in which the content ratio of the vinyl chloride resin (C) is 35 parts by weight or more with respect to a total of 100 parts by weight of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). .. The nitrile copolymer rubber composition according to claim 1, wherein the methyl ethyl ketone (MEK) insoluble content of the nitrile copolymer rubber (A) is 60% or more. The invention according to claim 1 or 2, wherein the total amount of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) is 35% by weight or more of α, β-ethylenic unsaturated nitrile monomer unit. Nitrile copolymer rubber composition. The nitrile copolymer rubber composition according to any one of claims 1 to 3, wherein the vinyl chloride resin (C) has an average degree of polymerization of 1300 or more. A crosslinkable rubber composition obtained by blending a crosslinking agent with the nitrile copolymer rubber composition according to any one of claims 1 to 4. A rubber crosslinked product obtained by crosslinking the crosslinkable rubber composition according to claim 5. A hose using the nitrile copolymer rubber composition according to any one of claims 1 to 4.