WO2019163482A1

WO2019163482A1 - Nitrile copolymer rubber composition, crosslinkable rubber composition, crosslinked rubber object, and hose

Info

Publication number: WO2019163482A1
Application number: PCT/JP2019/003618
Authority: WO
Inventors: 弘康永森; 杉山　学
Original assignee: 日本ゼオン株式会社
Priority date: 2018-02-26
Filing date: 2019-02-01
Publication date: 2019-08-29
Also published as: JPWO2019163482A1; JP7136180B2

Abstract

A nitrile copolymer rubber composition which comprises a nitrile copolymer rubber (A) containing units of an α,β-ethylenically unsaturated nitrile monomer in an amount less than 40 wt%, a nitrile copolymer rubber (B) containing units of an α,β-ethylenically unsaturated nitrile monomer in an amount of 40 wt% or larger, and a vinyl chloride resin (C) having an average degree of polymerization of 800 or higher, wherein the content of the vinyl chloride resin (C) is 35 parts by weight or higher per 100 parts by weight of the sum of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B).

Description

Nitrile copolymer rubber composition, crosslinkable rubber composition, cross-linked rubber, and hose

The present invention relates to a nitrile copolymer rubber composition, a crosslinkable rubber composition, a rubber cross-linked product, and a hose.

Conventionally, rubber (nitrile copolymer rubber) containing an α, β-ethylenically unsaturated nitrile monomer unit and a conjugated diene monomer unit is a rubber having excellent oil resistance, such as a rubber for a fuel hose. Used in products. In addition to oil resistance, such rubber products are required to have advanced performance 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.

JP 2003-306580 A

However, in the conventional nitrile copolymer rubber composition, there is a possibility that the shape at the time of molding cannot be maintained, and there is a problem that a crosslinked rubber product having a desired shape cannot be obtained if it is crosslinked in that state (for example, A cylindrical rubber uncrosslinked product is plastically deformed during molding or standing, and the cylindrical shape is crushed). Thus, conventional nitrile copolymer rubber compositions have insufficient rubber crosslinkable rubber (or crosslinkable rubber composition) moldability and rubber crosslinks with 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 product and excellent in strength properties, oil resistance and ozone resistance of the rubber crosslinked product.

In order to solve the above-described problems, one embodiment of the present invention provides a nitrile copolymer rubber (A) containing less than 40% by weight of an α, β-ethylenically unsaturated nitrile monomer unit, and an α, β-ethylenic property. A nitrile copolymer rubber (B) containing 40% by weight or more of an unsaturated nitrile monomer unit 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) in a total of 100 parts by weight, the content ratio of the vinyl chloride resin (C) is 35 parts by weight or more.

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

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

<Nitrile copolymer rubber composition>
A nitrile copolymer rubber composition according to an embodiment of the present invention includes a nitrile copolymer rubber (A) containing less than 40% by weight of an α, β-ethylenically unsaturated nitrile monomer unit, an 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, and a nitrile copolymer rubber ( The content ratio of the vinyl chloride resin (C) is 35 parts by weight or more based on 100 parts by weight of the total of A) and the nitrile copolymer rubber (B).

<Nitrile copolymer rubber (A)>
The nitrile copolymer rubber (A) used in the present embodiment is a rubber containing at least an α, β-ethylenically unsaturated nitrile monomer unit in a proportion of less than 40% by weight. In the present specification, an α, β-ethylenically unsaturated nitrile monomer is a compound having a nitrile group and having a double bond between the α-position carbon and the β-position 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 the total 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 resulting rubber cross-linked product and the strength characteristics of the rubber cross-linked product may be lowered. 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 oil resistance of the obtained rubber cross-linked 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 nitrile copolymer rubbers (A) may be mixed and used. When a plurality of nitrile copolymer rubbers (A) are mixed, the content ratio of α, β-ethylenically unsaturated nitrile monomer units in the entire rubber mixture having different monomer compositions is within the above range. do it. For example, as the nitrile copolymer rubber (A), a rubber (α) containing 25% by weight of an α, β-ethylenically unsaturated nitrile monomer unit, a rubber (β) containing 35% by weight, Are mixed at a ratio 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). The rubber (β) is 30% by weight. Hereinafter, the same applies to diene monomer units or α-olefin monomer units.

The α, β-ethylenically unsaturated nitrile monomer forming the α, β-ethylenically unsaturated nitrile monomer unit is not particularly limited, and examples thereof include 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 individually by 1 type or in combination of multiple types.

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

The methyl ethyl ketone insoluble content (MEK insoluble content) is the amount of the 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 matter increases.

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

The nitrile copolymer rubber (A) used in the present embodiment also contains a diene monomer unit or an α-olefin monomer unit so that the resulting rubber cross-linked product has rubber elasticity. It is preferable.

Diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and the like, preferably conjugated dienes having 4 or more carbon atoms; And non-conjugated dienes having 5 to 12 carbon atoms, such as 4-pentadiene, 1,4-hexadiene, vinylnorbornene, and dicyclopentadiene. Of these, conjugated dienes are 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 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. More preferably, it is 64% by weight or more, preferably 78% by weight or less, more preferably 74% by weight or less, and further preferably 70% by weight or less. By setting the content ratio of the diene monomer unit or α-olefin monomer unit in the above range, the crosslinkable rubber composition obtained is excellent in molding processability, and the strength properties, oil resistance, Rubber elasticity can be appropriately improved while making it excellent in ozone resistance.

Further, the nitrile copolymer rubber (A) used in the present embodiment includes these α, β-ethylenically unsaturated nitrile monomer units, diene monomer units, and α-olefin monomer units. Other monomer units that are copolymerizable with the monomer that forms the monomer unit may be contained. The content ratio of such other monomer units is preferably 30% by weight or less, more preferably 20% by weight or less, and still more preferably 10% by weight or less based on the total monomer units.

Examples of such other copolymerizable monomers include aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethyl styrene, 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-ethylenically unsaturated carboxylic acids such as methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, fumaric anhydride and the like; methyl (meth) acrylate, (meth) Ethyl acrylate, (meth) acrylic acid butyrate Α, β-ethylenically unsaturated monocarboxylic acid alkyl esters such as 2-ethylhexyl (meth) acrylate; monoethyl maleate, diethyl maleate, mono n-butyl maleate, dibutyl maleate, monoethyl fumarate, fumaric acid Α, β-ethylenic unsaturation such as diethyl, mono n-butyl fumarate, dibutyl fumarate, monocyclohexyl fumarate, dicyclohexyl fumarate, monoethyl itaconate, diethyl itaconate, mono n-butyl itaconate, dibutyl itaconate Monoesters and diesters of polycarboxylic acids; alkoxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, butoxyethyl (meth) acrylate; (Meta) Acry Hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl oxalate and 3-hydroxypropyl (meth) acrylate; divinyl compounds such as divinylbenzene; ethylene di (meth) acrylate, diethylene glycol di (meta In addition to polyfunctional ethylenically unsaturated monomers such as) acrylates, di (meth) acrylates such as ethylene glycol di (meth) acrylate; trimethacrylates such as trimethylolpropane tri (meth) acrylate; And self-crosslinking compounds such as N-methylol (meth) acrylamide and N, N′-dimethylol (meth) acrylamide;

In the present specification, “(meth) acrylic acid” means both “acrylic acid” and “methacrylic acid”. Thus, for example, methyl (meth) acrylate refers to methyl acrylate and / or methyl methacrylate.

Among these, it is preferable to copolymerize a monomer having at least two polymerizable unsaturated groups. Among them, polyfunctional ethylene such as divinyl compound; di (meth) acrylic acid ester; trimethacrylic acid ester; It is preferable to copolymerize a polymerizable unsaturated monomer, and it is particularly preferable to copolymerize trimethylolpropane tri (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. . In addition, the amount insoluble in methyl ethyl ketone can be adjusted by copolymerization thereof.

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 resulting rubber cross-linked product may be lowered. On the other hand, if the polymer Mooney viscosity is too high, moldability may be reduced. 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 monomers are copolymerized and, if necessary, the carbon-carbon double in the resulting copolymer. It can be produced by hydrogenating the bonds. The polymerization method is not particularly limited and may be a known emulsion polymerization method or solution polymerization method. From the viewpoint of industrial productivity, the emulsion polymerization method is preferable. In emulsion polymerization, in addition to an emulsifier, a polymerization initiator, and a molecular weight modifier, a commonly used polymerization auxiliary material can be used.

Although it does not specifically limit as an emulsifier, For example, Nonionic emulsifiers, 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, anionic emulsifiers such as higher alcohol sulfates and alkylsulfosuccinates; sulfoesters of α, β-unsaturated carboxylic acids, α , Β-unsaturated carboxylic acid sulfate esters, sulfoalkyl aryl ethers and other copolymerizable emulsifiers. The addition amount of the emulsifier is preferably 0.1 parts by weight or more, more preferably 0.5 parts 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. The amount is preferably 5 parts by weight or less.

The polymerization initiator is not particularly limited as long as it is a radical initiator, but inorganic peroxides 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 and t-butylperoxyisobutyrate; azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, etc. Azo Compounds; and the like. These polymerization initiators can be used alone or in combination of two or more. As the polymerization initiator, an inorganic or organic peroxide is preferable. When a peroxide is used as the polymerization initiator, it can be used as a redox polymerization initiator in combination with a reducing agent such as sodium bisulfite or ferrous sulfate.

The addition amount of the polymerization initiator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and further preferably 0.1 parts by weight or more with respect to 100 parts by weight of the monomer used for the polymerization. And preferably 2 parts by weight or less, more preferably 1.5 parts by weight or less, and still more preferably 1.0 parts by weight or less.

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

In the emulsion polymerization, polymerization auxiliary materials such as a stabilizer, a dispersant, a pH adjuster, an oxygen scavenger, and a particle size adjuster can be used as necessary. In using these, neither the kind nor the usage-amount is specifically limited.

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

In the case of obtaining a crosslinkable rubber composition to be described later 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. In addition to the nitrile copolymer rubber (A) to be included in the nitrile copolymer rubber composition, a nitrile copolymer rubber (A) is added together with a crosslinking agent when obtaining a crosslinkable rubber composition to be described later. It is good also as an aspect which adds.

<Nitrile copolymer rubber (B)>
Moreover, the nitrile copolymer rubber composition of this embodiment contains a nitrile copolymer rubber (B) in addition to the nitrile copolymer rubber (A) described above. The nitrile copolymer rubber (B) used in the present embodiment is a rubber containing at least an 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 units. More preferably, it is 47% by weight or more. When the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit is too low, the molding processability of the resulting rubber uncrosslinked product, the strength properties of the rubber crosslinked product, and the oil resistance tend to be lowered. On the other hand, the upper limit of the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile copolymer rubber (B) of the nitrile copolymer rubber (B) is not particularly limited. 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 of the nitrile copolymer rubber (B) is preferably 1900 parts by weight or less, more preferably 900 parts by weight or less, with respect to 100 parts by weight of the nitrile copolymer rubber (A).

In the present embodiment, as the nitrile copolymer rubber (B), one kind of rubber may be used, but the nitrile copolymer rubber containing 40% by weight or more of α, β-ethylenically unsaturated nitrile monomer unit. A plurality of types of polymer rubber (B) may be mixed and used. When a plurality of nitrile copolymer rubbers (B) are mixed, the content ratio of α, β-ethylenically unsaturated nitrile monomer units in the entire rubber mixture 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 units of 55% by weight, a rubber (β) having a content of 45% by weight, Are mixed at a ratio 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). The rubber (β) is 50% by weight. Hereinafter, the same applies to diene monomer units or α-olefin monomer units.

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

Further, the nitrile copolymer rubber (B) used in the present embodiment also contains a diene monomer unit or an α-olefin monomer unit so that the obtained rubber cross-linked product has rubber elasticity. It is preferable. As the diene monomer unit or α-olefin monomer unit, those similar to the nitrile copolymer rubber (A) described above can be used, and 1,3-butadiene is preferred.

The content ratio of the diene monomer unit or 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. More preferably, it is 40% by weight or more, particularly preferably 45% by weight or more, preferably 60% by weight or less, more preferably 55% by weight or less, and further preferably 53% by weight or less. By setting the content ratio of the diene monomer unit or α-olefin monomer unit in the above range, the resulting rubber uncrosslinked product is excellent in molding processability, and the resulting rubber crosslinked product has strength characteristics, oil resistance, Rubber elasticity can be appropriately improved while being excellent in ozone.

The nitrile copolymer rubber (B) used in the present embodiment is similar to the nitrile copolymer rubber (A) in that the α, β-ethylenically unsaturated nitrile monomer unit and the diene monomer unit or α In addition to the olefin monomer units, other monomer units copolymerizable with the monomers forming these monomer units may be contained. Further, the content ratio of other monomer units contained in such a nitrile copolymer rubber (B) is the same as that of the nitrile copolymer rubber (A) described above, Preferably it is 30 weight% or less, More preferably, it is 20 weight% or less, More preferably, it is 10 weight% or less.

Examples of other copolymerizable monomers contained in such a nitrile copolymer rubber (B) include, for example, styrene, α-methylstyrene, vinyltoluene and the like as in the nitrile copolymer rubber (A). Fluorine-containing vinyl compounds such as fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethyl styrene, vinyl pentafluorobenzoate, difluoroethylene, tetrafluoroethylene; 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 anhydride, etc. β-ethylenically unsaturated carboxylic acid and its anhydride; ) Α, β-ethylenically unsaturated monocarboxylic acid alkyl esters such as methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; monoethyl maleate, maleic acid Diethyl, mono n-butyl maleate, dibutyl maleate, monoethyl fumarate, diethyl fumarate, mono n-butyl fumarate, dibutyl fumarate, monocyclohexyl fumarate, dicyclohexyl fumarate, monoethyl itaconate, diethyl itaconate, itacon Monoesters and diesters of α, β-ethylenically unsaturated polyvalent carboxylic acids such as mono-n-butyl acid and dibutyl itaconate; methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, (meth) acrylic acid Α, β such as butoxyethyl -Alkoxyalkyl esters of ethylenically unsaturated carboxylic acids; hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate; divinylbenzene Divinyl compounds such as ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, di (meth) acrylates such as ethylene glycol di (meth) acrylate; trimethacrylic acid esters such as trimethylolpropane tri (meth) acrylate And other self-crosslinking compounds such as N-methylol (meth) acrylamide and N, N'-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 resulting rubber cross-linked product may be lowered. On the other hand, if the polymer Mooney viscosity is too high, moldability may be reduced. The Mooney viscosity of the nitrile copolymer rubber (B) can be measured, for example, according to JIS K6300.

The production method of the nitrile copolymer rubber (B) used in the present embodiment is not particularly limited, but the same production method as that of the nitrile copolymer rubber (A) described above can be used. Also in this case, it can be produced by hydrogenating a carbon-carbon double bond in the obtained copolymer, if necessary. The polymerization method is not particularly limited, and may be a known emulsion polymerization method or solution polymerization method as in the case of the nitrile copolymer rubber (A) described above. From the viewpoint of industrial productivity, the emulsion polymerization method may be used. Is preferred. In emulsion polymerization, in addition to the same emulsifier, polymerization initiator and molecular weight modifier as those of the nitrile copolymer rubber (A) described above, commonly used polymerization auxiliary materials can be used.

In the case of obtaining a crosslinkable rubber composition to be described later 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. In addition to the nitrile copolymer rubber (B) contained in the nitrile copolymer rubber composition, a nitrile copolymer rubber (B) is added together with a crosslinking agent when obtaining a crosslinkable rubber composition to be described later. It is good also as an aspect which adds.

Further, the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) preferably 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 total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) contains 35% by weight or more of an α, β-ethylenically unsaturated nitrile monomer unit. It means that 35% by weight or more of α, β-ethylenically unsaturated nitrile monomer unit is contained with respect to the total of (A) and nitrile copolymer rubber (B).

If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too low in the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B), molding of the resulting rubber uncrosslinked product There is a tendency for processability and strength properties of the rubber cross-linked product to decrease. On the other hand, although there is no upper limit of the content ratio, the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit is preferably 70% by weight from the viewpoint of the miscibility with other components and the cold resistance of the rubber crosslinked product. % Or less, more preferably 60% by weight or less, further preferably 55% by weight or less, and particularly preferably 50% by weight or less.

<Vinyl chloride resin (C)>
In addition to the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) described above, the nitrile copolymer rubber composition of the present embodiment comprises a vinyl chloride resin (C) having an average degree of polymerization of 800 or more. 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 thereof is in the range of 800 or more, but the content of the main constituent monomer unit is not particularly limited. Is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, still 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 resulting rubber cross-linked product is lowered. 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 the miscibility 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 defined 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 a copolymer obtained by copolymerizing other monomers copolymerizable with vinyl chloride in addition to the main constituent monomer vinyl chloride. . Examples of such other monomers include (meth) acrylic acid alkyl esters having an alkyl group of 1 to 20 carbon atoms; aromatic vinyl compounds such as styrene, vinyl toluene, and α-methyl styrene; acrylonitrile, 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, seeding 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 based on 100 parts by weight of the 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, more preferably 40 parts by weight or more. When there is too little content of a vinyl chloride resin (C), the processability of the rubber uncrosslinked product obtained and the strength characteristic of a rubber crosslinked product will 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 miscibility with the nitrile copolymer rubber (A) and / or the nitrile copolymer rubber (B). The amount 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.

The nitrile copolymer rubber composition of the present embodiment contains other compounding agents in addition to the nitrile copolymer rubber (A), the nitrile copolymer rubber (B) and the vinyl chloride resin (C) described above. You may contain. Examples of such other compounding agents include plasticizers and anti-aging stabilizers.

The compounding amount of these other compounding agents is not particularly limited as long as the purpose and effect of the present embodiment are not impaired, and an amount corresponding to the compounding purpose can be blended.

Specific examples of the plasticizer include ester compounds of adipic acid and ether-containing alcohols such as di (butoxyethyl) adipate and di (butoxyethoxyethyl) adipate; dibutoxyethyl azelate, Ester compounds of azelaic acid such as butoxyethoxyethyl) and ether bond-containing alcohols; ester compounds of sebacic acid such as dibutoxyethyl sebacate and di (butoxyethoxyethyl) sebacate and ether bond-containing alcohols; dibutoxy phthalate Ester compounds of phthalic acid such as ethyl and di (butoxyethoxyethyl) phthalate with alcohols containing ether bonds; isophthalic acid such as dibutoxyethyl isophthalate and di (butoxyethoxyethyl) isophthalate and ether bonds Ester compounds with cole; di- (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, dibutyl adipate, etc .; di- (2-ethylhexyl) azelate, diisooctyl azelate, azelain Dialkyl esters of azelaic acid such as di-n-hexyl acid; dialkyl esters of sebacic acid such as di-n-butyl sebacate, di- (2-ethylhexyl) sebacate; dibutyl phthalate, di-phthalate (2- Ethylhexyl), di-n-octyl phthalate, diisobutyl phthalate, diheptyl phthalate, diisodecyl phthalate, diundecyl phthalate, diisononyl phthalate, and the like; phthalic acids such as dicyclohexyl phthalate Cycloalkyl esters; Phthalic acid aryl esters such as diphenyl phthalate and butyl benzyl phthalate; Diphthalic acid dialkyl esters such as di- (2-ethylhexyl) isophthalate and diisooctyl isophthalate; Tetrahydrophthalic acid di- (2- Ethyl hexyl), tetrahydrophthalic acid dialkyl esters such as tetrahydrophthalic acid di-n-octyl, tetrahydrophthalic acid diisodecyl; trimellitic acid tri- (2-ethylhexyl), trimellitic acid tri-n-octyl, trimellitic acid triisodecyl, Trimellitic acid derivatives such as triisooctyl trimellitic acid, tri-n-hexyl trimellitic acid, triisononyl trimellitic acid, triisodecyl trimellitic acid; epoxidized soybean oil, epoxidized flax And epoxy plasticizers such as ni oil; phosphate ester plasticizers such as tricresyl phosphate; and the like. These can be used individually by 1 type or in combination of multiple types.

Among these, a dibasic acid such as adipic acid, azelaic acid, sebacic acid, and phthalic acid, and an ether bond-containing alcohol are used from the viewpoint that the resulting rubber cross-linked product can have better oil resistance. An ester compound is preferred, an ester compound of adipic acid and an ether bond-containing alcohol is more preferred, and di (butoxyethoxyethyl) adipate is particularly preferred.

The content of the plasticizer in the nitrile copolymer rubber composition of the present embodiment is preferably 1 with respect to a total of 100 parts by weight of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). Parts by weight or more, more preferably 2 parts by weight or more, further 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 60 parts by weight or less, particularly preferably 50 parts by weight or less.
By making content of a plasticizer into the said range, the addition effect can be improved more.

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

In addition, the mixing temperature at the time of mixing each component containing a nitrile copolymer rubber (A), a nitrile copolymer rubber (B), and a vinyl chloride resin (C) is not particularly limited, but is preferably a vinyl chloride resin. (C) It is temperature more than melting | fusing point, More preferably, it is more preferable to mix at the temperature 5 degreeC or more higher than the softening point of vinyl chloride resin (C), and it is more than the softening point of vinyl chloride resin (C). The temperature is 10 ° C. or higher. Specifically, the mixing is preferably performed at 160 ° C or higher, more preferably performed at 165 ° C or higher, and further preferably performed 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 increased, and thus the resulting rubber cross-linked product is more excellent in ozone resistance. Can be.

Alternatively, in the nitrile copolymer rubber composition of the present embodiment, each component including the nitrile copolymer rubber (A) and the vinyl chloride resin (C) can be mixed in an aqueous system. A latex of a nitrile copolymer rubber (A) and a nitrile copolymer rubber (B) obtained by emulsion polymerization are made into a latex vinyl chloride resin (C) produced by a conventionally known emulsion polymerization method or suspension polymerization method. ) Or other components (latex blend).

<Crosslinkable rubber composition>
The crosslinkable rubber composition according to the embodiment is obtained by blending a crosslinking agent with the nitrile copolymer rubber composition of the present embodiment described above. Examples of the crosslinking agent include a sulfur-based crosslinking agent and an organic peroxide crosslinking agent. Although these can be used individually by 1 type or in combination of multiple types, it is preferable to use a sulfur type crosslinking agent.

Sulfur-based cross-linking agents include powdered sulfur, sulfur white, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, etc .; sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, dibenzothiazyl disulfide, caprolactam disulfide And sulfur-containing compounds such as phosphorus-containing polysulfides and polymer polysulfides; sulfur-donating compounds such as tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, and 2- (4′-morpholinodithio) benzothiazole. These can be used individually by 1 type or in combination of multiple types.

Examples of organic peroxide crosslinking agents include dicumyl peroxide, cumene hydroperoxide, t-butylcumyl peroxide, p-menthane hydroperoxide, di-t-butyl peroxide, 1,3-bis (t-butylperoxyisopropyl) 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-butylperoxyhexyne-3, 1,1-di-t- Butylperoxy-3,5,5-trimethylcyclohexane, p-chlorobenzoyl peroxide, t-butylperoxy Isopropyl carbonate, t- butyl peroxybenzoate, and the like. These can be used individually by 1 type or in combination of multiple types.

The content of the crosslinking agent in the crosslinkable rubber composition of the present embodiment is a total of 100 of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) from the viewpoint of obtaining a good rubber cross-linked product. The amount is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, further preferably 0.3 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight or more. It is 6 parts by weight or less, more preferably 6 parts by weight or less.

In the case of using a sulfur-based crosslinking agent, crosslinking aids such as activated zinc white, zinc white and stearic acid; guanidine type, aldehyde-amine type, aldehyde-ammonia type, thiazole type, sulfenamide type, thiourea type, etc. These crosslinking accelerators can be used in combination. These crosslinking aids and crosslinking accelerators are used in an amount of preferably 0.1 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). It is a range.

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

Moreover, the crosslinkable rubber composition of the present embodiment may further contain a hydrocarbon wax. By further containing a hydrocarbon wax, the resulting rubber cross-linked product can be made more excellent in ozone resistance.

Examples of the hydrocarbon wax include polyolefin waxes such as polyethylene wax and polypropylene wax; Fischer-Tropsch wax; petroleum waxes such as paraffin wax and microstarin wax. Among these, Fischer-Tropsch 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 the same plasticizer 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 a total of 100 parts by weight of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B). More preferably, it is 5 parts by weight or more, more 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 making content of a plasticizer into the said range, the addition effect can be improved more. In addition, the content of the plasticizer in the crosslinkable rubber composition of the present embodiment is such that the total content of the plasticizer contained in the nitrile copolymer rubber composition of the present embodiment described above falls within the above range. Adjust it.

In addition, the crosslinkable rubber composition of the present embodiment has other compounding agents used for general rubber as necessary, for example, a crosslinking retarder, a reinforcing agent, a filler, a lubricant, an adhesive, a lubricant, You may mix | blend additives, such as a processing aid, a flame retardant, an antifungal agent, an antistatic agent, a coloring agent, and a coupling agent.

The filler is not particularly limited, and carbon-based materials such as carbon black and graphite can be used. Among 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), HAF- HS (N339), HAF-LS (N326), MAF, FEF (N550), SRF (N762, N774) and the like. Specific examples of thermal black include FT and MT (N990). 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; starch and polystyrene powder, etc. Examples thereof include powders such as organic powders; short fibers (the above-mentioned short fibers) such as glass fibers (milled fibers), carbon fibers, aramid fibers, and potassium titanate whiskers; silica and mica. Of these, silica is preferably used.

Examples of silica include natural silica such as quartz powder and silica powder; synthetic silica such as anhydrous silicic acid (silica gel, aerosil, etc.) and hydrous silicic acid. Among these, synthetic silica is preferable. 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 blending amount of the filler is not particularly limited, but is preferably 5 parts by weight or more, more preferably 10 parts by weight or more with respect to 100 parts by weight of the nitrile group-containing copolymer rubber from the viewpoint of improving tensile stress. More preferably, it is 15 parts by weight or more, preferably 200 parts by weight or less, more preferably 150 parts by weight or less, and still more preferably 100 parts by weight or less.

Furthermore, the crosslinkable rubber composition of the present embodiment may be blended with 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 inhibited. Good. As rubbers other than the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B), acrylic rubber, ethylene-acrylic acid copolymer rubber, fluorine rubber, styrene-butadiene copolymer rubber, polybutadiene rubber, ethylene -Propylene copolymer rubber, ethylene-propylene-diene terpolymer rubber, epichlorohydrin rubber, urethane rubber, chloroprene rubber, silicone rubber, fluorosilicone rubber, chlorosulfonated polyethylene rubber, natural rubber and polyisoprene rubber Can be mentioned. When blending rubber other than nitrile copolymer rubber (A) and nitrile copolymer rubber (B), the blending amount is 100 weights in total of nitrile copolymer rubber (A) and nitrile copolymer rubber (B). 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 nitrile copolymer rubber composition obtained by the above-described method is added with a crosslinking agent and other compounding agents, What is necessary is just to knead | mix with kneading machines, such as a Banbury mixer and a kneader.

In this case, the blending order is not particularly limited, but components (such as a crosslinking agent and a crosslinking accelerator) that are easily decomposed by heat after sufficiently mixing components that are not easily reacted or decomposed by heat do not decompose. What is necessary is just to mix for a short time below temperature.

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

<Rubber cross-linked product>
The rubber cross-linked product according to this embodiment is obtained by cross-linking the cross-linkable rubber composition of this embodiment described above.

When the crosslinkable rubber composition is crosslinked, it is molded by a molding machine corresponding to the shape of the molded article (rubber crosslinked product) to be produced, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and then crosslinked. By reacting, the shape of the crosslinked product is fixed. When performing the crosslinking, the crosslinking may be performed after molding in advance, or the crosslinking may be performed simultaneously with the molding. The molding temperature is usually 10 ° C. or higher, preferably 25 ° C. or higher, and is 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 is usually 200 ° C. or lower, preferably 190 ° C. or lower. The crosslinking time is usually 1 minute or longer, preferably 2 minutes or longer, and usually 24 hours or shorter, preferably 1 hour or shorter.

Depending on the shape, size, etc. of the rubber cross-linked product, even if the surface is cross-linked, it may not be sufficiently cross-linked to the inside. Therefore, secondary cross-linking may be performed by heating.

The rubber cross-linked product of the present embodiment thus obtained is excellent in molding processability as a rubber non-cross-linked product, and is obtained using the nitrile rubber composition and cross-linkable rubber composition of the present embodiment described above. Therefore, it has excellent strength characteristics, oil resistance, and ozone resistance.

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

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Unless otherwise specified, “parts” are based on weight. The test or evaluation method of physical properties and characteristics is as follows.

[Methyl ethyl ketone insoluble content (MEK insoluble content)]
0.2 g of nitrile copolymer rubber (nitrile group-containing polymer) is placed in an 80 mesh wire mesh, immersed in 50 ml of methyl ethyl ketone (hereinafter referred to as MEK) for 24 hours at room temperature, then the wire mesh is taken out, and 10 minutes at room temperature. Dried. Thereafter, the MEK insoluble matter was measured from the weight of the polymer remaining on the 80-mesh wire mesh. The MEK insoluble content (%) was calculated by the following formula.
MEK insoluble content (%) = (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)

[Mooney 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 minimum Mooney viscosity (125 ° C.) was used as an index of the deformability of the crosslinkable rubber composition. In addition, when the minimum Mooney viscosity (125 degreeC) was 33 or more, the shape maintenance property at the time of a shaping | molding process was favorable, and when less than 33, the shape maintenance property at the time of a shaping | molding process was inferior.

[Strength characteristics (100% tensile stress of uncrosslinked and crosslinked products)]
The crosslinkable rubber composition is placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, press-molded at 100 ° C. for 2 minutes while being pressurized, and then 30 minutes while circulating cooling water at room temperature. An uncrosslinked rubber 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 crosslinked rubber product. Using the obtained sheet-shaped rubber uncrosslinked product and rubber crosslinked product in accordance with JIS K6251 and using a test piece punched out in the shape of dumbbell No. 3, 100% tensile strength of the rubber uncrosslinked product and rubber crosslinked product as normal properties Stress (MPa) was measured. The 100% tensile stress of the rubber uncrosslinked product was evaluated as excellent in strength characteristics at 2.0 MPa or more, and evaluated as inferior in strength characteristics at less than 2.0 MPa. Further, the 100% tensile stress of the rubber cross-linked product was evaluated as excellent in strength characteristics at 4.6 MPa or more, and evaluated as inferior in strength characteristics at less than 4.6 MPa.

[Fuel resistant oil immersion test (toluene / isooctane = 50/50)]
A test piece obtained by punching a rubber cross-linked product obtained by cross-linking the same cross-linkable rubber composition used for evaluation of the above-described normal physical properties into a size of 30 mm × 20 mm × 2 mm was used as toluene / isooctane = 50/50. The fuel oil immersion test was conducted by immersing in (volume ratio) fuel oil (Fuel-C) 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 swelling degree ΔV after immersion (unit:%) = ([volume after oil immersion−volume before oil immersion] / volume before oil immersion) × 100
As the volume swelling degree ΔV after immersion was closer to 0%, it was evaluated that the oil resistance was excellent, and when ΔV was 25% or more, the oil resistance was evaluated as inferior.

[Static ozone degradation test (ozone resistance)]
Using the same sheet-like rubber cross-linked product used in the evaluation of the fuel oil immersion test, the state after 120 hours was evaluated according to JIS K6259 under the conditions of 40 ° C., ozone concentration of 50 pphm, and 30% elongation. . The crack evaluation method was in accordance with the crack state evaluation method described in JIS K6259-1. When the crack could not be observed with a 10 × magnifier, it was expressed as NC. In addition, when the result of the static ozone deterioration test was NC, it was evaluated as being excellent in 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))
A 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. Next, after the gas phase is depressurized and sufficiently degassed, 66 parts of 1,3-butadiene, 0.04 part of p-menthane hydroperoxide as a polymerization initiator, 0.02 part of sodium ethylenediaminetetraacetate, sulfuric acid The first stage reaction of the emulsion polymerization was started by adding 0.006 part of ferrous iron (7 water salt), 0.06 part of sodium formaldehyde sulfoxylate and 1 part of t-dodecyl mercaptan as a chain transfer agent. Thereafter, when the polymerization conversion rate with respect to all 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 unreacted monomers were recovered by steam distillation under reduced pressure to obtain latex of nitrile copolymer rubber (A-1) (solid content 26 wt. %). Next, after adding 2 volumes of methanol to the obtained latex and coagulating, it was vacuum-dried at 60 ° C. for 12 hours to obtain a nitrile copolymer rubber (A-1). As a result of measuring the composition of each monomer unit of the obtained nitrile copolymer rubber (A-1) by ¹ H-NMR, 33.5% by weight of acrylonitrile unit (AN amount), 1,3-butadiene unit 65.5% by weight and 1% by weight of trimethylolpropane trimethacrylate. The methyl ethyl ketone insoluble content (MEK insoluble content) was 81%, and the polymer Mooney viscosity [ML1 + 4, 100 ° C.] was 78.

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

[Production Example 3] (Production of nitrile copolymer rubber (B-1))
A reaction vessel was charged with 240 parts of water, 75.7 parts of acrylonitrile and 2.5 parts of sodium dodecylbenzenesulfonate (emulsifier), and the temperature was adjusted to 5 ° C. Next, after the gas phase is depressurized and sufficiently deaerated, 22 parts of 1,3-butadiene, 0.06 part of p-menthane hydroperoxide as a polymerization initiator, 0.02 part of sodium ethylenediaminetetraacetate, sulfuric acid The first stage reaction of the emulsion polymerization was started by adding 0.006 part of ferrous iron (7 water salt), 0.06 part of sodium formaldehyde sulfoxylate and 1 part of t-dodecyl mercaptan as a chain transfer agent. After the start of the reaction, when the polymerization conversion ratio 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. The polymerization reaction of the second and third stages was performed. Thereafter, when the polymerization conversion ratio with respect to all 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 unreacted monomers were recovered by steam distillation under reduced pressure to obtain a latex of nitrile copolymer rubber (B-1) (solid content: 24 wt. %). 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). For the obtained nitrile copolymer rubber (B-1), the composition of each monomer unit was measured in the same manner as in Production Example 1. As a result, 50% by weight of acrylonitrile unit (AN amount), 1,3-butadiene unit 50% by weight, the methyl ethyl ketone insoluble content (MEK insoluble content) 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 the emulsion polymerization, the charged amount of acrylonitrile is 44 parts, trimethylolpropane trimethacrylate is not used, and the added amount of 1,3-butadiene is 56 parts. 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. Subsequently, as in Production Example 1, the composition of each monomer unit of the obtained nitrile copolymer rubber (B-2) was measured. As a result, the acrylonitrile unit (AN amount) was 40.5% by weight, 1, 3 -The butadiene unit was 59.5% by weight. The methyl ethyl ketone insoluble content (MEK insoluble content) 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 nitrile copolymer rubber 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 Co., Ltd.), di (butoxyethoxyethyl) adipate (trade name) Add ADEKA SIZER RS-107, manufactured by ADEKA, plasticizer, “ADEKA SIZER” is a registered trademark, the same shall apply hereinafter) 5 parts, and knead at 175 ° C. with a Banbury mixer. A combined rubber composition was obtained. Next, to the nitrile copolymer rubber composition obtained above, FEF carbon (trade name “SEAST SO”, manufactured by Tokai Carbon Co., Ltd., filler, “SEAST” is a registered trademark) 45 parts, zinc oxide 5 parts, 25 parts of di (butoxyethoxyethyl) adipate (plasticizer) was added and kneaded at 140 ° C. with a Banbury mixer to obtain a rubber composition. Next, the obtained rubber composition was wound around a roll heated to 50 ° C., 325 mesh sulfur (crosslinking agent) 0.3 part, di-2-benzothiazolyl disulfide (crosslinking accelerator) 1.5 part, Further, 1.5 parts of tetramethylthiuram disulfide (crosslinking accelerator) was 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 properties (100% tensile stress), and normal rubber properties (100% tensile stress) (100% tensile stress), fuel oil immersion test, and static ozone deterioration test. The results are shown in Table 1. In Example 1, the nitrile copolymer rubber (A-1) is the nitrile copolymer rubber A, and the combination of the nitrile copolymer rubber (B-1) and the nitrile copolymer rubber (B-2) is used. When the nitrile copolymer rubber B was used, the acrylonitrile content (AN amount) was 45.2% by weight with respect to the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 2]
The amount of nitrile copolymer rubber (A-1) obtained in Production Example 1 is 20 parts, the amount of nitrile copolymer rubber (B-1) obtained in Production Example 3 is 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 content (AN amount) of acrylonitrile with respect to the total of the combined rubber A and the nitrile copolymer rubber B was 45.3% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

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

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

[Example 5]
The amount of nitrile copolymer rubber (A-1) obtained in Production Example 1 was 8.6 parts, and the amount of 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 performed in the same manner. The results are shown in Table 1. In Example 5, as in Example 1, when nitrile copolymer rubber A and nitrile copolymer rubber B were used, acrylonitrile was used with respect to the total of nitrile copolymer rubber A and nitrile copolymer rubber B. The content (AN amount) of was 45.2% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total 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 performed 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 rubber A The content (AN amount) of acrylonitrile with respect to the total of the combined rubber A and the nitrile copolymer rubber B was 39.5% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Example 7]
Similar to 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 united rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was performed in the same manner. The results are shown in Table 1. In Example 7, when the nitrile copolymer rubber (A-2) is a nitrile copolymer rubber A and the nitrile copolymer rubber (B-1) is a nitrile copolymer rubber B, The content (AN amount) of acrylonitrile with respect to the total of the combined rubber A and the nitrile copolymer rubber B was 45.3% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 1]
The amount of nitrile copolymer rubber (A-1) obtained in Production Example 1 was 11.4 parts, and the amount of 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 performed in the same manner. The results are shown in Table 1. In Comparative Example 1, as in Example 1, when nitrile copolymer rubber A and nitrile copolymer rubber B were used, acrylonitrile was used with respect to the total of nitrile copolymer rubber A and nitrile copolymer rubber B. The content (AN amount) of was 45.2% by weight. The blending ratio of the vinyl chloride resin to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 25 parts.

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

[Comparative Example 3]
Implementation was performed except that the amount of the nitrile copolymer rubber (A-2) obtained in Production Example 2 was changed to 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 performed 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 (AN amount) of acrylonitrile with respect to the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 33.5% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

[Comparative Example 4]
Except not using the nitrile copolymer rubber (A-1) obtained in Production Example 1 and using 70 parts of the nitrile copolymer rubber (A-2) obtained in Production Example 2, Similarly to Comparative Example 3, a nitrile copolymer rubber composition and a crosslinkable rubber composition were obtained, and each test and evaluation was performed in the same manner. The results are shown in Table 1. In Comparative Example 4, when the nitrile copolymer rubber (A-2) is the nitrile copolymer rubber A and the nitrile copolymer rubber B is not used, the nitrile copolymer rubber A and the nitrile copolymer are used. The content (AN amount) of acrylonitrile with respect to the total amount of rubber B was 33.5% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total 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. Production Example 4 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 the above was changed to 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 (AN amount) of acrylonitrile with respect to the total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 45.9% by weight. Moreover, the compounding ratio of the vinyl chloride resin with respect to 100 parts in total of the nitrile copolymer rubber A and the nitrile copolymer rubber B was 43 parts.

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

On the other hand, a nitrile copolymer rubber (A) containing less than 40% by weight of an α, β-ethylenically unsaturated nitrile monomer unit and 40% by weight or more of an α, β-ethylenically unsaturated nitrile monomer unit Containing nitrile copolymer rubber (B) and vinyl chloride resin (C) having an average degree of polymerization of 800 or more, a total of 100 nitrile copolymer rubber (A) and nitrile copolymer rubber (B) The 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 is the molding processability of the resulting rubber uncrosslinked product, the strength properties of the rubber crosslinked product, It was inferior in at least one of oil resistance and ozone resistance (Comparative Examples 1 to 5).

The embodiments of the present invention have been described with reference to the examples. However, the present invention is not limited to the specific embodiments and examples, and various modifications can be made within the scope of the invention described in the claims. Can be modified and changed.

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

Claims

a nitrile copolymer rubber (A) containing less than 40% by weight of an α, β-ethylenically unsaturated nitrile monomer unit;
a nitrile copolymer rubber (B) containing 40% by weight or more of an α, β-ethylenically unsaturated nitrile monomer unit;
A vinyl chloride resin (C) having an average degree of polymerization of 800 or more,
Nitrile copolymer rubber composition in which the content of the vinyl chloride resin (C) is 35 parts by weight or more with respect to 100 parts by weight of the total of the nitrile copolymer rubber (A) and the nitrile copolymer rubber (B) .
The nitrile copolymer rubber composition according to claim 1, wherein the nitrile copolymer rubber (A) has a methylethylketone (MEK) insoluble content of 60% or more.
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. 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 nitrile copolymer rubber composition according to any one of claims 1 to 4 with a crosslinking agent.
A rubber cross-linked product obtained by cross-linking the cross-linkable rubber composition according to claim 5.
A hose comprising the nitrile copolymer rubber composition according to any one of claims 1 to 4.