WO2018117037A1

WO2018117037A1 - Acrylic rubber, acrylic rubber composition, crosslinked acrylic rubber, and production method for acrylic rubber

Info

Publication number: WO2018117037A1
Application number: PCT/JP2017/045358
Authority: WO
Inventors: 文明坂東
Original assignee: 日本ゼオン株式会社
Priority date: 2016-12-22
Filing date: 2017-12-18
Publication date: 2018-06-28
Also published as: JP6813031B2; JPWO2018117037A1

Abstract

An acrylic rubber having an acrylate ester monomer unit and a constituent unit that is derived from a cross-linkable monomer. The acrylic rubber has a weight-average molecular weight of 1,000,000–4,000,000 and an oligomer amount of no more than 5%.

Description

Acrylic rubber, acrylic rubber composition, cross-linked acrylic rubber, and method for producing acrylic rubber

The present invention relates to an acrylic rubber, an acrylic rubber composition, a crosslinked acrylic rubber, and a method for producing the acrylic rubber.

Acrylic rubber is widely used as a rubber material from which a rubber cross-linked product excellent in heat resistance, oil resistance and aging resistance can be obtained, for various sealing materials mainly for automobile use, and functional parts such as hoses. On the other hand, acrylic rubber rubber cross-linked products tend to be inferior in tensile strength, cold resistance, and processability. Therefore, acrylic rubber that has improved mechanical properties such as tensile strength, elongation, compression set resistance of rubber cross-linked products has been conventionally used. Rubber has been studied.

Generally, an attempt to improve the mechanical properties of a rubber cross-linked product is accompanied by a decrease in the elongation of the rubber cross-linked product. The weight average molecular weight of acrylic rubber is usually in the range of 50,000 to 1,000,000, and as the molecular weight of acrylic rubber is increased, the mechanical properties of the rubber cross-linked product are improved. It is known to saturate at. On the other hand, Japanese Patent No. 3618347 (Patent Document 1) discloses a technique for increasing the molecular weight of acrylic rubber using a highly deoxygenated polymerization reaction system.

Japanese Patent No. 3618347

However, in Patent Document 1, if the molecular weight of the acrylic rubber is increased by using the method disclosed in Patent Document 1, the tensile strength and elongation of the rubber cross-linked product can both be achieved. It is stated that the effect cannot be obtained unless the value is raised to an extremely high value of 8,000,000. Moreover, in the technique disclosed in Patent Document 1, acrylic rubber must be manufactured using a special reaction system that is highly deoxygenated, which increases the manufacturing cost or makes it difficult to substantially manufacture the rubber. There is a problem that there is. Furthermore, when the technique disclosed in Patent Document 1 is used, it is easily imagined that the processability of the acrylic rubber or the acrylic rubber composition is lowered.

An object of the present invention is to provide an acrylic rubber that improves the tensile strength while maintaining the elongation of the rubber cross-linked product.

In order to solve the above problems, an acrylic rubber according to an embodiment of the present invention has an acrylate monomer and a structural unit derived from a crosslinkable monomer, and has a weight average molecular weight of 1,000,000 to 4,000,000 and the amount of oligomer is 5% or less.

According to one embodiment of the present invention, it is possible to provide an acrylic rubber that improves the tensile strength while maintaining the elongation of the crosslinked rubber.

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

<Acrylic rubber>
The acrylic rubber according to the embodiment of the present invention has an acrylate monomer unit and a structural unit derived from a crosslinkable monomer, and has a weight average molecular weight of 1,000,000 to 4,000,000. Yes, an acrylic rubber having an oligomer amount of 5% or less.

The acrylate monomer unit contained in the acrylic rubber of this embodiment constitutes the main component of the acrylic rubber according to this embodiment.

The acrylate monomer constituting the acrylate monomer unit is not particularly limited. As the acrylic acid ester monomer, for example, a (meth) acrylic acid alkyl ester monomer or a (meth) acrylic acid alkoxyalkyl ester monomer is preferable. In the present specification, “(meth) acrylic acid” means both “acrylic acid” and “methacrylic acid”.

The (meth) acrylic acid alkyl ester monomer is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, Linear or branched alkyl groups having 1 to 8 carbon atoms such as n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Alkyl ester monomers; cycloalkyl ester monomers having 4 to 8 carbon atoms in the cycloalkyl group such as cyclohexyl (meth) acrylate; and the like. Among these, linear or branched (meth) acrylic acid alkyl ester monomers having 1 to 8 carbon atoms in the alkyl group are preferable, ethyl (meth) acrylate and n-butyl (meth) acrylate are more preferable. Particularly preferred are ethyl acrylate and n-butyl acrylate. These may be used alone or in combination of two or more.

The (meth) acrylic acid alkoxyalkyl ester monomer is not particularly limited. However, methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, and (meth) acrylic acid. Alkoxyalkyl groups such as 2-ethoxyethyl, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, and 4-methoxybutyl (meth) acrylate And alkoxyalkyl ester monomers having 2 to 8 carbon atoms. Among these, (meth) acrylic acid alkoxyalkyl ester monomers having 3 to 5 carbon atoms in the alkoxyalkyl group are preferable, and 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate are more preferable. Preferably 2-methoxyethyl acrylate is particularly preferred. These may be used alone or in combination of two or more. Furthermore, these (meth) acrylic acid alkoxyalkyl ester monomers may be used in combination with the aforementioned (meth) acrylic acid alkyl ester monomers.

The content of the acrylate monomer unit is preferably 50 to 99.9% by weight, more preferably 60 to 99.7% by weight based on 100% by weight of the total monomer units constituting the acrylic rubber. %, More preferably 70 to 99.5% by weight. If the content of the (meth) acrylic acid ester monomer unit is too small, the weather resistance, heat resistance, and oil resistance of the resulting rubber cross-linked product may be deteriorated. When there is too much content of a body unit, there exists a possibility that the heat resistance of the rubber crosslinked material obtained may fall.

In the present embodiment, the content of the acrylic acid ester monomer unit is 30 to 100% by weight of the (meth) acrylic acid alkyl ester monomer unit, and the (meth) acrylic acid alkoxyalkyl ester monomer unit is 0%. It is preferably composed of 70 to 70% by weight, and consists of 50 to 100% by weight of (meth) acrylic acid alkyl ester monomer units and 0 to 50% by weight of (meth) acrylic acid alkoxyalkyl ester monomer units. More preferably.

The structural unit derived from the crosslinkable monomer contained in the acrylic rubber according to the present embodiment is a structural unit derived from the crosslinkable monomer having a crosslinkable group in the side chain. Although it does not specifically limit as a crosslinkable group which comprises the side chain of this crosslinkable monomer, It may be a crosslinkable group which has any 1 type, or 2 or more types of an epoxy group, a halogen group, and a carboxyl group. preferable.

Examples of the crosslinkable monomer having an epoxy group include epoxy group-containing ethers such as epoxy group-containing (meth) acrylate esters such as glycidyl (meth) acrylate, vinyl glycidyl ether, and allyl glycidyl ether. Of these, glycidyl (meth) acrylate and allyl glycidyl ether are preferable.

The crosslinkable monomer having a carboxyl group is not particularly limited, and examples thereof include α, β-ethylenically unsaturated carboxylic acid monomers. Examples of the α, β-ethylenically unsaturated carboxylic acid monomer include α, β-ethylenically unsaturated monocarboxylic acids having 3 to 12 carbon atoms and α, β-ethylenically unsaturated atoms having 4 to 12 carbon atoms. And dicarboxylic acids and monoesters of α, β-ethylenically unsaturated dicarboxylic acids having 4 to 12 carbon atoms and alkanols having 1 to 8 carbon atoms.

Specific examples of the α, β-ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms include acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, and cinnamic acid.

Specific examples of the α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms include butenedionic acid such as fumaric acid and maleic acid; itaconic acid; citraconic acid; chloromaleic acid;

Specific examples of monoesters of α, β-ethylenically unsaturated dicarboxylic acids having 4 to 12 carbon atoms and alkanols having 1 to 8 carbon atoms include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, malein Butenedionic acid mono-chain alkyl esters such as monomethyl acid, monoethyl maleate, mono-n-butyl maleate; monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, maleate Butenedionic acid monoesters having an alicyclic structure such as acid monocyclohexenyl; itaconic acid monoesters such as monomethyl itaconate, monoethyl itaconate, mono n-butyl itaconate, monocyclohexyl itaconate; and the like.

Among these, butenedionic acid mono-chain alkyl ester or butenedionic acid monoester having an alicyclic structure is preferable, and mono n-butyl fumarate, mono n-butyl maleate, monocyclohexyl fumarate, and monocyclohexyl maleate are preferable. More preferred is mono n-butyl fumarate. These α, β-ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. Among the above monomers, the α, β-ethylenically unsaturated dicarboxylic acid includes those existing as anhydrides.

Although it does not specifically limit as a crosslinkable monomer which has a halogen group, Unsaturated alcohol ester of halogen-containing saturated carboxylic acid, (meth) acrylic acid haloalkyl ester, (meth) acrylic acid haloacyloxyalkyl ester, (meth) acrylic Examples include acid (haloacetylcarbamoyloxy) alkyl esters, halogen-containing unsaturated ethers, halogen-containing unsaturated ketones, halomethyl group-containing aromatic vinyl compounds, halogen-containing unsaturated amides, and haloacetyl group-containing unsaturated monomers.

Specific examples of the unsaturated alcohol ester of a halogen-containing saturated carboxylic acid include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate.

Specific examples of (meth) acrylic acid haloalkyl esters include chloromethyl (meth) acrylate, 1-chloroethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 1,2-dichloroethyl (meth) acrylate. , 2-chloropropyl (meth) acrylate, 3-chloropropyl (meth) acrylate, 2,3-dichloropropyl (meth) acrylate, and the like.

Specific examples of (meth) acrylic acid haloacyloxyalkyl esters include 2- (chloroacetoxy) ethyl (meth) acrylate, 2- (chloroacetoxy) propyl (meth) acrylate, and 3- (chloro) (meth) acrylic acid. Acetoxy) propyl, 3- (hydroxychloroacetoxy) propyl (meth) acrylate, and the like.

Specific examples of (meth) acrylic acid (haloacetylcarbamoyloxy) alkyl esters include 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate and 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate Is mentioned.

Specific examples of the halogen-containing unsaturated ether include chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, and 3-chloropropyl allyl ether.

Specific examples of the halogen-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone.

Specific examples of the halomethyl group-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, and p-chloromethyl-α-methylstyrene.

Specific examples of halogen-containing unsaturated amides include N-chloromethyl (meth) acrylamide.

Specific examples of the haloacetyl group-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether, p-vinylbenzyl chloroacetate and the like. These crosslinkable monomers may be used alone or in combination of two or more.

The content of the structural unit derived from the crosslinkable monomer can be 0.1 to 10% by weight with respect to a total of 100% by weight of all the monomer units constituting the acrylic rubber according to this embodiment. Preferably, the content is 0.3 to 8% by weight, and more preferably 0.5 to 5% by weight. If the structural unit derived from the crosslinkable monomer is less than 0.1% by weight, the acrylic rubber is not sufficiently crosslinked, and sufficient mechanical properties (for example, tensile strength, elongation, compression resistance of the crosslinked rubber) Permanent set, etc.) cannot be obtained. Moreover, when it exceeds 10 weight%, an acrylic rubber will be bridge | crosslinked excessively and elongation will fall.

As long as the acrylic rubber according to the present embodiment maintains the characteristics of the acrylic rubber, in addition to the above-mentioned acrylic ester monomer unit and the structural unit derived from the crosslinkable monomer, other monomers that can be copolymerized are used. You may have the unit of.

Other monomers that can be copolymerized are not particularly limited. For example, aromatic vinyl monomers (except those corresponding to the above-mentioned polyfunctional monomers), α, β-ethylenic monomers, etc. Examples include unsaturated nitrile monomers, olefinic monomers, and vinyl ether compounds.

Specific examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-dimethylaminostyrene, divinylbenzene, 2-vinylpyridine, 4-vinylpyridine and the like.

Specific examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.

Specific examples of the olefin monomer include ethylene, propylene, 1-butene, 1-octene, vinyl chloride, vinylidene chloride and the like.

Specific examples of the vinyl ether compound include vinyl acetate, ethyl vinyl ether, dimethylaminoethyl vinyl ether, and n-butyl vinyl ether.

In addition to these, monomers having two or more (meth) acryloyloxy groups such as (meth) acrylic acid diester of ethylene glycol and (meth) acrylic acid diester of propylene glycol (polyfunctional acrylic monomer) , Acrylamide, N-hydroxy (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, and the like. .

Among these, styrene, acrylonitrile, methacrylonitrile, ethylene and vinyl acetate are preferable, and acrylonitrile, methacrylonitrile and ethylene are more preferable.

Other copolymerizable monomers may be used alone or in combination of two or more. In this embodiment, the content of other monomer units in the acrylic rubber is 40% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less.

The molecular weight of the acrylic rubber according to this embodiment is 1,000,000 to 4,000,000, preferably 1,500,000 to 4,000,000 in terms of weight average molecular weight (Mw). If the molecular weight of the acrylic rubber is less than 1,000,000, sufficient mechanical properties cannot be obtained as a cross-linked product of the acrylic rubber. There is a tendency for the processability to deteriorate. In addition, in this specification, a weight average molecular weight means the weight average molecular weight (Mw) of polystyrene conversion by gel permeation chromatography.

The acrylic rubber according to the present embodiment has a content ratio of a composition having a weight average molecular weight of 100,000 or less (hereinafter referred to as oligomer amount) of 5% or less, preferably 0.1 to 4.5%. Or less, and more preferably 0.5 to 4.0%. When the amount of the oligomer is 5% or less, a crosslinked rubber having excellent mechanical properties can be obtained without reducing elongation. If the amount of oligomer exceeds 5%, sufficient tensile strength cannot be obtained.

In addition, since the component whose weight average molecular weight containing the oligomer in acrylic rubber is 100,000 or less is comparatively easy to quantify, the component of the weight average molecular weight containing the oligomer in acrylic rubber composition is 100,000 or less. The content (%) was defined as the amount of oligomer.

As described above, the acrylic rubber according to this embodiment contains an acrylate monomer and a structural unit derived from a crosslinkable monomer having a crosslinkable group in the side chain, and has a weight average molecular weight of 1,000. The amount of oligomer having a weight average molecular weight of 100,000 or less is adjusted to 5% or less. By using such an acrylic rubber, a rubber cross-linked product having excellent tensile strength can be obtained while maintaining elongation and compression set resistance.

The molecular weight distribution of the acrylic rubber according to this embodiment is not particularly limited, but is preferably 1.3 to 3.0, and more preferably 1.4 to 2.9. In this specification, molecular weight distribution means the ratio (Mw / Mn) of polystyrene-equivalent number average molecular weight (Mn) and weight average molecular weight (Mw) by gel permeation chromatography.

In the acrylic rubber according to the present embodiment, the molecular weight distribution can be adjusted in such a range as a result of increasing the molecular weight while maintaining a small oligomer component. That is, by adjusting the molecular weight distribution of the acrylic rubber to 1.3 to 3.0, a rubber cross-linked product having excellent tensile strength can be reliably obtained while maintaining elongation and compression set resistance.

<Method for producing acrylic rubber>
The method for producing an acrylic rubber according to this embodiment comprises an emulsion polymerization or suspension of an acrylate monomer and a crosslinkable monomer having a crosslinkable group in a side chain in the presence of a living radical polymerization initiator. Copolymerization (living radical polymerization) is performed by polymerization.

The acrylic ester monomer used in the production method of the present embodiment is not particularly limited as long as it is capable of living radical polymerization, and the above acrylic ester monomer can be used.

The crosslinkable monomer having a crosslinkable group in the side chain used in the production method of the present embodiment is not particularly limited as long as it is capable of living radical polymerization with the above acrylate ester, and the above crosslinkable single monomer. A mer can be used.

The polymerization initiator used in the method for producing acrylic rubber according to this embodiment is a living radical polymerization initiator. By carrying out emulsion polymerization or suspension polymerization in the presence of this living radical polymerization initiator, the acrylic acid ester monomer and the crosslinkable monomer are copolymerized by living radical polymerization, and the acrylic rubber copolymer is copolymerized. A polymer is obtained. When the acrylic rubber copolymer thus obtained is cross-linked, a rubber cross-linked product having excellent tensile strength can be obtained while maintaining elongation and compression set resistance.

Although it does not specifically limit as a living radical polymerization initiator used with the manufacturing method of the acrylic rubber which concerns on this embodiment, For example, an organic tellurium compound can be used. As such an organic tellurium compound, an organic tellurium compound represented by the following general formula (1) is preferably used.

In the general formula (1), R ¹ represents an alkyl group, an unsubstituted or substituted cycloalkyl group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted aromatic heterocyclic group, and R ² and R ³ each represents Independently, it represents a hydrogen atom or an alkyl group, and R ⁴ represents an unsubstituted or substituted vinyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted aromatic heterocyclic group, an acyl group, a hydrocarbyloxycarbonyl group or a cyano group. Show.

In the present specification, “unsubstituted or substituted” means that a substituent such as a cycloalkyl group may have another substituent except for a hydrogen atom and a deuterium atom. These other substituents may be bonded to each other to form a ring.

The number of carbon atoms of the alkyl group of R ¹ is not particularly limited, but is preferably 1 to 10, more preferably 1 to 8, and further preferably 1 to 5 from the viewpoint of availability. Examples of the alkyl group for R ¹ include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n -Straight chain alkyl groups such as decyl group; branched alkyl groups such as isopropyl group, sec-butyl group and tert-butyl group.

The carbon number of the unsubstituted or substituted cycloalkyl group of R ¹ is 3 to 10, preferably 3 to 8, and more preferably 5 or 6, from the viewpoint of availability. Examples of the unsubstituted or substituted cycloalkyl group of R ¹ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and the like.

The substituent of the unsubstituted or substituted cycloalkyl group of R ¹ is not particularly limited as long as it does not interfere with the polymerization reaction. For example, halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; hydroxyl group; alkyl group having 1 to 8 carbon atoms such as methyl group, ethyl group, n-propyl group and isopropyl group; methoxy group, ethoxy group and the like An alkoxy group having 1 to 8 carbon atoms; an amino group; a nitro group; a cyano group; a group represented by —CORa (where Ra is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. An alkyl group; a cycloalkyl group having 3 to 8 carbon atoms such as a cyclopropyl group, a cyclobutyl group and a cyclopentyl group; an aryl group having 6 to 10 carbon atoms such as a phenyl group, a 1-naphthyl group and a 2-naphthyl group; a methoxy group; An alkoxy group having 1 to 8 carbon atoms such as an ethoxy group; an unsubstituted or substituted aryloxy having 6 to 10 carbon atoms such as a phenoxy group and a 2,4,6-trimethylphenyloxy group; Group; a haloalkyl group having 1 to 8 carbon atoms such as a trifluoromethyl group); and the like.

The unsubstituted or substituted aryl group of R ¹ has 6 to 20 carbon atoms, preferably 6 to 15 and more preferably 6 to 10 from the viewpoint of availability. Examples of the aryl group of the unsubstituted or substituted aryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, and an anthranyl group. The substituent of the unsubstituted or substituted aryl group is not particularly limited as long as it does not interfere with the polymerization reaction. For example, the thing similar to what was shown as a substituent of an unsubstituted or substituted cycloalkyl group is mentioned.

The unsubstituted or substituted aromatic heterocyclic group for R ¹ has 1 to 15 carbon atoms, preferably 3 to 15 and more preferably 4 to 10 from the viewpoint of availability. As an aromatic heterocyclic group of an unsubstituted or substituted aromatic heterocyclic group, a 5-membered aromatic heterocyclic group such as a pyrrolyl group, an imidazolyl group, a furyl group, a thienyl group, an oxazolyl group, a thiazolyl group; a pyridyl group, 6-membered aromatic heterocyclic groups such as pyrimidyl group, pyridazyl group and pyrazinyl group; condensed aromatic heterocyclic groups such as benzimidazolyl group, quinolyl group and benzofuranyl group;

The substituent of the unsubstituted or substituted aromatic heterocyclic group for R ¹ is not particularly limited as long as it does not interfere with the polymerization reaction. For example, the thing similar to what was shown as a substituent of an unsubstituted or substituted cycloalkyl group is mentioned.

The number of carbon atoms in the alkyl group of R ² and R ³ is preferably 1 to 10, more preferably 1 to 8, and further preferably 1 to 5.

Examples of the alkyl group for R ² and R ³ include alkyl groups having 1 to 10 carbon atoms such as a methyl group and an ethyl group; alkenyl groups having 2 to 10 carbon atoms such as a 1-propenyl group and a 2-propenyl group; 1-propynyl Groups, alkynyl groups having 2 to 10 carbon atoms such as 2-propynyl group: cycloalkyl groups having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; carbon numbers such as methoxycarbonyl and phenoxycarbonyl 2-20 hydrocarbyloxycarbonyl groups; and the like.

In general formula (1), R ⁴ represents an unsubstituted or substituted vinyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted aromatic heterocyclic group, an acyl group, a hydrocarbyloxycarbonyl group, or a cyano group.

Specific examples of the unsubstituted or substituted vinyl group for R ⁴ include an allyl group, an isopropenyl group, an acrylic group, a methacryl group, an olefin group, and a diene group.

Specific examples of the unsubstituted or substituted aryl group for R ⁴ include a phenyl group, a naphthyl group, a halogen atom-substituted phenyl group, a trifluoromethyl-substituted phenyl group, and the like.

Specific examples of the unsubstituted or substituted aromatic heterocyclic group for R ⁴ include a pyridyl group, a pyrrole group, a furyl group, and a thienyl group.

Specific examples of the acyl group for R ⁴ include formyl group, acetyl group, benzoyl group and the like.

Specific examples of the hydrocarbyloxycarbonyl group for R ⁴ include the same as those shown as the hydrocarbyloxycarbonyl group for R ² and R ³ .

In R ² to R ⁴ , two groups selected from these may be bonded to form a ring other than an aromatic ring. As the ring other than the aromatic ring, a hydrocarbon ring is preferable. The ring is preferably a 5- to 7-membered ring, more preferably a 6-membered ring. Examples of the substituent bonded to the ring are the same as those shown as the substituents for R ² to R ⁴ .

The organic tellurium compound represented by the general formula (1) is not limited. Specific examples of the organic tellurium compound include, for example, (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl-propyl) benzene, 1-chloro-4- (methylterranyl-methyl) benzene, 1 -Hydroxy-4- (methylterranyl-methyl) benzene, 1-methoxy-4- (methylterranyl-methyl) benzene, 1-amino-4- (methylterranyl-methyl) benzene, 1-nitro-4- (methylterranyl-methyl) benzene 1-cyano-4- (methylterranyl-methyl) benzene, 1-methylcarbonyl-4- (methylterranyl-methyl) benzene, 1-phenylcarbonyl-4- (methylterranyl-methyl) benzene, 1-methoxycarbonyl-4- ( Methylteranyl-methyl) benzene, -Phenoxycarbonyl-4- (methylterranyl-methyl) benzene, 1-sulfonyl-4- (methylterranyl-methyl) benzene, 1-trifluoromethyl-4- (methylterranyl-methyl) benzene, 1-chloro-4- (1- Methylterranyl-ethyl) benzene, 1-hydroxy-4- (1-methylterranyl-ethyl) benzene, 1-methoxy-4- (1-methylterranyl-ethyl) benzene, 1-amino-4- (1-methylterranyl-ethyl) benzene 1-nitro-4- (1-methylterranyl-ethyl) benzene, 1-cyano-4- (1-methylterranyl-ethyl) benzene, 1-methylcarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-phenyl Carbonyl-4- (1-methylterranyl-ethyl) benzene, 1-meth Sicarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-phenoxycarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-sulfonyl-4- (1-methylterranyl-ethyl) benzene, 1-trifluoromethyl -4- (1-methylterranyl-ethyl) benzene, 1-chloro-4- (2-methylterranyl-propyl) benzene, 1-hydroxy-4- (2-methylterranyl-propyl) benzene, 1-methoxy-4- (2 -Methylterranyl-propyl) benzene, 1-amino-4- (2-methylterranyl-propyl) benzene, 1-nitro-4- (2-methylterranyl-propyl) benzene, 1-cyano-4- (2-methylterranyl-propyl) Benzene, 1-methylcarbonyl-4- (2-methylterranyl-propyl) Benzene, 1-phenylcarbonyl-4- (2-methylterranyl-propyl) benzene, 1-methoxycarbonyl-4- (2-methylterranyl-propyl) benzene, 1-phenoxycarbonyl-4- (2-methylterranyl-propyl) benzene, 1-sulfonyl-4- (2-methylterranyl-propyl) benzene, 1-trifluoromethyl-4- (2-methylterranyl-propyl) benzene, 2- (methylterranyl-methyl) pyridine, 2- (1-methylterranyl-ethyl) Pyridine, 2- (2-methylterranyl-propyl) pyridine, methyl 2-methylterranyl ethanate, methyl 2-methylterranyl propionate, methyl 2-methyl-2-methylterranyl propionate, ethyl 2-methyl Terranyl ethanate, methyl 2-methylte Nylpropionate, ethyl 2-methyl-2-methyl terranyl propionate, 2-methyl terranyl acetonitrile, 2-methyl teranyl propionitrile, 2-methyl-2-methyl terranyl propionitrile, 3- Methyl terranyl-1-propene, 1-methyl terranyl-3-methyl-2-butene, 3-phenyl terranyl-1-propene, 3-butyl terranyl-1-propene, 3-cyclohexyl terranyl-1-propene, 3-methyl terranyl- 1-cyclohexene and the like can be mentioned. Among them, (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl-propyl) benzene, methyl 2-methyl-2-methylterranyl propionate, ethyl 2-methyl-2-methylterra Nylpropionate, ethyl 2-methyl-2-phenyl terranyl propionate, 2-methyl teranyl propionitrile, 2-methyl-2-methyl terranyl propionitrile, 3-methyl terranyl-1-propene, 3 -Phenylterranyl-1-propene and 3-butylterranyl-1-propene are preferred.

In the acrylic rubber production method of the present embodiment, controllability is achieved by living radical polymerization of an acrylate monomer and a crosslinkable monomer in the presence of the organic tellurium compound represented by the general formula (1). An excellent living radical polymerization reaction can be performed.

When the organic tellurium compound represented by the general formula (1), the acrylate monomer and the crosslinkable monomer (hereinafter, the acrylate monomer and the crosslinkable monomer are collectively referred to as a radical polymerizable monomer) May be adjusted as appropriate in consideration of the molecular weight and molecular weight distribution of the target polymer. Usually, the amount of the organic tellurium compound represented by the general formula (1) is 0.00001 to 0.001 mol, preferably 0.00002 to 0.0005 mol, relative to 1 mol of the radical polymerizable monomer.

Living radical polymerization is performed by, for example, an organic tellurium compound represented by the general formula (1), a radical polymerizable monomer, and, if necessary, in a container substituted with an inert gas such as nitrogen gas, helium gas, or argon gas. , By adding a solvent and stirring them at a predetermined temperature for a predetermined time, it can be carried out by emulsion polymerization or suspension polymerization.

As the solvent used for the polymerization reaction, water is usually used. The amount of the solvent to be used is not particularly limited, but is usually 50 to 2000 parts by weight, preferably 70 to 1500 parts by weight with respect to 100 parts by weight of the radical polymerizable monomer.

Examples of the emulsifier used in the polymerization reaction include an anionic surfactant, a cationic surfactant, and a nonionic surfactant.

Anionic surfactants include fatty acid salts such as sodium laurate, potassium myristate, sodium palmitate, potassium oleate, sodium linolenate, sodium rosinate, potassium rosinate; sodium dodecylbenzenesulfonate, dodecylbenzenesulfonate Alkylbenzene sulfonates such as potassium, sodium decylbenzenesulfonate, potassium decylbenzenesulfonate, sodium cetylbenzenesulfonate, potassium cetylbenzenesulfonate; sodium di (2-ethylhexyl) sulfosuccinate, di (2-ethylhexyl) sulfosuccinate Alkylsulfosuccinates such as potassium and sodium dioctylsulfosuccinate; alkylsulfates such as sodium dodecylsulfate and potassium dodecylsulfate Salts; polyoxyethylene alkyl ether sulfate salts such as sodium polyoxyethylene lauryl ether sulfate and potassium polyoxyethylene lauryl ether sulfate; phosphorus such as sodium lauryl phosphate, potassium lauryl phosphate and sodium polyoxyethylene nonylphenyl ether phosphate Acid ester salts; and the like. Of these anionic surfactants, alkyl sulfate salts and phosphate ester salts are preferred.

Examples of the cationic surfactant include alkyltrimethylammonium chloride, dialkylammonium chloride, and benzylammonium chloride.

Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol monostearate, sorbitan monostearate, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester, polyoxyethylene polyoxy Examples include propylene glycol and polyethylene glycol monostearate. Among these nonionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene glycol, and polyethylene glycol monostearate are preferable.

These emulsifiers can be used alone or in combination of two or more. The amount of the emulsifier used is not particularly limited, but is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the radical polymerizable monomer.

Examples of the dispersant used in the polymerization reaction include nonionic polymer compounds such as polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, and cellulose derivatives; polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, methacrylate esters and methacrylic acid and / or Or anionic polymer compounds such as copolymers with salts thereof; poorly water-soluble inorganic compounds such as calcium phosphate, calcium carbonate, aluminum hydroxide; and the like.

These dispersants can be used singly or in combination of two or more. The amount of the dispersant used is not particularly limited, but is usually 0.01 to 30 parts by weight, preferably 0.05 to 10 parts by weight with respect to 100 parts by weight of the radical polymerizable monomer.

In the presence of these emulsifiers, any method such as a batch system or a continuous or intermittent addition system is used at −10 to 100 ° C., preferably 0 to 80 ° C., for 1 minute to 100 hours, preferably 0. The polymerization reaction is carried out in 1 to 40 hours. The reaction is performed under normal pressure, but may be performed under pressure or under reduced pressure.

In the acrylic rubber production method of the present embodiment, a radical generator may be further present in the living radical polymerization reaction system. Such radical generators are not particularly limited as long as they generate radicals by heating or light irradiation, and azo compounds, peroxides, hydroperoxides, hydrogen peroxide, and persulfates are used. . Of these, azo compounds, peroxides, and persulfates are preferable. By conducting the polymerization reaction in the presence of such a radical generator in addition to the living radical polymerization initiator, the living radical polymerization reaction is further promoted, and an acrylic rubber polymer can be obtained efficiently.

The azo compound can be used without particular limitation as long as it is an azo compound used as a polymerization initiator or a polymerization accelerator in general radical polymerization. For example, 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2-methylbutyronitrile) (AMBN), 2,2′-azobis (2,4-dimethylvaleronitrile) ) (ADVN), 1,1′-azobis (cyclohexane-1-carbonitrile) (ACHN), dimethyl-2,2′-azobis (isobutyrate) (MAIB), 4,4′-azobis (4-cyanovaleric acid ) (ACVA), 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2′-azobis (2-methylbutyramide), 2,2′-azobis (4-methoxy-2,4) -Dimethylvaleronitrile), 2,2'-azobis (2-methylamidinopropane) dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propaline ], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (2,4,4-trimethylpentane), 2-cyano-2-propylazo Examples include formamide, 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2′-azobis (N-cyclohexyl-2-methylpropionamide), and the like. These azo compounds can be used alone or in combination of two or more.

These azo compounds are preferably selected as appropriate according to the reaction conditions. For example, when the polymerization reaction is performed at a low temperature (40 ° C. or lower), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile) is preferred. When the polymerization reaction is carried out at an intermediate temperature (40 to 80 ° C.), 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2-methylbutyro) Nitrile) (AMBN), dimethyl-2,2′-azobis (isobutyrate) (MAIB), 1,1′-azobis (1-acetoxy-1-phenylethane) are preferred, and the polymerization reaction is carried out at a high temperature (80 ° C. or higher). When performing, 1,1′-azobis (cyclohexane-1-carbonitrile) (ACHN), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl- - methylpropionamide), 2,2'-azobis (N- cyclohexyl-2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane) are preferred.

The peroxide can be used without particular limitation as long as it is a peroxide used as a polymerization initiator or polymerization accelerator in ordinary radical polymerization. Examples of such peroxides include diisobutyryl peroxide, diisopropyl peroxide, t-butyl peroxypivalate, dilauroyl peroxide, t-hexyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, t-butyl group. Organic peroxides such as mill peroxide, p-menthane hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide and the like can be mentioned.

The persulfate can be used without particular limitation as long as it is a persulfate used as a polymerization initiator or a polymerization accelerator in normal radical polymerization. Examples of such a persulfate include sodium peroxodisulfate, potassium peroxodisulfate, and ammonium peroxodisulfate.

When these radical generators are used, the amount used is, for example, 0.01 to 100 mol, preferably 0.05 to 10 mol, more preferably 0, relative to 1 mol of the organic tellurium compound represented by the general formula (1). .05 to 5 mol.

Further, in the method for producing a terminal-modified acrylic rubber of the present embodiment, the polymerization reaction may be performed while irradiating the polymerization reaction system with light. By conducting the polymerization reaction while irradiating the polymerization reaction system with light, the polymerization reaction is further promoted, and the polymer can be obtained efficiently.

The light to be irradiated is preferably ultraviolet light (light having a wavelength of 200 to 380 nm) or visible light (light having a wavelength of 380 to 830 nm). The light irradiation can be performed by a method generally used in the photopolymerization reaction, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp, a metal halide. Light may be irradiated using a light source such as a lamp, a xenon lamp, a krypton lamp, or an LED lamp.

It should be noted that both the radical generator and the light irradiation can be used in combination, but if either one is performed, the polymerization reaction is sufficiently accelerated.

Examples of the polymerization terminator include hydroxylamine, hydroxyamine sulfate, diethylhydroxyamine, hydroxyaminesulfonic acid and its alkali metal salt, sodium dimethyldithiocarbamate, hydroquinone and the like. The amount of the polymerization terminator used is not particularly limited, but is usually 0.1 to 2 parts by weight with respect to 100 parts by weight of the radical polymerizable monomer.

In the emulsion polymerization, polymerization auxiliary materials such as a molecular weight adjusting agent, a particle size adjusting agent, a chelating agent, and an oxygen scavenger can be used as necessary.

In addition to the radical generator described above, in the method for producing acrylic rubber according to the present embodiment, a ditelluride compound represented by the following formula (2) may further be present in the living radical polymerization reaction system.

By conducting the polymerization reaction in the presence of such a ditelluride compound in addition to the living radical polymerization initiator, the polymerization reaction is better controlled, and a polymer having a molecular weight closer to the theoretical value and a narrow molecular weight distribution is obtained. Obtainable.

In general formula (2), R ⁵ and R ⁶ each independently represent an alkyl group, an unsubstituted or substituted cycloalkyl group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted aromatic heterocyclic group.

Specific examples of the alkyl group, unsubstituted or substituted cycloalkyl group, unsubstituted or substituted aryl group, or unsubstituted or substituted aromatic heterocyclic group represented by R ⁵ and R ⁶ are R ¹ in the general formula (1), respectively. And the same as those shown as the alkyl group, unsubstituted or substituted cycloalkyl group, unsubstituted or substituted aryl group, or unsubstituted or substituted aromatic heterocyclic group.

Specific examples of the ditelluride compound represented by the general formula (2) include dimethylditelluride, diethylditelluride, di (n-propyl) ditelluride, diisopropylditelluride, dicyclopropylditelluride, di (n- Butyl) ditelluride, di (sec-butyl) ditelluride, di (tert-butyl) ditelluride, dicyclobutylditelluride, diphenylditelluride, bis (p-methoxyphenyl) ditelluride, bis (p-aminophenyl) ditelluride, Examples include bis (p-nitrophenyl) ditelluride, bis (p-cyanophenyl) ditelluride, bis (p-sulfonylphenyl) ditelluride, bis (2-naphthyl) ditelluride, 4,4′-dipyridylditelluride. These ditelluride compounds can be used individually by 1 type or in combination of 2 or more types.

When the ditelluride compound represented by the general formula (2) is used, the amount used is, for example, 0.01 to 1 mol with respect to 1 mol of the living radical polymerization initiator (the organic tellurium compound represented by the above general formula (1)). 100 mol, preferably 0.1 to 10 mol, more preferably 0.1 to 5 mol.

In addition, the use of the ditelluride compound represented by the general formula (2) can be used in combination with the use of the above-described radical generator and light irradiation.

After completion of the reaction, the polymer can be isolated and purified according to a conventional method. For example, after removing unreacted monomers from the obtained latex by steam distillation or the like, an anti-aging agent such as phenols or amines is added, and this system and a metal salt aqueous solution (for example, an aluminum sulfate aqueous solution, chloride) are added. A copolymer (acrylic rubber of this embodiment) can be obtained by coagulating the latex according to a conventional method such as mixing with an aqueous calcium solution, an aqueous sodium chloride solution, or an aqueous ammonium sulfate solution, and drying the obtained coagulated product. .

The molecular weight of the acrylic rubber polymer obtained by the acrylic rubber production method of the present embodiment can be adjusted by the reaction time and the amount of living radical polymerization initiator (organic tellurium compound). For example, the weight average molecular weight of the acrylic rubber polymer is preferably 1,000,000 to 4,000,000, and the molecular weight distribution (Mw / Mn) is 1.3 to 3.0, more preferably It is adjusted to 1.4 to 2.9.

In the method for producing acrylic rubber of the present embodiment, a copolymer can be obtained by using two or more kinds of radical polymerizable monomers. For example, a random copolymer can be obtained by allowing two or more radically polymerizable monomers to simultaneously exist in the polymerization reaction system. Further, in the method for producing acrylic rubber according to the present embodiment, since the polymerization reaction proceeds with living properties, a block copolymer can be obtained by sequentially reacting two or more kinds of radical polymerizable monomers. it can.

It should be noted that the molecular weight of the rubber polymer is not limited to the polymer of acrylic rubber, but theoretically increases if the amount of the polymerization initiator is reduced. However, since the conventional acrylic rubber is produced by ordinary emulsion polymerization, a side reaction such as a termination reaction has priority, and simply reducing the polymerization initiator reduces the molecular weight to 1,000 while reducing the oligomer component. It could not be raised to over 1,000.

In contrast, as in the production method of this embodiment, in the polymerization of acrylic rubber, when the above organic tellurium compound is used as a living radical polymerization initiator and emulsion or suspension polymerization is performed, the acrylic rubber is reduced while reducing the oligomer component. The molecular weight can be 1,000,000 or more. Moreover, it is possible to obtain an acrylic rubber that improves the tensile strength while maintaining the elongation of the rubber cross-linked product.

In other words, by using the acrylic rubber production method of the present embodiment, the amount of polymerization initiator added can be reduced, and the tensile strength of the crosslinked rubber can be improved without reducing the elongation of the crosslinked rubber. be able to.

<Acrylic rubber composition>
The acrylic rubber composition according to this embodiment contains an acrylic rubber and a crosslinking agent.

The acrylic rubber described above can be used as the acrylic rubber included in the acrylic rubber composition of the present embodiment.

The cross-linking agent used in the present embodiment is not particularly limited as long as it can cross-link the above-described acrylic rubber, and can be appropriately selected depending on the type of cross-linkable monomer contained in the above-described acrylic rubber. Examples of such a crosslinking agent include polyvalent amine compounds such as diamine compounds, and carbonates thereof; sulfur; sulfur donors; triazine thiol compounds; polyvalent epoxy compounds; organic carboxylic acid ammonium salts; A dithiocarbamic acid metal salt; a polyvalent carboxylic acid; a quaternary onium salt; an imidazole compound; an isocyanuric acid compound; These crosslinking agents may be used alone or in combination of two or more.

When the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having an epoxy group, an aliphatic polyvalent amine compound such as hexamethylene diamine or hexamethylene diamine carbamate, and its Carbonates; aromatic polyvalent amine compounds such as 4,4′-methylenedianiline; ammonium carboxylates such as ammonium benzoate and ammonium adipate; metal salts of dithiocarbamate such as zinc dimethyldithiocarbamate; tetradecanoic acid and the like It is preferable to use a polyvalent carboxylic acid; a quaternary onium salt such as cetyltrimethylammonium bromide; an imidazole compound such as 2-methylimidazole; an isocyanuric acid compound such as ammonium isocyanurate;

When the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having a halogen group, it is preferable to use sulfur, a sulfur donor, a triazine thiol compound, or the like as the crosslinker.

Specific examples of the sulfur donor include dipentamethylene thiuram hexasulfide and triethyl thiuram disulfide.

Specific examples of the triazine thiol compound include 1,3,5-triazine-2,4,6-trithiol, 6-anilino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1, 3,5-triazine-2,4-dithiol, 6-diallylamino-1,3,5-triazine-2,4-dithiol, and 6-octylamino-1,3,5-triazine-2,4-dithiol Among these, 1,3,5-triazine-2,4,6-trithiol is preferable among these.

When the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having a carboxyl group, it is preferable to use a polyvalent amine compound and a carbonate thereof, or a guanidine compound as a crosslinking agent. .

The polyvalent amine compound and carbonate thereof are not particularly limited, but polyvalent amine compounds having 4 to 30 carbon atoms and carbonates thereof are preferred. Examples of such polyvalent amine compounds and carbonates thereof include aliphatic polyvalent amine compounds, carbonates thereof, and aromatic polyvalent amine compounds.

The aliphatic polyvalent amine compound and the carbonate thereof are not particularly limited, and examples thereof include hexamethylene diamine, hexamethylene diamine carbamate, and N, N′-dicinnamylidene-1,6-hexanediamine. Among these, hexamethylenediamine carbamate is preferable.

The aromatic polyvalent amine compound is not particularly limited. For example, 4,4′-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether 4,4 ′-(m-phenylenediisopropylidene) dianiline, 4,4 ′-(p-phenylenediisopropylidene) dianiline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, Examples include 4,4′-diaminobenzanilide, 4,4′-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3,5-benzenetriamine. Among these, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane is preferable.

The content of the crosslinking agent in the acrylic rubber composition of the present embodiment is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the acrylic rubber in the acrylic rubber composition. Particularly preferred is 0.2 to 7 parts by weight. When there is too little content of a crosslinking agent, bridge | crosslinking will become inadequate and there exists a possibility that the shape maintenance of an acrylic rubber crosslinked material may become difficult. On the other hand, when there is too much content of a crosslinking agent, acrylic rubber crosslinked material will become hard too much and elongation may fall.

The acrylic rubber composition of the present embodiment can contain a crosslinking accelerator in addition to the crosslinking agent. The crosslinking accelerator is not particularly limited. For example, when the above-mentioned crosslinking monomer is a crosslinking monomer having an epoxy group, and the crosslinking agent is a metal salt of dithiocarbamate, crosslinking promotion is performed. As the agent, other dithiocarbamic acid metal salts other than the dithiocarbamic acid metal salt used as the crosslinking agent are used.

In addition, when the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having a halogen group and the crosslinking agent is sulfur or a sulfur donor, the crosslinking accelerator may be a fatty acid metal. Soap is preferably used. When the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having a halogen group and the crosslinker is a triazine thiol compound, dithiocarbamate and its derivatives are used as the crosslink accelerator. Thiourea compounds, thiuram sulfide compounds and the like are used.

Further, when the crosslinkable monomer contained in the acrylic rubber is a crosslinkable monomer having a carboxyl group, and the crosslinking agent is a polyvalent amine compound or a carbonate thereof, as a crosslinking accelerator Aliphatic monovalent secondary amine compounds, aliphatic monovalent tertiary amine compounds, guanidine compounds, imidazole compounds, quaternary onium salts, tertiary phosphine compounds, alkali metal salts of weak acids, diazabicycloalkene compounds, etc. Is used.

These crosslinking accelerators may be used alone or in combination of two or more.

The amount of the crosslinking accelerator used is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, particularly preferably 0.3 to 100 parts by weight based on 100 parts by weight of the acrylic rubber in the acrylic rubber composition. 10 parts by weight. If the amount of the crosslinking accelerator is too large, the crosslinking rate may become too fast during crosslinking, the crosslinking accelerator may bloom on the surface of the crosslinked product (or blooming), or the crosslinked product may become too hard. When there are too few crosslinking accelerators, the tensile strength of a crosslinked material may fall remarkably.

Moreover, in the acrylic rubber composition according to the present embodiment, in addition to the above components, a compounding agent generally used in the field of acrylic rubber can be used. Such a compounding agent is a compounding agent such as a crosslinking activator, a filler, a lubricant, an anti-aging agent, an antioxidant, a scorch inhibitor, a process oil, a plasticizer, and the like. Can be blended.

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. Of these, furnace black is preferably used, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, MAF, FEF and the like. It is done. Specific examples of graphite include natural graphite such as scaly graphite and scaly graphite, and artificial graphite. In addition, the carbonaceous material mentioned above can be used individually or in combination of 2 or more types, respectively.

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 such as glass fibers (milled fibers), carbon fibers, aramid fibers, and potassium titanate whiskers; silica, mica; These fillers are used alone or in combination of two or more.

Examples of the lubricant include hydrocarbon wax such as paraffin wax; fatty acid wax such as stearin; fatty acid ester wax such as polyhydric alcohol fatty acid ester and saturated fatty acid ester (ester wax); higher alcohol A fatty alcohol wax; and the like. One of these lubricants may be used alone, or two or more thereof may be used in combination.

As the anti-aging agent, for example, an anti-aging agent such as phenol, amine or phosphoric acid can be used. Typical examples of phenolic groups include 2,2-methylenebis (4-methyl-6-tert-butylphenol), and typical examples of amine series include 4,4- (α, α-dimethylbenzyl) diphenylamine. Is mentioned. One of these anti-aging agents may be used alone, or two or more thereof may be used in combination.

Examples of the antioxidant include amine-based antioxidants, phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the scorch inhibitor include organic acid scorch inhibitors such as phthalic anhydride, benzoic acid, salicylic acid and malic acid; nitroso compound scorch inhibitors such as N-nitrosodiphenylamine; and N- (cyclohexylthio) phthalimide. Thiophthalimide-based scorch inhibitor; sulfonamide derivative; 2-mercaptobenzimidazole; trichloromelamine; Among these, a sulfonamide derivative is preferable. The scorch inhibitor may be used alone or in combination of two or more.

As process oil, for example, mineral oil or synthetic oil may be used. As the mineral oil, aroma oil, naphthenic oil, paraffin oil and the like can be used.

Examples of the plasticizer include trimellitic acid plasticizer, pyromellitic acid plasticizer, ether ester plasticizer, polyester plasticizer, phthalic acid plasticizer, adipate ester plasticizer, and phosphoric ester plasticizer. Agents, sebacic acid ester plasticizers, alkylsulfonic acid ester compound plasticizers, epoxidized vegetable oil plasticizers, and the like can be used.

Specific examples of plasticizers include trimellitic acid tri-2-ethylhexyl, trimellitic acid isononyl ester, trimellitic acid mixed linear alkyl ester, dipentaerythritol ester, pyromellitic acid 2-ethylhexyl ester, polyether ester ( Molecular weight of about 300-5000), bis [2- (2-butoxyethoxy) ethyl] adipate, dioctyl adipate, polyester of adipic acid (molecular weight of about 300-5000), dioctyl phthalate, diisononyl phthalate, dibutyl phthalate Tricresyl phosphate, dibutyl sebacate, phenyl sulfonic acid phenyl ester, epoxidized soybean oil, diheptanoate, di-2-ethylhexanoate, didecanoate and the like. These can be used alone or in combination of two or more.

Further, the acrylic rubber composition of the present embodiment may be blended with a polymer such as rubber, elastomer, resin other than the acrylic rubber of the present embodiment, if necessary.

As a method for preparing the acrylic rubber composition of the present embodiment, a mixing method such as roll mixing, Banbury mixing, screw mixing, solution mixing, or the like can be appropriately employed. The blending order is not particularly limited, but after sufficiently mixing components that are not easily reacted or decomposed by heat, components that are easily reacted by heat or components that are easily decomposed (for example, crosslinking agents, crosslinking accelerators, etc.) What is necessary is just to mix for a short time at the temperature which does not decompose | disassemble.

The acrylic rubber composition according to the present embodiment thus obtained can improve the tensile strength while maintaining the elongation of the crosslinked rubber by crosslinking.

<Cross-linked acrylic rubber>
The crosslinked acrylic rubber according to this embodiment is formed by crosslinking the above-mentioned acrylic rubber composition.

Crosslinking is performed by heating the acrylic rubber composition. The crosslinking conditions are such that the crosslinking temperature is preferably 130 to 220 ° C., more preferably 140 to 200 ° C., and the crosslinking time is preferably 30 seconds to 10 hours, more preferably 1 minute to 5 hours. This first-stage crosslinking is also referred to as primary crosslinking.

As a molding method for obtaining a crosslinked acrylic rubber having a desired shape, molding methods such as extrusion molding, injection molding, transfer molding, and compression molding can be employed. Further, it can be heated simultaneously with molding to be crosslinked.

General rubber processing procedures can be used for extrusion molding. That is, a rubber composition prepared by roll mixing or the like is supplied to a feed port of an extruder, and is softened by heating from a barrel in the process of being sent to a head portion with a screw. Then, by passing the softened rubber composition through a die having a predetermined shape provided in the head portion, a long extruded product (plate, bar, pipe, hose, deformed product, etc.) having a target cross-sectional shape is obtained. obtain.

In injection molding, transfer molding, and compression molding, a mold cavity having a shape corresponding to one or several products can be filled with the acrylic rubber composition of the present embodiment for shaping. Then, by heating the mold, shaping and crosslinking can be performed almost simultaneously.

Further, in addition to the above-mentioned primary crosslinking, if necessary, the acrylic rubber crosslinked product is heated at 130 ° C. to 220 ° C., more preferably 140 ° C. to 200 ° C. in an oven using electricity, hot air, steam or the like as a heat source. Secondary crosslinking can be performed by heating for 1 to 48 hours.

The thus obtained acrylic rubber cross-linked product of the present embodiment has high tensile strength while maintaining the elongation and compression set resistance as the acrylic rubber cross-linked product. Therefore, the crosslinked acrylic rubber of the present embodiment can be suitably used for, for example, automotive parts (for example, O-rings, seals, gaskets, hoses) that come into contact with fuel oil, engine oil, or the like.

Hereinafter, the present embodiment will be described more specifically with reference to examples. In the following, “parts” and “%” are based on weight unless otherwise specified. However, this embodiment is not limited only to these examples. Each characteristic was measured and evaluated as follows.

<Molecular weight>
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic rubber were measured by gel permeation chromatography (GPC). In the measurement by GPC, “HLC-8320” manufactured by Tosoh Corp. was used as a measuring device and “supermultipore HZ-H” manufactured by Tosoh Corp. was connected in series as a column. Measurement by GPC was performed under the conditions of column size: 4.6 mm ID × 15 cm, eluent: tetrahydrofuran, column temperature: 40 ° C. In the measurement by GPC, a differential refractometer (manufactured by Tosoh Corporation, RI-8320) was used as a detector. In addition, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured as polystyrene conversion values.

<Molecular weight distribution>
From the above-mentioned weight average molecular weight (Mw) and number average molecular weight (Mn), the molecular weight distribution (Mw / Mn) of the acrylic rubber was calculated.

<Oligomer amount>
The oligomer amount was measured as the content ratio (%) of the composition having a weight average molecular weight of 100,000 or less including the oligomer in the acrylic rubber.

<Normal properties (tensile strength, elongation, hardness)>
The acrylic 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 pressed at 170 ° C. for 20 minutes while being pressed at a press pressure of 10 MPa to obtain a sheet-like acrylic rubber crosslinked product. . Next, the obtained sheet-like acrylic rubber crosslinked product was put in a gear type oven and heat-treated at 170 ° C. for 4 hours. A test piece was prepared by punching out the sheet-like acrylic rubber crosslinked product after heat treatment with a dumbbell type 3 type. Next, using this test piece, according to JIS K6251, tensile strength (MPa) and elongation (%), and according to JIS K6253, using a durometer hardness tester (type A), It was measured.

<Compression set resistance>
The acrylic rubber cross-linked product is molded and cross-linked by pressing at 170 ° C. for 20 minutes to produce a cylindrical test piece having a diameter of 29 mm and a thickness of 12.5 mm, and further heated at 170 ° C. for 4 hours for secondary cross-linking. I let you. According to JIS K6262, the test piece after secondary crosslinking obtained above was allowed to stand in an environment of 175 ° C. for 70 hours while being compressed at 25%, and then the compression was released and the compression set was measured. It shows that it is excellent in compression set resistance property, so that the value of a compression set rate is small.

<Synthesis example>
(Synthesis Example 1) Synthesis of ethyl 2-methyl-2-phenylterranylpropionate In a 300 mL three-necked flask under nitrogen atmosphere, 11.48 g (90 mmol) of metal tellurium (manufactured by Aldrich, the same shall apply hereinafter) was added to 86 ml of THF. Suspended. The resulting suspension was cooled to 0 ° C. with stirring. While continuing to stir and cool the suspension, 96.4 ml (94.5 mmol) of phenyllithium (0.98 M cyclohexane-diethyl ether solution, manufactured by Kanto Chemical Co., Ltd., the same shall apply hereinafter) was added to this suspension over 10 minutes. And dripped. After completion of dropping, the contents in the three-necked flask were stirred at room temperature (25 ° C.) for 20 minutes to obtain a reaction solution in which metal tellurium completely disappeared.

The obtained reaction solution was cooled to 0 ° C. with stirring. While continuing to stir and cool the reaction solution, 18.45 g (94.5 mmol) of ethyl-2-bromoisobutyrate (manufactured by Tokyo Chemical Industry Co., Ltd., the same shall apply hereinafter) was added to the reaction solution. The reaction was continued by stirring the contents in the three-necked flask for 2 hours, and the reaction solution was returned to room temperature.

The resulting reaction solution was washed successively with degassed water, degassed saturated NH ₄ Cl aqueous solution, and degassed saturated NaCl aqueous solution. Subsequently, anhydrous magnesium sulfate was added to the organic layer (washed reaction solution), dried, and then filtered through Celite in a nitrogen atmosphere. The filtrate was concentrated under reduced pressure, and then the concentrate was distilled under reduced pressure to obtain 13.4 g (yield 51%) of ethyl 2-methyl-2-phenylterranylpropionate as a yellow oil. .

The ¹ H-NMR data of the obtained ethyl 2-methyl-2-phenylterranyl propionate are shown below.
¹ H-NMR (500 MHz, CDCl ₃ , TMS, δ ppm) 1.18 (t, J = 7.2 Hz, 3H), 1.73 (s, 6H), 4.07 (q, J = 7.2 Hz, 2H), 7.26-7.30 (m, 2H), 7.39-7.43 (m, 1H), 7.88-7.90 (m, 2H).

(Synthesis Example 2) Synthesis of 3-methylterranyl-1-propene Methyllithium (1.10 M diethyl ether solution, manufactured by Kanto Chemical Co., Ltd., the same applies below) 86.0 ml (94.5 mmol) was used instead of phenyllithium. The reaction and purification were carried out in the same manner as in Synthesis Example 1 except that 11.4 g (94.5 mmol) of allyl bromide (manufactured by Tokyo Chemical Industry Co., Ltd., the same shall apply hereinafter) was used instead of ethyl-2-bromoisobutyrate. As a yellow oily substance, 6.55 g (yield 40%) of 3-methylterranyl-1-propene was obtained.

The ¹ H-NMR data of the obtained 3-methylterranyl-1-propene is shown below.
¹ H-NMR (500 MHz, CDCl ₃ , TMS, δ ppm) 1.85 (s, 3H), 3.31 (d, J = 8.5 Hz, 2H), 4.80 (d, J = 9.0 Hz, 1H), 4.85 (d, J = 17.0 Hz, 1H), 5.90-5.99 (m, 1H).

<Production example>
(Production Example 1) Production of acrylic rubber A In a polymerization reactor equipped with a thermometer and a stirrer, 200 parts of water, 2 parts of sodium dodecyl sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.), 98.3 parts of ethyl acrylate, fumaric acid 1.7 parts of mono n-butyl was charged, and degassing under reduced pressure and nitrogen substitution were performed three times to sufficiently remove oxygen. Thereafter, 0.016 part of azobis (isobutyronitrile) and 0.021 part of ethyl-2-methyl-2-phenylterranylpropionate (Synthesis Example 1) were added and suspension polymerization was performed at 50 ° C. under normal pressure. The reaction was continued for 13 hours, and polymerization was carried out until the polymerization conversion reached 89%. The obtained suspension polymerization solution was coagulated with a calcium chloride solution, washed with water and dried to obtain acrylic rubber A. The resulting acrylic rubber A had a weight average molecular weight (Mw) of 1,303,000 and a molecular weight distribution (Mw / Mn) of 1.49. The oligomer amount (%) was 1.0%.

(Production Example 2) Production of acrylic rubber B 0.0083 parts instead of 0.016 parts azobis (isobutyronitrile), 0 instead of 0.021 parts ethyl-2-methyl-2-phenylterranylpropionate Acrylic rubber B was obtained in the same manner as in Production Example 1 except that .0089 parts were reacted for 17 hours and polymerized until the polymerization conversion reached 83%. The resulting acrylic rubber B had a weight average molecular weight (Mw) of 2,360,000 and a molecular weight distribution (Mw / Mn) of 2.08. The amount of oligomer was 0.9%.

(Production Example 3) Production of acrylic rubber C 0.0064 parts instead of 0.016 parts of azobis (isobutyronitrile), 0 instead of 0.021 parts of ethyl-2-methyl-2-phenylterranylpropionate Acrylic rubber C was obtained in the same manner as in Production Example 1 except that .0070 parts were used and reacted for 19 hours and polymerized until the polymerization conversion reached 89%. The resulting acrylic rubber C had a weight average molecular weight (Mw) of 3,505,000 and a molecular weight distribution (Mw / Mn) of 2.54. The oligomer amount was 1.6%.

(Production Example 4) Production of acrylic rubber D 48.3 parts of ethyl acrylate and 50 parts of n-butyl acrylate instead of 98.3 parts of ethyl acrylate, 0 instead of 0.016 parts of azobis (isobutyronitrile) .0071 parts, except that 0.0070 parts of ethyl-2-methyl-2-phenylterranylpropionate was used instead of 0.021 parts, reacted for 21 hours, and polymerized until the polymerization conversion reached 80%. Acrylic rubber D was obtained in the same manner as in Production Example 1. The resulting acrylic rubber D had a weight average molecular weight (Mw) of 3,098,000 and a molecular weight distribution (Mw / Mn) of 2.46. The amount of oligomer was 1.2%.

(Production Example 5) Production of acrylic rubber E 98.5 parts instead of 98.3 parts of ethyl acrylate, 1.5 parts of glycidyl methacrylate instead of 1.7 parts of mono n-butyl fumarate, azobis (isobutyrate (Ronitrile) 0.0051 part instead of 0.016 part, 3-methylterranyl-1-propene instead of 0.021 part of ethyl-2-methyl-2-phenylterranylpropionate (Synthesis Example 2) 0.0051 Acrylic rubber E was obtained in the same manner as in Production Example 1, except that the reaction was carried out for 18 hours and polymerization was carried out until the polymerization conversion reached 78%. The resulting acrylic rubber E had a weight average molecular weight (Mw) of 1,930,000 and a molecular weight distribution (Mw / Mn) of 1.61. Moreover, the oligomer amount was 2.2%.

(Production Example 6) Production of acrylic rubber F Instead of 98.3 parts of ethyl acrylate, 48.3 parts of ethyl acrylate, 30 parts of n-butyl acrylate, 20 parts of 2-methoxyethyl acrylate, mono-n-fumarate -1.7 parts vinyl chloroacetate instead of 1.7 parts butyl, 0.0062 parts 4,4'-azobis (4-cyanovaleric acid) instead of 0.016 parts azobis (isobutyronitrile), ethyl Instead of 0.021 part of -2-methyl-2-phenylterranylpropionate, 0.0020 part of 3-methylterranyl-1-propene (Synthesis Example 2) and 0.029 part of methacrylic acid were reacted in advance at room temperature for 1 hour. Acrylic rubber F was obtained in the same manner as in Production Example 1 except that the macroinitiator was used and reacted for 20 hours and polymerized until the polymerization conversion reached 85%. The resulting acrylic rubber F had a weight average molecular weight (Mw) of 2,682,000 and a molecular weight distribution (Mw / Mn) of 2.39. Moreover, the oligomer amount was 2.4%.

(Production Example 7) Production of acrylic rubber G In a polymerization reactor equipped with a thermometer and a stirrer, water 200 parts, sodium dodecyl sulfate 2 parts, ethyl acrylate 98.3 parts, mono n-butyl fumarate 1.7 The oxygen was sufficiently removed by performing vacuum degassing and nitrogen replacement twice. Thereafter, 0.005 part of cumene hydroperoxide and 0.002 part of sodium formaldehydesulfoxylate are added, and under the normal pressure, emulsion polymerization is started at a temperature of 20 ° C., the reaction is allowed to proceed for 5 hours, and polymerization is carried out until a polymerization conversion rate reaches 95%. did. An acrylic rubber G was obtained using the obtained suspension polymerization solution in the same manner as in Production Example 1. The resulting acrylic rubber G had a weight average molecular weight (Mw) of 849,000 and a molecular weight distribution (Mw / Mn) of 3.18. The amount of oligomer was 6.8%.

(Production Example 8) Production of acrylic rubber H 0.035 parts instead of 0.016 parts azobis (isobutyronitrile), 0 instead of 0.021 parts ethyl-2-methyl-2-phenylterranyl propionate Acrylic rubber H was obtained in the same manner as in Production Example 1 except that 0.045 part was reacted for 6 hours and polymerized until the polymerization conversion reached 81%. The resulting acrylic rubber H had a weight average molecular weight (Mw) of 638,000 and a molecular weight distribution (Mw / Mn) of 1.29. The amount of oligomer was 0.6%.

(Production Example 9) Production of acrylic rubber I An acrylic rubber I was prepared in the same manner as in Production Example 7 except that 48.3 parts of ethyl acrylate and 50 parts of n-butyl acrylate were used instead of 98.3 parts of ethyl acrylate. Rubber I was obtained. The resulting acrylic rubber I had a weight average molecular weight (Mw) of 1,145,000 and a molecular weight distribution (Mw / Mn) of 2.93. The amount of oligomer was 5.3%.

(Production Example 10) Production of acrylic rubber J Except for using 98.5 parts of ethyl acrylate in place of 98.5 parts and 1.5 parts of glycidyl methacrylate in place of 1.7 parts of mono n-butyl fumarate. In the same manner as in Production Example 7, an acrylic rubber J was obtained. The resulting acrylic rubber J had a weight average molecular weight (Mw) of 704,000 and a molecular weight distribution (Mw / Mn) of 2.38. Moreover, the oligomer amount was 6.1%.

(Production Example 11) Production of acrylic rubber K Instead of 98.3 parts of ethyl acrylate, 48.3 parts of ethyl acrylate, 30 parts of n-butyl acrylate and 20 parts of 2-methoxyethyl acrylate, mono-n-fumarate An acrylic rubber K was obtained in the same manner as in Production Example 7, except that 1.7 parts of vinyl chloroacetate was used instead of 1.7 parts of butyl. The resulting acrylic rubber K had a weight average molecular weight (Mw) of 1,253,000 and a molecular weight distribution (Mw / Mn) of 3.15. Moreover, the oligomer amount was 8.4%.

<Examples and Comparative Examples>
Example 1
Using a Banbury mixer, 50 parts of FEF carbon black (trade name “Seast SO”, manufactured by Tokai Carbon Co., Ltd., “Seast” is a registered trademark) is added to 100 parts of acrylic rubber A obtained in Production Example 1, stearic acid 2 parts, ester wax (trade name “Greg G-8205”, manufactured by Dainippon Ink & Chemicals, lubricant), 1 part, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine (trade name: NOCRACK CD) , Manufactured by Ouchi Shinsei Chemical Co., Ltd., an anti-aging agent, “NOCRACK” is a registered trademark) and 2 parts were added and mixed at 80 ° C. for 5 minutes. Subsequently, the obtained mixture was transferred to a roll at 50 ° C., and 0.78 part of hexamethylenediamine carbamate (trade name: Diak # 1, manufactured by DuPont Elastomer Co., Ltd.) and 1,3-di-o-tolyl A crosslinkable rubber composition (acrylic rubber) was prepared by blending and kneading 2 parts of guanidine (trade name: Noxeller DT, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., crosslinking accelerator, “Noxeller” is a registered trademark, the same applies hereinafter). Composition) was obtained. Using the obtained acrylic rubber composition, a test piece (acrylic rubber cross-linked product) was obtained by the above-described method, and normal properties (tensile strength, elongation, hardness) and compression set were measured and evaluated. went. The results are shown in Table 1A.

(Example 2)
An acrylic rubber composition was prepared in the same manner as in Example 1 except that the acrylic rubber B obtained in Production Example 2 was used in place of the acrylic rubber A, to obtain an acrylic rubber crosslinked product. Evaluation was performed. The results are shown in Table 1A.

(Example 3)
Except that the acrylic rubber C obtained in Production Example 3 was used in place of the acrylic rubber A, an acrylic rubber composition was prepared in the same manner as in Example 1 to obtain an acrylic rubber crosslinked product, which was measured in the same manner. Evaluation was performed. The results are shown in Table 1A.

Example 4
Example except that the acrylic rubber D obtained in Production Example 4 was used in place of the acrylic rubber A, the addition amount of FEF carbon black was 60 parts, and the addition amount of hexamethylenediamine carbamate was 0.6 parts. In the same manner as in Example 1, an acrylic rubber composition was prepared to obtain a crosslinked acrylic rubber, and the measurement and evaluation were performed in the same manner. The results are shown in Table 1A.

(Example 5)
The acrylic rubber E obtained in Production Example 5 was used in place of the acrylic rubber A, and ammonium benzoate (trade name: Balnock AB-S, instead of hexamethylenediamine carbamate and 1,3-di-o-tolylguanidine was used. An acrylic rubber composition was prepared in the same manner as in Example 1 except that 1.1 parts of Ouchi Shinsei Chemical Co., Ltd., cross-linking agent, “Barnock” was a registered trademark), and no ester wax was used. It prepared and obtained acrylic rubber crosslinked material, and measured and evaluated similarly. The results are shown in Table 1B.

(Example 6)
The acrylic rubber F obtained in Production Example 6 was used in place of the acrylic rubber A, the amount of FEF carbon black added was 60 parts, and 1 instead of hexamethylenediamine carbamate and 1,3-di-o-tolylguanidine was used. , 3,5-triazine trithiol (trade name: ZISNET-F, manufactured by Sanyo Kasei Co., Ltd., cross-linking agent, “ZISNET” is a registered trademark) 1.5 parts by chemical industry, cross-linking accelerator), 0.3 parts by diethylthiourea (trade name: Noxeller EUR, made by Ouchi Shinsei Chemical Co., Ltd.), and N- (cyclohexylthio) phthalimide (product) Name: Retarder CTP, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., scorch inhibitor) The composition was prepared to give an acrylic cross-linked rubber, similarly measured and evaluated. The results are shown in Table 1B.

(Example 7)
In the same manner as in Example 4, except that the amount of FEF carbon black added was 80 parts and 20 parts of a polyether ester plasticizer (trade name: Adeka Sizer RS735, plasticizer manufactured by Adeka) was further used. A rubber composition was prepared, an acrylic rubber cross-linked product was obtained, and measured and evaluated in the same manner. The results are shown in Table 1B.

(Comparative Example 1)
An acrylic rubber composition was prepared in the same manner as in Example 1 except that the acrylic rubber G obtained in Production Example 7 was used in place of the acrylic rubber A obtained in Production Example 1, and an acrylic rubber crosslinked product was prepared. Obtained and similarly measured and evaluated. The results are shown in Table 1A.

(Comparative Example 2)
An acrylic rubber composition was prepared in the same manner as in Example 1 except that the acrylic rubber H obtained in Production Example 8 was used instead of the acrylic rubber A obtained in Production Example 1, and an acrylic rubber crosslinked product was prepared. Obtained and similarly measured and evaluated. The results are shown in Table 1A.

(Comparative Example 3)
An acrylic rubber composition was prepared in the same manner as in Example 4 except that the acrylic rubber I obtained in Production Example 9 was used in place of the acrylic rubber D obtained in Production Example 4, and an acrylic rubber crosslinked product was prepared. Obtained and similarly measured and evaluated. The results are shown in Table 1A.

(Comparative Example 4)
An acrylic rubber composition was prepared in the same manner as in Example 5 except that the acrylic rubber J obtained in Production Example 10 was used instead of the acrylic rubber E obtained in Production Example 5, and an acrylic rubber crosslinked product was prepared. Obtained and similarly measured and evaluated. The results are shown in Table 1B.

(Comparative Example 5)
An acrylic rubber composition was prepared in the same manner as in Example 6 except that the acrylic rubber K obtained in Production Example 11 was used in place of the acrylic rubber F obtained in Production Example 6, and an acrylic rubber crosslinked product was obtained. Obtained and similarly measured and evaluated. The results are shown in Table 1B.

(Comparative Example 6)
An acrylic rubber composition was prepared in the same manner as in Example 7 except that the acrylic rubber I obtained in Production Example 9 was used in place of the acrylic rubber D obtained in Production Example 4, and an acrylic rubber crosslinked product was obtained. Obtained and similarly measured and evaluated. The results are shown in Table 1B.

As shown in Table 1A and Table 1B, it contains an acrylate monomer and a structural unit derived from a crosslinkable monomer having a crosslinkable group in the side chain, and has a weight average molecular weight of 1,000,000 to 4 The crosslinked acrylic rubber (Examples 1 to 7) adjusted to 1,000,000 and the amount of oligomer adjusted to 5% or less (Examples 1 to 7) have high tensile strength while maintaining elongation and compression set resistance. Met.

Also, by increasing the amount of filler (carbon black) added to the acrylic rubber composition, the compression set resistance of the crosslinked acrylic rubber was further improved (Example 7).

The embodiments of the present embodiment have been described with reference to examples. However, the present embodiments are not limited to specific embodiments and examples, and are within the scope of the invention described in the claims. Various modifications and changes are possible.

This international application claims priority based on Japanese Patent Application No. 2016-250179 filed on December 22, 2016, the entire contents of which are hereby incorporated by reference.

Claims

It has an acrylic ester monomer unit and a structural unit derived from a crosslinkable monomer,
The weight average molecular weight is 1,000,000 to 4,000,000,
An acrylic rubber having an oligomer amount of 5% or less.
2. The acrylic rubber according to claim 1, having a molecular weight distribution of 1.3 to 3.0.
The acrylic rubber according to claim 1 or 2, wherein the crosslinkable monomer has one or more crosslinkable groups of an epoxy group, a halogen group, and a carboxyl group in a side chain.
An acrylic rubber composition containing the acrylic rubber according to any one of claims 1 to 3 and a crosslinking agent.
A crosslinked acrylic rubber product obtained by crosslinking the acrylic rubber composition according to claim 4.
A process for producing acrylic rubber, in which an acrylic ester monomer and a crosslinkable monomer having a crosslinkable group in the side chain are copolymerized by emulsion polymerization or suspension polymerization in the presence of a living radical polymerization initiator.
The method for producing acrylic rubber according to claim 6, wherein the living radical polymerization initiator is an organic tellurium compound.
The method for producing an acrylic rubber according to claim 7, wherein the organic tellurium compound is represented by the following general formula (1).

(Wherein R 1 represents an alkyl group, an unsubstituted or substituted cycloalkyl group, an unsubstituted or substituted aryl group or an unsubstituted or substituted aromatic heterocyclic group, and R 2 and R 3 each independently represent hydrogen An atom or an alkyl group, and R 4 represents an unsubstituted or substituted vinyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted aromatic heterocyclic group, an acyl group, a hydrocarbyloxycarbonyl group, or a cyano group.
Furthermore, the manufacturing method of the acrylic rubber of any one of Claim 6 thru | or 8 which performs the said emulsion polymerization or the said suspension polymerization in presence of the compound represented by a radical generator or following General formula (2). .

(Wherein R 5 and R 6 each independently represents an alkyl group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted aromatic heterocyclic group)