WO2018079784A1 - Acrylic rubber and method for producing same - Google Patents

Abstract

Provided is an acrylic rubber containing a lubricant, the lubricant being at least one selected from among phosphate ester, fatty acid ester, fatty acid amide, and higher fatty acid. According to the present invention, an acrylic rubber which has excellent handleability when dried, and has excellent roll processability can be provided.

Description

Acrylic rubber and method for producing the same

The present invention relates to an acrylic rubber and a method for producing the same, and more particularly relates to an acrylic rubber excellent in handleability during drying and roll processability, and a method for producing such an acrylic rubber.

Acrylic rubber is a polymer mainly composed of an acrylate ester and is generally known as a rubber excellent in heat resistance, oil resistance and ozone resistance, and is widely used in fields related to automobiles.

Such an acrylic rubber is usually obtained by emulsion polymerization of a monomer mixture constituting the acrylic rubber, coagulating the resulting emulsion polymerization solution by adding a coagulant, and drying the hydrous crumb obtained by coagulation. (See, for example, Patent Document 1). For drying the hydrous crumb, a hot air dryer is usually used, but from the viewpoint of productivity, a drying device such as a belt conveyor type band dryer capable of drying in a continuous process is used. On the other hand, in the drying of such acrylic rubber, there is a problem that the acrylic rubber is softened by the temperature at the time of drying and adheres to the wall surface or the like of the drying device, thereby reducing operability. Furthermore, the conventional acrylic rubber such as the acrylic rubber described in Patent Document 1 is likely to stick to the roll when various compounding agents are blended using the roll, and the workability when processing with the roll is high. There was also a problem that it was not enough.

JP 7-145291 A

The present invention has been made in view of such a situation, and an object thereof is to provide an acrylic rubber excellent in handleability during drying and roll processability, and a method for producing the same. Another object of the present invention is to provide an acrylic rubber composition using such an acrylic rubber and a rubber cross-linked product.

As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by including a specific lubricant in acrylic rubber, and the present invention has been completed.

That is, according to the present invention, there is provided an acrylic rubber containing at least one lubricant selected from phosphoric acid esters, fatty acid esters, fatty acid amides, and higher fatty acids.
The lubricant preferably contains at least one selected from a phosphate ester and a higher fatty acid, and more preferably contains polyoxyethylene higher alcohol phosphoric acid or a fatty acid having 12 to 20 carbon atoms.
The content of the lubricant is preferably from 0.1 to 0.4% by weight, more preferably from 0.2 to 0.3% by weight.
The acrylic rubber of the present invention preferably has an acrylic rubber component content of 95% by weight or more.
The acrylic rubber is preferably an acrylic rubber containing a carboxyl group.

According to the present invention, there are provided an acrylic rubber composition containing the acrylic rubber and a crosslinking agent, and a crosslinked rubber product obtained by crosslinking such an acrylic rubber composition.

In addition, according to the present invention, there is provided a method for producing the acrylic rubber, wherein the monomer for forming the acrylic rubber is subjected to emulsion polymerization, and an emulsion polymerization step for obtaining an emulsion polymerization solution and coagulation are performed. A method for producing an acrylic rubber, comprising: a lubricant adding step for containing the lubricant in the previous emulsion polymerization solution; and a coagulation step for obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization solution and solidifying the emulsion polymerization solution. Is provided.
Alternatively, according to the present invention, there is provided a method for producing the acrylic rubber, wherein the monomer for forming the acrylic rubber is mixed with an emulsifier and water to obtain a monomer emulsion. A preparation step, a lubricant addition step in which a lubricant is added to the monomer emulsion prepared in the emulsion preparation step, and a monomer contained in the monomer emulsion in which the lubricant is added in the lubricant addition step There is provided an acrylic rubber production method comprising: an emulsion polymerization step of obtaining an emulsion polymerization solution by polymerization; and a coagulation step of obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization solution and solidifying the emulsion polymerization solution. The

In the production method of the present invention, the addition amount of the lubricant in the lubricant addition step is 0.1 to 0.4 parts by weight with respect to 100 parts by weight of the acrylic rubber component contained in the emulsion polymerization liquid. It is preferably 0.2 to 0.3 parts by weight.
In the production method of the present invention, it is preferable to perform the emulsion polymerization of the monomer in the emulsion polymerization step in the presence of a nonionic emulsifier and an anionic emulsifier.
In the production method of the present invention, the nonionic emulsifier and the anionic emulsifier are preferably used in a weight ratio of nonionic emulsifier / anionic emulsifier of 50/50 to 75/25.
In the production method of the present invention, in the emulsion polymerization step, the monomer, the polymerization initiator and the reducing agent for forming the acrylic rubber are continuously added to the polymerization reaction system from the start of the polymerization reaction to an arbitrary time. It is preferable to carry out the emulsion polymerization reaction while dropping.
In the production method of the present invention, the monomer for forming the acrylic rubber is in the state of a monomer emulsion obtained by mixing an emulsifier and water, from the start of the polymerization reaction to any time, It is preferable to carry out the emulsion polymerization reaction while continuously dropping into the polymerization reaction system.

According to the present invention, an acrylic rubber excellent in handleability during drying and roll processability and a method for producing such an acrylic rubber are provided.

<Acrylic rubber>
The acrylic rubber of the present invention is a (meth) acrylic acid ester monomer [acrylic acid as a main component in the molecule (in the present invention, having 50% by weight or more in the total monomer units of rubber). An ester monomer and / or a methacrylic acid ester monomer. The same applies to methyl (meth) acrylate. ] A rubbery polymer containing units containing at least one lubricant selected from phosphoric acid esters, fatty acid esters, fatty acid amides, and higher fatty acids.

The (meth) acrylic acid ester monomer that forms the (meth) acrylic acid ester monomer unit that is the main component of the acrylic rubber of the present invention is not particularly limited. And (meth) acrylic acid alkoxyalkyl ester monomers.

The (meth) acrylic acid alkyl ester monomer is not particularly limited, but is preferably an ester of an alkanol having 1 to 8 carbon atoms and (meth) acrylic acid, specifically, methyl (meth) acrylate, ( (Meth) ethyl acrylate, (meth) acrylic acid n-propyl, (meth) acrylic acid isopropyl, (meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid n-hexyl, (meth) Examples include 2-ethylhexyl acrylate and cyclohexyl (meth) acrylate. Among these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and ethyl acrylate and n-butyl acrylate are particularly preferable. These can be used alone or in combination of two or more.

The (meth) acrylic acid alkoxyalkyl ester monomer is not particularly limited, but an ester of an alkoxyalkyl alcohol having 2 to 8 carbon atoms and (meth) acrylic acid is preferable. Specifically, (meth) acrylic acid Methoxymethyl, ethoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate , 3-methoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, and the like. Of these, 2-ethoxyethyl (meth) acrylate and 2-methoxyethyl (meth) acrylate are preferable, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferable. These can be used alone or in combination of two or more.

The content of the (meth) acrylic acid ester monomer unit in the acrylic rubber of the present invention is usually 50 to 99.9% by weight, preferably 60 to 99.5% by weight, more preferably 70 to 99.99%. 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 lowered. There is a risk that the heat resistance of the object will decrease.

In the acrylic rubber of the present invention, the (meth) acrylic acid ester monomer unit includes 30 to 100% by weight of a (meth) acrylic acid alkyl ester monomer unit and a (meth) acrylic acid alkoxyalkyl ester monomer. It is preferable to use those comprising 70 to 0% by weight of body units.

The acrylic rubber of the present invention may contain a crosslinkable monomer unit as required in addition to the (meth) acrylic acid alkyl ester monomer unit. The crosslinkable monomer that forms the crosslinkable monomer unit is not particularly limited. For example, an α, β-ethylenically unsaturated carboxylic acid monomer; a monomer having an epoxy group; a halogen atom Monomer; diene monomer; and the like.

The α, β-ethylenically unsaturated carboxylic acid monomer that forms the α, β-ethylenically unsaturated carboxylic acid monomer unit is not particularly limited, but examples thereof include α, β- having 3 to 12 carbon atoms. Ethylenically unsaturated monocarboxylic acid, α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and alkanol having 1 to 8 carbon atoms And monoesters. By using the α, β-ethylenically unsaturated carboxylic acid monomer, the acrylic rubber can be converted into a carboxyl group-containing acrylic rubber having a carboxyl group as a crosslinking point, and thus a rubber cross-linked product can be obtained. Further, the compression set resistance can be further improved.

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, and mono-n-butyl maleate; monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, maleate And butenedionic acid monoesters having an alicyclic structure such as acid monocyclohexenyl; itaconic acid monoesters such as monomethyl itaconate, monoethyl itaconate, mono n-butyl itaconate, and monocyclohexyl itaconate;
Among these, monoesters of α, β-ethylenically unsaturated dicarboxylic acids having 4 to 12 carbon atoms and alkanols having 1 to 8 carbon atoms are preferable, butenedionic acid monochain alkyl ester, or butenedione having an alicyclic structure Acid monoesters are more preferred, mono n-butyl fumarate, mono n-butyl maleate, monocyclohexyl fumarate, and monocyclohexyl maleate are more preferred, and mono n-butyl fumarate is particularly preferred. These α, β-ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. Among the above monomers, dicarboxylic acids include those that exist as anhydrides.

Although it does not specifically limit as a monomer which has an epoxy group, For example, Epoxy group containing (meth) acrylic acid ester, such as glycidyl (meth) acrylate; Epoxy group containing ethers, such as allyl glycidyl ether and vinyl glycidyl ether; Is mentioned.

Although it does not specifically limit as a monomer which has a halogen atom, For example, unsaturated alcohol ester of a 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, and 2,3-dichloropropyl (meth) acrylate.
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 and 3- (hydroxychloroacetoxy) propyl (meth) acrylate.
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 the halogen-containing unsaturated amide include N-chloromethyl (meth) acrylamide.
Specific examples of the haloacetyl group-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether and p-vinylbenzyl chloroacetate.

Examples of the diene monomer include conjugated diene monomers and non-conjugated diene monomers.
Specific examples of the conjugated diene monomer include 1,3-butadiene, isoprene, and piperylene.
Specific examples of the non-conjugated diene monomer include ethylidene norbornene, dicyclopentadiene, dicyclopentadienyl (meth) acrylate, and 2-dicyclopentadienyl ethyl (meth) acrylate. .

Among the crosslinkable monomers, when an α, β-ethylenically unsaturated carboxylic acid monomer is used, the acrylic rubber can be a carboxyl group-containing acrylic rubber. By making the acrylic rubber into a carboxyl group-containing acrylic rubber, the compression set resistance can be improved while improving the oil resistance and heat resistance, which is preferable. Moreover, as will be described later, when the acrylic rubber is a carboxyl group-containing acrylic rubber, compared to the case where a crosslinkable group other than the carboxyl group (for example, an epoxy group, a halogen atom, etc.) is introduced, Since the function and effect can be made more prominent, a carboxyl group-containing acrylic rubber is preferable also from such a viewpoint.

The content of the crosslinkable monomer unit in the acrylic rubber of the present invention is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, still more preferably 0.5 to 5% by weight. It is. By setting the content of the crosslinkable monomer unit within the above range, the compression set resistance can be more appropriately increased while the mechanical properties and heat resistance of the resulting rubber cross-linked product are improved.

In addition to the (meth) acrylic acid ester monomer unit and the crosslinkable monomer unit used as necessary, the acrylic rubber of the present invention has other monomer units copolymerizable therewith. You may do it. Such other copolymerizable monomers include aromatic vinyl monomers, α, β-ethylenically unsaturated nitrile monomers, acrylamide monomers, and other olefin monomers. Can be mentioned.

Examples of aromatic vinyl monomers include styrene, α-methylstyrene, divinylbenzene and the like.

Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.
Examples of acrylamide monomers include acrylamide and methacrylamide.
Other olefinic monomers include ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, and the like.

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

Other monomers that can be copolymerized can be used singly or in combination of two or more. The content of these copolymerizable other monomer units in the acrylic rubber of the present invention is usually 49.9% by weight or less, preferably 39.5% by weight or less, more preferably 29.5% by weight. % Or less.

The acrylic rubber of the present invention contains at least one lubricant selected from phosphoric acid esters, fatty acid esters, fatty acid amides, and higher fatty acids (hereinafter, referred to as “specific lubricant” as appropriate). Thereby, adhesiveness can be reduced appropriately and, as a result, it can be excellent in the handleability at the time of drying, and roll workability. Specifically, according to the acrylic rubber of the present invention, it is possible to effectively suppress the problem that the acrylic rubber softens due to the temperature at the time of drying and adheres to the wall surface of the drying device. The effect of effectively suppressing the decrease in operability caused by the adhesion of rubber to the wall surface of the drying device, and also the effect of suppressing the adhesion to the roll when various ingredients are blended using the roll Thus, there is an effect that it is possible to improve workability when processing with a roll. In particular, when the acrylic rubber is a carboxyl group-containing acrylic rubber, by introducing the carboxyl group, the compression set resistance can be appropriately increased, while the action of the carboxykyl group increases the tackiness. It will be. And when a carboxyl group-containing acrylic rubber is used as the acrylic rubber, it has high adhesiveness, so that it is compared with a case where a crosslinkable group other than a carboxyl group (for example, an epoxy group, a halogen atom, etc.) is introduced. According to the present invention, the problem of adhesion to the wall surface of the drying apparatus during drying and the problem of adhesion to the roll when various compounding agents are blended using a roll become more prominent. For example, even when a carboxyl group-containing acrylic rubber is used, these problems can be effectively solved.

The acrylic rubber of the present invention only needs to contain at least one lubricant selected from phosphoric acid esters, fatty acid esters, fatty acid amides, and higher fatty acids, and among these, selected from phosphoric acid esters and higher fatty acids. Those containing at least one lubricant are preferred.

Examples of the phosphoric acid ester include polyoxyethylene stearyl ether phosphoric acid, polyoxyethylene lauryl ether phosphoric acid, polyoxyethylene oleyl ether phosphoric acid, polyoxyethylene higher alcohol phosphoric acid such as polyoxyethylene tridecyl ether phosphoric acid, Among these, polyoxyethylene stearyl ether phosphoric acid is preferable. The higher fatty acid is a fatty acid having 12 to 20 carbon atoms, preferably a fatty acid having 13 to 19 carbon atoms. As the higher fatty acid, a mixture of a plurality of higher fatty acids having different carbon numbers can be used.

The content of the specific lubricant in the acrylic rubber of the present invention is preferably 0.1 to 0.4% by weight, more preferably 0.15 to 0.3% by weight, still more preferably 0.2 to 0.3% by weight. %. When the content of the specific lubricant is within the above range, the handling property at the time of drying and the roll processability can be more effectively enhanced while suppressing the occurrence of bleeding. Note that the content of the specific lubricant can be obtained by dissolving acrylic rubber in tetrahydrofuran and performing GPC measurement using tetrahydrofuran as a developing solvent. Specifically, from the chart obtained by the GPC measurement, the integrated value of the peak corresponding to the molecular weight of the specific lubricant is obtained, and this integrated value is compared with the integrated value of the peak of the acrylic rubber. By obtaining the weight ratio from the corresponding molecular weight, the content of the specific lubricant can be obtained.

Further, as described above, the acrylic rubber of the present invention contains a specific lubricant, but the content of the acrylic rubber component in the acrylic rubber of the present invention is preferably 95% by weight or more, more preferably. Is 97% by weight or more, more preferably 98% by weight or more. That is, the acrylic rubber of the present invention can be said to be an acrylic rubber composition containing 95% by weight or more (more preferably 97% by weight or more, more preferably 98% by weight or more) of an acrylic rubber component.

<Method for producing acrylic rubber>
The acrylic rubber of the present invention can be produced, for example, by the following production method. That is,
An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization of a monomer for forming an acrylic rubber; and
Lubricant addition step of containing a specific lubricant in the emulsion polymerization liquid before coagulation,
It can be produced by a method for producing acrylic rubber comprising a coagulating step of obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization liquid and coagulating it.
In addition, in the said manufacturing method, the monomer for forming an acrylic rubber is previously mixed with the emulsifier and water in the said emulsion polymerization process, and a monomer emulsion is obtained (emulsion liquid preparation process), and obtained. In the state of the obtained monomer emulsion, emulsion polymerization can be performed (emulsion polymerization step). In such an embodiment, a specific lubricant is added to the monomer emulsion. It can also be set as the structure which performs emulsion polymerization later.

<Emulsion polymerization process>
The emulsion polymerization step in the production method of the present invention is a step of obtaining an emulsion polymerization solution by emulsion polymerization of a monomer for forming an acrylic rubber.

As the emulsion polymerization method in the emulsion polymerization step, an ordinary method may be used, and an emulsifier, a polymerization initiator, a polymerization terminator and the like can be used according to a conventional method.

The emulsifier is not particularly limited. For example, polyoxyethylene alkyl ethers such as polyoxyethylene dodecyl ether, polyoxyethylene alkyl phenol ethers such as polyoxyethylene nonylphenyl ether, and polyoxyethylene alkyls such as polyoxyethylene stearate. Nonionic emulsifiers such as esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene polyoxypropylene copolymers; salts of fatty acids such as myristic acid, palmitic acid, oleic acid, linolenic acid, alkylbenzene sulfones such as sodium dodecylbenzene sulfonate Acid salts, higher alcohol sulfates such as sodium lauryl sulfate, higher phosphate esters such as sodium alkyl phosphate, Anionic emulsifiers such as Rusuruhokohaku salt; and the like; alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, cationic emulsifiers such as ammonium chloride. These emulsifiers can be used alone or in combination of two or more. Among these nonionic emulsifiers, polyoxyethylene polypropylene glycol, polyethylene glycol monostearate, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenol ether are preferable. As the nonionic emulsifier, those having a weight average molecular weight of less than 10,000 are preferable, those having a weight average molecular weight of 500 to 8000 are more preferable, and those having a weight average molecular weight of 600 to 5000 are more preferable. Among these anionic emulsifiers, higher phosphate ester salts and higher alcohol sulfate ester salts are preferred.

Among these emulsifiers, at least one of a nonionic emulsifier and an anionic emulsifier is preferable, an anionic emulsifier is more preferably included, and a nonionic emulsifier and an anionic emulsifier are more preferably used in combination. By using a combination of a nonionic emulsifier and an anionic emulsifier, it is used in a coagulation step described later while effectively suppressing the occurrence of dirt due to adhesion of a polymer to a polymerization apparatus (for example, a polymerization tank) during emulsion polymerization. It is possible to reduce the amount of coagulant used, and as a result, the amount of coagulant in the finally obtained acrylic rubber can be reduced, thereby improving the water resistance of the resulting rubber cross-linked product. it can.

Also, by using a combination of a nonionic emulsifier and an anionic emulsifier, the emulsifying action can be enhanced, so that the amount of the emulsifier itself can also be reduced, and as a result, in the acrylic rubber finally obtained The residual amount of the emulsifier contained in can be reduced, whereby the water resistance of the resulting acrylic rubber can be further increased.

In the production method of the present invention, the use amount of the emulsifier is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, based on the total amount of the emulsifier to be used with respect to 100 parts by weight of the monomer used for the polymerization. More preferably, it is 1 to 3 parts by weight. In the case of using a combination of a nonionic emulsifier and an anionic emulsifier, the amount of the nonionic emulsifier used is more than 0 parts by weight, preferably 0 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization. 0.1 to 3 parts by weight, more preferably 0.5 to 2 parts by weight, and even more preferably 0.7 to 1.7 parts by weight. The amount of the anionic emulsifier used is 100 parts by weight of the monomer used for the polymerization. On the other hand, it is more than 0 parts by weight, 4 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.5 to 2 parts by weight, still more preferably 0.35 to 0.75 parts by weight. In addition, when the nonionic emulsifier is used in combination with the anionic emulsifier, the weight ratio of the nonionic emulsifier / anionic emulsifier is preferably 1/99 to 99/1, and preferably 10/90 to 80/20. More preferred is 25/75 to 75/25, still more preferred is 50/50 to 75/25, and even more preferred is 65/35 to 75/25.

As polymerization initiators, azo compounds such as azobisisobutyronitrile; organic peroxides such as diisopropylbenzene hydroperoxide, cumene hydroperoxide, paramentane hydroperoxide, benzoyl peroxide; sodium persulfate, persulfate Inorganic peroxides such as potassium, hydrogen peroxide, and ammonium persulfate; can be used. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.001 to 1.0 part by weight with respect to 100 parts by weight of the monomer used for the polymerization.

Moreover, it is preferable to use the organic peroxide and the inorganic peroxide as the polymerization initiator as a redox polymerization initiator in combination with a reducing agent. Although it does not specifically limit as a reducing agent used in combination, The compound containing metal ions in a reduced state, such as ferrous sulfate, sodium hexamethylenediamine tetraacetate, cuprous naphthenate; ascorbic acid, sodium ascorbate Ascorbic acid (salt) such as potassium ascorbate; Erythorbic acid (salt) such as erythorbic acid, sodium erythorbate, potassium erythorbate; saccharides; Sulphinates such as sodium hydroxymethanesulfinate; Sodium hydrogen hydride, sodium aldehyde sodium hydrogen sulfite, potassium hydrogen sulfite; pyrosulfites such as sodium pyrosulfite, potassium pyrosulfite, sodium hydrogen bisulfite, potassium hydrogen bisulfite; sodium thiosulfate Thiosulfates such as potassium thiosulfate; phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite (salt); pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, Examples thereof include pyrophosphorous acid (salt) such as sodium hydrogen pyrophosphite and potassium hydrogen pyrophosphite; sodium formaldehyde sulfoxylate and the like. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent used is preferably 0.0003 to 0.5 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

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 preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

The amount of water used is preferably 80 to 500 parts by weight, more preferably 100 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 molecular weight adjusting agent, a particle size adjusting agent, a chelating agent, and an oxygen scavenger can be used as necessary.

The emulsion polymerization may be carried out by any of batch, semi-batch and continuous methods, but the semi-batch method is preferred. Specifically, in the reaction system containing the polymerization initiator and the reducing agent, the polymerization reaction is performed while continuously dropping the monomer used for the polymerization to the polymerization reaction system from the start of the polymerization reaction to an arbitrary time. In addition, for at least one of the monomers used for the polymerization, the polymerization initiator, and the reducing agent, it is preferable to perform the polymerization reaction while continuously dropping into the polymerization reaction system from the start of the polymerization reaction to any time, It is more preferable to perform the polymerization reaction while continuously dropping the monomer, polymerization initiator, and reducing agent used for the polymerization from the start of the polymerization reaction to an arbitrary time while continuously dropping into the polymerization reaction system. By carrying out the polymerization reaction while continuously dropping them, emulsion polymerization can be carried out stably, and thereby the polymerization reaction rate can be improved. The polymerization is usually performed in a temperature range of 0 to 70 ° C., preferably 5 to 50 ° C.

When the polymerization reaction is carried out while continuously dropping the monomer used for polymerization, the monomer used for polymerization is mixed with an emulsifier and water to obtain a monomer emulsion (preparation of emulsion). Step), it is preferable to continuously drop in the state of a monomer emulsion. The method for preparing the monomer emulsion is not particularly limited, and includes a method of stirring the total amount of monomers used for polymerization, the total amount of emulsifier, and water using a stirrer such as a homomixer or a disk turbine. Can be mentioned. The amount of water used in the monomer emulsion is preferably 10 to 70 parts by weight, more preferably 20 to 50 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

In addition, when the polymerization reaction is carried out while continuously dropping into the polymerization reaction system from the start of the polymerization reaction to an arbitrary time for all of the monomer, polymerization initiator, and reducing agent used for the polymerization, these are separate. Or at least the polymerization initiator and the reducing agent may be mixed in advance and, if necessary, dropped into the polymerization system from the same dropping device as an aqueous solution. May be. After completion of dropping, the reaction may be continued for an arbitrary time in order to further improve the polymerization reaction rate.

<Specific lubricant addition process>
The specific lubricant addition step of the production method of the present invention is a step of incorporating the specific lubricant into the emulsion polymerization liquid before coagulation.

The method for causing the emulsion polymerization liquid to contain the specific lubricant is not particularly limited, and any method may be used as long as the emulsion polymerization liquid before coagulation can be in a state containing the specific lubricant. . For example, a specific lubricant may be added to the emulsion polymerization solution after the emulsion polymerization, or a solution before the emulsion polymerization, specifically, a solution used for the emulsion polymerization (for example, a simple substance for forming an acrylic rubber). A monomer emulsion is obtained by mixing a monomer with an emulsifier and water), and a specific lubricant is added to the emulsion, and emulsion polymerization is carried out in the presence of the specific lubricant, whereby emulsion polymerization containing the specific lubricant is performed. A liquid may be obtained. Among these, it is preferable that the specific lubricant is added to the emulsion polymerization solution after the emulsion polymerization from the viewpoint that the effects of the present invention can be further enhanced. In addition, although it does not specifically limit as an addition form of a specific lubricant, When a specific lubricant is solid at normal temperature, you may add in a solid state or you may add in the melted state.

According to the production method of the present invention, the specific lubricant can be favorably dispersed in the emulsion polymerization liquid before coagulation by preliminarily containing the specific lubricant in the emulsion polymerization liquid before coagulation. Therefore, this allows the specific lubricant to be contained in a well-dispersed state in the acrylic rubber after coagulation. And as a result, the specific acrylic can be appropriately contained in the obtained acrylic rubber (preferably, it can be contained in a uniformly dispersed state). It can be made excellent in handling at the time of drying and roll processability. Even when the specific lubricant is contained in the emulsion polymerization liquid before coagulation, the added specific lubricant is not substantially removed in the subsequent coagulation, washing, drying, etc. The effect can be fully exhibited. On the other hand, when a specific lubricant is added after solidification, it becomes difficult to disperse the specific lubricant in the acrylic rubber, and therefore the specific lubricant cannot be included in the acrylic rubber (particularly, uniformly) As a result, it becomes impossible to obtain the effect of blending the specific lubricant, that is, the effect of improving the handling property during drying and the roll processability.

The amount of addition of the specific lubricant in the specific lubricant addition step is not particularly limited and may be an amount according to the amount to be contained in the obtained acrylic rubber, but it is 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. On the other hand, it is preferably 0.1 to 0.4 parts by weight, more preferably 0.15 to 0.3 parts by weight, and still more preferably 0.2 to 0.3 parts by weight.

In the production method of the present invention, in addition to the specific lubricant, some of the compounding agents to be blended with the acrylic rubber, specifically, anti-aging agents and / or ethylene oxide polymers are also coagulated. It is preferable to make it contain beforehand in the emulsion polymerization liquid before performing.

For example, by preliminarily containing an anti-aging agent in the emulsion polymerization liquid before coagulation, deterioration of the acrylic rubber due to heat during drying in the drying step described later can be effectively suppressed. Specifically, it is possible to effectively suppress a decrease in Mooney viscosity due to deterioration due to heating during drying, thereby effectively reducing the normal tensile strength and elongation at break when a rubber cross-linked product is obtained. It can be raised. In addition, in the state of the emulsion polymerization liquid before coagulation, by blending the anti-aging agent, the anti-aging agent can be appropriately dispersed, so even when the amount of the anti-aging agent is reduced, The effect of addition can be sufficiently exhibited. Specifically, the blending amount of the antioxidant is preferably 0.1 to 2 parts by weight, more preferably 0.2 to 1.2 parts by weight with respect to 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. Even when the amount is relatively small, the effect of the addition can be sufficiently exhibited. Even when the anti-aging agent is contained in the emulsion polymerization solution before coagulation, the added anti-aging agent is not substantially removed in the subsequent coagulation, washing, drying, etc. The effect of the addition can be sufficiently exhibited. Moreover, as a method of containing an anti-aging agent in an emulsion polymerization solution, a method of adding to an emulsion polymerization solution after emulsion polymerization and before coagulation, or a method of adding to a solution before emulsion polymerization is performed However, when added to a solution before emulsion polymerization, aggregates may be generated during emulsion polymerization, which may cause contamination of the polymerization apparatus. And the method of adding to the emulsion polymerization liquid before coagulating is more preferable.

The antiaging agent is not particularly limited, but 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylphenol, butylhydroxyanisole, 2,6-di-t-butyl- α-dimethylamino-p-cresol, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2,2′-methylene-bis (6-α-methyl- Benzyl-p-cresol), 4,4'-methylenebis (2,6-di-t-butylfunol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 3- (3 Butylation reaction of stearyl 5-di-tert-butyl-4-hydroxyphenyl) propionate, alkylated bisphenol, p-cresol and dicyclopentadiene Phenol-based antioxidants containing no sulfur atom, such as reaction products; 2,4-bis [(octylthio) methyl] -6-methylphenol, 2,2′-thiobis- (4-methyl-6-t-butylphenol) ), 4,4′-thiobis- (6-tert-butyl-o-cresol), 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine Thiophenol-based antioxidants such as 2-ylamino) phenol; phosphite-based antioxidants such as tris (nonylphenyl) phosphite, diphenylisodecyl phosphite, tetraphenyldipropylene glycol diphosphite; thiodipropionic acid Sulfur ester type antioxidants such as dilauryl; phenyl-α-naphthylamine, phenyl-β-naphthylamine, p- (p -Toluenesulfonylamido) -diphenylamine, 4,4 '-(α, α-dimethylbenzyl) diphenylamine, N, N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, butyraldehyde -Amine-based antioxidants such as aniline condensates; Imidazole-based antioxidants such as 2-mercaptobenzimidazole; Quinoline-based antioxidants such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline Hydroquinone anti-aging agents such as 2,5-di- (t-amyl) hydroquinone; and the like. These anti-aging agents may be used alone or in combination of two or more.

In addition, by preliminarily containing an ethylene oxide polymer in the emulsion polymerization solution before coagulation, the coagulation property of the emulsion polymerization solution can be improved, thereby reducing the amount of coagulant in the coagulation step. Therefore, the residual amount in the finally obtained acrylic rubber can be reduced, and the compression set resistance and water resistance in the case of a rubber cross-linked product can be improved. The ethylene oxide polymer is not particularly limited as long as it is a polymer having a polyethylene oxide structure as the main chain structure, and examples thereof include polyethylene oxide, polypropylene oxide, and ethylene oxide / propylene oxide copolymers. Polyethylene oxide is preferred. The blending amount of the ethylene oxide polymer is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.6 part by weight, still more preferably 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. 0.02 to 0.5 parts by weight. The weight average molecular weight of the ethylene oxide polymer is preferably 10,000 to 1,000,000, more preferably 10,000 to 200,000, and still more preferably 20,000 to 120,000. In addition, as a method of adding an ethylene oxide polymer to an emulsion polymerization solution, it is added to an emulsion polymerization solution after emulsion polymerization and before coagulation, or added to a solution before emulsion polymerization. A method is mentioned.

In addition, the addition order in the case of adding an anti-aging agent and / or an ethylene oxide polymer in addition to the specific lubricant to the emulsion polymerization solution before coagulation is not particularly limited, and may be appropriately selected. .

<Coagulation process>
The coagulation step in the production method of the present invention is a step of obtaining a hydrous crumb by adding a coagulant to the emulsion polymerization liquid obtained by the emulsion polymerization step.

The coagulant is not particularly limited, and examples thereof include monovalent to trivalent metal salts. The monovalent to trivalent metal salt is a salt containing a metal that becomes a monovalent to trivalent metal ion when dissolved in water, and is not particularly limited. For example, an inorganic acid selected from hydrochloric acid, nitric acid, sulfuric acid, and the like And a salt of an organic acid such as acetic acid or the like with a metal selected from sodium, potassium, lithium, magnesium, calcium, zinc, titanium, manganese, iron, cobalt, nickel, aluminum, tin and the like. Further, hydroxides of these metals can also be used.

Specific examples of monovalent to trivalent metal salts include sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, and chloride. Metal chlorides such as tin; nitrates such as sodium nitrate, potassium nitrate, lithium nitrate, magnesium nitrate, calcium nitrate, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate, tin nitrate; sodium sulfate And sulfates such as potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate and tin sulfate; Among these, calcium chloride, sodium chloride, aluminum sulfate, magnesium chloride, magnesium sulfate, zinc chloride, zinc sulfate, and sodium sulfate are preferable. Of these, monovalent or divalent metal salts are preferable, calcium chloride, sodium chloride, magnesium sulfate, and sodium sulfate are more preferable, and magnesium sulfate and sodium sulfate are more preferable. Moreover, these can be used individually by 1 type or in combination of multiple types.

The use amount of the coagulant can reduce the residual amount of the coagulant in the acrylic rubber finally obtained while making the coagulation of the acrylic rubber sufficient, and in this way, when the rubber cross-linked product is obtained, From the viewpoint of improving compression set resistance and water resistance, the amount is preferably 1 to 100 parts by weight, more preferably 2 to 40 parts by weight, and still more preferably 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. 3 to 20 parts by weight, particularly preferably 3 to 12 parts by weight.

The solidification temperature is not particularly limited, but is preferably 50 to 90 ° C, more preferably 60 to 90 ° C.

<Washing process>
In the manufacturing method of this invention, it is preferable to further provide the washing | cleaning process which wash | cleans with respect to the water-containing crumb obtained in the above-mentioned coagulation | solidification process.

The washing method is not particularly limited, and examples thereof include a method of washing with water by using water as a washing liquid and mixing the added water together with the hydrated crumb. The temperature at the time of washing with water is not particularly limited, but is preferably 5 to 60 ° C., more preferably 10 to 50 ° C., and the mixing time is 1 to 60 minutes, more preferably 2 to 30 minutes.

In addition, the amount of water to be added to the hydrated crumb at the time of washing with water is not particularly limited, but from the viewpoint that the residual amount of coagulant in the finally obtained acrylic rubber can be effectively reduced, The amount of water per washing is preferably 50 to 9,800 parts by weight, more preferably 300 to 1,800 parts per 100 parts by weight of the solid content (mainly acrylic rubber component) contained in the hydrous crumb. Parts by weight.

The number of times of washing with water is not particularly limited, and may be one, but is preferably 2 to 10 times, more preferably 3 to 8 from the viewpoint of reducing the residual amount of coagulant in the finally obtained acrylic rubber. Times. In addition, from the viewpoint of reducing the residual amount of coagulant in the finally obtained acrylic rubber, it is desirable that the number of times of washing with water is large. On the other hand, it is preferable that the number of washings is in the above range because the influence of the decrease in productivity is increased by increasing the number of steps.

In the present invention, after washing with water, acid washing using an acid as a washing solution may be performed. By performing the acid cleaning, the compression set resistance in the case of a rubber cross-linked product can be further improved. When the acrylic rubber is a carboxyl group-containing acrylic rubber having a carboxyl group, this acid cleaning The effect of improving the compression set resistance is particularly great. The acid used for the acid cleaning is not particularly limited, and sulfuric acid, hydrochloric acid, phosphoric acid and the like can be used without limitation. In addition, when acid is added to water-containing crumbs in acid washing, it is preferably added in the form of an aqueous solution, preferably pH = 6 or less, more preferably pH = 4 or less, and even more preferably pH = 3 or less. It is preferable to add in the state of aqueous solution. The acid washing method is not particularly limited, and examples thereof include a method of mixing an aqueous solution of the added acid together with water-containing crumb.

The temperature during the acid cleaning is not particularly limited, but is preferably 5 to 60 ° C., more preferably 10 to 50 ° C., and the mixing time is 1 to 60 minutes, more preferably 2 to 30 minutes. The pH of the washing water for the acid washing is not particularly limited, but is preferably pH = 6 or less, more preferably pH = 4 or less, and further preferably pH = 3 or less. The pH of the acid-washed wash water can be determined, for example, by measuring the pH of the water contained in the hydrous crumb after the acid wash.

After the acid cleaning, it is preferable to perform further water washing, and the water washing conditions may be the same as those described above.

<Drying process>
Moreover, in the manufacturing method of this invention, it is preferable to further provide the drying process which dries with respect to the water-containing crumb which wash | cleaned in the said washing | cleaning process.

Although it does not specifically limit as a drying method in a drying process, For example, it can be dried using dryers, such as a screw type extruder, a kneader type dryer, an expander dryer, a hot air dryer, and a vacuum dryer. . Moreover, you may use the drying method which combined these. Furthermore, before performing drying in the drying step, if necessary, the water-containing crumb may be filtered using a sieve such as a rotary screen or a vibrating screen; a centrifugal dehydrator;

For example, the drying temperature in the drying step is not particularly limited and varies depending on the dryer used for drying. For example, when a hot air dryer is used, the drying temperature is preferably 80 to 200 ° C., 100 More preferably, the temperature is set to ˜170 ° C.

According to the production method of the present invention, the acrylic rubber of the present invention can be obtained as described above.

The Mooney viscosity (ML1 + 4, 100 ° C.) (polymer Mooney) of the acrylic rubber of the present invention thus produced is preferably 10 to 80, more preferably 20 to 70, and further preferably 25 to 60.

In the acrylic rubber of the present invention, the residual amount of the coagulant contained in the acrylic rubber is preferably 10,000 ppm by weight or less, more preferably 7,000 ppm by weight or less, and still more preferably 5,000 by weight. ppm or less, particularly preferably 3,500 ppm or less. The lower limit of the residual amount of the coagulant is not particularly limited, but is preferably 10 ppm by weight or more. By setting the residual amount of the coagulant in the acrylic rubber within the above range, the compression set resistance and water resistance in the case of a rubber cross-linked product can be improved. In addition, the residual amount of a coagulant can be calculated | required by performing elemental analysis with respect to acrylic rubber, for example, and measuring content of the element contained in a coagulant. In addition, the method of setting the residual amount of the coagulant as described above is not particularly limited, and examples thereof include a method of setting the addition amount of the coagulant as described above, a method of adjusting the washing conditions as described above, and the like. It is done.

Furthermore, in the acrylic rubber of the present invention, the residual amount of the emulsifier contained in the acrylic rubber is preferably 22,000 ppm by weight or less, more preferably 20,000 ppm by weight or less, and even more preferably 18,000 ppm by weight. Hereinafter, it is particularly preferably 17,000 ppm by weight or less. Although the minimum of the residual amount of an emulsifier is not specifically limited, Preferably it is 10 weight ppm or more, More preferably, it is 200 weight ppm or more, More preferably, it is 500 weight ppm or more. By setting the residual amount of the emulsifier in the acrylic rubber within the above range, the water resistance in the case of a rubber cross-linked product can be further increased. In addition, the residual amount of an emulsifier can be calculated | required from the peak area of the molecular weight corresponding to an emulsifier in the measurement chart obtained by performing GPC measurement with respect to acrylic rubber, for example. Further, the method of setting the residual amount of the emulsifier as described above is not particularly limited. For example, as described above, a nonionic emulsifier and an anionic emulsifier are used in combination as the emulsifier, and the addition amount thereof is described above. The method of making it into the range which was carried out is mentioned.

<Acrylic rubber composition>
The acrylic rubber composition of the present invention is obtained by blending a crosslinking agent with the above-described acrylic rubber of the present invention.

Although it does not specifically limit as a crosslinking agent, For example, polyvalent amine compounds, such as a diamine compound, and its carbonate; Sulfur; Sulfur donor; Triazine thiol compound; Multivalent epoxy compound; Organic carboxylic acid ammonium salt; Conventionally known crosslinking agents such as oxides, dithiocarbamic acid metal salts, polyvalent carboxylic acids, quaternary onium salts, imidazole compounds, isocyanuric acid compounds, and organic peroxides can be used. These crosslinking agents can be used alone or in combination of two or more. The crosslinking agent is preferably selected as appropriate according to the type of the crosslinkable monomer unit.

Among these, when the acrylic rubber of the present invention has an α, β-ethylenically unsaturated carboxylic acid monomer unit as a crosslinkable monomer unit, a polyvalent amine compound as a crosslinking agent, and It is preferable to use the carbonate.

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-hexane diamine. 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 invention is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, and particularly preferably 0.1 parts by weight with respect to 100 parts by weight of the acrylic rubber. 2 to 4 parts by weight. By setting the content of the cross-linking agent in the above range, the mechanical strength as a rubber cross-linked product can be made excellent while the rubber elasticity is sufficient.

The acrylic rubber composition of the present invention preferably further contains a crosslinking accelerator. The crosslinking accelerator is not particularly limited, but when the acrylic rubber of the present invention has a carboxyl group as a crosslinkable group and the crosslinking agent is a polyvalent amine compound or a carbonate thereof. Guanidine compounds, diazabicycloalkene compounds, imidazole compounds, quaternary onium salts, tertiary phosphine compounds, aliphatic monovalent secondary amine compounds, aliphatic monovalent tertiary amine compounds, and the like can be used. Among these, guanidine compounds, diazabicycloalkene compounds, and aliphatic monovalent secondary amine compounds are preferable, and guanidine compounds are particularly preferable. These basic crosslinking accelerators can be used singly or in combination of two or more.

Specific examples of the guanidine compound include 1,3-di-o-tolylguanidine, 1,3-diphenylguanidine and the like. Specific examples of the diazabicycloalkene compound include 1,8-diazabicyclo [5.4.0] unde-7-cene, 1,5-diazabicyclo [4.3.0] no-5-ene and the like. . Specific examples of the imidazole compound include 2-methylimidazole and 2-phenylimidazole. Specific examples of the quaternary onium salt include tetra n-butylammonium bromide and octadecyltri n-butylammonium bromide. Specific examples of the tertiary phosphine compound include triphenylphosphine and tri-p-tolylphosphine.

An aliphatic monovalent secondary amine compound is a compound in which two hydrogen atoms of ammonia are substituted with an aliphatic hydrocarbon group. The aliphatic hydrocarbon group substituted for the hydrogen atom is preferably one having 1 to 30 carbon atoms. Specific examples of the aliphatic monovalent secondary amine compound include dimethylamine, diethylamine, dipropylamine, diallylamine, diisopropylamine, di-n-butylamine, di-t-butylamine, di-sec-butylamine, dihexylamine, di Examples include heptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine, ditetradecylamine, dipentadecylamine, dicetylamine, di-2-ethylhexylamine, and dioctadecylamine.

An aliphatic monovalent tertiary amine compound is a compound in which all three hydrogen atoms of ammonia are substituted with an aliphatic hydrocarbon group. The aliphatic hydrocarbon group substituted for the hydrogen atom is preferably one having 1 to 30 carbon atoms. Specific examples of the aliphatic monovalent tertiary amine compound include trimethylamine, triethylamine, tripropylamine, triallylamine, triisopropylamine, tri-n-butylamine, tri-t-butylamine, tri-sec-butylamine, trihexylamine. , Triheptylamine, trioctylamine, trinonylamine, tridecylamine, triundecylamine, and tridodecylamine.

The content of the crosslinking accelerator in the acrylic rubber composition of the present invention is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 7.5 parts by weight with respect to 100 parts by weight of the acrylic rubber. Parts, particularly preferably 1 to 5 parts by weight. By making content of a crosslinking accelerator into the said range, the tensile strength and compression set resistance of the rubber crosslinked material obtained can be improved more.

Moreover, the acrylic rubber composition of the present invention can contain a compounding agent usually used in the field of rubber processing, in addition to the above components. Examples of such compounding agents include reinforcing fillers such as silica and carbon black; non-reinforcing fillers such as calcium carbonate and clay; anti-aging agents; light stabilizers; scorch inhibitors; plasticizers; Adhesives; Adhesives; Lubricants; Lubricants; Flame retardants; Antifungal agents; Antistatic agents; Colorants; The compounding amount of these compounding agents is not particularly limited as long as it does not impair the object and effect of the present invention, and an amount corresponding to the compounding purpose can be appropriately compounded.

Furthermore, in the acrylic rubber composition of the present invention, rubbers, elastomers, resins and the like other than the acrylic rubber of the present invention described above may be further blended within a range not impairing the effects of the present invention. For example, rubber other than acrylic rubber such as acrylic rubber other than the acrylic rubber of the present invention, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicon rubber, fluorine rubber, etc .; Elastomers such as elastomers, styrene elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, polysiloxane elastomers; polyolefin resins, polystyrene resins, polyacrylic resins, polyphenylene ether resins, polyesters Resin, polycarbonate resin, polyamide resin, vinyl chloride resin, fluororesin, etc. can be blended. In addition, the total blending amount of the rubber, elastomer, and resin other than the acrylic rubber of the present invention described above is preferably 50 parts by weight or less, more preferably 10 parts by weight or less, further preferably 100 parts by weight of acrylic rubber. 1 part by weight or less.

In the acrylic rubber composition of the present invention, the acrylic rubber is blended with a crosslinking agent and other various compounding agents used as necessary, mixed and kneaded with a Banbury mixer or a kneader, and then using a kneading roll. Further, it is prepared by kneading.

The blending order of each component is not particularly limited, but after sufficiently mixing components that are difficult to react and decompose with heat, a crosslinking agent that is a component that easily reacts and decomposes with heat at a temperature at which reaction and decomposition do not occur. It is preferable to mix in a short time.

<Rubber cross-linked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the acrylic rubber composition of the present invention described above.
The rubber cross-linked product of the present invention uses the acrylic rubber composition of the present invention, is molded by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, and a roll, and is heated. It can be produced by carrying out a cross-linking reaction and fixing the shape as a rubber cross-linked product. In this case, crosslinking may be performed after molding in advance, or crosslinking may be performed simultaneously with molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 120 ° C. The crosslinking temperature is usually 130 to 220 ° C., preferably 150 to 190 ° C., and the crosslinking time is usually 2 minutes to 10 hours, preferably 3 minutes to 5 hours. As a heating method, a method used for crosslinking of rubber, such as press heating, steam heating, oven heating, and hot air heating, may be appropriately selected.

Further, depending on the shape and size of the rubber cross-linked product, the rubber cross-linked product of the present invention may be further heated to perform secondary crosslinking. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., but is preferably performed for 1 to 48 hours. What is necessary is just to select a heating method and heating temperature suitably.

The rubber cross-linked product of the present invention thus obtained can be used for sealing materials such as O-rings, packings, oil seals and bearing seals in a wide range of fields such as transport machines such as automobiles, general equipment, and electrical equipment. Gaskets; shock-absorbing materials; vibration-proofing materials; electric wire covering materials; industrial belts; tubes and hoses; sheets;

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The “parts” in each example are based on weight unless otherwise specified.
Various physical properties were evaluated according to the following methods.

[Mooney viscosity (ML1 + 4, 100 ° C.)]
The Mooney viscosity (polymer Mooney) of the acrylic rubber was measured according to JIS K6300.

[Content of specific lubricant in acrylic rubber]
The content of the specific lubricant in the acrylic rubber was measured by dissolving the acrylic rubber in tetrahydrofuran and performing GPC measurement using tetrahydrofuran as a developing solvent. Specifically, from the chart obtained by GPC measurement, find the integrated value of the peak corresponding to the molecular weight of the specific lubricant used in the production, compare these integrated values with the integrated value of the acrylic rubber peak, The content of the specific lubricant was calculated by determining the weight ratio from these integrated values and the corresponding molecular weight.

[Probe tack test]
The acrylic rubber composition was subjected to a probe tack test using a tacking tester (TAC-1000: manufactured by Reska). Specifically, with respect to an acrylic rubber sample molded to 30 mm × 20 mm × 2 mm, a SUS probe (10 mmφ) was pressed under the conditions of a pressing speed of 0.05 mm / s, a pressing load: 20 gf, and a pressing holding time of 10 seconds. A tacking operation (N) was measured when the SUS probe was pulled up at a lifting speed of 15 mm / s. It can be judged that the lower the tack strength, the lower the adhesiveness to the roll when processed with a roll, and the better the roll processability.

[Tensile strength, elongation]
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 was subjected to primary crosslinking by pressing at 170 ° C. for 20 minutes while being pressed at a press pressure of 10 MPa. The product was further subjected to secondary crosslinking by heating at 170 ° C. for 4 hours in a gear-type oven to obtain a sheet-like rubber crosslinked product. The obtained rubber cross-linked product was punched with a No. 3 type dumbbell to prepare a test piece. Next, using this test piece, tensile strength and elongation were measured according to JIS K6251.

[Bleed test]
About an acrylic rubber composition, the sheet-like rubber crosslinked material was obtained on the same conditions as the above. The obtained rubber cross-linked product was judged visually after being left at room temperature for 1 day. When bleed, white powder or liquid can be confirmed on the surface of the rubber cross-linked product.
Bleed may cause dirt when used as various materials, or may cause equipment failure due to the bleed substance. If bleed occurs, the usage may be limited. It is desirable not to. However, it can be used without any problem in applications where there is no problem even if bleeding occurs.

[Production Example 1]
In a mixing vessel equipped with a homomixer, 46.294 parts pure water, 49.3 parts ethyl acrylate, 49.3 parts n-butyl acrylate, 1.4 parts mono-n-butyl fumarate, anionic surfactant Sodium lauryl sulfate (trade name “Emar 2FG”, manufactured by Kao Corporation) 0.567 parts, polyoxyethylene dodecyl ether (trade name “Emalgen 105”, non-ionic surfactant), weight average molecular weight: about 1500, Kao 1.4 parts, and polyoxyethylene stearyl ether phosphoric acid (trade name “Phosphanol RL-210”, weight average molecular weight: about 500, manufactured by Toho Chemical Industry Co., Ltd.) 0.25 parts as a lubricant. By stirring, a monomer emulsion was obtained.

Subsequently, 1700.853 parts of pure water and 2.97 parts of the monomer emulsion obtained above were charged into a polymerization reaction tank equipped with a thermometer and a stirrer, and the temperature was 12 ° C. under a nitrogen stream. Until cooled. Then, in the polymerization reaction tank, 145.54 parts of the monomer emulsion obtained above, 0.00033 parts of ferrous sulfate as a reducing agent, 0.264 parts of sodium ascorbate as a reducing agent, and Then, 7.72 parts of a 2.85 wt% potassium persulfate aqueous solution (0.22 parts as the amount of potassium persulfate) as a polymerization initiator was continuously added dropwise over 3 hours. Thereafter, the reaction was continued for 1 hour while maintaining the temperature in the polymerization reaction vessel at 23 ° C., and it was confirmed that the polymerization conversion rate reached 95%, and polymerization was carried out by adding hydroquinone as a polymerization terminator. The reaction was stopped to obtain an emulsion polymerization solution.

Then, 100 parts of the emulsion polymerization solution obtained by polymerization is stearyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name “Irganox 1076”, BASF) as an anti-aging agent. Co., Ltd.) 0.3 parts (total of the monomers used in the production of the emulsion polymerization liquid (that is, ethyl acrylate, n-butyl acrylate, mono n-butyl fumarate) 100 parts 1 part) and 0.011 part of polyethylene oxide (weight average molecular weight (Mw) = 100,000) (0.039 with respect to a total of 100 parts of the monomers used for producing the emulsion polymerization liquid) Part) was mixed to obtain a mixed solution. Then, the obtained mixed liquid was transferred to a coagulation tank. To 100 parts of this mixed liquid, 60 parts of industrial water was added and the temperature was raised to 85 ° C., and then the mixed liquid was stirred at a temperature of 85 ° C. However, 3.3 parts of sodium sulfate as a coagulant (11 parts with respect to 100 parts of the polymer contained in the mixed solution) was continuously added to solidify the polymer, and then filtered to remove acrylic. A water-containing crumb of rubber (A1) was obtained.

Next, 388 parts of industrial water was added to 100 parts of the solid content of the hydrated crumb obtained above, and after stirring for 5 minutes at room temperature in the coagulation tank, the water content was discharged from the coagulation tank. The crumb was washed with water. In this production example, such washing with water was repeated four times.

Next, a sulfuric acid aqueous solution (pH = 3) obtained by mixing 388 parts of industrial water and 0.13 part of concentrated sulfuric acid is added to 100 parts of the solid content of the hydrated crumb which has been washed with water in the above, and in the coagulation tank. After stirring for 5 minutes at room temperature, the water-containing crumb was pickled by draining water from the coagulation tank. The pH of the hydrated crumb after pickling (pH of water in the hydrated crumb) was measured, and the pH was 3. Next, 388 parts of pure water is added to 100 parts of solid content of the water-containing crumb subjected to pickling, and after stirring for 5 minutes at room temperature in the coagulation tank, the water is discharged from the coagulation tank, so that the water-containing crumb is discharged. The hydrated crumb that had been washed with pure water was dried at 110 ° C. for 1 hour with a hot air dryer (belt conveyor type band dryer) to obtain a solid acrylic rubber (A1). . At this time, adhesion of acrylic rubber to the hot air dryer was not observed.

The resulting acrylic rubber (A1) had a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A1) was 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Moreover, about acrylic rubber (A1), content of the lubricant in acrylic rubber (A1) was measured according to the said method. The results are shown in Table 1.

[Production Example 2]
As the lubricant, instead of 0.25 part of polyoxyethylene stearyl ether phosphoric acid, 0.25 part of higher fatty acid (trade name “Moldwiz Int21G”, manufactured by Sakai Kogyo Co., Ltd.) was used in the same manner as in Production Example 1. A monomer emulsion was obtained. Then, except that the obtained monomer emulsion was used, emulsion polymerization and coagulation were carried out in the same manner as in Production Example 1 to obtain a hydrous crumb of acrylic rubber (A2), and the resulting acrylic The rubber-containing crumb of rubber (A2) is solid acrylic by performing four times of water washing, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1. A rubber (A2) was obtained. At this time, adhesion of acrylic rubber to the hot air dryer during drying by the hot air dryer was not observed.

The resulting acrylic rubber (A2) had a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A2) was 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Moreover, about acrylic rubber (A2), content of the lubricant in acrylic rubber (A2) was measured according to the said method. The results are shown in Table 1.

[Production Example 3]
A monomer emulsion was obtained in the same manner as in Production Example 1 except that 0.25 part of polyoxyethylene stearyl ether phosphoric acid as a lubricant was not blended.

Subsequently, 1700.853 parts of pure water and 2.97 parts of the monomer emulsion obtained above were charged into a polymerization reaction tank equipped with a thermometer and a stirrer, and the temperature was 12 ° C. under a nitrogen stream. Until cooled. Next, in the polymerization reaction tank, 145.29 parts of the monomer emulsion obtained above, 0.00033 parts of ferrous sulfate as a reducing agent, 0.264 parts of sodium ascorbate as a reducing agent, polymerization 7.72 parts of an aqueous 2.85% by weight potassium persulfate solution as an initiator (0.22 parts as the amount of potassium persulfate) was continuously added dropwise over 3 hours. Thereafter, the reaction was continued for 1 hour while maintaining the temperature in the polymerization reaction vessel at 23 ° C., and it was confirmed that the polymerization conversion rate reached 95%, and polymerization was carried out by adding hydroquinone as a polymerization terminator. The reaction was stopped to obtain an emulsion polymerization solution.

Then, 100 parts of the emulsion polymerization solution obtained by polymerization is stearyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name “Irganox 1076”, BASF) as an anti-aging agent. Co., Ltd.) 0.3 parts (total of the monomers used in the production of the emulsion polymerization liquid (that is, ethyl acrylate, n-butyl acrylate, mono n-butyl fumarate) 100 parts 1 part), 0.011 part of polyethylene oxide (weight average molecular weight (Mw) = 100,000) (0.039 part with respect to a total of 100 parts of the charged monomers used in producing the emulsion polymerization liquid) ), And polyoxyethylene stearyl ether phosphoric acid (trade name “phosphanol RL-210”, weight average molecular weight: about 500, Toho Chemical Industries, Ltd.) ) Was obtained 0.075 parts (mixture by mixing 0.25 parts per 100 parts of monomer charged) was used in preparing the polymer emulsion. Then, the obtained mixed liquid was transferred to a coagulation tank. To 100 parts of this mixed liquid, 60 parts of industrial water was added and the temperature was raised to 85 ° C., and then the mixed liquid was stirred at a temperature of 85 ° C. However, 3.3 parts of sodium sulfate as a coagulant (11 parts with respect to 100 parts of the polymer contained in the mixed solution) was continuously added to coagulate the polymer, whereby acrylic rubber (A3) Of hydrated crumbs.

Next, the water-containing crumb of the obtained acrylic rubber (A3) is subjected to water washing, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1. Thus, a solid acrylic rubber (A3) was obtained. At this time, adhesion of acrylic rubber to the hot air dryer during drying by the hot air dryer was not observed.

The resulting acrylic rubber (A3) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A3) has a composition of 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Further, the content of the lubricant in the acrylic rubber (A3) was measured according to the above method. The results are shown in Table 1.

[Production Example 4]
As a lubricant to be blended with respect to 100 parts by weight of the emulsion polymerization solution obtained in the same manner as in Production Example 3, instead of 0.075 part of polyoxyethylene stearyl ether phosphoric acid, a higher fatty acid (trade name “Moldwiz Int21G”, 巴Except for using 0.075 part (manufactured by Kogyo Co., Ltd.) (0.25 part with respect to a total of 100 parts of the charged monomers used in producing the emulsion polymerization liquid), in the same manner as in Production Example 3, A mixed liquid was prepared, and a water-containing crumb of acrylic rubber (A4) was obtained by performing a coagulation operation.

Next, the water-containing crumb of the obtained acrylic rubber (A4) is subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1. Thus, a solid acrylic rubber (A4) was obtained. At this time, adhesion of acrylic rubber to the hot air dryer during drying by the hot air dryer was not observed.

The resulting acrylic rubber (A4) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A4) has a composition of 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Further, the content of the lubricant in the acrylic rubber (A4) was measured according to the above method. The results are shown in Table 1.

[Production Example 5]
A monomer emulsion was obtained in the same manner as in Production Example 1 except that the blending amount of polyoxyethylene stearyl ether phosphoric acid as a lubricant was changed from 0.25 parts to 0.5 parts. Then, except that the obtained monomer emulsion was used, emulsion polymerization and coagulation were carried out in the same manner as in Production Example 1 to obtain a hydrous crumb of acrylic rubber (A5), and the resulting acrylic About the water-containing crumb of rubber (A5), in the same manner as in Production Example 1, solid acryl is obtained by performing four times of water washing, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer). A rubber (A5) was obtained. At this time, adhesion of acrylic rubber to the hot air dryer during drying by the hot air dryer was not observed.

The resulting acrylic rubber (A5) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A5) has a composition of 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Moreover, about acrylic rubber (A5), content of the lubricant in acrylic rubber (A5) was measured according to the said method. The results are shown in Table 1.

[Production Example 6]
A monomer emulsion was obtained in the same manner as in Production Example 2 except that the amount of the higher fatty acid as the lubricant was changed from 0.25 parts to 0.5 parts. Then, except that the obtained monomer emulsion was used, emulsion polymerization and coagulation were carried out in the same manner as in Production Example 2 to obtain a hydrated crumb of acrylic rubber (A6), and the resulting acrylic As for the water-containing crumb of rubber (A6), in the same manner as in Production Example 2, solid acryl is obtained by washing with water four times, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer). A rubber (A6) was obtained. At this time, adhesion of acrylic rubber to the hot air dryer during drying by the hot air dryer was not observed.

The resulting acrylic rubber (A6) had a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A6) had a composition of 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Moreover, about acrylic rubber (A6), content of the lubricant in acrylic rubber (A6) was measured according to the said method. The results are shown in Table 1.

[Production Example 7]
A mixed solution was prepared and coagulated in the same manner as in Production Example 3 except that polyoxyethylene stearyl ether phosphoric acid as a lubricant was not blended into the emulsion polymerization solution obtained in the same manner as in Production Example 3. By performing the operation, a water-containing crumb of acrylic rubber (A7) was obtained.

Next, the water-containing crumb of the obtained acrylic rubber (A7) is subjected to water washing, pickling, pure water washing and drying with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1. Thus, a solid acrylic rubber (A7) was obtained. In Production Example 7, adhesion of acrylic rubber to the hot air dryer was observed in the drying with the hot air dryer, and the operability was poor.

The resulting acrylic rubber (A7) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A7) has a composition of 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono-n-butyl fumarate units of 1.4% by weight. Further, the content of the lubricant in the acrylic rubber (A7) was measured according to the above method. The results are shown in Table 1.

[Example 1]
Using the acrylic rubber (A1) Banbury mixer obtained in Production Example 1, 100 parts of the acrylic rubber (A1) obtained in Production Example 1 was added to FEF carbon black (trade name “SEAST SO”, manufactured by Tokai Carbon Co., Ltd.) 60 parts, 2 parts of stearic acid, and 2 parts of 4,4′-bis (α, α-dimethylbenzyl) diphenylamine (trade name “NOCRACK CD”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) were added at 50 ° C. Mix for 5 minutes. Subsequently, the obtained mixture was transferred to a roll at 50 ° C., and 0.6 parts of hexamethylenediamine carbamate (trade name “Diak # 1”, manufactured by DuPont Dow Elastomer Co., Ltd., aliphatic polyvalent amine compound) and 1,3 -2 parts of di-o-tolylguanidine (trade name “Noxeller DT”, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., crosslinking accelerator) was blended and kneaded to obtain an acrylic rubber composition.

Then, using the obtained acrylic rubber composition, the probe tack test, the bleed test, the tensile strength, and the elongation were measured and evaluated according to the above method. The results are shown in Table 2.

[Examples 2 to 6, Comparative Example 1]
An acrylic resin was prepared in the same manner as in Example 1 except that the acrylic rubbers (A2) to (A7) obtained in Production Examples 2 to 7 were used in place of the acrylic rubber (A1) obtained in Production Example 1. Table 2 shows the results of measurement and evaluation in the same manner after obtaining the rubber composition.

[Comparative Example 2]
Comparative Example 1 except that 0.3 part of polyoxyethylene stearyl ether phosphate (trade name “Phosphanol RL-210”, weight average molecular weight: about 500, manufactured by Toho Chemical Industry Co., Ltd.) as a lubricant was further blended. Similarly, an acrylic rubber composition was obtained, and the results of measurement and evaluation in the same manner are shown in Table 2.

[Comparative Example 3]
An acrylic rubber composition was obtained in the same manner as in Comparative Example 1 except that 0.3 part of higher fatty acid (trade name “Moldwiz Int21G”, manufactured by Sakai Kogyo Co., Ltd.) as a lubricant was further blended, and similarly measured and evaluated. Table 2 shows the results obtained.

(* 1) The addition amount of the compounding agent for preparing the monomer emulsion is shown by the compounding amount with respect to 100 parts of the charged monomer.
(* 2) The addition amount of the compounding agent added to the emulsion polymerization solution before coagulation was shown as the compounding amount with respect to 100 parts of the emulsion polymerization solution.
(* 3) The addition amount of the coagulant used in the coagulation step is shown as a blending amount with respect to 100 parts of the liquid mixture obtained by adding an antioxidant, polyethylene oxide and / or lubricant to the emulsion polymerization liquid. .

As shown in Tables 1 and 2, the acrylic rubbers obtained in Production Examples 1 to 6 each contain a phosphate ester or higher fatty acid, which is a predetermined lubricant (specific lubricant) of the present invention. Acrylic rubber containing an appropriate lubricant does not cause adhesion of the acrylic rubber to the hot air dryer in the drying process, and is excellent in handling at the time of drying, and is obtained using such an acrylic rubber. The acrylic rubber composition had low tack strength in the probe tack test and excellent roll processability (Production Examples 1 to 6, Examples 1 to 6).
On the other hand, the acrylic rubber obtained by Production Example 7 does not contain the lubricant specified in the invention (specific lubricant), and in the drying process, adhesion of the acrylic rubber to the hot air dryer occurs, and at the time of drying The acrylic rubber composition obtained by using such an acrylic rubber is inferior in operability, and has a high tack strength in the probe tack test and is inferior in roll processability. When the acrylic rubber composition was prepared, the same was true when the predetermined lubricant (specific lubricant) of the present invention was blended (Comparative Examples 1 to 3).

Claims (18)

1. An acrylic rubber containing at least one lubricant selected from phosphoric acid esters, fatty acid esters, fatty acid amides, and higher fatty acids.
2. The acrylic rubber according to claim 1, wherein the lubricant contains at least one selected from a phosphate ester and a higher fatty acid.
3. The acrylic rubber according to claim 1 or 2, which contains polyoxyethylene higher alcohol phosphoric acid as the lubricant.
4. 3. The acrylic rubber according to claim 1 or 2, wherein the lubricant contains a fatty acid having 12 to 20 carbon atoms.
5. The acrylic rubber according to any one of claims 1 to 4, wherein the content of the lubricant is 0.1 to 0.4% by weight.
6. The acrylic rubber according to claim 5, wherein the content of the lubricant is 0.2 to 0.3% by weight.
7. The acrylic rubber according to any one of claims 1 to 6, wherein the content of the acrylic rubber component is 95% by weight or more.
8. The acrylic rubber according to any one of claims 1 to 7, wherein the acrylic rubber is an acrylic rubber containing a carboxyl group.
9. An acrylic rubber composition comprising the acrylic rubber according to any one of claims 1 to 8 and a crosslinking agent.
10. A crosslinked rubber product obtained by crosslinking the acrylic rubber composition according to claim 9.
11. A method for producing the acrylic rubber according to any one of claims 1 to 8,
    An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization of the monomer for forming the acrylic rubber; and
    A lubricant addition step of adding the lubricant to the emulsion polymerization solution before coagulation;
    A method for producing acrylic rubber, comprising: a coagulation step of obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization liquid and coagulating it.
12. A method for producing the acrylic rubber according to any one of claims 1 to 8,
    An emulsion preparation step for obtaining a monomer emulsion by mixing the monomer for forming the acrylic rubber with an emulsifier and water;
    A lubricant addition step of adding a lubricant to the monomer emulsion prepared in the emulsion preparation step;
    An emulsion polymerization step of obtaining an emulsion polymerization solution by emulsion polymerization of a monomer contained in the monomer emulsion added with a lubricant in the lubricant addition step;
    A method for producing acrylic rubber, comprising: a coagulation step of obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization liquid and coagulating it.
13. The amount of the lubricant added in the lubricant addition step is 0.1 to 0.4 parts by weight with respect to 100 parts by weight of the acrylic rubber component contained in the emulsion polymerization liquid. A method for producing acrylic rubber.
14. The acrylic rubber according to claim 13, wherein an amount of the lubricant added in the lubricant adding step is 0.2 to 0.3 parts by weight with respect to 100 parts by weight of the acrylic rubber component contained in the emulsion polymerization liquid. Manufacturing method.
15. The method for producing acrylic rubber according to any one of claims 10 to 14, wherein the emulsion polymerization of the monomer in the emulsion polymerization step is performed in the presence of a nonionic emulsifier and an anionic emulsifier.
16. The method for producing an acrylic rubber according to claim 15, wherein the amount of the nonionic emulsifier and the anionic emulsifier used is 50/50 to 75/25 in a weight ratio of nonionic emulsifier / anionic emulsifier.
17. In the emulsion polymerization step, the emulsion polymerization reaction is performed while continuously dropping the monomer, the polymerization initiator, and the reducing agent for forming the acrylic rubber into the polymerization reaction system from the start of the polymerization reaction to an arbitrary time. The method for producing an acrylic rubber according to any one of claims 11 to 16.
18. While the monomer for forming the acrylic rubber is continuously added dropwise to the polymerization reaction system from the start of the polymerization reaction to an arbitrary time in the state of a monomer emulsion mixed with an emulsifier and water. The method for producing an acrylic rubber according to claim 17, wherein an emulsion polymerization reaction is performed.