JP6696584B2 - Acrylic rubber and method for producing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an acrylic rubber and a method for producing the same, and more particularly, 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 containing acrylic acid ester as a main component and is generally known as a rubber having excellent 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-polymerizing a monomer mixture constituting the acrylic rubber, adding a coagulant to the obtained emulsion-polymerized solution to coagulate, and drying the hydrous crumb obtained by coagulation. It is manufactured by doing (see, for example, Patent Document 1). A hot air drier is usually used for drying the water-containing crumb, 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 such drying of the 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, which lowers the operability. Furthermore, the conventional acrylic rubber such as the acrylic rubber described in Patent Document 1 easily sticks to the roll when various compounding agents are blended by using the roll, and the workability in processing with the roll is high. There was also a problem that it was not enough.

JP-A-7-145291

  The present invention has been made in view of such circumstances, and an object of the present invention 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 earnest studies for achieving the above object, the present inventors have found that the above object can be achieved by containing a specific lubricant in acrylic rubber, and have completed the present invention.

That is, according to the present invention, there is provided an acrylic rubber containing at least one lubricant selected from phosphoric acid ester, fatty acid ester, fatty acid amide, and higher fatty acid.
The lubricant preferably contains at least one selected from phosphoric acid esters and higher fatty acids, and more preferably contains polyoxyethylene higher alcohol phosphoric acid or fatty acids having 12 to 20 carbon atoms.
The content of the lubricant is preferably 0.1 to 0.4% by weight, more preferably 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 above-mentioned acrylic rubber and a cross-linking agent, and a rubber cross-linked product obtained by cross-linking such an acrylic rubber composition.

Further, according to the present invention, there is provided a method for producing the acrylic rubber, which comprises emulsion-polymerizing a monomer for forming the acrylic rubber to obtain an emulsion-polymerized solution, and performing coagulation. A method for producing an acrylic rubber, comprising: a step of adding a lubricant to the emulsion polymerization solution before the step of adding a lubricant; and a step of adding a coagulant to the emulsion polymerization solution and coagulating to obtain a hydrous crumb. Will be provided.
Alternatively, according to the present invention, there is provided a method for producing the acrylic rubber, wherein a monomer for forming the acrylic rubber is mixed with an emulsifier and water to obtain a monomer emulsion. Preparation step, a lubricant addition step of adding a lubricant to the monomer emulsion prepared in the emulsion preparation step, and emulsifying the monomer contained in the monomer emulsion added with a lubricant in the lubricant addition step Provided is a method for producing an acrylic rubber, which comprises an emulsion polymerization step of polymerizing to obtain an emulsion polymerization solution, and a coagulation step of adding a coagulant to the emulsion polymerization solution to coagulate it to obtain a hydrous crumb. It

In the production method of the present invention, 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. It is preferably 0.2 to 0.3 parts by weight, and more preferably 0.2 to 0.3 parts by weight.
In the production method of the present invention, it is preferable that the emulsion polymerization of the monomer in the emulsion polymerization step is performed in the presence of a nonionic emulsifier and an anionic emulsifier.
In the production method of the present invention, the amount of the nonionic emulsifier and the anionic emulsifier used is preferably 50/50 to 75/25 in terms of the weight ratio of nonionic emulsifier / anionic emulsifier.
In the production method of the present invention, in the emulsion polymerization step, a monomer for forming the acrylic rubber, a polymerization initiator and a reducing agent are continuously added to the polymerization reaction system from the initiation of the polymerization reaction to an arbitrary time. It is preferable to carry out the emulsion polymerization reaction while dropping.
Further, in the production method of the present invention, the monomer for forming the acrylic rubber, in the state of a monomer emulsion prepared by mixing with an emulsifier and water, from the initiation of the polymerization reaction to any time, It is preferable to carry out the emulsion polymerization reaction while being continuously added dropwise to 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 comprises a (meth) acrylic acid ester monomer [acrylic acid as a main component (in the present invention, one having 50% by weight or more in all rubber monomer units) in the molecule. Means ester monomer and / or methacrylic acid ester monomer. Hereinafter, the same applies to methyl (meth) acrylate and the like. ] A rubbery polymer containing units, containing at least one lubricant selected from phosphoric acid ester, fatty acid ester, fatty acid amide, and higher fatty acid.

  The (meth) acrylic acid ester monomer forming the (meth) acrylic acid ester monomer unit, which is the main component of the acrylic rubber of the present invention, is not particularly limited, but for example, a (meth) acrylic acid alkyl ester monomer Examples thereof include a monomer and a (meth) acrylic acid alkoxyalkyl ester monomer.

  The (meth) acrylic acid alkyl ester monomer is not particularly limited, but an ester of an alkanol having 1 to 8 carbon atoms and (meth) acrylic acid is preferable, and specifically, (meth) acrylic acid methyl, ( Ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate and the like can be mentioned. Among these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and ethyl acrylate and n-butyl acrylate are particularly preferable. These may 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, and 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, and 4-methoxybutyl (meth) acrylate. Among these, 2-ethoxyethyl (meth) acrylate and 2-methoxyethyl (meth) acrylate are preferable, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferable. These may 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. It is 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 obtained rubber cross-linked product may decrease, while if it is too large, the rubber cross-linking obtained. The heat resistance of the product may decrease.

  In the acrylic rubber of the present invention, as the (meth) acrylic acid ester monomer unit, 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 a body unit consisting of 70 to 0% by weight.

  The acrylic rubber of the present invention may contain a crosslinkable monomer unit, if necessary, in addition to the (meth) acrylic acid alkyl ester monomer unit. The crosslinkable monomer forming the crosslinkable monomer unit is not particularly limited, but is, for example, an α, β-ethylenically unsaturated carboxylic acid monomer; a monomer having an epoxy group; a halogen atom. Monomers; diene monomers; and the like.

  The α, β-ethylenically unsaturated carboxylic acid monomer forming the α, β-ethylenically unsaturated carboxylic acid monomer unit is not particularly limited, but for example, 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 with. By using the α, β-ethylenically unsaturated carboxylic acid monomer, the acrylic rubber can be made into a carboxyl group-containing acrylic rubber having a carboxyl group as a cross-linking point. 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 butenedioic acid such as fumaric acid and maleic acid; itaconic acid; citraconic acid; chloromaleic acid.
Specific examples of monoesters of α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and alkanol having 1 to 8 carbon atoms include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, and malein. Butenedioic acid mono-chain alkyl ester such as monomethyl acid acid, monoethyl maleate, mono-n-butyl maleate; monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, malein Butenedioic acid monoester having an alicyclic structure such as acid monocyclohexenyl; itaconic acid monoester such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate, monocyclohexyl itaconate; and the like.
Among these, monoesters of α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and alkanol having 1 to 8 carbon atoms are preferable, butenedionic acid mono-chain alkyl ester or butenedione having an alicyclic structure. Acid monoesters are more preferable, mono-n-butyl fumarate, mono-n-butyl maleate, monocyclohexyl fumarate, and monocyclohexyl maleate are more preferable, and mono-n-butyl fumarate is particularly preferable. These α, β-ethylenically unsaturated carboxylic acid monomers may be used alone or in combination of two or more. Incidentally, among the above-mentioned monomers, the dicarboxylic acid includes those existing as an anhydride.

  The monomer having an epoxy group is not particularly limited, and examples thereof include epoxy group-containing (meth) acrylic acid ester such as glycidyl (meth) acrylate; epoxy group-containing ether such as allyl glycidyl ether and vinyl glycidyl ether; Is mentioned.

  The monomer having a halogen atom is not particularly limited, and examples thereof include unsaturated alcohol esters of halogen-containing saturated carboxylic acid, (meth) acrylic acid haloalkyl ester, (meth) acrylic acid haloacyloxyalkyl ester, (meth) acrylic acid. Examples thereof include acid (haloacetylcarbamoyloxy) alkyl ester, halogen-containing unsaturated ether, halogen-containing unsaturated ketone, halomethyl group-containing aromatic vinyl compound, halogen-containing unsaturated amide, and haloacetyl group-containing unsaturated monomer.

Specific examples of unsaturated alcohol esters of halogen-containing saturated carboxylic acids include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate.
Specific examples of the (meth) acrylic acid haloalkyl ester include chloromethyl (meth) acrylate, 1-chloroethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, and 1,2-dichloroethyl (meth) acrylate. , 2-chloropropyl (meth) acrylate, 3-chloropropyl (meth) acrylate, and 2,3-dichloropropyl (meth) acrylate.
Specific examples of the (meth) acrylic acid haloacyloxyalkyl ester 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 ester 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, p-chloromethyl-α-methylstyrene and the like.

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 chloroacetic acid ester.

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

  Among the above-mentioned crosslinkable monomers, when an α, β-ethylenically unsaturated carboxylic acid monomer is used, the acrylic rubber can be a carboxyl group-containing acrylic rubber. It is preferable to use a carboxyl group-containing acrylic rubber as the acrylic rubber, because it is possible to improve the compression set resistance while improving the oil resistance and heat resistance. Moreover, as will be described later, when the acrylic rubber is a carboxyl group-containing acrylic rubber, compared with the case where a crosslinkable group other than the carboxyl group (for example, an epoxy group, a halogen atom) is introduced, From this viewpoint, the carboxyl group-containing acrylic rubber is preferable because the action and effect can be made more remarkable.

  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. Is. By setting the content of the crosslinkable monomer unit in the above range, it is possible to more appropriately enhance the compression set resistance while improving the mechanical properties and heat resistance of the obtained rubber crosslinked product.

  The acrylic rubber of the present invention has, in addition to the (meth) acrylic acid ester monomer unit and the crosslinkable monomer unit optionally used, a unit of another monomer copolymerizable therewith. You may have. 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 the aromatic vinyl monomer include styrene, α-methylstyrene, divinylbenzene and the like.

Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.
Examples of the acrylamide-based monomer 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.

  The other copolymerizable monomer may be used alone 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.

  Further, the acrylic rubber of the present invention contains at least one lubricant selected from a phosphoric acid ester, a fatty acid ester, a fatty acid amide, and a higher fatty acid (hereinafter, appropriately referred to as “specific lubricant”), This makes it possible to appropriately reduce the tackiness, and as a result, it is possible to provide excellent handleability during drying and roll processability. Specifically, according to the acrylic rubber of the present invention, it is possible to effectively suppress the problem that the acrylic rubber is softened by the temperature during drying and adheres to the wall surface of the drying device, etc. The effect of being able to effectively suppress the decrease in operability due to the adhesion of rubber to the wall surface of the drying device, and also effectively suppressing the sticking to the roll when various compounding agents are blended using the roll. Therefore, it is possible to improve the workability when the roll is used for processing. In particular, when the acrylic rubber is a carboxyl group-containing acrylic rubber, by introducing a carboxyl group, the compression set resistance can be appropriately increased, while the action of the carboxyalkyl group results in high adhesiveness. It will be. When a carboxyl group-containing acrylic rubber is used as the acrylic rubber, the adhesiveness is high, and therefore, compared with the case where a crosslinkable group other than the carboxyl group (for example, epoxy group, halogen atom, etc.) is introduced. According to the present invention, the problem of adhesion to the wall surface of the drying device at the time of drying, and the problem of sticking to the roll when various compounding agents are mixed using the 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 may contain at least one lubricant selected from phosphoric acid ester, fatty acid ester, fatty acid amide, and higher fatty acid. Among these, selected from phosphoric acid ester and higher fatty acid. 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, and 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 during drying and the roll processability can be more effectively enhanced while suppressing the occurrence of bleeding. The content of the specific lubricant can be determined by dissolving acrylic rubber in tetrahydrofuran and performing GPC measurement using tetrahydrofuran as a developing solvent. Specifically, the integrated value of the peak corresponding to the molecular weight of the specific lubricant is obtained from the chart obtained by GPC measurement, and this integrated value is compared with the integrated value of the peak of acrylic rubber, and these integrated values are calculated. By determining the weight ratio from the corresponding molecular weight, the content of the specific lubricant can be determined.

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

<Method for producing acrylic rubber>
The acrylic rubber of the present invention can be manufactured, for example, by the following manufacturing method. That is,
By emulsion polymerization of a monomer for forming an acrylic rubber, an emulsion polymerization step of obtaining an emulsion polymerization liquid,
In the emulsion polymerization liquid before performing coagulation, a lubricant addition step of containing a specific lubricant,
It can be produced by a method for producing an acrylic rubber, which comprises a coagulation step of obtaining a hydrous crumb by adding a coagulant to an emulsion polymerization liquid and coagulating it.
In the above production method, the emulsion polymerization step is carried out by premixing a monomer for forming an acrylic rubber with an emulsifier and water to obtain a monomer emulsion (emulsion preparation step). In the state of the obtained monomer emulsion, it is also possible to adopt an embodiment in which emulsion polymerization is carried out (emulsion polymerization step). In such an embodiment, a specific lubricant was added to the monomer emulsion. It is also possible to adopt a configuration in which emulsion polymerization is performed later.

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

  As the emulsion polymerization method in the emulsion polymerization step, a usual 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, and examples thereof include polyoxyethylene alkyl ether such as polyoxyethylene dodecyl ether, polyoxyethylene alkylphenol ether such as polyoxyethylene nonylphenyl ether, and polyoxyethylene alkyl ester such as polyoxyethylene stearic acid ester. Nonionic emulsifiers such as esters, polyoxyethylene sorbitan alkyl esters and polyoxyethylene polyoxypropylene copolymers; salts of fatty acids such as myristic acid, palmitic acid, oleic acid and linolenic acid; alkylbenzene sulfone such as sodium dodecylbenzenesulfonate. Acid salts, higher alcohol sulfate salts such as sodium lauryl sulfate, higher phosphate salts such as sodium alkyl phosphate, anionic emulsifiers such as alkyl sulfosuccinates; alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride, etc. And a cationic emulsifier; These emulsifiers can be used alone or in combination of two or more kinds. Among these nonionic emulsifiers, polyoxyethylene polypropylene glycol, polyethylene glycol monostearate, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenol ether are preferable. The nonionic emulsifier preferably has a weight average molecular weight of less than 10,000, more preferably has a weight average molecular weight of 500 to 8,000, and further preferably has a weight average molecular weight of 600 to 5,000. Among these anionic emulsifiers, higher phosphate ester salts and higher alcohol sulfate ester salts are preferable.

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

  Further, 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 used can be reduced, and as a result, the acrylic rubber finally obtained The residual amount of the emulsifier contained in can be reduced, and thus the water resistance of the resulting acrylic rubber can be further enhanced.

  The amount of the emulsifier used in the production method of the present invention is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, based on 100 parts by weight of the monomer used for the polymerization. , And more preferably 1 to 3 parts by weight. Further, when the nonionic emulsifier and the anionic emulsifier are used in combination, the amount of the nonionic emulsifier used is more than 0 parts by weight, preferably 4 parts by weight, and preferably 0 parts by weight per 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, still more preferably 0.7 to 1.7 parts by weight, and 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. When used in combination with a nonionic emulsifier and an 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 preferably, 25/75 to 75/25 are even more preferable, 50/50 to 75/25 are even more preferable, and 65/35 to 75/25 are particularly preferable.

  As the polymerization initiator, azo compounds such as azobisisobutyronitrile; organic peroxides such as diisopropylbenzene hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide, benzoyl peroxide; sodium persulfate, persulfate Inorganic peroxides such as potassium, hydrogen peroxide and ammonium persulfate; and the like can be used. These polymerization initiators can be used alone or in combination of two or more kinds. 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 an organic peroxide and an inorganic peroxide as a polymerization initiator in combination with a reducing agent, as a redox polymerization initiator. The reducing agent used in combination is not particularly limited, but a compound containing a metal ion in a reduced state such as ferrous sulfate, sodium hexamethylenediaminetetraacetate, cuprous naphthenate; ascorbic acid, sodium ascorbate , Ascorbic acid (salt) such as potassium ascorbate; erythorbic acid (salt) such as erythorbic acid, sodium erysorbate, and potassium erysorbate; saccharides; sulfinates such as sodium hydroxymethanesulfinate; sodium sulfite, potassium sulfite, sulfite Sodium hydrogen, sodium aldehyde sulfite, potassium hydrogen sulfite sulfite; sodium pyrosulfite, potassium pyrosulfite, sodium pyrobisulfite, potassium pyrosulfite, etc. pyrosulfite; sodium thiosulfate, potassium thiosulfate, etc. thiosulfate Phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium phosphite (salt); pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, sodium pyrophosphite, pyrophosphite Pyrophosphorous acid (salt) such as potassium hydrogen phosphate; 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 part by weight, based on 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 salts, 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, based on 100 parts by weight of the monomer used for polymerization.

  At the time of emulsion polymerization, a polymerization auxiliary material such as a molecular weight adjusting agent, a particle size adjusting agent, a chelating agent and an oxygen scavenger can be used, if necessary.

  The emulsion polymerization may be carried out by any of batch method, semi-batch method and continuous method, but the semi-batch method is preferred. Specifically, in a reaction system containing a polymerization initiator and a reducing agent, a monomer used for the polymerization is continuously dropped into the polymerization reaction system from the initiation of the polymerization reaction to an arbitrary time, and the polymerization reaction is performed. At least one of the monomers used for the polymerization, the polymerization initiator, and the reducing agent is preferably subjected to the polymerization reaction while being continuously added dropwise to the polymerization reaction system from the initiation of the polymerization reaction to an arbitrary time, It is more preferable to carry out the polymerization reaction while continuously dropping all of the monomers, the polymerization initiator and the reducing agent used for the polymerization from the start of the polymerization reaction to an arbitrary time. By carrying out the polymerization reaction while continuously dropping these, emulsion polymerization can be stably carried out, whereby the polymerization reaction rate can be improved. The polymerization is usually carried out in the temperature range of 0 to 70 ° C, preferably 5 to 50 ° C.

  Further, when carrying out the polymerization reaction while continuously dropping the monomer used for the polymerization, the monomer used for the polymerization is mixed with an emulsifier and water to obtain a monomer emulsion (emulsion preparation). Step), it is preferable to continuously drop the monomer emulsion. The method for preparing the monomer emulsion is not particularly limited, and a method in which the total amount of the monomers used in the polymerization, the total amount of the emulsifier, and water are stirred using a stirrer such as a homomixer or a disk turbine can be used. 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, based on 100 parts by weight of the monomer used for the polymerization.

  When the polymerization reaction is continuously carried out while continuously dropping into the polymerization reaction system from the initiation of the polymerization reaction to an arbitrary time for all of the monomers used for the polymerization, the polymerization initiator, and the reducing agent, these are separated from each other. May be added dropwise to the polymerization system by using the dropping device, or at least the polymerization initiator and the reducing agent are mixed in advance and, if necessary, added to the polymerization system from the same dropping device as an aqueous solution state. May be. After completion of the dropping, the reaction may be continued for an arbitrary time in order to further improve the polymerization reaction rate.

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

  The method for containing the specific lubricant in the emulsion polymerization liquid is not particularly limited, and any method may be used as long as the emulsion polymerization liquid before coagulation can be in a state of containing the specific lubricant. .. For example, a specific lubricant may be added to the emulsion polymerization liquid after the emulsion polymerization, or a solution before the emulsion polymerization, specifically, a solution to be subjected to the emulsion polymerization (for example, a monomer for forming an acrylic rubber). Emulsion, containing a specific lubricant, by adding a specific lubricant to the monomer emulsion obtained by mixing the monomer with an emulsifier and water, and performing emulsion polymerization in the presence of the specific lubricant. You may obtain the liquid. Among these, from the viewpoint that the effect of the present invention can be further enhanced, it is preferable to add the specific lubricant to the emulsion polymerization liquid after the emulsion polymerization. The form of addition of the specific lubricant is not particularly limited, but when the specific lubricant is solid at room temperature, it may be added in the solid state or may be added in the molten state.

  According to the production method of the present invention, the specific lubricant is contained in the emulsion polymerization liquid before coagulation in advance, whereby the specific lubricant can be well dispersed in the emulsion polymerization liquid before coagulation. Therefore, the specific lubricant can be contained in the acrylic rubber after coagulation in a well-dispersed state. Then, as a result, the specific lubricant can be appropriately included in the obtained acrylic rubber (preferably, it can be included in a state of being uniformly dispersed), whereby the obtained acrylic rubber can be obtained. In addition, it can be excellent in handleability during 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, and drying. The effect can be fully exerted. On the other hand, when the 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 (especially, evenly). It cannot be contained in a dispersed state), and as a result, it becomes impossible to obtain the effect of blending the specific lubricant, that is, the effect of improving the handleability during drying and the roll processability.

  The addition amount 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 the amount 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 further preferably 0.2 to 0.3 parts by weight.

  Further, in the production method of the present invention, in addition to the specific lubricant, some of the compounding agents to be compounded into the acrylic rubber, specifically, the antiaging agent and / or the ethylene oxide polymer, are also coagulated. It is preferable to preliminarily contain the emulsion polymerization liquid before carrying out.

  For example, by preliminarily containing an antiaging 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, and thus, in the case of a rubber crosslinked product, effective tensile strength and elongation at break etc. It can be raised to. In addition, in the state of the emulsion polymerization liquid before performing the coagulation, by adding an antioxidant, since it is possible to appropriately disperse the antioxidant, even when the amount of the antioxidant is reduced, The effect of addition can be sufficiently exhibited. Specifically, the amount of the antioxidant added is preferably 0.1 to 2 parts by weight, more preferably 0.2 to 1.2 parts by weight, based on 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. Even with a relatively small blending amount, the effect of addition can be sufficiently exhibited. Incidentally, even when the anti-aging agent is contained in the emulsion polymerization liquid before coagulation, in the subsequent coagulation and washing, drying, etc., the added anti-aging agent is not substantially removed. The addition effect can be sufficiently exhibited. Further, as a method of containing an anti-aging agent in the emulsion polymerization liquid, after the emulsion polymerization, and a method of adding to the emulsion polymerization liquid before performing the coagulation, or a method of adding to the solution before performing the emulsion polymerization However, when added to the solution before carrying out the emulsion polymerization, aggregates are generated during the emulsion polymerization, which may cause fouling of the polymerization apparatus. In addition, the method of adding to the emulsion polymerization liquid before coagulation 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-butylphenol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 3- (3,3. 5-Di-tert-butyl-4-hydroxyphenyl) stearyl propionate, alkylated bisphenols, butylated sulfur-free phenolic antioxidants such as butylated reaction products of p-cresol and dicyclopentadiene; 2,4 -Bis [(octylthio) methyl] -6-methylphenol, 2,2'-thiobis- (4-methyl-6-t-butylphenol), 4,4'-thiobis- (6-t-butyl-o-cresol ), 2,6-di-t-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, and other thiophenol-based antioxidants; tris (nonylphenyl) ) Phosphite-based antioxidants such as phosphite, diphenylisodecyl phosphite, and tetraphenyldipropylene glycol / diphosphite; sulfur ester-based antioxidants such as dilauryl thiodipropionate; phenyl-α-naphthylamine, phenyl-β -Naphthylamine, p- (p-toluenesulfonylamide) -diphenylamine, 4,4 '-(α, α-dimethylbenzyl) diphenylamine, N, N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl- Amine-based antioxidants such as p-phenylenediamine and butyraldehyde-aniline condensates; 2-mercaptobenzimidazole and other imidazole antioxidants; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline And a quinoline antiaging agent such as; a hydroquinone antiaging agent such as 2,5-di- (t-amyl) hydroquinone; and the like. These antiaging agents may be used alone or in combination of two or more.

  Further, by preliminarily containing the ethylene oxide polymer in the emulsion polymerization liquid before coagulation, it is possible to improve the coagulability of the emulsion polymerization liquid, thereby reducing the amount of coagulant in the coagulation step. As a result, the residual amount in the finally obtained acrylic rubber can be reduced, and the compression set resistance and water resistance in the case of forming a rubber crosslinked product can be improved. The ethylene oxide polymer may be a polymer having a polyethylene oxide structure as a main chain structure, and is not particularly limited, and examples thereof include polyethylene oxide, polypropylene oxide, ethylene oxide / propylene oxide copolymer, and the like. 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, and still more preferably 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. 0.02 to 0.5 part 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 further preferably 20,000 to 120,000. As a method of incorporating the ethylene oxide polymer into the emulsion polymerization liquid, a method of adding the ethylene oxide polymer to the emulsion polymerization liquid after the emulsion polymerization and before the coagulation or a solution before performing the emulsion polymerization is added. There is a method.

  In addition, in the case of adding the antioxidant and / or the ethylene oxide polymer in addition to the specific lubricant to the emulsion polymerization liquid before coagulation, the addition order of these 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 in the emulsion polymerization step.

  The coagulant is not particularly limited, but examples thereof include a monovalent to trivalent metal salt. 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, and examples thereof include 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 and a metal selected from sodium, potassium, lithium, magnesium, calcium, zinc, titanium, manganese, iron, cobalt, nickel, aluminum and tin. Further, hydroxides of these metals can also be used.

  Specific examples of the 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; 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 and other nitrates; sodium sulfate , Potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, tin sulfate and the like; and the like. Among these, calcium chloride, sodium chloride, aluminum sulfate, magnesium chloride, magnesium sulfate, zinc chloride, zinc sulfate and sodium sulfate are preferable. Among them, 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 2 or more types.

  The amount of the coagulant used can reduce the residual amount of the coagulant in the finally obtained acrylic rubber while making the acrylic rubber coagulate sufficiently, and thus, in the case of a rubber cross-linked product, From the viewpoint of improving the compression set resistance and the water resistance, it 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. It is 3 to 20 parts by weight, and 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>
The production method of the present invention preferably further comprises a cleaning step of cleaning the hydrous crumb obtained in the coagulation step.

  The washing method is not particularly limited, but a method in which water is used as a washing liquid and the added water is mixed with the water-containing crumb to perform washing with water can be mentioned. 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.

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

  The number of times of washing with water is not particularly limited, and may be once, but is preferably 2 to 10 times, more preferably 3 to 8 from the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber. Times. From the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber, it is desirable that the number of times of washing with water is large, but even if the washing is performed beyond the above range, the effect of removing the coagulant is still high. On the other hand, although the number of steps is small, the number of steps is increased, and the decrease in productivity is greatly affected.

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

  The temperature at the time of acid washing 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 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 cleaning water used for acid cleaning can be determined, for example, by measuring the pH of water contained in the hydrous crumb after acid cleaning.

  It is preferable to further wash with water after performing the acid washing, and the conditions of washing with water may be the same as the above-mentioned conditions.

<Drying process>
Further, the production method of the present invention preferably further comprises a drying step of drying the hydrous crumbs washed in the washing step.

  The drying method in the drying step is not particularly limited, but for example, it can be dried using a dryer such as a screw type extruder, a kneader type dryer, an expander dryer, a hot air dryer or a reduced pressure dryer. .. Moreover, you may use the drying method which combined these. Further, 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., and 100 It is more preferable to set the temperature 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 produced in this manner 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 wt ppm or less, more preferably 7,000 wt ppm or less, and further preferably 5,000 wt. 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 it 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 of the crosslinked rubber can be made excellent. The residual amount of the coagulant can be determined by, for example, performing elemental analysis on the acrylic rubber and measuring the content of the element contained in the coagulant. Further, the method of setting the residual amount of the coagulant to the above-mentioned amount is not particularly limited, and a method of setting the amount of the coagulant to be in the above-described range, a method of adjusting the washing conditions, etc. Be done.

  Further, in the acrylic rubber of the present invention, the residual amount of the emulsifier contained in the acrylic rubber is preferably 22,000 weight ppm or less, more preferably 20,000 weight ppm or less, and further preferably 18,000 weight ppm. It is particularly preferably 17,000 ppm by weight or less. The lower limit of the residual amount of the emulsifier is not particularly limited, but is preferably 10 ppm by weight or more, more preferably 200 ppm by weight or more, and further preferably 500 ppm by weight or more. By setting the residual amount of the emulsifier in the acrylic rubber within the above range, it is possible to further improve the water resistance when the rubber cross-linked product is used. The residual amount of the emulsifier can be determined, for example, from the peak area of the molecular weight corresponding to the emulsifier in the measurement chart obtained by GPC measurement of acrylic rubber. The method for adjusting the residual amount of the emulsifier to the above-mentioned amount is not particularly limited, but, for example, as described above, the emulsifier is used in combination with a nonionic emulsifier and an anionic emulsifier, and the addition amount thereof is the above-mentioned amount. A method of setting the range is included.

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

  The cross-linking agent is not particularly limited, and examples thereof include polyvalent amine compounds such as diamine compounds, and their carbonates; sulfur; sulfur donors; triazine thiol compounds; polyvalent epoxy compounds; organic carboxylic acid ammonium salts; organic peroxides. Conventionally known crosslinking agents such as oxides; metal salts of dithiocarbamic acid; polycarboxylic acids; quaternary onium salts; imidazole compounds; isocyanuric acid compounds; organic peroxides; These crosslinking agents may be used alone or in combination of two or more. The cross-linking agent is preferably selected appropriately according to the type of cross-linkable 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 the carbonate thereof are not particularly limited, but the polyvalent amine compound having 4 to 30 carbon atoms and the carbonate thereof are preferable. Examples of such polyvalent amine compounds and their carbonates include aliphatic polyamine compounds, their carbonates, and aromatic polyamine compounds.

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

  Although it does not specifically limit as an aromatic polyvalent amine compound, For example, 4,4'- methylene dianiline, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino diphenyl ether, 3,4'-diamino diphenyl ether. 4,4 '-(m-phenylenediisopropylidene) dianiline, 4,4'-(p-phenylenediisopropylidene) dianiline, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, 4,4'-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, 1,3,5-benzenetriamine and the like can be mentioned. 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 to 100 parts by weight of the acrylic rubber. 2 to 4 parts by weight. By setting the content of the cross-linking agent within the above range, it is possible to make the rubber cross-linking material excellent in mechanical strength as a rubber cross-linked product.

  Further, the acrylic rubber composition of the present invention preferably further contains a crosslinking accelerator. The cross-linking accelerator is not particularly limited, but when the acrylic rubber of the present invention has a carboxyl group as a cross-linkable group, and the cross-linking 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, and aliphatic monovalent tertiary amine compounds. 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 alone or in combination of two or more.

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

  The aliphatic monovalent secondary amine compound is a compound obtained by substituting two hydrogen atoms of ammonia with an aliphatic hydrocarbon group. The aliphatic hydrocarbon group substituting the hydrogen atom preferably has 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 and dihexylamine. Heptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine, ditetradecylamine, dipentadecylamine, dicetylamine, di-2-ethylhexylamine, dioctadecylamine and the like.

  The aliphatic monovalent tertiary amine compound is a compound in which all three hydrogen atoms of ammonia are replaced with an aliphatic hydrocarbon group. The aliphatic hydrocarbon group substituting the hydrogen atom preferably has 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, tridodecylamine, and the like.

  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, based on 100 parts by weight of the acrylic rubber. Parts, particularly preferably 1 to 5 parts by weight. By setting the content of the crosslinking accelerator in the above range, the tensile strength and compression set resistance of the obtained rubber crosslinked product can be further improved.

  Further, the acrylic rubber composition of the present invention may be compounded with a compounding agent usually used in the rubber processing field, 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; antioxidants; light stabilizers; scorch inhibitors; plasticizers; processing aids. Agents, adhesives, lubricants, lubricants, flame retardants, antifungal agents, antistatic agents, colorants, crosslinking retardants, and the like. The compounding amount of these compounding agents is not particularly limited as long as it does not impair the object and effects of the present invention, and an amount according to the compounding purpose can be appropriately compounded.

  Further, the acrylic rubber composition of the present invention may further contain a rubber, an elastomer, a resin and the like other than the above-mentioned acrylic rubber of the present invention within a range not impairing the effects of the present invention. For example, rubbers other than acrylic rubbers such as acrylic rubbers other than the above-mentioned acrylic rubber of the present invention, natural rubbers, polybutadiene rubbers, polyisoprene rubbers, styrene-butadiene rubbers, acrylonitrile-butadiene rubbers, silicone rubbers, fluororubbers; 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. A resin such as a resin, a polycarbonate resin, a polyamide resin, a vinyl chloride resin, a fluororesin, or the like can be blended. The total amount of 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, and even more preferably 100 parts by weight of the acrylic rubber. It is 1 part by weight or less.

  Acrylic rubber composition of the present invention, the acrylic rubber, a cross-linking agent, and other various compounding agents used as necessary are mixed, mixed with a Banbury mixer or a kneader, kneading, then using a kneading roll, It is prepared by further kneading.

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

<Rubber cross-linked product>
The crosslinked rubber of the present invention is obtained by crosslinking the acrylic rubber composition of the present invention described above.
The rubber cross-linked product of the present invention is obtained by using the acrylic rubber composition of the present invention to perform molding with a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and heating. It can be produced by carrying out a cross-linking reaction to fix the shape as a rubber cross-linked product. In this case, the molding may be performed in advance and then crosslinked, or the molding and the crosslinking may be performed simultaneously. 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 rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

  The rubber cross-linked product of the present invention may be further heated for secondary cross-linking depending on the shape and size of the rubber cross-linked product. The secondary crosslinking varies depending on the heating method, the crosslinking temperature, the shape, etc., but is preferably 1 to 48 hours. The heating method and heating temperature may be appropriately selected.

  The rubber cross-linked product of the present invention thus obtained is used as a sealing material such as O-rings, packings, oil seals, and bearing seals in a wide range of fields such as transportation machines such as automobiles, general equipment, and electric equipment. It is preferably used as a gasket, a cushioning material, a vibration damping material, an electric wire coating material, industrial belts, tubes and hoses, sheets, and the like.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, "part" in each example is based on weight unless otherwise specified.
Various physical properties were evaluated according to the following methods.

[Moonie viscosity (ML1 + 4, 100 ° C)]
The Mooney viscosity (polymer Mooney) of 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 the GPC measurement, the integrated values of the peaks corresponding to the molecular weight of the specific lubricant used in the production were obtained, and these integrated values were compared with the integrated values of the peaks of the acrylic rubber, The content of the specific lubricant was calculated by calculating the weight ratio from the integrated value and the corresponding molecular weight.

[Probe tack test]
A probe tack test was performed on the acrylic rubber composition using a tacking tester (TAC-1000: manufactured by Reska Co., Ltd.). Specifically, with respect to an acrylic rubber sample molded into 30 mm × 20 mm × 2 mm, a SUS probe (10 mmφ) was pressed under conditions of a pressing speed of 0.05 mm / s, a pressing load of 20 gf, and a pressing holding time of 10 seconds. The pressing operation was performed, and then the tack strength (N) when the SUS probe was pulled up at a pulling rate of 15 mm / s was measured. It can be judged that the lower the tack strength, the lower the adhesiveness to the roll when processed by the 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 primary crosslinked by pressing at 170 ° C. for 20 minutes while applying a pressing pressure of 10 MPa, and then the obtained primary crosslinking The product was further heated in a gear type oven at 170 ° C. for 4 hours for secondary cross-linking to obtain a sheet-shaped rubber cross-linked product. The obtained rubber cross-linked product was punched with a No. 3 dumbbell to prepare a test piece. Next, using this test piece, tensile strength and elongation were measured according to JIS K6251.

[Bleed test]
Regarding the acrylic rubber composition, a sheet-shaped rubber cross-linked product was obtained under the same conditions as above. The obtained rubber cross-linked product was left standing at room temperature for 1 day and then visually judged. When bleeding, white powder or liquid-like substance can be confirmed on the surface of the rubber cross-linked product.
If bleeding occurs, it may cause stains when used as various materials and may damage equipment due to the bleeding substance.Therefore, if bleeding occurs, the intended use may be restricted. 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 container equipped with a homomixer, 46.294 parts of pure water, 49.3 parts of ethyl acrylate, 49.3 parts of n-butyl acrylate, 1.4 parts of mono-n-butyl fumarate, anionic surfactant. Lauryl sulfate (trade name "Emar 2FG", manufactured by Kao Corporation) 0.567 parts, polyoxyethylene dodecyl ether as a nonionic surfactant (trade name "Emulgen 105", weight average molecular weight: about 1500, Kao Corporation) 1.4 parts) and 0.25 parts of polyoxyethylene stearyl ether phosphoric acid (trade name "phosphanol RL-210", weight average molecular weight: about 500, manufactured by Toho Chemical Industry Co., Ltd.) as a lubricant. By stirring, a monomer emulsion was obtained.

  Then, 170.853 parts of pure water and 2.97 parts of the monomer emulsion obtained above were put into a polymerization reaction tank equipped with a thermometer and a stirrer, and the temperature was 12 ° C. under a nitrogen stream. Cooled down. Then, in a polymerization reaction tank, 145.54 parts of the monomer emulsion obtained above, 0.00033 part of ferrous sulfate as a reducing agent, 0.264 part 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. Then, while maintaining the temperature in the polymerization reaction tank at 23 ° C., the reaction was continued for 1 hour, and it was confirmed that the polymerization conversion rate reached 95%. Polymerization was performed by adding hydroquinone as a polymerization terminator. The reaction was stopped and an emulsion polymerization liquid was obtained.

  Then, with respect to 100 parts of the emulsion polymerization liquid obtained by the polymerization, stearyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an antiaging agent (trade name "Irganox 1076", BASF (Manufactured by the company) 0.3 parts (total of charged monomers used when manufacturing an emulsion polymerization solution (that is, total of ethyl acrylate, n-butyl acrylate, mono-n-butyl fumarate)) to 100 parts 1 part), and polyethylene oxide (weight average molecular weight (Mw) = 100,000) 0.011 part (0.039 based on 100 parts of the total amount of charged monomers used in the production of the emulsion polymerization liquid). Part) to obtain a mixed solution. Then, the obtained mixed solution was transferred to a coagulation tank, 60 parts of industrial water was added to 100 parts of this mixed solution, the temperature was raised to 85 ° C., and then the mixed solution 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, which was then filtered to obtain an acrylic resin. A hydrous crumb of rubber (A1) was obtained.

  Then, to 100 parts of the solid content of the hydrous crumb obtained above, 388 parts of industrial water was added, and the mixture was stirred at room temperature for 5 minutes in the coagulation tank, and then the water content was discharged from the coagulation tank. The crumbs were washed with water. In this production example, such washing with water was repeated 4 times.

  Then, an aqueous sulfuric acid solution (pH = 3) prepared by mixing 388 parts of industrial water and 0.13 part of concentrated sulfuric acid was added to 100 parts of the solid content of the water-containing crumb washed with water in the coagulation tank. After stirring at room temperature for 5 minutes, water was discharged from the coagulation tank to carry out pickling of the hydrous crumbs. The pH of the water-containing crumb after pickling (pH of water in the water-containing crumb) was measured to be pH = 3. Next, 388 parts of pure water was added to 100 parts of the solid content of the hydrous crumbs pickled, and the mixture was stirred at room temperature for 5 minutes in the coagulation tank, and then the water was discharged from the coagulation tank to obtain the hydrous crumbs. Was washed with pure water, and the hydrous crumb 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, no adhesion of acrylic rubber to the hot air dryer was observed.

  The obtained acrylic rubber (A1) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A1) is as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 1.4% by weight. Regarding the acrylic rubber (A1), the content of the lubricant in the acrylic rubber (A1) was measured according to the above method. The results are shown in Table 1.

[Production Example 2]
As Production Example 1 except that 0.25 part of a higher fatty acid (trade name “Moldwiz Int21G”, manufactured by Tomoe Kogyo Co., Ltd.) was used as the lubricant instead of 0.25 part of polyoxyethylene stearyl ether phosphate. 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 water-containing crumb of the acrylic rubber (A2), and the obtained acrylic was obtained. The water-containing crumb of rubber (A2) was washed with water, pickled, washed with pure water four times and dried with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1 to obtain a solid acrylic resin. A rubber (A2) was obtained. At this time, no adhesion of the acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer.

  The Mooney viscosity (ML1 + 4, 100 ° C.) of the obtained acrylic rubber (A2) is 33, and the composition of the acrylic rubber (A2) is as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 1.4% by weight. Regarding the acrylic rubber (A2), the content of the lubricant in the acrylic rubber (A2) was measured according to the above 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 added.

  Then, 170.853 parts of pure water and 2.97 parts of the monomer emulsion obtained above were put into a polymerization reaction tank equipped with a thermometer and a stirrer, and the temperature was 12 ° C. under a nitrogen stream. Cooled down. Then, in a polymerization reaction tank, 145.29 parts of the monomer emulsion obtained above, 0.00033 part of ferrous sulfate as a reducing agent, 0.264 part of sodium ascorbate as a reducing agent, polymerization 7.72 parts of a 2.85 wt% potassium persulfate aqueous solution (0.22 parts as the amount of potassium persulfate) as an initiator was continuously added dropwise over 3 hours. Then, while maintaining the temperature in the polymerization reaction tank at 23 ° C., the reaction was continued for 1 hour, and it was confirmed that the polymerization conversion rate reached 95%. Polymerization was performed by adding hydroquinone as a polymerization terminator. The reaction was stopped and an emulsion polymerization liquid was obtained.

  Then, with respect to 100 parts of the emulsion polymerization liquid obtained by the polymerization, stearyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an antiaging agent (trade name "Irganox 1076", BASF (Manufactured by the company) 0.3 parts (total of charged monomers used when manufacturing an emulsion polymerization solution (that is, total of ethyl acrylate, n-butyl acrylate, mono-n-butyl fumarate)) to 100 parts 1 part), polyethylene oxide (weight average molecular weight (Mw) = 100,000) 0.011 part (0.039 parts per 100 parts of the total amount of charged monomers used in the production of the emulsion polymerization liquid) ), And polyoxyethylene stearyl ether phosphoric acid (trade name "phosphanol RL-210", weight average molecular weight: about 500, manufactured by Toho Chemical Industry Co., Ltd.) as a lubricant, 0.075 part (when producing an emulsion polymerization liquid) A mixed solution was obtained by mixing 0.25 parts with respect to 100 parts in total of the charged monomers used in. Then, the obtained mixed solution was transferred to a coagulation tank, 60 parts of industrial water was added to 100 parts of this mixed solution, the temperature was raised to 85 ° C., and then the mixed solution 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, whereby the acrylic rubber (A3) To obtain a hydrous crumb.

  Then, the obtained water-containing crumb of the acrylic rubber (A3) is washed with water four times, pickled, washed with pure water and dried 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, no adhesion of acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer.

  The Mooney viscosity (ML1 + 4, 100 ° C.) of the obtained acrylic rubber (A3) is 33, and the composition of the acrylic rubber (A3) is as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 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 added to 100 parts by weight of the emulsion polymerization liquid obtained in the same manner as in Production Example 3, a higher fatty acid (trade name "Moldwiz Int21G", Tomoe) was used instead of 0.075 part of polyoxyethylene stearyl ether phosphoric acid. (Manufactured by Kogyo Co., Ltd.) in the same manner as in Production Example 3 except that 0.075 part (0.25 part with respect to 100 parts of the total amount of charged monomers used when manufacturing the emulsion polymerization liquid) was used A water-containing crumb of acrylic rubber (A4) was obtained by preparing a mixed solution and performing a coagulation operation.

  Next, the obtained water-containing crumb of acrylic rubber (A4) is washed with water four times, pickled, washed with pure water and dried 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, no adhesion of acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer.

  The obtained acrylic rubber (A4) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A4) is as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 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 compounding amount of polyoxyethylene stearyl ether phosphoric acid as a lubricant was changed from 0.25 part to 0.5 part. 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 water-containing crumb of the acrylic rubber (A5), and the obtained acrylic was obtained. The water-containing crumb of rubber (A5) was washed with water four times, washed with acid, washed with pure water, and dried with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1 to obtain a solid acrylic resin. A rubber (A5) was obtained. At this time, no adhesion of acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer.

  The resulting acrylic rubber (A5) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A5) is as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 1.4% by weight. Regarding the acrylic rubber (A5), the content of the lubricant in the acrylic rubber (A5) was measured according to the above 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 blending amount of higher fatty acid as a lubricant was changed from 0.25 part to 0.5 part. 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 water-containing crumb of the acrylic rubber (A6), and the obtained acrylic was obtained. The water-containing crumb of rubber (A6) was washed with water, pickled, washed with pure water four times and dried with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 2 to obtain a solid acrylic resin. A rubber (A6) was obtained. At this time, no adhesion of acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer.

  The Mooney viscosity (ML1 + 4, 100 ° C.) of the obtained acrylic rubber (A6) was 33, and the composition of the acrylic rubber (A6) was as follows: ethyl acrylate unit 49.3% by weight, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 1.4% by weight. Regarding the acrylic rubber (A6), the content of the lubricant in the acrylic rubber (A6) was measured according to the above 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 added to the emulsion polymerization liquid obtained in the same manner as in Production Example 3. By performing the operation, a water-containing crumb of acrylic rubber (A7) was obtained.

  Then, the obtained water-containing crumb of acrylic rubber (A7) is washed with water four times, pickled, washed with pure water and dried with a hot air dryer (belt conveyor type band dryer) in the same manner as in Production Example 1. Then, a solid acrylic rubber (A7) was obtained. In Production Example 7, the adhesion of the acrylic rubber to the hot air dryer was observed during the drying with the hot air dryer, and the workability was poor.

  The acrylic rubber (A7) thus obtained has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A7) is as follows: ethyl acrylate unit 49.3 wt%, n-butyl acrylate unit 49.3. %, And mono-n-butyl fumarate unit was 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 mixed with FEF carbon black (trade name "Shiest SO", manufactured by Tokai Carbon Co., Ltd.). At 60 ° C., 60 parts, 2 parts of stearic acid, and 2 parts of 4,4′-bis (α, α-dimethylbenzyl) diphenylamine (trade name “Nocrac CD”, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) were added. Mix for 5 minutes. Then, the obtained mixture was transferred to a roll at 50 ° C., 0.6 parts of hexamethylenediamine carbamate (trade name “Diak # 1”, an aliphatic polyamine compound manufactured by DuPont Dow Elastomer Co., Ltd.), and 1,3 Two parts of -di-o-tolylguanidine (trade name "NOXCELLER DT", a cross-linking accelerator manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) were mixed and kneaded to obtain an acrylic rubber composition.

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

[Examples 2 to 6, Comparative Example 1]
In the same manner as in Example 1 except that the acrylic rubber (A1) obtained in Production Example 1 was replaced with the acrylic rubbers (A2) to (A7) obtained in Production Examples 2 to 7, respectively. Table 2 shows the results obtained by similarly obtaining and measuring the rubber composition.

[Comparative Example 2]
Comparative Example 1 except that 0.3 part of polyoxyethylene stearyl ether phosphoric acid (trade name "phosphanol RL-210", weight average molecular weight: about 500, manufactured by Toho Chemical Industry Co., Ltd.) as a lubricant was further added. The acrylic rubber composition was obtained in the same manner, and the results of the same measurement and evaluation 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 a higher fatty acid (trade name "Moldwiz Int21G", manufactured by Tomoe Kogyo Co., Ltd.) as a lubricant was further added, and similarly measured and evaluated. The results obtained are shown in Table 2.

（＊１）単量体乳化液作製のための配合剤の添加量は、仕込み単量体１００部に対する配合量で示した。
（＊２）凝固前の乳化重合液に添加した配合剤の添加量は、乳化重合液１００部に対する配合量で示した。
（＊３）凝固工程で使用した凝固剤の添加量は、乳化重合液に、老化防止剤、ポリエチレンオキシド、および／または滑剤を添加することにより得られた混合液１００部に対する配合量で示した。

(* 1) The addition amount of the compounding agent for preparing the monomer emulsion is indicated by the compounding amount based on 100 parts of the charged monomer.
(* 2) The amount of the compounding agent added to the emulsion polymerization liquid before coagulation was shown as the amount to be mixed with 100 parts of the emulsion polymerization liquid.
(* 3) The addition amount of the coagulant used in the coagulation step is shown as the amount to be mixed with 100 parts of the mixed liquid obtained by adding the 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 phosphoric acid ester or a higher fatty acid, which is a lubricant (specific lubricant) prescribed by the present invention. Acrylic rubber containing a smooth lubricant does not cause adhesion of the acrylic rubber to the hot air dryer in the drying step and is excellent in handleability during drying, and is obtained by using such an acrylic rubber. The acrylic rubber composition had low tack strength in a probe tack test and was excellent in roll processability (Production Examples 1 to 6, Examples 1 to 6).
On the other hand, the acrylic rubber obtained in Production Example 7 does not contain the lubricant (specific lubricant) prescribed by the invention, and the acrylic rubber adheres to the hot air dryer in the drying step, so that Inferior in operability, further, an acrylic rubber composition obtained by using such an acrylic rubber has high tack strength in a probe tack test and is inferior in roll processability, and such a tendency is The same was true when a lubricant (specific lubricant) prescribed in the present invention was blended in preparing the acrylic rubber composition (Comparative Examples 1 to 3).

Claims (14)

A method for producing an acrylic rubber containing 0.1 to 0.4% by weight of a phosphoric acid ester as a lubricant,
By emulsion polymerizing the monomer for forming the acrylic rubber, an emulsion polymerization step of obtaining an emulsion polymerization liquid,
To the emulsion polymerization liquid before coagulation, a lubricant addition step of adding a phosphoric acid ester as the lubricant,
A method for producing an acrylic rubber, comprising a coagulation step of obtaining a hydrous crumb by adding a coagulant to the emulsion polymerization liquid and coagulating the emulsion polymerization liquid. The method for producing an acrylic rubber according to claim 1, wherein the phosphoric acid ester is polyoxyethylene higher alcohol phosphoric acid. The method for producing an acrylic rubber according to claim 2, wherein the polyoxyethylene higher alcohol phosphoric acid is polyoxyethylene stearyl ether phosphoric acid. The method for producing an acrylic rubber according to any one of claims 1 to 3 , wherein a content of the phosphoric acid ester as the lubricant in the acrylic rubber is 0.2 to 0.3% by weight. The acrylic rubber, the manufacturing method of the acrylic rubber according to any one of claims 1-4 content of the acrylic rubber component is 95 wt% or more. The acrylic rubber, the manufacturing method of the acrylic rubber according to any one of claims 1 to 5, which is a acrylic rubber containing a carboxyl group. 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 . The method for producing an acrylic rubber according to 1. The acrylic rubber according to claim 7 , wherein the amount of the lubricant added in the lubricant addition step is 0.2 to 0.3 parts by weight based on 100 parts by weight of the acrylic rubber component contained in the emulsion polymerization liquid. Manufacturing method. The method for producing an acrylic rubber according to claim 1 , 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. The method for producing an acrylic rubber according to claim 9 , wherein the amount of the nonionic emulsifier and the anionic emulsifier used is 50/50 to 75/25 in terms of a weight ratio of nonionic emulsifier / anionic emulsifier. In the emulsion polymerization step, the monomer for forming the acrylic rubber, the polymerization initiator and the reducing agent are subjected to an emulsion polymerization reaction while being continuously added dropwise to the polymerization reaction system from the initiation of the polymerization reaction to an arbitrary time. method for producing acrylic rubber according to any one of claims 1 to 10. A monomer for forming the acrylic rubber, in the state of a monomer emulsion obtained by mixing with an emulsifier and water, from the start of the polymerization reaction until any time, while continuously dropping into the polymerization reaction system The method for producing an acrylic rubber according to claim 11 , wherein an emulsion polymerization reaction is performed. A method for producing an acrylic rubber composition, comprising producing an acrylic rubber by the production method according to claim 1, and blending the produced acrylic rubber with a crosslinking agent. A method for producing a rubber cross-linked product, comprising producing an acrylic rubber composition by the method according to claim 13, and crosslinking the produced acrylic rubber.