JP6394834B1 - Acrylic rubber manufacturing method - Google Patents

Abstract

A method for producing an acrylic rubber, wherein the monomer for forming the acrylic rubber is subjected to emulsion polymerization to obtain an emulsion polymerization step of obtaining an emulsion polymerization solution, and the emulsion polymerization solution before coagulation is subjected to ethylene oxide. An acrylic oxide comprising: an ethylene oxide polymer addition step for containing a polymer, and a coagulation step for obtaining a water-containing crumb by adding a coagulant to the emulsion polymerization liquid adjusted to a temperature of 78 ° C. or more and coagulating it. A method for producing rubber is provided. ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the acrylic rubber which gives the rubber crosslinked material excellent in water resistance can be provided.

Description

  The present invention relates to a method for producing an acrylic rubber, and more particularly to a method for producing an acrylic rubber capable of giving a crosslinked rubber having excellent water resistance.

  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).

  On the other hand, in recent years, automobile members, such as seal materials, hose materials, vibration-proof materials, tube materials, belt materials or boot materials, are excellent in water resistance in addition to heat resistance and oil resistance. It is demanded. However, the conventional acrylic rubber such as the acrylic rubber described in Patent Document 1 does not necessarily have sufficient water resistance, and thus cannot meet the recent demand for water resistance.

JP-A-7-145291

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a method for producing an acrylic rubber capable of giving a crosslinked rubber having excellent water resistance.

  As a result of earnest research to achieve the above object, the present inventors have added an ethylene oxide polymer to an emulsion polymerization liquid before coagulation obtained by emulsion polymerization of a monomer for forming an acrylic rubber. After the addition, it was found that the above-mentioned object can be achieved by solidification at a solidification temperature of 78 ° C. or higher, and the present invention has been completed.

  That is, according to the present invention, there is provided a method for producing an acrylic rubber, wherein the monomer for forming the acrylic rubber is subjected to emulsion polymerization to obtain an emulsion polymerization solution, and before solidification. The step of adding an ethylene oxide-based polymer to the emulsion polymerization solution, and adding a coagulant to the emulsion polymerization solution adjusted to a temperature of 78 ° C. or more to solidify the hydrated crumb. And a coagulating step to provide an acrylic rubber manufacturing method.

  According to the present invention, there is also provided a method for producing an acrylic rubber, wherein the monomer for forming the acrylic rubber is mixed with an emulsifier and water to obtain a monomer emulsion. A step of adding an ethylene oxide polymer to the monomer emulsion prepared in the emulsion preparation step and an ethylene oxide polymer addition step in which the ethylene oxide polymer is added in the ethylene oxide polymer addition step A step of obtaining an emulsion polymerization solution by emulsion polymerization of monomers contained in the body emulsion, 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. A method for producing an acrylic rubber is provided.

In the production method of the present invention, the ethylene oxide polymer preferably has a weight average molecular weight of 10,000 or more, more preferably 10,000 to 200,000, and further preferably 20,000 to 120,000.
In the production method of the present invention, the ethylene oxide polymer is preferably an ethylene oxide homopolymer.
In the production method of the present invention, the addition amount of the ethylene oxide polymer in the ethylene oxide polymer addition step is 0.005 to 1 weight with respect to 100 parts by weight of the monomer for forming the acrylic rubber. Part, preferably 0.01 to 0.1 part by weight, and more preferably 0.02 to 0.06 part by weight.
In the manufacturing method of this invention, it is preferable that the solidification temperature in the said solidification process is 78-90 degreeC.
In the production method of the present invention, the emulsion polymerization of the monomer is preferably performed in the presence of a nonionic emulsifier and an anionic emulsifier, and the amount of the nonionic emulsifier and the anionic emulsifier used is determined as follows. More preferably, the weight ratio of the emulsifier is 50/50 to 75/25.
In the production method of the present invention, in the emulsion polymerization step, a monomer, a polymerization initiator, and a reducing agent for forming the acrylic rubber are continuously dropped into 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.
In the production method of the present invention, the monomer for forming the acrylic rubber is in the state of a monomer emulsion mixed with an emulsifier and water, from the start of the polymerization reaction to an arbitrary time from the polymerization reaction system. It is preferable to carry out the emulsion polymerization reaction while continuously dropping the solution.

Moreover, according to this invention, the manufacturing method of an acrylic rubber composition provided with the process of mix | blending a crosslinking agent with the acrylic rubber obtained by the said manufacturing method is provided.
Furthermore, according to this invention, the manufacturing method of the rubber crosslinked material provided with the process of bridge | crosslinking the acrylic rubber composition obtained by the said manufacturing method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the acrylic rubber which can give the rubber crosslinked material excellent in water resistance is provided.

<Acrylic rubber>
First, the acrylic rubber manufactured by the manufacturing method of this invention is demonstrated.
The acrylic rubber produced by the production method of the present invention is a (meth) acrylic acid ester as a main component in the molecule (in the present invention, it has 50% by weight or more in the total monomer units of rubber). Monomer [meaning acrylic acid ester monomer and / or methacrylic acid ester monomer. The same applies to methyl (meth) acrylate. ] A rubbery polymer containing units.

  The (meth) acrylic acid ester monomer that forms the (meth) acrylic acid ester monomer unit that is the main component of the acrylic rubber produced by the production method of the present invention is not particularly limited. ) Acrylic acid alkyl ester monomer and (meth) acrylic acid alkoxyalkyl ester monomer.

  Although it does not specifically limit as a (meth) acrylic-acid alkylester monomer, The ester of C1-C8 alkanol and (meth) acrylic acid is preferable, Specifically, (meth) acrylic acid methyl, ( (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.

  Although it does not specifically limit as a (meth) acrylic-acid alkoxyalkylester monomer, The ester of a C2-C8 alkoxyalkyl alcohol 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 , (Meth) acrylic acid 3-methoxypropyl, (meth) acrylic acid 4-methoxybutyl and the like. 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 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 produced by the production method of the present invention is usually 50 to 99.9% by weight, preferably 60 to 99.5% by weight. Preferably it is 70-99.5 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 produced by the production method of the present invention, as the (meth) acrylic acid ester monomer unit, 30 to 100% by weight of (meth) acrylic acid alkyl ester monomer unit, and (meth) acrylic It is preferable to use an acid alkoxyalkyl ester monomer unit composed of 70 to 0% by weight.

  The acrylic rubber produced by the production method of the present invention may contain a crosslinkable monomer unit, if necessary, in addition to the (meth) acrylic acid alkyl ester monomer unit. Although it does not specifically limit as a crosslinkable monomer which forms a crosslinkable monomer unit, For example, (alpha), (beta) -ethylenically unsaturated carboxylic acid monomer; Monomer which has an epoxy group; It has 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, and examples thereof include α, β- having 3 to 12 carbon atoms. Ethylenically unsaturated monocarboxylic acid, [alpha], [beta] -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and [alpha], [beta] -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and alkanol having 1 to 8 carbon atoms And monoesters. By using an 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. 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 acid having 4 to 12 carbon atoms and alkanol having 1 to 8 carbon atoms include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, malein Butenedionic acid mono-chain alkyl esters such as monomethyl acid, monoethyl maleate, mono-n-butyl maleate; monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, maleic acid Butenedionic acid monoesters having an alicyclic structure such as acid monocyclohexenyl; itaconic acid monoesters such as monomethyl itaconate, monoethyl itaconate, mono n-butyl itaconate, monocyclohexyl itaconate; and the like.
Among these, 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 An acid monoester is 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 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. , (Meth) acrylic acid 2-chloropropyl, (meth) acrylic acid 3-chloropropyl, (meth) acrylic acid 2,3-dichloropropyl, and the like.
Specific examples of (meth) acrylic acid haloacyloxyalkyl esters include 2- (chloroacetoxy) ethyl (meth) acrylate, 2- (chloroacetoxy) propyl (meth) acrylate, and 3- (chloro) (meth) acrylic acid. Acetoxy) propyl, 3- (hydroxychloroacetoxy) propyl (meth) acrylate, and the like.
Specific examples of (meth) acrylic acid (haloacetylcarbamoyloxy) alkyl esters include 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate and 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate. Is mentioned.

Specific examples of the halogen-containing unsaturated ether include chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, and 3-chloropropyl allyl ether.
Specific examples of the halogen-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone.
Specific examples of the halomethyl group-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, and p-chloromethyl-α-methylstyrene.

Specific examples of 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, p-vinylbenzyl chloroacetate and the like.

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, it is possible to improve the compression set resistance while improving the oil resistance and heat resistance.

  The content of the crosslinkable monomer unit in the acrylic rubber produced by the production method of the present invention is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, and still more preferably 0. 0.5 to 5% by weight. 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.

  The acrylic rubber produced by the production method of the present invention includes (meth) acrylic acid ester monomer units and other monomer units copolymerizable with these in addition to the crosslinkable monomer units used as necessary. You may have a unit of a mer. Examples of 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 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.

  The other monomer which can be copolymerized can be used individually by 1 type or in combination of 2 or more types. 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.

<Method for producing acrylic rubber>
Subsequently, the manufacturing method of the acrylic rubber of this invention is demonstrated.
The method for producing the acrylic rubber of the present invention comprises:
An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization of a monomer for forming an acrylic rubber; and
An ethylene oxide polymer addition step of containing an ethylene oxide polymer in the emulsion polymerization liquid before coagulation;
A coagulation step of obtaining a hydrous crumb by adding a coagulant to the emulsion polymerization liquid adjusted to a temperature of 78 ° C. or higher and coagulating.

  Alternatively, as a method for producing the acrylic rubber of the present invention, the emulsion polymerization step is performed by previously mixing a monomer for forming the acrylic rubber with an emulsifier and water to obtain a monomer emulsion (emulsion solution). Preparation step), in the state of the resulting monomer emulsion, emulsion polymerization can be carried out (emulsion polymerization step). In such an embodiment, for the monomer emulsion, It can also be set as the structure which performs emulsion polymerization, after adding an ethylene oxide type polymer.

<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 an 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 may 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 sulfosuccinic acid salt, alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, cationic emulsifiers such as ammonium chloride; and the like. 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, at least 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, coagulation described later can be achieved while effectively suppressing the occurrence of soiling due to adhesion of polymer aggregates to a polymerization apparatus (for example, a polymerization tank) during emulsion polymerization. It is possible to reduce the amount of coagulant used in the process, and as a result, the amount of coagulant in the finally obtained acrylic rubber can be reduced, and the water resistance of the resulting rubber cross-linked product can be further increased. Can be improved.

  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 amount of the emulsifier used is the total amount of the emulsifier used with respect to 100 parts by weight of the monomer used for the polymerization, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight. 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. 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. The use ratio in the case of using a combination of a nonionic emulsifier and an anionic emulsifier is preferably a nonionic emulsifier / anionic emulsifier weight ratio of 1/99 to 99/1, preferably 10/90 to 80/20. More preferably, 25/75 to 75/25 is more preferable, 50/50 to 75/25 is still more preferable, and 65/35 to 75/25 is particularly preferable.

  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 inorganic peroxide as a polymerization initiator in combination with a reducing agent as a redox polymerization initiator. 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 sulfite, potassium sulfite, sulfite 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. Although the usage-amount of a polymerization terminator is not specifically limited, Preferably it is 0.1-2 weight part with respect to 100 weight part of monomers used for superposition | 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 polymerization.

  In 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. In addition, superposition | polymerization is 0-70 degreeC normally, Preferably it is performed in the temperature range of 5-50 degreeC.

  In addition, when the polymerization reaction is performed while continuously dropping the monomer used for polymerization, the monomer used for polymerization is mixed with an emulsifier and water to form a monomer emulsion, It is preferable to drop continuously in the state of an 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 and 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.

<Ethylene oxide polymer addition process>
The ethylene oxide polymer addition step of the production method of the present invention is a step of adding an ethylene oxide polymer to the emulsion polymerization liquid before coagulation.

  The method for allowing the emulsion polymerization liquid to contain the ethylene oxide polymer is not particularly limited, and the emulsion polymerization liquid before coagulation can be in a state in which the ethylene oxide polymer can be contained. Anything is fine. For example, an ethylene oxide polymer may be added to the emulsion polymerization solution after emulsion polymerization, or a solution before emulsion polymerization, specifically, a solution for emulsion polymerization (for example, to form acrylic rubber) In the monomer emulsion obtained by mixing the monomer of (1) with an emulsifier and water, an ethylene oxide polymer is added, and emulsion polymerization is carried out in the presence of the ethylene oxide polymer, thereby producing ethylene oxide. An emulsion polymerization solution containing a polymer may be obtained. Among these, since the amount of a coagulant used in the coagulation step described later can be reduced, and thereby water resistance can be further increased, an ethylene oxide polymer is added to the emulsion polymerization liquid after emulsion polymerization. It is preferable to use such a mode. The addition form of the ethylene oxide polymer is not particularly limited, but when the ethylene oxide polymer is solid at room temperature, it may be added in a solid state or dissolved in a solvent such as water. You may add in a state.

  According to the production method of the present invention, an ethylene oxide polymer is preliminarily contained in an emulsion polymerization solution before coagulation, and coagulation in a coagulation step described later in the presence of such an ethylene oxide polymer. Is carried out at 78 ° C. or higher, the coagulability of the emulsion polymerization liquid can be improved, and thereby the amount of coagulant in the coagulation step can be reduced. And the residual amount of the coagulant | flocculant in the acrylic rubber finally obtained by this can be reduced, and water resistance in the case of setting it as a rubber crosslinked material can be improved more. In particular, according to the present inventors, when intensive studies were made on the relationship between the residual amount of the coagulant in the acrylic rubber and the water resistance of the resulting crosslinked rubber, the residual amount of the coagulant in the acrylic rubber was If the amount is too large, the water resistance of the resulting rubber cross-linked product will decrease, and the amount of coagulant used can be reduced by coagulating at a temperature of 78 ° C. or higher in the presence of an ethylene oxide polymer. It has been found that the residual amount of coagulant in rubber can be reduced.

  The ethylene oxide polymer may be a polymer having a polyethylene oxide structure as the main chain structure, and is not particularly limited, but is preferably a polymer consisting essentially of a polyethylene oxide structure. Examples thereof include polyethylene oxide, polypropylene oxide, ethylene oxide / propylene oxide copolymer, and among these, polyethylene oxide, that is, ethylene oxide homopolymer is preferable. 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.

  The addition amount of the ethylene oxide polymer in the ethylene oxide polymer addition step is preferably 0.005 to 1 part by weight, more preferably 0.006 to 0 with respect to 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. .6 parts by weight, more preferably 0.007 to 0.5 parts by weight, still more preferably 0.01 to 0.1 parts by weight, and particularly preferably 0.02 to 0.06 parts by weight.

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

  For example, the deterioration of acrylic rubber due to heat at the time of drying in the drying step described later can be effectively suppressed by preliminarily containing an anti-aging agent in the emulsion polymerization liquid before coagulation. 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 anti-aging agent 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 anti-aging 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-tert-butylfunol), 2,2′-methylene-bis (4-methyl-6-tert-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 products; 2,4-bis [(octylthio) methyl] -6-methylphenol, 2,2′-thiobis- (4-methyl-6-tert-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; dilauryl thiodipropionate Sulfur ester type antioxidants such as 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; And hydroquinone anti-aging agents such as 2,5-di- (t-amyl) hydroquinone. These anti-aging agents may be used alone or in combination of two or more.

  In addition, by previously containing a lubricant in the emulsion polymerization liquid before coagulation, the resulting acrylic rubber can be contained in a state in which the lubricant is well dispersed, and as a result, the resulting acrylic rubber Can be appropriately reduced, thereby preventing adhesion to the dryer during drying, improving operability during drying, and the resulting acrylic rubber, It can be excellent in roll processability. The addition amount of the lubricant 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 to 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. .2 to 0.3 parts by weight. Even if the lubricant is contained in the emulsion polymerization liquid before coagulation, the pre-blended lubricant is not substantially removed in the subsequent coagulation, washing, drying, etc. Even when it is contained, the effect of addition can be sufficiently exhibited.

  Although it does not specifically limit as a lubricant, Phosphate ester, fatty acid ester, fatty acid amide, higher fatty acid, etc. are mentioned. In addition, examples of the method for incorporating the lubricant into the emulsion polymerization liquid include a method of adding to the emulsion polymerization liquid after emulsion polymerization and before coagulation, and a method of adding to the solution before emulsion polymerization. It is done.

  In addition, the addition order in the case of adding an antioxidant and / or a lubricant in addition to the ethylene oxide polymer to the emulsion polymerization liquid before coagulation is not particularly limited, and may be appropriately selected.

<Coagulation process>
In the production method of the present invention, in the coagulation step, the emulsion polymerization solution obtained by the emulsion polymerization step is adjusted to a temperature of 78 ° C. or higher, and a coagulant is added to the emulsion polymerization solution adjusted to a temperature of 78 ° C. or higher. By doing so, it is a process of obtaining a hydrous crumb.

  In the production method of the present invention, an ethylene oxide polymer is previously contained in an emulsion polymerization solution before coagulation, and at a temperature of 78 ° C. or higher in the presence of such an ethylene oxide polymer. By performing the coagulation, the amount of coagulant in the coagulation step of the emulsion polymerization liquid can be reduced, so that the residual amount of the coagulant in the finally obtained acrylic rubber can be reduced. Water resistance can be further increased. If the coagulation temperature is too low, the coagulability of the emulsion polymerization solution will decrease, and the amount of coagulant necessary for coagulation will increase, resulting in the residual amount of coagulant in the acrylic rubber finally obtained. When the rubber cross-linked product is used, the water resistance decreases. In the production method of the present invention, the temperature (coagulation temperature) of the emulsion polymerization liquid during solidification is 78 ° C. or higher, preferably 79 ° C. or higher, more preferably 80 ° C. or higher. Moreover, the upper limit of the temperature of the emulsion polymerization liquid in coagulation is not particularly limited, but is usually 90 ° C. or lower.

  The coagulant is not particularly limited, and examples thereof include 1 to 3 metal salts. The 1-3 valent metal salt is a salt containing a metal that becomes a 1-3 valent 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 1 to 3 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 water resistance, it is preferably 1 to 100 parts by weight, more preferably 2 to 40 parts by weight, and even more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. Particularly preferred is 3 to 12 parts by weight.

<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 hydrous crumb obtained in the above-mentioned coagulation process.

  Although it does not specifically limit as a washing | cleaning method, The method of using water as a washing | cleaning liquid and performing water washing by mixing the added water with a water-containing crumb is mentioned. Although it does not specifically limit as temperature at the time of water washing, Preferably it is 5-60 degreeC, More preferably, it is 10-50 degreeC, and mixing time is 1-60 minutes, More preferably, it is 2-30 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 with respect to 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, but even if the washing exceeds the above range, the coagulant removing effect is effective. 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.

  Moreover, in the manufacturing method of this invention, after performing water washing, you may perform the acid washing | cleaning which uses an acid as a washing | cleaning liquid further. 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.

  Moreover, it is although it does not specifically limit as temperature at the time of acid washing, Preferably it is 5-60 degreeC, More preferably, it is 10-50 degreeC, and mixing time is 1-60 minutes, More preferably, it is 2-30 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. More preferably, it is set to -170 degreeC.

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

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

  In the acrylic rubber produced by the production method of the present invention, the residual amount of coagulant contained in the acrylic rubber is preferably 9,000 ppm by weight or less, more preferably 7,000 ppm by weight or less, Preferably it is 5,000 ppm by weight 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 water resistance in the case of a rubber cross-linked product can be further 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. The method of setting the residual amount of the coagulant as described above is not particularly limited. In addition to the method of coagulation in the coagulation step at a temperature of 78 ° C. or higher in the presence of an ethylene oxide polymer, coagulation is performed. Examples thereof include a method of setting the addition amount of the agent in the above-described range, and a method of adjusting the washing conditions as described above.

  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 acrylic rubber obtained by the above-described production method 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 produced by the production method of the present invention has an α, β-ethylenically unsaturated carboxylic acid monomer unit as a crosslinkable monomer unit, as a crosslinking agent, It is preferable to use a polyvalent amine compound and a carbonate thereof.

  Although it does not specifically limit as a polyvalent amine compound and its carbonate, A C4-C30 polyvalent amine compound and its carbonate are preferable. Examples of such polyvalent amine compounds and carbonates thereof include aliphatic polyvalent amine compounds, carbonates thereof, and aromatic polyvalent amine compounds.

  Although it does not specifically limit as an aliphatic polyvalent amine compound and its carbonate, For example, hexamethylene diamine, hexamethylene diamine carbamate, N, N'- dicinnamylidene-1,6-hexanediamine etc. are mentioned. Among these, hexamethylenediamine carbamate is preferable.

  Although it does not specifically limit as an aromatic polyvalent amine compound, 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, particularly preferably 0. 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 the acrylic rubber produced by the production method of the present invention has a carboxyl group as a crosslinkable group, and the crosslinking agent is a polyvalent amine compound or carbonic acid thereof. In the case of a salt, guanidine compound, diazabicycloalkene compound, imidazole compound, quaternary onium salt, tertiary phosphine compound, aliphatic monovalent secondary amine compound, aliphatic monovalent tertiary amine compound, etc. 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 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-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 with a 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 with a 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, and 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 this invention can mix | blend the compounding agent normally used in the rubber | gum processing field | area other than said each component. 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, rubbers other than acrylic rubbers such as acrylic rubbers 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.

  In addition, 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 cross-linking. 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.

  And since the rubber cross-linked product of the present invention obtained in this way is obtained using the acrylic rubber obtained by the production method of the present invention described above, it has excellent water resistance. Therefore, the rubber cross-linked product of the present invention makes use of such characteristics, for example, seals such as O-rings, packings, oil seals, bearing seals and the like in a wide range of transportation machines such as automobiles, general equipment, and electrical equipment. Materials: gaskets; cushioning materials, vibration-proof 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.

[Residual amount of coagulant]
The residual amount of coagulant in the acrylic rubber was measured by performing elemental analysis on the acrylic rubber using (ICP-AES). Specifically, the content ratio of the element contained in the used coagulant was determined by elemental analysis, and the residual amount of the coagulant was calculated from the determined content ratio.

[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.

[water resistant]
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. And it cut out into the test piece of 3 cm x 2 cm x 0.2 cm from the obtained sheet-like rubber cross-linked product, and according to JIS K6258, the obtained test piece was adjusted to a temperature of 80 ° C for 70 hours in distilled water. A dipping test was performed, and the volume change rate of the test piece before and after dipping was measured according to the following formula. It can be judged that the smaller the volume change rate before and after the immersion, the lower the swelling with respect to water, and the better the water resistance.
Volume change rate before and after immersion (%) = (Volume of test piece after immersion−Volume of test piece before immersion) ÷ Volume of test piece before immersion × 100

[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 0.567 parts of sodium lauryl sulfate (trade name “Emar 2FG”, manufactured by Kao Corporation), and polyoxyethylene dodecyl ether (trade name “Emulgen 105”, non-ionic surfactant), weight average molecular weight: about 1500, A monomer emulsion was obtained by charging 1.4 parts of Kao Corporation and stirring.

  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, 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, for 100 parts of the emulsion polymerization solution obtained by polymerization, polyethylene oxide (weight average molecular weight (Mw) = 100,000, weight average molecular weight is measured using GPC in a DMF solvent containing 10 mmol LiBr). 0.11 part (total of the monomers used in the production of the emulsion polymerization liquid (that is, the total of ethyl acrylate, n-butyl acrylate and mono-n-butyl fumarate) of 100 parts by weight) 039 parts), 3- (3,5-di-tert-butyl-4-hydroxyphenyl) stearyl propionate (trade name “Irganox 1076”, manufactured by BASF) as an anti-aging agent, 0.3 part (emulsion polymerization solution) 1 part for a total of 100 parts of the monomers used in the production of the product, and polyoxyethylene stearyl ether phosphate (quotient as a lubricant) Name “Phosphanol RL-210”, weight average molecular weight: about 500, manufactured by Toho Chemical Co., Ltd.) 0.075 parts (based on a total of 100 parts of the charged monomers used in producing the emulsion polymerization liquid) 0.25 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 80 ° C., and then the mixed liquid was stirred at a temperature of 80 ° 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 The water-containing crumbs that had been washed with pure water were dried at 110 ° C. for 1 hour with a hot air dryer to obtain a solid acrylic rubber (A1).

  The resulting acrylic rubber (A1) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A1) 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 unit of 1.4% by weight. Moreover, about the acrylic rubber (A1), the residual amount of the coagulant | flocculant in acrylic rubber (A1) was measured according to the said method. The results are shown in Table 1.

[Production Example 2]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, in the same manner as in Production Example 1, the mixture obtained by mixing an anti-aging agent, polyethylene oxide and a lubricant was used at the time of coagulation. A water-containing crumb of acrylic rubber (A2) was obtained by performing a solidification operation in the same manner as in Production Example 1 except that the temperature of the mixed solution was 85 ° C.

  Next, the water-containing crumb of the obtained acrylic rubber (A2) is subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1, so that solid acrylic rubber is obtained. (A2) was obtained. The resulting acrylic rubber (A2) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33. The acrylic rubber (A2) 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 unit of 1.4% by weight. Moreover, the residual amount of the coagulant in the acrylic rubber (A2) was measured according to the above method. The results are shown in Table 1.

[Production Example 3]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, in the same manner as in Production Example 1, the mixture obtained by mixing an anti-aging agent, polyethylene oxide and a lubricant was used at the time of coagulation. A water-containing crumb of acrylic rubber (A3) was obtained by performing a solidification operation in the same manner as in Production Example 1 except that the temperature of the mixed liquid was 90 ° C.

  Next, the water-containing crumb of the obtained acrylic rubber (A3) is subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1 to obtain a solid acrylic rubber. (A3) was obtained. 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 unit of 1.4% by weight. Further, the residual amount of the coagulant in the acrylic rubber (A3) was measured according to the above method. The results are shown in Table 1.

[Production Example 4]
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”, manufactured by Kao Corporation) as a nonionic surfactant , And 0.039 part of polyethylene oxide (weight average molecular weight (Mw) = 100,000) were charged and stirred to obtain a monomer emulsion.

  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, 145.32 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.

  And with respect to 100 parts of emulsion polymerization liquid obtained by superposition | polymerization, stearyl 3- (3,5- di-tert- butyl-4-hydroxyphenyl) propionate (brand name "Irganox 1076", BASF) as an anti-aging agent 0.3 parts (1 part for a total of 100 parts of the charged monomers used in the production of the emulsion polymerization solution) and polyoxyethylene stearyl ether phosphate (trade name “Phos”) as a lubricant By mixing 0.075 part of “Fanol RL-210” (manufactured by Toho Chemical Co., Ltd.) (0.25 part with respect to a total of 100 parts of charged monomers used in producing the emulsion polymerization liquid). A mixture was obtained. And the water-containing crumb of acrylic rubber (A4) is performed by performing the solidification operation in the same manner as in Production Example 1 except that the temperature of the liquid mixture at the time of solidification is 85 ° C. with respect to the obtained liquid mixture. Obtained.

  Next, the water-containing crumb of the obtained acrylic rubber (A4) was subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1 to obtain a solid acrylic rubber. (A4) was obtained. The resulting acrylic rubber (A4) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A4) is 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono n-butyl fumarate unit of 1.4% by weight. Further, the residual amount of the coagulant in the acrylic rubber (A4) was measured according to the above method. The results are shown in Table 1.

[Production Example 5]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, in the same manner as in Production Example 1, the mixture obtained by mixing an anti-aging agent, polyethylene oxide and a lubricant was used at the time of coagulation. Same as Production Example 1 except that the temperature of the mixed solution was 70 ° C. and the amount of sodium sulfate as a coagulant was 10 parts (33.3 parts with respect to 100 parts of the polymer contained in the mixed solution). Thus, a water-containing crumb of acrylic rubber (A5) was obtained by performing a solidification operation. In Production Example 5, the amount of sodium sulfate as a coagulant is increased from 3.3 parts to 10 parts compared to Production Example 1, but solidification can be achieved only by increasing the amount of sodium sulfate. This is because there was not (the same applies to Production Examples 6 to 8 described later).

  Next, the water-containing crumb of the obtained acrylic rubber (A5) was subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1, thereby solid acrylic rubber. (A5) was obtained. The resulting acrylic rubber (A5) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A5) is 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono n-butyl fumarate unit of 1.4% by weight. Further, the residual amount of the coagulant in the acrylic rubber (A5) was measured according to the above method. The results are shown in Table 1.

[Production Example 6]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, in the same manner as in Production Example 1, the mixture obtained by mixing an anti-aging agent, polyethylene oxide and a lubricant was used at the time of coagulation. Same as Production Example 1 except that the temperature of the mixed solution was 75 ° C. and the amount of sodium sulfate as a coagulant was 10 parts (33.3 parts with respect to 100 parts of the polymer contained in the mixed solution). Then, a water-containing crumb of acrylic rubber (A6) was obtained by performing a solidification operation.

  Next, the water-containing crumb of the obtained acrylic rubber (A6) was subjected to four times of water washing, pickling, pure water washing, and drying with a hot air dryer in the same manner as in Production Example 1 to obtain a solid acrylic rubber. (A6) was obtained. 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 unit of 1.4% by weight. Moreover, the residual amount of the coagulant in the acrylic rubber (A6) was measured according to the above method. The results are shown in Table 1.

[Production Example 7]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, mixing in the same manner as in Production Example 1 except that polyethylene oxide was not added to the emulsion polymerization solution obtained in the same manner as in Production Example 1. A liquid was obtained, and the temperature of the liquid mixture at the time of coagulation was set to 85 ° C. and the amount of sodium sulfate as a coagulant was 10 parts (100 parts of polymer contained in the liquid mixture). A water-containing crumb of acrylic rubber (A7) was obtained by performing the coagulation operation in the same manner as in Production Example 1 except that the amount was 33.3 parts.

  Next, the water-containing crumb of the obtained acrylic rubber (A7) was subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1 to obtain a solid acrylic rubber. (A7) was obtained. The resulting acrylic rubber (A7) has a Mooney viscosity (ML1 + 4, 100 ° C.) of 33, and the composition of the acrylic rubber (A7) is 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono n-butyl fumarate unit of 1.4% by weight. Moreover, the residual amount of the coagulant in the acrylic rubber (A7) was measured according to the above method. The results are shown in Table 1.

[Production Example 8]
Using the emulsion polymerization solution obtained in the same manner as in Production Example 1, instead of 0.011 part of polyethylene oxide, the polyoxyethylene dodecyl ether (trade name) was obtained in the same manner as in Production Example 1. "Emulgen 105", weight average molecular weight: about 1500, a compound in which a dodecyl group is bonded to a polyoxyethylene structure, manufactured by Kao Co., Ltd. 0.011 part (prepared monomer used in producing an emulsion polymerization liquid) Except for using 0.039 parts for 100 parts in total), a mixed solution was obtained in the same manner as in Production Example 1, and the temperature of the mixed solution at the time of solidification was 85 ° C. with respect to the obtained mixed solution. And the coagulation operation is performed in the same manner as in Production Example 1 except that the amount of sodium sulfate as a coagulant is 10 parts (33.3 parts with respect to 100 parts of the polymer contained in the mixed solution). Acrylic rubber A hydrous crumb (A8) was obtained.

  Next, the water-containing crumb of the obtained acrylic rubber (A8) was subjected to four times of water washing, pickling, pure water washing and drying with a hot air dryer in the same manner as in Production Example 1 to obtain a solid acrylic rubber. (A8) was obtained. The resulting acrylic rubber (A8) had a Mooney viscosity (ML1 + 4, 100 ° C.) of 34, and the composition of the acrylic rubber (A8) was 49.3% by weight of ethyl acrylate units and 49.3% of n-butyl acrylate units. % By weight and mono n-butyl fumarate unit of 1.4% by weight. Moreover, the residual amount of the coagulant in the acrylic rubber (A8) was measured according to the above method. The results are shown in Table 1.

[Example 1]
Using a Banbury mixer, 100 parts of the acrylic rubber (A1) obtained in Production Example 1, 30 parts of clay (trade name “Satinton Clay 5A”, manufactured by Takehara Chemical Industry Co., Ltd., calcined kaolin), silica (trade name “ Carplex 1120 ", manufactured by Evonik) 15 parts, silica (trade name" Carplex 67 ", manufactured by Evonik) 35 parts, stearic acid 2 parts, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine ( 2 parts of the product name “NOCRACK CD”, manufactured by Ouchi Shinsei Chemical Co., Ltd. and 1 part of 3-methacryloxypropyltrimethoxysilane (trade name “KBM-503”, manufactured by Shin-Etsu Silicone Co., Ltd., silane coupling agent) Add and mix at 50 ° C. 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 -An acrylic rubber composition was obtained by blending and kneading 2 parts of di-o-tolylguanidine (trade name "Noxeller DT", manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., crosslinking accelerator).

  And according to the said method, each measurement and evaluation of tensile strength, elongation, and water resistance were performed using the obtained acrylic rubber composition. The results are shown in Table 2.

[Examples 2 to 4]
In place of the acrylic rubber (A1) obtained in Production Example 1, acrylic rubbers (A2) to (A4) obtained in Production Examples 2 to 4 were used, respectively. Table 2 shows the results of measurement and evaluation in the same manner after obtaining the rubber composition.

[Comparative Examples 1-4]
In place of the acrylic rubber (A1) obtained in Production Example 1, acrylic rubbers (A5) to (A8) obtained in Production Examples 5 to 8 were used, respectively. Table 2 shows the results of measurement and evaluation in the same manner after obtaining the rubber composition.

（＊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 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, Production Example 1 in which an ethylene oxide polymer was added to the emulsion polymerization solution before coagulation, and coagulation was performed at a temperature of 78 ° C. or higher in the presence of the ethylene oxide polymer. The rubber cross-linked product obtained using the acrylic rubber obtained according to 4 was excellent in water resistance (Production Examples 1 to 4 and Examples 1 to 4).

On the other hand, although an ethylene oxide polymer was added to the emulsion polymerization liquid before coagulation, rubber crosslinking obtained by using the acrylic rubber obtained in Production Examples 5 and 6 coagulated at a temperature of less than 78 ° C. The product was inferior in water resistance (Production Examples 5 and 6, Comparative Examples 1 and 2).
Moreover, the acrylic polymer obtained by the manufacture example 7 which did not add an ethylene oxide type polymer to the emulsion polymerization liquid before coagulating, or the manufacture example 8 which used polyoxyethylene dodecyl ether instead of the ethylene oxide type polymer. The rubber cross-linked product obtained using rubber was also inferior in water resistance (Production Examples 7 and 8, Comparative Examples 3 and 4).

Claims (14)

A method for producing acrylic rubber, comprising:
An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization of the monomer for forming the acrylic rubber; and
An ethylene oxide polymer addition step of adding an ethylene oxide polymer having a weight average molecular weight of 10,000 to 200,000 to the emulsion polymerization liquid before coagulation;
A coagulating step of obtaining a hydrous crumb by adding a coagulant and coagulating the emulsion polymerization liquid adjusted to a temperature of 78 ° C. or higher. A method for producing acrylic rubber, comprising:
An emulsion preparation step for obtaining a monomer emulsion by mixing the monomer for forming the acrylic rubber with an emulsifier and water;
An ethylene oxide polymer addition step of adding an ethylene oxide polymer having a weight average molecular weight of 10,000 to 200,000 to the monomer emulsion prepared in the emulsion preparation step;
A step of obtaining an emulsion polymerization solution by emulsion polymerization of a monomer contained in the monomer emulsion added with the ethylene oxide polymer in the ethylene oxide polymer 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. The method for producing an acrylic rubber according to claim 1 or 2 , wherein the ethylene oxide polymer has a weight average molecular weight of 20,000 to 120,000. The method for producing an acrylic rubber according to any one of claims 1 to 3 , wherein the ethylene oxide polymer is an ethylene oxide homopolymer. The addition amount of the ethylene oxide polymer in the ethylene oxide polymer addition step is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer for forming the acrylic rubber. 4. The method for producing acrylic rubber according to any one of 4 above. The addition amount of the ethylene oxide polymer in the ethylene oxide polymer addition step is 0.01 to 0.1 parts by weight with respect to 100 parts by weight of the monomer for forming the acrylic rubber. 5. A method for producing acrylic rubber according to 5 . The addition amount of the ethylene oxide polymer in the ethylene oxide polymer addition step is 0.02 to 0.06 parts by weight with respect to 100 parts by weight of the monomer for forming the acrylic rubber. 6. A method for producing acrylic rubber according to 6 . The method for producing acrylic rubber according to any one of claims 1 to 7 , wherein a coagulation temperature in the coagulation step is 78 to 90 ° C. The method for producing an acrylic rubber according to any one of claims 1 to 8 , wherein the emulsion polymerization of the monomer is performed in the presence of a nonionic emulsifier and an anionic emulsifier. The method for producing 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 a weight ratio of nonionic emulsifier / anionic emulsifier. 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 manufacturing method of the acrylic rubber in any one of Claims 1-10 . 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 11 , wherein an emulsion polymerization reaction is performed. The process according to claim 1 to the acrylic rubber obtained by the production method according to any one of 12, acrylic rubber composition comprising a step of mixing a crosslinking agent. A method for producing a crosslinked rubber comprising a step of crosslinking an acrylic rubber composition obtained by the production method according to claim 13 .