JP6683189B2 - Acrylic rubber manufacturing method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing an acrylic rubber, and more particularly, to a method for producing an acrylic rubber in which scorch during processing is effectively suppressed and thereby excellent in processing stability.

  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 that constitutes the acrylic rubber, adding a coagulant to the obtained emulsion-polymerized liquid to coagulate, and drying the hydrous crumb obtained by coagulation. It is manufactured by doing. At this time, rubber such as acrylic rubber is dried by various methods, but from the viewpoint of productivity, a drying method using an extrusion dryer is known (for example, refer to Patent Document 1).

  On the other hand, as in the technique described in Patent Document 1, when the acrylic rubber is dried using an extrusion dryer, scorch tends to occur when the acrylic rubber obtained is mixed with a crosslinking agent or the like. There was a problem.

Japanese Patent No. 3665870

  The present invention has been made in view of such circumstances, and an object thereof is to provide a manufacturing method for manufacturing an acrylic rubber having excellent processing stability in which scorch during processing is effectively suppressed. And

  The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object. As a result, the water-containing crumb of acrylic rubber is dried by an extrusion-type dryer, and the cooling rate in cooling the dried rubber after drying is set within a predetermined range. As a result, they have found that the above object can be achieved, and have completed the present invention.

  That is, according to the present invention, a method for producing an acrylic rubber, the step of drying the water-containing crumb of the acrylic rubber by an extrusion-type dryer, extruded from the extrusion-type dryer, the dried rubber discharged, And a step of cooling to 40 ° C. or less, and when cooling the dried rubber, an acrylic resin having a cooling rate of 40 ° C./hour or more when cooled to 40 ° C. after being discharged from the extrusion dryer. A method of making rubber is provided.

In the production method of the present invention, when the dry rubber is extruded from the extrusion dryer, it is extruded from the extrusion dryer as a sheet-shaped rubber having a thickness of 9 mm or more, and the dry rubber is cooled in a sheet shape. It is preferable.
In the production method of the present invention, it is preferable that the acrylic rubber contains a (meth) acrylic acid alkoxyalkyl ester monomer unit.
Further, according to the present invention, there is provided a method for producing an acrylic rubber composition, which comprises a step of adding a crosslinking agent to the acrylic rubber obtained by any of the above production methods.
Further, according to the present invention, there is provided a method for producing a rubber crosslinked product, which comprises a step of crosslinking the acrylic rubber composition obtained by the above production method.

  ADVANTAGE OF THE INVENTION According to this invention, the scorch at the time of processing is suppressed effectively, and the manufacturing method for manufacturing the acrylic rubber excellent in processing stability by this can be provided.

FIG. 1 is a diagram showing an example of an extrusion-type dryer used in the manufacturing method of the present invention. FIG. 2 is a diagram showing an example of a transport-type cooling device used in the manufacturing method of the present invention.

<Acrylic rubber>
First, the acrylic rubber produced by the production method of the present invention will be described.
The acrylic rubber produced by the production method of the present invention has, as a main component (in the present invention, a component contained in an amount of 50% by weight or more in all the monomer units constituting the acrylic rubber) in the molecule. (Meth) acrylic acid ester monomer [means acrylic acid ester monomer and / or methacrylic acid ester monomer. Hereinafter, the same applies to methyl (meth) acrylate and the like. ] It is a rubber-like polymer containing units.

  The (meth) acrylic acid ester monomer forming the (meth) acrylic acid ester monomer unit, which is the main component of the acrylic rubber produced by the production method of the present invention, is not particularly limited, but, for example, (meth ) Acrylic acid alkyl ester monomers and (meth) acrylic acid alkoxyalkyl ester monomers can be mentioned.

  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, methyl (meth) acrylate, ( 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, 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are more preferable, and 2-methoxyethyl acrylate is preferable. Ethyl is particularly preferred. 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 produced by the production method of the present invention is usually 50 to 99.9% by weight, preferably 60 to 99.5% by weight, It is preferably 70 to 99.5% by weight. If the content of the (meth) acrylic acid ester monomer unit is too small, the weather resistance, heat resistance, and oil resistance of the obtained rubber crosslinked product may be decreased, while if it is too large, the rubber crosslinked obtained. The heat resistance of the product may decrease.

  In addition, in the acrylic rubber produced by the production method of the present invention, as a (meth) acrylic acid ester monomer unit, from the viewpoint that the effect of the present invention, that is, the effect of improving the scorch during processing is greater, It is preferable to use one containing at least a (meth) acrylic acid alkoxyalkyl ester monomer unit, preferably 1 to 50% by weight, more preferably 5 to 50% by weight of a (meth) acrylic acid alkoxyalkyl ester monomer unit. It is preferably contained in an amount of 45% by weight, particularly preferably 10 to 40% 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. 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 may be, for example, C3-12 α, β- 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 enhanced.

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 the monoester 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 maleic acid. 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, a monoester of an α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkanol having 1 to 8 carbon atoms is preferable, and a butenedioic acid mono-chain alkyl ester or a 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 maleate 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-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, but examples thereof include unsaturated alcohol ester of halogen-containing saturated carboxylic acid, (meth) acrylic acid haloalkyl ester, (meth) acrylic acid haloacyloxyalkyl ester, (meth) acryl. Examples thereof 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 unsaturated alcohol esters of halogen-containing saturated carboxylic acids include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate.
Specific examples of the haloalkyl (meth) acrylate 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 the (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, and p-chloromethyl-α-methylstyrene.

Specific examples of the halogen-containing unsaturated amide include N-chloromethyl (meth) acrylamide.
Specific examples of the haloacetyl group-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether and p-vinylbenzyl 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, and piperylene.
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. By using a carboxyl group-containing acrylic rubber as the 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 further preferably 0. 0.5 to 5% by weight. 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 produced by the production method of the present invention includes, in addition to the (meth) acrylic acid ester monomer unit and the crosslinkable monomer unit used as necessary, other monomer copolymerizable therewith. It may have units of a monomer. Examples of 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 monomers 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.

<Method for producing acrylic rubber>
Next, a method for producing the acrylic rubber of the present invention will be described.
The manufacturing method of the acrylic rubber of the present invention,
A step of drying the water-containing crumb of acrylic rubber with an extrusion-type dryer,
A step of cooling the dried rubber extruded from the extrusion type dryer and discharged to 40 ° C. or lower,
When the dried rubber is cooled, it is discharged from the extrusion dryer and then cooled to 40 ° C. at a cooling rate of 40 ° C./hour or more.

  The water-containing crumb of acrylic rubber used in the production method of the present invention is, for example, an emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization of a monomer for forming an acrylic rubber, and the obtained emulsion polymerization. It can be produced by adding a coagulant to the liquid and performing a coagulation step of obtaining a water-containing crumb of 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 standard method.

  The emulsifier is not particularly limited, polyoxyethylene alkyl ether such as polyoxyethylene dodecyl ether, polyoxyethylene alkylphenol ether such as polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ester such as polyoxyethylene stearic acid ester, Nonionic emulsifiers such as polyoxyethylene sorbitan alkyl esters and polyoxyethylene polyoxypropylene copolymers; salts of fatty acids such as myristic acid, palmitic acid, oleic acid and linolenic acid; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate. , Higher alcohol sulfate salts such as sodium lauryl sulfate, higher phosphate salts such as sodium alkyl phosphate ester, alkyl sulfoco And the like; anionic emulsifiers such as click salt, alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, cationic emulsifiers such as ammonium chloride. These emulsifiers can be used alone or in combination of two or more 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, nonionic emulsifiers and anionic emulsifiers are preferable, and it is preferable to use nonionic emulsifiers and anionic emulsifiers in combination. By using a combination of a nonionic emulsifier and an anionic emulsifier, it is used in the coagulation step 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 increasing the water resistance of the obtained acrylic rubber. .

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

  The amount of the emulsifier used is a total amount of the emulsifier to be used, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, further preferably 1 to 3 parts by weight, based on 100 parts by weight of the monomer used for the polymerization. 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 or less, preferably 0 parts by weight, relative 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, 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 or less, 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 the nonionic emulsifier and the anionic emulsifier are used in combination, the weight ratio of the nonionic emulsifier / anionic emulsifier is preferably 1/99 to 99/1, and preferably 10/90 to 80/20. 65/35 to 75 are more preferable, 25/75 to 75/25 are still more preferable, 50/50 to 75/25 are still more preferable, and 65/35 to 75 are more preferable from the viewpoint of more appropriately preventing the fouling of the polymerization apparatus during the polymerization. / 25 is 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.

  Further, the organic peroxide and the inorganic peroxide as the polymerization initiator are preferably used as a redox polymerization initiator in combination with a reducing agent. 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; sulfinic acid salts such as sodium hydroxymethanesulfinate; sodium sulfite, potassium sulfite, sulfite Sodium hydrogen, aldehyde sodium hydrogensulfite, potassium sulfite sulfite; sodium pyrosulfite, potassium pyrosulfite, sodium pyrobisulfite, potassium pyrosulfite, and other pyrosulfite; sodium thiosulfate Thiosulfates such as potassium thiosulfate; phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, phosphorous acid (salt) of potassium hydrogen phosphite; pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, Examples include pyrophosphorous acid (salt) such as sodium hydrogen pyrophosphite and potassium hydrogen pyrophosphite; sodium formaldehyde sulfoxylate. These reducing agents may 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, hydroxylamine sulfate, diethylhydroxylamine, hydroxylamine sulfonic 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 monomer 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 initiation 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 form a monomer emulsion, It is preferable to continuously drop in the state of an 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 by 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, and more preferably 20 to 50 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

  Further, 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 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 as an aqueous solution from the same dropping device. 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.

  Next, a coagulant is added to the emulsion polymerization liquid obtained in the emulsion polymerization step to obtain a water-containing crumb of acrylic rubber.

  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, more preferable are calcium chloride, sodium chloride, magnesium sulfate, and sodium sulfate, and magnesium sulfate is more preferable from the viewpoint that scorch can be prevented more appropriately. , Sodium sulfate. 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 allowing the acrylic rubber to coagulate sufficiently. From the viewpoint of improving compression set resistance and 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. 3 to 20 parts by weight, particularly preferably 3 to 12 parts by weight.

  The solidification temperature is not particularly limited, but is preferably 50 to 90 ° C, more preferably 60 to 90 ° C, and further preferably 78 to 90 ° C.

  Further, in the present invention, a part of the compounding agents to be compounded with the acrylic rubber in the emulsion polymerization liquid before the coagulating agent is added and coagulated, specifically, an antiaging agent, a lubricant and an ethylene oxide-based compounding agent. At least one of the polymers is preferably contained in advance. That is, it is preferable that at least one of the antiaging agent, the lubricant, and the ethylene oxide polymer is already mixed in the emulsion polymerization liquid, and the emulsion polymerization liquid containing these components is solidified.

  For example, by preliminarily containing an anti-aging agent in the emulsion polymerization liquid before coagulation, the anti-aging agent can be blended in the state of the emulsion polymerization liquid before coagulation. The anti-aging agent can be appropriately dispersed in the composition, so that even if the compounding amount of the anti-aging agent is reduced, the effect of adding the anti-aging agent 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 or 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 coagulation, a method of adding to the solution before performing the emulsion polymerization However, when added to the solution before carrying out the emulsion polymerization, it may cause contamination of the polymerization apparatus, etc., after the emulsion polymerization, and in the emulsion polymerization liquid before performing the coagulation The method of addition is preferred.

  The anti-aging agent is not particularly limited, but is not a sulfur atom-containing phenol anti-aging agent; thiophenol anti-aging agent; phosphite anti-aging agent; sulfur ester anti-aging agent; amine anti-aging agent; Examples include imidazole anti-aging agents; quinoline anti-aging agents; hydroquinone anti-aging agents. These antioxidants may be used alone or in combination of two or more.

  Further, by preliminarily containing the lubricant in the emulsion polymerization liquid before coagulation, the obtained acrylic rubber can contain the lubricant in a well-dispersed state. As a result, the obtained acrylic rubber It is possible to appropriately reduce the tackiness of, and thereby, the roll processability can be made more excellent. The amount of the lubricant added is preferably 0.1 to 0.4 parts by weight, more preferably 0.15 to 0.3 parts by weight, and even more preferably 0 based on 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. .2 to 0.3 parts by weight. Even when the lubricant is contained in the emulsion polymerization liquid before coagulation, in the subsequent coagulation, washing, drying, etc., the lubricant preliminarily blended is not substantially removed, and therefore, in the emulsion polymerization liquid. Even when it is contained, the effect of its addition can be sufficiently exhibited.

  The lubricant is not particularly limited, and examples thereof include phosphoric acid ester, fatty acid ester, fatty acid amide, and higher fatty acid. Further, as a method of containing a lubricant in the emulsion polymerization liquid, after the emulsion polymerization, and a method of adding to the emulsion polymerization liquid before performing the coagulation, a method of adding to the solution before performing the emulsion polymerization. To be

  Furthermore, by preliminarily containing the ethylene oxide polymer in the emulsion polymerization liquid before solidification, the solidification property of the emulsion polymerization liquid can be improved, thereby reducing the amount of the coagulant in the solidification step. Therefore, the residual amount in the finally obtained acrylic rubber can be reduced, and the water resistance in the case of forming a rubber cross-linked product can be improved. The ethylene oxide polymer is not particularly limited as long as it has 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. Ethylene 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 parts by weight. The weight average molecular weight of the ethylene oxide polymer is preferably 10,000 to 1,000,000, more preferably 10,000 to 200,000, and 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 the emulsion polymerization is added. There is a method.

  The order in which the anti-aging agent, the lubricant and the ethylene oxide polymer are added in advance to the emulsion polymerization liquid before solidification is not particularly limited and may be appropriately selected.

  Then, even when these antioxidants, lubricants and / or ethylene oxide polymers are previously contained in the emulsion polymerization liquid before coagulation, the coagulant is added to the emulsion polymerization liquid under the same conditions as above. By carrying out the coagulation operation in this way, a hydrous crumb can be obtained.

  Further, the water-containing crumb of acrylic rubber obtained through the coagulation step may be washed as necessary.

  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.

  The amount of water added to the hydrous crumb during washing with water 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 washing with respect to 100 parts by weight of the solid content (mainly the acrylic rubber component) contained in the water-containing crumb is preferably 50 to 9,800 parts by weight, more preferably 300 to 1,800. 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 high. On the other hand, although the number of steps is small, the increase in the number of steps has a large effect on the decrease in productivity.

  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 large. The acid used for the 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 preferable to add it in the state of an aqueous solution, preferably pH = 6 or less, more preferably pH = 4 or less, still more preferably pH = 3 or less. It is preferable to add it in the form of an aqueous solution. 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 washing water for acid washing is not particularly limited, but is preferably pH = 6 or less, more preferably pH = 4 or less, still more preferably pH = 3 or less. The pH of the cleaning water for acid cleaning can be determined by, for example, 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 those described above.

  Then, in the production method of the present invention, the water-containing crumb of the acrylic rubber thus obtained is dried by an extrusion-type dryer, and then the dried rubber extruded from the extrusion-type dryer is discharged to 40 Acrylic rubber (solid acrylic rubber) is obtained by cooling to below ℃.

  The extrusion type dryer used for drying the water-containing crumb of acrylic rubber is not particularly limited, but dehydration and drying by kneading is possible, and thus any extruder capable of dehydrating and drying the water-containing crumbs may be used. Although not particularly limited, for example, a single-screw or twin-screw extruder can be used, and it is preferable to use a twin-screw extruder from the viewpoint of drying efficiency.

  In the manufacturing method of the present invention, for example, the extrusion dryer 1 shown in FIG. 1 can be used.

  The extruder dryer 1 shown in FIG. 1 is a twin-screw extruder including a pair of screws (not shown) inside a barrel 3. As shown in FIG. 1, the barrel 3 of the extrusion dryer 1 includes a drive unit 2 and 15 divided barrel blocks 31 to 45. Inside the barrel 3, a supply zone 100 and a dehydration zone are provided. The drying zone 102 and the drying zone 104 are sequentially formed from the upstream side to the downstream side of the barrel 3.

  The supply zone 100 is an area for supplying a slurry containing a hydrous crumb into the barrel 3. The dehydration zone 102 is an area for separating and discharging a liquid (serum water) containing a coagulant and the like from a slurry containing a hydrous crumb. The drying zone 104 is an area for drying the dehydrated crumb.

  In the extrusion dryer 1, the insides of the barrel blocks 31 and 32 correspond to the supply zone 100, the insides of the barrel blocks 33 to 37 correspond to the dehydration zone 102, and the insides of the barrel blocks 38 to 45 correspond to the drying zone 104. To do. The number of installed barrel blocks is not particularly limited to the embodiment shown in FIG. 1, and may be an appropriate number according to the water-containing crumb of acrylic rubber to be dried.

  A feed port 310 that receives a water-containing crumb is formed in the barrel block 31 that constitutes the supply zone 100. The barrel blocks 34 and 37 that form the dehydration zone 102 are provided with discharge slits 340 and 370 for discharging the water contained in the water-containing crumb. Further, vent ports 390, 410, 430, 450 for deaeration are formed in the barrel blocks 39, 41, 43, 45 constituting the drying zone 104, respectively.

  Inside the barrel 3, a pair of screws are arranged. To drive the pair of screws, drive means such as a motor housed in the drive unit 2 are connected to drive the pair of screws, whereby the pair of screws are rotatably held. The pair of screws is preferably a biaxial meshing type in which a mountain portion and a valley portion are meshed with each other, whereby the dehydration and drying efficiency of the water-containing crumb can be enhanced. Further, the pair of screws may rotate in the same direction or in different directions, but from the viewpoint of self-cleaning performance, a type in which they rotate in the same direction is preferable. The screw shape of the pair of screws is not particularly limited, and may be a shape required for each zone of the supply zone 100, the dehydration zone 102, and the drying zone 104, and is not particularly limited.

  Further, a die 4 for extruding the dried rubber dehydrated and dried in the barrel 3 into a sheet shape is connected to the downstream side of the barrel block 45 described above.

  Then, the slurry containing the water-containing crumb of acrylic rubber obtained through the coagulation step is introduced into the supply zone 100 from the feed port 310 after being dehydrated by an expeller as necessary. The water-containing crumb contained in the slurry containing the water-containing crumb introduced into the supply zone 100 is pushed to the downstream side of the supply zone 100 by the rotation of the screw provided in the barrel 3. The temperature inside the supply zone 100 is not particularly limited, but is preferably 30 to 100 ° C, more preferably 40 to 100 ° C. By setting the temperature of the supply zone within the above range, the viscosity of the hydrous crumb becomes appropriate, and the extrudability of the hydrous crumb is improved.

  The water-containing crumb introduced into the supply zone 100 is sent to the dehydration zone 102 by the rotation of the screw. In the dehydration zone 102, the water contained in the water-containing crumb is drained from the slits 340 and 370 provided in the barrel blocks 34 and 37. The temperature inside the dehydration zone 102 is preferably 50 to 100 ° C, more preferably 80 to 100 ° C.

  The water-containing crumb dehydrated in the dehydration zone 102 is sent to the drying zone 104 by the rotation of the screw. The crumb sent to the drying zone 104 is plasticized and kneaded by the rotation of the screw to become a melt, which generates heat and is carried to the downstream side while raising the temperature. When the melt reaches the vent ports 390, 410, 430, 450 provided in the barrel blocks 39, 41, 43, 45, the pressure is released, so that the water contained in the melt is separated and vaporized. To be done. The separated vaporized water (steam) is discharged to the outside through a vent pipe (not shown). The temperature inside the drying zone 104 is preferably 100 to 200 ° C, more preferably 110 to 190 ° C. The internal pressure is about 1000 to 5000 kPa.

  By passing through the drying zone 104, the dried crumb is delivered to the outlet side by the screw and introduced into the die 4, where it is extruded as a sheet-shaped dry rubber and discharged from the extrusion dryer 1. . At this time, the water content of the dried rubber is preferably 1% by weight or less, more preferably 0.7% by weight or less, and further preferably 0.5% by weight or less. The thickness of the sheet-shaped dry rubber discharged from the extrusion dryer 1 is not particularly limited, but a viewpoint of suppressing a decrease in productivity due to a decrease in drying speed due to an excessively small thickness, and From the viewpoint of reducing the load on the extrusion dryer 1 due to the increase in pressure loss to reduce the thickness, it is preferably 9 mm or more, more preferably 13 mm or more, and further preferably It is 15 mm or more. The upper limit of the thickness of the sheet-shaped dry rubber discharged from the extrusion dryer 1 is not particularly limited, but is preferably 50 mm or less, more preferably from the viewpoint of cooling efficiency when cooling the dry rubber described below. Is 35 mm or less.

  Then, in the production method of the present invention, the dry rubber extruded by an extrusion dryer such as the extrusion dryer 1 shown in FIG. 1 is cooled to 40 ° C. or lower to obtain an acrylic rubber (solid acrylic rubber). ) Get. Further, in the production method of the present invention, the cooling rate at the time of performing this cooling, specifically, the temperature of the dry rubber is cooled to 40 ° C. from the time when the dry rubber is extruded from the extrusion dryer and discharged. The cooling rate at that time is 40 ° C./hour or more. According to the production method of the present invention, the cooling rate when the dry rubber is cooled to 40 ° C. from the time when the dry rubber is extruded from the extruder and discharged, is set to 40 ° C./hour or more. By this, the scorch of the obtained acrylic rubber during processing is effectively suppressed, and thus the processing stability can be improved.

In addition, in the manufacturing method of the present invention, when the dry rubber is extruded from the extrusion dryer and discharged, when the temperature of the dry rubber is cooled to 40 ° C., when the cooling rate is V1, cooling is performed. The speed V1 (unit: ° C / hour) is the temperature T1 (unit: ° C) of the dried rubber at the time of being discharged from the extrusion dryer and the time when the temperature of the dried rubber is discharged from the extrusion dryer. It is obtained according to the following formula (1) from the time P1 (unit: time) required to decrease to 40 ° C.
Cooling rate V1 (° C./hour)={temperature T1-40 at the time of extrusion from the extrusion dryer} / time P1 required to decrease to 40 ° C. (1)
For example, the temperature T1 at the time of being extruded from the extrusion dryer is 160 ° C., and the time P1 required for the dried rubber to be lowered to 40 ° C. from the time of being discharged from the extrusion dryer has a time P1 of 0.5 hours. In case of, the cooling rate V1 is 240 ° C./hour. In the manufacturing method of the present invention, the cooling rate V1 is obtained from the temperature T1 and the time P1. Therefore, in the manufacturing method of the present invention, the cooling rate V1 is calculated from the temperature T1 and the time P1. The cooling may be performed under the condition that the cooling rate is 40 ° C./hour or more. For example, the temperature gradient when the temperature is lowered from T1 to 40 ° C. is not necessarily constant. For example, the temperature gradient due to cooling may be relatively large in the initial stage of cooling, while the temperature gradient due to cooling may be relatively small in the latter period of cooling.

  In the production method of the present invention, the dry rubber is extruded from the extrusion-type dryer and discharged, so that the cooling rate V1 when the temperature of the dry rubber is cooled to 40 ° C. is 40 ° C./hour or more. The dried rubber may be cooled. The cooling rate V1 is preferably 50 ° C./hour or more, more preferably 60 ° C./hour or more, and the upper limit of the cooling rate V1 is not particularly limited, but is usually 400 ° C. / Hour or less.

  Further, in the production method of the present invention, extruded from the extrusion type dryer, the method for cooling the discharged dry rubber is not particularly limited, for example, for the dry rubber, a method of cooling by cooling air, Examples thereof include a method of spraying water on the dry rubber and a method of water cooling such as immersing the dry rubber in water. Further, these may be used in combination, and for example, a method of blowing cooling air after cooling with water cooling may be adopted. In the method of blowing cooling air to cool, the temperature of the cooling air used for cooling may be lower than room temperature (23 ° C), preferably 1 to 22 ° C, more preferably 5 to 22 ° C. In the water cooling method, the temperature of water used for cooling is preferably 1 to 22 ° C, more preferably 5 to 21 ° C. When cooling is performed by using a method of blowing cooling air or a method of blowing water, the blowing amount (output at the time of blowing) is not particularly limited, and the thickness of the dry rubber and the target cooling It may be set appropriately according to the speed V1. Among the methods of cooling by blowing cooling air and the methods of cooling by water, the method of blowing cooling air to cool is more preferable from the viewpoint that the amount of water in the obtained dried rubber can be more appropriately reduced.

  Further, in the manufacturing method of the present invention, when cooling the dry rubber that is extruded from the extrusion dryer and discharged, it is required when the dry rubber is reduced to 40 ° C. from the time when the dry rubber is discharged from the extrusion dryer. From the viewpoint of production efficiency, the time P1 is preferably 2.5 hours or less, more preferably 1.5 hours or less, and further preferably 1 hour or less.

  In the production method of the present invention, the method of cooling the discharged dry rubber extruded from the extrusion type dryer is not particularly limited, and the dry rubber is extruded from the extrusion type dryer, and from the time of discharge. A method may be adopted in which the cooling rate V1 when the temperature of the dried rubber is cooled to 40 ° C. is 40 ° C./hour or more. For example, a specific example in the case of cooling by blowing cooling air As an example of the specific embodiment, there is a method of using the transport cooling device 5 as shown in FIG.

The transport cooling device 5 shown in FIG. 2 is installed, for example, in a state of being directly connected to the dry rubber discharge port of the die 4 of the extrusion dryer 1 shown in FIG. 1 or in the vicinity of the dry rubber discharge port. a cooling system of the transport equation, the sheet-shaped dry rubber discharged from the die 4 of the extrusion-type dryer 1, at conveyor 51, while conveying in the direction of the arrow in FIG. 2, with respect to the dry rubber, cooling means The device is capable of cooling the dry rubber by blowing cooling air from 52 . The cooling unit 52 is not particularly limited, but, for example, cooling air sent from a cooling air generation unit (not shown) is supplied to the dry rubber on the conveyor 51 from a plurality of cooling ports provided on the conveyor 51 side. And the like, which have a structure that can be sprayed.

  Further, a cutting mechanism (not shown) is attached to the downstream side of the conveyance type cooling device 5 shown in FIG. 2, and the cooled sheet-shaped dry rubber is cut at a predetermined interval to obtain a predetermined size. Acrylic rubber sheet can be used.

The length L1 of the conveyor 51 and the cooling means 52 of the transport cooling device 5 (the length of the portion to which cooling air can be blown) L1 is not particularly limited, but is, for example, 10 to 100 m, preferably 20 to 50. is there. Further, in the conveyance type cooling device 5, the conveyance speed of the dry rubber is the length L1 of the conveyor 51 and the cooling means 52 , the discharge speed of the dry rubber discharged from the extrusion dryer, the target cooling speed V1, and the time. Although it may be appropriately adjusted according to P1, it is, for example, 10 to 100 m / hour, more preferably 15 to 70 m / hour. The transport cooling device 5 is not particularly limited to the configuration including one conveyor 51 and one cooling means 52 as shown in FIG. 2, and two or more conveyors 51 and two or more cooling devices corresponding thereto are provided. It may be configured to include the means 52 . In this case, the lengths of the two or more cooling means 52 may be set within the above range.

  According to the manufacturing method of the present invention, the acrylic rubber (solid acrylic rubber) can be obtained as described above.

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

  In the above description, the extrusion type dryer 1 shown in FIG. 1 is used to dry the water-containing crumb of acrylic rubber, and the conveyance type cooling device 5 shown in FIG. 2 is used to cool the dried rubber. However, the extrusion dryer is not limited to such an embodiment, and an extrusion dryer capable of dehydrating and drying the water-containing crumb of acrylic rubber by kneading is used as the extrusion dryer. Any method may be used, and any method may be used for cooling the dried rubber as long as the cooling rate V1 can be 40 ° C./hour or more.

<Acrylic rubber composition>
The acrylic rubber composition of the present invention comprises the acrylic rubber obtained by the above-mentioned production method of the present invention and a crosslinking agent.

  The cross-linking agent is not particularly limited, and examples thereof include polyvalent amine compounds such as diamine compounds, and carbonates thereof; sulfur; sulfur donors; triazine thiol compounds; polyvalent epoxy compounds; organic carboxylic acid ammonium salts; organic peroxides. Conventionally known crosslinking agents such as oxides; metal salts of dithiocarbamic acid; polyvalent carboxylic acids; quaternary onium salts; imidazole compounds; isocyanuric acid compounds; organic peroxides; These cross-linking agents can 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 produced by the production method of the present invention has an α, β-ethylenically unsaturated carboxylic acid monomer unit as the crosslinkable monomer unit, as a crosslinking agent, It is preferable to use a polyvalent amine compound and its carbonate.

  The polyvalent amine compound and its carbonate salt are not particularly limited, but a polyvalent amine compound having 4 to 30 carbon atoms and its carbonate salt are preferable. Examples of such polyvalent amine compounds and their carbonates include aliphatic polyamine compounds, their carbonates, and aromatic polyamine compounds.

  Although it does not specifically limit as an aliphatic polyvalent amine compound and its carbonate, For example, hexamethylenediamine, hexamethylenediaminecarbamate, N, N'-dicinnamylidene-1,6-hexanediamine, etc. are mentioned. 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. It is 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 and to have excellent mechanical strength as a rubber cross-linked product.

  Further, 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 crosslinking group, and the crosslinking agent is a polyvalent amine compound, or a carbonic acid thereof. When it is a salt, a guanidine compound, a diazabicycloalkene compound, an imidazole compound, a quaternary onium salt, a tertiary phosphine compound, an aliphatic monovalent secondary amine compound, and an 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 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 in which two 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 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, and dioctadecylamine.

  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, it is possible to further improve the tensile strength and the compression set resistance of the obtained rubber crosslinked product.

  In addition to the above components, the acrylic rubber composition of the present invention may contain a compounding agent that is commonly used in the rubber processing field. 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 the object or effect of the present invention is not impaired, and an appropriate amount can be compounded according to the compounding purpose.

  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 that does not impair 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; olefin rubbers Elastomers, styrene elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, polysiloxane elastomers, and other 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, or a fluororesin may be blended. The total compounding amount of rubber, elastomer, and resin other than the above-mentioned acrylic rubber of the present invention 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 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, kneaded, and 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, is added at a temperature at which reaction or decomposition does not occur. It is preferable to mix in a short time.

<Rubber crosslinked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the above-mentioned acrylic rubber composition of the present invention.
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 manufactured by carrying out a cross-linking reaction to fix 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 rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

  Further, depending on the shape and size of the rubber cross-linked product, the rubber cross-linked product of the present invention may be further heated for secondary cross-linking. 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 for O-rings, packings, oil seals, bearing seals, etc. in a wide range of fields such as transportation machinery such as automobiles, general equipment, electric equipment and the like. Suitably used as gaskets, cushioning materials, anti-vibration materials, electric wire coating materials, 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 of the acrylic rubber (polymer Mooney) and the Mooney viscosity of the acrylic rubber composition (Compound Mooney) were measured according to JIS K6300.

[Water content of acrylic rubber after drying and cooling]
The water content (heat loss) of the acrylic rubber after drying and cooling was measured according to the "oven method" defined in JIS K6238-1. Specifically, 10 g of the dried and cooled acrylic rubber was placed in an oven at 105 ± 5 ° C. and dried until the mass was substantially unchanged, and the amount of mass reduction before and after the drying was calculated. Then, the mass reduction rate was obtained from the calculated mass reduction amount, and this was taken as the water content (heat loss) (unit: wt%).

[Moonies coach]
The Mooney scorch of the acrylic rubber composition was measured at a temperature of 125 ° C. according to JIS K 6300, and the Mooney scorch time t5 (unit: minutes) and the minimum viscosity Vm were determined. The larger the Mooney scorch time t5, the better the scorch stability.

[Normal physical properties (tensile strength, elongation, 100% tensile stress, hardness)]
The acrylic rubber composition is placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and primary cross-linking is performed by pressing at 170 ° C. for 20 minutes while applying a pressure of 10 MPa. 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 JIS No. 3 type dumbbell to prepare a test piece. Then, the obtained test piece was used to determine the tensile strength, elongation and 100% tensile stress of the rubber cross-linked product according to JIS K6251 and the rubber cross-linked product using Durometer hardness tester type A according to JIS K6253. The hardness was measured respectively.

[Production Example 1]
In a mixing container equipped with a homomixer, 46.294 parts of pure water, 5 parts of ethyl acrylate, 63 parts of n-butyl acrylate, 30 parts of 2-methoxyethyl acrylate, 2 parts of mono-n-butyl maleate, anionic 0.567 parts of sodium lauryl sulfate (trade name "Emar 2FG", manufactured by Kao) as a surfactant, and polyoxyethylene dodecyl ether (trade name "Emulgen 105", manufactured by Kao) as a nonionic surfactant 1.4 parts were charged and stirred to obtain a monomer emulsion.

  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, 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, the reaction was continued for 1 hour while maintaining the temperature in the polymerization reaction tank at 23 ° C, and it was confirmed that the polymerization conversion rate reached 97%, and 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 antioxidant (trade name "Irganox 1076", BASF (Manufactured by the same company) 0.3 part (total of charged monomers used in producing emulsion polymerization liquid (that is, ethyl acrylate, n-butyl acrylate, 2-methoxyethyl acrylate 10 parts, mono maleic acid) 1 part to 100 parts by weight of n-butyl), 0.011 part of polyethylene oxide (weight average molecular weight (Mw) = 100,000) (total of charged monomers used when producing an emulsion polymerization solution) 0.039 parts per 100 parts), and polyoxyethylene stearyl ether phosphoric acid as a lubricant (trade name "phosphanol RL-210", Toho Chemical Co., Ltd.) A mixed solution was obtained by mixing 0.075 part (manufactured by Gakukogyo Co., Ltd.) (0.25 part with respect to 100 parts in total of the charged monomers used when the emulsion polymerization solution was manufactured). Then, the obtained mixed liquid was transferred to a coagulation tank, 60 parts of industrial water was added to 100 parts of this mixed liquid, the temperature was raised to 85 ° C., and then the mixed liquid was stirred at a temperature of 85 ° C. However, by continuously adding 3.3 parts of sodium sulfate as a coagulant (11 parts to 100 parts of the polymer contained in the mixed solution), the polymer is coagulated and then filtered off. , A hydrous crumb 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 water was discharged from the coagulation tank. The wet crumb was 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 that had been washed with water in the coagulation tank. After stirring at room temperature for 5 minutes, water was discharged from the coagulation tank to pickle the hydrous crumbs. The pH of the water-containing crumb after pickling (pH of water in the water-containing crumb) was measured and found to be pH = 3. Next, 388 parts of pure water was added to 100 parts of the solid content of the pickled hydrous crumb, and the mixture was stirred at room temperature for 5 minutes in the coagulation tank, and then water was discharged from the coagulation tank to obtain the hydrous crumb. The water-containing crumb of acrylic rubber (A1) was obtained by washing with pure water.

[Example 1]
In Production Example 1, the extrusion type dryer 1 having the configuration shown in FIG. 1 and the conveyance type cooling device 5 shown in FIG. 2 which is directly connected to the discharge port of the dry rubber of the die 4 of the extrusion type dryer 1 are provided. The water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 was continuously dried and cooled. Specifically, the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 was dehydrated by using an expeller, and then the water-containing crumb after the dehydration treatment was processed by an extrusion mold having a structure shown in FIG. Dehydration and drying are performed by continuously supplying to the feed port 310 of the dryer 1, and the sheet-shaped dry rubber that is continuously extruded from the die 4 of the extrusion-type dryer 1 and discharged is shown in FIG. A sheet-shaped acrylic rubber was continuously manufactured by continuously cooling it in the transport cooling device 5 shown in FIG. As the conveyor cooling device 5 shown in FIG. 2, a conveyor 51 and a cooling means 52 having a length L1 of 40 m were used.

In Example 1, under the condition that the residence time in the transport cooling device 5 (that is, the time during which the dry rubber passes the distance L1 of the conveyor 51 and the cooling means 52 ) is 0.5 hours, Dehydration / drying by the extrusion dryer 1 and cooling of the transport cooling device 5 were performed. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 15 ° C.

  In Example 1, the temperature T1 of the dry rubber when discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and 40 from the time when the sheet-shaped dry rubber was discharged from the extrusion dryer 1. The time P1 required for the temperature to drop to 0 ° C is 0.45 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 267 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 27 ° C., and the thickness of the sheet-shaped dry rubber was 20 mm. The thickness of the sheet-shaped dry rubber was measured by the following method. That is, with respect to the sheet-shaped dry rubber, cutting is performed in such a manner that a cross section perpendicular to the longitudinal direction is exposed, and the operation of measuring the thickness of the thickest portion of the obtained cut surface with a caliper, The measurement was performed on five cut surfaces, and the average value of the obtained measurement results at five locations was calculated and used as the thickness of the sheet-shaped dry rubber (also in Examples 2 to 6 and Comparative Examples 1 to 4 described later). The same.).

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. Further, the Mooney viscosity (polymer Mooney) of acrylic rubber is 33, and the composition of acrylic rubber is as follows: ethyl acrylate unit 5% by weight, n-butyl acrylate unit 63% by weight, 2-methoxyethyl acrylate unit 30% by weight. The amount of the mono-n-butyl maleate unit was 2% by weight (the composition of the acrylic rubber was the same in Examples 2 to 5 and Comparative Examples 1 to 3 described later).

  Next, with respect to 100 parts of the sheet-shaped acrylic rubber obtained above, 60 parts of FEF carbon (trade name "Cast SO", manufactured by Tokai Carbon Co., Ltd.), 2 parts of stearic acid, higher fatty acid ester (trade name "Grec" G8205 ", manufactured by Dainippon Ink and Co., Ltd., and 1 part of 4,4'-bis (α, α-dimethylbenzyl) diphenylamine (trade name" Nocrac CD ", manufactured by Ouchi Shinko Chemical Co., Ltd.) were added. And mixed at 50 ° C. for 5 minutes. Then, the obtained mixture was transferred to a roll at 50 ° C., and 0.6 parts of hexamethylenediamine carbamate (trade name “Diak # 1”, an aliphatic polyvalent amine compound manufactured by DuPont Dow Elastomer), 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 Mooney viscosity (compound Mooney), Mooney scorch, and normal physical properties (tensile strength, elongation, 100% tensile stress, hardness) was measured. Table 1 shows the results.

[Example 2]
In Example 2 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Example 2, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 0.75 hours. Further, the temperature of the cooling air blown onto the sheet-shaped dry rubber from the cooling means 52 provided in the transport cooling device 5 was 21 ° C.

  In Example 2, the temperature T1 of the dried rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and the temperature of the sheet-shaped dried rubber was 40 at the time of being discharged from the extrusion dryer 1. The time P1 required to lower the temperature to 0 ° C is 0.66 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 182 ° C./hour. The temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 24 ° C., and the thickness of the sheet-shaped dry rubber was 22 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The Mooney viscosity (polymer Mooney) of the acrylic rubber was 32.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Example 3]
In Example 3, the same extrusion type dryer 1 and transport type cooling device 5 as in Example 1 were used, while a water cooling device (sheet) was used between the extrusion type dryer 1 and the transport type cooling device 5. In the manufacturing example 1 by interposing a device for cooling by continuously immersing the dry rubber in water in water, using the extrusion type dryer 1, the water cooling device and the transport cooling device 5. The water-containing crumb of the obtained acrylic rubber (A1) was continuously dried and cooled. In Example 3, dehydration / drying by the extrusion dryer 1 was performed under the condition that the residence time in the water cooling device was 0.1 hours and then the residence time in the transport cooling device 5 was 0.4 hours. , And the cooling by the water cooling device and the transport cooling device 5. The temperature of the water cooling device was kept at 20 ° C., and the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 22 ° C.

  In Example 3, the temperature T1 of the dry rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and the temperature of the sheet-shaped dry rubber was 40 at the time of being discharged from the extrusion dryer 1. The time P1 required to lower the temperature to 0 ° C is 0.35 hours, and the cooling is performed when the temperature of the dried rubber is cooled to 40 ° C from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 343 ° C./hour. The temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 21 ° C., and the thickness of the sheet-shaped dry rubber was 21 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber had a Mooney viscosity (polymer Mooney) of 35.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Example 4]
In Example 4 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Example 4, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 1.5 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 15 ° C.

  In Example 4, the temperature T1 of the dry rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and the temperature T1 of the sheet-shaped dry rubber was 40 at the time of being discharged from the extrusion dryer 1. The time P1 required for the temperature to drop to ℃ is 1.23 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C. from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 98 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 15 ° C., and the thickness of the sheet-shaped dry rubber was 25 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The Mooney viscosity (polymer Mooney) of the acrylic rubber was 34.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Example 5]
In Example 5 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Example 5, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 0.4 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 15 ° C.

  In Example 5, the temperature T1 of the dry rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and 40 from the time of discharging the sheet-shaped dry rubber from the extrusion dryer 1. The time P1 required to lower the temperature to 0 ° C is 0.38 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 316 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 35 ° C., and the thickness of the sheet-shaped dry rubber was 23 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber had a Mooney viscosity (polymer Mooney) of 33.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Comparative Example 1]
In Comparative Example 1 as well, the same extrusion-type dryer 1 and transport-type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Comparative Example 1, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 4 hours. The temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 33 ° C. In Comparative Example 1, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was higher than 40 ° C., so after discharging from the transport cooling device 5, the sheet-shaped dry rubber was allowed to stand still at room temperature (23 ° C.). Then, the temperature of the sheet-shaped dry rubber was lowered to 40 ° C. The time required for the temperature to drop to 40 ° C. after discharging from the transport cooling device 5 was 2.12 hours.

  In Comparative Example 1, the temperature T1 of the dry rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and the temperature T1 of the sheet-shaped dry rubber was 40 at the time of being discharged from the extrusion dryer 1. The time P1 required for the temperature to decrease to ℃ is 6.12 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C. from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 20 ° C./hour. The temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 65 ° C., and the thickness of the sheet-shaped dry rubber was 26 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber had a Mooney viscosity (polymer Mooney) of 33.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Comparative Example 2]
In Comparative Example 2 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Comparative Example 2, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 0.5 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 15 ° C. In Comparative Example 2 as well, since the temperature of the sheet-shaped dry rubber discharged from the transport-type cooling device 5 was higher than 40 ° C., the sheet-shaped dry rubber was discharged from the transport-type cooling device 5 and then left at room temperature (23 ° C.). Then, the temperature of the sheet-shaped dry rubber was lowered to 40 ° C. The time required for the temperature to drop to 40 ° C. after discharging from the transport cooling device 5 was 2.63 hours.

  In Comparative Example 2, the temperature T1 of the dry rubber when discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and 40 from the time when the sheet-shaped dry rubber was discharged from the extrusion dryer 1. The time P1 required to lower the temperature to ℃ is 3.13 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C. from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 38 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport-type cooling device 5 was 70 ° C., and the thickness of the sheet-shaped dry rubber was 24 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber had a Mooney viscosity (polymer Mooney) of 35.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Comparative Example 3]
In Comparative Example 3 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1. It was In Comparative Example 3, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 4.5 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport type cooling device 5 to the sheet-shaped dry rubber was 30 ° C.

  In Comparative Example 3, the temperature T1 of the dry rubber at the time of being discharged from the die 4 of the extrusion dryer 1 was 162 ° C., and the temperature T1 of the sheet-shaped dry rubber was 40 at the time of being discharged from the extrusion dryer 1. The time P1 required for the temperature to decrease to ℃ is 4.32 hours, and the cooling when the temperature of the dry rubber is cooled to 40 ° C. from the time when the dry rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 28 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 37 ° C., and the thickness of the sheet-shaped dry rubber was 27 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The Mooney viscosity (polymer Mooney) of the acrylic rubber was 34.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. Table 1 shows the results.

[Evaluation of Examples 1 to 5 and Comparative Examples 1 to 3]
As shown in Table 1, after the water-containing crumb of acrylic rubber was dried by the extrusion-type dryer 1, the dry rubber was extruded from the extrusion-type dryer 1 and discharged, and the temperature of the dry rubber was cooled to 40 ° C. The acrylic rubber obtained by cooling under the condition that the cooling rate V1 at the time of cooling is 40 ° C./hour or more is a scorch time when the compounding agent such as a cross-linking agent is blended to obtain an acrylic rubber composition. The t5 is long, the scorch during the processing is effectively suppressed, and the increase value of the Mooney viscosity (difference between the polymer Mooney viscosity and the compound Mooney viscosity) due to the addition of the compounding agent is small, whereby the processing stability is excellent. (Examples 1 to 5).
On the other hand, when cooling is performed under the condition that the cooling rate V1 is less than 40 ° C./hour, the scorch time t5 in the case of using the acrylic rubber composition is short, scorch tends to occur during processing, and further, the blending The increase in Mooney viscosity due to addition of the agent (difference between polymer Mooney viscosity and compound Mooney viscosity) was also large, resulting in poor processability (Comparative Examples 1 to 3).

[Production Example 2]
Production Example 1 except that the amount of ethyl acrylate used was changed from 5 parts to 48 parts, the amount of n-butyl acrylate used was changed from 63 parts to 50 parts, and that 2-methoxyethyl acrylate was not used. A hydrous crumb of acrylic rubber (A2) was obtained in the same manner as in.

[Example 6]
In Example 6, the same extrusion-type dryer 1 and transport cooling device 5 as in Example 1 were used, and instead of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1, it was obtained in Production Example 2. The water-containing crumb of the acrylic rubber (A2) was continuously dried and cooled. In Example 6, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 0.5 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport cooling device 5 to the sheet-shaped dry rubber was 15 ° C.

  In Example 6, the temperature T1 of the dry rubber when discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and 40 from the time when the sheet-shaped dry rubber was discharged from the extrusion dryer 1. The time P1 required to lower the temperature to 0 ° C is 0.46 hours, and the cooling is performed when the temperature of the dried rubber is cooled to 40 ° C from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 261 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 30 ° C., and the thickness of the sheet-shaped dry rubber was 26 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber has a Mooney viscosity (polymer Mooney) of 30, and the acrylic rubber has a composition of 48% by weight of ethyl acrylate unit, 50% by weight of n-butyl acrylate unit and 2% by weight of mono n-butyl maleate unit. (The composition of the acrylic rubber is the same as in Comparative Example 4 described later).

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. The results are shown in Table 2.

[Comparative Example 4]
In Comparative Example 4 as well, the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1 were used to continuously dry and cool the water-containing crumb of the acrylic rubber (A2) obtained in Production Example 2. It was In Comparative Example 4, dehydration / drying by the extrusion dryer 1 and cooling by the transport cooling device 5 were performed under the condition that the residence time in the transport cooling device 5 was 3.5 hours. Further, the temperature of the cooling air blown from the cooling means 52 provided in the transport type cooling device 5 to the sheet-shaped dry rubber was 30 ° C. In Comparative Example 4, the temperature of the sheet-shaped dry rubber discharged from the conveyance type cooling device 5 was higher than 40 ° C, and therefore, after being discharged from the conveyance type cooling device 5, the sheet-shaped dry rubber was allowed to stand still at room temperature (23 ° C). Then, the temperature of the sheet-shaped dry rubber was lowered to 40 ° C. The time required for the temperature to drop to 40 ° C. after being discharged from the transport cooling device 5 was 0.92 hours.

  In Comparative Example 4, the temperature T1 of the dry rubber when discharged from the die 4 of the extrusion dryer 1 was 160 ° C., and 40 from the time when the sheet-shaped dry rubber was discharged from the extrusion dryer 1. The time P1 required for the temperature to decrease to ℃ is 4.42 hours, and the cooling when the temperature of the dried rubber is cooled to 40 ° C. from the time when the dried rubber is extruded from the extrusion dryer 1 and discharged. The speed V1 was 27 ° C./hour. Further, the temperature of the sheet-shaped dry rubber discharged from the transport cooling device 5 was 64 ° C., and the thickness of the sheet-shaped dry rubber was 23 mm.

  The water content of the obtained sheet-shaped acrylic rubber was measured, and it was substantially free of water and was 0% by weight. The acrylic rubber had a Mooney viscosity (polymer Mooney) of 33.

  Next, an acrylic rubber composition was obtained in the same manner as in Example 1 except that the sheet-shaped acrylic rubber obtained above was used, and each measurement was performed in the same manner. The results are shown in Table 2.

[Evaluation of Example 6 and Comparative Example 4]
As shown in Table 2, when the acrylic rubber containing no (meth) acrylic acid alkoxyalkyl ester monomer unit is used, the dried rubber is similarly extruded from the extrusion dryer 1 and discharged. From the time when the temperature of the dried rubber is cooled to 40 ° C., the acrylic rubber composition is blended with a compounding agent such as a crosslinking agent by cooling under the condition that the cooling rate V1 is 40 ° C./hour or more. In such a case, the scorch time t5 was long, and the scorch during processing was effectively suppressed, resulting in excellent processing stability (Example 6, Comparative Example 4).

DESCRIPTION OF SYMBOLS 1 ... Extrusion type dryer 2 ... Drive unit 3 ... Barrel 4 ... Die 5 ... Conveying type cooling device
51 ... Conveyor
52 ... Cooling means

Claims (4)

A method for producing an acrylic rubber containing a (meth) acrylic acid alkoxyalkyl ester monomer unit ,
A step of drying the water-containing crumb of acrylic rubber with an extrusion-type dryer,
While extruding from the extrusion dryer as a sheet-shaped rubber having a thickness of 50 mm or less, a step of cooling the sheet-shaped dried rubber extruded from the extrusion-type dryer and discharged to 40 ° C. or less,
A method for producing an acrylic rubber, wherein, when cooling the dried rubber, the cooling rate after cooling from the extrusion dryer to 40 ° C. is 40 ° C./hour or more. Wherein when extruding the dried rubber from the extruder type dryer, 9 mm or more, the production method of the acrylic rubber according to output to claim 1 press from the extrusion drier as a sheet-like rubber of the following thickness 50 mm. Method for producing an acrylic rubber obtained by the production method according to claim 1 or 2, acrylic rubber composition comprising a step of mixing a crosslinking agent. A method for producing a rubber cross-linked product, comprising a step of crosslinking the acrylic rubber composition obtained by the production method according to claim 3 .

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