JP2019119772A - Process for producing acrylic rubber - Google Patents

Abstract

To provide an acrylic rubber in which the scorch during processing is effectively suppressed, and thereby having an excellent processing stability.SOLUTION: Provided is a process for producing acrylic rubber, comprising: a step of drying acrylic rubber hydrous crumb with an extrusion type dryer; and a step of cooling the dried rubber extruded and discharged from the extrusion type dryer down to 40°C or lower, in which when cooling the dry rubber, the cooling rate at the time of cooling down to 40°C after the discharge from the extrusion type dryer is set to 40°C/hour or higher.SELECTED DRAWING: None

Description

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

  Acrylic rubber is a polymer having an acrylic ester as a main component, and is generally known as a rubber excellent in heat resistance, oil resistance and ozone resistance, and is widely used in the fields related to automobiles and the like.

  Such an acrylic rubber is usually subjected to emulsion polymerization of a monomer mixture constituting the acrylic rubber, and is coagulated by adding a coagulant to the obtained emulsion polymerization solution, and the water-containing crumb obtained by the coagulation is dried. It is manufactured by doing. At this time, although drying of rubber such as acrylic rubber is performed by various methods, a drying method using an extrusion type drier is known from the viewpoint of productivity (for example, refer to Patent Document 1).

  On the other hand, when drying of acrylic rubber is carried out using an extrusion-type drier as in the technique described in Patent Document 1, it is said that scorch tends to occur when a crosslinking agent or the like is blended in the resulting acrylic rubber. There was a problem.

Patent No. 3665870 gazette

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

  As a result of intensive studies to achieve the above object, the inventors of the present invention dry a water-containing crumb of acrylic rubber with an extrusion dryer, and set the cooling rate at the time of cooling the dried rubber after drying to a predetermined range. It has been found that the above object can be achieved, and the present invention has been completed.

  That is, according to the present invention, there is provided a method of producing an acrylic rubber, comprising the steps of: drying a water-containing crumb of the acrylic rubber with an extrusion dryer; and drying the rubber extruded and discharged from the extrusion dryer. Cooling to 40 ° C. or less, wherein, when the drying rubber is cooled, an acrylic having a cooling rate of 40 ° C./hour or more when it is cooled to 40 ° C. after being discharged from the extrusion type drier A method of making rubber is provided.

In the manufacturing method of the present invention, when extruding the dry rubber from the extrusion type drier, it is extruded from the extrusion type drier as a sheet-like rubber having a thickness of 9 mm or more, and cooling of the dry rubber is performed in sheet form. Is preferred.
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, comprising the step of blending a crosslinking agent with the acrylic rubber obtained by any of the above-mentioned production methods.
Furthermore, according to the present invention, there is provided a method for producing a rubber cross-linked product, comprising the 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, thereby, the manufacturing method for manufacturing the acrylic rubber excellent in processing stability can be provided.

FIG. 1 is a view showing an example of an extrusion type drier used in the production method of the present invention. FIG. 2 is a view showing an example of a transfer 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 a main component (in the present invention, a component contained at 50% by weight or more in all monomer units constituting the acrylic rubber) in the molecule (in the present invention). (Meth) acrylic acid ester monomer [meaning of acrylic acid ester monomer and / or methacrylic acid ester monomer. Hereinafter, the same applies to methyl (meth) acrylate and the like. Rubber-like polymers containing units.

  The (meth) acrylic acid ester monomer that forms the (meth) acrylic acid ester monomer unit that is the main component of the acrylic rubber manufactured by the manufacturing method of the present invention is not particularly limited. And acrylic acid alkyl ester monomers, and (meth) acrylic acid alkoxy alkyl ester monomers, and the like.

  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. 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) Examples thereof include 2-ethylhexyl acrylate and cyclohexyl (meth) acrylate. Among these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and ethyl acrylate and n-butyl acrylate are particularly preferable. These can be used singly 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 And 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-methoxy acrylate is preferable. Ethyl is particularly preferred. These can be used singly or in combination of two or more.

  The content of (meth) acrylic acid ester monomer units in the acrylic rubber produced by the production method of the present invention is usually 50 to 99.9% by weight, preferably 60 to 99.5% by weight, Preferably, it is 70 to 99.5% by weight. If the content of the (meth) acrylic acid ester monomer unit is too small, the weather resistance, heat resistance and oil resistance of the resulting crosslinked rubber product may be reduced. There is a risk that the heat resistance of the object may decrease.

  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, ie, the improvement effect of scorch at the time of processing is greater. It is preferable to use one containing at least a (meth) acrylic acid alkoxyalkyl ester monomer unit, and the (meth) acrylic acid alkoxyalkyl ester monomer unit is preferably 1 to 50% by weight, more preferably 5 to 5% by weight. Those containing 45% by weight, particularly preferably 10 to 40% by weight, are preferred.

  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, and, for example, α, β-ethylenically unsaturated carboxylic acid monomer; monomer having an epoxy group; having a halogen atom Monomers; diene monomers; and the like.

  The α, β-ethylenically unsaturated carboxylic acid monomer which forms the α, β-ethylenically unsaturated carboxylic acid monomer unit is not particularly limited, and, for example, α, β-carbon atoms having 3 to 12 carbon atoms Ethylenically unsaturated monocarboxylic acid, C4-12 α, β-ethylenically unsaturated dicarboxylic acid, and C4-12 α, β-ethylenically unsaturated dicarboxylic acid and C1-8 alkanol And monoesters thereof. By using an α, β-ethylenically unsaturated carboxylic acid monomer, an acrylic rubber can be made into a carboxyl group-containing acrylic rubber having a carboxyl group as a crosslinking point, whereby a rubber crosslinked product can be obtained. And compression set resistance can be further enhanced.

Specific examples of the C 3-12 α, β-ethylenically unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, α-ethyl acrylic acid, crotonic acid, and cinnamic acid.
Specific examples of the α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms include butenedioic acid such as fumaric acid and maleic acid; itaconic acid; citraconic acid; chloromaleic acid;
Specific examples of monoesters of an α, β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkanol having 1 to 8 carbon atoms include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, and maleic acid Monocyclic alkyl esters of butenedioic acid such as monomethyl methacrylate, monoethyl maleate, mono n-butyl maleate, monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, maleate Butenedioic acid monoesters having an alicyclic structure such as acid monocyclohexenyl; monobasic itaconic acids such as monomethyl itaconate, monoethyl itaconate, mono n-butyl itaconate, monocyclohexyl itaconate and the like.
Among these, monoesters of C4-12 α, β-ethylenically unsaturated dicarboxylic acids and C1-8 alkanols are preferable, and butenedioic acid mono-chain alkyl esters, or butenediones having an alicyclic structure Acid monoesters are more preferred, mono n-butyl fumarate, mono n-butyl maleate, monocyclohexyl fumarate, and monocyclohexyl maleate are even more preferred, and mono n-butyl maleate is particularly preferred. These α, β-ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. Among the above monomers, dicarboxylic acids also include those present as anhydrides.

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

  The monomer having a halogen atom is not particularly limited. For example, unsaturated alcohol ester of halogen-containing saturated carboxylic acid, (meth) acrylic acid haloalkyl ester, (meth) acrylic acid haloacyloxy alkyl ester, (meth) acrylic 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 the unsaturated alcohol ester of the halogen-containing saturated carboxylic acid include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate.
Specific examples of (meth) acrylic acid haloalkyl ester include chloromethyl (meth) acrylic acid, 1-chloroethyl (meth) acrylic acid, 2-chloroethyl (meth) acrylic acid, 1,2-dichloroethyl (meth) acrylic acid And 2-chloropropyl (meth) acrylate, 3-chloropropyl (meth) acrylate, and 2,3-dichloropropyl (meth) acrylate.
Specific examples of (meth) acrylic acid haloacyloxy alkyl ester include (meth) acrylic acid 2- (chloroacetoxy) ethyl, (meth) acrylic acid 2- (chloroacetoxy) propyl, (meth) acrylic acid 3- (chloro) Examples include acetoxy) propyl and 3- (hydroxychloroacetoxy) propyl (meth) acrylate.
Specific examples of (meth) acrylic acid (haloacetylcarbamoyloxy) alkyl ester include 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate and 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate Can be 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.

As a specific example of the halogen-containing unsaturated amide, N-chloromethyl (meth) acrylamide and the like can be mentioned.
Specific examples of the haloacetyl group-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether, p-vinylbenzyl chloroacetic acid ester and the like.

As a diene monomer, a conjugated diene monomer and a nonconjugated diene monomer are mentioned.
As specific examples of the conjugated diene monomer, 1,3-butadiene, isoprene, piperylene and the like can be mentioned.
Specific examples of the non-conjugated diene monomer include ethylidene norbornene, dicyclopentadiene, dicyclopentadienyl (meth) acrylate, and 2-dicyclopentadienylethyl (meth) acrylate. .

  When an α, β-ethylenically unsaturated carboxylic acid monomer is used among the crosslinkable monomers, the acrylic rubber can be made into a carboxyl group-containing acrylic rubber. By setting the acrylic rubber to a carboxyl group-containing acrylic rubber, the compression set resistance can be improved while improving 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, still more preferably 0. 0.5 to 5% by weight. By setting the content of the crosslinkable monomer unit in the above-mentioned range, the compression set resistance can be more appropriately enhanced while making the mechanical properties and the heat resistance of the obtained rubber crosslinked product favorable.

  The acrylic rubber produced by the production method of the present invention is not limited to (meth) acrylic acid ester monomer units and, if necessary, crosslinkable monomer units, other monomers copolymerizable therewith. It may have a unit of mer. As such other copolymerizable monomers, aromatic vinyl monomers, α, β-ethylenically unsaturated nitrile monomers, acrylamide monomers, other olefin monomers, etc. It 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.
Acrylamide, methacrylamide, etc. are mentioned as an acrylamide type monomer.
Other olefin 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 units of these other copolymerizable monomers 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.

<Production method of acrylic rubber>
Then, the manufacturing method of the acrylic rubber of this invention is demonstrated.
The method for producing acrylic rubber of the present invention is
Drying the water-containing crumb of acrylic rubber with an extrusion type dryer;
Cooling the dried rubber extruded and discharged from the extrusion dryer to 40 ° C. or lower,
When the dry rubber is cooled, the cooling rate at the time of cooling to 40 ° C. after discharging from the extrusion type drier is 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 the acrylic rubber, and the obtained emulsion polymerization A coagulant is added to the liquid, and it can manufacture by passing through the coagulation | solidification process which obtains the water-containing crumb of acrylic rubber.

  As an 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 usual method.

  The emulsifier is not particularly limited, and polyoxyethylene alkyl ether such as polyoxyethylene dodecyl ether, polyoxyethylene alkyl phenol ether such as polyoxyethylene nonyl phenyl ether, polyoxyethylene alkyl ester such as polyoxyethylene stearic acid ester, Nonionic emulsifiers such as polyoxyethylene sorbitan alkyl ester and polyoxyethylene polyoxypropylene copolymer; salts of fatty acids such as myristic acid, palmitic acid, oleic acid, linolenic acid, alkyl benzene sulfonates such as sodium dodecyl benzene sulfonate , Higher alcohol sulfuric acid ester salts such as sodium lauryl sulfate, higher phosphoric acid ester salts such as sodium alkyl phosphoric acid 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. Among these nonionic emulsifiers, polyoxyethylene polypropylene glycol, polyethylene glycol monostearate, polyoxyethylene alkyl ether, and polyoxyethylene alkyl phenol ether are preferable. In addition, as a nonionic emulsifier, that whose weight average molecular weight is less than 10,000 is preferable, the one whose weight average molecular weight is 500 to 8000 is more preferable, and its weight average molecular weight is more preferably 600 to 5,000. Among these anionic emulsifiers, higher phosphoric acid ester salts and higher alcohol sulfuric acid ester salts are preferred.

  Among these emulsifiers, nonionic emulsifiers and anionic emulsifiers are preferable, and it is preferable to use the nonionic emulsifier and the anionic emulsifier in combination. By combining and using a nonionic emulsifier and an anionic emulsifier, it is used in the coagulation step to be described later while effectively suppressing the occurrence of stains due to the adhesion of a polymer to a polymerization apparatus (for example, a polymerization tank) at the time of emulsion polymerization. The amount of coagulant used can be reduced, and as a result, the amount of coagulant in the finally obtained acrylic rubber can be reduced, whereby the water resistance of the obtained acrylic rubber can be increased. .

  In addition, since the emulsifying action can be enhanced by using the nonionic emulsifier and the anionic emulsifier in combination, the amount of the emulsifier itself can be reduced, and as a result, in the finally obtained acrylic rubber. The residual amount of the emulsifier contained in can be reduced, whereby the water resistance of the resulting acrylic rubber can be increased.

  The amount of the emulsifier used is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and still more preferably 1 to 3 parts by weight, based on 100 parts by weight of the monomers used for polymerization. It is a weight part. 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 and 4 parts by weight or less, preferably 0 based on 100 parts by weight of the monomer used for polymerization. 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 polymerization The amount is more than 0 parts by weight and 4 parts by weight or less, preferably 0.1 to 3 parts by weight, more preferably 0.5 to 2 parts by weight, and still more preferably 0.35 to 0.75 parts by weight. In addition, when the nonionic emulsifier and the anionic emulsifier are used in combination, the weight ratio of the nonionic emulsifier / the anionic emulsifier is preferably 1/99 to 99/1, and 10/90 to 80/20. More preferably, 25/75 to 75/25 is more preferable, 50/50 to 75/25 is even more preferable, and 65/35 to 75 from the viewpoint of more appropriately preventing the occurrence of fouling of the polymerization apparatus during polymerization. / 25 is particularly preferred.

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

  Moreover, it is preferable to use the organic peroxide and the inorganic peroxide as a polymerization initiator as a redox type polymerization initiator in combination with a reducing agent. The reducing agent to be used in combination is not particularly limited, but compounds containing metal ions in a reduced state such as ferrous sulfate, sodium ferric hexamethylenediamine tetraacetate, cuprous naphthenate, etc .; ascorbic acid, ascorbic acid sodium salt Ascorbic acid (salts) such as potassium ascorbate; erythorbic acid (salts) such as erythorbic acid, sodium erythorbate, potassium erythorbate; saccharides; sulfinates such as sodium hydroxymethanesulfinate; sodium sulfite, potassium sulfite, sulfite Sodium hydrogen aldehyde, sodium aldehyde bisulfite, sulfite of potassium bisulfite; sodium pyrosulfite such as sodium pyrosulfite, potassium metabisulfite, sodium pyrobisulfite, potassium metabisulfite, etc. sodium thiosulfate Thiosulfates such as potassium thiosulfate; phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium phosphite sodium phosphate (salt); pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, Pyrophosphorous acid (salts) such as sodium hydrogen pyrophosphite and potassium hydrogen pyrophosphite; sodium formaldehyde sulfoxylate and the like. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent used is preferably 0.0003 to 0.5 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

  Examples of the polymerization terminator include hydroxylamine, hydroxylamine sulfate, diethylhydroxylamine, hydroxylamine sulfonic acid and alkali metal salts thereof, sodium dimethyldithiocarbamate, hydroquinone and the like. Although the usage-amount of a polymerization terminator is not specifically limited, Preferably it is 0.1-2 weight part with respect to 100 weight part of monomers used for superposition | polymerization.

  The amount of water used is preferably 80 to 500 parts by weight, more preferably 100 to 300 parts by weight, with respect to 100 parts by weight of the monomer used for polymerization.

  In the case of emulsion polymerization, if necessary, a polymerization auxiliary material such as a molecular weight modifier, a particle size modifier, a chelating agent, an oxygen scavenger and the like can be used.

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

  When the polymerization reaction is carried out while continuously dropping the monomer used for polymerization, the monomer used for polymerization is mixed with an emulsifier and water to form a monomer emulsion, and the monomer It is preferable to drip continuously in the state of an emulsion. The preparation method of the monomer emulsion is not particularly limited, and a method of stirring the total amount of monomers used for polymerization, the total amount of emulsifier and water with a stirrer such as a homomixer or a disk turbine, etc. It can be mentioned. The amount of water used in the monomer emulsion is preferably 10 to 70 parts by weight, more preferably 20 to 50 parts by weight, with respect to 100 parts by weight of the monomer used for polymerization.

  In addition, with respect to all of the monomers used for polymerization, the polymerization initiator, and the reducing agent, when performing the polymerization reaction while continuously dropping into the polymerization reaction system from the start of the polymerization reaction to an arbitrary time, these are different May be dropped into the polymerization system using the dropping device of the above, or at least the polymerization initiator and the reducing agent are mixed in advance, and dropped into the polymerization system from the same dropping device as an aqueous solution state if necessary. May be After completion of the dropwise addition, the reaction may be continued for an arbitrary time to further improve the polymerization reaction rate.

  Subsequently, a water-containing crumb of acrylic rubber can be obtained by adding a coagulant to the emulsion polymerization liquid obtained by the above-mentioned emulsion polymerization process.

  Although it does not specifically limit as a coagulant, For example, a 1-3 valence metal salt is mentioned. The monovalent to trivalent metal salt is a salt containing a metal that forms a monovalent to trivalent metal ion when dissolved in water, and is not particularly limited. For example, an inorganic acid selected from hydrochloric acid, nitric acid and sulfuric acid And salts of organic acids such as acetic acid and metals selected from sodium, potassium, lithium, magnesium, calcium, zinc, titanium, manganese, iron, cobalt, nickel, aluminum, tin and the like. In addition, 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, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, chloride Metal chlorides such as tin; sodium nitrate, potassium nitrate, lithium nitrate, magnesium nitrate, calcium nitrate, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, iron nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate, tin nitrate etc .; sodium sulfate And potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, sulfates such as tin sulfate, 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 preferably calcium chloride, sodium chloride, magnesium sulfate, sodium sulfate, and magnesium sulfate is more preferable from the viewpoint that scorch can be more appropriately prevented. , Sodium sulfate. Moreover, these can be used individually by 1 type or in combination of multiple types.

  The amount of the coagulant used can reduce the residual amount of the coagulant in the finally obtained acrylic rubber while making the coagulation of the acrylic rubber sufficient, whereby a crosslinked product of rubber is obtained, From the viewpoint of improving the compression set resistance and water resistance, 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 coagulation temperature is not particularly limited, but is preferably 50 to 90 ° C, more preferably 60 to 90 ° C, and still more preferably 78 to 90 ° C.

  Further, in the present invention, in the emulsion polymerization solution before adding and coagulating the coagulant, a part of the compounding agents among the compounding agents to be compounded to the acrylic rubber, specifically, an antiaging agent, a lubricant and an ethylene oxide based agent At least one of the polymers is preferably contained in advance. That is, it is preferable to coagulate at least one of the anti-aging agent, the lubricant and the ethylene oxide polymer in a state of being already blended in the emulsion polymerization solution, and to blend the emulsion polymerization solution in which these are blended.

  For example, when an antiaging agent is contained in advance in the emulsion polymerization liquid before coagulation, the antiaging agent can be blended in the state of the emulsion polymerization liquid before coagulation, and therefore, in the acrylic rubber The anti-aging agent can be appropriately dispersed, and even when the blending amount of the anti-aging agent is reduced, the addition effect can be sufficiently exhibited. Specifically, the compounding amount of the antioxidant is preferably 0.1 to 2 parts by weight, more preferably 0.2 to 1.2 parts by weight with respect to 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. Even if the blending amount is relatively small, the addition effect can be sufficiently exhibited. Even when an antiaging agent is added to the emulsion polymerization solution before coagulation, the added antiaging agent is not substantially removed in the subsequent coagulation, washing, drying, etc. And its addition effect can be sufficiently exhibited. Further, as a method of incorporating an anti-aging agent into the emulsion polymerization solution, a method of adding it to the emulsion polymerization solution after emulsion polymerization and before coagulation, or a method of adding it to the solution before emulsion polymerization is carried out However, if it is added to the solution prior to the emulsion polymerization, there is a risk that contamination of the polymerization apparatus and the like may occur. The method of addition is preferred.

  The anti-aging agent is not particularly limited, but it is a phenol-based anti-aging agent containing no sulfur atom; thiophenol-based anti-aging agent; phosphorous ester based anti-aging agent; sulfur ester-based anti-aging agent; amine based anti-aging agent An imidazole anti-aging agent; quinoline type anti-aging agent; hydroquinone anti-aging agent; One of these anti-aging agents may be used alone, or two or more thereof may be used in combination.

  Further, by previously containing the lubricant in the emulsion polymerization liquid before coagulation, the obtained acrylic rubber can be contained in a state in which the lubricant is well dispersed, and as a result, the obtained acrylic rubber Can be appropriately reduced, whereby the roll processability can be made better. 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, still more preferably 0 with respect to 100 parts by weight of the acrylic rubber component in the emulsion polymerization solution. 0.2 to 0.3 parts by weight. In addition, even when the lubricant is contained in the emulsion polymerization solution before coagulation, the lubricant previously incorporated in the subsequent coagulation, washing, drying, etc. is not substantially removed, and therefore, in the emulsion polymerization solution. Even when it is contained, it can fully exhibit its addition effect.

  The lubricant is not particularly limited, and examples include phosphoric acid esters, fatty acid esters, fatty acid amides, higher fatty acids, and the like. Further, as a method of incorporating a lubricant into the emulsion polymerization solution, a method of adding to the emulsion polymerization solution after emulsion polymerization and before coagulation and a method of adding to a solution before emulsion polymerization are mentioned. Be

  Furthermore, the coagulation property of the emulsion polymerization liquid can be improved by previously containing the ethylene oxide polymer in the emulsion polymerization liquid before coagulation, thereby reducing the amount of coagulant in the coagulation step. As a result, the residual amount in the finally obtained acrylic rubber can be reduced, and the water resistance can be improved in the case of using a rubber crosslinked product. The ethylene oxide polymer is not particularly limited as long as it is a polymer having a polyethylene oxide structure as a main chain structure, and polyethylene oxide, polypropylene oxide, ethylene oxide / propylene oxide copolymer, etc. may be mentioned, among which poly Ethylene oxide is preferred. The compounding amount of the ethylene oxide polymer is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.6 parts by weight, still more preferably 100 parts by weight of the acrylic rubber component in the emulsion polymerization liquid. It is 0.02 to 0.5 parts by weight. The weight average molecular weight of the ethylene oxide polymer is preferably 10,000 to 1,000,000, more preferably 10,000 to 200,000, and still more preferably 20,000 to 120,000. Further, as a method of incorporating the ethylene oxide polymer in the emulsion polymerization solution, it is added to the emulsion polymerization solution after the emulsion polymerization and before coagulation, or added to the solution before the emulsion polymerization. The method is mentioned.

  In addition, the addition order in the case where an antiaging agent, a lubricant, and an ethylene oxide polymer are previously contained in the emulsion polymerization liquid before coagulation is not particularly limited, and may be appropriately selected.

  And, even when these anti-aging agents, lubricants and / or ethylene oxide polymers are previously contained in the emulsion polymerization solution before coagulation, the coagulant is added to the emulsion polymerization solution under the same conditions as above. By carrying out the coagulation operation, a water-containing crumb can be obtained.

  Moreover, you may wash as needed with respect to the water-containing crumb of the acrylic rubber obtained by passing through a coagulation | solidification process.

  Although it does not specifically limit as a washing | cleaning method, Water is used as a washing | cleaning liquid, The method of performing water washing by mixing the added water with a water-containing crumb is mentioned. The temperature at the time of water 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.

  In addition, the amount of water added to the water-containing crumb during washing with water is not particularly limited, but from the viewpoint of effectively reducing the residual amount of coagulant in the acrylic rubber finally obtained. The amount of water per wash is preferably 50 to 9,800 parts by weight, more preferably 300 to 1,800 parts by weight per 100 parts by weight of the solid content (mainly acrylic rubber component) contained in the water-containing crumb. It is a weight part.

  The number of times of water washing is not particularly limited, and may be once, but 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. It is time. From the viewpoint of reducing the residual amount of coagulant in the acrylic rubber finally obtained, it is preferable that the number of times of water washing is large, but even if the washing is carried out beyond the above range, the effect of removing the coagulant is Since the influence of the decrease in productivity is increased due to an increase in the number of processes while the size is small, the number of times of water washing is preferably in the above range.

  In addition, after washing with water, acid washing may be performed using an acid as the washing solution. By carrying out the acid washing, the compression set resistance in the case of forming a rubber crosslinked product can be further enhanced, and when the acrylic rubber is a carboxyl group-containing acrylic rubber having a carboxyl group, this acid washing is carried out. 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 and the like can be used without limitation. When acid is added to the water-containing crumb in acid washing, it is preferably added in the form of an aqueous solution, preferably pH = 6 or less, more preferably pH = 4 or less, and still more preferably pH = 3 or less. It is preferable to add in the state of aqueous solution. Further, the method of acid washing is not particularly limited, and for example, a method of mixing an aqueous solution of the added acid with a water-containing crumb can be mentioned.

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

  After acid washing, it is preferable to further wash with water, and the conditions for water washing may be the same as the conditions described above.

  Then, in the production method of the present invention, the water-containing crumb of acrylic rubber thus obtained is dried by an extrusion type drier, and then the dried rubber extruded from the extrusion type drier and discharged is Acrylic rubber (solid acrylic rubber) is obtained by cooling to a temperature not higher than ° C.

  The extrusion-type drier used for drying the water-containing crumb of acrylic rubber is not particularly limited, but it is possible if it is an extruder capable of dewatering and drying by kneading, whereby water-containing crumb can be dehydrated and dried. Although not particularly limited, for example, a single- or twin-screw extruder can be used, and it is preferable to use a two-screw extruder from the viewpoint of drying efficiency.

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

  The extrusion type drier 1 shown in FIG. 1 is a twin-screw extruder provided with a pair of screws (not shown) inside the barrel 3. The barrel 3 of the extrusion type dryer 1 is composed of a drive unit 2 and 15 barrel blocks 31 to 45 divided as shown in FIG. The drying zone 102 and the drying zone 104 are formed sequentially from the upstream side to the downstream side of the barrel 3.

  The supply zone 100 is an area for supplying the slurry containing the water-containing crumb to the inside of the barrel 3. The dewatering zone 102 is an area for separating and discharging a liquid (serum water) containing a coagulant and the like from the slurry containing the water-containing crumb. The drying zone 104 is an area where the dewatered crumb is dried.

  In the extrusion type drier 1, the inside of the barrel blocks 31, 32 corresponds to the feeding zone 100, the inside of the barrel blocks 33 to 37 corresponds to the dehydration zone 102, and the inside of the barrel blocks 38 to 45 corresponds to the drying zone 104 Do. In addition, the installation number of each barrel block is not specifically limited to the aspect shown in FIG. 1, According to the water-containing crumb of the acrylic rubber used as the object of drying, it can be made a suitable number.

  The barrel block 31 constituting the feed zone 100 is formed with a feed port 310 for receiving a water-containing crumb. In the barrel blocks 34 and 37 constituting the dehydration zone 102, discharge slits 340 and 370 for draining the water contained in the water-containing crumb are formed. In the barrel blocks 39, 41, 43, 45 constituting the drying zone 104, vent ports 390, 410, 430, 450 for degassing are respectively formed.

  Inside the barrel 3, a pair of screws are arranged. At the proximal end of the pair of screws, drive means such as a motor stored in the drive unit 2 are connected to drive the same, whereby the pair of screws are rotatably held. As a pair of screws, it is preferable that it is a biaxial meshing type | mold in which the peak part and the valley part were made to mutually mesh | engagement, dewatering of a water-containing crumb and drying efficiency can be improved by this. The rotation direction of the pair of screws may be the same or different, but in terms of the performance of the self-cleaning, it is preferable to rotate in the same direction. It does not specifically limit as a screw shape of a pair of screw, What is necessary is just to make it the shape required for each zone in each zone of supply zone 100, dehydration zone 102, and drying zone 104, and is not limited in particular.

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

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

  The water-containing crumb introduced into the feeding zone 100 is fed to the dewatering 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 dewatered in the dewatering zone 102 is sent to the drying zone 104 by the rotation of a screw. The crumbs sent to the drying zone 104 are plasticized and kneaded by the rotation of a screw to form a melt, and are transported downstream while generating heat and raising the temperature. Then, when the melt reaches vent ports 390, 410, 430, 450 provided in barrel blocks 39, 41, 43, 45, the pressure is released, so the water contained in the melt is separated and vaporized. Be done. The separated and vaporized water (vapor) 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. In addition, the internal pressure is about 1000 to 5000 kPa.

  By passing through the drying zone 104, the dried crumb is delivered by the screw to the outlet side and introduced into the die 4, where it is extruded as a sheet-like dry rubber and discharged from the extrusion dryer 1 . At this time, the moisture content of the dried rubber is preferably 1% by weight or less, more preferably 0.7% by weight or less, and still more preferably 0.5% by weight or less. The thickness of the sheet-like dry rubber discharged from the extrusion dryer 1 is not particularly limited, but from the viewpoint of suppressing the decrease in productivity due to the decrease in drying speed due to the thickness being too thin, and The thickness is preferably 9 mm or more, more preferably 13 mm or more, and still more preferably from the viewpoint of reducing the load on the extrusion-type drier 1 due to an increase in pressure loss to reduce the thickness. It is 15 mm or more. The upper limit of the thickness of the sheet-like 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 later. Is 35 mm or less.

  Next, in the production method of the present invention, an acrylic rubber (solid acrylic rubber) is obtained by cooling the dried rubber extruded by an extrusion dryer such as the extrusion dryer 1 shown in FIG. Get). In the production method of the present invention, the cooling rate at the time of 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 the same time is 40.degree. C./hour or more. According to the production method of the present invention, the cooling rate at which the temperature of the dry rubber is cooled to 40 ° C. is 40 ° C./hour or more after the dry rubber is extruded from the extrusion dryer and discharged. Thereby, the scorch at the time of processing can be effectively suppressed, and the acrylic rubber thus obtained can be made excellent in processing stability.

In the production method of the present invention, when the temperature of the dry rubber is cooled to 40 ° C. from the point of time when the dry rubber is extruded from the extrusion type dryer and discharged, the cooling rate is V1. The velocity V1 (unit: ° C./hour) is the temperature T1 (unit: ° C.) of the dry rubber at the time of discharge from the extrusion dryer and the temperature of the dry rubber from the time of discharge from the extrusion dryer It can be determined according to the following formula (1) from the time P1 (unit: hour) required to lower to 40 ° C.
Cooling rate V1 (° C./hour)={temperature T1-40 at the time of extrusion from the extrusion-type drier} / time required to decrease to 40 ° C. P1 (1)
For example, the temperature T1 at the time of extrusion from the extrusion dryer is 160 ° C., and the time taken for the temperature to drop to 40 ° C. after the drying rubber is discharged from the extrusion dryer is 0.5 hours In this case, the cooling rate V1 is 240.degree. 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, calculation is performed from the temperature T1 and the time P1. The cooling may be performed under conditions such that the cooling rate to be performed is 40.degree. C./hour or more. For example, the temperature gradient when decreasing from the temperature T1 to 40.degree. C. does not have to be constant. For example, the temperature gradient due to cooling may be relatively large at the initial stage of cooling while the temperature gradient due to cooling may be relatively small at the later stage of cooling.

  In the production method of the present invention, the cooling rate V1 when the temperature of the dry rubber is cooled to 40 ° C. becomes 40 ° C./hour or more from the time when the dry rubber is extruded from the extrusion type dryer and discharged. 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. It is less than / hour.

  Further, in the production method of the present invention, the method for cooling the dried rubber extruded and discharged from the extrusion type drier is not particularly limited. For example, a method of blowing cooling air onto the dried rubber for cooling The method of water-cooling, such as a method of spraying water on dry rubber and a method of immersing dry rubber in water, may be mentioned. In addition, these may be used in combination, and as an example, a method of blowing cooling air after cooling by water cooling may be adopted. In the method of blowing cooling air, the temperature of the cooling air used for cooling may be less than room temperature (23 ° C.), but is preferably 1 to 22 ° C., more preferably 5 to 22 ° C. In the method by water cooling, the temperature of water used for cooling is preferably 1 to 22 ° C, more preferably 5 to 21 ° C. When the method of blowing cooling air or the method of blowing water is adopted when cooling is performed, the amount of spraying (output at the time of spraying) is not particularly limited, and the thickness of dry rubber and the target cooling It may be set appropriately according to the speed V1. Of the method of blowing cooling air and cooling, and the method of water cooling, the method of blowing cooling and cooling is preferable from the viewpoint that the amount of water in the resulting dried rubber can be more appropriately reduced.

  Further, in the production method of the present invention, it is required when the temperature of the dried rubber is lowered to 40 ° C. from the point of time when the dried rubber is discharged from the extrusion dryer, when cooling the dried rubber extruded and discharged from the extrusion dryer. The time P1 is preferably 2.5 hours or less, more preferably 1.5 hours or less, and still more preferably 1 hour or less, from the viewpoint of production efficiency.

  In the production method of the present invention, the method for cooling the dried rubber extruded and discharged from the extrusion dryer is not particularly limited, and the dried rubber is extruded from the extrusion dryer and discharged A method may be adopted such that the cooling rate V1 when the temperature of the dry rubber is cooled to 40 ° C. is 40 ° C./hour or more, but, for example, the concrete in the case of performing cooling by a method of blowing cooling air. As an example of the aspect, the method of using the conveyance type cooling device 5 as shown in FIG. 2 is mentioned.

  The conveyance type cooling device 5 shown in FIG. 2 is installed, for example, in a state directly connected to the dry rubber discharge port of the die 4 of the extrusion type dryer 1 shown in FIG. A conveying type cooling device, which conveys the sheet-like dry rubber discharged from the die 4 of the extrusion type dryer 1 in the direction of the arrow in FIG. It is an apparatus which can perform cooling of dry rubber by blowing a cooling air from 7. The cooling means 7 is not particularly limited, but, for example, cooling air sent from cooling air generation means (not shown) can be supplied to the drying rubber on the conveyor 6 from a plurality of cooling ports provided on the conveyor 6 side. And the like.

  In addition, a cutting mechanism (not shown) is attached to the downstream side of the conveyance type cooling device 5 shown in FIG. 2 and a predetermined size is obtained by cutting the cooled sheet-like dry rubber at a predetermined interval. Acrylic rubber sheet.

  The conveyor 6 of the transport type cooling device 5 and the length of the cooling means 7 (the length of the portion to which the 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, the transport speed of the dry rubber in the transport type cooling device 5 is the length L1 of the conveyor 6 and the cooling means 7, the discharge speed of the dry rubber discharged from the extrusion type dryer, the target cooling speed V1, and the time Although it may adjust suitably according to P1, it is 10-100 m / hour, for example, More preferably, it is 15-70 m / hour. The conveyance type cooling device 5 is not particularly limited to the configuration provided with one conveyor 6 and one cooling means 7 as shown in FIG. 2, and two or more conveyors 6 and corresponding two or more coolings It is good also as composition provided with the means 7. In this case, the lengths of two or more cooling means 7 may be in the above range.

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

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

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

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

  The crosslinking agent is not particularly limited, and examples thereof include polyhydric amine compounds such as diamine compounds, and carbonates thereof; sulfur; sulfur donors; triazine thiol compounds; polyvalent epoxy compounds; organic carboxylic acid ammonium salts; Well-known crosslinking agents such as oxides; metal salts of dithiocarbamates; polyvalent carboxylic acids; quaternary onium salts; imidazole compounds; isocyanuric acid compounds; organic peroxides; These crosslinking agents can be used singly or in combination of two or more. It is preferable to select suitably as a crosslinking agent according to the kind of crosslinkable monomer unit.

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

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

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

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

  The content of the crosslinking agent in the acrylic rubber composition of the present invention is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, particularly preferably 0. 2 to 4 parts by weight. By making content of a crosslinking agent into the said range, mechanical strength as a rubber crosslinked material can be made into outstanding thing, making rubber elasticity sufficient.

  The acrylic rubber composition of the present invention preferably further contains a crosslinking accelerator. The crosslinking accelerator is not particularly limited, but the acrylic rubber produced by the production method of the present invention is one having a carboxyl group as a crosslinkable group, and the crosslinking agent is a polyvalent amine compound or its carbonic acid. When it is a salt, it is a guanidine compound, a diazabicycloalkene compound, an imidazole compound, a quaternary onium salt, a tertiary phosphine compound, an aliphatic monovalent secondary amine compound, 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 singly or in combination of two or more.

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

  The aliphatic monovalent secondary amine compound is a compound in which two of hydrogen atoms of ammonia are substituted with aliphatic hydrocarbon groups. The aliphatic hydrocarbon group substituted with a hydrogen atom is preferably one having 1 to 30 carbon atoms. Specific examples of aliphatic monovalent secondary amine compounds 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, dicetaylamine, di-2-ethylhexylamine, dioctadecylamine and the like.

  The aliphatic monovalent tertiary amine compound is a compound in which all three hydrogen atoms of ammonia are substituted with aliphatic hydrocarbon groups. The aliphatic hydrocarbon group substituted with a hydrogen atom is preferably one having 1 to 30 carbon atoms. Specific examples of aliphatic monovalent tertiary amine compounds include trimethylamine, triethylamine, tripropylamine, triarylamine, triisopropylamine, tri-n-butylamine, tri-t-butylamine, tri-sec-butylamine and trihexylamine And triheptylamine, trioctylamine, torinylamine, tridecylamine, triundecylamine, and tridodecylamine.

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

  Moreover, the acrylic rubber composition of this invention can mix | blend the compounding agent normally used in the rubber processing field other than said each component. Such additives include, for example, reinforcing fillers such as silica and carbon black; non-reinforcing fillers such as calcium carbonate and clay; anti-aging agents; light stabilizers; scorch inhibitors; plasticizers; Adhesives, lubricants, lubricants, flame retardants, mildew proofing agents, antistatic agents, coloring agents, crosslinking retarders, and the like. The compounding amount of these compounding agents is not particularly limited as long as the objects and effects of the present invention are not impaired, and an amount according to the object of the compounding can be appropriately compounded.

  Furthermore, rubbers, elastomers, resins and the like other than the above-mentioned acrylic rubber of the present invention may be further blended into the acrylic rubber composition of the present invention as long as the effects of the present invention are not impaired. For example, rubbers other than acrylic rubber other than acrylic rubber of the present invention described above, such as natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, fluororubber, etc .; Elastomers, elastomers such as styrene elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, polysiloxane elastomers, etc .; polyolefin resins, polystyrene resins, polyacrylic resins, polyphenylene ether resins, polyesters Resins, such as system resin, a polycarbonate-type resin, a polyamide resin, a vinyl chloride resin, a fluorine resin, etc. can be mix | blended. The total blending 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, more preferably 100 parts by weight of acrylic rubber. It is 1 part by weight or less.

  In the acrylic rubber composition of the present invention, a crosslinking agent and various other compounding agents used as needed are compounded into acrylic rubber, mixed and kneaded with a Banbury mixer or a kneader, and then using a kneading roll. It is further prepared by kneading and the like.

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

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

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

  And, the rubber cross-linked product of the present invention thus obtained is, for example, a sealing material such as an O-ring, packing, oil seal, bearing seal, etc. in a wide range of fields such as transport machines such as automobiles, general equipments, electrical equipments Gasket; shock absorbing material, anti-vibration material, electric wire coating material, industrial belts, tubes, hoses, sheets, etc.

Hereinafter, the present invention will be more specifically described by way of examples and comparative examples. In addition, unless otherwise indicated, "part" in each case is a basis of weight.
Various physical properties were evaluated according to the following method.

[Mooney viscosity (ML 1 + 4, 100 ° C.)]
The Mooney viscosity (polymer Mooney) of acrylic rubber and the Mooney viscosity (compound Mooney) of acrylic rubber composition were measured according to JIS K6300.

[Water content of acrylic rubber after drying and cooling]
The moisture content (heat loss) of the acrylic rubber after drying and cooling was determined according to the "oven method" defined in JIS K 6238-1. Specifically, 10 g of the acrylic rubber after drying and cooling was placed in an oven at 105 ± 5 ° C., drying was performed until the mass did not substantially change, and the amount of mass loss before and after drying was calculated. And a mass reduction rate is calculated | required from the calculated mass reduction amount, and this was made into moisture content (heat loss) (unit: weight%).

[Mooney Scorch]
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 value of 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 of 15 cm long, 15 cm wide and 0.2 cm deep, and is primary crosslinked by pressing at 170 ° C. for 20 minutes while being pressurized at a pressing pressure of 10 MPa, and then the obtained primary crosslinked The product was heated at 170 ° C. for 4 hours in a gear oven for secondary crosslinking to obtain a sheet-like rubber crosslinked product. The cross-linked rubber obtained was punched with a JIS No. 3 dumbbell to prepare a test piece. Then, using the obtained test piece, according to JIS K6251, the tensile strength, elongation and 100% tensile stress of the rubber crosslinked material, and according to JIS K6253, using the durometer hardness tester type A The hardness was measured respectively.

Production Example 1
In a mixing vessel 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 Sodium lauryl sulfate (trade name "Emar 2 FG", manufactured by Kao Corp.) 0.567 parts as a surfactant, and polyoxyethylene dodecyl ether as a nonionic surfactant (trade name "Emulgen 105", manufactured by Kao Corp.) A monomer emulsion was obtained by charging 1.4 parts and stirring.

  Next, 170.853 parts of pure water and 2.97 parts of the monomer emulsion obtained above are charged into a polymerization reaction tank equipped with a thermometer and a stirrer, and the temperature is 12 ° C. in a nitrogen stream. It cooled down. Then, in the polymerization reaction tank, 145.29 parts of the monomer emulsion obtained above, 0.00033 parts of ferrous sulfate as a reducing agent, 0.264 parts of sodium ascorbate as a reducing agent, and Then, 7.72 parts (0.22 parts as the amount of potassium persulfate) of a 2.85% by weight aqueous solution of potassium persulfate as a polymerization initiator was continuously added dropwise over 3 hours. Thereafter, the reaction was continued for 1 hour while maintaining the temperature in the polymerization reaction vessel at 23 ° C., and it was confirmed that the polymerization conversion reached 97%, and the hydroquinone as a polymerization terminator was added to perform polymerization. The reaction was stopped to obtain an emulsion polymerization solution.

  Then, 100 parts of the emulsion polymerization solution obtained by polymerization, stearyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an anti-aging agent (trade name “Irganox 1076”, BASF Manufactured by Toray Industries, Ltd.) (total of the monomers used in preparation of the emulsion polymerization liquid (ie, ethyl acrylate, n-butyl acrylate, 10 parts of 2-methoxyethyl acrylate, monomaleate) 1 part per 100 parts of n-butyl), 0.011 part of polyethylene oxide (weight average molecular weight (Mw) = 100,000) (total of the monomers used for preparation of the emulsion polymerization liquid) 0.039 parts per 100 parts), and polyoxyethylene stearyl ether phosphoric acid as a lubricant (trade name “Phosphanol RL-210”, Toho A mixed solution was obtained by mixing 0.075 parts (manufactured by Gakuin Kogyo Co., Ltd.) (0.25 parts with respect to a total of 100 parts of the monomers used for preparing the emulsion polymerization liquid). Then, the obtained mixed solution is transferred to a coagulating tank, 60 parts of industrial water is added to 100 parts of the mixed solution, and the mixture is heated to 85 ° C., and then the mixed solution is stirred at a temperature of 85 ° C. While coagulating the polymer by continuously adding 3.3 parts of sodium sulfate (11 parts with respect to 100 parts of the polymer contained in the mixed solution) as a coagulant, it is separated by filtration. I got a water-containing crumb.

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

  Next, an aqueous sulfuric acid solution (pH = 3) obtained by mixing 388 parts of industrial water and 0.13 parts of concentrated sulfuric acid is added to 100 parts of the solid content of the water-containing crumb washed with water as described above, and the coagulating tank After stirring for 5 minutes at room temperature, the water-containing crumb was pickled by draining water from the coagulation tank. The pH of the water-containing crumb after pickling (pH of water in the water-containing crumb) was measured, pH = 3. Next, 388 parts of pure water is added to 100 parts of solid content of the acid-washed water-containing crumb, and after stirring for 5 minutes at room temperature in the coagulation tank, the water-containing crumb is discharged by discharging water from the coagulation tank. The water-containing crumb of acrylic rubber (A1) was obtained by performing pure water washing | cleaning of this.

Example 1
In Production Example 1, the extrusion type drier 1 having the configuration shown in FIG. 1 and the conveyance type cooling device 5 shown in FIG. 2 directly connected to the dry rubber outlet of the die 4 of the extrusion type drier 1 are shown. Drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 were continuously performed using the above. Specifically, the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 is subjected to a dehydration treatment using an expeller, and then the water-containing crumb after the dehydration treatment is an extrusion type having the configuration shown in FIG. Dewatering and drying are carried out by continuously feeding to the feed port 310 of the dryer 1, and the sheet-like dried rubber discharged and continuously extruded from the die 4 of the extrusion type dryer 1 is shown in FIG. The sheet-like acrylic rubber was continuously manufactured by continuously cooling in the conveyance type cooling device 5 shown to. In addition, as the conveyance type cooling device 5 shown in FIG. 2, the thing of 40 m in length L 1 of the conveyor 6 and the cooling means 7 was used.

  In the first embodiment, the residence time in the conveyance type cooling device 5 (that is, the time when the dry rubber passes the distance L1 between the conveyor 6 and the cooling means 7) is 0.5 hours. Dewatering and drying by the extrusion type drier 1 and cooling of the conveyance type cooling device 5 were performed. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 15 ° C.

  In Example 1, the temperature T1 of the dry rubber at the time of discharge from the die 4 of the extrusion type dryer 1 is 160 ° C., and from the time of the sheet-like dry rubber being discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 0.45 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 267 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 27 ° C., and the thickness of the sheet-like dry rubber was 20 mm. In addition, the measurement of the thickness of sheet-like dry rubber was performed by the following method. That is, the sheet-like dry rubber is cut 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 in the obtained cut surface with a caliper is The measurement was carried out on five cut surfaces, and the average value of the measurement results obtained at five positions was determined, and this was used as the thickness of the sheet-like dry rubber (Examples 2 to 6 and Comparative Examples 1 to 4 described later) As well).

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. The Mooney viscosity (polymer Mooney) of acrylic rubber is 33, and the composition of acrylic rubber is 5% by weight of ethyl acrylate unit, 63% by weight of n-butyl acrylate unit, and 30% by weight of 2-methoxyethyl acrylate unit And the mono n-butyl maleate unit was 2% by weight (the composition of the acrylic rubber is the same as in Examples 2 to 5 and Comparative Examples 1 to 3 described later).

  Subsequently, to 100 parts of the sheet-like acrylic rubber obtained above, 60 parts of FEF carbon (trade name "Seat SO", manufactured by Tokai Carbon Co., Ltd.), 2 parts of stearic acid, higher fatty acid ester (trade name "GREK" 1 part of G8205 ", Dainippon Ink Co., Ltd., and 2 parts of 4, 4'-bis (α, α-dimethylbenzyl) diphenylamine (trade name" NOCRACK CD ", Ouchi emerging chemical industry company) And mixed at 50 ° C. for 5 minutes. Next, the resulting mixture is transferred to a roll at 50 ° C., 0.6 part of hexamethylene diamine carbamate (trade name “Diak # 1, manufactured by DuPont Dow Elastomer, aliphatic polyhydric amine compound), and 1,3 1,3 -The acrylic rubber composition was obtained by mix | blending 2 parts of-di- o- tolyl guanidine (brand name "Noxceler DT", the Ouchi emerging chemical company make, bridge | crosslinking accelerator), and knead | mixing.

  And each measurement of Mooney viscosity (compound Mooney), Mooney scorch, and physical properties (tensile strength, elongation, 100% tensile stress, hardness) was performed using the obtained acrylic rubber composition. The results are shown in Table 1.

Example 2
Also in Example 2, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Example 2, dehydration and drying by the extrusion dryer 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 0.75 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 21 ° C.

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

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 32.

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

[Example 3]
In the third embodiment, the same extrusion type drier 1 and conveyance type cooling device 5 as in the first embodiment are used, while the water cooling device (sheet is placed between the extrusion type drier 1 and the conveyance type cooling device 5 Device for cooling by continuously immersing the rubber-like dry rubber in water), the extrusion type drier 1, the water-cooling device and the conveyance type cooling device 5 are used, and the production example 1 is performed. Drying and cooling of the water-containing crumb of the obtained acrylic rubber (A1) were continuously performed. In Example 3, the dewatering and drying by the extrusion dryer 1 are performed under the condition that the residence time in the water cooling device is 0.1 hours, and then the residence time in the conveyance type cooling device 5 is 0.4 hours. And cooling by the water-cooling device and the transfer type cooling device 5 were performed. The water cooling apparatus kept the water temperature at 20 ° C., and the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 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 type dryer 1 is 160 ° C., and from the time when the sheet-like dry rubber is discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 0.35 hours, and the cooling of the temperature of the drying rubber is cooled to 40 ° C from the point when the drying rubber is extruded from the extrusion dryer 1 and discharged. The rate V1 was 343 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 21 ° C., and the thickness of the sheet-like dry rubber was 21 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 35.

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

Example 4
Also in Example 4, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Example 4, dehydration and drying by the extrusion type drier 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 1.5 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 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 type dryer 1 is 160 ° C., and from the time of the sheet-like dry rubber being discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 1.23 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 98 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 15 ° C., and the thickness of the sheet-like dry rubber was 25 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 34.

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

[Example 5]
Also in Example 5, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Example 5, dewatering and drying by the extrusion type drier 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 0.4 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 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 type dryer 1 is 160 ° C., and from the time when the sheet-like dry rubber is discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 0.38 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 316 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 35 ° C., and the thickness of the sheet-like dry rubber was 23 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 33.

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

Comparative Example 1
Also in Comparative Example 1, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Comparative Example 1, dehydration and drying by the extrusion dryer 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 4 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 33 ° C. In Comparative Example 1, since the temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 exceeded 40 ° C., after being discharged from the conveyance type cooling device 5, the temperature was kept still at room temperature (23 ° C.). The temperature of the sheet-like dry rubber was lowered to 40 ° C. by placing. The time required for the temperature to drop to 40 ° C. after discharging from the conveyance type cooling device 5 was 2.12 hours.

  In Comparative Example 1, the temperature T1 of the dry rubber at the time of discharge from the die 4 of the extrusion type dryer 1 is 160 ° C., and from the time of the sheet-like dry rubber being discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 6.12 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, it is cooled when the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 20 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 65 ° C., and the thickness of the sheet-like dry rubber was 26 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 33.

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

Comparative Example 2
Also in Comparative Example 2, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Comparative Example 2, dehydration and drying by the extrusion dryer 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 0.5 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 15 ° C. In Comparative Example 2 as well, the temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 exceeded 40 ° C. Therefore, after being discharged from the conveyance type cooling device 5, the temperature was kept still at room temperature (23 ° C.). The temperature of the sheet-like dry rubber was lowered to 40 ° C. by placing. The time taken for the temperature to drop to 40 ° C. after discharging from the conveyance type cooling device 5 was 2.63 hours.

  In Comparative Example 2, the temperature T1 of the dry rubber at the time of discharge from the die 4 of the extrusion type dryer 1 is 160 ° C., and 40 of the sheet-like dry rubber is discharged from the extrusion type dryer 1 The time P1 required for the temperature to drop to ° C is 3.13 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, the temperature of the dry rubber is cooled down to 40 ° C. The rate V1 was 38 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 70 ° C., and the thickness of the sheet-like dry rubber was 24 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 35.

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

Comparative Example 3
Also in Comparative Example 3, drying and cooling of the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Comparative Example 3, dehydration and drying by the extrusion dryer 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 4.5 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 30 ° C.

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

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 34.

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

[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 is dried by the extrusion dryer 1, the dry rubber is extruded from the extrusion dryer 1 and the temperature of the drying rubber is cooled to 40 ° C. The acrylic rubber obtained by performing cooling under the condition that the cooling speed V1 at the time of curing is 40.degree. C./hour or more is a scorch time when compounding agents such as a crosslinking agent are blended to form an acrylic rubber composition. t5 is long, the scorch during processing is effectively suppressed, and further, the increase value of Mooney viscosity (the difference between the polymer Mooney viscosity and the compound Mooney viscosity) by the addition of the compounding agent is small, whereby the processing stability is excellent (Examples 1-5).
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 is short in the case of using an acrylic rubber composition, and scorch tends to occur at the time of processing. The increase value of the Mooney viscosity (the difference between the polymer Mooney viscosity and the compound Mooney viscosity) due to the addition of the agent was also large, and the processability was inferior (Comparative Examples 1 to 3).

Production Example 2
While changing the amount of ethyl acrylate used from 5 to 48 parts and the amount of n-butyl acrylate used from 63 parts to 50 parts, Production Example 1 was used except that 2-methoxyethyl acrylate was not used. In the same manner as in the above, a water-containing crumb of acrylic rubber (A2) was obtained.

[Example 6]
In Example 6, using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1, replacing the water-containing crumb of the acrylic rubber (A1) obtained in Production Example 1 with Drying and cooling of the water-containing crumb of acrylic rubber (A2) were continuously performed. In Example 6, dewatering and drying by the extrusion type drier 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 0.5 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 15 ° C.

  In Example 6, the temperature T1 of the dry rubber at the time of discharge from the die 4 of the extrusion type dryer 1 is 160 ° C., and from the time of the sheet-like dry rubber being discharged from the extrusion type dryer 1, 40 The time P1 required for the temperature to drop to ° C is 0.46 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 261 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 30 ° C., and the thickness of the sheet-like dry rubber was 26 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. The Mooney viscosity (polymer Mooney) of the acrylic rubber is 30, and the composition of the acrylic rubber is 48% by weight of ethyl acrylate unit, 50% by weight of n-butyl acrylate unit, 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).

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

Comparative Example 4
Also in Comparative Example 4, drying and cooling of the water-containing crumb of the acrylic rubber (A2) obtained in Production Example 2 are continuously performed using the same extrusion type dryer 1 and conveyance type cooling device 5 as in Example 1. The In Comparative Example 4, dehydration and drying by the extrusion dryer 1 and cooling by the conveyance type cooling device 5 were performed under the condition that the residence time in the conveyance type cooling device 5 is 3.5 hours. Further, the temperature of the cooling air blown to the sheet-like dry rubber from the cooling means 7 provided in the conveyance type cooling device 5 was 30 ° C. In Comparative Example 4, since the temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 exceeded 40 ° C., after being discharged from the conveyance type cooling device 5, the temperature was kept still at room temperature (23 ° C.). The temperature of the sheet-like dry rubber was lowered to 40 ° C. by placing. The time required for the temperature to drop to 40 ° C. after discharging from the conveyance type cooling device 5 was 0.92 hours.

  In Comparative Example 4, the temperature T1 of the dry rubber at the time of discharge from the die 4 of the extrusion type dryer 1 is 160 ° C., and 40 of the sheet-like dry rubber is discharged from the extrusion type dryer 1 The time P1 required for the temperature to drop to ° C is 4.42 hours, and when the dry rubber is extruded from the extrusion dryer 1 and discharged, it is cooled when the temperature of the dry rubber is cooled to 40 ° C. The rate V1 was 27 ° C./hour. The temperature of the sheet-like dry rubber discharged from the conveyance type cooling device 5 was 64 ° C., and the thickness of the sheet-like dry rubber was 23 mm.

  And when the moisture content was measured about the obtained sheet-like acrylic rubber, it was a thing which does not contain water substantially and was 0 weight%. In addition, the Mooney viscosity (polymer Mooney) of the acrylic rubber was 33.

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

Evaluation of Example 6 and Comparative Example 4
As shown in Table 2, dry rubber is similarly extruded from the extrusion dryer 1 and discharged from the extrusion type dryer 1 when acrylic rubber containing no (meth) acrylic acid alkoxy alkyl ester monomer unit is used. The compounding agent such as the cross-linking agent is compounded by performing cooling under the condition that the cooling speed V1 when the temperature of the dry rubber is cooled to 40 ° C. becomes 40 ° C./hour or more from the time point of drying. In this case, the scorch time t5 was long, and the scorch at the time of 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 6 ... Conveyor 7 ... Cooling means

Claims (5)

A method of producing acrylic rubber,
Drying the water-containing crumb of acrylic rubber with an extrusion type dryer;
Cooling the dried rubber extruded and discharged from the extrusion dryer to 40 ° C. or lower,
The manufacturing method of the acrylic rubber which makes the cooling rate at the time of cooling to 40 degreeC after discharging | emitting from the said extrusion type dryer make cooling rate at 40 degrees C / hr or more, when cooling the said dry rubber.   The acrylic according to claim 1, wherein when the dry rubber is extruded from the extrusion dryer, it is extruded from the extrusion dryer as a sheet-like rubber having a thickness of 9 mm or more, and the drying rubber is cooled in a sheet form. How to make rubber.   The method for producing an acrylic rubber according to claim 1, wherein the acrylic rubber contains a (meth) acrylic acid alkoxyalkyl ester monomer unit.   The manufacturing method of the acrylic rubber composition provided with the process of mix | blending a crosslinking agent with the acrylic rubber obtained by the manufacturing method in any one of Claims 1-3.   A method for producing a rubber cross-linked product, comprising the step of crosslinking the acrylic rubber composition obtained by the production method according to claim 4.

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