JP2021017547A - Acrylic rubber bale excellent in storage stability and water resistance - Google Patents

Abstract

To provide an acrylic rubber bale excellent in storage stability and water resistance, a method of producing thereof, a rubber mixture, a method of producing thereof, and a rubber crosslinked product thereof.SOLUTION: The acrylic rubber bale pertaining to the present invention has an ash content of 0.2 wt.% or less, a total amount of sodium and sulfur in ash of 30 wt.% or more, a weight ratio of sodium to sulfur in a specific range, and is excellent in storage stability and water resistance. The acrylic rubber bale is produced through: an emulsion polymerization process of subjecting monomer constituents including (meth)acrylic acid ester, and a reactive group-containing monomer to emulsion polymerization using a sulfuric acid-based emulsifier; a coagulation process of generating a hydrous crumb by contacting an obtained emulsion polymerization liquid with a coagulant aqueous solution; a washing process of washing the hydrous crumb; a dehydrating, drying, molding process of dehydrating and drying the washed hydrous crumb under a specific condition using a screw-type extruder, and extruding a sheet-like dried rubber; and a baling process of baling the sheet-like dried rubber by laminating.SELECTED DRAWING: None

Description

The present invention relates to an acrylic rubber bale and its manufacturing method, a rubber mixture and its manufacturing method, and a rubber crosslinked product. More specifically, an acrylic rubber bale having excellent storage stability and water resistance and its manufacturing method, the acrylic rubber bale. The present invention relates to a rubber mixture containing the mixture, a method for producing the same, and a rubber crosslinked product obtained by cross-linking the rubber mixture.

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

Such acrylic rubber is usually emulsion-polymerized with the monomer components constituting the acrylic rubber, brought into contact with the obtained emulsion polymerization solution and a coagulant, and the obtained hydrous crumb is dried and then veiled and commercialized. To.

For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2006-328239) describes a step of obtaining a crumb slurry containing a crumb-like rubber polymer by bringing a polymer latex into contact with a coagulating liquid, and a stirring power of 1 kW / m3 or more. A step of crushing the crumb-shaped rubber polymer contained in the crumb slurry with a mixer having a stirring / crushing function, and dehydration of removing water from the crumb slurry in which the crumb-shaped rubber polymer is crushed to obtain a crumb-shaped rubber polymer. A method for producing a rubber polymer comprising a step and a step of heating and drying the moisture-removed crumb-like rubber polymer is disclosed, and the dried crumb is introduced into a baler in the form of flakes, compressed and veiled. It is stated that it will be polymerized. As the rubber polymer used here, an unsaturated nitrile-conjugated diene copolymer latex obtained by emulsification polymerization is specifically shown, and ethyl acrylate / n-butyl acrylate copolymer and ethyl acrylate / It has been shown that it can be applied to a copolymer composed only of an acrylate such as an n-butyl acrylate / 2-methoxyethyl acrylate copolymer. However, acrylic rubber composed only of acrylate has a problem that it is inferior in crosslinked rubber characteristics such as heat resistance and compression set characteristics.

Examples of acrylic rubber having a reactive group having excellent heat resistance and compressive permanent strain are described in Patent Document 2 (International Publication No. 2018/116828 pamphlet) as ethyl acrylate, n-butyl acrylate and mono n fumarate. Acrylic rubber latex obtained by emulsifying a monomer component composed of butyl with sodium lauryl sulfate as an emulsifier, polyethylene glycol monostearate and water, and emulsion polymerization in the presence of a polymerization initiator until the polymerization conversion rate reaches 95%. After adding magnesium sulfate to an aqueous solution of a polymer flocculant dimethylamine-ammonia-epichlorohydrin polycondensate, the mixture is stirred at 85 ° C. to form a crumb slurry, and then the crumb slurry is washed once with water. A method of recovering a crumb-shaped acrylic rubber by passing the entire amount through a 100-mesh wire net to capture only the solid content is disclosed. According to this method, it is described that the obtained hydrous crumb is dehydrated by centrifugation or the like, dried at 50 to 120 ° C. by a band dryer or the like, introduced into a baler, compressed and veiled. There is. However, this method has problems such as a large number of semi-coagulated hydrous crumbs generated in the coagulation reaction and a large amount of adhering to the coagulation tank, and problems such as insufficient removal of coagulants and emulsifiers by washing. Even if it was produced, there was a problem that it was inferior in storage stability and water resistance.

Further, in Patent Document 3 (International Publication No. 2018/079783 pamphlet), a monomer component composed of ethyl acrylate, n-butyl acrylate and mono n-butyl fumarate is contained in pure water, sodium lauryl sulfate and polyoxy. Emulsified using an emulsifier made of ethylene dodecyl ether and emulsion-polymerized to a polymerization conversion rate of 95% by weight in the presence of a polymerization initiator to obtain an emulsion polymerization solution, and a hydrous crumb is produced by continuously adding sodium sulfate. Then, the produced hydrous crumb was washed with industrial water four times, acid-washed at pH 3 once, and pure water-washed once, and then dried at 110 ° C. for 1 hour in a hot air dryer. A method for producing an acrylic rubber having an excellent water resistance (volume change after immersion in 80 ° C. distilled water for 70 hours) with a small residual amount of an emulsifier or a coagulant is disclosed. However, it is not described that it is molded into a veil shape and used, and handling the adhesive acrylic rubber in a crumb shape has a problem that workability and storage stability are inferior. Also, regarding water resistance, a high degree of water resistance in a harsher environment is required.

On the other hand, regarding the production of sheet-shaped acrylic rubber, for example, Patent Document 4 (Japanese Unexamined Patent Publication No. 1-225512) describes biaxial extrusion drying including a feed barrel, a dehydration barrel, a standard barrel, a vent barrel, and a vacuum barrel. Using a machine, nitrile rubber (NBR) crumb with a water content of about 50% is supplied to the feed barrel, most of the water is dehydrated in the dehydration barrel, and then the residual water and evaporated vaporized material are sucked and removed in the vacuum barrel, and the breaker. A method of continuously extruding in a strip shape through a plate and a die portion is disclosed, and it is described that an acrylic rubber crumb is used as an applied rubber crumb. However, the patent document does not describe veiling using such an acrylic rubber sheet.

Japanese Unexamined Patent Publication No. 2006-328239 International Publication No. 2018/116828 Pamphlet International Publication No. 2018/079783 Pamphlet Japanese Unexamined Patent Publication No. 1-225512

The present invention has been made in view of such circumstances, and an acrylic rubber bale having excellent storage stability and water resistance and a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber bale and the method for producing the same, and a rubber cross-linking thereof. The purpose is to provide things.

As a result of diligent research in view of the above problems, the present inventors have made acrylic rubber having a reactive group, the amount of ash is in a specific range, and the amount of specific elements in the ash and their ratios are in a specific range. We found that by bale acrylic rubber, storage stability and water resistance are highly excellent.

The present inventors also preserve the acrylic rubber veil by setting the monomer composition of the acrylic rubber having a reactive group, the complex viscosity at 60 ° C. and 100 ° C., the gel amount, the specific gravity and the water content within a specific range. We have found that stability and water resistance are further improved.

The present inventors also produced such an acrylic rubber veil by contacting an emulsion polymerization solution obtained by emulsion polymerization of a monomer component containing a (meth) acrylic acid ester and a reactive group-containing monomer with a coagulation solution. It has been found that a hydrous crumb can be easily produced by dehydrating and drying using a specific screw type extruder, extruding it into a sheet, and laminating it.

The present inventors further include an emulsifier and a coagulant, a method of contacting the emulsion polymerization solution and the coagulation liquid in the coagulation step, a water-containing crumb temperature to be charged into a screw type extruder, a sheet-like dry rubber cutting temperature, and a sheet-like dry rubber lamination. It was found that by specifying the temperature, it is possible to more efficiently produce an acrylic rubber veil having excellent storage stability and water resistance.

The present inventors have completed the present invention based on these findings.

Thus, according to the present invention, it is made of acrylic rubber having a reactive group, the ash content is 0.2% by weight or less, the total amount of sodium and sulfur in the ash content is 30% by weight or more, and the sodium and the above are described. Acrylic rubber veil having a ratio to sulfur ([Na] / [S]) in the range of 0.4 to 2.5 by weight is provided.

In the acrylic rubber veil of the present invention, the amount of ash contained therein is preferably 0.15% by weight or less.

In the acrylic rubber veil of the present invention, it is preferable that the acrylic rubber is mainly composed of (meth) acrylic acid ester, and the acrylic rubber is composed of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. It is more preferable that it contains at least one (meth) acrylic acid ester selected from the group.

The acrylic rubber veil of the present invention preferably has a reactive group content of 0.01% by weight or more.

In the acrylic rubber veil of the present invention, the complex viscosity at 60 ° C. ([η] 60 ° C.) is preferably 15,000 Pa · s or less. The ratio of the complex viscosity at 100 ° C. ([η] 100 ° C.) to the complex viscosity at 60 ° C. ([η] 60 ° C.) ([η] 100 ° C./[η] 60 ° C.) is 0.5. The above is preferable.

Further, in the acrylic rubber veil of the present invention, the specific gravity is in the range of 0.7 to 1.5, the gel amount is 50% by weight or less, and the water content is less than 1% by weight. Each is preferable. Furthermore, the specific gravity is preferably in the range of 0.8 to 1.4.

Further, according to the present invention, a monomer component containing a (meth) acrylic acid ester and a reactive group-containing monomer is emulsion-polymerized using water and a sodium sulfate ester as an emulsifier and emulsion polymerization in the presence of a polymerization catalyst. The emulsion polymerization step of obtaining the dehydrated emulsion, the coagulation step of bringing the obtained emulsion into contact with the coagulating liquid to generate a hydrous crumb, the cleaning step of washing the produced hydrous crumb, and the washed hydrous crumb. Using a dehydration barrel with a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip, the dehydration barrel is dehydrated to a water content of 1 to 40% by weight, and then dried to less than 1% by weight in a drying barrel. Provided is a method for producing an acrylic rubber bale, which includes a dehydration / drying / molding step of extruding a sheet-shaped dried rubber from a die and a bale-forming step of laminating and bale the extruded sheet-shaped dried rubber.

In the method for producing an acrylic rubber veil of the present invention, it is preferable that the coagulant is a sulfate and / or a sodium salt.

Further, in the method for producing an acrylic rubber veil of the present invention, the coagulant concentration of the coagulant is preferably 0.5% by weight or more.

In the method for producing an acrylic rubber bale of the present invention, it is preferable that the contact between the emulsion polymerization solution and the coagulation solution is to add the emulsion polymerization solution to the agitated coagulation solution.

Further, in the method for producing an acrylic rubber bale of the present invention, the stirring number of the agitated coagulant is preferably 100 rpm or more, and the peripheral speed of the agitated coagulant is 0.5 m / s. The above is preferable.

In the method for producing an acrylic rubber veil of the present invention, the temperature of the hydrous crumb to be charged into the screw type extruder is preferably 40 ° C. or higher.

In the method for producing an acrylic rubber bale of the present invention, it is preferable that the sheet-shaped dry rubber is laminated after the sheet-shaped dry rubber is cut, and the sheet-shaped dry rubber is cut at 60 ° C. or lower. It is preferably carried out at the rubber temperature.

In the method for producing an acrylic rubber veil of the present invention, it is preferable that the sheet-shaped dry rubber is laminated at a sheet-shaped dry rubber temperature of 30 ° C. or higher.

According to the present invention, there is also provided a rubber mixture obtained by mixing a filler and a cross-linking agent with the acrylic rubber veil.

According to the present invention, there is provided a method for producing a rubber mixture in which a filler and a cross-linking agent are mixed with the acrylic rubber bale by a mixer, and a rubber in which the acrylic rubber bale and the filler are mixed and then the cross-linking agent is mixed. A method for producing a mixture is provided.

Further, according to the present invention, there is provided a rubber crosslinked product obtained by crosslinking the above rubber mixture.

According to the present invention, an acrylic rubber bale having excellent storage stability and water resistance, a method for producing the same, a rubber mixture containing the acrylic rubber veil, a method for producing the same, and a rubber crosslinked product obtained by cross-linking the acrylic rubber veil are provided. ..

It is a figure which shows typically an example of the acrylic rubber manufacturing system used for manufacturing the acrylic rubber veil which concerns on one Embodiment of this invention. It is a figure which shows the structure of the screw type extruder of FIG. It is a figure which shows the structure of the transport type cooling apparatus used as the cooling apparatus of FIG.

The acrylic rubber veil of the present invention is made of acrylic rubber having a reactive group, has an ash content of 0.2% by weight or less, and has a total amount of sodium and sulfur in the ash content of 30% by weight or more. The ratio to the above-mentioned sulfur ([Na] / [S]) is in the range of 0.4 to 2.5 by weight.

<Monomer component>
The acrylic rubber veil of the present invention is composed of acrylic rubber having a reactive group. The reactive group is appropriately selected depending on the intended use without any particular limitation, but preferably at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a halogen group, more preferably a carboxyl group. When it is a functional group which is at least one selected from the group consisting of a group, an epoxy group and a chlorine atom, it is preferable because the cross-linking property of the acrylic rubber veil can be highly improved. As the acrylic rubber having such a reactive group, a reactive group may be imparted to the acrylic rubber by a post-reaction, but a copolymer of a reactive group-containing monomer is preferable.

The acrylic rubber constituting the acrylic rubber veil of the present invention preferably contains (meth) acrylic acid ester, and is selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. It preferably contains at least one (meth) acrylic acid ester. In the present invention, "(meth) acrylic acid ester" is used as a general term for esters of acrylic acid and / or methacrylic acid.

Specific examples of the acrylic rubber having a preferable reactive group include at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester, and a reactive group. Examples thereof include those composed of a contained monomer and other monomers copolymerizable as required.

The (meth) acrylic acid alkyl ester is not particularly limited, but usually has a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms, preferably an alkyl having 1 to 8 carbon atoms (meth). ) Acrylic acid alkyl ester, more preferably a (meth) acrylic acid alkyl ester having an alkyl group having 2 to 6 carbon atoms.

Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, and n- (meth) acrylic acid. Butyl, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate and the like, ethyl (meth) acrylate, (meth) acrylate n-butyl is preferable, and ethyl acrylate and n-butyl acrylate are more preferable.

The (meth) alkoxyalkyl ester is not limited, but usually has a (meth) alkoxyalkyl ester having 2 to 12 alkoxyalkyl groups, preferably a (meth) acrylic acid having 2 to 8 alkoxyalkyl groups. An alkoxyalkyl ester, more preferably a (meth) acrylic acid alkoxyester having an alkoxyalkyl group having 2 to 6 carbon atoms.

Specific examples of the (meth) acrylate alkoxyalkyl ester include methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, and (meth) acrylic. Examples thereof include ethoxymethyl acid, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate and the like. Among these, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate and the like are preferable, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferable.

At least one (meth) acrylic acid ester selected from the group consisting of these (meth) acrylic acid alkyl esters and (meth) acrylic acid alkoxyalkyl esters can be used alone or in combination of two or more in acrylic rubber. Is usually 50% by weight or more, preferably 70 to 99.9% by weight, more preferably 80 to 99.5% by weight, and most preferably 87 to 99% by weight. If the amount of (meth) acrylic acid ester in the monomer component is excessively small, the weather resistance, heat resistance, and oil resistance of the obtained acrylic rubber may decrease, which is not preferable.

The reactive group-containing monomer is appropriately selected according to the intended use without any particular limitation, but is a single amount having at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a halogen group. The body is preferable, and a monomer having at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is more preferable.

The monomer having a carboxyl group is not limited, but an ethylenically unsaturated carboxylic acid can be preferably used. Examples of the ethylenically unsaturated carboxylic acid include ethylenically unsaturated monocarboxylic acid, ethylenically unsaturated dicarboxylic acid, and ethylenically unsaturated dicarboxylic acid monoester, and among these, ethylenically unsaturated dicarboxylic acid monoester. It is preferable that the ester can further enhance the compression resistance to permanent strain when the acrylic rubber is a crosslinked product of rubber.

The ethylenically unsaturated monocarboxylic acid is not limited, but an ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms is preferable, and for example, acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, and cinnamic acid. And so on.

The ethylenically unsaturated dicarboxylic acid is preferably, but is not limited to, an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, for example, butenedioic acid such as fumaric acid and maleic acid, itaconic acid, citraconic acid, and chloromaleic acid. Can be mentioned. The above ethylenically unsaturated dicarboxylic acid includes those existing as anhydrides.

The ethylenically unsaturated dicarboxylic acid monoester is not limited, but is usually an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkyl monoester having 1 to 12 carbon atoms, preferably ethylenic having 4 to 6 carbon atoms. An unsaturated dicarboxylic acid and an alkyl monoester having 2 to 8 carbon atoms, more preferably an alkyl monoester having 4 carbon atoms and 2 to 6 carbon atoms. Specific examples of such ethylenically unsaturated dicarboxylic acid monoesters include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono n-butyl maleate, and monocyclopentyl fumarate. Monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monoalkyl maleate such as monocyclohexyl maleate; monomethyl itaconate, monoethyl itaconate, monon-butyl itaconate, monocyclohexyl itaconate, etc. Acid monoalkyl esters; etc. are mentioned, and among these, mono n-butyl fumarate and mono n-butyl maleate are preferable, and mono n-butyl fumarate is particularly preferable.

Examples of the monomer having an epoxy group include an epoxy group-containing (meth) acrylic acid ester such as glycidyl (meth) acrylate; an epoxy group-containing vinyl ether such as allyl glycidyl ether and vinyl glycidyl ether; and the like.

Examples of the monomer having a halogen group include unsaturated alcohol esters of halogen-containing saturated carboxylic acids, (meth) acrylic acid haloalkyl esters, (meth) acrylic acid haloacyloxyalkyl esters, and (meth) acrylic acids (haloacetylcarbamoyl). Oxy) alkyl esters, halogen-containing unsaturated ethers, halogen-containing unsaturated ketones, halomethyl group-containing aromatic vinyl compounds, halogen-containing unsaturated amides, haloacetyl group-containing unsaturated monomers and the like can be mentioned.

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 the (meth) acrylic acid haloalkyl ester include chloromethyl (meth) acrylic acid, 1-chloroethyl (meth) acrylic acid, 2-chloroethyl (meth) acrylic acid, and 1,2-dichloroethyl (meth) acrylic acid. , (Meta) acrylic acid 2-chloropropyl, (meth) acrylic acid 3-chloropropyl, (meth) acrylic acid 2,3-dichloropropyl and the like. Specific examples of the (meth) acrylic acid haloacyloxyalkyl ester include (meth) acrylic acid 2- (chloroacetoxy) ethyl, (meth) acrylic acid 2- (chloroacetoxy) propyl, and (meth) acrylic acid 3- (chloro). Examples thereof include acetoxy) propyl and 3- (hydroxychloroacetoxy) propyl (meth) acrylate. Specific examples of the (meth) acrylic acid (haloacetylcarbamoyloxy) alkyl ester include (meth) acrylic acid 2- (chloroacetylcarbamoyloxy) ethyl and (meth) acrylic acid 3- (chloroacetylcarbamoyloxy) propyl. 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, 3-chloropropyl allyl ether and the like. Specific examples of the halogen-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, 2-chloroethyl allyl ketone and the like. Specific examples of the halomethyl group-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, p-chloromethyl-α-methylstyrene and the like. Specific examples of the halogen-containing unsaturated amide include N-chloromethyl (meth) acrylamide. Specific examples of the haloacetyl group-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propylallyl ether and p-vinylbenzylchloroacetic acid ester.

These reactive group-containing monomers are used alone or in combination of two or more, and the proportion in the acrylic rubber is usually 0.01 to 20% by weight, preferably 0.1 to 10% by weight, and more. It is preferably 0.5 to 5% by weight, most preferably 1 to 3% by weight.

In the acrylic rubber of the present invention, other monomers (hereinafter referred to as "other monomers") can be used in combination with the above-mentioned monomers, if necessary. The other monomer is not limited as long as it can be copolymerized with the above-mentioned monomer, and for example, aromatic vinyl, ethylenically unsaturated nitrile, acrylamide-based monomer, other olefin-based monomer, etc. Can be mentioned. Examples of the aromatic vinyl include styrene, α-methylstyrene, divinylbenzene and the like, and examples of the ethylenically unsaturated nitrile include acrylonitrile and methacrylonitrile, and examples of the acrylamide-based monomer include acrylonitrile and methacrylonitrile. For example, acrylamide, methacrylamide and the like can be mentioned. Examples of other olefin-based monomers include ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, and butyl vinyl ether.

The above-mentioned other monomers are used alone or in combination of two or more, and the proportion in the acrylic rubber is usually 0 to 30% by weight, preferably 0 to 20% by weight, and more preferably 0 to 15% by weight. Parts, most preferably in the range of 0 to 10 parts by weight.

<Acrylic rubber>
The acrylic rubber constituting the acrylic rubber veil of the present invention is characterized by having a reactive group. The content of the reactive group may be appropriately selected according to the purpose of use, but is usually 0.001 to 5% by weight, preferably 0.01 to 3% by weight, based on the weight ratio of the reactive group itself. Workability, strength properties, compressive permanent strain resistance, oil resistance, cold resistance, water resistance, etc., preferably in the range of 0.05 to 1% by weight, particularly preferably 0.1 to 0.5% by weight, etc. The characteristics are highly balanced and suitable.

Specific examples of the acrylic rubber constituting the acrylic rubber veil of the present invention include at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. It consists of a reactive group-containing monomer and, if necessary, other copolymerizable monomers, and the proportions in each acrylic rubber are (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. At least one (meth) acrylic acid ester selected from the group consisting of is usually 50% by weight or more, preferably 70 to 99.9% by weight, more preferably 80 to 99.5% by weight, and particularly preferably 87 to 9% by weight. In the range of 99% by weight, the amount of the reactive group-containing monomer is usually 0.01 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, and particularly preferably. It is in the range of 1 to 3% by weight, and other monomers are usually 0 to 30% by weight, preferably 0 to 20% by weight, more preferably 0 to 15% by weight, and particularly preferably 0 to 10% by weight. The range. By setting these monomers constituting the acrylic rubber in the above range, the object of the present invention can be highly achieved, and when the acrylic rubber veil is used as a crosslinked product, the water resistance and compression set resistance are remarkably improved. Therefore, it is suitable.

The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber veil of the present invention is not particularly limited, but is an absolute molecular weight measured by GPC-MALS, and is usually 100,000 to 5,000,000, preferably 500. When mixing the acrylic rubber veil, when in the range of 000 to 4,000,000, more preferably 700,000 to 3,000,000, most preferably 1,000,000 to 2,500,000. Workability, strength characteristics and compression set characteristics are highly balanced.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber veil of the present invention is not particularly limited, but is a polymer region measured by GPC-MALS. The workability, strength characteristics and compression resistance of the acrylic rubber bale are usually in the range of 1.1 to 8, preferably 1.2 to 7, and more preferably 1.4 to 6 in the absolute molecular weight distribution with an emphasis on. Highly balanced permanent distortion.

The ratio (Mz / Mw) of the z average molecular weight (Mz) and the weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber veil of the present invention is not particularly limited, but is a polymer region measured by GPC-MALS. The processability and strength characteristics of the acrylic rubber bale are highly balanced when the absolute molecular weight distribution is usually 1.3 or more, preferably 1.4 to 5, and more preferably 1.5 to 2. Moreover, changes in physical properties during storage can be mitigated.

The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber veil of the present invention is not particularly limited, but is usually 20 ° C. or lower, preferably 10 ° C. or lower, and more preferably 0 ° C. or lower. The lower limit of the glass transition temperature (Tg) is not particularly limited, but is usually −80 ° C. or higher, preferably −60 ° C. or higher, and more preferably −40 ° C. or higher. By setting the glass transition temperature to the above-mentioned lower limit or higher, the oil resistance and heat resistance can be improved, and by setting the glass transition temperature to the above-mentioned upper limit or lower, the cold resistance and workability can be improved.

The content of acrylic rubber in the acrylic rubber veil of the present invention is appropriately selected depending on the intended use, but is usually 95% by weight or more, preferably 97% by weight or more, and more preferably 98% by weight or more.

<Acrylic rubber veil>
The acrylic rubber veil of the present invention is made of the acrylic rubber, and is characterized in that the ash content and the ash content are specific. The ash content in the acrylic rubber veil is measured according to the JIS K6228 A method. In the production of acrylic rubber, the emulsifier used for emulsion polymerization and the emulsion polymerization solution are coagulated. The residue of the coagulant used in this case is the main component.

The size of the acrylic rubber veil of the present invention is not particularly limited, but the width is usually in the range of 100 to 800 mm, preferably 200 to 500 mm, more preferably 250 to 450 mm, and the length is usually 300 to 1200 mm, preferably 400. It is in the range of ~ 1000 mm, more preferably 500 to 800 mm, and the height is usually in the range of 50 to 500 mm, preferably 100 to 300 mm, more preferably 150 to 250 mm.

The ash content of the acrylic rubber veil of the present invention is. When it is 0.2% by weight or less, preferably 0.15% by weight or less, more preferably 0.12% by weight or less, particularly preferably 0.11% by weight or less, and most preferably 0.1% by weight or less. It is suitable because it has excellent storage stability and water resistance.

The lower limit of the ash content of the acrylic rubber veil of the present invention is not limited, but is usually 0.0001% by weight or more, preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, and particularly preferably 0. When it is 005% by weight or more, most preferably 0.01% by weight or more, metal adhesion is suppressed and workability is excellent and suitable.

The amount of ash that highly balances the storage stability, water resistance, and metal adhesion of the acrylic rubber sheet of the present invention is usually 0.0001 to 0.2% by weight, preferably 0.0005 to 0.15% by weight. It is more preferably 0.001 to 0.12% by weight, particularly preferably 0.05 to 0.11% by weight, and most preferably 0.01 to 0.1% by weight.

When the total amount of sodium and sulfur in the ash content of the acrylic rubber veil of the present invention is 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more. It has excellent storage stability and water resistance and is suitable.

The ratio of sodium to sulfur ([Na] / [S]) in the ash content of the acrylic rubber veil of the present invention is 0.4 to 2.5 by weight, preferably 0.6 to 2, preferably 0. When it is in the range of 8 to 1.7, more preferably 1 to 1.5, the water resistance is highly excellent and suitable.

The water content of the acrylic rubber veil of the present invention is not particularly limited, but the vulcanization characteristics are usually optimal when it is less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. It is suitable because it has excellent properties such as heat resistance and water resistance.

The specific gravity of the acrylic rubber veil of the present invention is not particularly limited, but is usually 0.7 to 1.5, preferably 0.8 to 1.4, more preferably 0.9 to 1.3, particularly. When it is preferably in the range of 0.95 to 1.25, most preferably 1.0 to 1.2, the storage stability is highly excellent and suitable.

The gel amount of the acrylic rubber veil of the present invention is not particularly limited, but is an insoluble content of methyl ethyl ketone, usually 50% by weight or less, more preferably 30% by weight or less, particularly preferably 10% by weight or less, most preferably. When it is preferably 5% by weight or less, the workability is highly improved and is preferable. The amount of gel in the acrylic rubber veil of the present invention is a methyl ethyl ketone insoluble component, but it does not correlate with the amount of THF (tetrahydrofuran) insoluble gel in a different solvent, and has characteristics depending on the solvent used. The gel amount was different.

The pH of the acrylic rubber sheet of the present invention is not particularly limited, but is usually 6 or less, preferably 2 to 6, more preferably 2.5 to 5.5, and particularly preferably 3 to 5. , The storage stability is highly improved and suitable when it is in this range.

The complex viscosity ([η] 60 ° C.) of the acrylic rubber veil of the present invention at 60 ° C. is not limited, but is usually 15,000 Pa · s or less, preferably 2,000 to 10,000 Pa. When it is in the range of s, more preferably 2,500 to 7,000 Pa · s, and most preferably 2,700 to 5,500 Pa · s, it is excellent in processability, oil resistance and shape retention.

The complex viscosity ([η] 100 ° C.) of the acrylic rubber veil of the present invention at 100 ° C. is not particularly limited, but is usually 1,500 to 6,000 Pa · s, preferably 2,000 to 5, When it is in the range of 000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s, it is excellent in workability, oil resistance, and shape retention. is there.

The ratio of the complex viscosity ([η] 100 ° C.) of the acrylic rubber veil of the present invention at 100 ° C. to the complex viscosity ([η] 60 ° C.) at 60 ° C. ([η] 100 ° C./[η] 60 ° C.) Is not particularly limited, but is usually 0.5 or more, preferably 0.6 to 0.98, more preferably 0.7 to 0.96, particularly preferably 0.8 to 0.95, most preferably. When it is preferably in the range of 0.83 to 0.93, workability, oil resistance, and shape retention are highly balanced and preferable.

The Mooney viscosity (ML1 + 4,100 ° C.) of the acrylic rubber veil of the present invention is not particularly limited, but is usually in the range of 10 to 150, preferably 20 to 100, more preferably 25 to 70. It is suitable because its workability and strength characteristics are highly balanced.

<Manufacturing method of acrylic rubber veil>
The above-mentioned method for producing an acrylic rubber bale is not particularly limited, but (a) a dehydration ester using a monomer component containing a (meth) acrylic acid ester and a reactive group-containing monomer as water and an emulsifier. A hydropolymerization step of emulsifying with a sodium salt and emulsifying and polymerizing in the presence of a polymerization catalyst to obtain an emulsified polymer solution, and (b) contacting the obtained emulsified polymer solution with a coagulating solution (coagulant-containing aqueous solution) to form a hydrous crumb. The solidification step to be generated, (c) the washing step to wash the generated water-containing crumb, and (d) the washed water-containing crumb, a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type having a die at the tip. A dehydration / drying / molding step of dehydrating to a water content of 1 to 40% by weight in a dehydration barrel using an extruder, drying to less than 1% by weight in a drying barrel, and extruding a sheet-shaped dry rubber from the die, and (e) extruding. It can be easily manufactured by a manufacturing method including a bale step of laminating and bale the sheet-shaped dried rubber.

(Emulsion polymerization process)
In the emulsion polymerization step in the method for producing an acrylic rubber bale of the present invention, a monomer component containing a (meth) acrylic acid ester and a reactive group-containing monomer is emulsionized with water and a sodium sulfate as an emulsifier. , It is characterized in that an emulsion polymerization solution is obtained by emulsion polymerization in the presence of a polymerization catalyst.

The monomer components used are the same as those exemplified above and those described as a preferred range. The amount of the monomer component used may be appropriately selected so as to have the above composition of the acrylic rubber of the present invention.

The sodium sulfate ester used is not particularly limited as long as it is usually used as an emulsifier. For example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkyl sulfate, poly Examples thereof include sodium oxyethylene alkylaryl sulfate, and sodium lauryl sulfate is preferable.

Each of these sodium sulfates may be used alone or in combination of two or more, and the amount used is usually 0.01 to 10 parts by weight, preferably 0.01 to 10 parts by weight, based on 100 parts by weight of the monomer component. Is in the range of 0.1 to 5 parts by weight, more preferably 1 to 3 parts by weight.

In the present invention, other emulsifiers other than the above sodium sulfate ester can be used, if necessary. Examples of the emulsifier other than the sodium sulfate salt include, but are not limited to, an anionic emulsifier, a cationic emulsifier, and a nonionic emulsifier of the sodium sulfate ester, and a nonionic emulsifier is preferable.

Examples of anionic emulsifiers other than sodium sulfate ester include fatty acid emulsifiers such as sodium octanate, sodium decanoate, sodium laurate, sodium myristate, sodium palmitate, and sodium stearate; sodium hexanesulfonate and octane sulfone. Sodium acid, sodium decane sulfonate, sodium toluene sulfonate, sodium cumene sulfonate, sodium octylbenzene sulfonate, sodium dodecylbenzene sulfonate, ammonium dodecylbenzene sulfonate, sodium naphthalene sulfonate, sodium alkylnaphthalene sulfonate, alkyldiphenyl ether disulfone Sulfonic acid-based emulsifiers such as sodium acid, sulfosuccinic acid-based emulsifiers such as sodium dioctyl sulfosuccinate, sodium dihexyl sulfosuccinate; phosphoric acid emulsifiers such as sodium lauryl phosphate, potassium lauryl phosphate, sodium polyoxyalkylene alkyl ether phosphate And so on.

Examples of the cationic emulsifier include alkyltrimethylammonium chloride, dialkylammonium chloride, and benzylammonium chloride.

Nonionic emulsifiers include, but are not limited to, polyoxyalkylene fatty acid esters such as polyoxyethylene stearic acid esters; polyoxyalkylene alkyl ethers such as polyoxyethylene dodecyl ethers; and polyoxyalkylenes such as polyoxyethylene nonylphenyl ethers. Alkylphenol ether; Polyoxyethylene sorbitan alkyl ester and the like can be mentioned, and polyoxyalkylene alkyl ether and polyoxyalkylene alkylphenol ether are preferable, and polyoxyethylene alkyl ether and polyoxyethylene alkylphenol ether are more preferable.

Other emulsifiers other than these sodium sulfates can be used alone or in combination of two or more, and the amount used can be used as long as the effect of the present invention is not impaired, and is a single amount. It is usually in the range of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the body component.

The method of mixing the monomer component, water and emulsifier may be a conventional method. For example, a method of stirring the monomer, emulsifier and water using a stirrer such as a homogenizer or a disk turbine is adopted. Will be done. The amount of water used is usually in the range of 10 to 750 parts by weight, preferably 50 to 500 parts by weight, and more preferably 100 to 400 parts by weight with respect to 100 parts by weight of the monomer component.

The polymerization catalyst used is not limited as long as it is usually used in emulsion polymerization, and for example, a redox catalyst composed of a radical generator and a reducing agent can be used.

Examples of the radical generator include peroxides and azo compounds, and peroxides are preferable. As the peroxide, an inorganic peroxide or an organic peroxide is used.

Examples of the inorganic peroxide include sodium persulfate, potassium persulfate, hydrogen peroxide, ammonium persulfate and the like. Among these, potassium persulfate, hydrogen peroxide and ammonium persulfate are preferable, and potassium persulfate is particularly preferable. preferable.

The organic peroxide is not particularly limited as long as it is a known organic peroxide used in emulsion polymerization, and is, for example, 2,2-di (4,5-di- (t-butylperoxy) cyclohexyl) propane. 1-di- (t-hexyl peroxy) cyclohexane, 1,1-di- (t-butyl peroxy) cyclohexane, 4,4-di- (t-butyl peroxy) n-butyl valerate, 2,2 -Di- (t-butylperoxy) butane, t-butylhydroperoxide, cumenehydroperoxide, diisopropylbenzenehydroperoxide, paramentanhydroperoxide, benzoyl peroxide, 1,1,3,3-tetraethylbutyl Hydroperoxide, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, diisobutyryl peroxide, Di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disuccinate peroxide, dibenzoyl peroxide, di (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, Diisobutyryl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, 1,1,3,3-tetramethylbutylper Oxyneodecanate, t-hexyl peroxypivarate, t-butylperoxyneodecanate, t-hexyl peroxypivarate, t-butylperoxypivarate, 2,5-dimethyl-2,5-di ( 2-Ethylhexanoylperoxy) hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-3, 5,5-trimethylhexanate, t-hexyl peroxyisopropyl monocarbonate, t-butylperoxyisopropyl monocarbonate, t-buylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-di (Benzoylperoxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di (t) -Butylperoxy) Hexane and the like are mentioned, and among these, diisopropylbenzenehydroperoxide, cumenehydroperoxide, paramentanhydroperoxide, benzoyl peroxide and the like are preferable.

Examples of the azo compound include azobisisobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis [2- (2-imidazolin-2-yl) propane, 2,2. '-Azobis (Propane-2-carboamidine), 2,2'-Azobis [N- (2-carboxyethyl) -2-methylpropaneamide], 2,2'-Azobis {2- [1- (2- (2-) Hydroxyethyl) -2-imidazolin-2-yl] propane}, 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) and 2,2'-azobis {2-methyl-N- [ 1,1-bis (hydroxymethyl) -2-hydroxyethyl] propanamide} and the like.

These radical generators can be used alone or in combination of two or more, and the amount used is usually 0.0001 to 5 parts by weight, preferably 0, based on 100 parts by weight of the monomer component. It is in the range of 0005 to 1 part by weight, more preferably 0.001 to 0.5 part by weight.

The reducing agent can be used without limitation as long as it is used in the redox catalyst of emulsion polymerization, but in the present invention, it is particularly preferable to use at least two kinds of reducing agents. As the at least two types of reducing agents, for example, a combination of a metal ion compound in a reduced state and another reducing agent is suitable.

Examples of the metal ion compound in the reduced state include ferrous sulfate, sodium hexamethylenediamine tetraacetate, ferrous naphthenate, and the like, and among these, ferrous sulfate is preferable. These reduced metal ion compounds can be used alone or in combination of two or more, and the amount used is usually 0.000001 to 0.01 with respect to 100 parts by weight of the monomer component. It is in the range of 0.00001 to 0.001 parts by weight, more preferably 0.00005 to 0.0005 parts by weight.

Examples of the reducing agent other than the metal ion compound in the reduced state include ascorbic acid such as ascorbic acid, sodium ascorbate and potassium ascorbate or a salt thereof; erythorbic acid such as erythorbic acid, sodium erythorbate and potassium erythorbicate. Or salts thereof; sulfites such as sodium hydroxymethane sulfite; sodium sulfite, potassium sulfite, sodium hydrogen sulfite, sodium aldehyde sulfite, potassium hydrogen sulfite sulfite; sodium pyrosulfite, potassium pyrosulfite, sodium pyrosulfite, Pyro sulfites such as potassium hydrogen pyrosulfite; thiosulfates such as sodium thiosulfite and potassium thiosulfite; phosphite, sodium bisulfite, potassium bisulfite, sodium bisulfite, potassium hydrogen phosphite phosphite or salts thereof; Pyrophosphates such as pyrophosphate, sodium pyrophosphate, potassium pyrophosphate, sodium hydrogenpyrophosphate, potassium hydrogenpyrophosphate or salts thereof; sodium formaldehyde sulfoxylate and the like can be mentioned. Among these, alcorbic acid or a salt thereof, sodium formaldehyde sulfoxylate and the like are preferable, and ascorbic acid or a salt thereof is particularly preferable.

The reducing agents other than the metal ion compounds in the reduced state can be used individually or in combination of two or more, and the amount used is usually 0.001 to 0.001 to 100 parts by weight of the monomer component. It is in the range of 1 part by weight, preferably 0.005 to 0.5 parts by weight, and more preferably 0.01 to 0.3 parts by weight.

The ratio of the combination of the metal ion compound in the reducing state and the other reducing agent is not particularly limited, but [the metal ion compound in the reducing state] / [the reducing agent other than the metal ion compound in the reducing state]. When the weight ratio is usually in the range of 1/999999 to 5/5, preferably 1/99999 to 1/9, more preferably 1/9999 to 1/99, and particularly preferably 1/999 to 5/995. It is suitable because the productivity can be highly improved.

A preferable combination of the metal ion compound in the reduced state and the other reducing agent is a combination of ferrous sulfate and ascorbic acid or a salt thereof and / or sodium formaldehyde sulfoxylate, and more preferably ferrous sulfate. A combination of ascorbate and / or sodium formaldehyde sulfoxylate, most preferably a combination of ferrous sulfate and alcorbate. The amount of ferrous sulfate used at this time is usually 0.000001 to 0.01 parts by weight, preferably 0.00001 to 0.001 parts by weight, and more preferably 0, based on 100 parts by weight of the monomer component. In the range of 0.0005 to 0.0005 parts by weight, the amount of ascorbic acid or a salt thereof and / or sodium formaldehyde sulfoxylate used is usually 0.001 to 1 part by weight, preferably 0.001 to 1 part by weight, based on 100 parts by weight of the monomer component. Is in the range of 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.3 parts by weight.

The amount of water used in the emulsion polymerization reaction may be only the one used at the time of emulsification of the above-mentioned monomer component, but is usually 10 to 1000 parts by weight, preferably 50 parts by weight, based on 100 parts by weight of the monomer component used for polymerization. It is adjusted to be in the range of ~ 500 parts by weight, more preferably 80 to 400 parts by weight, and most preferably 100 to 300 parts by weight.

The emulsion polymerization reaction method may be a conventional method, and may be a batch type, a semi-batch type, or a continuous type. The polymerization temperature and the polymerization time are not particularly limited and can be appropriately selected from the type of polymerization initiator used and the like. The polymerization temperature is usually in the range of 0 to 100 ° C., preferably 5 to 80 ° C., more preferably 10 to 50 ° C., and the polymerization time is usually 0.5 to 100 hours, preferably 1 to 10 hours.

The polymerization conversion rate of the emulsion polymerization reaction is not particularly limited, but is usually 80% by weight or more, preferably 90% by weight or more, more preferably 95% by weight or more, and the acrylic rubber bale produced at this time has a strength characteristic. It is excellent and has no monomeric odor and is suitable. A polymerization inhibitor may be used to terminate the polymerization.

(Coagulation process)
The coagulation step in the method for producing an acrylic rubber sheet of the present invention is characterized in that the emulsion polymerization solution obtained in the above emulsion polymerization step is brought into contact with a coagulation liquid (coagulant-containing aqueous solution) to generate a hydrous crumb. ..

The solid content concentration of the emulsion polymerization solution used in the coagulation step is not particularly limited, but is usually adjusted to the range of 5 to 50% by weight, preferably 10 to 45% by weight, and more preferably 20 to 40% by weight. To.

The coagulant used is not particularly limited, but usually a metal salt is used. Examples of the metal salt include alkali metals, Group 2 metal salts of the Periodic Table, and other metal salts, preferably alkali metal salts, Group 2 metal salts of the Periodic Table, more preferably alkali metal salts, and particularly preferably. Is a sodium salt.

Examples of the alkali metal salt include sodium salts such as sodium chloride, sodium nitrate and sodium sulfate; potassium salts such as potassium chloride, potassium nitrate and potassium sulfate; and lithium salts such as lithium chloride, lithium nitrate and lithium sulfate. Of these, sodium salts are preferable, and sodium chloride and sodium sulfate are particularly preferable.

Examples of the Group 2 metal salt of the periodic table include magnesium chloride, calcium chloride, magnesium nitrate, calcium nitrate, magnesium sulfate, calcium sulfate and the like, and calcium chloride and magnesium sulfate are preferable.

Other metal salts include, for example, zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, tin chloride, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate. , Aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, tin sulfate and the like.
In the present invention, the coagulant is preferably a sulfate and / or a sodium salt, the sulfate is a metal salt of the above sulfate, and the sodium salt is the above sodium salt. Among these, sodium sulfate is particularly preferable. ..

These coagulants can be used alone or in combination of two or more, but it is preferable that the coagulant contains a sodium salt. The amount of the coagulant used is usually in the range of 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, and more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the monomer component. When the coagulant is in this range, it is preferable because it can sufficiently improve the coagulation of the acrylic rubber and highly improve the compression set resistance and water resistance when the acrylic rubber veil is crosslinked.

The coagulant concentration of the coagulant used is usually in the range of 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, and particularly preferably 1.5 to 5. It is suitable because the particle size of the hydrous crumb that is sometimes generated can be uniformly focused in a specific region.

The temperature of the coagulating liquid is not limited, but is preferably 40 ° C. or higher, preferably 40 to 90 ° C., more preferably 50 to 80 ° C., to produce a uniform hydrous crumb.

The contact method between the emulsion polymerization solution and the coagulation solution is not particularly limited, but for example, a method of adding the emulsion polymerization solution to the agitated coagulation solution and a method of adding the coagulation solution to the agitated emulsion polymerization solution. However, the method of adding the emulsion polymerization solution to the agitated coagulating liquid makes the shape and crumb diameter of the produced hydrous crumb uniform and focuses, and significantly improves the cleaning efficiency of the emulsifier and coagulant. It can be improved and is suitable.

The rotation speed of the agitated coagulant is represented by the rotation speed of the stirring blade of the stirring device provided with the coagulation bath, and is usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm, and particularly preferably 400. The range is preferably ~ 800 rpm.

It is preferable that the rotation speed is within a range in which the coagulating liquid can be agitated violently to some extent so that the water-containing crumb particle size generated by coagulation can be made small and uniform. It is possible to suppress the formation of large and small ones, and by setting the rotation speed to be equal to or less than the above upper limit, the solidification reaction can be more easily controlled.

The peripheral speed of the coagulated liquid being agitated is represented by the speed of the outer circumference of the stirring blade of the stirrer provided in the coagulation bath. It is preferable because it can suppress the formation of large and small ones, and an appropriate peripheral speed is usually 0.5 m / s or more, preferably 1 m / s or more, more preferably 1.5 m / s or more, and particularly preferably. Is 2 m / s or more, most preferably 2.5 m / s or more. The upper limit of the peripheral speed is not limited, but the solidification reaction can be easily controlled when it is usually 50 m / s or less, preferably 30 m / s or less, more preferably 25 m / s or less, and most preferably 20 m / s or less. It is suitable.

It is produced by setting the above conditions of the coagulation reaction in the coagulation step (contact method, solid content concentration of emulsion polymerization solution, concentration and temperature of coagulation solution, rotation speed and peripheral speed of coagulation solution during stirring, etc.) within a specific range. The shape and crumb diameter of the hydrous crumb are uniform and focused, and the removal of emulsifiers and coagulants during washing and dehydration is remarkably improved, which is suitable.

The hydrous crumbs thus produced preferably satisfy all of the following conditions (a) to (e) when all the hydrous crumbs are sieved with a JIS sieve. The JIS sieve complies with the provisions of Japanese Industrial Standards (JIS Z 8801-1).
(A) The proportion of hydrous crumbs that do not pass through a JIS sieve with an opening of 9.5 mm is 10% by weight or less.
(B) The proportion of hydrous crumbs that pass through a 9.5 mm mesh JIS sieve and do not pass through a 6.7 mm JIS sieve is 30% by weight or less.
(C) The proportion of hydrous crumbs that pass through a 6.7 mm mesh JIS sieve and do not pass through a 710 μm JIS sieve is 20% by weight or more.
(D) The proportion of hydrous crumbs that pass through the JIS sieve with an opening of 710 μm and do not pass through the JIS sieve of 425 μm is 30% by weight or less, and (e) the proportion of hydrous crumbs that pass through the JIS sieve with an opening of 425 μm is 10 weight. %Less than.

When the proportion of the produced hydrous crumb (a) that does not pass through the JIS sieve having an opening of 9.5 mm is 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less, the emulsifier. And the cleaning efficiency of the coagulant can be significantly improved, which is suitable.

The proportion of the water-containing crumbs produced (b) that passed through the 9.5 mm mesh JIS sieve and did not pass through the 6.7 mm JIS sieve was 30% by weight or less, preferably 20% by weight or less, more preferably. When it is 5% by weight or less, the cleaning efficiency of the emulsifier or coagulant can be remarkably improved, which is preferable.

The proportion of hydrous crumbs produced (c) that passed through a 6.7 mm mesh JIS sieve and did not pass through a 710 μm JIS sieve was 20% by weight or more, preferably 40% by weight or more, more preferably 70% by weight. % Or more, most preferably 80% by weight or more, the cleaning efficiency of the emulsifier or coagulant can be remarkably improved, which is preferable.

The proportion of hydrous crumbs produced (d) that passed through a 710 μm mesh JIS sieve and did not pass through a 425 μm JIS sieve was 30% by weight or less, preferably 20% by weight or less, more preferably 15% by weight or less. When it is, the cleaning efficiency of the emulsifier and the coagulant is remarkably improved, and the productivity is also high, which is suitable.

When the proportion of the hydrous crumb (e) that has passed through the JIS sieve having an opening of 425 μm is 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less, the emulsifier or coagulation The cleaning efficiency of the agent is remarkably improved, and the productivity is high, which is suitable.

In the present invention, the proportion of the produced hydrous crumb that passes through the (f) JIS sieve having a mesh size of 6.7 mm and does not pass through the JIS sieve having a mesh size of 4.75 mm is not limited. However, when it is usually 40% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less, the cleaning efficiency of the emulsifier or coagulant is improved and is preferable.

In the present invention, the proportion of the produced hydrous crumb that passes through the (g) JIS sieve with a mesh size of 4.75 mm and does not pass through the JIS sieve with a mesh size of 710 μm is usually 40% by weight or more, preferably 40% by weight or more. When it is 60% by weight or more, more preferably 80% by weight or more, the removal efficiency of the emulsifier and the coagulant at the time of washing and dehydration is remarkably improved, which is preferable.

Further, in the present invention, the proportion of the water-containing crumb that passes through the (h) JIS sieve having a mesh size of 3.35 mm and does not pass through the JIS sieve having a mesh size of 710 μm is usually 20% by weight or more, preferably 20% by weight or more. When it is 40% by weight or more, more preferably 50% by weight or more, particularly preferably 60% by weight or more, and most preferably 70% by weight or more, the removal efficiency of the emulsifier and coagulant during washing and dehydration is remarkably improved. Suitable.

(Washing process)
The cleaning step in the method for producing an acrylic rubber veil of the present invention is a step of cleaning the hydrous crumb produced in the solidification step.

As a cleaning method, a conventional method may be followed. For example, the generated hydrous crumb can be mixed with a large amount of water for cleaning.

The amount of water used in the washing step is not limited, but the amount per washing with water is usually 50 parts by weight or more, preferably 50 to 15,000 parts by weight, based on 100 parts by weight of the above-mentioned monomer component. More preferably, the amount of ash in the acrylic rubber can be effectively reduced in the range of 100 to 10,000 parts by weight, particularly preferably 150 to 5,000 parts by weight, which is preferable.

The temperature of the water used in the cleaning step is not limited, but it is preferable to use warm water because the cleaning efficiency is improved. The temperature of the hot water is not limited, but is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C., and most preferably 60 to 80 ° C., because the cleaning efficiency can be remarkably increased. Is. That is, by setting the temperature of the washing water to the above lower limit temperature or more, the emulsifier and the coagulant are released from the hydrous crumb, and the washing efficiency is further improved.

The washing time is not limited, but is usually in the range of 1 to 120 minutes, preferably 2 to 60 minutes, and more preferably 3 to 30 minutes.

The number of washings (washing with water) is not limited, but is usually 1 to 10 times, preferably a plurality of times, and more preferably 2 to 3 times. From the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber, it is preferable that the number of times of washing with water is large, but the shape of the water-containing crumb and the diameter of the water-containing crumb are set within a specific range as described above. By setting the cleaning temperature within the above range, the number of cleanings can be significantly reduced.

(Dehydration / drying / molding process)
In the dehydration / drying / molding step in the method for producing an acrylic rubber bale of the present invention, the above-cleaned water-containing crumb is subjected to a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip. It is characterized by dehydrating to a water content of 1 to 40% by weight in a dehydration barrel and then drying to less than 1% by weight in a drying barrel to extrude a sheet-shaped dry rubber from a die.

In the present invention, the water-containing crumb supplied to the screw type extruder is preferably one in which free water is removed (drained) after washing.

Draining step In the method for producing an acrylic rubber bale of the present invention, it is preferable to provide a draining step for separating free water from the water-containing crumb after washing with a drainer after the washing step and before the dehydration / drying step. Draining here is suitable for increasing the dehydration efficiency.

As the drainer, a known one can be used without particular limitation, and examples thereof include a wire mesh, a screen, an electric sieve, and the like, preferably a wire mesh and a screen.

The opening of the drainer is not particularly limited, but when it is usually in the range of 0.01 to 5 mm, preferably 0.1 to 1 mm, more preferably 0.2 to 0.6 mm, the water content crumb loss is small. Moreover, draining can be done efficiently, which is suitable.

The water content of the water-containing crumb after draining, that is, the water content of the water-containing crumb added to the dehydration / drying / molding step is not particularly limited, but is usually 50 to 80% by weight, preferably 50 to 70% by weight, more preferably. It is in the range of 50 to 60% by weight.

The temperature of the water-containing crumb after draining, that is, the temperature of the water-containing crumb put into the dehydration / drying / molding step is not particularly limited, but is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C. It is particularly preferably in the range of 55 to 85 ° C, most preferably in the range of 60 to 80 ° C. At this temperature, a water-containing crumb that has a high specific heat of 1.5 to 2.5 KJ / kg · K and is difficult to raise the temperature like the acrylic rubber of the present invention can be efficiently dehydrated and dried using a screw type extruder. Suitable.

Dehydration of hydrous crumbs (dehydration barrel)
Dehydration of the water-containing crumb is performed in a dehydration barrel portion having a dehydration slit provided in the screw type extruder. The opening of the dehydration slit may be appropriately selected according to the conditions of use, but is usually in the range of 0.01 to 5 mm, preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm. In addition, it is suitable because the water-containing crumb loss is small and the water-stopping crumb can be efficiently dehydrated.

The number of dehydration barrels in the screw extruder is not limited, but is usually more than one, preferably 2 to 10, more preferably 3 to 6, and efficient dehydration of the adhesive acrylic rubber. It is suitable for doing well.

There are two ways to remove water from the water-containing crumb in the dehydration barrel: one that removes water from the dehydration slit in liquid form (drainage) and one that removes water in the form of steam (exhaust vapor). Exhaust steam is defined as preliminary drying to distinguish it.
When using a screw type extruder equipped with a plurality of dehydration barrels, it is preferable to combine drainage and exhaust steam to efficiently dehydrate the adhesive acrylic rubber. In the case of a screw type extruder equipped with three or more dehydration barrels, the selection of whether each barrel is a drainage type dehydration barrel or a steam exhaust type dehydration barrel may be appropriately performed according to the purpose of use, but is usually manufactured. To reduce the amount of ash in the acrylic rubber veil, increase the number of drainage barrels, and to reduce the water content, increase the number of exhaust vapor type barrels.

The set temperature of the dehydration barrel is appropriately selected depending on the monomer composition of the acrylic rubber, the ash content, the water content, the operating conditions, etc., but is usually 60 to 150 ° C., preferably 70 to 140 ° C., more preferably 80 to 80 to It is in the range of 130 ° C. The set temperature of the dehydration barrel for dehydrating in the drained state is usually 60 ° C. to 120 ° C., preferably 70 to 110 ° C., and more preferably 80 to 100 ° C. The set temperature of the dehydration barrel for dehydration in the exhausted steam state is usually in the range of 100 to 150 ° C., preferably 105 to 140 ° C., and more preferably 110 to 130 ° C.

The water content after dehydration (drainage) in the drainage type dehydration barrel that squeezes water from the water-containing crumb is not particularly limited, but is usually 1 to 40% by weight, preferably 5 to 40% by weight, and more preferably 5 to 35%. By weight%, particularly preferably 10 to 35% by weight, most preferably 15 to 35% by weight. At this time, productivity and ash removal efficiency are highly balanced and suitable.

When dehydration of adhesive acrylic rubber having a reactive group is carried out using a centrifuge or the like, the acrylic rubber adheres to the dehydration slit portion and is hardly dehydrated (water content is up to about 45 to 55% by weight). ), In the present invention, for example, by using a screw type centrifuge having a dehydration slit and forcibly squeezing with a screw, it is possible to reduce the water content to this extent.

In the case where the drainage type dehydration barrel and the exhaust steam type dehydration barrel are provided, the water content of the water-containing crumb in the drainage type dehydration barrel portion after dehydration is usually 5 to 40% by weight, preferably 10 to 40% by weight, more preferably. Is 15 to 35% by weight, and the water content after preliminary drying in the exhaust steam type dehydration barrel portion is usually 1 to 30% by weight, preferably 3 to 20% by weight, and more preferably 5 to 15% by weight.

By setting the water content after dehydration to be equal to or higher than the above-mentioned lower limit, the dehydration time can be shortened and deterioration of the acrylic rubber can be suppressed, and by making it equal to or lower than the above-mentioned upper limit, the ash content can be sufficiently reduced.

Drying of hydrous crumb (dry barrel)
The hydrous crumb after dehydration is dried in a drying barrel portion under reduced pressure. The degree of decompression of the drying barrel may be appropriately selected, but it is preferable that the hydrous crumb can be efficiently dried when it is usually 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa.

The set temperature of the drying barrel may be appropriately selected, but when it is usually in the range of 100 to 250 ° C., preferably 110 to 200 ° C., more preferably 120 to 180 ° C., there is no discoloration or deterioration of the acrylic rubber. It is suitable because it can be dried efficiently and the amount of gel in the acrylic rubber veil can be reduced.

The number of drying barrels in the screw extruder is not limited, but is usually a plurality, preferably 2 to 10 barrels, more preferably 3 to 8 barrels. When there are a plurality of dry barrels, the degree of decompression may be an approximate degree of decompression for all the dry barrels, or may be changed for each barrel. When having a plurality of drying barrels, the set temperature may be an approximate temperature for all the drying barrels or may be changed for each barrel, but it is higher than the temperature of the crumb introduction part (closer to the dehydration barrel) on the upstream side. It is also preferable to raise the temperature of the discharge part (closer to the die) because the drying efficiency can be improved.

The water content of the dried rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. In the present invention, it is particularly preferable to set the water content of the dry rubber to this value (in a state where most of the water is removed) and melt-extrude it in a screw type extruder because the gel amount of the acrylic rubber veil can be reduced.

Acrylic rubber shape (die part)
The acrylic rubber dehydrated and dried by the dehydration barrel and the screw portion of the drying barrel of the screw type extruder is sent to a screwless rectifying die portion provided near the tip portion of the screw type extruder. A breaker plate or wire mesh may or may not be provided between the screw portion and the die portion.

The dry rubber extruded from the die portion of the screw type extruder is suitable because the die shape is made substantially rectangular and the dry rubber is extruded into a sheet shape, so that air entrainment is small, the specific gravity is large, and the dry rubber is excellent in storage stability. ..

The resin pressure in the die portion is not limited, but is usually 0.1 to 10 MPa, preferably 0.5 to 5 MPa, more preferably 1 to 3 MPa, and there is little air entrainment (high specific gravity). It has excellent productivity and is suitable.

Screw-type extruder and operating conditions The screw length (L) of the screw-type extruder used is appropriately selected according to the purpose of use, but is usually 3,000 to 15,000 mm, preferably 4,000 to 10, It is in the range of 000 mm, more preferably 4,500 to 8,000 mm.

The screw diameter (D) of the screw type extruder used is appropriately selected depending on the intended use, but is usually in the range of 50 to 250 mm, preferably 100 to 200 mm, and more preferably 120 to 160 mm. The ratio (L / D) of the screw length (L) to the screw diameter (D) of the screw type extruder used is not particularly limited, but is usually 10 to 100, preferably 20 to 80, and more preferably 30 to. When the range is 60, the water content can be reduced to less than 1% by weight without lowering the molecular weight of the dried rubber or causing discoloration, which is preferable.

The rotation speed (N) of the screw type extruder used is appropriately selected according to various conditions, but is usually 10 to 1,000 rpm, preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120. At ~ 300 rpm, the water content and gel amount of acrylic rubber can be efficiently reduced, which is preferable. The extrusion amount (Q) of the screw type extruder used is not particularly limited, but is usually 100 to 1,500 kg / hr, preferably 300 to 1,200 kg / hr, more preferably 400 to 1,000 kg / hr. Most preferably, it is in the range of 500 to 800 kg / hr. The ratio (Q / N) of the extrusion amount (Q) to the rotation speed (N) of the screw type extruder used is not particularly limited, but is usually 2 to 10, preferably 3 to 8, and more preferably 4 to 6. Is the range of.

Sheet-shaped dry rubber The shape of the dry rubber extruded from the screw-type extruder is sheet-like, and at this time, the specific gravity is large without entraining air, and the storage stability of the acrylic rubber veil can be highly improved, which is suitable. The sheet-like dry rubber extruded from the screw-type extruder is preferably used as an acrylic rubber sheet that has been cooled and cut to an appropriate size.

The thickness of the sheet-shaped dry rubber extruded from the screw type extruder is not particularly limited, but is usually in the range of 1 to 40 mm, preferably 2 to 35 mm, more preferably 3 to 30 mm, and most preferably 5 to 25 mm. It is suitable because it has excellent workability and productivity at some time. In particular, since the thermal conductivity of the sheet-shaped dry rubber is as low as 0.15 to 0.35 W / mK, the thickness of the sheet-shaped dry rubber is usually 1 to 30 mm when the cooling efficiency is increased and the productivity is remarkably improved. The range is preferably 2 to 25 mm, more preferably 3 to 15 mm, and particularly preferably 4 to 12 mm.

The width of the sheet-shaped dry rubber extruded from the screw type extruder may be appropriately selected according to the purpose of use, but is usually in the range of 300 to 1,200 mm, preferably 400 to 1,000 mm, and more preferably 500 to 800 mm. Is.

The temperature of the dry rubber extruded from the screw type extruder is not particularly limited, but is usually in the range of 100 to 200 ° C., preferably 110 to 180 ° C., and more preferably 120 to 160 ° C.

The water content of the dry rubber extruded from the screw type extruder is less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less.

The complex viscosity ([η] 100 ° C.) of the sheet-shaped dry rubber extruded from the screw type extruder at 100 ° C. is not particularly limited, but is usually 1,500 to 6,000 Pa · s, preferably 2,000 to 5 When the range is 3,000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s, the extrudability and shape retention as a sheet are highly high. Balanced and suitable. That is, when it is at least the above lower limit, the extrudability is improved, and when it is at least the upper limit, the shape of the sheet-shaped dry rubber can be suppressed from collapsing or breaking.

In the present invention, the sheet-shaped dry rubber extruded from the screw type extruder is suitable because when it is laminated and veiled after cutting, the amount of air entrained is small and the storage stability is excellent. The cutting method of the sheet-shaped dry rubber is not limited, but since the acrylic rubber sheet-shaped dry rubber has strong adhesiveness, it is preferable to cool the sheet-shaped dry rubber in order to cut it continuously without entraining air. .. The cutting temperature of the sheet-shaped dry rubber is not particularly limited, but is preferably 60 ° C. or lower, preferably 55 ° C. or lower, more preferably 50 ° C. or lower, because the cutability and productivity are highly balanced. Is.

The complex viscosity ([η] 60 ° C.) of the sheet-shaped dry rubber at 60 ° C. is not particularly limited, but is usually 15,000 Pa · s or less, preferably 2,000 to 10,000 Pa · s, more preferably 2,. When it is in the range of 500 to 7,000 Pa · s, most preferably 2,700 to 5,500 Pa · s, it is preferable that it can be cut continuously without entraining air.

The ratio of the complex viscosity at 100 ° C. ([η] 100 ° C.) to the complex viscosity at 60 ° C. ([η] 60 ° C.) ([η] 100 ° C./[η] 60 ° C.) of the sheet-shaped dry rubber is Although not particularly limited, air is usually in the range of 0.5 or more, preferably 0.5 to 0.98, more preferably 0.6 to 0.95, and most preferably 0.75 to 0.93. It is suitable because it has low entanglement and has a high balance between cutting and productivity.

The cooling method of the sheet-shaped dry rubber is not particularly limited and may be left at room temperature. However, since the thermal conductivity of the sheet-shaped dry rubber is very small, 0.15 to 0.35 W / mK, air is blown. Alternatively, forced cooling such as an air cooling method under cooling, a water spraying method in which water is sprayed, or a dipping method in which water is immersed is preferable in order to increase productivity, and an air cooling method in which air is blown or cooled is particularly preferable.

In the air-cooled method of sheet-shaped dry rubber, for example, the sheet-shaped dry rubber can be extruded from a screw-type extruder onto a conveyor such as a belt conveyor, and can be conveyed and cooled while blowing cold air. The temperature of the cold air is not limited, but is usually in the range of 0 to 25 ° C, preferably 5 to 25 ° C, and more preferably 10 to 20 ° C. The length to be cooled is not limited, but is usually in the range of 5 to 500 m, preferably 10 to 200 m, more preferably 20 to 100 m. The cooling rate of the sheet-shaped dry rubber is not limited, but is preferably 50 ° C./hr or higher, more preferably 100 ° C./hr or higher, more preferably 150 ° C./hr or higher, because cutting is particularly easy. is there.

The cutting length of the sheet-shaped dry rubber may be appropriately selected according to the size of the acrylic rubber veil to be manufactured, but is usually in the range of 100 to 800 mm, preferably 200 to 500 mm, and more preferably 250 to 450 mm.

(Veiling process)
The bale step in the method for producing an acrylic rubber veil of the present invention is to laminate the above sheet-shaped dry rubber to make a veil. The laminating temperature of the sheet-shaped dry rubber is not particularly limited, but is preferably 30 ° C. or higher, preferably 35 ° C. or higher, more preferably 40 ° C. or higher, because air entrained during laminating can escape. The number of layers may be appropriately selected according to the size or weight of the acrylic rubber veil.

The acrylic rubber veil of the present invention thus obtained has excellent operability and storage stability as compared with crumb-shaped acrylic rubber, and the acrylic rubber veil is put into a mixer such as a vanbury or roll as it is or after cutting a necessary amount. Can be used.

<Rubber mixture>
The rubber mixture of the present invention is characterized in that the acrylic rubber veil is mixed with a filler and a cross-linking agent.

The filler is not particularly limited, and examples thereof include a reinforcing filler and a non-reinforcing filler, and a reinforcing filler is preferable. Examples of the reinforcing filler include carbon black such as furnace black, acetylene black, thermal black, channel black, and graphite; silica such as wet silica, dry silica, and colloidal silica; and the like. Examples of the non-reinforcing filler include quartz powder, silica soil, zinc oxide, basic magnesium carbonate, active calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, and calcium sulfate. Examples include barium sulfate.

Each of these fillers can be used alone or in combination of two or more, and the blending amount thereof is not particularly limited, but is usually 1 to 200 parts by weight with respect to 100 parts by weight of the acrylic rubber veil. It is preferably in the range of 10 to 150 parts by weight, more preferably 20 to 100 parts by weight.

The cross-linking agent may be appropriately selected according to the type and application of the reactive group contained in the acrylic rubber constituting the acrylic rubber bale, but is not limited as long as it can cross-link the acrylic rubber bale. For example, polyvalent amine compounds such as diamine compounds and carbonates thereof; sulfur compounds; sulfur donors; triazinethiol compounds; polyvalent epoxy compounds; ammonium organic carboxylates; organic peroxides; polyvalent carboxylic acids; quaternary Conventionally known cross-linking agents such as onium salt; imidazole compound; isocyanuric acid compound; organic peroxide; triazine compound; can be used. Among these, polyvalent amine compounds, ammonium carboxylates, metal dithiocarbamic acid salts and triazinethiol compounds are preferable, hexamethylenediamine carbamate, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, and benzoate. Ammonium acid, 2,4,6-trimercapto-1,3,5-triazine is particularly preferred.

When the acrylic rubber veil to be used is composed of a carboxyl group-containing acrylic rubber, it is preferable to use a polyvalent amine compound and a carbonate thereof as a cross-linking agent. Examples of the polyvalent amine compound used here include aliphatic polyvalent amine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, and N, N'-dicinnamylidene-1,6-hexanediamine; 4,4'-methylenedi. Aniline, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-(m-phenylenediisopropyridene) dianiline, 4,4'-(p) -Phenylenediisopropyridene) dianiline, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, 4,4'-bis (4-aminophenoxy) biphenyl, Aromatic polyvalent amine compounds such as m-xylylenediamine, p-xylylenediamine, 1,3,5-benzenetriamine; and the like. Among these, hexamethylenediamine carbamate, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane and the like are preferable.

When the acrylic rubber veil to be used is composed of an epoxy group-containing acrylic rubber, the cross-linking agent is an aliphatic polyvalent amine compound such as hexamethylenediamine or hexamethylenediamine carbamate, and a carbonate thereof; 4,4'-methylene. Aromatic polyvalent amine compounds such as dianiline; ammonium carboxylic acid salts such as ammonium benzoate and ammonium adipate; metal dithiocarbamic acid salts such as zinc dimethyldithiocarbamate; polyvalent carboxylic acids such as tetradecanodic acid; cetyltrimethylammonium bromide Tertiary onium salts such as; imidazole compounds such as 2-methylimidazole; isocyanuric acid compounds such as ammonium isocyanurate; among these, ammonium carboxylic acid salt and metal dithiocarbamate salt are preferable, and ammonium benzoate is preferable. Is more preferable.

When the acrylic rubber veil to be used is composed of a halogen atom-containing acrylic rubber, it is preferable to use sulfur, a sulfur donor, or a triazine thiol compound as a cross-linking agent. Examples of the sulfur donor include dipentamethylene thiuram hexasulfide and triethyl thiuram disulfide. Examples of the triazine compound include 6-trimercapto-s-triazine, 2-anilino-4,6-dithiol-s-triazine, 1-dibutylamino-3,5-dimercaptotriazine, 2-dibutylamino-4, 6-Dithiol-s-Triazine, 1-Phenylamino-3,5-Dimercaptotriazine, 2,4,6-Trimercapto-1,3,5-Triazine, 1-Hexylamino-3,5-Dimercaptotriazine Among these, 2,4,6-trimercapto-1,3,5-triazine is preferable.

Each of these cross-linking agents can be used alone or in combination of two or more, and the blending amount thereof is usually 0.001 to 20 parts by weight, preferably 0.1 parts by weight, based on 100 parts by weight of the acrylic rubber veil. It is 10 parts by weight, more preferably 0.1 to 5 parts by weight. By setting the blending amount of the cross-linking agent within this range, it is possible to make the mechanical strength of the rubber cross-linked product excellent while making the rubber elasticity sufficient, which is preferable.

In the rubber mixture of the present invention, other rubber components other than the acrylic rubber veil can be used, if necessary. The other rubber components used here as needed are not particularly limited, and include, for example, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicon rubber, fluororubber, and the like. Examples thereof include olefin-based elastomers, styrene-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, and polysiloxane-based elastomers. The shape of the other rubber components is not limited, and may be, for example, a crumb shape, a sheet shape, a veil shape, or the like.

These other rubber components can be used alone or in combination of two or more. The amount of these other rubber components used is appropriately selected within a range that does not impair the effects of the present invention.

The rubber mixture of the present invention can be blended with an anti-aging agent, if necessary. The anti-aging agent is not particularly limited, but is 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylphenol, butylhydroxyanisole, 2,6-di-t-butyl-. α-Dimethylamino-p-cresol, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2,2'-methylene-bis (6-α-methyl-) Benzyl-p-cresol), 4,4'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 2,4-bis [(Octylthio) Methyl] -6-methylphenol, 2,2'-thiobis- (4-methyl-6-t-butylphenol), 4,4'-thiobis- (6-t-butyl-o-cresol), Other phenolic antioxidants such as 2,6-di-t-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine-2-ylamino) phenol; tris (nonylphenyl) Phenolic acid ester anti-aging agents such as phosphite, diphenylisodecylphosphite, tetraphenyldipropylene glycol diphosphite; sulfur ester anti-aging agents such as dilauryl thiodipropionate; phenyl-α-naphthylamine, phenyl-β- Naftylamine, p- (p-toluenesulfonylamide) -diphenylamine, 4,4'-(α, α-dimethylbenzyl) diphenylamine, N, N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p -Amine-based antioxidants such as phenylenediamine, butylaldehyde-aniline condensate; imidazole-based antioxidants such as 2-mercaptobenzimidazole; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin, etc. Kinolin-based anti-aging agents; hydroquinone-based anti-aging agents such as 2,5-di- (t-amyl) hydroquinone; and the like. Of these, amine-based anti-aging agents are particularly preferable.

These anti-aging agents can be used individually or in combination of two or more, and the blending amount thereof is 0.01 to 15 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the acrylic rubber veil. It is in the range of 10 parts by weight, more preferably 1 to 5 parts by weight.

The rubber mixture of the present invention contains the acrylic rubber veil of the present invention, a filler, a cross-linking agent and, if necessary, other rubber components and an anti-aging agent, and is usually used in the art as necessary. Other compounding agents, such as cross-linking aids, cross-linking accelerators, cross-linking retarders, silane coupling agents, plasticizers, processing aids, rubbers, pigments, colorants, antistatic agents, foaming agents, etc. it can. These other compounding agents can be used alone or in combination of two or more, and the compounding amount thereof is appropriately selected within a range that does not impair the effects of the present invention.

<Manufacturing method of rubber mixture>
As a method for producing a rubber mixture of the present invention, the acrylic rubber veil of the present invention is mixed with the above-mentioned filler, a cross-linking agent and the above-mentioned other rubber components, an anti-aging agent and other compounding agents which can be contained as needed. For the mixing, any means conventionally used in the rubber processing field, for example, an open roll, a Banbury mixer, various kneaders and the like can be used. That is, using these mixers, the acrylic rubber veil can be mixed by directly mixing the filler, the cross-linking agent and the like, preferably by directly kneading. In that case, the acrylic rubber bale may be used as it is or after being divided (cut or the like).

The mixing procedure of each component is not particularly limited, but for example, after sufficiently mixing the components that are difficult to react or decompose with heat, the reaction or decomposition occurs with a cross-linking agent that is a component that easily reacts or decomposes with heat. Two-step mixing is preferred, in which the mixture is mixed in a short time at no temperature. Specifically, it is preferable to mix the acrylic rubber veil and the filler in the first step and then mix the cross-linking agent in the second step. Other rubber components and anti-aging agents are usually mixed in the first stage, the cross-linking accelerator may be selected in the second stage, and other compounding agents may be appropriately selected.

The Mooney viscosity (ML1 + 4,100 ° C.; compound Mooney) of the rubber mixture of the present invention thus obtained is usually in the range of 10 to 150, preferably 20 to 100, and more preferably 25 to 80.

<Rubber crosslinked product>
The rubber crosslinked product of the present invention is obtained by cross-linking the above rubber mixture.
The rubber crosslinked product of the present invention is formed by using the rubber mixture of the present invention with a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and then heated to carry out a cross-linking reaction. It can be manufactured by fixing the shape as a rubber crosslinked product. In this case, cross-linking may be performed after molding in advance, or cross-linking may be performed at the same time as molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 150 ° C. The cross-linking temperature is usually 100 to 250 ° C., preferably 130 to 220 ° C., more preferably 150 to 200 ° C., and the cross-linking time is usually 0.1 minutes to 10 hours, preferably 1 minute to 5 hours. As the heating method, a method used for cross-linking rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

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

The crosslinked rubber product of the present invention has excellent water resistance while maintaining basic rubber properties such as tensile strength, elongation, and hardness.

The rubber crosslinked product of the present invention makes use of the above characteristics, for example, O-ring, packing, diaphragm, oil seal, shaft seal, bearing sheath, mechanical seal, well head seal, seal for electric / electronic equipment, air compression equipment. Sealing materials such as seals for seals; rocker cover gaskets attached to the connection between the cylinder block and the cylinder head, oil pan gaskets attached to the connection between the oil pan and the cylinder head or the transmission case, positive electrode, electrolyte plate and negative electrode. Various gaskets such as gaskets for fuel cell separators and gaskets for top covers of hard disk drives mounted between a pair of housings that sandwich a unit cell equipped with; cushioning material, anti-vibration material; wire coating material; industrial belts; tubes -Preferably used as hoses; sheets; etc.

The rubber cross-linked product of the present invention is also used as an extruded molded product and a molded cross-linked product for automobile applications, for example, fuel oil around a fuel tank such as a fuel hose, a filler neck hose, a vent hose, a paper hose, and an oil hose. It is suitably used for various hoses such as air hoses such as system hoses, turbo air hoses and mission control hoses, radiator hoses, heater hoses, brake hoses and air conditioner hoses.

<Device configuration used for manufacturing acrylic rubber veils>
Next, an apparatus configuration used for manufacturing an acrylic rubber veil according to an embodiment of the present invention will be described. FIG. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system having an apparatus configuration used for manufacturing an acrylic rubber veil according to an embodiment of the present invention. For the production of the acrylic rubber according to the present invention, for example, the acrylic rubber production system 1 shown in FIG. 1 can be used.

The acrylic rubber manufacturing system 1 shown in FIG. 1 is composed of an emulsion polymerization reactor (not shown), a coagulation device 3, a cleaning device 4, a drainer 43, a screw type extruder 5, a cooling device 6, and a bale device 7. ..

The emulsion polymerization reactor is configured to perform the treatment related to the emulsion polymerization step described above. Although not shown in FIG. 1, this emulsion polymerization reactor includes, for example, a polymerization reaction tank, a temperature control unit for controlling the reaction temperature, a motor, and a stirring device including a stirring blade. In the emulsion polymerization reactor, water and a sodium sulfate ester as an emulsifier are mixed with a monomer component for forming acrylic rubber and emulsified while being appropriately stirred with a stirrer, and emulsion polymerization is carried out in the presence of a polymerization catalyst. By doing so, an emulsion polymerization solution can be obtained. The emulsion polymerization reactor may be a batch type, a semi-batch type, or a continuous type, and may be any of a tank type reactor and a tube type reactor.

The coagulation device 3 shown in FIG. 1 is configured to perform the process related to the coagulation step described above. As schematically shown in FIG. 1, the coagulation device 3 includes, for example, a stirring tank 30, a heating unit 31 for heating the inside of the stirring tank 30, and a temperature control unit (not shown) for controlling the temperature inside the stirring tank 30. It has a stirring device 34 including a motor 32 and a stirring blade 33, and a drive control unit (not shown) that controls the rotation speed and rotation speed of the stirring blade 33. In the coagulation apparatus 3, a hydrous crumb can be produced by bringing the emulsion polymerization solution obtained by the emulsion polymerization reactor into contact with the coagulation solution as a coagulant and coagulating it.

In the coagulation device 3, for example, a method of adding the emulsion polymerization solution to the stirring magnesium salt aqueous solution is adopted for the contact between the emulsion polymerization solution and the coagulation solution. That is, a water-containing crumb is generated by filling the stirring tank 30 of the coagulation device 3 with a coagulation liquid and adding and contacting the emulsion polymerization liquid with the coagulation liquid to coagulate the emulsion polymerization liquid.

The heating unit 31 of the coagulation device 3 is configured to heat the coagulation liquid filled in the stirring tank 30. Further, the temperature control unit of the coagulation device 3 controls the temperature inside the stirring tank 30 by controlling the heating operation by the heating unit 31 while monitoring the temperature inside the stirring tank 30 measured by the thermometer. It is configured. The temperature of the coagulating liquid in the stirring tank 30 is controlled by the temperature control unit so as to be usually in the range of 40 ° C. or higher, preferably 40 to 90 ° C., and more preferably 50 to 80 ° C.

The stirring device 34 of the coagulating device 3 is configured to stir the coagulating liquid filled in the stirring tank 30. Specifically, the stirring device 34 includes a motor 32 that generates rotational power and a stirring blade 33 that extends in a direction perpendicular to the rotation axis of the motor 32. The stirring blade 33 can flow the coagulating liquid by rotating around the rotation axis by the rotational power of the motor 32 in the coagulating liquid filled in the stirring tank 30. The shape and size of the stirring blade 33, the number of installations, and the like are not particularly limited.

The drive control unit of the solidifying device 3 is configured to control the rotational drive of the motor 32 of the stirring device 34 to set the rotation speed and the rotation speed of the stirring blade 33 of the stirring device 34 to predetermined values. The rotation of the stirring blade 33 is controlled by the drive control unit so that the stirring number of the coagulating liquid is, for example, usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm, and particularly preferably 400 to 800 rpm. Will be done. The peripheral speed of the coagulant is usually 0.5 m / s or more, preferably 1 m / s or more, more preferably 1.5 m / s or more, particularly preferably 2 m / s or more, and most preferably 2.5 m / s or more. The rotation of the stirring blade 33 is controlled by the drive control unit. Further, the drive control unit agitates the coagulant so that the upper limit of the peripheral speed is usually 50 m / s or less, preferably 30 m / s or less, more preferably 25 m / s or less, and most preferably 20 m / s or less. The rotation of the wing 33 is controlled.

The cleaning device 4 shown in FIG. 1 is configured to perform the processing related to the cleaning step described above. As schematically shown in FIG. 1, the cleaning device 4 includes, for example, a cleaning tank 40, a heating unit 41 that heats the inside of the cleaning tank 40, and a temperature control unit (not shown) that controls the temperature inside the cleaning tank 40. Have. In the cleaning device 4, the amount of ash in the finally obtained acrylic rubber veil can be effectively reduced by mixing the water-containing crumb generated by the coagulation device 3 with a large amount of water and cleaning.

The heating unit 41 of the cleaning device 4 is configured to heat the inside of the cleaning tank 40. Further, the temperature control unit of the cleaning device 4 controls the temperature inside the cleaning tank 40 by controlling the heating operation by the heating unit 41 while monitoring the temperature inside the cleaning tank 40 measured by the thermometer. It is configured. As described above, the temperature of the washing water in the washing tank 40 is usually controlled to be in the range of 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C., and most preferably 60 to 80 ° C. To.

The water-containing crumb washed by the washing device 4 is supplied to the screw type extruder 5 that performs the dehydration step and the drying step. At this time, it is preferable that the water-containing crumb after cleaning is supplied to the screw type extruder 5 through a drainer 43 capable of separating free water. For the drainer 43, for example, a wire mesh, a screen, an electric sieve, or the like can be used.

Further, when the water-containing crumb after cleaning is supplied to the screw type extruder 5, the temperature of the water-containing crumb is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. For example, by setting the temperature of the water used for washing in the washing device 4 to 60 ° C. or higher (for example, 70 ° C.), the temperature of the water-containing crumb when supplied to the screw type extruder 5 is maintained at 60 ° C. or higher. The temperature of the hydrous crumb may be 40 ° C. or higher, preferably 60 ° C. or higher when it is conveyed from the cleaning device 4 to the screw type extruder 5. As a result, the dehydration step and the drying step, which are the subsequent steps, can be effectively performed, and the water content of the finally obtained dried rubber can be significantly reduced.

The screw type extruder 5 shown in FIG. 1 is configured to perform the processes related to the above-mentioned dehydration step and drying step. Although the screw type extruder 5 is shown as a suitable example in FIG. 1, a centrifuge, a squeezer, or the like may be used as the dehydrator for performing the treatment related to the dehydration step. A hot air dryer, a vacuum dryer, an expander dryer, a kneader type dryer, or the like may be used as the dryer.

The screw type extruder 5 is configured to mold the dried rubber obtained through the dehydration step and the drying step into a predetermined shape and discharge it. Specifically, the screw type extruder 5 has a dehydration barrel portion 53 having a function as a dehydrator for dehydrating the hydrous crumb washed by the cleaning device 4, and a drying machine having a function as a dryer for drying the hydrous crumb. A barrel portion 54 is provided, and a die 59 having a molding function for forming a water-containing crumb is provided on the downstream side of the screw type extruder 5.

Hereinafter, the configuration of the screw type extruder 5 will be described with reference to FIG. FIG. 2 shows a configuration of a specific example suitable for the screw type extruder 5 shown in FIG. With this screw type extruder 5, the above-mentioned dehydration / drying step can be suitably performed.

The screw type extruder 5 shown in FIG. 2 is a biaxial screw type extruder / dryer provided with a pair of screws (not shown) in the barrel unit 51. The screw type extruder 5 has a drive unit 50 that rotationally drives a pair of screws in the barrel unit 51. The drive unit 50 is attached to the upstream end (left end in FIG. 2) of the barrel unit 51. Further, the screw type extruder 5 has a die 59 at the downstream end (right end in FIG. 2) of the barrel unit 51.

The barrel unit 51 has a supply barrel portion 52, a dehydration barrel portion 53, and a dry barrel portion 54 from the upstream side to the downstream side (from the left side to the right side in FIG. 2).

The supply barrel portion 52 is composed of two supply barrels, that is, a first supply barrel 52a and a second supply barrel 52b.

Further, the dehydration barrel portion 53 is composed of three dehydration barrels, that is, a first dehydration barrel 53a, a second dehydration barrel 53b, and a third dehydration barrel 53c.

Further, the drying barrel portion 54 includes eight drying barrels, that is, a first drying barrel 54a, a second drying barrel 54b, a third drying barrel 54c, a fourth drying barrel 54d, and a fifth drying barrel 54e. , A sixth dry barrel 54f, a seventh dry barrel 54g, and an eighth dry barrel 54h.

As described above, the barrel unit 51 is configured by connecting the 13 divided barrels 52a to 52b, 53a to 53c, 54a to 54h from the upstream side to the downstream side.

Further, the screw type extruder 5 individually heats the barrels 52a to 52b, 53a to 53c, 54a to 54h, and determines the water content crumbs in the barrels 52a to 52b, 53a to 53c, 54a to 54h, respectively. It has a heating means (not shown) for heating to a temperature. The heating means includes a number corresponding to each barrel 52a to 52b, 53a to 53c, 54a to 54h. As such a heating means, for example, a configuration is adopted in which high-temperature steam is supplied from the steam supply means to the steam distribution jackets formed in the barrels 52a to 52b, 53a to 53c, 54a to 54h. It is not limited to this. Further, the screw type extruder 5 has a temperature control means (not shown) that controls a set temperature of each heating means corresponding to each barrel 52a to 52b, 53a to 53c, 54a to 54h.

The number of supply barrels, dehydration barrels, and drying barrels that constitute each barrel portion 52, 53, 54 in the barrel unit 51 is not limited to the mode shown in FIG. 2, and the acrylic rubber to be dried is used. The number can be set according to the water content of the water-containing crumb.

For example, the number of supply barrels installed in the supply barrel portion 52 is, for example, 1 to 3. The number of dehydration barrels installed in the dehydration barrel portion 53 is preferably, for example, 2 to 10, and more preferably 3 to 6, because dehydration of the water-containing crumb of the adhesive acrylic rubber can be efficiently performed. Further, the number of dry barrels installed in the dry barrel portion 54 is preferably, for example, 2 to 10, and more preferably 3 to 8.

The pair of screws in the barrel unit 51 are rotationally driven by a driving means such as a motor housed in the driving unit 50. The pair of screws extend from the upstream side to the downstream side in the barrel unit 51, and by being rotationally driven, the water-containing crumbs supplied to the supply barrel portion 52 can be conveyed to the downstream side while being mixed. It has become like. The pair of screws is preferably a biaxial meshing type in which the peaks and valleys are meshed with each other, whereby the dehydration efficiency and the drying efficiency of the hydrous crumb can be improved.

Further, the rotation direction of the pair of screws may be the same direction or different directions, but from the viewpoint of self-cleaning performance, a type that rotates in the same direction is preferable. The screw shape of the pair of screws is not particularly limited as long as it is a shape required for each of the barrel portions 52, 53, 54, and is not particularly limited.

The supply barrel portion 52 is a region for supplying the water-containing crumb into the barrel unit 51. The first supply barrel 52a of the supply barrel portion 52 has a feed port 55 for supplying a water-containing crumb in the barrel unit 51.

The dehydration barrel portion 53 is a region for separating and discharging a liquid (serum water) containing a coagulant or the like from the hydrous crumb.

The first to third dehydration barrels 53a to 53c constituting the dehydration barrel portion 53 have dehydration slits 56a, 56b, and 56c for discharging the water content of the hydrous crumb to the outside, respectively. A plurality of the dehydration slits 56a, 56b, 56c are formed in the dehydration barrels 53a to 53c, respectively.

The slit widths, that is, the openings of the dehydration slits 56a, 56b, and 56c may be appropriately selected according to the usage conditions, and are usually 0.01 to 5 mm, so that the water-containing crumbs are less damaged and the water-containing crumbs have little loss. From the viewpoint of efficient dehydration, it is preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm.

There are two ways to remove water from the water-containing crumbs in each of the dehydration barrels 53a to 53c of the dehydration barrel portion 53: a liquid removal from the dehydration slits 56a, 56b, 56c, and a vapor removal. .. In the dehydration barrel portion 53 of the present embodiment, the case where water is removed in liquid form is defined as wastewater, and the case where water is removed in vapor form is defined as exhaust steam.

The dehydration barrel portion 53 is suitable because the water content of the adhesive acrylic rubber can be efficiently reduced by combining drainage and exhaust steam. In the dehydration barrel portion 53, which of the first to third dehydration barrels 53a to 53c is used for drainage or exhaust steam may be appropriately set according to the purpose of use, but is usually manufactured. When reducing the amount of ash in the acrylic rubber, it is advisable to increase the number of dehydration barrels for draining. In that case, for example, as shown in FIG. 2, drainage is performed in the first and second dehydration barrels 53a and 53b on the upstream side, and steam is discharged in the third dehydration barrel 53c on the downstream side. Further, for example, when the dehydration barrel portion 53 has four dehydration barrels, for example, drainage may be performed by three dehydration barrels on the upstream side, and steam may be exhausted by one dehydration barrel on the downstream side. On the other hand, when reducing the water content, it is preferable to increase the number of dehydration barrels for exhausting steam.

As described in the above-mentioned dehydration / drying step, the set temperature of the dehydration barrel portion 53 is usually in the range of 60 to 150 ° C., preferably 70 to 140 ° C., more preferably 80 to 130 ° C., and is dehydrated in the drained state. The set temperature of the dehydration barrel to be dehydrated is usually 60 ° C. to 120 ° C., preferably 70 to 110 ° C., more preferably 80 to 100 ° C., and the set temperature of the dehydration barrel to be dehydrated in the exhausted steam state is usually 100 to 150 ° C. The temperature is preferably in the range of 105 to 140 ° C, more preferably 110 to 130 ° C.

The drying barrel portion 54 is a region for drying the hydrous crumb after dehydration under reduced pressure. Of the first to eighth dry barrels 54a to 54h constituting the dry barrel portion 54, the second dry barrel 54b, the fourth dry barrel 54d, the sixth dry barrel 54f, and the eighth dry barrel 54h are It has vent ports 58a, 58b, 58c, and 58d for degassing, respectively. Vent pipes (not shown) are connected to the vent ports 58a, 58b, 58c, and 58d, respectively.

Vacuum pumps (not shown) are connected to the ends of the vent pipes, and the operation of the vacuum pumps reduces the pressure inside the drying barrel portion 54 to a predetermined pressure. The screw type extruder 5 has a pressure control means (not shown) that controls the operation of these vacuum pumps to control the degree of decompression in the drying barrel portion 54.

The degree of decompression in the dry barrel portion 54 may be appropriately selected, but as described above, it is usually set to 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa.

The set temperature in the drying barrel portion 54 may be appropriately selected, but as described above, it is usually set to 100 to 250 ° C., preferably 110 to 200 ° C., and more preferably 120 to 180 ° C.

In each of the dry barrels 54a to 54h constituting the dry barrel portion 54, the set temperatures in all the dry barrels 54a to 54h may be approximated or different, but on the upstream side (dehydrated barrel portion). It is preferable to set the temperature on the downstream side (die 59 side) to a higher temperature than the temperature on the downstream side (53 side) because the drying efficiency is improved.

The die 59 is a mold arranged at the downstream end of the barrel unit 51, and has a discharge port having a predetermined nozzle shape. The acrylic rubber dried by the drying barrel portion 54 is extruded into a shape corresponding to a predetermined nozzle shape by passing through the discharge port of the die 59. The acrylic rubber that passes through the die 59 is formed into various shapes such as granular, columnar, round bar, and sheet depending on the nozzle shape of the die 59. For example, by making the discharge port of the die 59 substantially rectangular, the acrylic rubber can be extruded into a sheet shape. A breaker plate or wire mesh may or may not be provided between the screw and the die 59.

According to the screw type extruder 5 according to the present embodiment, the water-containing crumb of the raw material acrylic rubber is extruded into a sheet-shaped dry rubber as follows.

The water-containing crumb of acrylic rubber obtained through the cleaning step is supplied from the feed port 55 to the supply barrel portion 52. The water-containing crumb supplied to the supply barrel portion 52 is sent from the supply barrel portion 52 to the dehydration barrel portion 53 by the rotation of the pair of screws in the barrel unit 51. In the dehydration barrel portion 53, as described above, the water contained in the water-containing crumb is drained and exhausted from the dehydration slits 56a, 56b, 56c provided in the first to third dehydration barrels 53a to 53c, respectively. , The hydrous crumb is dehydrated.

The water-containing crumb dehydrated by the dehydration barrel portion 53 is sent to the dry barrel portion 54 by the rotation of a pair of screws in the barrel unit 51. The hydrous crumb sent to the dry barrel portion 54 is plasticized and mixed to form a melt, which generates heat and is carried to the downstream side while raising the temperature. Then, the water contained in the melt of the acrylic rubber is vaporized, and the water (steam) is discharged to the outside through vent pipes (not shown) connected to the vent ports 58a, 58b, 58c, and 58d, respectively.

By passing through the dry barrel portion 54 as described above, the hydrous crumb is dried and becomes a melt of acrylic rubber, and the acrylic rubber is supplied to the die 59 by the rotation of a pair of screws in the barrel unit 51 to form a sheet. It is extruded from the die 59 as a dry rubber.

Here, an example of the operating conditions of the screw type extruder 5 according to the present embodiment will be given.

The rotation speed (N) of the pair of screws in the barrel unit 51 may be appropriately selected according to various conditions, and is usually 10 to 1000 rpm, and the water content and gel amount of the acrylic rubber veil can be efficiently reduced. From the point of view, it is preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120 to 300 rpm.

The extrusion amount (Q) of acrylic rubber is not particularly limited, but is usually 100 to 1500 kg / hr, preferably 300 to 1200 kg / hr, more preferably 400 to 1000 kg / hr, and 500 to 800 kg / hr. hr is most preferred.

The ratio (Q / N) of the extrusion amount (Q) of the acrylic rubber to the rotation speed (N) of the screw is not particularly limited, but is usually 1 to 20, preferably 2 to 10, and more preferably. It is 3 to 8, and 4 to 6 is particularly preferable.

The cooling device 6 shown in FIG. 1 is configured to cool the dried rubber obtained through the dehydration step by the dehydrator and the drying step by the dryer. As the cooling method by the cooling device 6, various methods including an air cooling method by blowing air or cooling, a watering method of spraying water, a dipping method of immersing in water, and the like can be adopted. Further, the dried rubber may be cooled by leaving it at room temperature.

As described above, the dried rubber discharged from the screw type extruder 5 is extruded into various shapes such as granular, columnar, round bar, and sheet according to the nozzle shape of the die 59. Hereinafter, as an example of the cooling device 6, the transport type cooling device 60 for cooling the sheet-shaped dry rubber 10 formed into a sheet shape will be described with reference to FIG.

FIG. 3 shows the configuration of a transport type cooling device 60 suitable as the cooling device 6 shown in FIG. The transport type cooling device 60 shown in FIG. 3 is configured to cool the sheet-shaped dry rubber 10 discharged from the discharge port of the die 59 of the screw type extruder 5 by an air cooling method while transporting the sheet-shaped dry rubber 10. By using this transport type cooling device 60, the sheet-shaped dry rubber discharged from the screw type extruder 5 can be suitably cooled.

The transport type cooling device 60 shown in FIG. 3 is used, for example, directly connected to the die 59 of the screw type extruder 5 shown in FIG. 2 or installed in the vicinity of the die 59.

The transport-type cooling device 60 sends cold air to the conveyor 61 that conveys the sheet-shaped dry rubber 10 discharged from the die 59 of the screw-type extruder 5 in the direction of arrow A in FIG. 3 and the sheet-shaped dry rubber 10 on the conveyor 61. It has a cooling means 65 for spraying.

The conveyor 61 has rollers 62 and 63, and a conveyor belt 64 that is wound around the rollers 62 and 63 and on which the sheet-shaped dry rubber 10 is placed. The conveyor 61 is configured to continuously convey the sheet-shaped dry rubber 10 discharged from the die 59 of the screw type extruder 5 to the downstream side (right side in FIG. 3) on the conveyor belt 64.

The cooling means 65 is not particularly limited, but has, for example, a structure capable of blowing the cooling air sent from the cooling air generating means (not shown) onto the surface of the sheet-shaped dry rubber 10 on the conveyor belt 64. And so on.

The length (length of the portion where the cooling air can be blown) L1 of the conveyor 61 and the cooling means 65 of the transport type cooling device 60 is not particularly limited, but is, for example, 10 to 100 m, preferably 20 to 50 m. .. Further, the transport speed of the sheet-shaped dry rubber 10 in the transport-type cooling device 60 is the length L1 of the conveyor 61 and the cooling means 65, the discharge speed of the sheet-shaped dry rubber 10 discharged from the die 59 of the screw type extruder 5. It may be appropriately adjusted according to the target cooling rate, cooling time, etc., but is, for example, 10 to 100 m / hr, more preferably 15 to 70 m / hr.

According to the transport type cooling device 60 shown in FIG. 3, the sheet-shaped dry rubber 10 discharged from the die 59 of the screw type extruder 5 is conveyed by the conveyor 61, and the sheet-shaped dry rubber 10 is transported from the cooling means 65. The sheet-shaped dry rubber 10 is cooled by blowing cooling air.

The transport type cooling device 60 is not particularly limited to a configuration including one conveyor 61 and one cooling means 65 as shown in FIG. 3, and two or more conveyors 61 and two or more corresponding conveyors 61. It may be configured to include the cooling means 65 of the above. In that case, the total length of each of the two or more conveyors 61 and the cooling means 65 may be within the above range.

The bale device 7 shown in FIG. 1 is configured to extrude from a screw type extruder 5 and further process a dry rubber cooled by the cooling device 6 to produce a bale which is a block. As described above, the screw type extruder 5 can extrude the dried rubber into various shapes such as granular, columnar, round bar, and sheet, and the bale device 7 has various shapes as described above. It is configured to veil dry rubber molded into a shape. The weight and shape of the acrylic rubber bale produced by the bale-forming device 7 are not particularly limited, but for example, an acrylic rubber bale having a substantially rectangular parallelepiped shape of about 20 kg is produced.

The bale device 7 may include, for example, a baler, and may manufacture an acrylic rubber bale by compressing the cooled dry rubber with the baler.

Further, when the sheet-shaped dry rubber 10 is manufactured by the screw type extruder 5, an acrylic rubber veil in which the sheet-shaped dry rubber 10 is laminated may be manufactured. For example, the bale-forming device 7 arranged on the downstream side of the transport-type cooling device 60 shown in FIG. 3 may be provided with a cutting mechanism for cutting the sheet-shaped dry rubber 10. Specifically, the cutting mechanism of the bale device 7 continuously cuts the cooled sheet-shaped dry rubber 10 at predetermined intervals and processes it into a cut sheet-shaped dry rubber 16 having a predetermined size. It is configured as follows. By laminating a plurality of cut sheet-shaped dry rubbers 16 cut to a predetermined size by a cutting mechanism, an acrylic rubber veil in which the cut-sheet-shaped dry rubbers 16 are laminated can be manufactured.

When producing an acrylic rubber veil on which the cut sheet-shaped dry rubber 16 is laminated, it is preferable to laminate the cut sheet-shaped dry rubber 16 at 40 ° C. or higher, for example. By laminating the cut sheet-shaped dry rubber 16 at 40 ° C. or higher, good air release is realized by further cooling and compression by its own weight.

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

[Monomer composition]
Regarding the monomer composition in acrylic rubber, the monomer composition of each monomer unit in acrylic rubber was confirmed by 1 H-NMR, and the activity of the reactive group remained in acrylic rubber and each reaction thereof. The sex group content was confirmed by the following test method. The content ratio of each monomer unit in the acrylic rubber was calculated from the amount used in the polymerization reaction of each monomer and the polymerization conversion rate. Specifically, since the polymerization reaction was an emulsion polymerization reaction and the polymerization conversion rate was approximately 100% in which none of the unreacted monomers could be confirmed, the content ratio of each monomer unit was set to a single amount. It was the same as the amount used by the body.

[Reactive group content]
The content of the reactive group of the acrylic rubber was measured as the content in the acrylic rubber veil by the following method.
(1) The amount of carboxyl groups was calculated by dissolving an acrylic rubber veil in acetone and performing potentiometric titration with a potassium hydroxide solution.
(2) The amount of epoxy group was calculated by dissolving an acrylic rubber veil in methyl ethyl ketone, adding a specified amount of hydrochloric acid to the mixture to react with the epoxy group, and titrating the remaining amount of hydrochloric acid with potassium hydroxide.
(3) The amount of chlorine was calculated by completely burning an acrylic rubber veil in a combustion flask, absorbing the generated chlorine in water, and titrating with silver nitrate.

[Ash content]
The amount of ash (%) contained in the acrylic rubber veil was measured according to the JIS K6228 A method.

[Amount of ash component]
The amount of each component (ppm) in the acrylic rubber veil ash content was measured by XRF using ZSX Primus (manufactured by Rigaku) by pressing the collected ash content onto a Φ20 mm titration filter paper in the difference in the above ash content measurement.

[Gel amount]
The gel amount (%) of the acrylic rubber veil was the amount of the insoluble matter in methyl ethyl ketone, and was determined by the following method.
About 0.2 g of acrylic rubber veil is weighed (Xg), immersed in 100 ml methyl ethyl ketone, left at room temperature for 24 hours, and then dissolved in a filtrate obtained by filtering out the insoluble matter in methyl ethyl ketone using an 80 mesh wire mesh, that is, methyl ethyl ketone. The dry solid content (Yg) obtained by evaporating and solidifying the filtrate in which only the rubber component was dissolved was weighed and calculated by the following formula.
Gel amount (%) = 100 × (XY) / X

[specific gravity]
The specific gravity of the acrylic rubber veil was measured according to the method A of JIS K6268 crosslinked rubber-density measurement.

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) of acrylic rubber was measured using a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi High-Tech Science Co., Ltd.).

[PH]
The pH of the acrylic rubber veil was measured with a pH electrode after confirming that 6 g (± 0.05 g) of the acrylic rubber veil was dissolved in 100 g of tetrahydrofuran, and 2.0 ml of distilled water was added to completely dissolve the acrylic rubber veil.

[Water content]
The water content (%) of the acrylic rubber veil was measured according to the JIS K6230-1: Oven A (volatile content measurement) method.

[Molecular weight and molecular weight distribution]
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn and Mz / Mw) of the acrylic rubber are as follows: dimethylformamide as a solvent, lithium chloride at a concentration of 0.05 mol / L, and 37% concentrated hydrochloric acid at a concentration of 0.01%, respectively. It is an absolute molecular weight and an absolute molecular weight distribution measured by the GPC-MALS method using the added solution. Specifically, a multi-angle laser light scattering photometric meter (MALS) and a differential refractometer (RI) are incorporated into a GPC (Gel Permeation Chromatography) device, and the light scattering intensity and refraction of the molecular chain solution size-sorted by the GPC device are incorporated. The molecular weight of the solute and its content were sequentially calculated and obtained by measuring the rate difference with the elution time. The measurement conditions and measurement method by the GPC device are as follows.
Column: 2 TSKgel α-M (φ7.8 mm x 30 cm, manufactured by Tosoh Corporation)
Temperature: Column 40 ° C
Flow velocity: 0.8 ml / mm
Sample preparation: 5 ml of solvent was added to 10 mg of sample, and the mixture was gently stirred at room temperature (dissolution was visually observed). Then, filtration was performed using a 0.5 μm filter.
Injection volume: 0.200 ml

[Complex viscosity]
The complex viscosity η of the acrylic rubber bale is subjected to temperature dispersion (40 to 120 ° C.) at a strain of 473% and 1 Hz using a dynamic viscoelasticity measuring device “Rubber Process Analyzer RPA-2000” (manufactured by Alpha Technology). The measurement was performed to determine the complex viscoelasticity η at each temperature. Here, among the above-mentioned dynamic viscoelasticities, the dynamic viscoelasticity at 60 ° C. is defined as the complex viscoelasticity η (60 ° C.), and the dynamic viscoelasticity at 100 ° C. is defined as the complex viscoelasticity η (100 ° C.). The values of ° C.) / η (60 ° C.) and η (60 ° C.) / η (100 ° C.) were calculated.

[Moony Viscosity (ML1 + 4,100 ° C)]
The Mooney viscosity (ML1 + 4,100 ° C.) of the acrylic rubber sheet or acrylic rubber bale was measured according to the uncrosslinked rubber physical test method of JIS K6300.

[Evaluation of workability]
Regarding the processability of the rubber sample, the rubber sample was put into a Banbury mixer heated to 50 ° C., kneaded for 1 minute, and then the compounding agent A containing the rubber mixture shown in Table 1 was added to obtain the rubber mixture in the first stage. The time required for integration to show the maximum torque value, that is, BIT (Black Incorporation Time) was measured and evaluated with an index of Comparative Example 1 as 100 (the smaller the index, the better the workability).

[Storing stability evaluation]
For storage stability of the rubber sample, the rubber sample is placed in a constant temperature and humidity chamber (SH-222 manufactured by ESPEC) at 45 ° C. × 80% RH and stored for 7 days, and the rubber sample is processable before and after being placed in the constant temperature and humidity chamber. (BIT) was measured, the rate of change in BIT before and after charging into the constant temperature and humidity chamber was calculated, and evaluation was performed using an index with Comparative Example 1 as 100 (the smaller the index, the better the storage stability).

[Water resistance evaluation]
The water resistance of the rubber sample is determined by immersing the crosslinked product of the rubber sample in distilled water at a temperature of 85 ° C. for 100 hours in accordance with JIS K6258 for a dipping test, and calculating the volume change rate before and after dipping according to the following formula. It was evaluated by an index with 1 as 100 (the smaller the index, the better the water resistance).
Volume change rate before and after immersion (%) = ((volume of test piece after immersion-volume of test piece before immersion) / volume of test piece before immersion) × 100

[Example 1]
In a mixing container equipped with a homomixer, 46 parts of pure water, 48.5 parts of ethyl acrylate, 29 parts of n-butyl acrylate, 21 parts of methoxyethyl acrylate, 1.5 parts of vinyl chloroacetate, and lauryl sulfate as an emulsifier. 0.709 parts of sodium and 1.82 parts of polyoxyethylene dodecyl ether (molecular weight 1500) were charged and stirred to obtain a monomer emulsion.

Next, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were put into a polymerization reaction tank equipped with a thermometer and a stirrer, and cooled to 12 ° C. under a nitrogen stream. Next, the balance of the monomer emulsion, 0.00033 parts of ferrous sulfate, 0.264 parts of sodium ascorbate and 0.22 parts of potassium persulfate were continuously added dropwise to the polymerization reaction tank over 3 hours. After that, the reaction was continued while the temperature in the polymerization reaction tank was kept at 23 ° C., it was confirmed that the polymerization conversion rate reached approximately 100%, and hydroquinone as a polymerization terminator was added to carry out the polymerization reaction. It was stopped to obtain an emulsion polymerization solution.

In a coagulation tank equipped with a thermometer and a stirrer, the above-mentioned emulsion was obtained in a 2% sodium sulfate aqueous solution (coagulant) heated to 80 ° C. and vigorously stirred (600 rpm: peripheral speed 3.1 m / s). The polymer solution was heated to 80 ° C. and continuously added to solidify the polymer and filtered off to obtain a hydrous crumb.

Next, 194 parts of warm water (70 ° C.) was added to the coagulation tank and stirred for 15 minutes to drain water, and 194 parts of warm water (70 ° C.) was added again and stirred for 15 minutes to wash the water-containing crumb. Was done. The washed hydrous crumb is supplied to a screw type extruder, dehydrated and dried, and a sheet-shaped dry rubber having a width of 300 mm and a thickness of 10 mm is extruded, and a transfer type cooling device provided directly connected to the screw type extruder is used. , The sheet-shaped dry rubber was cooled at a cooling rate of 200 ° C./hr.

The screw type extruder used in the first embodiment has one supply barrel, three dehydration barrels (first to third dehydration barrels), and five drying barrels (first to fifth drying barrels). It is configured. The first and second dehydration barrels are designed to drain water, and the third dehydration barrel is designed to drain steam. The operating conditions of the screw type extruder are as follows.

Moisture content:
Moisture content of the hydrous crumb after drainage in the second dehydration barrel: 20%
Moisture content of the hydrous crumb after steam exhaust in the third dehydration barrel: 10%
Rubber temperature:
-The temperature of the hydrous crumb supplied to the first supply barrel: 65 ° C.
・ Temperature of rubber discharged from screw type extruder: 140 ℃
Set temperature of each barrel:
-First dehydration barrel: 90 ° C
-Second dehydration barrel: 100 ° C
-Third dehydration barrel: 120 ° C
-First drying barrel: 120 ° C
-Second drying barrel: 130 ° C
-Third drying barrel: 140 ° C
・ Fourth drying barrel: 160 ° C
・ Fifth drying barrel: 180 ° C
Operating conditions:
-Screw diameter (D) in the barrel unit: 132 mm
-Overall length (L) of the screw in the barrel unit: 4620 mm
・ L / D: 35
・ Screw rotation speed in the barrel unit: 135 rpm
-Rubber extrusion amount from die: 700 kg / hr
・ Die resin pressure: 2MPa

The sheet-shaped dry rubber extruded from the screw type extruder is cooled to 50 ° C, cut with a cutter, and laminated to 20 parts (20 kg) before the temperature drops below 40 ° C, and the acrylic rubber veil (A). ) Was obtained. Reactive group content, ash content, ash component content, specific gravity, gel amount, glass transition temperature (Tg), pH, water content, molecular weight, molecular weight distribution, complex viscosity and Mooney of the obtained acrylic rubber veil (A) The viscosity (ML1 + 4,100 ° C.) was measured and shown in Table 2. The value of "water content (%) after dehydration (drainage)" shown in the dehydration process column of Table 2 is the water content of the water content crumb immediately after drainage by the drainage type dehydration barrel (immediately before the exhaust steam type dehydration barrel). ..

Next, using a Bunbury mixer, 100 parts of the acrylic rubber veil (A) and the compounding agent A of "Formulation 1" shown in Table 1 were added and mixed at 50 ° C. for 5 minutes. At this time, the storage stability of the acrylic rubber veil (A) was evaluated, and the processability was further evaluated, and the results are shown in Table 2. Then, the obtained mixture was transferred to a roll at 50 ° C., and the compounding agent B of "Formulation 1" was mixed and mixed to obtain a rubber mixture.

The obtained rubber mixture was placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and was first crosslinked by pressing at 180 ° C. for 10 minutes while pressurizing at a press pressure of 10 MPa, and then the obtained primary was obtained. The crosslinked product was further heated in a gear oven at 180 ° C. for 2 hours for secondary cross-linking to obtain a sheet-shaped rubber crosslinked product. Then, a 3 cm × 2 cm × 0.2 cm test piece was cut out from the obtained sheet-shaped rubber crosslinked product to perform a water resistance test, and the results are shown in Table 2.

[Example 2]
The monomer component was changed to 98.5 parts of ethyl acrylate and 1.5 parts of vinyl chloroacetate, and the temperature of the first dehydration barrel of the screw type extruder was set to 100 ° C. and the temperature of the second dehydration barrel was set to 120. Acrylic rubber veil was carried out in the same manner as in Example 1 except that the temperature was changed to 30% and the water content of the water content crumb after draining in the first dehydration barrel was changed to 30%. (B) was obtained and each characteristic was evaluated. The results are shown in Table 2.

[Example 3]
Acrylic was carried out in the same manner as in Example 2 except that the monomer component was changed to 43 parts of ethyl acrylate, 25 parts of n-butyl acrylate, 26 parts of methoxyethyl acrylate, 2 parts of acrylonitrile and 4 parts of allylglycidyl ether. A rubber bale (C) was obtained and each characteristic (the compounding agent was replaced with "formulation 2") was evaluated. The results are shown in Table 2.

[Example 4]
Examples except that the monomer component was changed to 4.5 parts of ethyl acrylate, 64.5 parts of n-butyl acrylate, 39.5 parts of methoxyethyl acrylate, and 1.5 parts of mono-n-butyl fumarate. Acrylic rubber veil (D) was obtained in the same manner as in No. 2, and each characteristic (the compounding agent was changed to "formulation 3") was evaluated. The results are shown in Table 2.

[Example 5]
Example 2 except that the monomer component is changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile, and 1.3 parts of vinyl chloroacetate. In the same manner as above, an acrylic rubber bale (E) was obtained and each characteristic was evaluated. The results are shown in Table 2.

[Comparative Example 1]
A 0.7% sodium sulfate aqueous solution was added to an emulsified polymer solution (rotation speed 100 rpm, peripheral speed 0.5 m / s) that had been emulsified and polymerized in the same manner as in Example 5 to generate a hydrous crumb, and the water content after the formation. To 100 parts of the crumb, 194 parts of industrial water is added, and the mixture is stirred in the coagulation tank at 25 ° C. for 5 minutes, and then the water-containing crumb that discharges water from the coagulation tank is washed four times, and then a sulfuric acid aqueous solution having a pH of 3 After adding 194 parts and stirring at 25 ° C. for 5 minutes, water is discharged from the coagulation tank, and after performing acid cleaning once, 194 parts of pure water is added and pure water cleaning is performed once. The washed hydrous crumb was dried with a hot air dryer at 160 ° C. to obtain a crumb-shaped acrylic rubber (F) having a moisture content of 0.4% by weight. Each characteristic of the obtained crumb-shaped acrylic rubber (F) was evaluated and shown in Table 2.

[Reference example 1]
The washing step was carried out in the same manner as in Example 5, and the water-containing crumb after washing was dried with a hot air dryer at 160 ° C. to obtain a crumb-shaped acrylic rubber (G) having a water content of 0.4% by weight. Each characteristic of the obtained crumb-shaped acrylic rubber (G) was evaluated and shown in Table 2.

From Table 2, it is made of acrylic rubber having a reactive group of the present invention, the ash content is 0.2% by weight or less, the total amount of sodium and sulfur in the ash content is 30% by weight or more, and the sodium and the above. Acrylic rubber veils (A) to (E) having a ratio ([Na] / [S]) to sulfur in the range of 0.4 to 2.5 by weight are excellent in storage stability and water resistance, and moreover. It can be seen that the workability is also excellent (Examples 1 to 5).

Further, from Table 2, in the coagulation reaction, when the coagulation liquid is added to the emulsion polymerization solution to generate a hydrous crumb, the amount of ash is contained even if the washing step is performed 4 times with water, 1 time with acid, and 1 time with pure water. It can be seen that the water resistance is not sufficient without decreasing (Comparative Example 1). On the other hand, in the coagulation reaction, when an emulsion polymerization solution is added to a high-concentration coagulation solution that is vigorously agitated to some extent to generate a hydrous crumb, the ash content is reduced and the water resistance is reduced by washing with warm water twice. It can be seen that it is improved (Reference Example 1). Further, the solidification reaction is carried out in the same manner, the mixture is washed twice with warm water, and then dehydrated and dried with a screw type extruder to reduce the amount of ash in the acrylic rubber veil and significantly improve the water resistance. Understand (Examples 1 to 5).

From Table 2, the crumb-shaped acrylic rubber obtained by drying the washed hydrous crumb with hot air is sticky and loosely agglomerated, and its specific gravity is as small as 0.7, and it is in a state of entraining air (comparison). Example 1 and Reference Example 1). On the other hand, the acrylic rubber veils produced by drying with a screw type extruder, forming a sheet, and then laminating them all have a high specific gravity of 1.0 and contain almost no air. Furthermore, it can be seen that the veil is remarkably excellent in storage stability (Examples 1 to 5). This is substantially determined in the dry barrel portion depending on the conditions of the screw type extruder performed in the examples, for example, the water content crumb temperature to be charged, the water content in the dehydration barrel portion, the set temperature and decompression degree of the dry barrel portion, and the like. It was able to be reliably dried and melt-kneaded to a state where it did not contain moisture, and there was little air entrainment due to the resin pressure of the die part, the temperature of the extruded sheet-shaped dry rubber, the temperature of the sheet-shaped dry rubber during cutting, etc. Acrylic rubber bale with excellent water resistance is finally made by making a (large) acrylic rubber sheet and making a bale using the acrylic rubber sheet with less air entrainment and by a laminating method that allows air to escape easily. Is considered to have been manufactured.

From Table 2, further, although the gel amount of the clam-shaped acrylic rubber obtained by hot-air drying the washed hydrous crumb is large (Comparative Example 1 and Reference Example 1), it is possible to dry it with a screw type extruder, form a sheet, and then laminate it. It can be seen that the gel amount of all the produced acrylic rubber veils is reduced to 5% or less, and the workability is remarkably improved (Examples 1 to 5). This is because the gel amount of acrylic rubber increased rapidly because the polymerization reaction was carried out to a polymerization conversion rate of about 100% by emulsion polymerization, and the crumb-shaped acrylic rubber dried with hot air became a high gel amount as it was, but the screw type. By controlling the water content crumb temperature to be charged, the water content in the dehydration barrel, the set temperature of the drying barrel and the degree of decompression, etc. in the extruder, the drying barrel is dried to a state where it is substantially free of water. It is presumed that the gel that rapidly increased due to the polymerization reaction disappeared due to the melt-kneading.

1 Acrylic rubber manufacturing system 3 Coagulation equipment 4 Cleaning equipment 5 Screw type extruder 6 Cooling equipment 7 Veiling equipment

[Molecular weight and molecular weight distribution]
Regarding the weight average molecular weight (Mw) and molecular weight distribution ( Mz / Mw) of the acrylic rubber, lithium chloride was added to dimethylformamide at a concentration of 0.05 mol / L and 37% concentrated hydrochloric acid was added at a concentration of 0.01%, respectively. It is an absolute molecular weight and an absolute molecular weight distribution measured by the GPC-MALS method using a solution. Specifically, a multi-angle laser light scattering photometric meter (MALS) and a differential refractometer (RI) are incorporated into a GPC (Gel Permeation Chromatography) device, and the light scattering intensity and refraction of the molecular chain solution size-sorted by the GPC device are incorporated. The molecular weight of the solute and its content were sequentially calculated and obtained by measuring the rate difference with the elution time. The measurement conditions and measurement method by the GPC device are as follows.
Column: 2 TSKgel α-M (φ7.8 mm x 30 cm, manufactured by Tosoh Corporation)
Temperature: Column 40 ° C
Flow velocity: 0.8 ml / mm
Sample preparation: 5 ml of solvent was added to 10 mg of sample, and the mixture was gently stirred at room temperature (dissolution was visually observed). Then, filtration was performed using a 0.5 μm filter.
Injection volume: 0.200 ml

Claims (26)

It is made of acrylic rubber having a reactive group, the ash content is 0.2% by weight or less, the total amount of sodium and sulfur in the ash content is 30% by weight or more, and the ratio of sodium to sulfur ([Na] / [ S]) is an acrylic rubber veil in the range of 0.4 to 2.5 by weight. The acrylic rubber veil according to claim 1, wherein the amount of ash is 0.15% by weight or less. The acrylic rubber veil according to claim 1 or 2, wherein the acrylic rubber is mainly composed of (meth) acrylic acid ester. The invention according to any one of claims 1 to 3, wherein the acrylic rubber contains at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. Acrylic rubber veil. The acrylic rubber veil according to any one of claims 1 to 4, wherein the reactive group content is 0.01% by weight or more. The acrylic rubber veil according to any one of claims 1 to 5, wherein the complex viscosity ([η] 60 ° C.) at 60 ° C. is 15,000 Pa · s or less. When the ratio ([η] 100 ° C / [η] 60 ° C) of the complex viscosity at 100 ° C ([η] 100 ° C) to the complex viscosity at 60 ° C ([η] 60 ° C) is 0.5 or more. The acrylic rubber bale according to any one of claims 1 to 6. When the ratio ([η] 100 ° C / [η] 60 ° C) of the complex viscosity at 100 ° C ([η] 100 ° C) to the complex viscosity at 60 ° C ([η] 60 ° C) is 0.8 or more. The acrylic rubber bale according to any one of claims 1 to 6. The acrylic rubber veil according to any one of claims 1 to 8, which has a specific gravity in the range of 0.7 to 1.5. The acrylic rubber veil according to claim 9, which has a specific gravity in the range of 0.8 to 1.4. The acrylic rubber veil according to any one of claims 1 to 10, wherein the amount of gel is 50% by weight or less. The acrylic rubber veil according to any one of claims 1 to 11, which has a water content of less than 1% by weight. A monomer component containing a (meth) acrylic acid ester and a reactive group-containing monomer is emulsionized with water and a sodium sulfate ester as an emulsifier, and emulsion polymerization is carried out in the presence of a polymerization catalyst to obtain an emulsion polymerization solution. Emulsion polymerization process and
A coagulation step in which the obtained emulsion polymerization solution is brought into contact with the coagulation solution to form a hydrous crumb,
A cleaning process to clean the generated hydrous crumbs,
The washed water-containing crumb is dehydrated to a water content of 1 to 40% by weight in the dehydration barrel using a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip, and then in the drying barrel 1 Dehydration / drying / molding process that dries to less than% by weight and extrudes sheet-shaped dry rubber from the die.
A method for manufacturing an acrylic rubber veil, which includes a bale step of laminating extruded sheet-shaped dry rubber to make a veil. The method for producing an acrylic rubber veil according to claim 13, wherein the coagulant is a sulfate and / or a sodium salt. The method for producing an acrylic rubber veil according to claim 13 or 14, wherein the coagulant concentration of the coagulant is 0.5% by weight or more. The method for producing an acrylic rubber bale according to any one of claims 13 to 15, wherein the contact between the emulsion polymerization solution and the coagulation solution is performed by adding the emulsion polymerization solution to the agitated coagulation solution. .. The method for producing an acrylic rubber veil according to claim 16, wherein the number of stirrings of the coagulated liquid being stirred is 100 rpm or more. The method for producing an acrylic rubber veil according to claim 16 or 17, wherein the peripheral speed of the coagulated liquid being stirred is 0.5 m / s or more. The method for producing an acrylic rubber veil according to any one of claims 13 to 18, wherein the temperature of the hydrous crumb to be charged into the screw type extruder is 40 ° C. or higher. The method for producing an acrylic rubber veil according to any one of claims 13 to 19, wherein the sheet-shaped dry rubber is laminated after the sheet-shaped dry rubber is cut. The method for producing an acrylic rubber veil according to claim 20, wherein the sheet-shaped dry rubber is cut at a sheet-shaped dry rubber temperature of 60 ° C. or lower. The method for producing an acrylic rubber veil according to any one of claims 13 to 21, wherein the sheet-shaped dry rubber is laminated at a sheet-shaped dry rubber temperature of 30 ° C. or higher. A rubber mixture obtained by mixing a filler and a cross-linking agent with the acrylic rubber veil according to any one of claims 1 to 12. A method for producing a rubber mixture, which comprises mixing a filler and a cross-linking agent with the acrylic rubber veil according to any one of claims 1 to 12 with a mixer. A method for producing a rubber mixture, wherein the acrylic rubber veil according to any one of claims 1 to 12 and a filler are mixed, and then a cross-linking agent is mixed. A rubber crosslinked product obtained by cross-linking the rubber mixture according to claim 23.