JP6791412B1 - Acrylic rubber sheet with excellent water resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic rubber sheet having excellent storage stability and water resistance. SOLUTION: The acrylic rubber sheet according to the present invention has a weight average molecular weight (Mw) of 100,000 to 5,000,000 containing a (meth) acrylic acid ester as a main component, and has a z average molecular weight (Mz) and a weight average. It is made of acrylic rubber having a molecular weight (Mw) ratio (Mz / Mw) of 1.3 or more, an ash content of 0.2% by weight or less, a specific gravity of 0.8 or more, and a water content of less than 1% by weight. It has excellent storage stability and water resistance. This acrylic rubber sheet can be produced by dehydrating, drying, and molding a hydrous crumb obtained by coagulating a specific emulsion polymerization solution by a specific method by a specific method. [Selection diagram] None

Description

The present invention relates to an acrylic rubber sheet and its manufacturing method, an acrylic rubber bale and its manufacturing method, a rubber mixture and its manufacturing method, and a crosslinked rubber product. More specifically, an acrylic rubber sheet having excellent storage stability and water resistance and its manufacturing method. Manufacturing method, acrylic rubber bale made by laminating the acrylic rubber sheet and its manufacturing method, rubber mixture made by mixing the acrylic rubber sheet or acrylic rubber bale and its manufacturing method, and a rubber crosslinked product obtained by cross-linking the acrylic rubber sheet. Regarding.

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 obtained by emulsion polymerization of a monomer mixture constituting acrylic rubber, coagulation by adding a coagulant to the obtained emulsion polymerization solution, and drying the hydrous crumb obtained by coagulation. It is commercialized as a crumb, sheet or veil.

As a method for producing a crumb-shaped acrylic rubber, for example, in Patent Document 1 (International Publication No. 2018/079783 pamphlet), a monomer component composed of ethyl acrylate, 1n-butyl acrylate, and mono-n-butyl fumarate Is emulsified using an emulsifier composed of pure water, sodium lauryl sulfate and polyoxyethylene dodecyl ether, and emulsion polymerization is carried out in the presence of a polymerization initiator to a polymerization conversion rate of 95% by weight to obtain an emulsion polymerization solution, and sodium sulfate is continuously added. Then, the produced hydrous crumb was washed with industrial water four times, acid washed once with pH 3, and then washed with pure water once, and then put into a hot air dryer. Disclosed is a method for producing acrylic rubber, which is excellent in water resistance (volume change after immersion in 80 ° C. distilled water for 70 hours) with a small residual amount of emulsifier and coagulant by drying at 110 ° C. for 1 hour. However, it is not described that it is molded into a sheet and used, and handling the adhesive acrylic rubber in a crumb shape has a problem that workability and storage stability are inferior. Further, the obtained acrylic rubber is inferior in storage stability, and the water resistance is also required to be high in a harsher environment.

Regarding the production of sheet-shaped acrylic rubber, for example, Patent Document 2 (Japanese Unexamined Patent Publication No. 1-225512) describes a twin-screw extruder including a feed barrel, a dehydration barrel, a standard barrel, a vent barrel, and a vacuum barrel. Using, a nitrile rubber (NBR) crumb having 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. A method of continuously extruding into a strip through a die portion is disclosed, and it is also described that an acrylic rubber crumb is used as an applied rubber crumb. However, the patent document does not describe a method for obtaining an acrylic rubber sheet having excellent storage stability and water resistance.

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

The present invention has been made in view of such an actual situation, and an acrylic rubber sheet having excellent storage stability and water resistance and a method for producing the same, an acrylic rubber veil formed by laminating the acrylic rubber sheet and the method for producing the same, and the acrylic. An object of the present invention is to provide a rubber mixture obtained by mixing a rubber sheet or an acrylic rubber bale, a method for producing the same, and a rubber crosslinked product obtained by cross-linking the rubber mixture.

As a result of diligent research in view of the above problems, the present inventors have made acrylic rubber having a specific molecular weight with a (meth) acrylic acid ester as a main component and a specific molecular weight distribution with an emphasis on a high molecular weight region, and have a specific ash content and a specific specific gravity. It was also found that the acrylic rubber sheet having a specific water content is highly excellent in storage stability and water resistance.

The present inventors have also found that the effects of the present invention can be further improved when the amount of components in the ash, the complex viscoelasticity and viscosity at a specific temperature, and the Mooney viscosity are set within a specific range.

The present inventors also add an emulsion polymerization solution obtained by emulsion polymerization of a specific monomer component to a coagulating solution that has been vigorously stirred to some extent to generate a hydrous crumb, and the hydrous crumb after washing is made into a specific screw type. It has been found that an acrylic rubber sheet having excellent storage stability and water resistance can be easily produced by drying the sheet-shaped dried rubber to a specific water content with an extruder and extruding the sheet-shaped dried rubber.

In order to highly improve storage stability and water resistance, the present inventors also reduce the amount of ash by squeezing water from the water content crumb to a specific water content in the dehydration barrel portion of the screw type extruder. In addition, it is important to specify the moisture content crumb temperature, the set temperature of the drying barrel, and the degree of decompression that are put into the screw type extruder so that the drying barrel can be reliably dried to a specific moisture content that does not substantially contain water. I found that.

The present inventors also specify the resin pressure of the die part of the screw type extruder, the temperature of the sheet-shaped dry rubber to be extruded, and the temperature of the sheet-like dry rubber at the time of cutting to prevent air from being entrained in the acrylic rubber sheet. It has been found that the storage stability of the acrylic rubber sheet can be remarkably improved by extremely reducing the temperature (increasing the specific gravity).

Furthermore, the present inventors make it easier for the entrained air to escape by specifying the laminating temperature when the acrylic rubber sheet is laminated to produce the acrylic rubber bale, and as a result, the entrained air amount is small (the specific gravity is large). ), And found that an acrylic rubber bale with excellent storage stability can be produced.

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

Thus, according to the present invention , the weight average molecular weight ( with a (meth) acrylic acid ester as a main component and having a reactive group which is at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom ( It is made of acrylic rubber having a Mw) of 100,000 to 5,000,000 and a ratio (Mz / Mw) of z average molecular weight (Mz) to weight average molecular weight (Mw) of 1.3 or more, and has an ash content of 1.3 or more. 0.15 % by weight or less, JIS K6268 crosslinked rubber-Acrylic rubber having a specific gravity of 0.8 or more and a water content of less than 1% by weight and a thickness of 1 to 40 mm measured according to the method A of density measurement. Sheets are provided.

In the acrylic rubber sheet of the present invention, the amount of at least one element selected from the group consisting of sodium, sulfur, phosphorus, magnesium and calcium in the ash is preferably 50% by weight or more.

In the acrylic rubber sheet of the present invention, the total amount of sodium and sulfur in the ash is preferably 50% by weight or more.

In the acrylic rubber sheet of the present invention, the complex viscosity at 100 ° C. ([η] 100 ° C.) is preferably in the range of 1,500 to 6,000 Pa · s, and the complex viscosity at 60 ° C. ([η]]. 60 ° C.) is preferably 15,000 Pa · s or less. 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. The above is preferable.

Further, in the acrylic rubber sheet of the present invention, the Mooney viscosity (ML1 + 4,100 ° C.) is preferably in the range of 10 to 150.

Thus, according to the present invention, an emulsion polymerization step in which a monomer component containing (meth) acrylic acid ester as a main component is emulsified with water and an emulsifier and emulsion-polymerized in the presence of a polymerization catalyst to obtain an emulsion polymerization solution. , A coagulation step of adding the obtained emulsion polymerization solution to a coagulating liquid stirred at a peripheral speed of 0.5 m / s or more to generate a hydrous crumb, a cleaning step of washing the produced hydrous crumb, and a washed water-containing crumb. The crumb is dried to a water content of less than 1% by weight 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 the sheet-shaped dry rubber is extruded from the die. A method for producing an acrylic rubber sheet including a molding process is provided.

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

In the method for producing an acrylic rubber sheet of the present invention, it is preferable that the dehydration barrel portion of the screw type extruder squeezes out the water content in the water content crumb to a water content of 1 to 40% by weight.

In the method for producing an acrylic rubber sheet of the present invention, the set temperature of the drying barrel portion of the screw type extruder is preferably in the range of 100 to 250 ° C. Further, the set temperature of the drying barrel portion of the screw type extruder is preferably higher at the outlet portion than at the inlet portion, and the degree of decompression of the drying barrel portion of the screw type extruder is in the range of 1 to 50 kPa. preferable.

In the method for producing an acrylic rubber sheet of the present invention, the resin pressure of the die portion of the screw type extruder is preferably in the range of 0.1 to 10 MPa.

In the method for producing an acrylic rubber sheet of the present invention, it is preferable to provide a cutting step of cutting the sheet-shaped dried rubber extruded from the screw type extruder after the dehydration / drying / molding step.

In the method for producing an acrylic rubber sheet of the present invention, the temperature of the sheet-shaped dry rubber extruded from the screw type extruder is preferably in the range of 100 to 200 ° C.

In the method for producing an acrylic rubber sheet of the present invention, the cutting temperature of the sheet-shaped dry rubber is preferably 60 ° C. or lower.

According to the present invention, there is also provided an acrylic rubber veil formed by laminating the acrylic rubber sheets.

According to the present invention, there is also provided a method for producing an acrylic rubber veil, which comprises laminating the acrylic rubber sheets.

In the method for producing an acrylic rubber sheet of the present invention, the lamination temperature of the acrylic rubber sheet is preferably 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 sheet or acrylic rubber veil.

According to the present invention, there is also provided a method for producing a rubber mixture, which comprises mixing a filler and a cross-linking agent with the acrylic rubber sheet or the acrylic rubber bale using a mixer.

According to the present invention, there is also provided a method for producing a rubber mixture in which the above-mentioned acrylic rubber sheet or acrylic rubber veil and a filler are mixed and then a cross-linking agent is mixed.

According to the present invention, a rubber crosslinked product obtained by cross-linking the above rubber mixture is further provided.

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

It is a figure which shows typically an example of the acrylic rubber manufacturing system used for manufacturing the acrylic rubber sheet 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 sheet of the present invention has a weight average molecular weight (Mw) of 100,000 to 5,000,000 containing (meth) acrylic acid ester as a main component, and has a z average molecular weight (Mz) and a weight average molecular weight (Mw). It is made of acrylic rubber having a ratio (Mz / Mw) of 1.3 or more, an ash content of 0.2% by weight or less, a specific gravity of 0.8 or more, and a water content of less than 1% by weight. To do.

<Monomer component>
The acrylic rubber constituting the acrylic rubber sheet of the present invention contains (meth) acrylic acid ester as a main component. The ratio of the (meth) acrylic acid ester in the acrylic rubber is appropriately selected depending on the intended use, but is usually 50% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more. In the present invention, "(meth) acrylic acid ester" is used as a general term for esters of acrylic acid and / or methacrylic acid.

The acrylic rubber constituting the acrylic rubber sheet of the present invention 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. It is preferable because the crosslinked property of the rubber sheet can be highly improved.

Further, the acrylic rubber constituting the acrylic rubber sheet of the present invention is suitable because one containing a reactive group-containing monomer can highly improve heat resistance, compression set resistance, and the like.

As a preferable specific example of the acrylic rubber constituting the acrylic rubber sheet of the present invention, at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. , Reactive group-containing monomers, and, if necessary, other monomers copolymerizable.

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

Specific examples of such (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, etc., ethyl (meth) acrylate, (meth) acrylic N-butyl acid acid 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. Alkoxyalkyl esters include, more preferably (meth) acrylic acid alkoxyesters having an alkoxyalkyl group having 2 to 6 carbon atoms.

Specific examples of such (meth) acrylic acid alkoxyalkyl ester include methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, and (meth). Examples thereof include ethoxymethyl acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, and butoxyethyl (meth) acrylate. 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 may be used alone or in combination of two or more. The proportion of the ester in the 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 depending on the intended use without 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 particularly 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 and permanent strain resistance when the acrylic rubber sheet is made into a rubber crosslinked product.

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 silicic acid. And so on. The ethylenically unsaturated dicarboxylic acid is not particularly limited, but an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms is preferable, and for example, butenedioic acid such as fumaric acid and maleic acid, itaconic acid, and citraconic acid. , Chloromalic acid and the like. The ethylenically unsaturated dicarboxylic acid includes those existing as an anhydride.

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 2 to 6 carbon atoms of buthendioic acid having 4 carbon atoms can be used.

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 itaconic acid, monoethyl itaconic acid, monon-butyl itaconic acid, monocyclohexyl itaconic acid, 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.

(Meta) Acrylic Acid Ester Examples of the unsaturated alcohol ester of the halogen-containing saturated carboxylic acid include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate. 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. Examples thereof include 2-chloropropyl (meth) acrylic acid, 3-chloropropyl (meth) acrylic acid, and 2,3-dichloropropyl (meth) acrylic acid. 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- (chloroacetoxy). ) Propyl, 3- (hydroxychloroacetoxy) propyl (meth) acrylate and the like. Examples of the (meth) acrylic acid (haloacetylcarbamoyloxy) alkyl ester include (meth) acrylic acid 2- (chloroacetylcarbamoyloxy) ethyl and (meth) acrylic acid 3- (chloroacetylcarbamoyloxy) propyl. Be done. 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. Examples of the halogen-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, 2-chloroethyl allyl ketone and the like. Examples of the halomethyl group-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, and p-chloromethyl-α-methylstyrene. Examples of the halogen-containing unsaturated amide include N-chloromethyl (meth) acrylamide. 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 individually 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.

The monomer other than the above-mentioned monomer used as needed (hereinafter referred to as "other monomer") is not particularly limited as long as it can be copolymerized with the above-mentioned monomer. Examples thereof include aromatic vinyl, ethylenically unsaturated nitriles, acrylamide-based monomers, and other olefin-based monomers. Examples of the aromatic vinyl include styrene, α-methylstyrene, divinylbenzene and the like. Examples of the ethylenically unsaturated nitrile include acrylonitrile and methacrylonitrile. Examples of the acrylamide-based monomer include acrylamide and methacrylamide. Examples of other olefin-based monomers include ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, and butyl vinyl ether.

These 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, more preferably 0 to 0. It is in the range of 15 parts by weight, most preferably 0 to 10 parts by weight.

<Acrylic rubber>
The acrylic rubber constituting the acrylic rubber sheet of the present invention preferably has a reactive group.

The above-mentioned 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. Is preferably at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, because it can highly improve the crosslinked property of the acrylic rubber sheet. 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 content of the reactive group may be appropriately selected according to the purpose of use, but is usually 0.001 or more, preferably 0.001 to 5% by weight, more preferably 0, in terms of the weight ratio of the reactive group itself. Workability, strength properties, compressive permanent strain resistance, oil resistance, when in the range of 0 to 1-3% by weight, particularly preferably 0.05 to 1% by weight, most preferably 0.1 to 0.5% by weight. It is suitable because it has a high balance of properties such as cold resistance and water resistance.

Specific examples of the acrylic rubber constituting the acrylic rubber sheet of the present invention include at least one (meth) acrylic acid ester selected from (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester, and a reactive group. It consists of a containing monomer and other copolymerizable monomers contained as needed, and the proportion in each acrylic rubber is from (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester. At least one (meth) acrylic acid ester selected from the above group 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 99% by weight. In the range of% 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 1. It is in the range of ~ 3% by weight, and other monomers are usually in the range of 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. Is. By setting these monomers in acrylic rubber in the above range, the object of the present invention can be highly achieved, and water resistance and compression set resistance are remarkably improved when the acrylic rubber sheet is used as a crosslinked product. It is suitable because it is used.

The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber sheet of the present invention is not particularly limited, but is an absolute molecular weight measured by GPC-MALS, which is usually 100,000 to 5,000,000, preferably 500. Processing when mixing acrylic rubber sheets 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. It is suitable because it has a high balance of properties, strength characteristics, and compression set characteristics.

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 workability 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. It is preferable because it can alleviate changes in physical properties during storage.

The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber sheet of the present invention is not 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 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 lower limit or higher, the oil resistance and heat resistance can be improved, and by setting the glass transition temperature to the above upper limit or lower, the cold resistance and workability can be improved.

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

<Acrylic rubber sheet>
The acrylic rubber sheet of the present invention is characterized by being made of the acrylic rubber and having an ash content, a specific gravity and a water content within a specific range.

The thickness of the acrylic rubber sheet of the present invention 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 a high balance of storage stability and productivity. In particular, the thickness of a low-priced acrylic rubber sheet with significantly improved productivity is usually in the range of 1 to 30 mm, preferably 2 to 25 mm, more preferably 3 to 15 mm, and particularly preferably 4 to 12 mm.

The width of the acrylic rubber sheet of the present invention is also appropriately selected depending on the intended 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. It is particularly suitable because it is easy to handle.

The length of the acrylic rubber sheet of the present invention is not particularly limited, but is particularly handled when it is usually in the range of 300 to 1,200 mm, preferably 400 to 1,000 mm, and more preferably 500 to 800 mm. It has excellent properties and is suitable.

The ash content of the acrylic rubber sheet of the present invention is 0 . When it is 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 excellent in storage stability and water resistance. ..

The lower limit of the ash content of the acrylic rubber sheet 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, the metal adhesion of the acrylic rubber sheet is suppressed, and the workability is excellent and suitable.

Storage stability and water resistance and metal adhesion and ash content to highly balance the acrylic rubber sheet of the present invention, good Mashiku is 0.0005 to 0.15 wt%, more preferably 0.001 to 0. It is in the range of 12% by weight, particularly preferably 0.05 to 0.11% by weight, and most preferably 0.01 to 0.1% by weight.

In the acrylic rubber sheet of the present invention, the content of at least one element selected from the group consisting of sodium, sulfur, calcium, magnesium and phosphorus in the ash content is not particularly limited, but is at least 30% by weight. The acrylic rubber sheet is highly excellent in storage stability and water resistance, preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more.

The total amount of sodium and sulfur in the ash content of the acrylic rubber sheet of the present invention is not particularly limited, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, particularly. When it is preferably 80% by weight or more, the storage stability and water resistance of the acrylic rubber sheet are highly excellent and suitable.

The ratio of sodium to sulfur ([Na] / [S]) in the ash content of the acrylic rubber sheet of the present invention is not particularly limited, but is usually 0.4 to 2.5, preferably 0.4 to 2.5 by weight. Is 0.6 to 2, more preferably 0.8 to 1.7, and particularly preferably 1 to 1.5, the water resistance of the acrylic rubber sheet is highly excellent and suitable.

The specific gravity of the acrylic rubber sheet of the present invention is not particularly limited, but is usually 0.8 or more, preferably 0.8 to 1.4, more preferably 0.9 to 1.3, and particularly preferably 0.95 to 1. When it is in the range of 0.25, most preferably 1.0 to 1.2, the storage stability of the acrylic rubber sheet is highly excellent and suitable.

The water content of the acrylic rubber sheet of the present invention is not particularly limited, but is usually added when it is less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. The vulcanization (crosslinking) characteristics are optimized, and the products have highly excellent properties such as heat resistance and water resistance, which are suitable.

The gel amount of the acrylic rubber sheet of the present invention is the insoluble content of methyl ethyl ketone, and is usually 50% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less, most preferably. When it is 5% by weight or less, the workability is highly improved and is suitable.

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 of the acrylic rubber sheet is highly improved and is suitable.

The complex viscosity ([η] 60 ° C.) of the acrylic rubber sheet of the present invention 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. When it is in the range of 2,500 to 7,000 Pa · s, most preferably 2,700 to 5,500 Pa · s, the acrylic rubber sheet is excellent in processability, oil resistance and shape retention, and is suitable.

The complex viscosity ([η] 100 ° C.) of the acrylic rubber sheet 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 the range is 000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s, the processability, oil resistance and shape retention of the acrylic rubber sheet are improved. Excellent and suitable.

Further, the ratio of the complex viscosity ([η] 100 ° C.) of the acrylic rubber sheet 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 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. In this case, the processability, oil resistance and shape retention of the acrylic rubber sheet are highly balanced, which is preferable.

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

<Manufacturing method of acrylic rubber sheet>
The method for producing such an acrylic rubber sheet is not particularly limited, but can be produced, for example, by the production method of the present invention including the following steps (1) to (4). That is,
(1) Emulsion polymerization step of emulsifying a monomer component containing (meth) acrylic acid ester as a main component with water and an emulsifier and emulsion polymerization in the presence of a polymerization catalyst to obtain an emulsion polymerization solution;
(2) A coagulation step of adding the obtained emulsion polymerization solution to a coagulation solution stirred at a peripheral speed of 0.5 m / s or more to form a hydrous crumb;
(3) Cleaning step for cleaning the produced hydrous crumb;
(4) The washed hydrous crumb is dried to a moisture content of less than 1% by weight 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 to form a sheet-shaped dry rubber. Dehydration / drying / molding process extruded from the die;
It can be easily manufactured by a manufacturing method including.

(Emulsion polymerization process)
In the emulsion polymerization step in the method for producing an acrylic rubber sheet of the present invention, a monomer component containing (meth) acrylic acid ester as a main component is emulsified with water and an emulsifier, and emulsion polymerization is carried out in the presence of a polymerization catalyst to form an emulsion polymerization solution. It is characterized by obtaining.

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

The emulsifier used in the emulsion polymerization step is not particularly limited and may follow a conventional method, and examples thereof include an anionic emulsifier, a cationic emulsifier, and a nonionic emulsifier. Among these, anionic emulsifiers and nonionic emulsifiers are preferable, anionic emulsifiers are particularly preferable, and sulfuric acid-based emulsifiers are most preferable.

As the anionic emulsifier, those normally used can be used without particular limitation, and examples thereof include fatty acid emulsifiers, sulfonic acid emulsifiers, sulfosuccinic acid emulsifiers, sulfuric acid emulsifiers, and phosphoric acid emulsifiers, and preferable ones. Sulfuric acid emulsifier can be used.

The fatty acid-based emulsifier is not particularly limited, and examples thereof include sodium octanate, sodium decanoate, sodium laurate, sodium myristate, sodium palmitate, and sodium stearate.

The sulfonic acid-based emulsifier is not particularly limited, but for example, sodium hexane sulfonate, sodium octane sulfonate, sodium decane sulfonate, sodium toluene sulfonate, sodium cumene sulfonate, sodium octylbenzene sulfonate, dodecylbenzene sulfone. Examples thereof include sodium acid, ammonium dodecylbenzene sulfonate, sodium naphthalene sulfonate, sodium alkylnaphthalene sulfonate, sodium alkyldiphenyl ether disulfonate and the like.

The sulfosuccinic acid-based emulsifier is not particularly limited, and examples thereof include sodium dioctyl sulfosuccinate and sodium dihexyl sulfosuccinate.

The sulfuric acid-based emulsifier is not particularly limited and may follow a conventional method, but a sulfuric acid ester salt can be preferably used. Suitable sulfates include, for example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkyl sulfate, sodium polyoxyethylene alkylaryl sulfate, and the like, among which lauryl sulfate is used. Sodium is particularly suitable.

The phosphoric acid-based emulsifier is not particularly limited, and examples thereof include sodium lauryl phosphate, potassium lauryl phosphate, sodium polyoxyalkylene alkyl ether phosphate, and the like.

Examples of the cationic emulsifier include, but are not limited to, alkyltrimethylammonium chloride, dialkylammonium chloride, benzylammonium chloride and the like.

The nonionic emulsifier is not particularly limited, but for example, a polyoxyalkylene fatty acid ester such as polyoxyethylene stearate ester; a polyoxyalkylene alkyl ether such as polyoxyethylene dodecyl ether; a polyoxy such as polyoxyethylene nonylphenyl ether. Alkylene alkylphenol ether; polyoxyethylene sorbitan alkyl ester and the like can be mentioned, and polyoxyalkylene alkyl ether and polyoxyalkylene alkyl phenol ether are preferable, and polyoxyethylene alkyl ether and polyoxyethylene alkyl phenol ether are more preferable.

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

As a method of mixing the monomer component, water and emulsifier, a conventional method may be followed, and examples thereof include a method of stirring the monomer, emulsifier and water using a stirrer such as a homogenizer or a disk turbine. .. 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 in the emulsion polymerization may be one usually used in the emulsion polymerization, and the type thereof is not limited, but 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 limited as long as it is used in emulsion polymerization, and is, for example, 2,2-di (4,5-di- (t-butylperoxy) cyclohexyl) propane, 1-di. -(T-Hexylperoxy) cyclohexane, 1,1-di- (t-butylperoxy) cyclohexane, 4,4-di- (t-butylperoxy) n-butyl valerate, 2,2-di- (T-Butyl Peroxy) Butan, t-Butyl Hydroperoxide, Cumen Hydroperoxide, Diisopropylbenzene Hydroperoxide, Paramentan Hydroperoxide, Benzoyl Peroxide, 1,1,3,3-Tetraethylbutyl Hydroperoxide , T-Butyl cumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di (2-t-butyl peroxyisopropyl) 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, diisobutyrylper Oxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, 1,1,3,3-tetramethylbutylperoxyneodeca Nate, t-hexyl peroxypivalate, t-butylperoxyneodecanate, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-di (2-ethyl) Hexanoyl peroxy) 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 (benzoylper) Oxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di (t-butylpa) -Oxy) Hexane and the like can be mentioned, and among these, diisopropylbenzene hydroperoxide, cumene hydroperoxide, paramentan hydroperoxide, 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 (propan-2-carboamidine), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropaneamide], 2,2'-azobis {2- [1- (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 can be mentioned.

These radical generators can be used individually or in combination of two or more, and the amount used is usually 0.0001 to 5 parts by weight, preferably 0.% by weight, 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 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. Each of 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. With respect to 100 parts by weight of the monomer component. It is in the range of 01 parts by weight, preferably 0.00001 to 0.001 parts by weight, and 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, aldehyde sodium hydrogen 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 sulfite 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 alone or in combination of two or more, and the amount used is usually 0.001 with respect 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.

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. It is in the range of 0.0005 to 0.0005 parts by weight, and the amount of ascorbic acid or a salt thereof and / or sodium formaldehyde sulfoxylate used is usually 0.001 to 1 part by weight with respect to 100 parts by weight of the monomer component. It is preferably 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 amount used at the time of emulsification of the above-mentioned monomer component, but is usually 10 to 1000 parts by weight, preferably 10 to 1000 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 50 to 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 limited, but is usually excellent in the strength characteristics of the acrylic rubber sheet produced when it is 80% by weight or more, preferably 90% by weight or more, and more preferably 95% by weight or more. It is suitable because it has no monomeric odor. A polymerization inhibitor may be used to terminate the polymerization.

(Coagulation process)
In the coagulation step in the method for producing an acrylic rubber sheet of the present invention, the emulsion polymerization solution obtained as described above is added to a coagulation solution (coagulant-containing aqueous solution) stirred at a peripheral speed of 0.5 m / s. It is characterized by producing a hydrous crumb.

The solid content concentration of the emulsion polymerization solution used in the coagulation step is not 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.

The coagulant used in the coagulation step is not particularly limited, but a metal salt is usually 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, and more preferably alkali metal salts.

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. Among these, sodium salts are preferable, and sodium chloride and sodium sulfate are particularly preferable. Examples of the Group 2 metal salt in 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 used as coagulants 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.

These coagulants can be used individually or in combination of two or more, and the amount used is usually 0.01 to 100 parts by weight, preferably 0.1 to 100 parts by weight, based on 100 parts by weight of the monomer component. It is in the range of 50 parts by weight, more preferably 1 to 30 parts by weight. When the amount of the coagulant is in this range, it is preferable because it is possible to highly improve the compression set resistance and water resistance when the acrylic rubber sheet is crosslinked while making the acrylic rubber solidify sufficiently. is there.

The coagulant is usually used as an aqueous solution thereof, but the coagulant concentration of the coagulant solution (coagulant aqueous solution) is usually 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1. When it is in the range of 10% by weight, particularly preferably 1.5 to 5% by weight, the particle size of the hydrous crumb to be produced can be uniformly focused in a specific region, which is preferable.

The temperature of the coagulating liquid is not particularly limited, but is preferably 40 ° C. or higher, preferably 40 to 90 ° C., more preferably 50 to 80 ° C., because a uniform water-containing crumb is generated.

The peripheral speed (flow velocity) of the coagulated liquid being agitated is represented by the linear velocity of the outer circumference of the stirring blade of the stirrer provided in the coagulation bath. It is preferable that the coagulated liquid is vigorously stirred to a certain degree because the particle size of the water-containing crumbs produced can be made small and uniform, and the peripheral speed is 0.5 m / s or more, preferably 1 m / s or more, more preferably. It is 1.5 m / s or more, particularly preferably 2 m / s or more, and most preferably 2.5 m / s or more. On the other hand, the upper limit of the peripheral speed is not limited, but usually controls the solidification reaction when it is 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. Is easy and suitable.

The stirring speed (rotation speed) of the coagulated liquid being stirred is the rotation speed of the stirring blade of the stirring device provided in the coagulation bath, and is not particularly limited as long as the coagulating liquid is vigorously stirred to a certain degree, but is usually 100 rpm. As described above, the range is preferably 200 to 1,000 rpm, more preferably 300 to 900 rpm, and particularly preferably 400 to 800 rpm. It is preferable that the rotation speed is such that the coagulant is stirred violently to some extent because the generated hydrous crumb particle size can be made small and uniform. By setting the rotation speed to be equal to or higher than the above lower limit, the crumb particle size is set. It is possible to suppress the formation of an excessively large or small substance, and by setting the rotation speed to be equal to or less than the above upper limit, it becomes easier to control the solidification reaction.

In the present invention, 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.) are set within a specific range. By adjusting, the shape and crumb diameter of the produced hydrous crumb are uniform and focused, and the removal of emulsifiers and coagulants during cleaning and dehydration is significantly improved.

The hydrous crumbs thus produced preferably satisfy the following (a) to (e) when all the hydrous crumbs obtained in the solidification step are screened by 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 but 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 but 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 but not 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.

That is, in the above-mentioned sieving of all the water-containing crumbs produced, (a) the proportion of the water-containing crumbs that do 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. When the following, the cleaning efficiency of the emulsifier and the coagulant can be remarkably improved, which is preferable. Further, (b) the proportion of the hydrous crumb that passes through the 9.5 mm mesh JIS sieve and does not pass through the 6.7 mm JIS sieve is 30% by weight or less, preferably 20% by weight or less, more preferably 5% by weight or less. When it is, the cleaning efficiency of the emulsifier and the coagulant can be remarkably improved, which is preferable. Further, (c) the proportion of the hydrous crumb that passes through the JIS sieve with an opening of 6.7 mm and does not pass through the JIS sieve of 710 μm is 20% by weight or more, preferably 40% by weight or more, more preferably 70% by weight or more, and most. When it is preferably 80% by weight or more, the cleaning efficiency of the emulsifier or coagulant can be remarkably improved, which is preferable. Further, (d) when the proportion of the hydrous crumb that passes through the JIS sieve with an opening of 710 μm and does not pass through the JIS sieve with a mesh size of 425 μm is 30% by weight or less, preferably 20% by weight or less, and more preferably 15% by weight or less. It is suitable because the cleaning efficiency of emulsifiers and coagulants is remarkably improved and the productivity is also increased. Then, (e) when the proportion of the small-diameter hydrous crumb passing through the JIS sieve having an opening of 425 μm is 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, the emulsifier or coagulant is used. It is suitable because the cleaning efficiency is remarkably improved and the productivity is also increased.

In the present invention, the proportion of the water-containing crumbs produced that (f) pass through the JIS sieve with an opening of 6.7 mm and do not pass through the JIS sieve with an opening of 4.75 mm is 40% by weight. Hereinafter, when it is preferably 10% by weight or less, more preferably 5% by weight or less, the cleaning efficiency of the emulsifier or coagulant is improved, which is preferable.

In the present invention, the proportion of the water-containing crumbs produced that (g) pass through the JIS sieve with an opening of 4.75 mm and do not pass through the JIS sieve with an opening of 710 μm is 40% by weight or more. When it is preferably 60% by weight or more, more preferably 80% by weight or more, the removal efficiency of the emulsifier and coagulant during washing and dehydration is remarkably improved, which is preferable.

Further, in the present invention, the proportion of the water-containing crumbs produced which (h) pass through the JIS sieve having a mesh size of 3.35 mm and do not pass through the JIS sieve having a mesh size of 710 μm is 20% by weight or more. When it is preferably 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 high. It is improved and suitable.

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

The cleaning method is not particularly limited and may follow a conventional method. For example, the produced hydrous crumb can be mixed with a large amount of water.

The amount of water used for washing is not particularly 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. It is preferable that the amount of ash in the acrylic rubber sheet can be effectively reduced when the range is more preferably 100 to 10,000 parts by weight, particularly preferably 150 to 5,000 parts by weight.

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

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 is also not particularly 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 sheet, it is desirable that the number of washings is large, but the shape of the water-containing crumb and the diameter of the water-containing crumb are specified as described above. And / or 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 sheet of the present invention, the washed hydrous 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. The sheet-shaped dry rubber is extruded from the die after being dried to a water content of less than 1% by weight.

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 sheet 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 draining machine or the like after the washing step and before the dehydration / drying step. Therefore, the dehydration efficiency can be increased.

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

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 step is not particularly limited, but is usually 50 to 80% by weight, preferably 50 to 70% by weight, and more. It is preferably in the range of 50 to 60% by weight.

The temperature of the hydrous crumb after draining, that is, the temperature of the hydrous crumb put into the dehydration / drying step is not particularly limited, but is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C. When the temperature is in the range of ° C., particularly preferably 55 to 85 ° C., most preferably 60 to 80 ° C., the temperature is raised as high as 1.5 to 2.5 KJ / kg · K as in the acrylic rubber of the present invention. Even a difficult water-containing crumb is suitable because it can be efficiently dehydrated and dried using a screw type extruder.

Dehydration of hydrous crumbs (dehydration barrel)
Dehydration of the water content crumb is performed in a dehydration barrel equipped with a dehydration slit provided in a screw type extruder, and when the water content in the water content crumb is squeezed out to a water content of 1 to 40% by weight, the amount of ash in the acrylic rubber sheet. It is suitable because it can reduce the amount of water and significantly improve the water resistance of the acrylic rubber sheet.

The opening of the dehydration slit provided in the dehydration barrel may be appropriately selected according to the conditions of use, but is usually 0.01 to 5 mm, preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm. When it is within the range, the loss of the hydrous crumb is small and the dehydration of the water cut crumb can be efficiently performed, which is preferable.

The number of dehydration barrels in the screw extruder is not limited, but usually, when the number is usually a plurality, preferably 2 to 10, more preferably 3 to 6, in order to efficiently dehydrate the adhesive acrylic rubber. Is suitable.

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 vapor (exhaust vapor). In the present invention, the drainage is dehydrated. 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 and dry the adhesive acrylic rubber. Dehydration that squeezes water from the hydrous crumb refers to dehydration by the above drainage (dehydration in a drainage type dehydration barrel described later).

In a screw type extruder equipped with three or more dehydration barrels, the selection of whether each dehydration 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 sheet, the number of drainage type dehydration barrels is increased, and to reduce the water content, the number of exhaust steam type dehydration barrels is increased.

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 drainage type dehydration barrel that dehydrates in the drainage 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 exhaust steam type dehydration barrel that dehydrates in the exhaust 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 limited, but is usually 1 to 40% by weight, preferably 5 to 40% by weight, and more preferably 5 to 35% by weight. Most preferably, when the content is 10 to 35% by weight, the amount of ash in the acrylic rubber sheet can be significantly reduced, which is preferable.

When dehydration of adhesive acrylic rubber having a reactive group is performed using a centrifuge or the like, the acrylic rubber adheres to the dehydration slit portion and can hardly be dehydrated, and the water content is up to about 45 to 55% by weight. However, in the present invention, the water content can be reduced to the above range by using a screw type extruder having a dehydration slit and forcibly squeezed with a screw.

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 the dehydration step to be equal to or higher than the above lower limit value, the dehydration time can be shortened and deterioration of acrylic rubber can be suppressed, and by setting the water content to be equal to or lower than the above upper limit value, 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, 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 sheet 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 dry barrels, the set temperature may be an approximate temperature for all the dry barrels or may be changed for each barrel, but the temperature of the discharge part (closer to the dehydration barrel) is higher than that of the introduction part (closer to the dehydration barrel). It is preferable to raise the temperature (closer to the die) because the drying efficiency can be increased.

The water content of the dried rubber after drying is not particularly limited, but 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 that the gel amount of the acrylic rubber sheet can be reduced by melt-extruding the dry rubber in a screw type extruder so that the water content of the dry rubber becomes this value (substantially free of water). ..

Dry rubber (die part)
The dried rubber dehydrated and dried by the screw portion of the dehydration barrel and the drying barrel 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 dried rubber extruded from the die portion of the screw type extruder is suitable because the die shape is made substantially rectangular and extruded into a sheet shape, so that air entrainment is small and the dry rubber having a large specific gravity and excellent storage stability can be obtained. ..

The resin pressure in the die portion is not particularly limited, but when it is usually in the range of 0.1 to 10 MPa, preferably 0.5 to 5 MPa, more preferably 1 to 3 MPa, there is little air entrainment during extrusion. Not only does the acrylic rubber sheet have a high specific gravity, but it is also excellent in productivity and suitable.

Screw-type extruder and operating conditions The screw length (L) of the screw-type extruder used may be appropriately selected according to the purpose of use, but is usually 3,000 to 15,000 mm, preferably 4,000 to. It is in the range of 10,000 mm, more preferably 4,500 to 8,000 mm. The screw diameter (D) of the screw type extruder may be 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. It is preferable that the water content is in the range of 30 to 60 because the water content can be reduced to less than 1% by weight without lowering the molecular weight of the dried rubber or causing discoloration.

The rotation speed (N) of the screw type extruder used may be 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. Is suitable because it can efficiently reduce the water content and gel amount of acrylic rubber when the speed is 120 to 300 rpm.

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, and more preferably 400 to 1,000 kg / hr. It is in the range of hr, most preferably 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. It is in the range of ~ 6.

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 can be increased without entraining air, and the storage stability is highly improved, which is suitable. The sheet-shaped dry rubber extruded from the screw type extruder is preferably cut after cooling and used as an acrylic rubber sheet.

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 is 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 there.

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 not particularly limited, but is usually 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 limited, but is usually 1,500 to 6,000 Pa · s, preferably 2,000 to 5, When the range is 000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s, the extrudability as a sheet and the shape retention are highly balanced. Is suitable. That is, by setting the above value to the lower limit or more, the extrudability can be improved, and by setting the value to the upper limit or less, the shape of the sheet-shaped dried rubber can be suppressed from collapsing or breaking.

The sheet-shaped dry rubber extruded from the screw type extruder may be folded and used as it is, but is preferably cut and used.

Since the sheet-shaped dry rubber has a strong adhesiveness, it is preferable to cool the sheet-shaped dry rubber in order to continuously cut the sheet-shaped dry rubber without entraining air.

The cutting temperature of the sheet-shaped dry rubber is not limited, but when the cutting temperature is usually 60 ° C. or lower, preferably 55 ° C. or lower, more preferably 50 ° C. or lower, the cutability and productivity are highly balanced. It is suitable.

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

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 dried rubber is When cutting, but not limited to, 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 there is little air entrainment and the cutting and productivity are highly balanced.

There are no particular restrictions on the cooling method of the sheet-shaped dry rubber, and it may be left at room temperature to cool, but since the thermal conductivity of the sheet-shaped dry rubber is very small, 0.15 to 0.35 W / mK. In addition, forced cooling such as an air-cooling method under blowing or cooling, a watering method for spraying water, or a dipping method for immersing in water is preferable for increasing productivity, and an air-cooling method under blowing or cooling is particularly preferable. ..

In the air-cooling method of the 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 particularly 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 particularly limited, but is usually in the range of 5 to 500 m, preferably 10 to 200 m, and more preferably 20 to 100 m. The cooling rate of the sheet-shaped dry rubber is not particularly limited, but the cutting is particularly limited when it is usually 50 ° C./hr or more, more preferably 100 ° C./hr or more, and more preferably 150 ° C./hr or more. It is easy and suitable.

The cutting length of the sheet-shaped dry rubber is not particularly limited and is appropriately selected depending on the intended use, but is usually in the range of 100 to 800 mm, preferably 200 to 500 mm, and more preferably 250 to 450 mm.

The acrylic rubber sheet thus obtained is superior in operability and storage stability as compared with crumb-shaped acrylic rubber, and can be used as it is or after being laminated and veiled.

<Acrylic rubber veil>
The acrylic rubber veil of the present invention is characterized by laminating the above acrylic rubber sheets. The number of layers is appropriately selected according to the size or weight of the acrylic rubber veil.

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 1,200 mm, preferably. Is in the range of 400 to 1,000 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.

Reactive group content, water content, ash content, component content and ratio in ash, specific gravity, gel amount, pH, complex viscosity at 60 ° C. ([η] 60 ° C.), at 100 ° C. of the acrylic rubber veil of the present invention. Complex viscosity ([η] 100 ° C), ratio of complex viscosity at 100 ° C ([η] 100 ° C) to complex viscosity at 60 ° C ([η] 60 ° C) ([η] 100 ° C / [η] ] 60 ° C.) and Mooney viscosity (ML1 + 4,100 ° C.) are the same as the respective characteristic values of the acrylic rubber sheet.

The method for producing the acrylic rubber veil of the present invention is not particularly limited, but it can be easily produced by cooling and cutting the sheet-shaped dry rubber extruded from the screw type extruder, and then laminating and integrating them.

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 laminated layers may be appropriately selected according to the size or weight of the acrylic rubber bale.

The acrylic rubber veil of the present invention thus obtained has excellent operability, water resistance, strength characteristics and workability as compared with crumb-shaped acrylic rubber, and the acrylic rubber veil can be used as it is or by cutting a required amount into a banbury or roll. It can be used by putting it in a mixer such as.

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

The filler contained in the rubber mixture of the present invention is not particularly limited, and examples thereof include a reinforcing filler and a non-reinforcing filler, and a reinforcing filler is preferable.

The reinforcing filler is not particularly limited, but is, for example, 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 so on. Examples of the non-reinforcing filler include quartz powder, silica soil, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, barium sulfate and the like. Can be mentioned.

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

The cross-linking agent may be appropriately selected depending on the type and application of the reactive group contained in the acrylic rubber constituting the acrylic rubber sheet or the acrylic rubber bale, but the acrylic rubber sheet or the acrylic rubber bale can be cross-linked. The compound is not particularly limited as long as it is, for example, a polyvalent amine compound such as a diamine compound and a carbonate thereof; a sulfur compound; a sulfur donor; a triazinethiol compound; a polyvalent epoxy compound; an ammonium salt of an organic carboxylate; an organic peroxide. Conventionally known cross-linking agents such as: polyvalent carboxylic acid; quaternary 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 sheet or acrylic rubber veil used in the mixture is composed of a carboxyl group-containing acrylic rubber, it is preferable to use a polyvalent amine compound and a carbonate thereof as a suitable cross-linking agent. Examples of the polyvalent amine compound include aliphatic polyvalent amine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, and N, N'-dicinnamylidene-1,6-hexanediamine; 4,4'-methylenedianiline, p. -Phenylenediamine, m-Phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-(m-Phenylenediisopropyridene) dianiline, 4,4'-(p-phenylenedi) Isopropylidene) dianiline, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, 4,4'-bis (4-aminophenoxy) biphenyl, m-xyli Aromatic polyvalent amine compounds such as rangeamine, 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 sheet or acrylic rubber veil to be used is composed of epoxy group-containing acrylic rubber, aliphatic polyvalent amine compounds such as hexamethylenediamine and hexamethylenediamine carbamate and their carbonates are used as cross-linking agents; 4, 4 Aromatic polyvalent amine compounds such as'-methylene 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 tetradecanedioic acid; cetyl A quaternary onium salt such as trimethylammonium bromide; an imidazole compound such as 2-methylimidazole; an isocyanuric acid compound such as ammonium isocyanurate; and the like can be used, and among these, an ammonium carboxylic acid salt and a metal dithiocarbamate salt are preferable. Ammonium benzoate is more preferred.

When the acrylic rubber sheet or 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.

These cross-linking agents can be used individually or in combination of two or more, and the blending amount thereof is usually 0.001 to 20 parts by weight, preferably 0, based on 100 parts by weight of the acrylic rubber sheet or acrylic rubber veil. .1 to 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, in addition to the above components, other rubber components other than the acrylic rubber sheet or the acrylic rubber veil can be used, if necessary.

Other rubber components used as needed are not particularly limited, and for example, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicon rubber, fluororubber, olefin elastomer, etc. Examples thereof include styrene-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, and polysiloxane-based elastomers. The shape of these other rubber components is not limited, and may be, for example, a powder or granular material, a pellet, a crumb, a sheet, or a veil.

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

An anti-aging agent can be added to the rubber mixture of the present invention, if necessary. The type of 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) , 2,6-di-t-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine-2-ylamino) Other phenolic anti-aging agents such as 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 -Naphthylamine, p- (p-toluenesulfonylamide) -diphenylamine, 4,4'-(α, α-dimethylbenzyl) diphenylamine, N, N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl- Amin-based anti-aging agents such as p-phenylenediamine, butylaldehyde-aniline condensates; imidazole-based anti-aging agents such as 2-mercaptobenzimidazole; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin Kinolin-based anti-aging agents such as 2,5-di- (t-amyl) hydroquinone and other hydroquinone-based anti-aging agents; and the like. Among these, amine-based antiaging 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 0.01 to 15 parts by weight, based on 100 parts by weight of the acrylic rubber sheet or acrylic rubber veil. It is in the range of 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight.

The rubber mixture of the present invention contains the acrylic rubber sheet or 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 further, if necessary, in the art. Other commonly used additives such as cross-linking aids, cross-linking accelerators, cross-linking retarders, silane coupling agents, plasticizing agents, processing aids, rubbers, pigments, colorants, antioxidants, foaming agents, etc. Can be arbitrarily blended. 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 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 in the acrylic rubber sheet or the acrylic rubber veil of the present invention as needed. In 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, the desired rubber mixture can be obtained by directly mixing, preferably directly kneading, the acrylic rubber sheet or the acrylic rubber veil with the filler, the cross-linking agent, etc. using these mixers.

In that case, the acrylic rubber sheet or the acrylic rubber veil may be used as it is, or may be used after being divided (cut or the like) in advance.

The mixing procedure of each of the above components is not limited, but for example, after sufficiently mixing the components that are difficult to react or decompose with heat, the temperature at which the reaction or decomposition does not occur with the cross-linking agent, which is a component that easily reacts or decomposes with heat. Two-step mixing is preferable, in which the mixture is mixed in a short time. Specifically, it is preferable to mix the acrylic rubber sheet or acrylic rubber veil and the filler in the first stage, and then mix the cross-linking agent in the second stage. The other rubber components and the antiaging agent are usually mixed in the first stage, the cross-linking accelerator may be in the second stage, and the combination of the 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 not particularly limited, but is usually in the range of 10 to 150, preferably 20 to 100, and more preferably 25 to 80. Is.

<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 described above and molded by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor or a roll, and heated. It can be produced by carrying out a cross-linking reaction and fixing the shape as a rubber cross-linked product. In this case, 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 obtained crosslinked rubber product of the present invention has excellent water resistance while maintaining basic properties as rubber such as tensile strength, elongation, and hardness.

The rubber crosslinked product of the present invention makes use of the above-mentioned excellent properties, for example, O-ring, packing, diaphragm, oil seal, shaft seal, bearing sheath, mechanical seal, well head seal, seal for electric / electronic equipment, and the like. Sealing materials such as seals for air compression equipment; 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. Various gaskets such as gaskets for fuel cell separators and gaskets for the top cover of hard disk drives mounted between a pair of housings that sandwich a unit cell with a plate and a negative electrode; cushioning material, vibration isolator; wire coating material; industrial belt Classes; tubes / 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 sheets>
Next, an apparatus configuration used for manufacturing an acrylic rubber sheet 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 sheet according to an embodiment of the present invention. For the production of the acrylic rubber sheet 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 an emulsifier are mixed with a monomer component for forming acrylic rubber, emulsified while being appropriately stirred with a stirrer, and emulsion polymerization is carried out in the presence of a polymerization catalyst to form 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 and coagulating it.

In the coagulation device 3, for example, the contact between the emulsion polymerization solution and the coagulation solution adopts a method of adding the emulsion polymerization solution to the stirring coagulation solution. That is, a hydrous 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 coagulating liquid 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 sheet 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, and the treatment related to the drying step may be performed. 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 dryer 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 twin-screw screw type extruder 5 including 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 drying barrels installed in the drying 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 barrel portion 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 where the dehydrated hydrous crumb is dried under reduced pressure. Of the first to eighth drying barrels 54a to 54h constituting the drying barrel portion 54, the second drying barrel 54b, the fourth drying barrel 54d, the sixth drying barrel 54f, and the eighth drying 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 drying barrels 54a to 54h constituting the drying barrel portion 54, the set temperatures in all the drying 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. In the embodiment of the present invention, the shape of the acrylic rubber passing through the die 59 can be extruded into a sheet shape by making the nozzle shape of the die 59 substantially rectangular. 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 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 the 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 of.

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 sheet 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 water spraying 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.

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 blows 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 L1 of the conveyor 61 and the cooling means 65 of the transport type cooling device 60 (the length of the portion where the cooling air can be blown) 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. 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.

Further, the sheet-shaped dry rubber 10 produced by the screw type extruder 5 may be laminated to produce an acrylic rubber veil. 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 each unit 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 sheet or the acrylic rubber veil by the following method.
(1) The amount of carboxyl groups was calculated by dissolving an acrylic rubber sheet or 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 sheet or acrylic rubber veil in methyl ethyl ketone, adding a specified amount of hydrochloric acid 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 sheet or 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 sheet or 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 sheet or acrylic rubber bale ash content is measured by XRF using ZSX Primus (manufactured by Rigaku) by pressing the collected ash content onto a Φ20 mm titration filter paper due to the difference in the above ash content measurement. did.

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

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

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

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

[Molecular weight and molecular weight distribution]
The weight average molecular weight (Mw) and molecular weight distribution ( Mz / Mw) of the acrylic rubber sheet or acrylic rubber bale are such that dimethylformamide has a concentration of 0.05 mol / L of lithium chloride and 0.01% of 37% concentrated hydrochloric acid as a solvent. It is an absolute molecular weight and an absolute molecular weight distribution measured by the GPC-MALS method using the solutions added in. 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 sheet or acrylic rubber bale is temperature-dispersed at a strain of 473% and 1 Hz (40 to 40 to 1 Hz) using a dynamic viscoelasticity measuring device “Rubber Process Analyzer RPA-2000” (manufactured by Alpha Technology). 120 ° C.) was measured, and the complex viscoelasticity η at each temperature was determined. 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 salt 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. Then, 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 the mixture was 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 was 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 was extruded. Then, the sheet-shaped dry rubber was cooled at a cooling rate of 200 ° C./hr by using a transport type cooling device directly connected to the screw type extruder.

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 was cooled to 50 ° C. and then cut with a cutter to produce an acrylic rubber sheet (A). 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 sheet (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, before the temperature of the acrylic rubber sheet (A) becomes 40 ° C. or lower, a plurality of cut acrylic rubber sheets (A) are laminated so as to form 20 parts (20 kg) to obtain an acrylic rubber veil (A). It was. 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.

Using a Bunbury mixer, 100 parts of the acrylic rubber sheet (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 processability of the acrylic rubber sheet was 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 acetate, 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 sheet 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-containing crumb after draining in the first dehydration barrel was changed to 30%. (B) and acrylic rubber bale (B) were 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 sheet (C) and an acrylic rubber bale (C) were 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. The same procedure as in No. 2 was carried out to obtain an acrylic rubber sheet (D) and an acrylic rubber bale (D), 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. The same procedure as above was carried out to obtain an acrylic rubber sheet (E) and an acrylic rubber bale (E), 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 was added, and the mixture was stirred in the coagulation tank at 25 ° C. for 5 minutes, and then the water-containing crumb for discharging water from the coagulation tank was washed four times, and then the sulfuric acid aqueous solution having a pH of 3 194. After adding the portion and stirring at 25 ° C. for 5 minutes, water was discharged from the coagulation tank to perform acid cleaning once, and then 194 parts of pure water was added and pure water cleaning was performed once, and then the cleaning was performed. The water-containing crumb was dried with a hot air dryer at 160 ° C. to obtain a crumb-shaped acrylic rubber (F) having a water 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, the weight average molecular weight (Mw) of the (meth) acrylic acid ester of the present invention as a main component is 100,000 to 5,000,000, and the z average molecular weight (Mz) and the weight average molecular weight (Mw) are Acrylic rubber sheet having a ratio (Mz / Mw) of 1.3 or more, an ash content of 0.2% by weight or less, a specific gravity of 0.8 or more, and a water content of less than 1% by weight. It can be seen that (A) to (E) are remarkably excellent in storage stability and water resistance, and are also excellent in processability (Examples 1 to 5).

From Table 2, when the coagulation liquid was added to the emulsion polymerization solution to generate a hydrous crumb in the coagulation reaction, the amount of ash was contained even if the washing step was performed with water washing four times, acid washing once, and pure water washing once. 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 by washing with warm water twice and the water resistance is reduced. Can be seen to be improved (Reference Example 1). Furthermore, after the solidification reaction is carried out in the same manner, the ash content in the acrylic rubber sheet is reduced and the water resistance is significantly improved by washing twice with warm water and then dehydrating and drying with a screw type extruder. It can be seen that this is done (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 sheets dried by a screw type extruder and molded into sheets have a high specific gravity of 1.0 and contain almost no air, and are remarkably excellent in storage stability. It can be seen that (Examples 1 to 5). This is substantially determined in the dry barrel portion depending on the conditions of the screw type extruder carried out 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. There is little air entrainment due to the fact that it was able to be reliably dried and melt-kneaded to a state where it does not contain moisture, the resin pressure of the die part, the temperature of the extruded sheet-like dry rubber, the temperature of the sheet-like dry rubber during cutting, etc. Large)) It is considered that the acrylic rubber sheet with excellent water resistance could be manufactured by making the acrylic rubber sheet.

From Table 2, the gel amount of the crumb-shaped acrylic rubber obtained by drying the washed hydrous crumb with hot air is large (Comparative Example 1 and Reference Example 1), but the gels of all the acrylic rubber sheets dried by the screw type extruder and sheet-molded. It can be seen that the amount 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 in 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.

Although not shown in the present specification, each characteristic value of the acrylic rubber veil of the present invention in which the acrylic rubber sheet is laminated is the same as the characteristic value of the laminated acrylic rubber sheet.

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

Claims (24)

It has a (meth) acrylic acid ester as a main component and has a reactive group which is at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, and has a weight average molecular weight (Mw) of 100,000 to It is made of acrylic rubber having a z average molecular weight (Mz) and a weight average molecular weight (Mw) ratio (Mz / Mw) of 1.3 or more at 5,000,000, and has an ash content of 0.15 % by weight or less. JIS K6268 Crosslinked rubber- Acrylic rubber sheet with a specific gravity of 0.8 or more and a water content of less than 1% by weight, and a thickness of 1 to 40 mm, as measured according to Method A of density measurement . The acrylic rubber sheet according to claim 1, wherein the amount of at least one element selected from the group consisting of sodium, sulfur, phosphorus, magnesium and calcium in the ash content is 50% by weight or more. The acrylic rubber sheet according to claim 1 or 2, wherein the total amount of sodium and sulfur in the ash is 50% by weight or more. The acrylic rubber sheet according to any one of claims 1 to 3, wherein the complex viscosity ([η] 100 ° C.) at 100 ° C. is in the range of 1,500 to 6,000 Pa · s. The acrylic rubber sheet according to any one of claims 1 to 4, 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 sheet according to any one of claims 1 to 5. The acrylic rubber sheet according to any one of claims 1 to 6, wherein the Mooney viscosity (ML1 + 4,100 ° C.) is in the range of 10 to 150. An emulsion polymerization step in which a monomer component containing (meth) acrylic acid ester as a main component is emulsified with water and an emulsifier and emulsion-polymerized in the presence of a polymerization catalyst to obtain an emulsion polymerization solution.
A coagulation step of adding the obtained emulsion polymerization solution to a coagulation liquid stirred at a peripheral speed of 0.5 m / s or more to generate a hydrous crumb, and
A cleaning process to clean the generated hydrous crumb,
The washed water-containing crumb is dried to a water content of less than 1% by weight 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 a sheet-shaped dry rubber is extruded from the die. A method for manufacturing an acrylic rubber sheet, which includes dehydration, drying, and molding steps. The method for producing an acrylic rubber sheet according to claim 8, wherein the temperature of the hydrous crumb supplied to the screw type extruder is 40 ° C. or higher. The method for producing an acrylic rubber sheet according to claim 8 or 9, wherein the dehydration barrel portion of the screw type extruder squeezes out the water content in the water content crumb to a water content of 1 to 40% by weight. The method for producing an acrylic rubber sheet according to any one of claims 8 to 10, wherein the set temperature of the drying barrel portion of the screw type extruder is in the range of 100 to 250 ° C. The method for manufacturing an acrylic rubber sheet according to any one of claims 8 to 11, wherein the set temperature of the drying barrel portion of the screw type extruder is higher at the outlet portion than at the inlet portion. The method for producing an acrylic rubber sheet according to any one of claims 8 to 12, wherein the degree of decompression of the drying barrel portion of the screw type extruder is in the range of 1 to 50 kPa. The method for producing an acrylic rubber sheet according to any one of claims 8 to 13, wherein the resin pressure of the die portion of the screw type extruder is in the range of 0.1 to 10 MPa. The production of the acrylic rubber sheet according to any one of claims 8 to 14, wherein a cutting step of cutting the sheet-shaped dry rubber extruded from the screw type extruder is provided after the dehydration / drying / molding step. Method. The method for producing an acrylic rubber sheet according to any one of claims 8 to 15, wherein the temperature of the sheet-shaped dry rubber extruded from the screw type extruder is in the range of 100 to 200 ° C. The method for producing an acrylic rubber sheet according to claim 15 , wherein the cutting temperature of the sheet-shaped dry rubber is 60 ° C. or lower. An acrylic rubber veil formed by laminating the acrylic rubber sheets according to any one of claims 1 to 7. A method for producing an acrylic rubber veil, which comprises laminating the acrylic rubber sheet according to any one of claims 1 to 7. The method for producing an acrylic rubber veil according to claim 19, wherein the lamination temperature of the acrylic rubber sheet is 30 ° C. or higher. A rubber mixture obtained by mixing a filler and a cross-linking agent with the acrylic rubber sheet according to any one of claims 1 to 7 or the acrylic rubber veil according to claim 18. A method for producing a rubber mixture, which comprises mixing a filler and a cross-linking agent with the acrylic rubber sheet according to any one of claims 1 to 7 or the acrylic rubber veil according to claim 18 using a mixer. .. A method for producing a rubber mixture in which the acrylic rubber sheet according to claim 1 or the acrylic rubber veil according to claim 18 and a filler are mixed and then a cross-linking agent is mixed according to any one of claims 1 to 7. A rubber crosslinked product obtained by cross-linking the rubber mixture according to claim 21.