JP2021017558A - Acrylic rubber sheet excellent in storage stability and processability - Google Patents

Abstract

To provide an acrylic rubber sheet excellent in storage stability and processability, a method for producing the same, an acrylic rubber bale obtained by laminating the acrylic rubber sheet, a rubber mixture containing the acrylic rubber sheet or the acrylic rubber bale, a method for producing the same, and a rubber crosslinked product thereof.SOLUTION: The acrylic rubber sheet according to the present invention comprises an acrylic rubber having a (meth)acrylic acid ester as a main component and having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and in which the amount of gel insoluble in methyl ethyl ketone is 50 wt.% or less and a liquid antiaging agent is contained.SELECTED DRAWING: None

Description

The present invention relates to an acrylic rubber sheet, a method for producing an acrylic rubber sheet, an acrylic rubber veil, a rubber mixture, and a rubber crosslinked product. More specifically, an acrylic rubber sheet having excellent storage stability and processability and a method for producing the same, the acrylic rubber. The present invention relates to an acrylic rubber bale formed by laminating sheets, a rubber mixture obtained by mixing the acrylic rubber sheet or an acrylic rubber bale, a method for producing the same, and a rubber crosslinked product obtained by cross-linking the acrylic rubber sheets.

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. It is widely used in automobile-related fields and is aged as needed. It is used with the addition of an inhibitor.

For example, Patent Document 1 (International Publication No. 2018/139466 pamphlet) contains pure water, sodium lauryl sulfate, and polyoxy as monomer components containing ethyl acrylate, n-butyl acrylate, monobutyl fumarate, and the like. Stir with ethylene dodecyl ether to obtain a monomeric emulsion, and aqueous ferrous sulfate, sodium alcorbate, and potassium persulfate were continuously added dropwise over 3 hours to achieve an emulsion polymerization rate of 95%. In a solution, a 50% by weight aqueous dispersion of stearyl 3- (3,5-tert-butyl-4-hydroxyphenyl) propionate (0.2% by weight) of an aqueous solution of sodium lauryl sulfate in 50 parts (3,5-). 50 parts by weight of di-tert-butyl-4-hydroxyphenyl) stearyl propionate (added and mixed) or 2,4-bis [(octylthio) methyl] -6-methylphenol 50% by weight aqueous dispersion (0.2) After adding 2,4-bis [(octylthio) methyl] -6-methylphenol (prepared by adding and mixing 50 parts by weight) to 50 parts by weight of an aqueous solution of% by weight of sodium lauryl sulfate, 85 ° C. After the temperature was raised to and solidified with sodium sulfate to generate a hydrous crumb, the resulting hydrous crumb was washed with industrial water four times, acid washed once with pH 3, and then washed with pure water once. Disclosed is a method for producing a crumb-shaped acrylic rubber which can suppress stains on the polymerization apparatus during polymerization by drying at 160 ° C. for 10 minutes in a hot air dryer and has excellent initial mechanical strength. Further, it is described that the hydrous crumb washed with a screw type extruder can be dried at 150 ° C. or higher according to this method. However, in addition to heat resistance, it is required to improve processability and storage stability in a harsh environment.

Regarding the amount of gel of acrylic rubber, for example, Patent Document 2 (Japanese Patent No. 3599962) contains two radically reactive unsaturated groups having different reactivity with 95 to 99.9% by weight of alkyl acrylate or alkoxyalkyl acrylate. Acrylate rubber having a gel content of 5% by weight or less of an acetone-insoluble component obtained by copolymerizing 0.1 to 5% by weight of the above-mentioned polymerizable monomer in the presence of a radical polymerization initiator, reinforcing property. An acrylic rubber composition composed of a filler and an organic peroxide-based vulcanizer and having excellent extrusion processability such as extrusion rate, die well, and surface surface is disclosed. The acrylic rubber used here, which has a very small gel fraction of acetone-insoluble matter, has a gel fraction of acetone-insoluble matter obtained in a normal acidic region (pH 4 before polymerization, pH 3.4 after polymerization). It is obtained by adjusting the polymerization solution to pH 6 to 8 with sodium hydrogen carbonate or the like with respect to acrylic rubber having a high content (60%). Specifically, water, sodium lauryl sulfate and polyoxyethylene nonylphenyl ether as emulsifiers, sodium carbonate and boric acid were added and adjusted to 75 ° C., and then t-butyl hydroperoxide, longalite, disodium ethylenediaminetetraacetate, Ferrous sulfate was added (pH at this time was 7.1), then the monomer components of ethyl acrylate and allyl methacrylate were added dropwise to carry out emulsion polymerization, and the obtained emulsion (pH 7) was subjected to sodium sulfate aqueous solution. Acrylic rubber is obtained by salting using and washing with water and drying. However, acrylic rubber containing (meth) acrylic acid ester as the main component has problems in handling such as decomposition in the neutral to alkaline region and inferior storage stability, and emulsion polymerization is carried out by changing the pH from neutral to alkaline. The acrylic rubber used had a problem of inferior mechanical strength due to the loss of reactive groups (crosslink points) such as carboxyl group, epoxy group and chlorine atom.

Further, in Patent Document 3 (International Publication No. 2018/143101 pamphlet), a (meth) acrylic acid ester and an ion-crosslinkable monomer are emulsion-polymerized and have a complex viscosity at 100 ° C. ([η] 100 ° C.). Is 3,500 Pa · s or less, and the ratio of the complex viscosity at 60 ° C. ([η] 60 ° C.) to the complex viscosity at 100 ° C. ([η] 100 ° C.) ([η] 100 ° C./[η] 60 A technique for improving the extrusion moldability, particularly the discharge amount, the discharge length, and the surface texture of a rubber composition containing a reinforcing agent and a cross-linking agent by using an acrylic rubber having a ° C.) of 0.8 or less is disclosed. The amount of gel of the tetrahydrofuran (THF) insoluble component of acrylic rubber used in the same technique is 80% by weight or less, preferably 5 to 80% by weight, and preferably exists as much as possible in the range of 70% or less. It is stated that the extrudability deteriorates when the amount of gel insoluble in THF is less than 5%. The weight average molecular weight (Mw) of the acrylic rubber used is 200,000 to 1,000,000, and when the weight average molecular weight (Mw) exceeds 1,000,000, the viscoelasticity of the acrylic rubber is high. It is stated that it is too much to be preferable. However, there has been a demand for a highly balanced balance between high strength and workability during kneading such as Banbury, and improvement in storage stability has also been required.

International Publication No. 2018/139466 Pamphlet Japanese Patent No. 3599962 International Publication No. 2018/143101 Pamphlet

The present invention has been made in view of such an actual situation, and an acrylic rubber sheet having excellent storage stability and processability, a method for producing the same, an acrylic rubber bale formed by laminating the acrylic rubber sheets, and the acrylic rubber sheet. Alternatively, it is an object of the present invention to provide a rubber mixture containing an acrylic rubber veil, a method for producing the same, and a rubber crosslinked product thereof.

As a result of diligent research in view of the above problems, the present inventors have obtained a liquid anti-aging agent containing (meth) acrylic acid ester as a main component and composed of acrylic rubber having a specific molecular weight, a specific solvent-insoluble gel amount, and a specific amount of gel. It was found that the acrylic rubber sheet containing it is remarkably excellent in storage stability and workability.

The present inventors also specify the structure and type of the liquid antiaging agent, the molecular weight distribution in the high molecular weight region, the molecular weight, the pH, the specific gravity, the gel amount and the ash content to store and process the acrylic rubber veil. It was found that the sex was further improved.

The present inventors also specify the addition of a liquid anti-aging agent to the emulsion polymerization solution after emulsion polymerization of a monomer component containing (meth) acrylic acid ester as a main component, and the water-containing crumb after washing. After dehydration that squeezes out water to a specific water content with the screw type extruder of, it is dried to a state that does not contain water substantially (specific water content) and extruded sheet-shaped dry rubber to improve storage stability and workability. We have found that we can produce excellent acrylic rubber sheets.

The present inventors also melt-knead a liquid antiaging agent and acrylic rubber in a state where the washed water-containing crumb is dried to a specific water content that is substantially free of water with a specific screw type extruder. It has been found that an acrylic rubber sheet having improved uniform microdispersity and excellent storage stability and heat resistance can be efficiently produced.

In addition, when the polymerization conversion rate of emulsion polymerization is increased in order to improve the strength characteristics of acrylic rubber having a reactive group, the amount of gel insoluble in a specific solvent rapidly increases and the processability deteriorates. However, when the water-containing crumb after cleaning was dried with a screw-type extruder to a state in which it contained virtually no water (specific water volume) and melt-kneaded, the gel amount of the specific solvent-insoluble matter that rapidly increased disappeared and the reaction occurred. We have found that it is possible to produce an acrylic rubber sheet in which strength characteristics, processability, and storage stability are highly balanced without reducing the number of sex groups.

The present inventors have further found that the storage stability and water resistance of the acrylic rubber sheet are highly balanced by squeezing (dehydrating) water from the water-containing crumb after washing to a specific water content.

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

Thus, according to the present invention, it is composed of acrylic rubber containing (meth) acrylic acid ester as a main component and having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and the gel amount of the methyl ethyl ketone insoluble component is 50. Acrylic rubber sheets containing less than% by weight and containing a liquid anti-aging agent are provided.

In the acrylic rubber sheet of the present invention, the content of the liquid anti-aging agent is preferably in the range of 0.001 to 15% by weight.

In the acrylic rubber sheet of the present invention, it is preferable that the liquid anti-aging agent has a hindered structure.

In the acrylic rubber sheet of the present invention, the liquid anti-aging agent is preferably a phenol-based anti-aging agent.

In the acrylic rubber sheet of the present invention, the liquid anti-aging agent is a general formula (1).
(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms.) It is preferable that the hindered phenol-based antiaging agent is represented by.

In the acrylic rubber sheet of the present invention, the ratio (Mz / Mw) of the z average molecular weight (Mz) to the weight average molecular weight (Mw) is preferably 1.3 or more.

In the acrylic rubber sheet of the present invention, the weight average molecular weight (Mw) is preferably 1,000,000 or more.

In the acrylic rubber sheet of the present invention, the pH is preferably 6 or less.

The acrylic rubber sheet of the present invention preferably has a specific gravity of 0.7 or more.

In the acrylic rubber sheet of the present invention, the ash content is preferably 0.5% by weight or less.

According to the present invention, an emulsion polymerization step of emulsifying a metric component containing (meth) acrylic acid ester as a main component with water and an emulsifier and emulsifying and polymerizing in the presence of a polymerization catalyst to obtain an emulsion polymerization solution is obtained. An anti-aging agent addition step of adding a liquid anti-aging agent to the emulsion polymerization solution, a coagulation step of bringing the emulsion polymerization solution to which the liquid anti-aging agent was added into contact with the coagulation liquid to generate a hydrous crumb, and the produced hydrous crumb. The washing step of washing and the washed water-containing crumb are dehydrated to a water content of 1 to 40% by weight in the dehydration barrel using a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip. A method for producing an acrylic rubber sheet is provided, which comprises a step of dehydration, drying, and molding in which a sheet-shaped dried rubber is extruded from a die after being dried in a drying barrel to a water content of less than 1% by weight.

In the method for producing an acrylic rubber sheet of the present invention, the polymerization conversion rate of emulsion polymerization is preferably 90% by weight or more.

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 in which the acrylic rubber sheet is laminated.

In the method for producing an acrylic rubber veil 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 reinforcing agent 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 reinforcing agent and a cross-linking agent with the acrylic rubber sheet or the acrylic rubber veil with a mixer.

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

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

According to the present invention, an acrylic rubber sheet having excellent storage stability and processability and a method for producing the same, an acrylic rubber bale formed by laminating the acrylic rubber sheet, and a rubber mixture obtained by mixing the acrylic rubber sheet or the acrylic rubber bale. And a method for producing the same, and a rubber crosslinked product obtained by cross-linking the same.

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 is composed of acrylic rubber containing (meth) acrylic acid ester as a main component and having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and has a gel amount of methyl ethyl ketone insoluble matter. It is characterized by containing 50% by weight or less and a liquid anti-aging agent.

<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.

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.

As the acrylic rubber constituting the acrylic rubber sheet of the present invention, one containing a reactive group-containing monomer is suitable because it 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 particularly limited, but usually has a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms, preferably an alkyl having 1 to 8 carbon atoms (meth). ) Acrylic acid alkyl ester, more preferably a (meth) acrylic acid alkyl ester having an alkyl group having 2 to 6 carbon atoms.

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

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

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

These (meth) acrylic acid esters are used alone or in combination of two or more, and the proportion in the acrylic rubber is usually 50% by weight or more, preferably 70 to 99.9% by weight, more preferably 80. ~ 99.5% by weight, most preferably 87-99% by weight. If the amount of (meth) acrylic acid ester in the monomer component is excessively small, the weather resistance, heat resistance, and oil resistance of the obtained acrylic rubber may decrease, which is not preferable.

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

The monomer having a carboxyl group is not particularly 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 permanent strain property when the acrylic rubber is used as a rubber crosslinked product.

The ethylenically unsaturated monocarboxylic acid is not particularly 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, etc. Examples thereof include crotonic acid.

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, citraconic acid, and chloro. Maleic acid and the like can be mentioned. The ethylenically unsaturated dicarboxylic acid includes those existing as an anhydride.

The ethylenically unsaturated dicarboxylic acid monoester is not particularly 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 4 to 6 carbon atoms. Ethylene 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.

Specific examples of the ethylenically unsaturated dicarboxylic acid monoester include monomethyl fumarate, monoethyl fumarate, mono n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono n-butyl maleate, monocyclopentyl fumarate, and fumarate. Butendionic acid monoalkyl esters such as monocyclohexyl acid, monocyclohexenyl fumarate, monocyclopentyl maleate, and monocyclohexyl maleate; Examples thereof include monoalkyl esters; 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.

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.

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

The other monomer used as needed is not particularly limited as long as it can be copolymerized with the above-mentioned monomer. For example, aromatic vinyl, ethylenically unsaturated nitrile, acrylamide-based monomer, and the like. Olefin-based monomers and the like. Examples of 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 is composed of the above-mentioned monomer components and preferably has a reactive group.

The reactive group is appropriately selected depending on the intended use without any particular limitation, but preferably at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a halogen group, more preferably a carboxyl group. When it is a base, it is suitable because the crosslinked property of the acrylic rubber sheet can be highly improved. Further, as the reactive group, when it is an ionic reactive group such as a carboxyl group or an epoxy group, the water resistance can be particularly improved, which is preferable. 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 characteristics, compressive permanent strain resistance, oil resistance, when in the range of 0.01 to 3% by weight, particularly preferably 0.05 to 1% by weight, most preferably 0.1 to 0.5% by weight. It is suitable because the characteristics such as cold resistance and water resistance are highly balanced.

Specific examples of the acrylic rubber constituting the acrylic rubber sheet of the present invention include a (meth) acrylic acid ester, a reactive group-containing monomer, and, if necessary, other copolymerizable monomers. The proportion of (meth) acrylic acid 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 particularly preferably 87 to 99% by weight. The content 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 to 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 there. By setting these monomers of acrylic rubber in this range, the object of the present invention can be highly achieved, and when the acrylic rubber sheet is used as a crosslinked product, water resistance and compression resistance permanent strain characteristics are remarkably improved, which is suitable. is there.

The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber sheet of the present invention is an absolute molecular weight measured by GPC-MALS, which is 100,000 to 5,000,000, preferably 500,000 to 4,000. Workability, strength characteristics, and strength characteristics of the acrylic rubber sheet when mixed when it is in the range of 000, more preferably 700,000 to 3,000,000, and most preferably 1,000,000 to 2,500,000. It is suitable because the compression resistance permanent strain characteristics are highly balanced. Further, the weight average molecular weight (Mw) of acrylic rubber is usually 1,000,000 or more, preferably 1,000, when the strength characteristics are particularly emphasized and the workability and the compression resistance permanent strain characteristics are highly balanced. 000 to 5,000,000, more preferably 1,000,000 to 4,000,000, particularly preferably 1,100,000 to 3,000,000, most preferably 1,200,000 to 2,500 It is in the range of 000.

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 sheet of the present invention is not particularly limited, but is measured by GPC-MALS. Absolute molecular weight distribution focusing on the polymer region, usually in the range of 1.3 or more, preferably 1.4 to 5, more preferably 1.5 to 2, and the processability and strength characteristics of the acrylic rubber sheet. Is highly balanced and is suitable because it can alleviate changes in physical properties during storage.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber sheet of the present invention is not particularly limited, but is absolutely measured by GPC-MALS. When the molecular weight distribution is usually in the range of 1.1 to 8, preferably 1.2 to 7, and more preferably 1.4 to 6, the processability, strength characteristics, and compression set resistant permanent strain characteristics of the acrylic rubber sheet are high. It is well-balanced and suitable.

The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber sheet of the present invention is not particularly limited, but is usually 20 ° C. or lower, preferably 10 ° C. or lower, and more preferably 0 ° C. or lower. The lower limit of the glass transition temperature (Tg) of acrylic rubber is not particularly limited, but is usually −80 ° C. or higher, preferably −60 ° C. or higher, and more preferably −40 ° C. or higher. By setting the glass transition temperature to the lower limit or higher, the oil resistance and heat resistance can be improved, and by setting the glass transition temperature to the 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 depending on the intended use, but is usually 85% by weight or more, preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 95% by weight or more. It is 97% by weight or more, most preferably 98% by weight or more.

<Containing anti-aging agent>
The acrylic rubber sheet of the present invention is characterized by containing a liquid anti-aging agent. As the liquid anti-aging agent, any of the commonly used anti-aging agents that are liquid can be used without any particular limitation. The "liquid" of the liquid anti-aging agent is not particularly limited, but usually refers to a liquid form at a normal pressure of 40 ° C. or lower.

The melting point of the liquid anti-aging agent used is not particularly limited, but is usually 40 ° C. or lower, preferably 35 ° C. or lower, more preferably 30 ° C. or lower, and the storage stability and heat resistance of the acrylic rubber sheet. Can be remarkably improved, which is preferable. The lower limit of the melting point of the liquid anti-aging agent is not particularly limited, but the storage stability of the acrylic rubber sheet is usually -40 ° C or higher, preferably -20 ° C or higher, more preferably 0 ° C or higher. It is also excellent in heat resistance and bleeding property of liquid anti-aging agent, which is suitable.

The molecular weight of the liquid anti-aging agent used is not particularly limited, but is usually acrylic when it is in the range of 100 to 800, preferably 120 to 600, more preferably 150 to 500, and particularly preferably 200 to 400. It is suitable because it can highly improve the storage stability and heat resistance of the rubber sheet.

The type of liquid anti-aging agent used is not particularly limited, but for example, phenol-based anti-aging agent, phosphite ester-based anti-aging agent, sulfur ester-based anti-aging agent, amine-based anti-aging agent, imidazole-based anti-aging agent. Examples thereof include agents, quinoline-based anti-aging agents, and hydroquinone-based anti-aging agents. Among these, phenol-based anti-aging agents are suitable because they can highly improve the storage stability and heat resistance of acrylic rubber sheets.

The structure of the liquid anti-aging agent used is not particularly limited, but it is suitable because it can highly improve the storage stability and heat resistance of the acrylic rubber sheet when it has a hindered structure. The compound having a hindered structure is not particularly limited as long as it is a liquid antioxidant having a hindered structure, but is preferably a liquid hindered phenolic antioxidant. The hindered phenolic anti-aging agent refers to an agent having a bulky substituent on the carbon atom on both sides of the aromatic ring carbon atom having an OH group.

Examples of such a suitable liquid hindered phenolic antiaging agent include the general formula (1).
(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms.) Examples thereof include hindered phenolic antiaging agents.

R1 in the formula represents an isopropyl group or a t-butyl group, and is preferably a t-butyl group. R2 in the formula represents an alkyl group having 1 to 12 carbon atoms, preferably an alkyl group having 4 to 10 carbon atoms, and more preferably an alkyl group having 6 to 10 carbon atoms.

Specific examples of the phenolic antioxidant represented by the general formula (1) include butyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate and 3- (4-hydroxy-3). , 5-Di-tert-butylphenyl) hexyl propionate, 3- (4-hydroxy-3,5-di-tert-butylphenyl) octyl propionate, 3- (4-hydroxy-3,5-di-tert) -Decil butylphenyl) propionate, heptyl 3- (4-hydroxy-3,5-diisopropylphenyl) propionate, octyl 3- (4-hydroxy-3,5-diisopropylphenyl) propionate, 3- (4-hydroxy) Dodecyl -3,5-diisopropylphenyl) propionate and the like, preferably octyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate or 3- (4-hydroxy-3, It is octyl 5-diisopropylphenyl) propionate, more preferably octyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate.

Examples of the hindered phenol-based antiaging agent other than the above general formula (1) include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, and 2,6. -Di-t-butyl-α-dimethylamino-p-cresol and the like can be mentioned.

Examples of phenolic antioxidants other than hindered phenolic antioxidants include styrene phenols such as butyl hydroxyanisole, mono (or di or tri) (α-methylbenzyl) pheonol, and 2,2'. -Methylene-bis (6-α-methyl-benzyl-p-cresol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), alkylated bisphenol, 2,4-bis [(octylthio) ) Methyl] -6-methylphenol, 2,2'-thiobis- (4-methyl-6-t-butylphenol), 4,4'-thiobis- (6-t-butyl-o-creso) and the like. , Preferably 2,4-bis [(octylthio) methyl] -6-methylphenol.

Various anti-aging agents for rubber are already on the market, and a list of these products can be found on pages 436 to 443 (Table 5-16) of the "Rubber Industry Handbook (4th Edition)". Although it is described, in the present invention, among the antiaging agents listed in the same table, those in a liquid form may be used.

These liquid anti-aging agents can be used alone or in combination of two or more, and the content in the acrylic rubber sheet is appropriately selected within the range in which the effects of the present invention can be exhibited without any particular limitation. However, it is usually in the range of 0.001 to 15% by weight, preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, and particularly preferably 0.5 to 3% by weight. ..

The acrylic rubber sheet of the present invention is essential to contain a liquid anti-aging agent, but other anti-aging agents can be contained as long as the object of the present invention is not impaired.

<Acrylic rubber sheet>
The acrylic rubber sheet of the present invention is characterized by being made of the acrylic rubber, containing the above-mentioned anti-aging agent, and specifying the amount of gel of the methyl ethyl ketone insoluble component.

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. , Storage stability and productivity are highly balanced and suitable. 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 appropriately selected depending on the intended use, but is particularly excellent in handleability and suitable when it is usually in the range of 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm. Is.

The length of the acrylic rubber sheet of the present invention is not particularly limited, but is particularly excellent and suitable when it is usually in the range of 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm. is there.

The gel amount of the acrylic rubber sheet of the present invention is the insoluble content of methyl ethyl ketone, which is 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, and most preferably 5. When it is less than% by weight, the workability is highly improved and is suitable. The amount of gel, which is the insoluble matter of methyl ethyl ketone in the acrylic rubber veil, is related to the processability at the time of kneading such as Banbury, but the characteristics of the amount of gel differ depending on the solvent used, and in particular, THF (tetrahydrofuran) is insoluble. It did not correlate with the amount of gel in.

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

The water content of the acrylic rubber sheet of the present invention 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. Is optimized and has excellent properties such as heat resistance and water resistance, which is suitable.

The ash content of the acrylic rubber sheet of the present invention is. Although not particularly limited, it is usually 0.5% by weight or less, preferably 0.3% by weight or less, more preferably 0.2% by weight or less, particularly preferably 0.15% by weight or less, and most preferably 0. When it is .13% by weight or less, it is excellent in storage stability and water resistance and is suitable.

The lower limit of the ash content of the acrylic rubber sheet of the present invention is not particularly limited, but is usually 0.0001% by weight or more, preferably 0.0005% by weight or more, and more preferably 0.001% by weight or more. Particularly preferably, when it is 0.005% by weight or more, and most preferably 0.01% by weight or more, metal adhesion is suppressed and workability is excellent.

The amount of ash in which the storage stability, water resistance and metal adhesion of the acrylic rubber sheet of the present invention are highly balanced is not particularly limited, but is usually 0.0001 to 0.5% by weight, preferably 0. In the range of 0005 to 0.5% by weight, more preferably 0.001 to 0.2% by weight, particularly preferably 0.005 to 0.15% by weight, and most preferably 0.01 to 0.13% by weight. is there.

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

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, as a ratio to the total ash content. % Or more, particularly preferably 80% by weight or more, the storage stability and water resistance 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 a weight ratio and is not particularly limited, but is usually 0.4 to 2.5, preferably 0. When it is in the range of .6 to 2, preferably 0.8 to 1.7, and more preferably 1 to 1.5, the water resistance is highly excellent and suitable.

The total amount of magnesium and phosphorus 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, as a ratio to the total ash content. % Or more, particularly preferably 80% by weight or more, the storage stability and water resistance are highly excellent and suitable.

The ratio of magnesium to phosphorus ([Mg] / [P]) in the ash content of the acrylic rubber sheet of the present invention is a weight ratio and is not particularly limited, but is usually 0.4 to 2.5, preferably 0. Storage stability and water resistance are in the range of .4 to 1.3, more preferably 0.4 to 1, particularly preferably 0.45 to 0.75, and most preferably 0.5 to 0.7. Highly excellent and 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 2,500 to 7,000 Pa · s, and most preferably 2,700 to 5,500 Pa · s, which is excellent in processability, oil resistance and shape retention.

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 it is in the range of 000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s, it is excellent in processability, oil resistance, and shape retention. ..

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 0.5 or more, preferably 0.6 to 0.98, more preferably 0.75 to 0.95, particularly preferably 0.8 to 0.94, and most preferably 0. When the range is in the range of .83 to 0.93, workability, oil resistance, and shape retention are highly balanced and suitable.

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

<Manufacturing method of acrylic rubber sheet>
The method for producing the acrylic rubber sheet of the present invention is not particularly limited, but for example, a weight component containing (meth) acrylic acid ester as a main component is emulsified with water and an emulsifier in the presence of a polymerization catalyst. An emulsion polymerization step of emulsifying and polymerizing to obtain an emulsion polymerization solution, an antiaging agent addition step of adding a liquid antiaging agent to the obtained emulsion polymerization solution, and an emulsion polymerization solution to which a liquid antiaging agent is added are brought into contact with a coagulating solution. A solidification step to generate a hydrous crumb, a cleaning step to clean the produced hydrous crumb, and a screw type extruder having a dehydration barrel with a dehydration slit, a drying barrel under reduced pressure, and a die at the tip of the cleaned hydrous crumb. It is easy to include the dehydration, drying, and molding steps of dehydrating to a moisture content of 1 to 40% by weight in a dehydration barrel, drying to a moisture content of less than 1% by weight in a drying barrel, and extruding a sheet-shaped dry rubber from the die. Can be manufactured in.

(Emulsion polymerization process)
In the emulsion polymerization step in the method for producing an acrylic rubber sheet of the present invention, a weight component containing a (meth) acrylic acid ester and a reactive group-containing monomer is emulsified with water and an emulsifier and emulsion-polymerized in the presence of a polymerization catalyst. It is characterized in that an emulsion polymerization solution is emulsified with water and an emulsifier and emulsion polymerization is carried out in the presence of a polymerization catalyst to obtain an emulsion polymerization solution.

The monomer component used is the same as that described in the monomer component, and the amount used may be appropriately selected so as to have the monomer composition of the acrylic rubber constituting the acrylic rubber sheet. Often, the amount is usually the same as the monomer composition of the acrylic rubber constituting the acrylic rubber sheet.

The emulsifier used is not particularly limited, and examples thereof include an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier, and the like, preferably containing an anionic emulsifier, and particularly preferably a sulfate ester. It contains a salt and a phosphate ester salt, and most preferably contains a phosphate ester salt.

The anionic emulsifier is not particularly limited, for example, salts of fatty acids such as myristic acid, palmitic acid, oleic acid and linolenic acid; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sulfate esters such as sodium lauryl sulfate. Phosphate ester salts such as salts and polyoxyalkylene alkyl ether phosphate ester salts; alkyl sulfosuccinates and the like can be mentioned. Among these anionic emulsifiers, phosphate ester salts and sulfate ester salts are preferable, and phosphate ester salts are particularly preferable. Suitable phosphate salts include, for example, sodium lauryl phosphate, potassium lauryl phosphate, sodium polyoxyalkylene alkyl ether phosphate and the like. Further, examples of suitable sulfate ester salts include sodium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkyl sulfate, sodium polyoxyethylene alkylaryl sulfate, and the like. Sodium lauryl sulfate is particularly suitable. These anionic emulsifiers can be used alone or in combination of two or more.

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

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; and a polyoxy such as polyoxyethylene nonylphenyl ether. Alkylene alkylphenol ethers; polyoxyethylene sorbitan alkyl esters and the like can be mentioned, with polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenol ethers being preferred, and polyoxyethylene alkyl ethers and polyoxyethylene alkyl phenol ethers being more preferred.

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, with respect to 100 parts by weight of the monomer component. It is in the range of 1 to 5 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 is not particularly limited as long as it is usually used in emulsion polymerization, and for example, a redox catalyst composed of a radical generator and a reducing agent can be used.

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

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

The organic peroxide is not particularly limited as long as it is a known organic peroxide used in emulsion polymerization. For example, 2,2-di (4,5-di- (t-butylperoxy) cyclohexyl) propane. , 1-di- (t-hexyl peroxy) cyclohexane, 1,1-di- (t-butyl peroxy) cyclohexane, 4,4-di- (t-butyl peroxy) n-butyl valerate, 2, 2-Di- (t-butylperoxy) butane, t-butylhydroperoxide, cumenehydroperoxide, diisopropylbenzenehydroperoxide, paramentanhydroperoxide, benzoyl peroxide, 1,1,3,3-tetraethyl Butylhydroperoxide, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, diisobutyryl peroxide , Di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disuccinic acid peroxide, dibenzoyl peroxide, di (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide , Diisobutyryl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, 1,1,3,3-tetramethylbutyl Peroxyneodecanate, t-hexylperoxypivarate, t-butylperoxyneodecanate, t-hexylperoxypivarate, t-butylperoxypivarate, 2,5-dimethyl-2,5-di (2-Ethylhexanoylperoxy) hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-3 , 5,5-trimethylhexanate, t-hexyl peroxyisopropyl monocarbonate, t-butylperoxyisopropyl monocarbonate, t-buylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5- Di (benzoylperoxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di ( Examples thereof include t-butylperoxy) hexane, 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 (Propane-2-carboamidine), 2,2'-Azobis [N- (2-carboxyethyl) -2-methylpropaneamide], 2,2'-Azobis {2- [1- (2- (2-) Hydroxyethyl) -2-imidazolin-2-yl] propane}, 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) and 2,2'-azobis {2-methyl-N- [ 1,1-bis (hydroxymethyl) -2-hydroxyethyl] propanamide} and the like.

Each of these radical generators can be used alone or in combination of two or more, and the amount used is usually 0.0001 to 5 parts by weight, preferably 0.0001 to 5 parts by weight, based on 100 parts by weight of the monomer component. It is in the range of 0.0005 to 1 part by weight, more preferably 0.001 to 0.5 part by weight.

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

The metal ion compound in the reduced state is not particularly limited, and examples thereof include ferrous sulfate, sodium hexamethylenediamine tetraacetate, and cuprous naphthenate, 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.

The reducing agent other than the metal ion compound in the reduced state is not particularly limited, but is, for example, ascorbic acid such as ascorbic acid, sodium ascorbate, potassium ascorbate or a salt thereof; erythorbic acid, sodium erythorbicate, erythorbin. Elysorbic acid such as potassium acid or a salt thereof; sulphinate such as sodium hydroxymethane sulfite; sodium sulfite, potassium sulfite, sodium hydrogen sulfite, aldehyde sodium bisulfite, potassium hydrogen sulfite sulfite; sodium pyrosulfite, potassium pyrosulfite Pyro sulfites such as sodium bisulfite and potassium hydrogen pyrosulfite; thiosulfates such as sodium thiosulfite and potassium thiosulfite; of sodium bisulfite, sodium bisulfite, potassium bisulfite, sodium hydrogen phosphite, potassium hydrogen phosphite Pyrophosphoric acid or a salt thereof; pyroaphosphate or a salt thereof such as pyrophosphate, sodium pyrophosphate, potassium pyrophosphate, sodium bisulfite, potassium hydrogenpyrophosphate and the like; sodium formaldehyde sulfoxylate and the like. 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 preferred combination of the reducing metal ion compound and the other reducing agent is ferrous sulfate and ascorbic acid or a salt thereof and / or sodium formaldehyde sulfoxylate, more preferably ferrous sulfate and ascorbate. And / or sodium formaldehyde sulfoxylate, most preferably a combination of ferrous sulfate and alcorbate. At this time, the amount of ferrous sulfate used is usually 0.000001 to 0.01 parts by weight, preferably 0.00001 to 0.001 parts by weight, more preferably 0.00001 parts by weight, based on 100 parts by weight of the monomer component. In the range of 0.00005 to 0.0005 parts by weight, the amount of ascorbic acid or a salt thereof and / or sodium formaldehyde sulfoxylate used is usually 0.001 to 1 part by weight 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 one used at the time of emulsification of the monomer component, but is usually 10 to 1000 parts by weight, preferably 50 parts by weight, based on 100 parts by weight of the monomer component used for polymerization. It is adjusted to be in the range of ~ 500 parts by weight, more preferably 80 to 400 parts by weight, and most preferably 100 to 300 parts by weight.

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

The polymerization conversion rate of the emulsion polymerization reaction is not particularly limited, but is excellent in the strength characteristics of the acrylic rubber sheet usually produced when it is usually 80% by weight or more, preferably 90% by weight or more, and more preferably 95% by weight or more. Moreover, there is no monomeric odor and it is suitable. A polymerization inhibitor may be used to terminate the polymerization.

(Anti-aging agent addition process)
The antiaging agent addition step in the method for producing an acrylic rubber sheet of the present invention is characterized in that a liquid antiaging agent is added to the emulsion polymerization solution after the emulsion polymerization.

The liquid anti-aging agent used is the same as that described in the above-mentioned contained anti-aging agent, and the amount used may be appropriately selected so as to be the content of the acrylic rubber sheet, and the monomer component 100 With respect to parts by weight, it is usually 0.001 to 15 parts by weight, preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, particularly preferably 0.3 to 3 parts by weight, most preferably. It is in the range of 0.5 to 2 parts by weight.

The method of adding the liquid anti-aging agent to the emulsion polymerization solution is not particularly limited and may follow a conventional method. The liquid anti-aging agent may be added as it is, or it may be emulsified with water and an emulsifier and added. Good.

(Coagulation process)
The coagulation step in the method for producing an acrylic rubber sheet of the present invention is a step of bringing the emulsion polymerization solution to which the liquid antiaging agent is added into contact with the coagulation liquid to form a hydrous crumb.

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

The coagulant used is not particularly limited, but 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 Group 2 of the Periodic Table. A metal salt, particularly preferably a magnesium salt.

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

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

Other metal salts include, for example, zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, tin chloride, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate. , Aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, tin sulfate and the like.

Each of these coagulants can be used alone or in combination of two or more, and the amount used is usually 0.01 to 100 parts by weight, preferably 0, with respect to 100 parts by weight of the monomer component. It is in the range of 1 to 50 parts by weight, more preferably 1 to 30 parts by weight. When the coagulant is in this range, it is preferable because the acrylic rubber can be sufficiently coagulated, and the compression set resistance and water resistance when the acrylic rubber sheet is crosslinked can be highly improved.

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

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

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

The stirring speed (rotation speed) of the coagulated liquid being stirred is, that is, the rotation speed of the stirring blade of the stirring device, and is not particularly limited, but is usually 100 rpm or more, preferably 200 to 1000 rpm, and more preferably 300 to 900 rpm. , Especially preferably in the range of 400 to 800 rpm.

It is preferable that the rotation speed is a rotation speed in which the mixture is vigorously agitated to some extent so that the water-containing crumb particle size to be generated can be made small and uniform. The formation of and can be suppressed, and the solidification reaction can be more easily controlled by setting the content to the upper limit or less.

The peripheral speed of the coagulated liquid being agitated, that is, the speed of the outer circumference of the stirring blade of the agitating device is not particularly limited, but the water-containing crumb particle size generated by being vigorously agitated to a certain degree is smaller and It can be made uniform and is preferable, 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. On the other hand, the upper limit of the peripheral speed is not particularly limited, but usually solidifies 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. It is suitable because the reaction can be easily controlled.

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

(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 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 monomer component. The amount of ash in the acrylic rubber sheet can be effectively reduced, preferably in the range of 100 to 10,000 parts by weight, particularly preferably in the range of 150 to 5,000 parts by weight.

The temperature of the water to be washed with water is not particularly limited, but it is preferable to use warm water, which is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C., and most preferably 60 to 60 ° C. It is suitable because the cleaning efficiency can be remarkably increased at 80 ° C.

By setting the temperature of the washing water to the above lower limit or higher, the emulsifier and the coagulant are released from the water-containing crumb, and the washing efficiency is further improved.

The washing time is not particularly 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 not particularly limited, and 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 times of washing with water is large, but the shape and diameter of the water-containing crumb should be specified and / Alternatively, the number of cleanings can be significantly reduced by setting the cleaning temperature within the above range.

(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 water-containing crumb is subjected to a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip. It is characterized by dehydrating to a water content of 1 to 40% by weight in a dehydration barrel and then drying to less than 1% by weight in a drying barrel to extrude a sheet-shaped dry rubber from a die.

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

Draining step In the method for producing an acrylic rubber sheet of the present invention, it is necessary to provide a draining step for separating free water from the water-containing crumb after washing with a draining machine after the washing step and before the dehydration / drying step to improve the dehydration efficiency. It is suitable for raising.

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

The opening of the drainer is not particularly limited, but when it is usually in the range of 0.01 to 5 mm, preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm, the water content crumb loss occurs. It is suitable because it can be drained efficiently with a small amount.

The water content of the water-containing crumb after draining, that is, the water content of the water-containing crumb put into 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. It is suitable because difficult hydrous crumbs can be efficiently dehydrated and dried using a screw type extruder.

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

The number of dehydration barrels in the screw extruder is not particularly limited, but usually a plurality, preferably 2 to 10, more preferably 3 to 6, is used to dehydrate the adhesive acrylic rubber. It is suitable for efficient operation.

There are two ways to remove water from the water-containing crumb in the dehydration barrel: one that removes water from the dehydration slit in liquid form (drainage) and one that removes water in the form of steam (exhaust vapor). 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 (dehydration) and steam (preliminary drying) to efficiently remove water from the adhesive acrylic rubber. The selection of the drainage type dehydration barrel or the exhaust steam type dehydration barrel of the screw type extruder equipped with three or more dehydration barrels may be appropriately performed according to the purpose of use, but the amount of ash in the acrylic rubber sheet usually produced is determined. To reduce the amount, increase the number of drainage barrels, and to reduce the water content, increase the number of exhaust steam type barrels.

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

The water content after dehydration of the drainage type dehydration that squeezes water from the water-containing crumb is not particularly limited, but is usually 1 to 45% by weight, preferably 1 to 40% by weight, more preferably 5 to 35% by weight, particularly. When it is preferably 10 to 35% by weight, most preferably 15 to 35% by weight, productivity and ash removal efficiency are highly balanced and preferable.

When dehydration of adhesive acrylic rubber is performed using a centrifuge or the like, acrylic rubber adheres to the dehydration slit portion and is hardly dehydrated (water content is up to about 45 to 55% by weight), but in the present invention. By using a screw type extruder that has a dehydration slit and is forcibly squeezed with a screw, the water content can be reduced to this extent.

In the case of providing the drainage type dehydration barrel and the exhaust steam type dehydration barrel, the water content after dehydration in the drainage type dehydration barrel portion is usually 5 to 45% by weight, preferably 10 to 40% by weight, more preferably. Is 15 to 35% by weight, and the water content after pre-drying in the exhaust steam type dehydration barrel portion is usually 1 to 30% by weight, preferably 3 to 20% by weight, and more preferably 5 to 15% by weight.

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

Drying of hydrous crumb (dry barrel)
The hydrous crumb after dehydration is dried in a drying barrel portion under reduced pressure.

The degree of decompression of the drying barrel may be appropriately selected, but it is preferable that the hydrous crumb can be efficiently dried when it is usually 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa.

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

The number of drying barrels in the screw type extruder is not particularly limited, but is usually a plurality, preferably 2 to 10 barrels, and 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. When there are multiple drying barrels, the set temperature may be an approximate temperature for all the drying barrels or may be changed, but it is closer to the discharge part (closer to the die) than the temperature of the introduction part (closer to the dehydration barrel). It is preferable that the temperature of (1) is higher because the drying efficiency can be increased.

The water content of the dried rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. In the present invention, the liquid anti-aging agent and acrylic rubber are melt-kneaded and extruded at this value (a state in which almost all water is removed), especially in a screw-type extruder, so that storage stability and heat resistance are achieved. Acrylic rubber sheets with highly improved properties can be manufactured, which is suitable. In the present invention, the amount of gel in the methyl ethyl ketone insoluble portion of the acrylic rubber sheet can be reduced and the processability of the acrylic rubber sheet can be remarkably improved by melt-kneading the acrylic rubber with almost all water removed. Suitable.

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 the rectifying die portion without a screw. A breaker plate or wire mesh may or may not be provided between the screw portion and the die portion.

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

The resin pressure in the die portion is not 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 (high specific gravity). Moreover, it is 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 3000 to 15000 mm, preferably 4000 to 10000 mm, and more preferably 4500. The range is ~ 8000 mm.

The screw diameter (D) of the screw type extruder used 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 less than 1% by weight without lowering the molecular weight or burning of the dried rubber when it is in the range of 30 to 60.

The rotation speed (N) of the screw type extruder used may be appropriately selected according to various conditions, but is usually 10 to 1000 rpm, preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120. When the speed is ~ 300 rpm, the water content of acrylic rubber and the gel amount of the insoluble methyl ethyl ketone can be efficiently reduced, which is preferable.

The extrusion amount (Q) of the screw type extruder used is not particularly limited, but is usually 100 to 1,500 kg / hr, preferably 300 to 1200 kg / hr, more preferably 400 to 1000 kg / hr, and most preferably 500. It is in the range of ~ 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, more preferably. Is in the range of 4-6.

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 usually cooled and cut to be 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 depending on the intended use, but is usually in the range of 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm.

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 particularly limited, but is usually 1,500 to 6,000 Pa · s, preferably 2. Extrudability and shape retention as a sheet when it is in the range of 5,000 to 5,000 Pa · s, more preferably 2,500 to 4,000 Pa · s, and most preferably 2,500 to 3,500 Pa · s. Is highly balanced and suitable. That is, when it is set to the lower limit or more, the extrudability can be improved, and when it is set 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 usually it can be cut and used.

The cutting of the sheet-shaped dry rubber is not particularly limited, but since the acrylic rubber of the acrylic rubber sheet of the present invention has strong adhesiveness, the sheet-shaped dry rubber is used in order to continuously cut without entraining air. It is preferable to cool it down.

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

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

The ratio of the complex viscosity at 100 ° C. ([η] 100 ° C.) to the complex viscosity at 60 ° C. ([η] 60 ° C.) ([η] 100 ° C./[η] 60 ° C.) of the sheet-shaped dry rubber is Although not particularly limited, it is usually 0.5 or more, preferably 0.6 to 0.98, more preferably 0.75 to 0.95, particularly preferably 0.8 to 0.94, and most preferably 0.83. When the range is in the range of ~ 0.93, the air entrainment property is low, and cutting and productivity are highly balanced, which is preferable.

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

In the air-cooled method of sheet-shaped dry rubber, for example, the sheet-shaped dry rubber can be extruded from a screw-type extruder onto a conveyor such as a belt conveyor, and can be conveyed and cooled while blowing cold air. The temperature of the cold air is not 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 it is particularly easy to cut 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 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, storage stability, and heat resistance 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 in that the acrylic rubber sheets are laminated. 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 1200 mm. The height is usually in the range of 400 to 1000 mm, more preferably 500 to 800 mm, and the height is usually in the range of 50 to 500 mm, preferably 100 to 300 mm, more preferably 150 to 250 mm.

Reactive group content, monomer composition, weight average molecular weight (Mw), ratio of z average molecular weight (Mz) to weight average molecular weight (Mw) (Mz / Mw) of acrylic rubber constituting the acrylic rubber veil of the present invention. ), The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and the glass transition temperature (Tg) are the same as the characteristic values of each of the acrylic rubbers constituting the acrylic rubber sheet. ..

Reactive group content, liquid anti-aging agent content, water content, ash content, component content and ratio in ash, specific gravity, gel amount of methyl ethyl ketone insoluble content, pH, complex viscosity at 60 ° C. of the acrylic rubber veil of the present invention. Rate ([η] 60 ° C), complex viscosity at 100 ° C ([η] 100 ° C), complex viscosity at 100 ° C ([η] 100 ° C) and complex viscosity at 60 ° C ([η] 60 ° C) The characteristic values of the ratio ([η] 100 ° C./[η] 60 ° C.) and the Mooney viscosity (ML1 + 4,100 ° C.) are the same as the respective characteristic values of the acrylic rubber sheet.

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

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 veil.

The acrylic rubber veil of the present invention thus obtained is superior in operability, storage stability and water resistance 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, roll, etc. It can be used by putting it in a mixer.

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

The filler is not particularly limited, and examples thereof include a reinforcing filler and a non-reinforcing filler, and a reinforcing filler is preferable.

Examples of the reinforcing filler include carbon black such as furnace black, acetylene black, thermal black, channel black, and graphite; silica such as wet silica, dry silica, and colloidal silica; and the like. Examples of the non-reinforcing filler include quartz powder, silica soil, zinc oxide, basic magnesium carbonate, active calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, barium sulfate and the like. be able to.

These fillers can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the effect of the present invention, and 100 parts by weight of the acrylic rubber sheet or the acrylic rubber veil is selected. On the other hand, it is usually in the range of 1 to 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 can cross-link the acrylic rubber sheet or the acrylic rubber bale. If this is the case, the present invention is not particularly limited, and 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 to be used is composed of a carboxyl group-containing acrylic rubber, it is preferable to use a polyvalent amine compound and a carbonate thereof as a cross-linking agent. Examples of the polyvalent amine compound 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; 4, Aromatic polyvalent amine compounds such as 4'-methylenedianiline; 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; A quaternary onium salt such as cetyltrimethylammonium 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, ammonium carboxylic acid salt and 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.

Each of these cross-linking agents can be used alone or in combination of two or more, and the blending amount thereof is usually 0.001 to 20 parts by weight, preferably 0.001 to 20 parts by weight, based on 100 parts by weight of the acrylic rubber sheet or acrylic rubber veil. Is 0.1 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.

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

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

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

These anti-aging agents can be used alone or in combination of two or more, and the blending amount thereof is 0.01 to 15 parts by weight with respect to 100 parts by weight of the acrylic rubber sheet or acrylic rubber veil. It is preferably 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 an acrylic rubber having a reactive group contained in 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 antiaging agent, and further. , If necessary, other additives commonly used in the art, such as cross-linking aids, cross-linking accelerators, cross-linking retardants, silane coupling agents, plasticizers, processing aids, rubbers, pigments, coloring. Agents, antistatic agents, foaming agents and the like 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>
Examples of the method for producing the rubber mixture of the present invention include a method of mixing the filler, the cross-linking agent and the other compounding agent which can be contained as needed with the acrylic rubber sheet or the acrylic rubber bale of the present invention. Any means conventionally used in the field of rubber processing, for example, an open roll, a Banbury mixer, various kneaders, and the like can be used. That is, using these mixers, the acrylic rubber sheet or acrylic rubber veil can be mixed by directly mixing the filler, the cross-linking agent, or the like, preferably by directly kneading.

In that case, the acrylic rubber sheet or the acrylic rubber bale may be used as it is or by dividing (cutting or the like) the obtained sheet or bale.

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

The Mooney viscosity (ML1 + 4,100 ° C.; compound Mooney) of the rubber mixture of the present invention thus obtained is 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 with a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, or the like, and is crosslinked by heating. It can be produced by carrying out a reaction and fixing the shape as a rubber crosslinked product. In this case, cross-linking may be performed after molding in advance, or cross-linking may be performed at the same time as molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 150 ° C. The cross-linking temperature is usually 100 to 250 ° C., preferably 130 to 220 ° C., more preferably 150 to 200 ° C., and the cross-linking time is usually 0.1 minutes to 10 hours, preferably 1 minute to 5 hours. As the heating method, a method used for cross-linking rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

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

The rubber crosslinked product of the present invention is a sealing material such as an O-ring, packing, diaphragm, oil seal, shaft seal, bearing sheath, mechanical seal, well head seal, seal for electric / electronic equipment, seal for air compression equipment, and the like. A unit cell equipped with a rocker cover gasket attached to the connecting portion between the cylinder block and the cylinder head, an oil pan gasket attached to the connecting portion between the oil pan and the cylinder head or the transmission case, a positive electrode, an electrolyte plate and a negative electrode. Various gaskets such as gaskets for fuel cell separators and gaskets for top covers of hard disk drives mounted between a pair of sandwiched housings; cushioning material, vibration isolator; wire coating material; industrial belts; tubes and hoses; sheets It is preferably used as;

The rubber cross-linked product of the present invention is also used as an extruded molded product and a molded cross-linked product used in automobile applications, for example, fuel oil for fuel tanks such as fuel hoses, filler neck hoses, bent hoses, paper hoses, and oil hoses. 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 and acrylic rubber veils>
Next, an apparatus configuration used for manufacturing the acrylic rubber sheet and the acrylic rubber veil according to the 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 appropriately stirring with a stirrer, and emulsion polymerization is carried out in the presence of a polymerization catalyst to obtain an emulsion polymerization solution. Can be obtained. The liquid antiaging agent can be added to the emulsion polymerization solution as it is in the emulsion polymerization reactor. 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 agitating coagulation solution. That is, a water-containing crumb is generated by filling the stirring tank 30 of the coagulation device 3 with a coagulation liquid and adding and contacting the emulsion polymerization liquid with the coagulation liquid to coagulate the emulsion polymerization liquid.

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

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

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

The cleaning device 4 shown in FIG. 1 is configured to perform the processing related to the cleaning step described above. As schematically shown in FIG. 1, the cleaning device 4 includes, for example, a cleaning tank 40, a heating unit 41 that heats the inside of the cleaning tank 40, and a temperature control unit (not shown) that controls the temperature inside the cleaning tank 40. Have. In the cleaning device 4, the amount of ash in the finally obtained acrylic rubber 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. A hot air dryer, a vacuum dryer, an expander dryer, a kneader type dryer, or the like may be used as the dryer.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The die 59 is a mold arranged at the downstream end of the barrel unit 51, and has a discharge port having a predetermined nozzle shape. The acrylic rubber dried by the drying barrel portion 54 is extruded into a shape corresponding to a predetermined nozzle shape by passing through the discharge port of the die 59. In 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 the rotation of a pair of screws in the barrel unit 51. The hydrous crumb sent to the dry barrel portion 54 is plasticized and mixed to form a melt, which generates heat and is carried to the downstream side while raising the temperature. Then, the water contained in the melt of the acrylic rubber is vaporized, and the water (steam) is discharged to the outside through vent pipes (not shown) connected to the vent ports 58a, 58b, 58c, and 58d, respectively.

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

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

The rotation speed (N) of the pair of screws in the barrel unit 51 may be appropriately selected according to various conditions, and is usually 10 to 1000 rpm, and the water content of the acrylic rubber sheet and the gel amount of the insoluble methyl ethyl ketone. Is preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120 to 300 rpm, from the viewpoint of being able to efficiently reduce.

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

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

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

Hereinafter, as an example of the cooling device 6, the transport type cooling device 60 for cooling the sheet-shaped dry rubber 10 formed into a sheet shape will be described with reference to FIG.

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

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

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

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

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

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

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

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

The bale device 7 shown in FIG. 1 is configured to extrude from a screw type extruder 5 and further process a dry rubber cooled by the cooling device 6 to produce a bale which is a block. 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 a single amount. It was the same as the amount used by the body.

[Reactive group content]
The content of the reactive group of the acrylic rubber was measured by the following method in the acrylic rubber sheet or the acrylic rubber veil.
(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.

[Content of anti-aging agent]
The content (%) of the antioxidant in the acrylic rubber sheet or acrylic rubber bale is determined by dissolving the acrylic rubber sheet or acrylic rubber veil in tetrahydrofuran and performing gel permeation chromatography (GPC) measurement. Calculated based on the calibration curve.

[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 acrylic rubber was measured using a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi High-Tech Science Co., Ltd.).

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

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

[Complex viscosity]
The complex viscosity η of the acrylic rubber 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.

[Storing stability evaluation]
For the storage stability of the rubber sample, the rubber mixture of the rubber sample was put into a constant temperature and humidity chamber of 45 ° C. × 80% RH for 7 days, and the rubber sample before and after the test was used as the rubber mixture in a rubber vulcanization tester (moving dialeometer MDR; Perform a cross-linking test at 180 ° C. for 10 minutes using (manufactured by Alpha Technology) to calculate the rate of change in cross-linking density, which is the difference (MH-ML) between the maximum torque (MH) and the minimum torque (ML), and compare them. Example 1 was evaluated using an index of 100 (the smaller the index, the better the storage stability).

[Evaluation of workability]
Regarding the processability of the rubber sample, the rubber sample was put into a Banbury mixer heated to 50 ° C. and 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 to integrate and 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).

[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
[Evaluation of normal physical properties]
The normal physical properties of the rubber sample were evaluated according to the following criteria by measuring the breaking strength, 100% tensile stress and breaking elongation of the crosslinked rubber sample of the rubber sample according to JIS K6251.
(1) The breaking strength was evaluated as ⊚ for 10 MPa or more and × for less than 10 MPa.
(2) For 100% tensile stress, 5 MPa or more was evaluated as ⊚, and less than 5 MPa was evaluated as x.
(3) The elongation at break was evaluated as ⊚ for 150% or more and x for less than 150%.

[Example 1]
As shown in Table 2-1 in a mixing container equipped with a homomixer, 46 parts of pure water, 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate, and mono-fumarate. 1.5 parts of n-butyl and 1.8 parts of octyloxydioxyethylene phosphate sodium salt as an emulsifier were charged and stirred to obtain a monomeric emulsion.

Next, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were put into a polymerization reaction tank equipped with a thermometer and a stirrer, and cooled to 12 ° C. under a nitrogen stream. Next, the balance of the monomer emulsion, 0.00033 parts of ferrous sulfate, 0.264 parts of sodium ascorbate, and 0.22 parts of potassium persulfate were continuously added dropwise to the polymerization reaction tank over 3 hours. .. After that, the reaction was continued while the temperature in the polymerization reaction 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 stop the polymerization reaction. Then, 1 part of octyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate (Irganox 1135; manufactured by BASF) was added to obtain an emulsion polymerization solution.

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

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

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%
Moisture content of the hydrous crumb after drying in the 5th drying barrel: 0.4%
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 extruded sheet-shaped dry rubber was cooled to 50 ° C. and then cut with a cutter to obtain an acrylic rubber sheet (A). Measure the reactive group content, ash content, ash component content, specific gravity, gel amount, glass transition temperature (Tg), water content, molecular weight, molecular weight distribution and complex viscosity of the obtained acrylic rubber sheet (A). The results are shown in Table 2-2.

Next, the acrylic rubber sheet (A) was laminated so as to have 20 parts (20 kg) before the temperature became 40 ° C. or lower to obtain an acrylic rubber veil (A). Reactive group content, ash content, ash component content, specific gravity, gel amount, glass transition temperature (Tg), pH, antiaging agent content, water content, molecular weight, molecular weight distribution of the obtained acrylic rubber veil (A) And the complex viscosity was measured.

Next, 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. The BIT at this time was measured to evaluate the processability of the acrylic rubber bale, and the results are shown in Table 2-2.

Then, the obtained mixture was transferred to a roll at 50 ° C., and the compounding agent B of "Formulation 1" shown in Table 1 was mixed and mixed to obtain a rubber mixture. A cross-linking test of the rubber mixture using the acrylic rubber sheet (A) was performed before and after the storage stability test, changes in the cross-linking density (MH-ML) were measured, and the results are shown in Table 2-2.

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, and the water resistance evaluation and the normal physical properties were evaluated, and the results are shown in Table 2-2.

[Example 2]
The monomer component was 4.5 parts of ethyl acrylate, 64.5 parts of n-butyl acrylate, 29.5 parts of methoxyethyl acrylate and 1.5 parts of mono-n-butyl fumarate, and the emulsifier was nonylphenyloxy. Acrylic rubber sheet (B) and acrylic rubber bale (B) were obtained in the same manner as in Example 1 except that the sodium salt was changed to hexaoxyethylene phosphate sodium salt, and each characteristic was evaluated. The results of the acrylic rubber sheet (B) are shown in Table 2-2.

[Example 3]
Change the monomer component to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono n-butyl fumarate, and change the emulsifier to tridecyloxyhexaoxyethylene phosphate sodium salt. Except for the above, the same procedure as in Example 1 was carried out to obtain an acrylic rubber sheet (C) and an acrylic rubber bale (C), and each characteristic (the compounding agent was changed to "formulation 2") was evaluated. The results of the acrylic rubber sheet (C) are shown in Table 2-2.

[Example 4]
The temperature of the first dehydration barrel of the screw type extruder is changed to 100 ° C. and the temperature of the second dehydration barrel is changed to 120 ° C. so that drainage is performed only by the first dehydration barrel, and the first dehydration barrel is used. Acrylic rubber sheet (D) and acrylic rubber bale (D) were obtained in the same manner as in Example 3 except that the water content of the water-containing crumb after drainage was changed to 30%, and each characteristic was evaluated. The results of the acrylic rubber sheet (D) are shown in Table 2-2.

[Example 5]
Acrylic rubber was carried out in the same manner as in Example 4 except that the monomer component was changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allylglycidyl ether. A sheet (E) and an acrylic rubber bale (E) were obtained, and each characteristic (the compounding agent was changed to "formulation 3") was evaluated. The results of the acrylic rubber sheet (E) are shown in Table 2-2.

[Example 6]
Example 4 except that the monomer component is changed to 42.5 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 (F) and an acrylic rubber bale (F), and each characteristic (the compounding agent was changed to "formulation 4") was evaluated. The results of the acrylic rubber sheet (F) are shown in Table 2-2.

[Comparative Example 1]
In a mixing container equipped with a homomixer, 46 parts of pure water, 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile, 1.3 parts of vinyl chloroacetate As an emulsifier, 0.709 parts of sodium lauryl sulfate and 1.82 parts of polyoxyethylene dodecyl ether (molecular weight 1500) were charged and stirred to obtain a monomer emulsion.

Next, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were put into a polymerization reaction tank equipped with a thermometer and a stirrer, and cooled to 12 ° C. under a nitrogen stream. Next, the balance of the monomer emulsion, 0.00033 parts of ferrous sulfate, 0.264 parts of sodium ascorbate, and 0.22 parts of potassium persulfate were continuously added dropwise to the polymerization reaction tank over 3 hours. .. After that, the reaction was continued while the temperature in the polymerization reaction was maintained at 23 ° C., it was confirmed that the polymerization conversion rate reached approximately 100%, and hydroquinone as a polymerization terminator was added to stop the polymerization reaction. Then, 1 part of stearyl 3- (3,5-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076; manufactured by BASF) was added in a 50% by weight aqueous dispersion (0.1% by weight sodium lauryl sulfate dispersion). An emulsion polymerization solution added as a solution) was obtained.

Next, after heating the emulsion polymer solution to which the antiaging agent was added to 80 ° C., a 0.7% sodium sulfate aqueous solution (coagulant solution) was continuously added to the emulsion polymerization solution (rotation speed 100 rpm, peripheral speed 0.5 m / s). The polymer was coagulated and filtered off to obtain a hydrous crumb. To 100 parts of the obtained hydrous crumb, 194 parts of industrial water was added, and after stirring at 25 ° C. for 5 minutes, the hydrous crumb for discharging water from the coagulation tank was washed four times, and then a sulfuric acid aqueous solution having a pH of 3 194. After adding parts and stirring at 25 ° C for 5 minutes, water was discharged from the coagulation tank to perform acid cleaning once, then 194 parts of pure water was added and pure water cleaning was performed once, and then 160 ° C. A crumb-shaped acrylic rubber (G) having a water content of 0.4% by weight was obtained by drying with a hot air dryer. Each characteristic of the obtained crumb-shaped acrylic rubber (G) was evaluated and shown in Table 2-2.

[Comparative Example 2]
The same procedure as in Comparative Example 1 was carried out except that the antioxidant added to the emulsion polymerization solution was changed to 4,4'-bis (α, α-dimethylbenzyl) diphenylamine (Nocrack CD; manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.). A crumb-shaped acrylic rubber (H) was obtained. Each characteristic of the obtained crumb-shaped acrylic rubber (H) was evaluated and shown in Table 2-2.

From Table 2-2, it is composed of acrylic rubber containing (meth) acrylic acid ester as a main component and having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and the gel amount is 50% by weight or less and is liquid. It can be seen that the acrylic rubber sheets (A) to (F) containing the anti-aging agent are excellent in storage stability and processability, as well as in normal physical properties including strength characteristics and water resistance (Examples 1 to 6). ..

Regarding storage stability, the anti-aging agent contents of the acrylic rubber sheets (A) to (F) are the same as those of the crumb-shaped acrylic rubber (G), so that the liquid anti-aging agents are the acrylic rubber sheets (A) to (F). It is considered that the storage stability was remarkably improved due to the uniform microdispersion within (comparison between Examples 1 to 6 and Comparative Example 1). Further, after the storage stability test, no change in color tone was observed in the acrylic rubber sheets (A) to (H) of the present invention, but the crumb-shaped acrylic rubbers (G) to (H) in the comparative example were yellowed. There was.

Regarding workability, in the present invention, the polymerization conversion rate of emulsion polymerization is increased in order to improve the strength characteristics, but as the polymerization conversion rate is increased, the amount of gel rapidly increases and the processability of acrylic rubber deteriorates. However, the gel that has rapidly increased disappears when it is dried and melt-kneaded in a screw-type extruder to a state where there is virtually no water content (water content less than 1%), and the processability, strength characteristics, and storage of the acrylic rubber sheet are preserved. It can be seen that the stability is highly balanced (comparison between Examples 1 to 6 and Comparative Example 1).

Regarding water resistance, it can be seen from Table 2-2 that the acrylic rubber sheets (A) to (F) of the present invention are overwhelmingly superior to the crumb-shaped acrylic rubbers (G) to (H) (implementation). Comparison between Examples 1 to 6 and Comparative Examples 1 and 2). This is because the amount of ash in the acrylic rubber sheet was reduced by squeezing water from the water content crumb to a specific water content in the dehydration process, and a phosphate ester salt was used as an emulsifier and a magnesium salt was used as a coagulant. The water resistance of the acrylic rubber sheets (A) to (F) is improved by the fact that the ash content remaining on the acrylic rubber sheet at that time has a high content of magnesium and phosphorus and has almost no effect on the water resistance when both are in a specific ratio. It can be seen that it is significantly improved and that the normal physical properties including strength characteristics, processability and storage stability are highly balanced (Examples 1 to 6).

From Table 2-2, it further contains the phenolic antioxidant represented by the general formula (1) of the present invention, and contains a reactive group amount, a specific gravity, a gel amount, a glass transition temperature (Tg), a pH, a water content, and a weight. Average molecular weight (Mw), ratio of z average molecular weight (Mz) to weight average molecular weight (Mw) (Mz / Mw), ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn), Acrylic rubber sheet in which the complex viscosity η (100 ° C) at 100 ° C, the complex viscosity η (60 ° C) at 60 ° C, and the ratio of the complex viscosity η (η100 ° C / η60 ° C) at 100 ° C and 60 ° C are in a specific range. It can be seen that (A) to (F) are excellent in storage stability and processability, and are also excellent in normal physical properties including strength characteristics and water resistance (Examples 1 to 6). The characteristic values of the manufactured acrylic rubber veils (A) to (F) were the same as the characteristic values of the corresponding acrylic rubber sheets (A) to (F).

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

According to the present invention, an emulsion polymerization step of emulsion-polymerizing 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, An anti-aging agent addition step of adding a liquid anti-aging agent to the obtained emulsion polymerization solution, a coagulation step of bringing the emulsion polymerization solution to which the liquid anti-aging agent was added into contact with the coagulating liquid to generate a hydrous crumb, and the generated hydrous crumb. Water content up to 1-40% by weight in the dehydration barrel using a dehydration barrel with a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder with a die at the tip. Provided is a method for producing an acrylic rubber sheet, which comprises a dehydration / drying / molding step of dewatering and then drying in a drying barrel to a water content of less than 1% by weight and extruding a sheet-shaped dried rubber from a die.

<Manufacturing method of acrylic rubber sheet>
The method for producing the acrylic rubber sheet of the present invention is not particularly limited, but for example, a monomer component containing (meth) acrylic acid ester as a main component is emulsified with water and an emulsifier in the presence of a polymerization catalyst. A step of emulsifying and polymerizing to obtain an emulsified polymer solution, a step of adding an anti-aging agent to add a liquid anti-aging agent to the obtained emulsified polymer solution, and a step of adding an anti-aging agent to the obtained emulsion polymer solution, and contacting the emulsion polymer solution to which a liquid anti-aging agent is added with a coagulating solution A solidification step of forming a hydrous crumb, a cleaning step of cleaning the produced hydrous crumb, and a screw-type extrusion having a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a die at the tip of the washed hydrous crumb. By including a dehydration / drying / molding step of dehydrating to a moisture content of 1 to 40% by weight in a dehydration barrel using a machine, drying to a moisture content of less than 1% by weight in a drying barrel, and extruding a sheet-shaped dry rubber from a die. It can be easily manufactured.

Reactive group content, monomer composition, weight average molecular weight (Mw), ratio of z average molecular weight (Mz) to weight average molecular weight (Mw) (Mz / Mw) of acrylic rubber constituting the acrylic rubber veil of the present invention. ) And the glass transition temperature (Tg) are the same as the characteristic values of the acrylic rubbers constituting the acrylic rubber sheet.

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

From Table 2-2, it further contains the phenolic antioxidant represented by the general formula (1) of the present invention, and contains a reactive group amount, a specific gravity, a gel amount, a glass transition temperature (Tg), a pH, a water content, and a weight. Average molecular weight (Mw), ratio of z average molecular weight (Mz) to weight average molecular weight (Mw) (Mz / Mw ), complex viscosity η (100 ° C) at 100 ° C, complex viscosity η (60 ° C) at 60 ° C ) And the acrylic rubber sheets (A) to (F) in which the ratio of the complex viscosity ratios (η100 ° C./η60 ° C.) at 100 ° C. and 60 ° C. are in a specific range are excellent in storage stability and workability, and include strength characteristics. It can be seen that it is also excellent in normal physical properties and water resistance (Examples 1 to 6). The characteristic values of the manufactured acrylic rubber veils (A) to (F) were the same as the characteristic values of the corresponding acrylic rubber sheets (A) to (F).

Claims (19)

It is composed of acrylic rubber containing (meth) acrylic acid ester as a main component and having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and the gel amount of the insoluble methyl ethyl ketone is 50% by weight or less and liquid aging. Acrylic rubber sheet containing an inhibitor. The acrylic rubber sheet according to claim 1, wherein the content of the liquid anti-aging agent is in the range of 0.001 to 15% by weight. The acrylic rubber sheet according to claim 1 or 2, wherein the liquid anti-aging agent has a hindered structure. The acrylic rubber sheet according to any one of claims 1 to 3, wherein the liquid anti-aging agent is a phenol-based anti-aging agent. The liquid anti-aging agent is the general formula (1).
(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms), which is any of claims 1 to 4 which is a hindered phenolic antiaging agent. Acrylic rubber sheet described in. The acrylic rubber sheet according to any one of claims 1 to 5, wherein the ratio (Mz / Mw) of the z average molecular weight (Mz) to the weight average molecular weight (Mw) is 1.3 or more. The acrylic rubber sheet according to any one of claims 1 to 6, wherein the weight average molecular weight (Mw) is 1,000,000 or more. The acrylic rubber sheet according to any one of claims 1 to 7, wherein the pH is 6 or less. The acrylic rubber sheet according to any one of claims 1 to 8, which has a specific gravity of 0.7 or more. The acrylic rubber sheet according to any one of claims 1 to 9, wherein the amount of ash is 0.5% by weight or less. An emulsion polymerization step of emulsifying a metric 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.
An anti-aging agent addition step of adding a liquid anti-aging agent to the obtained emulsion polymerization solution,
A coagulation step in which an emulsion polymerization solution to which a liquid antiaging agent is added is brought into contact with a coagulation solution to form a hydrous crumb,
A cleaning process to clean the generated hydrous crumbs,
The washed hydrous crumb is dehydrated to a water content of 1 to 40% by weight in a dehydration barrel using a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw type extruder having a die at the tip, and then contained in the drying barrel. A method for producing an acrylic rubber sheet, which includes a dehydration / drying / molding step of drying a sheet-shaped dry rubber from a die by drying it to less than 1% by weight of water content. The method for producing an acrylic rubber sheet according to claim 11, wherein the polymerization conversion rate of emulsion polymerization is 90% by weight or more. An acrylic rubber veil obtained by laminating the acrylic rubber sheets according to any one of claims 1 to 10. A method for producing an acrylic rubber veil in which the acrylic rubber sheet according to any one of claims 1 to 10 is laminated. The method for producing an acrylic rubber veil according to claim 14, wherein the lamination temperature of the acrylic rubber sheet is 30 ° C. or higher. A rubber mixture obtained by mixing a reinforcing agent and a cross-linking agent with the acrylic rubber sheet according to any one of claims 1 to 10 or the acrylic rubber veil according to claim 13. A method for producing a rubber mixture, which comprises mixing a reinforcing agent and a cross-linking agent with the acrylic rubber sheet according to any one of claims 1 to 10 or the acrylic rubber veil according to claim 13 with a mixer. A method for producing an acrylic rubber sheet according to any one of claims 1 to 10 or a rubber mixture in which a cross-linking agent is mixed after mixing the acrylic rubber veil according to claim 13 with a reinforcing agent. A rubber crosslinked product obtained by cross-linking the rubber mixture according to claim 16.