JP7284110B2 - Acrylic rubber veil with excellent storage stability and water resistance - Google Patents

Description

TECHNICAL FIELD The present invention relates to an acrylic rubber veil, a method for producing the same, a rubber mixture, and a crosslinked rubber product. More specifically, the present invention relates to an acrylic rubber veil having excellent storage stability and water resistance, a method for producing the same, and a rubber obtained by mixing the acrylic rubber veil. It relates to a mixture and a cross-linked rubber obtained by cross-linking it.

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

Such acrylic rubber is usually produced by emulsion polymerization of the monomer components constituting the acrylic rubber, contacting the resulting emulsion polymerization liquid with a coagulant, drying the resulting water-containing crumbs, and baling them into products. be.

For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-328239) discloses a step of obtaining a crumb slurry containing a crumb-like rubber polymer by bringing a polymer latex into contact with a coagulating liquid, and A process of crushing the crumb-like rubber polymer contained in the crumb slurry in a mixer with a stirring and crushing function, and dehydration to obtain the crumb-like rubber polymer by removing water from the crumb slurry in which the crumb-like rubber polymer is crushed. and a step of heating and drying the crumb-like rubber polymer from which moisture has been removed, wherein the dried crumbs are introduced into a baler in the form of flakes and compressed into bales. It is described that it will be converted. Further, it is described that the maximum width of the crumb is preferably adjusted to about 3 to 20 mm when crushing with a mixer equipped with stirring and crushing functions. Examples of the rubber polymer used here include unsaturated nitrile-conjugated diene copolymer latex obtained by emulsion polymerization, ethyl acrylate/n-butyl acrylate copolymer, and ethyl acrylate/n-butyl acrylate copolymer. It has been shown to be applicable to copolymers composed only of acrylates, such as n-butyl acrylate/2-methoxyethyl acrylate copolymers. However, the acrylic rubber composed only of acrylate has a problem of poor cross-linked rubber properties such as heat resistance and compression set resistance.

As an acrylic rubber having a reactive group that is excellent in heat resistance and compression set resistance, for example, Patent Document 2 (International Publication No. 2018/116828) describes ethyl acrylate, n-butyl acrylate and fumaric acid. An acrylic rubber latex obtained by emulsifying a monomer component consisting of mono-n-butyl with sodium lauryl sulfate and polyethylene glycol monostearate as emulsifiers and water, and emulsion-polymerizing in the presence of a polymerization initiator until the polymerization conversion reaches 95%. is added to an aqueous solution of magnesium sulfate and a polymer flocculant, dimethylamine-ammonia-epichlorohydrin polycondensate, and stirred at 85 ° C. to form a crumb slurry. A method is disclosed in which, after washing with water, the entire amount is passed through a wire mesh of 100 mesh to capture only the solid content and to recover the crumb-like acrylic rubber. According to this method, the obtained crumbs in a moist state are dehydrated by centrifugation or the like, dried at 50 to 120 ° C. by a band dryer or the like, introduced into a baler and compressed into bales. there is However, in such a method, a large number of semi-solidified water-containing crumbs are generated in the coagulation reaction, and a large amount of them adhere to the coagulation tank. Even if it is baled with a baler, it has a problem of poor water resistance and storage stability.

JP 2006-328239 A International Publication No. 2018/116828 Pamphlet

The present invention has been made in view of such circumstances, and provides an acrylic rubber veil having excellent storage stability and water resistance, a method for producing the same, a rubber mixture comprising the acrylic rubber veil, and a rubber crosslinked product thereof. With the goal.

As a result of intensive research in view of the above problems, the present inventors have found that an acrylic rubber veil having a reactive group and having a specific molecular weight, ash content, specific component content in ash, and specific gravity has excellent storage stability and water resistance. I found it to be excellent.

The present inventors also emulsified a monomer component containing a reactive group-containing monomer, washed the water-containing crumbs produced by the coagulation reaction, and then dried them to a specific water content using a specific screw extruder. It was found that by extruding dry rubber and baling the extruded dry rubber, an acrylic rubber veil with excellent storage stability and water resistance can be produced.

The present inventors further improved the strength characteristics and storage stability by making the dry rubber extruded by the screw extruder into a sheet-shaped dry rubber, and laminating the extruded sheet-shaped dry rubber to form a bale. We have found that an excellent acrylic rubber veil can be produced.

The present inventors have also found that the water resistance and storage stability are remarkably improved by providing a dehydration step for squeezing water out of the water-containing crumbs washed in the washing step before the drying step.
The present inventors have completed the present invention based on these findings.

Thus, according to the present invention, an acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, an ash content of 0.8% by weight or less, and an amount of phosphorus in the ash is 10% by weight or more and has a specific gravity of 0.8 or more.

In the acrylic rubber veil of the present invention, it is preferable that the ash contains phosphorus and magnesium, and the total amount of phosphorus and magnesium in the ash is 30% by weight or more.

According to the present invention, a monomer component containing a (meth)acrylic acid ester and a reactive group-containing monomer is emulsified with water and a phosphoric acid-based emulsifier, and emulsion polymerization is performed in the presence of a polymerization catalyst. An emulsion polymerization step for obtaining a liquid, a coagulation step for producing wet crumbs by contacting the obtained emulsion polymerization liquid with a coagulating liquid, a washing step for washing the produced wet crumbs, and a screw type extrusion of the washed wet crumbs. A method for producing an acrylic rubber veil is provided, which includes a drying step of drying to a moisture content of less than 1% by weight using a machine and extruding the dried rubber, and a baling step of laminating and baling the extruded dried rubber.

Moreover, in the method for producing an acrylic rubber veil of the present invention, the coagulating liquid is preferably an aqueous magnesium salt solution.

Furthermore, in the method for producing an acrylic rubber veil of the present invention, it is preferable to further provide a dehydration step for squeezing water out of the washed water-containing crumbs.

Moreover, in the method for producing an acrylic rubber veil of the present invention, it is preferable that the dry rubber to be extruded is a sheet-shaped dry rubber, and that the sheet-shaped dry rubber is laminated in the baling.

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

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

INDUSTRIAL APPLICABILITY According to the present invention, an acrylic rubber veil excellent in storage stability and water resistance, a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber veil, and a rubber crosslinked product obtained by crosslinking the same are provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically an example of the acrylic-rubber manufacturing system used for manufacture of the acrylic-rubber veil which concerns on one Embodiment of this invention. FIG. 2 is a diagram showing the configuration of the screw-type extruder of FIG. 1; FIG. 2 is a diagram showing the configuration of a transport-type cooling device used as the cooling device in FIG. 1;

The acrylic rubber veil of the present invention is made of acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000. It is characterized by an amount ratio of 10% by weight or more and a specific gravity of 0.8 or more.

<Monomer component>
The acrylic rubber veil of the present invention is made of acrylic rubber having reactive groups.

The reactive group is not particularly limited and is appropriately selected according to the purpose of use, but preferably at least one functional group selected from the group consisting of carboxyl group, epoxy group and halogen group, more preferably carboxyl When it is a group, the cross-linking properties of the acrylic rubber veil can be improved to a high degree, which is preferable. As the reactive group, an ion-reactive group such as a carboxyl group or an epoxy group is preferable because it can particularly improve the water resistance. As the acrylic rubber having such a reactive group, a reactive group may be imparted to the acrylic rubber by a post-reaction, but the acrylic rubber is preferably obtained by copolymerizing a reactive group-containing monomer.

The acrylic rubber constituting the acrylic rubber sheet of the present invention is preferably one containing a (meth)acrylic acid ester, and is selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters. It preferably contains at least one (meth)acrylic acid ester.

Specific examples of preferred acrylic rubbers having reactive groups include at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters; Those composed of contained monomers and, if necessary, other copolymerizable monomers are mentioned.

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 having an alkyl group having 1 to 8 carbon atoms (meth)acrylic acid alkyl ester. ) alkyl acrylates, more preferably alkyl (meth)acrylates having an alkyl group of 2 to 6 carbon atoms.

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

The (meth)acrylic acid 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 having 2 to 8 alkoxyalkyl groups ) alkoxyalkyl acrylates, more preferably alkoxy(meth)acrylates having an alkoxyalkyl group having 2 to 6 carbon atoms.

Specific examples of (meth)acrylate alkoxyalkyl esters include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, (meth)acryl ethoxymethyl acid, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate and the like. Among these, methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate are preferred, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferred.

At least one (meth)acrylic acid ester selected from the group consisting of these (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters is used alone or in combination of two or more types, and acrylic The proportion in the rubber is usually 50% by weight or more, preferably 70-99.9% 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 obtained acrylic rubber may have poor weather resistance, heat resistance, and oil resistance, which is undesirable.

The reactive group-containing monomer is not particularly limited and is appropriately selected depending on the purpose of use, but a monomer having at least one functional group selected from the group consisting of carboxyl group, epoxy group and halogen group are preferred, monomers having an ion-reactive group such as a carboxyl group or an epoxy group are more preferred, and monomers having a carboxyl group are particularly preferred.

Although the monomer having a carboxyl group is not particularly limited, an ethylenically unsaturated carboxylic acid can be preferably used. Examples of ethylenically unsaturated carboxylic acids include ethylenically unsaturated monocarboxylic acids, ethylenically unsaturated dicarboxylic acids, and ethylenically unsaturated dicarboxylic acid monoesters. Esters are preferable because they can further enhance the resistance to compression set when acrylic rubber is used as a rubber crosslinked product.

The ethylenically unsaturated monocarboxylic acid is not particularly limited, but is preferably an ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms, such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, Cinnamic acid and the like can be mentioned.

The ethylenically unsaturated dicarboxylic acid is not particularly limited, but is preferably an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms. Maleic acid and the like can be mentioned. Incidentally, the ethylenically unsaturated dicarboxylic acids also include those existing as anhydrides.

Although the ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, it 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. and an alkyl monoester having 2 to 8 carbon atoms with an ethylenically unsaturated dicarboxylic acid, more preferably an alkyl monoester having 2 to 6 carbon atoms of butenedic acid having 4 carbon atoms.

Specific examples of ethylenically unsaturated dicarboxylic acid monoesters include monomethyl fumarate, monoethyl fumarate, mono-n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono-n-butyl maleate, monocyclopentyl fumarate, and fumarate. butenedioic acid monoalkyl esters such as monocyclohexyl acid, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate; itaconic acid such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate, monocyclohexyl itaconate and monoalkyl esters; among these, mono-n-butyl fumarate and mono-n-butyl maleate are preferred, and mono-n-butyl fumarate is particularly preferred.

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

Examples of monomers having a halogen group include unsaturated alcohol esters of halogen-containing saturated carboxylic acids, (meth)acrylic acid haloalkyl esters, (meth)acrylic acid haloacyloxyalkyl esters, (meth)acrylic acid (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.

Examples of unsaturated alcohol esters of halogen-containing saturated carboxylic acids include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate. (Meth)acrylate haloalkyl esters include, for example, chloromethyl (meth)acrylate, 1-chloroethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 1,2-dichloroethyl (meth)acrylate, Examples include 2-chloropropyl (meth)acrylate, 3-chloropropyl (meth)acrylate, and 2,3-dichloropropyl (meth)acrylate. (Meth)acrylic acid haloacyloxyalkyl esters include, for example, 2-(chloroacetoxy)ethyl (meth)acrylate, 2-(chloroacetoxy)propyl (meth)acrylate, 3-(chloroacetoxy)acrylate (meth)acrylate ) propyl, 3-(hydroxychloroacetoxy)propyl (meth)acrylate, and the like. Examples of (haloacetylcarbamoyloxy)alkyl esters of (meth)acrylic acid include 2-(chloroacetylcarbamoyloxy)ethyl (meth)acrylate and 3-(chloroacetylcarbamoyloxy)propyl (meth)acrylate. be done. Halogen-containing unsaturated ethers include, for example, chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, 3-chloropropyl allyl ether and the like. Halogen-containing unsaturated ketones include, for example, 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, 2-chloroethyl allyl ketone, and the like. Examples of halomethyl group-containing aromatic vinyl compounds include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, p-chloromethyl-α-methylstyrene and the like. Halogen-containing unsaturated amides include, for example, N-chloromethyl(meth)acrylamide. Haloacetyl group-containing unsaturated monomers include, for example, 3-(hydroxychloroacetoxy)propyl allyl ether, p-vinylbenzyl chloroacetate and the like.

These reactive group-containing monomers may be used alone or in combination of two or more. 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.

Other monomers used as necessary are not particularly limited as long as they are copolymerizable with the above monomers. Examples include aromatic vinyls, ethylenically unsaturated nitriles, acrylamide monomers, and others. and olefinic monomers. Examples of aromatic vinyl include styrene, α-methylstyrene, divinylbenzene and the like. Examples of ethylenically unsaturated nitriles include acrylonitrile and methacrylonitrile. Examples of acrylamide-based monomers include acrylamide and methacrylamide. Other olefinic monomers include, for example, ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, butyl vinyl ether and the like.

These other monomers may be used either alone or in combination of two or more. -15 parts by weight, most preferably 0-10 parts by weight.

<Acrylic rubber>
The acrylic rubber constituting the acrylic rubber veil of the present invention is characterized by having a reactive group.

The content of the reactive group may be appropriately selected depending on the purpose of use. It is preferably in the range of 0.05 to 1% by weight, particularly preferably 0.1 to 0.5% by weight. The characteristics are highly balanced and suitable.

Specific examples of the acrylic rubber constituting the acrylic rubber veil of the present invention include at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters, Reactive group-containing monomers and, if necessary, other copolymerizable monomers. At least one (meth)acrylic acid ester-derived linking unit selected from the group consisting of usually 50% by weight or more, preferably 70 to 99.9% by weight, more preferably 80 to 99.5% by weight, especially It is preferably in the range of 87 to 99% by weight, and the binding unit derived from the reactive group-containing monomer is usually 0.01 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.5% by weight. to 5% by weight, particularly preferably 1 to 3% by weight, and the binding unit derived from other monomers is usually 0 to 30% by weight, preferably 0 to 20% by weight, more preferably 0 to 15% by weight. % by weight, particularly preferably in the range from 0 to 10% by weight. By setting the linking units derived from these monomers in the acrylic rubber within this range, the object of the present invention can be achieved to a high degree, and when the acrylic rubber veil is crosslinked, the water resistance and compression set resistance can be significantly improved. Improved and preferred.

The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber veil of the present invention is 100,000 to 5,000,000, preferably 1,100,000 to 3, as an absolute molecular weight measured by GPC-MALS. , 500,000, more preferably in the range of 1,200,000 to 2,500,000. is.

The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber veil of the present invention is not particularly limited, but is measured by GPC-MALS. When the absolute molecular weight distribution is usually 1.3 or more, preferably 1.4 to 5, more preferably 1.5 to 2, the acrylic rubber veil is highly balanced in processability and strength properties and preserved. It is suitable for mitigating changes in physical properties over time.

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

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

<Acrylic rubber veil>
The acrylic rubber veil of the present invention is characterized by being made of the above acrylic rubber and having specific ash content, ash component content and specific gravity.

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

The ash content of the acrylic rubber veil of the present invention is . Although not particularly limited, it is 0.8% by weight or less, preferably 0.5% by weight or less, more preferably 0.4% by weight, particularly preferably 0.3% by weight or less, and most preferably 0.2% by weight. When it is at most % by weight, the storage stability and water resistance are excellent and suitable.

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

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

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

The amount of phosphorus in the ash content of the acrylic rubber veil of the present invention is not particularly limited, but is usually 10% by weight or more, preferably 20 to 70% by weight, more preferably 30 to 65% by weight, in terms of the total ash content. % by weight, particularly preferably 40 to 60% by weight, is suitable for excellent water resistance and storage stability.

The total amount of magnesium and phosphorus in the ash content of the acrylic rubber veil 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, in terms of the total ash content. When it is at least 80% by weight, preferably at least 80% by weight, the storage stability and water resistance are highly excellent.

The ratio of magnesium to phosphorus ([Mg]/[P]) in the ash content of the acrylic rubber veil of the present invention is not particularly limited as a weight ratio, but is usually 0.4 to 2.5, preferably 0. .4 to 1.3, more preferably 0.4 to 1, particularly preferably 0.45 to 0.75, most preferably 0.45 to 0.75.

The specific gravity of the acrylic rubber veil of the present invention is not particularly limited, but is 0.8 or more, preferably 0.8 to 1.4, more preferably 0.9 to 1.3, and particularly preferably 0.8. A range of 95 to 1.25, most preferably 1.0 to 1.2 is preferred because the storage stability is highly excellent. When the specific gravity of the acrylic rubber veil is small, it indicates that the amount of air entrained in the acrylic rubber veil is large, which greatly affects the storage stability including oxidation deterioration.

The amount of gel in the acrylic rubber veil of the present invention is not particularly limited, but the insoluble content of methyl ethyl ketone is usually 50% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less, and particularly Preferably, the content is 10% by weight or less, and most preferably 5% by weight or less, because the workability is highly improved. The amount of methyl ethyl ketone-insoluble gel in the acrylic rubber veil of the present invention differs depending on the solvent used, and was not correlated particularly with the amount of THF (tetrahydrofuran)-insoluble gel.

Although the water content of the acrylic rubber veil of the present invention is not particularly limited, vulcanization properties are usually obtained when it is less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. It is suitable for its highly optimized properties such as heat resistance and water resistance.

The pH of the acrylic rubber veil 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. Storage stability is highly improved, which is preferable.

The complex viscosity ([η]60°C) of the acrylic rubber veil 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, are suitable for excellent workability, oil resistance and shape retention.

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

The ratio of the complex viscosity at 100°C ([η] 100°C) to the complex viscosity at 60°C ([η] 60°C) of the acrylic rubber veil of the present invention ([η] 100°C/[η] 60°C) is not particularly limited, but is usually 0.5 or more, preferably 0.5 to 0.98, more preferably 0.6 to 0.95, most preferably 0.75 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 veil of the present invention is not particularly limited, but is usually in the range of 10 to 150, preferably 20 to 100, more preferably 25 to 70. It is suitable because it has a highly balanced property and strength characteristics.

<Method for manufacturing acrylic rubber veil>
The above acrylic rubber veil is obtained by emulsifying a monomer component containing a (meth)acrylic acid ester and a reactive group-containing monomer with water and a phosphoric acid emulsifier in the presence of a polymerization catalyst to achieve a polymerization conversion rate of 90% by weight. An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization up to the above,
a coagulation step of contacting the obtained emulsion polymerization liquid and the coagulation liquid to generate water-containing crumbs;
a washing step for washing the produced hydrous crumbs;
A dewatering/drying/molding step of drying the washed wet crumbs using a screw type extruder to a moisture content of less than 1% by weight and extruding dry rubber;
a baling step of baling the extruded dry rubber;
It can be easily manufactured by a manufacturing method including

(Emulsion polymerization step)
In the emulsion polymerization step in the method for producing an acrylic rubber veil of the present invention, a monomer component containing a (meth)acrylic acid ester and a reactive group-containing monomer is emulsified with water and an emulsifier and polymerized in the presence of a polymerization catalyst. In this step, emulsion polymerization is performed until the conversion rate reaches 90% by weight or more to obtain an emulsion polymerization liquid.

The monomer components to be used are the same as those described for the monomer components, and the amount used is appropriately selected so as to achieve the monomer composition of the acrylic rubber constituting the acrylic rubber veil. Well, usually, the amount is equivalent to the monomer composition of the acrylic rubber constituting the acrylic rubber veil.

The phosphoric acid-based emulsifier to be used is not particularly limited as long as it is commonly used in emulsion polymerization reactions. Phosphate esters or salts thereof can be preferably used.

Examples of alkyloxypolyoxyalkylene phosphates or salts thereof include alkyloxypolyoxyethylene phosphates or salts thereof, alkyloxypolyoxypropylene phosphates or salts thereof. Oxyethylene phosphates or salts thereof are preferred, and alkyloxypolyoxyethylene phosphate salts are particularly preferred.

Examples of alkyloxypolyoxyethylene phosphates or salts thereof include octyloxydioxyethylene phosphates, octyloxytrioxyethylene phosphates, octyloxytetraoxyethylene phosphates, and decyloxytetraoxyethylene phosphates. ester, dodecyloxytetraoxyethylene phosphate, tridecyloxytetraoxyethylene phosphate, tetradecyloxytetraoxyethylene phosphate, hexadecyloxytetraoxyethylene phosphate, octadecyloxytetraoxyethylene phosphate, Octyloxypentoxyethylene phosphate, decyloxypentoxyethylene phosphate, dodecyloxypentoxyethylene phosphate, tridecyloxypentoxyethylene phosphate, tetradecyloxypentoxyethylene phosphate, hexadecyloxy Pentaoxyethylene Phosphate, Octadecyloxypentoxyethylene Phosphate, Octyloxyhexaoxyethylene Phosphate, Decyloxyhexaoxyethylene Phosphate, Dodecyloxyhexaoxyethylene Phosphate, Tridecyloxyhexaoxyethylene Phosphate acid ester, tetradecyloxyhexaoxyethylene phosphate, hexadecyloxyhexaoxyethylene phosphate, octadecyloxyhexaoxyethylene phosphate, octyloxyoctaoxyethylene phosphate, decyloxyoctaoxyethylene phosphate, dodecyloxyoctaoxyethylene phosphate, tridecyloxyoctaoxyethylene phosphate, tetradecyloxyoctaoxyethylene phosphate, hexadecyloxyoctaoxyethylene phosphate, octadecyloxyoctaoxyethylene phosphate, and the like, and Metal salts thereof and the like are included, preferably metal salts thereof, more preferably alkali metal salts thereof, and most preferably sodium salts thereof.

Alkyloxypolyoxypropylene phosphates or salts thereof are not particularly limited, but examples include octyloxydioxypropylene phosphates, octyloxytrioxypropylene phosphates, octyloxytetraoxypropylene phosphates, Decyloxytetraoxypropylene phosphate, Dodecyloxytetraoxypropylene phosphate, Tridecyloxytetraoxypropylene phosphate, Tetradecyloxytetraoxypropylene phosphate, Hexadecyloxytetraoxypropylene phosphate, Octadecyloxy Tetraoxypropylene Phosphate, Octyloxypentoxypropylene Phosphate, Decyloxypentoxypropylene Phosphate, Dodecyloxypentoxypropylene Phosphate, Tridecyloxypentoxypropylene Phosphate, Tetradecyloxypentoxypropylene Phosphate Phosphate, hexadecyloxypentoxypropylene phosphate, octadecyloxypentoxypropylene phosphate, octyloxyhexaoxypropylene phosphate, decyloxyhexaoxypropylene phosphate, dodecyloxyhexaoxypropylene phosphate, tridecyloxyhexaoxypropylene phosphate, tetradecyloxyhexaoxypropylene phosphate, hexadecyloxyhexaoxypropylene phosphate, octadecyloxyhexaoxypropylene phosphate, octyloxyoctaoxypropylene phosphate, decyloxy Octaoxypropylene phosphate, dodecyloxyoctaoxypropylene phosphate, tridecyloxyoctaoxyethylene phosphate, tetradecyloxyoctaoxypropylene phosphate, hexadecyloxyoctaoxypropylene phosphate, octadecyloxyoctaoxy and metal salts thereof, preferably metal salts thereof, more preferably alkali metal salts thereof, most preferably sodium salts thereof.

Examples of alkylphenyloxypolyoxyalkylene phosphates or salts thereof include alkylphenyloxypolyoxyethylene phosphates or salts thereof, alkylphenyloxypolyoxypropylene phosphates or salts thereof. Alkylphenyloxypolyoxyethylene phosphate ester salts are preferred.

Examples of alkylphenyloxypolyoxyethylene phosphates or salts thereof include methyloxytetraoxyethylene phosphates, ethylphenyloxytetraoxyethylene phosphates, butylphenyloxytetraoxyethylene phosphates, hexylphenyloxy Tetraoxyethylene phosphate, nonylphenyloxytetraoxyethylene phosphate, dodecylphenyloxytetraoxyethylene phosphate, octadecyloxytetraoxyethylene phosphate, methylphenyloxypentoxyethylene phosphate, ethylphenyloxypenta Oxyethylene Phosphate, Butylphenyloxypentoxyethylene Phosphate, Hexylphenyloxypentoxyethylene Phosphate, Nonylphenyloxypentoxyethylene Phosphate, Dodecylphenyloxypentoxyethylene Phosphate, Methylphenyloxyhexa Oxyethylene phosphate, ethylphenyloxyhexaoxyethylene phosphate, butylphenyloxyhexaoxyethylene phosphate, hexylphenyloxyhexaoxyethylene phosphate, nonylphenyloxyhexaoxyethylene phosphate, dodecylphenyloxyhexa Oxyethylene Phosphate, Methylphenyloxyhexaoxyethylene Phosphate, Ethylphenyloxyoctaoxyethylene Phosphate, Butylphenyloxyoctaoxyethylene Phosphate, Hexylphenyloxyoctaoxyethylene Phosphate, Nonylphenyloxyocta Oxyethylene phosphate, dodecylphenyloxyoctaoxyethylene phosphate, and the like, and metal salts thereof, preferably metal salts thereof, more preferably alkali metal salts thereof, most preferably sodium salts thereof. be.

Alkylphenyloxypolyoxypropylene phosphates or salts thereof are not particularly limited, but examples include methylphenyloxytetraoxypropylene phosphates, ethylphenyloxytetraoxypropylene phosphates, butylphenyloxytetraoxypropylene phosphates, Phosphates, hexylphenyloxytetraoxypropylene phosphates, nonylphenyloxytetraoxypropylene phosphates, dodecylphenyloxytetraoxypropylene phosphates, methylphenyloxypentaoxypropylene phosphates, ethylphenyloxypentaoxypropylene phosphates Phosphate, butylphenyloxypentoxypropylene phosphate, hexylphenyloxypentoxypropylene phosphate, nonylphenyloxypentoxypropylene phosphate, dodecylphenyloxypentoxypropylene phosphate, methylphenyloxyhexaoxypropylene Phosphate, ethylphenyloxyhexaoxypropylene phosphate, butylphenyloxyhexaoxypropylene phosphate, hexylphenyloxyhexaoxypropylene phosphate, nonylphenyloxyhexaoxypropylene phosphate, dodecylphenyloxyhexaoxypropylene Phosphate Ester, Methylphenyloxyoctaoxypropylene Phosphate, Ethylphenyloxyoctaoxypropylene Phosphate, Butylphenyloxyoctaoxypropylene Phosphate, Hexylphenyloxyoctaoxyethylene Phosphate, Nonylphenyloxyoctaoxypropylene Phosphate Phosphates, dodecylphenyloxyoctaoxypropylene phosphates and the like, and metal salts thereof, preferably metal salts thereof, more preferably alkali metal salts thereof, most preferably sodium salts thereof.

The method for mixing the monomer component, water and emulsifier may be a conventional method, 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 generally 10 to 750 parts by weight, preferably 50 to 500 parts by weight, more preferably 100 to 400 parts by weight, per 100 parts by weight of the monomer component.

The polymerization catalyst to be used is not particularly limited as long as it is commonly used in emulsion polymerization. For example, a redox catalyst comprising a radical generator and a reducing agent can be used.

Examples of radical generators include peroxides and azo compounds, preferably peroxides. Inorganic peroxides and organic peroxides are used as peroxides.

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

The organic peroxide is not particularly limited as long as it is a known one used in emulsion polymerization. For example, 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane , 1-di-(t-hexylperoxy)cyclohexane, 1,1-di-(t-butylperoxy)cyclohexane, 4,4-di-(t-butylperoxy)n-butyl valerate, 2, 2-di-(t-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, para-menthane hydroperoxide, benzoyl peroxide, 1,1,3,3-tetraethyl Butyl hydroperoxide, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, diisobutyryl peroxide , di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 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-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, t-hexyl peroxypivalate, t-butyl peroxyneodecanate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 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-hexylperoxyisopropyl monocarbonate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, 2,5-dimethyl-2,5 -di(benzoylperoxy)hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, etc. Among these, diisopropylbenzene hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide, benzoyl peroxide and the like are preferred.

Examples of azo compounds include azobisisobutyronitrile, 4,4′-azobis(4-cyanovaleric acid), 2,2′-azobis[2-(2-imidazolin-2-yl)propane, 2,2 '-azobis (propane-2-carbamidine), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropanamide], 2,2'-azobis {2-[1-(2- hydroxyethyl)-2-imidazolin-2-yl]propane}, 2,2′-azobis(1-imino-1-pyrrolidino-2-methylpropane) and 2,2′-azobis{2-methyl-N-[ 1,1-bis(hydroxymethyl)-2-hydroxyethyl]propanamide} and the like.

These radical generators can be used either alone or in combination of two or more. It ranges from 0.0005 to 1 part by weight, more preferably from 0.001 to 0.5 part by weight.

As the reducing agent, any reducing agent that can be used as a redox catalyst for emulsion polymerization can be used without particular limitation. In the present invention, it is particularly preferable to use at least two kinds of reducing agents. As the at least two 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 a reduced state is not particularly limited, but examples thereof include ferrous sulfate, ferrous sodium hexamethylenediaminetetraacetate, and cuprous naphthenate, among which ferrous sulfate is preferred. These metal ion compounds in a reduced state can be used alone or in combination of two or more. 01 parts by weight, preferably 0.00001 to 0.001 parts by weight, more preferably 0.00005 to 0.0005 parts by weight.

The reducing agent other than the metal ion compounds in their reduced state is not particularly limited, but for example, ascorbic acid or salts thereof such as ascorbic acid, sodium ascorbate, potassium ascorbate; erythorbic acid, sodium erythorbate, erythorbin erythorbic acid or its salts such as potassium acid; sulfinates such as sodium hydroxymethanesulfinate; sulfites of sodium sulfite, potassium sulfite, sodium hydrogen sulfite, aldehyde sodium bisulfite, potassium hydrogen sulfite; sodium pyrosulfite, potassium pyrosulfite Pyrosulfites such as , sodium pyrosulfite and potassium pyrosulfite; Thiosulfates such as sodium thiosulfate and potassium thiosulfate; phosphorous acid or salts thereof; pyrophosphorous acids or salts thereof such as pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, sodium hydrogen pyrophosphite, potassium hydrogen pyrophosphite; and sodium formaldehyde sulfoxylate. Among these, ascorbic acid or its salts, sodium formaldehyde sulfoxylate and the like are preferred, and ascorbic acid or its salts are particularly preferred.

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

A preferred combination of a metal ion compound in a reduced state and another reducing agent is ferrous sulfate and ascorbic acid or its salt and/or sodium formaldehyde sulfoxylate, more preferably ferrous sulfate and ascorbate. and/or sodium formaldehyde sulfoxylate, most preferably a combination of ferrous sulfate and ascorbate. 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 to 0.001 parts by weight, per 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 per 100 parts by weight of the monomer component, The range is preferably 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 the same as that used in the emulsification of the monomer components. ~500 parts by weight, more preferably 80 to 400 parts by weight, most preferably 100 to 300 parts by weight.

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

The polymerization conversion rate of the emulsion polymerization reaction is not particularly limited, but when it is usually 80% by weight or more, preferably 90% by weight or more, and more preferably 95% by weight or more, the acrylic rubber veil produced has excellent strength characteristics. Moreover, it is suitable because it has no monomer odor. A polymerization terminator may be used for terminating the polymerization.

(coagulation process)
The coagulation step in the method for producing an acrylic rubber sheet of the present invention is characterized by adding the emulsion polymerization liquid obtained above to a coagulant liquid (aqueous solution containing a coagulant) that is being stirred to generate water-containing crumbs.

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

The coagulant used is not particularly limited, but metal salts are usually used. Examples of metal salts include alkali metal salts, periodic table group 2 metal salts, and other metal salts, preferably alkali metal salts and periodic table group 2 metal salts, more preferably periodic table group 2 metal salts. Salts, particularly preferably magnesium salts.

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

Examples of Group 2 metal salts of the periodic table include magnesium chloride, calcium chloride, magnesium nitrate, calcium nitrate, magnesium sulfate, and calcium sulfate, preferably calcium chloride and magnesium sulfate, and more preferably magnesium sulfate.

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.

These coagulants may be used alone or in combination of two or more. The amount used is usually 0.01 to 100 parts by weight, preferably 0.01 to 100 parts by weight, per 100 parts by weight of the monomer component. It ranges from 1 to 50 parts by weight, more preferably from 1 to 30 parts by weight. When the coagulant is within this range, the coagulation of the acrylic rubber is sufficient, and the compression set resistance and water resistance of the crosslinked acrylic rubber veil can be highly improved, which is preferable.

When the coagulant concentration of the coagulating liquid is usually 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% by weight. It is preferable that the grain size of the produced hydrous crumbs can be uniformly concentrated in a specific region.

Although the temperature of the coagulating liquid is not particularly limited, it is usually 40° C. or higher, preferably 40 to 90° C., and more preferably 50 to 80° C., because uniform water-containing crumbs are produced.

The stirring speed (rotational speed) of the coagulated liquid being stirred, that is, the rotating speed of the stirring blades of the stirrer, is not particularly limited, but is usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm. , particularly preferably in the range of 400-800 rpm. It is preferable that the number of revolutions is a number of revolutions at which the crumbs are stirred vigorously to some extent because the grain size of the water-containing crumbs to be generated can be made small and uniform. can be suppressed from being produced, and by making it equal to or less than the above upper limit, the control of the coagulation reaction can be made easier.

The peripheral speed of the coagulated liquid being stirred, that is, the speed of the outer periphery of the stirring blade of the stirring device, is not particularly limited, but vigorous stirring to a certain extent reduces the grain size of the water-containing crumbs generated and It is suitable for uniformity and 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, most preferably 2.5 m/s or more. On the other hand, the upper limit of the peripheral speed is not particularly limited, but it is usually 50 m / s or less, preferably 30 m / s or less, more preferably 25 m / s or less, most preferably 20 m / s or less. This is preferable because the reaction can be easily controlled.

By setting the above conditions of the coagulation reaction in the coagulation process (contact method, solid content concentration of the emulsion polymerization liquid, concentration and temperature of the coagulation liquid, rotation speed and peripheral speed during stirring of the coagulation liquid, etc.) to a specific range, generation The shape and crumb diameter of the water-containing crumbs are uniform and bundled, and the removal of emulsifiers and coagulants during washing and dehydration is remarkably improved.

(Washing process)
The washing step in the method for producing an acrylic rubber veil of the present invention is a step of washing the produced water-containing crumbs with water.

The washing method is not particularly limited and may be carried out according to a conventional method. For example, the produced water-containing crumbs may be mixed with a large amount of water.

The amount of water to be used is not particularly limited. A range of preferably 100 to 10,000 parts by weight, particularly preferably 150 to 5,000 parts by weight is suitable because the ash content in the acrylic rubber can be effectively reduced.

The temperature of water for washing 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., most preferably 60 to 80° C. ° C. is preferable because the cleaning efficiency can be remarkably increased.

By setting the temperature of the washing water to be equal to or higher than the above lower limit, the emulsifier and the coagulant are separated from the water-containing crumbs, thereby further improving the washing efficiency.

Although the washing time is not particularly limited, it is usually in the range of 1 to 120 minutes, preferably 2 to 60 minutes, more preferably 3 to 30 minutes.

The number of washings is not particularly limited, and is usually 1 to 10 times, preferably multiple times, and more preferably 2 to 3 times. From the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber, it is desirable to wash with water more often, but the shape and diameter of the water-containing crumbs should be specified and/or By setting the washing temperature within the above range, the number of times of washing can be significantly reduced.

(Dehydration process)
In the method for producing an acrylic rubber veil of the present invention, a dehydration step for squeezing water out of the water-containing crumbs after washing is provided before the drying step to remove the ash content composed of emulsifiers and coagulants that could not be removed in the washing step. It is preferable that the water resistance of the acrylic rubber veil can be significantly improved by reducing the amount of water, and the storage stability and workability can be improved.

There are no particular limitations on the dehydrator, and conventional methods may be used. Examples thereof include a centrifugal separator, a squeezer, and a screw-type extruder. can be lowered to . Sticky acrylic rubber can only be dehydrated to about 45 to 55% by weight in a centrifugal separator due to the acrylic rubber adhering between the walls and slits. A mechanism that keeps moving is preferable.

The water content of the water-containing crumbs after dehydration is not particularly limited, but is usually 1 to 50% by weight, preferably 1 to 40% by weight, more preferably 10 to 40% by weight, more preferably 15 to 35% by weight. Range. By setting the water content after dehydration to the above lower limit or more, the dehydration time can be shortened and deterioration of the acrylic rubber can be suppressed, and by setting it to the above upper limit or less, the ash content can be sufficiently reduced.

(Drying process)
The drying step in the method for producing an acrylic rubber veil of the present invention is a step of drying the water-containing crumbs after washing, preferably after dehydration, using a screw extruder to extrude dry rubber having a water content of less than 1% by weight. .

The temperature of the water-containing crumbs introduced into the screw extruder is not particularly limited, but is usually 40°C or higher, preferably 40 to 100°C, more preferably 50 to 90°C, particularly preferably 55 to 85°C, and most preferably. When the temperature is in the range of 60 to 80°C, the water-containing crumb, which has a specific heat of 1.5 to 2.5 KJ/kg K and is difficult to raise the temperature like the acrylic rubber of the present invention, is reliably dried in a screw extruder. It is possible and suitable. In particular, in the present invention, the water-containing crumbs are dried in a screw extruder to a state that does not substantially contain water (water content after dehydration described below) and melt-kneaded during production, particularly emulsion polymerization. It is important because it eliminates the rapidly increasing gel content when the conversion rate is increased.

The drying temperature of the screw-type extruder may be selected as appropriate, but when it is usually in the range of 100 to 250° C., preferably 110 to 200° C., more preferably 120 to 180° C., discoloration or deterioration of the acrylic rubber occurs. It is suitable because it can dry efficiently without drying and can reduce the amount of gel in the acrylic rubber veil.
The shape of the dried rubber is not particularly limited, and examples include crumb, powder, rod, and sheet. ) It is suitable because it can be made into an acrylic rubber veil with excellent storage stability.

The moisture content of the dry rubber is less than 1 wt%, preferably 0.8 wt% or less, more preferably 0.6 wt% or less.

(Bale process)
The baling step in the method for producing an acrylic rubber veil of the present invention is a step of baling the obtained dry rubber having a water content of less than 1% by weight.

The dry rubber can be bale-formed according to a conventional method. For example, the dry rubber can be put into a baler and compressed. The compression pressure is appropriately selected depending on the purpose of use, and is usually in the range of 0.1 to 15 MPa, preferably 0.5 to 10 MPa, more preferably 1 to 5 MPa. The compression time is not particularly limited, but is usually in the range of 1 to 60 seconds, preferably 5 to 30 seconds, more preferably 10 to 20 seconds.

In the present invention, it is also possible to prepare sheets of dry rubber and laminate them to form bales. The lamination of sheets to form a bale is suitable because it is easy to manufacture, and a bale with few air bubbles (high specific gravity) can be obtained, and it is excellent in storage stability, workability and handleability.

(Dehydration/drying process and baling process by screw type extruder)
In the present invention, the dehydration step and the drying step are preferably performed using a screw-type extruder equipped with a dehydration barrel having a dehydration slit, a drying barrel for drying under reduced pressure, and a die at the tip. , and preferably followed by a baling step, and the embodiment thereof is shown below.

Draining process In the method for producing an acrylic rubber veil of the present invention, before shifting from the washing process to the dewatering/drying process, it is preferable to provide a draining process for separating free water from the water-containing crumbs after washing with a drainer for dehydration and drying 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 drainer mesh opening is not particularly limited, but when it is usually in the range of 0.01 to 5 mm, preferably 0.1 to 1 mm, more preferably 0.2 to 0.6 mm, the loss of wet crumbs is small. Moreover, it is suitable for efficient draining.

The water content of the water-containing crumbs after draining, that is, the water content of the water-containing crumbs put into the dewatering/drying/forming process is not particularly limited, but is usually 50 to 80% by weight, preferably 50 to 70% by weight. , more preferably in the range of 50 to 60% by weight.

The temperature of the water-containing crumbs after draining, that is, the temperature of the water-containing crumbs introduced into the dewatering/drying/forming process is not particularly limited, but is usually 40°C or higher, preferably 40 to 95°C, more preferably 50°C. ~90°C, particularly preferably 55-85°C, most preferably 60-80°C

Dehydration and drying in the dehydration barrel section Dehydration of the wet crumb is performed in a dehydration barrel having a dehydration slit. The opening of the dewatering slit may be appropriately selected according to the conditions of use, but when it is usually in the range of 0.1 to 1 mm, preferably 0.2 to 0.6 mm, the loss of water-containing crumbs is small. Moreover, the water-containing crumbs can be efficiently dewatered, which is suitable.

The number of dewatering barrels in the screw-type extruder is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 6, in order to dehydrate the sticky acrylic rubber. It is suitable for efficient performance.

There are two ways to remove water from the water-containing crumb in the dewatering barrel: removal in liquid form (wastewater) and removal in vapor form (exhaust steam) through the dewatering slits. Exhaust steam is defined as dry and distinguished.

When a screw type extruder equipped with a plurality of dewatering barrels is used, it is preferable to combine drainage and exhaust steam to efficiently drain (dehydrate) the adhesive acrylic rubber and reduce the water content. A screw type extruder equipped with three or more dehydrating barrels may be selected between a drainage type dehydration barrel and a steam discharge type dehydration barrel as appropriate according to the purpose of use. If so, the number of drainage barrels should be increased. For example, if there are three dewatering barrels, the number of drainage barrels should be two, and if there are four dewatering barrels, the number of drainage barrels should be three.

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

The water content after dehydration of the water-containing crumbs 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, and particularly preferably 5 to 35% by weight. is preferably 10 to 35% by weight because productivity and distribution removal efficiency are highly balanced.

When the sticky acrylic rubber is dehydrated using a centrifugal separator, the acrylic rubber adheres to the dewatering slit and can hardly be dewatered (water content is up to about 45 to 55% by weight). The use of a screw-type extruder with a dewatering slit and forcibly squeezed by a screw made it possible to reduce the water content to this extent.

Dehydration of the water-containing crumb in the case of having a drainage type dehydration barrel and a discharge steam type dehydration barrel is performed so that the water content in the drainage type dehydration barrel is usually 5 to 45% by weight, preferably 10 to 40% by weight, more preferably 15 to 45% by weight. 35% by weight, and the water content in the exhaust steam type dehydration barrel is usually 1 to 30% by weight, preferably 3 to 20% by weight, more preferably 5 to 15% by weight.

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

Drying in the Drying Barrel Section The water-containing crumbs dehydrated and dried in the dehydrating barrel section are further dried in the drying barrel section under reduced pressure.

The degree of pressure reduction in the drying barrel may be selected as appropriate, but when it is usually 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa, the water-containing crumbs can be dried efficiently.

The set temperature of the drying barrel may be selected as appropriate, but when it is usually in the range of 100 to 250°C, preferably 110 to 200°C, more preferably 120 to 180°C, the acrylic rubber does not burn or deteriorate. It is suitable because it can dry efficiently and can reduce the amount of acrylic rubber gel.

The number of drying barrels in the screw type extruder is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 8. In the case of using a plurality of drying barrels, the degree of pressure reduction may be similar in all the drying barrels, or may be changed. When there are multiple drying barrels, the set temperature may be set to a similar temperature for all the drying barrels or may be changed. It is preferable to raise the temperature of method (1) because the drying efficiency can be increased.

The moisture content of the dry rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less.

Shape of acrylic rubber (die part)
The acrylic rubber dehydrated and dried in the screw portions of the dewatering barrel and the drying barrel is sent to a straightening 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.

Depending on the shape of the die nozzle, acrylic rubber can be extruded in various shapes such as granules, columns, rods, and sheets. It is suitable for obtaining a dry rubber having a small amount, a large specific gravity, and excellent storage stability.

The resin pressure in the die part is not particularly limited, but when it is usually in the range of 0.1 to 10 MPa, preferably 0.5 to 5 MPa, and more preferably 1 to 3 MPa, air entrainment is small and productivity is excellent. preferred.

Screw extruder and operating conditions The screw length (L) of the screw extruder to be used may be appropriately selected depending on the purpose of use, usually 3000 to 15000 mm, preferably 4000 to 10000 mm, more preferably 4500 ~8000 mm.

The screw diameter (D) of the screw-type extruder to be used may be appropriately selected depending on the purpose of use, and is usually in the range of 50-250 mm, preferably 100-200 mm, more preferably 120-160 mm.

The ratio (L/D) between the screw length (L) and the screw diameter (D) of the screw extruder used is not particularly limited, but is usually 10 to 100, preferably 20 to 80, more It is preferably in the range of 30 to 60, more preferably in the range of 40 to 50, because the moisture content can be reduced to less than 1% by weight without causing a reduction in the molecular weight of the dry rubber or scorching.

The number of rotations (N) of the screw 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, most preferably 120 A speed of up to 300 rpm is suitable because the water content and gel content of the acrylic rubber can be efficiently reduced.

The throughput (Q) of the screw 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, most preferably 500 ~800 kg/hr.

The ratio (Q/N) of the output (Q) and the rotation speed (N) of the screw 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.

The shape of the dried rubber extruded from the dry rubber screw type extruder is not particularly limited, and examples thereof include crumb, powder, rod, sheet, etc. Among these, sheet is particularly preferred.

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

The moisture content of the dry rubber extruded from the screw extruder is less than 1 wt%, preferably 0.8 wt% or less, more preferably 0.6 wt% or less.

Baling process The baling process after the dehydration and drying process by the screw type extruder is a process of baling the extruded dry rubber. The dry rubber can be bale-formed according to a conventional method. For example, the dry rubber can be put into a baler and compressed. The compression pressure of the baler may be appropriately selected depending on the purpose of use, but is usually in the range of 0.1-15 MPa, preferably 0.5-10 MPa, more preferably 1-5 MPa. The compression temperature is not particularly limited, but is usually in the range of 10-80°C, preferably 20-60°C, more preferably 30-60°C. The compression time may be appropriately selected depending on the purpose of use, and is usually in the range of 1 to 100 seconds, preferably 2 to 50 seconds, more preferably 5 to 25 seconds.

In the present invention, a sheet of dried rubber is extruded from a screw extruder in the dehydration and drying steps, cut as necessary, and laminated to form a bale. Forming a bale by laminating sheet-shaped dried rubber is suitable because it is easy to manufacture, and a bale with few air bubbles (high specific gravity) can be obtained, and the storage stability is excellent. The following shows a mode in which sheets of dry rubber are extruded from a screw type extruder, and then the sheets are laminated to form a bale.

The thickness of the dry rubber sheet 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, most preferably 5 to 25 mm. It is excellent in workability and productivity and suitable for certain occasions. In particular, since the thermal conductivity of the dry rubber sheet is as low as 0.15 to 0.35 W/mK, the thickness of the dry rubber sheet is usually 1 to 30 mm when the cooling efficiency is increased and the productivity is significantly improved. The range is preferably 2 to 25 mm, more preferably 3 to 15 mm, particularly preferably 4 to 12 mm.

The width of the dry rubber sheet extruded from the screw-type extruder is appropriately selected according to the purpose of use, and is usually in the range of 300-1200 mm, preferably 400-1000 mm, more preferably 500-800 mm.

The temperature of the dry rubber sheet 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, more preferably 120 to 160°C.

The complex viscosity at 100°C of the dry rubber sheet extruded from the screw extruder ([η] 100°C) is not particularly limited, but is usually 1,500 to 6,000 Pa s, preferably 2 ,000 to 5,000 Pa s, more preferably 2,500 to 4,000 Pa s, most preferably 2,500 to 3,500 Pa s, extrudability and shape retention as a sheet and are highly balanced. That is, when the content is at least the lower limit, extrudability can be improved, and when the content is at or below the upper limit, deformation and breakage of the dry rubber sheet can be suppressed.

In the present invention, the dry rubber sheet extruded from the screw-type extruder is preferably laminated and baleed after being cut, because the amount of air involved is small and the storage stability is excellent. The method of cutting the dry rubber sheet is not particularly limited, but since the acrylic rubber of the acrylic rubber veil of the present invention has strong adhesiveness, the dry rubber sheet is cut continuously without entraining air. It is preferable to carry out after cooling.

The cutting temperature of the dry rubber sheet is not particularly limited, but is usually 60° C. or lower, preferably 55° C. or lower, and more preferably 50° C. or lower, because cuttability and productivity are highly balanced. is.

The complex viscosity ([η] 60° C.) of the dry rubber sheet at 60° C. is not particularly limited, but is usually 15,000 Pa s or less, preferably 2,000 to 10,000 Pa s, or more. Preferably, the pressure is in the range of 2,500 to 7,000 Pa·s, most preferably 2,700 to 5,500 Pa·s, so that continuous cutting can be performed without entrainment of air.

The ratio ([η]100°C/[η]60°C) of the complex viscosity of the dry rubber sheet at 100°C ([η]100°C) and the complex viscosity at 60°C ([η]60°C) is Although there are no particular limitations, the air It is preferable because there is little entanglement and cutting and productivity are highly balanced.

The method for cooling the dry rubber sheet is not particularly limited, and it may be left at room temperature. Forced cooling, such as an air-cooling system under cooling, a water-spraying system, or an immersion system in which water is immersed, is preferable for increasing productivity, and air-cooling under ventilation or cooling is particularly preferable.

In the air-cooling method for sheet-like dry rubber, for example, the sheet-like dry rubber can be extruded from a screw type extruder onto a conveying machine such as a belt conveyor, and then 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, more preferably 10 to 20°C. The length to be cooled is not particularly limited, but is usually in the range of 5-500m, preferably 10-200m, more preferably 20-100m. The cooling rate of the dry rubber sheet is not particularly limited, but cutting is particularly easy when it is usually 50° C./hr or higher, more preferably 100° C./hr or higher, and more preferably 150° C./hr or higher. and is suitable.

The cut length of the dry rubber sheet is not particularly limited, and may be appropriately selected according to the size of the acrylic rubber veil to be produced. is in the range of

The sheet-like dried rubber after being cut is laminated and integrated into a bale. The lamination temperature of the dry rubber sheet is not particularly limited, but it is usually 30° C. or higher, preferably 35° C. or higher, more preferably 40° C. or higher, so that the air entrained during lamination can be released. The number of layers to be laminated may be appropriately selected according to the size or weight of the acrylic rubber veil.

The thus-obtained acrylic rubber veil of the present invention is superior in operability and storage stability to crumb-like acrylic rubber. can be used.

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

The filler is not particularly limited, but examples thereof include reinforcing fillers and non-reinforcing fillers, preferably reinforcing fillers.

Examples of reinforcing fillers 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 non-reinforcing fillers include quartz powder, diatomaceous earth, zinc white, basic magnesium carbonate, activated 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. The amount to be blended is appropriately selected within a range that does not impair the effects of the present invention. The range is generally 1 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 20 to 100 parts by weight.

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

When the acrylic rubber veil to be used is composed of a carboxyl group-containing acrylic rubber, it is preferable to use a polyvalent amine compound and its carbonate as a cross-linking agent. Examples of polyvalent amine compounds include aliphatic polyvalent amine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexanediamine; 4,4'-methylenedianiline, p -phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-(m-phenylenediisopropylidene) 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-xyl aromatic polyvalent amine compounds such as diamine, p-xylylenediamine, 1,3,5-benzenetriamine; Among these, hexamethylenediaminecarbamate, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane and the like are preferred.

When the acrylic rubber veil to be used is composed of an epoxy group-containing acrylic rubber, aliphatic polyvalent amine compounds such as hexamethylenediamine and hexamethylenediamine carbamate, and their carbonates as cross-linking agents; 4,4'-methylene Aromatic polyvalent amine compounds such as dianiline; ammonium benzoate, ammonium adipate and its carboxylic acid ammonium salts; dithiocarbamate metal salts such as zinc dimethyldithiocarbamate; polyvalent carboxylic acids such as tetradecanedioic acid; cetyltrimethylammonium bromide quaternary onium salts such as; imidazole compounds such as 2-methylimidazole; isocyanuric acid compounds such as ammonium isocyanurate; is more preferred.

When the acrylic rubber veil to be used is composed of a halogen atom-containing acrylic rubber, it is preferable to use sulfur, a sulfur donor, or a triazinethiol compound as a cross-linking agent. Examples of sulfur donors include dipentamethylenethiuram hexasulfide and triethylthiuram disulfide. Triazine compounds include, for example, 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 preferred.

These cross-linking agents may be used alone or in combination of two or more. The amount to be blended is usually 0.001 to 20 parts by weight, preferably 0.1 part per 100 parts by weight of the acrylic rubber veil. ~10 parts by weight, more preferably 0.1 to 5 parts by weight. By setting the amount of the cross-linking agent within this range, it is possible to make the cross-linked rubber product excellent in mechanical strength while ensuring sufficient rubber elasticity.

In the rubber mixture of the present invention, rubber components other than the acrylic rubber veil can be used as necessary.

Other rubber components used as necessary are not particularly limited. Elastomers, styrene-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, polysiloxane-based elastomers, and the like can be mentioned. The shape of the other rubber component is not particularly limited, and may be, for example, crumb-like, sheet-like, or veil-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 may optionally contain an anti-aging agent. Anti-aging agents include, but are not limited to, 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-triazin-2-ylamino)phenol; tris(nonylphenyl) Phosphite ester antioxidants such as phosphite, diphenylisodecyl phosphite, tetraphenyldipropylene glycol diphosphite; sulfur ester antioxidants such as dilauryl thiodipropionate; phenyl-α-naphthylamine, phenyl-β- naphthylamine, p-(p-toluenesulfonylamido)-diphenylamine, 4,4'-(α,α-dimethylbenzyl)diphenylamine, N,N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p - amine-based antioxidants such as phenylenediamine and butyraldehyde-aniline condensates; imidazole-based antioxidants such as 2-mercaptobenzimidazole; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, etc. quinoline antioxidants; hydroquinone antioxidants such as 2,5-di-(t-amyl) hydroquinone; Among these, amine anti-aging agents are particularly preferred.

These anti-aging agents can be used alone or in combination of two or more. It ranges from 1 to 10 parts by weight, more preferably from 1 to 5 parts by weight.

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

<Method for producing rubber mixture>
The method for producing the rubber mixture is not particularly limited, but includes a method of mixing the acrylic rubber veil of the present invention with the filler, the cross-linking agent, and the other ingredients that can be contained as necessary. For mixing, any means conventionally used in the field of rubber processing, such as open rolls, Banbury mixers and various kneaders, can be used. That is, using these mixers, the acrylic rubber veil, the filler, the cross-linking agent, etc. can be mixed directly, preferably by direct kneading.

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

There are no particular restrictions on the mixing procedure for each component, but for example, after thoroughly mixing components that are difficult to react or decompose with heat, the cross-linking agent, which is a component that easily reacts or decomposes with heat, should not react or decompose. Two-step mixing is preferred, which mixes for a short period of time at a low temperature. Specifically, it is preferable to mix the cross-linking agent in the second step after mixing the acrylic rubber veil and the filler in the first step. Other rubber components and antioxidants are usually mixed in the first stage, the cross-linking accelerator 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, more preferably 25 to 80. is.

<Rubber cross-linked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the above rubber mixture.

The rubber cross-linked product of the present invention is obtained by molding the rubber mixture of the present invention into a desired shape using a molding machine such as an extruder, an injection molding machine, a compressor, a roll, etc., and heating the cross-linked rubber. It can be produced by reacting and fixing the shape as a rubber crosslinked product. In this case, the cross-linking may be performed after pre-molding, or the cross-linking may be performed at the same time as the molding. The molding temperature is usually 10-200°C, preferably 25-150°C. The crosslinking temperature is usually 100 to 250°C, preferably 130 to 220°C, more preferably 150 to 200°C, and the crosslinking time is usually 0.1 minute 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 cross-linked rubber product of the present invention may be subjected to secondary cross-linking by further heating depending on the shape, size, etc. of the cross-linked rubber product. The secondary cross-linking is preferably carried out for 1 to 48 hours, although it varies depending on the heating method, cross-linking temperature, shape and the like. A heating method and a heating temperature may be appropriately selected.

The rubber cross-linked product of the present invention is a seal material for, for example, O-rings, packings, diaphragms, oil seals, shaft seals, bearing sheaths, mechanical seals, well head seals, seals for electric/electronic devices, and seals for air compression devices. A unit cell equipped with a rocker cover gasket attached to the connection between the cylinder block and the cylinder head, an oil pan gasket attached to the connection 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 fuel cell separator gaskets and hard disk drive top cover gaskets installed between a pair of sandwiched housings; cushioning materials, anti-vibration materials; wire coating materials; industrial belts; tubes and hoses; ; and the like are suitably used.

The crosslinked rubber product of the present invention can also be used as extrusion molding products and mold crosslinked products for use in automobiles, such as fuel hoses, filler neck hoses, vent hoses, paper hoses, fuel tanks such as oil hoses, etc. Air system hoses such as system hoses, turbo air hoses, mission control hoses, radiator hoses, heater hoses, brake hoses, air conditioner hoses, etc.

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

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

The emulsion polymerization reactor is configured to perform the emulsion polymerization process described above. Although not shown in FIG. 1, the emulsion polymerization reactor has, for example, a polymerization reactor, a temperature controller for controlling the reaction temperature, and a stirring device equipped with a motor and stirring blades. In the emulsion polymerization reactor, water and a phosphoric acid-based emulsifier are mixed with the monomer component for forming the acrylic rubber, emulsified while being stirred appropriately with a stirrer, and emulsion polymerization is performed in the presence of a polymerization catalyst. An emulsion polymerization liquid can be obtained. The emulsion polymerization reactor may be of a batch type, a semi-batch type, or a continuous type, and may be either a tank reactor or a tubular reactor.

The coagulation device 3 shown in FIG. 1 is configured to perform the above-described coagulation process. As schematically illustrated 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, a temperature control unit (not shown) for controlling the temperature inside the stirring tank 30, It has a stirring device 34 having a motor 32 and stirring blades 33 and a drive control unit (not shown) for controlling the rotation speed and rotation speed of the stirring blades 33 . In the coagulation device 3, the emulsion polymerization liquid obtained in the emulsion polymerization reactor is brought into contact with a coagulation liquid as a coagulant to be coagulated, thereby producing water-containing crumbs.

In the coagulation device 3, for example, the emulsion polymerization liquid and the coagulation liquid are brought into contact with each other by adding the emulsion polymerization liquid to the agitated magnesium salt aqueous solution. That is, the stirring tank 30 of the coagulation device 3 is filled with a coagulating liquid, and the emulsion polymerization liquid is added to and brought into contact with the coagulating liquid to solidify the emulsion polymerization liquid, thereby producing water-containing crumbs.

The heating unit 31 of the coagulation device 3 is configured to heat the coagulation liquid filled in the stirring vessel 30 . Further, the temperature control unit of the coagulation device 3 controls the heating operation of the heating unit 31 while monitoring the temperature in the agitation vessel 30 measured by a thermometer, thereby controlling the temperature in the agitation vessel 30. It is configured. The temperature of the coagulation liquid in the stirring vessel 30 is controlled by the temperature control section so that it is usually 40°C or higher, preferably 40 to 90°C, and more preferably 50 to 80°C.

The stirring device 34 of the coagulation device 3 is configured to stir the coagulation liquid filled in the stirring tank 30 . Specifically, the stirring device 34 includes a motor 32 that generates rotational power and stirring blades 33 that extend in a direction perpendicular to the rotating shaft of the motor 32 . The stirring impeller 33 can cause the solidified liquid to flow in the solidified liquid filled in the stirring tank 30 by rotating around the rotating shaft by the rotational power of the motor 32 . The shape, size, and number of the stirring blades 33 are not particularly limited.

The drive control section of the coagulation device 3 is configured to control the rotational drive of the motor 32 of the stirring device 34 to set the rotational speed and rotational speed of the stirring blades 33 of the stirring device 34 to predetermined values. The rotation of the stirring blades 33 is controlled by the drive control unit so that the stirring speed of the coagulated liquid is usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm, and particularly preferably 400 to 800 rpm. be done. The peripheral speed of the coagulation liquid is usually 0.5 m/s or higher, preferably 1 m/s or higher, more preferably 1.5 m/s or higher, particularly preferably 2 m/s or higher, and most preferably 2.5 m/s or higher. Rotation of the stirring blade 33 is controlled by the drive control unit so that Furthermore, the driving control unit stirs so that the upper limit of the peripheral speed of the coagulation liquid 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. Rotation of the wings 33 is controlled.

The cleaning device 4 shown in FIG. 1 is configured to perform the cleaning process described above. As schematically illustrated in FIG. 1, the cleaning apparatus 4 includes, for example, a cleaning tank 40, a heating unit 41 for heating the inside of the cleaning tank 40, and a temperature control unit (not shown) for controlling the temperature inside the cleaning tank 40. have. In the washing device 4, the water-containing crumbs produced in the coagulating device 3 are mixed with a large amount of water and washed, thereby effectively reducing the amount of ash in the finally obtained acrylic rubber veil.

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

The water-containing crumbs washed by the washing device 4 are supplied to a screw type extruder 5 which performs a dehydration step and a drying step. At this time, the washed wet crumbs are preferably supplied to the screw extruder 5 through a drainer 43 capable of separating free water. A wire mesh, a screen, an electric sieve, or the like can be used as the drainer 43, for example.

When the washed wet crumbs are supplied to the screw extruder 5, the temperature of the wet crumbs 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 crumbs supplied to the screw extruder 5 can be maintained at 60° C. or higher. Alternatively, the wet crumbs may be heated to a temperature of 40° C. or higher, preferably 60° C. or higher when conveyed from the washing device 4 to the screw extruder 5 . As a result, it becomes possible to effectively carry out the dehydration process and the drying process, which are post-processes, and to significantly reduce the moisture content of the finally obtained dry rubber.

The screw-type extruder 5 shown in FIG. 1 is configured to perform the above-described dehydration process and drying process. Although FIG. 1 shows a screw extruder 5 as a suitable example, a centrifugal separator, a squeezer, or the like may be used as a dehydrator for performing the dehydration process, and the drying process may be performed. A hot air dryer, a reduced pressure dryer, an expander dryer, a kneader dryer, or the like may be used as a dryer for drying.

The screw extruder 5 is configured to mold the dried rubber obtained through the dehydration process and the drying process into a predetermined shape and to discharge the molded product. Specifically, the screw-type extruder 5 includes a dehydrating barrel section 53 having a function as a dehydrator for dehydrating the water-containing crumbs washed by the washing device 4, and a dryer having a function as a dryer for drying the water-containing crumbs. A barrel portion 54 is provided, and a die 59 having a forming function of forming a wet crumb is provided on the downstream side of the screw extruder 5 .

The configuration of the screw extruder 5 will be described below with reference to FIG. FIG. 2 shows the configuration of a specific example suitable for the screw extruder 5 shown in FIG. With this screw type extruder 5, the dehydration/drying process described above can be performed favorably.

The screw extruder 5 shown in FIG. 2 is a twin-screw extrusion dryer having a pair of screws (not shown) in a barrel unit 51 . The screw extruder 5 has a drive unit 50 that drives a pair of screws in a barrel unit 51 to rotate. The drive unit 50 is attached to the upstream end (the left end in FIG. 2) of the barrel unit 51 . The screw extruder 5 also has a die 59 at the downstream end of the barrel unit 51 (the right end in FIG. 2).

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

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

The dewatering barrel section 53 is composed of three dewatering barrels, that is, a first dewatering barrel 53a, a second dewatering barrel 53b and a third dewatering barrel 53c.

Also, the drying barrel section 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 drying barrel 54f, a seventh drying barrel 54g, and an eighth drying barrel 54h.

Thus, the barrel unit 51 is constructed by connecting 13 divided barrels 52a-52b, 53a-53c, 54a-54h from the upstream side to the downstream side.

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

The number of supply barrels, dehydration barrels, and drying barrels that constitute the respective barrel portions 52, 53, and 54 in the barrel unit 51 is not limited to the embodiment shown in FIG. The number can be set according to the water content of the wet crumbs.

For example, the number of supply barrels installed in the supply barrel section 52 is, for example, one to three. Further, the number of dewatering barrels installed in the dewatering barrel section 53 is preferably, for example, 2 to 10, and more preferably 3 to 6, since water-containing crumbs of sticky acrylic rubber can be efficiently dewatered. The number of drying barrels installed in the drying barrel section 54 is preferably 2 to 10, more preferably 3 to 8, for example.

A pair of screws in the barrel unit 51 are rotationally driven by drive means such as a motor housed in the drive unit 50 . The pair of screws extends 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 mixed and conveyed downstream. It's like The pair of screws is preferably of a biaxially meshing type in which the crests and troughs are meshed with each other, whereby the dehydration efficiency and drying efficiency of the water-containing crumbs can be enhanced.

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

The feed barrel section 52 is a region for feeding wet crumbs into the barrel unit 51 . A first feed barrel 52 a of the feed barrel section 52 has a feed port 55 for feeding wet crumbs into the barrel unit 51 .

The dewatering barrel portion 53 is a region for separating and discharging a liquid (cerum water) containing a coagulant or the like from the water-containing crumb.

The first to third dewatering barrels 53a to 53c constituting the dewatering barrel section 53 respectively have dewatering slits 56a, 56b, 56c for discharging the moisture of the water-containing crumbs to the outside. A plurality of dewatering slits 56a, 56b, 56c are formed in each of the dewatering barrels 53a to 53c.

The slit width, that is, the opening of each of the dewatering slits 56a, 56b, and 56c may be appropriately selected according to the conditions of use, and is usually 0.01 to 5 mm, which reduces the loss of water-containing crumbs and reduces the loss of water-containing crumbs. It is preferably 0.1 to 1 mm, more preferably 0.2 to 0.6 mm, from the viewpoint of efficient dehydration.

Moisture is removed from the water-containing crumbs in the dehydration barrels 53a to 53c of the dehydration barrel section 53 in two ways: removal in a liquid state from the dehydration slits 56a, 56b, and 56c, and removal in a vapor state. . In the dehydration barrel section 53 of the present embodiment, the case of removing moisture in liquid form is defined as drainage, and the case of removing moisture in vapor form is defined as exhaust steam.

In the dehydration barrel section 53, it is possible to efficiently reduce the moisture content of the adhesive acrylic rubber by combining drainage and exhaust steam, which is suitable. In the dehydration barrel section 53, which one of the first to third dehydration barrels 53a to 53c is used for discharging water or steam may be appropriately set according to the purpose of use. If the amount of ash in the acrylic rubber is to be reduced, the number of dewatering barrels for discharging water should be increased. In this case, for example, as shown in FIG. 2, the first and second dehydration barrels 53a and 53b on the upstream side are used to drain water, and the third dehydration barrel 53c on the downstream side is used to discharge steam. Further, for example, when the dehydration barrel section 53 has four dehydration barrels, it is conceivable that three dehydration barrels on the upstream side perform drainage and one dehydration barrel on the downstream side exhausts steam. On the other hand, if the moisture content is to be reduced, the number of dehydration barrels for discharging steam should be increased.

The set temperature of the dehydration barrel section 53 is usually in the range of 60 to 150° C., preferably 70 to 140° C., more preferably 80 to 130° C., as described in the above dehydration/drying process. The set temperature of the dehydration barrel for dehydration is usually 60 to 120°C, preferably 70 to 110°C, more preferably 80 to 100°C. , preferably 105 to 140°C, more preferably 110 to 130°C.

The drying barrel section 54 is an area for drying the dewatered wet crumbs under reduced pressure. Among the first to eighth drying barrels 54a to 54h constituting the drying barrel section 54, the second drying barrel 54b, the fourth drying barrel 54d, the sixth drying barrel 54f and the eighth drying barrel 54h are It has vent ports 58a, 58b, 58c and 58d for degassing, respectively. Vent pipes (not shown) are connected to the vent ports 58a, 58b, 58c, and 58d, respectively.

A vacuum pump (not shown) is connected to the end of each vent pipe, and the inside of the drying barrel section 54 is decompressed to a predetermined pressure by the operation of these vacuum pumps. The screw extruder 5 has pressure control means (not shown) for controlling the operation of the vacuum pumps to control the degree of pressure reduction in the drying barrel section 54 .

The degree of pressure reduction in the drying barrel section 54 may be appropriately selected, but as described above, it is usually set to 1 to 50 kPa, preferably 2 to 30 kPa, more preferably 3 to 20 kPa.

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

In each of the drying barrels 54a to 54h constituting the drying barrel section 54, the set temperature in all the drying barrels 54a to 54h may be set to approximate values or may be different, but the upstream side (dehydration barrel section It is preferable to set the temperature on the downstream side (die 59 side) to be higher than the temperature on the side of 53, 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 predetermined nozzle-shaped discharge port. The acrylic rubber dried in the drying barrel 54 is extruded into a shape corresponding to a predetermined nozzle shape by passing through the outlet of the die 59 . The acrylic rubber passing through the die 59 is formed into various shapes such as grains, columns, rods, and sheets depending on the shape of the nozzle of the die 59 . For example, by making the discharge port of the die 59 substantially rectangular, acrylic rubber can be extruded into a sheet. 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, water-containing crumbs of raw material acrylic rubber are extruded into sheet-like dry rubber in the following manner.

The water-containing crumbs of acrylic rubber obtained through the washing process are supplied from the feed port 55 to the supply barrel section 52 . The wet crumbs supplied to the supply barrel section 52 are sent from the supply barrel section 52 to the dewatering barrel section 53 by the rotation of the pair of screws in the barrel unit 51 . In the dehydration barrel section 53, water contained in the water-containing crumbs is drained and steam is discharged from the dehydration slits 56a, 56b, and 56c provided in the first to third dehydration barrels 53a to 53c, respectively, as described above. , the wet crumb is dewatered.

The wet crumbs dehydrated in the dewatering barrel section 53 are sent to the drying barrel section 54 by the rotation of the pair of screws in the barrel unit 51 . The water-containing crumbs sent to the drying barrel section 54 are plasticized and mixed to become a melt, and are carried downstream while generating heat and increasing the temperature. Then, the water contained in the melted acrylic rubber evaporates, and the water (steam) is discharged to the outside through vent pipes (not shown) connected to the respective vent ports 58a, 58b, 58c, and 58d.

By passing through the drying barrel section 54 as described above, the water-containing crumbs are dried and become 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. is extruded from die 59 as dry rubber.

Here, an example of operating conditions of the screw extruder 5 according to this 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, which can efficiently reduce the water content and gel amount of the acrylic rubber veil. From the point of view, it is preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120 to 300 rpm.

The extrusion rate (Q) of the 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.

In addition, the ratio (Q/N) between the extrusion rate (Q) of the acrylic rubber and the number of revolutions (N) of the screw is not particularly limited, but is usually 1 to 20, preferably 2 to 10, more preferably 2 to 10. 3 to 8, with 4 to 6 being particularly preferred.

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

As described above, depending on the shape of the nozzle of the die 59, the dried rubber discharged from the screw extruder 5 is extruded into various shapes such as granules, columns, rods, and sheets. Hereinafter, as an example of the cooling device 6, a conveying type cooling device 60 for cooling the sheet-shaped dry rubber 10 molded 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 conveying type cooling device 60 shown in FIG. 3 is configured to cool the dry rubber sheet 10 discharged from the discharge port of the die 59 of the screw type extruder 5 by an air cooling system while conveying it. By using this transport-type cooling device 60, the sheet-like dry rubber discharged from the screw extruder 5 can be cooled appropriately.

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

The conveying type cooling device 60 has a conveyer 61 that conveys the dry rubber sheet 10 discharged from the die 59 of the screw type extruder 5 in the direction of arrow A in FIG. It has a cooling means 65 for blowing.

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

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

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

According to the conveying type cooling device 60 shown in FIG. The dry rubber sheet 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. It is good also as a structure provided with the cooling means 65 of this. In that case, the total length of each of the two or more conveyors 61 and the cooling means 65 should be within the above range.

The baling device 7 shown in FIG. 1 is configured to process the dry rubber extruded from the screw extruder 5 and cooled by the cooling device 6 to produce a baled block. As described above, the screw-type extruder 5 can extrude dry rubber into various shapes such as granules, columns, rods, and sheets. It is configured to bale dry rubber that has been shaped into a shape. Although the weight and shape of the acrylic rubber bale produced by the bale forming device 7 are not particularly limited, for example, a substantially rectangular parallelepiped acrylic rubber bale weighing about 20 kg is produced.

The baling device 7 may be equipped with, for example, a baler, and the acrylic rubber bales may be produced by compressing the cooled dry rubber with the baler.

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

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

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. "Parts", "%" and "ratios" in each example are by weight unless otherwise specified.

Various physical properties were evaluated according to the following methods.

[Monomer composition]
Regarding the monomer composition in the acrylic rubber, the monomer composition of each monomer unit in the acrylic rubber was confirmed by H-NMR, and it was confirmed that the activity of the reactive group remained in the acrylic rubber and that each group The reactive group content was confirmed by the following test method.

The content of each monomer unit in the acrylic rubber was calculated from the amount of each monomer used in the polymerization reaction and the polymerization conversion rate. Specifically, the polymerization reaction was an emulsion polymerization reaction, and the polymerization conversion rate was approximately 100% in which no unreacted monomer could be confirmed. It was assumed to be the same as the amount used for the body.

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

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

[Ash content]
The amount (ppm) of each component in the ash content of the acrylic rubber veil was measured by pressing the ash content collected for the difference in the ash content measurement described above to a φ20 mm titration filter paper and performing XRF measurement using ZSX Primus (manufactured by Rigaku).

[Gel amount]
The gel amount (%) of the acrylic rubber veil is the amount of insoluble matter in methyl ethyl ketone, and was obtained by the following method.

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

[specific gravity]
The specific gravity of the acrylic rubber veil was measured in accordance with JIS K6268 Crosslinked Rubber—Method A for Density Measurement.

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

[pH]
The pH of the acrylic rubber veil was measured with a pH electrode after dissolving 6 g (±0.05 g) of acrylic rubber veil in 100 g of tetrahydrofuran, adding 2.0 ml of distilled water, and confirming complete dissolution.

[Water content]
The water content (%) of the acrylic rubber veil was measured according to JIS K6238-1: Oven A (volatile content measurement) method.

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

[Complex viscosity]
The complex viscosity η of the acrylic rubber veil was measured using a dynamic viscoelasticity measuring device "Rubber Process Analyzer RPA-2000" (manufactured by Alpha Technology Co., Ltd.) with a strain of 473% and temperature dispersion (40 to 120 ° C) at 1 Hz. was measured, and the complex viscosity η at each temperature was determined. Here, the dynamic viscoelasticity at 60°C of the above dynamic viscoelasticity is defined as the complex viscosity η (60°C), and the dynamic viscoelasticity at 100°C is defined as the complex viscosity η (100°C), where η (100 °C)/η(60°C) and η(60°C)/η(100°C) were calculated.

[Mooney viscosity (ML1+4, 100°C)]
The Mooney viscosity (ML1+4, 100° C.) of the acrylic rubber veil was measured according to JIS K6300 Uncrosslinked Rubber Physical Test Method.

[Storage stability evaluation]
The storage stability of the rubber sample was evaluated by placing the rubber sample in a constant temperature and humidity chamber (SH-222, manufactured by ESPEC) at 45°C and 80% RH, and using the rubber sample before and after the test for 7 days to determine the Mooney scorch of the rubber mixture. The minimum viscosity (Vm) was measured at 125° C. using an L rotor according to JIS K6300-1:2013, and the rate of change after test loss was calculated. The Vm change rate was evaluated by an index with the change rate of Comparative Example 2 being 100 (the smaller the index, the better the storage stability).

[Water resistance evaluation]
The water resistance of a rubber sample was tested by immersing a cross-linked rubber sample in distilled water at a temperature of 85°C for 100 hours in accordance with JIS K6258. It was evaluated by an index with 2 as 100 (the lower the index, the better the water resistance).
Volume change rate before and after immersion (%) = ((test piece volume after immersion - test piece volume before immersion) / test piece volume before immersion) x 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 rubber cross-linked product of the rubber sample according to JIS K6251.
(1) Breaking strength was evaluated as ⊚ when 10 MPa or more and x when less than 10 MPa.
(2) The 100% tensile stress was evaluated as ⊚ when 5 MPa or more and x when less than 5 MPa.
(3) Elongation at break was evaluated as ⊚ when 150% or more and x when less than 150%.

[Example 1]
In a mixing vessel equipped with a homomixer, 46 parts of pure water, 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and nonylphenyl as an emulsifier 1.8 parts of oxyhexaoxyethylene phosphate sodium salt was 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 reactor equipped with a thermometer and a stirrer, and cooled to 12° C. under a nitrogen stream. Next, the remainder 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 dropped into the polymerization reactor over 3 hours. bottom. After that, the reaction was continued while maintaining the temperature in the polymerization reaction at 23° C., and after confirming that the polymerization conversion reached approximately 100%, hydroquinone was added as a polymerization terminator to terminate the polymerization reaction. to obtain an emulsion polymerization liquid.

In a coagulation tank equipped with a thermometer and a stirring device, the emulsion polymerization obtained in a 2% magnesium sulfate aqueous solution (coagulation liquid) heated to 80 ° C. and vigorously stirred (600 rotations: peripheral speed 3.1 m / s) The liquid was heated to 80° C. and continuously added to solidify the polymer and filtered to obtain water-containing crumbs.

Next, 194 parts of hot water (70°C) was added to the coagulation tank, stirred for 15 minutes, and then water was discharged. washed. The washed wet crumbs were supplied to a screw extruder, dehydrated and dried to extrude a dry rubber sheet having a width of 300 mm and a thickness of 10 mm. Next, the sheet-like dried rubber was cooled at a cooling rate of 200° C./hr using a conveying type cooling device directly connected to the screw type extruder.

The screw extruder used in Example 1 has one feed 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 dewatering barrels are for draining and the third dewatering barrel is for venting. The operating conditions of the screw type extruder were as follows.

Water content:
- Moisture content of the wet crumb after draining in the second dewatering barrel: 20%
- Moisture content of the wet crumb after steam discharge in the third dehydration barrel: 10%
Rubber temperature:
- Temperature of the wet crumb fed to the first feed barrel: 65°C
・Temperature of rubber discharged from screw type extruder: 140°C
Set temperature for 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
- 5th drying barrel: 180°C
Operating conditions:
・Diameter (D) of the screw in the barrel unit: 132mm
・Total length of screw in barrel unit (L): 4620mm
・L/D: 35
・Rotation speed of the screw in the barrel unit: 135 rpm
・Extrusion rate of rubber from die: 700 kg/hr
・Die resin pressure: 2 MPa

The extruded dry rubber sheet was cooled to 50°C, cut with a cutter, and laminated so as to make 20 parts (20 kg) before reaching 40°C or less to obtain an acrylic rubber veil (A). . Reactive group content, ash content, ash component content, specific gravity, gel content, pH, glass transition temperature (Tg), water content, molecular weight, molecular weight distribution, complex viscosity and Mooney of the obtained acrylic rubber veil (A) Viscosity (ML1+4, 100° C.) was measured and the results are shown in Table 2.

Next, using a Banbury mixer, 100 parts of the acrylic rubber veil (A) and compounding agent A of "Formulation 1" shown in Table 1 were added and mixed at 50°C for 5 minutes.

Next, the obtained mixture was transferred to a roll at 50° C., and compounding agent B of “Formulation 1” shown in Table 1 was mixed to obtain a rubber mixture. The Mooney scorch minimum viscosity (Vm) of a rubber mixture prepared in the same manner using the obtained rubber mixture and the acrylic rubber veil (A) after the storage stability test was measured, and the rate of change is shown in Table 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 pressed at 180° C. for 10 minutes under a pressure of 10 MPa for primary cross-linking. The primary cross-linked product was further heated in a gear oven at 180° C. for 2 hours for secondary cross-linking to obtain a sheet-like cross-linked rubber product. Then, a test piece of 3 cm×2 cm×0.2 cm was cut out from the obtained sheet-like cross-linked rubber product and evaluated for water resistance and physical properties under normal conditions.

[Example 2]
42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile and 1.3 parts of vinyl chloroacetate as the monomer components; An acrylic rubber veil (B) was obtained in the same manner as in Example 1 except for changing to oxyethylene phosphate sodium salt, and each property (changed to "Formulation 2") was evaluated. Those results are shown in Table 2.

[Example 3]
The temperature of the first dehydration barrel of the screw 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 in the first dehydration barrel, and in the first dehydration barrel An acrylic rubber veil (C) was obtained in the same manner as in Example 1 except that the water content of the water-containing crumb after drainage was changed to 30%, and each characteristic was evaluated. Those results are shown in Table 2.

[Example 4]
The temperature of the first dehydration barrel of the screw 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 in the first dehydration barrel, and in the first dehydration barrel An acrylic rubber veil (D) was obtained in the same manner as in Example 2 except that the water content of the water-containing crumbs after drainage was changed to 30%, and each characteristic was evaluated. Those results are shown in Table 2.

[Example 5]
After the washing process was carried out in the same manner as in Example 1, the washed crumbs were dried in a hot air dryer at 160° C. to obtain crumb-like dried rubber having a water content of 0.4% by weight. 20 parts (20 kg) of the obtained crumb-shaped dried rubber was filled in a baler of 300×650×300 mm and compacted under a pressure of 3 MPa for 30 seconds to obtain an acrylic rubber veil (E). Each characteristic of the obtained acrylic rubber veil (E) was evaluated, and the results are shown in Table 2.

[Example 6]
After carrying out the washing process in the same manner as in Example 2, the washed crumbs were dried in a hot air dryer at 160° C. to obtain crumb-like dried rubber having a water content of 0.4% by weight. 20 parts (20 kg) of the obtained crumb-shaped dried rubber was filled in a 300×650×300 mm baler and pressed for 30 seconds at a pressure of 3 MPa to obtain an acrylic rubber veil (F). Each characteristic of the obtained acrylic rubber veil (F) was evaluated, and the results are shown in Table 2.

[Example 7]
In the coagulation step, acrylic rubber veil (G) was obtained in the same manner as in Example 6 except that the stirring speed of the 2% magnesium sulfate aqueous solution (coagulation liquid) was changed to 100 rpm and the peripheral speed was changed to 0.5 m / s, and each characteristic was measured. It was evaluated and shown in Table 2.

[Example 8]
In the coagulation step, an acrylic rubber veil (G) was obtained in the same manner as in Example 7 except that the coagulation liquid was changed to a 0.7% magnesium sulfate aqueous solution.

[Comparative Example 1]
The coagulation reaction in the coagulation step was performed by continuously adding a 0.7% aqueous magnesium sulfate solution to the emulsion polymerization liquid obtained by emulsion polymerization to generate water-containing crumbs, and by not baling with a baler after hot air drying. A crumb-like acrylic rubber (I) was obtained in the same manner as in Example 8 except for the above. Each characteristic of the crumb-like acrylic rubber (I) was evaluated and the results are shown in Table 2.

[Comparative Example 2]
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, and 1.3 parts of vinyl chloroacetate were placed in a mixing vessel equipped with a homomixer. , 0.709 parts of sodium lauryl sulfate and 1.82 parts of polyoxyethylene dodecyl ether (molecular weight: 1500) as emulsifiers 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 reactor equipped with a thermometer and a stirrer, and cooled to 12° C. under a nitrogen stream. Next, the remainder 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 dropped into the polymerization reactor over 3 hours. bottom. After that, the reaction was continued while maintaining the temperature in the polymerization reaction at 23° C., and after confirming that the polymerization conversion reached approximately 100%, hydroquinone was added as a polymerization terminator to terminate the polymerization reaction. to obtain an emulsion polymerization liquid.

Next, after heating the emulsion polymerization liquid to 80° C., a 0.7% sodium sulfate aqueous solution (coagulating liquid) was continuously added to the emulsion polymerization liquid (rotation speed: 100 rpm, peripheral speed: 0.5 m/s). The polymer was coagulated and filtered to obtain wet crumbs. 194 parts of industrial water was added to 100 parts of the resulting water-containing crumbs, and the mixture was stirred at 25°C for 5 minutes. After that, the water-containing crumbs were washed four times to drain water from the coagulation tank, and then an aqueous solution of pH 3 sulfuric acid. After adding 194 parts and stirring at 25 ° C. for 5 minutes, water was discharged from the coagulation tank and acid washing was performed once. C. to obtain a crumb-like acrylic rubber (J) having a water content of 0.4% by weight. Each property of the obtained crumb-like acrylic rubber (J) was evaluated and shown in Table 2.

From Table 2, it can be seen that acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000 has an ash content of 0.8% by weight or less and a phosphorus content in the ash of 10% by weight. % or more and a specific gravity of 0.8 or more, the acrylic rubber veils (A) to (H) are found to be excellent in storage stability and water resistance (Examples 1 to 8).

Regarding storage stability, the rate of change in Mooney scorch minimum viscosity (Vm) before and after being placed in a constant temperature and humidity chamber at 45°C x 80% RH was evaluated. is superior to the crumb-like acrylic rubbers (I) to (J) (comparison between Examples 1 to 8 and Comparative Examples 1 to 2). Among acrylic rubber veils (A) to (H), acrylic rubber veils (A) to (H) have outstanding storage stability, and acrylic rubber veils (E) to (H) have excellent storage stability. (Comparison between Examples 1 to 4 and Examples 5 to 8), all relationships including comparative examples (acrylic rubber veils (A) to (D) >> acrylic rubber veils (E) to (H) >> It can be seen that the crumb-like acrylic rubbers (I) to (J) correlate with the specific gravity of rubber properties (Examples 1 to 8 and Comparative Examples 1 to 2). The specific gravity is related to the amount of air entrained, and the acrylic rubber veils (A) to (D), which have an overwhelmingly large specific gravity, are in a state in which they contain almost no air, so they can be stored against oxidation deterioration. It seems to have excellent stability.

Regarding water resistance, first, it can be seen that the amount of ash remaining in the crumb-like acrylic rubber is significantly greater when the phosphoric acid emulsifier is used than when the sulfuric acid emulsifier is used (comparison with Comparative Examples 1 and 2). However, by adding the obtained emulsion polymerization liquid to the coagulation liquid being stirred from the method of adding the coagulation liquid to the emulsion polymerization liquid obtained by emulsion polymerization of the coagulation method (Comparative Example 1), even if the washing method is the same, it will remain. It can be seen that the ash content is significantly reduced and the water resistance is improved (comparison between Comparative Example 1 and Example 8). Furthermore, the coagulant concentration of the coagulating liquid being stirred is changed to 2%, the rotation speed is 600 rpm, the peripheral speed is changed to 3.1 m / s, and the conditions are changed to a certain degree of vigorous stirring, and the water-containing crumb It can be seen that the ash content is remarkably reduced and the water resistance is improved by performing dehydration by squeezing the water out (Examples 1 to 8).

As for the water resistance, it can be seen that the acrylic rubber veil of the present invention is remarkably improved in water resistance, although the ash content is not so different from that of the crumb-like acrylic rubber using a sulfuric acid-based emulsifier. . This is one that uses a phosphoric acid emulsifier, particularly one that uses a combination of Group 2 metal salts of the periodic table as a coagulant, more preferably a divalent phosphate emulsifier as an emulsifier and a magnesium salt as a coagulant. Although the amount of ash remaining when using is not very small (difficult to wash off), it does not affect the water resistance, so the acrylic rubber veils (A) to (H) of the present invention are used. It is considered that the water resistance is remarkably excellent (comparison between Examples 1 to 8 and Comparative Example 2).

With regard to water resistance, acrylic rubber veils (A), (C) and (E) in which the reactive group has an ion-reactive group such as an epoxy group are further combined with acrylic rubber veils (B) and (B) in which the reactive group has a chlorine atom. It is found to be superior to D) and (F) (Examples 1 to 6).

From Table 2, further, reactive group amount, specific gravity, gel amount, glass transition temperature (Tg), pH, water content, weight average molecular weight (Mw), z average molecular weight (Mz) and weight average molecular weight (Mw) ratio (Mz/Mw ), complex viscosity η at 100°C (100°C), complex viscosity η at 60°C (60°C), ratio of complex viscosity at 100°C and 60°C (η100°C/η60°C), and Acrylic rubber veils (A) to (H) having a Mooney viscosity (1 + 4, 100 ° C.) within a specific range are excellent in storage stability and water resistance, and are also excellent in strength properties (normal physical properties) ( Examples 1-8).

1 acrylic rubber manufacturing system 3 coagulating device 4 washing device 5 screw extruder 6 cooling device 7 bale forming device

Claims (8)

Made of acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, an ash content of 0.2% by weight or less, and a phosphorus content in the ash content of 10% by weight or more. and an acrylic rubber veil having a gel amount of 10 % by weight or less and a specific gravity of 0.8 or more. 2. The acrylic rubber veil according to claim 1, wherein the ash contains phosphorus and magnesium, and the total amount of phosphorus and magnesium in the ash is 30% by weight or more. an emulsion polymerization step in which a monomer component containing a (meth)acrylic acid ester and a reactive group-containing monomer is emulsified with water and a phosphoric acid-based emulsifier and emulsion polymerized in the presence of a polymerization catalyst to obtain an emulsion polymerization liquid;
a coagulation step of contacting the obtained emulsion polymerization liquid and the coagulation liquid to generate water-containing crumbs;
a washing step for washing the produced hydrous crumbs;
A drying step of drying the washed wet crumbs to a moisture content of less than 1% by weight using a screw extruder to extrude dry rubber;
2. The method for producing an acrylic rubber veil according to claim 1, further comprising a baling step of laminating the extruded dry rubber to form a veil. 4. The method for producing an acrylic rubber veil according to claim 3, wherein the coagulating liquid is an aqueous magnesium salt solution. 5. The method for producing an acrylic rubber veil according to claim 3 or 4, further comprising a dehydration step of squeezing water out of the washed water-containing crumbs. The method for producing an acrylic rubber veil according to any one of claims 3 to 5, wherein the dry rubber to be extruded is sheet-shaped dry rubber, and the sheet-shaped dry rubber is laminated for baling. A rubber mixture obtained by mixing the acrylic rubber veil according to claim 1 or 2 with a filler and a cross-linking agent. A cross-linked rubber obtained by cross-linking the rubber mixture according to claim 7.

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