WO2023026841A1 - Method for producing acrylic rubber - Google Patents

Method for producing acrylic rubber Download PDF

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Publication number
WO2023026841A1
WO2023026841A1 PCT/JP2022/030307 JP2022030307W WO2023026841A1 WO 2023026841 A1 WO2023026841 A1 WO 2023026841A1 JP 2022030307 W JP2022030307 W JP 2022030307W WO 2023026841 A1 WO2023026841 A1 WO 2023026841A1
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mass
parts
acrylic polymer
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latex
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PCT/JP2022/030307
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French (fr)
Japanese (ja)
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慧二 北原
辰哉 中野
俊明 宮内
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デンカ株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/10—Esters
    • C08F20/12—Esters of monohydric alcohols or phenols
    • C08F20/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F20/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F6/00—Post-polymerisation treatments
    • C08F6/14—Treatment of polymer emulsions
    • C08F6/22—Coagulation

Definitions

  • the present invention relates to a method for producing acrylic rubber.
  • Acrylic rubber and its crosslinked products have excellent physical properties such as heat resistance, oil resistance, and mechanical properties, so they are used as materials for hoses and sealing parts in automobile engine compartments, for example.
  • Acrylic rubber can be obtained, for example, by emulsion-polymerizing a monomer to obtain an acrylic polymer and then solidifying the acrylic polymer. Since such a method for producing an acrylic rubber can affect various physical properties of the obtained acrylic rubber, a suitable production method is used depending on the desired physical properties.
  • Patent Document 1 as a method for producing an acrylic rubber having excellent water resistance and compression set resistance when crosslinked, a monomer containing (meth)acrylic acid ester as a main component is added to a polymerization catalyst in the presence of an emulsifier.
  • An object of the present invention is to provide a method for producing an acrylic rubber that can reduce the compression set of a crosslinked acrylic rubber.
  • the present inventors have found that in the method for producing acrylic rubber, if the concentration of the acrylic polymer obtained by emulsion polymerization is changed when the acrylic polymer is coagulated with a coagulant, the composition of the monomers constituting the acrylic polymer remains the same. Also, it was found that the compression set of the obtained crosslinked acrylic rubber differs, and that the compression set becomes small when the concentration of the acrylic polymer is within a predetermined range.
  • One aspect of the present invention is the step of emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifier to obtain an acrylic polymer, and mixing a latex containing the acrylic polymer and the emulsifier with a coagulating liquid containing a coagulant. and coagulating the acrylic polymer, wherein the content of the acrylic polymer in the mixture of the latex and the coagulating liquid is 20% by mass or less based on the total amount of the mixture.
  • the content of the acrylic polymer in the latex may be 30% by mass or more based on the total amount of latex, and the mass ratio of the content of the coagulating liquid to the content of the latex in the mixture may be 0.6 or more.
  • the content of the acrylic polymer in the latex may be less than 30% by mass based on the total amount of latex.
  • the monomer may further contain a cross-linking site monomer.
  • the cross-linking monomer may be a cross-linking monomer having a carboxyl group.
  • One embodiment of the present invention comprises a step of emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifier to obtain an acrylic polymer (polymerization step), a latex containing the acrylic polymer and the emulsifier, and a coagulant containing the coagulant. and a step of solidifying the acrylic polymer by mixing it with a liquid (solidifying step).
  • the monomers are emulsion-polymerized in the presence of an emulsifier by a known emulsion polymerization method.
  • a suspension is prepared by mixing a monomer (a mixture of monomers when two or more monomers are used) and an aqueous solution of an emulsifier in a reaction vessel. Subsequently, after the inside of the reaction vessel is replaced with nitrogen gas, the suspension is stirred while a polymerization initiator is added to the suspension to initiate polymerization, for example, at 40 to 100° C. for 1 to 24 hours. proceed.
  • Alkyl acrylate contained in the monomer forms the skeleton of the acrylic rubber.
  • Alkyl acrylates include, for example, one or more alkyl acrylates having an alkyl group with 1 to 8 carbon atoms.
  • the alkyl group may be linear or branched.
  • the content of alkyl acrylate, based on the total amount of monomers, may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and 99% by mass or less, 98% by mass or less, or 97% by mass. % by mass or less.
  • the alkyl acrylate may include, for example, an alkyl acrylate having an alkyl group having 1 to 3 carbon atoms (hereinafter also referred to as “C1-C3 alkyl acrylate”), and an alkyl acrylate having an alkyl group having 4 to 8 carbon atoms (hereinafter “ (also referred to as “C4-C8 alkyl acrylates”).
  • C1-C3 alkyl acrylates examples include methyl acrylate, ethyl acrylate, and n-propyl acrylate. From the viewpoint of improving the tensile strength of the acrylic rubber, the C1-C3 alkyl acrylate preferably contains at least one selected from the group consisting of methyl acrylate and ethyl acrylate, more preferably ethyl acrylate.
  • the content of C1-C3 alkyl acrylate is 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass, based on the total amount of monomers. or more, and may be 95% by mass or less, 90% by mass or less, or 80% by mass or less.
  • C4-C8 alkyl acrylates include, for example, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-methylpentyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate.
  • the alkyl acrylate preferably contains butyl acrylate, more preferably n-butyl acrylate, from the viewpoint of improving the cold resistance of the acrylic rubber.
  • the content of C4-C8 alkyl acrylate, based on the total amount of monomers, may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 80% by mass or less, 70% by mass or less, or 60% by mass. may be:
  • Alkyl acrylates preferably include at least one selected from the group consisting of C1-C3 alkyl acrylates and at least one selected from the group consisting of C4-C8 alkyl acrylates, more preferably methyl acrylate or ethyl acrylate, n-butyl acrylate, more preferably ethyl acrylate and n-butyl acrylate.
  • the monomer may further contain other monomers copolymerizable with the alkyl acrylate.
  • Other monomers may be alkyl methacrylates, for example.
  • Alkyl methacrylates include, for example, one or more alkyl methacrylates having an alkyl group of 1 to 12 carbon atoms.
  • the alkyl group may be linear or branched.
  • Alkyl methacrylates preferably include alkyl methacrylates having alkyl groups of 1 to 8 carbon atoms, more preferably alkyl groups of 1 to 4 carbon atoms.
  • alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and n-decyl methacrylate. , and n-dodecyl methacrylate.
  • Alkyl methacrylate preferably contains at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate, more preferably methyl methacrylate, ethyl methacrylate, and It contains at least one selected from the group consisting of n-butyl methacrylate, more preferably n-butyl methacrylate.
  • the content of alkyl methacrylate may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total amount of monomers. you can
  • the other monomer may be, for example, vinyl acetate.
  • the content of vinyl acetate may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total amount of monomers. you can
  • the other monomer may be, for example, a cross-linking monomer.
  • a cross-linking site monomer is a monomer that is copolymerizable with an alkyl acrylate and has a functional group that forms a cross-linking site (also referred to as a cross-linking point).
  • Cross-linking monomers have polymerizable carbon-carbon double bonds, such as acryloyl, methacryloyl, allyl, methallyl, vinyl, or alkenylene groups.
  • the functional groups include epoxy groups, carboxyl groups, and active chlorine groups.
  • the cross-linking monomer may have one or more of these functional groups.
  • the cross-linking site monomer is from the viewpoint that the effect of reducing the compression set of the cross-linked acrylic rubber (details will be described later) can be particularly preferably obtained by setting the content of the acrylic polymer in the mixture in the coagulation step to a predetermined range. Therefore, it is preferably a crosslinking site monomer having a carboxyl group.
  • the cross-linking monomer having an epoxy group preferably has a glycidyl group.
  • Cross-linkable monomers having epoxy groups include, for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methallyl glycidyl ether.
  • the number of carboxyl groups in the crosslinking site monomer having a carboxyl group may be one, two, or three or more.
  • Examples of crosslinking monomers having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid, itaconic acid, and maleic acid monoalkyl esters.
  • cross-linkable monomers having active chlorine groups examples include 2-chloroethyl vinyl ether, 2-chloroethyl acrylate, vinylbenzyl chloride, vinyl chloroacetate, and allyl chloroacetate.
  • the content of the crosslinking site monomer is 0.5 parts by mass or more, 0.8 parts by mass or more, 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass with respect to 100 parts by mass of the total amount of monomers other than the crosslinking site monomer. or more, and may be 10 parts by mass or less, 7 parts by mass or less, or 5 parts by mass or less.
  • Other monomers include, for example, ethylene, alkoxyalkyl (meth)acrylates, fluorine-containing (meth)acrylates, hydroxyl group-containing (meth)acrylates, tertiary amino group-containing (meth)acrylates, alkyl vinyl ketones, vinyl ethers, allyl ethers, It may be an aromatic vinyl compound, vinyl nitrile, vinyl halide, vinylidene halide, or the like. The content of these other monomers may be 1% by mass or more and 10% by mass or less based on the total amount of monomers.
  • the emulsifier may be a known emulsifier used in the above emulsion polymerization.
  • the emulsifier may be, for example, a nonionic emulsifier.
  • the nonionic emulsifier may contain at least one selected from the group consisting of an ether nonionic emulsifier, an ester nonionic emulsifier, an ether ester nonionic emulsifier, a nitrogen-containing nonionic emulsifier, and a polyvinyl alcohol emulsifier.
  • ether-type nonionic emulsifiers include polyoxyethylene alkyl ethers, polyoxyethylene alkylallyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene alkylphenol ethers, and polyoxyethylene polyoxypropylene copolymers. , polyoxyethylene lauryl glycol, and polyoxypropylene glycol.
  • ester-type nonionic emulsifiers examples include sorbitan fatty acid esters and glycerin fatty acid esters.
  • Sorbitan fatty acid esters may be, for example, monoesters.
  • Glycerin fatty acid esters may be, for example, monoesters or diesters.
  • ether ester-type nonionic emulsifiers include polyoxyethylene fatty acid esters and polyoxyethylene sorbitan fatty acid esters.
  • Polyoxyethylene fatty acid esters may be, for example, monoesters or diesters.
  • Polyoxyethylene sorbitan fatty acid esters can be, for example, monoesters.
  • nitrogen-containing nonionic emulsifiers include polyoxyethylene alkylamines, polyoxyethylene fatty acid monoethanolamides, and fatty acid diethanolamides.
  • the polyvinyl alcohol-based emulsifier may be fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol, preferably partially saponified polyvinyl alcohol.
  • the degree of saponification of polyvinyl alcohol is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, preferably 100 mol% or less, more preferably 99 mol% or less, still more preferably It is 90 mol % or less.
  • the saponification degree of polyvinyl alcohol means a value measured according to JIS K6726 "3.5 saponification degree".
  • the amount of the emulsifier added may be, for example, 0.1 parts by mass or more and may be 10 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
  • the polymerization initiator is, for example, an azo compound such as azobisisobutyronitrile, an organic peroxide such as tert-butyl hydroperoxide, cumene hydroperoxide, or benzoyl peroxide, or an inorganic peroxide such as sodium persulfate or ammonium persulfate. It may be a peroxide, preferably tert-butyl hydroperoxide.
  • the amount of the polymerization initiator added may be, for example, 0.01 parts by mass or more and may be 2 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
  • a pH adjuster may be added to the suspension.
  • the pH adjuster may be, for example, an alkali metal salt such as sodium acetate, sodium hydroxide, potassium hydroxide, sodium phosphate, sodium citrate, preferably sodium acetate.
  • the amount of the pH adjuster added may be, for example, 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
  • FIG. 1 is a schematic diagram showing an example of the extruder.
  • the extruder 1 comprises a coagulation zone 2, a first drainage zone 3, a first washing zone 4, a second drainage zone 5, a second washing zone 6 and a third A drainage zone 7 and a drying zone 8 are provided in this order.
  • a latex L containing an acrylic polymer and an emulsifier and a coagulating liquid C containing a coagulant are respectively supplied to the coagulating zone 2, and the latex L and the coagulating liquid C are mixed to coagulate the acrylic polymer.
  • the coagulating liquid C may be, for example, an aqueous solution containing a coagulant, or an aqueous solution consisting only of a coagulant and water.
  • the content of the coagulant in the coagulant liquid C is set so that an appropriate amount of coagulant is added according to the amount of the acrylic polymer.
  • the amount of the coagulating liquid added may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more relative to 100 parts by mass of the acrylic polymer, and may be 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass. It may be less than or equal to parts by mass.
  • the content of the coagulant in the coagulating liquid C may be set so as to be such an amount to be added. Above, 4% by mass or more, or 5% by mass or more, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less good
  • Coagulants include, for example, ammonium salts, monovalent to trivalent metal salts, inorganic acids, and organic acids.
  • Ammonium salts include, for example, ammonium borate, ammonium sulfate, and ammonium chloride.
  • monovalent to trivalent metal salts include sodium salts, magnesium salts, calcium salts, aluminum salts, and zinc salts.
  • Sodium salts include, for example, sodium borate, sodium sulfate, and sodium chloride.
  • Magnesium salts include, for example, magnesium sulfate, magnesium chloride, and magnesium nitrate.
  • Calcium salts include, for example, calcium sulfate, calcium chloride, and calcium nitrate.
  • Aluminum salts include, for example, aluminum sulfate and aluminum chloride.
  • Zinc salts include, for example, zinc chloride and zinc acetate.
  • Inorganic acids include, for example, hydrochloric acid, sulfuric acid, and nitric acid.
  • Organic acids include, for example, formic acid and acetic acid.
  • the latex L and the coagulation liquid C are supplied to the coagulation zone 2 so that the content of the acrylic polymer in the mixture of the latex L and the coagulation liquid C is 20% by mass or less based on the total amount of the mixture.
  • the compression set of the obtained crosslinked acrylic rubber can be reduced. It is speculated that the reason why such an effect is obtained is that the emulsifier coexisting with the acrylic polymer can be easily removed in the washing step described below due to the small content of the acrylic polymer.
  • the content of the acrylic polymer in the mixture is preferably 19% by mass or less, 17% by mass or less, 15% by mass or less, based on the total amount of the mixture, from the viewpoint that the compression set of the crosslinked acrylic rubber can be further reduced. % by mass or less, 14% by mass or less, 13% by mass or less, 12% by mass or less, 11% by mass or less, or 10% by mass or less.
  • the content of the acrylic polymer in the mixture is 5% by mass or more, 6% by mass or more, 7% by mass or more, 8% by mass or more, 9% by mass or more, or 10% by mass or more, based on the total amount of the mixture. good too.
  • the content of the acrylic polymer in the mixture is adjusted by adjusting the content of the acrylic polymer in the latex L and the mixing ratio of the latex L and the coagulating liquid C in the mixture (in other words, the amount of the latex L and the coagulating liquid C supplied). By doing so, it is possible to make it within the above range.
  • the reaction product (containing the acrylic polymer and the emulsifier) obtained in the polymerization step may be used as it is, and the content of the acrylic polymer in the latex L may be adjusted by diluting the reaction product with water, for example. It may be used after
  • the content of the acrylic polymer in the latex L is 30% by mass or more, 31% by mass or more, 32% by mass or more, 33% by mass or more, 34% by mass or more, or 35% by mass or more, based on the total amount of the latex L. It may be at least 50% by mass, and may be at most 50% by mass.
  • the mass ratio of the content of the coagulating liquid C to the content of the latex L in the mixture is preferably 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.5 or more, 1.8 or more, 2 or more, or 2.2 or more , for example 4 or less.
  • the compression set of the crosslinked acrylic rubber can be reduced, and the yield of the acrylic rubber can be increased.
  • the content of the acrylic polymer in the latex L is less than 30% by mass, 25% by mass or less, 20% by mass or less, 17% by mass or less, or 15% by mass or less based on the total amount of the latex L.
  • it may be 10% by mass or more.
  • the mass ratio of the content of the coagulating liquid C to the content of the latex L in the mixture is, for example, 0.1 or more, 0.2 or more, or 0.3 or more.
  • the compression set of the crosslinked acrylic rubber can be further reduced.
  • the method for producing acrylic rubber comprises a coagulation step followed by a first drainage step, a first washing step, a second drainage step, a second washing step, a third drainage step, and a drying step. and may be further provided in this order. Each of these steps is carried out while extruding the acrylic polymer solidified in the solidification zone 2 by rotating the screw of the extruder 1 .
  • the screw rotation speed of the extruder 1 may be, for example, 40 rpm or more and may be 200 rpm or less.
  • the screw of the extruder 1 is rotated to dehydrate the solidified acrylic polymer, and the drainage D1 is performed from the drainage slit.
  • the solidified acrylic polymer is washed to remove impurities (emulsifier, coagulants, unreacted substances, etc.) are removed.
  • the cleaning liquid W1 may be water, for example.
  • the screw of the extruder 1 is rotated to dewater the solidified acrylic polymer, and the drainage D2 is performed from the drainage slit.
  • the screw of the extruder 1 is rotated while supplying the washing liquid W2 to further wash the solidified acrylic polymer to remove impurities (emulsifiers) in the solidified acrylic polymer. , coagulants, unreacted substances, etc.) are further removed.
  • the cleaning liquid W2 may be water, for example.
  • the screw of the extruder 1 is rotated to dewater the solidified acrylic polymer, and the drainage D3 is performed from the drainage slit.
  • the total amount of the cleaning liquids W1 and W2 supplied in the first cleaning step and the second cleaning step may be, for example, 250 parts by mass or more and 800 parts by mass or less with respect to 100 parts by mass of the acrylic polymer. you can
  • the solidified acrylic polymer is dried in the drying zone 8 by, for example, heating under reduced pressure conditions.
  • the pressure of the decompression condition may be, for example, 90 kPa or less and may be 50 kPa or more.
  • Heating is performed, for example, by raising the temperature of the drying zone 8 and raising the head of the extruder 1 .
  • the temperature of the drying zone 8 may be, for example, 105° C. or higher and 200° C. or lower.
  • the temperature of the head of the extruder 1 may be, for example, 130° C. or higher and 200° C. or lower.
  • the acrylic rubber R is extruded from the extruder 1 to obtain the acrylic rubber R.
  • the acrylic rubber thus obtained may be used as a rubber composition by mixing with additives as necessary.
  • Another embodiment of the present invention is a rubber composition comprising a step of obtaining an acrylic rubber by the above-described method for producing an acrylic rubber, and a step of mixing the acrylic rubber and an additive to obtain a rubber composition. manufacturing method.
  • the content of the acrylic rubber may be, for example, 50% by mass or more, 55% by mass or more, or 60% by mass or more, and may be 90% by mass or less based on the total amount of the rubber composition.
  • Additives include, for example, fillers, lubricants, antioxidants, surfactants, cross-linking agents, and cross-linking accelerators.
  • Fillers include, for example, carbon black, silica, talc and calcium carbonate.
  • the content of the filler may be, for example, 30 parts by mass or more and may be 100 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • Lubricants include, for example, liquid paraffin, stearic acid, stearylamine, fatty acid zinc, fatty acid esters, and organosilicones.
  • the content of the lubricant may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • Anti-aging agents include, for example, aromatic amine compounds and phenol compounds.
  • the content of the anti-aging agent may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • surfactants include alkyl sulfate salts.
  • the content of the surfactant may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • cross-linking agents examples include imidazole compounds and diamine compounds.
  • the content of the cross-linking agent may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • a cross-linking accelerator is preferably used when the rubber composition contains a cross-linking agent.
  • cross-linking accelerators include trimethylthiourea compounds, phenothiazine compounds, aliphatic monovalent secondary amine compounds, aliphatic monovalent tertiary amine compounds, quaternary onium salts, tertiary phosphine compounds, and weakly acidic alkali metals. Salts, diazabicycloalkene compounds and guanidine compounds are included.
  • the content of the crosslinking accelerator may be, for example, 0.1 parts by mass or more and may be 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
  • the rubber composition is preferably used in a crosslinked state (as a crosslinked product).
  • Another embodiment of the present invention comprises steps of obtaining an acrylic rubber by the above-described method for producing an acrylic rubber, mixing the acrylic rubber and an additive to obtain a rubber composition, and cross-linking the rubber composition. and obtaining a crosslinked product of a rubber composition.
  • the method for cross-linking the rubber composition may be a known method.
  • the step of obtaining a crosslinked product may comprise, for example, a first crosslinking step of heating and pressurizing the rubber composition, and a second crosslinking step of further heating the rubber composition after the first crosslinking step.
  • the heating temperature may be, for example, 150°C or higher and 220°C or lower.
  • the pressure during pressurization may be, for example, 0.4 MPa or more and may be 20 MPa or less.
  • the time for heating and pressurizing may be, for example, 5 minutes or more and 2 hours or less.
  • the heating temperature may be, for example, 150°C or higher and 220°C or lower.
  • the heating time may be, for example, 30 minutes or longer and may be 24 hours or shorter.
  • the cross-linking sites (cross-linking points) of the cross-linking site monomer form cross-links between the acrylic rubbers.
  • the rubber composition contains a cross-linking agent
  • cross-linking between the acrylic rubbers is further formed by the cross-linking agent.
  • the monomer constituting the acrylic rubber does not contain a cross-linking site monomer and the rubber composition contains a cross-linking agent
  • cross-linking between the acrylic rubbers is formed by the cross-linking agent.
  • a crosslinked product of a rubber composition is particularly suitable for use as sealing parts such as rubber hoses, gaskets, and packings.
  • rubber hoses include transmission oil cooler hoses for automobiles, construction machinery, hydraulic equipment, engine oil cooler hoses, air duct hoses, turbo hoses, hot air hoses, radiator hoses, power steering hoses, fuel system hoses, and drain systems. hoses, etc.
  • the crosslinked product of the rubber composition containing acrylic rubber obtained by the above production method is particularly suitable for turbo hoses and sealing parts because it is excellent in terms of compression set.
  • Seal parts include, for example, engine head cover gaskets, oil pan gaskets, oil seals, lip seal packings, O-rings, transmission seal gaskets, crankshafts, camshaft seal gaskets, valve stems, power steering seal belt cover seals, constant velocity Boot materials for joints and rack and pinion boot materials are included.
  • Examples 1-1 to 1-4 and Comparative Example 1-1> Manufacture of acrylic rubber
  • 11 kg of a monomer mixture consisting of 70 parts by mass of ethyl acrylate, 30 parts by mass of n-butyl acrylate, and 2.66 parts by mass of monobutyl maleate, and 4% by mass of partially saponified polyvinyl alcohol as an emulsifier were placed in a pressure-resistant reaction vessel having an internal volume of 40 liters.
  • 17 kg of an aqueous solution (degree of saponification of polyvinyl alcohol: 88 mol %) and 22 g of sodium acetate were added and thoroughly mixed in advance with a stirrer to prepare a uniform suspension.
  • Water is added as necessary to the reaction solution after the completion of the reaction to contain the acrylic polymer in the amount shown in Table 1 (% by mass based on the total amount of latex) (further containing the above-described emulsifier, etc.) do) got latex.
  • a coagulant a mixture of 1.25 parts by mass of sodium borate, 2.25 parts by mass of ammonium sulfate, and 3.75 parts by mass of ammonium borate was used, and the content of this mixture (coagulant) is shown in Table 1.
  • a solidified liquid was obtained by dissolving in water so that the amount (% by mass based on the total amount of the solidified liquid) was obtained.
  • an extruder 1 twin-screw kneading extruder, TEM-50, manufactured by Toshiba Machine Co., Ltd.
  • TEM-50 twin-screw kneading extruder, manufactured by Toshiba Machine Co., Ltd.
  • the acrylic polymer was drained D1 in the first drainage zone 3 .
  • using water as the cleaning liquids W1 and W2 washing with water D2 in the first washing zone 4 and drainage D2 in the second drainage zone 5, washing with water in the second cleaning zone 6 and drainage D3 in the third drainage zone 7 and were performed sequentially.
  • the total amount of water used in the first washing zone 4 and the second washing zone 6 was 430 parts by weight per 100 parts by weight of the acrylic polymer.
  • acrylic rubber was obtained by heating the acrylic polymer under reduced pressure (80 kPa) (temperature in drying zone 8: 150°C, temperature of extruder head: 155°C).
  • the acrylic polymer content (% by mass) in the mixture of latex and coagulating liquid shown in Table 1 was calculated by the following formula.
  • Content of acrylic polymer in the mixture F A /(F L +F C ) x 100
  • F A Supply amount of acrylic polymer (kg/h)
  • F L Amount of latex supplied (kg/h)
  • F C Amount of coagulation liquid supplied (kg/h) and F A was calculated by the following formula.
  • F A F L ⁇ C A /100
  • C A Content of acrylic polymer in latex (% by mass) is.
  • Examples 2-1 to 2-2 and Comparative Example 2-1> In the production of acrylic rubber, the procedure was the same as in Example 1-1, except that the composition of the monomer mixture was changed to 80 parts by mass of ethyl acrylate, 20 parts by mass of n-butyl acrylate, and 4.00 parts by mass of monobutyl maleate. , production of acrylic rubber, preparation of rubber composition, and evaluation of compression set. Table 2 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (the relative value of the compression set of each example when the compression set of Comparative Example 2-1 is set to 100).
  • Example 3-1 and Comparative Example 3-1 In the production of acrylic rubber, except that the composition of the monomer mixture was changed to 46 parts by weight of ethyl acrylate, 26 parts by weight of n-butyl acrylate, 28 parts by weight of n-butyl methacrylate, and 4.00 parts by weight of monobutyl maleate. Production of acrylic rubber, preparation of rubber composition, and evaluation of compression set were carried out in the same manner as in Example 1-1. Table 3 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (relative value of the compression set of the example when the compression set of Comparative Example 3-1 is set to 100).
  • Examples 4-1 to 4-2 and Comparative Example 4-1> In the production of acrylic rubber, changing the composition of the monomer mixture to 20.9 parts by weight of vinyl acetate, 10.4 parts by weight of methyl acrylate, 68.7 parts by weight of n-butyl acrylate, and 1.55 parts by weight of glycidyl methacrylate, An acrylic rubber was produced in the same manner as in Example 1-1, except that the coagulant was changed to a mixture of 2.5 parts by mass of sodium borate and 1.5 parts by mass of ammonium sulfate.
  • Example 4 For each rubber composition obtained, the compression set was evaluated in the same manner as in Example 1-1. Table 4 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (the relative value of the compression set of each example when the compression set of Comparative Example 4-1 is set to 100).

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Abstract

A method for producing an acrylic rubber, the method comprising: a step for obtaining an acrylic polymer by emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifying agent; and a step for solidifying the acrylic polymer by mixing a latex that contains the acrylic polymer and the emulsifying agent with a solidification liquid that contains a solidifying agent. With respect to this method for producing an acrylic rubber, the content of the acrylic polymer in the mixture of the latex and the solidification liquid is 20% by mass or less based on the total amount of the mixture.

Description

アクリルゴムの製造方法Method for manufacturing acrylic rubber
　本発明は、アクリルゴムの製造方法に関する。 The present invention relates to a method for producing acrylic rubber.
　アクリルゴム及びその架橋物は、耐熱性、耐油性、機械的特性等の物性に優れているため、例えば自動車のエンジンルーム内のホースやシール部品等の材料として使用されている。アクリルゴムは、例えば、モノマーを乳化重合してアクリルポリマーを得た後、当該アクリルポリマーを凝固させることで得られる。このようなアクリルゴムの製造方法は、得られるアクリルゴムの種々の物性に影響を与え得るため、所望の物性に応じて適した製造方法が用いられる。 Acrylic rubber and its crosslinked products have excellent physical properties such as heat resistance, oil resistance, and mechanical properties, so they are used as materials for hoses and sealing parts in automobile engine compartments, for example. Acrylic rubber can be obtained, for example, by emulsion-polymerizing a monomer to obtain an acrylic polymer and then solidifying the acrylic polymer. Since such a method for producing an acrylic rubber can affect various physical properties of the obtained acrylic rubber, a suitable production method is used depending on the desired physical properties.
　例えば特許文献１には、架橋した時の耐水性及び耐圧縮永久歪み性に優れるアクリルゴムの製造方法として、（メタ）アクリル酸エステルを主成分とする単量体を乳化剤の存在下に重合触媒を用いて乳化重合し乳化重合液を得る乳化重合工程と、乳化重合液をポリエチレングリコールの存在下で凝固し含水クラムを得る凝固工程と、含水クラムに対して洗浄する洗浄工程と、洗浄した含水クラムを乾燥する乾燥工程と、を備えるアクリルゴムの製造方法が開示されている。 For example, in Patent Document 1, as a method for producing an acrylic rubber having excellent water resistance and compression set resistance when crosslinked, a monomer containing (meth)acrylic acid ester as a main component is added to a polymerization catalyst in the presence of an emulsifier. An emulsion polymerization step of obtaining an emulsion polymerization liquid by emulsion polymerization using, a coagulation step of coagulating the emulsion polymerization liquid in the presence of polyethylene glycol to obtain water-containing crumbs, a washing step of washing the water-containing crumbs, and a washed water-containing and a drying step for drying the crumbs.
特開２０１９－１８９８３５号公報JP 2019-189835 A
　本発明者らの検討によれば、アクリルゴムの架橋物の圧縮永久ひずみを小さくするためには、アクリルゴムの製造方法において更なる改善の余地がある。本発明の目的は、アクリルゴムの架橋物の圧縮永久ひずみを小さくすることが可能なアクリルゴムの製造方法を提供することである。 According to the studies of the present inventors, there is room for further improvement in the production method of acrylic rubber in order to reduce the compression set of the crosslinked acrylic rubber. An object of the present invention is to provide a method for producing an acrylic rubber that can reduce the compression set of a crosslinked acrylic rubber.
　本発明者らは、アクリルゴムの製造方法において、乳化重合により得られたアクリルポリマーを凝固剤により凝固させる際のアクリルポリマーの濃度を変更すると、アクリルポリマーを構成するモノマーの組成が同じであっても、得られるアクリルゴムの架橋物の圧縮永久ひずみに違いが生じること、更には、アクリルポリマーの濃度が所定の範囲であると当該圧縮永久ひずみが小さくなることを見出した。 The present inventors have found that in the method for producing acrylic rubber, if the concentration of the acrylic polymer obtained by emulsion polymerization is changed when the acrylic polymer is coagulated with a coagulant, the composition of the monomers constituting the acrylic polymer remains the same. Also, it was found that the compression set of the obtained crosslinked acrylic rubber differs, and that the compression set becomes small when the concentration of the acrylic polymer is within a predetermined range.
　本発明の一側面は、アルキルアクリレートを含むモノマーを乳化剤の存在下で乳化重合してアクリルポリマーを得る工程と、アクリルポリマー及び乳化剤を含有するラテックスと、凝固剤を含有する凝固液とを混合して、アクリルポリマーを凝固させる工程と、を備え、ラテックスと凝固液との混合物中のアクリルポリマーの含有量が、混合物全量を基準として２０質量％以下である、アクリルゴムの製造方法である。 One aspect of the present invention is the step of emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifier to obtain an acrylic polymer, and mixing a latex containing the acrylic polymer and the emulsifier with a coagulating liquid containing a coagulant. and coagulating the acrylic polymer, wherein the content of the acrylic polymer in the mixture of the latex and the coagulating liquid is 20% by mass or less based on the total amount of the mixture.
　ラテックス中のアクリルポリマーの含有量が、ラテックス全量を基準として３０質量％以上であり、混合物中のラテックスの含有量に対する凝固液の含有量の質量比が０．６以上であってよい。 The content of the acrylic polymer in the latex may be 30% by mass or more based on the total amount of latex, and the mass ratio of the content of the coagulating liquid to the content of the latex in the mixture may be 0.6 or more.
　ラテックス中のアクリルポリマーの含有量は、ラテックス全量を基準として３０質量％未満であってよい。 The content of the acrylic polymer in the latex may be less than 30% by mass based on the total amount of latex.
　モノマーは、架橋席モノマーを更に含んでよい。架橋席モノマーは、カルボキシル基を有する架橋席モノマーであってよい。 The monomer may further contain a cross-linking site monomer. The cross-linking monomer may be a cross-linking monomer having a carboxyl group.
　本発明によれば、アクリルゴムの架橋物の圧縮永久ひずみを小さくすることが可能なアクリルゴムの製造方法を提供できる。 According to the present invention, it is possible to provide a method for producing acrylic rubber that can reduce the compression set of a crosslinked product of acrylic rubber.
一実施形態における凝固工程及びそれ以降の工程を実施するための押出機の一例を示す模式図である。It is a mimetic diagram showing an example of an extruder for carrying out a solidification process and subsequent processes in one embodiment.
　本発明の一実施形態は、アルキルアクリレートを含むモノマーを乳化剤の存在下で乳化重合してアクリルポリマーを得る工程（重合工程）と、アクリルポリマー及び乳化剤を含有するラテックスと、凝固剤を含有する凝固液とを混合して、アクリルポリマーを凝固させる工程（凝固工程）と、を備えるアクリルゴムの製造方法である。 One embodiment of the present invention comprises a step of emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifier to obtain an acrylic polymer (polymerization step), a latex containing the acrylic polymer and the emulsifier, and a coagulant containing the coagulant. and a step of solidifying the acrylic polymer by mixing it with a liquid (solidifying step).
　重合工程では、公知の乳化重合法により、乳化剤の存在下でモノマーを乳化重合する。具体的には、例えば、モノマー（二種以上のモノマーが用いられる場合はモノマー混合物）と乳化剤の水溶液とを反応容器内で混合して懸濁液を作製する。続いて、反応容器中を窒素ガスで置換した後、懸濁液を撹拌しながら、重合開始剤を懸濁液に加えて重合を開始させ、例えば４０～１００℃で１～２４時間で重合を進行させる。 In the polymerization process, the monomers are emulsion-polymerized in the presence of an emulsifier by a known emulsion polymerization method. Specifically, for example, a suspension is prepared by mixing a monomer (a mixture of monomers when two or more monomers are used) and an aqueous solution of an emulsifier in a reaction vessel. Subsequently, after the inside of the reaction vessel is replaced with nitrogen gas, the suspension is stirred while a polymerization initiator is added to the suspension to initiate polymerization, for example, at 40 to 100° C. for 1 to 24 hours. proceed.
　モノマーに含まれるアルキルアクリレートは、アクリルゴムの骨格となるものである。アルキルアクリレートは、例えば、炭素数１～８のアルキル基を有するアルキルアクリレートの一種又は二種以上を含む。当該アルキル基は、直鎖状であっても分岐状であってもよい。 The alkyl acrylate contained in the monomer forms the skeleton of the acrylic rubber. Alkyl acrylates include, for example, one or more alkyl acrylates having an alkyl group with 1 to 8 carbon atoms. The alkyl group may be linear or branched.
　アルキルアクリレートの含有量は、モノマー全量を基準として、６０質量％以上、７０質量％以上、８０質量％以上、又は９０質量％以上であってよく、９９質量％以下、９８質量％以下、又は９７質量％以下であってよい。 The content of alkyl acrylate, based on the total amount of monomers, may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and 99% by mass or less, 98% by mass or less, or 97% by mass. % by mass or less.
　アルキルアクリレートは、例えば、炭素数１～３のアルキル基を有するアルキルアクリレート（以下「Ｃ１－Ｃ３アルキルアクリレート」ともいう）を含んでよく、炭素数４～８のアルキル基を有するアルキルアクリレート（以下「Ｃ４－Ｃ８アルキルアクリレート」ともいう）を含んでもよい。 The alkyl acrylate may include, for example, an alkyl acrylate having an alkyl group having 1 to 3 carbon atoms (hereinafter also referred to as "C1-C3 alkyl acrylate"), and an alkyl acrylate having an alkyl group having 4 to 8 carbon atoms (hereinafter " (also referred to as "C4-C8 alkyl acrylates").
　Ｃ１－Ｃ３アルキルアクリレートとしては、例えば、メチルアクリレート、エチルアクリレート、及びｎ－プロピルアクリレートが挙げられる。Ｃ１－Ｃ３アルキルアクリレートは、アクリルゴムの引張強度を向上させる観点から、好ましくは、メチルアクリレート及びエチルアクリレートからなる群より選ばれる少なくとも一種、より好ましくはエチルアクリレートを含む。 Examples of C1-C3 alkyl acrylates include methyl acrylate, ethyl acrylate, and n-propyl acrylate. From the viewpoint of improving the tensile strength of the acrylic rubber, the C1-C3 alkyl acrylate preferably contains at least one selected from the group consisting of methyl acrylate and ethyl acrylate, more preferably ethyl acrylate.
　Ｃ１－Ｃ３アルキルアクリレートの含有量は、モノマー全量を基準として、１０質量％以上、２０質量％以上、３０質量％以上、４０質量％以上、５０質量％以上、６０質量％以上、又は７０質量％以上であってよく、９５質量％以下、９０質量％以下、又は８０質量％以下であってよい。 The content of C1-C3 alkyl acrylate is 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass, based on the total amount of monomers. or more, and may be 95% by mass or less, 90% by mass or less, or 80% by mass or less.
　Ｃ４－Ｃ８アルキルアクリレートとしては、例えば、ｎ－ブチルアクリレート、イソブチルアクリレート、ｎ－ペンチルアクリレート、イソアミルアクリレート、ｎ－ヘキシルアクリレート、２－メチルペンチルアクリレート、ｎ－オクチルアクリレート、及び２－エチルヘキシルアクリレートが挙げられる。アルキルアクリレートは、アクリルゴムの耐寒性を向上させる観点から、好ましくはブチルアクリレート、更に好ましくはｎ－ブチルアクリレートを含む。 C4-C8 alkyl acrylates include, for example, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-methylpentyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. . The alkyl acrylate preferably contains butyl acrylate, more preferably n-butyl acrylate, from the viewpoint of improving the cold resistance of the acrylic rubber.
　Ｃ４－Ｃ８アルキルアクリレートの含有量は、モノマー全量を基準として、５質量％以上、１０質量％以上、又は２０質量％以上であってよく、８０質量％以下、７０質量％以下、又は６０質量％以下であってよい。 The content of C4-C8 alkyl acrylate, based on the total amount of monomers, may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 80% by mass or less, 70% by mass or less, or 60% by mass. may be:
　アルキルアクリレートは、好ましくは、Ｃ１－Ｃ３アルキルアクリレートからなる群より選ばれる少なくとも一種と、Ｃ４－Ｃ８アルキルアクリレートからなる群より選ばれる少なくとも一種とを含み、より好ましくは、メチルアクリレート又はエチルアクリレートと、ｎ－ブチルアクリレートとを含み、更に好ましくは、エチルアクリレートとｎ－ブチルアクリレートとを含む。 Alkyl acrylates preferably include at least one selected from the group consisting of C1-C3 alkyl acrylates and at least one selected from the group consisting of C4-C8 alkyl acrylates, more preferably methyl acrylate or ethyl acrylate, n-butyl acrylate, more preferably ethyl acrylate and n-butyl acrylate.
　モノマーは、アルキルアクリレートと共重合可能なその他のモノマーを更に含んでもよい。その他のモノマーは、例えばアルキルメタクリレートであってよい。アルキルメタクリレートは、例えば、炭素数１～１２のアルキル基を有するアルキルメタクリレートの一種又は二種以上を含む。当該アルキル基は、直鎖状であっても分岐状であってもよい。アルキルメタクリレートは、好ましくは炭素数１～８のアルキル基、より好ましくは炭素数１～４のアルキル基を有するアルキルメタクリレートを含む。 The monomer may further contain other monomers copolymerizable with the alkyl acrylate. Other monomers may be alkyl methacrylates, for example. Alkyl methacrylates include, for example, one or more alkyl methacrylates having an alkyl group of 1 to 12 carbon atoms. The alkyl group may be linear or branched. Alkyl methacrylates preferably include alkyl methacrylates having alkyl groups of 1 to 8 carbon atoms, more preferably alkyl groups of 1 to 4 carbon atoms.
　アルキルメタクリレートとしては、例えば、メチルメタクリレート、エチルメタクリレート、ｎ－プロピルメタクリレート、ｎ－ブチルメタクリレート、イソブチルメタクリレート、ｎ－ペンチルメタクリレート、ｎ－ヘキシルメタクリレート、ｎ－オクチルメタクリレート、２－エチルヘキシルメタクリレート、ｎ－デシルメタクリレート、及びｎ－ドデシルメタクリレートが挙げられる。 Examples of alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and n-decyl methacrylate. , and n-dodecyl methacrylate.
　アルキルメタクリレートは、好ましくは、メチルメタクリレート、エチルメタクリレート、ｎ－ブチルメタクリレート、ｎ－デシルメタクリレート、及びｎ－ドデシルメタクリレートからなる群より選ばれる少なくとも一種を含み、より好ましくは、メチルメタクリレート、エチルメタクリレート、及びｎ－ブチルメタクリレートからなる群より選ばれる少なくとも一種を含み、更に好ましくはｎ－ブチルメタクリレートを含む。 Alkyl methacrylate preferably contains at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate, more preferably methyl methacrylate, ethyl methacrylate, and It contains at least one selected from the group consisting of n-butyl methacrylate, more preferably n-butyl methacrylate.
　アルキルメタクリレートの含有量は、モノマー全量を基準として、５質量％以上、１０質量％以上、又は２０質量％以上であってよく、５０質量％以下、４０質量％以下、又は３０質量％以下であってよい。 The content of alkyl methacrylate may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total amount of monomers. you can
　その他のモノマーは、例えば酢酸ビニルであってよい。酢酸ビニルの含有量は、モノマー全量を基準として、５質量％以上、１０質量％以上、又は２０質量％以上であってよく、５０質量％以下、４０質量％以下、又は３０質量％以下であってよい。 The other monomer may be, for example, vinyl acetate. The content of vinyl acetate may be 5% by mass or more, 10% by mass or more, or 20% by mass or more, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total amount of monomers. you can
　その他のモノマーは、例えば架橋席モノマーであってよい。架橋席モノマーは、アルキルアクリレートと共重合可能であり、かつ架橋席（架橋点ともいう）を形成する官能基を有するモノマーである。架橋席モノマーは、重合性の炭素－炭素二重結合を有しており、例えば、アクリロイル基、メタクリロイル基、アリル基、メタアリル基、ビニル基、又はアルケニレン基を有している。 The other monomer may be, for example, a cross-linking monomer. A cross-linking site monomer is a monomer that is copolymerizable with an alkyl acrylate and has a functional group that forms a cross-linking site (also referred to as a cross-linking point). Cross-linking monomers have polymerizable carbon-carbon double bonds, such as acryloyl, methacryloyl, allyl, methallyl, vinyl, or alkenylene groups.
　上記官能基としては、例えば、エポキシ基、カルボキシル基及び活性塩素基が挙げられる。架橋席モノマーは、これらの官能基の一種又は二種以上を有していてよい。架橋席モノマーは、凝固工程における混合物中のアクリルポリマーの含有量を所定の範囲とすることによる、アクリルゴムの架橋物の圧縮永久ひずみの低減効果（詳細は後述する）が特に好適に得られる観点から、好ましくはカルボキシル基を有する架橋席モノマーである。 Examples of the functional groups include epoxy groups, carboxyl groups, and active chlorine groups. The cross-linking monomer may have one or more of these functional groups. The cross-linking site monomer is from the viewpoint that the effect of reducing the compression set of the cross-linked acrylic rubber (details will be described later) can be particularly preferably obtained by setting the content of the acrylic polymer in the mixture in the coagulation step to a predetermined range. Therefore, it is preferably a crosslinking site monomer having a carboxyl group.
　エポキシ基を有する架橋席モノマーは、好ましくはグリシジル基を有している。エポキシ基を有する架橋席モノマーとしては、例えば、グリシジルアクリレート、グリシジルメタクリレート、アリルグリシジルエーテル、及びメタアリルグリシジルエーテルが挙げられる。 The cross-linking monomer having an epoxy group preferably has a glycidyl group. Cross-linkable monomers having epoxy groups include, for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methallyl glycidyl ether.
　カルボキシル基を有する架橋席モノマー中のカルボキシル基の数は、１つであってよく、２つであってよく、３つ以上であってもよい。カルボキシル基を有する架橋席モノマーとしては、例えば、アクリル酸、メタクリル酸、クロトン酸、２－ペンテン酸、マレイン酸、フマル酸、イタコン酸、及びマレイン酸モノアルキルエステルが挙げられる。 The number of carboxyl groups in the crosslinking site monomer having a carboxyl group may be one, two, or three or more. Examples of crosslinking monomers having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid, itaconic acid, and maleic acid monoalkyl esters.
　活性塩素基を有する架橋席モノマーとしては、例えば、２－クロロエチルビニルエーテル、２－クロロエチルアクリレート、ビニルベンジルクロライド、クロロ酢酸ビニル、及びクロロ酢酸アリルが挙げられる。 Examples of cross-linkable monomers having active chlorine groups include 2-chloroethyl vinyl ether, 2-chloroethyl acrylate, vinylbenzyl chloride, vinyl chloroacetate, and allyl chloroacetate.
　架橋席モノマーの含有量は、架橋席モノマー以外のモノマー全量１００質量部に対して、０．５質量部以上、０．８質量部以上、１質量部以上、２質量部以上、又は３質量部以上であってよく、１０質量部以下、７質量部以下、又は５質量部以下であってよい。 The content of the crosslinking site monomer is 0.5 parts by mass or more, 0.8 parts by mass or more, 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass with respect to 100 parts by mass of the total amount of monomers other than the crosslinking site monomer. or more, and may be 10 parts by mass or less, 7 parts by mass or less, or 5 parts by mass or less.
　その他のモノマーは、例えば、エチレン、アルコキシアルキル（メタ）アクリレート、フッ素含有（メタ）アクリレート、水酸基含有（メタ）アクリレート、第３級アミノ基含有（メタ）アクリレート、アルキルビニルケトン、ビニルエーテル、アリルエーテル、芳香族ビニル化合物、ビニルニトリル、ハロゲン化ビニル、ハロゲン化ビニリデン等であってもよい。これらのその他のモノマーの含有量は、モノマー全量を基準として、１質量％以上であってよく、１０質量％以下であってよい。 Other monomers include, for example, ethylene, alkoxyalkyl (meth)acrylates, fluorine-containing (meth)acrylates, hydroxyl group-containing (meth)acrylates, tertiary amino group-containing (meth)acrylates, alkyl vinyl ketones, vinyl ethers, allyl ethers, It may be an aromatic vinyl compound, vinyl nitrile, vinyl halide, vinylidene halide, or the like. The content of these other monomers may be 1% by mass or more and 10% by mass or less based on the total amount of monomers.
　乳化剤は、上記の乳化重合に用いられる公知の乳化剤であってよい。乳化剤は、例えばノニオン系乳化剤であってよい。ノニオン系乳化剤は、エーテル型ノニオン系乳化剤、エステル型ノニオン系乳化剤、エーテルエステル型ノニオン系乳化剤、含窒素型ノニオン系乳化剤、及びポリビニルアルコール系乳化剤からなる群より選ばれる少なくとも一種を含んでよい。 The emulsifier may be a known emulsifier used in the above emulsion polymerization. The emulsifier may be, for example, a nonionic emulsifier. The nonionic emulsifier may contain at least one selected from the group consisting of an ether nonionic emulsifier, an ester nonionic emulsifier, an ether ester nonionic emulsifier, a nitrogen-containing nonionic emulsifier, and a polyvinyl alcohol emulsifier.
　エーテル型ノニオン系乳化剤としては、例えば、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルアリルエーテル、ポリオキシアルキレンアルキルエーテル、ポリオキシエチレンアルケニルエーテル、ポリオキシエチレンアルキルフェノールエーテル、ポリオキシエチレンポリオキシプロピレン共重合体、ポリオキシエチレンラウリルグリコール、及びポリオキシプロピレングリコールが挙げられる。 Examples of ether-type nonionic emulsifiers include polyoxyethylene alkyl ethers, polyoxyethylene alkylallyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene alkylphenol ethers, and polyoxyethylene polyoxypropylene copolymers. , polyoxyethylene lauryl glycol, and polyoxypropylene glycol.
　エステル型ノニオン系乳化剤としては、例えば、ソルビタン脂肪酸エステル、及びグリセリン脂肪酸エステルが挙げられる。ソルビタン脂肪酸エステルは、例えばモノエステルであってよい。グリセリン脂肪酸エステルは、例えば、モノエステルであってよく、ジエステルであってもよい。 Examples of ester-type nonionic emulsifiers include sorbitan fatty acid esters and glycerin fatty acid esters. Sorbitan fatty acid esters may be, for example, monoesters. Glycerin fatty acid esters may be, for example, monoesters or diesters.
　エーテルエステル型ノニオン系乳化剤としては、例えば、ポリオキシエチレン脂肪酸エステル、及びポリオキシエチレンソルビタン脂肪酸エステルが挙げられる。ポリオキシエチレン脂肪酸エステルは、例えば、モノエステルであってよく、ジエステルであってもよい。ポリオキシエチレンソルビタン脂肪酸エステルは、例えば、モノエステルであってよい。 Examples of ether ester-type nonionic emulsifiers include polyoxyethylene fatty acid esters and polyoxyethylene sorbitan fatty acid esters. Polyoxyethylene fatty acid esters may be, for example, monoesters or diesters. Polyoxyethylene sorbitan fatty acid esters can be, for example, monoesters.
　含窒素型ノニオン系乳化剤としては、例えば、ポリオキシエチレンアルキルアミン、ポリオキシエチレン脂肪酸モノエタノールアミド、及び脂肪酸ジエタノールアミドが挙げられる。 Examples of nitrogen-containing nonionic emulsifiers include polyoxyethylene alkylamines, polyoxyethylene fatty acid monoethanolamides, and fatty acid diethanolamides.
　ポリビニルアルコール系乳化剤は、完全けん化ポリビニルアルコールであってよく、部分けん化ポリビニルアルコールであってもよく、好ましくは部分けん化ポリビニルアルコールである。ポリビニルアルコールのけん化度は、好ましくは６０モル％以上、より好ましくは７０モル％以上、更に好ましくは８０モル％以上であり、好ましくは１００モル％以下、より好ましくは９９モル％以下、更に好ましくは９０モル％以下である。ポリビニルアルコールのけん化度は、ＪＩＳ　Ｋ６７２６「３．５　けん化度」に従って測定される値を意味する。 The polyvinyl alcohol-based emulsifier may be fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol, preferably partially saponified polyvinyl alcohol. The degree of saponification of polyvinyl alcohol is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, preferably 100 mol% or less, more preferably 99 mol% or less, still more preferably It is 90 mol % or less. The saponification degree of polyvinyl alcohol means a value measured according to JIS K6726 "3.5 saponification degree".
　乳化剤の添加量は、モノマー全量１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 The amount of the emulsifier added may be, for example, 0.1 parts by mass or more and may be 10 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
　重合開始剤は、例えば、アゾビスイソブチロニトリルなどのアゾ化合物、ｔｅｒｔ－ブチルヒドロペルオキシド、クメンハイドロパーオキサイド、ベンゾイルパーオキサイドなどの有機過酸化物、又は、過硫酸ナトリウム、過硫酸アンモニウムなどの無機過酸化物であってよく、好ましくはｔｅｒｔ－ブチルヒドロペルオキシドである。重合開始剤の添加量は、モノマー全量１００質量部に対して、例えば、０．０１質量部以上であってよく、２質量部以下であってよい。 The polymerization initiator is, for example, an azo compound such as azobisisobutyronitrile, an organic peroxide such as tert-butyl hydroperoxide, cumene hydroperoxide, or benzoyl peroxide, or an inorganic peroxide such as sodium persulfate or ammonium persulfate. It may be a peroxide, preferably tert-butyl hydroperoxide. The amount of the polymerization initiator added may be, for example, 0.01 parts by mass or more and may be 2 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
　懸濁液には、ｐＨ調整剤を更に添加してもよい。ｐＨ調整剤は、例えば、酢酸ナトリウム、水酸化ナトリウム、水酸化カリウム、リン酸ナトリウム、クエン酸ナトリウムなどのアルカリ金属塩であってよく、好ましくは酢酸ナトリウムである。ｐＨ調整剤の添加量は、モノマー全量１００質量部に対して、例えば、０．１質量部以上であってよく、５質量部以下であってよい。 A pH adjuster may be added to the suspension. The pH adjuster may be, for example, an alkali metal salt such as sodium acetate, sodium hydroxide, potassium hydroxide, sodium phosphate, sodium citrate, preferably sodium acetate. The amount of the pH adjuster added may be, for example, 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total amount of the monomers.
　重合工程に続く凝固工程及びそれ以降の工程は、例えば押出機を用いて実施される。図１は、当該押出機の一例を示す模式図である。一実施形態において、押出機１は、凝固ゾーン２と、第一の排水ゾーン３と、第一の洗浄ゾーン４と、第二の排水ゾーン５と、第二の洗浄ゾーン６と、第三の排水ゾーン７と、乾燥ゾーン８とをこの順に備えている。 The coagulation process following the polymerization process and subsequent processes are carried out using, for example, an extruder. FIG. 1 is a schematic diagram showing an example of the extruder. In one embodiment, the extruder 1 comprises a coagulation zone 2, a first drainage zone 3, a first washing zone 4, a second drainage zone 5, a second washing zone 6 and a third A drainage zone 7 and a drying zone 8 are provided in this order.
　凝固工程では、凝固ゾーン２に、アクリルポリマー及び乳化剤を含有するラテックスＬと、凝固剤を含有する凝固液Ｃとをそれぞれ供給し、ラテックスＬ及び凝固液Ｃを混合することにより、アクリルポリマーを凝固させる。 In the coagulation step, a latex L containing an acrylic polymer and an emulsifier and a coagulating liquid C containing a coagulant are respectively supplied to the coagulating zone 2, and the latex L and the coagulating liquid C are mixed to coagulate the acrylic polymer. Let
　凝固液Ｃは、例えば、凝固剤を含有する水溶液であってよく、凝固剤及び水のみからなる水溶液であってよい。凝固液Ｃ中の凝固剤の含有量は、アクリルポリマーの量に応じて適切な量の凝固剤が添加されるように設定される。例えば、凝固液の添加量は、アクリルポリマー１００質量部に対して、１質量部以上、３質量部以上、又は５質量部以上であってよく、５０質量部以下、４０質量部以下、又は３０質量部以下であってよい。凝固液Ｃ中の凝固剤の含有量は、このような添加量となるように設定されればよく、例えば、凝固液Ｃ全量を基準として、１質量％以上、２質量％以上、３質量％以上、４質量％以上、又は５質量％以上であってよく、１０質量％以下、９質量％以下、８質量％以下、７質量％以下、６質量％以下、又は５質量％以下であってよい。 The coagulating liquid C may be, for example, an aqueous solution containing a coagulant, or an aqueous solution consisting only of a coagulant and water. The content of the coagulant in the coagulant liquid C is set so that an appropriate amount of coagulant is added according to the amount of the acrylic polymer. For example, the amount of the coagulating liquid added may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more relative to 100 parts by mass of the acrylic polymer, and may be 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass. It may be less than or equal to parts by mass. The content of the coagulant in the coagulating liquid C may be set so as to be such an amount to be added. Above, 4% by mass or more, or 5% by mass or more, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less good.
　凝固剤としては、例えば、アンモニウム塩、１～３価の金属塩、無機酸、及び有機酸が挙げられる。アンモニウム塩としては、例えば、ホウ酸アンモニウム、硫酸アンモニウム、及び塩化アンモニウムが挙げられる。１～３価の金属塩としては、例えば、ナトリウム塩、マグネシウム塩、カルシウム塩、アルミニウム塩、及び亜鉛塩が挙げられる。ナトリウム塩としては、例えば、ホウ酸ナトリウム、硫酸ナトリウム、及び塩化ナトリウムが挙げられる。マグネシウム塩としては、例えば、硫酸マグネシウム、塩化マグネシウム、及び硝酸マグネシウムが挙げられる。カルシウム塩としては、例えば、硫酸カルシウム、塩化カルシウム、及び硝酸カルシウムが挙げられる。アルミニウム塩としては、例えば、硫酸アルミニウム及び塩化アルミニウムが挙げられる。亜鉛塩としては、例えば、塩化亜鉛及び酢酸亜鉛が挙げられる。無機酸としては、例えば、塩酸、硫酸、及び硝酸が挙げられる。有機酸としては、例えば、蟻酸及び酢酸が挙げられる。 Coagulants include, for example, ammonium salts, monovalent to trivalent metal salts, inorganic acids, and organic acids. Ammonium salts include, for example, ammonium borate, ammonium sulfate, and ammonium chloride. Examples of monovalent to trivalent metal salts include sodium salts, magnesium salts, calcium salts, aluminum salts, and zinc salts. Sodium salts include, for example, sodium borate, sodium sulfate, and sodium chloride. Magnesium salts include, for example, magnesium sulfate, magnesium chloride, and magnesium nitrate. Calcium salts include, for example, calcium sulfate, calcium chloride, and calcium nitrate. Aluminum salts include, for example, aluminum sulfate and aluminum chloride. Zinc salts include, for example, zinc chloride and zinc acetate. Inorganic acids include, for example, hydrochloric acid, sulfuric acid, and nitric acid. Organic acids include, for example, formic acid and acetic acid.
　凝固工程では、ラテックスＬと凝固液Ｃとの混合物中のアクリルポリマーの含有量が、混合物全量を基準として２０質量％以下となるように、ラテックスＬ及び凝固液Ｃを凝固ゾーン２に供給する。これにより、得られるアクリルゴムの架橋物の圧縮永久ひずみを小さくすることができる。このような効果が得られる理由は、アクリルポリマーの含有量が少ないことにより、アクリルポリマーと共存する乳化剤を後述する洗浄工程において除去しやすくなるためであると推測される。当該混合物中のアクリルポリマーの含有量は、アクリルゴムの架橋物の圧縮永久ひずみを更に小さくすることができる観点から、混合物全量を基準として、好ましくは、１９質量％以下、１７質量％以下、１５質量％以下、１４質量％以下、１３質量％以下、１２質量％以下、１１質量％以下、又は１０質量％以下であってもよい。当該混合物中のアクリルポリマーの含有量は、混合物全量を基準として、５質量％以上、６質量％以上、７質量％以上、８質量％以上、９質量％以上、又は１０質量％以上であってもよい。 In the coagulation step, the latex L and the coagulation liquid C are supplied to the coagulation zone 2 so that the content of the acrylic polymer in the mixture of the latex L and the coagulation liquid C is 20% by mass or less based on the total amount of the mixture. Thereby, the compression set of the obtained crosslinked acrylic rubber can be reduced. It is speculated that the reason why such an effect is obtained is that the emulsifier coexisting with the acrylic polymer can be easily removed in the washing step described below due to the small content of the acrylic polymer. The content of the acrylic polymer in the mixture is preferably 19% by mass or less, 17% by mass or less, 15% by mass or less, based on the total amount of the mixture, from the viewpoint that the compression set of the crosslinked acrylic rubber can be further reduced. % by mass or less, 14% by mass or less, 13% by mass or less, 12% by mass or less, 11% by mass or less, or 10% by mass or less. The content of the acrylic polymer in the mixture is 5% by mass or more, 6% by mass or more, 7% by mass or more, 8% by mass or more, 9% by mass or more, or 10% by mass or more, based on the total amount of the mixture. good too.
　混合物中のアクリルポリマーの含有量は、ラテックスＬ中のアクリルポリマーの含有量と、混合物中のラテックスＬ及び凝固液Ｃの混合比（言い換えれば、ラテックスＬ及び凝固液Ｃの供給量）とを調整することにより、上記の範囲内にすることができる。 The content of the acrylic polymer in the mixture is adjusted by adjusting the content of the acrylic polymer in the latex L and the mixing ratio of the latex L and the coagulating liquid C in the mixture (in other words, the amount of the latex L and the coagulating liquid C supplied). By doing so, it is possible to make it within the above range.
　ラテックスＬは、重合工程で得られた反応物（アクリルポリマーと乳化剤とを含有する）をそのまま用いてもよく、当該反応物を例えば水で希釈してラテックスＬ中のアクリルポリマーの含有量を調整した上で用いてもよい。 For the latex L, the reaction product (containing the acrylic polymer and the emulsifier) obtained in the polymerization step may be used as it is, and the content of the acrylic polymer in the latex L may be adjusted by diluting the reaction product with water, for example. It may be used after
　ラテックスＬ中のアクリルポリマーの含有量は、一実施形態において、ラテックスＬ全量を基準として、３０質量％以上、３１質量％以上、３２質量％以上、３３質量％以上、３４質量％以上、又は３５質量％以上であってよく、５０質量％以下であってよい。この場合、混合物中のアクリルポリマーの含有量を上記の範囲とするために、混合物中のラテックスＬの含有量に対する凝固液Ｃの含有量の質量比（凝固液Ｃの供給量／ラテックスＬの供給量）は、好ましくは、０．６以上、０．７以上、０．８以上、０．９以上、１以上、１．５以上、１．８以上、２以上、又は２．２以上であり、例えば４以下であってよい。この場合、アクリルゴムの架橋物の圧縮永久ひずみを小さくできることに加えて、アクリルゴムの収率を高くできる。 In one embodiment, the content of the acrylic polymer in the latex L is 30% by mass or more, 31% by mass or more, 32% by mass or more, 33% by mass or more, 34% by mass or more, or 35% by mass or more, based on the total amount of the latex L. It may be at least 50% by mass, and may be at most 50% by mass. In this case, in order to make the content of the acrylic polymer in the mixture within the above range, the mass ratio of the content of the coagulating liquid C to the content of the latex L in the mixture (supply amount of coagulating liquid C/supply of latex L amount) is preferably 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.5 or more, 1.8 or more, 2 or more, or 2.2 or more , for example 4 or less. In this case, the compression set of the crosslinked acrylic rubber can be reduced, and the yield of the acrylic rubber can be increased.
　ラテックスＬ中のアクリルポリマーの含有量は、他の一実施形態において、ラテックスＬ全量を基準として、３０質量％未満、２５質量％以下、２０質量％以下、１７質量％以下、又は１５質量％以下であってよく、例えば１０質量％以上であってよい。この場合、ラテックスＬ中のアクリルポリマーの含有量が比較的少ないため、混合物中のアクリルポリマーの含有量を上記の範囲に調整しやすい。混合物中のラテックスＬの含有量に対する凝固液Ｃの含有量の質量比（凝固液Ｃの供給量／ラテックスＬの供給量）は、例えば、０．１以上、０．２以上、０．３以上、０．４以上、又は０．５以上であってよく、１以下、０．９以下、０．８以下、０．７以下、０．６以下、又は０．５以下であってよい。この実施形態では、アクリルゴムの架橋物の圧縮永久ひずみを更に小さくすることができる。 In another embodiment, the content of the acrylic polymer in the latex L is less than 30% by mass, 25% by mass or less, 20% by mass or less, 17% by mass or less, or 15% by mass or less based on the total amount of the latex L. For example, it may be 10% by mass or more. In this case, since the content of the acrylic polymer in the latex L is relatively small, it is easy to adjust the content of the acrylic polymer in the mixture within the above range. The mass ratio of the content of the coagulating liquid C to the content of the latex L in the mixture (the amount of the coagulating liquid C supplied/the amount of the latex L supplied) is, for example, 0.1 or more, 0.2 or more, or 0.3 or more. , 0.4 or more, or 0.5 or more, and may be 1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less. In this embodiment, the compression set of the crosslinked acrylic rubber can be further reduced.
　アクリルゴムの製造方法は、凝固工程に続いて、第一の排水工程と、第一の洗浄工程と、第二の排水工程と、第二の洗浄工程と、第三の排水工程と、乾燥工程とをこの順に更に備えていてもよい。これらの各工程は、押出機１のスクリューを回転させることによって、凝固ゾーン２で凝固させたアクリルポリマーを押し出しながら実施される。押出機１のスクリューの回転数は、例えば、４０ｒｐｍ以上であってよく、２００ｒｐｍ以下であってよい。 The method for producing acrylic rubber comprises a coagulation step followed by a first drainage step, a first washing step, a second drainage step, a second washing step, a third drainage step, and a drying step. and may be further provided in this order. Each of these steps is carried out while extruding the acrylic polymer solidified in the solidification zone 2 by rotating the screw of the extruder 1 . The screw rotation speed of the extruder 1 may be, for example, 40 rpm or more and may be 200 rpm or less.
　第一の排水工程では、第一の排水ゾーン３において、押出機１のスクリューの回転によって、凝固したアクリルポリマーの脱水を行うと共に、排水スリットから排水Ｄ１を行う。 In the first drainage process, in the first drainage zone 3, the screw of the extruder 1 is rotated to dehydrate the solidified acrylic polymer, and the drainage D1 is performed from the drainage slit.
　第一の洗浄工程では、第一の洗浄ゾーン４において、洗浄液Ｗ１を供給しながら押出機１のスクリューを回転させることによって、凝固したアクリルポリマーを洗浄し、凝固したアクリルポリマー中の不純物（乳化剤、凝固剤、未反応物など）を除去する。洗浄液Ｗ１は、例えば水であってよい。 In the first washing step, in the first washing zone 4, by rotating the screw of the extruder 1 while supplying the washing liquid W1, the solidified acrylic polymer is washed to remove impurities (emulsifier, coagulants, unreacted substances, etc.) are removed. The cleaning liquid W1 may be water, for example.
　第二の排水工程では、第二の排水ゾーン５において、押出機１のスクリューの回転によって、凝固したアクリルポリマーの脱水を行うと共に、排水スリットから排水Ｄ２を行う。 In the second drainage process, in the second drainage zone 5, the screw of the extruder 1 is rotated to dewater the solidified acrylic polymer, and the drainage D2 is performed from the drainage slit.
　第二の洗浄工程では、第二の洗浄ゾーン６において、洗浄液Ｗ２を供給しながら押出機１のスクリューを回転させることによって、凝固したアクリルポリマーを更に洗浄し、凝固したアクリルポリマー中の不純物（乳化剤、凝固剤、未反応物など）を更に除去する。洗浄液Ｗ２は、例えば水であってよい。 In the second washing step, in the second washing zone 6, the screw of the extruder 1 is rotated while supplying the washing liquid W2 to further wash the solidified acrylic polymer to remove impurities (emulsifiers) in the solidified acrylic polymer. , coagulants, unreacted substances, etc.) are further removed. The cleaning liquid W2 may be water, for example.
　第三の排水工程では、第三の排水ゾーン７において、押出機１のスクリューの回転によって、凝固したアクリルポリマーの脱水を行うと共に、排水スリットから排水Ｄ３を行う。 In the third drainage process, in the third drainage zone 7, the screw of the extruder 1 is rotated to dewater the solidified acrylic polymer, and the drainage D3 is performed from the drainage slit.
　第一の洗浄工程及び第二の洗浄工程で供給される洗浄液Ｗ１，Ｗ２の合計量は、アクリルポリマー１００質量部に対して、例えば、２５０質量部以上であってよく、８００質量部以下であってよい。 The total amount of the cleaning liquids W1 and W2 supplied in the first cleaning step and the second cleaning step may be, for example, 250 parts by mass or more and 800 parts by mass or less with respect to 100 parts by mass of the acrylic polymer. you can
　乾燥工程では、乾燥ゾーン８において、例えば減圧条件下で加熱することにより、凝固したアクリルポリマーを乾燥させる。減圧条件の圧力は、例えば、９０ｋＰａ以下であってよく、５０ｋＰａ以上であってよい。加熱は、例えば、乾燥ゾーン８の温度を高くすると共に、押出機１のヘッドを高くすることにより行われる。乾燥ゾーン８の温度は、例えば、１０５℃以上であってよく、２００℃以下であってよい。押出機１のヘッドの温度は、例えば、１３０℃以上であってよく、２００℃以下であってよい。 In the drying process, the solidified acrylic polymer is dried in the drying zone 8 by, for example, heating under reduced pressure conditions. The pressure of the decompression condition may be, for example, 90 kPa or less and may be 50 kPa or more. Heating is performed, for example, by raising the temperature of the drying zone 8 and raising the head of the extruder 1 . The temperature of the drying zone 8 may be, for example, 105° C. or higher and 200° C. or lower. The temperature of the head of the extruder 1 may be, for example, 130° C. or higher and 200° C. or lower.
　以上の工程を経て、押出機１からアクリルゴムＲが押し出され、アクリルゴムＲが得られる。このようにして得られるアクリルゴムは、必要に応じて添加剤と混合してゴム組成物として用いられてよい。本発明の他の一実施形態は、上記のアクリルゴムの製造方法によりアクリルゴムを得る工程と、当該アクリルゴムと添加剤とを混合してゴム組成物を得る工程と、を備えるゴム組成物の製造方法である。 Through the above steps, the acrylic rubber R is extruded from the extruder 1 to obtain the acrylic rubber R. The acrylic rubber thus obtained may be used as a rubber composition by mixing with additives as necessary. Another embodiment of the present invention is a rubber composition comprising a step of obtaining an acrylic rubber by the above-described method for producing an acrylic rubber, and a step of mixing the acrylic rubber and an additive to obtain a rubber composition. manufacturing method.
　アクリルゴムの含有量は、ゴム組成物の全量を基準として、例えば、５０質量％以上、５５質量％以上、又は６０質量％以上であってよく、９０質量％以下であってよい。 The content of the acrylic rubber may be, for example, 50% by mass or more, 55% by mass or more, or 60% by mass or more, and may be 90% by mass or less based on the total amount of the rubber composition.
　添加剤としては、例えば、充填剤、滑剤、老化防止剤、界面活性剤、架橋剤、及び架橋促進剤が挙げられる。 Additives include, for example, fillers, lubricants, antioxidants, surfactants, cross-linking agents, and cross-linking accelerators.
　充填剤としては、例えばカーボンブラック、シリカ、タルク及び炭酸カルシウムが挙げられる。充填剤の含有量は、アクリルゴム１００質量部に対して、例えば、３０質量部以上であってよく、１００質量部以下であってよい。 Fillers include, for example, carbon black, silica, talc and calcium carbonate. The content of the filler may be, for example, 30 parts by mass or more and may be 100 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　滑剤としては、例えば、流動パラフィン、ステアリン酸、ステアリルアミン、脂肪酸亜鉛、脂肪酸エステル、及びオルガノシリコーンが挙げられる。滑剤の含有量は、アクリルゴム１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 Lubricants include, for example, liquid paraffin, stearic acid, stearylamine, fatty acid zinc, fatty acid esters, and organosilicones. The content of the lubricant may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　老化防止剤としては、例えば芳香族アミン化合物及びフェノール化合物が挙げられる。老化防止剤の含有量は、アクリルゴム１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 Anti-aging agents include, for example, aromatic amine compounds and phenol compounds. The content of the anti-aging agent may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　界面活性剤としては、例えばアルキル硫酸エステル塩が挙げられる。界面活性剤の含有量は、アクリルゴム１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 Examples of surfactants include alkyl sulfate salts. The content of the surfactant may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　架橋剤としては、例えば、イミダゾール化合物及びジアミン化合物が挙げられる。架橋剤の含有量は、アクリルゴム１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 Examples of cross-linking agents include imidazole compounds and diamine compounds. The content of the cross-linking agent may be, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　架橋促進剤は、ゴム組成物が架橋剤を含有する場合に、好ましく用いられる。架橋促進剤としては、例えば、トリメチルチオ尿素化合物、フェノチアジン化合物、脂肪族１価２級アミン化合物、脂肪族１価３級アミン化合物、第四級オニウム塩、第三級ホスフィン化合物、弱酸のアルカリ金属塩、ジアザビシクロアルケン化合物及びグアニジン化合物が挙げられる。架橋促進剤の含有量は、アクリルゴム１００質量部に対して、例えば、０．１質量部以上であってよく、１０質量部以下であってよい。 A cross-linking accelerator is preferably used when the rubber composition contains a cross-linking agent. Examples of cross-linking accelerators include trimethylthiourea compounds, phenothiazine compounds, aliphatic monovalent secondary amine compounds, aliphatic monovalent tertiary amine compounds, quaternary onium salts, tertiary phosphine compounds, and weakly acidic alkali metals. Salts, diazabicycloalkene compounds and guanidine compounds are included. The content of the crosslinking accelerator may be, for example, 0.1 parts by mass or more and may be 10 parts by mass or less with respect to 100 parts by mass of the acrylic rubber.
　ゴム組成物は、架橋された状態で（架橋物として）好適に用いられる。本発明の他の一実施形態は、上記のアクリルゴムの製造方法によりアクリルゴムを得る工程と、当該アクリルゴムと添加剤とを混合してゴム組成物を得る工程と、当該ゴム組成物を架橋させて架橋物を得る工程と、を備えるゴム組成物の架橋物の製造方法である。 The rubber composition is preferably used in a crosslinked state (as a crosslinked product). Another embodiment of the present invention comprises steps of obtaining an acrylic rubber by the above-described method for producing an acrylic rubber, mixing the acrylic rubber and an additive to obtain a rubber composition, and cross-linking the rubber composition. and obtaining a crosslinked product of a rubber composition.
　ゴム組成物を架橋させる方法は、公知の方法であってよい。架橋物を得る工程は、例えば、ゴム組成物を加熱及び加圧する第一の架橋工程と、第一の架橋工程後のゴム組成物を更に加熱する第二の架橋工程とを備えていてよい。 The method for cross-linking the rubber composition may be a known method. The step of obtaining a crosslinked product may comprise, for example, a first crosslinking step of heating and pressurizing the rubber composition, and a second crosslinking step of further heating the rubber composition after the first crosslinking step.
　第一の架橋工程において、加熱温度は、例えば、１５０℃以上であってよく、２２０℃以下であってよい。加圧時の圧力は、例えば、０．４ＭＰａ以上であってよく、２０ＭＰａ以下であってよい。加熱及び加圧を行う時間は、例えば、５分間以上であってよく、２時間以下であってよい。 In the first cross-linking step, the heating temperature may be, for example, 150°C or higher and 220°C or lower. The pressure during pressurization may be, for example, 0.4 MPa or more and may be 20 MPa or less. The time for heating and pressurizing may be, for example, 5 minutes or more and 2 hours or less.
　第二の架橋工程において、加熱温度は、例えば、１５０℃以上であってよく、２２０℃以下であってよい。加熱時間は、例えば、３０分間以上であってよく、２４時間以下であってよい。 In the second cross-linking step, the heating temperature may be, for example, 150°C or higher and 220°C or lower. The heating time may be, for example, 30 minutes or longer and may be 24 hours or shorter.
　アクリルゴムを構成するモノマーが架橋席モノマーを含む場合、架橋席モノマーの架橋席（架橋点）により、アクリルゴム同士の架橋が形成される。この場合、ゴム組成物が架橋剤を含有していると、架橋剤によりアクリルゴム同士の架橋が更に形成される。あるいは、アクリルゴムを構成するモノマーが架橋席モノマーを含まず、ゴム組成物が架橋剤を含有する場合、架橋剤によりアクリルゴム同士の架橋が形成される。 When the monomer constituting the acrylic rubber contains a cross-linking site monomer, the cross-linking sites (cross-linking points) of the cross-linking site monomer form cross-links between the acrylic rubbers. In this case, if the rubber composition contains a cross-linking agent, cross-linking between the acrylic rubbers is further formed by the cross-linking agent. Alternatively, when the monomer constituting the acrylic rubber does not contain a cross-linking site monomer and the rubber composition contains a cross-linking agent, cross-linking between the acrylic rubbers is formed by the cross-linking agent.
　ゴム組成物の架橋物は、特に、ゴムホースや、ガスケット、パッキング等のシール部品として好適に用いられる。ゴムホースとしては、例えば、自動車、建設機械、油圧機器等のトランスミッションオイルクーラーホース、エンジンオイルクーラーホース、エアダクトホース、ターボホース、ホットエアーホース、ラジエターホース、パワーステアリングホース、燃料系統用ホース、及びドレイン系統用ホース等が挙げられる。上記の製造方法により得られるアクリルゴムを含有するゴム組成物の架橋物は、圧縮永久ひずみの点で優れているため、ターボホース及びシール部品として特に好適である。 A crosslinked product of a rubber composition is particularly suitable for use as sealing parts such as rubber hoses, gaskets, and packings. Examples of rubber hoses include transmission oil cooler hoses for automobiles, construction machinery, hydraulic equipment, engine oil cooler hoses, air duct hoses, turbo hoses, hot air hoses, radiator hoses, power steering hoses, fuel system hoses, and drain systems. hoses, etc. The crosslinked product of the rubber composition containing acrylic rubber obtained by the above production method is particularly suitable for turbo hoses and sealing parts because it is excellent in terms of compression set.
　シール部品としては、例えば、エンジンヘッドカバーガスケット、オイルパンガスケット、オイルシール、リップシールパッキン、Ｏ－リング、トランスミッションシールガスケット、クランクシャフト、カムシャフトシールガスケット、バルブステム、パワーステアリングシールベルトカバーシール、等速ジョイント用ブーツ材及びラックアンドピニオンブーツ材が挙げられる。 Seal parts include, for example, engine head cover gaskets, oil pan gaskets, oil seals, lip seal packings, O-rings, transmission seal gaskets, crankshafts, camshaft seal gaskets, valve stems, power steering seal belt cover seals, constant velocity Boot materials for joints and rack and pinion boot materials are included.
　以下、実施例をよって本発明を更に具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.
＜実施例１－１～１－４及び比較例１－１＞
（アクリルゴムの製造）
　内容積４０リットルの耐圧反応容器に、エチルアクリレート７０質量部、ｎ－ブチルアクリレート３０質量部、及びマレイン酸モノブチル２．６６質量部からなるモノマー混合物１１ｋｇと、乳化剤として部分けん化ポリビニルアルコールの４質量％水溶液（ポリビニルアルコールのけん化度：８８モル％）１７ｋｇと、酢酸ナトリウム２２ｇとを投入し、攪拌機であらかじめよく混合し、均一懸濁液を作製した。容器内上部の空気を窒素で置換後、攪拌を続行し、容器内を５５℃に保持した後、ｔ－ブチルヒドロペルオキシド水溶液（０．２５質量％）２リットルを加えて、乳化重合を開始させた。容器内温度を５５℃に保ち、６時間後に反応を終了させた。 <Examples 1-1 to 1-4 and Comparative Example 1-1>
(Manufacture of acrylic rubber)
11 kg of a monomer mixture consisting of 70 parts by mass of ethyl acrylate, 30 parts by mass of n-butyl acrylate, and 2.66 parts by mass of monobutyl maleate, and 4% by mass of partially saponified polyvinyl alcohol as an emulsifier were placed in a pressure-resistant reaction vessel having an internal volume of 40 liters. 17 kg of an aqueous solution (degree of saponification of polyvinyl alcohol: 88 mol %) and 22 g of sodium acetate were added and thoroughly mixed in advance with a stirrer to prepare a uniform suspension. After replacing the air in the upper part of the container with nitrogen, stirring was continued, and after maintaining the inside of the container at 55° C., 2 liters of t-butyl hydroperoxide aqueous solution (0.25% by mass) was added to initiate emulsion polymerization. rice field. The temperature inside the container was kept at 55° C., and the reaction was terminated after 6 hours.
　反応終了後の反応液に対して、必要に応じて水を添加して、表１に示す量（ラテックス全量を基準とした質量％）のアクリルポリマーを含有する（更には上述した乳化剤等を含有する）ラテックスを得た。また、凝固剤として、ホウ酸ナトリウム１．２５質量部、硫酸アンモニウム２．２５質量部、及びホウ酸アンモニウム３．７５質量部の混合物を用い、この混合物（凝固剤）の含有量が表１に示す量（凝固液全量を基準とした質量％）となるように水に溶解して凝固液を得た。 Water is added as necessary to the reaction solution after the completion of the reaction to contain the acrylic polymer in the amount shown in Table 1 (% by mass based on the total amount of latex) (further containing the above-described emulsifier, etc.) do) got latex. As a coagulant, a mixture of 1.25 parts by mass of sodium borate, 2.25 parts by mass of ammonium sulfate, and 3.75 parts by mass of ammonium borate was used, and the content of this mixture (coagulant) is shown in Table 1. A solidified liquid was obtained by dissolving in water so that the amount (% by mass based on the total amount of the solidified liquid) was obtained.
　次に、図１に模式的に示すような構成（詳細は前述）を備える押出機１（二軸混練押出機、ＴＥＭ－５０、東芝機械社製）において、得られたラテックスＬ及び凝固液Ｃをそれぞれ表１に示す供給量で凝固ゾーン２に供給して混合し、アクリルポリマーを凝固させた。続いて、押出機１のスクリューの回転数：１２０ｒｐｍにて、凝固させたアクリルポリマーを押し出しながら、第一の排水ゾーン３において、アクリルポリマーから排水Ｄ１を行った。その後、洗浄液Ｗ１，Ｗ２として水を使用し、第一の洗浄ゾーン４における水洗及び第二の排水ゾーン５における排水Ｄ２と、第二の洗浄ゾーン６における水洗及び第三の排水ゾーン７における排水Ｄ３とを順次行った。第一の洗浄ゾーン４及び第二の洗浄ゾーン６で使用した水の合計量は、アクリルポリマー１００質量部に対して４３０質量部であった。最後に、乾燥ゾーン８において、減圧（８０ｋＰａ）下にてアクリルポリマーを加熱（乾燥ゾーン８の温度：１５０℃、押出機のヘッドの温度：１５５℃）することにより、アクリルゴムを得た。 Next, in an extruder 1 (twin-screw kneading extruder, TEM-50, manufactured by Toshiba Machine Co., Ltd.) equipped with the configuration schematically shown in FIG. were supplied to the coagulation zone 2 in the amounts shown in Table 1 and mixed to coagulate the acrylic polymer. Subsequently, while extruding the solidified acrylic polymer at a screw rotation speed of 120 rpm in the extruder 1 , the acrylic polymer was drained D1 in the first drainage zone 3 . After that, using water as the cleaning liquids W1 and W2, washing with water D2 in the first washing zone 4 and drainage D2 in the second drainage zone 5, washing with water in the second cleaning zone 6 and drainage D3 in the third drainage zone 7 and were performed sequentially. The total amount of water used in the first washing zone 4 and the second washing zone 6 was 430 parts by weight per 100 parts by weight of the acrylic polymer. Finally, in drying zone 8, acrylic rubber was obtained by heating the acrylic polymer under reduced pressure (80 kPa) (temperature in drying zone 8: 150°C, temperature of extruder head: 155°C).
　なお、表１に示すラテックスと凝固液との混合物中のアクリルポリマーの含有量（質量％）は、下記式により算出した。
　混合物中のアクリルポリマーの含有量＝ＦＡ／（ＦＬ＋ＦＣ）×１００
式中、
　ＦＡ：アクリルポリマーの供給量（ｋｇ／ｈ）
　ＦＬ：ラテックスの供給量（ｋｇ／ｈ）
　ＦＣ：凝固液の供給量（ｋｇ／ｈ）
であり、ＦＡは下記式により算出した。
　ＦＡ＝ＦＬ×ＣＡ／１００
式中、
　ＣＡ：ラテックス中のアクリルポリマーの含有量（質量％）
である。 The acrylic polymer content (% by mass) in the mixture of latex and coagulating liquid shown in Table 1 was calculated by the following formula.
Content of acrylic polymer in the mixture = F A /(F L +F C ) x 100
During the ceremony,
F A : Supply amount of acrylic polymer (kg/h)
F L : Amount of latex supplied (kg/h)
F C : Amount of coagulation liquid supplied (kg/h)
and F A was calculated by the following formula.
F A =F L ×C A /100
During the ceremony,
C A : Content of acrylic polymer in latex (% by mass)
is.
（ゴム組成物の調製）
　続いて、得られた各アクリルゴム１００質量部と以下の成分とを８インチオープンロールで混練することにより、ゴム組成物を得た。
　充填剤：カーボンブラック（東海カーボン社製　シーストＳＯ）５０質量部
　滑剤：ステアリン酸（花王社製　ルナックＳ－９０）１質量部、及びステアリルアミン（花王社製　ファーミン８０）０．３質量部
　老化防止剤：４，４’－ビス（α，α－ジメチルベンジル）ジフェニルアミン（アディバント社製　Ｎａｕｇａｒｄ＃４４５）１質量部
　架橋剤：６－アミノヘキシルカルバミド酸（デュポン社製　Ｄｉａｋ＃１）０．６質量部
　架橋促進剤：１，８－ジアザビシクロ－５，４，０－ウンデカ－７－エン含有物（ランクセス社製　ＲＨＥＮＯＧＲＡＮ　ＸＬＡ－６０）０．８質量部 (Preparation of rubber composition)
Subsequently, 100 parts by mass of each of the obtained acrylic rubbers and the following components were kneaded with an 8-inch open roll to obtain a rubber composition.
Filler: 50 parts by mass of carbon black (Sheast SO manufactured by Tokai Carbon Co., Ltd.) Lubricant: 1 part by mass of stearic acid (Lunac S-90 manufactured by Kao Corporation) and 0.3 parts by mass of stearylamine (Furmin 80 manufactured by Kao Corporation) Anti-aging Agent: 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (Naugard #445 manufactured by Addivant) 1 part by mass Cross-linking agent: 6-aminohexylcarbamic acid (Diak #1 manufactured by DuPont) 0.6 parts by mass Crosslinking accelerator: 1,8-diazabicyclo-5,4,0-undec-7-ene-containing material (RHENOGRAN XLA-60 manufactured by Lanxess) 0.8 parts by mass
（圧縮永久ひずみの評価）
　得られたゴム組成物を厚さ２．４ｍｍのシートに分出しした後、プレス加硫機を用いて、１７０℃、１０ＭＰａの条件で、上記シートを６枚重ねた状態で、２０分間加熱及び加圧することにより、一次加硫（架橋）を行った。その後、ギヤーオーブンを用いて、１７０℃で４時間加熱することにより、二次加硫（架橋）を行い、直径２９．０±０．５ｍｍ、厚さ１２．５±０．５ｍｍの円盤状の試験片を得た。当該試験片について、ＪＩＳ　Ｋ６２６２に準拠して、１５０℃、１４４時間における圧縮永久ひずみ（％）を測定した。表１には、比較例１－１の圧縮永久ひずみを１００としたときの各実施例の圧縮永久ひずみの相対値を示す。 (Evaluation of compression set)
After dispensing the obtained rubber composition into sheets with a thickness of 2.4 mm, using a press vulcanizer, under the conditions of 170 ° C. and 10 MPa, six of the above sheets are stacked and heated for 20 minutes. Primary vulcanization (crosslinking) was performed by applying pressure. After that, secondary vulcanization (crosslinking) was performed by heating at 170° C. for 4 hours using a gear oven, and a disk-shaped product with a diameter of 29.0±0.5 mm and a thickness of 12.5±0.5 mm was formed. A specimen was obtained. The test piece was measured for compression set (%) at 150° C. for 144 hours according to JIS K6262. Table 1 shows the relative value of the compression set of each example when the compression set of Comparative Example 1-1 is 100.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
＜実施例２－１～２－２及び比較例２－１＞
　アクリルゴムの製造において、モノマー混合物の組成を、エチルアクリレート８０質量部、ｎ－ブチルアクリレート２０質量部、及びマレイン酸モノブチル４．００質量部に変更した以外は、実施例１－１と同様にして、アクリルゴムの製造、ゴム組成物の調製、及び圧縮永久ひずみの評価を行った。アクリルゴムの製造条件及び圧縮永久ひずみの評価結果（比較例２－１の圧縮永久ひずみを１００としたときの各実施例の圧縮永久ひずみの相対値）を表２に示す。 <Examples 2-1 to 2-2 and Comparative Example 2-1>
In the production of acrylic rubber, the procedure was the same as in Example 1-1, except that the composition of the monomer mixture was changed to 80 parts by mass of ethyl acrylate, 20 parts by mass of n-butyl acrylate, and 4.00 parts by mass of monobutyl maleate. , production of acrylic rubber, preparation of rubber composition, and evaluation of compression set. Table 2 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (the relative value of the compression set of each example when the compression set of Comparative Example 2-1 is set to 100).
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
＜実施例３－１及び比較例３－１＞
　アクリルゴムの製造において、モノマー混合物の組成を、エチルアクリレート４６質量部、ｎ－ブチルアクリレート２６質量部、ｎ－ブチルメタクリレート２８質量部、及びマレイン酸モノブチル４．００質量部に変更した以外は、実施例１－１と同様にして、アクリルゴムの製造、ゴム組成物の調製、及び圧縮永久ひずみの評価を行った。アクリルゴムの製造条件及び圧縮永久ひずみの評価結果（比較例３－１の圧縮永久ひずみを１００としたときの実施例の圧縮永久ひずみの相対値）を表３に示す。 <Example 3-1 and Comparative Example 3-1>
In the production of acrylic rubber, except that the composition of the monomer mixture was changed to 46 parts by weight of ethyl acrylate, 26 parts by weight of n-butyl acrylate, 28 parts by weight of n-butyl methacrylate, and 4.00 parts by weight of monobutyl maleate. Production of acrylic rubber, preparation of rubber composition, and evaluation of compression set were carried out in the same manner as in Example 1-1. Table 3 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (relative value of the compression set of the example when the compression set of Comparative Example 3-1 is set to 100).
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
＜実施例４－１～４－２及び比較例４－１＞
　アクリルゴムの製造において、モノマー混合物の組成を、酢酸ビニル２０．９質量部、メチルアクリレート１０．４質量部、ｎ－ブチルアクリレート６８．７質量部、及びグリシジルメタクリレート１．５５質量部に変更し、凝固剤を、ホウ酸ナトリウム２．５質量部及び硫酸アンモニウム１．５質量部の混合物に変更した以外は、実施例１－１と同様にして、アクリルゴムを製造した。 <Examples 4-1 to 4-2 and Comparative Example 4-1>
In the production of acrylic rubber, changing the composition of the monomer mixture to 20.9 parts by weight of vinyl acetate, 10.4 parts by weight of methyl acrylate, 68.7 parts by weight of n-butyl acrylate, and 1.55 parts by weight of glycidyl methacrylate, An acrylic rubber was produced in the same manner as in Example 1-1, except that the coagulant was changed to a mixture of 2.5 parts by mass of sodium borate and 1.5 parts by mass of ammonium sulfate.
　続いて、得られた各アクリルゴム１００質量部と以下の成分とを８インチオープンロールで混練することにより、ゴム組成物を得た。
　充填剤：カーボンブラック（東海カーボン社製　シーストＳＯ）５０質量部
　滑剤：ステアリン酸（花王社製　ルナックＳ－９０）１質量部、及びステアリルアミン（花王社製　ファーミン８０）０．３質量部
　老化防止剤：４，４’－ビス（α，α－ジメチルベンジル）ジフェニルアミン（アディバント社製　Ｎａｕｇａｒｄ＃４４５）１質量部
　界面活性剤：ラウリル硫酸ナトリウム（花王社製　エマール０）１質量部
　架橋剤：１－（２－シアノエチル）－２－メチルイミダゾール（四国化成工業社製　ＣＮ－２５）１．４質量部
　架橋促進剤：安息香酸アンモニウム（大内新興社製　バルノックＡＢ）０．３質量部 Subsequently, 100 parts by mass of each of the obtained acrylic rubbers and the following components were kneaded with an 8-inch open roll to obtain a rubber composition.
Filler: 50 parts by mass of carbon black (Sheast SO manufactured by Tokai Carbon Co., Ltd.) Lubricant: 1 part by mass of stearic acid (Lunac S-90 manufactured by Kao Corporation) and 0.3 parts by mass of stearylamine (Furmin 80 manufactured by Kao Corporation) Anti-aging Agent: 4,4'-bis (α, α-dimethylbenzyl) diphenylamine (Naugard #445 manufactured by Addivant) 1 part by weight Surfactant: sodium lauryl sulfate (EMAL 0 manufactured by Kao Corporation) 1 part by weight Cross-linking agent: 1- (2-Cyanoethyl) -2-methylimidazole (CN-25 manufactured by Shikoku Kasei Co., Ltd.) 1.4 parts by mass Crosslinking accelerator: ammonium benzoate (Barnok AB manufactured by Ouchi Shinko Co., Ltd.) 0.3 parts by mass
　得られた各ゴム組成物について、実施例１－１と同様にして、圧縮永久ひずみの評価を行った。アクリルゴムの製造条件及び圧縮永久ひずみの評価結果（比較例４－１の圧縮永久ひずみを１００としたときの各実施例の圧縮永久ひずみの相対値）を表４に示す。 For each rubber composition obtained, the compression set was evaluated in the same manner as in Example 1-1. Table 4 shows the production conditions of the acrylic rubber and the evaluation results of the compression set (the relative value of the compression set of each example when the compression set of Comparative Example 4-1 is set to 100).
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　１…押出機、２…凝固ゾーン、３…第一の排水ゾーン、４…第一の洗浄ゾーン、５…第二の排水ゾーン、６…第二の洗浄ゾーン、７…第三の排水ゾーン、８…乾燥ゾーン。 DESCRIPTION OF SYMBOLS 1... extruder, 2... coagulation zone, 3... first drainage zone, 4... first washing zone, 5... second drainage zone, 6... second washing zone, 7... third drainage zone, 8... Drying zone.

Claims (5)

  1. 　アルキルアクリレートを含むモノマーを乳化剤の存在下で乳化重合してアクリルポリマーを得る工程と、
    　前記アクリルポリマー及び前記乳化剤を含有するラテックスと、凝固剤を含有する凝固液とを混合して、前記アクリルポリマーを凝固させる工程と、を備え、
    　前記ラテックスと前記凝固液との混合物中の前記アクリルポリマーの含有量が、前記混合物全量を基準として２０質量％以下である、アクリルゴムの製造方法。     a step of emulsion polymerizing a monomer containing an alkyl acrylate in the presence of an emulsifier to obtain an acrylic polymer;
    a step of mixing the latex containing the acrylic polymer and the emulsifier with a coagulating liquid containing a coagulant to coagulate the acrylic polymer;
    A method for producing acrylic rubber, wherein the content of the acrylic polymer in the mixture of the latex and the coagulating liquid is 20% by mass or less based on the total amount of the mixture.
  2. 　前記ラテックス中の前記アクリルポリマーの含有量が、前記ラテックス全量を基準として３０質量％以上であり、
    　前記混合物中の前記ラテックスの含有量に対する前記凝固液の含有量の質量比が０．６以上である、請求項１に記載のアクリルゴムの製造方法。     The content of the acrylic polymer in the latex is 30% by mass or more based on the total amount of the latex,
    2. The method for producing acrylic rubber according to claim 1, wherein the mass ratio of the content of said coagulating liquid to the content of said latex in said mixture is 0.6 or more.
  3. 　前記ラテックス中の前記アクリルポリマーの含有量が、前記ラテックス全量を基準として３０質量％未満である、請求項１に記載のアクリルゴムの製造方法。 The method for producing acrylic rubber according to claim 1, wherein the content of the acrylic polymer in the latex is less than 30% by mass based on the total amount of the latex.
  4. 　前記モノマーが架橋席モノマーを更に含む、請求項１～３のいずれか一項に記載のアクリルゴムの製造方法。 The method for producing acrylic rubber according to any one of claims 1 to 3, wherein the monomer further contains a cross-linking monomer.
  5. 　前記架橋席モノマーが、カルボキシル基を有する架橋席モノマーである、請求項４に記載のアクリルゴムの製造方法。 The method for producing acrylic rubber according to claim 4, wherein the cross-linking monomer is a cross-linking monomer having a carboxyl group.
PCT/JP2022/030307 2021-08-23 2022-08-08 Method for producing acrylic rubber WO2023026841A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07268169A (en) * 1994-03-30 1995-10-17 Japan Synthetic Rubber Co Ltd Rubber-dispersed synthetic resin composition and its production
JP2002187901A (en) * 2000-12-21 2002-07-05 Denki Kagaku Kogyo Kk Process for preparation of carboxyl group-containing rubber
WO2018116828A1 (en) * 2016-12-19 2018-06-28 日本ゼオン株式会社 Method for producing acrylic rubber
WO2018180978A1 (en) * 2017-03-28 2018-10-04 日本ゼオン株式会社 Method for producing carboxyl-group-containing nitrile rubber

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07268169A (en) * 1994-03-30 1995-10-17 Japan Synthetic Rubber Co Ltd Rubber-dispersed synthetic resin composition and its production
JP2002187901A (en) * 2000-12-21 2002-07-05 Denki Kagaku Kogyo Kk Process for preparation of carboxyl group-containing rubber
WO2018116828A1 (en) * 2016-12-19 2018-06-28 日本ゼオン株式会社 Method for producing acrylic rubber
WO2018180978A1 (en) * 2017-03-28 2018-10-04 日本ゼオン株式会社 Method for producing carboxyl-group-containing nitrile rubber

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