Abstract: An object is to produce a collagen vitrigel, which has a high film strength even without performing a crosslinking treatment, and is easily produced and processed industrially and mechanically, and is also easy to handle and is highly safe, from collagen, and a purified product thereof. In order to achieve the object, it is directed to a method for producing a collagen vitrigel characterized by gelling collagen with a gelling agent containing an inorganic carbonate and a compound selected from the group consisting of an inorganic chloride and an inorganic phosphate, subsequently vitrifying the obtained collagen gel, and further subjecting the vitrified collagen gel to a hydration treatment; a method for producing a purified collagen vitrigel characterized by desalting, equilibrating, and further drying the collagen vitrigel; and a collagen vitrigel and a purified collagen vitrigel obtained by these methods.

Abstract: A method for producing an acrylic rubber, the method including dividedly adding 80% to 100% by mass of the total mass of a monomer component containing 100 parts by mass of an acrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms, 20 to 160 parts by mass of an acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms, and 0.1 to 10 parts by mass of a crosslinking seat monomer containing a carboxyl group, and performing emulsion polymerization at a polymerization temperature of 20° C. to 60° C. The monomer component may further contain a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and ethylene.

Abstract: Provided are an acrylic rubber composition having higher tensile properties and higher heat resistance and a vulcanizate thereof. An acrylic rubber composition includes 1 to 25 parts by mass of a layered clay mineral relative to 100 parts by mass of an acrylic rubber. The acrylic rubber is a copolymer of a (meth)acrylic acid alkyl ester and a curesite monomer.

Abstract: Provided are an acrylic rubber composition having higher tensile properties and higher heat resistance and a vulcanizate thereof. The present invention provides an acrylic rubber composition includes 0.1 to 50 parts by mass of a carbon material includes graphene oxide, relative to 100 parts by mass of an acrylic rubber.

Abstract: Provided are a laminate body, a cross-linked product, and a molded member superior in interlayer adhesiveness. An acrylic elastomer layer 11 is prepared from an acrylic elastomer composition containing an epoxy group-containing acrylic elastomer as major component, an onium salt in an amount of 1 to 5 parts by mass and a polyol compound in an amount of 1 to 8 parts by mass with respect to 100 parts by mass of the acrylic elastomer, and a fluorine-based elastomer layer 12 is prepared from a fluorine-based elastomer composition containing a polyol crosslinking agent. The acrylic elastomer layer 11 and the fluorine-based elastomer layer 12 are laminated, to give a laminate body 1. The laminate body 1 is cross-linked, to give a cross-linked product or a molded member.

Abstract: Provided is a laminate having elastomer layers tightly bonded to each other. The laminate according to the present invention 1 has an acrylic elastomer layer 11 and a fluorine elastomer layer 12 that are bonded to each other. The acrylic elastomer layer 11 is made of an acrylic elastomer composition having an epoxy group-containing acrylic elastomer and an onium salt added and the fluorine elastomer layer 12 is made of a fluorine elastomer composition having a fluorine elastomer and a polyol crosslinking agent added. In the laminate 1, the elastomer layers are bonded tightly to each other even without any surface treatment.

Abstract: To provide an acrylic rubber composition and its vulcanized product, having excellent workability and an excellent balance of the vulcanization properties, the reduction of scorching, the rubber mechanical properties, the compression set and the heat resistance. An acrylic rubber composition comprising a carboxy group-containing acrylic rubber, a novolac phenol resin salt of a diazabicycloalkene compound and a polyamine compound. Particularly, the diazabicycloalkene compound is preferably 2,3,4,6,7,8,9,10-octahydropyrimido(1,2-a)azepine or 2,3,4,6,7,8-hexahydropyrrolo(1,2-a)pyrimidine, and the polyamine compound is preferably an aromatic polyamine or an aliphatic polyamine.

Abstract: Provided are a laminate body, a cross-linked product, and a molded member superior in interlayer adhesiveness. An acrylic elastomer layer 11 is prepared from an acrylic elastomer composition containing an epoxy group-containing acrylic elastomer as major component, an onium salt in an amount of 1 to 5 parts by mass and a polyol compound in an amount of 1 to 8 parts by mass with respect to 100 parts by mass of the acrylic elastomer, and a fluorine-based elastomer layer 12 is prepared from a fluorine-based elastomer composition containing a polyol crosslinking agent. The acrylic elastomer layer 11 and the fluorine-based elastomer layer 12 are laminated, to give a laminate body 1. The laminate body 1 is cross-linked, to give a cross-linked product or a molded member.

Abstract: Provided is an acrylic rubber composition including an acrylic rubber and a functionalized silicone oil. Here, the functionalized silicone oil preferably has a particular polydimethylsiloxane structure having at least one binding site bonded with at least one of a monoamino group, a diamino group, a polyether group, an epoxy group, an alicyclic epoxy group, a hydroxyl group, a thiol group, a carboxyl group, a hydrogen group (Si—H group), a methacryl group, a phenol group, an alkoxy group, an ester group, an amide group, an alkyl group, a fluoroalkyl group, and a diol group and has a functional group equivalent weight of 1 to 100,000 (g/mol). The composition is unlikely to be deteriorated even when it is exposed to high temperature for a long time and that has excellent heat resistance and a crosslinked product of the composition.

Abstract: The laminate according to the present invention 1 has an acrylic elastomer layer 11 and a fluorine elastomer layer 12 that are bonded to each other. The acrylic elastomer layer 11 is made of an acrylic elastomer composition having an epoxy group-containing acrylic elastomer and an onium salt added and the fluorine elastomer layer 12 is made of a fluorine elastomer composition having a fluorine elastomer and a polyol crosslinking agent added. In the laminate 1, the elastomer layers are bonded tightly to each other even without any surface treatment.

Abstract: Provided are an acrylic rubber composition higher in processing stability and giving a vulcanizate having sufficient mechanical properties and favorable compression set resistance after secondary vulcanization (heated air vulcanization) and the vulcanizate thereof. The acrylic rubber composition according to the present invention includes (A) an epoxy group-containing acrylic rubber, (B) an imidazole compound represented by General Formula (1) below, (C) silica, and (D) a silane-coupling agent represented by General Formula (2) below. Such an acrylic rubber composition is superior in mechanical properties such as compression set resistance and hardness.

Abstract: The present invention relates to an acrylic rubber composition that is unlikely to be deteriorated even when it is exposed to high temperature for a long time and that has excellent heat resistance and a cross-linked product of the composition. Provided is an acrylic rubber composition including an acrylic rubber and a functionalized silicone oil. Here, the functionalized silicone oil preferably has a particular polydimethylsiloxane structure having at least one binding site bonded with at least one of a monoamino group, a diamino group, a polyether group, an epoxy group, an alicyclic epoxy group, a hydroxyl group, a thiol group, a carboxyl group, a hydrogen group (Si—H group), a methacryl group, a phenol group, an alkoxy group, an ester group, an amide group, an alkyl group, a fluoroalkyl group, and a diol group and has a functional group equivalent weight of 1 to 100,000 (g/mol).

Abstract: In a method for manufacturing a rotor hub for use in a spindle motor, free-cutting stainless steel is used as a material of the rotor hub. A slug of free-cutting stainless steel is subjected to a plastic working to form a disk mounting portion and a cylindrical surface positioned radially inwardly of the disk mounting portion. Then, a cylindrical disk fitting surface is formed by machining substantially the entirety of the cylindrical surface. The rotor hub contains A-type inclusions appearing in a cross section taken along a center axis of the disk mounting portion. The A-type inclusions are oriented in directions different than the center axis.

Abstract: Provided is a sulfur-modified chloroprene elastomer composition superior both in viscosity stability during storage and scorching resistance during processing and a blend and vulcanized article thereof. A sulfur-modified chloroprene elastomer composition, containing a thiuram compound in an amount of 1 to 2.5 mass % and having an organic acid content, as determined in accordance with JIS K6237, of 1.5 to 15 mass %, an ash content, as determined in accordance with JIS K6228, of 0.03 to 0.2 mass %, and a mass ratio of the organic acid content to the ash content (organic acid content/ash content) of 50 to 500, as they are so regulated by modification of the blending amount of the emulsifier.

Abstract: Provided is a polychloroprene elastomer composition superior in extrusion processability and mechanical properties, a production method thereof, and vulcanized and molded articles thereof. A polychloroprene elastomer composition, comprising 100 parts by mass of a polychloroprene elastomer containing a polychloroprene sol and a polychloroprene gel and 0.2 to 5 parts by mass of a thiuram compound, wherein the blending rate of the polychloroprene sol to the polychloroprene gel (sol/gel) is 30/70 to 80/20 by mass.

Abstract: The present invention provides an acrylic rubber composition and its vulcanized product, having good vulcanization characteristics and an excellent balance between processability, mechanical properties of rubber and compression set. The acrylic rubber composition comprises a carboxyl group-containing acrylic rubber, a diazabicycloalkene compound, a polyamine compound, and a tertiary amine compound represented by the following formula (1): where each of R1, R2 and R3 is independently a substituent having at least one saturated aliphatic hydrocarbon or unsaturated aliphatic hydrocarbon having a linear structure, a branched structure or a cyclic structure, or benzyl group.

Abstract: To provide an acrylic rubber composition and a vulcanized rubber that ensure heat resistance of the vulcanized rubber, especially less changes in the elongation at break (EB) and hardness of the vulcanized rubber under heating conditions. An acrylic rubber composition comprising a carboxyl group-containing acrylic rubber and, per 100 parts by mass of the carboxyl group-containing acrylic rubber, from 10 to 100 parts by mass of carbon black, from 0.1 to 15 parts by mass of at least one primary antioxidant selected from the group consisting of an amine antioxidant and a phenolic antioxidant and from 0.1 to 15 parts by mass of at least one secondary antioxidant selected from the group consisting of a phosphorus antioxidant and a sulfur antioxidant.

Abstract: To provide an acrylic rubber composition and its vulcanized product, having excellent workability and an excellent balance of the vulcanization properties, the reduction of scorching, the rubber mechanical properties, the compression set and the heat resistance. An acrylic rubber composition comprising a carboxy group-containing acrylic rubber, a novolac phenol resin salt of a diazabicycloalkene compound and a polyamine compound. Particularly, the diazabicycloalkene compound is preferably 2,3,4,6,7,8,9,10-octahydropyrimido(1,2-a)azepine or 2,3,4,6,7,8-hexahydropyrrolo(1,2-a)pyrimidine, and the polyamine compound is preferably an aromatic polyamine or an aliphatic polyamine.

Abstract: The present invention provides an acrylic rubber composition and its vulcanized product, having good vulcanization characteristics and an excellent balance between processability, mechanical properties of rubber and compression set. The acrylic rubber composition comprises a carboxyl group-containing acrylic rubber, a diazabicycloalkene compound, a polyamine compound, and a tertiary amine compound represented by the following formula (1): where each of R1, R2 and R3 is independently a substituent having at least one saturated aliphatic hydrocarbon or unsaturated aliphatic hydrocarbon having a linear structure, a branched structure or a cyclic structure, or benzyl group.

Abstract: In a method for manufacturing a rotor hub for use in a spindle motor, free-cutting stainless steel is used as a material of the rotor hub. A slug of free-cutting stainless steel is subjected to a plastic working to form a disk mounting portion and a cylindrical surface positioned radially inwardly of the disk mounting portion. Then, a cylindrical disk fitting surface is formed by machining substantially the entirety of the cylindrical surface. The rotor hub contains A-type inclusions appearing in a cross section taken along a center axis of the disk mounting portion. The A-type inclusions are oriented in directions different than the center axis.