A process for preparing a rubber article involves modifying the crosslinking density in one region of the article relative to another region of the article. The modification can be carried out by increasing or decreasing the energy transferred to the first region relative to the energy transferred to the second region during vulcanization. In one implementation, the process is conducted in a mold. Rubber parts described have two or more regions that differ from one another with respect to their crosslinking density.

A process for preparing a rubber article involves modifying the crosslinking density in one region of the article relative to another region of the article. The modification can be carried out by increasing or decreasing the energy transferred to the first region relative to the energy transferred to the second region during vulcanization. In one implementation, the process is conducted in a mold. Rubber parts described have two or more regions that differ from one another with respect to their crosslinking density.

A chloroprene rubber composition comprising 0.8 to 4 parts by weight of 2,4,6-trimercapto-s-triazine and 0.5 to 4.5 parts by weight of tetrabenzylthiuram disulfide based on 100 parts by weight of chloroprene rubber. The chloroprene rubber composition maintains processability (scorch time) and productivity (crosslinking rate) equivalent to those of conventionally used crosslinking systems, without using substances subject to environmental regulations in crosslinking systems, and at the same time, improves physical properties, such as strength, elongation, and compression set characteristics.

A chloroprene rubber composition comprising 0.8 to 4 parts by weight of 2,4,6-trimercapto-s-triazine and 0.5 to 4.5 parts by weight of tetrabenzylthiuram disulfide based on 100 parts by weight of chloroprene rubber. The chloroprene rubber composition maintains processability (scorch time) and productivity (crosslinking rate) equivalent to those of conventionally used crosslinking systems, without using substances subject to environmental regulations in crosslinking systems, and at the same time, improves physical properties, such as strength, elongation, and compression set characteristics.

A photochromic curable composition comprising a radically polymerizable monomer having at least one oxetanyl group in one molecule, a photochromic compound and radically polymerizable monomers other than the above polymerizable monomer, and a photochromic cured body obtained by polymerizing the photochromic curable composition.

A photochromic curable composition comprising a radically polymerizable monomer having at least one oxetanyl group in one molecule, a photochromic compound and radically polymerizable monomers other than the above polymerizable monomer, and a photochromic cured body obtained by polymerizing the photochromic curable composition.

A method for producing a resin composition of the present invention is a method for producing a resin composition, the method including a step of obtaining a resin composition by heating and melt-kneading a mixture containing a particulate nucleating agent in which D.sub.50 is equal to or more than 0.1 μm and equal to or less than 300 μm and a thermoplastic resin using a twin screw extruder (100) including, inside a cylinder (10), a screw (50) having kneading discs (60), in which the step of obtaining a resin composition includes an extrusion step of extruding the mixture supplied into the twin screw extruder (100) in an ejection direction under kneading conditions in which X and Y satisfy 4.0≤X in a range of 6.0×10.sup.3≤Y≤7.0×10.sup.4 when a volume-based ejection amount is denoted by X (10.sup.−6.Math.kg.Math.h.sup.−1.Math.mm.sup.−3), and a strain rate is denoted by Y (min.sup.−1).

A method for producing a resin composition of the present invention is a method for producing a resin composition, the method including a step of obtaining a resin composition by heating and melt-kneading a mixture containing a particulate nucleating agent in which D.sub.50 is equal to or more than 0.1 μm and equal to or less than 300 μm and a thermoplastic resin using a twin screw extruder (100) including, inside a cylinder (10), a screw (50) having kneading discs (60), in which the step of obtaining a resin composition includes an extrusion step of extruding the mixture supplied into the twin screw extruder (100) in an ejection direction under kneading conditions in which X and Y satisfy 4.0≤X in a range of 6.0×10.sup.3≤Y≤7.0×10.sup.4 when a volume-based ejection amount is denoted by X (10.sup.−6.Math.kg.Math.h.sup.−1.Math.mm.sup.−3), and a strain rate is denoted by Y (min.sup.−1).

An object of the present invention is to provide a colored curable resin composition for forming an optical filter in which the occurrence of foreign matter is reduced. The present invention relates to a colored curable resin composition containing a colorant, a resin, a polymerizable compound, and a polymerization initiator, wherein the colorant is a colorant containing a compound represented by formula (I) or formula (II).

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An object of the present invention is to provide a colored curable resin composition for forming an optical filter in which the occurrence of foreign matter is reduced. The present invention relates to a colored curable resin composition containing a colorant, a resin, a polymerizable compound, and a polymerization initiator, wherein the colorant is a colorant containing a compound represented by formula (I) or formula (II).

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