Abstract: A polymer powder (P) selected from a group consisting of (i) a polymer powder (P1) and (ii) a polymer powder (P2) is provided. The (i) polymer powder (P1) includes a (meth)acrylate-based polymer (A1) having a glass transition temperature of 0° C. or less, and the polymer powder has an acetone-soluble component of 5 mass % or more. The acetone-soluble component has a mass average molecular weight of 100,000 or more. The (ii) polymer powder (P2) has an acetone-soluble component of 2 mass % to 35 mass %, the acetone-soluble component has a mass average molecular weight of 100,000 or more, and has a volume average primary particle size (Dv) of 200 nm or more.

Abstract: A polymer powder (P) selected from a group consisting of (i) a polymer powder (P1) and (ii) a polymer powder (P2) is provided. The (i) polymer powder (P1) includes a (meth)acrylate-based polymer (A1) having a glass transition temperature of 0° C. or less, and the polymer powder has an acetone-soluble component of 5 mass % or more. The acetone-soluble component has a mass average molecular weight of 100,000 or more. The (ii) polymer powder (P2) has an acetone-soluble component of 2 mass % to 35 mass %, the acetone-soluble component has a mass average molecular weight of 100,000 or more, and has a volume average primary particle size (Dv) of 200 nm or more.

Abstract: A polymer powder (P) selected from a group consisting of (i) a polymer powder (P1) and (ii) a polymer powder (P2) is provided. The (i) polymer powder (P1) includes a (meth)acrylate-based polymer (A1) having a glass transition temperature of 0° C. or less, and the polymer powder has an acetone-soluble component of 5 mass % or more. The acetone-soluble component has a mass average molecular weight of 100,000 or more. The (ii) polymer powder (P2) has an acetone-soluble component of 2 mass % to 35 mass %, the acetone-soluble component has a mass average molecular weight of 100,000 or more, and has a volume average primary particle size (Dv) of 200 nm or more.

Abstract: A polymer powder (P) selected from a group consisting of (i) a polymer powder (P1) and (ii) a polymer powder (P2) is provided. The (i) polymer powder (P1) includes a (meth)acrylate-based polymer (A1) having a glass transition temperature of 0° C. or less, and the polymer powder has an acetone-soluble component of 5 mass % or more. The acetone-soluble component has a mass average molecular weight of 100,000 or more. The (ii) polymer powder (P2) has an acetone-soluble component of 2 mass % to 35 mass %, the acetone-soluble component has a mass average molecular weight of 100,000 or more, and has a volume average primary particle size (Dv) of 200 nm or more.

Abstract: A vinyl polymer powder, a curable resin composition containing the vinyl polymer powder and a curable resin, and a cured product obtained by curing the curable resin composition are provided. The vinyl polymer powder contains a vinyl polymer of which the glass transition temperature is 120° C. or higher and the mass average molecular weight is 100,000 or more, has excellent dispersibility in the curable resin composition, and rapidly turns the curable resin composition into a gel state by heating at a predetermined temperature in a short time. Further, the vinyl polymer powder decreases the linear expansion coefficient of the obtained cured product, and improves the crack resistance.

Abstract: An epoxy resin composition, a cured object thereof, and an optical semiconductor sealing material using the cured object are described. The epoxy resin composition includes an alicyclic epoxy resin (A) and a vinyl polymer particle (B). An acetone soluble part of the vinyl polymer particle (B) is 30 mass % or more. The mass average molecular weight of the acetone soluble part is 100,000 or more. The volume average primary particle diameter (Dv) is 200 nm or more. The epoxy resin composition is rapidly turned into a gel state by heating for a short time, and the transparency of the obtained cured object is good.

Abstract: To provide a processing aid for a polyolefin-based resin, capable of providing a polyolefin-based resin composition having excellent melt tension, fluidity and die build-up inhibiting effect. A processing aid for a polyolefin-based resin, comprising (A) an alkyl methacrylate-based polymer containing, as a main component, a unit of (a1) an alkyl methacrylate in which the alkyl group has 2 to 10 carbon atoms, and having a mass average molecular weight of 15,000 to 145,000.

Abstract: Disclosed are a powdery processing aid for polyolefin resins, containing an alkyl methacrylate polymer which has alkyl methacrylate units having an alkyl group with 2 to 6 carbon atoms as a main component and has a mass average molecular weight of 150,000 to 20,000,000, having good handling properties as a powder, having good dispersibility in polyolefin resins, and being able to improve shaping processability of polyolefin resins; and a polyolefin resin composition having improved shaping processability, which contains a powdery processing aid for polyolefin resins and a polyolefin resin.

Abstract: Disclosed are a powdery processing aid for polyolefin resins, containing an alkyl methacrylate polymer which has alkyl methacrylate units having an alkyl group with 2 to 6 carbon atoms as a main component and has a mass average molecular weight of 150,000 to 20,000,000, having good handling properties as a powder, having good dispersibility in polyolefin resins, and being able to improve shaping processability of polyolefin resins; and a polyolefin resin composition having improved shaping processability, which contains a powdery processing aid for polyolefin resins and a polyolefin resin.