	US 12,384,908 B2
	Multilayer polypropylene film for capacitor
Jun Birukawa, Ichihara (JP); Satoshi Tamura, Sodegaura (JP); and Hiroki Shimizu, Chiba (JP)
Assigned to PRIME POLYMER CO., LTD., Tokyo (JP)
Appl. No. 17/908,896
Filed by PRIME POLYMER CO., LTD., Tokyo (JP)
PCT Filed Feb. 3, 2021, PCT No. PCT/JP2021/003914 § 371(c)(1), (2) Date Sep. 1, 2022, PCT Pub. No. WO2021/176930, PCT Pub. Date Sep. 10, 2021.
Claims priority of application No. 2020-038760 (JP), filed on Mar. 6, 2020.
Prior Publication US 2023/0088053 A1, Mar. 23, 2023
Int. Cl. C08L 23/12 (2006.01); B32B 27/08 (2006.01); B32B 27/32 (2006.01); C08F 110/06 (2006.01); H01G 2/08 (2006.01)

CPC C08L 23/12 (2013.01) [B32B 27/08 (2013.01); B32B 27/32 (2013.01); C08F 110/06 (2013.01); B32B 2250/242 (2013.01); B32B 2307/414 (2013.01); B32B 2307/538 (2013.01); B32B 2457/16 (2013.01); H01G 2/08 (2013.01)]

5 Claims

1. A multilayer polypropylene film for a capacitor comprising a base layer composed of a propylene polymer composition containing a propylene homopolymer (X) and 0.0001 to 0.05 mass % of a polymer-based α-crystal nucleating agent (C), and a front layer on one side of the base layer and a back layer on the other side of the base layer,

wherein the front layer and the back layer consist of a propylene-based polymer (Y) or of the propylene-based polymer (Y) and an additive selected from the group consisting of an antioxidant and calcium sterate,

wherein the base layer, the front layer, and the back layer are stretched, and

wherein a surface roughness Ra of the front layer and of the back layer is 0.2 μm or more.