Patent ID: 6420021
Filing Date: 2002-07-16
Classification: B32B,C08J,C08L,Y10T

Abstract:
A multi-layered film of propylenic random copolymers, which comprises a surface layer of the following propylenic copolymer (A) as formed on at least one surface of a substrate layer of the following propylenic random copolymer (C), the thickness ratio of the surface layer to the substrate layer being from 0.005:1 to 0.5:1:propylenic random copolymer (C) satisfying the following criteria (15) to (17): (15) the ethylene unit content (xc, wt. %) of the copolymer (C) is from 0.2 to 4 wt. %, (16) the relation between the boiling diethyl ether extraction (Ec, wt. %) of the copolymer (C) and xc satisfies the following equation (XII): Ec&lE;0.25xc+1.1â€ƒâ€ƒ(XII), and(17) the relation between the melting point (Tmc, Â° C.) of the copolymer (C) as measured with a differential scanning calorimeter and xc satisfies the following equation (XIII): Tmc&lE;165âˆ’5xcâ€ƒâ€ƒ(XIII), propylenic random copolymer (A) satisfying the following criteria (1) to (3): (1) the ethylene unit content (xa, wt. %) of the copolymer (A) is from 3 to 10 wt. %, (2) the relation between the boiling diethyl ether extraction (Ea, wt. %) of the copolymer (A) and xa satisfies the following equations (I) or (II): Ea&lE;0.25xa+1.1(xa=3 to 6 wt. %)â€ƒâ€ƒ(I) Ea&lE;2.6(xa=6 to 10 wt. %)â€ƒâ€ƒ(II), and(3) the relation between the melting point (Tmc, Â° C.) of the copolymer (A) as measured with a differential scanning calorimeter and xa satisfies the following equations (III) or (IV): Tmc&lE;140(xa=3 to 5 wt. %)â€ƒâ€ƒ(III) Tmc&lE;165âˆ’5xa(xa=5 to 10 wt. %)â€ƒâ€ƒ(IV).