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A composite film structure composed of a layer (A) of high density polyethylene having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.3-2.9 dl/g, a melt index (MI A ) of 0.3-7.0 g/10 min. and a density of 0.950-0.970 g/cm 3, in which up to 2 mole % of an alpha-olefin may be contai

A composite film structure composed of a layer (A) of high density polyethylene having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.3-2.9 dl/g, a melt index (MI A ) of 0.3-7.0 g/10 min. and a density of 0.950-0.970 g/cm 3, in which up to 2 mole % of an alpha-olefin may be contained; and layers (B) of an ethylene/C 5 -C 10 alpha-olefin random copolymer having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.0-2.4 dl/g, a melt index (MI B ) of 0.5-20 g/10 min., a density of 0.910-0.940 g/cm 3, and a melting point of 115°-130° C., with the proviso that the MI A /MI B ratio is 0.15-4.0, said layers (B) being in direct contact with the two sides of said layer (A) and laminated thereto.

대표청구항 ▼

1. A composite film structure composed of a layer (A) of high density polyethylene having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.3-2.9 dl/g, a melt index (MI A ) of 0.3-7.0 g/10 min. and a density of 0.950-0.970 g/cm 3, in which up to 2 mole % of an alpha-olefin may be con

1. A composite film structure composed of a layer (A) of high density polyethylene having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.3-2.9 dl/g, a melt index (MI A ) of 0.3-7.0 g/10 min. and a density of 0.950-0.970 g/cm 3, in which up to 2 mole % of an alpha-olefin may be contained; and layers (B) of an ethylene/C 5 -C 10 alpha-olefin random copolymer having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.0-2.4 dl/g, a melt index (MI B ) of 0.5-20 g/10 min., a density of 0.910-0.940 g/cm 3, and a melting point of 115°-130° C., with the proviso that the MI A /MI B ratio is 0.15-4.0, said layers (B) being in direct contact with the two sides of said layer (A) and laminated thereto. 2. A composite film structure as defined in claim 1 wherein said MI A /MI B ratio is 0.4-2.0. 3. A composite film structure as defined in claim 1 wherein said ethylene random copolymer is an ethylene/C 6 -C 8 alpha-olefin copolymer. 4. A composite film structure as defined in claim 1 wherein said high density polyethylene is one having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.6-2.4 dl/g, a melt index (MI A ) of 0.5-3.0 g/10 min., and a density of 0.950-0.965 g/cm 3 . 5. A composite film structure as defined in claim 1 wherein said ethylene random copolymer is one having an intrinsic viscosity [η] as measured in decalin at 135° C. of 1.2-2.0 dl/g, a melt index (MI B ) of 1.0-10 g/10 min., a density of 0.915-0.935 g/cm 3, and a melting point of 115°-125° C. 6. A composite film structure as defined in claim 1 wherein the thicknesses of said layers (A) and (B) are 5-100 microns and 1-20 microns, respectively. 7. A composite film structure as defined in claim 1 wherein the ethylene random copolymer has an ethylene content of from about 90 mole% to about 99.5 mole%.