Multi-layer film with core layer of syndiotactic polypropylene

A biaxially oriented multi-layer film which comprises:

• (a) a core layer comprising a syndiotactic propylene polymer;
• (b) a first outer layer adjacent to a first side of the core layer wherein the first outer layer comprises a material selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof;
• (c) a second outer layer applied to an outer surface of the first outer layer, wherein the second outer layer comprises a material selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof;
• (d) a third outer layer adjacent to a second side of the core layer, wherein the third outer layer comprises a material selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof;
• (e) a fourth outer layer applied to an outer surface of the third outer layer, wherein the fourth outer layer comprises a material selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof;
• and
• (f) wherein the film has a modulus measured in the transverse direction and a modulus measured in the machine direction and the ratio of the modulus in the transverse direction to the modulus in the machine direction is from about 1.53 to about 1.95.

A process for preparing a biaxially oriented multi-layer film comprising the steps of:

• (a) melt coextruding a film comprising:
• (i) a core layer comprising at least about 90 wt. % of a syndiotactic polypropylene, (ii) a first additional layer adjacent to a first side of the core layer comprising materials selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof, and (iii) a second additional layer adjacent to a second side of the core layer comprising materials selected from the group consisting of butene-1-propylene random copolymer, ethylene-propylene block copolymer, nylon, polyester, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-propylene-butene-1 random terpolymer containing 1 to 5 wt. % random ethylene and 10 to 25 wt. % random butene-1, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and blends thereof, and
• (b) biaxially orienting the coextruded combination in a machine and a transverse direction to form a film having a modulus measured in the transverse direction and a modulus measured in the machine direction and the ratio of the modulus in the transverse direction to the modulus in the machine direction is from about 1.53 to about 1.95.