Low temperature heat-sealable bi-axially oriented polypropylene composite film and process for production thereof
AssigneeHonshu Seishi Kabushiki Kaisha
InventorsMikio Tsuchiya, Takashi Kawamura, Kazuo Ootaka, Yukio Ozaki
Life of this patent
Estimating the term…
Abstract
A novel type of low temperature heat-sealable bi-axially oriented polypropylene composite film and a process for the production thereof are disclosed. The composite film is characterized by having on at least one of the outer surfaces thereof a uni-axially or bi-axially oriented extremely thin continuous layer of a primary higher fatty acid amide or an N-substituted higher fatty acid amide formed through the sequential coating and orientating, and it shows well-balanced excellence in all properties required for such films including lubricity, anti-blocking property, anti-scratch property and low temperature heat sealability.
Claims24
A low temperature heat-sealable bi-axially oriented polypropylene composite film which comprises:
- (a) a substrate layer comprising a bi-axially oriented polypropylene film;
- (b) a uni-axially or bi-axially oriented lamination layer or layers comprising ethylene-butene copolymer or a resin mixture comprising ethylene-butene copolymer laminated on at least one surface of said substrate layer;
- and
- (c) a uni-axially or bi-axially oriented extremely thin continuous layer of a primary higher fatty acid amide or an N-substituted higher fatty acid amide formed through the sequential coating and orientating on at least one of the outer surfaces of the composite film.
A process for the production of low temperature heat-sealable bi-axially oriented polypropylene composite film comprising the steps of
- laminating ethylene-butene copolymer or a resin mixture comprising ethylene-butene copolymer on at least one surface of a substrate sheet of non-oriented or uni-axially oriented polypropylene to form a corresponding non-oriented or uni-axially oriented composite film,
- coating on at least one of the outer surfaces of said composite film a solution of a primary higher fatty acid amide or an N-substituted higher fatty acid amide, and then
- when said coated composite film is non-oriented, bi-axially stretching, heating at a temperature between 130.degree. C. and 180.degree. C. and orienting said non-oriented composite films, and
- when said coated composite film is uni-axially oriented, stretching, heating at a temperature between 130.degree. C. and 180.degree. C. and orienting said composite film containing the uni-axially oriented polypropylene substrate film in the direction perpendicular to the direction in which said substrate polypropylene film has been oriented,
- whereby said bi-axially oriented polypropylene composite film having a very thin adherent layer of said amide on at least one surface is produced.
Dependencies are inferred from the claim text.