Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Layered – stratified traversely of length – or multiphase...
Patent
1991-12-30
1993-04-20
Thurlow, Jeffery
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Layered, stratified traversely of length, or multiphase...
26421112, 264216, 264237, 264280, 425224, 425327, B29C 4790
Patent
active
052040372
ABSTRACT:
A process for producing a polypropylene sheet or film. The process includes (a) providing two opposing cooling rolls which are maintained at a temperature of 10.degree. to 50.degree. C., (b) passing a metallic endless belt having a surface roughness of not more than 1.5 .mu.m under tension, between the opposing cooling rolls, (c) producing a molten sheet or film of a polypropylene composition, the composition comprising polypropylene and at least one additive selected from the group consisting of a nucleating agent, a finely powdered high melting point polymer, a petroleum resin, a terpene resin, an organic peroxide and a crystalline propylene-based copolymer, (d) subjecting the produced sheet or film to a specular finishing treatment by passing the sheet or film between the metallic endless belt and one of the cooling rolls and conveying the sheet or film on the metallic endless belt over a surface portion of at least one of the cooling rolls and (e) separating the sheet or film from the metallic endless belt after the specular finishing treatment. The process results in a polypropylene sheet or film excellent in transparency and surface gloss, although not stretched. Moreover, the process provides high speed production of a polypropylene sheet of film.
REFERENCES:
patent: 3361728 (1968-01-01), Coen et al.
patent: 4548778 (1985-10-01), Fujii
patent: 4863653 (1989-09-01), Takubo et al.
patent: 4867927 (1989-09-01), Funaki et al.
patent: 5026778 (1991-06-01), Fujii et al.
patent: 5118566 (1992-06-01), Wilhelm et al.
Patent Abstracts of Japan, vol. 7, No. 41 (M-194) (1186) Feb. 18, 1983 of JP-A-57 191 020, Nov. 24, 1982.
Derwent Publications Ltd., London, GB; AN 82-2064DE of JP-A-57 022 019, Feb. 4, 1982.
Idemitsu Petrochemical Co. Ltd.
Thurlow Jeffery
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