Process for production of polypropylene sheets or films
AssigneeIdemitsu Petrochemical Co., Ltd.
InventorAtsushi Fujii
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Abstract
A process for producing a polypropylene resin sheet or film by introducing a polypropylene resin in a film form, which has been extruded from a T-die in a molten state, into a slit through which cooling water is flowing, passing the polypropylene resin film between nip rolls, and pressing the obtained sheet or film from both sides thereof under a pressure of at least 5 kg/cm.sup.2, while heating at a temperature of 155.degree. to 160.degree. C., by the use of a metal belt having a surface roughness of not more than 0.1 .mu.m. The process produces a sheet or film of a polypropylene resin which is unstretched and is excellent in transparency, surface gloss and heat moldability.
Claims11
A process for producing a polypropylene resin sheet or film which comprises
- (a) introducing a polypropylene resin in a film form, which has been extruded from a T-die in a molten state, into a slit through which cooling water is flowing,
- (b) passing the polypropylene resin film between nip rolls of the half immersed type, said nip rolls in contact with a lower water bath, and
- (c) pressing between a pair of metal bolts the obtained sheet or film from both sides thereof under a pressure of at least 5 kg/cm.sup.2, while heating at a temperature of 155.degree. to 160.degree. C., said metal belts having a surface roughness of not more than 0.1 .mu.m.
Dependencies are inferred from the claim text.