Patent ID: 6756002
Filing Date: 2004-06-29
Classification: B29C

Abstract:
A method of producing a thermoplastic resin sheet, using a producing apparatus in which a first metallic endless belt, having a mirror face is wound on and extends between a first endless belt supporting cooling roller covered with an elastic member on a surface and a second endless belt supporting cooling roller spaced from the first cooling roller, and a second metallic endless belt having a mirror face is wound on end extends between a third endless belt supporting cooling roller and a fourth endless belt supporting cooling roller, the first and second metallic endless belts being coextensive so as to run along side each other to sandwich a molten thermoplastic resin sheet therebetween, and an added-pressure device for both said metallic endless belts being provided in a section where both said metallic endless belts run along side each other sandwiching the molten thermoplastic resin sheet there between, the method comprising the steps of:guiding the molten thermoplastic resin sheet into an area between the first and second metallic endless belts to touch the first endless belt and the second metallic endless belt at approximately the same time a the temperature of at least one of the metallic endless belts directly touching the molten thermoplastic resin sheet is retained at less than 50Â° C.; touch-rolling and cooling the molten thermoplastic resin sheet along a nip width of at least 5 mm between the first and third endless belt supporting cooling rollers while the elastic member is elastically deformed by a pressing force between the first and third endless belt supporting cooling rollers; and cooling, subsequently, the molten thermoplastic resin sheet by touch-rolling the molten thermoplastic resin sheet using the added-pressure device in a section where both said metallic endless belts run along side each other; wherein when the molten thermoplastic resin sheet is touch-rolled on the face with the elastic deformation of the elastic member, the face pressure is defined in the range from 0.1 MPa to 20 MPa; and wherein when the molten thermoplastic resin sheet is touch-rolled on the face without the elastic deformation of the elastic member, the face pressure is in a range from 0.01 MPa to 0.5 MPa.