The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1993
Filed:
May. 22, 1992
Toyokazu Yamada, Himeji, JP;
Idemitsu Petrochemical Co., Ltd., Tokyo, JP;
Abstract
A method for recovering and reusing a scrap multilayer plastic sheet or film comprising at least a base material layer and laminated with an adhesive resin comprising at least one of an ethylene-vinyl acetate copolymer, a styrene-isoprene copolymer, a styrene-butadiene copolymer, a styrene-methyl methacrylate copolymer and an ethylene-acrylic acid ester-maleic anhydride copolymer. The method comprises heating the scrap multilayer sheet or film to a temperature lower than the softening point of the base material layer to make the interlaminar peeling strength of the adhesive resin lower than the strength at break of a layer having the lowest strength at break, except for the adhesive layer, and separating the multilayer scrap into at least two scrap layers and recovering at least one scrap layer in sheet or film form. The present invention provides effective reuse of scrap with almost no reduction in physical properties. Furthermore the cost of the production or molding of the sheet can be reduced. Still further, it is not necessary to add an additive, a white pigment and the like for preventing thermal deterioration. When polypropylene is used as a base material in the present method, it is not necessary to use low viscosity polypropylene as is conventionally required. That is, since high viscosity polypropylene can be used, vacuum molding becomes easy and furthermore a multilayer sheet or film having desirable physical properties can be produced very economically.