| 摘要 |
In a modification of a process in which films or sheets of polymers of oxymethylene or of oxymethylene containing minor proportions of oxyalkylene, preferably oxyethylene, units, are united to substrate films or rigid layers of other polymeric materials capable of softening into adhesive condition, for example by applying heat and pressure sufficient to soften the contacted layers or by using liquids such as phenols, dimethyl formamide or benzyl alcohol which are partial solvents for the layers for softening them, the polymer in powder or granule form is formed into a film by hot-pressing between one such layer and p an aluminium foil which is subsequently removed. Suitable substrates are films or rigid sheets of polyethylene terephthalate, polythene, polypropylene, cellulose esters, vinyl chloride-vinylidene chloride copolymers, polyvinyl chloride, polymethyl methacrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, and polyamides. Specifications 877,820 and 903,668 are referred to. |
