| 摘要 |
<p>1,150,458. Laminated pigmented unitary films. E. I. DU PONT DE NEMOURS & CO. 5 Dec., 1966 [6 Dec., 1965], No. 54332/66. Heading B5B. An integral biaxially oriented film of organic thermoplastic polymeric material has at least two strata characterized in that each of the contiguous strata contains an opacifying coloration pigment differing from or the same as that contained by the other stratum, in the same or in a different concentration. Each stratum contains 0À5 to 60% by weight, based on the polymeric material in the stratum, of the opacifying coloration pigment. The film is also characterized in that at least one of the variables, the thermoplastic material, the opacifying coloration pigment and the pigment concentration is different. One of the film strata may be more opaque than the other or others. The pigment may be titanium dioxide or carbon black. The organic thermoplastic material may be polyvinyl fluoride. The colour of one stratum may differ from that of the adjacent stratum. There may be no distinct interface between adjacent strata of the film. An integral biaxially oriented film of organic thermoplastic polymeric material having a plurality of strata wherein at least one stratum contains opacifying coloration pigment may be made by simultaneously melt extruding two or more pigmented melts corresponding to the strata of the film to be formed through contiguous slot dies to form separate flat films which are contacted while they are still hot plastic and adhesive and bonding these together to form a composite stratified film. The film is then quenched and elongated and widened to orient it biaxially. The unitary film may be made by heating and mixing two or more mixtures comprising polyvinyl fluoride, a latent solvent for polyvinyl fluoride and the same or different opacifying coloration pigments in the same or different amounts to form homogeneous single phase liquid compositions, simultaneously extruding two or more films from the compositions, contacting the films to form an integral film; quenching the integral film and stretching it in two mutually perpendicular directions while simultaneously evolving latent solvent therefrom followed by drying the film to remove substantially all of the remaining latent solvent.</p> |
