| 摘要 |
1,254,031. Foamed polyolefine films. IMPERIAL CHEMICAL INDUSTRIES Ltd. 8 May, 1970 [21 May, 1969], No. 25864/69. Headings C3C and C3P. A-film having an opacity of at least 90% (as measured by a given method of test) is composed of a foamed polyolefine composition containing .as an opacifying pigment 5-20% by wt. of titanium dioxide and 0-05-1-0% by wt. of metallic aluminium particles of median particle size (by number) of at least 20 and not more than 20% by wt. of the particles being of size less than 10 Á. The polyolefine may be low density polyethylene with optionally a crystalline polyolefine, or high density polyethylene. The composition may be made by mixing the polyolefine and pigment and then extruding the mixture with nitrogen and petroleum ether as the blowing agent. |
