| 摘要 |
<p>1438984 Embossing HERCULES Inc 5 Sept 1973 [19 Sept 1972] 41716/73 Heading B6J A biaxially oriented embossed propylene polymer film having a thickness no greater than 5 units at its thickest point comprises a plurality of uniform rows of enclosed depressions, each depression being enclosed by a ridge, the film thickness at the ridge being at least 3 times that at the depression and each ridge-enclosed depression being separated from adjacent ridgeenclosed depressions by a valley area wherein the thickness of the film is less than that at the depression, there being between 1 and 240 enclosed depressions per square inch and the polymer having a crystallinity of from 40% to 65%. The film is prepared by embossing a sheet of propylene polymer of a thickness no greater than 18 mils. and having a crystallinity of 40% to 65% (and containing at least 80% of repeating units derived from propylene monomer) to a depth of from 50% to 75% of its maximum thickness with at least 4 and not more than 600 uniform raised embossments per square inch each embossment being enclosed by a raised lip, and the valley areas separating individual embossments constituting from 20% to 40% of the surface of the embossed film and subjecting the thus embossed film to a biaxial draw of from 2À5 times to 5À0 times in both the longitudinal and lateral directions.</p> |
