| 摘要 |
1479062 Embossed films; sheet forming ETHYL CORP 17 Nov 1974 [26 Dec 1973] 50081/74 Headings B5B and B5A A thermoplastics film is embossed with a pattern of longitudinally and laterally extending rows of protuberances and depressions, 10 and 14. The protuberances are four-sided truncated pyramids with each side wall 16 having a common edge with the base of a depression, forming an angle of 95 to 135 degrees with this bottom wall 12. Each hollow protuberance is from 0À5 mils. to 10 mils. in height and forms a depression on the other film surface. The films may be made by conventional machinery, either by embossing a pre-formed film with patterned nip rolls or by casting an extruded melt on to a patterned chill roll. The thermoplastics mentioned are polyethylene, polypropylene either being with or without a filler, and ethylene-vinyl acetate copolymer. The preferred film thickness is from 0À5 to 10 mils., most preferred being from 0À5 to 2À0 mils. |
