| 摘要 |
<p>1,168,541. Laminates; sealing non-metallic sheet material. CONTINENTAL CAN CO. Inc. 9 Jan., 1967 [28 Jan., 1966], No. 1189/67. Headings B5K and B5N. A flexible package comprises untreated plies of at least two different plastics films, each of the films comprising at least one polyolefin, and having at least one heat-seal between the films prepared at sealing temperatures in excess of 250‹ F. and being separable at the original interface with a peel strength in excess of 400 grams per inch of seal width. The temperature is preferably in the range of 275‹ F.-475‹ F. and is applied at a pressure of 5-100 p.s.i. for several seconds. The films, which are internally plasticized, comprise homopolymers and copolymers of olefins and blends containing both homo- and copolymers of olefins. The plies may consist of laminates of the films on web materials such as further thermoplastic films, paper and metallic foil. The heat seal may be between films of polypropylene or an ethylene-propylene copolymer and films of a polymeric blend of polyisobutylene and an ethylene-butene copolymer. The seal may also be made between films of polyethylene and films prepared from an ionic copolymer obtained by the reaction of ethylene and ethylenically unsaturated monocarboxylic acid wherein at least 10% of the carboxylic acid groups are neutralized with an alkali metal ion.</p> |
