| 摘要 |
923,899. Tear tapes; laminates and laminating. UNION CARBIDE CORPORATION. Aug. 28, 1959 [April 13, 1958], No. 29507/59. Class 140. A tear tape, for a polyethylene film-wrapping material having a density of from 0.91 to 0.96, comprises a backing material having an extensibility of at least 10% lower than the polyethylene film, and a synthetic thermoplastic resinous coating having a softening point below that of the backing material, the coating being heat-bondable at temperatures within the range 330‹ to 450‹ F. (166‹ to 232‹ C.) and serving to bond the backing material to the external surface of the polyethylene film. Suitable backing materials are " Cellophane " (Registered Trade Mark), polyethylene terephthalate and polycarbonate films. Coatings specified are of copolymers and homopolymers of olefins, especially of ethylene. A method of applying a tear tape to a polyethylene film 26 comprises drawing from a supply roll (3 rolls 10a, 10b and 10c shown) a tear tape 12 fabricated from a backing material possessing lower extensibility than the polythylene film having a synthetic thermoplastic resinous coating heat bondable to the polyethylene film and having a softening point below that of the backing material, passing the tape to a heating zone, softening the coating, and contacting the softened coating with the polyethylene film to form a laminate 30. The coating may be heated, e.g. over a heated bed 18, to a temperature between 330‹ and 450‹ F. immediately prior to contact with the polyethylene film. |
