| 摘要 |
1,095,479. Laminates. METAL CONTAINERS Ltd. March 2, 1965 [March 3, 1964], No. 8966/64. Heading B5N. Laminates of thermoplastic films, e.g. of nylon, polyethylene terephthalate, polythene, polypropylene or polyvinylidene chloride, comprise at least two plies uniaxially oriented in directions which intersect in adjacent layers the plies being line- or spot-welded together and also weakly adhered together between the welds by material which may comprise a solution in toluene or xylene of low molecular weight (5000-10,000) polythene or of aluminium stearate or animal or vegetable oil. The welding may be effected by heat, ultrasonic action, or by applying a solvent for the film or a polymerizable adhesive. At least one of the plies may be formed with internal microscopic cracks or cavities, as by dispersing therein, before or after orientation, a volatile or gas-forming agent subsequently volatilized or dispersed. The laminate may comprise three films of which that in the centre is longitudinally oriented, the outer films being oriented oppositely at 60 degrees. In an example two crystalline highdensity polythenefilms, oppositely oriented at 60 degrees, have applied to them in stripes, as by printing rollers, a cooled 10% solution of 1000 M.W. polythene in hot toluene, and are subsequently laminated together between rollers by blowing toluene vapour on to them in quantity sufficient to dissolve the surface of the films between the stripes. The invention is stated to improve the tear-strength of the laminates and to provide heavy-duty products suitable for bags, tarpaulins &c. |
