Method of continuously providing a fastener on a thermoplastic film

摘要

1,102,970. Bags with securing means. HIGH POLYMER CHEMICAL INDUSTRIES Ltd. 6 Dec., 1965 [5 March, 1965], No. 51694/65. Heading B8K. [Also in Division B5] A thermoplastic film bag has at its mouth at least one pair of male and female fastener members which can be opened and closed freely so as to seal the contents of the bag, said fasteners being made of thermoplastic resin. The thermoplastic resin used for making the film and that used for making the fastener members may be of different chemical composition, or of different physical properties, e.g. of different colour. Specified thermoplastic resins include polyethylene (high, medium and low pressure processes), polypropylene, polystyrene, polyvinyl chloride (hard and soft), polyvinylidene chloride, cellulose acetate, polyesters (e.g. polyethylene terephthalate), and polyamides, e.g. polyhexamethylene adipamide. Fig. 2 shows an extrusion nozzle 2 suitable for the process of the invention, having a slit opening 3 for the extrusion of the film, said slit communicating with the outlet of the passage through which the resin is supplied. 41 is the extrusion orifice for the male fastener member and 51 that for the female fastener member, both 41 and 51 being separated from slit 3 by a thin portion 6. 41 and 51 communicate with the source of supply of the fastener resin. After extrusion, the film and fastener member materials are united in contact with the upper surface of a roll, or in the neighbourhood thereof. The cooling as well as the fusing together of the film and fastener members being then completed there. Examples are given.