| 摘要 |
1,273,706. Foam filled extruded section. FARBENFABRIKEN BAYER A.G. 20 Nov., 1970 [27 Nov., 1969], No. 55271/70. Heading B5A. [Also in Division C3] A foamable plastics liquid reaction mixture 15 is introduced, from a cooling chamber 9 and via an axially adjustable tube 10 (which may comprise an internal former), to foam as a core within an extruded tubular thermoplastics covering 3 at a location, downstream of the tube extrusion die outlet 2, at which the covering has been cooled by a sizing die 4 (comprising a cooling jacket 5 and suction chamber 6) to a temperature not greater than 100‹ C., and preferably of 20‹ to 50‹ C. The tube 10 is provided with seals 12, 13, the latter to prevent reverse flow of the mixture. It is stated that the extruded tube into which the foam is introduced may be supported by internal compressed air pressure. The process produces a higher density outer zone 16 of the core, e.g. 1.2 gm./c.c., than of its interior, e.g. 0.3 or 0.4 gm./c.c. The covering may comprise polyethylene, polypropylene, polyvinyl or polyvinylidene chloride, polystyrene, polycarbonate, and polyamide. The core may be based on polyurethane, unsaturated polyesters, epoxide resins, and #-caprolactam, as well as their copolymers. In one example, the thermoplastics covering comprises a tube of polystyrene, acrylonitrile - butadiene - styrene polymer, or polyamide, and the reaction mixture comprises a polyurethane comprising specified proportions of two components; (A), polyether of ammonia and propylene oxide, polyether or trimethylolpropane and hexane @riol reacted with propylene oxide and ethylene oxide, 1,4- butane diol, trichloromonofluoromethane, permethylated diethylene triamine, polysiloxane polyalkylene glycolether; and (B), carbodiimide - modified diphenylmethane - 4,41 - diisocyanate, yielding a solid zone 16 of 1.2g./c.c. In another example, the covering comprises a low-pressure polyethylene box section, and the core comprises components; (A), unsaturated polyester, Na-salt of sulphonated ricinoleic acid, bis - (dimethylethylamino)- methylamine, dimethyl polysiloxane; and (B), methylethylketone; and (C) 4,4<SP>1</SP>-diphenylmethane diisocyanate, yielding a solid zone 16 of 1.1 gm./c.c. which falls to 0.37 at the core centre. |
