| 摘要 |
1,130,318. Plastics tubes. KALLE A.G. 1 April, 1966 [2 April, 1965], No. 14542/66. Heading F2P. [Also in Division B5] Multi-layer tubes or tubular films are made by extruding a first thermoplastics material from a die head 2 over a temperature regulable mandrel 4 and extruding one or more further layers from one or more annular die heads 7 axially and adjustably spaced along mandrel 4, such that in the region of each application the already formed tube has its internal surface at a temperature below, and its external surface at a temperature above, its softening point. The formed tube may be stretched axially or bi-axially in a heating zone downstream of draw-off rollers 6, e.g. by admitting air under pressure to conduit 10 which air flows past rollers 6 through tube side portions (11), Fig. 2 (not shown). The tube diameter may vary between 10-1000 mm., each layer between 0.002-0.4 mm. and the total wall thickness between 0.01-0.8 mm. Preferably the innermost layer has the lowest softening temperature and preferred materials mentioned are polyesters, polyamides and poly-alkylenes. In specific examples, a 50Á wall thickness polycaprolactam tube is extruded onto a 50Á polyethylene tube; a tube of polyethylene terephthalate is extruded on to a 400Á thick polyethylene tube and the composite tube is stretched to have a thickness of 50Á; a 200Á polyethylene terophthalate tube is extruded on to a 200Á tube of a linear copolyester of tere-and isophthalic acids and the composite tube is stretched to have a wall thickness of 28Á; a 100Á tube of a linear copolyester of tere- and isophthalic acids is extruded on to a 250Á tube of polyethylene terephthalate and the composite tube is stretched; a stretched tube of 450Á thickness is formed from a layer of a linear copolyester of tere- and isophthalic acids on a 200Á layer of polyethylene terephthalate on a further 200Á layer of a linear copolyester of tere- and isophthalic acids. |
