| 摘要 |
1,125,477. Foamed sheets; flattened tubes; laminating. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 27 Oct., 1966 [29 Oct., 1965], No. 48254/66. Headings B5A and B5N. Foamed plastics sheets, e.g. of polystyrene are produced by passing an extruded foamed tube while its inner face is still in a hot-plasticized condition between flattening means whereby the tube is flattened and opposed sections thereof are fused together. Preferably, air pressure is maintained inside the tube so that the diameter of the completely foamed tube is further increased by 10-100%. The inner face may be additionally heated before flattening. Covering layers, e.g. of craft paper, may be passed between the flattening means and tube so as to bond the layers to the tube, preferably by heating the tube surface to melting-point, e.g. by using heated flattening means, or by heating before passing the tube through the flattening means. The tube may also be profiled simultaneously with or subsequently to the flattening thereof. The sheet produced may have a thickness of 5-200 mm. |
