| 摘要 |
1,110,287. Extruding foamed corrugated sheets and tubes. MONSANTO CHEMICALS Ltd. 17 June, 1966 [22 July, 1965], No. 31261/ 65. Heading B5A and B5N. [Also in Divisions A4 and F2] A sheet or tube corrugated over part or all of its width or circumference respectively and made of a foamed aliphatic thermoplastic resin is produced by extrusion through a die whose extrusion slot 6 is bounded by fluted lips 7, 9, the flutes 12 in one lip being offset with respect to those in the other lip. With this arrangement the corrugations are formed parallel to the direction of extrusion and the preferred thickness t, Fig. 2, is between 0À05-0À25 inch and preferably d and w are 3 to 5 times t. Other lip shapes are described, Figs 6-9 (not shown), and a take-off mechanism may comprise a roller or conveyer belt, or the extrudate may be supported by a plate perhaps associated with a second plate such that the passageway thereby formed converges downstream. The product has a preferred density in the range 2-3 1bs./ft.<SP>3</SP> and is intended primarily for packaging, upholstery or thermal insulation purposes or as a carpet underlay, and in particular may be laminated on one or both sides with, e.g. paper, cloth, metal (aluminium foil), or a film or sheet of foamed or otherwise thermoplastic resin (polyolefin). The product may be laminated with itself e.g. by folding and glueing a sheet one or more times, or with like material and in any case it is preferred in this case that the extrusion directions of adjacent layers be at an angle to one another. Specific resins mentioned are polyethylene, polypropylene, acrylonitrile, vinyl or vinylidene chloride, vinyl acetate, ethyl acrylate or methyl methacrylate and copolymers such as ethylene - vinyl acetate copolymer. Various blowing and nucleating agents are mentioned and a detailed example is given. |
