| 摘要 |
1,142,494. Extruding foamed corrugated sheets. MONSANTO CHEMICALS Ltd. 14 July, 1967 [30 Aug., 1966], No. 38556/66. Addition to 1,110,287. Heading B5A. [Also in Division A4] Foamable thermoplastic synthetic resin is extruded through a slit orifice 6, initiation of foaming occurring as the resin passes between rollers 8, 9 so that expansion thereof is between and around teeth 12. The rollers are rotated as shown, the teeth at any instant lying in the plane through axes 10, 11 being offset with respect to one another, see also Fig. 4 (not reproduced). The consequent product is a modification of that described in Specification 1,110,287, being a foamed extruded sheet having not only corrugations which are parallel to the direction of extrusion, but also a superimposed wave pattern along the length of the corrugations, see Fig. 1. Rollers 8, 9 may be replaced by one or two pairs of comb-shaped members reciprocated across and immediately downstream of orifice 6. The extrudate is supported until cool by a roller or endless belt or is passed over or between flat plates. The product may be used for packaging, in upholstery, as thermal insulation or as an underlay. Among various resins mentioned are polyethylene, polystyrene, copolymers of ethylene and vinyl acetate and graft styrene-butadiene copolymers. Numerous blowing and nucleating agents are listed, together with typical dimensions. An example is given. |
