GB1310060A - Nylon panels - Google Patents

Abstract

1310060 Foamed nylon panels IMPERIAL CHEMICAL INDUSTRIES Ltd 23 Dec 1970 [16 Jan 1970] 60437/70 Divided out of 1300722 Heading C3C A nylon panel of thickness 2À5 to 25 mm., with an average density of 0À2 to 0À9 gm. per c.c. and an impact strength (S) in Joules to the weight per unit area (W) in gm. per square cm. being such that (log 10 S)/W > 2, comprises a core of a composition containing foamed "nylon material" integral with a non-porous skin of "nylon material" in which the foam has an average pore diameter of less than 1À5 mm. and is free from pores greater than 3 mm. in diameter and the skin is from 0-2 to 3 mm. thick. By "nylon material" is meant thermoplastic polymers of M.Wt. above 10,000 and Viscat softening point 150‹ to 300‹ obtained essentially by the condensation of diamines with dicarboxylic acids and/or self-condensation of amino acids or lactams wherein the polymers contain units of the formulµ -NH-R-NH-CO-R<SP>1</SP>-CO- and/or -CO-R<SP>11</SP>-NH-, where R and R<SP>1</SP> may be straight or branched chain alkylene radicals of 4 to 13 carbon atoms, m- or pphenylene radicals or 1,4-cyclohexylene radicals or additionally R<SP>1</SP> may represent a direct linkage, and R<SP>11</SP> may represent a straight chain alkylene radical of 3 to 5 carbon atoms or a 1,4- cyclohexylene radical. Specified "nylon materials" are (1) a copolymer from hexamethylene diamine adipate and hexamethylene diamine isophthalate, nylon 6 (polycaprolactam), nylon 6.12 (polyhexamethylenedodecandiamide), nylon 6.6 (polyhexamethyleneadipamide), nylon 6.10 (polyhexamethylenedecandiamide) and nylon 6.6/6/6.10 (a copolymer from hexamethylenediamine adipate caprolactam and hexamethylenediamine decandoic acid salt). The skin and core may be different nylons. The "nylon material" may be mixed with pigments, fillers, fibres such as of glass, plasticizers, mould release agents, and surface active agents which preserve the fine dispersion of gas bubbles arising from the blowing agent during transition to a rigid foam. The panels are made by injecting into a panel forming cavity mould of adjustable thickness a sufficient amount of nylon material to form the desired skin and before the central portion of the material has set injecting into this material, a charge of nylon material and particular blowing agents and adjusting the mould so that the nylon material and foamable nylon material fill the mould before any foaming occurs despite the foamable material being at a temperature at or above the activating temperature of the blowing agent and thereafter enlarge the mould to the desired thickness, permit the material to foam and fill the enlarged mould and allow the materials in the mould to set. An extensive list of blowing agents is given in the Specification. Those exemplified are orthophosphoric acid and sodium oxalate, poly-(ethylene oxalate), and imidazole-4,5-dicarboxylic acid. The panels may be used as, or form part of trays, boxes, tanks, articles of furniture, interior car trims and car body panels.