Improvements in and relating to foamed polymers

摘要

A foamable thermoplastic polymer composition comprising 95 to 35% by weight of virgin foamable polymer and 5 to 65% by weight of foamed recycle polymer is extruded. Preferred polymer compositions are styrene polymers such as normal crystal grade polystyrene, high impact polystyrene and mixtures of these. Also suitable are polymers containing at least 50% by weight of styrene, cellulose ethers and esters, homopolymers and interpolymers of monomeric compounds containing the grouping, such as olefins, vinyl halides, vinyl esters of carboxylic acids, vinyl ethers, halogenated olefins, unsaturated carboxylic acids, acids and derivatives thereof, interpolymers of the above mentioned vinylidene monomers with a ,b -unsaturated polycarboxylic acids and derivatives thereof. Polycarbonates, polyoxymethylene, oxymethylene - alkylene oxide co-polymers, polyurethanes polyethylene terephthalate and nylon are also mentioned. The amount of recycle polymer in the composition can vary from 10% to 50% by weight of the total polymer. The composition can be extruded in the form of a sheet and one or both sides of the sheet can be chilled with an air blast, an air-water mist, water, nitrogen, argon or helium, to produce a foamed core integrally united to a non-porous skin. Specification 1,008,569 is referred to.