GB1200055A - Production of patterned thermoplastic sheet material - Google Patents

Abstract

1,200,055. Laminates. DUNLOP SEMTEX Ltd. 22 Nov., 1967 [26 Nov., 1966], No. 53036/66. Addition to 1,152,036. Heading B5N. [Also in Division B2] Patterned thermoplastic sheet material is produced in a method comprising the steps of applying a pattern to one surface of a single- or multi-layered thermoplastic resin composition, at least one layer of which contains a blowing agent and is thereby expandable, adhering the other surface of the resin composition by means of an adhesive to a carrier sheet, heating to decompose the blowing agent to form a cellular layer and stripping from the carrier sheet the sheet material so formed including a layer derived from the adhesive. The thermoplastic material is preferably based on vinyl chloride resins, e.g. P.V.C., vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer. The carrier sheet is preferably an endless steel belt whilst the adhesive is preferably based on a P.V.C. plastisol composition. The expandable thermoplastic layer is produced by spreading an expandable plasticol composition, suitably based on P.V.C., on to a calendered thermoplastic sheet. The plastisol-coated sheet material may be passed beneath infra-red heaters to gel the plastisol such that a pattern may then be applied to this gelled plastisol layer. The composite structure is adhered to the carrier sheet by means of the P.V.C. plastisol adhesive composition and the composite laminate is passed through a heating oven to form the cellular layer. This heating oven may be of the infra-red or high-frequency dielectric type and may comprise two or more distinct zones in which different temperatures are maintained. A spray of cooling water may be directed against the underside of the carrier sheet when it has left the oven. In a preferred embodiment, a hardenable surfacing composition, suitably based on a P.V.C. plastisol, may be applied to the patterned surface of thee xpandable thermoplastic layer prior to the heating step. This composition is chosen to be hardenable to a clear layer which may then be conveniently embossed. The final composite structure may be laminated to a backing material at its unpatterned lowermost surface. This backing material may be a flooring felt saturated with bitumen or resin or a thermoplastic backing material based on a P.V.C. binder. This may be achieved in the former case by using an acrylic emulsion and in the latter by heat lamination. The adhesive composition may contain a plasticizer and stabilizer and the expandable layer may contain a plasticizer and pigment, the blowing agent being preferably azodicarbonamide.