Patent GB-1163962-A (GB)
Title: Improvements in or relating to the Production of Covering Materials
IPC: D06N7/00
Filed: 1966-07-20
Abstract: 1,163,962. Foamed coating. GAF CORP. 20 July, 1966 [21 July, 1965; 6 June, 1966], No. 32694/66. Heading B2E. A decorative covering material is produced by applying to and distributing over a base a foamable mixture of liquid polyvinyl chloride resin and a thermally decomposable foaming agent, and heating the mixture to fuse the resin and decompose the foaming agent, a catalyst for lowering the decomposition temperature of the foaming agent being also distributed over the base to lower the decomposition temperature of the foaming agent and an agent for suppressing the action of the catalyst is also separately applied in spaced pattern areas so that upon heating the pattern areas in which the catalyst is suppressed foam or expand to a lesser extent that in other areas of the product. In one embodiment the product simulates 9 tile structure. The tiles themselves are simulated by lands separated by a network of valleys simulating mortar joints between the tiles. The lands are made of foamed resin material of appreciable thickness as compared with the valleys. The product is built upon a flexible base sheet comprising a layer of felt, e.g. an organic felt or an asbestos felt. The pattern effects may be floral or may simulate gravel. In one embodiment, a flexible sheet such as a layer of felt is provided with a layer of liquid foamable material comprising mixture of polyvinyl chloride resin and containing in addition to plasticisers or pigments a foaming agent azodicarbonamide, zinc naphthanate as catalyst for the de-' composition of the foaming agent and also acting as stabiliser for the resin. The foamable layer is then heated sufficiently to gel the layer without decomposing the foaming agent. The material is then subjected to a printing operation, the printing composition containing a catalyst suppressing agent such as benzotriazole or aminotriazole or N-phenyl glycine. The foamable layer of printing is then completely covered with a coating of transparent polyvinyl chloride resin heated to a temperature sufficient to fuse the resin materials present and at the same time to decompose the foaming agent, the decomposition effect being pronounced in the non-suppressed areas to produce a product in which a relief effect is developed following the pattern of printing. In Figure 6 a felt web W is delivered from supply roll 11 to a coating equipment incorporating a reservoir 12 containing a coating composition and having pick-up roll 13, and another roll 14 around which the web passes in contact with the pick-up roll 13. The web passes through one or more heaters indicated at 15 which may be either the radian heat or hot air type, through an accumulator and then through another coating equipment incorporating a rubber surfaced back-up roll 16 a casting roll 17 and a metering roll 18, the latter rolls being provided with blades as indicated at 19 as an aid to establishment of a reservoir of coating material as indicated at 20 for which the foamable coating composition is delivered by roll 17 to the web. The web then passes through heating means 21 for effecting gelling of the foamable coat, then through two printing stages, e.g. of the gravure type incorporating a reservoir 22 for a printing composition, a printing roll 23 having an etched surface in combination with a doctor blade 24. A heater 25 serves to at least 'partially dry the printing composition applied. A similar arrangement is included in the second printing stage, the web then enters a reverse roll coater incorporating a back-up roll 27, pressing roll 28 and metering roll 29, together with suitable blades 30 for establishing a reservoir of coating composition as indicated at 31 to apply a transparent resin wear layer. The web is then fed to an oven 32 to decompose the foaming agent and fuse the resin materials applied to the product before finally being wound up on brake-up reel 33 after suitable cooling and after passing through an accumulator. By employing two printing stages in one of which a printing composition was transparent contain a catalyst suppressant and in the other in which the printing composition contain no catalyst suppressant but contains a pigment, a product may be obtained having both lands and valleys, at least a portion of the lands being printed in contrasting colour with the valleys or with other portions of the lands or with both. A modification of the apparatus is described and illustrated in Figure 7 not shown, wherein means for applying a smoothing coat, e.g. of polyvinyl chloride resin to the web is provided prior to the application of the foamable coat using similar equipment. Flexible base sheets mentioned are impregnated asbestos felt or a resin impregnated cellulose or other organic felt, or with suitable sealing coats an asphalt saturated organic felt for floor coverings, paper sheet, cloth or metal foil for wall coverings or upholstery. A prime coat may be applied made up of a latex containing an acrylic polymer with or without pigments or fillers, e.g. a latex of an ethyl acrylate-methyl methacrylate copolymer and clay. Resins for the foamable coat, transparent top coat, and the smoothing coat are preferably polyvinyl chloride resin as plastisols or organosols. Examples of suitable compositions for the smoothing coat, the foamable coat, are given. Examples of foaming agents, and catalysts for the decomposition of the foaming agent are given. The suppressant composition may be of the solution or dispersion type. A suitable dispersion type printing composition may be made with paste grade polyvinyl resin as a base and a solution type of ink may be made up of equal parts of a copolymer vinyl chloride of vinyl acetate and a terpolymer of vinyl chloride-vinyl acetate and maleic acid. Examples of suppressing agents are given.