Patent GB-968991-A (GB)
Title: Improvements in decorative plastic surface covering and process therefor
IPC: D06N7/00
Filed: 1960-09-21
Abstract: 968,991. Coated sheet materials. MICHAEL NAIRN & CO. Ltd. Sept. 21, 1960 [Sept. 21, 1959], No. 29842/60. Heading B2E. A resilient decorative surface covering comprises a flexible sheet having in one surface thereof a plurality of areas depressed below the said surface, a layer of expanded and foamed plasticized thermoplastic resinous composition and a solid plasticized thermoplastic resinous composition bonded to the foamed surface, the product having a plurality of raised portions on its surface conforming in character and spacing to the depressed areas in the flexible sheet. The covering may be produced by coating one surface of a flexible sheet which contains depressed areas in its surface with a thermoplastic resinous composition containing an effective amount of foaming agent, applying a second coating which does not contain any foaming agent to the foamable coating, heating the coatings to fuse the resins and to decompose the foaming agent thereby creating a textured decorative surface bearing a plurality of raised areas which conform in shape and position to the depressed areas in the surface of the flexible sheet and having a solid resinous surface formed by the second coating. The foamable thermoplastic resinous composition may have a viscosity, measured with a Brookfield viscometer using a No. 6 spindle at 10 r.p.m. at 25 ‹C.. of between 200 and 25.000 centipoises. The foam layer and the solid layer may comprise a vinyl resin which may have a specific viscosity determined by timing the flow of a solution of the resin in nitrobenzene at 20 ‹C. of between 0À17 and 0À31, e.g. a vinyl chloride polymer, comprising 50-150 parts by weight nlasticizer per 100 parts by weight vinyl resin. The ratio by weight of plasticizer to resin may be 0À5-1À5:1 The coating compositions may fuse at approximately the same temperature. The foam layer may be from 0À10-0À15 inch thick and the second coating may have a thickness of between 2 and 8 mils. The foaming agent may have a minimum initial decomposition temperature of at least 200 ‹F. and is substantially completely decomposed at a temperature below 450 ‹F. The foamable composition may be heated before application of the second coating to gel the composition without decomposing the foaming agent. The depressed areas may have a depth of at least 5 mils, e.g. 0À015-0À030 inch. The flexible sheet, which may be fibrous or non-fibrous and may be impregnated, may be stripped from the foamed product. As shown, a sheet of felted fibrous backing 11 is embossed by roll 12, a uniform layer of resinous composition 19, which fills the depressions of the embossed felt 15, is applied by means of doctor blade 18. The coated felt is engaged by pins 25 of endless belt 22 and passed through oven 30 where composition 19 is gelled but not foamed, prior to passing through cooling chamber 33, and then to printing apparatus 40 which applies a uniform print coating 45, 46 on the first coating. The printed sheet passes through oven 51 to fuse and foam composition 19 to form foamed layer 53, prior to passage through cooler 55. Examples of backing sheets, impregnants, foamable and solid coating compositions are given. Specification 939,789 is referred to.