Patent GB-1412211-A (GB)
Title: Floor tile and the production thereof
IPC: E04F15/10
Filed: 1973-01-02
Abstract: 1412211 Asbestos-containing floor tiles GAF CORP 2 Jan 1973 [3 Jan 1972 (2)] 271/73 Heading B2E A process for making a floor tile comprises: (a) mixing asbestos fibre, filler(s), vinyl chloride copolymer, plasticiser, pigment and light and heat stabiliser(s) to form a uniform mix at a temperature of 280 to 320‹F; or (a') mixing binder(s) based on asphalt and/or synthetic resin other than vinyl chloride copolymer, and/ or oil, together with asbestos, filler(s), antioxidant(s) and pigment(s) to form a uniform mix at 225 to 250‹F; (b) calendering the mix from step (a) to form a continuous vinyl asbestos sheet 1/16" to #" thick or calendering the mix from step (a') to form a continuous asbestos sheet 3/32" to #" thick, either continuous sheet being discharged at 150 to 185‹F and at a travel rate of at least 80 ft/min; (c) coating either sheet with a liquid composition containing a U.V. polymerisable ethylenically unsaturated polymer and/or monomer; (d) exposing the sheet travelling at 80 ft/min immediately to U.V. light having wavelengths in the range 2500Š to 4000Š in a non-oxidising atmosphere at 110 to 180‹F to cure or polymerise the coating with an exposure of 0.2 to 15 seconds to form a clear coating 0.001" to 0.005" thick; and (e) cutting the sheet into tiles at a temperature not less than 110‹F. Either sheet when discharged from the calender, may be embossed or valley printed before coating. Preferred curable coating compositions are "solventless", and may be applied by roll, spray, curtain or extrusion coating. The coating composition is preferably an acrylic-modified polyester such as acrylic, methacrylic or itaconic esters of polyhydric alcohols such as alkylene glycolsl, trimethylolethane or trimethylol propane. Telomers of diacryl polyesters and glycidyl esters with an unsaturated aliphatic carboxylic acid or linear polyesters of such acids are also mentioned, as are polyesters of maleic or fumaric acid optionally mixed with adipic or phthalic acid, with alkalene glycol or hexane 1, 6 diol. A mixture of an unsaturated alkyd resin with a telomerised ester oligomer can be used, or the oligomer can be used alone. Polymers of polyhydric alcohols with acrylic acid and an α-unsaturated, α, /3-unsaturated or saturated dicarboxylic acid are also useful, such acids including maleic, succinic, azelaic and adipic, and glycerine and sorbitol being examples of alcohols. The coating composition preferably contains a low vapour pressure vinyl monomer such as styrene butyl acrylate, vinyl toluene, or butyl or lauryl methacrylate. A typical vinyl asbestos base contains 18% asbestos fibre, 17% vinyl chloride/vinyl acetate copolymer (86;14), 5.5% plasticiser, 55% 200 mesh (U.S.) limestone filler, 3% TiO 2  pigment, and 1.5% stabilisers, and is coated with U.V. cured glycerine diacrylate maleate. A further typical base contains 5.0% limed tall oil, 10.5% coumarone-indene resin, 3.0% mineral oil and 5% polystyrene as binders, 23.0% asbestos fibre, 50.0% limestone filler, 0.5% antioxidant and 3.0% TiO 2  pigment, and is coated with U.V. cured glycerine diacrylate maleate. In a further embodiment each typical base is coated with a composition consisting of glycerine diacrylate maleate with butyl methacrylate and a photoinitiator. Further binders mentioned for the tile from step (a') are blown alsphalt and polyolefins. Flatting agents (e.g. SiO 2 ) may be added to the coating composition.