Patent GB-1175692-A (GB)
Title: Tyre Sidewall Facings
IPC: B29C65/00
Filed: 1966-11-04
Abstract: 1,175,692. Reflective coating. MINNESOTA MINING & MFG. CO. 4 Nov., 1966 [5 Nov., 1965; 10 Oct., 1966], No. 49663/66. Heading B2E. [Also in Divisions B7, C3, El and G2] A reflex-reflective surface that may be applied to tyre sidewalls for decoration or warning comprises an elastomeric sheet, which may be in two layers, 25 and 26, in the external surface of which glass reflex-reflective elements 30 are embedded. In one embodiment a poly (tetramethyleneoxide) diamine-epoxy elastomeric material 26 is bar-coated onto siliconetreated release paper, and a part of the solvent evaporated off. Reflex-reflective elements 30, treated with a fluorocarbon sizing, are cascaded onto the surface, the excess shaken off, and the web passed through rubber nip rollers, after which it is heated to drive off the remaining solvent, the elements then being embedded to an average depth of 60% of their diameter. The reflective side of the web is coated with silicone rubber to form a temporary protective layer 29, and the web is again heated to cure this layer. A layer of neoprene rubber 25 is bar-coated to silicone-treated release paper 28, the paper is stripped from the diamine-epoxy material and the bared surfaces of this material and the neoprene rubber laminated together. The web thus produced is passed between nip rollers and cut into desired shapes. Completion of the natural curing of the diamine-epoxy material forms a strong bond with the neoprene rubber. In a second embodiment, the glass elements are beads which are embedded in a layer of heated polyethylene on a paper liner, and a layer of aluminium is vapourdeposited onto their exposed surfaces to make them reflex-reflective. The diamine-epoxy elastomeric layer 26 is bar-coated over the aluminium and partially cured. Neoprene rubber 25 is coated onto this web, the solvent being then driven off, and a removable layer of polyethylene film 28 is laminated thereto. The original polyethylene-coated paper layer is finally peeled away. A third embodiment comprises the steps of coating silicone-treated paper with neoprene rubber, partially drying the rubber, adding a coat of diamine-epoxy material onto which are then cascaded aluminiumvapour-coated glass beads, heat-curing the web thus formed, and etching away the exposed aluminium with sodium hydroxide solution. A temporary protective layer is finally added by pouring silicone rubber onto a non-woven rayon fibre scrim laid over the beaded surface and curing. The fourth embodiment comprises a cover sheet 29 of paper with a layer of silicone rubber cast thereon. Sized elements 30 are cascaded onto the rubber, and the web is curved. A mixture of styrene-butadiene copolymer and diamine-epoxy material is coated over the elements, solvents then being driven off, and the web being partially cured by heating. The coated materials may be applied to tyre sidewalls at the point of sale, using neoprenephenolic cement, or they may be bonded into the sidewalls by the normal process of vulcanisation during the manufacture of the tyre, the protective covering layer being peeled away after application.