Patent GB-1187681-A (GB)
Title: Wood Grain Sheet Material
IPC: C09J7/29
Filed: 1967-03-09
Abstract: 1,187,681. Ornamenting. MINNESOTA MINING & MFG. CO. 9 March, 1967 [9 March, 1966], No. 11075/67. Heading B6G. [Also in Division B2] A simulated wood grain sheet material suitable as a trim decoration for automobiles comprises a base laminate structure 10, a normally tacky pressure sensitive adhesive coating 11, and a disposable removable protective liner 12 temporarily adhered over the adhesive coating. The base laminate structure is between 75 and 375 microns thick and comprises the following layers: a flexible, opaque, pigmented layer 15 of plasticized polyvinyl chloride resin, 25 microns plus or minus 10 microns in thickness and which softens at above 70 C; a layer of differently pigmented inks printed in a wood grain pattern at a thickness no greater than 5 microns; a flexible, transparent, protective layer 17 of plasticized polyvinyl chloride resin of thickness 50-300 microns, embossed with a tick pattern on the surface consisting of randomly positioned line-like depressions aligned with the wood grain pattern and being at least 25 microns deep but no deeper than three quarters of the thickness of the protective layer, no more than 12 mm. long, no wider than twice their depth, and simulating the tick pattern of natural wood; an outer, hard, non-tacky, acrylate resin, transparent layer 18 which softens at above 60 C, containing u.v. absorbers and being between 10 and 25 microns thick, resistant to discolouration, and a protector against degradation by weathering, and uniformly thick over all surfaces of the protective layer so that the exterior exposed surface of the transparent layer exhibits a replication of the tick pattern. A prime coating such as an insitu chemically-reacted film may be present, up to 5 microns thick, between the wood grain pattern and the bodying layer. In one embodiment the pigmented layer is first coated on to a low adhesion sized paper surface and comprises a terpolymer of 91% vinylchloride, 3% vinylacetate, 5.7% vinylalcohol having a softening point at 82 to 100 Centigrade, a liquid polymeric epoxidized soybean oil as plasticizer, organic tin chelate and alkyl-aryl phosphite as stabilizers, titanium dioxide, chromium oxide, red iron oxide and carbon black pigment, and dispersant dissolved in a solvent mixture and cast with a roll coater. The layer is dried at 160 Centrigade. A wood grain pattern is printed from a rotogravure press on the pigmented layer using a composition having the basic ingredients of the pigmented composition. The protective layer suitably consisting of the ingredients of the pigmented layer excluding all pigment is preformed and a size coating of an adhesive composition comprising a polyester resin containing hydroxyl groups available for isocyanate reaction and liquid polymethylene polyphenyl isocyanate in a solvent applied by a rotogravure cylinder. The size side of the protective layer is laminated to the printed wood grain surface of the pigmented layer by passing the layers through pressure roll heated to 110 to 130 C. The tick pattern is then applied by passing the laminate, preheated to 220 to 235 C., through a cylindrical nip. The cylinder carries the pattern of projections which form the tick marks. A transparent lacquer coating of polyethyl methacrylate, epoxidized soybean oil plasticizer, 2,2-dihydroxy 4,4-dimethoxy benzophenone as u.v. absorber and solvent is applied to the exposed surface of the protective layer by means of a roll coater. Silica fines may be added to the lacquer to reduce gloss. The low adhesion sized paper is then removed. A pressure sensitive adhesive comprising a copolymer of fusel oil acrylate and acrylic acid is applied to a temporary liner consisting of clay sized kraft paper coated with a non-migrating release silicone or p.t.f.e. coating. The adhesive coated liner is then laminated to the base laminate structure. The wood grain sheet material can be applied as a decorative panel to automobiles by pressure lamination thereto.