Patent GB-1234079-A (GB)
IPC: B44C3/00
Filed: 1968-05-29
Abstract: 1,234,079. Coated sheet materials. INSTITUT NATIONAL DU VERRE A.S.B.L. 29 May, 1968 [28 June, 1967], No. 25791/68. Heading B2E. An article has a surface relief pattern comprising a multiplicity of protruberances which taper towards their summits and which on one side (the same for all the protruberances) bear a coloured surface coating, the other sides being left uncoated or bearing a coating of different colour or colour density so that the two sides are different in appearance, the coloured surface coating decrasing in thickness towards the summits or around the protruberances as these are viewed in plan. The effect can be achieved by displacing the surface of the article progressively through a falling film of colour coating composition so that the latter forms a coating only or predominantly on the sides of the protruberances which face the direction of advance of the surface. A coating of different colour density or different colour may then be formed on the other sides by displacing the surface through a falling film of coloured coating composition with a surface differently oriented in respect of the film than in respect of the previous displacement. The article can be flat or curved glass or plastics sheets, tubes and hollow-ware articles patterned by means of rollers or moulds, and reliefpatterned panels and other articles made of wood. Some protruberances can be left without a coloured coating or can be coated uniformly with one and the same coating composition. The coating on the one side of each protruberance may comprise side by side zones of different colour extending in the foot-to-summit direction. The profiles of the protruberances in cross-sectional elevation may be conical, or may comprise outwardly convex or concave sides and they need not be radially symmetrical. The coating composition can be paints based on vegetable or mineral oils, varnishes, lacquers, suspensions or solutions or colouring agents in liquid media and vitrifiable enamels which may be transparent, semi-transparent or opaque. Particular articles mentioned are a sheet of rolled glass bearing a relief pattern on one surface comprising a plurality of substantially parallel prismatic portions of triangular section, a curved sheet of acrylic plastics formed with a surface relief pattern similar to that of the glass sheet, a sheet of aluminium stamped with a relief pattern formed by an assembly of cones of revolution having intersections of varying size with one another, bottles, vases. As shown in Figure 4 apparatus comprises a conveyor formed by a series of rollers 40 so driven that a sheet of rolled patterned glass 43 is displaced at high speed. Disposed above the conveyor are two reservoirs 40, 44a adapted to contain the liquids to form the coloured coatings. Each reservoir comprises two mutually inclined longitudinal walls 45, 45a, defining a slot at the bottom of the reservoir, and two end walls 46, 46a. A mobile bar 47 and a fixed bar 47a are provided to define a discharge slot 45b. The bar 47 is movable by means of regulating screws 48. The reservoirs are closed by a cover into which pipes 50, 50a discharge to supply a coating liquid. Vertical rods extend downwardly from the ends of the slot to keep the coating film at its required width by the effect of surface tension. In operation, a portion of the film 52 flowing through the slot 45b of the reservoir 44 is intercepted by the sheet glass 43. Collecting tanks disposed beneath the reservoirs collect the coating liquid which is not intercepted by the sheet, and the liquid collected in the tanks is returned by pumps to the reservoirs. The Examples relate to (1) the application of a paint comprising 12% chlorinated rubber, 7% alkyd resin, 8% boiled linseed oil, 25% zinc chromate, 10% filler, 34% white spirit, 9% solvent and viscosity 1.4 poise to one side only of the protruberances thereon; (2) the application of a paint as in 1) diluted with turpentine so that the coatings decreased in thickness towards the summits of the prismatic portions; (3) the application of semi-transparent vitrifiable enamel of composition: 47% SiO 2 , 13% Na 2 O, 5% K 2 O, 15% B 2 O 3 , 5% Al 2 O 3 , 4% F 2 , 6% CaO, 5% Sb 2 O 3 , by spraying to a vertically disposed aluminium sheet with a relief-patterned surface, and keeping the sheet in a vertical position after the spraying to allow the enamel to flow along the relief, and then spraying the sheet a second time with the sheet oriented differently.