Patent GB-664837-A (GB)
Title: Improvements in or relating to transfers
IPC: B44C1/175
Filed: 1948-10-09
Abstract: 664,837. Transfers; transferring designs. STEVENS, A. H. (Meyercord Co.). Oct. 9, 1948, No. 26372/48. Class 100 (ii). A transfer contains a vitrifiable material, and has a film or layer comprising two immiscible materials, each of said two materials being divided into minute, individual particles, the particles of one material being interspaced with the particles of the other material. A transfer comprises an absorbent paper backing 10, a coating of water-soluble chemically pure hydrolised starch 11, a design film 12 applied by screen printing, lithography, rotagravure or the like and comprising a pure resinous varnish and pulverised glass of desired colour mixed with or dusted on the varnish, and a carrier layer 13 comprising two immiscible materials, as ethyl cellulose and a polymethacrylate resin. The layer 13 may comprise 124 oz. ethyl cellulose in a paste with dry alcohol, with 4 oz. polymerised methyl-methacrylate resin added, all dissolved in butyl alcohol. The immiscible materials penetrate also into the design film and open it up, rendering it heterogeneous to allow easy passage of gases during firing, to avoid blisters and the like. To apply the transfer, it is dipped in water, the backing removed, a mixture of plasticiser and solvent applied to the outer surface of carrier layer 13, and the layer 12 applied to the article, adhering by means of a remainder of the starch. The transfer is then rubbed against the glass or ceramic article by a soft rubber squeegee, and the article is fired, when only the glass remains, incorporated in the article. For a glass article, firing is done at 1030-1200‹ F. and for chinaware 1250-1650‹ F., for 1¢-2 hours. The transfers may be mounted in a stack of a hundred, secured along one edge by adhesive, and the stack is dipped in water, when each transfer can be torn off ready to remove the backing. A liquid coating of the two immiscible substances may be applied to the vitreous design layer of existing transfers, and renders them heterogeneous. Alternatively, a duplex transfer may be used, comprising a heavy paper backing, a layer of adhesive, a layer of thin tissue paper, and the starch, design and carrier layers. In use, the tissue paper is stripped from the backing, or they may be used in unified stacks of a hundred, being immersed in water treated with a wetting agent causing the tissue'paper to adhere to the backing, so that the layers 12 and 13 can be removed from the tissue paper. In another form, the material or ink used to print the design film is composed of pulverised glass and colouring material, added to a binder containing solvents and the two immiscible materials, and the transfer applied as before, the mixture of plasticiser and solvent comprising equal parts of dibutylphthalate diethylene glycol and alcohol. In one specific embodiment of vitrifiable ink composition used in forming the design layer, a lead borosilicate base or flux comprising 70 per cent lead oxide, 15 per cent silica and 15 per cent boric oxide is mixed and finely ground with colouring metallic oxides, such as cadmium sulphoselenide and cadmium oxide (red), cadmium sulphide (yellow), chromium, iron and cobalt oxide (black), chromium, cobalt, antimony and sometimes tin oxide (green), lead molybdate or titanium dioxide (white), lead molybdate and a little cadmium sulphoselenide (pink), or chromium, iron and zinc oxide (brown), in the ratio of 100 parts of flux to 12-20 parts of colouring matter. This mixture is mixed with a flowable vehicle comprising 60 per cent of the substance known under the Registered Trade Mark " Cellosolve " (butyl), 19 per cent polymerized methyl-methacrylate resin, 19 per cent chlorinated biphenyl, 2 per cent lecithin, in the ratio of 4.75 parts of mixture to 1 part of nowable vehicles. Now is added 15 per cent by volume ethyl cellulose, and 15 per cent by volume finely ground clear flint glass. The protective coating or carrier layer comprises clear ethyl cellulose in a solvent, and is larger than the design layer to protect its edges. In either form, a cellulose ether such as benzyl cellulose, and other types of polymerised acrylic-resins may be used instead of ethyl cellulose and a polymethacrylate resin respectively.