| 摘要 |
<p>823,499. Laminating glass sheets. PITTSBURGH PLATE GLASS CO. Jan. 20, 1958 [Feb. 14, 1957], No. 1839/58. Class 140. In a process of making laminated assemblies of pairs of curved glass sheets for windshields &c. in which the pairs of sheets are bent simultaneously in a mould at softening temperatures and subsequently separated for the insertion of a layer of plastic such as polyvinyl butyral and then reassembled for laminating under pressure and heat, accurate registration of the sheets after reassembly is secured by applying to the inner surface of one of the sheets before moulding a pair of spaced spots of a composition which stains both sheets at the moulding temperature. As shown the spots 14 are applied close to one edge of that part 10 of the assembly which is only slightly curved and close to the wings 12 which are more sharply curved; in the finished laminate they are covered by the frame. The spots are about 0.002 inch in thickness and may comprise coloured enamel, glass frit, or paper soaked in salts such as lithium salts which produce etched markings. Preferably, however, they comprise compositions made by grinding silver chloride and copper sulphate (in proportions within the range 2: 1 and 6: 1), yellow ochre, a dispersion liquid such as alcohol and a thickener such as pine oil. Such a composition may be applied as drops or, with the addition of polyvinyl butyral, may be sprayed on to transfer paper, small moistened discs of which are applied to the glass and the paper backing remover. Alternatively a similar composition having an added wax may be applied through a metal stencil screen electrically heated to the melting point of the wax.</p> |
