GB800669A - Improvements in or relating to the manufacturing of safety glass - Google Patents

Abstract

800,669. Laminated glass. SOC. DU VERRE TRIPLEX. Nov. 29, 1956 [Dec. 14, 1955], No. 36565/56. Class 140. Laminated safety glass is made by stacking assemblies 15, 16, Fig. 6, of two or more glass plates and one or more thermoplastic interlayers, with sets of separators 18 such as small cylinders, cubes, or elongated rods between assemblies or groups of assemblies, heating the stack under partial vacuum until the interlayer material becomes plastic, and thereafter heating the stack under superatmospheric gaseous pressure. The glass plates may be flat or curved, the thermoplastic interlayers may be of polyvinyl butyral or plasticized cellulose acetate, and the separators may be of wood, metal or rubber. When the stack is split by the sets of separators into groups of 2 or more assemblies 15, 16, sheets of paper or cardboard 17 may be positioned between adjacent assemblies. The two heating steps may be performed in separate autoclaves, or in a single autoclave 7, Fig. 8, having an end closure 8, heaters 9, a circuit consisting of an inlet pipe 10, a heat exchanger 11, a pump 12, and an outlet pipe 13 for circulating hot air through the autoclave, and a pump 14 for adjusting the pressure within the autoclave. The stack is wheeled into the autoclave on a trolley 1 with a slatted staging or base. The top assemblies are kept under pressure by weights 6. The separating rods or bars may have the crosssection shown in Fig. 3, and may project from the stack. Specification 755,809 is referred to.