Method of pressing a curved laminated glass assembly

摘要

823,252. Laminating curved glass. PITTSBURGH PLATE GLASS CO. June 29, 1956 [Aug. 19, 1955], No. 20192/56. Drawings to Specification. Class 140. A curved laminated glass assembly comprising two matched sheets of curved glass and a thermoplastic interlayer, e.g. polyvinyl butyral, is pressed by placing the assembly in a chamber, evacuating the chamber, heating the assembly in the evacuated chamber to an elevated temperature, releasing the vacuum while maintaining the assembly at an elevated temperature, adding a gas to the chamber to provide an elevated pressure of at least 100 lb/in.2, maintaining the assembly at an elevated temperature in the chamber at an elevated pressure for a sufficient period of time to seal the interlayer to the glass sheets substantially throughout the entire area of the laminated assembly, and cooling the chamber while maintaining the elevated pressure until the bonded laminated glass assembly is cooled to a maximum temperature of about 175‹ F., whereafter the pressure may be released and the bonded assembly removed from the chamber. The elevated temperature may be between 190‹ and 350‹ F., preferably between 225‹ and 300‹ F. The gas added to the chamber may be air or steam and may be at a pressure between 100 and 250 lb/in.2, preferably between 175 and 225 lb/in.2. A gas may be bled into the chamber whilst it is evacuated, and this gas may be air or steam. When steam is bled into the chamber, the assembly is heated to at least 150‹ F. before beginning the bleed. The vacuum in the chamber during the evacuation stage may be at least 10 inches of mercury gauge, preferably 15 inches of mercury gauge. Apparatus for carrying out the method is described. Reference has been directed by the Comptroller to Specification 755,809.