Patent ID: 8097113

Claim:
A process comprising sequentially: (a) providing a rigid layer and a poly (vinyl acetal) interlayer, (b) constructing a sub-assembly comprising the rigid layer and poly (vinyl acetal) interlayer; (c) placing the sub-assembly in a vacuum bag or vacuum press; (d) applying a vacuum to the vacuum bag or vacuum press for a maximum of 30 minutes, wherein the sub-assembly is maintained at a temperature between 10° C. and 22° C.; (e) increasing the temperature of the sub-assembly to at least 125° C. over a minimum of 20 minutes, while maintaining vacuum on the vacuum bag; (f) processing the sub-assembly at minimum of 125° C. for a minimum of 20 minutes to form a laminate; (g) cooling the laminate at a rate of at least 0.5° C./minute until the laminate reaches a temperature below 40° C.; (h) removing the vacuum from the vacuum bag, containing the laminate, and allowing the laminate to reach atmospheric pressure as the laminate continues to cool to ambient temperature; wherein step (a) through step (d) are carried out at 10° C. to 22° C. and less than 40 percent relative humidity; and step (d) through step (g) are carried out under a vacuum pressure applied of 40 kPa or less.