Glass laminate containing poly vinyl acetal
View Patent ↗A process comprises constructing a sub-assembly including a rigid layer and a poly (vinyl acetal) interlayer in a vacuum bag or vacuum press; applying vacuum to the vacuum bag or vacuum press for a maximum of 30 to 60 minutes while maintaining the sub-assembly at a temperature between 10° C. and 22° C. to produce a cooled sub-assembly; increasing the temperature of the cooled sub-assembly to at least 100° C. or 125° C. over a minimum of 10 minutes or 20 minutes to produce a heated sub-assembly; maintaining the heated sub-assembly at minimum of 100° C. or 125° C. for a minimum of 10 minutes or 20 minutes to form a laminate; cooling the laminate at a rate of at least 0.5° C./minute until the laminate reaches a temperature below 40° C.; contemporaneously with the cooling, removing the vacuum from the vacuum bag, containing the laminate, and allowing the laminate to reach atmospheric pressure.
1. 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.
2. The process of claim 1 wherein the poly (vinyl acetal) interlayer is a polyvinyl butyral interlayer.
3. The process of claim 1 wherein the rigid layer is a glass sheet.
4. The process of claim 1 wherein step (a) to step (d) are carried out at 10° C. to 20° C.
5. The process of claim 1 wherein step (a) to step (d) are carried out at 10° C. to 18° C.
6. The process of claim 1 wherein step (d) is carried out for 10 minutes.
7. The process of claim 1 wherein step (e) to step (f) is carried out at least 130° C.
8. The process of claim 1 wherein step (e) and step (f) are carried out at 135° C.
9. The process of claim 2 wherein the polyvinyl butyral is stored at about 6° C. to 20° C. and 20 to 40 percent relative humidity.
10. The process of claim 9 wherein the polyvinyl butyral is stored for at least 24 hours before carrying out step (b).
11. The process of claim 5 wherein step (d) is carried out at 15.5° C.