High rigidity interlayers and light weight laminated multiple layer panels

Abstract

This disclosure is related to the field of polymer interlayers for multiple layer panels and multiple layer panels having at least one polymer interlayer sheet. Specifically, this disclosure is related to the field of high rigidity interlayers and light weight laminated multiple layer panels incorporating high rigidity interlayers.

We claim: 
     
         1 . A multi-layer interlayer comprising:
 a first plasticized stiff polymer layer;   a second plasticized stiff polymer layer in contact with said plasticized soft polymer layer;   a plasticized soft polymer layer in contact with said first plasticized stiff polymer layer and said second plasticized stiff polymer layer;   
       wherein at least one of the stiff polymer layers has a plasticizer content of less than or equal to about 35 phr, wherein the soft polymer layer has a plasticizer content of greater than or equal to about 48 phr, and, 
       wherein at least one of the stiff polymer layers has a glass transition temperature of greater than 33° C. 
     
     
         2 . The multi-layer interlayer of  claim 1 , wherein at least one of the stiff polymer layers has a plasticizer content of less than or equal to about 30 phr. 
     
     
         3 . The multi-layer interlayer of  claim 1 , wherein at least one of the stiff polymer layers has a plasticizer content of less than or equal to about 28 phr. 
     
     
         4 . The multi-layer interlayer of  claim 1 , wherein the plasticizer content in the first stiff polymer layer is different from the plasticizer content in the second stiff polymer layer. 
     
     
         5 . The multi-layer interlayer of  claim 1 , wherein the first stiff polymer layer and second stiff polymer layer have a glass transition temperature of greater than 33° C. 
     
     
         6 . The multi-layer interlayer of  claim 1 , wherein the amount of plasticizer in the soft polymer layer is at least 13 phr greater than the amount of plasticizer in the stiff polymer layers. 
     
     
         7 . The multi-layer interlayer of  claim 1 , wherein the amount of plasticizer in the soft polymer layer is at least 20 phr greater than the amount of plasticizer in the stiff polymer layers. 
     
     
         8 . The multi-layer interlayer of  claim 1 , wherein the amount of plasticizer in the soft polymer layer is at least 25 phr greater than the amount of plasticizer in the stiff polymer layers. 
     
     
         9 . The multi-layer interlayer of  claim 1 , wherein the soft polymer layer has a glass transition temperature of less than 15° C. 
     
     
         10 . The multi-layer interlayer of  claim 1 , wherein the soft polymer layer has a glass transition temperature of less than 5° C. 
     
     
         11 . The multi-layer interlayer of  claim 1 , wherein the soft polymer layer has a glass transition temperature of less than 0° C. 
     
     
         12 . A multi-layer interlayer comprising:
 a stiff polymer layer comprising plasticized poly(vinyl butyral);   a soft polymer layer comprising plasticized poly(vinyl butyral) in contact with said stiff polymer layer;   wherein the residual hydroxyl content in the soft polymer layer is at least 3 wt. % lower than the residual hydroxyl content in the stiff polymer layer; and   wherein the stiff polymer layers has a glass transition temperature of greater than 33° C.   
     
     
         13 . The multi-layer interlayer of  claim 12 , wherein the residual hydroxyl content in the second polymer layer at least 6 wt. % lower than the residual hydroxyl content in the first polymer. 
     
     
         14 . The multi-layer interlayer of  claim 1 , wherein the residual hydroxyl content in the second polymer layer at least 9 wt. % lower than the residual hydroxyl content in the first polymer. 
     
     
         15 . The multi-layer interlayer of  claim 12 , wherein said multi-layer interlayer comprises a second stiff polymer layer comprising plasticized poly(vinyl butyral) in contact with said soft polymer layer, and wherein said soft polymer layer is between said two stiff polymer layers. 
     
     
         16 . A multi-layer interlayer comprising:
 a first polymer layer comprising plasticized poly(vinyl butyral) and having a residual hydroxyl content of greater than or equal to 19 weight percent and a plasticizer content of less than or equal to about 35 phr, and   a second polymer layer comprising plasticized poly(vinyl butyral) and having a residual hydroxyl content of less than or equal to 16 weight percent and a plasticizer content of less than or equal to about 48 phr, wherein said second polymer layer is in contact with said first polymer layer; and   wherein at least one of the stiff polymer layers has a glass transition temperature of greater than 33° C.   
     
     
         17 . The multi-layer interlayer of  claim 16 , wherein the residual hydroxyl content in the first polymer layer is greater than 20 wt. %. 
     
     
         18 . The multi-layer interlayer of  claim 16 , wherein the residual hydroxyl content in the first polymer layer is greater than 21 wt. %. 
     
     
         19 . The multi-layer interlayer of  claim 16 , wherein the soft polymer layer has a residual hydroxyl content of less than or equal to 12 wt. %. 
     
     
         20 . The multi-layer interlayer of  claim 16 , wherein the soft polymer layer has a residual hydroxyl content of less than or equal to 10 wt. %.