Intrusion resistant glass laminates

Abstract

Composite laminate interlayers for adhering a glass laminate comprising two sheets of polyethylene terephthalate (PET) between layers of plasticized polyvinyl butyral (PVB) adhesive layers, wherein the two PET layers provide increased stiffness for the laminate without sacrificing the optical clarity of the laminate.

I claim:  
     
         1 . A composite laminate interlayer for a glass laminate comprising: two or more sheets of bonded optical-grade polyethylene terephthalate between two layers of plasticized polyvinyl butyral.  
     
     
         2 . The interlayer of  claim 1  wherein the thickness of each polyethylene terephthalate layer is between about 0.025 mm (1 mil) and about 0.175 mm (7 mil) and the thickness of each plasticized polyvinyl butyral layer is between about 0.125 mm (5 mil) and about 2 mm (80 mil).  
     
     
         3 . The interlayer of  claim 2  wherein each polyethylene terephthalate layer has a different thickness.  
     
     
         4 . The interlayer of  claim 2  wherein each polyethylene terephthalate layer has about the same thickness.  
     
     
         5 . The interlayer of  claim 2  wherein the thickness of each polyethylene terephthalate layer is about 0.175 mm (7 mil).  
     
     
         6 . The interlayer of  claim 2  wherein the thickness of each plasticized polyvinyl butyral layer is between about 0.375 mm (15 mil) and about 1.5 mm (60 mil).  
     
     
         7 . The interlayer of  claim 6  wherein the thickness of each plasticized polyvinyl butyral layer is about 0.76 mm (30.4 mil).  
     
     
         8 . The interlayer of  claim 1  wherein the each layer of polyethylene terephthalate has a haze of less than about 1%.  
     
     
         9 . The interlayer of  claim 2  further comprising an additional functional layer.  
     
     
         10 . The interlayer of  claim 9  wherein the functional layer is a sound attenuating elastomer layer or a radiation blocking layer.  
     
     
         11 . The interlayer of  claim 1 , wherein the two or more sheets of bonded optical-grade polyethylene terephthalate are bonded with a pressure sensitive acrylic resin.  
     
     
         12 . The interlayer of  claim 1 , wherein the two or more sheets of bonded optical-grade polyethylene terephthalate are bonded with a layer of plasticized polyvinyl butyral.  
     
     
         13 . The interlayer of  claim 1 , wherein at least one layer of plasticized polyvinyl butyral has a Tg of at least 35° C.  
     
     
         14 . A composite laminate interlayer for a glass laminate consisting essentially of two sheets of bonded optical-grade polyethylene terephthalate between layers of plasticized polyvinyl butyral.  
     
     
         15 . The interlayer of  claim 14  wherein the thickness of each polyethylene terephthalate layer is between about 0.025 mm (1 mil) and about 0.175 mm (7 mil) and the thickness of each plasticized polyvinyl butyral layer is between about 0.125 mm (4 mil) and about 2 mm (80 mil).  
     
     
         16 . The interlayer of  claim 14 , wherein the two sheets of bonded optical-grade polyethylene terephthalate are bonded with a pressure sensitive acrylic resin.  
     
     
         17 . The interlayer of  claim 14 , wherein the two sheets of bonded optical-grade polyethylene terephthalate are bonded with a layer of plasticized polyvinyl butyral.  
     
     
         18 . The interlayer of  claim 14 , wherein at least one layer of plasticized polyvinyl butyral has a Tg of at least 35° C.  
     
     
         19 . A glass laminate comprising in order: 
 a) a first glass sheet,    b) a first layer of plasticized polyvinyl butyral,    c) a first layer of optical grade polyethylene terephthalate,    d) a second layer of optical grade polyethylene terephthalate,    e) a second layer of plasticized polyvinyl butyral, and    f) a second glass sheet.    
     
     
         20 . The glass laminate of  claim 19  wherein the thickness of the first and second glass sheets is between about 1 mm and about 10 mm, the thickness of each polyethylene terephthalate layer is between about 0.025 mm (1 mil) and about 0.175 mm (7 mil), and the thickness of each plasticized polyvinyl butyral layer is between about 0.1 mm (4 mil) and about 2 mm (80 mil).  
     
     
         21 . The glass laminate of  claim 20  wherein the thickness of the first and second glass sheets is between about 1 mm and about 10 mm, the thickness of each polyethylene terephthalate layer is about 0.175 mm (7 mil), and the thickness of each plasticized polyvinyl butyral layer is between about 0.375 mm (15 mil) and about 1.5 mm (60 mil).  
     
     
         22 . The glass laminate of  claim 19  wherein each layer of polyethylene terephthalate has a haze of less than 1%.  
     
     
         23 . The glass laminate of  claim 19  further comprising an additional functional layer.  
     
     
         24 . The glass laminate of  claim 23  wherein the functional layer is a sound attenuating elastomer layer or a radiation blocking layer.  
     
     
         25 . The glass laminate of  claim 19 , wherein the first layer of optical grade polyethylene terephthalate is bonded to the second layer of optical grade polyethylene terephthalate.  
     
     
         26 . The glass laminate of  claim 25 , wherein the first layer of optical grade polyethylene terephthalate is bonded to the second layer of optical grade polyethylene terephthalate with a pressure sensitive acrylic resin.  
     
     
         27 . The glass laminate of  claim 25 , wherein the first layer of optical grade polyethylene terephthalate is bonded to the second layer of optical grade polyethylene terephthalate with a layer of plasticized polyvinyl butyral.  
     
     
         28 . The glass laminate of  claim 19 , wherein at least one layer of plasticized polyvinyl butyral has a Tg of at least 35° C.  
     
     
         29 . A glass laminate consisting essentially of in order: 
 a) a first glass sheet,    b) a first layer of plasticized polyvinyl butyral,    c) a first layer of optical grade polyethylene terephthalate bonded to a second layer of optical grade polyethylene terephthalate,    d) a second layer of plasticized polyvinyl butyral, and    e) a second glass sheet,    wherein at least one layer of plasticized polyvinyl butyral has a Tg of at least 35° C.    
     
     
         30 . The glass laminate of  claim 29  wherein the thickness of the first and second glass sheets is between about 1 mm and about 20 mm, the thickness of each polyethylene terephthalate layer is between about 0.025 mm (1 mil) and about 0.175 mm (7 mil), and the thickness of each plasticized polyvinyl butyral layer is between about 0.1 mm (4 mil) and about 2 mm (80 mil).  
     
     
         31 . The glass laminate of  claim 30  wherein the thickness of the first and second glass sheets is between about 1 mm and about 10 mm, the thickness of each polyethylene terephthalate layer is about 0.175 mm (7 mil), and the thickness of each plasticized polyvinyl butyral layer is between about 0.375 mm (16 mil) and about 1.5 mm (60 mil).  
     
     
         32 . The glass laminate of  claim 29  wherein each layer of polyethylene terephthalate has a haze of less than 1%.  
     
     
         33 . The glass laminate of  claim 29 , wherein the first layer of optical grade polyethylene terephthalate is bonded to the second layer of optical grade polyethylene terephthalate with a pressure sensitive acrylic resin.  
     
     
         34 . The glass laminate of  claim 29 , wherein the first layer of optical grade polyethylene terephthalate is bonded to the second layer of optical grade polyethylene terephthalate with a layer of plasticized polyvinyl butyral.