Method for the Production of Fire Resistant Glazing

Abstract

Fire resistant glazings having improved properties comprising a silicate based interlayer which contains from 35% to 43% by weight of water may be produced using a cast in place process. The amount of water in the interlayer is reduced by concentrating the silicate solution or by introducing silica in the form of a silica sol. Preferably a mixture of an aqueous sol and an organosol is used. Polyhydroxy compounds and saccharides may be incorporated into the interlayer to improve the properties thereof and to reduce the water content. The silicate based formulations are pourable and can be used in a cast in place production process and subsequently cured to form an optically clear interlayer.

1 . A method for the production of a fire resistant laminated glazing comprising a silicate based interlayer which interlayer is formed by pouring a mixture comprising an alkali metal silicate solution and a silica sol into a cavity between two opposed glass panes and allowing the mixture to cure without drying wherein the water content of the mixture is between 35% and 43% by weight. 
     
     
         2 . The method according to  claim 1 , wherein the water content of the mixture is between 38% and 42% by weight. 
     
     
         3 . The method according to  claim 1 , wherein the silica sol comprises a mixture of an aqueous silica sol and an organic silica sol. 
     
     
         4 . The method according to  claim 1 , wherein the sols comprise at least 30% by weight of solid material. 
     
     
         5 . The method according to  claim 4 , wherein the sols comprise at least 50% by weight of solid material. 
     
     
         6 . The method according to  claim 1 , wherein the silica sol comprises particles having an average particle size in the range 7 to 50 nm. 
     
     
         7 . The method according to  claim 1 , wherein the alkali metal silicate solution comprises from 40% to 62% by weight of water. 
     
     
         8 . The method according to  claim 7 , wherein the alkali metal silicate is a potassium silicate. 
     
     
         9 . The method according to  claim 8 , wherein the potassium silicate comprises a molar ratio SiO 2  to K 2 O of at least 1.4:1. 
     
     
         10 . The method according to  claim 1 , wherein the molar ratio of SiO 2  to M 2 O, where M represents an alkali metal cation in the mixture, is at least 4:1. 
     
     
         11 . The method according to  claim 10 , wherein the molar ratio of SiO 2  to M 2 O is at least 4.5:1.