Patent ID: 6797658
Filing Date: 2004-09-28
Classification: C03C

Abstract:
A glass composition, comprising:SiO2â€‚â€‰70 to 75 weight percentNa2Oâ€‚â€‰12 to 15 weight percentK2Oâ€ƒâ€‰0 to 5 weight percentCaOâ€‚>9 weight percentMgOâ€‚<4 weight percentAl2O30.01 to 4 weight percentSO3â€ƒâ€‰0 to 1 weight percentFe2O3â€ƒâ€‰0 to 2 weight percentwherein:SiO2 + Al2O3&gE;70 weight percentNa2O + K2O12-17CaO + MgOâ€‚9-less than 13.4CaO + R2O +23-29Al2O3wherein the glass composition provides a melting temperature in the range of about 2510Â° F. to about 2650Â° F. (1376Â° C. to 1454Â° C.), a forming temperature in the range of about 1800Â° F. to 1894Â° F. (982Â° C. to 1034Â° C.), and a liquidus temperature in the range of about 1780Â° F. to 1850Â° F. (971Â° C. to 1010Â° C.).