Patent ID: 8763429
Filing Date: 2014-07-01
Classification: C03B,C03C

Abstract:
1. A method for producing alkali-metal free glass sheets by a downdraw process comprising selecting, melting, and fining batch materials so that the glass making up the sheets comprises SiO 2 , Al 2 O 3 , B 2 O 3 , MgO, CaO and BaO, and, on an oxide basis, comprises: (i) a MgO content greater than or equal to 2.0 mole percent; (ii) a CaO content greater than or equal to 3.0 mole percent; (iii) a BaO content greater than or equal to 1.0 mole percent; and (iv) a SiO wherein: (a) the glass satisfies, and said mole percent contents are limited by, the relationships: (b) the fining is performed without the use of substantial amounts of arsenic; and (c) a population of 50 sequential glass sheets produced by the downdraw process from the melted and fined batch materials has an average gaseous inclusion level of less than 0.10 gaseous inclusions/cubic centimeter, where each sheet in the population has a volume of at least 500 cubic centimeters.