Patent ID: 9115021
Filing Date: 2015-08-25
Classification: C03C

Abstract:
1. A neutral grey glass composition, with a sodium-calcium-silicate base consisting essentially of: SiO 2 from 68 to 75% wt; Al 2 O 3 from 0 to 5% wt.; CaO from 5 to 15% wt; MgO from 0 to 10% wt; Na 2 O from 10 to 18% wt; K 2 O from 0 to 5% wt.; SO 3 from 0.05 to 0.30% wt., and the following primary colorants: Fe 2 O 3 from 0.40 to 0.80% wt., TiO 2 from 0.05 to 2.0% wt; Er 2 O 3 from 0.2 to 2.5% wt.; Se from 0 to <10 ppm; CuO from 20 to 200 ppm; 0.0 to 0.1% wt. carbon; and 15 to 50% ferrous (redox), in which the glass has an illuminant “A” light transmission of greater than 65%, solar transmission (T s )<55%, ultraviolet transmission <40%, with color values of a*=−4 to 3, and b*=4 to −2.