LEAD-FREE GLASS, AND GLASSWARE AND DECORATIVE PRODUCTS THEREFROM Russian patent published in 1999 - IPC

FIELD: manufacture of lead-free glass and glassware and decorative crystal glass products therefrom. SUBSTANCE: lead-free glass has density of at least 2.9 g/cubic cm and refraction coefficient of at least 1.545. Glass comprises (wt %): SiO₂, 53-62; SrO, not higher than 3; ZrO₂ not higher than 4; Na₂O, 2-7; ΣSiO₂+Al₂O₃+ZrO₂, 55-65; K₂O, 3-11; ΣNa₂O+K₂O, 8-14; CaO, not higher than 5; BaO 15-19; ZnO, 8-13; ΣSrO+BaO+ZnO, 17-32; Li₂O, not higher than 2; ΣLi₂O+Na₂O+K₂O not higher than 14; Al₂O₃, not higher than 3; and ΣSrO+BaO+ZnO not higher than 32. Glass comprises at least one transition metal or rare-earth metal oxide in amount not exceeding 0.1%. EFFECT: lead-free glass having density of at least 2.9 g/cubic cm and refraction coefficient of at least 1.545. 10 cl, 15 ex, 2 tbl