Lead- and barium-free crystal glass

US7202188B2 · kind B2 · utility

Assignee

• D. Swarovski & Co. · AT

Inventors

• Gerold Sprachmann · Kolsassberg, AT
• Johannes Maier · Tuntenhausen, DE

Key dates

• Filing date: Sep 18, 2006
• Grant date: Apr 10, 2007
• Expiry date: Sep 18, 2026

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C3/097
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A lead- and barium-free crystal glass having a refractive index of at least 1.55, with in % by weight, more than 50% and less than 60% SiO2, more than 0.6% and less than 4% B2O3, less than 3% K2O, more than 12% and less than 15% Na2O, more than 4% and less than 11% CaO, more than 0.25% and less than 5% Al2O3, less than 2% MgO, and between 8 and 16% ZnO, with the proviso that the total content of the oxides of Pb, Ba and As is below 0.1%, the total content of the oxides of Ti and La is below 5% and the total content of the oxides of Nb, Ta, Yb, Y, W, Bi and Zr is below 5%, wherein at most 1% oxides of Nb, Ta and Yb respectively and 3% of the oxides of Y, W, Bi and Zr respectively are included.