Durable functional glass enamel coating for automotive applications
The present invention provides glass compositions and glass coatings that are lead-free and cadmium-free for use on glass substrates, particularly in automotive applications. The compositions of the present invention provide for chemically durable, blacker colors that are completely suitable for use in automotive glass windows. The compositions include tantalum oxide as a required component.
1. A lead-free, cadmium-free glass frit acceptable for use in automotive applications, consisting essentially of in percent by weight from about 8% to about 45% SiO 2 , up to about 7% ZnO, up to about 4% B 2 O 3 , from about 40% to about 80% Bi 2 O 3 , up to about 4% Na 2 O, up to about 8% K 2 O, up to about 4% Li 2 O, from about 0.1% to about 22% Ta 2 O 5 , up to about 1% Nb 2 O 5 , up to 4% of each of Al 2 O 3 , TiO 2 , ZrO 2 and BaO, up to about 1% of each of SrO, Sb 2 O 3 , Mo 2 O 3 MgO, P 2 O 5 and CaO, up to about 3% F 2 , and up to about 4% of one or more of La 2 O 3 , Nd 2 O z , Pr 2 O 3 and Ce 2 O 3 .
2. The lead-free, cadmium-free composition according to claim 1 which includes in percent by weight from about 11% to about 35% SiO 2 , from about 0.25% to about 5% ZnO, up to about 2% B 2 O 3 , up to about 2% Na 2 O, from about 0.25% to about 2% BaO, up to about 2% of each of TiO 2 and ZrO 2 , from about 0.1% to about 5% K 2 O, from about 45% to about 75% Bi 2 O 3 , up to about 1% Nb 2 O 5 , from about 0.25% to about 2% Li 2 O, from about 0.1% to about 16% of Ta 2 O 5 , from about 0.1% to about 2% F 2 , and from about 0.1% to about 3% of one or more of La 2 O 3 , Nd 2 O z , Pr 2 O 3 or Ce 2 O 3 .
3. The lead-free, cadmium-free composition according to claim 2 which includes in percent by weight from about 16% to about 25% SiO 2 , from about 1% to about 4% ZnO, from about 0.25% to about 3% K 2 O, from about 54% to about 71% Bi 2 O 3 , from about 0% to about 1% Nb 2 O 5 , from about 0.5% to about 1% Li 2 O, from about 0.25% to about 11% of Ta 2 O 5 , from about 0.1% to about 1% F 2 , from about 0.25% to about 1% Al 2 O 3 , from about 0.5% to about 1% BaO, and from about 0.25% to about 2% of one or more of La 2 O 3 , Nd 2 O z , Pr 2 O 3 or Ce 2 O 3 .
4. The glass frit according to claim 1 which includes from about 0.25% to about 11% Ta 2 O 5 .
5. The glass frit according to claim 1 which includes from about 54% to about 71% Bi 2 O 3 .
6. The glass frit according to claim 3 which is substantially free of Nb 2 O 5 .
7. The glass frit according to claim 1 which is substantially free of Nb 2 O 5 .
8. A glass enamel composition comprising the glass frit composition according to claim 1 .
9. A glass enamel composition comprising the glass frit composition according to claim 3 .
10. A glass enamel composition comprising the glass frit composition according to claim 4 .
11. A glass enamel composition comprising the glass frit composition according to claim 5 .
12. A glass enamel composition comprising the glass frit composition according to claim 6 .
13. A glass enamel composition comprising the glass frit composition according to claim 3 together with a medium selected from water miscible media, thermoplastic media, spray media, roller coater media, pad transfer media, UV curable media, and mixtures thereof.
14. A glass enamel composition comprising the glass frit composition according to claim 1 together with a medium selected from water miscible media, thermoplastic media, spray media, roller coater media, pad transfer media, UV curable media, and mixtures thereof.