Low-melting, lead-free ceramic frits

Claim 2

A lead-free, low melting and durable glass frit composition adapted to have an incipient fusion point below about 475° C. and a solubility in water of less than 0.6 percent; measured by exposure to water at 100° C. for one hour, the glass frit consisting essentially of on a weight basis: 13 to 24 parts alkali oxide selected from 0 to 22 parts Na 2 O, 0 to 6 parts Li 2 O, and 0 to 22 parts K 2 O; 14 to 27 parts B 2 O 3 ; 2 to 8 parts Al 2 O 3 ; 35 to 55 parts SiO 2 ; 0.75 to 4 parts F; at least 5 parts other oxide selected from 0 to 6 parts TiO 2 , 0 to 11 parts ZnO, and 0 to 5 parts P 2 O 5 , provided that at least two of said oxides are included in measurable amounts; and provided that the sum of all parts, exclusive of F, totals 100 weight parts.

Claim 3

The lead-free glass frit composition in claim 1, comprising: 13 to 22 parts Na 2 O; 0 to 3 parts Li 2 O; 0 to 1 part K 2 O; 18 to 22 parts B 2 O 3 ; 3 to 8 parts Al 2 O 3 ; 40 to 46 parts SiO 2 ; 1 to 3 parts F; 0 to 4 parts TiO 2 ; 7 to 11 parts ZnO; and 2 to 3 parts P 2 O 5 .

Claim 4

The lead-free glass frit composition in claim 1 containing 0 to 2 parts MgO.

Claim 5

The lead-free glass frit composition in claim 1 containing 0 to 2 parts CaO.

Claim 6

The lead-free glass frit composition in claim 1 containing 0 to 4 parts zirconia.

Claim 7

The lead-free glass frit composition in claim 1 containing 0 to 1 part MoO 3 .

Claim 8

In a process for producing a durable glass frit composition by melting oxide producing batch materials at temperatures above about 1000° C. to produce glass frit, the improvement comprising: proportioning the batch materials to provide a glass frit having an oxide analysis based on 100 total weight parts consisting essentially of, 13 to 24 parts alkali oxides selected from 0 to 22 parts Na 2 O plus 0 to 6 parts Li 2 O plus and 0 to 22 parts K 2 O, 14to 27 parts B 2 O 3 , 2 to 8 parts Al 2 O 3 , 35 to 55 parts SiO 2 , at least 5 parts other oxide selected from 0 to 6 parts TiO 2 plus 0 to 11 parts ZnO plus 0 to 5 parts P 2 O 5 provided that at least two of said other oxides are included in measurable amounts; and including in said batch materials, fluorides containing between about 2 and 13 parts fluorine wherein a portion of said fluorine volatilizes to provide between 0.75 and 4 parts fluorine (F) in said glass frit, whereby said glass frit composition is lead free and has an incipient fusion point less than about 475° C. and a solubility in water of less than 0.6 percent; measured by exposure to water at 100° C. for one hour.

Claim 9

In a process for producing a durable glass frit composition by melting oxide producing batch materials at temperatures above about 1000° C. to produce glass frit, the improvement comprising: proportioning the batch materials to provide a glass frit having an oxide analysis based on 100 total weight parts consisting essentially of, 13 to 24 parts alkali oxides selected from 0 to 22 parts Na 2 O plus 0 to 6 parts Li 2 O plus and 0 to 22 parts K 2 O, 14to 27 parts B 2 O 3 , 2 to 8 parts Al 2 O 3 , 35 to 55 parts SiO 2 , at least 5 parts other oxide selected from 0 to 6 parts TiO 2 plus 0 to 11 parts ZnO plus 0 to 5 parts P 2 O 5 provided that at least two of said other oxides are included in measurable amounts; and including in said batch materials, fluorides containing between about 2 and 13 parts fluorine wherein a portion of said fluorine volatilizes to provide between 0.75 and 4 parts fluorine (F) in said glass frit, whereby said glass frit composition is lead free and has an incipient fusion point less than about 475° C. and a solubility in water of less than 0.6 percent; measured by exposure to water at 100° C. for one hour.