Process for preparing a copper containing sealing glass

Claim 1

A process for forming a copper oxide containing sealing glass composition comprising the steps of: forming a first portion of said glass, including the relatively high melting point oxides, said portion consisting essentially of, by weight based on the total weight of said composition; PbO 32.15 to 32.9%, Al 2 O 3 1 to 2%, ZnO 10.5 to 12.5%, SiO 2 2 to 3%, Bi 2 O 3 0 to .75%, B 2 O 3 6.5 to 7.5%, in the absence of CuO by heating said first portion until homogeneous melt is formed at a melt temperature of about 1,100° C for at least about 1 hour and no more than about 11/4 hour; forming a second portion of said glass, including the relatively low melting point oxides, said portion consisting essentially of, by weight based on the total weight of said composition; PbO 32.15 to 32.9 percent, Bi 2 O 3 0 to 0.75%, B 2 O 3 6.5 to 7.5%, and CuO 3.5 to 5% by heating said second portion, except said CuO, until a homogeneous melt is formed at a melt temperature of about 1050° C for at least about 3/4 hour and not more than about 1 hour, reducing the temperature of said melt to from about 750° to about 800° C, adding the CuO to the melt and maintaining the melt at temperatures from about 750° to about 800° C until the melt is homogeneous; combining said first and second portions at a temperature of from about 750° to about 800°C and maintaining the resulting combined melt of said first and second portions at a temperature of from about 750° to about 800° C until said melt is homogeneous, and cooling said melt to produce a glass composition in which the conversion of CuO to Cu 2 O is below about 10% by weight.