Patent ID: 7498283

Claim:
A glass powder having an average particle size of at least 0.5 μm and smaller than 5.0 μm, and having a specific surface area of at least 1.5 m 2 /cm 3 , which glass powder substantially has the following composition as represented by mol % based on oxides, and has a glass transition temperature higher than 300° C. and lower than 400° C.: P 2 O 5 : 22 to 27%, SO 3 : 3 to 18%, ZnO: 10 to 55%, Al 2 O 3 : 1 to 5%, B 2 O 3 : 5 to 15%, Li 2 O+Na 2 O+K 2 O: 5 to 35% (provided that Li 2 O: 0 to 15%, Na 2 O: 3 to 15%, K 2 O: 0 to 10%), MgO: 0 to 15%, CaO: 0 to 15%, BaO: 0 to 15% and SnO: 0 to 15%.