| abstract |
A glass flake ( 10 ) having improved heat resistance and chemical resistance is formed from a glass base material satisfying, in mass %, 60≦SiO 2 ≦75, 5<Al 2 O 3 ≦15, 3≦CaO≦20, 6≦Na 2 O≦20 and 9≦(Li 2 O+Na 2 O+K 2 O)≦13. When 9≦(Li 2 O+Na 2 O+K 2 O)≦13 is satisfied in mass %, the CaO content and the Na 2 O content are preferably set within the ranges of 5≦CaO≦20 and 6≦Na 2 O≦13, respectively. When 13≦(Li 2 O+Na 2 P+K 2 O)≦20 is satisfied in mass %, the CaO content and the Na2O content are preferably set within the ranges of 3≦CaO≦15 and 9≦Na 2 O≦20, respectively. The working temperature of the glass base material is preferably 1180° C.-1300° C. The temperature difference ΔT obtained by taking the devitrification temperature of the glass base material from the working temperature of the glass base material is preferably 0° C.-200° C. The glass transition temperature of the glass base material is preferably 550° C.-700° C. The acid resistance index ΔW of the glass base material is preferably 0.05-1.5 mass %. |