Glass flake and coated glass flake
AssigneeNippon Sheet Glass Co., Ltd.
InventorsKosuke Fujiwara, Akihiro Koyama
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Abstract
Disclosed is a glass flake (10) having improved heat resistance and improved chemical durability, which is composed of a glass base material satisfying, as expressed in mass %, 60≦SiO2≦70, 5≦Al2O3≦15, 1≦MgO≦10, 10≦CaO≦25 and 4<(Li2O+Na2O+K2O)<9. The temperature difference ΔT obtained by taking the devitrification temperature of the glass base material from the working temperature thereof is preferably within the range of 0-200° C. The glass transition temperature of the glass base material is preferably within the range of 560-750° C. It is desirable that the value of ΔW, which serves as an index for the acid resistance of the glass base material, is within the range of 0.05-1.2 mass %.
Claims9
A glass flake being characterized in that the glass flake is formed from a glass base material comprising, expressed in percent by mass:
- 63≦SiO2≦70;
- 10.85≦Al2O3≦15;
- 1≦MgO≦10;
- 10≦CaO≦17.77;
- 4.08≦(Li2O+Na2O+K2O)<9;
- and
- 0≦Fe2O3≦5,
- wherein the content of Li2O is 1.30 percent by mass or greater and ZnO is substantially not contained,
- wherein a temperature difference ΔT obtained by subtracting a devitrification temperature from a working temperature of the glass base material, which is the temperature when the viscosity of molten glass is 100 Pa·sec (1000 P), is 0° C. to 200° C.,
- wherein a glass transition temperature of the glass base material is 560° C. to 750° C., and
- wherein ΔW, which is a mass decrease rate measured by immersing the glass base material in a sulfuric acid aqueous solution for 72 hours at 80° C. and representing an index for acid resistance of the glass base material, is 0.05 to 1.2 percent by mass.
Dependencies are inferred from the claim text.