US 12,421,158 B2
Glass fiber and composition for glass fibers
Aya Nakamura, Mie (JP)
Assigned to NIPPON SHEET GLASS COMPANY, LIMITED, Tokyo (JP)
Appl. No. 18/249,482
Filed by Nippon Sheet Glass Company, Limited, Tokyo (JP)
PCT Filed Dec. 28, 2022, PCT No. PCT/JP2022/048527
§ 371(c)(1), (2) Date Apr. 18, 2023,
PCT Pub. No. WO2024/105894, PCT Pub. Date May 23, 2024.
Claims priority of application No. 2022-183744 (JP), filed on Nov. 16, 2022.
Prior Publication US 2024/0158282 A1, May 16, 2024
Int. Cl. C03C 3/087 (2006.01); C03C 3/089 (2006.01); C03C 13/00 (2006.01)
CPC C03C 3/087 (2013.01) [C03C 3/089 (2013.01); C03C 13/00 (2013.01); C03C 2213/00 (2013.01)] 12 Claims
 
1. A glass composition for glass fibers, comprising, in mass %:
 
 
 SiO2 59.5 to 62.5%;
 
 Al2O3 19 to 21.2%;
 
 B2O3  0 to 0.5%;
 
 MgO 16 to 18%;
 
 CaO  0 to 1.5%;
 
 Li2O  0 to 1.0%;
 
 Na2O  0 to 0.2%;
 
 K2O  0 to 0.1%;
 
 TiO2  0 to 5%;
 
 ZrO2  0 to 5%;
 
 ZnO  0 to 1.5%; and
 
 F2  0 to 0.1%
 
wherein a sum (SiO2+Al2O3+MgO) of a SiO2 content, a Al2O3 content, and a MgO content is 95% or more in mass %,
the glass composition has a Young's modulus of 97 GPa or more,
the glass composition is substantially free of rare-earth oxides,
the glass composition has a density of 2.45 g/cm3 or more and 2.6 g/cm3 or less,
ΔT determined by subtracting a devitrification temperature TL from a temperature T3 at which a viscosity becomes 103 dPa·s is a positive value; and
ΔW1 is 0.1 mass % or less, when the glass composition is formed into a glass monofilament having a diameter of 15 μm and a length of 20 mm, where ΔW1 is a mass decrease rate determined for a case where the glass composition has a mass in grams equivalent to a specific gravity of the glass composition and is immersed for 60 minutes in 80 mL of sulfuric acid having a specific gravity of 1.2 and a temperature of 99° C.