Alkali-free glass

Abstract

To provide glass that exhibits minimal self-weight deflection, excellent thermal shock resistance, superior moldability, and low burden on glass manufacturing equipment. [Solution] Density is 2.6 g / cm³ 3 Below, the Young's modulus is between 90 GPa and 100 GPa, and the average coefficient of thermal expansion at 50-350°C is 30 × 10⁻⁶. -7 / K or more 39×10 -7 / K or less, glass viscosity 10 4 The temperature T4 at which dPa·s occurs is 1350℃ or less, and the glass surface devitrification temperature (T c Alkali-free glass having a temperature of T4 + 80℃ or less, a specific modulus of elasticity of 36 MN·m / kg or more, and a specified glass composition.

Claims

1. Density is 2.6 g / cm³ ３ Below, the Young's modulus is between 90 GPa and 100 GPa, and the average coefficient of thermal expansion at 50-350°C is 30 × 10⁻⁶. －７ / K or more 39×10 －７ / K or less, glass viscosity 10 ４ Temperature T at which dPa·s occurs ４ The temperature is below 1350°C, and the glass surface devitrification temperature (T ｃ ) is T ４ Below +80°C, with a specific modulus of 36 MN·m / kg or more. In mole percent based on oxides SiO ２ 55% to 80% Al ２ O ３ 12% to 20% B ２ O ３ 5% or less, MgO 5% or more and 18% or less, CaO 0.1% or more and 12% or less, SrO 0.1% or more and 8% or less, BaO 0% or more and 6% or less It contains, MgO / CaO is 1 or more, If MgO / (MgO+CaO+SrO+BaO) is 0.5 or higher, MgO + Al ２ O ３ between 24% and 38%, Equation (I) is (-3.125 × [SiO ２ ]-2.394×[Al ２ O ３ ] -3.511 × [B ２ O ３ ]-2.167×[MgO]-2.608×[CaO]-3.161×[SrO]-3.583×[BaO]+3.795×10 ２ Alkali-free glass, where the value of equation (I) is between 90 and 100 when given the condition.

2. Equation (II) is (0.213 × [SiO ２ ]+1.006×[Al ２ O ３ ] -0.493 × [B ２ O ３ ]+1.158×[MgO]+1.386×[CaO]+3.092×[SrO]+4.198×[BaO]+2.004×10 ２ The alkali-free glass according to claim 1, wherein when this is the case, the value of formula (I) / formula (II) × 100 is 36 or more.

3. The alkali-free glass according to claim 1, wherein the content of MgO + CaO + SrO + BaO is 20% or less.

4. The alkali-free glass according to claim 1, wherein the ratio of (MgO + CaO) / (SrO + BaO) is 8 or greater.

5. The alkali-free glass according to claim 1, wherein the strain point is 700°C or higher and 740°C or lower.

6. Glass viscosity 10 ２ Temperature T at which dPa·s occurs ２ The alkali-free glass according to claim 1, wherein the temperature is 1590°C or higher and 1690°C or lower.

7. When the average coefficient of linear expansion at 50 to 350°C is α, Young's modulus is E, and the photoelastic constant is C, their product α・E・C is 9.2 × 10⁻⁶. －７ The alkali-free glass according to claim 1, wherein the temperature is less than or equal to / K.

8. The alkali-free glass according to claim 1, wherein the photoelastic constant is 31 nm / MPa / cm or less.

9. The alkali-free glass according to claim 1, wherein the glass transition temperature is 730°C or higher and 850°C or lower.

10. The devitrification viscosity of the glass surface is 10 ３．４ The alkali-free glass according to claim 1, wherein the pH is dPa·s or higher.

11. In mole percent based on oxides, ZrO ２ The alkali-free glass according to claim 1, containing 0 to 1% of [the specified substance].

12. Li ２ O, Na ２ O and K ２ The alkali-free glass according to claim 1, wherein the total amount of O is 0.2% or less in mole percent based on oxides.

13. SnO ２ The alkali-free glass according to claim 1, containing 0% or more and 0.5% or less of [the substance].

14. The alkali-free glass according to claim 1, containing 0% or more and 1% or less of F in mole percentage.

15. The β-OH value of the glass is 0.05 mm －１ 0.6 mm or more －１ The alkali-free glass according to claim 1, which is as follows:

16. A glass plate containing alkali-free glass as described in any one of claims 1 to 15, wherein at least one side is 2400 mm or longer and the thickness is 1 mm or less.

17. A method for producing alkali-free glass according to any one of claims 1 to 15, wherein the glass is formed by a float method or a fusion method.

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