Alkali-free glass

Patent metadata

Field	Value
Publication number	US-11414339-B2
Application number	US-202017017891-A
Country	US
Kind code	B2
Filing date	Sep 11, 2020
Priority date	Mar 14, 2018
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

An alkali free glass has an average coefficient of thermal expansion at 50 to 350° C. of 30×10 −7 to 43×10 −7 /° C., a Young's modulus of 88 GPa or more, a strain point of 650 to 725° C., a temperature T 4 at which a viscosity reaches 10 4 dPa·s of 1,290° C. or lower, a glass surface devitrification temperature (T c ) of T 4 +20° C. or lower, and a temperature T 2 at which the viscosity reaches 10 2 dPa·s of 1,680° C. or lower. The alkali free glass contains, as represented by mol % based on oxides, 62 to 67% of SiO 2 , 12.5 to 16.5% of Al 2 O 3 , 0 to 3% of B 2 O 3 , 8 to 13% of MgO, 6 to 12% of CaO, 0.5 to 4% of SrO, and 0 to 0.5% of BaO. MgO+CaO+SrO+BaO is 18 to 22%, and MgO/CaO is 0.8 to 1.33.

First claim

The invention claimed is:

1. An alkali free glass having an average coefficient of thermal expansion at 50 to 350° C. of 30×10 −7 to 43×10 −7 /° C., a Young's modulus of 88 GPa or more, a strain point of 650 to 725° C., a temperature T 4 at which a viscosity reaches 10 4 dPa·s of 1,290° C. or lower, a glass surface devitrification temperature (T c ) of T 4 +20° C. or lower, and a temperature T 2 at which the viscosity reaches 10 2 dPa·s of 1,680° C. or lower, and
comprising, as represented by mol % based on oxides:
62 to 67% of SiO 2 ,
12.5 to 16.5% of Al 2 O 3 ,
0 to 3% of B 2 O 3 ,
8 to 13% of MgO,
6 to 12% of CaO,
0.5 to 4% of SrO, and
0 to 0.5% of BaO,
wherein MgO+CaO+SrO+BaO is 18 to 22%, and MgO/CaO is 0.8 to 1.33.

2. The alkali free according to claim 1 , having a glass specific elastic modulus of 34 MN·m/kg or higher.

3. The alkali free glass according to claim 1 , having a density of 2.60 g/cm 3 or lower.

4. The alkali free glass according to claim 1 , having a glass surface devitrification viscosity (η c ) of 10 3.8 dPa·s or higher.

5. The alkali free glass according to claim 1 , having, a glass transition temperature of 730 to 790° C.

6. The alkali free glass according to claim 1 , having a value expressed by the following Expression (I) of 4.10 or more:
(7.87[Al 2 O 3 ]−8.5[B 2 O 3 ]+11.35[MgO]+7.09[CaO]+5.52[SrO]−1.45[BaO])/[SiO 2 ]   Expression (I).

7. The alkali free glass according to claim 1 , having a value expressed by the following Expression (II) of 0.95 or more:
(−1.02[Al 2 O 3 ]+10.79[B 2 O 3 ]+2.84[MgO]+4.12[CaO]+5.19[SrO]+3.16[BaO])/[SiO 2 ]   Expression (II)

8. The alkali free glass according to claim 1 , having a value expressed by the following Expression (III) of 5.5 or less:
(8.9[Al 2 O 3 ]+4.26[B 2 O 3 ]+11.3[MgO]+4.54[CaO]+0.1[SrO]−9.98[BaO])×{1+([MgO]/[CaO]−1) 2 }/[SiO 2 ]  Expression (III).

9. The alkali free glass according to claim 1 , comprising 0.5% or lower of SnO 2 as represented by mol % based on oxides.

10. The alkali free glass according to claim 1 , having a β-OH value of 0.05 to 0.5 mm −1 .

11. The alkali free glass according to claim 1 , having a compaction of 100 ppm or lower.

12. The alkali free glass according to claim 1 , having an equivalent cooling rate of 5 to 500° C./min.

13. The alkali free glass according to claim 1 , which is a glass sheet having at least one side of 1,800 mm or longer and a thickness of 0.7 mm or less.

14. The alkali free glass according to claim 13 , which is manufactured by a float process or a fusion process.

15. A display panel comprising the alkali free glass according to claim 1 .

16. A semiconductor device comprising the alkali free glass according to claim 1 .

17. An information recording medium comprising the alkali free glass according to claim 1 .

18. A planar antenna comprising the alkali free glass according to claim 1 .

Assignees

• Agc Inc

Inventors

• Tokunaga Hirofumi
• Ono Kazutaka

Classifications

• C03C3/091 Primary

  containing aluminium · CPC title

• C03C3/087 Primary

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• G11B7/2531

  comprising glass · CPC title

• C03C2203/10

  Melting processes · CPC title

• G02F1/1333

  Constructional arrangements; {Manufacturing methods}(G02F1/135, G02F1/136 take precedence) · CPC title