# US 8,785,336 B2 · Alkali-free glass

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- Number: US 8,785,336 B2
- Document ID: US8785336B2
- Status: Granted
- Kind: B2
- Application number: 13/415,889
- Filed: 2012-03-09
- Published: 2012-11-08
- Granted: 2014-07-22
- Earliest claimed: 2011-03-14
- Assignees: Nippon Electric Glass Co., Ltd.
- Applicants: Takahiro Kawaguchi; Shinkichi Miwa
- Inventors: Takahiro Kawaguchi; Shinkichi Miwa
- Web page: https://patentgrep.com/patent/US8785336B2

## CPC

- C03C 3/091: containing aluminium
- C03C 3/093: containing zinc or zirconium
- C03C 3/095: containing rare earths
- C03C 3/097: containing phosphorus, niobium or tantalum
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

Provided is an alkali-free glass, comprising, as a glass composition in terms of mass %, 55 to 80% of SiO2, 10 to 25% of A12O3, 2 to 5.5% of B2O3, 3 to 8% of MgO, 3 to 10% of CaO, 0.5 to 5% of SrO, and 0.5 to 7% of BaO, having a molar ratio MgO/CaO of 0.5 to 1.5, being substantially free of alkali metal oxides, and having a Young's modulus of more than 80 GPa.

## Claims

### Claim 1

An alkali-free glass, comprising, as a glass composition in terms of mass %, 55 to 80% of SiO2, 10 to 25% of Al2O3, 2to 5.5% of B2O3, 4 to 8% of MgO, 3 to 7.5% of CaO, 0 to 5% of SrO, 0.5 to 7% of BaO, and 0 to 2% of ZnO, having a molar ratio MgO/CaO of 0.5 to 1.3, being substantially free of alkali metal oxides, having a Young's modulus of more than 80 GPa, having a liquidus temperature of 1,195° C. or less, and having an average thermal expansion coefficient in a temperature range of 30 to 380° C. of 30 to 44.2×10−7/° C.

### Claim 2 (depends on 1)

The alkali-free glass according to claim 1, further comprising 0.001 to 1 mass % of SnO2.

### Claim 3 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has a strain point of more than 680° C.

### Claim 4 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has a liquidus temperature of less than 1,195° C.

### Claim 5 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has an average thermal expansion coefficient in a temperature range of 30 to 380° C. of 30 to 39.2×10−7/° C.

### Claim 6 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has a temperature at 102.5 poise of less than 1,600° C.

### Claim 7 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has a viscosity at a liquidus temperature of 104.8 poise or more.

### Claim 8 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass is formed by an overflow down-draw method.

### Claim 9 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass has a thickness of less than 0.5 mm.

### Claim 10 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass is used for an OLED device.

### Claim 11 (depends on 1)

The alkali-free glass according to claim 1, wherein the alkali-free glass comprises in terms of mass %, 4.5 to 8% of MgO.