Unlock instant, AI-driven research and patent intelligence for your innovation.

Alkali-free glass and method for producing same

A technology of alkali-free glass and manufacturing method, which is applied in the direction of instruments, optics, identification devices, etc., and can solve problems such as increased devitrification temperature

Active Publication Date: 2015-04-15
ASAHI GLASS CO LTD
View PDF13 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0018] Patent Document 7 discloses a 2 o 3 The glass is divided into "containing 55 ~ 67% by weight SiO 2 And contains 6 ~ 14% by weight Al 2 o 3 Glass" (group a) and "containing 49 to 58% by weight SiO 2 And contains 16 ~ 23% by weight Al 2 o 3 glass" (group b), however, group a due to SiO 2 The content is large, so there exists as SiO 2 The raw material silica sand cannot be completely melted in the molten liquid and remains in the form of unmelted silica sand; group b is due to Al 2 o 3 There is a lot of content, so there is a problem that the devitrification temperature rises significantly

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Alkali-free glass and method for producing same
  • Alkali-free glass and method for producing same
  • Alkali-free glass and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0120] Hereinafter, Examples 1 to 5 and 11 to 16 are Examples, and Examples 6 to 7 are Comparative Examples. The raw materials of each component are blended into the target composition, and are melted at a temperature of 1500 to 1600°C using a platinum crucible. When melting, stir with a platinum stirrer to homogenize the glass. Then, the molten glass is poured, formed into a plate shape, and then slowly cooled.

[0121] Table 1 shows the glass composition (unit: mol%) and the thermal expansion coefficient at 50 to 300°C (unit: ×10 -7 / °C), strain point (unit:°C), glass transition temperature (unit:°C), specific gravity, Young's modulus (GPa) (measured by ultrasonic method), as a high-temperature viscosity value, which serves as a standard for melting Temperature T 2 (logη=2, that is, the viscosity reaches 10 2 Temperature at parking, unit: °C) and temperature T, which is the benchmark for float formability and melt formability 4 (logη=4, that is, the viscosity reaches 10 4 Pois...

example 6

[0131] In Example 6, SiO 2 More than 70 mol%, MgO is less than 6 mol%, MgO / (MgO+CaO+SrO+BaO) is less than 0.35, MgO / (MgO+CaO) is less than 0.52, so the temperature T is the benchmark for melting 2 Higher than 1710°C, poor melting. In addition, the temperature T which is the basis of float formability and melting method 4 It is higher than 1330℃, so float forming and melt forming are difficult.

example 7

[0132] In Example 7, MgO / (MgO+CaO+SrO+BaO) is lower than 0.35, and MgO / (MgO+CaO) is lower than 0.52, so the strain point is lower, lower than 725°C.

[0133] For the glass of the composition of Example 5, change the SiO as shown below 2 The silicon source and alkaline earth metal source are used to evaluate the meltability of glass.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
strain pointaaaaaaaaaa
strain pointaaaaaaaaaa
strain pointaaaaaaaaaa
Login to View More

Abstract

The present invention provides an alkali-free glass that has a high strain point, low viscosity and low devitrification, and is easily subjected to float molding and fusion molding. The present invention relates to an alkali-free glass having a strain point of 725°C or higher; an average thermal expansion coefficient at 50 to 300°C of 30 × 10 -7 to 40 × 10 -7 / °C; a temperature T 2 at which a glass viscosity becomes 10 2 dPa·s of 1,710°C or lower; a temperature T 4 at which a glass viscosity becomes 10 4 dPa·s of 1,330°C or lower; a glass surface devitrification temperature (T c ) of 1,330°C or lower; a glass internal devitrification temperature (T d ) of 1,330°C or lower, and including, in terms of mol% on the basis of oxides, SiO 2 : 66 to 70, Al 2 O 3 : 12 to 15, B 2 O 3 : 0 to 1.5, MgO: 6 to 9.5, CaO: 4.5 to 8, SrO: 2 to 7, BaO: 0 to less than 1, and ZrO 2 : 0 to 2, provided that MgO + CaO + SrO + BaO is 14 to 18.2, MgO / (MgO + CaO + SrO + BaO) is 0.35 or greater, MgO / (MgO + CaO) is 0.52 or greater, and MgO / (MgO + SrO) is 0.45 or greater, in which the alkali-free glass does not substantially contain alkali metal oxides.

Description

Technical field [0001] The present invention relates to an alkali-free glass suitable as a substrate glass for various displays or a substrate glass for a photomask, does not substantially contain an alkali metal oxide, and is capable of float forming and melt forming (down-draw forming). Background technique [0002] Conventionally, various substrate glasses for displays, particularly substrate glasses on which a metal or oxide thin film is formed on the surface, have required the following characteristics. [0003] (1) If an alkali metal oxide is contained, alkali metal ions will diffuse into the thin film and deteriorate the film characteristics. Therefore, it is required that the alkali metal ions are not substantially contained. [0004] (2) When exposed to high temperatures in the film formation process, in order to minimize the deformation of the glass and the shrinkage (thermal shrinkage) associated with the stabilization of the glass structure, a high strain point is require...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C03C3/091C03B1/00C03C3/087C03C3/093C03C6/00G02F1/1333G09F9/30
CPCG02F2001/133302C03C3/087C03C3/093C03C1/00C03C3/091G02F1/133302C03B18/02
Inventor 永井研辅黑木有一西泽学辻村知之
Owner ASAHI GLASS CO LTD