JPS6197147A - High strength glass - Google Patents

Abstract

PURPOSE:To obtain a high strength glass having a deep and strong stress layer by inserting a glass body to be treated into a specified inorg. compd. to obtain capsules comprising said glass and treating the capsules at high temp. and under high pressure applied statically and isotropically. CONSTITUTION:A glass body to be treated comprising such as soda glass or borosilicate glass, etc. is inserted into at least one kind of inorg. compd. (e.g. KNO3) of elements selected from Li, Na, K, Rb, and Cs to form capsules. Then, the capsule is charged to a high pressure vessel and treated at high temp. and under high pressure applied statically and isotropically in a liquid or inert gas atmosphere within a temp. range from below a transition point of the glass body to >=100 deg.C, and under >=several hundreds kg/cm pressure. By this method, the strength of the conventional glass body (e.g. cover glass for watch) is increased to >=two times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to high-strength glass that has been strengthened by ion exchange at high temperature and high pressure.

[Conventional technology]

Conventionally, high-strength glass has been produced using physical strengthening methods in which the glass is heated to around its softening temperature and then rapidly cooled with air or liquid to create compressive stress on the glass surface, as well as nitric acid at a temperature below the glass transition point (for example, 400°C). Power IJ (KN
Na, O@ OIL O, S in the molten salt of O3)
i Immerse glass in OH7% (7) to form Ma+ ions and K
Ti ion! Exchange 1. There are a chemical strengthening method in which internal stress is generated on the glass surface using K ions with a large ionic radius, a surface crystallization method, and a combination of these methods. Although each of these can increase the strength by 6 to 20 times that of unstrengthened glass, this is still insufficient depending on the application. Particularly in fields where thinning is strongly desired, such as cover glass for watches, the current strength of glass has reached its limit, and the uses of glass are expanding further, and glass is being used as an alternative to metals, ceramics, etc. Nowadays, stronger glass is required.

[Problem that the invention seeks to solve]

However, as mentioned above, no matter which tempering treatment method or glass is used, conventional high-strength glass cannot be used in any of the following aspects, such as the depth of the strengthening treatment, the strength of the internal stress generated, and the possible range of ion exchange. Due to this limitation, it was not possible to obtain the high-strength glass that is needed today.

The present invention solves these problems by forcibly performing ion exchange on the glass surface using both temperature and pressure. This is something that was successfully formed over time.

[Means for solving problems]

In the high-strength glass of the present invention, the glass body to be treated is Li, H
Inserted into an inorganic compound consisting of one or more of a, K, R'b, and Os, and encapsulating the whole,
The capsule is then subjected to static isotropic high temperature and high pressure treatment.

[Effect]

Next, let's talk about the members that make up the present invention. First, regarding glass, we will talk about soda glass, shelf silicate glass,
The type of glass is not particularly limited, such as silica glass, but soda-based glass is effective both in terms of strength and cost. Regarding inorganic compounds consisting of one or more of Li, Na, K, Rb, and Os, there are nitrates, sulfates, carbonates, phosphates, chlorides, heptadides, etc. of each element. As long as it is an inorganic compound, the type is not particularly important, but potassium nitrate is effective in terms of temperature, workability, economical efficiency, etc. Next, regarding encapsulation, although it differs depending on the type of inorganic compound used, melting point, etc., iron rust such as stainless steel and soft iron, or ion-exchangeable material in the composition, and internal glass material to be treated. Glasses with lower softening points are suitable.

Next, when talking about static isotropic high-temperature, high-pressure processing, first of all, liquid or gas is used as the pressure medium in order to apply pressure without directionality, and nitrogen is used as the pressure medium.

An inert gas such as argon is effective. In order to make the effects of the present invention more noticeable and to promote them, it is necessary to take advantage of the synergistic effect in combination with temperature. The temperature varies depending on the type of glass used, the type of inorganic compound, the encapsulation material, etc., but a temperature of 100°C or higher, below the transition point of the glass body to be treated, is effective.If the temperature is lower than this, sufficient ion exchange will not occur. If it does not occur, or if it is too high, the stress will be relaxed. The pressure is several hundred
A value of t/- or more, preferably 10001&/d or more is effective.

〔Example〕

Sin, 72, N'&, 015, Mut, 0,2°C
a06, Mg04, Na1SO,Q, 5 (wt%)
A watch cover glass made of
It is inserted into a stainless steel frame with a large overall shape of ~10 tla, and then potassium nitrate powder is filled into the gap between the watch cover glass and the stainless steel frame, and the stainless steel frame is sealed to encapsulate it.

After that, the capsule was inserted into a high-pressure container, and the temperature was increased while argon gas was flowing, until the pressure reached 120,011.
P/d, when the temperature reaches 550℃, hold for S time. After heating, cool to room temperature, and when it reaches room temperature and pressure, take it out from the high-pressure container, and then melt I from the capsule and make a watch cover. Take out the glass.

When the characteristics of the watch cover glass subjected to the strengthening treatment in this manner were compared with those of the watch cover glass subjected to the conventional strengthening treatment, as shown in Table 1, each characteristic value was significantly improved.

Table 1 [Effects of the Invention] As described in the examples above, the watch cover glass according to the present invention has a strength that is more than twice as strong as that of a watch cover glass that has been subjected to conventional chemical strengthening treatment. In addition, it has become possible to perform the strengthening process in about 115 hours to ensure the same depth of 6 layers as before. In addition, it has been confirmed that watch cover glass, which could previously only be made as thin as 1 meter, can be made ultra-thin and still have the same strength as the α5. This was an extremely effective development in terms of design.

In addition, in the examples, only cover glass for watches was described, but the product of the present invention can also be used in glass substrates for display panels, contributing to thinning, and can also be used in various parts for which glass has been conventionally used. This makes it possible to provide high-strength glass that can be widely applied as a substitute for metals and ceramics and is extremely effective industrially.

that's all

Claims (1)

[Claims] The glass body to be treated is inserted into an inorganic compound consisting of one or more of Li, Na, K, Rb, and Cs to encapsulate the entire body, and then the capsule is exposed to static isotropic high temperature. , high-strength glass characterized by high-pressure treatment.