JPS60166242A - Tempering of glass - Google Patents

Abstract

PURPOSE:To carry out the tempering treatment of a thin glass plate without causing the breakage of the glass during cooling, by heating a glass plate at a high temperature, and dipping and quenching in a viscous oil heated at a low temperature. CONSTITUTION:A thin glass plate is heated at a high temperature (about 600- 700 deg.C) near the critical temperature to cause the deformation of the glass, and is quenched rapidly by dipping in an incombustible viscous oil (e.g. engine oil) heated at a relatively low temperature higher than normal temperature (i.e. about 65 deg.C). The method is suitable especially to a thin glass plate having a thickness of about 1mm.. The abrupt temperature decrease in cooling can be mitigated, and the breakage of the glass plate by the strain can be prevented by this process. Even a thin glass plate tempered by this process forms granular pieces when broken under impact.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for strengthening sheet glass, particularly a method suitable for strengthening thin sheet glass.

When sheet glass is damaged due to impact, etc., the damage does not occur in a straight line;
Tempered glass that breaks into granules is widely used in automobiles and other applications because it prevents injuries caused by broken glass pieces. Normally, sheet glass is strengthened by heating it to a high temperature and then rapidly cooling it by spraying water or air on it. However, this method is limited to relatively thick glass plates, and thin glass plates of about 1 to 2 layers will be damaged during rapid cooling. For this reason, the current situation is that thin sheet glass is strengthened by chemical or mechanical methods.

As a result of research, this invention has developed a method that reliably produces glass that breaks into granules even when thin sheet glass is used, by using viscous oil heated to a low temperature during cooling.Examples of the method are described below in n#j. After heating a thin sheet glass of about 1 to 2 degrees Celsius to a limit temperature of 600 to 700 degrees Celsius without deforming it, it is rapidly cooled by immersing it in nonflammable viscous oil, such as engine oil, heated to about 65 degrees Celsius, which is slightly higher than room temperature. do.

By processing in this way, thin sheet glass that would be damaged by water cooling or air blowing can be processed without being damaged, and can be easily damaged over a wide area without being damaged by local impact or distortion.
It begins to break into particles that are about the same thickness.

This damage situation has already been put into practical use with conventional 3mm or thicker glass, but with this invention, 1m
The feature is that it can be applied to thin sheet glass of around 300 m.

In other words, in the case of conventional cooling methods using water cooling or air blowing, the thin glass could not withstand the strain stress caused by thermal contraction during rapid cooling and broke. It absorbs the temperature of the glass surface and forms a high-temperature oil film, and the viscosity of this high-temperature oil film cushions the sudden instantaneous temperature drop on the glass surface. This is thought to be due to the synergistic effect of heating to a certain degree and relaxing the instantaneous cooling during immersion.

Note that the heating temperature of the essential oil is changed as appropriate depending on the properties of the essential oil, the thickness of the glass, and the properties.

Furthermore, although the above embodiments have been described with respect to thin plate glass, even in the case of thick glass, the breakage rate during processing can be reduced by the same method as in the above case.

Patent applicant: Hiroyuki Yukawa Agent: Patent attorney Kazu1) Akira

Claims (1)

[Claims] After heating the plate glass to a high temperature close to the limit temperature that will not deform it,
A method for strengthening glass, characterized by immersing it in viscous oil heated to a low temperature above room temperature and rapidly cooling it.