JPS62275044A - Method for chemically reinforcing polished glass - Google Patents

Abstract

PURPOSE:To enable transparent chemical reinforcement without cloudiness and warpage by immersing and treating polished glass in a melting salt incorporating specified ions large in ionic radius and thereafter immersing and pretreating it in the melted salt incorporating Na ion or Li ion and then chemically reinforcing it. CONSTITUTION:Polished glass especially surface-polished glass produced by a floating system is immersed and treated in a melted liquid incorporating K ion or Rb ion at 350-510 deg.C for 1-600sec. Then after immersing and pretreating it in the melted salt incorporating Na ion or K ion, it is chemically reinforced by a low temp. type ion exchange method. A chemically reinforced glass product, little in amount of warpage, of high strength and also transparent can be produced by immersing it into the melted salt incorporating K ion or Rb ion having ionic radius larger than Na ion or Li ion for the above-mentioned slight time before immersing and pretreating it in the melted salt incorporating Na ion or Li ion.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to polished glass, particularly glass manufactured by the float method and polished, such as Soda-lime float glass, which has been polished to a level close to that of a fire-making surface with a grade 3 or less, is used as a substrate for ``Kinkiko'' materials, especially glass substrates for original disks, glass substrates for photomasks, various displays, device parts, etc. This invention relates to chemically strengthened glass that can be applied to chemically strengthened glass with low warpage, good flatness, and high strength, and a chemical strengthening method that can be applied to float glass.

In addition to the above, the present invention also provides thin, large-area architectural and vehicle window glasses, molded products using float glass, cooking glass products, and substrates for various electronic and electrical devices, etc.
It is widely used.

[Conventional technology]

Float glass has six-sided smoothness, flatness, and uniformity in thickness compared to various types of plate glass, so it is used not only in fields such as architecture and vehicles, but also in the field of electronic materials, such as displays such as liquid crystals and plasma. It is becoming widely used.

Furthermore, as a recent trend, thin glass sheets with a thickness of 3 rran or less are being used, and as the thickness becomes thinner, the strength is desired to be improved.

In order to make an effective analogy with thin sheet glass, it is common practice to apply chemical strengthening methods such as low-temperature or high-temperature alkali ion substitution. Warping occurs (e.g., 0.4-1.5 trm150 diameter).

The cause of the warpage is due to the influence of molten metal, usually an, penetrating into the contact glass during float molding of the glass, but no innovative solution to this warpage has been found. For example, the Sn-infiltrated surface of glass is ground and polished and then subjected to alkali ion replacement treatment, but the Sn diffusion layer on the Sn-contact glass surface is 10 to 20 μm, and the maximum thickness In this method, not only is the process complicated, but the grinding and polishing itself is problematic in that it causes cracks and defects in the rounded glass, and it is also expensive.

Therefore, in the above-mentioned method, float glass was not used for the original disk substrate or the like.

Therefore, the non-applicant has already applied for Taiha-Koku 60-4492
6 etc., there is a difference in the composition of glass components in a part of the surface between the surface in contact with the bath molten metal (hereinafter referred to as the bottom surface) and the non-contact @ (hereinafter referred to as the top surface) during molding in float glass production. Since this occurs, correct the difference,
In order to increase the amount of ion exchange during strengthening, Ic, Na
A method has been proposed in which chemical strengthening is performed after immersion treatment in a molten salt containing ions or a mixed molten salt that also contains Ll ions. This has made it possible to provide a high-strength chemically strengthened float glass that is inexpensive, has a narrow surface state, and has less warpage.

In order to conveniently use the float glass as a substrate,
It is necessary to cut the glass into a predetermined shape and finish the entire end surface.At this time, a protective film is often coated using PVC-based melting pages and alcohol-based solvents to prevent scratches on the glass surface. being done.

However, even if the above-mentioned scratch prevention measures are taken, scratches may still occur on the glass surface.
It was necessary to polish the surface to about 2.0 μm using an abrasive such as 0eO1.

The CeO2 polishing differs greatly in the amount of glass coating layer removed from the commonly used secondary surface grinding, and the Sn diffusion layer in the float glass remains without being removed.

Therefore, on the polished float glass, the % Gu Zhao 6
If the measures such as 0-44926 are applied as they are, there is a problem that a clouding phenomenon occurs on the glass surface although the mountain range is not uneven.As a result, while preventing the clouding phenomenon, the warping is small and the breaking strength is further increased. Therefore, it is difficult to recycle the polished float glass into products such as substrates.

In addition, although glass manufactured by methods other than the float method does not have a Sn diffusion layer, its narrow surface conditions such as surface smoothness are poorer than that of float glass, and it is chemically strengthened by surface grinding and polishing. .

However, in an attempt to further increase the breaking strength of a glass substrate manufactured by a method other than the float method or a glass substrate which has been ground and polished down to the sn diffusion layer of float glass, the breaking strength of the glass substrate manufactured by a method other than the above-mentioned float method has been proposed.
If these methods are applied as they are, there is still a problem that cloudiness occurs on the glass surface.

[Problem that the invention seeks to solve]

As mentioned above, when polished glass, especially float glass, has a concave shape as it is, pre-treatment by immersion in molten salt containing Na ions or Ll ions as a measure to prevent warping during chemical strengthening and improve fracture strength. This results in clouding of the glass surface, making it impossible to obtain chemically strengthened glass products that are transparent, have high strength, and have little warpage.

[Means to solve the problem]

The present invention has been made in view of the conventional drawbacks, and the present invention has been made in view of the above-mentioned drawbacks of the prior art. To provide a method for chemically strengthening polished glass, in which even polished glass, especially float glass, can be made into a high-strength, transparent chemically strengthened glass product with less warping by immersing it in a glass solution for an extremely short period of time. be.

In other words, the invention is that when polished glass, especially float glass, is pretreated by immersion in a molten salt containing 8 layers or Li ions, and then chemically strengthened by a low-temperature ion exchange method, the front plate is Provided is a method for chemically strengthening polished glass, which comprises immersing the glass in a bath molten salt containing Ni or R1) ions at 350 to 510°C for 1 to 600 seconds, and then sequentially performing the immersion pretreatment and chemical strengthening. It is something.

Here, in the case of non-invention, the person who chose the X ion is Ll
Ions or Na ions are not effective in eliminating the cloudiness, and X ions, which have a larger ionic radius than these ions, are effective, and even if Rb ions are used, the objective can be achieved in the same way.

According to the present invention, there is a feature that the time for immersion in the molten salt containing K or R1) ions can be extremely short. In other words, 1 in a molten salt of 510°C or lower and 350°C or higher.
~600 seconds is an extremely short and unique processing time from the concept of chemical strengthening.In other words, in the case of chemical strengthening, ion exchange is most promoted within the limited temperature range. Even at the upper limit of 510℃
Processing time of 2 hours or more is required, and more than 10 hours at 350°C.
b The significance lies in changing the hexagonal state of the glass, rather than chemically strengthening it with molten salt containing ions, and it is far from being chemically strengthened for τμ.
Even with an extremely short treatment time, it is sufficiently effective in preventing clouding.

Therefore, the treatment temperature for preventing clouding in P] 1 was set at 350 to 51.
The reason for setting 0c is that when the temperature exceeds 510°C, it becomes difficult to correct the amount of warpage, the next l properties of the glass deteriorate, and the chemical stability of m molten salt containing [6 or Rb ions] This is because the molten salt becomes very poor, and the control of the molten salt becomes clumsy, and the efficiency of preventing clouding becomes poor.At 350° C., the activity of the molten salt is not due to light and does not work effectively.

The preferred processing temperature is 400 to 490 doors.

Furthermore, the reason why the processing time for preventing white clouding is set to 1 to 600 seconds is that if it is less than 1 second, it will not work sufficiently to prevent clouding, although it depends on the size of the glass to be treated. This is the ninth time that Ji's correction becomes pregnant.

[Effect] K+1 As mentioned above, the surface of the glass will not become cloudy even at the special meeting of the Institute by applying the uninvented immersion treatment, pre-immersion treatment, chemical strengthening treatment, and treatment with Shunkue Sung sweat. This makes it possible to obtain chemically strengthened glass products that are transparent and free of oxidation.

That is, according to the present invention, the glass manufactured by the float method and polished remains in a state close to that of a pyrotechnic surface even after polishing, and can solve the problems of cloudiness and anti-9. Fracture toughness can also be significantly increased by about 30% compared to conventional glass that has been simply chemically strengthened. Even in the case of polished glass, the problem of cloudiness can be solved, and the fracture strength is significantly increased by about 30%, similar to that of polished 70-4 glass.

As a result, it is possible to cope with the surface scratches that occur during float glass cutting at a relatively low cost and to regenerate the glass. This means that it can be commercialized as a transparent substrate with high breaking strength.

〔Example〕

Examples of the present invention will be described below.

Comparative Examples 1 to 4 Approximately 1 ffl with approximately 1 μm seed-like scratches on the surface
Co
1. Using the material from which the 1,000 oz. has been removed by polishing with 1.1, perform the specified first treatment with potassium nitrate A under the conditions shown in the FBI in P1, and then apply the specified 5 g in sodium copper plating.
After the treatment in step 2, the sample was chemically strengthened with potassium nitrate.

Five samples each were visually inspected for surface condition, breaking strength was measured using concentric load bending method, and the amount of warpage was determined using D1nKTAKAE (5
The measurement was carried out using a shape measuring instrument (manufactured by LOAN). The results are shown in the Example of Cloth 1, and the destructive strength test was the average value of the five sheets, and the amount of warpage showed variation among the five sheets.

Comparison? IJ I~6 Using the same polished glass substrate as in implementation ν1j, Table 1
The results were shown in Comparative Example 1, which was measured using the same method as in the examples.

Table 1 However, for the amount of reciprocity, a positive value indicates a convexity on the top surface, and a negative value indicates a convexity on the bottom surface.

〔Effect of the invention〕

I 1 shows a comparison of the above-mentioned embodiments of the present invention and comparative examples.
As is clear from the above, even when scratches occur on the surface, they can be sufficiently recycled to, for example, disk substrates, and the original quality of high-quality float glass with high strength and little warping can be achieved with thin float glass substrates. It is something that takes advantage of its characteristics.

Furthermore, the present invention also applies to glass polished by 8u.
Since the number of destructive strong earthquakes can be increased and transparency can be maintained, it can be used in a wider range of fields than before.

Claims (1)

[Claims] After pre-treating polished glass, especially float glass, by immersing it in a molten salt that also contains Na ions or Li ions, when chemically strengthening it by low-temperature ion exchange method, etc.
A method for chemically strengthening polished glass, which comprises immersing the glass in a molten salt containing Rb ions at 350 to 510° C. for 1 to 600 seconds, and then sequentially performing the immersion pretreatment and chemical strengthening.