JPS5813500B2 - Usuitagarasunoseizohouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing thin glass having a flat and smooth surface and a thickness of approximately several μ to 1.0 mm.

More specifically, a method for producing thin glass having excellent flatness and smoothness on both surfaces by utilizing the surface of a substrate having a flat and smooth surface and the surface tension itself of a solution capable of forming glass. We aim to provide the following.

Since the oil crisis in the fall of 1972, research and development into energy and resource conservation has been actively carried out around the world.

On the other hand, for architectural, vehicle, and other window glass, tempered glass, especially a plastic interlayer sandwiched in the center of two glass sheets, is used to avoid unexpected situations caused by glass breakage due to sudden accidents. The use of laminated glass is recommended, or legislation is being considered in some countries.

However, even though the use of laminated glass is promoted from the standpoint of respecting human life, the use of multiple sheets of glass itself goes against the idea of resource conservation, increases costs, and at the same time increases the weight of window glass for buildings and vehicles. In order to increase the strength of the structure itself, it becomes necessary to use an even larger amount of aggregate.

There is an urgent need to make the glass itself thinner.

Thinner glass plates are also required in the electronics field.

However, with the current technology, the thickness of plate glass that satisfies the required flatness and smoothness is approximately 1.5 yg or more, and the thickness that is fully satisfactory is 3 mm or more.

In particular, manufacturing thin glass with a thickness of 0.7 mm or less involves various difficulties, and specifically, thin glass with a thickness of 0.1 to 0.3 mm is used as a cover glass for optical microscopes, or for electronic parts and photographic plates. There is only thin glass with a thickness of 0.3 to 0.7 mm.

Moreover, it is difficult to say that these thin glass sheets have sufficiently excellent flatness and smoothness.

Regarding the manufacturing method, it is currently possible to manufacture up to a thickness of around 1.0 mm using the so-called Fourcor method or Colburn method, in which a molten glass substrate is pulled up and formed into a plate shape. When the thickness is around 0 mm, advanced technology and skilled work are required to form the glass plate, and the flatness and smoothness of the formed glass plate are unsatisfactory.Furthermore, when the thickness is less than 1.5 mm, the manufacturing yield is extremely low. Moreover, it is almost impossible to manufacture a glass plate with a thickness of 0.5 mm or less using the above molding method.

On the other hand, in order to make glass of 0.5 mm or less, there is a method called the roll-out method in which a hot glass substrate is drawn out through rolls, but this method results in a worse surface condition than the above-mentioned forming method.

Another method that has existed for a long time is to blow air into a high-temperature glass base to inflate it into a ball shape, then break it and stretch it to make a thin plate, but this method results in extremely poor surface flatness.

It must be said that it is extremely difficult to produce a flat, smooth thin sheet glass with a thickness of 1.5 mm or even 0.7 mm or less using current technology.

Based on this understanding of the current situation, the present inventors conducted research with the aim of developing a method for producing thin glass with excellent flatness and smoothness, and as a result, they succeeded in producing a method for producing thin glass according to the present invention.

That is, in the present invention, by applying a solution that can be dissolved into glass by heat treatment on the surface of a flat, smooth substrate, both sides can be made flat and smooth depending on the flatness and smoothness of the substrate surface and the surface tension of the solution. The method is characterized in that the solution coating film is vitrified by forming a coating film and firing the coating film, thereby producing thin glass.

Furthermore, the present invention provides, in this case, a fired thin sheet glass;
In order to make it easier to separate from the board, the surface of the board is coated with
Another feature is that a film is attached that can be removed by a subsequent melting process.

At the same time, the present invention also provides a first step of firing (hereinafter referred to as half-baking) until the coating film is not completely vitrified and becomes a soft film having a hardness that does not hinder handling. Next, a method for manufacturing thin sheet glass is provided, in which this semi-baked glass coating film is detached from the substrate, and then a second stage of firing (main baking) sufficient to vitrify the semi-baked glass coating film is performed. It also includes.

In particular, in the latter case, when the glass coating film is semi-baked, constituent organic substances, solvents, moisture, etc. are not sufficiently removed from the coating film, so it is soft and easily detached from the substrate. During final firing, since the firing is performed without a substrate or mold release film, no cracks occur due to the difference in thermal expansion coefficient between the substrate or mold release film and the thin glass, so no cracks occur in the thin glass.

Furthermore, the required dimensions of the thin glass sheet can be easily cut using scissors or a blade such as a razor in this half-baked state, and there is no need to carefully cut it with a glass cutter after final firing.

In addition, a mold release film is formed using a so-called stripbubble paint, and after half-baking, the semi-baked glass coating film and the mold release film (stripbable film) are simultaneously peeled off from the substrate, and the mold release film is left in this state. It is also possible to produce thin glass by performing final firing under firing conditions that are higher than the conditions at which the glass decomposes and disappears.

Stritz bubble paint, which is used to prevent surface scratches on glass and metal plates during transportation and storage, is generally commercially available, and all of them are organic solutions that easily decompose, carbonize, or disappear when heated above 200°C. Therefore, it is known that when high-temperature firing is performed as in the present invention, there is no adverse effect on the thin glass.

As mentioned above, the method of using a stripable film as a mold release film and peeling it off from the substrate while adhering this film to one side of the semi-baked glass coating film prevents the scattering of chips at the cut end during cutting. It has the advantage of preventing this and obtaining a good cut.

Various types of substrates can be used in the present invention, depending on the firing temperature of the solution that can be fired into a glass plate, but generally a plate glass, a metal plate, a plastic plate, a graphite plate, etc. are used.

Furthermore, as a solution that can be made into a glass plate by firing,
An organometallic solution or an alcoholate solution containing at least one metal having glass-forming ability such as silicon, titanium, vanadium, and phosphorus, or a mixture thereof is used.

Furthermore, water glasses such as silicates, borosilicates, phosphates, and borates can also be used.

Additives added to the organometallic solution or alcoholate solution containing one or more of the metals having glass-forming ability include sulfur, antimony, germanium, tin, silconium, and Organic or inorganic compounds such as beryllium, aluminum, and bismuth are used, and further organic or inorganic compounds such as magnesium, calcium, lithium, barium, sodium, ribidium, and cesium, whose oxides act as network modifiers of the glass, are used.

Other types of additives include chromium, cobalt, copper, iron, manganese, and
Inorganic or organic compounds such as nickel, gold, silver, etc. may also be used.

In the method of the present invention, the release film that facilitates separation of the substrate from the thin glass glass after firing is a film that is easily dissolved by acid, alkali, or aqua regia treatment when the solution forming the thin glass consists of an organic solvent. A metal thin film is effective, and when the solution used to form the thin glass is water glass-based and the "half-baking" process is performed, a release film other than the above-mentioned metal thin film may include a wax film, fatty acid, or A coating made of fatty acid ester or a plastic coating such as the above-mentioned stripbubble paint can be effectively used.

Next, one embodiment of the present invention will be specifically explained using the drawings.

In FIG. 1a, 1 is a flat and smooth substrate, in which polished plate glass is used.

Reference numeral 3 is a release coating, and a metal mesh was deposited to a thickness of about 20 OA by a normal vacuum deposition method.

As shown in FIG. 1b-2, a solution that becomes vitrified by firing was applied onto this using an applicator.

The solution used was 50 parts of semi-cured resin flakes (trade name: Glass Resin, manufactured by Owens-Illinois, USA) with an St02 content of approximately 30 parts, mainly consisting of organic silicone, and 20 parts of ethylene glycol heptanoethyl ether (commonly known as ethyl cellosolve). Laboratories and Raybow # as a flow control agent
This is a mixed solution of 2 parts of 3 (xylene solution).

In this state, the viscosity of the solution is about 80 boads, and Sto
2 content rate was about 21%.

Approximately 300 μm from the top of the release coating 3 on the substrate 1 is used as an applicator with a gap that forms a coating film thickness of 300 μm.
The solution was applied uniformly to a μ thickness.

After coating, it was left at room temperature for 1 hour to scatter most of the ethyl cellosolve solvent, and then placed in an electric furnace maintained at 250° C., the electric oven was turned off at the same time, and slowly cooled to approximately room temperature over 15 hours.

The solution applied by the above operation was fired to form a thin glass plate 2' on the substrate 1 with a release film 3 interposed therebetween.

(Figure 1C) shows this substrate 1, a release film, and a copper thin film 3.
The thin glass 2' is immersed in a vat containing a 2N aqueous solution of hydrochloric acid, and after about one hour, the copper thin film 3 is almost completely eluted and disappeared, and the thin glass 2' is separated from the surface of the substrate 1. did.

This is shown in Figure 1d, and the formed thin glass 2' is 7
The size is 0mm x 50wn and the thickness is 75μ (0.075mm), and when it was cut into approximately 30mm square pieces and the flatness (described later) was measured using an optical surface plate, it was approximately 200μ, which was excellent in flatness. It turned out that

At the same time, the surface of the thin glass 2' was observed using a reflected image of a fluorescent lamp, and it was found that it had excellent smoothness.

FIG. 2 shows an embodiment of the present invention which includes a "half-baking" process, in which 1 in a is a substrate, and 3 is a release film made of, for example, a stripbable film.

In FIG. 2b, a coating film 2 in the form of a solution, which will later become a glass plate, is applied onto a release film 3 formed on the surface of a substrate 1.

FIG. 2C shows the state after insufficient firing (half-baking), and 2' is the half-baked coating film.

Here, as shown in FIG. 2, the mold release film 3 and the semi-baked coating film 2' are peeled off from the substrate 1 and cut into a desired shape, followed by firing (final firing) sufficient to vitrify the film. A thin glass sheet 2h shown in FIG. 2e is obtained.

Alternatively, as shown in d' instead of d, the mold release film 3 may be dissolved away in the state C (half-baked), and only the half-baked coating film 2' may be separated.

When final baking the semi-baked coating film 2', it is preferable to carry out the final baking on a flat, smooth-surfaced support member made of a material (such as graphite) that does not wet glass.

Now, as a matter of basic caution when carrying out the present invention, it is most important to select a substrate with excellent flatness and smoothness, and at the same time, it is important to select a substrate with excellent flatness and smoothness. Careful attention should be paid to the coating method.

For example, vacuum evaporation, sputtering, vapor exposure, or dip coating are effective methods for attaching a release film that maintains the excellent surface condition of the substrate.On the other hand, as a solution coating method, ablator Recommended methods include coating method, dip coating method, and curtain coater method.

Furthermore, there are optimum conditions for the solid component concentration and viscosity of the vitrifying solution used, depending on the thickness of the required thin glass sheet.

The thickness of thin glass sheets suitable for the method of the present invention is from several microns to 700 microns, and the suitable viscosity of the vitrifying solution is from 0.3 to 1,000 poise, preferably from 1 to 600 poise.

If the viscosity is lower than this, the fluidity of the liquid will be large, and the thickness of the formed film will be too thin, and the smoothness will be easily lost when it is detached from the substrate in the form of a thin plate. The condition is poor and the surface smoothness is not excellent.

The firing temperature is 250°C or higher, preferably 550°C.
℃ or higher.

It has been found that at temperatures below 250°C, the organic components in the solvent or solution in the thin glass do not disappear sufficiently from the thin glass, so that a sufficient amount of inorganic glass cannot be obtained.

Furthermore, even when the firing is divided into two stages, a semi-baking process and a final firing process, the flatness and smoothness of the substrate on which the coating film of the vitrifying solution is formed are important factors.

This is because if the coating film formed in the half-baking process has unevenness, even if it is baked with great care on a support member with excellent flatness and smoothness in the final firing process, these unevenness will occur. This is because it does not disappear easily.

As described above, the present invention (1) attaches a release film that can be dissolved by subsequent melting treatment on a flat and smooth substrate surface, and forms glass on the surface of the release film by heat treatment. An aqueous solution of organic metal or inorganic glass in the form of a liquid solution is applied to a thin plate, and heated and fired to form a thin plate of glass.
It is an object of the present invention to provide a method for manufacturing thin glass, characterized in that the fired thin glass sheet is separated from the flat and smooth substrate surface by subjecting the meltable mold release film to a melting treatment. At the same time, (2) a release film that can be easily removed from the substrate surface by subsequent melting or peeling treatment is adhered to the flat and smooth substrate surface, and the release film is attached to the surface of the cut-off mold film. , an aqueous solution of organic metal or inorganic glass that can be formed into glass by heat treatment is applied to a thin plate, and the coating film is insufficiently fired (half-baked) so that it is not fully vitrified. After that, the coating film or the coating film and the release film are peeled off from the substrate surface, and then the coating film is removed with only the coating film or with the release film attached to the coating film. The present invention also provides a method for manufacturing thin glass, which is characterized by performing firing (firing) sufficient for vitrification.

The effects of the present invention will become clearer from the specific examples described below.

Table 1 shows the results of implementing the first method according to the present invention under three conditions.

Further, Table 2 shows the results of comparing the flatness and surface smoothness of the glass plate obtained in Table 1 with a commercially available glass plate (cover glass for microscope).

In Table 2, the flatness is determined by placing the glass plate on an optical surface plate.
Maximum lifting amount (warpage) of the plate from the pitch of the interference fringes that occur
The smoothness is the result of visually observing the distortion of the reflected image on the glass plate surface of the fluorescent lamp.

Example 2 Table 3 shows the conditions and results of the second method of the present invention, that is, when the applied solution was fired through a "half-baking" process.
Furthermore, Table 4 shows the results of quality comparison conducted in the same manner as in Example 1.

Example 3 On the surface of a polished plate glass measuring 150 mm x 85 mm x 3 mm, an acrylic stripbable paint (trade name: Trepank, manufactured by Fujikura Kasei Co., Ltd.) was applied to a thickness of about 14 μm using a dipping method and left at room temperature for 5 hours.

On top of this release film, 100 parts of semi-cured organic silicone resin flakes (trade name: Glass Range, manufactured by Owens-Illinois, USA), 20 parts of ethylene glycol monoethyl ether (commonly known as ethyl cellosolve), and Lembo as a flow control agent were added. 13 (a solution consisting of 2 parts of xylene solution was applied using a 500μ applicator).

After this was left at room temperature for 1 hour, it was heat-treated (half-baked) at 70° C. for 1 hour, and then the semi-baked coating film together with the release film was peeled off from the substrate glass.

Next, use scissors to remove the semi-baked coating film together with the release film.
It was cut into pieces of mm x 50 mm, placed on a graphite plate, fired for 15 minutes in an electric furnace at 500°C, and then slowly cooled.

The thickness of the obtained thin glass sheet was approximately 275 μm, and the surface exhibited good smoothness, and the flatness was approximately 75 μm at a thickness of 100 m×50 mm.

The thin glass thus obtained was transparent, and no carbon was observed on the release film.

As described above, the thin glass obtained by the present invention has superior flatness and smoothness compared to the thin glass obtained by conventional techniques, and it has been proven that it is sufficiently effective as a method for manufacturing thin glass. It was done.

[Brief explanation of drawings]

FIG. 1 shows the steps of a first method according to the present invention, and FIG. 2 shows the steps of the second method.

Claims (1)

[Claims] 1. A release film that can be dissolved by subsequent melting treatment is attached onto a flat and smooth substrate surface, and a solution capable of forming glass by heat treatment on the surface of the release film. An aqueous solution of an organic metal or an inorganic glass is coated in a thin plate shape, heated and fired to form a thin plate glass, and then the meltable mold release film is melted away to produce a fired thin glass plate. A method for producing thin glass, characterized by separating it from the flat and smooth substrate surface. 2. A release film that can be easily removed from the substrate surface by subsequent melting or peeling treatment is adhered onto a flat and smooth substrate surface, and glass can be formed on the surface of the release film by heat treatment. A coating film after applying an aqueous solution of organic metal or inorganic glass in the form of a thin plate and performing insufficient firing (half-baking) in which the coating film is not fully vitrified. The mold release film is peeled off from the substrate surface, and then the paint film alone or with the mold release film attached to the paint film is fired sufficiently to vitrify the paint film (final firing). A method for manufacturing thin glass, characterized by performing the following steps.