JP3075906B2 - Substrate coated with water-soluble salt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate coated with a water-soluble salt.

[0002]

2. Description of the Related Art Conventionally, for the purpose of avoiding and removing contamination adhering to a surface during the manufacture, storage and transportation of a substrate, (1) the atmosphere around the substrate is cleaned, (2) interleaf paper and spacers Prevent transfer of contaminants from materials in contact with or in the vicinity of the substrate, such as a storage container, and (3) remove contaminants adhered before necessary operations by washing having physical and chemical actions. The method was being implemented.

[0003]

With the recent development of material science, high cleanliness is often required on the surface of a material, and the presence of a very small amount of contamination becomes a problem. For example, "water repellency", which is repelled in fields requiring a clean glass surface, is manifested by a very small amount of organic substances adsorbed on the surface.

Therefore, it has been extremely difficult to completely avoid the adsorption of trace amounts of organic substances by cleaning the atmosphere around the glass substrate and selecting a material in contact with or near the glass substrate surface.

When the glass substrate is handled in large and large quantities, such as architectural and vehicular plate glass, television cathode ray tube glass, etc., it is difficult to adjust the atmosphere and select related materials at a high cost. The use of insufficient materials such as spacers, corrugated cardboard, etc. has had to be used, and avoiding surface contamination has been more difficult.

[0006] Further, once adhered organic substances are formed on the glass surface by forming hydrogen bonds with silanol groups on the surface, and are often not removed by simple water washing, but are often washed by chemical and physical actions. Was required, which was a pressure factor in cost. A similar situation is a common problem when handling not only a glass substrate but also a substrate requiring a clean surface.

The present invention takes into account that it is difficult to completely avoid contamination of the substrate and that the substrate is often washed after storage, transport and before each required operation, Provided is a substrate capable of easily removing adhesion contamination more easily than before.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a substrate having a water-soluble salt coated on its surface and having a water-soluble salt film that dissolves and desorbs in water, wherein the water-soluble salt is a carbonate. , bicarbonate, nitrate, phosphate, silicate, at least one member selected from the borates and the group consisting of double salts, that provides a substrate water-soluble salts is applied.

The water-soluble salt in the present invention is at least one water-soluble salt selected from the group consisting of carbonates, bicarbonates, nitrates, phosphates, silicates, borates and double salts thereof. Sex salts are used. In particular, water-soluble salts such as carbonates such as lithium, sodium and potassium, nitrates, phosphates, silicates and borates are preferably used . In the present invention, a colloidal substance dispersed as fine particles in water, such as zeolite, bentonite, and hydrous aluminum silicate, can also be used.

[0010] The substrate in the present invention is preferably a substrate selected from the group consisting of glass, plastics, ceramics, single crystal, and those whose surfaces are coated with an inorganic or organic substance .

When the substrate is glass, the water-soluble salt is preferably an alkaline salt, because the glass surface is slightly dissolved. Examples of the alkaline salt include one or more selected from the group consisting of sodium tripolyphosphate, sodium sesquicarbonate, sodium hydrogen carbonate, sodium carbonate, sodium tetraborate, and potassium tetraborate.

When transparency is required, for example, for inspection of a substrate, it is desirable to use a substance such as potassium tetraborate that does not become cloudy due to a change in efflorescence or the like.

The method of applying the water-soluble salt may be, for example, a method of impregnating a spray, dip, or roll-shaped cloth or sponge as an aqueous solution and applying it to the surface. The aqueous solution concentration of the water-soluble salt is preferably about 0.01 mol / l from the viewpoint of ease of removal at the time of washing, cost, and waste liquid treatment, but the optimum value varies depending on the type of the substrate, the application, and the state of contamination.

If it is necessary to shorten the drying time due to process restrictions, the drying time is reduced to 1/10 by adding 1 to 10% by volume of an organic solvent such as ethyl alcohol and forcibly air-drying. It can be shortened to the following.

When cleaning the substrate, as a cleaning agent,
Using a cleaning agent composed of water and / or a surfactant, immersion in a cleaning water tank and spraying of the cleaning water have a sufficient effect. Furthermore, the effect can be expected to be improved by using an ultrasonic device or a brush in combination.

[0016]

In the present invention, the contaminants flying on the surface of the substrate coated with the water-soluble salt adhere to the water-soluble salt film and do not directly contact the surface of the substrate. When the substrate in this state is washed with water, contaminants are easily removed from the substrate by being accompanied by the water-soluble salt film which dissolves and desorbs in water, and a clean substrate surface is obtained.

Further, since the water-soluble salt film itself has electric conductivity, dust is hardly attached due to an antistatic effect. In particular, it adheres to the surface of a television panel, burns in by a heat treatment in a later step, and is effective in reducing dust, which is a defect, called paper powder.

[0018]

EXAMPLES Example 1 Table 1 shows an example for soda-lime glass. Soda lime glass is a 1.1 mm thick float glass. When the glass top surface (the tin non-contact surface in the tin bath) is subjected to various treatments such as polishing, washing, drying, application of a water-soluble salt, and contamination operation with ceria, contact of the glass top surface is performed. The corners were measured and the cleanliness was evaluated.

The operation for adhering contamination, "contamination operation", is performed by hollowing a glass test piece in a desiccator filled with dioctyl phthalate (DOP), which is a typical plasticizer and tends to cause water repellency of glass. Hanging 48
Sealed for hours.

In this case, the water-soluble salt is applied at a rate of 0.01 mol / each of sodium tripolyphosphate, sodium sesquicarbonate, sodium tetraborate and potassium tetraborate.
The glass was immersed in an aqueous solution and dried. The water washing was performed for 30 seconds under flowing pure water at room temperature.

As shown in Table 1, the glass B that had been subjected to the direct contamination operation did not show a decrease in the contact angle even after washing with water (glass C).
Glass D coated with sodium tripolyphosphate, sodium sesquicarbonate, sodium tetraborate, potassium tetraborate, glass F,
It can be seen that the contact angles of the glass H and the glass J after the water washing were reduced to the level (glass A) before the contamination operation, the DOP contamination was easily removed by the water washing, and the clean surface was recovered.

According to this example, it can be understood that the contamination caused by the organic molecules flying and adsorbing on the glass stored in a clean room or the like can be removed by a very simple washing with water.

Example 2 Table 2 shows an example in which the invention was applied to glass for a TV funnel.
Cut the glass for TV funnel into 1cm square, 1%
ESC shows the removal status of contamination on the glass surface when various treatments such as immersion in HF-1% H ₂ SO ₄ aqueous solution for 3 minutes, washing with water, drying, application of a water-soluble salt, and contamination operation were performed.
It was measured by the peak intensity ratio of A (photoelectron spectroscopy) (C _1s / Si _2p ). However, the C _1s peak measured a peak of 284.6 eV, and the Si _2p peak measured a peak of 103.4 eV.

The water-soluble salt was applied by dipping the glass in a 0.01 mol / l aqueous solution of sodium tripolyphosphate, sodium hydrogen carbonate, sodium tetraborate, and potassium tetraborate, and drying. Pollution operation and water washing were performed in Example 1.
Is the same as

As shown in Table 2, the ESCA peak intensity ratio indicating the attachment of DOP after the "contamination operation" was increased in any of the glasses, but the value was almost decreased in the glass N not coated with the water-soluble salt. In contrast, in glass P, glass R, glass T, and glass V coated with sodium tripolyphosphate, sodium hydrogen carbonate, sodium tetraborate, and potassium tetraborate, the values decreased to the initial values, and D
It can be seen that OP was removed by washing with water.

This example shows that the inner surface of the funnel becomes water-repellent during storage and is not recovered even by washing with water, which can solve the problem in the process of causing repelling failure of the carbon slurry (dug).

Example 3 An example in which the present invention is applied to quartz glass as a medium of a photoacoustic element and lithium niobate (LiNbO ₃ ) as a piezoelectric crystal will be described. The quartz glass and LiNbO ₃ received during the process were cleaned in a cleaning line in the process. The washed sample was immersed and dried in a 0.01 mol / l aqueous solution of sodium tripolyphosphate, and was stored in a clean room for 4 days and washed with water in both cases of immersion and non-immersion. Table 3 shows the results of measuring the contact angle of the surface of the sample after each treatment.

Table 3 shows that the contamination attached to the surface of the photoacoustic element medium and the surface of the piezoelectric crystal during storage can be removed by simple washing with water by applying sodium tripolyphosphate.

Example 4 An example in which the invention is applied to a solar cell cover glass for an artificial satellite will be described.
After the cover glass is washed with isopropyl alcohol, it is immersed in a 0.01 mol / l aqueous solution of sodium tripolyphosphate, a 0.01 mol / l aqueous solution of sodium sesquicarbonate or a 0.01 mol / l aqueous solution of sodium tetraborate, dried, and then dried. Table 4 shows the results of measuring the contact angles after storage for 10 days and washing with water. In addition, Table 4 shows the contact angles before and after water washing when not immersed in each aqueous solution as blanks.

Table 4 shows that contamination transferred from the expanded polystyrene container during storage can be easily removed by washing with water by applying sodium tripolyphosphate, sodium sesquicarbonate or sodium tetraborate on the surface. .

Example 5 An example in which the invention is applied to an ultra-thin glass sheet for liquid crystal (1.1 mm thick) will be described. After washing the ultra-thin glass, 0.01 mol / l of each of sodium tripolyphosphate and sodium tetraborate
After being immersed in an aqueous solution or a 0.1 mol / l aqueous solution and air-dried, an interleaf paper for glass was inserted between the glasses. This was stored in a thermo-hygrostat at 20 ° C. and 80% RH for 10 days, and then washed with water. Table 5 shows the results of measuring the contact angle (°) before and after washing. Table 5 also shows a case where the same operation was performed without immersion in an aqueous solution of sodium tripolyphosphate (blank).

From Table 5, the contamination (paper at) transferred from the glass insert to the glass surface during storage was washed with water regardless of the type and properties of the insert (oil, fat, water absorption, surface smoothness, etc.). It can be seen that it is easily removed.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

By washing the substrate of the present invention with water,
Contaminants on the substrate surface are easily removed from the substrate by being accompanied by a water-soluble salt film which dissolves and desorbs in water, and a clean substrate surface is obtained. Therefore, an effect is obtained that the cleanliness of the atmosphere in which the substrate is manufactured, stored, and transported does not need to be highly enhanced for the purpose of reducing contaminants adhering to the substrate surface. In addition, there is also an effect that dust and the like hardly adhere due to an antistatic effect.

When manufacturing, storing, and transporting the substrate,
In order to reduce the transfer of contaminants from materials such as interleaf paper and spacers that come into contact with the substrate surface and materials such as corrugated cardboard and styrofoam that exist in the vicinity, the selection tolerance of these materials, which was conventionally restricted, is large. The effect of enlargement is obtained.

Further, there is obtained an effect that the washing step performed before use is simplified. That is, even if a surfactant used as a detergent, an ultrasonic cleaner provided in a cleaning tank, a brush, and the like are omitted, the same or better contamination removing effect can be expected.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-116512 (JP, A) JP-A-6-51523 (JP, A) JP-A-56-25970 (JP, A) JP-A-59-1979 96280 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09K 3/00 112 B08B 7/00 B08B 17/00 C03C 23/00

Claims (2)

(57) [Claims] 1. A substrate having a surface coated with a water-soluble salt to form a water-soluble salt film which dissolves and desorbs in water, wherein the water-soluble salt is carbonate, bicarbonate, nitrate, phosphorus A substrate coated with a water-soluble salt, which is at least one selected from the group consisting of acid salts, silicates, borates and double salts thereof. 2. The water-soluble salt is sodium tripolyphosphate,
The water-soluble salt according to claim 1, which is at least one selected from the group consisting of sodium sesquicarbonate, sodium bicarbonate, sodium carbonate, sodium tetraborate and potassium tetraborate, and wherein the substrate is glass. Coated substrate.