JPH08234153A - Method for reproducing glass for color filter - Google Patents

Abstract

PURPOSE: To industrially advantageously peel colored coating films and to enable the reproduction of glass substrates having colored coating films by treating these glass substrates with an aq. compsn. contg. surfactants, chelate agents and alkalis. CONSTITUTION: The aq. compsn. is prepd. by mixing at least one kind of the surfactants selected from a group of nonionic surfactants and anionic surfactants, the chelate agents and the alkalis with water. Polyoxyethylene alkyl ethers, etc., are exemplified as the nonionic surfactants. The carboxylates expressed by formulas RCOOM, RCONHC2 H4 OCH2 COOM, ROOCNHCH2 COOM (where, R denotes 8 to 22 alkyl group, M denotes alkaline metals, such as sodium and potassiun), etc., are exemplified as the anionic surfactants. Ethylene diamines, etc., are exemplified as the chelate agents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling a glass substrate for a color filter. More specifically, the present invention provides
The present invention relates to a method of reclaiming a glass substrate for a color filter by peeling off the entire colored coating film formed when the colored coating film formed on the substrate has a defect.

[0002]

2. Description of the Related Art Color LCDs have been used for so-called pocket TVs and the like, but in recent years, their size and screen have been rapidly increased. In terms of image quality, the development of active driving elements represented by STN liquid crystal and TFT from TN liquid crystal has been developed to approach CRT.

Color filters used in such color LCDs are currently used in dyeing methods, pigment dispersion methods, electrodeposition methods,
Although it is manufactured by a method such as a printing method, various studies have been conducted on improvement in image quality and productivity in any method. In particular, in recent years, the demand for higher reliability and the demand for higher-precision color filters have led to stricter product inspections, leading to higher product failure rates, which has led to the production of color filters. The current situation is that the yield is decreasing.

In the production of color filters, defects occur in the colored coating film formed on the glass substrate due to various causes. For example, defects due to mixing of foreign substances such as dust, defects due to pinholes or chips, defects of unevenness (flatness failure), defects due to coloring other than a predetermined color, and the like are caused by various causes. This is one of the reasons for increasing the defect rate. Although it may be possible to eliminate all causes of defects by thoroughly controlling the manufacturing process, it is not always industrially advantageous, so various methods for correcting defects in the colored coating film that have arisen have been proposed. There is.

For example, in Japanese Patent Laid-Open No. 3-296701, a defective portion caused by a pinhole or a chip is
If the coating film is the same color as the colored coating film or has multiple defective coating films, apply a negative photosensitive resin containing a gray pigment,
A method of correcting by exposing and developing from the back of the coated surface has been proposed. Further, according to the same publication, JP-A-63-128302 proposes a method of applying a black negative photosensitive resin for forming a black matrix to a defective portion and correcting it by the same method. It is described that this method has a problem that a pinhole portion is recognized as a black defect particularly when a still image is displayed.

Further, Japanese Patent Application Laid-Open No. 4-369604 discloses a method of correcting a defect caused by mixing foreign matter such as dust. That is, a protective film made of a material with good peelability and flexibility is formed on the coating film including such a defective portion, the defective portion is irradiated with a laser beam to remove the portion, and the removed portion is removed. A heat- or photo-curable light-shielding material of the same color as the colored coating film is applied, the protective film around the defective part is mechanically peeled off, and then the light-shielding material is cured by heat or ultraviolet rays to try to correct it. Is.

The inventors of the present invention have made various investigations on the improvement in the yield of color filter production. However, even if there is a defect that cannot be corrected by the above-mentioned correction method, or even if it can be corrected, it is not necessarily industrially efficient. Since there is something that can not be said, when changing the viewpoint completely, when the colored coating film has a defect, peel off the entire colored coating film formed on the substrate and regenerate the color filter glass substrate, For the method of forming a colored coating film, in particular, as a result of earnestly examining the method of peeling a colored coating film industrially advantageous,
The present invention has been completed.

[0008]

The present invention provides a glass substrate having a colored coating film on its surface, at least one surfactant and a chelating agent selected from the group consisting of nonionic surfactants and anionic surfactants. Also provided is a method for reclaiming a glass substrate for a color filter, which comprises peeling off the colored coating film by treating with an aqueous composition containing an alkali.

The present invention will be described in detail below. The aqueous composition used in the method of the present invention can be prepared by mixing at least one surfactant selected from the group consisting of nonionic surfactants and anionic surfactants, a chelating agent and an alkali with water. . Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl thioethers, polyoxyethylene polyoxypropylene condensates, sorbitan alkyl esters, fatty acid ethanolamides, higher grades. Examples thereof include alkyl ethers. Among these, polyoxyethylene-based ones are preferable, and alkyl allyl ethers thereof are particularly preferable.

Anionic surfactants are represented by the formula RCOO
M, RCONHC ₂ H ₄ OCH ₂ COOM, ROOCN
HCH ₂ COOM (in the formula, R represents an alkyl group having 8 to 22 carbon atoms, M represents an alkali metal such as sodium or potassium), carboxylic acid salts, higher alcohol sulfuric acid ester salts, alkylallyl sulfonic acid salts,
Examples thereof include polyoxyethylene alkyl ether sulfate ester salts and polyoxyethylene alkyl allyl ether sulfate ester salts. Of these, alkylallyl sulfonates are most preferred.

As the chelating agent, ethylenediamine,
Amine compounds such as diethylenetriamine and pentaethylenehexamine, carboxylic acid compounds such as iminodiacetic acid, N-hydroxyethyliminodiacetic acid, ethylenediaminetetraacetic acid, trimethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid and ethylenediaminedipropiondiacetic acid, or those And a hetero compound such as pyridine, terpyridine, and 8-hydroxyquinoline. Among these, carboxylic acid compounds such as ethylenediaminetetraacetic acid, trimethylenediaminetetraacetic acid and ethylenediaminetetrapropionic acid or salts thereof are particularly suitable. The alkali is not particularly limited, but alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferably used.

The method for producing the aqueous composition used in the present invention is not particularly limited. For example, at least one of the above-mentioned nonionic surfactants, at least one of anionic surfactants, or a mixture thereof and a chelating agent are used. It can be produced by mixing with water so that the total solid content concentration becomes 10 to 40% by weight, and then adjusting the pH to about 9 to 11 using the above alkali. Here, the mixing ratio of the surfactant and the chelating agent can be appropriately determined depending on the type and situation of the colored coating film on the glass substrate to be treated, and is not particularly limited, but usually the surfactant The chelating agent can be appropriately selected from the range of 1 to 100 parts by weight with respect to 100 parts by weight of the agent. Further, it is desirable to use a mixture of a nonionic surfactant and an anionic surfactant depending on the type and situation of the colored coating film on the glass substrate, but the mixing ratio in this case is appropriately determined depending on the type and situation of the colored coating film. You can decide.

In the present invention, the aqueous composition thus prepared is used to remove the colored coating film formed on the glass substrate. The treatment method is not particularly limited, but it is industrially advantageous and can be efficiently performed by the following method.

The above aqueous composition has a total solid content of 1 to
It is dissolved in water to obtain a treatment liquid so as to be 5% by weight. On the other hand, for example, a glass substrate having a colored coating film is set in a predetermined cassette to be prepared, and the glass substrate is immersed in the treatment liquid. The treatment temperature is preferably 20 to 60 ° C., more preferably 30 to 50 ° C., the treatment time is 1 to 60 minutes,
Usually, several minutes to 30 minutes is sufficient. After the treatment, the glass substrate is pulled out from the treatment liquid, sufficiently washed with running water, and then the glass substrate is drained through an air knife or the like.

Although the colored coating film formed on the glass substrate can be peeled off in this manner, the glass substrate treated as described above is washed with running water and then immersed again in the above treatment liquid at room temperature for several hours. Time to 10 hours, for example, according to the production time cycle of the color filter, it is left to stand at night, and the next day, it is pulled out of the treatment liquid, subjected to the above-mentioned post-treatment and drained, and then given a predetermined colored coating film. The colored coating film can be more completely peeled off by a method such as being used in the step of forming.

On the glass substrate which has been subjected to the peeling treatment by the method of the present invention, the colored coating film is peeled off without damage to the surface by the peeling treatment, and the treatment liquid of the present invention also has a glass cleaning effect. Dust and dirt that may be present on the glass substrate, as well as stains and unevenness are removed and cleaned, which is sufficient for use in the production of color filters, and any of those conventionally known using it. A desired color filter can also be manufactured by the method of.
Since the method of the present invention does not have any adverse effect on the transparent conductive material such as ITO, it is possible to remove the colored coating film formed by the electrodeposition method on the transparent conductive layer formed on the glass substrate. Especially useful.

[0017]

EXAMPLES The present invention will be described in more detail below with reference to examples. This example illustrates one example of the method of the present invention and does not limit the present invention.

EXAMPLE A glass substrate having a length of 350 cm, a width of 300 cm, and a thickness of 1.1 mm on which an ITO circuit is formed at a predetermined pitch on the surface is used, and R (red) and G (green) are formed by a known electrodeposition method. ) And B (blue) colored coatings on the circuit and then 100
Baking treatment was performed at 15 ° C. for 15 minutes. On the other hand, Emulgen 91
0 (polyoxyethylene alkylphenyl ether-based nonionic surfactant, manufactured by Kao) 100 parts by weight and CHIREST 4K (ethylenediaminetetraacetate-based chelating agent, manufactured by CREST) 5 parts by weight have a solid content of 30% by weight.
Mixed with pure water so that the pH becomes 10 with caustic potash.
Was prepared as an aqueous composition.

This aqueous composition was diluted 10 times by weight with pure water to prepare a treatment liquid, and the glass substrate having the above R, G, B colored coating films was immersed in this treatment liquid, and the treatment was carried out at 45 ° C. for 30 minutes. I let it stand. Then, the glass substrate was pulled up and thoroughly washed with running water, and then the glass substrate was immersed in the above treatment liquid and left at room temperature overnight. The next morning, the glass substrate was pulled up, thoroughly washed with running water, and the substrate was drained through an air knife. The glass substrate treated in this manner has R,
The colored coating films of both G and B were completely peeled off, the surface was clean, and neither the glass surface nor the ITO circuit surface was damaged at all.

[0020]

Industrial Applicability According to the method of the present invention, the glass substrate for color filters can be regenerated by industrially advantageously peeling off the colored coating film formed thereon without damaging the glass substrate or the like, and It is possible to industrially advantageously clean and remove dust and dirt that may be present, as well as stains and unevenness, to clean the surface, and improve the yield of color filter production.

Claims (3)

[Claims] 1. A glass substrate having a colored coating film on its surface,
The colored coating film is peeled off by treatment with an aqueous composition containing at least one surfactant selected from the group consisting of nonionic surfactants and anionic surfactants, a chelating agent and an alkali. A method for recycling a glass substrate for a color filter, which is characterized in that 2. A glass substrate having a colored coating film on its surface,
The method according to claim 1, wherein the treatment is carried out by immersing in the aqueous composition maintained at 20 to 60 ° C. 3. The colored coating film is formed on a transparent conductive layer formed on a glass substrate by an electrodeposition method.
Or the method described in 2.