JP2002179438A - Method of exfoliating picture element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of exfoliating picture elements, by which the picture elements of a recovered or off-grade color filter can be easily exfoliated in a short time without giving a damage on a glass substrate, and the glass substrate can be regenerated and reused. SOLUTION: The method of exfoliating the picture elements on the glass substrate comprises a process for previously treating the picture elements with a pretreatment liquid containing an inorganic acid and a process for post- treating the picture elements with an exfoliation liquid containing an alkali.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing colored pixels (hereinafter simply referred to as "pixels"), and more particularly, to a method for removing a pixel formed on a glass substrate of a color filter such as a liquid crystal display by damaging the glass substrate. The present invention relates to a method for peeling pixels which can be easily peeled without performing.

[0002]

2. Description of the Related Art Conventionally, a color filter is formed by forming RGB pixels by a photolithography method using a colored photosensitive resin on a glass substrate. If any of these pixels does not meet the quality standards in the color filter manufacturing process, peel off the pixel to regenerate the glass substrate from the color filter and reuse it in the color filter manufacturing process. It is desirable to do. Further, there is a demand for collecting a color filter from various used electric appliances having a color filter, peeling pixels from the color filter, regenerating a glass substrate, and similarly reusing the glass substrate.

[0003] The pixels on the glass substrate are generally removed by a peeling method such as immersion or spraying using an alkaline peeling solution. However, in the method of peeling pixels using these alkaline peeling liquids, since the glass surface is exposed at the time of peeling, the peeling liquid reacts with the glass substrate, and the glass surface becomes white. Burns, bluish burns, etc. appear, and latent scratches appear on the glass surface due to minute scratches. A glass substrate that has exhibited such damage cannot be reused as a glass substrate for a color filter.

[0004] The colored photosensitive resin constituting the pixel is:
Depending on the application and the required performance, UV curable resins such as novolak type and acrylic type, polyvinyl cinnamate type, cyclized rubber-bisazide type, unsaturated polyester type, epoxy type, silicone type etc. It is made of various curable resins such as a mold resin, an X-ray curable resin, and a thermosetting resin. Therefore, when peeling the pixel from the glass substrate, an alkaline peeling liquid must be prepared according to the type of the pixel. In addition, when a pixel to which an overcoat material is applied to protect a pixel is peeled, the layer thickness of the entire pixel including the overcoat material is increased, so that the pixel peel time becomes longer, and Peeling is not enough. As described above, depending on the type of the pixel, the overcoat material, and the like, it is necessary to change the peeling conditions such as the peeling time and the peeling temperature, the peeling process, and the preparation of the pixel peeling solution. The change also tended to increase the damage to the glass substrate.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the recovered or defective pixel of the color filter is easily peeled in a short time without damaging the glass substrate as described above. It is an object of the present invention to provide a method for separating a pixel which can be reproduced and reused.

[0006]

The above objects are achieved by the present invention described below. That is, the present invention provides a method for separating pixels on a glass substrate, comprising a step of pre-treating with a pre-treatment liquid containing an inorganic acid and a step of post-treating with a stripping liquid containing an alkali. provide.

The inventor of the present invention has conducted intensive studies in order to solve the above-mentioned problems. As a result, the above-mentioned pixel peeling method has revealed that various types of photosensitive colored resins on a glass substrate of a recovered or defective color filter are used. When peeling the pixel consisting of
It has been found that this is a pixel peeling method that can easily peel a pixel in a short time without damaging a glass substrate using a known peeling solution containing an alkali.

[0008]

Next, the present invention will be described in more detail with reference to preferred embodiments. The pre-treatment step in the peeling method of the present invention includes swelling, cracking, porosity, and partial dissolution of the above-mentioned various pixels and pixels to which an overcoat material that protects the pixel surface is applied using a pre-treatment liquid. This is performed in order to cause damage such as the above and to facilitate the peeling of the pixel in a later process. The pretreatment liquid to be used is an inorganic acid alone or a treatment liquid obtained by adding an oxidizing agent to the inorganic acid.

Examples of the inorganic acid include sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and the like, and a mixture thereof. Preferred inorganic acids include 98% by weight concentrated sulfuric acid.

As the oxidizing agent, H ₂ O ₂ , Na ₂ O ₂ , Ba
O ₂ , inorganic and organic peroxides such as (C ₆ H ₅ CO) ₂ O ₂ , sodium perborate (sodium peroxoborate), Na ₂ S ₂ O ₈ (sodium persulfate), HC
_{O 3 H, C 6 H 5} CO 3 H, peroxo acids, such as CF ₃ CO ₃ H _{(salt), HIO 4, Na 3 H} 2 IO 6, oxyacids such as KIO ₄ (salt), over such HMnO ₄ Manganese acid (salt), C
oxides such as eO ₂ , metal salts such as FeCl ₃ , HN
Nitric compounds such as O ₃ , N ₂ O ₄ and N ₂ O _3, and metal salts thereof;
Nitrogen oxides, ozone, and the like, and mixtures thereof. Preferred oxidizing agents include hydrogen peroxide, sodium perborate, sodium peroxide, sodium persulfate and the like. Particularly preferred oxidizing agents include sodium persulfate.

As the pretreatment liquid, the above-mentioned inorganic acid alone can be used, but preferably a mixture of the above-mentioned inorganic acid and an oxidizing agent is used. When the above oxidizing agent is used in combination, the inorganic acid 1
The oxidizing agent is used in an amount of 2 to 20 parts by weight, preferably 5 to 15 parts by weight, based on 00 parts by weight. When the mixing ratio of the oxidizing agent exceeds the upper limit, there is a problem that the damage effect of the pretreatment liquid on the pixels is reduced. However, there is a problem that the processing effect decreases with the passage of time. Preferred pretreatment liquids include 98% by weight concentrated sulfuric acid alone or a mixture of an inorganic acid and sodium persulfate. Also, if necessary, as a wettability improver for pixels,
Surfactants and the like can be added. The pretreatment liquid can be used alone or diluted with water (50 to 90% by weight). The dilution concentration of the pretreatment solution may be selected depending on the type of the pixel to be damaged.

As the stripping solution containing an alkali used for stripping the pixels in the subsequent step, a known stripping solution used for stripping pixels can be used. Examples of the alkali include hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal salts such as sodium bicarbonate; alkali metal phosphates such as sodium tribasic phosphate and sodium dibasic phosphate; Alkali metals such as sodium silicate and sodium tripolyphosphate; alkalis such as sodium orthosilicate and sodium metasilicate; and mixtures thereof. Preferably, an aqueous sodium hydroxide solution (10% by weight) is used. In addition, a stripper containing an organic alkali such as an organic amine can also be used.

Further, the above-mentioned stripping solution obtained by adding an additive thereto can also be used. As additives, for example, polycarboxylic acid ammonium salt, polyoxyalkylene alkyl ether, other anionic, nonionic, cationic, amphoteric surfactants and other surfactants, ethylenediaminetetraacetic acid, hard water softening such as metaphosphoric acid Examples of the agent include chelating agents and organic solvents such as ethylene glycol, propylene glycol, and isopropyl alcohol.

The organic stripping solution includes a stripping solution comprising an amine, a glycol monoalkyl ether, a sugar alcohol and water. Examples of the amine include monoethanolamine, triethanolamine, diethanolamine, diethylaminoethanol and the like. Examples thereof include alkanolamine, alkanolamine, alkoxyalkylamine and alkoxyalkanolamine. Further, an organic amine-based stripping solution such as a stripping solution composed of an alkanolalkoxyalkylamine or an alkoxyalkanolamine, a glycol monoalkyl ether, a sugar alcohol, a quaternary ammonium hydroxide, and water may be used.

In the method of peeling pixels according to the present invention, the pretreatment liquid is heated to room temperature to 70 ° C., preferably 50 to 60 ° C.
The color filter recovered in the pretreatment liquid is used for 20 to 3
Immersion for 0 minutes causes damage such as swelling, cracks, porosity, partial dissolution, etc. to the pixels on the glass substrate. Next, the pixel is washed with water. After the cleaning, the pretreated pixels are exposed to an alkali-containing stripper at room temperature to 70 ° C. for 20 to 3 times by dipping or spraying.
Applying for 0 minutes, the pre-processed pixels on the glass substrate can be peeled off and washed with water to recover the glass substrate for the color filter. Note that the pretreatment condition and the peeling condition can be appropriately selected depending on the type of the pixel used.

The peeling method of the present invention can be applied to an electron beam such as an ultraviolet curable resin such as a novolak type or an acrylic type, a polyvinyl cinnamate type, a cyclized rubber-bisazide type, an unsaturated polyester type, an epoxy type or a silicone type. It can be used for various colored photosensitive resins such as a curable resin, an X-ray curable resin, and a thermosetting resin, and for a pixel to which a transparent overcoating agent made of the photosensitive resin has been applied.

As described above, the method of peeling a pixel according to the present invention does not require the use of a conventional peeling liquid for various pixels, and damages the pixel by pretreatment,
Since the pixels can be peeled off easily and without damage to the glass substrate in a short time with a normal peeling liquid, the range of the peeling effect for various pixels is expanded, and the glass substrate is removed from the collected or defective color filters. Can be quickly and easily recovered, and the glass substrate can be recycled and reused.

[0018]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In addition, "part" or "%" in the text
There is a weight basis. Example 1 An acrylic negative colored photosensitive resin was applied to a glass substrate for a color filter to a thickness of 0.5 μm to 1.5 μm (solid content), and a colored photosensitive resin film was formed using an ultra-high pressure mercury lamp. Was cured by ultraviolet rays to form pixels. The glass substrate on which the pixels are formed is immersed in 98% concentrated sulfuric acid heated to 50 to 60 ° C. for 20 to 30 minutes.
The pixels were peeled by immersion in a peeling solution, which was a caustic soda aqueous solution (10%) heated to 0 to 70 ° C., for 20 to 30 minutes, and after peeling, the pixels were washed with water to peel off the pixels on the glass substrate.

Example 2 An acrylic negative colored photosensitive resin having a thickness of 0.5 μm to 1.5 μm (solid content) was applied to a glass substrate for a color filter, and the colored photosensitive resin was applied using an ultra-high pressure mercury lamp. The pixel was formed by curing the conductive resin film with ultraviolet rays. The glass substrate on which the pixels were formed was mixed with 50 parts of a pretreatment liquid prepared by mixing 100 parts of 98% concentrated sulfuric acid and 10 parts of sodium persulfate.
To 60 ° C., and place the glass substrate in the treatment solution for 20 to 3 minutes.
Immersion for 0 minutes, immersion, water washing, and then to a stripping solution of caustic soda aqueous solution (10%) heated to 60 to 70 ° C.
The pixel was peeled by immersion for 0 to 30 minutes, and after the peeling, the pixel on the glass substrate was peeled off by washing with water.

Example 3 A novolak-type negative colored photosensitive resin was applied to a glass substrate for a color filter in an amount of 0.5 μm to 1.5 μm (solid content).
Then, the colored photosensitive resin film was cured with an ultraviolet ray using an ultrahigh pressure mercury lamp to form a pixel. The glass substrate on which the pixels were formed was mixed with a pretreatment liquid prepared by mixing 100 parts of 98% concentrated sulfuric acid and 10 parts of sodium persulfate.
0 to 60 ° C., and the glass substrate is placed in the treatment liquid for 20 to 60 ° C.
Immerse for 30 minutes, wash with water after immersion, then 60-70 ° C
The stripping solution, which is an aqueous caustic potassium solution (10%) heated to 2
The pixel was peeled by immersion for 0 to 30 minutes, and after the peeling, the pixel on the glass substrate was peeled off by washing with water.

Comparative Example 1 An acrylic negative colored photosensitive resin having a film thickness of 0.5 μm to 1.5 μm (solid content) was applied to a glass substrate for a color filter, and colored with a super-high pressure mercury lamp. The pixel was formed by curing the conductive resin film with ultraviolet rays. The glass substrate on which these pixels are formed is not treated with a pretreatment liquid,
A caustic soda aqueous solution (10
%), The pixels were peeled off by immersion in a peeling liquid for 20 to 30 minutes. After the peeling, the pixels on the glass substrate were peeled off by washing with water.

Comparative Example 2 A novolak type negative colored photosensitive resin was applied to a glass substrate for a color filter in an amount of 0.5 μm to 1.5 μm (solid content).
Then, the colored photosensitive resin film was cured with an ultraviolet ray using an ultrahigh pressure mercury lamp to form a pixel. The glass substrate on which the pixels were formed was immediately heated to 60 to 70 ° C. without being treated with a pretreatment solution,
(0%) was immersed in a stripping solution for 20 to 30 minutes to peel off the pixels. After the peeling, the pixels on the glass substrate were peeled off by washing with water. Each of the above glass substrates was collected, and the peelability of pixels on each glass substrate and the degree of damage to the glass substrate surface were evaluated according to the following criteria. Table 1 shows the evaluation results.

(Peel-off property of pixel) Evaluation point A: No trace of pixel is observed on the surface of the glass substrate. ×: Slight traces of pixels are observed on the surface of the glass substrate.

(Damage degree of glass substrate surface) Evaluation point ：: No latent scratch, cloudiness, white blur, blue blur, etc. were observed on the surface of the glass substrate. ×: Latent scratches, fogging, white blurring, blue blurring, etc. are observed on the surface of the glass substrate.

[0025]

[0026]

According to the method of peeling a pixel of the present invention, it is not necessary to prepare a peeling liquid for various pixels as in the prior art.
The pixels are damaged by the pre-treatment, and the pixels can be easily peeled in a short time using a normal peeling liquid without damaging the glass substrate. Therefore, the range of the peeling effect for various pixels is widened, the glass substrate can be quickly and easily collected from the collected color filters, and the glass substrate can be recycled and reused.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 505 B09B 3/00 304J F-term (Reference) 2H088 FA23 HA12 2H090 JB02 JC19 JC20 LA01 2H091 FA02Y FC14 LA09 4D004 AA07 AA18 BA10 CA22 CA34 CC11 CC12 CC20 DA03 DA06 DA10 4G059 AA08 AB01 AB05 AC30 BB04 BB12

Claims (7)

[Claims] 1. A method for stripping pixels on a glass substrate, comprising: a step of pre-treating with a pre-treatment liquid containing an inorganic acid; and a step of post-treating with a stripping liquid containing an alkali. 2. The method according to claim 1, wherein the pretreatment liquid further contains an oxidizing agent. 3. The method according to claim 2, wherein the pretreatment liquid contains 2 to 10 parts by weight of an oxidizing agent based on 100 parts by weight of the inorganic acid. 4. The method according to claim 1, wherein the inorganic acid is 98% by weight concentrated sulfuric acid. 5. The method according to claim 2, wherein the oxidizing agent is sodium persulfate. 6. The method for stripping pixels according to claim 1, wherein the pretreatment is performed at a normal temperature to 70 ° C. for pretreatment. 7. A pretreatment liquid used in the method for stripping pixels according to claim 1.