KR20220157931A - Manufacturing method of glass plate - Google Patents

Abstract

The cleaning step (S2) in the glass plate manufacturing method comprising a storage step of storing the glass plate in contact with the resin sheet and a washing step of washing the glass plate after the storage step is to apply the first cleaning liquid (CS1) to the glass plate (G). ) and a first cleaning step (S21) of cleaning the glass plate G by supplying a second cleaning liquid (CS2) to the glass plate G after the first cleaning step (S21) to clean the glass plate G. 2 cleaning process (S23) is provided. The first cleaning liquid CS1 is an acidic cleaning liquid, and the second cleaning liquid CS2 is an alkaline cleaning liquid.

Description

Manufacturing method of glass plate

The present invention relates to a method for manufacturing a glass sheet.

In recent years, panel displays such as liquid crystal displays and organic EL displays have been promoted to achieve higher definition. In accordance with this, a precise electric circuit is formed on a glass plate used as a substrate for a display in the manufacturing process of the display. Therefore, this type of glass plate is required to have high cleanliness, free from adhering dust and dirt.

The manufacturing process of a glass plate is, for example, an unpacking step of taking out a glass original plate stored on a pallet, a cutting step of cutting out a glass plate of a predetermined size from the extracted glass original plate, and an end surface processing step of performing edge processing on a glass plate, , and a cleaning process for cleaning the glass plate processed at the end surface. As a method of cleaning a glass plate, a method of cleaning a glass plate conveyed in a predetermined direction by a cleaning tool such as a cleaning disk or a cleaning brush (roll brush) is exemplified (see Patent Document 1, for example).

Japanese Patent Laid-Open No. 2017-14060

The glass original plates supplied to the manufacturing process of the said glass plate are stacked and stored on a pallet, and a some glass original plate may be laminated|stacked with the resin sheet interposed on a pallet.

In this case, if the storage on the pallet is extended for a long period of time, calcium contamination or contamination containing organic matter may occur. In addition, there are cases where these stains are firmly adhered to the glass original plate, and it is difficult to remove them from the glass plate in the cleaning step.

Then, this invention makes it a technical subject to improve the cleaning power in the cleaning process of a glass plate.

This invention is for solving the said subject, and it is the manufacturing method of the glass plate provided with the storage process of storing the glass plate which contacts a resin sheet, and the washing process of washing the said glass plate after the said storage process, The said washing process is the said glass plate a first cleaning step of cleaning the glass plate by supplying a first cleaning solution thereto, and a second cleaning step of cleaning the glass plate by supplying a second cleaning solution to the glass plate after the first cleaning step; is an acidic cleaning solution, and the second cleaning solution is an alkaline cleaning solution.

According to intensive research by the present inventors, when the resin sheet is kept in contact with the glass sheet for a long period of time, calcium is contained in the stain transferred from the resin sheet to the surface of the glass plate (hereinafter referred to as "calcium stain"). Compared to staining, it has been confirmed that it is difficult to remove the calcium stain from the glass plate by washing.

The present inventors have found that calcium contamination and contamination containing organic matter can be effectively removed from a glass plate by performing a second cleaning process in which an acidic cleaning liquid is used as the first cleaning liquid and then a second cleaning process in which an alkaline cleaning liquid is used as the second cleaning liquid. found something

The acidic washing liquid may contain a hydroxy acid. As a hydroxy acid (oxyacid), glycolic acid, lactic acid, tartaric acid, citric acid, malic acid, salicylic acid etc. are mentioned, for example. A hydroxy acid is a carboxylic acid having both a hydroxyl group and is highly water-soluble. In addition, since the carboxyl group contained in the hydroxy acid molecule reacts with the calcium ion (Ca ²⁺ ) of the calcium contamination on the surface of the glass plate by a chelating effect, ^and introduces the calcium ion into one molecule or into multiple molecules to stabilize it. It is effective in removing calcium components adhering to the surface of the glass plate.

The alkaline washing liquid may contain a hydroxide salt, and may contain, for example, at least one of sodium hydroxide and potassium hydroxide.

In the first cleaning step, the glass plate may be washed by bringing a cleaning tool into contact with the glass plate. In this way, the first cleaning process can be performed efficiently.

In the second cleaning step, the glass plate may be washed by bringing a cleaning tool into contact with the glass plate. In this way, the second cleaning process can be performed efficiently.

The method includes, after the first cleaning step and before the second cleaning step, a liquid removing step of removing the first cleaning liquid adhering to the glass plate by supplying a removing liquid to the glass plate, wherein the removing liquid may be warm water. . By removing the first cleaning liquid adhering to the glass plate after the first cleaning process in this liquid removal step, the glass plate can be cleaned more effectively with the second cleaning liquid in the subsequent second cleaning process.

The method includes a rinsing step of removing the second cleaning liquid adhering to the glass plate by supplying a rinsing liquid to the glass plate after the second washing process, and the rinsing liquid may contain alkaline electrolyzed water. By covering the surface of the glass plate with negative ions in the rinsing step, it is possible to prevent reattachment of particulate matter present dispersed in the rinsing liquid to the surface of the glass plate, and to increase the cleanliness of the surface of the glass plate after the rinsing step. have.

(Effects of the Invention)

ADVANTAGE OF THE INVENTION According to this invention, the cleaning power in the cleaning process of a glass plate can be improved.

1 is a cross-sectional view showing a method for manufacturing a glass plate according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view showing a configuration of a cleaner in a first cleaning unit and a second cleaning unit.
3 is a flow chart showing a cleaning process.
Fig. 4 is a cross-sectional view showing a method for manufacturing a glass plate according to a second embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated, referring drawings. 1-3 show the 1st embodiment of the manufacturing method of the glass plate by this invention.

As shown in FIG. 1, this method is provided with the storage process (S1) which stores glass plate G, and the washing|cleaning process (S2) which wash|cleans glass plate G. Between the storage step (S1) and the cleaning step (S2), the above-described unpacking step, the cutting step, and the end surface processing step may be further provided. As a post-process of washing|cleaning process S2, you may further equip the inspection process of glass plate G and the packing process which mounts glass plate G on a pallet.

In storage process S1, glass plate G is managed in the state of the package PB. The package PB is comprised by mounting several glass plate G on the pallet P. In storage process (S1) of this embodiment, although glass plate G is stored in a horizontal arrangement posture, glass plate G may be stored in an inclined posture.

Glass plate G is comprised by cutting|disconnecting the long picture-shaped glass ribbon formed by the overflow down-draw method, for example. In the overflow down-draw method, molten glass is poured into an overflow groove formed in the upper part of a molded body having a substantially wedge-shaped cross section, and the molten glass flowing out of the overflow groove on both sides flows down along the sidewalls on both sides of the molded body, while lower end of the molded body fusion and integration, and continuous molding of the glass ribbon. Glass plate G is not limited to the overflow down-draw method, and may be manufactured by a float method or other various molding methods.

Although glass plate G is comprised in the rectangular shape, it is not limited to this shape. The glass plate G includes a first main surface Ga and a second main surface Gb. In this embodiment, the first main surface Ga is a guarantee surface, and the second main surface Gb is a non-guarantee surface. Here, "guaranteed surface" means the surface on the side where film formation processing, such as a transparent conductive film, is performed, for example in the manufacturing process of a display.

The glass plate G is, for example, silicate glass or silica glass, and is preferably made of borosilicate glass, soda lime glass, aluminosilicate glass, chemically strengthened glass or alkali free glass. Here, the alkali-free glass is a glass that does not substantially contain an alkali component (alkali metal oxide), and specifically, a glass having an alkali component weight ratio of 3000 ppm or less. The weight ratio of the alkali component in the present invention is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less.

The resin sheet RS is piled up on each glass plate G. Contact between glass plates G is prevented by this resin sheet RS in the state of package PB.

The resin sheet RS is constituted by a rectangular sheet having a larger surface area than the glass plate G. The resin sheet RS is constituted by, for example, a foamed resin sheet made of a resin containing polyethylene as a main component, a resin protective film, or the like. The resin sheet RS may contain an antistatic agent such as a polymer type antistatic agent or a surfactant such as an anionic surfactant or a nonionic surfactant.

In storage process (S1), package PB is stored for one year from several days, for example. As the storage period increases, contamination of the glass plate G increases, and the effect of improving the detergency of the present invention becomes remarkable. For this reason, the storage period is preferably 2 months or more, and more preferably 4 months or more. The package PB which passed through storage process S1 is carried out from storage space SS.

Glass plate G taken out from package PB is supplied to washing|cleaning process S2. In this case, resin sheet RS is peeled off from glass plate G. In washing process S2, glass plate G is washed with the washing apparatus 1 shown in FIG.

The cleaning device 1 includes a first cleaning unit 2 that cleans the glass plate G while supplying the first cleaning liquid CS1 to the glass plate G, and a first cleaning liquid CS1 attached to the glass plate G. ), the liquid removal unit 3 for removing the second cleaning liquid CS2, the second cleaning unit 4 for cleaning the glass plate G while supplying the second cleaning liquid CS2 to the glass plate G, and the rinse liquid for the glass plate G A rinsing unit 5 for removing the second cleaning liquid CS2 adhering to the glass plate G while supplying the glass plate G, and a drying unit 6 are mainly provided. In addition, the cleaning apparatus 1 is equipped with the conveying apparatus 7 which conveys the glass plate G along the predetermined conveyance direction X.

The first cleaning unit 2 includes an upper cleaner 2a that cleans the first main surface Ga of the glass plate G and a lower cleaner 2b that cleans the second main surface Gb of the glass plate G. do.

The upper cleaner 2a includes an upper cleaner 8a contacting the first main surface Ga, and a main body 9a supporting the upper cleaner 8a. The lower cleaner 2b includes a lower cleaner 8b contacting the second main surface Gb and a main body 9b supporting the lower cleaner 8b. The upper scrubber 2a and the lower scrubber 2b are of the same type.

Hereinafter, the configuration of each washer 2a, 2b will be described using the upper washer 2a shown in FIG. 2 as an example. The upper cleaning port 8a is configured in a disc shape, but is not limited to this shape. The upper cleaning tool 8a includes a cleaning member 10 that contacts the first main surface Ga of the glass plate G, and a shaft portion 11 that supports the cleaning member 10 .

The cleaning member 10 is formed into a disc shape (disc shape) by, for example, a foamed resin molded body or foamed rubber molded body (foam sponge), or a felt-like fiber molded body (felt sponge). Not limited to this configuration, the cleaning member 10 may be configured with a brush.

The cleaning member 10 has a supply hole 12 through which the first cleaning liquid CS1 is supplied to the glass plate G. The shaft portion 11 is configured in a tubular shape, and the first cleaning liquid CS1 can pass therein. The shaft portion 11 communicates with the supply hole 12 of the cleaning member 10 .

The body portion 9a includes a storage tank 13 for storing the first cleaning liquid CS1, a bearing portion 14 for rotatably supporting the shaft portion 11 of the first cleaning tool, and a drive unit for rotating the shaft portion 11. (not shown).

The storage tank 13 stores acidic cleaning liquid as the first cleaning liquid CS1. The acidic washing liquid is composed of, for example, an aqueous solution containing a hydroxy acid. As a hydroxy acid, glycolic acid, lactic acid, tartaric acid, citric acid, malic acid, salicylic acid etc. are mentioned, for example. A hydroxy acid is a carboxylic acid having both a hydroxyl group and is highly water-soluble. In addition, in the hydroxy acid, the carboxyl group contained in the molecule reacts with the calcium ^{ion (Ca 2+ )} of the calcium contamination on the surface of the glass plate G (each main surface (Ga, Gb)) by a chelating effect, and the calcium ion It is effective in removing the calcium component adhered to each main surface (Ga, Gb) of the glass plate (G) because it is stabilized by introducing into one molecule or in a plurality of molecules. For example, when glycolic acid is used as an acidic cleaning liquid, the concentration is preferably 1.5 to 10%, but is not limited to this range. In addition, the acidic washing liquid may contain one or more hydroxy acids.

In addition to this, the first cleaning liquid CS1 may also contain a surfactant for washing and removing stains including organic substances on the glass plate G. As the surfactant, it can be selected from the group consisting of anionic surfactants represented by sodium alkylbenzenesulfonate and the like and nonionic surfactants represented by polyoxyethylene alkyl ether and the like. The surfactant is effective in introducing and removing organic matter-maintenance stains among the stains transferred from the resin sheet RS to the respective main surfaces Ga and Gb of the glass plate G and removing them from the respective main surfaces Ga and Gb of the glass plate G. to be.

The acidic cleaning liquid further contains a chelating agent that preferentially supplements calcium ions in order to prevent redeposition of calcium ^{ions (Ca 2+ )} freed in the cleaning liquid to each main surface (Ga, Gb) of the glass plate (G). may include As the chelate aid to be added, sodium tripolyphosphate, EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), sodium citrate, and various organic polymer chelate aids may be used. You may use an inorganic substance etc. which adsorb|suck.

The storage tank 13 may be provided with a heater for heating the first cleaning liquid CS1. In this case, the temperature of the first cleaning liquid CS1 is preferably 40 to 50°C, but is not limited to this range.

The first cleaning unit 2 rotates the shaft portion 11 by a driving unit in a state where the cleaning devices 8a and 8b are brought into contact with the main surfaces Ga and Gb of the glass sheet G, thereby cleaning the glass sheet G. Friction cleaning can be performed.

The liquid removal unit 3 is for removing the first cleaning liquid CS1 adhering to the glass plate G that has passed through the first cleaning unit 2 . The liquid removal unit 3 includes an upper air knife 3a and a lower air knife 3b. The liquid removal part 3 can remove the 1st cleaning liquid CS1 from the glass plate G by blowing air from each air knife 3a, 3b to each main surface Ga, Gb of the glass plate G.

The second cleaning unit 4 includes an upper cleaning unit 4a and a lower cleaning unit 4b capable of performing friction cleaning on the glass plate G. The upper washer 4a includes an upper washer 15a and a main body 16a supporting the upper washer 15a. The lower scrubber 4b includes a lower scrubber 15b and a main body 16b supporting the lower scrubber 15b. The upper cleaner 4a and the lower cleaner 4b of the second cleaner 4 have the same structure as the upper cleaner 2a and the lower cleaner 2b of the first cleaner 2 .

However, the second cleaning unit 4 is different from the first cleaning unit 2 in that an alkaline cleaning liquid is used as the second cleaning liquid CS2. The alkaline washing liquid contains a hydroxide salt and is constituted by, for example, an aqueous solution containing at least one of sodium hydroxide and potassium hydroxide. The total of the sodium hydroxide concentration and the potassium hydroxide concentration in the alkaline washing liquid is preferably 0.5 to 10%, more preferably 1.5 to 10%. The second cleaning liquid CS2 may contain a surfactant or a chelating agent. In addition, the temperature of the second cleaning liquid CS2 is preferably 40 to 50°C, but is not limited to this range.

The alkaline washing liquid is not limited to a hydroxide salt, and may also contain a carbonate salt. As the carbonate, sodium carbonate, potassium carbonate, sodium sesquicarbonate, sodium hydrogencarbonate (sodium bicarbonate) and the like can be used. In addition, it is not limited to the above, and the alkaline washing liquid may also contain alkali builder aids such as silicate.

Other contaminants including organic matter can be more effectively removed from the glass plate G by the alkaline cleaning solution. In addition, by alkalizing each main surface Ga, Gb of glass plate G to maintain negative electric charge, after using the first cleaning liquid CS1 (acidic detergent), each main surface Ga, Gb of glass plate G is adsorbed to each main surface Ga, Gb. It becomes possible to remove the highly polar surfactant component which remains especially effectively.

The alkaline cleaning solution may also contain a surfactant component for effectively removing dirt including organic matter on the glass plate G and the residue of the acidic cleaning agent. As the surfactant, it can be selected from the group consisting of anionic surfactants represented by sodium alkylbenzenesulfonate and the like and nonionic surfactants represented by polyoxyethylene alkyl ether and the like. The surfactant is effective for introducing and removing the organic substance main residues on the respective main surfaces Ga and Gb of the glass plate G and removing them from the respective main surfaces Ga and Gb of the glass plate G.

More preferably, the alkaline cleaning liquid is removed from the glass plate G, and the first cleaning liquid CS1 is used to prevent the calcium ions liberated in the alkaline cleaning liquid from reattaching to each of the main surfaces Ga and Gb of the glass plate G. Similarly, a chelating agent may be included.

The rinsing unit 5 is for removing the second cleaning liquid CS2 adhering to the glass plate G that has passed through the second cleaning unit 4 . The rinse unit 5 includes an upper rinse liquid supply unit 5a and a lower rinse liquid supply unit 5b. The upper rinse liquid supply unit 5a supplies the rinse liquid to the first main surface Ga of the glass plate G. The lower rinse liquid supply unit 5b supplies the rinse liquid to the second main surface Gb of the glass plate G.

As a rinse liquid, although pure water is used, for example, it is not limited to this. For example, pure water containing alkaline electrolyzed water having a pH of about 11 formed by electrolysis from a small-concentration potassium carbonate aqueous solution may be used as the rinse liquid. As a result, each main surface (Ga, Gb) of the glass plate G is negatively charged (covered with negative ions), and calcium ions, organic substances, particles, etc. dispersed in the drainage are negatively charged and have a repelling effect, thereby cleaning It is possible to prevent re-adherence of foreign matter to the main surfaces Ga and Gb of the glass plate G later, and is particularly effective in reducing minute particles not shown in the appearance inspection. When using pure water containing alkaline electrolyzed water, the pH of the pure water containing alkaline electrolyzed water may be, for example, 9 to 12.

The rinsing unit 5 is equipped with a spray nozzle, and can remove the second cleaning liquid CS from the glass plate G by spraying a high-pressure rinsing liquid for cleaning. The rinsing unit 5 may remove the second cleaning liquid CS2 from the glass plate G by spraying a rinsing liquid in which air is mixed into pure water using a mix jet nozzle. Further, the rinse unit 5 may remove the second cleaning liquid CS from the glass plate G using a cleaning tool.

The drying unit 6 is for removing the rinsing liquid adhering to the glass plate G that has passed through the rinsing unit 5 . The drying unit 6 includes an upper air knife 6a and a lower air knife 6b. The upper air knife 6a blows air onto the first main surface Ga of the glass plate G that has passed through the rinse unit 5 . The lower air knife 6b blows air to the second main surface Gb of the glass plate G.

The conveying device 7 conveys the glass plate G from the first cleaning part 2 to the drying part 6 . The conveying device 7 is configured by, for example, a roller conveyor, but is not limited to this configuration. The conveying device 7 has a plurality of conveying rollers 7a disposed at predetermined intervals. Each conveyance roller 7a conveys the said glass plate G along the conveyance direction X by being rotationally driven, contacting the 2nd main surface Gb of glass plate G.

As shown in FIG. 3, the cleaning step S2 includes a first cleaning step S21, a liquid removal step S22, a second washing step S23, a rinse step S24, and a drying step S25. to provide

In the first cleaning step (S21), upper cleaning in the first cleaning unit 2 is carried out while conveying the glass plate G along the transport direction X by the conveying device 7 in the first cleaning unit 2. The sphere 8a and the lower cleaning sphere 8b are brought into contact with the first main surface Ga and the second main surface Gb of the glass plate G. Thereby, glass plate G is clamped by each cleaning tool 8a, 8b. Each of the cleaning ports 8a and 8b rotates the cleaning member 10 while supplying an acidic cleaning liquid as the first cleaning liquid CS1 to each of the main surfaces Ga and Gb of the glass plate G. Thereby, the 1st main surface Ga and the 2nd main surface Gb of glass plate G are washed simultaneously.

In the liquid removal step (S22), the glass plate G passed through the first cleaning part 2 is blown with air from the air knives 3a and 3b of the liquid removal part 3, thereby removing the glass plate G The first cleaning liquid CS1 adhering to the first main surface Ga and the second main surface Gb is removed.

In the second cleaning step (S23), the upper cleaning port 15a and the lower side cleaning in the second cleaning unit 4 are carried while the glass plate G is transported along the transport direction X in the second cleaning unit 4. The sphere 15b is brought into contact with the first main surface Ga and the second main surface Gb of the glass plate G. Each of the cleaning ports 15a and 15b rotates the cleaning member 10 while supplying an alkaline cleaning liquid as the second cleaning liquid CS2 to each of the main surfaces Ga and Gb of the glass plate G. Thereby, the 1st main surface Ga and the 2nd main surface Gb of glass plate G are washed simultaneously.

In the rinsing step (S24), the rinsing liquid is supplied from each of the rinsing liquid supply units 5a and 5b of the rinsing unit 5 to the glass plate G that has passed through the second cleaning unit 4. As a result, the second cleaning liquid CS2 adhering to the first main surface Ga and the second main surface Gb of the glass plate G can be removed.

In the drying step (S25), air is blown from the respective air knives 6a and 6b of the drying section 6 with respect to the glass plate G that has passed through the rinsing section 5. In this case, it is preferable to blow high-pressure air toward the glass plate G from the air knives 6a and 6b, for example. Thereby, the rinse liquid adhering to glass plate G can be removed.

According to the manufacturing method of glass plate G by this embodiment, calcium contamination transferred from resin sheet RS to glass plate G in storage step S1 can be effectively removed by first cleaning step S21. have. Also, in the second cleaning process (S23), contamination containing organic matter can be effectively removed. It becomes possible to improve the cleaning power in cleaning process S2 of glass plate G by this. Here, calcium contamination is caused by a trace amount of calcium contained in the moisture in the air in the process where the additives (for example, polyethylene glycol or a copolymer of polyethylene glycol and polypropylene) included in the resin sheet RS absorb moisture in the air. It is presumed to be caused by precipitation and concentration and adhering to glass. Further, it is presumed that contamination with organic matter occurs when various additives (for example, hydrophobic substances) included in the resin sheet RS bleed out.

4 shows a second embodiment of a method for manufacturing a glass plate according to the present invention. In this embodiment, the configuration of the liquid removal step S22 is different from that of the first embodiment. In the first embodiment, the liquid removal unit 3 of the cleaning device 1 is constituted by an air knife, but the liquid removal unit 3 in the present embodiment is a first cleaning liquid attached to the glass plate G. It is constituted by a shower cleaning device that supplies a removal liquid to remove (CS1).

The liquid removal unit 3 includes an upper removal liquid supply unit 17a and a lower removal liquid supply unit 17b. The upper removal liquid supply unit 17a supplies the removal liquid to the first main surface Ga of the glass plate G. The lower removal liquid supply part 17b supplies the removal liquid to the second main surface Gb of the glass plate G.

The removal liquid supplied to glass plate G is comprised, for example of pure water. The removal liquid is preferably supplied to the glass plate G in the form of heated hot water. The temperature of the removal liquid is preferably, for example, 40 to 60°C, but is not limited to this range.

The removal liquid may also contain alkaline electrolyzed water. By using alkaline electrolyzed water as the removal liquid, each main surface Ga, Gb of the glass plate G is covered with negative ions, and the particulate matter removed from the glass plate G and dispersed in the removal liquid is present on each main surface of the glass plate G ( Ga, Gb) can be prevented from being reattached. Thereby, the cleanliness of each main surface Ga, Gb of glass plate G after 1st washing|cleaning process S21 can be raised.

The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned effects. Various changes are possible for this invention within the range which does not deviate from the summary of this invention.

Although the said embodiment illustrated the manufacturing method of glass plate G provided with liquid removal process S22 between 1st cleaning process S21 and 2nd cleaning process S23, this invention is not limited to this structure. . In this invention, you may omit the liquid removal process (S22), for example.

Although disk-shaped (disk-shaped) ones were exemplified as the cleaning tools 8a, 8b, 15a, and 15b in the above embodiment, the present invention is not limited to this configuration. The cleaning tool may be constituted by a cleaning roller or other cleaning device.

The present invention is a liquid removal process for removing the second cleaning liquid CS2 (alkaline cleaning liquid) adhering to the glass plate G by the second cleaning process S23 between the second cleaning process S23 and the rinse process S24. may be provided.

(Example)

Hereinafter, examples according to the present invention will be described, but the present invention is not limited to these examples. The present inventors conducted a test to confirm the quality of the glass plate manufactured by the present invention. The test was conducted by two methods, the first method and the second method, as described in detail below.

In the test according to the first method, a clean and dried rectangular test soda glass plate and a resin sheet were used. The size of the glass plate is 100 mm x 100 mm and 0.7 mm thick. The size of the resin sheet is 150 mm x 150 mm. After storing the resin sheet in contact with the glass plate for 3 months, the resin sheet was removed from the glass plate, and a test piece of the glass plate on which calcium contamination and organic matter-containing contamination were formed (Examples 1 to 5, Comparative Example 1) was prepared. did.

In the test, after washing the glass plates according to Examples 1 to 5 with an acidic washing liquid (first washing liquid), the glass plate was washed with an alkaline washing liquid (second washing liquid). In this case, the glass plates according to Examples 1 to 5 were washed with different concentrations of the acidic washing liquid and the alkaline washing liquid. Further, the glass plate according to Comparative Example 1 was washed with an alkaline cleaning liquid (first cleaning liquid), and then washed with an acidic cleaning liquid (second cleaning liquid).

Specifically, the washing liquid at a predetermined concentration was blown with a shower, a polyvinyl alcohol (PVA) sponge was impregnated with the washing liquid, and the glass plate was rubbed for 30 seconds, then manually rinsed with pure water and dried with dry air.

The present inventors evaluated the cleaning results for the glass plates according to Examples 1 to 5 and Comparative Example 1. The evaluation of the cleaning result was performed by visually checking the presence or absence of contamination on the surface of the glass plate using reflection and transmission of light to the surface of the glass plate using illumination with an illumination intensity of 1500 lux by a fluorescent lamp (visual inspection). . In addition, evaluation of the washing result was performed by visual inspection using reflection of light on the surface of the glass plate using illumination with an illumination intensity of 10000 lux by halogen illumination with a higher intensity. The evaluation results were performed in three stages: ○ (good), △ (normal), and × (unacceptable).

Evaluation of ○ (good) in Table 1 is a point-shaped or linear surface foreign matter under the conditions of 1500 lux of illumination by fluorescent lamp and 10000 lux of 10000 lux by halogen illumination in visual inspection, and translucent shape due to residual of detergent. It shows that a clean and transparent glass plate in which no stain of is observed is obtained.

In the evaluation of Δ (normal) in Table 1, no surface foreign matter was observed under the fluorescent light illumination intensity of 1500 lux, but micro foreign matter residues, bleed-out foreign substances, or detergent components were detected by visual inspection under the condition of illumination intensity of 10000 lux under halogen illumination. It indicates that translucent stains, which are considered to be thin film-like remnants, were observed.

On the other hand, in Table 1, the evaluation of × (not acceptable) is determined when the remaining foreign matter or translucent stain is observed in a visual inspection using illumination with an illumination intensity of 1500 lux by a fluorescent lamp.

Table 1 shows the test results. In addition, the concentration of the acidic washing liquid represents the concentration (mass %) of glycolic acid, and the concentration of the alkaline washing liquid represents the total concentration (mass %) of sodium hydroxide and potassium hydroxide. In the alkaline cleaning solution, the concentrations (% by mass) of sodium hydroxide and potassium hydroxide were the same.

As shown in Table 1, the cleaning results for Examples 1 to 5 were judged as good and normal. Among these, in Examples 3 and 4, no contamination was observed in the visual inspection with a fluorescent lamp, but in the visual inspection with strong illumination using a halogen lamp, micro foreign matter considered to be slightly insufficient, residual acidic detergent, or film-like foreign matter A white, opaque thin stain thought to be due to the remaining of was observed.

On the other hand, in Comparative Example 1, stains containing organic substances could not be sufficiently removed from the glass plate, and it was judged as poor cleaning.

Here, in many cases, calcium contamination adheres to the surface of the glass plate after contamination containing organic matter due to bleed-out adheres. For this reason, in many cases, a part or all of the surface of soil containing organic matter is covered with calcium soil. Therefore, when cleaning with an alkaline cleaning liquid (first cleaning liquid) and then cleaning with an acidic cleaning liquid (second cleaning liquid) as in Comparative Example, in cleaning with an alkaline cleaning liquid, the exposed portion of the surface in the dirt containing organic matter is removed, and the acidic cleaning liquid Rinsing by , tends to remove calcium contamination. As a result, it is presumed that the non-exposed portion of the surface in the contamination containing organic substances tends to remain, and the contamination containing organic substances cannot be sufficiently removed from the glass plate. From this test result, it was confirmed that the cleaning power was improved by cleaning the glass plate with an acidic cleaning solution and then washing the glass plate with an alkaline cleaning solution.

In the test by the second method, a rectangular glass plate cleaned and dried by a predetermined method and a polyethylene foamed resin sheet were used. The size of the glass plate is 370 mm x 470 mm and a thickness of 0.5 mm. This glass plate is an alkali-free borosilicate glass plate (material: Nippon Electric Glass Co., Ltd. product OA-11) for liquid crystal displays. The size of the resin sheet is 400 mm x 500 mm and a thickness of 0.085 mm.

A polyethylene foam resin sheet was superposed on a glass plate to form a glass laminate. As for the glass laminate, a combination of one glass plate and one resin sheet was used as one set, and a plurality of sets of glass laminates were laminated in a horizontal position. These multiple sets of glass laminates are reproduced assuming the storage state loaded on the pallet for transportation.

This glass laminate was placed in a constant temperature and humidity tester, and an accelerated environmental test was conducted by changing the temperature and humidity in the tester. Details of the accelerated environment test will be described below.

In this test, the 1st process and the 2nd process with different temperature and humidity were repeatedly implemented. Specifically, the combination of the first step and the second step was made into one cycle, and this cycle was repeated 180 times.

In the first step, the inside of the test machine was set to high temperature and high humidity. The set temperature in the testing machine in the first step is 50°C, and the set humidity is 70%. In the second process, the inside of the test machine was set to normal temperature and normal humidity. The set temperature in the testing machine in the second step is 25°C, and the set humidity is 50%.

The cycle of the 1st process and the 2nd process was set as follows. First, the temperature and humidity of the first step are maintained for 1 hour. After that, the temperature and humidity in the tester are lowered over 1 hour until the condition of the second step is reached. And the temperature and humidity of the 2nd process are maintained for 1 hour. After that, the temperature and humidity in the tester are raised over 1 hour until the condition of the first step is reached. Maintaining, lowering, and raising the temperature and humidity constitute one cycle. This one cycle reproduces the change in temperature and humidity of the surrounding environment in a short time when the glass laminate is stored for one day. In this test, a state in which the glass laminate was stored for 180 days was virtually reproduced by repeating 180 cycles.

The components of the resin sheet were transferred and stained on a glass plate by the above accelerated environmental test. After that, the resin sheet was removed from the glass plate, and test pieces (Examples 6 to 10, Comparative Example 2) of the glass plate on which calcium stains and stains containing organic substances were formed were produced.

The cleaning of the glass plate in this second method was performed by the cleaning device 1 according to the first embodiment. In the cleaning of the glass plate by the cleaning device 1, washing condition 1 using pure water not containing alkaline electrolyzed water as a rinse liquid and washing condition 2 using pure water containing alkaline electrolyzed water were set in the rinse step.

The evaluation of the cleaning result was performed by visual inspection of the surface of the glass plate using light with an illumination intensity of 1500 lux by a fluorescent lamp and visual inspection of the surface of the glass plate using light with an illumination intensity of 10000 lux by a halogen light in the same manner as in the first method described above. . For each of Examples 6 to 10 and Comparative Example 2, five glass plates were inspected, and evaluated in three stages: ○ (good), △ (normal), and × (unacceptable).

In addition, in the test by the second method, the number of fine foreign matters (particles) of 1 μm or more on the surface of the glass plate after washing was measured using a particle measuring instrument GI7200 manufactured by Hitachi High-Tech Corporation. About Examples 6-10 and Comparative Example 2, each glass plate of 1 sheet was measured, and the result was compared. In addition, the number of particles was expressed by converting the number detected within 370 mm × 470 mm into the number per 1 m 2 (1000 mm × 1000 mm).

Table 2 shows the test results. In addition, the concentration of the acidic washing liquid represents the concentration (mass %) of glycolic acid, and the concentration of the alkaline washing liquid represents the total concentration (mass %) of sodium hydroxide and potassium hydroxide. In the alkaline cleaning liquid, the concentrations (% by mass) of sodium hydroxide and potassium hydroxide were the same. The fluorescent lamp test and halogen test results in Table 2 show that the glass plate was washed under the washing condition 1, since there was no significant difference between the glass plate after washing under the washing condition 1 and the glass plate after washing under the washing condition 2.

As shown in Table 2, the cleaning results for Examples 6 to 10 were judged as good and normal. Among them, in Examples 7 and 8, the number of particles was as low as 100 to 200 pieces/m 2 , and was good, as well as the results of the fluorescent lamp test and the halogen test.

In Examples 6 and 10, no contamination was observed in the visual inspection with a fluorescent lamp, but in the visual inspection with a halogen lamp, white extremely thin stains, which are thought to be caused by the residual detergent component, were observed, and the number of particles was also 500 to 1000. /m² showed a relatively high number.

In Example 9, no contamination was observed in the visual inspection with a fluorescent lamp, but in the visual inspection with a halogen lamp, microscopic foreign matter thought to be insufficient cleaning was observed, and the number of particles increased to 700 particles/m 2 . In addition, in the rinsing step, in the washing condition 2 using pure water containing alkaline electrolyzed water, compared to the washing condition 1 using pure water not containing alkaline electrolyzed water, in any of Examples 6 to 10, the number of particles is reduced, , it was confirmed that there is an effect of preventing reattachment of foreign matter.

On the other hand, about Comparative Example 2, stains containing organic substances could not be sufficiently removed from the glass plate, and it was judged as poor cleaning. The number of particles was also as high as 10,000 particles/m2, and in visual inspection, bleeding traces (stripe-like stains) due to irregularly remaining foreign matter due to irregularities on the surface of the foamed resin sheet were observed on the glass plate, Comparative Example 2 has become defective.

8a: upper cleaning port 8b: lower cleaning port
15a: upper cleaning port 15b: lower cleaning port
CS1: first cleaning solution CS2: second cleaning solution
G: glass plate RS: resin sheet
S1: storage process S2: cleaning process
S21: First cleaning process S22: Liquid removal process
S23: Second cleaning process S24: Rinsing process

Claims (9)

A manufacturing method of a glass plate comprising a storage step of storing a glass plate in contact with a resin sheet and a washing step of washing the glass plate after the storage step,
The cleaning step includes a first cleaning step of cleaning the glass plate by supplying a first cleaning solution to the glass plate, and a second cleaning step of cleaning the glass plate by supplying a second cleaning solution to the glass plate after the first cleaning step. do,
The method of manufacturing a glass plate, characterized in that the first cleaning liquid is an acidic cleaning liquid, and the second cleaning liquid is an alkaline cleaning liquid. According to claim 1,
The method of manufacturing a glass plate in which the acidic cleaning liquid contains a hydroxy acid. According to claim 2,
The method of manufacturing a glass plate in which the hydroxy acid includes glycolic acid. According to any one of claims 1 to 3,
The alkaline cleaning solution is a method for producing a glass plate containing a hydroxide salt. According to any one of claims 1 to 4,
The manufacturing method of the glass plate in which the said alkaline cleaning liquid contains at least one of sodium hydroxide and potassium hydroxide. According to any one of claims 1 to 5,
The manufacturing method of the glass plate which cleans the said glass plate by making a cleaning tool contact the said glass plate in the said 1st cleaning process. According to any one of claims 1 to 6,
The manufacturing method of the glass plate which cleans the said glass plate by making a cleaning tool contact the said glass plate in the said 2nd cleaning process. According to any one of claims 1 to 7,
After the first cleaning step and before the second cleaning step, a liquid removing step of removing the first cleaning liquid adhering to the glass plate by supplying a removing liquid to the glass plate;
The method of manufacturing a glass plate in which the removal liquid is hot water. According to any one of claims 1 to 8,
a rinsing step of removing the second cleaning fluid adhering to the glass plate by supplying a rinsing fluid to the glass plate after the second cleaning step;
The method of manufacturing a glass plate in which the rinsing liquid includes alkaline electrolyzed water.

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