JP2005048140A - Coating agent for glass base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating agent for glass base material that can increase the flexibility of the glass base material to be subjected to display. <P>SOLUTION: This invention is a coating agent for glass base material, the coating agent includes polyether sulfone and the solvent of the coating agent is selected from aromatic hydrocarbon, halogenated hydrocarbon, ester, ketone, nitrile and sulfoxide. Preferably, the coating agent includes a silica precursor. Further, in a preferred embodiment, the solvents are selected from two or more kinds of chemicals composed of aromatic hydrocarbon, halogenated hydrocarbon, ester, ketone, nitrile and sulfoxide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coating agent for improving the flexibility of a thin glass substrate used for thin displays such as organic EL displays and liquid crystal displays.

  Thin displays such as organic EL displays and liquid crystal displays are expected to be applied to portable devices, electronic paper, cards, electronic books, etc., and the displays are required to be thin and light and flexible. Therefore, further reduction in thickness and flexibility are required for glass substrates used in them. When the thickness of the glass substrate is set to 500 μm or less, a certain degree of flexibility can be obtained. However, since the level is not sufficient, development has been made to improve the flexibility by providing a polymer layer on the glass substrate. ing.

Patent Document 1 discloses a glass substrate for liquid crystal display in which a thin plate made of glass is provided on at least one surface of a transparent resin substrate. In Patent Document 2, a flexible glass substrate made of glass and plastic having a thickness of ≦ 200 μm, and in Patent Document 3, a glass substrate having a thickness of 10 μm to 500 μm is applied to a silicone polymer having a thickness of 1 μm to 200 μm. A glass substrate in which a resin layer such as polyethersulfone is directly applied without using an adhesive by UV treatment or the like is disclosed.
JP-A-4-235527 JP 11-329715 A Special Table 2002-534305 gazette

  When manufacturing a display, there is a temperature raising / lowering process, and a thermal load is applied to the substrate. Particularly in a high-definition display equipped with a thin film transistor (TFT), stability at a temperature of 350 ° C. or higher is required. Therefore, the polymer layer provided on the glass substrate is preferably excellent in heat resistance. Patent Document 3 discloses a glass substrate coated with polyethersulfone having excellent heat resistance. However, since it is a coating by an extrusion method, it is difficult to control the film thickness, and a homogeneous film-coated glass is obtained. Is difficult.

  The present invention provides a means for effectively coating polyether sulfone with excellent heat resistance on a glass substrate, and further a means for improving the adhesion between the coating film made of polyether sulfone and the glass substrate. This is the issue.

  In view of the above-described problems, the present invention has developed a coating agent that can effectively coat a polyether substrate with polyethersulfone that has excellent heat resistance but low solubility in a solvent. That is, the coating agent of the present invention is a coating agent for improving the flexibility of a glass substrate to be used for display, the coating agent having polyethersulfone, and the solvent of the coating agent is aromatic. It is one of group hydrocarbons, halogenated hydrocarbons, esters, ketones, nitriles, and sulfoxides. The solvent is selected from chemical species belonging to any of aromatic hydrocarbons, halogenated hydrocarbons, esters, ketones, nitriles and sulfoxides in order to make polyethersulfone stable in the coating agent. Two or more types are preferably selected.

  Moreover, in order to improve the adhesiveness to the glass base material of the film | membrane obtained from a coating agent, it is preferable to make a coating material contain a silica precursor. As this content, the silica precursor is added to the coating agent so that the silica formed from the silica precursor is 0.5 wt% to 20 wt% based on the total amount of polyethersulfone and silica. It is preferable to contain. If it is less than 0.5% by weight, the effect of adhesion to the glass substrate by silica hardly appears, and if it exceeds 20% by weight, it is difficult to obtain a homogeneous coating agent.

  Film-coated glass obtained by applying the coating agent to a glass substrate has improved flexibility as compared with a glass substrate not coated with a film. As the glass substrate, a glass substrate having a thickness of 500 μm or less can be suitably used.

  The film-coated glass substrate obtained from the coating agent of the present invention is excellent in flexibility. In addition, even when the display is manufactured at 350 ° C. or higher, optical characteristics such as visible light transmittance are maintained, so that it is excellent as a glass substrate for organic EL displays or liquid crystal displays equipped with TFTs.

  The coating agent for improving the flexibility of the glass substrate used for the display of the present invention has polyether sulfone, and the solvent of the coating agent is an aromatic hydrocarbon, a halogenated hydrocarbon, an ester. , Ketones, nitriles, or sulfoxides. The polyethersulfone is preferably used in the form of powder because it is easily dissolved in a solvent. The size of the powder particles is not particularly limited, and it can be used in the range of 10 μm to 2 mm, more preferably in the range of 100 μm to 500 μm.

  Solvents include aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as methyl chloride, methylene chloride, chloroform and trichloroethylene; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; Aprotic polar solvents (nitriles such as N-methylpyrrolidone and acetonitrile, amides such as dimethylformamide and dimethylacetamide, sulfoxides such as dimethylsulfoxide, and the like) can be used.

  The content of polyethersulfone with respect to the solvent is preferably in the range of 1 wt% to 20 wt% in view of the film thickness after film formation.

  In order to stabilize the coating agent containing polyethersulfone, it is preferable to use a mixed solvent in which two or more of the above-mentioned chemical species are used. Two-component mixed systems such as “N-methylpyrrolidone-toluene”, “N-methylpyrrolidone-xylene”, “N-methylpyrrolidone-dichloromethane”, “1,1,2-trichloroethane-dichloromethane”, “dimethylformamide- Application of a mixed solvent such as a three-component mixed system such as “cyclohexanone-methyl ethyl ketone” is particularly preferable.

  In order to improve the uniformity of the film surface obtained from the coating material, it is also possible to add a surfactant as a surface conditioner to the solvent. The surfactant includes silicone, fluorine, carboxylate, sulfate ester, sulfonate, amine hydrochloride, bromine, chlorine, betaine, imidazoline, amine oxide, ether, Any of the ester systems can be used.

  Silica precursors that may be included in the coating agent include trimethoxysilane, triethoxysilane, tripropoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyl Trimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-mercaptopropyltrimethoxy Silane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, phenyltrimethoxysilane, phenyl Silane, phenyl tripropoxy silane, diphenyl dimethoxy silane, available diphenyl diethoxy silane, economy, the use of tetraethoxysilane and methyltriethoxysilane view of speed of hydrolysis is preferred.

  Application of the coating agent of the present invention to a glass substrate can be performed by known means such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, flexographic printing and the like. After the coating agent is applied to the glass substrate, a film made of polyethersulfone or a film made of a composition of “polyethersulfone-silica” is passed through a drying step and a baking step at 250 ° C. to 400 ° C. A coated film-coated glass can be obtained.

  The thickness of the coating film is preferably 0.5 μm to 10 μm, more preferably 1 μm to 5 μm. If the film thickness of the coating film is less than 0.5 μm, the effect of improving the flexibility of the glass substrate is small, and if the film thickness of the coating film exceeds 10 μm, the effect of improving the flexibility is small. . The film may be formed on one side or both sides of the substrate. Further, it is more preferable that the coating is formed on the end surface of the glass substrate, which increases the impact resistance of the end surface, avoids the expansion of minute cracks that may exist on the glass end surface, and increases the strength of the glass substrate.

  In addition, the glass substrate of the film-coated glass includes soda-lime glass, borosilicate glass, aluminosilicate glass, aluminoborosilicate glass, preferably organic EL displays such as low alkali glass and non-alkali glass, and thin films such as liquid crystal displays. Glass substrates used for display applications can be used. In order to promote the adhesion of the polymer layer to the glass substrate, any of water washing, ultrasonic washing, alkali washing, glass detergent washing, UV irradiation in an ozone-containing atmosphere, corona treatment, primer treatment, Or 2 or more types can also be given. Since these thin glass substrates for display are preferably flexible, a glass substrate having a thickness of 500 μm or less can be used. The glass substrate having a thickness of 10 μm to 400 μm, preferably 10 μm to 100 μm, more preferably 10 μm to 50 μm, which is required as a thin display substrate, can be used. It is difficult to produce a glass substrate thinner than 10 μm. On the other hand, a glass substrate having a thickness of more than 500 μm has low flexibility, and even if the coating agent of the present invention is applied, the effect of improving flexibility cannot be obtained. Because.

  The film-coated glass obtained from the coating agent of the present invention can be used for solar cells such as dye-sensitized solar cells, sensors, etc., in addition to thin displays such as organic EL displays and liquid crystal displays.

Hereinafter, the present invention will be described in more detail with reference to examples. Samples obtained in each example were evaluated by the test methods listed below.
(1) Evaluation of optical characteristics after holding at high temperature After holding a sample at 400 ° C. for 15 minutes, 30 minutes, 45 minutes, and 60 minutes, the visible light transmittance and haze index of the sample for each holding time The haze value was measured. Visible light transmittance was measured with a spectrophotometer [U-4000; Hitachi, Ltd.] at a light wavelength of 380 nm to 780 nm, and JIS R 3106 “Acquired transmittance, reflectance, emissivity, and solar heat of plate glass” The visible light transmittance was determined in accordance with the “rate test method”. The haze value was measured with a haze meter [NDH-20D; Nippon Denshoku Industries Co., Ltd.] and determined according to JIS K 7105 “Testing method for optical properties of plastics”.
(2) Evaluation of flexibility The sample is wound around an acrylic cylinder having a different diameter, and the curvature radius of the smallest cylinder among the cylinders in which the sample is not broken by the winding is defined as the limit curvature. It was used as an index of sex.
(3) Adhesion evaluation of film to glass substrate The adhesion of the film to the glass substrate was evaluated by a cross peel test. The cross peel test is a test in which 10 cuts in the form of a cross cut are made in the coating film to check the presence or absence of peeling when peeled with an adhesive tape (eg, a mending tape). 0/100 is 100 This indicates that the number of frames peeled in the frame is zero.

Example 1
271 parts by weight of N-methylpyrrolidone, 271 parts by weight, 124 parts by weight of xylene, 100 parts by weight of polyethersulfone (SEP5003P manufactured by Sumitomo Chemical Co., Ltd.), and 1 part by weight of a surface conditioner (BYK-by BYK Chemie) 300) was stirred and mixed for 2 hours to obtain a coating agent.

  The coating agent was applied to two types of glass substrates of 400 μm thick soda-lime glass (100 mm × 100 mm) and 100 μm thick borosilicate glass (50 mm × 50 mm) by spin coating. Thereafter, the film was baked at 100 ° C. for 30 minutes and at 350 ° C. for 30 minutes to obtain a film-coated glass on which a film having a thickness of 4 μm made of polyethersulfone was formed.

  The film-coated glass made of soda-lime glass was used to evaluate the optical characteristics and the adhesiveness, and the film-coated glass made of borosilicate glass was used to evaluate the flexibility.

  Table 1 shows the results of the visible light transmittance and Table 2 shows the results of the haze values regarding the evaluation results of the optical properties after being held at high temperature. Film-coated glass made of polyethersulfone shows visible light transmittance and haze value similar to a single glass substrate, and there is almost no change in visible light transmittance and haze value even in a standing test in a 400 ° C environment. It was a film-coated glass with excellent heat resistance. In addition, as shown in Table 3, the flexibility was excellent in flexibility because it could be wound around a cylinder with a small radius of curvature compared to a glass base material on which no film was formed.

実施例２
Ｎ−メチルピロリドン２７１重量部、及びキシレン１２４重量部の混合溶媒に粉末状のポリエーテルサルホン１００重量部を混合し２時間撹拌した。これにシリカ前駆体としてテトラエトキシシラン３９重量部、及び表面調整剤（ＢＹＫ−３００）を１重量部添加後、３時間撹拌混合することでコーティング剤を得た以外は、実施例１と同様の操作を行い、ポリエーテルサルホン及びシリカからなる膜厚４μｍの膜が形成された膜被覆ガラスを得た。

Example 2
In a mixed solvent of 271 parts by weight of N-methylpyrrolidone and 124 parts by weight of xylene, 100 parts by weight of powdered polyethersulfone was mixed and stirred for 2 hours. The same as in Example 1 except that 39 parts by weight of tetraethoxysilane and 1 part by weight of a surface conditioner (BYK-300) were added as a silica precursor, and the coating agent was obtained by stirring and mixing for 3 hours. Operation was performed to obtain a film-coated glass on which a film of 4 μm thick composed of polyethersulfone and silica was formed.

  The film-coated glass exhibits a visible light transmittance and haze value close to a single glass substrate, and even in a standing test under a 400 ° C. environment, the visible light transmittance and haze value are hardly changed, and the heat resistance is low. It was an excellent film-coated glass. In addition, regarding flexibility, it was possible to wind up to a cylinder with a small radius of curvature as compared with a glass substrate on which no film was formed, and the flexibility was excellent. Furthermore, as shown in Table 4, the film-coated glass was superior in film adhesion to the glass substrate as compared with the film-coated glass of Example 1.

実施例３
Ｎ−メチルピロリドン２７１重量部とキシレン１２４重量部の混合溶媒に粉末状のポリエーテルサルホン１００重量部を混合し２時間撹拌した。これにシリカ前駆体としてテトラエトキシシラン７重量部、及び表面調整剤（ＢＹＫ−３００）を１重量部添加し、３時間撹拌混合しコーティング剤を得た以外は、実施例１と同様の操作を行い、ポリエーテルサルホン及びシリカからなる膜厚４μｍの膜が形成された膜被覆ガラスを得た。

Example 3
100 parts by weight of powdered polyethersulfone was mixed in a mixed solvent of 271 parts by weight of N-methylpyrrolidone and 124 parts by weight of xylene and stirred for 2 hours. To this, 7 parts by weight of tetraethoxysilane and 1 part by weight of a surface conditioner (BYK-300) were added as a silica precursor, and the mixture was stirred and mixed for 3 hours to obtain a coating agent. Then, a film-coated glass on which a film having a film thickness of 4 μm made of polyethersulfone and silica was formed was obtained.

  The film-coated glass exhibits a visible light transmittance and haze value close to a single glass substrate, and even in a standing test under a 400 ° C. environment, the visible light transmittance and haze value are hardly changed, and the heat resistance is low. It was an excellent film-coated glass. In addition, regarding flexibility, it was possible to wind up to a cylinder with a small radius of curvature as compared with a glass substrate on which no film was formed, and the flexibility was excellent. Furthermore, as shown in Table 4, the film-coated glass was superior in film adhesion to the glass substrate as compared with the film-coated glass of Example 1.

Comparative Example 1
For comparison, the glass substrate used in Example 1 was not coated with a film. Compared with the film-coated glass of Examples 1 to 3, the flexibility was inferior.

Comparative Example 2
100 parts by weight of powdered polyethersulfone was mixed in a mixed solvent of 271 parts by weight of N-methylpyrrolidone and 124 parts by weight of xylene and stirred for 2 hours. When 115 parts by weight of tetraethoxysilane and 1 part by weight of a surface conditioner (BYK-300) were added as a silica precursor, a white precipitate was precipitated.

Claims (5)

A coating agent for improving the flexibility of a glass substrate used for display, wherein the coating agent has polyethersulfone, and the solvent of the coating agent is an aromatic hydrocarbon or a halogenated hydrocarbon A coating agent characterized by being one of esters, ketones, nitriles, and sulfoxides. 2. The coating according to claim 1, wherein the solvent is selected from two or more chemical species belonging to any of aromatic hydrocarbons, halogenated hydrocarbons, esters, ketones, nitriles, and sulfoxides. Agent. The coating agent according to claim 1 or 2, wherein the coating agent has a silica precursor. The coating agent has a silica precursor so that the silica formed from the silica precursor is 0.5 wt% to 20 wt% based on the total amount of polyethersulfone and silica. The coating agent according to claim 3. A film-coated glass obtained by applying the coating agent according to any one of claims 1 to 4.