JP4882854B2 - Glass coating composition - Google Patents

Description

  The present invention relates to a coating composition using an organic-inorganic hybrid material starting from a raw material used in a sol-gel method, and a method for producing the same.

  Liquid crystal displays are classified into a simple matrix type represented by a twisted nematic (TN) panel and a super twisted nematic (STN) panel and an active matrix type represented by a thin film transistor (TFT). For film-forming substances and liquid crystal materials formed on glass substrates, elution of alkali components (especially Na) in glass causes deterioration of device characteristics, resulting in degradation of image quality and reduction of contrast. Initially, the type used alkali-free glass as the glass substrate.

Later, a technology to protect the elution of alkali components from glass with a SiO ₂ film was established, and soda lime glass coated with SiO ₂ or the like was used for the simple matrix type that required low cost. ing. Currently, coating by a liquid phase film forming process such as a dip coating method is generally performed (see, for example, Patent Documents 1 to 3).

  In the active matrix type, elution of a trace amount of alkali components from the glass adversely affects the TFT performance. A porous silica film does not provide sufficient alkali elution prevention performance. In addition, heating of the silica film requires heating at 500 ° C. or higher, and warping is likely to occur in a glass substrate having a thickness of about 0.7 mm. Furthermore, there is a problem that the silica film tends to become cloudy. For this reason, soda lime glass coated with a silica film has not been adopted for TFT substrates.

Alkali-free glass having excellent chemical resistance and heat resistance is used in order to fundamentally eliminate alkali elution and to reduce surface degradation against acids and alkalis used in patterning. The alkali-free glass is a glass that does not contain an alkali oxide represented by the general formula R′O—Al ₂ O ₃ —SiO ₂ (R ′ is a divalent element). However, when producing glass industrially, it is difficult to keep the alkali metal content to zero, so those with an alkali content of less than 0.5% by weight are conventionally called alkali-free glass. It is.

Alkali-free glass has excellent heat resistance, chemical durability, high electrical insulation, high elastic modulus, and low coefficient of thermal expansion. In addition to glass substrates for liquid crystal displays, organic EL display substrates and solar cells. It is used for textiles such as cloth materials for substrates and printed wiring boards.
JP-A-6-293535 Japanese Patent Application Laid-Open No. 6-263481 Japanese Patent Laid-Open No. 10-253972

  The alkali-free glass has a high processing temperature of 650 ° C. or higher, and requires a lot of energy for processing. In addition, if the base is changed frequently for the production of alkali-free glass in a factory that normally manufactures soda-lime glass, it takes a long time (several days) to work, resulting in high costs. was there.

  The present invention is characterized in that an organic-inorganic hybrid coating material is coated on soda lime glass that is inexpensive and easy to increase in area, and is heat-cured at a temperature at which the glass does not warp to provide alkali elution prevention performance. .

The present invention relates to an organic-inorganic hybrid material (precursor) containing at least one organic substituent selected from the group consisting of aromatic or aromatic hydrocarbon groups, saturated hydrocarbon groups and unsaturated hydrocarbon groups and a siloxane bond. ) is dissolved in an organic solvent, applied to the surface of the glass, cured, coated surface of the glass, an organic-inorganic hybrid coating materials to prevent the elution of alkaline components from the glass into the water, the raw material of the alkoxysilane Among them, alkoxysilanes containing aromatic or aromatic hydrocarbon groups are 10% to 60% in molar ratio, and alkoxysilanes containing saturated hydrocarbon groups are 20% to 80% in molar ratio, The alkoxysilane containing a saturated hydrocarbon group is 50% or less in molar ratio, and the tetrafunctional alkoxysilane is 50% or less in molar ratio. That is an organic-inorganic hybrid coating material.

Moreover, it is said organic-inorganic hybrid coating material characterized by containing a tetrafunctional group in a siloxane network.

Also, 10-50 times water, 10 times alcohol or less, 0.001-1 times acid catalyst are added to alkoxysilane in a molar ratio, and the mixed solution is heated at 50-110 ° C. for 1 hour-1 week. The organic-inorganic hybrid coating material is characterized in that a precursor is synthesized.

Moreover, it is said organic-inorganic hybrid coating material characterized by stabilizing a precursor by heating under reduced pressure at 20-110 degreeC for 5 minutes-10 hours.

Further, the organic-inorganic hybrid coating material is characterized in that the precursor is dissolved in an organic solvent to form a solution having a solid concentration of 3 to 30% by weight and applied to the glass surface.

Furthermore, it is said organic-inorganic hybrid coating material characterized by hardening | curing by heating at 100-500 degreeC after apply | coating to the glass surface.

  According to the present invention, an organic / inorganic hybrid coating material can be coated on soda lime glass that is inexpensive and easy to increase in area, and can be imparted with alkali elution prevention performance by heat curing at a temperature at which the glass does not warp.

The present invention relates to an organic-inorganic hybrid material (precursor) containing at least one organic substituent selected from the group consisting of aromatic or aromatic hydrocarbon groups, saturated hydrocarbon groups and unsaturated hydrocarbon groups and a siloxane bond. ) is dissolved in an organic solvent, applied to the surface of the glass, cured, coated surface of the glass, an organic-inorganic hybrid coating materials to prevent the elution of alkaline components from the glass into the water, the raw material of the alkoxysilane Among them, alkoxysilanes containing aromatic or aromatic hydrocarbon groups are 10% to 60% in molar ratio, and alkoxysilanes containing saturated hydrocarbon groups are 20% to 80% in molar ratio, The alkoxysilane containing a saturated hydrocarbon group is 50% or less in molar ratio, and the tetrafunctional alkoxysilane is 50% or less in molar ratio. That is an organic-inorganic hybrid coating material.

  It is preferable to dissolve an organic-inorganic hybrid substance (precursor) containing an organic substituent and a siloxane bond in an organic solvent, and apply and cure. This is because when the precursor is not dissolved in the organic solvent, the viscosity, film thickness, and film uniformity of the substance before coating cannot be controlled. Although it does not specifically limit as an organic solvent in this invention, Alcohol, ester, etc. are preferable, and especially ethanol, isopropyl alcohol, isobutyl acetate, etc. are preferable.

  It is preferable to contain an aromatic or aromatic hydrocarbon group as the organic substituent. Examples of the aromatic or aromatic hydrocarbon group include a phenyl group, a naphthyl group, a benzyl group, a phenethyl group, and a naphthylmethyl group, and a phenyl group is particularly preferable.

  It is preferable to contain a saturated hydrocarbon group as an organic substituent. Examples of the saturated hydrocarbon group include a methyl group, an ethyl group, an (n-, i-) propyl group, and an (n-, i-, s-, t-) butyl group, and a methyl group is particularly preferable.

  It is preferable to contain an unsaturated hydrocarbon group as an organic substituent. Examples of the unsaturated hydrocarbon group include a vinyl group, an allyl group, and a (1-, i-) propenyl group, and a vinyl group is particularly preferable.

  It is preferable to contain a tetrafunctional group in the siloxane network. By introducing tetrafunctional groups, the film becomes dense and the film strength is improved. Examples of the raw material for the tetrafunctional group include tetramethoxysilane, tetraethoxysilane, and tetra-n-propoxysilane. Tetraethoxysilane is particularly preferable.

  Among the alkoxysilanes used as the base material, an alkoxysilane containing an aromatic or aromatic-containing hydrocarbon group is 10% to 60% in molar ratio, and an alkoxysilane containing a saturated hydrocarbon group is 20% or more in molar ratio. It is preferable that 80% or less, alkoxysilane containing an unsaturated hydrocarbon group is 50% or less in terms of molar ratio, and tetrafunctional alkoxysilane is 50% or less in terms of molar ratio.

  The reason for determining each composition is as follows. If the alkoxysilane containing an aromatic or aromatic hydrocarbon group is 10% or less in molar ratio, gelation or rubberization is likely to occur and coating is not preferable. When the molar ratio of alkoxysilane containing an aromatic or aromatic hydrocarbon group is 60% or more, it is not preferable because it has a heat softening property and it is difficult to maintain its shape during heating. When the alkoxysilane containing a saturated hydrocarbon group is 20% or less by molar ratio, it is not preferable because cracks are likely to occur due to temperature changes after curing. When the alkoxysilane containing a saturated hydrocarbon group is 80% or more by molar ratio, gelation is likely to occur and coating is impossible, which is not preferable. When the alkoxysilane containing an unsaturated hydrocarbon group is 50% or more in a molar ratio, it becomes easy to rubberize and becomes a foam after curing, and the crosslinking between unsaturated hydrocarbon groups is irregular by heat or ultraviolet light. Occurs and the physical properties are not stable. A tetrafunctional alkoxysilane in a molar ratio of 50% or more is not preferable because cracks are likely to occur after heat treatment.

  Moreover, it is preferable to add 10 to 50 times water, 10 times or less alcohol, and 0.001 to 1 times acid catalyst in molar ratio with respect to alkoxysilane. The reason for determining each addition amount is as follows. When the amount of water added is 10 times or less, the hydrolysis reaction does not proceed sufficiently and unreacted alkoxy groups remain, which is not preferable. When the amount of water added is 50 times or more, the viscosity of the precursor rapidly increases with the rapid progress of the hydrolysis / polycondensation reaction, which is not preferable. When the amount of alcohol added is 10 times or more, the synthesis time is long, and industrial advantages such as productivity are small, which is not preferable.

  Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 1.1-dimethyl-1-ethanol, etc. Ethanol is preferred. When the addition amount of the acid catalyst is 0.001 times or less, the hydrolysis reaction does not proceed sufficiently and unreacted alkoxy groups remain, which is not preferable. When the addition amount of the acid catalyst is 1 or more, it is not preferable because the viscosity of the main agent increases rapidly and is difficult to control. In the synthesis of the organic-inorganic hybrid material by the sol-gel method, a basic catalyst may be used, but it is desirable to use an acid catalyst. As the acid catalyst, organic acids such as acetic acid, formic acid, maleic acid, fumaric acid, propionic acid, adipic acid, oleic acid, stearic acid, linoleic acid, and benzoic acid are preferable, and acetic acid is particularly preferable.

  Further, the synthesis temperature of the precursor is preferably 50 to 110 ° C. and the synthesis time is preferably 1 hour to 1 week. The reason for determining each synthesis condition is as follows. When the synthesis temperature of the precursor is 50 ° C. or less, the synthesis time is long, and industrial advantages such as productivity are small, which is not preferable. A precursor synthesis temperature of 110 ° C. or higher is not preferable because a precursor having a desired composition cannot be obtained due to boiling of the mixed solution or evaporation of the raw material alkoxysilane. When the synthesis time of the precursor is 1 hour or less, the hydrolysis / polycondensation reaction does not proceed sufficiently, which is not preferable. When the precursor synthesis time is one week or longer, the synthesis time is long, and industrial advantages such as productivity are small, which is not preferable. The synthesis of the precursor may be performed in an open system or under reflux.

  In order to prevent problems such as yellowing due to residual acid catalyst, the catalyst residue can be removed by dissolving the precursor in an organic solvent immiscible with water, adding pure water, and extracting and separating the solution. It is valid. The separated organic layer is dehydrated and dried to obtain a stabilized precursor.

  Further, it is preferable to stabilize the precursor by heating under reduced pressure at 20 to 110 ° C. for 5 minutes to 10 hours. Heating under reduced pressure at 20 ° C. or less is not preferable because condensation of unreacted silanol groups and water remaining in the system and evaporation of the acid catalyst are insufficient, and a stabilizing effect cannot be obtained. Heating under reduced pressure at 110 ° C. or higher is not preferable because the viscosity of the precursor increases rapidly due to the rapid progress of the condensation reaction and cannot be controlled. Heating under reduced pressure for less than 5 minutes is not preferable because condensation of unreacted silanol groups and evaporation of water and acid catalyst remaining in the system are insufficient, and a stabilizing effect cannot be obtained. In the case of heating under reduced pressure for 10 hours or more, the viscosity of the precursor increases excessively and is difficult to control, which is not preferable.

  Moreover, it is preferable to dissolve the precursor in an organic solvent to obtain a solution having a solid content concentration of 3 to 30% by weight and apply the solution to the glass surface. When the solid content concentration is 3% or less, the film thickness becomes too thin, and a predetermined film thickness cannot be obtained, which is not preferable. A solid content concentration of 30% or more is not preferable because unevenness and cracks are likely to occur on the film surface. Although it does not specifically limit as an organic solvent in this invention, Alcohol, ester, etc. are preferable, and especially ethanol, isopropyl alcohol, isobutyl acetate, etc. are preferable. Application methods include dip coating, flow coating, spin coating, bar coating, roll coating, spray coating, screen printing, flexographic printing, and the like, but are not limited thereto.

  Moreover, after apply | coating to the glass surface, it is preferable to harden | cure by heating at 100-500 degreeC. When the heating temperature is 100 ° C. or lower, film curing does not proceed sufficiently, which is not preferable. When the heating temperature is 500 ° C. or higher, the aromatic or aromatic hydrocarbon group, saturated hydrocarbon group, or unsaturated hydrocarbon group causes thermal decomposition, which is not preferable. In addition, preheating may be performed in advance before firing, or preheating and firing may be performed under reduced pressure.

It is preferable that the elution amount of the sodium component from the glass coated on the surface is 0.01 μg / cm ² or less in terms of Na ₂ O. In the case of 0.01 μg / cm ² or more, device characteristic deterioration occurs, and for example, in a liquid crystal display device, image quality deterioration and contrast decrease occur.

  The surface-coated 2 mm soda lime glass is preferably 90% or more in the entire region of a wavelength of 380 to 800 nm. In the case of 90% or less, for example, a liquid crystal display element is not preferable because the light of the backlight is lost and sufficient luminance, image quality, and contrast cannot be maintained.

  Even after heating at 300 to 400 ° C. for 24 hours, it is preferable that the transmittance of the 2 mm thick soda lime glass whose surface is coated is 90% or more in all regions of wavelengths of 380 to 800 nm. Since the manufacturing process temperature of the amorphous silicon TFT is 300 to 400 ° C., it is desirable that deterioration does not occur particularly in this temperature range. In the case of 90% or less, for example, a liquid crystal display element is not preferable because the light of the backlight is lost and sufficient luminance, image quality, and contrast cannot be maintained.

  Even after heating at 300 to 400 ° C. for 24 hours, the transmittance of the 2 mm-thick soda lime glass coated on the surface is preferably 50% or more in all regions having a wavelength of 300 to 380 nm. When it is 50% or less, the UV transmittance is low, and therefore, for example, when a TFT substrate of a liquid crystal display and a color filter are bonded with a UV curable resin, there is a problem that the curing time becomes long. In particular, after forming a transparent conductive film, an insulating film, a semiconductor film, a metal film, etc. on a glass substrate, a TFT element is formed by photolithography based on a back exposure method in which ultraviolet light having a wavelength of about 300 nm is irradiated from the back surface of the glass substrate. In this case, it is preferable that the transmittance of the glass substrate in the ultraviolet region is also high.

  In addition, when used as a substrate for organic electroluminescence (organic EL) display that has been attracting attention in recent years, glass in a wavelength region corresponding to blue light with low luminous efficiency among red, green and blue organic phosphors. Higher transmittance is better.

  Even after cooling at −30 ° C. for 24 hours, it is preferable that the glass whose surface is coated does not peel or change its appearance. This is because when the film peels off or changes in appearance, sufficient alkali elution prevention performance cannot be obtained.

  The film thickness of the organic / inorganic hybrid coating material is preferably 0.1 to 2 μm. When the film thickness is 0.1 μm or less, elution of alkali components cannot be suppressed, which is not preferable. When the film thickness is 2 μm or more, unevenness and cracks are likely to occur on the film surface, which is not preferable.

(Example)
Hereinafter, the present invention will be described specifically by way of examples. The samples obtained in the examples and comparative examples were evaluated for quality by the following method.

    [Appearance evaluation]: The appearance of the sample and the presence or absence of cracks were visually evaluated. Those having no problem were evaluated as acceptable (◯), and those having problems were regarded as unacceptable (x).

  [Film Thickness Measurement] Immediately after coating, the film was peeled off in advance and baked, and the level difference from soda lime glass was measured using a stylus type surface roughness meter (manufactured by Kosaka Laboratory, ET4000A).

[Alkali dissolution test] Eight 50 mm × 60 mm samples (area 480 cm ² ) subjected to double-side coating were immersed in 100 cc of pure water and boiled in a hot bath at 100 ° C. for 1 hour. 10 ml of the obtained eluate was collected, and hydrochloric acid was added to make a total volume of 25 ml to obtain a measurement solution. The obtained measurement liquid was subjected to atomic absorption analysis (manufactured by Hitachi, Z-5000), and the elution amount of the sodium component was measured.

  [Transmittance Measurement] The transmission spectrum was measured using a spectrophotometer (Hitachi, U-4000). A sample having a transmittance in the ultraviolet region 300-380 nm of 50% or more and a transmittance in the visible light region 380-800 nm of 90% or more was evaluated as acceptable (◯).

  [Heat resistance test] The sample was heated in a baking furnace at 300 ° C for 24 hours, and the transmittance was measured.

  [Low temperature test] The sample was held at -30 ° C for 24 hours, and the appearance of the sample and the presence or absence of cracks were visually evaluated.

    The results are shown in Table 1.

Phenyltriethoxysilane 21.7ml at room temperature (PhSi _{(OEt) 3),} methyltriethoxysilane _{23.9ml (MeSi (OEt) 3)} , dimethyl diethoxy silane _{5.3ml (Me 2 Si (OEt)} 2 ), 12.6 ml vinyltriethoxysilane (ViSi (OEt) ₃ ), 108 ml water, 87.2 ml ethanol, 1.7 ml acetic acid. The mixed solution was heated at 100 ° C. for 4 hours and then heated under reduced pressure at 30 ° C. for 1 hour to obtain a precursor. The precursor was dissolved in isobutyl acetate to obtain a solution having a solid concentration of 10% by weight. This solution was dip-coated on a 2 mm thick soda lime glass surface at a lifting speed of 4 mm / sec and heated at 250 ° C. for 1 hour to produce a 0.3 μm thick colorless transparent film on the glass.

  As shown in Table 1, the film obtained by the above method was confirmed to be a film having a low alkali elution amount and excellent transmittance and heat resistance.

  A colorless transparent film having a thickness of 1.8 μm was produced on glass by performing the same operation as in Example 1 except that the solid content concentration was 20 wt%.

  As shown in Table 1, the film obtained by the above method was confirmed to be a film having a low alkali elution amount and excellent transmittance and heat resistance.

28.9 ml phenyltriethoxysilane (PhSi (OEt) ₃ ), 29.9 ml methyltriethoxysilane (MeSi (OEt) ₃ ), 6.7 ml tetraethoxysilane (Si (OEt) ₄ ), 108 ml at room temperature Of water, 87.2 ml ethanol, 1.7 ml acetic acid. The mixed solution was heated at 100 ° C. for 4 hours and then heated under reduced pressure at 30 ° C. for 1 hour to obtain a precursor. The precursor was dissolved in isobutyl acetate to obtain a solution having a solid concentration of 10% by weight. This solution was dip-coated on a 2 mm thick soda lime glass surface at a pulling rate of 4 mm / sec and heated at 250 ° C. for 1 hour to produce a 0.3 μm thick colorless and transparent film on the glass.

  As shown in Table 1, the film obtained by the above method was confirmed to be a film having a low alkali elution amount and excellent transmittance and heat resistance.

Phenyltriethoxysilane 28.9ml at room temperature (PhSi _{(OEt) 3),} methyltriethoxysilane _{29.8ml (MeSi (OEt) 3)} , dimethyl diethoxy silane _{5.3ml (Me 2 Si (OEt)} 2 ), 108 ml water, 87.2 ml ethanol, 1.7 ml acetic acid. The mixed solution was heated at 100 ° C. for 4 hours and then heated under reduced pressure at 30 ° C. for 1 hour to obtain a precursor. The precursor was dissolved in isobutyl acetate to obtain a solution having a solid concentration of 10% by weight. This solution was dip-coated on a 2 mm thick soda lime glass surface at a lifting speed of 4 mm / sec and heated at 250 ° C. for 1 hour to produce a 0.3 μm thick colorless transparent film on the glass.

  As shown in Table 1, the film obtained by the above method was confirmed to be a film having a low alkali elution amount and excellent transmittance and heat resistance.

At room temperature 36.2 ml phenyltriethoxysilane (PhSi (OEt) ₃ ), 29.9 ml methyltriethoxysilane (MeSi (OEt) ₃ ), 108 ml water, 87.2 ml ethanol, 1.7 ml acetic acid. Mixed. The mixed solution was heated at 100 ° C. for 4 hours and then heated under reduced pressure at 30 ° C. for 1 hour to obtain a precursor. The precursor was dissolved in isobutyl acetate to obtain a solution having a solid concentration of 10% by weight. This solution was dip-coated on a 2 mm thick soda lime glass surface at a lifting speed of 4 mm / sec and heated at 250 ° C. for 1 hour to produce a 0.3 μm thick colorless transparent film on the glass.

  As shown in Table 1, the film obtained by the above method was confirmed to be a film having a low alkali elution amount and excellent transmittance and heat resistance.

(Comparative Example 1)
A soda lime glass having a thickness of 2 mm was immersed in pure water at 100 ° C. for 1 hour, and the sodium component eluted in the pure water was determined by atomic absorption spectrometry. As a result, it was 0.21 μg / cm ² and 0.01 μg Since it exceeded / cm ² , it could not be used as a substitute substrate for non-alkali glass.

  The present invention can be used as a substrate for a display element such as a substrate for a TFT of a liquid crystal display or a substrate for an organic electroluminescence (organic EL) display. In addition, it can be used as a glass container which prevents alkali elution, such as a cosmetic bottle and a chemical bottle.

Claims (6)

An organic-inorganic hybrid substance (precursor) containing at least one organic substituent selected from the group consisting of aromatic or aromatic hydrocarbon groups, saturated hydrocarbon groups and unsaturated hydrocarbon groups and a siloxane bond is used as an organic solvent. It is an organic-inorganic hybrid coating material that dissolves in glass, coats and cures on the glass surface, coats the glass surface, and prevents elution of alkali components from the glass to water. 10% or more and 60% or less of an alkoxysilane containing a hydrocarbon group containing an aromatic or aromatic group, 20% or more and 80% or less of an alkoxysilane containing a saturated hydrocarbon group, an unsaturated hydrocarbon group The organic silane is characterized in that the alkoxysilane containing is 50% or less by mole ratio and the tetrafunctional alkoxysilane is 50% or less by mole ratio. Hybrid coating material. The organic-inorganic hybrid coating material according to claim 1, wherein the siloxane network contains a tetrafunctional group . The precursor is prepared by adding 10 to 50 times water, 10 times or less alcohol, and 0.001 to 1 times acid catalyst to alkoxysilane in a molar ratio, and heating the mixed solution at 50 to 110 ° C. for 1 hour to 1 week. The organic-inorganic hybrid coating material according to claim 1 , wherein the organic-inorganic hybrid coating material is synthesized . The organic-inorganic hybrid coating material according to any one of claims 1 to 3 , wherein the precursor is stabilized by heating under reduced pressure at 20 to 110 ° C for 5 minutes to 10 hours . The organic-inorganic hybrid coating material according to any one of claims 1 to 4 , wherein the precursor is dissolved in an organic solvent to form a solution having a solid content concentration of 3 to 30% by weight and applied to the glass surface. . The organic-inorganic hybrid coating material according to any one of claims 1 to 5 , wherein the organic-inorganic hybrid coating material is cured by heating at 100 to 500 ° C after application to the glass surface .