JP5716675B2 - Electrode protective film forming agent - Google Patents

Description

The present invention is used in a liquid crystal display device, the electrode protective film forming agent containing a polysiloxane, a liquid crystal display device having the electrode protection film and the electrode protective film.

In the production of a liquid crystal display element, an oxide film is formed between a transparent electrode and a liquid crystal alignment film for the purpose of insulating and protecting the transparent electrode. As a method for forming an oxide film, a gas phase method represented by a vapor deposition method, a sputtering method, and the like, and a coating method using a coating liquid for forming an oxide film are known. Of these, coating methods are often used because of productivity and ease of film formation on large substrates. Known coating liquids include hydrolysates of tetraalkoxysilane and composites with other metal alkoxides and metal chelate compounds. When a coating solution is prepared using a metal alkoxide, the metal alkoxide generally has a high hydrolysis rate except for silicon, and the reaction control is difficult. Therefore, attempts have been made to act a chelating agent such as acetylacetone for the purpose of adjusting the hydrolysis rate of the alkoxide. However, generally chelated compounds have a high thermal decomposition temperature, and firing at 450 ° C. or higher is desirable. (For example, refer to Patent Document 1.)
Another method is to add a mineral acid to the hydrolyzate of silicon alkoxide and titanium alkoxide in a silica-titania-based coating solution to obtain a transparent coating agent without using a stabilizing means such as chelation. Has been tried. Also in this case, firing at least at 300 ° C. is required. (For example, see Patent Document 2.)
Recently, a display using a plastic plate or a plastic film as a base material such as a plastic LCD or electronic paper has been proposed, and sufficient hardness can be obtained even at a low temperature of 200 ° C. or lower, and the upper alignment agent can be applied without defects. It has been demanded.

JP 63-258959 A JP-A-55-25487

In the methods of Patent Document 1 and Patent Document 2, it is difficult to obtain an electrode protective film having sufficient hardness at a firing temperature of 200 ° C. or lower. And when forming a liquid crystal aligning film on the upper layer of an electrode protective film, there exists a problem that a repelling and a pinhole generate | occur | produce in an alignment film.
An object of the present invention is to provide an electrode protective film forming agent capable of forming an electrode protective film having sufficient hardness even when fired at a low temperature of 150 ° C. or lower, an electrode protective film, and a liquid crystal display device having the electrode protective film. To do. When used for a liquid crystal display element , an object of the present invention is to provide an electrode protective film forming agent capable of forming a liquid crystal alignment film in which generation of repellency and pinholes is suppressed on the upper layer of the electrode protective film.

As a result of intensive studies in view of the above situation, the present inventors have completed the present invention.
That is, the gist of the present invention is as follows.
1. An electrode protective film forming agent for obtaining an electrode protective film for a liquid crystal display element in which a liquid crystal alignment film is formed on the upper layer of the electrode protective film , represented by alkoxysilane represented by formula (1) and formula (2) include alkoxysilane emissions to be, and alkoxysilane represented by the formula (1) is, in the total alkoxysilane, it contains 0.5 to 60 mol%, and the alkoxysilane of formula (2) is the total alkoxy An electrode protective film forming agent comprising polysiloxane obtained by polycondensation of alkoxysilane containing 40 to 99.5 mol% in silane .
R ¹ {Si (OR ² ) ₃ } _P (1)
(R ¹ is a C 1-12 hydrocarbon group substituted with a ureido group, R ² is a C 1-5 alkyl group, and p represents an integer of 1 or 2.)
(R ³ ) _n Si (OR ⁴ ) _4-n (2)
(R ³ is a hydrogen atom, or a hetero atom, a halogen atom, a vinyl group, an amino group, a glycidoxy group, a mercapto group, a methacryloxy group, an isocyanate group or an acryloxy group, and having 1 to 8 carbon atoms. A hydrocarbon group, R ⁴ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3.)
2. 2. The electrode protective film forming agent according to 1 above, wherein n in formula (2) is tetraalkoxysilane.
3. The alkoxysilane represented by the formula (1) is at least one selected from the group consisting of γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, and γ-ureidopropyltripropoxysilane. Or the electrode protective film forming agent of 2.
4). An electrode protective film for a liquid crystal display element, which is obtained by applying the electrode protective film forming agent according to any one of the above 1 to 3 to a substrate and baking it, and having a liquid crystal alignment film formed thereon .
5. 4. A method for forming an electrode protective film, wherein the electrode protective film forming agent according to any one of 1 to 3 is applied to a substrate, dried at a temperature of room temperature to 120 ° C., and then fired.
6). 6. The method for forming an electrode protective film according to 5 above, wherein the firing temperature is 100 to 180 ° C.
7). 5. A liquid crystal display device having the electrode protective film as described in 4 above.

  Since the electrode protective film obtained from the electrode protective film forming agent of the present invention has sufficient hardness under low temperature curing conditions of 150 ° C. or lower, it can be applied to substrates having low heat resistance such as plastic substrates. Moreover, when using for a liquid crystal display element, the liquid crystal aligning film which suppressed repellency and a pinhole can be formed on the formed electrode protective film. Therefore, even a substrate having low heat resistance such as a plastic substrate is useful for manufacturing a liquid crystal display element having excellent display characteristics.

The electrode protective film forming agent of the present invention is characterized in that it contains polysiloxane having a ureido group. Therefore, it is possible to form an electrode protective film having sufficient hardness even at a low temperature of 100 to 150 ° C.
Conventionally, an oxide thin film formed from a siloxane polymer or an oxide precursor does not sufficiently decompose alkoxy groups remaining in a coating film when the firing temperature is low. Therefore, when used in a liquid crystal display element, sufficient affinity and adhesion cannot be obtained with a polyimide-based alignment film having different interface characteristics, which may cause repellency and pinholes when forming the alignment film. Can be estimated. In the present invention, by containing a ureido group in the electrode protective film forming agent, the affinity with the polyimide-based alignment agent is improved, and not only the repellency and pinholes can be suppressed, but also the electrode protective film forming agent is 100 to 150 ° C. It is presumed that even when baked at a low temperature, it is sufficiently cured.
The present invention is described in detail below.

[Polysiloxane]
The electrode protective film forming agent of the present invention is a polysiloxane obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the following formula (1).
R ¹ {Si (OR ² ) ₃ } _P (1)
In formula (1), R ¹ is a hydrocarbon group having 1 to 12 carbon atoms substituted with a ureido group. More specifically, any hydrogen atom of a hydrocarbon group having 1 to 12 carbon atoms is converted to ureido. A group substituted with a group is represented. R ¹ is preferably 1 to 7 carbon atoms of a hydrocarbon group substituted with a ureido group. R ² is an alkyl group having 1 to 5 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group. p represents an integer of 1 or 2. R ¹ and R ² may have a linear structure or a branched structure.
In the alkoxysilane represented by the formula (1), when p is 1, it is an alkoxysilane represented by the formula (1-1).
R ¹ Si (OR ² ) ₃ (1-1)
Moreover, when p is 2, it is an alkoxysilane represented by Formula (1-2).
_{^{(R 2 O) 3 Si-}} R 1- Si (OR 2) 3 (1-2)
Although the specific example of the alkoxysilane represented by Formula (1-1) is given, it is not limited to these. For example, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltripropoxysilane, (R) -N-1-phenylethyl-N′-triethoxysilylpropylurea, (R) — N-1-phenylethyl-N′-trimethoxysilylpropylurea and the like can be mentioned.
Among these, γ-ureidopropyltriethoxysilane or γ-ureidopropyltrimethoxysilane is particularly preferable because it is easily available as a commercial product.
Although the specific example of the alkoxysilane represented by Formula (1-2) is given, it is not limited to these. For example, bis [3- (triethoxysilyl) propyl] urea, bis [3- (triethoxysilyl) ethyl] urea, bis [3- (trimethoxysilyl) propyl] urea, bis [3- (tripropoxysilyl) Propyl] urea and the like. Among these, bis [3- (triethoxysilyl) propyl] urea is particularly preferable because it is easily available as a commercial product.
When the alkoxysilane represented by the formula (1) is less than 0.5 mol% in all alkoxysilanes used for obtaining the electrode protective film forming agent, good printability of the liquid crystal alignment film cannot be obtained. In some cases, 0.5 mol% or more is preferable. More preferably, it is 1.0 mol% or more. More preferably, it is 2.0 mol% or more. Moreover, since it may not fully harden | cure the electrode protective film formed when it exceeds 60 mol%, 60 mol% or less is preferable. More preferably, it is 50 mol% or less. More preferably, it is 40 mol% or less.

Moreover, the electrode protective film forming agent of the present invention is obtained by polycondensing an alkoxysilane containing at least one of the alkoxysilanes represented by the following formula (2) together with the alkoxysilane represented by the formula (1). Can do.
(R ³ ) _n Si (OR ⁴ ) _4-n (2)
(R ³ is a hydrogen atom, or a hetero atom, a halogen atom, a vinyl group, an amino group, a glycidoxy group, a mercapto group, a methacryloxy group, an isocyanate group, or an acryloxy group, having 1 to 8 carbon atoms, Preferably, it is a hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and n is an integer of 0 to 3, preferably 0 to 2. Represents.)
R ³ of the alkoxysilane represented by the formula (2) is substituted with a hydrogen atom, a hetero atom, a halogen atom, a vinyl group, an amino group, a glycidoxy group, a mercapto group, a methacryloxy group, an isocyanate group or an acryloxy group. Or a hydrocarbon group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. R ⁴ has the same meaning as R ² described above, and the preferred range is also the same. Examples of R ³ include aliphatic hydrocarbons; ring structures such as aliphatic rings, aromatic rings or heterocycles; unsaturated bonds; heteroatoms such as oxygen atoms, nitrogen atoms, sulfur atoms, etc. It is an organic group having 1 to 6 carbon atoms that may have a branched structure. In addition, R ³ may be substituted with a halogen atom, a vinyl group, an amino group, a glycidoxy group, a mercapto group, a methacryloxy group, an isocyanate group, an acryloxy group, or the like.

Although the specific example of the alkoxysilane represented by such Formula (2) below is given, it is not limited to this.
In the alkoxysilane of the formula (2), specific examples of the alkoxysilane when R ³ is a hydrogen atom include trimethoxysilane, triethoxysilane, tripropoxysilane, tributoxysilane and the like.
Other specific examples of the alkoxysilane of formula (2) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and methyltripropoxy. Silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, 2- (2-aminoethylthioethyl) triethoxysilane, 3-mel Ptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, allyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyl Trimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, trifluoropropyltrimethoxysilane, chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldi Ethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, diphenyl Silane, 3-aminopropyl methyl diethoxy silane, 3-aminopropyl dimethylethoxysilane, trimethylethoxysilane, trimethylmethoxysilane and the like.

The electrode protective film forming agent of the present invention may be one kind of such a specific organic group as long as the effects of the present invention are not impaired, such as adhesion to the substrate, film hardness, and printability of the upper liquid crystal alignment film. You may have multiple types.
In the alkoxysilane represented by the formula (2), the alkoxysilane in which n is 0 is tetraalkoxysilane. Tetraalkoxysilane is preferable for obtaining the polysiloxane of the present invention because it easily condenses with the alkoxysilane represented by the formula (1).
As the alkoxysilane in which n is 0 in the formula (2), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable.
When using together the alkoxysilane represented by Formula (2), in all the alkoxysilanes used in order to obtain an electrode protective film formation agent, the alkoxysilane represented by Formula (2) is 40-99.5 mol%. Preferably there is. More preferably, it is 50-99.5 mol%. More preferably, it is 60-99.5 mol%.
In the present invention, the electrode protective film forming agent is a polysiloxane obtained by polycondensation of an alkoxysilane represented by the formula (1) and at least one compound selected from the alkoxysilanes represented by the formula (2). It is preferable that
As long as the electrode protective film forming agent of the present invention does not impair the effects of the present invention such as the hardness of the film and the printability of the upper liquid crystal alignment film, one or more kinds of such alkoxysilanes may be used in combination. Good.

[Production method of polysiloxane]
The method for obtaining the polysiloxane used in the present invention is not particularly limited. In the present invention, the polysiloxane can be obtained by condensing the alkoxysilane having the above-described alkoxysilane of the formula (1) as an essential component in an organic solvent. Usually, polysiloxane is obtained as a solution obtained by polycondensation of such alkoxysilanes and uniformly dissolved in an organic solvent.
Examples of the polycondensation method in the present invention include a method of hydrolyzing and condensing the alkoxysilane in a solvent such as alcohol or glycol. At that time, the hydrolysis / condensation reaction may be either partial hydrolysis or complete hydrolysis. In the case of complete hydrolysis, theoretically, it is sufficient to add 0.5 moles of water of all alkoxide groups in the alkoxysilane, but it is usually preferable to add an excess amount of water over 0.5 moles.
In the present invention, the amount of water used in the above reaction can be appropriately selected as desired, but usually it is preferably 0.5 to 2.5 times the total number of alkoxy groups in the alkoxysilane, more Preferably it is 0.75-1.5 times mole.
Usually, for the purpose of promoting hydrolysis / condensation reaction, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, succinic acid, maleic acid, fumaric acid; alkalis such as ammonia, methylamine, ethylamine, ethanolamine, triethylamine Catalysts such as metal salts such as hydrochloric acid, sulfuric acid and nitric acid are used. In addition, it is also common to further promote the hydrolysis / condensation reaction by heating the solution in which the alkoxysilane is dissolved. At that time, the heating temperature and the heating time can be appropriately selected as desired. For example, heating and stirring at 50 ° C. for 24 hours, heating and stirring for 1 hour under reflux, and the like can be mentioned.
As another method, a method of heating and polycondensing a mixture of an alkoxysilane, a solvent, and an organic acid such as formic acid, oxalic acid, maleic acid, and fumaric acid can be used. For example, a method of polycondensation by heating a mixture of alkoxysilane, solvent and oxalic acid can be mentioned. Specifically, after adding succinic acid to alcohol in advance to make an alcohol solution of succinic acid, alkoxysilane is mixed while the solution is heated. In that case, it is preferable that the quantity of the oxalic acid to be used shall be 0.2-2 mol with respect to 1 mol of all the alkoxy groups which alkoxysilane has. Heating in this method can be performed at a liquid temperature of 50 to 180 ° C. Preferably, it is a method of heating for several tens of minutes to several tens of hours under reflux so that the liquid does not evaporate or volatilize.

When using multiple types of alkoxysilane when obtaining polysiloxane, you may use it as a mixture which mixed multiple types of alkoxysilane previously, and may mix and use multiple types of alkoxysilane sequentially.
The solvent used for polycondensation of alkoxysilane (hereinafter also referred to as polymerization solvent) is not particularly limited as long as it can dissolve alkoxysilane. Moreover, even when alkoxysilane does not melt | dissolve, what is melt | dissolved should just melt | dissolve with the progress of the polycondensation reaction of alkoxysilane. In general, since an alcohol is generated by a polycondensation reaction of alkoxysilane, an alcohol, a glycol, a glycol ether, or an organic solvent having good compatibility with the alcohol is used.

  Specific examples of such a polymerization solvent include alcohols such as methanol, ethanol, propanol, butanol, diacetone alcohol; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1 Glycols such as 1,5-pentanediol, 2,4-pentanediol, 2,3-pentanediol, 1,6-hexanediol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether , Ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , Diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, Glycol ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether; N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, γ-butyrolactone , Dimethyl sulfoxide, tetramethylurea, hexamethylphosphotriamide, m-cresol and the like.

In the present invention, a plurality of the above polymerization solvents may be mixed and used.
The polysiloxane polymerization solution (hereinafter also referred to as polymerization solution) obtained by the above method is a concentration obtained by converting silicon atoms of all alkoxysilanes charged as raw materials into SiO ₂ (hereinafter referred to as SiO ₂ conversion concentration). ) Is generally 20% by mass or less. By selecting an arbitrary concentration within this concentration range, gel formation can be suppressed and a homogeneous solution can be obtained.
In the present invention, the polysiloxane polymerization solution obtained by the above method may be used as an electrode protective film forming agent as it is, and if necessary, the solution obtained by the above method may be concentrated or a solvent may be used. In addition, it may be diluted or replaced with another solvent to form an electrode protective film forming agent.
In that case, the solvent to be used (hereinafter also referred to as additive solvent) may be the same as the polymerization solvent, or may be another solvent. The additive solvent is not particularly limited as long as the polysiloxane is uniformly dissolved, and one kind or plural kinds can be arbitrarily selected and used.
Specific examples of such an additive solvent include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate, and ethyl lactate in addition to the solvents mentioned as examples of the polymerization solvent. It is done.
These solvents can improve the coating property when the electrode protective film forming agent is applied onto the substrate by adjusting the viscosity of the electrode protective film forming agent or by spin coating, flexographic printing, ink jetting, slit coating or the like.

[Other ingredients]
In the present invention, as long as the effects of the present invention are not impaired, other components other than the above polysiloxane, for example, inorganic fine particles, metalloxane oligomers, metalloxane polymers, leveling agents, and surfactants are included. It may be.
As the inorganic fine particles, fine particles such as silica fine particles, alumina fine particles, titania fine particles, or magnesium fluoride fine particles are preferable, and those in a colloidal solution state are particularly preferable. This colloidal solution may be a dispersion of inorganic fine particles in a dispersion medium, or a commercially available colloidal solution. In the present invention, by containing inorganic fine particles, it is possible to adjust the surface shape and refractive index of the formed cured film and to provide other functions. The inorganic fine particles preferably have an average particle size of 0.001 to 0.2 μm, more preferably 0.001 to 0.1 μm. When the average particle diameter of the inorganic fine particles exceeds 0.2 μm, the transparency of the cured film formed using the prepared coating liquid may be lowered.

Examples of the dispersion medium for the inorganic fine particles include water and organic solvents. As a colloid solution, it is preferable that pH or pKa is adjusted to 1-10 from a viewpoint of stability of an electrode protective film formation agent. The pH or pKa is more preferably 2-7.
Examples of the organic solvent used for the dispersion medium of the colloidal solution include alcohols such as methanol, propanol, butanol, ethylene glycol, propylene glycol, butanediol, pentanediol, hexylene glycol, diethylene glycol, dipropylene glycol, and ethylene glycol monopropyl ether; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; esters such as ethyl acetate, butyl acetate and γ-butyrolactone; Examples include ethers such as tetrahydrofuran and 1,4-dioxane. Of these, alcohols and ketones are preferred. These organic solvents can be used alone or in admixture of two or more as a dispersion medium.

As the metalloxane oligomer and the metalloxane polymer, single or composite oxide precursors such as silicon, titanium, aluminum, tantalum, antimony, bismuth, tin, indium, and zinc are used. As metalloxane oligomers and metalloxane polymers, even those that are commercially available can be obtained by processing from monomers such as metal alkoxides, nitrates, hydrochlorides, and carboxylates by conventional methods such as hydrolysis. There may be.
Specific examples of commercially available metalloxane oligomers and metalloxane polymers include siloxane oligomers or siloxanes such as methyl silicate 51, methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, EMS-485, and SS-101 manufactured by Colcoat. Examples thereof include titanoxane oligomers such as a polymer and titanium-n-butoxide tetramer manufactured by Kanto Chemical Co., Inc. You may use these individually or in mixture of 2 or more types.
Moreover, a leveling agent, surfactant, etc. can use a well-known thing, and since a commercial item is easy to acquire especially, it is preferable.
Moreover, the method of mixing the above-mentioned other components with polysiloxane may be simultaneous with or after polysiloxane, and is not particularly limited.

[Electrode protective film]
A desired electrode protective film can be obtained by applying the electrode protective film forming agent of the present invention to an electrode or a substrate with an electrode, followed by thermosetting. As a method for applying the electrode protective film forming agent, a known or well-known method can be adopted. For example, a dip method, a flow coating method, a spray method, a bar coating method, a gravure coating method, a roll coating method, a blade coating method, an air knife coating method, a flexographic printing method, an ink jet method, a slit coating method and the like can be employed. Among these, a favorable coating film can be formed in the flexographic printing method, the slit coating method, the inkjet method, the spray coating method, and the gravure coating method.
In that case, examples of the base material used include plastics; glass; glass with a transparent electrode such as ATO, FTO (fluorine-doped tin oxide), ITO, IZO; and base materials such as ceramics. Plastics include polycarbonate, poly (meth) acrylate, polyethersulfone, polyarylate, polyurethane, polysulfone, polyether, polyetherketone, polyolefin, polyethylene terephthalate, polyacrylonitrile, triacetylcellulose, diacetylcellulose, acetate butyratecellulose Etc. Examples of the shape of the substrate include a plate or a film.

The electrode protective film forming agent is generally filtered using a filter or the like before coating.
The coating film formed on the substrate is dried at a temperature of room temperature to 120 ° C., preferably 60 to 90 ° C., and then thermally cured at a temperature of 100 to 180 ° C., more preferably 150 to 180 ° C. At this time, the time required for drying may be 30 seconds or more, but 10 minutes or less is sufficient.
The time required for thermosetting can be selected as appropriate, but may be 5 minutes or longer. When selecting a low curing temperature, it is easy to obtain an electrode protective film having sufficient hardness by increasing the curing time.
In addition, the electrode protective film formation agent of this invention can obtain the cured film which has sufficient hardness even if it is the curing temperature over 180 degreeC.
It is also effective to irradiate energy rays (ultraviolet rays or the like) using a mercury lamp, a metal halide lamp, a xenon lamp, an excimer lamp or the like prior to thermosetting. By irradiating the dried coating with energy rays, the curing temperature can be further lowered, or the hardness of the coating can be increased. The irradiation amount of energy rays can be appropriately selected as necessary, but usually several hundred to several thousand mJ / cm ² is appropriate.
Since the electrode protective film of the present invention has good printability of the liquid crystal alignment material on the coating film, it can form a liquid crystal alignment film in which repelling and pinholes are suppressed.
Therefore, the electrode protective film forming agent of the present invention can form an electrode protective film having the above-described characteristics, and is thus very useful for improving the display characteristics of liquid crystal display elements.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
In this example, the abbreviations of the compounds used are as follows.
TEOS: Tetraethoxysilane APS: 3-aminopropyltriethoxysilane GPS: 3-glycidoxypropyltrimethoxysilane MPS: 3-mercaptopropyltrimethoxysilane UPS: 3-ureidopropyltriethoxysilane MPMS: 3-methacryloxypropyl Trimethoxysilane TET: Tetraethoxytitanium AN: Aluminum nitrate nonahydrate HG: Hexylene glycol (also known as 2-methyl-2,4-pentanediol)
PGME: Propylene glycol monomethyl ether (also known as 1-methoxy-2-propanol)
BCS: Butyl cellosolve (alias: 1-butoxy-2-ethanol)
PB: Propylene glycol monobutyl ether (alias: 1-butoxy-2-propanol)
NMP: N-methyl-2-pyrrolidone 1,4-BDO: 1,4-butanediol MeOH: methanol EtOH: ethanol

[Synthesis Example 1]
A methanol solution of oxalic acid was prepared by charging 39.0 g of MeOH into a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, and adding 18.0 g of oxalic acid to this MeOH little by little under stirring. The solution was then heated to its reflux temperature, and 10.4 g of tetraethoxysilane, 1.1 g of APS, 2.4 g of GPS, 1.0 g of MPS, and 8.6 g of a methanol solution containing 92% UPS (in this solution under reflux) A mixture of UPS content: 7.9 g) and MeOH 19.5 g was added dropwise over 45 minutes. Even after completion of the dropwise addition, heating was continued for 5 hours under reflux, followed by cooling to prepare a polysiloxane solution (L1).
Further, in a 300 ml flask, 100 g of the polysiloxane solution L1 was mixed with HG 64.0 g, NMP 48.0 g, 1, and 4-BDO 32.0 g as solvents. Next, the solvent was distilled off while gradually reducing the pressure to 20 mmHg (2.67 kPa) at 60 ° C. using a NEW rotary vacuum evaporator (manufactured by Tokyo Rika Kikai Co., Ltd., NE-1), and 184.0 g of the solvent was replaced with NMP. Solution (hereinafter also referred to as a replacement solution) was obtained. Then, by mixing PGME16.0g to the substitution solution 184.0 g, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane solution (LA1).

[Synthesis Example 2]
A 200 ml four-necked reaction flask equipped with a thermometer and a reflux tube was charged with 39.6 g of MeOH, 27.8 g of TEOS, and 9.6 g of a methanol solution containing 92% of UPS (UPS content: 8.8 g). Then, a solution of the alkoxysilane monomer was prepared. A solution prepared by previously mixing 17.64 g of MeOH, 9.00 g of water and 1.50 g of oxalic acid as a catalyst was added dropwise to this solution over 30 minutes at room temperature, and the mixture was stirred at room temperature for 30 minutes after the completion of the addition. Then, after heating for 1 hour under reflux, the mixture was allowed to cool to obtain a polysiloxane solution having a solid content concentration in terms of SiO ₂ of 10% by mass.
To polysiloxane solution 30.0g obtained by mixing HG35.0g and BCS35.0G, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane dilute solution (LA2).

[Synthesis Example 3]
A 200 ml four-necked reaction flask equipped with a thermometer and a reflux tube was charged with 31.8 g of PGME and 33.0 g of TEOS and stirred to prepare an alkoxysilane monomer solution. To this solution, a solution in which 15.9 g of PGME, 15.0 g of water and 0.2 g of oxalic acid as a catalyst were mixed in advance was added dropwise over 30 minutes at room temperature, and stirred at room temperature for 30 minutes after completion of the addition. Then, after heating for 30 minutes under reflux, a solution prepared by mixing 2.4 g of a methanol solution containing 92% UPS (UPS content: 2.2 g) and 1.8 g of PGME was added, and further heated under reflux for 30 minutes. after, SiO ₂ in terms of solid concentration was obtained 10 wt% of the polysiloxane solution was allowed to cool.
The obtained polysiloxane solution 30.0g, PGME60.0g, and mixed HG10.0G, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane dilute solution (LA3).

[Synthesis Example 4]
A 200 ml four-neck reaction flask equipped with a thermometer and a reflux tube was charged with 31.5 g of PGME, 31.2 g of TEOS, and 2.1 g of MPMS, and stirred to prepare an alkoxysilane monomer solution. A solution prepared by previously mixing 15.7 g of PGME, 15.0 g of water and 0.3 g of oxalic acid as a catalyst was added dropwise to this solution over 30 minutes at room temperature, and the mixture was stirred at room temperature for 30 minutes after completion of the addition. Then, after heating for 30 minutes under reflux, a solution prepared by mixing 2.4 g of a methanol solution containing 92% UPS (UPS content: 2.2 g) and 1.8 g of PGME was added, and further heated under reflux for 30 minutes. after, SiO ₂ in terms of solid concentration was obtained 10 wt% of the polysiloxane solution was allowed to cool.
The obtained polysiloxane solution 30.0g, PGME60.0g, and mixed HG10.0G, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane dilute solution (LA4).

[Synthesis Example 5]
A 200 ml four-necked reaction flask equipped with a thermometer and a reflux tube was charged with 20.6 g of HG, 6.9 g of BCS, and 37.5 g of TEOS, and stirred to prepare an alkoxysilane monomer solution. To this solution, a solution prepared by previously mixing 10.3 g of HG, 3.4 g of BCS, 10.8 g of water and 0.5 g of oxalic acid as a catalyst was added dropwise over 30 minutes at room temperature, and stirred at room temperature for 30 minutes after completion of the addition. . Then, after heating for 30 minutes under reflux, a solution in which 5.8 g of methanol solution containing 92% of UPS (UPS content: 5.3 g), 3.2 g of HG, and 1.1 g of BCS was added and further refluxed. After heating for 30 minutes, the mixture was allowed to cool to obtain a polysiloxane solution having a solid content concentration in terms of SiO ₂ of 12% by mass.
To polysiloxane solution 30.0g obtained, HG41.9g, mixed BCS7.1g and PB40.9G, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane dilute solution (LA5).

[Synthesis Example 6]
90 g of polysiloxane solution LA2 obtained in Synthesis Example 2, 3.0 g of colloidal silica fine particles (product name: methanol silica sol, manufactured by Nissan Chemical Industries, Ltd .; solid content concentration in terms of SiO ₂ is 30% by mass), and MeOH 7.0 g Was stirred at room temperature for 30 minutes to obtain a polysiloxane diluted solution (LA6) having a solid content concentration in terms of SiO ₂ of 3% by mass.

[Comparative Synthesis Example 1]
A 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube was charged with 40.3 g of EtOH, and 18.0 g of oxalic acid was added little by little to this EtOH with stirring to prepare an ethanol solution of oxalic acid. . The solution was then heated to its reflux temperature and a mixture of 20.8 g TEOS and 20.8 g EtOH was added dropwise over 45 minutes to the solution under reflux. Even after completion of the dropwise addition, heating was continued for 5 hours under reflux, followed by cooling to prepare a polysiloxane solution.
Furthermore, in a 300 ml flask, 100 g of this polysiloxane solution was mixed with 64.0 g of HG, 48.0 g of NMP, and 32.0 g of 1,4-BDO as solvents. Next, the solvent was distilled off with a NEW rotary vacuum evaporator (manufactured by Tokyo Rika Kikai Co., Ltd., NE-1) at 60 ° C. while gradually reducing the pressure to 20 mmHg (2.67 kPa) to obtain 184.0 g of a replacement solution. . Then, by mixing PGME16.0g to the substitution solution 184.0 g, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane solution (LB1).

[Comparative Synthesis Example 2]
A 200 ml four-neck reaction flask equipped with a thermometer and a reflux tube was charged with 23.7 g of HG, 7.9 g of BCS, and 41.7 g of TEOS, and stirred to prepare an alkoxysilane monomer solution. To this solution, a solution in which 11.8 g of HG, 3.9 g of BCS, 10.8 g of water and 0.2 g of oxalic acid as a catalyst were mixed dropwise over 30 minutes at room temperature, and stirred at room temperature for 30 minutes after completion of the dropwise addition. . Then, after heating for 60 minutes under reflux, the mixture was allowed to cool to obtain a polysiloxane solution having a solid content concentration in terms of SiO ₂ of 12% by mass.
To polysiloxane solution 30.0g obtained, HG55.2g, mixed BCS9.2g and PB55.6G, was obtained in terms of SiO ₂ solid content concentration of 3 mass% of a polysiloxane dilute solution (LB2).

[Comparative Synthesis Example 3]
A 300 ml flask was charged with 2.5 g of pure water, 64.8 g of ethanol and 2.7 g of AN as a catalyst, and stirred to obtain a uniform solution. To this solution, 14.3 g of TEOS was added and stirred at room temperature for 30 minutes. Thereafter, 15.7 g of TET was added and stirred at room temperature for 30 minutes. This solution was used as a solution before replacing the solvent with HG (pre-substitution solution).
Furthermore, 24.0 g of the obtained pre-substitution solution and HG 25.87 g were mixed in a 300 ml flask. Next, the solvent was distilled off while gradually reducing the pressure to 20 mmHg (2.67 kPa) at 60 ° C. with a NEW rotary vacuum evaporator (manufactured by Tokyo Rika Kikai Co., Ltd., NE-1) to obtain 28.9 g of a replacement solution. . Thereafter, 11.1 g of PGME was mixed with 28.9 g of the replacement solution to prepare a polytitanosiloxane solution (LB3) having a solid content concentration in terms of SiO ₂ of mass%.

[Evaluation of electrode protection film]
About the electrode protective film formed from the obtained solution (LA1-LA6) and (LB1-LB3), pencil hardness, a water contact angle, and liquid crystal aligning film printability were evaluated using the method mentioned later. The results are shown in Table 1.

From the results of Table 1, the electrode protective film obtained by the present invention is generally sufficient when the film is used as an electrode protective film (insulating film) of a liquid crystal display element even at a curing temperature as low as 150 ° C. or less. It showed a pencil hardness of 5H or higher, which is considered to be a high hardness.
And even if it was a case where not only a polyamic-acid type but a soluble polyimide type liquid crystal aligning agent was used on this film, the outstanding film formability without a repellency and a pinhole was shown.

[Pencil hardness]
The polysiloxane solutions (coating solutions) of Synthesis Examples (LA1 to LA6) and Comparative Synthesis Examples (LB1 to LB3) were filtered using a chromatodisc (manufactured by Kurashiki Boseki Co., Ltd., pore size: 0.45 μm). Then, it is dropped on a 0.7 mm thick glass substrate with ITO (ITO film thickness is 140 nm) and pre-rotated for 5 seconds at a rotation speed of 300 rpm using a spin coater (Mikasa 1H-DX2). After that, the coating film was formed by rotating at a rotational speed of 2000 to 5000 rpm for 20 seconds. Next, after drying on a hot plate at a temperature of 80 ° C. for 3 minutes, the cured film was obtained by heating on the hot plate at a curing temperature of 150 ° C. for 15 minutes. The pencil hardness of the obtained cured film was measured according to a test method (JIS K5400).

[Water contact angle]
Using an automatic contact angle meter CA-Z type manufactured by Kyowa Interface Science Co., Ltd., the contact angle when 3 microliters of pure water was dropped was measured. In addition, the aspect of the board | substrate used and the preparation methods of a protective film are the same as the case of the measurement of [pencil hardness].

[Liquid crystal alignment film printability]
On the cured film formed by the same method as the above [pencil hardness], using an S15 type printing machine (manufactured by Iinuma Gauge Mfg. Co., Ltd., anilox roll (300 #), letterpress (halftone dot 400L 30% 75 °)), Liquid crystal aligning agent (manufactured by Nissan Chemical Industries, Ltd., Sun Ever (registered trademark) SE-3140 0735 (trade name; polyamic acid type), SE-7492 062M (trade name; polyamic acid / soluble polyimide blend type), SE-5291 062B ( Product name; soluble polyimide type)) was applied. Then, it dried for 3 minutes on the hotplate of temperature 80 degreeC, and formed the liquid crystal aligning film. Visually observe the formed liquid crystal alignment film, repel the liquid crystal alignment film, ◯ if there is no pinhole or unevenness, △ if pinhole or unevenness is generated, The state where no film was formed was marked with x.

The electrode protective film forming agent of the present invention forms an electrode protective film that is excellent in coating film forming ability in flexographic printing method, slit coating method, ink jet method, spray coating method, and gravure coating method, and can be sufficiently cured at low temperature. I can. Furthermore, the formed electrode protective film can form a liquid crystal alignment film in which repelling and pinholes are suppressed on the upper layer. Therefore, it is useful as an electrode protective film for a liquid crystal display device using a plastic substrate that needs to be fired at a low temperature or a liquid crystal electronic paper.
It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2009-274661 filed on Dec. 02, 2009 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (7)

An electrode protective film forming agent for obtaining an electrode protective film for a liquid crystal display element in which a liquid crystal alignment film is formed on the upper layer of the electrode protective film , represented by alkoxysilane represented by formula (1) and formula (2) alkoxysilane alkoxysilane down only contains, and is expressed by the formula (1) to be found in the total alkoxysilane, it contains 0.5 to 60 mol%, and the alkoxysilane of formula (2) All An electrode protective film-forming agent comprising polysiloxane obtained by polycondensation of alkoxysilane containing 40 to 99.5 mol% in alkoxysilane .
R ¹ {Si (OR ² ) ₃ } _P (1)
(R ¹ is a C 1-12 hydrocarbon group substituted with a ureido group, R ² is a C 1-5 alkyl group, and p represents an integer of 1 or 2.)
(R ³ ) _n Si (OR ⁴ ) _4-n (2)
(R ³ is a hydrogen atom, or a hetero atom, a halogen atom, a vinyl group, an amino group, a glycidoxy group, a mercapto group, a methacryloxy group, an isocyanate group or an acryloxy group, and having 1 to 8 carbon atoms. A hydrocarbon group, R ⁴ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3.)   The electrode protective film forming agent according to claim 1, which is tetraalkoxysilane in which n in Formula (2) is 0. The alkoxysilane represented by the formula (1) is at least one selected from the group consisting of γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, and γ-ureidopropyltripropoxysilane. 3. The electrode protective film forming agent according to 1 or 2 . The electrode protective film for liquid crystal display elements by which the liquid crystal aligning film is formed in the upper layer obtained by apply | coating the electrode protective film forming agent in any one of Claims 1-3 to a board | substrate, and baking. It claims an electrode protective film formation agent according to any one of claim 1 to 3 is applied to a substrate and dried at a temperature of room temperature to 120 ° C., the method of forming the fired electrode protective film. The formation method of the electrode protective film of Claim 5 whose baking temperature is 100-180 degreeC. The liquid crystal display element which has an electrode protective film of Claim 4 .