JPH0360353B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for forming a titanium oxide thin film, and more specifically, a titanium oxide thin film used for manufacturing an optical interference film in which a titanium oxide thin film and a transparent metal oxide thin film other than titanium oxide are formed in multiple layers. The present invention relates to a forming composition and a method for producing an optical interference film using the composition. Titanium oxide thin films formed on heat-resistant substrates such as glass, metals, and ceramics have high transparency and refractive index, as well as excellent corrosion resistance, abrasion resistance, and decorative properties, so they are widely used. used in the field. In particular, multilayer films made by alternately laminating titanium oxide thin films and low refractive index thin films such as silicon oxide exhibit optical interference, and depending on the lamination mode, they can be used as mirrors or solar heat collectors as light reflective or antireflective films. Used in thermal mirrors, optical filters, cold mirrors, solar cells, etc. These optical interference films are required to have high transparency, uniform thickness, and good interlayer adhesion. For example, a light reflecting film can be obtained by forming a transparent thin film having a film thickness expressed by the following formula (1) on a substrate. Q=On/4n...(1) (Here, Q=film thickness, n: refractive index of the thin film. On: represents the wavelength of light that is the center of reflection.) Method for forming a titanium oxide thin film on a substrate As,
Vacuum deposition methods, sputtering methods, CVD methods, etc. using titanium metal or titanium compounds such as titanium oxide, titanium tetrachloride, etc., and solutions containing solvent-soluble organic titanium compounds can be applied by spray methods, spinner methods, immersion pulling methods, etc. There is a coating method in which the material is applied onto a substrate by a brush coating method, a printing method, etc., and then heated and burned, and the coating method is adopted as a method for processing a large amount at low cost. The coating liquid used in the coating method is usually
Titanium alkoxides represented by the general formula Ti(OR) ₄ (herein, R represents a monovalent hydrocarbon group),
For example, organic solvent solutions such as tetraisopropoxytitanium and tetrabutoxytitanium are used.
Titanium alkoxides are highly hydrolyzable, so they absorb moisture in the air and are easily hydrolyzed, making the coating solution cloudy and highly viscous, resulting in extremely poor stability and difficulty in handling. To improve these shortcomings, Japanese Patent Application Laid-Open No. 1983
Publication No. 200471 proposes a coating liquid in which titanium alkoxides are stabilized using chelating agents such as acetylacetone and methyl acetoacetate, alcohols, acetic esters, and the like as solvents.
However, in this method, although the moisture resistance stability of the coating solution is improved, the film forming properties of the titanium oxide thin film are poor, and the refractive index of the obtained titanium oxide thin film is also low. JP-A-49-122520 proposes that the coating liquid be an organic solvent solution containing a titanium alkoxide polymer obtained by adding water to titanium alkoxides and polymerizing them. Although the coating liquid of the invention is excellent in forming a titanium oxide thin film, clouding due to the influence of humidity has not been improved. Unexamined Japanese Patent Publication 1973
Publication No. 43241 proposes a coating solution in which water is added to thian alkoxides to polymerize them, and further stabilized using a chelating agent such as acetylacetone. The coating liquid has excellent moisture stability, and also has excellent film formability when a single layer of a titanium oxide thin film is formed using the coating liquid. However, when obtaining a multilayer film with different types of metal oxide thin films, such as silicon oxide thin films, in order to obtain an optical interference film,
It has a drawback of poor interlayer adhesion between the titanium oxide thin film and the dissimilar metal oxide thin film. The present invention is suitable for producing an optical interference film by a coating method, that is, it is stable and has excellent film formability, particularly has good interlayer adhesion with a thin film of a dissimilar metal oxide, and has a high refractive index. It is an object of the present invention to provide a composition for forming a titanium oxide thin film from which a titanium oxide thin film can be obtained, and another object is to provide a method for producing an optical interference film using the composition. As a result of intensive research to achieve the above object, the present inventors have developed a composition containing a mixture of itan alkoxide monomers and a polymer obtained by polymerizing them with a compound stabilized with a chelating agent. By using an organic solvent solution as a coating liquid, a titanium oxide thin film with a uniform thickness and high refractive index can be obtained, and it also has excellent interlayer adhesion when formed into a multilayer film with a silicon oxide thin film. They discovered this and completed the present invention. The present invention relates to a part of the alkoxy group of titanium alkoxides represented by the general formula: Ti(OR) ₄ ... [] (wherein R represents a monovalent hydrocarbon group having 1 to 18 carbon atoms) or all of the carboxylic acid residues of carboxylic acids represented by the general formula: HOCOR'...[] -
OCOR' (here, R' represents a monovalent hydrocarbon group having 1 to 18 carbon atoms) and the residue of organic compounds that can form a chelate ring with titanium represented by the general formula: HX...[] Group: Organic titanium compound substituted with one or more selected from the group of -X A: 5
to 50 parts by weight, and a substituent of a titanium alkoxide polymer obtained by hydropolymerizing the same or different titanium alkoxides represented by the general formula []: Part or all of -OR is represented by the general formula [] Residues of carboxylic acids: -OCOR' and residues of organic compounds capable of forming a chelate ring with titanium represented by the general formula []: organic compounds substituted with one or more selected from the group of -X. This is a composition for forming a titanium oxide thin film, comprising an organic solvent solution containing a mixture of 95 to 50 parts by weight of titanium compound B. In the present invention, the organic titanium compound A is a titanium alkoxide represented by the general formula []Ti(OR) ₄ , such as tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium,
Part or all of the alkoxy group such as tetrabutoxytitanium, diethoxydiisopropoxytitanium, dimethoxydibutoxytitanium, etc., can be replaced by the general formula []
Carboxylic acids represented by HOCOR′ such as acetic acid, propionic acid, butyric acid residues:
-OCOR' and/or organic compounds capable of forming a chelate ring with titanium represented by the general formula []HX, such as β-diketones such as acetylacetone and benzoylacetone, α- such as acetoacetic acid and propionylbutyric acid, Or, β-keto acids, lower alkyl esters of keto acids such as methyl, ethyl, propyl, butyl, oxyacids such as glycolic acid and lactic acid, lower alkyl esters of oxyacids such as methyl, ethyl, propyl, butyl, Residues of chelating agents such as diols and amino alcohols: Compounds substituted with -X For example, diisopropoxy titanium diisostearate, diisobutoxy bis(lactate) titanium, diisopropoxy bis(acetyl acetonato) titanium, dibutoxy bis(acetylacetonato) titanium, etc. Some or all of the alkoxy groups of titanium alkoxides are replaced with carboxylic acid residues and/or
Alternatively, the organotitanium compound A substituted with a chelating agent residue can be easily produced by reacting a titanium alkoxide with a carboxylic acid and/or a chelating agent in the presence or absence of an organic solvent. can. On the other hand, organic titanium compound polymer B is a titanium compound having a degree of polymerization n of 2 to 50 obtained by reacting the same or different titanium alkoxides represented by the general formula [] with a desired stoichiometric amount of water. In the alkoxide polymer, a carboxylic acid represented by the general formula [] and/or a general formula []
It is obtained by reacting titanium represented by the formula with a chelating agent capable of forming a chelate ring. As the organic titanium compound polymer B, the degree of polymerization n is 2
-50, preferably 2-20 are used. In the present invention, the composition for forming a titanium oxide thin film is obtained by converting a mixture consisting of 5 to 50 parts by weight of the organic compound A and 95 to 50 parts by weight of the organic titanium compound polymer B into titanium oxide (TiO _{2 )} . It is an organic solvent solution containing 20% by weight or less, preferably 1 to 10% by weight. In addition, glass forming agents such as inorganic or organic phosphorus compounds, boron compounds, arsenic compounds, antimony compounds, tin compounds, zinc compounds, lead compounds,
Also included are compounds containing one or more of potassium compounds, nickel nitrate, cobalt nitrate, and the like. Any organic solvent can be used as long as it can dissolve both the organic titanium compound A and the organic titanium compound polymer B used, but the volatility of the solvent, the stability of the solution, and the economic efficiency may be used. Lower alcohols with a boiling point of 180℃ or less,
A single solvent or a mixed solvent of two or more of these halides is preferably used. In the present invention, an organic solvent solution containing a mixture of organic titanium compound A and organic titanium compound B is used as a coating liquid, and is applied to a heat-resistant base material such as glass, metal, or ceramics to a uniform thickness. By holding at a temperature of 1 second to 3 hours at a temperature higher than 0.degree. C. and carrying out a thermal decomposition treatment, a transparent and homogeneous titanium oxide thin film with a uniform film thickness can be formed on the surface of the heat-resistant base material. The coating method for applying the coating liquid to the heat-resistant substrate is the dipping method, spray method, spinner method, printing method,
Any known method such as the brush printing method can be employed, but the dipping and pulling method is preferable when forming a titanium oxide thin film with a uniform thickness. Also, 300
A titanium oxide thin film can also be formed by spraying a coating liquid onto a heat-resistant substrate heated to a temperature of .degree. C. or higher and thermally decomposing it. In the present invention, an optical interference film can be obtained by forming a multilayer film by alternately forming a thin film of titanium oxide and a thin film of a metal oxide other than titanium oxide with a low refractive index, such as silicon oxide, to a predetermined thickness. . The silicon oxide thin film is made of organic silicon compounds containing organic alkoxysilanes and their derivatives such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, diethoxydiisopropoxysilane, dichlorodimethoxysilane, etc. Heat-resistant substrates or
It can be formed by coating a heat-resistant base material on which a titanium oxide thin film is formed and heating and baking it. For example, TiO ₂ /SiO ₂ /
TiO ₂ triple layer film, TiO ₂ /SiO ₂ /TiO ₂ /SiO ₂ /TiO ₂
By forming a five-layer film, a light-reflecting film can be obtained. The composition for forming a titanium oxide thin film of the present invention comprises an organic titanium compound A and an organic titanium compound polymer B.
It has the following characteristics by having a mixture with as the main component. (1) Excellent stability, especially moisture resistance. (2) Excellent film formability, especially interlayer adhesion with dissimilar metal oxide thin films. (3) A titanium oxide thin film with a high refractive index can be obtained. In the present invention, the adhesion of the organic titanium compound A to the substrate and the film formability of the organic titanium compound polymer B act synergistically to produce an optical interference film with a high refractive index and excellent interlayer adhesion. It is assumed that this will be obtained. The present invention is used to produce an optical interference film that is highly stable and has excellent film formability, especially interlayer adhesion with a dissimilar metal oxide thin film, and can obtain a homogeneous titanium oxide thin film with a high refractive index. The present invention provides a titanium oxide thin film-forming composition suitable for the following, and its industrial significance is extremely large. EXAMPLES Below, the present invention will be explained in more detail with reference to Examples. However, the scope of the present invention is not limited in any way by the following examples. Example 1 Synthesis of organic titanium compound A: Tetraisopropoxytitanium Ti (OiPr) ₄ :
42.6g was dissolved in 234g of ethanol, 30g of acetylacetone was added and reacted, and Ti(OiPr) _4-
An ethanol solution containing 4.6 g of an organic titanium compound A in which part of the OiPr group was substituted with an acetylacetone residue was prepared. (iPr represents an isopropyl group.) Synthesis of organic titanium compound polymer B: Tetraisopropoxytitanium・Ti (OiPr) ₄ :
Dissolve 56.8g in 350g of ethanol and stir with sewage.
3.2g was gradually added and polymerized. Then, while stirring this solution, 40 g of acetylacetone was added to prepare an ethanol solution containing 60.8 g of organotitanium compound polymer B with a degree of polymerization: n = 10 in which some of the -OiPr groups were substituted with acetylacetone residues. did. Preparation of titanium oxide thin film forming composition (coating solution): Mix 30 g of the ethanol solution of organic titanium compound A prepared above and 400 g of ethanol solution of organic titanium compound polymer B, and add pentoxide as a vitreous forming material. Add 0.4g of phosphorus/P ₂ O ₅ ,
A composition for forming a titanium oxide thin film was prepared in which the mixture concentration of organic titanium compound A and organic titanium compound polymer B in terms of TiO ₂ was 3.6 g% by weight. Manufacture of optical interference (reflection) film: Use the composition for forming a titanium oxide thin film prepared above as a coating solution, and use a well-washed 60 mm film as a base material in this coating solution.
×120mm ×1mm soda lime glass was immersed and pulled up, then placed in an electric furnace heated to a temperature of 500℃.
A titanium oxide thin film was formed on the substrate by heating and baking for 30 minutes. The formed titanium oxide thin film was a transparent thin film with a uniform thickness of 610 Å, and the refractive index at a wavelength of 540 nm was 2.2. Next, the _above titanium oxide was added to an organic solvent solution (Atron R NSi-500, main component silicate polymer, main solvent acetate ester, manufactured by Nippon Soda Co., Ltd.) containing an organosilicon compound with a concentration of 5.0% by weight in terms of SiO 2 . The substrate on which the thin film was formed was immersed, pulled up, and fired for 30 minutes in an electric furnace heated to a temperature of 500° C., thereby forming a silicon oxide thin film on the titanium oxide thin film formed above. The silicon oxide thin film formed has a thickness of
It was a uniform transparent thin film of 900 Å. Furthermore, on top of forming the silicon oxide thin film, a titanium oxide thin film, a silicon oxide thin film, and further a titanium oxide thin film are formed in the same manner as above,
A five-layer film of TiO ₂ /SiO ₂ /TiO ₂ /SiO ₂ /TiO ₂ was obtained. The total thickness of the five-layer film obtained was 3630 Å,
The emission rate of light with a wavelength of 540 nm was 91%. Examples 2 to 14 In Example 1, the type and reaction molar ratio of titanium alkoxide, carboxylic acid and/or chelating agent were changed, and the amount of water during synthesis of thian alkoxide polymer was changed to produce organic titanium compound A. , organic titanium compound polymer B and organic titanium compound polymer B in various ratios were prepared. The prepared composition for forming a titanium oxide thin film was applied to the same soda lime glass substrate as in Example 1, and then treated in the same manner as in Example 1 to form a titanium oxide thin film and the refractive index was measured. Further, the same treatment as in Example 1 was carried out to laminate a silicon oxide thin film and a titanium oxide thin film to produce an optical interference film. Types of titanium alkoxide, carboxylic acid, and chelating agent used and their reaction molar ratios, degree of polymerization of organic titanium compound B, quantitative ratio (parts by weight) of organic titanium compound A and organic titanium compound polymer B, type of organic solvent Table 1 shows the concentration of the mixture of organic titanium compound A and organic titanium compound polymer B in terms of TiO ₂ . Table 1 shows the thin film properties of the titanium oxide thin film and optical interference film produced using this titanium oxide thin film forming composition. In addition, as a comparison, the physical properties of thin films when using a coating liquid containing only organic titanium compound A and when using a coating liquid containing only organic titanium compound polymer B are shown in Table 1 together with Examples. In Table 1, the abbreviations for iPr; isopropyl group nBu; normal butyl group AA; acetylacetone MAA; methyl acetoacetate EAA; ethyl acetoacetate LA; lactic acid iSt; stearic acid OG; octylene glycol TEA; triethanolamine are used. In Table 1, the indications of film formability mean the following. ◎ A uniform multilayer film was obtained. ○ A multilayer film was obtained, but slight unevenness was observed. × Peeling occurred in the third layer, and a multilayer film could not be obtained.

【table】

【table】

Claims (1)

[Claims] 1 General formula: Ti(OR) ₄ (herein, R represents the same kind of monovalent hydrocarbon group having 1 to 18 carbon atoms) of the alkoxy group of titanium alkoxides A residue of a carboxylic acid represented by the general formula: HOCOR': -OCOR' (wherein, R represents a monovalent hydrocarbon group having 1 to 18 carbon atoms) and the general formula: HX 5 to 50 parts by weight of an organic titanium compound A substituted with one or more selected from the group -X: a residue of an organic compound capable of forming a chelate ring with titanium represented by the formula: Ti( OR) ₄ (Here, R represents the same type of monovalent hydrocarbon group having 1 to 18 carbon atoms.) Titanium alkoxide polymer obtained by hydropolymerizing titanium alkoxides of the same type or type represented by Substituent: Part or all of -OR General formula: Residue of carboxylic acid represented by HOCOR': -OCOR' (Here, R' represents a monovalent hydrocarbon group having 1 to 18 carbon atoms. ) and Residue of an organic compound capable of forming a chelate ring with titanium represented by general formula: HX: Organic titanium compound polymer B substituted with one or more selected from the group -X: 95 to 50 1. A composition for forming a titanium oxide thin film, comprising an organic solvent solution containing a mixture of parts by weight. 2 Organic compounds capable of forming a chelate ring with titanium represented by the general formula HX include β-diketones, α
- or β-keto acids, lower alkyl esters of keto acids, oxyacids, lower alkyl esters of oxyacids, diols, and amino alcohols. The composition for forming a titanium oxide thin film according to item 1. 3. The composition for forming a titanium oxide thin film according to claim 1, which contains one or more glass forming agents selected from the group of phosphorus compounds, boron compounds, arsenic compounds, and antimony compounds. 4 The concentration of the mixture of organic titanium compound A and organic titanium compound polymer B in terms of TiO ₂ is 1 to
20% by weight of the composition for forming a titanium oxide thin film according to claim 1.