JP2004148812A - Thin film forming article and its manufacture method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film forming article which can decrease the occurrence of appearance irregularities such as an interference unevenness, streak and the like on a silicone resin thin film whose thickness is uneven at dually coated sections. <P>SOLUTION: The thin film forming article is obtained, by uniformly dispersing the fine particles having a refractive index of n or higher in the transparent silicone resin having a refractive index of n or lower, on the surface of a transparent layer having a refractive of n which is provided on the surface of a transparent substrate or the substrate having a refractive index of n. The article is manufactured so that the thin film whose refractive index has been prepared to be substantially equivalent to n can be formed. Thereby, even if the uneven thickness of the thin film exists, the occurrence of the interference unevenness can be decreased. <P>COPYRIGHT: (C)2004,JPO

Description

  TECHNICAL FIELD The present invention relates to a thin film-formed product in which a thin film is formed on a surface of a transparent substrate or a surface of a transparent layer provided on the surface of the substrate, and a method for producing the same.

  Forming a silicone resin film by applying and curing a coating material containing organosiloxane as a main component on the surface of a transparent substrate such as a glass substrate or the surface of a substrate provided with a transparent layer on the surface. Has been conventionally performed (for example, see Patent Document 1). Since the surface of this silicone resin film shows a glassy property, organic substances repelling water attached to the surface of the base material (thing attached to the surface of the silicone resin film or contained in the surface of the silicone resin thin film) It is easy to wash and remove by rainwater, and there is also an improvement in hydrophilicity (water wettability) such that the surface is easily wetted (familiar) with water, and an effect of realizing a low-contamination surface can be expected.

However, this silicone resin thin film is generally a transparent base material or a transparent coating film forming element having a smaller refractive index than the transparent layer, and has a thickness range of several tens nm to several hundred nm. However, there is a problem in that a coating film that absorbs electromagnetic waves having a wavelength in the visible light range and has an uneven thickness may cause uneven interference with the silicone resin thin film according to the thickness. Was. In particular, a layered portion or the like generated by brush coating or bar coating has a problem in that the film thickness tends to be uneven, and streak unevenness is likely to occur in this portion.
JP-A-10-146251

  The present invention has been made in view of the above points, and has a thin film formation capable of reducing appearance irregularities such as interference unevenness and streaks in a silicone resin thin film having an uneven film thickness such as an overcoated portion. It is an object of the present invention to provide a product and a method for manufacturing the same.

  The thin film-formed product according to claim 1 of the present invention is a transparent silicone having a refractive index smaller than n on the surface of a transparent substrate having a refractive index of n or on the surface of a transparent layer having a refractive index of n provided on the substrate. Characterized in that a thin film obtained by uniformly dispersing fine particles having a refractive index larger than n in a resin and having a refractive index adjusted as a film substantially equal to n is formed. It is.

  According to a second aspect of the present invention, in the first aspect, the fine particles having a refractive index larger than n are a metal oxide sol.

  According to a third aspect of the present invention, in the first or second aspect, the thickness of the thin film adjusted to have a refractive index substantially equal to n is 20 nm to 1000 nm. .

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the fine particles having a refractive index larger than n have a particle diameter in a range of 5 nm to 200 nm.

  The method for producing a thin film-formed product according to claim 5 of the present invention has a refractive index smaller than n on the surface of a transparent substrate having a refractive index of n or on the surface of a transparent layer having a refractive index of n provided on the substrate. A coating material obtained by uniformly dispersing fine particles having a refractive index larger than n in a transparent silicone resin is applied to form a thin film adjusted so that the refractive index of the film is substantially equal to n. It is characterized by the following.

  According to the invention of claim 1 relating to a thin film formed product, it is possible to reduce the occurrence of interference unevenness even if the thin film has uneven film thickness, and in particular, it is possible to reduce the overlap generated by brush coating or bar coating. Even if a large unevenness in film thickness occurs in a painted portion or the like, it is possible to reduce occurrence of unevenness in stripes due to interference in this portion.

  According to the second aspect of the present invention, the metal oxide sol has good compatibility with the silicone resin and dispersion stability, and has a high effect of uniformly dispersing the fine particles and improving the refractive index of the thin film. Can be done.

  According to the third aspect of the invention, the effect of reducing the interference unevenness by adjusting the refractive index of the thin film can be effectively obtained.

  According to the invention of claim 4, it is possible to obtain good stability of the uniform dispersion of the fine particles and to prevent the particle diameter from becoming larger than the thickness of the thin film and deteriorating the film strength. is there.

  According to the invention of claim 5, which relates to a method of manufacturing a thin film-formed product, it is possible to reduce the occurrence of uneven interference even if the thin film has uneven film thickness. Even if a large unevenness in film thickness occurs in the overcoated portion or the like, it is possible to reduce the occurrence of line unevenness due to interference in this portion.

  Hereinafter, the best mode for carrying out the present invention will be described.

In the present invention, a silicone resin-based inorganic paint used to form a thin film on the surface of the transparent substrate or the surface of the transparent layer,
Component (A): General formula Si (OR) ₄ (1) (where R is a monovalent hydrocarbon group)
Those containing a hydrolyzate and / or a partial hydrolyzate of an organosilicon alkoxide represented by the following formula (1) are preferable.

  The hydrolyzate and partial hydrolyzate of the alkoxide of the above-mentioned component (A) are used as a binder resin and a film-forming component, and are added to the coating thin film to impart surface hydrophilicity (water wettability) to prevent the thin film. It is a component that provides cloudiness, antifouling properties by rainwater washing, and the like. It is preferable that the organosilicon alkoxide is tetrafunctional as in the above formula (1) because of its high hydrophilicity, but it is not limited to this, and it is not limited thereto, and it may be trifunctional or bifunctional. Good. The form of the hydrolyzate and partial hydrolyzate of the alkoxide is not particularly limited, and may be, for example, a solution or a dispersion.

  R in the formula of the component (A) is not particularly limited as long as it is a monovalent hydrocarbon group, and is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, for example, a methyl group, an ethyl group, Examples thereof include alkyl groups such as a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and an octyl group. Among the alkyl groups contained in the alkoxy group, those having 3 or more carbon atoms may be linear such as an n-propyl group, an n-butyl group, or an isopropyl group, It may have a branch such as an isobutyl group or a t-butyl group. The amount of water present during the (partial) hydrolysis of the alkoxide is not particularly limited. In addition, the catalyst used as required when the alkoxide is partially hydrolyzed is not particularly limited, but an acidic catalyst is preferable from the viewpoint of shortening the time required for the production process. Examples of the acidic catalyst include, but are not limited to, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluenesulfonic acid, and oxalic acid. Organic acids; inorganic acids such as hydrochloric acid, nitric acid, and halogenated silane; acidic sol-like fillers such as acidic colloidal silica and titania sol; and the like, and one or more of these can be used. The (partial) hydrolysis of the alkoxide may be performed, if necessary, by heating at a heating temperature of, for example, 40 to 100 ° C.

  The (partial) hydrolysis of the alkoxide may be carried out, if necessary, by diluting with an appropriate solvent. Such a diluting solvent is not particularly limited. For example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether such as acetate And ethylene glycol derivatives; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol. One or more selected from the group consisting of these can be used. In combination with these hydrophilic organic solvents, one or more of toluene, xylene, hexane, heptane, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can be used.

  The weight average molecular weight of the partial hydrolyzate of the alkoxide used in the present invention is not particularly limited, but is preferably in the range of 500 to 8000. This is because if it is less than 500, the hydrolyzate becomes unstable, and if it exceeds 8000, there are disadvantages such as the coating thin film not being able to maintain sufficient hardness.

  Further, it is preferable to add one or more silica components (component (B)) to the silicone resin component used in the present invention, if necessary, from the viewpoint of improving the hardness, the stability, and the film forming property of the silicone resin thin film. . The component (B) is not particularly limited, and a known component can be used. The form of the silica is not particularly limited, and may be, for example, a powder form or a sol form (colloidal silica). The colloidal silica is not particularly limited, but for example, water-dispersible or non-aqueous organic solvent-dispersible colloidal silica such as alcohol can be used. Generally, such colloidal silica contains 20 to 50% by mass of silica as a solid content, and the amount of silica can be determined from this value. When water-dispersible colloidal silica is used, water present in the colloidal silica as a substance other than solids can be used for the (partial) hydrolysis of the alkoxide. Added to water usage. The water-dispersible colloidal silica is usually made of water glass, but can be easily obtained as a commercial product.

  The organic solvent-dispersible colloidal silica can be easily prepared by replacing water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersible colloidal silica can be easily obtained as a commercial product similarly to the water-dispersible colloidal silica. In the organic solvent dispersible colloidal silica, the type of the organic solvent in which the colloidal silica is dispersed is not particularly limited. For example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene Ethylene glycol derivatives such as glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol; and one selected from the group consisting of these. Alternatively, two or more kinds can be used. In combination with these hydrophilic organic solvents, one or more of toluene, xylene, hexane, heptane, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can be used.

  The blending amount of the silica as the component (B) is not particularly limited. For example, the mass ratio (B / (A + B)) of the total mass of the components (A) and (B) in terms of solid content is The ratio is preferably 0.60 to 0.95 in terms of solid content, more preferably 0.65 to 0.9. If it is less than 0.6, the effect of the added silica filler tends to be hardly obtained, and it becomes difficult to obtain initial hydrophilicity. On the other hand, when the ratio is 0.95 or more, the film-forming property of the coating film is deteriorated, and the abrasion resistance is deteriorated or the coating film is whitened. The method for uniformly dispersing the silica filler in the dispersion medium is not particularly limited, and for example, various ordinary dispersion methods using a homogenizer, a disper, a paint shaker, a bead mill, or the like can be used.

  The silica may be in any form as long as it is dispersible, such as powder, fine particle powder, and solution-dispersed sol particles. Proceeds in time and is very convenient to use. The dispersion medium to be used is not particularly limited as long as the fine particles can be uniformly dispersed, and any of an aqueous solvent and a non-aqueous solvent can be used. The aqueous solvent is not particularly limited. For example, in addition to water alone, hydrophilic organic solvents such as lower fatty acid alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monoethylene A mixed solvent of at least one of ethylene glycol derivatives such as butyl ether and ethylene glycol monobutyl ether acetate; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol can be used. Among the above aqueous solvents, a water-methanol mixed solvent is preferable in terms of dispersion stability of the fine particles and drying of the dispersion solvent after coating. Furthermore, by using an aqueous sol, the sol can also function as an acidic catalyst at the time of hydrolysis of the alkoxide. The non-aqueous solvent is not particularly limited, and for example, at least one selected from the group consisting of the above-mentioned hydrophilic organic solvents and hydrophobic organic solvents such as toluene and xylene can be used. Among these non-aqueous solvents, methanol is preferable in terms of dispersion stability and drying property of the dispersion medium after coating.

  Assuming that the refractive index of a transparent substrate or a transparent film such as glass is n, the refractive index of the above silicone resin is generally smaller than the refractive index n of a transparent substrate or a transparent film such as glass. In the present invention, fine particles (component (C)) having a refractive index larger than the refractive index n are uniformly dispersed and mixed in the silicone resin as the transparent thin film forming element.

The fine particles of the component (C) are not particularly limited, and known particles can be used. For example, ZrO ₂ , SnO ₂ , PZT, Y ₂ O ₃ , TiO ₂ , In ₂ O ₃ , and ITO , Α-Al ₂ O ₃ , HAP, Fe ₂ O ₃ , Fe ₃ O ₄ , ZnO, BaTiO ₃ , MgF ₂ , TiN, Sb ₂ O ₃ , CaF ₂ , CeO ₂ , CeF ₃ , Na ₃ AlF ₆ , La ₂ O ₃ , LaF ₃ , PbF ₂ , NdF ₃ , Pr ₅ O ₁₁ , SiO, ThO ₂ , ThF ₄ , ZnS and the like can be mentioned, and one or more of these can be used. Among these, a metal oxide sol is particularly preferred from the viewpoint of good compatibility with the silicone resin and dispersion stability.

  The fine particles of the component (C) may be in any form as long as they can be dispersed, such as powder, fine particle powder, and solution-dispersed sol particles. Progresses in a shorter time and is more convenient in use. The dispersion medium used for dispersing the fine particles is not particularly limited as long as it can uniformly disperse the fine particles of the component (C), and any aqueous or non-aqueous solvent can be used. The aqueous solvent is not particularly limited. For example, in addition to water alone, hydrophilic organic solvents such as lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monoethylene A mixed solvent of at least one of ethylene glycol derivatives such as butyl ether and ethylene glycol monobutyl ether acetate; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol can be used. Among the above aqueous solvents, a mixed solvent of water and ethanol is preferred in terms of dispersion stability of the fine particles and drying of the dispersion solvent after coating. Furthermore, by using an aqueous sol, it can also serve as an acidic catalyst at the time of hydrolysis of an alkoxide. The non-aqueous solvent is not particularly limited, and includes, for example, the hydrophilic organic solvent and a hydrophobic organic solvent such as toluene, xylene, hexane, heptane, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methyl ethyl ketoxime. At least one selected from the group can be used. Among these non-aqueous solvents, methanol is preferred in terms of dispersion stability and drying property of the dispersion medium after coating.

  The amount of the fine particles of the component (C) is such that the refractive index of the thin film formed on the surface of the transparent substrate or the surface of the transparent layer is substantially equal to the refractive index n of the transparent substrate or the transparent layer. There is no particular limitation as long as it can be adjusted so that, for example, the mass ratio (C / (A + B + C)) to the total mass of the components (A), (B) and (C) in terms of solid content is 0.1. It is preferably set to be in the range of 01 to 0.9, more preferably in the range of 0.1 to 0.5. If the mixing ratio of the fine particles is less than 0.01, the effect of improving the refractive index by adding the fine particles tends to be insufficient. Further, when the mixing ratio of the fine particles is 0.9 or more, the film-forming property of the coating film is deteriorated, and the abrasion resistance is deteriorated or the coating film is whitened. The method for dispersing the fine particles in the dispersion medium is not particularly limited, and for example, various ordinary methods using a homogenizer, a disper, a paint shaker, a bead mill, or the like can be used.

  As described above, a coating material prepared by blending fine particles having a refractive index greater than n with a silicone resin that is a thin film forming element having a refractive index smaller than n is applied to the surface of a transparent substrate having a refractive index n. Alternatively, a thin film-formed product can be obtained by applying the composition on the surface of a transparent layer having a refractive index of n provided on a base material, and drying and curing to form a thin film. The thin film formed by uniformly dispersing the fine particles in the silicone resin has a refractive index substantially equal to the refractive index n of the transparent substrate or the transparent layer, and has a nonuniform thickness. This can reduce the occurrence of interference unevenness, even if there is a large unevenness in film thickness, especially in the overcoating area that occurs during brush coating or bar coating. The occurrence can be reduced. Here, in the present invention, it is not particularly limited that the refractive index of the thin film is substantially equal to n, but it is preferable that the refractive index of the thin film is in a range of n ± 0.1. More preferably, the range is ± 0.05. When the refractive index of the thin film is in the range of n ± 0.05, the interference pattern is of a degree that cannot be confirmed by human eyes, and when the refractive index of the thin film is in the range of n ± 0.1, the interference pattern is reduced. You can check it, but you won't be bothered.

  Here, the thickness of the thin film formed on the surface of the transparent substrate or the transparent layer is related to the intensity of the interference. If the thickness is less than 20 nm, the thickness of the interference in the visible light region is reduced. When the influence is weakened, and when the film thickness exceeds 1000 nm, uneven interference hardly occurs. Therefore, the present invention can be applied to the case where the thickness of the thin film is in the range of 20 nm to 1000 nm, and a particularly large effect can be obtained.

  When the particle diameter of the fine particles of the component (C) is 5 nm or less, the stability of uniform dispersion of the fine particles in forming a thin film is poor, and aggregation may easily occur. When the particle diameter is 200 nm or more, the particle diameter may be larger than the thickness of the thin film, and the film strength of the thin film may be deteriorated. For this reason, the particle diameter of the fine particles is preferably in the range of 5 nm to 200 nm.

  The method of applying the above coating material is not particularly limited, and examples thereof include brush coating, spray coating, dipping (also called dipping and dip coating), roll coating, flow coating, curtain coating, knife coating, spin coating, and the like. Various commonly used coating methods such as bar coating can be selected. The curing method may be a known method, and is not particularly limited. The temperature at the time of curing is not particularly limited, either, and a wide temperature range from room temperature to heating can be taken according to the desired performance of the cured thin film and the use of a curing catalyst.

  Hereinafter, the present invention will be described specifically with reference to examples. In Examples, unless otherwise specified, all “parts” represent “parts by mass” and all “%” represent “% by mass”. In addition, this invention is not limited to a following example.

(Example 1)
356 parts of isopropyl alcohol was added to 208 parts of tetraethoxysilane, and 180 parts of water and 18 parts of 0.01 N hydrochloric acid were further mixed and mixed well using a disper to obtain a 4-functional silicone resin coating solution. The refractive index of the polymerized and cured product of this tetrafunctional silicone resin is 1.43. Next, an antimony oxide sol (trade name “AMT-130S”, manufactured by Nissan Chemical Industries, Ltd .: Sb ₂ O ₅ ; refractive index: 1.66, particle diameter: about 30 nm) was formed into a thin film on the tetrafunctional silicone resin coating solution. Is added to the mixture so that the refractive index of the thin film becomes 1.54, and after a polymerization reaction at 60 ° C. for 10 hours, the mixture is diluted with IPA (isopropyl alcohol) so that the total solid content becomes 1%. And an inorganic coating material was prepared.

  Then, after the inorganic coating material is dropped on the surface of the glass substrate (refractive index 1.54), spin coating is performed while adjusting the rotation speed so that the film thickness after drying becomes about 100 nm, Further, by baking at 100 ° C. for 10 minutes, a thin film was obtained.

(Example 2)
In Example 1, except that the inorganic coating material was prepared so that the refractive index of the thin film when the thin film was formed was 1.49, and the inorganic coating material was applied so that the film thickness after drying became 60 nm. In the same manner as in Example 1, a thin film was obtained.

(Example 3)
A thin film was obtained in the same manner as in Example 1 except that the inorganic coating material was applied so that the film thickness after drying was 800 nm.

(Example 4)
A thin film was obtained in the same manner as in Example 1 except that antimony oxide having a particle diameter of 60 nm was used and an inorganic coating material was applied so that the film thickness after drying became 120 nm.

(Example 5)
A thin film was obtained in the same manner as in Example 1, except that the inorganic coating material was applied so that the film thickness after drying became 1200 nm.

(Example 6)
A thin film was obtained in the same manner as in Example 1 except that antimony oxide having a particle diameter of 80 nm was used and an inorganic coating material was applied so that the film thickness after drying was 30 nm.

(Example 7)
In Example 1, instead of the antimony oxide sol, niobium oxide sol (“Optreak 17” manufactured by Catalysts & Chemicals, Inc .: Nb ₂ O ₅ ; refractive index: 2.1, particle diameter: about 10 nm) was used. An inorganic coating material was prepared in the same manner as in Example 1, except that the zinc sulfide sol was added to the tetrafunctional silicone resin coating solution so as to obtain 1.54. A thin film was obtained in the same manner as in Example 1.

(Comparative Example 1)
In Example 1, an inorganic coating material was prepared without adding antimony oxide sol so that the thin film had a refractive index of 1.43 when the thin film was formed. A thin film was obtained in the same manner as described above.

(Comparative Example 2)
In Example 1, in place of the antimony oxide sol, titanium oxide sol (Catalysts & Chemicals Industries Co., Ltd. "Quinn Titanic": TiO _2; refractive index 2.27, particle size about 10 nm) using a thin film refractive index of 1.68 An inorganic coating material was prepared in the same manner as in Example 1 except that this titanium oxide sol was added to the tetrafunctional silicone resin coating solution so that To obtain a thin film.

[Evaluation of coating film performance]
(With or without interference)
The thin film immediately after the film formation was visually evaluated by holding it over white light and paying particular attention to whether an iridescent interference color was generated.

(Appearance evaluation)
The thin film immediately after film formation was visually evaluated, particularly focusing on the presence or absence of efflorescence, the repellency of the coating liquid, and the gloss.

(Contact angle of water at the beginning of thin film)
Immediately after film formation, 0.2 cc of distilled water was dropped on the surface of the thin film, and the measurement was performed by observing with a magnifying camera.

  As can be seen from Table 1, in Examples 1 to 4 and 7, no interference pattern was generated, and the appearance was good without whitening, repelling, gloss, cracks, and maintaining transparency. Further, the contact angle of water was as good as 10 degrees or less from the initial stage of film formation. In Examples 5 and 6, interference was suppressed as compared with Comparative Example 1, and the results were good. However, in Example 5, in which the film thickness was as thick as 1200 nm, cracks occurred when the thin film was formed, and the film thickness was sufficiently larger than the film thickness. In Example 6 in which fine particles having a particle diameter were added, the surface was shiny when a thin film was formed. On the other hand, in Comparative Example 1 in which the refractive index of the thin film was low, the appearance could be formed into a transparent coating film without cracks and gloss, but when looking at the reflected light of white light, the interference of red and yellow depending on the unevenness of the film thickness was observed. There were stripes. Further, in Comparative Example 2 in which the refractive index of the thin film was high, red and white interference fringes were formed according to the unevenness of the film thickness.

  By the above, the thin film adjusted to the same refractive index as the refractive index of the substrate, even when the reflected light of white light is observed, no rainbow pattern is seen, and a low interference color coating film is formed. It is confirmed that can be done.

Claims (5)

  Fine particles having a refractive index greater than n are uniformly dispersed in a transparent silicone resin having a refractive index smaller than n on the surface of a transparent substrate having a refractive index of n or the surface of a transparent layer having a refractive index of n provided on the substrate. A thin film formed by forming a thin film adjusted so that the refractive index as a film is substantially equal to n, which is obtained by dispersing the thin film.   2. The thin film-formed article according to claim 1, wherein the fine particles having a refractive index larger than n are a metal oxide sol.   The thin film-formed product according to claim 1, wherein a thickness of the thin film adjusted so that a refractive index is substantially equal to n is 20 nm to 1000 nm.   The thin film-formed article according to any one of claims 1 to 3, wherein the fine particles having a refractive index larger than n have a particle diameter in a range of 5 nm to 200 nm.   Fine particles having a refractive index greater than n are uniformly dispersed in a transparent silicone resin having a refractive index smaller than n on the surface of a transparent substrate having a refractive index of n or the surface of a transparent layer having a refractive index of n provided on the substrate. A method for producing a thin film-formed product, comprising: applying a coating material obtained by dispersing a thin film to form a thin film adjusted so that the refractive index of the film is substantially equal to n.