JP2001207120A - Method for producing highly light-transmitting film and coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a highly light-transmitting film having high surface hardness and not deteriorating the performance even with the passage of time by the use of a fluorine-based material. SOLUTION: This method for producing the highly light-transmitting film is characterized by coating a substrate with a silicate compound treated with a silane coupling agent having a fluorochain and then curing the coating. Another objective coating composition comprises (A) a silicate compound treated with the silane coupling agent having the fluorochain, (B) a photocuring material, (C) a photoinitiator, and (D) a silicate curing catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a highly translucent film, a coating composition, and an article provided with the film obtained therefrom.

[0002]

2. Description of the Related Art In recent years, it has been studied to provide a so-called high light-transmitting film having low light reflectivity and high light transmittance as a filter for increasing the luminous intensity in a liquid crystal display of a notebook personal computer.

It is known that such a film having a high light-transmitting property is obtained from a low refractive index material such as a fluorine resin such as polyvinylidene fluoride. However, the film obtained from this fluororesin has excellent light transmittance, but has a problem that the film hardness is not sufficient.

On the other hand, fluorine silicate as a paint additive for improving stain resistance is disclosed in WO96 / 26254.
Is disclosed. When a film is formed using this fluorine silicate, the film initially has a high light transmittance, but the hydrolysis proceeds with time, so the fluorine-containing group is eliminated, and the light transmittance decreases. There is a problem that it will.

It is known that a film having a high translucency can be formed by combining materials having different refractive indices on the order of μm. For example, by combining a layer with a refractive index of 1.37 with one surface of a layer with a refractive index of 1.56 (light transmittance of 90.5%), the total light transmittance is improved to 92%. Here, when a layer having a refractive index of 1.5, which is an intermediate between the two layers, is provided between these two layers, the light transmittance is further improved to 92.5%, and the layer having a refractive index of 1.37 itself is improved. Exceeds translucency. Further, if a film is formed so that the refractive index changes continuously from the material to the air interface, it is considered that a film having a lower refractive index can be formed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a highly light-transmitting film using a fluorine-based material, which has a high surface hardness and whose performance does not decrease over time. is there.

[0007]

The method for producing a highly translucent film of the present invention is characterized in that a silicate compound treated with a silane coupling agent having a fluorine chain is applied to a substrate and cured.

Further, another method for producing a highly translucent film of the present invention comprises the steps of: A) a silicate compound treated with a silane coupling agent having a fluorine chain; B) a photocurable material;
A coating composition containing a photoinitiator and D) a silicate curing catalyst is applied to a substrate and cured. Here, the above-mentioned curing can be performed by light irradiation and then by heat, and B) the refractive index of the photo-curable material is located between A) the refractive index of the silicate compound and the refractive index of the substrate. It may be. Further, D) the silicate curing catalyst may have photolatent or thermal latency.

Further, the coating composition of the present invention comprises:
A) a silicate compound treated with a silane coupling agent having a fluorine chain, B) a photocurable material, C) a photoinitiator,
And D) a silicate curing catalyst.

[0010] Further, the article of the present invention is provided with a highly translucent film obtained by the above manufacturing method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The first method for producing a highly light-transmitting film of the present invention comprises applying a silicate compound treated with a silane coupling agent having a fluorine chain to a substrate and curing the substrate.

The silane coupling agent having a fluorine chain is used for introducing a fluorine chain into a silicate compound, and has a fluorine chain and a trialkoxysilyl group. Such is of the formula CF ₃
(CF ₂ ) _l (CH ₂ ) _m Si (OR) _n R _3-n (l is 0 to
An integer of 3, m is an integer of 0 to 10, n is an integer of 1 to 3, and R is an alkyl group having 1 to 5 carbon atoms. For example, CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ For example, commercially available silane coupling agents can be used. Here, if l is larger than 3, the state may be incompatible with the silicate compound, and the treatment may not proceed well, and the hardness of the obtained film may be reduced.

On the other hand, the silicate compound to be treated with the silane coupling agent having a fluorine chain is Si
It is a tetraalkoxysilane represented by (OR) ₄ (R is an alkyl group having 1 to 4 carbon atoms) or a hydrolytic condensate thereof. When the carbon number of R is more than 4, the curing speed decreases. Specific compounds of tetraalkoxysilane include tetramethylsilane, tetraethylsilane, tetrapropylsilane, and tetrabutylsilane. Hydrolysis condensates of these tetraalkoxysilanes are commercially available. For example, M
KC silicate 51, 56 and ES from Colcoat
40 and the like.

The above treatment of the silicate compound with the silane coupling agent having a fluorine chain can be carried out by subjecting the silane coupling agent and the silicate compound to a condensation reaction under acidic conditions. The reaction conditions such as the reaction temperature can be set by those skilled in the art according to the materials used and the like.

The silicate compound thus treated with the silane coupling agent having a fluorine chain has a refractive index smaller than that of the original silicate compound due to the introduction of the fluorine chain.

In the first method for producing a highly translucent film of the present invention, a silicate compound treated with the silane coupling agent having a fluorine chain is applied to a substrate and cured. In this coating, the silicate compound treated with the silane coupling agent having a fluorine chain is preferably diluted with a solvent for facilitating coating, and a curing catalyst is preferably co-present for accelerating curing. The solvent is not particularly limited as long as it dissolves the previously treated silicate compound, but is preferably an alcohol from the viewpoint of the stability of the coating composition, and is the same type as the alkoxy group of the silicate compound. It is more preferable to use alcohol.

The amount of the solvent to be used can be appropriately adjusted so that the film thickness becomes 3 to 30 μm, for example, 20 to 100 parts by weight of the above treated silicate compound.
It can be 1000 parts by weight. The curing catalyst is preferably one that promotes a condensation reaction of a silicate compound, and examples of such a curing catalyst include an acid compound. Of these, Lewis acid compounds are preferred. Examples of Lewis acid compounds include metal alkoxides such as acetoacetoxyaluminum and metal chelates. The amount of the curing catalyst can be appropriately determined, and is, for example, 0.1 to 10 parts by weight based on 100 parts by weight of the silicate compound previously treated.

The above treated silicate compound is applied to a substrate by various methods, for example, using a bar coater, a doctor blade, a spin coater, a flow coater, or a roll coater. This base material needs to be provided with a high light-transmitting film, for example, PET, polycarbonate, or the like.
And the like. The coating amount can be adjusted so that the finally obtained film thickness is 3 to 30 μm. If the film thickness is less than 1 μm, light interference will occur in the non-uniform part, and if it exceeds 30 μm, it will be difficult to apply the coating with one coat.

The silicate compound thus treated with the silane coupling agent having a fluorine chain applied to the substrate undergoes a curing reaction by heating. The curing conditions vary depending on the type of the treated silicate compound and the material of the base material used, but generally, a high translucent film is obtained by heating at 100 to 150 ° C. for 5 to 60 minutes. Can be.

The second method for producing a highly translucent film according to the present invention comprises:
A) a silicate compound treated with a silane coupling agent having a fluorine chain, B) a photocurable material, C) a photoinitiator,
And D) a coating composition containing a silicate curing catalyst is applied to a substrate and cured. Further, the coating composition of the present invention contains A) a silicate compound treated with a silane coupling agent having a fluorine chain, B) a photocurable material, C) a photoinitiator, and D) a silicate curing catalyst. I have.

Here, the silicate compound treated with the silane coupling agent having a fluorine chain in the above A) is the same as that described in the first method for producing a highly translucent film.

Next, the photocurable material B) will be described. This material has a photopolymerizable functional group in the molecule, and preferably has two or more photopolymerizable functional groups. As such, for example, polyhydroxy compounds such as ethylene glycol, tetraethylene glycol, neopentyl glycol, propylene glycol, 1,2-butanediol, trimethylolpropane, pentaerythritol, and tripentaerythritol with acrylic acid and methacrylic acid Esters with unsaturated carboxylic acids such as, itaconic acid and maleic acid; epichlorohydrin to trimethylolpropane glycidyl ether, pentaerythritol polyglycidyl ether, propylene glycol diglycidyl ether, 2,2-bis (4-hydroxyphenyl) -propane A reaction product; an epoxide such as diglycidyl ester of phthalic acid, which is subjected to an addition reaction of the above unsaturated carboxylic acid; hexamethylene diisocyanate, 2,4- Li diisocyanate, isophorone diisocyanate, 4,4'-methylenebis (phenyl isocyanate) the polyfunctional isocyanate compound and 2-hydroxyethyl acrylate or the like,
Compounds such as polyurethane acrylates and polyurethane methacrylates synthesized from an acrylate or methacrylate having a hydroxyl group such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, or 2-hydroxypropyl methacrylate and the above polyhydroxy compound; And an acrylic resin having a (meth) acryloyl group as a pendant group. These can be selected according to the physical properties required for the obtained film. For example, when the film requires hardness, a polyfunctional one can be used. Further, depending on the type of the silicate compound of A), the compatibility with the photocurable material may be poor. In this case, the compatibility is adjusted by partially modifying the photocurable material with a silicate. Can be.

Further, by setting the refractive index of the photocurable material between the refractive index of the silicate compound and the refractive index of the substrate on which the coating composition is applied, the light transmittance of the obtained film is improved. Can be enhanced. Examples of the photoinitiator C) include benzyldimethylketal. These are generally commercially available, and the above compound is sold, for example, by Ciba-Geigy as Irgacure 651.

On the other hand, as the silicate curing catalyst D), those having photo-latent or thermal-latent properties can be used in addition to those described in the first method for producing a highly translucent film. The use of a material having such a potential can increase the stability of the coating composition and facilitate the handling. Those having the above-mentioned photolatent include S.A. Peter Pappas
"UV Curing: Science and
Technology "; Klingert et al., "Comments Inorg. Chem."
(Pages 109 to 138, No. 3, Vol. 7, 19)
And other publications such as Masahiro Kadooka et al., "New UV-EB Effect Technology and Application Development-New Photocatalyst-" (1st edition (version), published by Radotech Kenkyukai, pages 69-86, 1997). , But is not limited thereto. In addition to the above,
Those selected from 2,4,6-substituted-1,3,5-triazine compounds, onium compounds and metal arene complexes can also be used. On the other hand, a cation generator such as a benzylammonium or sulfonium salt can be given as one having the above-mentioned heat potential.

The above A) in the above coating composition
The content of the photocurable material of B) is 10 to 1900 parts by weight based on 100 parts by weight of the silicate compound treated with the silane coupling agent having a fluorine chain of A).
It is preferred that the photoinitiator of C) is 1 to 30 parts by weight and the silicate curing catalyst of D) is 1 to 10 parts by weight. If the photocurable material of B) is less than 10 parts by weight or exceeds 1900 parts by weight, high light transmittance cannot be obtained. When the amount of the photoinitiator C) is less than 1 part by weight, a film having sufficient strength cannot be obtained, and when the amount exceeds 10 parts by weight, the effect corresponding thereto cannot be obtained. Further, the silicate curing catalyst of D) contains 1
When the amount is less than 10 parts by weight, a film having sufficient strength cannot be obtained by heat curing in a short time, and when the amount exceeds 10 parts by weight, the water resistance of the film is deteriorated.

The coating composition used in the method for producing a highly translucent film of the present invention is a composition in which the above components are dissolved in a solvent. As the solvent, those described in the first method for manufacturing a high light-transmitting film can be used. Here, the solid content concentration of the coating composition can be arbitrarily set, for example, 10 to 70% by weight.

In the second method for producing a highly translucent film of the present invention, the above coating composition is applied to a substrate. Here, the base material and the coating are based on the contents described in the first method for manufacturing a highly translucent film.

The coating composition applied to the substrate is then dried. The solvent is distilled off by this drying, and an uncured film is obtained. The drying is preferably performed so as not to cure the film. The conditions vary depending on the type and content of the solvent used, but can be, for example, 60 to 120 ° C. for 5 to 30 minutes. When a heat latent catalyst is used, it is necessary to perform drying at a temperature lower than the temperature at which the catalytic function is exhibited.

The thus-obtained uncured film is then cured. This curing is first performed by light irradiation and then by heat. The light irradiation is performed at high speed U
The irradiation can be performed by irradiating a light irradiating device such as a V irradiating device with light of about 300 nm for 2 to 6 minutes using a HI40 lamp. After curing by light irradiation, curing by heat is performed. This thermal curing is usually
It is performed at 100 to 150 ° C. for 5 to 120 minutes. Thus, a highly translucent film can be obtained.

The article of the present invention is provided with a highly light-transmitting film by the first or second method for producing a highly light-transmitting film.
Examples of such an article include a filter such as a liquid crystal display and a TV cathode-ray tube, a showcase, a lens and a light.

[0031]

EXAMPLES Production Example 1 Silane coupling having a fluorine chain
Of Silicate Compound Treated with Coating Agent Part 1 KBM7103 (silane coupling agent having a structure of CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , manufactured by Shin-Etsu Chemical Co., Ltd.) 2
7.28 g (0.125 mol) and methanol 6.
To 82 g, 2.25 g of 0.01 N hydrochloric acid (0.125 mol
l) was added dropwise while maintaining the temperature of the reaction system at 40 ° C or lower. Here, MKC silicate 51 (hydrolyzed condensate of methyl silicate, refractive index 1.392, manufactured by Mitsubishi Chemical Corporation) 1
3.09 g (0.025 mol) was added, and the mixture was reacted under reflux for 3 hours. Then, after heating, methanol was distilled off, and then heated to 135 ° C. while blowing nitrogen gas,
This temperature was maintained for 5 hours. The thus obtained silicate compound after treatment has a weight average molecular weight of 1250, a refractive index of 1.375, and a residual amount of silanol of 150 ppm.
Met. It was inferred from the result of the molecular weight measurement that the silicate compound after this treatment had a structure in which five trifluoroethylene groups were introduced into MKC silicate 51.

Production Example 2 Silane cup having a fluorine chain
Production of silicate compound treated with ring agent 2 The same procedure as in Production Example 1 was carried out except that 19 g (0.125 mol) of tetramethoxysilane was used instead of MKC silicate 51, and the weight average molecular weight was 1,000,
Refractive index is 1.372, residual amount of silanol is 120pp
m was obtained after the treatment. It was inferred from the results of the molecular weight measurement that the silicate compound after this treatment had a structure in which three trifluoroethylene groups were introduced into a compound obtained by condensing five molecules of tetramethoxysilane.

Example 1 10 g of the silicate compound treated with the silane coupling agent having a fluorine chain obtained in Production Example 1 and 0.2 g of acetoacetoxyaluminum were dissolved in 10 g of butyl acetate. This was applied to a base material of polycarbonate having a light transmittance of 91% using a bar coater # 5.
By heating for 0 minutes, a substrate having a film formed on the surface was obtained.

For comparison, MKC silicate 51 and GH-100 were used instead of the above silicate compound.
(Fluorine silicate having a hydrolyzable fluorine chain, manufactured by Daikin Industries, Ltd.) was used to form a film on polycarbonate. The thickness of the film thus obtained was 7 to 10 μm.

The light transmittance of the substrate on which these films are formed is
It was measured with a haze meter (HGM-30P, manufactured by Suga Test Instruments Co., Ltd.). Further, the transmittance of the substrate on which each of the films was formed was measured under the humidity conditions of 60 ° C. and 90% RH for one week, and the transmittance was similarly measured. Table 1 shows the results.

[0036]

[Table 1]

Example 2 10 g of the silicate compound treated with the silane coupling agent having a fluorine chain obtained in Production Example 2 and 0.2 g of acetoacetoxyaluminum were dissolved in 10 g of butyl acetate. This was applied to one side of a PET plate having a refractive index of 1.56 using a bar coater # 15.
After heating for another minute, a film was formed on the other side in the same manner.

The light transmittance of the PET plate having the film formed on both sides was measured by the haze meter and found to be 93%. The pencil hardness is 3H, and the HB of the PET plate is
However, in a grid test based on JIS K5400, a 100/100 result was obtained, and the material was flexible and did not crack when bent. Further, in the film after one week under the humidity resistance condition of 60 ° C. and 90% RH, abnormalities such as cracks and decrease in light transmittance were not observed.

Example 3 2 g of the silicate compound treated with the silane coupling agent having a fluorine chain obtained in Production Example 2, 5 g of the photocurable material shown in Table 2, respectively, and Irgacure 651 (Ciba-Geigy) as a photoinitiator 0.28 g of benzyl dimethyl ketal (manufactured by the Company) and 0.1 g of each of the silicate curing catalysts shown in Table 2 in 5 g of butyl acetate.
To give coating compositions 1 to 5. These were applied to a substrate (polycarbonate (refractive index: 1.56)) with a bar coater # 15, and heated at 80 ° C. for 5 minutes.
Using a high-speed UV irradiator L-515 manufactured by Nippon Battery Co., Ltd. equipped with 40 N, the lower end of the lamp lamp 8 at 80 W / cm
Irradiation was performed at a height of 5 cm and a conveyor speed of 5 m / min. Thereafter, heating was performed at 120 ° C. for 30 minutes to form a film having a thickness of 7 to 10 μm on the surface of the base material.

For these, the light transmittance was measured by a haze meter, and the curability was evaluated by the presence or absence of finger touch on the film surface. Together with these results, the light transmittance of the polycarbonate as the base material, and the theoretical value of the light transmittance when a silicate compound treated with a silane coupling agent having a fluorine chain and a photocurable material are laminated. It is shown in Table 2.

[0041]

[Table 2]

The abbreviations in the table are as follows. In addition, since the film obtained from the coating composition 5 had a finger touch feeling, the light transmittance could not be measured. TMM3: NK ester A-TMM3 (tetramethylolethane triacrylate manufactured by Shin-Nakamura Chemical Co.) TMM4: NK ester A-TMMT (tetramethylolethane tetraacrylate manufactured by Shin-Nakamura Chemical Co.) TMM3-Si: NK ester A-TMM3 Terminal OH
CG: N, N, N-dimethyl (p-methoxybenzyl)
Anilinium p-dodecylbenzene sulfonate AA: acetoacetoxy aluminum

From the results of Examples 1 and 2, the film obtained by the first manufacturing method of the present invention has a high translucency,
It was confirmed that the surface hardness was high and the performance did not decrease over time. On the other hand, when a fluorine silicate having a hydrolyzable fluorine chain is used, a highly translucent film is obtained, but under moisture-resistant conditions where hydrolysis is considered to proceed, the translucency decreases. I have.

On the other hand, in Example 3, by using a coating composition in which the refractive index of the photocurable material was set between the refractive index of the silicate compound and the refractive index of the base material, a light transmission higher than the theoretical value was obtained. Rate was obtained. This is presumably because the migration of the silicate compound to the surface is performed with an inclination, so that a property different from that obtained by simply stacking two materials appears. Furthermore, a film having excellent light transmittance was obtained by using a silicate curing catalyst having a thermal latent property.

[0045]

The film obtained by the production method of the present invention has a high light-transmitting property, has a high surface hardness despite the use of a fluorine material, and its performance does not decrease over time. This is because a silicate compound that does not lose its fluorine chain even if it has sufficient curability and hydrolysis is used.

On the other hand, in the coating composition containing the silicate compound and the photocurable material, in particular, the refractive index of the photocurable material is set between the refractive index of the silicate compound and the refractive index of the substrate. Thus, a higher light transmittance can be obtained than in a case where each material is separately used and stacked. Further, by using a silicate curing catalyst having a potential, a film having more excellent performance can be obtained.

The article provided with the film obtained by the production method of the present invention can be widely used in the field of, for example, a liquid crystal display and a filter of a TV cathode-ray tube by utilizing the high light-transmitting property.

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Claims (8)

[Claims] 1. A method for producing a highly translucent film, comprising applying a silicate compound treated with a silane coupling agent having a fluorine chain to a substrate and curing the silicate compound. 2. A) a silicate compound treated with a silane coupling agent having a fluorine chain; B) a photocurable material;
A method for producing a highly translucent film, comprising applying a coating composition containing C) a photoinitiator and D) a silicate curing catalyst to a substrate and curing the substrate. 3. The method for producing a highly translucent film according to claim 2, wherein said curing is performed by irradiation with light and then by heat. 4. The method according to claim 2, wherein the refractive index of the B) photocurable material is located between the refractive index of the A) silicate compound and the refractive index of the substrate. A method for manufacturing a highly translucent film. 5. The method for producing a highly translucent film according to claim 2, wherein the D) silicate curing catalyst has a photolatent property. 6. The method for producing a highly translucent film according to claim 2, wherein the D) silicate curing catalyst has a thermal potential. 7. A) a silicate compound treated with a silane coupling agent having a fluorine chain, B) a photocurable material,
A coating composition comprising C) a photoinitiator and D) a silicate curing catalyst. 8. An article provided with a highly light-transmitting film obtained by the method according to claim 1.