JP2002316089A - Method of making anti-fogging film and anti-fogging article treated by this method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an anti-fogging film provided with anti-fogging persistence and scratching resistance without the occurrence of the deterioration in the anti-fogging performance and scratching resistance at a base material. SOLUTION: A coating film is impregnated and immobilized with an anti- fogging material, by which the anti-fogging material is uniformly distributed at a high density near the extreme surface of the coating film and the anti- fogging film having the excellent anti-fogging persistence and scratching resistance is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an anti-fogging film having excellent anti-fogging sustaining performance and excellent surface hardness, and an anti-fogging article treated by the method.

[0002]

2. Description of the Related Art As a method for imparting anti-fog performance to a substrate,
Conventionally, various methods described below have been adopted.

[0003] The simplest means is to apply a surfactant to the surface to make the substrate surface hydrophilic and prevent fogging.

Further, in order to expect continuous effects, a surfactant is kneaded into the synthetic resin base material itself, or a hydrophilic or
There is a method of forming a synthetic resin substrate by copolymerizing a water-absorbing monomer to impart anti-fog performance. This is disclosed in, for example, JP-A-10-114035, JP-A-10-130511, JP-A-10-158453, JP-A-10-182912, and JP-A-10-202798.

Further, a method of kneading an antifogging substance on the surface of a resin material to form a coating having antifogging performance is well known, as disclosed in JP-A-8-17646 and JP-A-8-2729.
1, JP-A-9-136374, JP-A-9-15136
8, JP-A-9-155282 and the like.

[0006] The method described above is intended to impart hydrophilicity and water absorption to a substrate itself or a thick coating film to achieve anti-fog performance.

On the other hand, as a method for directly imparting anti-fog performance to an inorganic substance such as glass having poor water absorption, a method of treating the outermost surface to have hydrophilicity or hydrophobicity, or a method of making the inorganic substance porous. There are known a method of imparting water absorption and a method of forming a photocatalytic metal oxide film to exhibit superhydrophilicity.

[0008] Graft polymerization as a method of surface modification includes:
It is disclosed in JP-A-5-202216, JP-A-5-295139, JP-A-8-176328, JP-A-9-301742, JP-A-10-90503, and the like. Other surface modification methods are described in JP-A-10-114543 and
167768.

Further, Japanese Patent Application Laid-Open Nos. 9-202651 and 9-29583 disclose patents combining pores / concavities and convexities of an inorganic substance with a hydrophilic substance and patents utilizing surface irregularities.
5, JP-A-11-77876.

Various patents have been filed for a method of expressing a superhydrophilic function using a photocatalytic metal oxide, and Japanese Patent Application Laid-Open Nos. 9-77535, 10-68091, 10-85100, and 10-85. 167727 and JP-A-10-297940.

In order to impart anti-fog performance to an optical article, including the methods described above, 1) the substrate is made to have water absorption.
2) Make the substrate surface hydrophilic. 3) Make the substrate surface hydrophobic. 4) Increase the surface temperature of the optical article so that moisture in the air does not condense on the surface. The above four methods have been proposed in the past, and various attempts have been made.

[0012]

However, the conventional method has the following problems.

As a method for imparting antifogging performance to the surface of a substrate, a commonly used method of applying a surfactant to the surface is such that the surfactant is easily dropped off by water, and there is a problem in sustainability. is there.

A method of imparting anti-fogging performance by kneading an anti-fogging substance into the resin substrate itself or the coating film can obtain sufficient performance as anti-fogging performance, but the anti-fogging substance is not suitable for its affinity. They were easily present locally, and were soft and very easily scratched because they were organic substances. Also,
Since the hydrophilic substance is dissolved by water and washed away, there is a problem in the antifogging durability. Furthermore, even when a water-absorbent resin is used in combination to improve the durability, the water-absorbent resin becomes very soft and easily scratched when it absorbs water. When these are used for parts requiring abrasion resistance, such as spectacle lenses, the scratches deteriorate the optical characteristics, making practical use impossible. further,
Dirt in the air, such as cigarette smoke, is also easily adsorbed, and the optical article is colored.

In the case of imparting hydrophobicity, the contact angle of water on the surface is about 160 ° in the conventional technique, but in the case of minute water droplets such as cloudy, the water drops by its own weight. And it is hard to say that sufficient anti-fog performance has been obtained.

With respect to the method of making inorganic porous and imparting water absorption, the surface itself becomes brittle and easily broken by making porous. Further, in the method of forming a photocatalytic metal oxide film and exhibiting superhydrophilicity, high-temperature sintering is required in the film forming step, and it is impossible to use the resin base material. Further, the photocatalytic metal oxide film generally has a high refractive index, and must be used on the outermost surface in order to use the superhydrophilic function efficiently. as a result,
The reflectivity is large, which is not suitable for a substrate having a controlled reflectivity such as a lens.

Accordingly, an object of the present invention is to provide a method for producing an anti-fogging film which solves the above problems and an anti-fogging article treated by the method.

[0018]

According to the present invention, a coating film having a compound having a blocked isocyanate on a substrate is treated, impregnated with an antifogging substance, and active hydrogen of the antifogging substance and the blocked isocyanate are treated. The reaction is characterized by immobilizing and holding the antifogging substance and imparting antifogging sustainability.

That is, since the antifogging film according to the present invention impregnates and immobilizes the antifogging substance by post-treatment, the antifogging substance has a large amount on the surface. Therefore, it is possible to efficiently exhibit antifogging performance. Further, since the antifogging substance in the film is uniformly present in the gap on the molecular level near the surface of the coating film, there is no problem such as cloudiness of the film, and the original hardness and scratch resistance of the coating film are not impaired. In addition, it is dispersed in the film with a size close to the molecular level and is kept by the shrinkage of the coating film and chemical bonding, so there is no outflow by water, and the expansion during water absorption is suppressed to a certain amount. . Thereby, the durability of the anti-fog performance, the hardness at the time of water absorption, and the decrease in the scratch resistance can be eliminated.

The coating film used in the present invention can be applied to all coating films such as thermosetting and photocuring, but thermosetting coating is preferred from the viewpoint of handling properties. Further, the thermosetting coating preferably contains a metal oxide sol, an inorganic alkoxide and a partial hydrolyzate thereof as a main component, and preferably contains an organic component for giving some flexibility.

The blocked isocyanate used in the present invention contains a blocked isocyanate group and a functional group which binds to the coating film in the molecule. The blocked isocyanate group is not limited as long as the substance blocked in the step of reacting with the antifogging substance is dissociated and volatilized, and at the same time, the isocyanate is activated to cause a bonding reaction with the antifogging substance. The functional group that binds to the coating film is selected according to the composition of the coating film. In the above-mentioned thermosetting coating mainly composed of a metal oxide sol, an inorganic alkoxide and its partial hydrolyzate, a blocked isocyanate having an inorganic alkoxide and its partial hydrolyzate as a functional group is desirable. In the acrylic coating film, a blocked isocyanate having a functional group such as a (meth) acryloyl group is preferable.

Next, the antifogging substance used in the present invention includes surfactants such as anionic surfactants, nonionic surfactants, cationic surfactants and double-sided surfactants, and reactive derivatives thereof; Among hydrophilic polymers and the like, those having a site that reacts with isocyanate can be mentioned. An anionic surfactant having excellent permeability and wettability, and a reactive derivative thereof are desirable. The antifogging substance to be used may be a specific compound or a mixture of two or more compounds as long as they are compatible with the specific compound. Also,
When the antifogging substance is a solid, it may be used as a solution using a solvent depending on the method. In this case, the solvent has a higher boiling point than the processing temperature, and has a higher reactivity with the isocyanate than the antifogging substance. It is necessary to choose the one with low.

Specifically, examples of the anionic surfactant include alkyl sulfate, alkylbenzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl sulfosuccinic acid, alkyl diphenyl ether disulfonic acid, alkyl phosphoric acid, polyoxyethylene alkyl (or (Alkyl allyl) sulfate, polyoxyethylene alkyl phosphate, and the like. Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene mono fatty acid esters, polyoxyethylene monofatty acid esters, and polyoxyethylene monofatty acid esters. Examples include ethylene alkylamine, polyoxyethylene hydrogenated castor oil, and alkyl alkanolamides.

Examples of the cationic surfactant and the double-sided surfactant include alkylamine salts; alkylamide betaine, imidazolium betaine, and amine oxide.

Examples of the hydrophilic polymer include a hydrophilic polymer having a polyether group, a cellulose derivative, polyvinylpyrrolidone, and polyvinyl alcohol.

Examples of the hydrophilic polymer having a polyether group include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol. As cellulose derivatives,
Viscose, methyl cellulose, carboxymethyl cellulose and the like.

Next, a method of impregnating a coating film with an antifogging substance is not particularly limited as long as the substance has an effect of contacting the coating film and penetrating into the film. Specifically, general dyeing or a method using the same is used. For example, a method of immersing the coated substrate in an antifogging substance or a solution, swelling and impregnating the substrate,
A method of immersing, heating and impregnating a coated substrate in an antifogging substance or solution, a method of impregnating a coating film in contact with the antifogging substance or solution and impregnating it, a method of preventing a relatively low molecular weight. Examples of the method include a method of vaporizing a fogging substance and using it like a sublimation dye for infiltration and impregnation, and a method of heat-transferring and impregnating an antifogging substance to a coating film.

With respect to the method of reacting the antifogging substance with the blocked isocyanate, after impregnating the antifogging substance,
Alternatively, heating is performed simultaneously with impregnation, and the block portion is dissociated.

The optical article having antifogging performance obtained by the present invention has excellent scratch resistance and optical properties such as anti-reflection, and is used for spectacle lenses, camera lenses, mirrors in bathrooms, underwater glasses, windows. The present invention can be applied to glass, microwave oven windows, car window glasses, telescope lenses, ski goggles, lenses of optical devices used in humid places, mirrors, and the like.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Preparation of coating solution In a reaction vessel equipped with a stirrer, 445.4 g of isopropyl alcohol, 89.9 g of γ-glycidoxypropyltriethoxysilane, 31.2 g of bis [3- (diethoxymethylsilyl) propyl] carbonate, 37.1 g of 3-isocyanatopropyltriethoxysilane having an isocyanate moiety blocked with butanol, 0.05N
33.3 g of an aqueous hydrochloric acid solution was added, and the mixture was stirred for 120 minutes. Next, a silicon oxide sol ("Oscal-1" manufactured by Catalyst Chemical Industry Co., Ltd.)
432 ") 330.2 g, glycerol polyglycidyl ether 67.4 g, and silicone surfactant (Nippon Unicar Co., Ltd." L-7604 ") 0.3 g were added,
After sufficiently stirring, a coating liquid was obtained.

2. Coating treatment Pre-soaked in sodium hydroxide solution (0.1N), washed well with water, and dried plastic lens (Seiko Epson)
Co., Ltd., Seiko Super Frontier lens fabric,
1. Refractive index 1.56). The coating liquid adjusted in the above was applied by dipping to a thickness of 3.5 μm.
Heated at 0 ° C. for 45 minutes.

3. Anti-fogging agent treatment The coated lens substrate was previously 135 ° C
Immersed in polyoxyethylene alkyl ether phosphoric acid, heated for 120 minutes, and then gradually cooled at 1 ° C./min.
The lens that had been returned to room temperature was taken out and wiped with acetone in lens paper. No major change was seen in the appearance of the lens.

The method for evaluating the antifogging property of the obtained antifogging film is as follows.
"JIS-S4030 Test method for anti-fog agent for glasses"
According to the anti-fog properties of low-temperature parts, the evaluation was made in grades 1 to 4 (grade 1 has the best antifogging performance and grade 4 has the worst). Also,
The abrasion resistance was measured using a Bonstar # 0000 steel wool (manufactured by Nippon Steel Wool Co., Ltd.) under a 1 kg load,
How to scratch when rubbing the reciprocating surface (A: 1cm * 3
There is no scratch in the range of cm. B: 1 within the above range
10 to 10 scratches. C: 11 to 100 scratches are made in the above range. D: Countless scratches are formed within the above range. ). The antifogging performance persistence was evaluated by holding at a temperature of 40 ° C. and a relative humidity of 90% for 60 minutes, and then performing the above-described antifogging evaluation. The evaluation results are summarized in Table 1. [Example 2] A substrate coated in the same manner as in Example 1 was immersed in a methacrylic acid ester-based acidic phosphoric acid ester preliminarily heated to 50 ° C, kept for 120 minutes, taken out of the lens, and then subjected to anti-fogging property. After removing the material, 135
The temperature was raised to ° C. and heat treatment was performed for 60 minutes. No major change was observed in the appearance of the lens. [Example 3] The coating solution prepared in Example 1 was applied to a lens material and heated at 90 ° C for 180 minutes. Next, this was immersed in polyoxyethylene alkylphenyl ether, and subjected to pressure treatment and heat treatment at 120 ° C. for 60 minutes in an autoclave. The lens which had been returned to room temperature was washed with pure water and evaluated. No change was observed in the appearance of the lens. [Example 4] The coating solution prepared in Example 1 was applied to a lens material and heated at 90 ° C for 180 minutes. This is immersed in sorbitan fatty acid ester,
A pressure treatment was performed at a temperature of 3 ° C. for 3 minutes. Thereafter, while being immersed in the antifogging substance, it was heated at 135 ° C. for 120 minutes at normal pressure to fix the antifogging substance. No significant change was observed in the appearance of the lens after processing. [Example 5] The coating solution prepared in Example 1 was applied to a lens cloth and heated at 90 ° C for 180 minutes. This was immersed in polyoxyethylene alkylamine and subjected to a pressure treatment at 60 ° C., 3 atm for 30 minutes.
Thereafter, the antifogging substance was removed, and the mixture was heated at 135 ° C. for 120 minutes under normal pressure to fix the antifogging substance. No significant change was observed in the appearance of the lens after processing. [Example 6] UV-curable hard coat UVHC110
5 (manufactured by GE Toshiba Silicone Co., Ltd.) mixed with 10 g of p-allylphenyl isocyanate blocked with mercaptophenol was used as a coating liquid. This solution was applied to an allyl carbonate-based resin lens substrate (CR-39), and irradiated with ultraviolet light for 1 second using a high-pressure mercury lamp of 80 W / cm. This was immersed in glycerin fatty acid ester and subjected to a pressure treatment at 60 ° C., 3 atm for 30 minutes. Thereafter, the antifogging substance was removed, and the temperature was 135 ° C. at normal pressure.
For 120 minutes to fix the anti-fogging substance. No significant change was observed in the appearance of the lens after processing.

Comparative Example 1 A substrate coated in the same manner as in Example 1 was heated at 135 ° C. for 150 minutes to obtain Comparative Example 1. [Comparative Example 2] 7.5 g of polyoxyethylene alkyl ether phosphoric acid was mixed with the coating solution prepared in Example 1 and applied to a lens material by dipping so as to have a thickness of 2.5 µm. After heating, the temperature was raised to 135 ° C. and heating was performed for 2 hours. The resulting lens was slightly opaque in appearance. [Comparative Example 3] A substrate coated in the same manner as in Example 1 was heated at 135 ° C for 150 minutes, and then a 0.5 wt% aqueous solution of polyoxyethylene alkylphenyl ether was applied thereto by spin coating. For 10 minutes. No major change was observed in the appearance of the obtained lens.

[0036]

[Table 1]

According to the present invention, the antifogging substance can be optimally distributed in the film and the heavy weight of the antifogging substance can be present on the outermost surface. Thus, the production of an antifogging article having excellent antifogging performance and abrasion resistance became possible by immobilizing the antifogging article.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C03C 17/30 C03C 17/32 A 17/32 G02B 1/10 Z F term (Reference) 2H042 DB11 DE00 DE01 DE08 2K009 AA15 CC03 CC24 CC42 CC47 DD02 EE02 4D075 AB01 AB16 CA02 CA39 DA06 DB13 DC01 DC05 DC13 DC19 DC24 DC38 EA07 EA19 EA21 EB19 EB22 EB45 EB56 EC07 4G059 AA01 AB11 AC21 AC24 FA01 AB04 FA05 FA07 AB07 4H

Claims (5)

[Claims] 1. A method for producing an anti-fogging film, comprising forming a coating film containing a blocked isocyanate on a substrate, impregnating and holding an anti-fogging substance, and imparting anti-fogging property. . 2. The method for retaining an antifogging substance according to claim 1, wherein the blocked isocyanate reacts with active hydrogen of the antifogging substance to fix and retain the antifogging substance. A method for producing an anti-fogging film. 3. The method of impregnating an antifogging substance according to claim 1, wherein the coating film provided on the substrate is immersed in an antifogging substance or a solution of the antifogging substance, swelled and impregnated, and further treated with a blocked isocyanate. 2. The method for producing an anti-fogging film according to claim 1, wherein the reaction is carried out with a reactive substance. 4. The method for impregnating an antifogging substance according to claim 1, wherein the coating film provided on the substrate is impregnated with a coating film or a solution of the antifogging substance by applying pressure to the coating film. 2. A reaction with a substance is performed.
A method for producing the antifogging film according to the above. 5. An anti-fogging article produced by the method for producing an anti-fogging film according to claim 1.