JP2005110918A - Anti-fogging mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-fogging mirror which immediately gets anti-fogging in a foggy situation without incidental equipments like a heating device, a spout or a water receiving device, and is excellent in maintaining the anti-fogging property, and is preferably excellent in durability. <P>SOLUTION: In an anti-fogging mirror provided with a mirror body and a film coherent to the mirror body, the film is an absorbent and hydrophilic film, and the contact angle of drops to the film is 40 degrees or less in conditions that the film does not absorb water, and the water absorption rate of the film is 15% of the weight or more and 30% of the weight or less when the film is saturated with absorbed water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an anti-fog mirror that can be suitably used in a bathroom (especially a vanity), a changing room, a bathroom, a shower room or the like adjacent to a bathroom, a shower room or the like.

  The washroom and changing room are usually adjacent to the bathroom, and the mirror installed in the bathroom is clouded by the influence of water vapor from the bathroom. In order to prevent this fogging, a method for preventing condensation mainly by electrically heating the back surface of the mirror has been used (for example, Patent Document 1).

  The anti-fogging mirror by this method has a problem that it takes time until the anti-fogging property is exhibited after heating starts after the mirror starts to cloud. In addition, the heating may cause a problem that the moisture of the attached dirt (for example, toothpaste) is scattered and the dirt is fixed.

  In Patent Document 2, in order to solve the above problem, a mirror body, means for discharging water on the mirror surface (water discharge means), and means for receiving water (water receiving means) that has flowed along the mirror surface are provided. Disclosed are an anti-fogging and antifouling mirror having a feature, and an antifogging and antifouling mirror having a hydrophilic surface by having a fine concavo-convex structure on a mirror surface as a preferred embodiment. However, the anti-fogging mirror is one that causes water to flow on the surface by water discharge means after the mirror surface starts to become cloudy, and develops anti-fogging property, in a state where water vapor etc. is in contact with the mirror surface, that is, a cloudy environment In addition, instant antifogging properties are difficult to be exhibited, and an incidental facility having water discharge means and water reception means is required.

In order to solve the above-described problem, a method of developing antifogging properties by coating a water-absorbing coating composition on a mirror surface and providing a water-absorbing (hygroscopic) film has been proposed (for example, Patent Document 3). However, the anti-fogging mirror based on the water absorption of the coating has a problem that water absorption is immediately saturated and the anti-fogging property is not exhibited in a humid place such as a bathroom or the vicinity thereof.
JP-A-08-317841 JP 2000-237014 A JP 2001-040294 A

  The present invention does not require ancillary equipment such as a heating means, a water discharge means, a water receiving means, instantly exhibits an antifogging property even in a cloudy environment, and is excellent in antifogging durability. It is an object of the present invention to provide an antifogging mirror that is preferably excellent in durability.

  In order to immediately exhibit antifogging properties when water vapor comes into contact with the coating, it is necessary to instantaneously take water droplets into the coating or into a water film formed on the coating. When the function of the coating is only water absorption, it takes time for water droplets to be absorbed into the coating when water vapor contacts the coating, and thus it takes time to develop antifogging properties. By providing water-absorbing and hydrophilic functions to the film, water and the film come into contact with each other over a wider area when water droplets come into contact with the surface of the film, facilitating water absorption into the film. The As a result, it is possible to immediately exhibit antifogging properties when water vapor contacts the coating.

  Even when the water absorption is saturated, the film surface is hydrophilic, so that a water film is formed on the film. In contrast to the formation of a water film on the film, the water absorbed by the film also contributes to the formation of the water film. Therefore, the antifogging mirror can maintain the antifogging property even after the water absorption of the coating is saturated.

  The present invention has been made based on the above technical idea, and the anti-fog mirror of the present invention is an anti-fog mirror having a mirror body and a film in close contact with the mirror body, and the film has a contact angle of water droplets. The film exhibits hydrophilicity of 40 ° or less in a state where water is not absorbed, and has a water absorption rate of 15% or more and 30% or less at the time of water absorption saturation. Here, the film in close contact with the mirror refers to a film that is not peeled off by an artificial operation such as scratching, and that does not elute the film itself or components in the film over time. In addition, the water absorption rate in the present invention indicates the weight ratio of water present in the coating film based on the weight of the coating film in the state of not absorbing water.

  By setting the contact angle of water droplets to the coating to be 40 ° or less as described above, water absorption into the coating is promoted, and instant development of antifogging properties becomes possible. The smaller the contact angle is, the better the antifogging property is. However, if the contact angle is set to be small, the durability of the coating film may be deteriorated. From a practical viewpoint, the contact angle is preferably 10 ° or more. More preferably, the angle is preferably 25 ° or more and 35 ° or less. Here, the contact angle of water droplets on the coating is the contact angle when 2 μl of water is dropped on the surface of the coating that is not absorbing water.

  Also, the water absorption rate to the coating at the time of water absorption saturation is set in the above range. If it is less than 15% by weight, the antifogging effect due to the water absorption function is not effective, and if it exceeds 30% by weight, the coating durability This is because it must be made worse. By setting the water absorption rate to the film at the time of water absorption saturation to 15% by weight or more and 30% by weight or less, the film surface becomes super hydrophilic when the film is saturated with water absorption (the contact angle of water droplets is 10 ° or less). State) and the antifogging property is maintained even when the film is saturated with water.

  In addition, in order to obtain a sufficient water-absorbing function of the film, the film thickness is preferably 5 μm or more. As the film thickness is increased, the water absorption capacity of the film is increased. However, if the film is too thick, optical distortion tends to occur and productivity is reduced.

The water absorbing function can be efficiently performed by introducing an oxyethylene chain [—CH ₂ CH ₂ O—] into the coating. This oxyethylene chain has a function of absorbing water as bound water and makes it possible to develop antifogging properties due to water absorption. Since water forms hydrogen bonds with oxygen in the oxyethylene chain, when water is absorbed by the coating, a hydroxyl group is generated at the chain. When the water absorption in the film reaches saturation, the hydroxyl group appears on the surface of the film, which is preferable because formation of a water film on the film is promoted.

  In view of the durability of the antifogging mirror, it is preferable to set the pencil hardness of the coating obtained in accordance with “JIS K 5400” in the range of HB to F when the coating is saturated with water absorption.

  The antifogging mirror of the present invention does not require any additional equipment such as heating means, water discharging means, and water receiving means, and immediately develops antifogging properties even in a cloudy environment, and makes the antifogging sustainability. Since it has the effect of being excellent, it is particularly effective when used in applications such as a bathroom, a bathroom vanity, a changing room, and a shower room where water vapor is likely to be generated, and a comfortable living environment can be provided to the user.

  The anti-fogging mirror of the present invention comprises a mirror body and a coating that is in close contact with the mirror body. The mirror body is made of a glass mirror in which a metal film is formed on a soda lime silicate glass produced by a float method or the like by a silvering method or a vacuum deposition method. A glass (so-called cold mirror) on which a multilayer film is formed, a plastic mirror such as polycarbonate or polyethylene terephthalate, a metal mirror (so-called surface mirror) made of stainless steel, bronze, or the like can be used. The coating on the mirror body can be formed on the entire surface or a part of the mirror.

  As the film having the function described in the section [Means for Solving the Problems], a film made of polyurethane can be preferably used. This is because polyurethane has elasticity unique to urethane and is therefore superior in wear resistance compared to other resins. In consideration of economy, the coating is preferably made of a resin alone. Polyurethane is obtained by reacting an isocyanate prepolymer and a polyol, and the function of the film can be set by appropriately selecting the polyol. The isocyanate prepolymer, polyol, and other chemical species, and / or their reactants can be added. A coating can be obtained by applying the coating agent having the coating to the mirror body by a known coating means such as spin coating, dip coating, or flow coating, and curing. At this time, it is preferable to adjust the number of isocyanate groups and isocyanate-reactive groups in the vicinity of the stoichiometry. Further, in order to further improve the durability of the antifogging mirror, a treatment for improving the adhesive strength between the mirror body and the coating film can be performed in advance on the mirror body.

  As the isocyanate prepolymer, difunctional, preferably trifunctional polyisocyanate having a biuret and / or isocyanurate structure starting from hexamethylene diisocyanate can be used. The substance has weather resistance, chemical resistance and heat resistance, and is particularly effective for weather resistance. In addition to the above substances, diisophorone diisocyanate, diphenylmethane diisocyanate, bis (methylcyclohexyl) diisocyanate, toluene diisocyanate and the like can also be used.

  In order to give the coating water absorbability, an oligomeric water absorbable polyol can be used as the polyol. The water-absorbing polyol has the property of absorbing water and swells, and the hydroxyl group in the molecule reacts with the isocyanate group of the isocyanate prepolymer to form a urethane bond, thereby introducing the water-absorbing property to the polyurethane. Can do. The water-absorbing polyol may have water-soluble properties.

  The amount of water-absorbing polyol used is adjusted so that the water absorption rate in the coating at the time of water absorption saturation is 15% by weight or more, and the amount of water-absorbing component derived from the water-absorbing polyol in the coating is adjusted. The water-absorbing component may be derived from an oxyalkylene-based polyol, preferably has an oxyethylene chain, an oxypropylene chain, etc., and particularly preferably has an oxyethylene chain excellent in water absorption.

  The oxyalkylene polyol preferably has a number average molecular weight of 400 to 5,000. When the number average molecular weight is less than 400, the ability to absorb water as bound water becomes low, and when the average molecular weight exceeds 5000, the strength of the coating tends to decrease. In view of water absorption and film strength, the average molecular weight is more preferably 400-4500. As the polyol, an oxyethylene / oxypropylene copolymer polyol, polyethylene glycol, or the like can be used. When polyethylene glycol is used, the number average molecular weight is 400 to 2000 in view of water absorption and the strength of the resulting film. It is preferable to do.

  A typical chemical species that imparts hydrophilicity to the film is a surfactant. In order to prevent the surfactant from eluting from the coating, it is preferable that the surfactant is present in the coating in a state of being bonded to the resin crosslinking. In order to be in a state of being bonded to the resin crosslinking, it is necessary to use a surfactant containing a reactive group as a surfactant starting material. When the reactive group is a hydroxyl group, an amino group, a mercapto group or the like, the reactive group reacts with the isocyanate prepolymer, and the surfactant can be chemically bonded to the resin crosslinking. Further, an isocyanate group can be provided on the surfactant and reacted with a polyol.

  Anionic surfactants containing reactive groups that react with isocyanate groups include castor oil monosulfate, castor oil monophosphate, sorbitan fatty acid ester sulfate, sorbitan fatty acid ester phosphate, sorbitol fatty acid ester sulfate, sorbitol fatty acid ester phosphate, sucrose fatty acid ester Sulfate, sucrose fatty acid ester phosphate, polyoxyalkylene castor oil ether monosulfate, polyoxyalkylene castor oil ether monophosphate, polyoxyalkylene sorbitan fatty acid ester sulfate, polyoxyalkylene sorbitan fatty acid ester phosphate, polyoxyalkylene glycerine ether monosulfate, polyoxy Alkylene glycerin ether mono Sufeto, and the like.

  Cationic surfactants containing reactive groups that react with isocyanate groups include dialkanolamine salts, trialkanolamine salts, polyoxyalkylene alkylamine ether salts, fatty acid trialkanolamine ester salts, polyoxyalkylene dialkanolamine ethers Salt, polyoxyalkylene trialkanolamine ether salt, di (polyoxyalkylene) alkylbenzylalkylammonium salt, alkylcarbamoylmethyldi (polyoxyalkylene) ammonium salt, polyoxyalkylenealkylammonium salt, polyoxyalkylenedialkylammonium salt, Examples include noreamidopropylethyl dimonium ethosulphate and the like.

  Examples of the zwitterionic surfactant containing a reactive group that reacts with an isocyanate group include N, N-di (β-hydroxyalkyl) N-hydroxyethyl-N-carboxyalkylammonium betaine, N-β-hydroxyalkyl-N. , N-dipolyoxyalkylene-N-carboxyalkylammonium betaine, N-alkyl-N, N-di (polyoxyalkylene) amine and dicarboxylic acid monoester, N- (polyoxyethylene) -N ′, N ′ -Di (polyoxyethylene) aminoalkyl-N-alkyl-N-sulfoalkylammonium betaine, N, N-di (polyoxyethylene) -N-alkyl-N-sulfoalkylammonium betaine, N- (β-hydroxyalkyl Aminoethyl) -N- (β-hydroxyalkyl) aminoethylcarbo Acid, N, N′-bis (2-hydroxyalkyl) -N, N′-bis (carboxyethyl) ethylenediamine salt, N- (β-hydroxyalkyl) -N ′, N′-di (polyoxyethylene) -N-carboxyethyl ethylenediamine salt etc. are mentioned.

  Nonionic surfactants containing reactive groups that react with isocyanate groups include polyoxyethylene polyoxypropylene block polymers, sorbitol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, fatty acid monoglycerides , Polyoxyalkylene fatty acid monoglyceride, polyglycerin fatty acid ester, polyoxyalkylene castor oil ether, polyoxyalkylene alkylamine polyoxyalkylene alkylamide, and the like.

  The chemical species that imparts hydrophilicity to the coating can be introduced into the coating such that the contact angle of water droplets in a state where the coating does not absorb water is 40 ° or less. However, since excessive introduction of chemical species weakens the strength of the coating and deteriorates durability, it is preferable to introduce the chemical species so that the contact angle is 10 ° or more.

  The isocyanate prepolymer may be a diisocyanate, preferably a trifunctional polyisocyanate having a biuret and / or isocyanurate structure starting from hexamethylene diisocyanate. The substance has weather resistance, chemical resistance and heat resistance, and is particularly effective for weather resistance. In addition to the above substances, diisophorone diisocyanate, diphenylmethane diisocyanate, bis (methylcyclohexyl) diisocyanate, toluene diisocyanate and the like can also be used.

  The above are the requirements necessary for obtaining a film having a water-absorbing function and a hydrophilic function by polyurethane. In addition to the above, the polyol includes a hydrophobic polyol and a short-chain polyol having a number average molecular weight of 60 to 200 Can be used.

  The hydrophobic polyol has both flexibility and scratch resistance, and it is difficult to reduce the water absorption function and hydrophilic function of the film, and as a result, the water resistance and abrasion resistance of the film can be improved. It is preferable that it is a polyester polyol having a number average molecular weight of 500 to 2,000. When the number average molecular weight is less than 500, the coating film becomes too dense and wear resistance decreases. On the other hand, if it exceeds 2000, the film formability of the coating solution deteriorates and it becomes difficult to form a coating film. In consideration of the denseness of the resulting film, the polyol preferably has 2 or 3 hydroxyl groups.

  As the polyester polyol, any of polycarbonate polyol, polycaprolactone polyol, and a mixture thereof can be used. The hydrophobic components derived from these hydrophobic polyols are introduced so that the water absorption rate and water droplet contact angle of the coating are in the above-mentioned ranges, and the pencil hardness of the coating obtained in accordance with “JIS K 5400” is preferably When the water absorption is saturated, it is introduced so as to be HB to F.

  In addition, the component derived from the short-chain polyol has the effect of increasing the curability of the coating solution, increasing the strength of the coating film, and reducing the static friction coefficient of the coating surface. Antifogging mirrors are easily assumed to have a wide variety of deposits on the surface of the film during use, impairing the appearance and quality, and in order to remove these deposits, usually with a cloth or the like. Wiping is performed. At that time, if the static friction coefficient of the surface is large, problems such as an increase in removal time and poor appearance due to uneven wiping occur in the wiping operation. During the wiping operation, the deposits are rubbed against the film surface. If the coefficient of friction is large, the deposits are likely to be caught on the film surface, and many scratches may be generated, and the cloth used for the wiping operation may be reversed. Adverse effects such as sticking to the surface may occur. When the static friction coefficient on the film surface is small, the wear resistance and antifouling property of the film are improved, and the coefficient is a very important physical property from a practical viewpoint.

  The short chain polyol preferably has 2 or 3 hydroxyl groups. When the hydroxyl group is 1, the short-chain polyol does not become a skeleton component of the film, so that the film becomes fragile. When it exceeds 3, the reactivity is too active and the coating agent tends to be unstable.

  Short chain polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5 -Pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, glycerin, 2- And alkyl polyols such as ethyl-2- (hydroxymethyl) -1,3-propanediol, 1,2,6-hexanetriol, and 2,2′-thiodiethanol, and alkanolamines such as diethanolamine and triethanolamine. They can be used alone or as a mixture or Can be used copolymers that are not molecular weight greater than 200 and, component derived from short-chain polyols can be water absorption of the film, and contact angle of water droplet is introduced so that the range described above.

  The anti-fog mirror composed of the urethane resin film exhibiting water absorption and hydrophilicity and the mirror body is excellent in anti-fogging property due to water absorption and hydrophilicity, so that it becomes cloudy when used in a bathroom vanity or bathroom. Even if it becomes an environment, it is effective to immediately exhibit antifogging properties. In addition, the cloudy environment here refers to an environment in which condensation occurs on the entire surface of the soda-lime silicate glass by the float method having a size of 100 mm × 100 mm × 3 mm (thickness). In addition, since it is excellent in durability, it can withstand long-term use.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, quality evaluation was performed by the method shown below about the anti-fog mirror obtained by the present Example and the comparative example.

  [Appearance evaluation]: Appearance, permeability, and presence / absence of cracks of the film were visually evaluated. Those having no problem were evaluated as acceptable (◯), and those having problems were regarded as unacceptable (x).

  [Water absorption rate when the film is saturated with water absorption]: Weight of anti-fog mirror when held for 12 hours in an environment of 50% humidity and a temperature of 55 ° C. and then held in an environment of the same humidity and a temperature of 25 ° C. (a) , The film was brought into contact with saturated water vapor at 43 ° C. for 5 minutes, and immediately after wiping off the water film on the surface of the film, the weight (b) of the antifogging mirror was measured, and [b−a] / [a− ( The weight obtained by the formula of the weight of the mirror body)] × 100 (%) was defined as the water absorption rate at the time of water absorption saturation. The value (a) here corresponds to that in a state in which the film does not absorb water.

  [Contact angle of water droplets to the coating]: The contact angle of water droplets to the coating was measured in accordance with “JIS R 3257“ Test method for wettability of substrate glass surface ”. After holding for 12 hours in an environment with a humidity of 50% and a temperature of 55 ° C., it was held for 12 hours in an environment with the same humidity and a temperature of 25 ° C. to obtain a test piece in which the coating was not absorbed. It was placed on a Kyowa Interface Chemical contact angle meter (CA-2 type), 2 μl of water was dropped on the coating, and the contact angle of the water droplet was measured. The film was brought into contact with water for a minute, and the film was saturated with water. The test piece was placed on the contact angle meter, and 2 μl of water was dropped on the film to measure the contact angle of the water droplet.

    [Anti-fogging property]: According to “JIS S 4030“ Anti-fogging agent test method for spectacles ””, fogging condition when kept in steam of warm water set at 43 ° C. for 3 minutes, and normal temperature (23 ° C., humidity) 63%) Observe the cloudiness due to exhaled air when taken out during 10 cycles.This operation is performed 10 cycles, and the film appearance is normal and no cloudiness occurs. The anti-fog mirror that passes the evaluation item exhibits a remarkable effect on the expression of anti-fogging properties when used in a bathroom vanity or bathroom.

  [Pencil hardness]: In accordance with “JIS K 5400“ General paint test method ””, the surface of the film was scratched five times with a pencil with a load of 1 kg, and the pencil whose film tear was less than two times was pencil hardness. Note that the sample used was a film with saturated water absorption, and the pencil hardness can be used as an index of scratch resistance.

  [Taber abrasion resistance]: Taber 5130 type Taber tester was used. The abrasion change (CF-10F) was brought into contact with the film, and the change in fogging was measured when 500 revolutions were carried out while applying a load of 2.45 N, and those with ΔH ≦ 10 were accepted.

[Traverse wear resistance]: Appearance and anti-fogging property when nel (Cotton No. 300) was reciprocated 5000 times with a load of 4.9 N / 4 cm ² on the membrane surface. Those with abnormalities were regarded as rejected (x).

  [Water resistance]: What is immersed in water at 23 ± 2 ° C. for 1 hour, has no abnormal appearance after immersion, has not been clouded by exhalation, and has a pencil hardness reduction of within one rank. (◯) A product that deteriorated by 2 ranks or more was regarded as rejected (x).

[Slip property evaluation]: In accordance with “JIS K 7125“ Plastic-Film and Sheet—Friction Coefficient Test Method ””, a square sliding piece with a contact area of 40 cm ² (length of one side: 6.3 cm) was applied with 200 g load. The slip property was measured by placing it on an anti-fogging film, and the bottom surface of the sliding piece (the ground contact surface with the specimen) was covered with nell (cotton No. 300) assuming cloth wiping in actual use. .

  Here, those having a static friction coefficient of 0.8 or less derived from the measured values were accepted (◯), and those exceeding 0.8 were regarded as unacceptable (x). In order to improve the durability of the film by imparting slip properties, the static friction coefficient is preferably as low as possible. However, from the viewpoint of coexistence with anti-fogging properties, it can be used in the range of 0.4 to 0.8 in practice. .

Example 1
Hexamethylene diisocyanate burette type polyisocyanate (trade name “N3200”, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was prepared as an isocyanate prepolymer, and this was used as coating agent A.

  12.5 g of ricinoleamidopropylethyldimonium ethosulphate (trade name “Lipoquat®” manufactured by Lipochemicals Inc) as a surfactant having an isocyanate-reactive group, 17.5 g of polyethylene glycol having an average molecular weight of 1000 as a water-absorbing polyol 20.5 g of polycaprolactone diol having an average molecular weight of 1250 (trade name “Placcel L212AL”, manufactured by Daicel Chemical Industries) as a hydrophobic polyol, and 5 g of 1,4 butanediol as a short-chain polyol are mixed together, and this is used as coating agent B. It was.

  44.5 g of coating agent A adjusted to have an isocyanate group / isocyanate reactive group ratio of 1.2 was added to and mixed with coating agent B to obtain a mixture of coating agent A and coating agent B. .

  Diacetone alcohol was added as a diluent solvent so that the concentration of the total amount of isocyanate prepolymer, polyol, and surfactant was 35% by weight, and dibutyltin dilaurate as a curing catalyst was added to the total amount of urethane components. A coating agent for forming an antifogging film was prepared by adding 0.005% by weight.

  As the mirror body, a 300 mm × 800 mm × 5 mm (thickness) size mirror in which a reflective layer was formed on a soda lime silicate glass by a float method by a silvering method was used. The coating agent was applied to the glass surface side of the mirror by a spin coating method. The mirror on which the coating agent was applied was heated at 150 ° C. for 30 minutes to obtain an antifogging mirror on which a film having a water absorption and hydrophilicity of 28 μm was formed.

  As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 2
Example 1 except that the hydrophobic polyol was 15 g of polycaprolactone diol having an average molecular weight of 500 (trade name “Placcel L205AL” manufactured by Daicel Chemical Industries), and the amount of coating agent A added to coating agent B was 50 g. Thus, an antifogging mirror with a film having a water absorption and a hydrophilicity of 7 μm was formed. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 3
20.0 g of ricinoleamidopropylethyldimonium ethosulphate for the surfactant having an isocyanate reactive group, 20.0 g of polyethylene glycol with an average molecular weight of 1000 for water-absorbing polyol, and 5.6 g for the average molecular weight of hydrophobic polyol 1250 polycaprolactone diol and short-chain polyol were changed to 5 g ethylene glycol, and the amount of coating agent A added to coating agent B was 49.4 g so that the isocyanate group / isocyanate reactive group ratio was 1.1. Except for the above, the same operation as in Example 1 was performed to obtain an antifogging mirror on which a film exhibiting water absorption and hydrophilicity having a film thickness of 22 μm was formed. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 4
20.0 g of ricinoleamidopropylethyldimonium ethosulphate surfactant having an isocyanate-reactive group, 19.5 g of polycaprolactone diol having an average molecular weight of 1250, and 2.5 g of glycerol The same procedure as in Example 3 was performed except that the amount of the coating agent A added to the coating agent B was 38 g so that the isocyanate group / isocyanate-reactive group number ratio was 1.1, and the film thickness was 28 μm. Thus, an antifogging mirror having a water-absorbing and hydrophilic coating film was obtained. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 5
Example 4 except that 5.1 g of a polycarbonate polyol having an average molecular weight of 1250, 5 g of ethylene glycol was used as the hydrophobic polyol, and 49.9 g of the additive A was added to the coating agent B. Thus, an antifogging mirror having a film having a water absorption and hydrophilicity of 13 μm was formed. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 6
The hydrophobic polyol is 8.3 g of polycaprolactone triol having an average molecular weight of 500 (trade name “Placcel 305” manufactured by Daicel Chemical Industries), the short-chain polyol is 5 g of 1,4 butanediol, and the coating agent A is applied to the coating agent B. The same operation as in Example 3 was carried out except that the amount added was 46.7 g, to obtain an antifogging mirror having a film thickness of 29 μm and having a water-absorbing and hydrophilic film. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Example 7
The surfactant having an isocyanate-reactive group is 17.5 g of ricinoleamidopropylethyldimonium ethosulphate, the water-absorbing polyol is 15.0 g of polyethylene glycol having an average molecular weight of 1000, and 10 g of ethylene oxide is 50%. Addition of coating agent A to coating agent B with propylene oxide / ethylene oxide random triol having an average molecular weight of 2800, 13.2 g of a hydrophobic polyol, polycaprolactone diol having an average molecular weight of 500, and 2.5 g of glycerin as a short-chain polyol A coating film exhibiting water absorption and hydrophilicity with a film thickness of 19 μm, except that the mixing amount is 41.9 g so that the isocyanate group / isocyanate reactive group number ratio is 1.2. An antifogging mirror was obtained. As shown in Table 1, the obtained antifogging mirror is excellent in various properties such as antifogging performance, pencil hardness, various wear properties, water resistance and slipping properties, and has a small water droplet contact angle when the coating is saturated with water. It was confirmed that the composition was excellent in anti-fogging durability and suitable for use in a bathroom vanity or bathroom.

Comparative Example 1
The same operation as in Example 1 was carried out except that the hydrophobic polyol was not added and the water-absorbing polyol was changed to 38 g of polyethylene glycol having an average molecular weight of 1000, and a film exhibiting water absorption and hydrophilicity with a film thickness of 27 μm was formed. Got an anti-fog mirror. As shown in Table 1, it was confirmed that the obtained antifogging film was excellent in various antifogging performances, various wear resistances, water resistance, and slipping properties. As shown in Table 1, the obtained antifogging mirror was excellent in antifogging performance, but was inferior in pencil hardness, various abrasion properties, water resistance, and slipping properties, and used in a bathroom vanity or bathroom. It was unsuitable for.

Comparative Example 2
Example 1 except that a surfactant having an isocyanate-reactive group was not added, the water-absorbing polyol was changed to 27 g of polyethylene glycol having an average molecular weight of 1000, and the hydrophobic polyol was changed to 26.5 g of polycaprolactone diol having an average molecular weight of 1250. The same operation was performed to obtain an antifogging mirror on which a film having a water absorption of 27 μm was formed. As shown in Table 1, the obtained antifogging mirror has a low water droplet contact angle in a state in which the film does not absorb water, so that the antifogging property does not immediately appear, and the antifogging performance is inferior. It was unsuitable for use on a dressing table or bathroom.

Comparative Example 3
A hydrophilic agent having a film thickness of 24 μm was prepared in the same manner as in Example 1 except that the surfactant was 22 g of alkyl ether sulfate sodium having no isocyanate-reactive group and the amount of coating agent A added was 40 g. An antifogging mirror having a coating film exhibiting properties and water absorption was obtained. The resulting antifogging mirror gradually decreases in antifogging during the antifogging test, and after the test, the contact angle of water droplets in a state where the coating does not absorb water is the value before the antifogging test evaluation. It was not suitable for use in a bathroom vanity or bathroom.

Comparative Example 4
The water-absorbing polyol was 17.5 g of polypropylene glycol having an average molecular weight of 2000, and the concentration of the total amount of isocyanate prepolymer, polyol, and surfactant in adjusting the coating agent was adjusted to 40% by weight. Then, the same operation as in Example 1 was performed to obtain an antifogging mirror on which a film having a film thickness of 33 μm and having hydrophilicity and water absorption was formed. The obtained anti-fogging mirror was observed to have optical distortion in appearance. Further, since the water absorption rate was low, the contact angle of water drops on the coating after water absorption saturation was 13 °, which was a level that was not superhydrophilic, and the antifogging property was poor. As a result, it was unsuitable for use in a bathroom vanity or bathroom.

Claims (6)

In the antifogging mirror provided with a mirror body and a film in close contact with the mirror body, the film exhibits water absorption and hydrophilicity, and the contact angle of water droplets on the film is in a state where the film does not absorb water. An anti-fogging mirror characterized by having a water absorption rate of 15% by weight or more and 30% by weight or less when the water absorption is saturated at 40 ° or less. The antifogging mirror according to claim 1, wherein the film thickness is 5 µm or more and 30 µm or less. The antifogging mirror according to claim 1 or 2, wherein water absorption of the film is performed by oxyethylene chains present in the film. The antifogging mirror according to any one of claims 1 to 3, wherein the pencil hardness of the coating obtained in accordance with "JIS K 5400" is HB to F when the coating is saturated with water. Use of the anti-fog mirror according to any one of claims 1 to 4 for a vanity. Use of the anti-fog mirror according to any one of claims 1 to 4 in a bathroom.