JP2004244612A - Anti-fogging film, method for forming the same and anti-fogging film forming coating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-fogging film having high anti-fogging properties, and having excellent abrasion resistance, slipperiness, etc., to provide an anti-fogging film forming coating agent capable of forming the anti-fogging film, and to provide a method for forming the anti-fogging film. <P>SOLUTION: This anti-fogging film forming coating agent of two-pack curing type comprises a coating agent A which has an isocyanate component having isocyanate groups and a coating agent B which has a polyol component and a surfactant having isocyanate-reactive groups, wherein the polyol component has a water-absorbing polyol and a short-chain polyol having an average molecular weight of 60-200. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention can be used for various purposes such as anti-fog mirrors for bathrooms, lavatories, anti-fog window glasses or anti-fog mirrors for vehicles, architecture, lenses, displays, etc. The present invention relates to an anti-fogging film having excellent properties and the like, a coating agent for obtaining the anti-fogging film, and a forming method.

  Transparent substrates such as glass and plastic have a temperature / humidity difference between the inner surface and the outer surface across the substrate. In such a case (for example, when boiling steam comes into contact with the substrate, or when the environment moves from a low-temperature portion to a high-temperature and high-humidity environment), moisture in the atmosphere adheres as water droplets, and the surface of the substrate condenses. As a result, light scattering occurs due to the condensed water droplets. The occurrence of so-called "cloudiness" impairs the field of view, and significantly impairs the safety of general window glass, windshields of automobiles and aircraft, reflectors, glasses, sunglasses, and the like.

  As a method for preventing the occurrence of the "clouding", (1) a method in which a surfactant is applied to the surface of a base material to reduce a contact angle with water to form a water droplet into a water film (for example, Patent Document 1); 2) A solution in which a hydrophilic resin, a surfactant, and the like are mixed is applied to the surface of the base material, and the droplets are formed by heating or curing with ultraviolet light or an electron beam to reduce the contact angle with water, thereby forming a water film. (For example, Patent Document 2), (3) a method for forming a film having a photocatalyst on the surface of a substrate (for example, Patent Document 3), and (4) a hot-wire heater or an on-surface heater on the substrate surface (back surface). A method has been considered in which a substrate is heated by energizing an application heater to increase the temperature above the dew point (for example, Patent Document 4).

  However, the method (1) has a drawback that although the initial antifogging property is excellent, the surfactant flows out upon contact with water and the antifogging effect is short-lived. In the method (2), the antifogging function is not maintained for a long time due to the outflow of the surfactant from the film as in the method (1). The method (3) is advantageous in abrasion resistance because it is a film made of an inorganic substance, but requires ultraviolet light to exhibit antifogging properties, and does not necessarily exhibit antifogging properties in all environments. . The method (4) generally has a high cost, requires a long time for the substrate to warm up, requires time for the development of antifogging properties, and has problems such as thermal cracking. As described above, an antifogging film satisfying various durability such as sufficient antifogging property, antifogging durability and water resistance has not been obtained at present.

  In order to achieve both anti-fogging property and abrasion resistance, a coating agent for forming an anti-fogging film utilizing the hydrophilicity of a surfactant and the abrasion resistance due to the elasticity of a urethane resin has been studied. Patent Document 5 discloses a coating agent for forming an antifogging film in which a surfactant is contained in a three-dimensional crosslinked structure of a urethane resin. However, in the contents disclosed in this publication, the surfactant is merely carried in the three-dimensional crosslinked structure, and the surfactant flows out of the resin with the passage of time, so that the antifogging property is deteriorated.

  In Patent Document 6, by introducing a surfactant having a functional group that reacts with an isocyanate group into a two-pack curable resin composed of an isocyanate having an isocyanate group and a water-absorbing polyvinylpyrrolidone, the three-dimensional crosslinking of the resin is effected. A coating agent for forming an antifogging film having an active agent bound thereto is disclosed. Further, in Patent Document 7, by introducing a surfactant having a functional group which reacts with an isocyanate group into a two-pack curable resin of an isocyanate having an isocyanate group and a hydrophilic polyol, a three-dimensional crosslinking of the resin is achieved. A coating agent for forming an antifogging film having a surfactant bonded thereto is disclosed.

  The anti-fogging film formed from the coating agent for forming an anti-fogging film disclosed in each of the above-mentioned Patent Documents 6 and 7 has an anti-fogging film because the surfactant is bonded to the three-dimensional cross-linking of the elastic resin. It combines both clouding persistence and good abrasion resistance as compared to other resins.

However, even if it has good abrasion resistance compared to other resins, when an antifogging film is formed from these coating materials for forming antifogging films on window glasses and mirrors for construction and vehicles. However, there is a problem that the abrasion resistance is not yet sufficient, and it cannot withstand long-term use. In addition, very few examples have been studied for the smoothness of the anti-fogging film surface, that is, slip property, and the slip property of the film having anti-fogging property has been studied with a 20 μm to 30 μm sheet-like film. (For example, Patent Document 8).
JP-A-2-16185 JP 2001-040294 A Japanese Patent No. 2943768 JP-A-08-317841 JP-A-60-85939 Japanese Patent Publication No. Sho 61-502762 JP 2000-515572 A JP 2001-31806 A

  It is easily assumed that a variety of deposits adhere to the film surface during use and hinder the appearance and quality of the antifogging film.In order to remove those deposits, usually, a cloth or the like is used. Is performed. At this time, if the surface has insufficient slip properties, 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 adhered substance is rubbed against the film surface.If the slip property is poor, the adhered substance is likely to be caught on the film surface, causing many abrasions. Adverse effects such as sticking to the surface may occur.

  That is, when the slip property of the film is high, the abrasion resistance and antifouling property of the film are improved, and this is a very important index from a practical viewpoint. In order to improve the slip property of the film, it is common to introduce a silicone resin or the like into the film component.However, since the silicone resin is water repellent, the hydrophilicity of the film is impaired and the water absorption is impaired. Bring.

  An object of the present invention is to provide an antifogging film having high antifogging properties, excellent abrasion resistance and excellent slip properties, a method for forming the same, and a coating agent for forming an antifogging film.

  In order to solve the above-mentioned problems, the present invention has been made by diligently studying a coating agent for forming an antifogging film made of urethane resin. That is, the antifogging film-forming coating composition of the present invention comprises a coating composition A having an isocyanate component having an isocyanate group, a polyol component, and a coating composition B having a surfactant having an isocyanate-reactive group, The polyol component has a water-absorbing polyol and a short-chain polyol.

  The antifogging property of the antifogging film mainly depends on a surfactant having an isocyanate-reactive group such as a hydroxyl group, an amino group, or a mercapto group added to the coating agent B. By providing an isocyanate-reactive group to a surfactant that imparts a high water film-forming ability to the film, the surfactant binds to the crosslink of the urethane resin after the coating material is cured. Accordingly, since the surfactant is not eluted from the film, the durability of the antifogging film is improved and the antifogging property is maintained.

  The surfactant having an isocyanate-reactive group should be 10% by weight to 25% by weight based on the total amount of the isocyanate component, the surfactant having the isocyanate-reactive group, and the polyol component (hereinafter, the total amount of the urethane component). Is preferred. If the amount is less than 10% by weight, the effect on the anti-fogging property is small, and if it exceeds 25% by weight, the film strength is reduced. In consideration of the film strength, it is more preferable that the content of the surfactant is 20% by weight or less.

In order to make the antifogging film exhibit antifogging properties due to water absorption, the coating agent B may contain a polyoxyalkylene-based polyol having an oxyethylene chain having an average molecular weight of 400 to 5,000. As the oxyalkylene, a polyol having an oxyethylene chain, an oxypropylene chain, or the like can be used. Among these, the oxyethylene chain has a function of absorbing water as bound water, and enables the antifogging film to exhibit antifogging properties due to water absorption. In view of the water absorption and durability of the antifogging film, the oxyethylene unit [—CH ₂ CH ₂ O—] in the polyoxyalkylene may be 10% by weight to 25% by weight based on the total amount of the urethane component. preferable.

In consideration of the strength of the antifogging film, the polyoxyalkylene-based polyol can be contained in an amount of up to 40% by weight, preferably up to 30% by weight, based on the total amount of the urethane component.
When the average molecular weight of the polyoxyalkylene polyol is less than 400, the ability to absorb water as bound water is reduced, and when the average molecular weight is more than 5,000, poor curing of the coating agent or a decrease in film strength is caused. Failure is likely to occur. The average molecular weight is more preferably 400 to 4500 in consideration of water absorption and film strength.

  The slip properties of the antifogging film are achieved with short-chain polyols having an average molecular weight of 60 to 200. The short-chain polyol is a component necessary for imparting a surface slip property without impairing the anti-fogging property of the film. When the average molecular weight of the short-chain polyol is less than 60, the coating agent becomes unstable, and when the average molecular weight exceeds 200, the curability of the formed film is deteriorated.

  As the short-chain polyol, a bifunctional or higher-functional alkanolamine or an alkyl polyol can be used. The short-chain polyol is preferably bifunctional or more, and in the case of monofunctional, the slip property of the film is inhibited.

  Such a short-chain polyol is preferably used in an amount of 4% by weight to 14% by weight based on the total amount of the urethane component. If the amount is less than 4% by weight, there is almost no slipping effect. If the amount is more than 14% by weight, problems such as deterioration of the antifogging property of the film due to excessive curing of the coating agent and deterioration of the stability of the coating agent occur. .

  The antifogging film of the present invention can be formed on a substrate from the above coating agent, and is a urethane resin film having a static friction coefficient of a film surface of 0.8 or less measured according to “JIS K 5400”. is there. A water-absorbing component derived from a water-absorbing polyol, a surfactant bonded to a urethane resin crosslink, and a component imparting slip properties derived from a short-chain polyol are appropriately contained to obtain an antifogging film excellent in various properties. be able to.

  The anti-fog film excellent in the above various properties is obtained by mixing at least a polyol component and a surfactant having an isocyanate-reactive group to obtain a coating agent B having a polyol component and a surfactant having an isocyanate-reactive group. Adding a coating agent A having an isocyanate component having an isocyanate group to the agent to obtain a coating agent for forming an antifogging film, applying the coating agent for forming an antifogging film on a substrate surface, The coating is hardened by leaving it alone or by heat treatment up to 170 ° C., preferably 80 ° C. or more.

  The antifogging film formed from the coating agent for forming an antifogging film of the present invention has excellent antifogging properties, excellent abrasion resistance, excellent slip properties, etc. It can be used in such places.

The coating agent for forming an antifogging film of the present invention is a coating agent for forming an antifogging film for forming an antifogging film on a substrate, wherein the coating agent for forming an antifogging film is a urethane resin. It is a two-part curable coating agent comprising a coating agent A having an isocyanate component having an isocyanate group, a polyol component, and a coating agent B having a surfactant having an isocyanate-reactive group.
As the isocyanate component, a difunctional isocyanate, preferably a 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.

  The ratio of the number of isocyanate groups present in the isocyanate component to the number of hydroxyl groups and mercapto groups and amino groups present in the polyol component and the surfactant in the coating agent B is preferably 0.8 to 2, preferably Is preferably adjusted to be 0.9 to 1.6, more preferably 1.0 to 1.3. When the ratio is less than 0.8, the curability of the coating agent is deteriorated, and the formed film has a problem that the unreacted surfactant is eluted on the film surface, giving a feeling of stickiness of the film. On the other hand, when it exceeds 2, the anti-fogging property decreases due to excessive curing.

  A surfactant is a component that imparts hydrophilicity to a film formed from a coating agent to exhibit anti-fogging properties, and has a functional group that reacts with and binds to an isocyanate group such as a hydroxyl group, a mercapto group, or an amino group. As the surfactant, cationic, anionic, zwitterionic and nonionic surfactants can be used.

  As anionic surfactants having an isocyanate-reactive group, 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 glycerin ether monosulfate, polyoxyalkylene glycerin ether mono Phosphor Etc. The.

  Examples of the cationic surfactant having an isocyanate-reactive group include dialkanolamine salts, trialkanolamine salts, polyoxyalkylenealkylamine ether salts, fatty acid trialkanolamine ester salts, polyoxyalkylenedialkanolamine ether salts, and polyoxyalkylenedialkanolamine ether salts. Alkylene trialkanolamine ether salt, di (polyoxyalkylene) alkylbenzylalkylammonium salt, alkylcarbamoylmethyldi (polyoxyalkylene) ammonium salt, polyoxyalkylenealkylammonium salt, polyoxyalkylenedialkylammonium salt, ricinoleamidopropylethyl And dimonium ethosulfate.

  Examples of the amphoteric surfactant having an isocyanate-reactive group include N, N-di (β-hydroxyalkyl) N-hydroxyethyl-N-carboxyalkylammonium betaine and N-β-hydroxyalkyl-N, N-diamine. Polyoxyalkylene-N-carboxyalkylammonium betaine, monoester of N-alkyl-N, N-di (polyoxyalkylene) amine and dicarboxylic acid, N- (polyoxyethylene) -N ', N'-di (poly (Oxyethylene) aminoalkyl-N-alkyl-N-sulfoalkylammonium betaine, N, N-di (polyoxyethylene) -N-alkyl-N-sulfoalkylammonium betaine, N- (β-hydroxyalkylaminoethyl)- N- (β-hydroxyalkyl) aminoethylcarboxylic acid, N, '-Bis (2-hydroxyalkyl) -N, N'-bis (carboxyethyl) ethylenediamine salt, N- (β-hydroxyalkyl) -N', N'-di (polyoxyethylene) -N-carboxyethylethylenediamine And the like.

  Examples of the nonionic surfactant having an isocyanate-reactive group include polyoxyethylene polyoxypropylene block polymer, sorbitol fatty acid ester, sorbitan fatty acid ester, shotang fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, fatty acid monoglyceride, and polyoxyalkylene. Fatty acid monoglyceride, polyglycerin fatty acid ester, polyoxyalkylene castor oil ether, polyoxyalkylene alkylamine polyoxyalkylene alkylamide, and the like.

  As the surfactant having an isocyanate-reactive group, one or more of the surfactants described above can be used.

  The water-absorbing polyol added to the coating agent B may contain a water-absorbing polyoxyalkylene-based polyol having an average molecular weight of 400 to 5000, preferably 400 to 4500. As the water-absorbing polyol that can be used in the present invention, polyethylene glycol, polypropylene glycol, oxyethylene / oxypropylene copolymer polyol, and the like can be used. When using polyethylene glycol, particularly when using a single type, The average molecular weight is preferably from 400 to 2,000. If it is less than 400, the ability to absorb water is small, and if it is more than 2,000, curing of the coating agent is hindered, and the formed film is very fragile.

  Further, the short-chain polyol introduced for imparting a slip property to the antifogging film also has a role of enhancing the curability of the coating agent and increasing the strength of the antifogging film. The number of hydroxyl groups of the short-chain polyol is preferably 2 or 3. When the number of hydroxyl groups is 1, the film becomes brittle because the short-chain polyol does not become a skeleton component of the film. When the number of hydroxyl groups 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-ethyl-2- (hydroxymethyl) -1,3-propanediol, 1,2,6-hexanetriol, 2, Examples thereof include alkyl polyols such as 2'-thiodiethanol, and alkanolamines such as diethanolamine and triethanolamine. These can be used alone or as a mixture, or a copolymer having an average molecular weight of not more than 200 can be used.

  Generally, when a component that improves the durability of the film, such as a short-chain polyol, is introduced, the antifogging property of the antifogging film decreases. However, by containing an appropriate amount of a surfactant having an isocyanate-reactive group and an appropriate amount of a water-absorbing polyol, an antifogging film having excellent antifogging properties, water resistance, abrasion resistance, etc. is obtained. be able to.

  In order to further improve the abrasion resistance of the antifogging film, a precursor of a metal oxide and a silane coupling agent can be added to the coating material B. As the precursor of the metal oxide, alkoxide compounds such as ethoxide compounds and methoxide compounds, oxyhalogen compounds, acetyl compounds and the like can be used. Further, as the metal oxide, one or more selected from silica, titania, zirconia, alumina, niobium oxide, and tantalum oxide can be used, and silica is particularly preferable from an economic viewpoint. The metal oxide precursor can be added up to 1.25 times the weight of the total urethane component. If the amount exceeds 1.25 times, the anti-fogging property of the obtained film is reduced. From the viewpoint of improving abrasion resistance, the metal oxide precursor is preferably added up to 0.1 times the weight of the total amount of the urethane component.

  The silane coupling agent can be added up to 0.25 times the weight of the total amount of the urethane component. If the amount is more than 0.25 times, the strength of the film obtained due to the unreacted functional group of the silane coupling agent decreases, and at the same time, the film surface becomes sticky. Further, from the viewpoint of crosslinking the metal oxide and the urethane resin, it is preferable that the silane coupling agent is added in an amount of 0.01 times by weight based on the total amount of the urethane component. It is particularly preferable that the silane coupling agent is 3-methacryloxypropyltrimethoxysilane or 3-glycidoxypropyltrimethoxysilane because a uniform film can be obtained.

  In order to improve the abrasion resistance of the anti-fogging film, the coating agent A and / or the coating agent B may be made of a metal oxide such as silica, titania, zirconia, alumina, niobium oxide, or tantalum oxide having an average particle size of 5 to 50 nm. Fine particles can be contained, and it is particularly preferable to contain colloidal silica. When the metal oxide fine particles are contained, it is important that the anti-fogging property of the anti-fogging film is not reduced. Therefore, the content is 40% by weight or less, preferably 20% by weight, based on the total amount of the urethane component. %, More preferably 10% by weight or less. Incidentally, the average particle size referred to here is a value obtained by visually observing the particle size of all the particles present in a range of 1 μm square when the cross section of the film is observed at a magnification of 100,000 by scanning electron microscope observation. , And calculate the average value. This calculation is defined as an average value of each value obtained by repeating the calculation 20 times.

  After mixing a polyol component and a surfactant having an isocyanate-reactive group, in a step of adding and mixing an isocyanate component having an isocyanate group to obtain a coating agent, the isocyanate group reacts with a hydroxyl group, a mercapto group, and an amino group to form urethane. Bonding occurs and urethane resin begins to form.

  Each of the raw materials for forming the antifogging film-forming coating agent or the prepared antifogging film-forming coating agent can be added to a diluting solvent. The diluting solvent must be a solvent having no activity with respect to the isocyanate group, and is based on the compatibility of each forming material of the antifogging film forming coating material or the prepared antifogging film forming coating agent. , Methylpropylene glycol and diacetone alcohol are preferred.

  Next, a coating agent for forming an antifogging film is applied to the substrate. Known means such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, and flexographic printing can be used as the application means. After the application, the coating material for forming an anti-fogging film is cured by being left at room temperature of about 20 ° C. or by heat treatment up to 170 ° C. to form an anti-fogging film on the substrate. If the temperature of the heat treatment exceeds 170 ° C., carbonization of the urethane resin occurs, causing problems such as a decrease in film strength. In order to accelerate the curing reaction of the coating agent, it is more preferable to perform the heat treatment at 80C to 170C.

  The film thickness of the anti-fogging film is desirably about 5 μm to 40 μm after the curing reaction of the coating agent for forming the anti-fogging film. If it is less than 5 μm, the durability tends to be inferior. If it exceeds 40 μm, inconveniences such as occurrence of optical distortion in appearance quality are likely to occur.

  As a substrate to which the coating agent for forming an antifogging film of the present invention is applied, glass is typically used. The glass is a plate glass generally used for automobiles, architectural glass, industrial glass, and the like, and is a plate glass obtained by a float method, a duplex method, a roll-out method, etc., and its production method is not particularly limited. As a glass type, it can be used for various colored glasses such as clear and green, bronze and the like, and various functional glasses such as UV, IR cut glass and electromagnetic shielding glass, netted glass, low expansion glass, fire resistant glass such as zero expansion glass. Various kinds of glass products such as glass, tempered glass, similar glasses, laminated glass, double-layer glass, mirrors manufactured by a silver drawing method or a vacuum film forming method, and flat plates and bent plates can be used. The plate thickness is not particularly limited, but is preferably 1.0 mm or more and 10 mm or less, and is preferably 1.0 mm or more and 5.0 mm or less for vehicles. The formation of the antifogging film on the substrate may be performed on only one side of the substrate or on both sides. The formation of the anti-fogging film may be on the entire surface of the substrate or on a part thereof.

  In addition, the substrate on which the coating agent for forming an anti-fogging film of the present invention is applied is not limited to glass, but may be a resin film such as polyethylene terephthalate, a resin such as polycarbonate, a metal (particularly a metal mirror), Ceramics and the like can also be used.

  The antifogging film-forming coating composition of the present invention may be used as an indoor mirror, a bathroom, a mirror for a washroom, a window glass, a vehicle, a ship, an aircraft, etc. Or, mirrors, specifically, room mirrors, door mirrors, etc., as well as lenses, such as glasses and cameras, goggles, helmet shields, refrigerated showcases, frozen showcases, testing machines, precision instrument cases, etc. Examples include windows, road reflectors, and displays of mobile communication bodies such as mobile phones. Since the antifogging film of the present invention has excellent slip properties, it is difficult for contaminants and the like to adhere to the film surface, and even when contaminants and the like adhere, it can be easily removed by wiping work or the like. It has high abrasion resistance and antifouling properties, and is particularly effective for the above-mentioned applications.

  Hereinafter, the present invention will be specifically described with reference to examples.

  The quality of the antifogging films obtained in the examples and comparative examples was evaluated by the following method.

  [Appearance evaluation]: The appearance, permeability, and the presence or absence of cracks of the anti-fogging film were visually evaluated. Those having no problem were evaluated as acceptable (O), and those having problems were evaluated as failed (X).

  [Repeated anti-fogging property]: The degree of fogging when kept in steam of warm water set at 43 ° C. for 3 minutes in accordance with “JIS S 4030 Eyeglass Antifogging Agent Test Method”, and at room temperature (23 ° C.) , Humidity 63%). This operation was performed as one cycle for 10 cycles, and a film having no abnormality in appearance and no fogging was evaluated as pass (合格), and a film with fogging was evaluated as rejected (x).

  [Low-temperature anti-fogging property]: After keeping in a freezer set at 4 ° C. for 30 minutes, the appearance, the degree of fogging, and the fogging due to exhalation are observed when taken out at room temperature (23 ° C., 63% humidity). This operation was performed as one cycle for 10 cycles, and the film having no abnormality in appearance and causing no fogging was evaluated as pass (合格), and the film with fogging was evaluated as failed (x).

[Traverse abrasion resistance]: The appearance and exhalation antifogging property when a flannel (cotton No. 300) was reciprocated 5000 times with a load of 4.9 N / 4 cm ² on the film surface were measured, and those without abnormalities were passed (O). Those with abnormalities were rejected (x).

  [Pencil hardness]: In accordance with "JIS K 5400 paint general test method", the surface of the film was scratched five times with a pencil to which a load of 1 kg was added, and the pencil having less than two breaks in the film was regarded as the pencil hardness. .

[Slip property]: A square sliding piece with a contact area of 40 cm ² (length of one side of 63 mm) was applied on a fogging-preventing film at a load of 200 g in accordance with “JIS K 7125 Plastic-film and sheet-Friction coefficient test method”. And the slip property was measured. In addition, the bottom surface of the sliding piece (the ground contact surface with the specimen) was covered with a flannel (cotton No. 300) assuming wiping in actual use.

  Here, those having a static friction coefficient of 0.8 or less derived from the measured values were evaluated as acceptable (（), and those exceeding 0.8 were evaluated as unacceptable (x). The lower the coefficient of static friction, the better the durability of the film by imparting the slip property is preferable. However, from the viewpoint of compatibility with the anti-fogging property, it can be actually used in the range of 0.4 to 0.8. .

Example 1
(Preparation of coating agent for forming antifogging film)
17.5 g of ricinoleamidopropylethyldimonium ethosulfate (trade name “Lipoquat®” manufactured by Lipo chemicals Inc) as a surfactant having an isocyanate-reactive group, 8.7 g of triethanolamine as a short-chain polyol, A coating agent B was prepared by mixing 20 g of polyethylene glycol having an average molecular weight of 1,000 as a water-absorbing polyol. A burette type polyisocyanate of xamethylene diisocyanate (trade name "N3200", manufactured by Sumitomo Bayer Urethane) as an isocyanate component was applied in an amount of 53.8 g so that the ratio of isocyanate groups / isocyanate-reactive groups became 1.2. After adding and mixing the agent A, antifogging is performed by adding diacetone alcohol as a diluting solvent so that the concentration of the total amount of the urethane component (the total amount of the urethane component becomes 100 g in this example) becomes 35% by weight. A coating agent for forming a conductive film was prepared.

(Formation of anti-fogging film)
This coating agent is applied as a coating agent onto a glass substrate manufactured by a float method with a size of 1000 mm × 1000 mm × 3 mm (thickness) by spin coating, and the coated glass plate is heated and dried at about 150 ° C. for about 30 minutes. As a result, an antifogging film having a thickness of 28 μm was formed.

  The glass having an antifogging film obtained by the above method has a static friction coefficient of 0.73 obtained in the above evaluation of the slip property, and as shown in Table 1, the glass has an antifogging property, abrasion resistance and the like. It was confirmed that the durability was excellent.

Example 2
An antifogging film was obtained in the same manner as in Example 1 except that the amount of the surfactant having an isocyanate-reactive group was 10 g, the amount of the short-chain polyol was 10.6 g, and the amount of the isocyanate component was 59.4 g. In the examples, the total amount of the urethane component is 100 g). The obtained anti-fogging film had a thickness of 30 μm and a static friction coefficient of 0.67 obtained by the above-mentioned evaluation of the slip property. As shown in Table 1, the anti-fogging property, durability such as abrasion resistance, etc. It was confirmed that the properties were excellent.

Example 3
An antifogging film was obtained in the same manner as in Example 1 except that the amount of the short-chain polyol was 11.3 g, the amount of the water-absorbing polyol was 10 g, and the amount of the isocyanate component was 61.2 g (urethane in this example). The total amount of the components is 100 g). The obtained anti-fogging film has a thickness of 30 μm, a static friction coefficient of 0.58 obtained by the evaluation of the above-mentioned slip property, and a durability such as anti-fogging property and abrasion resistance as shown in Table 1. It was confirmed that the properties were excellent.

Example 4
An antifogging film was obtained in the same manner as in Example 1, except that the amount of the short-chain polyol was 6 g and the amount of the isocyanate component was 56.5 g so that the ratio of the isocyanate group / isocyanate-reactive group was 1.6. (In this example, the total amount of the urethane component is 100 g). The obtained anti-fogging film has a thickness of 28 μm, a coefficient of static friction obtained by the above-mentioned evaluation of the slip property of 0.78, and as shown in Table 1, durability such as anti-fogging performance and abrasion resistance. It was confirmed that the properties were excellent.

Example 5
An antifogging film was obtained in the same manner as in Example 1 except that diethanolamine was used as the short-chain polyol in an amount of 9.1 g and the isocyanate component was used in an amount of 53.4 g (in this example, the total amount of the urethane component was 100 g. And). The obtained anti-fogging film had a thickness of 25 μm, a static friction coefficient of 0.70 obtained by the evaluation of the above-mentioned slip property, and as shown in Table 1, durability such as anti-fogging performance and abrasion resistance. It was confirmed that the properties were excellent.

Example 6
An antifogging film was obtained in the same manner as in Example 1 except that the amount of 1,4-butanediol was 8 g as the short-chain polyol and the amount of the isocyanate component was 54.5 g (in this example, the total amount of the urethane component was Is 100 g). The obtained anti-fogging film had a thickness of 32 μm and a static friction coefficient of 0.78 obtained in the above evaluation of the slip property. As shown in Table 1, the anti-fogging property, durability such as abrasion resistance, etc. It was confirmed that the properties were excellent.

Example 7
The same procedure as in Example 1 was repeated except that the amount of the surfactant was 25 g, the amount of the short-chain polyol was 5.7 g of diethylene glycol, the amount of the water-absorbing polyol was 25 g, and the amount of the isocyanate component was 44.3 g. (In this example, the total amount of the urethane component was 100 g). The obtained anti-fogging film had a thickness of 30 μm, a coefficient of static friction obtained by the above-mentioned evaluation of slip property of 0.75, and as shown in Table 1, durability such as anti-fogging performance and abrasion resistance. It was confirmed that the properties were excellent.

Comparative Example 1
The antifogging film was prepared in the same manner as in Example 1, except that the amount of the surfactant was 35.2 g, the amount of the water-absorbing polyol was 35.2 g, and the amount of the isocyanate component was 29.6 g without adding the short-chain polyol. (In this example, the total amount of the urethane component was 100 g). The obtained antifogging film has a film thickness of 24 μm, a coefficient of static friction obtained in the above evaluation of slip property of 1.9, poor curability, stickiness, poor slip property, and traverse. In the abrasion test, scratches occurred.

Comparative Example 2
An antifogging film was obtained in the same manner as in Example 1 except that the amount of the short-chain polyol was 10.2 g of monoethanolamine and 52.3 g of the isocyanate component (in this example, the total amount of the urethane component was 100 g). And the amount). The obtained antifogging film has a thickness of 36 μm, a coefficient of static friction obtained by the above evaluation of the slip property of 1.73, has poor curability, has a sticky feeling, deteriorates the slip property, and traverses. In the abrasion test, scratches occurred.

Comparative Example 3
Antifogging was performed in the same manner as in Example 1 except that the amount of the surfactant was 23.2 g, the amount of the short-chain polyol was 12.5 g of triethanolamine, and the amount of the isocyanate component was 64.3 g without adding the water-absorbing polyol. A functional film was obtained (in this example, the total amount of the urethane component was 100 g). The resulting anti-fogging film had a thickness of 30 μm and a good static friction coefficient of 0.60 obtained by the above-mentioned evaluation of the slip property, and the slip property was good. Clouding has occurred.

Comparative Example 4
Example 1 Example 1 was repeated except that the amount of the surfactant was 25 g, the amount of the short-chain polyol was 13.8 g of polypropylene glycol, which was a polyol having an average molecular weight of 400, the amount of the water-absorbing polyol was 25 g, and the amount of the isocyanate component was 36.2 g. An anti-fogging film was obtained by the same operation as in Example 1 (in this example, the total amount of the urethane component was 100 g). The obtained antifogging film has a thickness of 33 μm, a static friction coefficient of 1.1 obtained in the above evaluation of the slip property, poor curability, stickiness, poor slip property, and traverse. In the abrasion test, scratches occurred.

Comparative Example 5
An antifogging film was obtained in the same manner as in Example 1 except that the amount of the short-chain polyol was 13.44 g and the amount of the isocyanate component was 66.8 g without adding a surfactant having an isocyanate-reactive group. In the examples, the total amount of the urethane component is 100 g). The obtained antifogging film had a thickness of 28 μm and a good static friction coefficient of 0.80 as obtained in the above evaluation of the slipping property, and the slipping property was good. Clouding has occurred.

Comparative Example 6
A coating agent B was prepared by mixing 17.5 g of ricinoleamidopropylethyldimonium ethosulfate as a surfactant having an isocyanate-reactive group and 20 g of polyethylene glycol having an average molecular weight of 1000 as a water-absorbing polyol. did. A coating agent A was added to the burette type polyisocyanate of hexamethylene diisocyanate in an amount of 15.9 g so that the ratio of the isocyanate group / isocyanate reactive group became 1.2, and the mixture was mixed with the urethane component. %, Diacetone alcohol was added as a diluting solvent. Then, instead of the short-chain polyol, polyether-modified silicone (trade name “L-7607N” manufactured by Nippon Unicar) was added in the same manner as in Example 1, except that 0.05% was added to the mixed coating agent. A cloudy film was obtained. The obtained antifogging film had a film thickness of 24 μm, a static friction coefficient of 0.62 obtained in the above evaluation of slip properties, and good slip properties. Clouded.

Claims (7)

A two-part curable antifogging film-forming coating agent, comprising: coating agent A having an isocyanate component having an isocyanate group, coating agent B having a polyol component and a surfactant having an isocyanate-reactive group. Wherein the polyol component comprises a water-absorbing polyol and a short-chain polyol having an average molecular weight of 60 to 200 and 2 or 3 hydroxyl groups. The antifogging film according to claim 1, wherein the short-chain polyol is contained in an amount of 4% by weight to 14% by weight based on the total amount of the isocyanate component, the polyol component, and the surfactant having an isocyanate-reactive group. Forming agent. The coating agent for forming an antifogging film according to claim 1 or 2, wherein the short-chain polyol is a bifunctional or higher-functional alkanolamine or alkyl polyol. The water-absorbing polyol is a polyoxyalkylene-based polyol having an average molecular weight of 400 to 5,000, and the oxyethylene unit [—CH ₂ CH ₂ O—] in the polyoxyalkylene includes an isocyanate component, a polyol component, and an isocyanate-reactive group. The coating agent for forming an antifogging film according to any one of claims 1 to 3, wherein the coating amount is 10% by weight to 25% by weight based on the total amount of the surfactant having The surfactant having an isocyanate-reactive group is 10% by weight to 25% by weight based on the total amount of an isocyanate component, a polyol component, and a surfactant having an isocyanate-reactive group. The coating agent for forming an anti-fogging film according to any one of claims 1 to 5. A urethane resin film having a coefficient of static friction of a film surface of 0.8 or less measured in accordance with “JIS K 5400” and having a water-absorbing component derived from a water-absorbing polyol, and a surfactant bonded to a cross-linked urethane resin. An anti-fogging film characterized by the following. A polyol component and a surfactant having an isocyanate-reactive group are mixed to obtain a coating agent B having a polyol component and a surfactant having an isocyanate-reactive group, and a coating agent having an isocyanate component having an isocyanate group in the coating agent Adding and mixing A to obtain a coating agent for forming an anti-fogging film, applying the coating agent for forming an anti-fogging film on the surface of a base material, curing the coating agent by leaving it at room temperature or by heat treatment up to 170 ° C. The method for forming an anti-fogging film according to claim 6, wherein the step of forming the anti-fogging film on the substrate is performed by the step of performing the step of forming.