JP2013158990A - Antifogging article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antifogging coating which is more useful than the conventionally accepted and shows antifogging properties, satisfactory adhesion with a base and film hardness.SOLUTION: An antifogging coating formed on a transparent base is made of a urethane resin. The urethane resin is characterized in that this resin can be obtained through a chemical reaction of at least the following three components: (a) an acryl polyol with a number-average molecular weight of 6,000 to 18,000, (b) a polyoxyalkylene-based polyol with a number-average molecular weight of 400 to 5,000 and (c) an isocyanate prepolymer.

Description

  The present invention relates to an antifogging film made of a urethane resin, which is obtained by applying a coating agent on a transparent substrate and has water absorption performance.

  Transparent substrates such as glass are used for building window materials, vehicle window materials, and the like.

  When a transparent base material such as glass is placed in a highly humid place or moved to a place where there is a temperature difference or humidity difference, if the dew point is exceeded, the surface will dew and become cloudy. For example, when a vehicle is driven during a rainy season with high humidity, during low temperatures in winter, or when several people are in the vehicle, the windows are likely to be cloudy. It is usually done. Further, when the door of a large freezer is opened, the inside of the viewing window provided on the door may be condensed due to a temperature difference between the inside and outside of the freezer and may become cloudy, and visibility may not be ensured.

  In automobiles, in order to ensure the visibility of windows, the load of operating the air conditioner used to remove fog is large, and for example, it has been a foothold for improving the fuel efficiency of cars. In particular, the load of operating the air conditioner is large in winter when the temperature difference between indoor and outdoor is intense, especially in cold regions. Providing anti-fogging articles such as window glass that can reduce these problems is indispensable for improving fuel efficiency. The need for anti-fogging glass is expected to increase in the future for hybrid vehicles that use both motors and engines, and electric vehicles that use fuel cells.

  Also, when the door of a large freezer is opened, the inside of the sight glass provided on the door does not condense and the visibility is not secured.On the other hand, if the fog is removed by the heat of the heater attached to the sight glass, This leads to an increase in temperature and cost of electricity. Therefore, development of an excellent anti-fogging window material is awaited.

  The antifogging window material is obtained by forming a hydrophilic and water-absorbing thin film on a transparent base material to provide antifogging performance, and this thin film is called an antifogging coating.

  Patent Document 1 discloses a vehicle antifogging glass obtained by applying a composition containing an organic antifogging material to an ultraviolet ray low-transmitting glass. Patent Document 2 discloses a vehicle window glass in which a hydrophilic layer having a contact angle with water containing alumina on an indoor surface is 30 ° or less.

JP 2000-239045 A JP2003-321251A JP 2007-076999 A JP 2009-242219 A

  Patent Document 1 discloses the use of a silica fine particle-based porous film and a water-absorbing resin as those that exhibit anti-fogging properties due to water absorption, but the water absorption capability of these water-absorbing films is not sufficient. Further improvement was necessary for the development of anti-fogging properties due to water absorption. In addition, since it has not been designed from the viewpoint of developing anti-fogging properties in a sub-freezing environment, it is expected that defects such as a decrease in translucency due to freezing of absorbed water and destruction of the film may occur. .

  In a design in which continuous antifogging is expressed with the hydrophilicity of the film, a water film is formed on the film at any time when the antifogging is exhibited. Therefore, since a problem such as an image that appears through the water film appears in the end, such a problem may occur when the antifogging property is exhibited for a long time, for example, when the vehicle is operated for a long time in a cold region.

  The present applicant solves the above problems, and is a coating derived from a urethane resin derived from an acrylic polyol and a polyoxyalkylene polyol, and the coating exhibits antifogging properties by absorbing water. Patent Document 3 discloses an anti-fogging film that is used in an indoor environment having a mechanism for forcibly dehydrating from a film after water absorption is saturated, and does not form a water film when the anti-fogging property is exhibited. doing. In Patent Document 4, an anti-fogging film made of a water-absorbing urethane resin polymerized using a hydrophobic polyol and a polyoxyalkylene polyol has a multiple glass structure in which a plurality of glass plates face each other. The method of ensuring the visual field of a glass window by forming in the side exposed to the cold / warm environment of the glass window which it has is disclosed. These antifogging coatings were effective coatings having excellent antifogging properties, but there was room for further performance improvement.

  In view of the above, an object of the present invention is to provide an antifogging film having more useful antifogging properties, adhesion to a substrate, and film hardness.

  The coating film had good water absorption and effective anti-fogging properties, but the present inventors further studied and acrylic polyol which is one of the components forming the skeleton of the coating film. It was found that by using a material having a higher number average molecular weight, a sufficient amount of water absorption can be maintained, a good antifogging film having excellent adhesion to the base material and excellent film hardness can be obtained. .

That is, the present invention is an antifogging film formed on a transparent substrate, and the film is made of a urethane resin, and the urethane resin has at least the following three components a) Number average molecular weight is 6000 to 18000. Acrylic polyol b) Polyoxyalkylene polyol having a number average molecular weight of 400 to 5000 c) A resin obtained by reaction of an isocyanate prepolymer.

  Moreover, it is preferable that it is an anti-fogging film whose hydroxyl value of the said acrylic polyol is 20-60 mgKOH / g. The hydroxyl value is calculated by the following formula (wherein “OHV” represents the hydroxyl value and “% OH” represents the hydroxyl group content of the compound).

OHV [mg KOH / g] = 33 ×% OH
Moreover, it is preferable that mass ratio of the said acrylic polyol and the said polyoxyalkylene type polyol exists in the range of acrylic polyol: polyoxyalkylene type polyol = 30: 70-70: 30.

Moreover, it is preferable that a linear polydimethylsiloxane component having 5 to 300 dimethylsiloxane units (Si (CH ₃ ) ₂ O) as a crosslinking unit is further introduced into the urethane resin.

  Moreover, this invention is an anti-fogging window material which consists of said film and a transparent base material.

  The present invention also provides a coating agent for forming the above antifogging film, which is a drug A containing at least the acrylic polyol and the polyoxyalkylene polyol, and a drug B containing at least the isocyanate prepolymer. Is a coating agent for forming an antifogging film obtained by mixing the above.

  The present invention also provides a method for producing the above antifogging window material, comprising mixing at least the acrylic polyol and the drug A containing the polyoxyalkylene polyol and the drug B containing at least the isocyanate prepolymer. The coating agent for forming an antifogging film obtained by applying is applied to the surface of a transparent substrate, and the substrate is left at room temperature or subjected to heat treatment.

  The anti-fogging film is a film capable of reversibly absorbing and dehydrating, has a good water absorption function, prevents fogging and condensation, and forcibly absorbs moisture absorbed in the film even after water absorption is saturated. It is possible to maintain the antifogging property by using a dewatering mechanism.

  Here, the mechanism for forcibly dehydrating the antifogging film after water saturation is a mechanism that can bring the surrounding environment of the film from a cloudy environment to an environment that is not cloudy. An air conditioner having an air blowing function, a temperature adjusting function, or the like corresponds to the mechanism.

  When an acrylic polyol having a high number average molecular weight is used, the number of moles present is reduced compared to the case of using the same amount of a low molecular weight, and therefore, an isocyanate prepolymer, which is another component that forms the skeleton of the coating, Therefore, it is presumed that the polyoxyalkylene polyol, which is a water-absorbing component, reacts more and can impart excellent antifogging properties to the resulting film.

  The anti-fogging coating of the present invention is excellent in anti-fogging properties such as preventing fogging even in a sub-freezing environment, and therefore maintains optical properties such as translucency of articles in a cloudy environment. And even after the water absorption of the film is saturated, when used together with a mechanism for forced dehydration from the film, the water can be quickly dehydrated and the film can be absorbed again, that is, the antifogging property is developed. It can be. Furthermore, the coating film is highly useful because it has excellent adhesion to the substrate and excellent film hardness. Therefore, when the anti-fogging article formed with the anti-fogging coating of the present invention is used as a window, it is easy to ensure visibility, and when used as an automobile window, the safety of the automobile is improved and the fuel efficiency is improved. To be successful. In addition, when used on a large refrigerator door with a viewing window, a heater for removing the fogging of the viewing window when the door is opened is unnecessary, which increases the temperature inside the cabinet and increases the cost of electricity bills. Can be prevented.

  First, each of the three components forming the antifogging film, which is a feature of the present invention, will be described.

  The acrylic polyol mainly causes the coating film to lower the wear resistance, water resistance, and surface friction coefficient, that is, to exhibit the slip property on the film surface. Moreover, it is also effective in shortening the leveling process which equalizes the film thickness deviation at the time of apply | coating the coating agent for film formation to a base material.

  In the present invention, the acrylic polyol has a number average molecular weight of 6,000 to 18,000. Preferably it is 8000-16000, More preferably, it is 12000-16000.

When the number average molecular weight of the acrylic polyol is smaller than 6000, the film becomes too dense and easily fragile. On the other hand, if it is larger than 18000, the wear resistance is reduced due to the loss of the denseness of the film.

  Furthermore, it is also preferable that the hydroxyl value of the acrylic polyol is in the range of 20 to 60 mgKOH / g. When the hydroxyl value of the acrylic polyol is less than 20 mgKOH / g, the amount of reaction with the isocyanate prepolymer is reduced, so that the strength of the film cannot be ensured, and the wear resistance is also lowered due to a decrease in denseness. On the other hand, if it exceeds 60 mgKOH / g, the film density will be improved, but many hydroxyl groups will be present in the acrylic polyol, and the reactive group of the isocyanate prepolymer will be used for the reaction with the acrylic polyol, resulting in water absorption. The polyoxyalkylene polyol which is a component to be exhibited is not sufficiently retained in the obtained film, and the target antifogging property cannot be obtained. By setting the hydroxyl value of the acrylic polyol within this range, an improvement in film hardness due to an appropriate film density and a high water absorption ability of the film can be obtained. As such a hydroxyl value acrylic polyol, as a commercially available product, for example, ACRYDIC DU-1446-X (manufactured by DIC Corporation) is easily available and preferable.

  The polyoxyalkylene polyol mainly causes the film to exhibit a water-absorbing function when it becomes a film (hereinafter also referred to as “water-absorbing component”). As this polyol, a polyol having an oxyethylene chain, an oxypropylene chain, or the like can be used. In particular, the oxyethylene chain is excellent in the function of absorbing water as bound water, which is advantageous in achieving an antifogging coating film that exhibits reversible absorption and dehydration with a high dehydration rate during dehydration. Thus, it is preferable to use a polyol having an oxyethylene chain in consideration of antifogging properties in a low temperature environment such as winter when the ambient temperature is 5 ° C. or lower.

  The number average molecular weight of the polyoxyalkylene-based polyol is usually 400 to 5000, and when the number average molecular weight is less than 400, the ability to absorb water as bound water is low, and when the number average molecular weight exceeds 5000, Problems such as poor curing of the coating agent and a decrease in film strength are likely to occur. Considering the water absorption and film strength of the coating, the number average molecular weight is more preferably 400-4500.

  In particular, when the polyoxyalkylene-based polyol is polyethylene glycol, the number average molecular weight is preferably set to 400 to 2000 in consideration of the ability to absorb water, poor curing, and film strength. In the case of an oxyethylene / oxypropylene copolymer polyol, the number average molecular weight is preferably 1500 to 5000.

  A plurality of types of polyols may be used as the polyoxyalkylene-based polyol. In this case, it is preferable to use polyethylene glycol having a number average molecular weight of 400 to 2000 as at least one type. Since the polyol is particularly excellent in the ability to absorb water as bound water, any polyoxyalkylene polyol may be used as the polyol.

As the isocyanate prepolymer, a bifunctional and / or trifunctional polyisocyanate having an isocyanurate structure using diisocyanate, preferably hexamethylene diisocyanate as a starting material, can be used. This is an example of the structure of the polyisocyanate. The substance has weather resistance, chemical resistance and heat resistance, and is particularly effective for weather resistance. In addition to these substances, diisophorone diisocyanate, diphenylmethane diisocyanate, bis (methylcyclohexyl) diisocyanate, toluene diisocyanate, and the like can also be used.

  The anti-fogging coating of the present invention exhibits anti-fogging properties only by the water absorption function of the coating without forming a water film when the anti-fogging property is exhibited. Saturation stops the development of anti-fogging properties. In order to obtain an excellent antifogging film, it is better that the time until water absorption is saturated is longer, and the water absorption capability of the film obtained by the coating agent for film formation of the present invention is that of the water absorbing component contained in the antifogging film. Depends on the amount. However, when the amount of the water-absorbing component is increased, the strength and durability of the coating tend to be reduced. Therefore, the ratio between the acrylic polyol and the polyoxyalkylene-based polyol is preferably adjusted as appropriate depending on the components to be used, but is usually “acryl polyol: polyoxyalkylene-based polyol = 30: 70 to 70:30 in mass ratio. It is enough if it is about. For example, when polyethylene glycol is used as the water-absorbing component, the component ratio is preferably “acryl polyol: polyethylene glycol = 60: 40 to 40:60” by mass ratio. By making it within this range, it is easy to achieve both the long time until water absorption is saturated and the strength and durability of the coating film. When the ratio of acrylic polyol to polyethylene glycol is a composition ratio in which the amount of polyethylene glycol is larger than the above range, problems such as a feeling of stickiness on the coating and a decrease in strength of the coating tend to occur. On the other hand, when the composition ratio is higher than the above range, the film thickness tends to increase in order to increase the time until water absorption is saturated, making it difficult to obtain a uniform film.

  The total number of isocyanate groups present in the isocyanate prepolymer is 1 to 2.5 times, more preferably 1.5 to 2.2 times the total number of hydroxyl groups present in the polyol component. It is preferable to prepare it. When the amount is less than 1 time, the curability of the coating agent is deteriorated and the formed film is soft, and the durability such as weather resistance, solvent resistance, and chemical resistance tends to decrease. On the other hand, when the amount exceeds 2 times, the antifogging property tends to be lowered due to excessive curing, which inhibits the absorption and dehydration of water vapor.

  The film of the present invention is a urethane resin obtained by a reaction of at least three components of the acrylic polyol, the polyoxyalkylene polyol, and the isocyanate prepolymer. An acrylic polyol having a high molecular weight having a number average molecular weight of 6000 to 18000 is used. When used, when the hydroxyl group of the acrylic polyol reacts with the isocyanate group of the isocyanate prepolymer to form a chemical bond, the acrylic polyol itself becomes a steric hindrance so that the reactivity is lowered and an acrylic polyol having a low molecular weight is used. Compared with the case where it was, the unreacted hydroxyl group tends to remain. Therefore, the isocyanate group can be combined with more polyoxyalkylene polyols, and as a result, high antifogging properties can be imparted to the resulting film. Furthermore, by leaving unreacted hydroxyl groups in the acrylic polyol, it is possible to impart hydrophilicity and adhesion to the substrate surface to the resulting coating.

In the coating of the present invention, considering the slip property of the coating described above and wiping workability during cleaning, the number of dimethylsiloxane units (Si (CH ₃ ) ₂ O) as a crosslinking unit is 5 to 300. It preferably has a chain polydimethylsiloxane component. In this case, the linear polydimethylsiloxane is introduced into the film by forming a urethane bond at the terminal portion. When the number of dimethylsiloxane units is less than 5, there is no effect in improving the slip property of the coating film. On the other hand, when it exceeds 300, the portion where the urethane bond of the linear polydimethylsiloxane is to be formed is relatively low. Therefore, there is a high possibility that the linear polydimethylsiloxane is not taken into the resin as a cross-linking unit at the time of resin formation, and as a result, the obtained coating is preferable because the linear polydimethylsiloxane is easily eluted. Absent.

  The antifogging film of the present invention comprises an antifogging film-forming coating agent (hereinafter simply referred to as “coating agent for film formation”) containing at least all of the three components of acrylic polyol, polyoxyalkylene polyol and isocyanate prepolymer. ”Or“ coating agent ”) is applied to the base material, and the liquid applied to the base material is cured by standing at room temperature or performing a heat treatment.

  In addition, since the coating film is made of a urethane resin from which at least the acrylic polyol, polyoxyalkylene polyol and isocyanate prepolymer can form a chemical bond, the drug A containing at least the two kinds of polyol components, and at least the isocyanate prepolymer. It is one of the preferred forms that it is divided into the medicine B containing a polymer and mixed each time it is used to form the coating agent for film formation. By adopting such a form, long-term storage stability in a form that is most easily used can be secured. In addition, by dividing and storing the two medicines in this way, the number of preparation steps when using them can be minimized.

  A surfactant can be added to the drug A, the drug B, or a coating agent obtained by mixing them to improve leveling properties and obtain a smooth coating. Thereby, it becomes easy to make the thickness of the coating film uniform when the coating agent is applied to the surface of the transparent substrate. As the surfactant, it is preferable to use a silicone surfactant, an acrylic surfactant, or the like. Specifically, BYK-Chemie's BYK-077, BYK-085, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-310, BYK- 320, BYK-322, BYK-323, BYK-325, BYK-330, BYK-331, BYK-333, BYK-335, BYK-341v344, BYK-345v346, BYK-348, BYK-354, BYK-355, BYK-356, BYK-358, BYK-361, BYK-370, BYK-371, BYK-375, BYK-380, or BYK-390 can be used, and DIC (DaiNippon) can be used as the fluorosurfactant. Ink & Chemicals F-114 F-177, F-410, F-411, F-450, F-493, F-494, F-443, F-444, F-445, F-446, F-470, F-471, F- 472SF, F-474, F-475, F-477, F-478, F-479, F-480SF, F-482, F-483, F-484, F-486, F-487, F-172D, MCF-350SF, TF-1025SF, TF-1117SF, TF-1026SF, TF-1128, TF-1127, TF-1129, TF-1126, TF-1130, TF-1116SF, TF-1131, TF1132, TF1027SF, TF- 1441, TF-1442, or the like can be used, but is not limited thereto.

  The surfactant is in a mass ratio of 0.0001 to the total amount of the acrylic polyol, polyoxyalkylene polyol and isocyanate prepolymer (hereinafter, the total amount may be referred to as “urethane forming component total amount”). The amount is preferably 0.007 times. When the content of the surfactant is increased, the quality of the obtained film is affected by the surfactant, and it may be difficult for the resulting film to exhibit antifogging properties, and the appearance and film strength may be impaired. On the other hand, when there is little content of surfactant, the effect which equalizes the thickness of the coating film at the time of apply | coating an application agent on the transparent base material surface is not fully acquired.

  Moreover, the said chemical | medical agent A, the chemical | medical agent B, or the coating agent which mixed them may be diluted with the solvent. As a diluting solvent, it is necessary to use a solvent that is not active with respect to the isocyanate group. From the viewpoint of compatibility with these coating agents, it is preferable to use acetate solvents and ketones. Specifically, the acetate solvent includes amyl acetate, allyl acetate, isoamyl acetate, isobutyl acetate, isopropyl acetate, ethyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, n-butyl acetate, s-acetate. Examples thereof include butyl, propyl acetate, benzyl acetate, methyl acetate, methyl cyclohexyl acetate, and ketones include acetylacetone, acetone, isophorone, ethyl-n-butylketone, diisobutylketone, diisopropylketone, diethylketone, cyclohexanone, di- n-propyl ketone, methyl oxide, methyl-n-amyl ketone, methyl isobutyl ketone, methyl ethyl ketone, methyl cyclohexanone, methyl-n-butyl ketone, methyl-n-propyl ketone, methyl-n-hexyl ketone, methyl-n Heptyl ketone, include diacetone alcohol, in particular, isobutyl acetate, n- butyl acetate s- butyl, methyl ethyl ketone or the like.

  When diluting the said coating agent, the density | concentration of the urethane formation component total amount in a coating agent should just be about 10-50 mass%. When the coating agent is obtained by mixing the drug A and the drug B, the concentration of the total amount of the acrylic polyol and the polyoxyalkylene polyol in the drug A is 15 to 40% by mass, and the concentration of the isocyanate prepolymer in the drug B is It is preferable from the surface of operativity to dilute in the range of 30-80 mass%.

  Furthermore, in order to increase the curing rate of the film, the drug A, the drug B, or a coating agent obtained by mixing them is used as an organic tin compound, an organic titanium compound, an organic zirconium compound, an organic bismuth compound or the like as a curing catalyst. A metal compound or an amine compound may be added.

  Examples of the organic tin compound include dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dibutyltin dioctoate, dibutyltin diacetate, dibutyltin mark carboxylate, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin markerbutide, dioctyltin thiol For organic titanium compounds such as carboxylate, titanium tetraisopropoxide, titanium tetranormal butoxide, titanium tetraacetylacetonate, titanium diisopropoxybis (triethanolaminate), titanium lactate, etc. Tributoxy monoacetylacetonate, zirconium tetranormal butoxide, zirconium tetraacetylacetonate, zirconium tetraacetylacetate Toneto like, the organic bismuth compound, a compound having a carboxylate (e.g., King industry Co. trade name: K KAT 348) but the like, but is not limited thereto. Examples of amine compounds include diethylamine, dimethylethanolamine, 1,8-diazabicyclo (5,4,0) -undecene-7, 1,5-diazabicyclo (4,3,0) -nonene-5, and amines thereof. Examples include, but are not limited to, salts of compounds. Preferred examples include dibutyltin dilaurate, zirconium tributoxy monoacetylacetonate, 1,8-diazabicyclo (5,4,0) -undecene-7 octylate, and the like.

  The addition amount of the curing catalyst depends on the compound to be used, but it is usually sufficient to add about 0.001 to 0.5% by mass with respect to 100% by mass of the total urethane-forming component.

Furthermore, in order to improve the slip property of the coating surface, in order to introduce a linear polydimethylsiloxane unit into the urethane resin of the coating, it has functional groups capable of reacting with isocyanate groups at both ends, and a dimethylsiloxane unit (Si It is also one of preferable modes to add linear polydimethylsiloxane having 5 to 300 (CH ₃ ) ₂ O) to the drug A, drug B, or a coating agent obtained by mixing them.

  As the functional group capable of reacting with the isocyanate group, active hydrogen bonded to oxygen, nitrogen, sulfur having a large electronegativity such as hydroxyl group, carboxy group, amino group, imino group, mercapto group, sulfino group, sulfo group, etc. Including functional groups can be used. Among these, considering the ease of handling, pot life when used as a coating agent, and durability of the resulting film, it is preferable to use a hydroxy group as a functional group capable of reacting with an isocyanate group. Specifically, DMS-S12, DMS-S14, DMS-S15, DMS-S21, DMS-S27, DMS-S31, DMS-S32, DMS-S33, DMS-S35, DMS-S42, DMS manufactured by Gelest -S45, DMS-S51, PDS-0338, PDS-1615, PDS-9931 and the like can be used, but are not limited thereto.

  The linear polydimethylsiloxane is preferably added in an amount of 0.05 to 3.0% by mass with respect to 100% by mass of the total urethane-forming component.

  Furthermore, a silicon compound may be introduced in order to improve the abrasion resistance and scratch resistance of the coating. The silicon compound can be added to the drug A or the coating agent, and it is preferable to introduce colloidal silica having an average particle diameter of 5 to 50 nm, a silicon compound having an alkoxy group, or the like. In the case where colloidal silica and a silicon compound having an alkoxy group include a functional group that reacts with an isocyanate group such as a hydroxyl group, when such a silicon compound is added to the drug B, the isocyanate group in the isocyanate prepolymer is converted into the silicon compound. When consumed by reaction with the compound, the curability of the coating agent may decrease. Therefore, it is a more preferable form that the silicon compound is added to the drug A. In addition, the average particle diameter here is obtained by a method based on JIS H 7803 (2005).

  The coating agent for film formation obtained by mixing the drug A and the drug B can be applied to a transparent base material to which antifogging property is to be imparted. Known means such as spin coating, dip coating, flow coating, roll coating, spray coating, screen printing and flexographic printing can be employed. After application, the liquid applied to the substrate is cured by standing at room temperature of about 20 ° C. or heat treatment up to 170 ° C. to form an antifogging film on the substrate. If the temperature of this heat treatment exceeds 170 ° C., care should be taken because the urethane resin is carbonized and the film strength is reduced. In consideration of acceleration of the coating, it is preferable to perform heat treatment at 80 to 170 ° C.

  As the transparent substrate, glass is typically used. The glass is a plate glass usually used for automobiles, architectural and industrial glasses, and is a plate glass by a float method, a duplex method, a roll-out method, etc., and the manufacturing method is not particularly limited.

  As glass types, it can be used for various colored glasses such as clear, green and bronze, various functional glasses such as UV, IR cut glass and electromagnetic shielding glass, netted glass, low expansion glass, zero expansion glass and fireproof glass. Various glass products such as glass, tempered glass, similar glass, laminated glass, multilayer glass, flat plate, bent plate and the like can be used.

  The plate thickness is not particularly limited, but is preferably 1.0 mm or more and 10 mm or less, and particularly preferably 1.0 mm or more and 5.0 mm or less. The antifogging film may be formed on the substrate surface only on one side of the substrate or on both sides depending on the application. Further, the antifogging film may be formed on the entire surface or a part of the substrate surface.

  When a coating agent is applied to a glass substrate to form a coating, a liquid having a silane coupling agent is added to the glass substrate before application of the coating agent in order to improve the adhesion between the substrate and the coating. It is preferable to apply to the surface. Suitable silane coupling agents include amino silanes, mercapto silanes and epoxy silanes. Preferred are γ-glycidoxypropyltrimethoxy, γ-aminopropyltriethoxysilane and the like.

  In addition to the glass, the transparent substrate may be a resin film such as polyethylene terephthalate, a resin such as polycarbonate, and the like. The antifogging film may be formed on the surface of the transparent resin substrate to form an antifogging article, and the article may be attached to a glass substrate.

  Hereinafter, the present invention will be described specifically by way of examples. In this example, as an acrylic polyol, a trade name “Acridic DU-1446-X” manufactured by DIC Corporation having a hydroxyl value of 33 mgKOH / g and a number average molecular weight of 14,000 is used. In addition, quality evaluation was performed with the method shown below with respect to the anti-fogging film obtained by the present Example and the comparative example.

  [Appearance evaluation]: The appearance, permeability, and presence / absence of cracks of the anti-fogging coating film were visually evaluated, and those having no problem were evaluated as acceptable (◯) and those having problems as unacceptable (×).

  [Haze]: Measured with NDH2000 manufactured by Nippon Denshoku in accordance with “JIS R 3212 (1998)”.

  [Anti-fogging evaluation]: Hot water in which the coating surface of the anti-fogging article having an anti-fogging coating formed on the surface of the base material is set at 43 ° C. in a room temperature room (temperature 24 ° C., humidity 45%). When held in the state of being exposed to saturated steam, the time until cloudiness was confirmed in an area of about 10% of the antifogging coating was measured.

  [Taber abrasion resistance]: In accordance with “JIS R 3212 (1998)”, a Taber abrasion test (4.9 N × 100 rotations) is performed, and the haze before and after the test is measured. The Δhaze value (%), which is the difference between the values, was calculated.

  [Pencil hardness]: According to “JIS K 5600 paint general test method”, the surface of the film was scratched 5 times with a pencil loaded with 750 g, and the pencil whose film was broken less than 2 times was defined as pencil hardness. . The pencil hardness can be used as an index of scratch resistance.

[Measurement of film thickness]: The film on the substrate is scraped off with a precision screwdriver with a width of about 1.5 mm at the tip, and a step formed between the film and the substrate is detected with a high-precision fine shape measuring instrument (SUREFCORDER ET 4000A Kosaka The film thickness of the coating was measured by measuring with a laboratory.

[Example 1]
(Preparation of coating agent for forming anti-fogging film)
14.5 g of dilute solvent n-butyl acetate was mixed with 10.5 g of hexamethylene diisocyanate burette type polyisocyanate (trade name “N3200”, manufactured by Sumitomo Bayer Urethane) as an isocyanate prepolymer having an isocyanate group, followed by stirring. 25 g of Drug B was obtained.

  To 46.37 g of n-butyl acetate as a diluent solvent, 10.7 g of polyethylene glycol (trade name “polyethylene glycol 1,000” / alias “PEG1000”; manufactured by Kishida Chemical Co., Ltd.) having a number average molecular weight of 1000 and a hydroxyl value of 33 mgKOH / 17.6 g of a mixed solution of n-butyl acetate, xylene and ethylbenzene (trade name “Acridic DU-1446-X”; manufactured by DIC Corporation) having 50% by mass of acrylic polyol of 1 g is further mixed with dimethylsiloxane. By adding 0.3 g of polydimethylsiloxane (“DMS-S12”; manufactured by Gelest. Inc) and 0.03 g of a surfactant (“BYK-301”; manufactured by BYK Chemie) having 7 units, the mixture was stirred. 75 g of Drug A was obtained. The acrylic polyol and the polyoxyalkylene polyol (polyethylene glycol) were prepared so that the mass ratio (hereinafter sometimes referred to as “AP: PO ratio”) was “AP: PO = 45: 55”.

  By mixing 0.009 g of dibutyltin dilaurate (hereinafter referred to as DBTDL) as a curing catalyst, 100 g of an antifogging film-forming coating agent was prepared (the “catalyst” in Table 1). “Concentration” means the mass% concentration of the curing catalyst with respect to 100% by mass of the total urethane-forming component).

  The total urethane-forming component amount in 100% by mass of the coating agent for forming an antifogging film prepared here is 30% by mass (described as “total urethane-forming component concentration” in Table 1). Further, the number of isocyanate groups present in the isocyanate prepolymer component of the drug B is 1.8 times the number of hydroxyl groups present in the acrylic polyol component and the polyoxyalkylene polyol component in the drug A ( In Table 1, described as “NCO / OH ratio”).

(Production of an article with an antifogging film)
γ-aminopropyltriethoxysilane (LS-3150, manufactured by Shin-Etsu Silicone) was diluted with denatured alcohol (Echinen F-1, manufactured by Kishida Chemical Co., Ltd.) consisting of 90% by mass of ethanol and 10% by mass of isopropyl alcohol. A 1% by weight solution was prepared. Next, 100 mm × 100 mm (3.5 mm thickness) of a wiper made of cellulose fibers that absorbed the solution (trade name “Bencot”, model M-1, 50 mm × 50 mm, manufactured by Ozu Sangyo) was obtained by the float method. The solution was applied by wiping the surface of the glass substrate, dried at room temperature, and then washed with water with a wiper using tap water to prepare a transparent glass substrate.

  A coating agent for forming the antifogging film obtained above is applied to the transparent glass substrate by spin coating, and the glass plate after coating is heat-treated at about 110 ° C. for about 30 minutes, thereby obtaining a film thickness of 25 μm. An antifogging article having an antifogging film was obtained.

As shown in Table 1, the antifogging article obtained by the above method was confirmed to be an article having various performances. “Taber” means Δhaze value (%), which is a difference between haze values before and after the test in the Taber abrasion resistance test.

[Examples 2 to 7]
As shown in Table 1, the AP / PO ratio and linear polydimethylsiloxane used in the examples were varied and evaluated. In all of the examples and comparative examples, in addition to the acrylic polyol and polyoxyalkylene polyol, the drug A contains a silicone surfactant (“BYK-301”; manufactured by BYK Chemie) as a surfactant, and the total amount of urethane-forming components. 0.106% by mass with respect to 100% by mass, and similarly, polydimethylsiloxane (“DMS-S12”; manufactured by Gelest. Inc.) as a linear polydimethylsiloxane component is added to drug A with respect to 100% by mass of the total urethane-forming component. 1.06 mass% was added.

[Comparative example]
As shown in Table 1, the type of acrylic polyol and the ratio of the acrylic polyol to the polyoxyalkylene polyol were changed, and the others were carried out and evaluated in the same manner as in the examples. In the acrylic polyol of Table 1, “desmophen A265BA” is a n-butyl acetate solution (manufactured by Sumika Bayer Urethane Co., Ltd.) having 65% by mass of an acrylic polyol having a hydroxyl value of 69 mgKOH / g and a number average molecular weight of 2,900. "Desmophen A365BA / X" means a mixed solution of n-butyl acetate and xylene having a hydroxyl value of 96 mgKOH / g and an acrylic polyol having a number average molecular weight of 3,900 of 65% by mass and xylene (manufactured by Sumika Bayer Urethane Co., Ltd.) It is.

  The film formed without using acrylic polyol as in Comparative Example 1 resulted in significantly inferior film strength compared to those using acrylic polyol (see Examples 1-7 and Comparative Examples 2-3). It was. In Comparative Examples 2 and 3, when an acrylic polyol having a small number average molecular weight was used, the appearance became cloudy (Comparative Example 2) or the antifogging property was lowered (Comparative Examples 2 and 3).

Claims (7)

An antifogging film formed on a transparent substrate, the film being made of a urethane resin, the urethane resin having at least the following three components: a) an acrylic polyol having a number average molecular weight of 6000 to 18000 b) number Polyoxyalkylene polyol having an average molecular weight of 400 to 5000 c) A resin obtained by reaction of an isocyanate prepolymer.   The antifogging film according to claim 1, wherein the acrylic polyol has a hydroxyl value of 20 to 60 mg KOH / g.   The antifogging according to claim 1 or 2, wherein a mass ratio of the acrylic polyol and the polyoxyalkylene polyol is in a range of acrylic polyol: polyoxyalkylene polyol = 30:70 to 70:30. Coating. The linear polydimethylsiloxane component having 5 to 300 dimethylsiloxane units (Si (CH ₃ ) ₂ O) as a crosslinking unit is further introduced into the urethane resin. 4. The antifogging film according to any one of items 1 to 3.   An antifogging window material comprising the coating according to any one of claims 1 to 4 and a transparent substrate.   A coating agent for forming an antifogging film according to claim 1, wherein at least the acrylic polyol and the drug A containing the polyoxyalkylene polyol, and at least the isocyanate prepolymer. A coating agent for forming an antifogging film obtained by mixing with the drug B to be contained.   It is a manufacturing method of the anti-fogging window material of Claim 5, Comprising: The chemical | medical agent A containing at least the said acrylic polyol and the said polyoxyalkylene-type polyol, and the chemical | medical agent B containing at least the said isocyanate prepolymer are mixed. A method for producing an antifogging window material, comprising applying the coating agent for forming an antifogging film obtained on the surface of the transparent base material and allowing the base material to stand at room temperature or heat treatment.