JP2005187276A - Anti-fogging glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide anti-fogging glass which makes it easy to secure the sight field of windows even in the winter season in which the temperature difference between outdoor temperature and indoor temperature is large, especially in a cold area which can be in an environment where the temperature is below zero, especially which is suitable to windows for vehicles. <P>SOLUTION: This anti-fogging glass is equipped with a coating film adhering to a glass base material which comprises a polyurethane of which the coating film exhibits water absorbability and hydrophilicity, and the polyurethane has an oxyethylene chain, and the contact angle of a water drop to the coating film is 40 degrees or lower even in the state where the coating film does not absorb water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antifogging glass that can be suitably used for a vehicle window.

  Glass is used as a transparent substrate in vehicle window glass, architectural window glass, lenses, goggles and the like. However, when the glass is used in a place with high humidity or at a boundary having a large temperature difference or humidity difference, condensation occurs on the surface and fogging occurs. For example, when a vehicle is driven in the rainy season with high humidity and in the winter when the temperature is low, the occurrence of cloudiness in the window is inevitable, and in order to secure a field of view, warm air, cold air, etc. are blown to the window, A dry state is usually performed.

  Therefore, the energy consumed for securing the visibility of the window is large, which has been a foothold for improving the fuel consumption characteristics of the vehicle. In particular, in winter when the temperature difference between indoors and outdoors becomes severe, especially in cold regions where the environment can be below freezing, the energy consumed to ensure the visibility of the windows increases. Also, there are problems such as increased discomfort in the vehicle interior due to the dry state, and providing a window glass that can reduce these problems, that is, providing an anti-fog glass, is for an environment-friendly vehicle. Is indispensable. Furthermore, it is expected that the need for anti-fogging glass will increase more and more in electric vehicles such as hybrid vehicles and fuel cell vehicles.

  As a vehicle antifogging glass, Patent Document 1 discloses an antifogging vehicle 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. However, since the means of developing antifogging properties in these documents is mainly due to the formation of a water film in the hydrophilic layer, the water film freezes in a sub-freezing environment, so that the frozen water film is melted. Problems such as requiring energy consumption for wind transmission occur.

Patent Document 1 discloses the use of a silica fine particle-based porous film and a water-absorbent resin as those that exhibit anti-fogging properties due to water absorption. Therefore, problems such as a decrease in translucency due to freezing of the absorbed water and destruction of the film may occur. In addition, these water-absorbing membranes do not have sufficient water-absorbing ability, and further improvement is necessary for the development of anti-fogging properties due to water absorption.
JP 2000-239045 A JP 2003-321251 A

  It is an object of the present invention to provide an anti-fogging glass that makes it easy to ensure the visibility of a window even in winter when the temperature difference between indoors and outdoors becomes severe, particularly in a cold region that can become a sub-freezing environment.

  In order to develop anti-fogging properties even in cold regions where windows can be below freezing, water absorbed in the coating does not freeze when water vapor contacts the coating formed on the glass substrate. Must be incorporated into the coating. The present invention has been made to achieve this, and if water absorbed in the coating is incorporated into the components in the coating as bound water, the absorbed water is not frozen and the glass visibility is secured. I found out that I can do it.

  That is, the antifogging glass of the present invention comprises a glass substrate and an antifogging glass provided with a coating in close contact with the glass substrate, the coating comprising a polyurethane exhibiting water absorption and hydrophilicity, and the polyurethane has an oxyethylene chain. And the contact angle of water droplets to the coating is 40 ° or less when the coating is not absorbing water. Here, the film in close contact with the glass substrate refers to a film that is not peeled off by an artificial operation such as scratching, and a film in which the film itself or components in the film are not eluted over time.

  Since water and oxygen in the oxyethylene chain are hydrogen-bonded, the water absorbed by the coating is taken into the oxyethylene chain as bound water as bound water. Therefore, the presence of oxyethylene chains in the coating makes it possible to develop antifogging properties due to water absorption even in sub-freezing environments.

  When water is bonded at the oxyethylene chain portion, a hydroxyl group is generated at the chain portion. When the water absorption in the coating reaches saturation, the hydroxyl group appears on the surface of the coating, so that the formation of a water film on the coating is promoted, so that the antifogging property can be maintained. In the state of water absorption saturation in the film, for example, the vehicle interior temperature has risen, and the water film hardly freezes. Even when the field of view is ensured, the amount of energy consumed by hot air, cold air, etc. can be suppressed, and the fuel efficiency characteristics of the vehicle are improved.

  In addition, by setting the contact angle of water droplets to the coating to be 40 ° or less when the coating is not absorbing water, it becomes possible to immediately exhibit antifogging properties even when the environment becomes cloudy. 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. 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).

  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.

  The anti-fogging glass of the present invention preferably has a water absorption rate of 15% by weight or more and 30% by weight or less when the film is saturated with water. Here, the water absorption rate indicates the weight ratio of water present in the coating film based on the weight of the coating film in the state of no water absorption. The water absorption rate to the film 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 less effective, and if it exceeds 30% by weight, the durability of the film is poor. It is because it tends to become. 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.

  Furthermore, 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 is likely to occur and productivity is reduced. Considering more efficient productivity, the film thickness is preferably 35 μm or less.

  In addition, in view of the durability of the antifogging glass, it is preferable that the hardness of the coating is set in the range of HB to F when the pencil hardness of the coating obtained according to “JIS K 5400” is saturated with water absorption of the coating. . In addition, when the antifogging glass is mounted as a window for a vehicle, it is assumed that the coating is frequently wiped by cloth, a cloth, etc., so in order to prevent the coating from being damaged by wiping, It is preferable that the static friction coefficient of the coating obtained in accordance with “JIS K 7125” is 0.4 or more and 0.8 or less in a state where the coating does not absorb water.

  The anti-fogging glass of the present invention has excellent anti-fogging properties such as exhibiting anti-fogging properties even in a sub-freezing environment, and immediately developing anti-fogging properties even in a cloudy environment. Moreover, since it is excellent also in durability, it can endure long-term use. Therefore, when the anti-fogging glass of the present invention is used as a window, it is easy to secure a field of view, and when used as a window for a vehicle, the effect is particularly remarkable, improving safety and improving fuel consumption characteristics of the vehicle. Contribute to.

  The antifogging glass of the present invention comprises a glass substrate and a coating that is in close contact with the glass substrate. As the glass substrate, a plate glass that is usually used for automobiles, buildings, industrial glasses, and the like, and manufactured by a float method, a duplex method, a roll-out method, or the like can be used. Glass types include various colored glasses such as clear glass, green glass, and bronze glass, various functional glasses such as UV, IR cut glass, and electromagnetic shielding glass, netted glass, low expansion glass, and fireproof glass such as zero expansion glass. Various glass products such as glass that can be provided, tempered glass and the like, laminated glass, multi-layer glass, and plastic glass can be used.

  The plate thickness of the glass substrate 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 coating on the substrate may be performed on only one side of the substrate or on both sides. Further, the film may be formed on the entire surface or a part of the substrate surface.

  As the coating, a coating made of polyurethane can be used. Polyurethane, which has the elasticity inherent in urethane, has characteristics such as excellent wear resistance compared to other resins, and is particularly suitable for use in vehicle windows. is there.

  Polyurethane is obtained by reacting an isocyanate prepolymer (chemical species having an isocyanate group) with a polyol, and the function of the film is set depending on the type of polyol and other chemical species to be introduced. At this time, it is preferable to adjust the number of isocyanate-reactive groups such as a hydroxyl group, an amino group, a mercapto group, etc. with respect to the isocyanate group in the vicinity of the stoichiometry.

  A coating agent having an isocyanate prepolymer, a polyol, and other chemical species and / or their reaction products is applied to a glass substrate by a known application means such as a spin coat method, a dip coat method, or a flow coat method, and cured. Thus, a film can be obtained, and the curing can be performed by standing at room temperature or heating up to 170 ° C.

  In order to further improve the durability of the antifogging glass, a treatment for improving the adhesive strength between the glass substrate and the coating film can be performed in advance on the glass substrate. And in order to improve the durability with respect to the alkaline solution of anti-fogging glass, you may modify the surface of a glass base material using the composition of a silane coupling agent and a hydrolyzable zirconia precursor.

  The silane coupling agent includes monomethylsilanol, dimethylsilanol, trimethylsilanol, silanol (tetrahydroxysilane), monoethylsilanol, diethylsilanol, triethylsilanol, monopropylsilanol, dipropylsilanol, tripropylsilanol, triisopropylsilanol, Diphenylsilanediol, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, etc. can be used. As the zirconia precursor, zirconium oxychloride, zirconium nitrate, zirconium acetate, alkoxide compounds and the like can be used.

  As the isocyanate prepolymer, a compound having an isocyanate group, preferably a biuret starting from hexamethylene diisocyanate and / or a trifunctional polyisocyanate having an isocyanurate structure 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 bifunctional and / or trifunctional polyisocyanate having an isocyanurate structure starting from diisocyanate, preferably 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. In particular, it is preferable to introduce so that the static friction coefficient of the coating obtained in accordance with “JIS K 7125” is 0.4 or more and 0.8 or less in a state where the coating does not absorb water.

  In order to improve the wear resistance of the coating, a metal oxide precursor and a silane coupling agent may be introduced into the coating agent. As the metal oxide precursor, alkoxide compounds such as ethoxide compounds and methoxide compounds, oxyhalogen compounds, acetyl compounds, and the like can be used. 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 the economical viewpoint. The metal oxide precursor may be added in an amount up to 1.25 times by weight with respect to the total amount of isocyanate prepolymer, polyol, and surfactant having an isocyanate-reactive group (hereinafter referred to as the total urethane component amount). it can. If the amount exceeds 1.25 times, the antifogging property of the resulting film is lowered. From the viewpoint of improving the wear resistance, the metal oxide precursor is preferably added up to 0.1 times the weight of the urethane component.

  The silane coupling agent can be added up to 0.25 times by weight with respect to the total amount of urethane components. If the amount exceeds 0.25 times, the strength of the film obtained due to the unreacted functional group of the silane coupling agent is lowered, and the surface of the film becomes sticky. In order to crosslink the metal oxide derived from the precursor of the metal oxide and the urethane resin, the silane coupling agent is preferably added in an amount of 0.01 times by weight with respect to the total amount of the urethane component. It is particularly preferable that the silane coupling agent is 3-methacryloxypropyltrimethoxysilane or 3-glycidoxypropyltrimethoxysilane because a homogeneous film can be easily obtained.

  In order to improve the scratch resistance of the coating, the coating agent can contain fine particles of metal oxide such as silica, titania, zirconia, alumina, niobium oxide, tantalum oxide having an average particle size of 5 nm to 50 nm, particularly It is preferable to contain colloidal silica. When the metal oxide fine particles are contained, since it is important not to lower the antifogging property of the antifogging film, the content thereof is 40% by weight or less, preferably 20% by weight based on the total amount of urethane components. % Or less, more preferably 10% by weight or less. The average particle size referred to here is the visual reading of the particle size of all the particles existing within a range of 1 μm square when the cross section of the film is observed with a scanning electron microscope at a magnification of 100,000 times. The average value is calculated. This calculation is defined as an average value of values obtained by repeating 20 times.

  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 glass 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 glass substrate was measured, and [b−a] / [a− ( The value obtained by the formula of the weight of the glass substrate)] × 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 substrate glass surface wettability test method”. A 100 mm square flat antifogging glass is held for 12 hours in an environment of 50% humidity and a temperature of 55 ° C., and then held for 12 hours in an environment of the same humidity at a temperature of 25 ° C. A test piece was obtained. The test piece was placed on a contact angle meter (CA-2 type) manufactured by Kyowa Interface Chemical Co., Ltd., 2 μl of water was dropped on the coating, and the contact angle of the water droplet was measured. Moreover, 43 ° C. saturated water vapor was brought into contact with the coating of the test piece for 5 minutes, the coating was saturated with water, the test piece was placed on the contact angle meter, 2 μl of water was dropped on the coating, The contact angle was measured.

  [Anti-fogging property]: fogging condition when kept for 3 minutes in steam of warm water set at 43 ° C. according to “JIS S 4030 Anti-fogging agent test method for glasses” and normal temperature (23 ° C., humidity 63% ) Observe the cloudiness due to exhalation when taken out. This operation was carried out 10 cycles as 1 cycle. A film having no abnormality in the appearance of the film with no fogging was judged as acceptable (◯), and a film with fogging was judged as unacceptable (x).

  [Anti-freezing property under freezing point]: After being kept in a freezer set at −20 ° C. for 30 minutes, the appearance, cloudiness, and cloudiness due to breath are observed when taken out at room temperature (23 ° C., humidity 63%). This operation was carried out 10 times as 1 cycle, and the film appearance with no abnormality and no clouding occurred was judged as acceptable (O), and the film with clouding was judged as unacceptable (X). When the anti-fog glass that passes the test is mounted as a window for a vehicle, fogging of the window is less likely to occur even when traveling in a cold region where the environment can be below freezing. This contributes to safe driving of the vehicle.

  [Pencil hardness]: In accordance with “JIS K 5400 Paint General Test Method”, the surface of the film was scratched 5 times with a pencil to which a load of 1 kg was applied, and the pencil whose film was broken less than 2 times was defined as pencil hardness. . In addition, the sample used the thing whose film is a water absorption saturation state. 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. The antifogging glass used in the test is a 100 mm square flat plate.

[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]: According to "JIS K 7125 Plastic-film and sheet-Friction coefficient test method", a square sliding piece having a contact area of 40 cm ² (length of one side: 6.3 cm) is anti-fogged with a load of 200 g. The slip property was measured by placing on a conductive film. The bottom surface of the sliding piece (the contact surface with the specimen) was covered with flannel (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
As an isocyanate prepolymer, a solution having 73% by weight of hexamethylene diisocyanate (“VISGARD-B”; manufactured by Film Specialties) was prepared. This is designated coating agent A.

  “Sulphonic acid amine salt which is a surfactant having 63 parts by weight of isocyanate-reactive group, and 37 part by weight of water-absorbing polyol, an ethylene oxide / propylene oxide copolymer polyol having an average molecular weight of 2100 to 4500” Solution 1 having 27% by weight (“VISGARD-A”; manufactured by Film Specialties), and polyethylene glycol having an average molecular weight of 1000 as a water-absorbing polyol, and a solution having 80% by weight of polycarbonate polyol having an average molecular weight of 1250 as a hydrophobic polyol 2 ("PC-61"; manufactured by Nippon Polyurethane Co., Ltd.) was prepared.

  The solution 1, the solution 2 and the polyethylene glycol were mixed so that the amine polyol of sulfonic acid and the copolymer polyol of ethylene oxide / propylene oxide were 70 parts by weight, the polyethylene glycol was 10 parts by weight, and the polycarbonate polyol was 20 parts by weight. did. This is designated as coating agent B.

  To 100 g of coating agent B, 42 g of coating agent A was added and mixed so that the ratio of isocyanate group / isocyanate reactive group number was 1.0, and coating agent A and coating were applied so that the total amount of urethane components was 35% by weight. Diacetone alcohol was added to and mixed with the mixture of Agent B as a diluent solvent to obtain a coating agent for obtaining a film exhibiting water absorption and hydrophilicity.

  The coating agent is formed by bending soda lime glass with a thickness of 1500 mm × 990 mm with a thickness of 2 mm, the line connecting the upper corner and the center of the upper side are separated by 60 mm, and the line connecting the lower corner and the center of the lower side Was applied by flow coating to the inner peripheral side of a glass substrate that can be supplied as a window for an automobile having a curved surface in which a line connecting the centers of the upper side and the lower side and a glass central part is 20 mm apart. The antifogging glass for both the [contact angle of water droplets on the coating] and the [Taber abrasion resistance] test was a flat plate of 100 mm × 100 mm (2 mm thick).

  And the anti-fog glass in which the film which consists of a polyurethane which has a 20-micrometer-thick oxyethylene chain was formed was obtained by heating the glass base material with which the coating agent was apply | coated at 150 degreeC for 30 minutes.

  As shown in Table 1, the antifogging glass obtained by the above method is an antifogging glass excellent in various antifogging performances, various abrasion resistances, water resistance, and the like, and is suitable for a vehicle window. It was confirmed that it was suitable for glass.

Example 2
In the preparation of the coating agent B in Example 1, the mixing ratio of each component was 60 parts by weight of sulfonic acid amine salt and ethylene oxide / propylene oxide copolymer polyol, 20 parts by weight of polyethylene glycol, and polycarbonate polyol. Except that the amount was 20 parts by weight, the same operation as in Example 1 was performed to obtain an antifogging glass on which a film made of polyurethane having an oxyethylene chain with a film thickness of 16 μm was formed. As shown in Table 1, the obtained antifogging glass is an antifogging glass excellent in various antifogging performances, various abrasion resistances, and water resistance, and is suitable for an antifogging glass suitable for a vehicle window. It was confirmed.

Example 3
In the preparation of coating agent B in Example 1, the mixing ratio of each component was 60 parts by weight of sulfonate amine salt and ethylene oxide / propylene oxide copolymer polyol, 15 parts by weight of polyethylene glycol, and 25 parts by weight of polycarbonate polyol. Except for the part, the same operation as in Example 1 was performed to obtain an antifogging glass on which a film made of polyurethane having an oxyethylene chain with a thickness of 20 μm was formed. As shown in Table 1, the obtained antifogging glass is an antifogging glass excellent in various antifogging properties, various abrasion resistances, and water resistance, and is suitable for an antifogging glass suitable for a vehicle window. It was confirmed that there was.

Example 4
The same operation as in Example 1 was carried out except that the amount of the coating agent A added to the coating agent B was 58 g so that the ratio of isocyanate group / isocyanate reactive group number in Example 1 was 1.4, An antifogging glass having a film made of polyurethane having an oxyethylene chain with a thickness of 22 μm was obtained. As shown in Table 1, the obtained antifogging glass is an antifogging glass excellent in various antifogging properties, various abrasion resistances, and water resistance, and is suitable for an antifogging glass suitable for a vehicle window. It was confirmed that there was.

Example 5
A hexamethylene diisocyanate burette type polyisocyanate (trade name “N3200”, manufactured by Sumika Bayer Urethane) was prepared as an isocyanate prepolymer. This is designated coating agent A.

  17.5 g of ricinoleamidopropylethyldimonium ethosulphate (trade name “Lipoquat®” manufactured by Lipochemicals Inc) as a surfactant having an isocyanate reactive group, 20.0 g of polyethylene glycol having an average molecular weight of 1000 as a water-absorbing polyol As a hydrophobic polyol, 10.5 g of polycaprolactone diol having an average molecular weight of 500 (trade name “Plaucel L205AL” manufactured by Daicel Chemical Industries), a short-chain polyol and 5.0 g of triethanolamine were mixed. This is designated as coating agent B.

  47 g of coating agent A was added to coating agent B so that the ratio of isocyanate group / isocyanate-reactive group number was 1.2 with respect to coating agent B to obtain a mixture. Diacetone alcohol is added as a diluting solvent so that the concentration of the total amount of urethane components is 35% by weight, and 0.005% by weight of dibutyltin dilaurate is added as a curing catalyst to the total amount of urethane components. Thus, a coating agent was obtained.

  The same operation as in Example 1 was performed except that the preparation of the coating agent was performed as described above, to obtain an antifogging glass on which a film made of polyurethane having an oxyethylene chain having a thickness of 32 μm was formed. As shown in Table 1, the obtained antifogging glass is excellent in various antifogging performances, various abrasion resistances, and water resistance, and is confirmed to be suitable for an antifogging glass suitable for a vehicle window. It was done.

Comparative Example 1
The same operation as in Example 1 was carried out except that the additive amount of the coating agent B with respect to 100 g of the coating agent A was changed to 40 g without adding the water-absorbing polyol polyethylene glycol and the hydrophobic polyol polycarbonate polyol to the coating agent B. Then, an antifogging glass having a film thickness of 22 μm was obtained. As shown in Table 1, the obtained antifogging glass had a large contact angle of water droplets, and fogging occurred in antifogging property below freezing point. In addition, the traverse wear resistance and slip resistance were poor, and a sharp decrease in pencil hardness was confirmed in the water resistance test.

Comparative Example 2
Except that the hydrophobic polyol polycarbonate polyol is not added to the coating agent B, the polyethylene glycol of the water-absorbing polyol is 30 parts by weight, and the addition and mixing amount of the coating agent B to 100 g of the coating agent A is 30 g. The same operation as in No. 1 was performed to obtain an antifogging glass having a film thickness of 25 μm. As shown in Table 1, the obtained antifogging glass was confirmed to have a sharp decrease in pencil hardness in a water resistance test.

Comparative Example 3
The same as in Example 4, except that the water-absorbing polyol was not added to the coating agent B, the hydrophobic polyol was 26 g of polycaprolactone diol having an average molecular weight of 500, and the amount of the coating agent A added to the coating agent B was 52 g. The operation was performed to obtain an antifogging glass having a film thickness of 32 μm. As shown in Table 1, the obtained antifogging glass was fogged in the repeated antifogging test and the sub-freezing antifogging test.

Comparative Example 4
The same operation as in Example 4 was performed except that 34 g of the water-absorbing polyol was added to the coating agent B, the hydrophobic polyol was not added, and the amount of the coating agent A added to the coating agent B was 44 g, and the film thickness was 30 μm. Thus, an antifogging glass having a coating film was obtained. As shown in Table 1, the obtained anti-fogging glass was inferior in traverse wear resistance and slip resistance, and a sharp decrease in pencil hardness was confirmed in a water resistance test.

Claims (6)

A glass substrate, and an antifogging glass having a coating closely adhered to the glass substrate, the coating is made of polyurethane exhibiting water absorption and hydrophilicity, the polyurethane has an oxyethylene chain, and water droplets on the coating An antifogging glass having a contact angle of 40 ° or less in a state where the film does not absorb water. The anti-fogging glass according to claim 1, wherein the water absorption at the time of water absorption saturation of the coating is 15 wt% or more and 30 wt% or less. The antifogging glass according to claim 1 or 2, wherein the film has a thickness of 5 µm or more and 50 µm or less. The antifogging glass according to any one of claims 1 to 3, wherein the pencil hardness of the film obtained in accordance with "JIS K 5400" is HB to F when the film is saturated with water absorption. 5. The coefficient of static friction of the coating obtained in accordance with “JIS K 7125” is 0.4 or more and 0.8 or less when the coating does not absorb water. Antifogging glass according to crab. A vehicle equipped with the anti-fogging glass according to claim 1 as a window.