JP2012017220A - Anti-fog article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an anti-fog article having excellent in anti-fog properties, adhesiveness of a substrate and a film, and heat resistance.SOLUTION: There is provided an anti-fog article, comprising a substrate, a film containing a copolymer of binder components and polyacrylic acids, and a primer layer between the substrate and the film.

Description

  The present invention relates to an antifogging article that can be used for various applications such as antifogging window glass or antifogging mirrors, lenses, and displays for vehicles, buildings, etc., and is excellent in antifogging properties, adhesion, and heat resistance. .

  Transparent substrates such as glass and plastic have a sudden temperature change with respect to the substrate when one surface falls below the dew point due to the difference in temperature and humidity between the inner and outer surfaces of the substrate. In such a case (such as when boiling water vapor comes into contact with the substrate or when the low-temperature portion moves to a hot and humid environment), moisture in the atmosphere adheres as water droplets, and the substrate surface is condensed. As a result, the field of view is hindered by the so-called “cloudiness” in which light is scattered by the condensed water droplets. Such “cloudiness” significantly impairs safety and visibility in general window glass, windshields of automobiles and aircraft, reflectors, glasses, sunglasses, and the like.

  Patent Document 1 includes an antifogging coating material comprising an inorganic alkoxide, an inorganic alkoxide hydrolyzate and an inorganic alkoxide hydrolysis polycondensate, polyacrylic acid and polyvinyl alcohol, and Disclosed is an antifogging coating film mainly composed of a composition obtained by causing at least a polycondensation reaction of a hydrolyzate of an inorganic alkoxide in the presence of polyacrylic acid and polyvinyl alcohol.

  Patent Document 2 discloses an antifogging layer made of a polyvinyl acetal resin (polyvinyl phenylacetoacetal, polyvinyl benzacetal, polyvinyl butyral, etc.) having an acetalization degree of 2 to 40 mol%.

  Patent Document 3 discloses the use of an antifogging film and a primer containing an ultraviolet curable resin, a metal oxide, and a hydrophilic resin.

Japanese Patent Laid-Open No. 11-061029 JP-A-6-158031 JP 2003-26960 A

  Antifogging articles are desired to be able to maintain antifogging properties and visibility over a long period of time. Among the antifogging articles obtained in the inventions described in Patent Documents 1 and 2, water absorption In the coating film having swells, peeling from the substrate is likely to occur due to swelling during water absorption, and the anti-fogging property cannot be maintained after peeling, and thus the visibility tends to decrease. Antifogging articles are required to have heat resistance in applications where they are exposed to heat such as solar radiation for a long period of time. However, the antifogging article obtained in any of the inventions described in the above Patent Documents 1 to 3 tends to yellow when heated for a long period of time, and tends to cause problems in appearance and visibility. Then, this invention makes it a subject to obtain the anti-fogging article | item which is excellent in anti-fogging property, the adhesiveness of a base material and a film, and heat resistance.

  The antifogging article of the present invention is characterized by having a base material, a coating containing a binder component and a polyacrylic acid copolymer, and a primer layer between the base and the coating.

  The film is a film having both excellent heat resistance and antifogging properties due to the heat resistance of the component derived from the binder component and the water absorption and heat resistance of the component derived from the polyacrylic acid. By having a primer layer in the middle, excellent adhesion can be imparted between the substrate and the coating. As a result, an antifogging article having excellent antifogging properties, adhesion and heat resistance can be obtained.

Moreover, it is preferable that the said primer layer consists of a hydrolysis product of the silicon compound A represented by the following general formula [1].
R ¹ _m SiX _4-m [1]
In the formula [1], R ¹ is an organic group containing at least one group selected from the group consisting of an amino group, a glycidoxy group, and a mercapto group, X is an alkoxy group having 1 to 18 carbon atoms, m Is an integer from 1 to 3.

  The antifogging article of the present invention preferably has heat resistance against heat of 100 ° C. or lower. 100 degreeC assumes the thermal load of the glass for motor vehicles described in JISR3212 "Safety glass test method for motor vehicles".

  In the present invention, “having heat resistance to heat of 100 ° C. or less” means that the anti-fogging article is not exposed to heat of 100 ° C. or less and the visibility and antifogging of the article are It means that there is no problem in sex.

  Regarding visibility, it is preferable that no defects on the appearance such as coloring, cracking, precipitation of foreign matters, distortion, etc. occur in the article even after being exposed to heat of 100 ° C. or less.

  Regarding anti-fogging properties, even after being exposed to heat of 100 ° C. or less, for example, an anti-fogging test assuming an actual vehicle environment in a vehicle window glass (hereinafter referred to as an actual vehicle anti-fogging test). It is preferable that condensation does not occur for 10 minutes or more. Here, the actual vehicle assumed anti-fogging property test is a test in which a sample is installed between two chambers in which the temperature and humidity can be controlled as shown in FIG. The film side is assumed to be the inside of the vehicle and the substrate side is assumed to be the outside of the vehicle. The assumed outside temperature is assumed to be 20 ° C, the assumed inside temperature is 25 ° C, and the assumed inside humidity is 95%. Assuming winter, the assumed outside temperature is 0 ° C., the assumed inside temperature is 25 ° C., and the assumed inside humidity is 60%.

  Moreover, it is preferable that the antifogging article of the present invention has excellent adhesion between the substrate and the coating. Excellent adhesion means that the substrate and the coating do not physically peel easily due to interactions such as bond formation and hydrogen bonding. In particular, it is preferable that the coating does not peel from the substrate due to swelling during water absorption.

The binder component is preferably a silicon compound B represented by the following general formula [2], a compound C obtained by partially condensing the silicon compound B, or a mixture of B and C.
R ² _n SiY _4-n [2]
In the formula [2], R ² is at least one selected from the group consisting of a hydrocarbon group having 1 to 18 carbon atoms, or a partial hydrogen atom of the hydrocarbon group, an epoxy group, a glycidoxy group, and an amino group. An organic group substituted with a group. Y is at least one group selected from the group consisting of an alkoxy group, a chloro group, an isocyanate group, and a hydroxy group, and n is an integer of 0 to 3.

  The molecular weight of the polyacrylic acid is preferably 1,000 to 250,000. When the molecular weight is less than 1,000, there is a tendency that antifogging properties are not exhibited or sufficient antifogging properties cannot be obtained. When the molecular weight is more than 250,000, the viscosity of the coating agent increases greatly, and the film formability tends to decrease. In the present invention, the molecular weight is a weight average molecular weight.

The polyacrylic acids are
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or polymethacrylic acid ester, and
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or a compound in which a part of hydrogen atoms of the methylene chain of polymethacrylic acid ester is substituted with an epoxy group, a glycidoxy group, or a substituent having reactivity with an amino group It is preferably at least one selected from the group consisting of From the viewpoint of water absorption, polyacrylic acid, polymethacrylic acid and the like are particularly preferable.

  It is preferable that polyacrylic acid is 5-60 mass% with respect to the said binder component and the total amount of polyacrylic acid. If it is less than 5% by mass, the resulting coating film tends not to exhibit antifogging properties, or sufficient antifogging properties tend not to be obtained. If it exceeds 60% by mass, polyacrylic acids cannot be immobilized in the resulting coating, and the polyacrylic acids tend to elute upon water absorption. From the viewpoint of antifogging properties and immobilization of polyacrylic acids, the amount is more preferably 10 to 50% by mass, and still more preferably 20 to 40% by mass.

Moreover, it is preferable that the water absorption of the said film is performed with the component derived from polyacrylic acid which exists in this film, and the water absorption of the unit volume at the time of water absorption saturation of this film is 0.05-3 mg / mm < ³ >. The water absorption amount in the present invention indicates the mass of water present in the coating film based on the mass of the coating film in a state where no water is absorbed.

The amount of water absorption of the unit volume to the coating at the time of water absorption saturation is set in the above range. If it is less than 0.05 mg / mm ^3, it is necessary to increase the film thickness in order to lengthen the time until water absorption is saturated. As a result, optical distortion is likely to occur, and productivity may be lowered. This is because if it exceeds ³ mg / mm ³ , the sticky feeling of the coating is increased, the strength is lowered, and the water resistance is deteriorated. A more preferable unit volume of water absorption is 0.1 to 2 mg / mm ³ .

  If the component that contributes to water absorption in the coating is a component derived from polyacrylic acid, the coating itself has excellent heat resistance, so both antifogging properties and heat resistance are excellent in the resulting antifogging article. Can be made. A film that exhibits anti-fogging properties due to conventional water absorption may contain a component derived from polyvinyl alcohols or polyvinyl acetals as a water-absorbing component, but the polyvinyl alcohols or polyvinyl acetals in the coating obtained in the present invention. It is preferable that the component derived from a class is 5 mass% or less. If it exceeds 5% by mass, the film tends to be colored by heat of 100 ° C. or less, which is not preferable. A more preferable concentration of the component derived from polyvinyl alcohols or polyvinyl acetals in the coating is 1% by mass or less, more preferably 0.01% by mass or less. Further, in the obtained coating, the polyvinyl alcohols or It is particularly preferable that components derived from polyvinyl acetals are not substantially contained.

Moreover, it is preferable that the antifogging article of the present invention is produced through at least the following steps.
(1) A step of forming a primer layer comprising a hydrolysis product of the silicon compound A on the surface of the substrate (2) A step of preparing a coating agent for forming a film containing a binder component and polyacrylic acids (3) The coating A step of applying a coating agent for forming, and a step of (4) curing the coating film.

  Since the anti-fogging article of the present invention is excellent in anti-fogging properties, adhesion and heat resistance, it can be used in members and applications that are exposed to heat for a long period of time. Moreover, since it is difficult for a film to peel from a base material by swelling at the time of water absorption, anti-fogging property can be maintained over a long period of time. The effect is particularly remarkable when used for a window material for a vehicle, and a safe and comfortable interior environment can be provided.

Schematic diagram of actual vehicle anti-fogging test using a two-chamber environmental tester

  The antifogging article of the present invention is an antifogging article having a substrate, a coating containing a binder component and a polyacrylic acid copolymer, and a primer layer between the substrate and the coating.

The antifogging article of the present invention is produced through at least the following steps.
(1) The process of forming the primer layer which consists of a hydrolysis product of the silicon compound A represented by the said General formula [1] on the base-material surface (2) The coating agent for film formation containing a binder component and polyacrylic acid (3) a step of applying the coating agent for forming a film, and (4) a step of curing the coating film.

  As the substrate, those having light transmittance, light reflectivity, or glossiness, and those whose safety, appearance, and design properties are significantly impaired by fogging are used.

  Glass is used as a typical base material having optical transparency. 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. In addition to glass, tempered glass, similar glass, laminated glass, multilayer glass and the like can be used. In addition to the above plate glass, for example, a resin film such as polyethylene terephthalate, a resin plate such as polycarbonate and acrylic, and the like can also be used.

  Moreover, as a typical base material having light reflectivity, a mirror, a metal, a metal-plated article, or the like produced by a silvering method or a vacuum film forming method can be used.

  In addition, as a typical base material having gloss, metal, metal-plated articles, ceramics, and the like can be used.

  Various molded bodies, such as a flat plate and a bending board, can be used for said base material. The plate thickness is not particularly limited, but is preferably 1.0 mm or more and 10 mm or less. For example, the window material for a vehicle is preferably 1.0 mm or more and 5.0 mm or less.

  In addition, in order to improve the adhesion strength between the substrate surface and the primer layer, the substrate surface before forming the primer layer is subjected to treatment such as plasma irradiation, corona discharge, high-pressure mercury lamp irradiation, and the like. An active group (for example, a ketone group, an ether group, or an OH group) may be generated on the surface.

  The primer layer and the coating film may be formed on the substrate only on one side or on both sides. The primer layer and the film may be formed on the entire surface of the substrate or a part thereof.

The primer layer is preferably made of a hydrolysis product of silicon compound A represented by the following general formula [1].
R ¹ _m SiX _4-m [1]
In the formula [1], R ¹ is an organic group containing at least one group selected from the group consisting of an amino group, a glycidoxy group, and a mercapto group, X is an alkoxy group having 1 to 18 carbon atoms, m Is an integer from 1 to 3.

  By the interaction of the silanol group of the hydrolysis product of the silicon compound A and the active group (for example, ketone group, ether group, OH group, etc.) on the surface of the substrate, an interaction such as bond formation or hydrogen bond, the substrate And excellent adhesion between the primer layers.

  Furthermore, an organic group containing at least one group selected from the group consisting of an amino group, a glycidoxy group and a mercapto group of the hydrolysis product of the silicon compound A, a binder component of the coating before curing, and an active group of polyacrylic acid Excellent adhesion between the primer layer and the coating film is expressed by the interaction such as bond formation by reaction of OH group, glycidoxy group, etc. and hydrogen bond.

  Examples of the silicon compound A include trimethoxy [3- (phenylamino) propyl] silane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyltri Ethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propyltriethoxysilane, 3- Mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyldimethylmethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane Down, 3-mercaptopropyl dimethyl ethoxy silane, 3-mercaptopropyl (dimethoxy) methylsilane, and 3 (2-aminoethylamino) propyl dimethoxy methyl silane.

  The primer layer is obtained by hydrolyzing the silicon compound A, and a liquid obtained by mixing the silicon compound A with water, an acidic aqueous solution, or a basic aqueous solution and hydrolyzing the mixture is used. It can form by apply | coating to and drying. At this time, in order to adjust the compatibility of the silicon compound A and water, adjust the viscosity of the coating solution, or adjust the drying speed of the coating solution, the silicon compound A is in a solution state dissolved in a solvent. May be used. Further, the primer layer may be formed by applying the silicon compound A or a solution thereof to the surface of the base material in a state where it is hydrolyzed by moisture in the atmosphere and drying it.

  The solvent used for dissolving the silicon compound A is not particularly limited as long as it dissolves the silicon compound A. For example, water, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butanol, ethylene Examples include glycol, 1,2-propanediol, and cyclohexanol. Isopropyl alcohol is preferred from the viewpoint of price and safety. Moreover, it is good also as a mixed solvent using a some solvent.

  As a coating method of the hydrolysis product of the silicon compound A, for example, known coating means such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, flexographic printing, hand coating method, and ink jet method are used. Can be used.

  As a method for drying the hydrolysis product of the silicon compound A, wiping at room temperature is sufficient, but the solution is applied to the substrate in order to quickly develop the adhesion between the substrate and the primer layer. Later, it may be fired at 50 to 100 ° C.

  The coating film is preferably a composite film containing a binder component and a copolymer of polyacrylic acids. The coating film has excellent heat resistance and antifogging properties due to the heat resistance of the component derived from the binder component and the water absorption and heat resistance of the component derived from the polyacrylic acid.

  The expression of antifogging properties of the antifogging article of the present invention contributes to the absorption of water by components derived from polyacrylic acids. Further, in addition to the water absorption effect by the component derived from the polyacrylic acid, when the component derived from the binder component contains a hydroxyl group, a carbonyl group, an amino group, a carboxyl group, a sulfo group, etc., the water absorption effect is due to their hydrophilicity. It may be promoted. Further, as a component other than the polyacrylic acid and the binder component, by adding other components having a hydroxyl group, a carbonyl group, an amino group, a carboxyl group, a sulfo group, etc., the water absorption effect is obtained due to the hydrophilicity of the component. It may be promoted.

  The polyacrylic acid is copolymerized with a binder component to form a composite film containing a component derived from the polyacrylic acid and a component derived from the binder component. Elution of components derived from acids can be prevented, and antifogging properties can be expressed over a long period of time.

  It is preferable that polyacrylic acid is 5-60 mass% with respect to the said binder component and the total amount of polyacrylic acid. If it is less than 5% by mass, the resulting coating film tends not to exhibit antifogging properties, or sufficient antifogging properties tend not to be obtained. If it exceeds 60% by mass, polyacrylic acids cannot be immobilized in the resulting coating, and the polyacrylic acids tend to elute upon water absorption. From the viewpoint of antifogging properties and immobilization of polyacrylic acids, the amount is more preferably 10 to 50% by mass, and still more preferably 20 to 40% by mass.

As the binder component, a silicon compound B represented by the following general formula [2], a compound C in which the silicon compound B is partially condensed, or a mixture of the above B and C can be used.
R ² _n SiY _4-n [2]
In the formula [2], R ² is at least one selected from the group consisting of a hydrocarbon group having 1 to 18 carbon atoms, or a partial hydrogen atom of the hydrocarbon group, an epoxy group, a glycidoxy group, and an amino group. An organic group substituted with a group. Y is at least one group selected from the group consisting of an alkoxy group, a chloro group, an isocyanate group, and a hydroxy group, and n is an integer of 0 to 3.

  Examples of the silicon compound B include methoxytrimethylsilane, ethoxytriethylsilane, (chloromethyl) dimethylisopropoxysilane, [bicyclo [2.2.1] hept-5-en-2-yl] triethoxysilane, and trimethyl [ 3- (triethoxysilyl) propyl] ammonium chloride, trimethoxy [3- (phenylamino) propyl] silane, trimethoxysilane, trimethoxyphenylsilane, trimethoxy (propyl) silane, trimethoxy (p-tolyl) silane, trimethoxy (methyl) ) Silane, triethoxysilane, triethoxyphenylsilane, triethoxymethylsilane, triethoxyfluorosilane, triethoxyethylsilane, triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octy Silane, pentyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, N- [2- (N-vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane hydrochloride, n-octyltriethoxysilane, n -Dodecyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, ethyltrimethoxysilane, dodecyltrimethoxysilane, cyclohexyltrimethoxysilane, bis [3- (trimethoxysilyl) propyl] amine, benzyltriethoxysilane, 3 -Ureidopropyltriethoxysilane, 3-trimethoxysilylpropyl chloride, 3-glycidyloxypropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-aminopropyl Trimethoxysilane, 3-aminopropyltriethoxysilane, 3- (triethoxysilyl) propyl isocyanate, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propyltriethoxysilane 2-cyanoethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 1- [3- (trimethoxysilyl) propyl] urea, 1,2-bis (trimethoxysilyl) ethane, Chloromethyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane, (3-mercaptopropyl) triethoxysilane, (3-bromopropyl) trimethoxysilane, orthosilicate tetrapropyl, orthosilicate tetramethyl, ortho Tetrakis silicate (1,1 1,3,3,3-hexafluoroisopropyl), tetraisopropyl orthosilicate, tetraethyl orthosilicate, tetrabutyl orthosilicate, dimethoxymethylphenylsilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, dimethoxydi-p-tolylsilane, dimethoxy ( Methyl) silane, diethoxymethylsilane, diethoxydiphenylsilane, diethoxydimethylsilane, diethoxy (methyl) phenylsilane, diethoxy (3-glycidyloxypropyl) methylsilane, cyclohexyl (dimethoxy) methylsilane, 3-mercaptopropyl (dimethoxy) methylsilane 3-glycidyloxypropyl (dimethoxy) methylsilane, 3-chloropropyldimethoxymethylsilane, 3-aminopropyldiethoxy Tylsilane, 3- (2-aminoethylamino) propyldimethoxymethylsilane, 1,5-dichloro-1,1,3,3,5,5-hexamethyltrisiloxane, 1,3-dimethoxy-1,1,3 , 3-tetraphenyldisiloxane, 1,3-dichloro-1,1,3,3-tetramethyldisiloxane, 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane, 1,1, 3,3,5,5,5-heptamethyl-3- (3-glycidyloxypropyl) trisiloxane, 3-chloropropyldichloromethylsilane, chloromethyl (dichloro) methylsilane, di-tert-butyldichlorosilane, dibutyldichlorosilane , Dichloro (methyl) octadecylsilane, dichloro (methyl) phenylsilane, dichlorocyclohexylmethyl Silane, dichlorodecylmethylsilane, dichlorodiethylsilane, dichlorodihexylsilane, dichlorodiisopropylsilane, dichlorodimethylsilane, dichlorodipentylsilane, dichlorodiphenylsilane, dichlorododecylmethylsilane, dichloroethylsilane, dichloromethylsilane, dichloromethylsilane, n -Octylmethyldichlorosilane, tetrachlorosilane, 1,2-bis (trichlorosilyl) ethane, 3-chloropropyltrichlorosilane, bis (trichlorosilyl) acetylene, butyltrichlorosilane, cyclohexyltrichlorosilane, decyltrichlorosilane, dodecyltrichlorosilane, Ethyltrichlorosilane, hexachlorodisilane, 1,1,2,2-tetrachloro-1,2-dimethyldisila , Isobutyltrichlorosilane, n-octyltrichlorosilane, phenyltrichlorosilane, texyltrichlorosilane, trichloro (methyl) silane, trichloro (propyl) silane, trichloro-2-cyanoethylsilane, trichlorohexylsilane, trichlorooctadecylsilane, trichlorosilane, Trichlorotetradecylsilane, (3-cyanopropyl) dimethylchlorosilane, (bromomethyl) chlorodimethylsilane, (chloromethyl) dimethylchlorosilane, 1,2-dichlorotetramethyldisilane, 1,3-dichloro-1,1,3,3 -Tetramethyldisiloxane, 1,5-dichloro-1,1,3,3,5,5-hexamethyltrisiloxane, α- (chlorodimethylsilyl) cumene, benzylchlorodimethylsilane, Chlorochlorodimethylsilane, chloro (decyl) dimethylsilane, chloro (dodecyl) dimethylsilane, chlorodiisopropylsilane, chlorodimethylphenylsilane, chlorodimethylpropylsilane, chlorodimethylsilane, chlorotriethylsilane, chlorotrimethylsilane, diethylisopropylsilyl chloride, Examples include dimethyl-n-octylchlorosilane, dimethylethylchlorosilane, dimethylisopropylchlorosilane, diphenylmethylchlorosilane, pentafluorophenyldimethylchlorosilane, tert-butyldimethylchlorosilane, tert-butyldiphenylchlorosilane, triisopropylsilyl chloride, and triphenylchlorosilane.

As polyacrylic acids,
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or polymethacrylic acid ester, and
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or a compound in which a part of hydrogen atoms of the methylene chain of polymethacrylic acid ester is substituted with an epoxy group, a glycidoxy group, or a substituent having reactivity with an amino group At least one selected from the group consisting of can be used.

式［３］中、反応性基Ｚはアミノ基、水酸基、エポキシ基、メルカプト基、イソシアナート基、アルコキシ基、ビニル基、アクリル基、もしくはメタクリル基などであり、ｓは１０〜３５０、ｔは５〜２００であることが好ましい。 Examples of the reactive substituent include an amino group, a hydroxyl group, an epoxy group, a mercapto group, an isocyanate group, an alkoxy group, a vinyl group, an acrylic group, and a methacryl group. Moreover, as polyacrylic acid, the compound which the site | part which has polyacrylic acid and the reactive group Z as shown by following General formula [3] copolymerized may be sufficient.

In the formula [3], the reactive group Z is an amino group, a hydroxyl group, an epoxy group, a mercapto group, an isocyanate group, an alkoxy group, a vinyl group, an acrylic group, or a methacryl group, s is 10 to 350, t is It is preferable that it is 5-200.

  The compound of the general formula [3] may be a block copolymer, an alternating copolymer, or a random copolymer. Moreover, s and t represent the number of each repeating unit in the case of a block copolymer, and represent the total number of each structural unit in the case of an alternating copolymer and a random copolymer.

  Examples of polyacrylic acids include polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate, sodium polyacrylate, acrylic acid-maleic acid copolymer salt, acrylic acid-sulfonic acid copolymer salt And a cross-linked product of neutralized polyacrylic acid and a self-crosslinked polyacrylic acid neutralized product.

  From the viewpoint of water absorption performance that contributes to antifogging properties, the acrylic acid is particularly preferably polyacrylic acid.

  In the step of preparing the coating agent for forming a film, the coating agent may contain a solvent. The solvent is not particularly limited as long as it dissolves the coating agent, and examples thereof include water, methyl alcohol, ethyl alcohol, propyl alcohol, butanol, ethylene glycol, 1,2-propanediol, and cyclohexanol. From the viewpoints of compatibility and safety, ethyl alcohol is preferred. Moreover, it is good also as a mixed solvent using a some solvent.

  In addition, a catalyst may be added to the coating agent for forming a film for the purpose of promoting the curing reaction of the coating agent. When an acidic aqueous solution is used as the catalyst, an aqueous solution having an acid catalyst such as an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, or an organic acid such as acetic acid, phthalic acid or succinic acid may be selected according to the hydrolysis rate. preferable. At this time, the acid catalyst is preferably added so that the pH value in the coating agent is 1 to 5.

  In addition, a metal complex such as tin, aluminum, titanium, or zirconium can be used as the catalyst. Here, the metal complex is preferably a fluoride, chloride, bromide, iodide, acetate, nitrate, sulfate, acetylacetonate salt or the like. The catalyst may be added in an amount up to 0.05 times by mass with respect to the amount of silicon compound B in the coating solution. Even if it exceeds 0.05 times the amount, there is a tendency that the catalytic effect with respect to the amount added does not further improve, so that it is not necessary to add a large amount of catalyst. On the other hand, in order to exert a catalytic effect, the curing catalyst is preferably added in an amount of 0.0001 times or more by mass ratio to the amount of silicon compound B in the treating agent.

  Further, the coating agent for forming a film includes a photopolymerization initiator, a thermal polymerization initiator, a surfactant, and a crosslinking agent as components other than the polyacrylic acids and the binder component as long as the object of the present invention is not impaired. Other components such as an antioxidant, an ultraviolet absorber, an infrared absorber, a flame retardant, a hydrolysis inhibitor, and an antifungal agent may be added.

  When the other component has a hydroxyl group, a carbonyl group, an amino group, a carboxyl group, a sulfo group, etc., the water absorption effect is promoted by the hydrophilicity of the component in addition to the water absorption effect by the component derived from the polyacrylic acid. Therefore, it is preferable.

  In the step of applying the coating agent for film formation, for example, with a known application means such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, flexographic printing, hand coating method, inkjet method, etc. A coating-forming coating agent can be applied on the primer layer formed on the substrate surface.

  As a method for curing the coating film of the coating agent for film formation, it can be cured by heat curing, photocuring or the like. In the case of thermosetting, the heating temperature is preferably 50 to 200 ° C, more preferably 80 to 150 ° C. If it is less than 50 degreeC, since a cure rate is slow and hardening takes time, it is unpreferable. Further, if it exceeds 200 ° C., polyacrylic acids are likely to deteriorate, which is not preferable. When photocuring, a general radical polymerization initiator or cationic polymerization initiator is used, and the light irradiation method is not particularly limited, and a high-pressure mercury lamp, a xenon lamp, or the like can be used.

  Further, in order to obtain a sufficient water absorbing function of the coating, it is preferable that the thickness of the coating is 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.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, quality evaluation was performed by the method shown below for the anti-fogging articles obtained in the present examples and comparative examples.

[Measurement of water absorption per unit volume of coating]
The mass (a) of the antifogging article after being kept in a drying furnace at a temperature of 80 ° C. for 2 hours is measured, and 35 ° C. saturated water vapor is brought into contact with the coating until the entire exposed surface becomes cloudy. After wiping, the mass (b) of the antifogging article was measured. The amount of water absorption per unit volume was the value obtained by the formula {(b−a) / (steam exposure area × film thickness)} as the water absorption per unit volume. The value (a) here corresponds to that in a state in which the film does not absorb water. A sample having a water absorption of 0.05 to ³ mg / mm ³ was designated as (◯), and a sample outside the range was designated as (×).

[Film thickness measurement]
Using a stylus type surface roughness meter (manufactured by Kosaka Laboratory, Surfcorder ET-4000A), the film thickness of the coating formed on the substrate was measured.

[35 ° C water vapor defogging test]
At the top of the tank filled with 35 ° C. saturated steam, the sample is placed with the coating surface facing the tank, and the time until cloudiness occurs is measured. (X) is a case where a problem occurred in appearance or in appearance.

[Real car anti-fogging test]
As shown in FIG. 1, a sample is installed between two chambers using a two-chamber environmental tester (model TBL-2HW2P1A / TBU-2HW0P2A manufactured by Tabai Espec), and the temperature and humidity of the two chambers are close to actual use. The time until dew condensation occurred was measured under the following conditions, and those with 10 minutes or more were (O) and those with less than 10 minutes were (X).
Condition 1: Assumed rainy season Assumed temperature outside the vehicle 20 ° C, assumed temperature inside the vehicle 25 ° C, assumed humidity inside the vehicle 95%
Condition 2: Assuming winter season The assumed constant temperature outside the vehicle is 0 ° C, the assumed constant temperature inside the vehicle is 25 ° C, and the assumed constant temperature inside the vehicle is 60%

[Heat resistance test]
A sample held for 200 hours in a constant temperature bath held at 100 ° C., with no defects in appearance, and those that passed the anti-fogging property (35 ° C. water vapor anti-fogging property, actual vehicle anti-fogging property) test (○) The case where the appearance was defective or the case where the anti-fogging property was rejected was defined as (x).

[Adhesion evaluation]
After immersing the anti-fogging article in warm water at 40 ° C. for 24 hours, a cross-cut test was performed, and (◯) indicates that no peeling occurred and (×) indicates that peeling occurred.

Example 1
[Preparation of substrate]
As the substrate, a float glass having a thickness of 3 mm and 100 mm square was used. The surface of the substrate glass was polished with ceria fine particles, washed by brushing and dried.

[Formation of primer layer]
1N nitric acid (reagent, manufactured by Kishida Chemical Co., Ltd.) mixed with 1 g of 3-aminopropyltriethoxysilane (KBM-903, manufactured by Shin-Etsu Silicone) as a silicon compound A and 98 g of modified alcohol (Echinen F-1, manufactured by Kishida Chemical Co., Ltd.) Was added to prepare a primer coating solution. This primer coating solution is moistened with a wiper made of cellulose fiber (trade name “Bencot”, model M-1, 50 mm × 50 mm, manufactured by Ozu Sangyo), applied to the surface of the float glass substrate, dried and then wiped dry to apply the primer. A prepared substrate was prepared.

[Preparation of antifogging film-forming coating agent]
41.53 g of methyl alcohol, 10.14 g of ion-exchanged water, and 10 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 25,000 were added and mixed with stirring until dissolved. Thereafter, 12.72 g of 3-glycidoxypropyltrimethoxysilane (hereinafter referred to as GPTMS) (manufactured by Shin-Etsu Silicone, trade name: KBE-403), methyltriethoxysilane (hereinafter referred to as MTES) (Shin-Etsu Silicone) Product, product name: KBE-13) 15.48 g, 10.14 g of 1N nitric acid was added, and the mixture was stirred at 23 ° C. for 16 hours to obtain 100 g of a heat-resistant antifogging film-forming coating agent.

[Formation of anti-fogging film]
The coating agent was applied on the primer layer of the base glass by a spin coating method. The base glass on which the coating agent was applied was placed in an electric furnace maintained at 100 ° C. for 16 hours and cured to form an antifogging film to obtain an antifogging article. Table 1 shows the quality evaluation results. In the film of this antifogging article, the film thickness is 35 μm, the water absorption of the unit volume of the film is ○ at 0.7 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ○ at 120 seconds, assuming anti-fogging on actual vehicles The property test was ◯ for 60 minutes or more under condition 1, ◯ in condition 2 and ◯ at 21 minutes, adhesion did not peel, and the appearance and antifogging property did not change even after the heat test.

Example 2
An antifogging article is obtained in the same manner as in Example 1 except that the silicon compound A of Example 1 is changed from 3-aminopropyltriethoxysilane to 3-mercaptopropyltrimethoxysilane (KBM-803, manufactured by Shin-Etsu Silicone). It was. In the film of this antifogging article, the film thickness is 35 μm, the water absorption of the unit volume of the film is ○ at 0.7 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ○ at 120 seconds, assuming anti-fogging on actual vehicles. The property test was ◯ for 60 minutes or more under condition 1, ◯ in condition 2 and ◯ at 21 minutes, adhesion did not peel, and the appearance and antifogging property did not change even after the heat test.

Example 3
In Example 1 [Preparation of coating agent for forming anti-fogging film], except that MTES of 15.48 g was changed to 20.78 g of tetraethoxysilane (hereinafter referred to as TEOS), it was the same as Example 1. An antifogging article was obtained by the operation. In the film of this antifogging article, the film thickness is 35 μm, the water absorption amount of the unit volume of the film is 0.2 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ○ in 40 seconds. The property test was 45 minutes under condition 1, ○ under condition 2, ○ after 15 minutes, adhesion did not peel, and the appearance and antifogging property did not change even after the heat test.

Comparative Example 1
In Example 1, an antifogging article was obtained by the same operation as in Example 1 except that the primer layer was not formed. In the film of this antifogging article, the film thickness is 35 μm, the water absorption of the unit volume of the film is ○ at 0.7 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ○ at 120 seconds, assuming anti-fogging on an actual vehicle. In the property test, the condition 1 was 60 minutes or more, ○, in the condition 2, ○ in 21 minutes, the adhesion was peeled, and the appearance and antifogging property were unchanged after the heat test.

Comparative Example 2
Similar to Example 1 except that 10 g of polyvinyl alcohol (made by Kishida Chemical Co., Ltd.) having a molecular weight of 2,000 was used in place of 10 g of polyacrylic acid in “Preparation of antifogging film-forming coating agent” in Example 1. The anti-fogging article was obtained by the operation. In the film of this antifogging article, the film thickness is 35 μm, the water absorption amount of the unit volume of the film is ◯ at 1.0 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ◯ at 150 seconds. In the property test, the condition 1 was 60 minutes or more, ○ in the condition 2, ○ in 30 minutes, the adhesion was not peeled, ○, and the film was yellowed after the heat test.

Comparative Example 3
An antifogging article was obtained in the same manner as in Example 1 except that polyvinyl acetal having a degree of acetalization of 9% (KX-1, solid content 9%, manufactured by Sekisui Chemical Co., Ltd.) was used as a coating agent for forming an antifogging film. In the film of this antifogging article, the film thickness is 10 μm, the water absorption of the unit volume of the film is ○ at 1.5 mg / mm ³ , and the 35 ° C. water vapor antifogging property is ○ at 60 seconds. In the property test, the condition 1 was 50 minutes, and in the condition 2, it was ○ in 18 minutes, the adhesion was not peeled, and the film was yellowed after the heat test.

1 Assumed temperature outside the vehicle (temperature control)
2 Assumed constant temperature chamber (temperature / humidity control)
3 Wall material that separates vehicle exterior and vehicle interior 4 Anti-fogging article 5 Base material 6 Coating

Claims (9)

An anti-fogging article comprising: a base material; a film containing a binder component and a polyacrylic acid copolymer; and a primer layer between the base material and the film. The anti-fogging article according to claim 1, wherein the primer layer comprises a hydrolysis product of a silicon compound A represented by the following general formula [1].
R ¹ _m SiX _4-m [1]
(In the formula [1], R ¹ is an organic group containing at least one group selected from the group consisting of an amino group, a glycidoxy group, and a mercapto group, and X is an alkoxy group having 1 to 18 carbon atoms, m is an integer of 1 to 3.) The binder component is a silicon compound B represented by the following general formula [2], a compound C in which the silicon compound B is partially condensed, or a mixture of B and C. The antifogging article according to 1 or 2.
R ² _n SiY _4-n [2]
(In the formula [2], R ² is at least 1 selected from the group consisting of a hydrocarbon group having 1 to 18 carbon atoms, or a partial hydrogen atom of the hydrocarbon group, an epoxy group, a glycidoxy group, and an amino group. (Y is at least one group selected from the group consisting of an alkoxy group, a chloro group, an isocyanate group, and a hydroxy group, and n is an integer of 0 to 3). The anti-fogging article according to any one of claims 1 to 3, wherein the polyacrylic acid has a molecular weight of 1,000 to 250,000. The polyacrylic acids are
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or polymethacrylic acid ester, and
Polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, or a compound in which a part of hydrogen atoms of the methylene chain of polymethacrylic acid ester is substituted with an epoxy group, a glycidoxy group, or a substituent having reactivity with an amino group The antifogging article according to any one of claims 1 to 4, wherein the antifogging article is at least one selected from the group consisting of: The antifogging article according to any one of claims 1 to 5, wherein the polyacrylic acid is 5 to 60% by mass based on the total amount of the binder component and the polyacrylic acid. The antifogging article according to any one of claims 1 to 6, wherein the article has heat resistance against heat of 100 ° C or less. Water absorption of the coating is performed by a component derived from polyacrylic acid present in the coating, and the water absorption of the unit volume at the time of water absorption saturation of the coating is 0.05 to ³ mg / mm ^3. Item 8. The antifogging article according to any one of Items 1 to 7. The method for forming an antifogging article according to any one of claims 1 to 8, wherein the antifogging article is produced through at least the following steps.
(1) A step of forming a primer layer comprising a hydrolysis product of the silicon compound A on the surface of the substrate (2) A step of preparing a coating agent for forming a film containing a binder component and polyacrylic acids (3) The coating A step of applying a coating agent for forming, and a step of (4) curing the coating film.

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