JP2012148436A - Low reflection material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low reflection material having superior antifogging properties with hardly decreasing the low reflection that low reflection material originally has.SOLUTION: The low reflection material has a base material, a low refractive index material layer being formed on the surface of the base material, a surface layer formed on the low refractive index material layer, wherein the surface layer has the repeating unit which is represented by formula (I), and is formed with the (meta)acrylic polymer, which has the alkoxysilyl group at least in the leaf terminal.

Description

  The present invention relates to a low reflective material. More specifically, the present invention relates to a low-reflective material having excellent antifogging properties. The low-reflective material of the present invention is expected to be used in a wide range of applications such as rear-view mirrors for automobiles and motorcycles, display devices such as displays, optical filters, solar cells, and the like.

  In general, a low-reflective material having a low-refractive index material layer is used for automobile rearview mirrors or the like in order to improve visibility (see, for example, Patent Documents 1 to 4). However, since the surface of the low-reflective material is inferior in hydrophilicity, the visibility is lowered when the surface of the low-reflective material is clouded under high humidity or when water droplets adhere to the surface of the low-reflective material. Sometimes.

  As a polymer for imparting hydrophilicity to a base material, for example, a hydrophilic graft polymer in which a hydrophilic acrylamide polymer is used for a graft side chain of a copolymer of (meth) acrylate and acrylamide is known (for example, , See Patent Document 5). Also, as a hydrophilic layer that can be easily fixed to the surface of a hydrophobic resin substrate, a hydrophilic layer obtained by applying a mixture of hydrophilic silica and titanium oxide to a film substrate and drying it. Has been proposed (see, for example, Patent Document 6). However, both the hydrophilic graft polymer and the hydrophilic layer have the disadvantage that the low reflectivity inherent in the low reflectivity material is impaired.

  In addition, applying a surfactant to the surface of a base material in order to impart antifogging properties to the surface of the base material has been widely performed (see, for example, Patent Document 7 and Patent Document 8). However, since the surfactant dissolves in moisture when moisture adheres to the surface of the substrate, it may be detached from the surface of the substrate.

JP 09-099453 A JP-A-11-072604 International Publication No. 2008/038714 Pamphlet Special table 2008-517867 JP 2002-308950 A JP 2006-231890 A Japanese Patent Laid-Open No. 02-016185 JP 2003-238207 A

  This invention is made | formed in view of the said prior art, and provides the low-reflective material to which anti-fogging property was provided, without substantially reducing the low-reflective property which low-reflective material originally has. For the purpose.

The present invention
[1] A base material, a low refractive index material layer formed on the surface of the base material, and a surface layer formed on the low refractive index material layer, wherein the surface layer is represented by the formula (I ):

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrophilic group)
Having a repeating unit represented by formula (II) at least at one end:

(In the formula, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and among R ³ , R ⁴ and R ⁵ , At least one group of C 1-4 is an alkoxy group, and R ⁶ is an alkylene group of 1-12 carbon atoms)
A low-reflective material characterized by being formed of a (meth) acrylic polymer having an alkoxysilyl group represented by:
[2] In formula (I), R ² is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms having at least one hydroxyl group, and a carbon atom having 1 hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end. A polyethylene glycol group having ˜20, a polypropylene glycol group having 1 to 10 carbon atoms having a hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end, the formula (III):

(Wherein R ⁷ and R ⁸ are each independently an alkylene group having 1 to 4 carbon atoms, and R ⁹ and R ¹⁰ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)
Or a group represented by formula (IV):

Wherein R ¹¹ is an alkylene group having 1 to 4 carbon atoms, R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹⁴ is an organic group, and X ⁻ is an anion. Show)
The low reflective material according to [1], which is a group represented by:
[3] The low reflective material according to [1] or [2], wherein the number of repeating units represented by the formula (I) is 1-1000,
[4] The low reflective material layer according to any one of [1] to [3], wherein the low refractive index material layer is formed of metal fluoride fine particles, silicon dioxide fine particles, or tin oxide fine particles, and [5] Formula (I):

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrophilic group)
Having a repeating unit represented by formula (II) at least at one end:

(In the formula, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and among R ³ , R ⁴ and R ⁵ , At least one group of C 1-4 is an alkoxy group, and R ⁶ is an alkylene group of 1-12 carbon atoms)
And a (meth) acrylic polymer for a low-reflective material, characterized by having an alkoxysilyl group represented by the formula:

  ADVANTAGE OF THE INVENTION According to this invention, the low-reflective material to which antifogging property was provided is provided, substantially reducing the low-reflective property which low-reflective material originally has.

  As described above, the low reflective material of the present invention comprises a base material, a low refractive index material layer formed on the surface of the base material, and a surface layer formed on the low refractive index material layer. The surface layer has the formula (I):

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrophilic group)
Having a repeating unit represented by formula (II) at least at one end:

(In the formula, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and among R ³ , R ⁴ and R ⁵ , At least one group of C 1-4 is an alkoxy group, and R ⁶ is an alkylene group of 1-12 carbon atoms)
It is formed by the (meth) acrylic-type polymer which has the alkoxy silyl group represented by these.

  Since the low-reflective material of the present invention uses the (meth) acrylic polymer for the surface layer, the anti-fogging is excellent without substantially reducing the low reflectivity inherent in the low-reflective material. Have sex. The (meth) acrylic polymer is useful as a (meth) acrylic polymer for low-reflective materials.

  Examples of the material of the base material used for the low-reflective material of the present invention include, for example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyamide represented by nylon, polyimide, polyurethane, urea resin, polylactic acid, polyvinyl alcohol, poly Examples include vinyl acetate, acrylic resin, polyester, polysulfone, polycarbonate, ABS resin, AS resin, silicone resin, glass, ceramic, metal, and the like, but the present invention is not limited to such examples.

  The shape of the substrate is not particularly limited, and examples thereof include a film, a sheet, a plate, a rod, and a molded body formed into a predetermined shape. However, the present invention is not limited only to such illustration.

  As the low refractive material layer formed on the surface of the substrate, one having an antireflection effect is used. The low refractive material layer can be formed using, for example, a low refractive material containing fine particles having a low refractive index and a resin binder.

  The refractive index of the fine particles having a low refractive index is preferably 1.5 or less, more preferably 1.4 or less, from the viewpoint of sufficiently reducing the refractive index. Examples of the fine particles having a low refractive index include metal fluoride fine particles, silicon dioxide fine particles, and tin oxide fine particles. Examples of the material for the metal fluoride fine particles include magnesium fluoride, aluminum fluoride, calcium fluoride, lithium fluoride, and the like, but the present invention is not limited to such examples. Among the fine particles having a low refractive index, metal fluoride fine particles are preferable, and magnesium fluoride fine particles are more preferable from the viewpoint of improving adhesion to the surface layer.

  Examples of the shape of the fine particles having a low refractive index include a spherical shape, an elliptical spherical shape, a cubic shape, a rectangular parallelepiped shape, a columnar shape, a needle shape, a plate shape, and a flake shape, but the present invention is limited only to such illustrations. Is not to be done. The average particle size of the fine particles having a low refractive index is usually preferably 1 nm or more, more preferably 10 nm or more from the viewpoint of dispersion stability, and preferably 100 nm or less, more preferably 50 nm or less from the viewpoint of transparency. It is. In addition, the average particle diameter of the fine particles having a low refractive index is a value when measured with a laser diffraction particle size distribution analyzer [manufactured by Shimadzu Corporation, product number: SLDA7000].

  A resin binder that can uniformly disperse fine particles having a low refractive index and is excellent in film formability and adhesion to a substrate is preferable. Examples of the resin binder include acrylic resins, polyester resins, olefin resins such as polyethylene and polypropylene, styrene resins, amide resins, imide resins, vinyl chloride resins, polyvinyl alcohol, polyvinyl butyral, and polycarbonate. However, the present invention is not limited to such examples.

  The amount of the resin binder is preferably 10 to 300 parts by mass, more preferably 30 to 200 parts by mass, per 100 parts by mass of the fine particles having a low refractive index, from the viewpoint of dispersion stability of the fine particles having a low refractive index.

  As a method for forming a low refractive material layer on the surface of the substrate, for example, a method of mixing fine particles having a low refractive index, a resin binder and an organic solvent, and applying the obtained mixture onto the surface of the substrate Etc.

  Examples of the organic solvent include alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbon compounds; aromatics such as toluene and xylene Although a hydrocarbon compound etc. are mentioned, this invention is not limited only to this illustration. These organic solvents may be used alone or in combination of two or more. The organic solvent is usually appropriately selected according to the type of the resin binder, and those suitable for the resin binder are used.

  The amount of the organic solvent is preferably adjusted so that the solid content in the mixture is 5 to 50% by mass from the viewpoint of dispersion stability and coatability, and is 10 to 40% by mass. It is more preferable to adjust so.

  Examples of the method for applying the mixture to the substrate include a flow coating method, a spray coating method, a dipping method, a brush coating method, and a roll coating method, but the present invention is limited to such examples only. is not.

  After the mixture is applied to the substrate, the low refractive material layer can be formed by drying in a conventional manner and removing the organic solvent contained in the mixture.

  The thickness (thickness after drying) of the low refractive material layer formed on the surface of the substrate is preferably about 10 to 200 nm from the viewpoint of antireflection properties.

  As described above, after the low refractive material layer is formed on the surface of the substrate, the surface layer is formed on the low refractive material layer, whereby the low reflective material of the present invention is obtained.

  As described above, the surface layer is formed of a (meth) acrylic polymer having a repeating unit represented by the formula (I) and having an alkoxysilyl group represented by the formula (II) at least at one end.

In the repeating unit represented by the formula (I), R ¹ is a hydrogen atom or a methyl group.
R ² is a hydrophilic group. Examples of R ² include a hydrogen atom and an alkyl group having 1 to 4 carbon atoms having at least one hydroxyl group, and a polyethylene glycol group having 1 to 20 carbon atoms having a hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end. , A polypropylene glycol group having 1 to 10 carbon atoms having a hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end, Formula (III):

(Wherein R ⁷ and R ⁸ are each independently an alkylene group having 1 to 4 carbon atoms, and R ⁹ and R ¹⁰ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)
A group represented by formula (IV):

Wherein R ¹¹ is an alkylene group having 1 to 4 carbon atoms, R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹⁴ is an organic group, and X ⁻ is an anion. Show)
Although the group etc. which are represented by these are mentioned, this invention is not limited only to this illustration. Among these groups, the group represented by the formula (III) is preferable from the viewpoint of increasing the coating film strength.

In the formula (III), R ⁷ and R ⁸ are each independently an alkylene group having 1 to 4 carbon atoms. R ⁷ is preferably a methylene group, an ethylene group, an n-propylene group or an isopropylene group, more preferably a methylene group or an ethylene group. R ⁸ is preferably a methylene group or an ethylene group. R ⁹ and R ¹⁰ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the formula (IV), R ¹¹ is an alkylene group having 1 to 4 carbon atoms. R ¹¹ is preferably a methylene group, an ethylene group, an n-propylene group or an isopropylene group, more preferably a methylene group or an ethylene group. R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ¹⁴ is an organic group. Specific examples of the organic group include an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 12 carbon atoms, and a carboxyalkyl group having 2 to 6 carbon atoms. However, the present invention is limited only to such examples. Is not to be done. X ⁻ is an anion. X ^- is a suitable example of an alkyl chloride ion having 1 to 4 carbon atoms, a monovalent dialkyl sulfate ion carbon atoms in the alkyl group is 1-4, 6 to 8 carbon atoms aryl chloride ions, carbon atoms in the alkyl group Alkyl sulfate halides having 1 to 4 numbers, halogen ions, acetate ions, borate ions, citrate ions, tartaric acid ions, hydrogen sulfate ions, bisulfite ions, sulfate ions, phosphate ions, etc. may be mentioned. However, the present invention is not limited to such examples. Examples of the halogen atom in the halide include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the halogen atom in the halogen ion include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among X ⁻ , alkyl chloride ions having 1 to 4 carbon atoms, monovalent dialkyl sulfate ions having 1 to 4 carbon atoms in the alkyl group, and aryl chloride ions having 6 to 8 carbon atoms are preferable.

  From the viewpoint of imparting hydrophilicity to the substrate surface, the lower limit of the number of repeating units represented by formula (I) is preferably 1 or more, more preferably 10 or more, and the repeating units represented by formula (I). The upper limit of the number is preferably 1000 or less, more preferably 500 or less.

In the alkoxysilyl group represented by the formula (II), R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and R ³ , R ⁴ and R ⁵ are each an alkoxy group having 1 to 4 carbon atoms. The reason why at least one of R ³ , R ⁴ and R ⁵ is an alkoxy group having 1 to 4 carbon atoms is to fix the surface layer to the low refractive material layer by chemical bonding. Thus, R ^3, it is preferable that at least one of the radicals R ⁴ and R ⁵ is an alkoxy group having 1 to 4 carbon atoms, R ^3, R ⁴ and at least two groups having a carbon number of R ⁵ more preferably 1 to 4 alkoxy group, more preferably any of R ^3, R ⁴ and R ⁵ is an alkoxy group having 1 to 4 carbon atoms. Among the alkyl groups having 1 to 4 carbon atoms, a methyl group and an ethyl group are preferable, and a methyl group is more preferable. Among the alkoxy groups having 1 to 4 carbon atoms, a methoxy group and an ethoxy group are preferable, and a methoxy group is more preferable.

In the alkoxysilyl group represented by the formula (II), R ⁶ is an alkylene group having 1 to 12 carbon atoms. Among R ⁶ , an alkylene group having 1 to 6 carbon atoms is preferable, and an alkylene group having 2 to 6 carbon atoms is more preferable.

  The alkoxysilyl group represented by the formula (II) is present at least at one end of the (meth) acrylic polymer, but the (meth) acrylic polymer is used from the viewpoint of sufficiently expressing the properties of the (meth) acrylic polymer. It is preferable that it exists only in the one terminal. In the case where the alkoxysilyl group represented by the formula (II) is present only at one end of the (meth) acrylic polymer, from the viewpoint of sufficiently expressing the properties of the (meth) acrylic polymer at the other end, For example, it is preferable that a group such as a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a residue of a polymerization initiator is present.

  A (meth) acrylic polymer having a repeating unit represented by the formula (I) and having an alkoxysilyl group represented by the formula (II) at least at one end is, for example, the formula (V):

(Wherein R ¹ and R ² are the same as above)
A (meth) acrylic monomer represented by formula (VI):

(Wherein R ³ , R ⁴ , R ⁵ and R ⁶ are the same as above)
It can prepare by polymerizing in presence of the alkoxysilyl group containing compound represented by these.

  Examples of the (meth) acrylic monomer represented by the formula (V) include a methyl chloride salt of N, N-dimethylaminoethyl (meth) acrylate, a dimethyl sulfate salt of N, N-dimethylaminoethyl (meth) acrylate, Diethyl sulfate of N, N-dimethylaminoethyl (meth) acrylate, benzyl chloride salt of N, N-dimethylaminoethyl (meth) acrylate, methyl chloride salt of N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate dimethyl sulfate, N, N-dimethylaminopropyl (meth) acrylate diethyl sulfate, N, N-dimethylaminopropyl (meth) acrylate benzyl chloride salt, N, N- Diethylaminoethyl (meth) acrylate Methyl chloride salt, dimethyl sulfate salt of N, N-diethylaminoethyl (meth) acrylate, diethyl sulfate salt of N, N-diethylaminoethyl (meth) acrylate, benzyl chloride salt of N, N-diethylaminoethyl (meth) acrylate, N , N-diethylaminopropyl (meth) acrylate methyl chloride salt, N, N-diethylaminopropyl (meth) acrylate dimethyl sulfate, N, N-diethylaminopropyl (meth) acrylate diethyl sulfate, N, N-diethylaminopropyl (Meth) acrylate, N- (meth) acryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine, N- (meth) acryloylaminoethyl-N, N-dimethylammonium-α-N-methyl Carboxymethyl betaine, methoxy triethylene glycol (meth) acrylate, 2,2,2 although such trifluoroethyl methacrylate, the invention is not limited only to those exemplified. These (meth) acrylic monomers may be used alone or in combination of two or more. Among these (meth) acrylic monomers, the methyl chloride salt of N, N-dimethylaminoethyl (meth) acrylate and N, N-dimethylaminoethyl (meth) acrylate can be easily obtained at low cost. Of these, diethyl sulfate is preferred. N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine is, for example, disclosed in JP-A-9-95474, JP-A-9-95586, and JP-A-11-222470. Can be easily prepared with high purity.

  Examples of the alkoxysilyl group-containing compound represented by the formula (VI) include 1-thiopropyl-3-trimethoxysilane, 1-thiopropyl-3-triethoxysilane, 1-thiopropyl-3-triisopropoxysilane, Examples include thiopropyl-3-methyldimethoxysilane, 1-thiopropyl-3-methyldiethoxysilane, 1-thiopropyl-3-methyldipropoxysilane, and the like, but the present invention is not limited to such examples. These alkoxysilyl group-containing compounds may be used alone or in combination of two or more.

  The amount of the alkoxysilyl group-containing compound represented by the formula (VI) is not particularly limited, but it is usually preferably about 0.01 to 10 parts by weight per 100 parts by weight of the total amount of monomers to be subjected to polymerization.

  Note that the (meth) acrylic monomer represented by the formula (V) may be used in combination with another polymerizable monomer as long as the object of the present invention is not inhibited.

  Examples of other polymerizable monomers include styrene, α-hydroxystyrene, p-hydroxystyrene, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic acid. Isobutyl, tert-butyl (meth) acrylate, neopentyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic Stearyl acid, cetyl (meth) acrylate, ethyl carbitol (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, methoxyethyl (meth) acrylate , Methoxybutyl (meth) acrylate, N-methyl (meth) acrylamide, N-ethyl (meth) acrylate Luamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-octyl (meth) acrylamide, N, N-dimethyl (Meth) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, diacetone (meth) acrylamide, styrene, methyl itaconate, ethyl itaconate, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, N -Vinylcaprolactam etc. are mentioned, However, this invention is not limited only to this illustration. These other polymerizable monomers may be used alone or in combination of two or more.

  When the (meth) acrylic monomer represented by the formula (V) is polymerized in the presence of the alkoxysilyl group-containing compound represented by the formula (VI), it is preferable to use a polymerization initiator.

  Examples of the polymerization initiator include azoisobutyronitrile, methyl azoisobutyrate, azobisdimethylvaleronitrile, benzoyl peroxide, potassium persulfate, ammonium persulfate, benzophenone derivatives, phosphine oxide derivatives, benzoketone derivatives, phenylthioether derivatives, azides Derivatives, diazo derivatives, disulfide derivatives and the like can be mentioned, but the present invention is not limited to such examples. These polymerization initiators may be used alone or in combination of two or more.

  The amount of the polymerization initiator is not particularly limited, but is usually about 0.01 to 5 parts by weight per 100 parts by weight of the total amount of the monomer including the (meth) acrylic monomer represented by the formula (V). It is preferable.

  Examples of the method for polymerizing the (meth) acrylic monomer represented by the formula (V) include a solution polymerization method, but the present invention is not limited to such examples. When the (meth) acrylic monomer represented by the formula (V) is polymerized by a solution polymerization method, for example, the (meth) acrylic monomer represented by the formula (V) is dissolved in a solvent, and the resulting solution is Polymerization can be performed by adding a polymerization initiator while stirring.

  Examples of the solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene, and xylene. Examples include compounds, aliphatic hydrocarbon compounds such as n-hexane, alicyclic hydrocarbon compounds such as cyclohexane, and acetic acid esters such as methyl acetate and ethyl acetate. However, the present invention is limited only to such examples. is not. These solvents may be used alone or in combination of two or more.

  The amount of the solvent is such that the concentration of the monomer in the solution obtained by dissolving the monomer to be subjected to polymerization containing the (meth) acrylic monomer represented by the formula (V) in the solvent is about 10 to 80% by weight. It is preferable to adjust so that it becomes.

  The polymerization conditions such as polymerization temperature and polymerization time when polymerizing the (meth) acrylic monomer represented by the formula (V) depend on the type of monomer and the amount used, the type of polymerization initiator and the amount used. It is preferable to adjust appropriately.

  The atmosphere when the (meth) acrylic monomer represented by the formula (V) is polymerized is preferably an inert gas. Examples of the inert gas include nitrogen gas and argon gas, but the present invention is not limited to such examples.

  The completion of the polymerization reaction and the presence or absence of unreacted monomers in the reaction system can be confirmed by, for example, a general analysis method such as gas chromatography.

  A (meth) acrylic polymer having an alkoxysilyl group can be obtained by polymerizing the (meth) acrylic monomer represented by the formula (V) and other monomers used as necessary as described above.

  The viscosity average molecular weight of the (meth) acrylic polymer having an alkoxysilyl group is preferably 100 or more, more preferably 500 or more, and (meth) having an alkoxysilyl group from the viewpoint of sufficiently expressing the surface modification effect. From the viewpoint of increasing the solubility of the acrylic polymer, it is preferably 100,000 or less, more preferably 50,000 or less. The viscosity average molecular weight of the (meth) acrylic polymer having an alkoxysilyl group can be measured by, for example, gel permeation chromatography.

  The (meth) acrylic polymer having an alkoxysilyl group can be used after being dissolved in a solvent. Examples of the solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene, and xylene. Examples include compounds, aliphatic hydrocarbon compounds such as n-hexane, alicyclic hydrocarbon compounds such as cyclohexane, and acetic acid esters such as methyl acetate and ethyl acetate. However, the present invention is limited only to such examples. is not. These solvents may be used alone or in combination of two or more.

  The amount of the solvent is not particularly limited. Usually, the concentration of the (meth) acrylic polymer having an alkoxysilyl group in a solution obtained by dissolving the (meth) acrylic polymer having an alkoxysilyl group in the solvent is 10 to 10. It is preferable to adjust so that it may become about 80 weight%.

  The surface layer can be formed by applying a (meth) acrylic polymer having an alkoxysilyl group or a solution thereof on the low refractive index material layer of the substrate. Examples of a method for applying a (meth) acrylic polymer having an alkoxysilyl group or a solution thereof on the low refractive index material layer of the substrate include, for example, a flow coating method, a spray coating method, a dipping method, a brush coating method, and a roll coating. Although the law etc. are mentioned, this invention is not limited only to this illustration.

  The temperature at which the (meth) acrylic polymer having an alkoxysilyl group or a solution thereof is applied on the low refractive index material layer may be normal temperature or warming. Since the coating amount of the (meth) acrylic polymer having an alkoxysilyl group or a solution thereof varies depending on the use of the low-reflective material of the present invention and cannot be determined unconditionally, it is appropriately adjusted according to the use etc. It is preferable to do.

  After coating the (meth) acrylic polymer having an alkoxysilyl group or a solution thereof on the low refractive index material layer, it is preferable to heat the substrate from the viewpoint of increasing production efficiency. The temperature at which the substrate is heated varies depending on the heat-resistant temperature of the substrate and cannot be determined unconditionally. However, a temperature suitable for the substrate is usually selected within the range of 50 to 150 ° C. It is preferable to do.

  As described above, by applying the (meth) acrylic polymer having an alkoxysilyl group or a solution thereof on the low refractive index material layer formed on the surface of the substrate, the low refractive index material layer is formed. A low-reflective material in which a surface layer is formed can be manufactured.

  The thickness of the surface layer formed on the low-reflective material is preferably 5 nm or more, more preferably 10 nm or more from the viewpoint of improving antifogging properties, and preferably 100 nm or less from the viewpoint of improving low reflectivity. More preferably, it is 80 nm or less, More preferably, it is 60 nm or less.

  In the low reflective material of the present invention, since a surface layer made of a (meth) acrylic polymer having an alkoxysilyl group is formed on the low refractive index material layer, hydrophilicity can be imparted to the substrate, It is possible to prevent the water from being washed away when water adheres as in the case of using a conventional surfactant. Furthermore, since the low-reflective material of the present invention provides sufficient antifogging properties even when the surface layer is small, the thickness of the surface layer is the same as when a conventional hydrophilic graft polymer is used. Therefore, it is possible to prevent the low reflectivity from being impaired by increasing the thickness of the surface layer.

  Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Production Example 1
N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine [manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name] in a 500 mL Kolben equipped with a nitrogen gas inlet tube, a condenser and a stirrer : GLBT] 32.31 g, 3-mercaptopropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-803] 1.55 g and ethanol 146.20 g were added. After degassing by reducing the pressure inside the Kolben, nitrogen gas was introduced into the Kolben to return to normal pressure, and oxygen gas in the Kolben was eliminated as much as possible.

  Next, after heating the contents of Kolben to 65 ° C. with an oil bath provided in Kolben, 1.83 g of azobisisobutyronitrile is added, and the temperature of the contents of Kolben is maintained at 70 ° C. The mixture was aged for 4 hours. Thereafter, 0.37 g of azobisisobutyronitrile was further added to the Kolben, and a polymer solution was obtained by aging for 4 hours while maintaining the reaction temperature at 70 ° C.

  The obtained polymer solution was cooled to 30 ° C. in a water bath and diluted with 182.76 g of ethanol to obtain a (meth) acrylic polymer solution having an alkoxysilyl group.

  By measuring the viscosity of the obtained (meth) acrylic polymer solution having an alkoxysilyl group at 25 ° C. with an Ubbelohde viscometer [manufactured by Mutual Riken Glass Co., Ltd., product number: U-0327-26], When the viscosity average molecular weight was determined, the viscosity average molecular weight was 15,000.

Production Example 2
N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine [manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name] in a 500 mL Kolben equipped with a nitrogen gas inlet tube, a condenser and a stirrer : GLBT] 35.00 g, 3-mercaptopropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-803] 3.27 g and ethanol 153.10 g were added. After degassing by reducing the pressure inside the Kolben, nitrogen gas was introduced into the Kolben to return to normal pressure, and oxygen gas in the Kolben was eliminated as much as possible.

  Next, after the contents of Kolben are heated to 65 ° C. using an oil bath provided in Kolben, 0.38 g of azobisisobutyronitrile is added to keep the temperature of the Kolben contents at 70 ° C. The mixture was aged for 4 hours. Thereafter, 0.38 g of azobisisobutyronitrile was further added to the Kolben, and a polymer solution was obtained by aging for 4 hours while maintaining the reaction temperature at 70 ° C.

  The resulting polymer solution was cooled to 30 ° C. in a water bath and diluted with 191.37 g of ethanol to obtain a (meth) acrylic polymer solution having an alkoxysilyl group.

  By measuring the viscosity of the obtained (meth) acrylic polymer solution having an alkoxysilyl group at 25 ° C. with an Ubbelohde viscometer [manufactured by Mutual Riken Glass Co., Ltd., product number: U-0327-26], When the viscosity average molecular weight was determined, the viscosity average molecular weight was 3000.

Production Example 3
N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine [manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name] in a 500 mL Kolben equipped with a nitrogen gas inlet tube, a condenser and a stirrer : GLBT] 35.00 g, 3-mercaptopropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-803] 0.75 g and ethanol 143.02 g were added. After degassing by reducing the pressure inside the Kolben, nitrogen gas was introduced into the Kolben to return to normal pressure, and oxygen gas in the Kolben was eliminated as much as possible.

  Next, after the contents of Kolben are heated to 65 ° C. using an oil bath provided in Kolben, 0.89 g of azobisisobutyronitrile is added, and the temperature of the contents of Kolben is maintained at 70 ° C. The mixture was aged for 4 hours. Thereafter, 0.36 g of azobisisobutyronitrile was further added to the Kolben, and a polymer solution was obtained by aging for 4 hours while maintaining the reaction temperature at 70 ° C.

  The resulting polymer solution was cooled to 30 ° C. in a water bath and diluted with 178.78 g of ethanol to obtain a (meth) acrylic polymer solution having an alkoxysilyl group.

  By measuring the viscosity of the obtained (meth) acrylic polymer solution having an alkoxysilyl group at 25 ° C. with an Ubbelohde viscometer [manufactured by Mutual Riken Glass Co., Ltd., product number: U-0327-26], When the viscosity average molecular weight was determined, the viscosity average molecular weight was 5000.

Production Example 4
In a 500 mL Kolben equipped with a nitrogen gas inlet tube, a condenser and a stirrer, 30.00 g of methoxytriethylene glycol acrylate [manufactured by Osaka Organic Chemical Industry Co., Ltd., product number: V-MTG], 3-mercaptopropyltrimethoxysilane [Shin-Etsu Chemical Co., Ltd., trade name: KBM-803] 1.44 g and ethanol 125.68 g were added. After degassing by reducing the pressure inside the Kolben, nitrogen gas was introduced into the Kolben to return to normal pressure, and oxygen gas in the Kolben was eliminated as much as possible.

  Next, after the contents of Kolben were heated to 65 ° C. using an oil bath provided in Kolben, 1.57 g of azobisisobutyronitrile was added, and the temperature of the contents of Kolben was maintained at 70 ° C. The mixture was aged for 4 hours. Thereafter, 0.31 g of azobisisobutyronitrile was further added to the Kolben, and a polymer solution was obtained by aging for 4 hours while maintaining the reaction temperature at 70 ° C.

  The obtained polymer solution was cooled to 30 ° C. in a water bath and diluted with 157.10 g of ethanol to obtain a (meth) acrylic polymer solution having an alkoxysilyl group.

  By measuring the viscosity of the obtained (meth) acrylic polymer solution having an alkoxysilyl group at 25 ° C. with an Ubbelohde viscometer [manufactured by Mutual Riken Glass Co., Ltd., product number: U-0327-26], When the viscosity average molecular weight was determined, the viscosity average molecular weight was 5000.

Examples 1-4
The (meth) acrylic polymer solution having an alkoxysilyl group obtained in each production example is flow-coated on the low refractive index material layer of the substrate having the low refractive index material layer, and has an excess alkoxysilyl group. After removing the (meth) acrylic polymer solution by washing with ethanol, the substrate is placed in a warm air dryer and dried with warm air at a temperature of 120 ° C. for 30 minutes to have an alkoxysilyl group ( A low reflective material having a surface layer formed of a (meth) acrylic polymer was obtained. In addition, the base material which has a low refractive material layer was manufactured as follows.

[Manufacture of a substrate having a low refractive material layer]
By applying an ethanol solution containing 1% by mass of magnesium fluoride fine particles (average particle size: 10 nm) on a glass plate (length: 100 mm, width: 100 mm, thickness: 1 mm) and drying at 150 ° C., A substrate having a low refractive material layer was obtained. The refractive index of the surface of the obtained base material on which the low refractive material layer is formed is measured in an atmosphere of 23 ° C. using a refractometer [manufactured by Atago Co., Ltd., trade name: Digital Abbe refractometer DR-M2]. Measurement was performed at a measurement wavelength of 590 nm. As a result, the refractive index was 1.35.

  Next, as the physical properties of the low reflective material obtained above, the refractive index, antifogging property, contact angle with water, surface layer thickness and hot water resistance were examined based on the following methods. The results are shown in Table 1.

(Low reflectivity)
The refractive index in the surface layer of the low-reflective material was measured at a wavelength of 590 nm in an atmosphere at 23 ° C. using a refractometer (manufactured by Atago Co., Ltd., trade name: Digital Abbe refractometer DR-M2) as described above. And evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: The absolute value of the difference between the refractive index of the surface where the folded material layer is formed and the refractive index of the surface layer of the low-reflective material is less than 0.1 ×: The refractive index of the surface where the folded material layer is formed And the absolute value of the difference between the refractive index of the surface layer of the low reflective material is 0.1 or more

[Anti-fogging property]
The low reflective material was exposed to 90 ° C. water vapor for 5 minutes. By visually observing the antifogging property of this low reflective material, it was evaluated based on the following evaluation criteria.
(Evaluation criteria for anti-fogging properties)
○: No fogging occurs in low-reflective material ×: Cloudiness occurs in low-reflective material

[Contact angle with water]
A water droplet was dropped on the low-reflective material, and the contact angle with water was measured in a 25 ° C. atmosphere using a contact angle meter (manufactured by Elma Co., Ltd.), and evaluated based on the following evaluation criteria.
(Evaluation criteria for anti-fogging properties)
○: Contact angle with water is less than 10 degrees ×: Contact angle with water is 10 degrees or more

[Thickness of surface layer]
The thickness of the surface layer of the low-reflective material was measured using a stylus type step meter [manufactured by KLA-Tencor Corporation, product number: P-10].

[Heat resistant water]
A water droplet was dropped on the low-reflective material, and the contact angle with water was measured in the atmosphere at 25 ° C. using a contact angle meter (manufactured by Elma). Thereafter, this low-reflective material was immersed in hot water heated to 80 ° C. for 5 hours to conduct a heat resistant water test. Next, take out the low-reflective material from this hot water, wash it with water, dry the water adhering to the low-reflective material with an air gun, drop water droplets on the low-reflective material, and contact angle A contact angle with water was measured in a 25 ° C. atmosphere using a meter (manufactured by Elma Co., Ltd.), and hot water resistance was evaluated based on the following evaluation criteria.

(Evaluation criteria)
○: The absolute value of the difference in contact angle with water before and after the hot water test is less than 10 degrees X: The absolute value of the difference in contact angle with water before and after the hot water test is 10 degrees or more

Comparative Example 1
By applying an ethanol solution containing 1% by mass of magnesium fluoride fine particles (average particle size: 10 nm) on a glass plate (length: 100 mm, width: 100 mm, thickness: 1 mm) and drying at 150 ° C., A substrate having a low refractive material layer was obtained. Using the obtained base material having a low refractive material layer as a low reflective material, the physical properties of the low reflective material were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
A 1% sodium laurate aqueous solution is flow-coated on a glass plate, the glass plate is placed in a hot air dryer, and then heated at 120 ° C. for 30 minutes to dry the substrate treated with the surfactant. Obtained. Using the obtained substrate as a low reflective material, the physical properties of the low reflective material were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3
A 1% sodium myristate aqueous solution is flow-coated on a glass plate, the glass plate is placed in a hot air dryer, and then heated at 120 ° C. for 30 minutes to obtain a substrate treated with a surfactant. Obtained. Using the obtained substrate as a low reflective material, the physical properties of the low reflective material were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4
A 1% sodium palmitate aqueous solution is flow-coated on a glass plate, and the glass plate is placed in a warm air dryer and dried with warm air at a temperature of 120 ° C. for 30 minutes. Obtained. Using the obtained substrate as a low reflective material, the physical properties of the low reflective material were examined in the same manner as in Example 1. The results are shown in Table 1.

  From the results shown in Table 1, the low-reflective material obtained in each example is lower in the low-reflective material inherent in the low-reflective material than the low-reflective material obtained in each comparative example. It can be seen that the antifogging property is excellent with almost no decrease in the property. Furthermore, it can be seen that the low-reflective material obtained in each example is excellent in heat resistance since it is excellent in hot water resistance.

  The low-reflective material of the present invention is excellent in anti-fogging properties while hardly reducing the low-reflective property inherent to the low-reflective material, for example, rear mirrors such as automobiles and motorcycles, It is expected to be used in a wide range of applications such as display devices such as displays, optical filters, and solar cells.

Claims (5)

It has a base material, a low-refractive index material layer formed on the surface of the base material, and a surface layer formed on the low-refractive index material layer, and the surface layer has the formula (I):
(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrophilic group)
Having a repeating unit represented by formula (II) at least at one end:
(In the formula, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and among R ³ , R ⁴ and R ⁵ , At least one group of C 1-4 is an alkoxy group, and R ⁶ is an alkylene group of 1-12 carbon atoms)
A low-reflective material characterized by being formed of a (meth) acrylic polymer having an alkoxysilyl group represented by the formula: In formula (I), R ² is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms having at least one hydroxyl group, and a hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end, having 1 to 20 carbon atoms. A polyethylene glycol group, a polypropylene glycol group having 1 to 10 carbon atoms having a hydrogen atom or an alkyl group having 1 to 4 carbon atoms at one end, a formula (III):
(Wherein R ⁷ and R ⁸ are each independently an alkylene group having 1 to 4 carbon atoms, and R ⁹ and R ¹⁰ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)
Or a group represented by formula (IV):
Wherein R ¹¹ is an alkylene group having 1 to 4 carbon atoms, R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹⁴ is an organic group, and X ⁻ is an anion. Show)
The low-reflective material according to claim 1, which is a group represented by:   The low-reflective material according to claim 1 or 2, wherein the number of repeating units represented by formula (I) is 1-1000.   The low reflective material according to any one of claims 1 to 3, wherein the low refractive index material layer is formed of metal fluoride fine particles, silicon dioxide fine particles, or tin oxide fine particles. Formula (I):
(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrophilic group)
Having a repeating unit represented by formula (II) at least at one end:
(In the formula, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and among R ³ , R ⁴ and R ⁵ , At least one group of C 1-4 is an alkoxy group, and R ⁶ is an alkylene group of 1-12 carbon atoms)
A (meth) acrylic polymer for a low-reflective material, which has an alkoxysilyl group represented by the formula: