Anti-fog performance applying composition

Abstract

To provide a composition capable of satisfying both of anti-fog performance and water resistance.SOLUTION: An anti-fog performance applying composition includes a structural unit (a) derived from a (meth)acrylic acid (salt), and a structural unit (b) derived from a (meth)acrylic acid alkyl ester. The composition contains a polymer in which the content rate of the structural unit (a) is 5-70 mass% with respect to 100 mass% of all structural units.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an anti-fogging composition. More specifically, it relates to an anti-fogging composition useful for imparting anti-fogging properties to lenses and the like.

Background Art

[0002] When water vapor in the air is cooled and condensed, water droplets are generated on the surface of the base material (condensation). Due to the scattering of light by these minute water droplets, "fogging" occurs. Glasses used in building materials, vehicles, bathrooms, etc. where ensuring visibility is important, and optical materials such as lenses and glasses, etc. are required to prevent fogging, and anti-fogging treatment technologies have been developed.

[0003] Regarding compositions for imparting anti-fogging properties, for example, Patent Document 1 discloses an anti-fogging composition in which a crystalline three-layer structure of unrestricted layer-expanded type clay mineral, an acrylic resin having a glass transition temperature of 40°C to 75°C, and a nonionic surfactant are the main components and dispersed in a liquid dispersion composed of water or / and an alcohol-based solvent. Patent Document 2 discloses an anti-fogging coating material characterized by containing polyacrylic acids, polyvinyl alcohol, and acetylacetone. Patent Document 3 discloses a film-forming resin composition (A) containing a (meth)acrylic copolymer obtained by emulsion polymerization of a monomer mixture containing at least an alkyl (meth)acrylate and (meth)acrylic acid as monomers in the presence of a reactive nonionic emulsifier, an inorganic colloid sol (B), an aliphatic alcohol having 1 to 10 carbon atoms (C), and water (D), and an anti-fogging agent composition having a minimum film-forming temperature of -25°C or higher and 20°C or lower.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] As described above, conventionally, (meth)acrylic polymers have been used for anti-fogging treatment, but the coating film formed by the anti-fogging treatment is also required to have excellent water resistance. The compositions used in conventional anti-fogging treatments have not been sufficient in terms of achieving both anti-fogging properties and water resistance.

[0006] The present invention has been made in view of the above situation, and an object thereof is to provide a composition capable of achieving both anti-fogging properties and water resistance.

MEANS FOR SOLVING THE PROBLEMS

[0007] The present inventors conducted various studies on resins used for lenses and the like, and found that by using a polymer having a structural unit (a) derived from (meth)acrylic acid (salt) and a structural unit (b) derived from (meth)acrylic acid alkyl ester, and the content ratio of the structural unit (a) being 5 to 70% by mass based on 100% by mass of all structural units, excellent anti-fogging properties and water resistance (water whitening resistance and tack resistance) can be exhibited, and they conceived that the above problems can be solved perfectly and reached the present invention.

[0008] The present invention includes the following anti-fogging property-imparting compositions and the like. 〔1〕An anti-fogging property-imparting composition containing a polymer having a structural unit (a) derived from (meth)acrylic acid (salt) and a structural unit (b) derived from (meth)acrylic acid alkyl ester, and the content ratio of the structural unit (a) being 5 to 70% by mass based on 100% by mass of all structural units. 〔2〕The anti-fogging property-imparting composition according to the above 〔1〕, wherein the pH is 1.5 to 10.5. 〔3〕The anti-fogging property-imparting composition according to the above 〔1〕 or 〔2〕, wherein the content ratio of the structural unit (b) in the polymer is 30 to 95% by mass based on 100% by mass of all structural units. 〔4〕The polymerizable composition for imparting antifogging property according to any one of the above 〔1〕 to 〔3〕 is emulsion particles. 〔5〕The polymerizable composition for imparting antifogging property according to any one of the above 〔1〕 to 〔4〕 contains a surfactant. 〔6〕An antifogging property imparting method includes a step of forming a film of the polymerizable composition for imparting antifogging property according to any one of the above 〔1〕 to 〔5〕 on a substrate. 〔7〕The antifogging property imparting method according to the above 〔6〕 includes a step of adjusting the pH of the polymerizable composition for imparting antifogging property to 4.0 to 10.5, and the pH adjustment step is performed before the film forming step.

Advantages of the Invention

[0009] The polymerizable composition for imparting antifogging property of the present invention has the above-described configuration, and can achieve both antifogging property and water resistance, and thus can be suitably used for lenses and the like.

Embodiments for Carrying Out the Invention

[0010] Preferred embodiments of the present invention will be specifically described below. However, the present invention is not limited to the following description, and can be appropriately modified and applied without departing from the gist of the present invention. In addition, a form in which two or more of the individual preferred embodiments of the present invention described below are combined also falls within the scope of the preferred embodiments of the present invention.

[0011] <Polymerizable Composition for Imparting Antifogging Property> The polymerizable composition for imparting antifogging property of the present invention has a structural unit (a) derived from (meth)acrylic acid (salt) and a structural unit (b) derived from (meth)acrylic acid alkyl ester, and the content ratio of the structural unit (a) is 5 to 70% by mass based on 100% by mass of all structural units, and contains a polymer.

[0012] The ratio of the polymer in the polymerizable composition for imparting antifogging property is not particularly limited, but is preferably 0.01 to 30% by mass based on 100% by mass of the polymerizable composition for imparting antifogging property. More preferably, it is 0.05 to 25% by mass, still more preferably 0.07 to 20% by mass, and particularly preferably 0.1 to 15% by mass.

[0013] The above anti-fogging property-imparting composition may contain a surfactant. The proportion of the surfactant in the above anti-fogging property-imparting composition is not particularly limited, but is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, still more preferably 0.4 to 15% by mass, and particularly preferably 0.8 to 10% by mass with respect to 100% by mass of the anti-fogging property-imparting composition.

[0014] The above anti-fogging property-imparting composition may contain other components other than the above polymer and surfactant. The proportion of the other components in the above anti-fogging property-imparting composition is not particularly limited, but is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, still more preferably 0.4 to 15% by mass, and particularly preferably 0.8 to 10% by mass with respect to 100% by mass of the anti-fogging property-imparting composition.

[0015] The above anti-fogging property-imparting composition preferably has a pH of 1.5 to 10.5. Thereby, the anti-fogging property and water resistance can be further improved. More preferably, the pH is 3.0 to 10, still more preferably 4.0 to 9.0, even more preferably 5.0 to 8.5, and particularly preferably 5.5 to 8.0.

[0016] <Polymer> The polymer contained in the anti-fogging property-imparting composition of the present invention has a structural unit (a) derived from (meth)acrylic acid (salt) and a structural unit (b) derived from (meth)acrylic acid alkyl ester, and the content ratio of the structural unit (a) is 5 to 70% by mass with respect to 100% by mass of all structural units. By having 5% by mass or more of the hydrophilic structural unit (a) derived from (meth)acrylic acid (salt), a super-hydrophilic surface can be formed on the substrate, and excellent anti-fogging property can be exhibited. In addition, when the proportion of the structural unit (a) is 70% by mass or less, whitening due to water absorption of the coating film can be sufficiently suppressed.

[0017] In addition, due to the above structure of the polymer, it is also excellent in solubility in ethanol and film-forming property when forming a film on a substrate. The above polymer preferably has a solubility in ethanol of 1% by mass or more as measured by the following method. More preferably, the solubility in ethanol is 2 to 50% by mass. <Method for measuring solubility in ethanol> To 100 g of ethanol, a small amount of the polymer from which the solvent had been removed by drying was added little by little, and the solubility was calculated from the weight of the polymer added until undissolved residue remained without dissolution.

[0018] The content ratio of structural unit (a) in the above polymer is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, still more preferably 20 to 60% by mass, even more preferably 21 to 60% by mass, still even more preferably 25 to 60% by mass, still even more particularly preferably 30 to 60% by mass, and particularly preferably 35 to 60% by mass, based on 100% by mass of all structural units.

[0019] The content ratio of structural unit (b) in the above polymer is not particularly limited, but is preferably 30 to 95% by mass, more preferably 35 to 90% by mass, still more preferably 40 to 85% by mass, even more preferably 40 to 80% by mass, still even more preferably 40 to 75% by mass, still even more particularly preferably 40 to 70% by mass, and particularly preferably 40 to 65% by mass, based on 100% by mass of all structural units.

[0020] The above polymer may have a structural unit derived from a monomer other than (meth)acrylic acid (salt) and (meth)acrylic acid alkyl ester. The content ratio of the structural unit derived from other monomers is not particularly limited, but is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, still more preferably 0 to 1% by mass, particularly preferably 0 to 0.1% by mass, and most preferably 0% by mass, based on 100% by mass of all structural units.

[0021] The above polymer may be water-soluble or emulsion particles, but is preferably emulsion particles. Emulsion particles can be obtained by emulsion polymerization of monomer components. By emulsion polymerization, the amount of residual monomers can be reduced and the molecular weight can be increased, thereby further enhancing the strength of the coating film. The form in which the polymer of the present invention is emulsion particles is also one of the preferred embodiments of the present invention.

[0022] The degree of neutralization of the polymer of the present invention may be 10 mol% or more and 100 mol% or less, more preferably 15 mol% or more and 100 mol% or less, still more preferably 20 mol% or more and 100 mol% or less, based on 100 mol% of the carboxyl groups of the polymer. When the degree of neutralization of the polymer is within the above range, good antifogging properties are expected, and solubility in alcohol is also preferably improved. When the polymer of the present invention is used as an antifogging composition, it is also a preferred form of use to dissolve it in alcohol before use. The boiling point of the alcohol used is preferably 100 °C or lower, more preferably 95 °C or lower, still more preferably 90 °C or lower. Examples of the alcohol used include methanol, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, ethylene glycol, and glycerin, with ethanol and isopropyl alcohol being preferred.

[0023] The structural unit derived from the above (meth)acrylic acid (salt) and the structural unit derived from the (meth)acrylic acid alkyl ester each mean a structure in which the unsaturated double bond part (C=C) of the (meth)acrylic acid (salt) or the (meth)acrylic acid alkyl ester becomes a single bond (-C-C-). This structure may be formed not only in a polymer obtained by polymerizing (meth)acrylic acid (salt) or (meth)acrylic acid alkyl ester, but also by post-modification of a polymer obtained by polymerizing other monomers to form a structural unit derived from (meth)acrylic acid (salt) or a structural unit derived from alkyl (meth)acrylate.

[0024] The above (meth)acrylic acid(salt) means acrylic acid, acrylate, methacrylic acid, and methacrylate. Among the (meth)acrylic acid(salt), methacrylic acid and methacrylate are preferable from the viewpoint of stability during polymerization. More preferably, it is a methacrylate.

[0025] The above (meth)acrylic acid alkyl ester may be an ester of (meth)acrylic acid and an alkyl alcohol, but may be obtained by other methods as long as it has the same structure. The carbon number of the alkyl group of the above (meth)acrylic acid alkyl ester is not particularly limited, but is preferably 1 to 10. The (meth)acrylic acid alkyl ester having an alkyl group with 1 to 10 carbon atoms has a suitable glass transition temperature. By using such a (meth)acrylic acid alkyl ester, stickiness of the coating film can be sufficiently suppressed and water resistance can be further improved. In addition, since the (meth)acrylic acid alkyl ester having an alkyl group with 10 or less carbon atoms is excellent in polymerizability, a polymer can be efficiently produced. More preferably, the carbon number of the alkyl group is 2 to 8, still more preferably 2 to 6, even more preferably 2 to 5, and particularly preferably 2 to 4.

[0026] Specific examples of the above (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, i-propyl (meth)acrylate, sec-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 1-methylbutyl (meth)acrylate, 1-ethylpropyl (meth)acrylate, 2-methylbutyl (meth)acrylate, i-amyl (meth)acrylate, neopentyl (meth)acrylate, 1,2-dimethylpropyl (meth)acrylate, 1,1-dimethylpropyl (meth)acrylate, t-amyl (meth)acrylate, 1,3-dimethylbutyl (meth)acrylate, 3,3-dimethylbutyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, 2-ethyl-2-methylpropyl (meth)acrylate, 1-methylheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 1,5-dimethylhexyl (meth)acrylate, t-octyl (meth)acrylate and the like. Among them, ethyl (meth)acrylate, n-propyl (meth)acrylate and n-butyl (meth)acrylate are preferable, and ethyl (meth)acrylate is more preferable.

[0027] The above polymer may have structural units derived from other monomers other than (meth)acrylic acid (salt) and (meth)acrylic acid alkyl ester. The other monomers are not particularly limited, and examples thereof include (meth)acrylic acid esters having a hydroxyl group, (meth)acrylic acid esters having an alkoxy group, monomers having an amide group, aromatic vinyls and the like.

[0028] Examples of the (meth)acrylic acid ester having a hydroxyl group include hydroxyl group-containing (meth)acrylic acid esters having 1 to 18 carbon atoms in the ester group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0029] Examples of the (meth)acrylic acid ester having an alkoxy group include methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, and trimethylolpropane tripropoxy (meth)acrylate.

[0030] Examples of the monomer having an amide group include (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-n-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, methylenebis(meth)acrylamide, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl acrylamide, and diacetone acrylamide.

[0031] Examples of the above aromatic vinyls include alkylstyrenes having 1 to 4 carbon atoms in the alkyl group such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, tert-methylstyrene, o-tert-butylstyrene, m-tert-butylstyrene, p-tert-butylstyrene; alkoxystyrenes having 1 to 4 carbon atoms in the alkoxy group such as o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, o-tert-butoxystyrene, m-tert-butoxystyrene, p-tert-butoxystyrene; halogen atom-containing styrenes such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene; acetoxystyrenes such as o-acetoxystyrene, m-acetoxystyrene, p-acetoxystyrene; and vinyltoluene.

[0032] The above polymer may have a structure derived from a crosslinking agent. The proportion of the structure derived from the crosslinking agent in the above polymer is not particularly limited, but is 0.001 to 10% by mass, more preferably 0.01 to 1% by mass, and still more preferably 0.03 to 0.3% by mass based on 100% by mass of all structural units. Note that all structural units are structural units derived from (meth)acrylic acid (salt), (meth)acrylic acid alkyl ester, and other monomers, and the structure derived from the crosslinkable monomer is not included in all structural units.

[0033] The crosslinking agent is not particularly limited. For example, compounds having two or more ethylenically unsaturated groups in one molecule such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, N,N'-methylenebis(meth)acrylamide, triallyl isocyanurate, trimethylolpropane di(meth)allyl ether, triallylamine, tetraallyloxyethane, glycerol propoxytriacrylate are preferred, and compounds having two ethylenically unsaturated groups in one molecule such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate are more preferred.

[0034] The method for producing the above polymer is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method, etc. can be used. From the viewpoint of reducing residual monomers, an emulsion polymerization method or a suspension polymerization method is preferred. From the viewpoint of increasing the strength of the coating film by increasing the molecular weight, the emulsion polymerization method is more preferred. Among them, from the viewpoint of safety, it is more preferable to use an aqueous medium such as water as the solvent. The method for producing the above polymer preferably includes a step of polymerizing a monomer component. The method for emulsion polymerizing the monomer used in the polymer of the present disclosure is not particularly limited, but in the presence of a surfactant such as a polyoxyalkylene alkyl ether-based surfactant, it is preferable to emulsion polymerize a monomer component containing (meth)acrylic acid (salt) and an alkyl (meth)acrylate. More preferably, the surfactant is a polyoxyalkylene alkyl ether-based nonionic surfactant or a polyoxyalkylene alkyl ether-based anionic surfactant.

[0035] When emulsion-polymerizing the above monomer component, methods such as dissolving a surfactant in an aqueous medium and dropping the monomer component and a polymerization initiator therein under stirring, and dropping a pre-emulsion previously emulsified using a surfactant and an aqueous medium into the aqueous medium can be mentioned, but it is not limited to such methods only. Among them, from the viewpoint of production efficiency, a method of dissolving a surfactant in an aqueous medium and dropping the monomer component and a polymerization initiator therein under stirring is preferable. More preferably, it is a method of dropping the monomer component and a polymerization initiator into a reaction kettle into which the total amount of the surfactant has been charged. The amount of the aqueous medium may be appropriately set in consideration of the non-volatile content contained in the resulting emulsion. The aqueous medium may be charged into the reaction vessel in advance, or may be used as a pre-emulsion. Further, the aqueous medium may be used when necessary for emulsion-polymerizing the monomer component to produce an emulsion.

[0036] When emulsion-polymerizing the monomer component, emulsion polymerization may be carried out after mixing the monomer component, the surfactant and the medium, or the monomer component, the surfactant and the medium may be emulsified by stirring to prepare a pre-emulsion and then emulsion polymerization may be carried out, or at least one of the monomer component, the surfactant and the medium and the pre-emulsion of the remainder may be mixed to carry out emulsion polymerization. The monomer component, the surfactant and the medium may be added all at once, added in portions, or continuously dropped. From the viewpoint of suppressing the generation of aggregates, it is preferable to emulsify the monomer component, the surfactant and the medium by stirring to prepare a pre-emulsion and then carry out emulsion polymerization.

[0037] Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, and 4,4-azobis(4-cyanovaleric acid); persulfates such as ammonium persulfate and potassium persulfate; peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide; redox polymerization initiators composed of combinations such as hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalit, potassium persulfate and metal salts, and ammonium persulfate and sodium bisulfite; etc., but are not particularly limited. The above polymerization initiators may be used alone or in combination of two or more.

[0038] From the viewpoint of increasing the polymerization rate and reducing the residual amount of unreacted monomer components, the amount of the polymerization initiator per 100 parts by mass of the monomer component is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more. Also, it is preferably 1 part by mass or less, more preferably 0.5 part by mass or less.

[0039] The addition method of the polymerization initiator is not particularly limited. Examples of the addition method include batch charging, split charging, continuous dropping, etc. Also, from the viewpoint of accelerating the end time of the polymerization reaction, a part of the polymerization initiator may be added before or after the completion of the addition of the monomer component into the reaction system.

[0040] As the method for producing the above polymer, in order to promote the decomposition of the polymerization initiator, a decomposition agent for the polymerization initiator such as a reducing agent such as sodium bisulfite and a transition metal salt such as ferrous sulfate may be added in an appropriate amount to the reaction system.

[0041] In addition, a chain transfer agent can be used to adjust the weight average molecular weight of the emulsion particles. Examples of the chain transfer agent include 2-ethylhexyl thioglycolate, tert-dodecyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, α-methylstyrene dimer, etc., but are not limited to these examples. These chain transfer agents may be used alone or in combination of two or more kinds. The amount of the chain transfer agent per 100 parts by mass of the monomer component may be 0.01 to 10 parts by mass from the viewpoint of appropriately adjusting the weight average molecular weight of the emulsion particles.

[0042] In the method for producing the polymer, additives such as a pH buffer, a chelating agent, a film-forming aid, etc. may be added to the reaction system as necessary. The amount of the additive varies depending on the type and cannot be determined in general, but the amount of the additive per 100 parts by mass of the monomer component may be 0.01 to 5 parts by mass, or 0.1 to 3 parts by mass.

[0043] In the method for producing the above polymer, the atmosphere in which the monomer components are emulsion-polymerized is not particularly limited, but from the viewpoint of increasing the efficiency of the polymerization initiator, an inert gas such as nitrogen gas is preferable.

[0044] The polymerization temperature when emulsion-polymerizing the monomer components is not particularly limited, but is usually preferably 50 to 100° C., more preferably 60 to 95° C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

[0045] The polymerization time for emulsion-polymerizing the monomer components is not particularly limited and may be appropriately set depending on the progress of the polymerization reaction, but is usually about 2 to 9 hours.

[0046] When emulsion-polymerizing the monomer component, part or all of the carboxylic acid groups of the resulting polymer component may be neutralized with a neutralizing agent. However, from the viewpoint of water resistance, the neutralizing agent is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, and particularly preferably not using a neutralizing agent, based on 100 parts by mass of (meth)acrylic acid.

[0047] Examples of the neutralizing agent include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide; carbonates of alkali metals or alkaline earth metals such as sodium hydrogen carbonate and calcium carbonate; and alkaline substances such as organic amines such as ammonia, monomethylamine, and dimethylaminoethanol. However, the invention is not limited only to such examples.

[0048] <Surfactant> The anti-fogging property-imparting composition of the present invention may contain a surfactant. The surfactant is not particularly limited, and examples thereof include polyoxyalkylene alkyl ether-based surfactants. Examples of the polyoxyalkylene alkyl ether-based surfactant include nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyldodecyl ether, and polyoxyethylene behenyl ether; and anionic surfactants such as polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, and salts thereof. Examples of the polyoxyalkylene group include those obtained by adding 1 to 30 moles of an alkylene oxide having 2 to 4 carbon atoms. Ethylene oxide is preferable as the alkylene oxide, and it is also preferable that the added mole number of ethylene oxide is from 1 mole to 30 moles. Examples of the salt types include metals such as sodium and potassium, and amines such as mono-, di-, and triethanolamine, and 2-amino-2-methyl-1-propanol. Particularly, polyoxyethylene lauryl ether sulfate is preferable.

[0049] The above-described anti-fog property-imparting composition may contain other components other than the above polymer and surfactant. The other components are not particularly limited, and examples thereof include defoamers, plasticizers, film-forming aids, thickeners, pigments, pigment dispersants, weather resistance improvers, heat stabilizers, and the like.

[0050] The present invention is also an anti-fog property-imparting method including a step of forming a film of the anti-fog property-imparting composition of the present invention on a substrate. The above anti-fog property-imparting method is not particularly limited as long as it forms a film of the anti-fog property-imparting composition on a substrate, but further includes a step of adjusting the pH of the anti-fog property-imparting composition to 4.0 to 10.5, and it is preferable to perform the pH adjustment step before the above film-forming step. In the above pH adjustment step, it is preferably adjusted to a pH of 4.5 to 10.0, more preferably 5.0 to 9.0, still more preferably 5.5 to 8.5, and particularly preferably 5.5 to 8.0. The above pH can be adjusted by neutralizing the carboxyl groups of the polymer in the anti-fog property-imparting composition. The base used for neutralization is not particularly limited, and the above neutralizing agent can be used. Preferably, it is an alkali metal such as sodium hydroxide. It is preferable to use such a neutralizing agent to make the degree of neutralization of the polymer within the above range.

[0051] In the above film-forming step, it is preferable to apply the anti-fog property-imparting composition to a substrate and form a coating film by volatilizing the solvent or dispersion medium. The volatilization of the solvent or dispersion medium can be carried out by forced drying or natural drying such as hot air drying method, infrared radiation method, etc.

[0052] The heating temperature during forced drying may be determined according to the applied anti-fog property-imparting composition, but is preferably 50 to 250 °C, more preferably in the range of 70 to 200 °C.

[0053] The method for applying the above anti-fog property-imparting composition to a substrate is not particularly limited, and any method known per se such as roll coating method, dip coating method, brush coating method, spray coating method, bar coating method, knife coating method, etc. may be used.

[0054] In the above anti-fog property imparting method, after applying the anti-fog property imparting composition to the surface of the substrate and drying it, the adhesion amount of the solid matter is 0.01 to 10 g / m 2 is preferable, and 0.1 to 5 g / m 2 is more preferable. When the adhesiveness between the substrate surface and the coating film derived from the anti-fog property imparting composition is not sufficient, before applying the anti-fog property imparting composition, the substrate surface may be modified by performing plasma treatment or corona discharge treatment on the substrate surface.

[0055] The substrate to which the anti-fog property imparting composition of the present invention is applied is not particularly limited, but glass used in building materials, vehicles, bathrooms, etc. where ensuring visibility is important, and optical materials that require transparency are preferable. More preferably, the substrate is a lens, film, filter, sheet, etc., still more preferably a lens, and particularly preferably an eyeglass lens.

Examples

[0056] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited only to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass". The compositions obtained in the examples and comparative examples were analyzed and evaluated by the following methods.

[0057] <Measurement of non-volatile content> Weighed about 1 g of the reaction solution in an aluminum dish, dried it in a hot air dryer at 120 °C for 20 minutes, and determined it from the weights before and after drying by the following formula. Non-volatile content (%) = (mass after drying) / (mass before drying) × 100

[0058] <pH measurement> The value at 25 °C was measured with a pH meter (manufactured by Horiba, Ltd., "F-72").

[0059] <Evaluation of anti-fog property> Preparation of a transparent acrylic plate with a coating film: Using the composition synthesized in the production example, a test solution was prepared to have the composition shown in Table 1. This test solution was applied to a transparent acrylic resin plate [manufactured by Nippon Test Panel Co., Ltd., vertical: 150 mm, horizontal: 70 mm, thickness: 2 mm] with an aqueous resin composition for topcoat paint using a 10-mil applicator, and dried in air at 25°C for 24 hours to obtain a test plate.

[0060] Evaluation of antifogging property of the film: A transparent acrylic plate with a coating film is placed at a height of 2 cm from the water surface of a constant temperature water bath maintained at a water temperature of 50°C so that the coating film faces downward. The transparency of the coating film 10 minutes after placement was visually confirmed, and the "antifogging property evaluation" was performed according to the criteria shown below. ◎: It does not fog at all during the test. 〇: The coating film becomes slightly foggy, but the state of the liquid surface can be confirmed through the test plate. ×: The coating film becomes thickly foggy, and the state of the liquid surface cannot be confirmed through the test plate.

[0061] Evaluation of water resistance of the film: A transparent acrylic plate with a coating film is placed at a height of 2 cm from the water surface of a constant temperature water bath maintained at a water temperature of 50°C so that the coating film faces downward. The coating film 10 minutes after placement was touched with a finger, and the "water resistance evaluation" was performed according to the criteria shown below. ◎: No stickiness is felt. 〇: A weak stickiness is felt, but no stickiness remains on the finger. ×: A strong stickiness is felt, and stickiness remains on the finger.

[0062] [Production Example 1] Into a flask equipped with a dropping device, a stirring device, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 2.9 parts of Emal 20C (sodium polyoxyethylene (3) lauryl ether sulfate, manufactured by Kao Corporation, active ingredient 25%), 0.5 part of Emulgen 106 (polyoxyethylene (5) lauryl ether, manufactured by Kao Corporation, active ingredient 100%), and 161.6 parts of ion-exchanged water were charged. Next, while stirring and heating up to 80 °C, the inside of the flask was purged with nitrogen gas. On the other hand, 24 parts of methacrylic acid and 36 parts of ethyl acrylate were mixed to prepare a dropping monomer solution. Next, 3 parts of the dropping monomer solution were charged all at once into the aqueous solution in the flask, and the mixture was stirred at 80 °C for 5 minutes. Subsequently, 1 part of a 1.5% aqueous ammonium persulfate solution as a polymerization initiator was added to the flask, and initial polymerization was carried out by stirring at 80 °C for 20 minutes. Thereafter, while maintaining the reaction temperature at 80 °C, the remaining 57 parts of the dropping monomer solution were dropped from the dropping device over 2 hours, and at the same time, 9 parts of a 1.5% aqueous ammonium persulfate solution were dropped over 2 hours. After completion of the dropping, the dropping device was immediately rinsed by flowing 5 g of ion-exchanged water into the flask. After completion of the dropping, the reaction was further continued for 2 hours, and then the reaction solution was cooled to terminate the polymerization reaction, obtaining Composition 1. The nonvolatile content of the obtained reaction solution (Composition 1) was 25.7%, and ion-exchanged water was added to adjust the nonvolatile content to 25%. The pH was 2.5.

[0063] [Production Example 2] A flask equipped with a dropping device, a stirring device, a nitrogen gas inlet tube, a thermometer, and a reflux condenser was charged with 2.9 parts of Emal 20C (sodium polyoxyethylene (3) lauryl ether sulfate, manufactured by Kao Corporation, active ingredient 25%), 0.5 part of Emulgen 106 (polyoxyethylene (5) lauryl ether, manufactured by Kao Corporation, active ingredient 100%), and 161.6 parts of ion-exchanged water. Next, while raising the temperature with stirring up to 80 °C, the inside of the flask was purged with nitrogen gas. On the other hand, 36 parts of methacrylic acid and 24 parts of ethyl acrylate were mixed to prepare a dropping monomer solution. Next, 3 parts of the dropping monomer solution were charged all at once into the aqueous solution in the flask, and the mixture was stirred at 80 °C for 5 minutes. Subsequently, 1 part of a 1.5% aqueous ammonium persulfate solution as a polymerization initiator was added to the flask, and initial polymerization was carried out by stirring at 80 °C for 20 minutes. Thereafter, while maintaining the reaction temperature at 80 °C, the remaining 57 parts of the dropping monomer solution were dropped from the dropping device over 2 hours, and at the same time, 9 parts of a 1.5% aqueous ammonium persulfate solution were dropped over 2 hours. After completion of the dropping, the dropping device was immediately rinsed by flowing 5 g of ion-exchanged water into the flask. After completion of the dropping, the reaction was continued for an additional 2 hours, and then the reaction solution was cooled to terminate the polymerization reaction to obtain Composition 2. The non-volatile content of the obtained reaction solution (Composition 2) was 25.5%, and ion-exchanged water was added to adjust the non-volatile content to 25%. The pH was 2.3.

[0064] [Production Example 3] Into a flask equipped with a dropping device, a stirring device, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 2.9 parts of Emal 20C (sodium polyoxyethylene (3) lauryl ether sulfate, manufactured by Kao Corporation, active ingredient 25%), 0.5 part of Emulgen 106 (polyoxyethylene (5) lauryl ether, manufactured by Kao Corporation, active ingredient 100%), and 161.6 parts of ion-exchanged water were charged. Next, while stirring and heating up to 80 °C, the inside of the flask was replaced with nitrogen gas. On the other hand, 6 parts of methacrylic acid and 54 parts of ethyl acrylate were mixed to prepare a dropping monomer solution. Next, 3 parts of the dropping monomer solution were charged all at once into the aqueous solution in the flask, and the mixture was stirred at 80 °C for 5 minutes. Subsequently, 1 part of a 1.5% aqueous ammonium persulfate solution as a polymerization initiator was added to the flask, and initial polymerization was carried out by stirring at 80 °C for 20 minutes. Thereafter, while maintaining the reaction temperature at 80 °C, the remaining 57 parts of the dropping monomer solution were dropped from the dropping device over 2 hours, and at the same time, 9 parts of a 1.5% aqueous ammonium persulfate solution were dropped over 2 hours. After completion of the dropping, the dropping device was immediately rinsed by flowing 5 g of ion-exchanged water into the flask. After completion of the dropping, the reaction was continued for another 2 hours, and then the reaction solution was cooled to terminate the polymerization reaction to obtain Composition 3. The non-volatile content of the obtained reaction solution (Composition 3) was 25.8%, and ion-exchanged water was added to adjust the non-volatile content to 25%. The pH was 2.7.

[0065] The test solutions were adjusted so that the compositions synthesized in Production Examples 1 and 2 and polyvinylpyrrolidone (manufactured by Nippon Shokubai Co., Ltd., PVP-K90) had the blending compositions shown in Table 1, and test plates were prepared using these, and the anti-fogging property and water resistance were evaluated. The results are shown in Table 1.

[0066]

Table 1

Claims

1. An anti-fogging property-imparting composition comprising a polymer having a structural unit (a) derived from (meth)acrylic acid (salt) and a structural unit (b) derived from an alkyl (meth)acrylate, wherein the content ratio of the structural unit (a) is 5 to 70% by mass based on 100% by mass of all the structural units.

2. The anti-fogging property-imparting composition according to claim 1, wherein the pH is 1.5 to 10.

5.

3. The anti-fogging property-imparting composition according to claim 1 or 2, wherein the content ratio of the structural unit (b) in the polymer is 30 to 95% by mass based on 100% by mass of all the structural units.

4. The anti-fogging property-imparting composition according to claim 1 or 2, wherein the polymer is emulsion particles.

5. The anti-fogging property-imparting composition according to claim 1 or 2, wherein the anti-fogging property-imparting composition contains a surfactant.

6. An anti-fogging property-imparting method comprising a step of forming a film of the anti-fogging property-imparting composition according to claim 1 or 2 on a substrate.

7. The anti-fogging property-imparting method according to claim 6, wherein the anti-fogging property-imparting method includes a step of adjusting the pH of the anti-fogging property-imparting composition to 4.0 to 10.5, and the pH adjustment step is performed before the film-forming step.

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