JP6912751B2 - Urethane paint composition, cured coating, and resin members - Google Patents

Description

The present invention relates to urethane coating compositions, cured coatings, and resin members.

Conventionally, it has been known that when the surface of a base material such as a synthetic resin molded product or glass falls below the dew point temperature, the moisture in the atmosphere becomes fine water droplets and adheres to the surface of the base material. As a result, light is scattered by the attached water droplets and cloudiness occurs. Therefore, for example, when the above-mentioned base material is used for eyeglasses or the like, the visibility is obstructed.

As a method for preventing the occurrence of fogging (anti-fog), a solution of a mixture of a hydrophilic resin and a surfactant is applied to the surface of the base material to form a coating film (dry coating film or cured coating film). The method is known.

In this method, the surfactant contained in the coating film lowers the contact angle of the attached water droplets and does not cause light scattering, thereby exhibiting an antifogging effect. In addition, in this method, the contact angle of water droplets is rapidly lowered by the surfactant, so that the antifogging effect can be quickly exhibited.

However, when considering the actual use of the above coating film (for example, when it is used for a long period of time or when the surface of the coating film is wiped with water), the surfactant in the coating film easily flows out to prevent fogging. The sex is reduced. On the other hand, by adding a large amount of surfactant, the antifogging durability can be improved to some extent, but it cannot be significantly improved, the coating film is easily damaged, and the appearance of the coating film is also deteriorated. There is a problem of doing it.

In order to prevent such outflow of the surfactant, a method of using a surfactant which is difficult to dissolve in water (Patent Document 1) and a method of using a reactive surfactant (Patent Documents 2 and 3) have been reported. There is.

JP-A-2015-86370 Japanese Unexamined Patent Publication No. 2005-29723 Japanese Unexamined Patent Publication No. 2004-244612

Since the cured coating film disclosed in Patent Document 1 has a low water solubility of the surfactant, the surfactant does not flow out into the water even when immersed in water, so that antifogging durability can be expected. Further, since it is presumed that a large amount of surfactant is present on the outermost surface of the coating film, a uniform water film can be formed. However, when the antifogging coating film is wiped with water, there is a concern that the surfactant existing on the outermost surface of the coating film is removed and good antifogging property cannot be maintained.

On the other hand, in the cured coating film disclosed in Patent Documents 2 and 3, a reactive surfactant having a functional group that reacts with the isocyanate component is introduced into a two-component curable resin containing an isocyanate component and a polyol component. Since the surfactant can be co-bonded to the resin component in the coating film, even when the coating film is immersed in water, the outflow of the surfactant is small and anti-fog durability can be expected. However, since the above-mentioned reactive surfactant is monofunctional, it has been found that there is a problem that the crosslink density in the coating film is lowered and the scratch resistance is insufficient. On the other hand, it was found that when the amount of the above-mentioned reactive surfactant used was set to the minimum amount capable of maintaining scratch resistance, anti-fog property and anti-fog persistence were not exhibited.

As described above, in the actual use of the coating film (dry coating film or cured coating film) in the conventional technique, there are still problems such as deterioration of antifogging property or deterioration of appearance due to scratches. Therefore, there is a demand for an antifogging coating film that can exhibit good antifogging properties even after repeated wiping of the coating film surface with water while maintaining the film strength capable of exhibiting good scratch resistance.

An object of the present invention is to provide a urethane coating composition capable of forming a cured coating film having excellent antifogging durability while having good scratch resistance, and a resin member having the cured coating film. do.

The present invention is a urethane coating composition containing a polyisocyanate (a), a polyether polyol (b), and a surfactant (c), wherein the polyisocyanate (a) is composed of a diisocyanate and a derivative thereof. At least one polyisocyanate compound selected, the polyether polyol (b) has a number average molecular weight of 300 or more and 1800 or less, and the surfactant (c) has an ionic interface having a hydroxyl group in the molecule. An anionic surfactant and / or an amphoteric surfactant having no reactive group between the active agent and the isocyanate group, and the component (a) in the total weight of the components (a) to (c). Is 30% by weight or more and 60% by weight or less, the component (b) is 35% by weight or more and 65% by weight or less, and the component (c) is 1% by weight or more and 10% by weight or less. Regarding urethane coating composition.

The present invention also relates to a cured coating film, which is formed from the urethane coating composition.

Furthermore, the present invention relates to a resin member having the cured coating film.

The urethane coating composition of the present invention is a urethane coating composition containing a specific polyisocyanate (a), a polyether polyol (b), and a surfactant (c) in a specific amount. The cured coating film formed from these components has good scratch resistance and excellent antifogging durability, so that it can withstand repeated wiping of the coating film and is suitable for actual use.

Further, in the present invention, as the surfactant (c), an ionic surfactant having a hydroxyl group in the molecule and an anionic surfactant and / or an amphoteric surfactant having no reactive group with an isocyanate group Use an activator in combination. An ionic surfactant having a hydroxyl group in the molecule and an anionic surfactant and / or an amphoteric surfactant having no reactive group with an isocyanate group can each improve the initial antifogging property. .. Furthermore, the coexistence of both surfactant components, which are easily released from the cured coating film when used alone, forms an aggregate and makes it difficult to release, thus providing anti-fog durability. It is presumed that it can be improved.

The urethane coating composition of the present invention contains a polyisocyanate (a), a polyether polyol (b), and a surfactant (c).

<Polyisocyanate (a)>
The polyisocyanate (a) of the present invention is at least one polyisocyanate compound selected from the group consisting of diisocyanates and derivatives thereof. Examples of the diisocyanate include aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate; and alicyclic diisocyanates such as 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; Examples thereof include aromatic diisocyanates such as xylylene diisocyanate, tolylen-2,6-diisocyanate, and diphenylmethane diisocyanate. The derivative of the diisocyanate is, for example, synthesized from the aliphatic diisocyanate, the alicyclic diisocyanate, and / or the aromatic diisocyanate as a starting material, and is a bullet form, an adduct form with trimethylolpropane, or an isocyanurate form. , Aliphatic diisocyanate derivatives such as allophanate, alicyclic diisocyanate derivatives, aromatic diisocyanate derivatives and the like. The polyisocyanate (a) may be used alone or in combination of two or more.

The polyisocyanate (a) is preferably an aliphatic diisocyanate derivative, an alicyclic diisocyanate derivative, or an aromatic diisocyanate derivative from the viewpoint of increasing the cross-linking density of the cured coating film and improving the scratch resistance. A derivative of diisocyanate is more preferable, and a derivative of 1,3-bis (isocyanatomethyl) cyclohexane and a derivative of isophorone diisocyanate are further preferable. The derivative is preferably an adduct with trimethylolpropane. In particular, the polyisocyanate (a) contains 1,3-bis (isocyanatomethyl) cyclohexane, trimethylolpropane adduct, and isophorone diisocyanate from the viewpoint of improving the scratch resistance and antifogging property of the cured coating film. It is preferable to use trimethylolpropane in combination with an adduct body.

As commercially available products, the polyisocyanate (a) is, for example, a bullet form of hexamethylene diisocyanate (manufactured by Asahi Kasei Chemicals Co., Ltd., trade name: Duranate 24A-100) and an isocyanurate form of hexamethylene diisocyanate (Asahi Kasei Chemicals Co., Ltd.). Company, product name: Duranate TPA-100), hexamethylene diisocyanate allophanate (Suika Bayer Urethane Co., Ltd., product name: Death Module XP2679), isophorone diisocyanate trimethylolpropan adduct (Sumika Bayer Urethane Co., Ltd.) , Product name: Death module Z4470BA), 1,3-bis (isocyanatomethyl) cyclohexane trimethylolpropane adduct (manufactured by Mitsui Chemicals, Inc., product name: Takenate D-120N), 1,3-bis (isocyanate) Isophorone diisocyanate isocyanurate (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takenate D-127N), isophorone diisocyanate trimethylol propanadduct (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takenate D-140N), etc. Be done.

<Polyester polyol (b)>
The polyether polyol (b) of the present invention has a number average molecular weight of 300 or more and 1800 or less. The number average molecular weight can be calculated from the hydroxyl value of the polyether polyol (b).

As the polyether polyol (b), for example, at least one selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran and the like is added to a polyfunctional alcohol such as glycerin and pentaerythritol. Examples of the polymer obtained by. As the alkylene oxide, those containing ethylene oxide are preferable, and those to which only ethylene oxide is added are more preferable. The polyether polyol (b) may be used alone or in combination of two or more.

Examples of the polyether polyol (b) include polyethylene glycol, a copolymer polyol of polypropylene glycol polyethylene glycol / polypropylene glycol, polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene polyoxypropylene glyceryl ether, and poly. Examples thereof include oxyethylene polyoxypropylene trimethylolpropane, polyoxypropylene diglyceryl ether, pentaerythritol polyoxyethylene ether, and polyoxyethylene polyoxypropylene pentaerythritol ether. In particular, the polyether polyol (b) is a polyoxyethylene glyceryl ether, a polyoxypropylene glyceryl ether, a polyoxyethylene polyoxypropylene glyceryl ether, or a poly from the viewpoint of improving the scratch resistance and antifogging property of the cured coating film. It is preferable to use oxypropylene diglyceryl ether.

The number average molecular weight of the polyether polyol (b) is preferably 400 or more, more preferably 500 or more, and more preferably 700 or more, from the viewpoint of enhancing compatibility with the polyisocyanate (a). Is even more preferable. The number average molecular weight of the polyether polyol (b) is preferably 1500 or less, more preferably 1200 or less, and 1000 or less, from the viewpoint of improving the scratch resistance of the cured coating film. Is even more preferable.

The number of hydroxyl groups per molecule of the polyether polyol (b) is preferably 2 or more, and more preferably 3 or more, from the viewpoint of improving the scratch resistance of the cured coating film. The number of hydroxyl groups per molecule of the polyether polyol (b) is preferably 6 or less, and more preferably 4 or less, from the viewpoint of enhancing compatibility with the polyisocyanate (a).

<Surfactant (c)>
The surfactant (c) of the present invention is an ionic surfactant having a hydroxyl group in the molecule and an anionic surfactant and / or an amphoteric surfactant having no reactive group with an isocyanate group. ..

The ionic surfactant having a hydroxyl group in the molecule is a cationic, anionic, or amphoteric surfactant. The ionic surfactant having a hydroxyl group in the molecule may be used alone or in combination of two or more.

Examples of the ionic surfactant having a hydroxyl group in the molecule include a dialkanolamine salt, a trialkanolamine salt, a polyoxyalkylene alkylamine ether salt, and a fatty acid trialkanolamine ester salt. Polyoxyalkylenedialkanolamine ether salt, polyoxyalkylenetrialkanolamine ether salt, di (polyoxyalkylene) alkylbenzylalkylammonium salt, alkylcarbamoylmethyldi (polyoxyalkylene) ammonium salt, polyoxyalkylenealkylammonium salt, poly Examples thereof include oxyalkylene dialkylammonium salts.

Further, in the ionic surfactant having a hydroxyl group in the molecule, as a cationic surfactant, for example, the general formula (1):
R ¹ −NH − (CH ₂ ) _n −N ⁺ R ² R ³ R ⁴ X ⁻
(In the general formula (1), R ¹ represents a saturated or unsaturated acyl group having a linear or branched chain having 8 to 24 carbon atoms, and has one or more hydroxyl groups, and n is 1 to 10. ^represents, R 2 to R ⁴ are independently hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, X is include compounds represented by an anion.) Be done.

Examples of the compound represented by the general formula (1) include ricinol amide propyl dimethylamine, ricinol amide propyl ethyldimonium etosulfate, ricinol amide propyltrimonium chloride, ricinol amide propyl trimonium metosulfate, and cocamidopropyl dimethyl. Amin, cocamidopropyl ethyldimonium etosulfate, cocamidopropyltrimonium chloride, behenamidepropyldimethylamine, isostearylamidepropyldimethylamine, stearylamidepropyldimethylamine, quaternium-33, undecyleneamidepropyltrimonium metosulfate, etc. Can be mentioned.

Examples of the ionic surfactant having a hydroxyl group in the molecule include castor oil monosulfate, castor oil monophosphate, sorbitan fatty acid ester sulfate, sorbitan fatty acid ester phosphate, sorbitol fatty acid ester sulfate, and sorbitol fatty acid. Ester phosphate, sucrose fatty acid ester sulfate, sucrose fatty acid ester phosphate, polyoxyalkylene sorbit oil ether monosulfate, polyoxyalkylene syrup oil ether monophosphate, polyoxyalkylene sorbitan fatty acid ester sulfate, polyoxyalkylene sorbitan fatty acid ester phosphate, polyoxyalkylene Examples thereof include glycerin ether monosulfate and polyoxyalkylene glycerin ether monophosphate.

Examples of the ionic surfactant having a hydroxyl group in the molecule include amphoteric surfactants such as N, N-di (β-hydroxyalkyl) N-hydroxyethyl-N-carboxyalkylammonium betaine and N-β. -Hydroxyalkyl-N, N-dipolyoxyalkylene-N-carboxyalkylammonium betaine, N-alkyl-N, N-di (polyoxyalkylene) amine and dicarboxylic acid monoester, N- (polyoxyethylene)- N', N'-di (polyoxyethylene) aminoalkyl-N-alkyl-N-sulfoalkylammonium betaine, N, N-di (polyoxyethylene) -N-alkyl-N-sulfoalkylammonium betaine, N- (Β-Hydroxyalkylaminoethyl) -N- (β-hydroxyalkyl) aminoethylcarboxylic acid, N, N'-bis (2-hydroxyalkyl) -N, N'-bis (carboxyethyl) ethylenediamine salt, N- Examples thereof include (β-hydroxyalkyl) -N', N'-di (polyoxyethylene) -N-carboxyethylethylenediamine salt and the like.

The ionic surfactant having a hydroxyl group in the molecule is easily compatible with the polyisocyanate (a) and the polyether polyol (b), and is cationic from the viewpoint of maintaining a good appearance of the coating film. The surfactant of the above is preferable, the compound represented by the general formula (1) is more preferable, and ricinolamidepropylethyldimonium etosulfate is further preferable.

Anionic surfactants and / or amphoteric tensides, which do not have a reactive group with the isocyanate group, have, as the reactive group, a hydroxyl group, an amino group, a carboxyl group, etc. in the molecule of the surfactant. It is a surfactant having no epoxy group or thiol group. The anionic and / or amphoteric surfactants having no reactive group with the isocyanate group may be used alone or in combination of two or more.

（一般式（２）中、Ｒ^１およびＲ^２は、独立して、直鎖または分岐鎖を有するアルキル基を表し、Ｒ^１およびＲ^２の合計の炭素数は１０以上３０以下であり、Ｍは水素原子、アルカリ金属原子、アンモニウム基、アルキルアンモニウム基またはアルカノールアンモニウム基を表す。）で表されるサクシネート型アニオン性界面活性剤；アニオン性フッ素系界面活性剤などが挙げられる。 Examples of the anionic surfactant having no reactive group with the isocyanate group include fatty acid salts such as sodium oleate and potassium oleate; higher alcohol sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; and dodecylbenzene. Alkylbenzene sulfonates such as sodium sulfonate, sodium alkylnaphthalene sulfonate and alkylnaphthalene sulfonates; sodium naphthalene sulfonate formalin condensate; general formula (2):

(In the general formula (2), R ¹ and R ² independently represent an alkyl group having a straight chain or a branched chain, ^{and the total number of carbon atoms of R 1} and R ² is 10 or more and 30 or less, and M Represents a hydrogen atom, an alkali metal atom, an ammonium group, an alkylammonium group, or an alkanolammonium group). Examples thereof include a succinate-type anionic surfactant; an anionic fluorine-based surfactant.

In the succinate-type anionic surfactant, in the general formula (2), ^{the total carbon number of R 1} and R ² is preferably 12 or more, more preferably 14 or more, and 24 or less. It is preferably 20 or less, and more preferably 20 or less. Further, in the general formula (2), M is preferably an alkali metal atom, an ammonium group, an alkylammonium group or an alkanolammonium group, and more preferably an alkali metal atom.

Examples of the succinate-type anionic surfactant include sodium dihexyl sulfosuccinate, sodium di-2-ethylhexyl sulfosuccinate, ammonium dilauryl sulfosuccinate, and the like, with sodium di-2-ethylhexyl sulfosuccinate being preferred. ..

Examples of the anionic fluorine-based surfactant include perfluoroalkyl carboxylic acid salt, perfluoroalkyl sulfonate, and perfluoroalkyl phosphate ester.

Examples of the amphoteric tenside agent having no reactive group with the isocyanate group include fatty acid type amphoteric ionic surfactants such as dimethylalkyllaurylbetaine and dimethylalkylstearylbetaine; and sulfonic acid type such as dimethylalkylsulfobetaine. Amphoteric ionic surfactants; amphoteric fluorine-based surfactants and the like can be mentioned.

Examples of the amphoteric fluorine-based surfactant include peroloalkyl betaine and the like.

The anionic fluorine-based surfactant and the amphoteric fluorine-based surfactant may have a straight-chain or branched-chain perfluoroalkyl group, but are preferably branched-chain, and are preferably branched-chain perfluoro. It is more preferably an alkenyl group, and further preferably a branched-chain perfluoroalkyl group represented by the following general formula (3) or (4).

Examples of the fluorine-based surfactant having a perfluoroalkyl group of the branched chain include sodium perfluoroalkenyloxybenzenesulfonate (manufactured by Neos Co., Ltd., trade name: phenylgent 100, trade name: phenylgent 110) and per. Anion type such as fluoroalkenyloxybenzyl phosphonic acid (manufactured by Neos Co., Ltd., trade name: phenylgent 140A), sodium perfluoroalkenyloxyphenylsulfonyl-N-methylcarboxylic acid (manufactured by Neos Co., Ltd., trade name: phenylgent 150) An androgynous type such as fluoroalkyl betaine (manufactured by Neos Co., Ltd., trade name: phenylgent 400S, trade name: phenylgent 400SW) can be mentioned.

Further, the urethane coating composition of the present invention can contain a silicone oil (d) having an HLB of 10 to 18. By containing the silicone oil (d), the smoothness of the cured coating film can be improved. Further, by using the silicone oil (d), long-term anti-fog durability can be improved. HLB (hydrophilic-lipophilic balance, Hydrophilic-Lypophilic Balance) indicates the molecular weight of the hydrophilic group portion in the total molecular weight of the surfactant. The HLB is determined by Griffin's formula. The silicone oil (d) may be used alone or in combination of two or more.

As the silicone oil (d), a compound having a structure in which the side chain and / or the hydrocarbon group at the terminal of the silicone oil is substituted with an organic group is preferable. Examples of the organic group include a polyether group, a long-chain alkyl group, a higher fatty acid ester group, and the like, and among them, a polyether group is preferable.

As the polyether group, for example, a polyethyleneoxy group, a polypropyleneoxy group, an ethyleneoxy group (EO) and a propyleneoxy group (trimethylethyleneoxy group or propane-1,2-diyloxy group; PO) are blocked or randomly formed. Examples include the added polyalkyleneoxy group.

The HLB of the silicone oil (d) is preferably 12 or more from the viewpoint of improving the antifogging property of the cured coating film, and is preferably 16 or less from the viewpoint of enhancing compatibility with each component in the urethane coating composition. ..

Examples of the silicone oil (d) include polyether-modified organopolysiloxane (HLB value = 12, manufactured by Shinetsu Chemical Industry Co., Ltd., trade name: KF-642), polyether-modified organopolysiloxane (HLB value = 14,). Examples thereof include Shin-Etsu Chemical Industry Co., Ltd., trade name: KF-640), polyether-modified organopolysiloxane (HLB value = 12, manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name: KF-351A) and the like.

The urethane coating composition of the present invention can contain a polycaprolactone polyol (e). The polycaprolactone polyol (e) has a number average molecular weight of 300 or more and 1800 or less. By containing the polycaprolactone polyol (e), the scratch resistance of the cured coating film can be improved. The polycaprolactone polyol (e) may be used alone or in combination of two or more. The number average molecular weight can be calculated from the hydroxyl value of the polycaprolactone polyol (e).

The polycaprolactone polyol (e) is a compound obtained by ring-opening polymerization of a polyfunctional alcohol such as glycerin or pentaerythritol and ε-caprolactone, and is a polycaprolactone diol, polycaprolactone triol, polycaprolactone tetraol, or poly. Caprolactone hexaol and the like can be mentioned.

The number average molecular weight of the polycaprolactone polyol (e) is preferably 400 or more, more preferably 450 or more, and cured, from the viewpoint of enhancing compatibility with each component in the urethane coating composition. From the viewpoint of improving the scratch resistance of the coating film, it is preferably 1500 or less, and more preferably 1000 or less. The number of hydroxyl groups per molecule of the polyether polyol (b) is preferably 3 or more from the viewpoint of improving the scratch resistance of the cured coating film, and each component in the urethane coating composition. From the viewpoint of enhancing compatibility with, it is preferably 6 or less.

The urethane coating composition of the present invention can contain a reaction retarder (f) which is a carboxylic acid and / or an inorganic acid. The reaction delaying agent (f) may be used alone or in combination of two or more.

Examples of the reaction retarder (f) include organic acids such as formic acid, propionic acid, benzoic acid, phthalic acid, oxalic acid and succinic acid; and inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid.

Hereinafter, the blending amount of each component of the urethane coating composition of the present invention will be described. Hereinafter, the polyisocyanate (a) is also referred to as a component (a), and components other than the component (a) (for example, (b)) are also referred to in the same manner.

The component (a) is 30% by weight or more and 60% by weight or less in the total weight of the components (a) to (c). The component (a) is preferably 40% by weight or more based on the total weight of the components (a) to (c) from the viewpoint of improving the scratch resistance of the cured coating film, and the cured coating film. From the viewpoint of increasing flexibility, it is preferably 50% by weight or less.

The component (b) is 35% by weight or more and 65% by weight or less in the total weight of the components (a) to (c). The component (b) is preferably 40% by weight or more based on the total weight of the components (a) to (c) from the viewpoint of improving the antifogging property of the cured coating film, and the cured coating film. From the viewpoint of improving scratch resistance, it is preferably 50% by weight or less.

The component (a) and the component (b) are preferably blended with an equivalent ratio of the isocyanate group of the component (a) / the hydroxyl group of the component (b) of 0.2 or more and 4 or less, preferably 0.3 or more. More preferably, it is blended in an amount of 2.5 or less.

The component (c) is an anionic surfactant having no reactive group between an ionic surfactant having a hydroxyl group in the molecule and an isocyanate group in the total weight of the components (a) to (c). The total weight of the agent and / or amphoteric surfactant is 1.0% by weight or more and 10% by weight or less. The component (c) is preferably 2% by weight or more, preferably 3% by weight or more, based on the total weight of the components (a) to (c), from the viewpoint of improving the antifogging property of the cured coating film. It is more preferable, and it is preferably 8% by weight or less from the viewpoint of enhancing the compatibility with each component in the urethane coating composition and from the viewpoint of imparting transparency to the cured coating film.

In the component (c), the weight ratio of the anionic surfactant and / or amphoteric surfactant having no reactive group with the isocyanate group to the ionic surfactant having a hydroxyl group in the molecule is 0. It is preferably 0.1 or more, more preferably 1.0 or more, preferably 5.0 or less, and more preferably 4.0 or less.

When the urethane coating composition contains the component (d), the component (d) increases the smoothness of the cured coating film in terms of the total weight of the components (a) to (d). It is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, and from the viewpoint of enhancing compatibility with each component in the urethane coating composition, and antifogging of the cured coating film. From the viewpoint of improving the properties, it is preferably 3% by weight or less, more preferably 2% by weight or less, and further preferably 1% by weight or less.

When the urethane coating composition contains the component (e), the component (e) is a phase with each component in the urethane coating composition in the total weight of the components (a) to (e). From the viewpoint of increasing the solubility and improving the antifogging property of the cured coating film, it is preferably 10% by weight or less, and more preferably 5% by weight or less. If the component (e) is 0.5% by weight or more based on the total weight of the components (a) to (e), the scratch resistance of the cured coating film can be expected to be improved.

When the urethane coating composition contains the component (e), the component (a), the component (b) and the component (e) are the isocyanate group of the component (a) / {(b) component and ( e) The equivalent ratio of the total hydroxyl groups of the components} is preferably 0.2 or more and 4 or less, and more preferably 0.3 or more and 2.5 or less.

When the urethane coating composition contains the component (f), the component (f) is the total weight of the components (a) to (d) and (f), or the components (a) to (f). ) The total weight of the components is preferably 5% by weight or less, and preferably 3% by weight or less. The component (f) is 0.1% by weight or more based on the total weight of the components (a) to (d) and (f) or the total weight of the components (a) to (f). If so, the effect of suppressing the urethane curing reaction (improvement of the pot life of the urethane coating composition) can be expected.

The urethane coating composition of the present invention can be prepared by diluting with an organic solvent.

Examples of the organic solvent include alcohol-based, carboxylic acid ester-based, ketone-based, amide-based, ether-based, aliphatic and aromatic hydrocarbon-based solvents. Examples of the alcohol solvent include methanol, isopropyl alcohol, n-butanol, diacetone alcohol, 2-methoxyethanol (methylcellosolve), 2-ethoxyethanol (ethylcellosolve), 2-butoxyethanol (butylcellosolve), and tertiary amyl. Alcohol and the like can be mentioned. Examples of the carboxylic acid ester solvent include ethyl acetate, n-propyl acetate, butyl acetate, butyl formate and the like. Examples of the ketone solvent include methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone and the like. Examples of the amide-based solvent include dimethylformamide and dimethylacetamide. Examples of the ether solvent include diethyl ether, methoxytoluene, 1,2-dimethoxyethane, 1,2-dibutoxyethane, 1,1-dimethoxymethane, 1,1-dimethoxyethane, 1,4-dioxane, and tetrahydrofuran. And so on. Examples of the aliphatic and aromatic hydrocarbon solvents include hexane, pentane xylene, toluene, benzene and the like. The organic solvent may be used alone or in combination of two or more. As the organic solvent, a solvent obtained by mixing a polar solvent such as diacetone alcohol or tertiary amyl alcohol with a carboxylic acid ester and / or a ketone solvent is preferable from the viewpoint of solubility, volatility and adhesion.

The isocyanate group of the polyisocyanate (a) reacts with the hydroxyl group of the polyether polyol (b) and the hydroxyl group of the polycaprolactone polyol (e) to form a urethane bond. A known catalyst can be added to the reaction to form the urethane bond, if necessary. Known catalysts include, for example, triethylamine, tetra (2-ethylhexyl) titanate, di-n-butyltin dilaurate, 1,4-diazabicyclo [2.2.2] octane and the like. When these catalysts are used, the amount used is usually 0.001 to 10 parts by weight with respect to 100 parts by weight of the polyisocyanate (a). The catalysts may be used alone or in combination of two or more.

The urethane coating composition of the present invention contains, if necessary, a stabilizer such as an ultraviolet absorber, an antioxidant, a light stabilizer, a colorant, a flame retardant, an isocyanate compound other than the polyisocyanate (a), and the poly. Polyols other than the ether polyol (b) and the polycaprolactone polyol (e), and leveling agents other than the silicone oil (d) can be used, but with respect to a total of 100 parts by weight of the components (a) to (c). , 0.1 to 10 parts by weight is preferable.

<Curing coating>
The urethane coating composition of the present invention can form a cured coating film on the surface of the substrate by coating the substrate with a coating method performed in ordinary paints and curing by heating.

As the base material, a known resin base material (member) can be used regardless of the type. Examples of the resin base material (member) include polymethylmethacrylate resin, polycarbonate resin, polystyrene resin, acrylonitrile / styrene copolymer resin, polyvinyl chloride resin, acetate resin, ABS resin, polyester resin, and polyamide resin.

The method for coating the urethane coating composition of the present invention on the resin base material (member) is not particularly limited, and is a bar coater coating, a brush coating, a sink coating, a dip coating, a spray coating, a spin coating, and a flow coating. Etc., a known method can be adopted.

The temperature at which the urethane coating composition of the present invention is heat-cured is preferably 60 ° C. or higher and 150 ° C. or lower, more preferably 80 ° C. or higher and 130 ° C. or lower, depending on the heat resistance and thermal deformability of the base resin used. It may be adjusted as appropriate. The heating time varies depending on the heating temperature, but is about several minutes to several hours.

The film thickness of the cured coating film is preferably 1.0 μm or more, more preferably 3.0 μm or more, from the viewpoint of improving the antifogging property of the cured coating film. The film thickness of the cured coating film is preferably 30 μm or less, more preferably 20 μm or less, from the viewpoint of enhancing the smoothness of the cured coating film.

Hereinafter, the present invention will be described with reference to Examples and the like, but the present invention is not limited to these.

The raw materials used in each Example and Comparative Example are as follows.
<Raw materials>
<Polyisocyanate (a)>
a-1: 1,3-bis (isocyanatomethyl) cyclohexane and trimethylolpropane adduct (solid content 75% by weight, ethyl acetate 25% by weight, isocyanate group content to solution 11.0%, Mitsui Chemicals, Inc. Made by the company, Takenate D-120N)
a-2: Adduct of isophorone diisocyanate and trimethylolpropane (solid content 75% by weight, ethyl acetate 25% by weight, solution isocyanate group content 11.0%, manufactured by Mitsui Chemicals, Inc., Takenate D-140N)
<Polyester polyol (b)>
b-1: Polyoxyethylene glyceryl ether (solid content 100%, number of hydroxyl groups per molecule 3, number average molecular weight 750, manufactured by NOF CORPORATION, Uniox G750)
b-2: Polyoxyethylene glyceryl ether (solid content 100%, number of hydroxyl groups per molecule 3, number average molecular weight 450, manufactured by NOF CORPORATION, Uniox G450)
b-3: Polyoxypropylene glyceryl ether (solid content 100%, number of hydroxyl groups per molecule 3, number average molecular weight 1500, manufactured by Sanyo Chemical Industries, Ltd., Sanniks GP1500)
<Surfactant (c)>
c-1: Ricinol amidopropyl ethyldimonium etosulfate (100% solid content, VANTAGE Specialty Ingredient, Inc., Lipoquat R)
c-2: Sodium di-2-ethylhexyl sulfosuccinate c-3: Anionic fluorine-based surfactant (solid content 100%, sodium sulfonic acid salt, manufactured by Neos Co., Ltd., Futergent 100)
c-4: Amphoteric fluorine-based surfactant (solid content 50%, manufactured by Neos Co., Ltd., Futergent 400SW)
<Silicone oil (d)>
d-1: Polyether-modified organopolysiloxane (HLB value = 12, KF-642 manufactured by Shin-Etsu Chemical Co., Ltd.)
d-2: Polyether-modified organopolysiloxane (HLB value = 14, KF-640 manufactured by Shin-Etsu Chemical Co., Ltd.)
<Polycaprolactone polyol (e)>
e-1: Polycaprolactone triol (100% solid content, 3 hydroxyl groups per molecule, number average molecular weight 800, manufactured by Daicel Corporation, Praxel 308)
<Reaction retarder (f)>
f-1: Benzoic acid <Other ingredients>
b'-1: Polyethylene glycol (100% solid content, 2 hydroxyl groups per molecule, number average molecular weight 200, manufactured by Tokyo Chemical Industry Co., Ltd., PEG200)
b'-2: Polyethylene glycol (100% solid content, 2 hydroxyl groups per molecule, number average molecular weight 2000, manufactured by Tokyo Chemical Industry Co., Ltd., PEG2000)
c'-1: Nonionic fluorine-based surfactant (solid content 100%, manufactured by Neos Co., Ltd., Futergent 215M)
c'-2: Cationic fluorine-based surfactant (100% solid content, quaternary ammonium salt (I salt or Br salt), manufactured by Neos Co., Ltd., Futergent 300)
<Organic solvent>
Diacetone alcohol (DAA)
Ethyl acetate

<Preparation of urethane paint composition>
<Examples 1 to 15, Comparative Examples 1 to 9>
The above raw materials were blended in the ratios shown in Tables 1 and 2, and 0.5 parts by weight of di-n-butyltin dilaurate was added as a catalyst to 100 parts by weight of polyisocyanate, respectively, and compared with Examples. An example urethane coating composition was obtained. In the formulation of the raw materials, the component (a) was added and mixed at the end.

Each of the obtained urethane coating compositions was placed on a polycarbonate resin plate (7.5 cm × 10 cm × 2 mm, Iupilon manufactured by Mitsubishi Gas Chemical Company, Ltd.) using a bar coater so that the film thickness after curing was about 8 μm. The coating was carried out and heat-cured in an oven set at 120 ° C. for 30 minutes to obtain a resin base material (member) having a cured coating film. Evaluation was performed by the following test method. The results are shown in Tables 1 and 2.

<Evaluation of appearance>
The surface of the cured coating film was visually judged and evaluated according to the following evaluation criteria.
◯: Normal ×: There is an abnormality such as opacity or whitening, or it is not smooth.

<Evaluation of scratch resistance>
Steel wool (# 0000) with a load of 500 g is placed on the surface of the cured coating film, tested under the test conditions of 11 reciprocations with a rubbing tester, and then tested with a haze meter (NDH5000 manufactured by Nippon Denshoku Industries Co., Ltd.). The haze (%) of the resin member having the cured coating film was measured and evaluated according to the following evaluation criteria.
◯: Haze value after test is less than 10 ×: Haze value after test is 10 or more

<Evaluation of adhesion>
After cross-cutting the cured coating film into 10 × 10 squares (1 mm intervals), a cellophane tape peeling test was performed, and the remaining squares were visually confirmed.
◯: No peeling ×: With peeling

<Evaluation of initial anti-fog property>
The surface of the cured coating film was exposed to warm steam at 50 ° C. for 1 minute in a constant temperature room at 25 ° C., and the presence or absence of fogging was visually evaluated according to the following evaluation criteria.
⊚: Water film is formed quickly ○: Water film is formed after momentary cloudiness ×: Cloudiness occurs

<Evaluation of anti-fog after water resistance>
A resin base material having a cured coating film was immersed in distilled water at room temperature for 1 hour, then taken out and allowed to stand at room temperature for 1 hour. After that, the above-mentioned initial anti-fog property evaluation test was conducted to confirm the presence or absence of fogging.
⊚: Water film is formed quickly ○: Water film is formed after momentary cloudiness ×: Cloudiness occurs

<Evaluation of anti-fog after wiping>
A waste cloth (BEMCOT M-3II, 250 mm × 250 mm, manufactured by Ozu Corporation) impregnated with about 5 ml of distilled water is placed on the surface of the cured coating film and reciprocated three times. Further, the resin base material (member) having the cured coating film is allowed to stand in a room at 25 ° C. and 50% RH for 1 hour, and then the surface of the cured coating film is exposed to steam at 50 ° C. for 5 minutes in a constant temperature room at 25 ° C. Exposed. After repeating the operation 5 times, the presence or absence of fogging was visually evaluated according to the following evaluation criteria. When the surfactant is present only on the surface of the cured coating film, the surfactant is wiped off by a waste cloth, and fogging tends to occur easily.
⊚: Water film is formed promptly in the 5th evaluation ○: Water film is formed after momentary cloudiness in the 5th evaluation ×: Cloudiness occurs in the 5th evaluation

Claims (6)

A urethane coating composition containing a polyisocyanate (a), a polyether polyol (b), and a surfactant (c).
The polyisocyanate (a) is a derivative of at least one diisocyanate selected from the group consisting of a burette body, an adduct body, an isocyanurate body, and an allophanate body.
The polyether polyol (b) has a number average molecular weight of 300 or more and 1800 or less.
The surfactant (c) is an ionic surfactant having a hydroxyl group in the molecule and an anionic surfactant and / or an amphoteric surfactant having no reactive group with an isocyanate group.
In the total weight of the components (a) to (c), the component (a) is 30% by weight or more and 60% by weight or less, and the component (b) is 35% by weight or more and 65% by weight or less. c) A urethane coating composition having a component of 1% by weight or more and 10% by weight or less. Contains silicone oil (d) with an HLB of 10-18
The urethane coating composition according to claim 1, wherein the component (d) is 3% by weight or less based on the total weight of the components (a) to (d). Contains polycaprolactone polyol (e)
The polycaprolactone polyol (e) has a number average molecular weight of 300 or more and 1800 or less.
The urethane coating composition according to claim 2, wherein the component (e) is 10% by weight or less based on the total weight of the components (a) to (e). Contains a reaction retarder (f) which is a carboxylic acid and / or an inorganic acid.
A claim characterized in that the component (f) is 5% by weight or less based on the total weight of the components (a) to (d) and (f) or the total weight of the components (a) to (f). Item 2. The urethane coating composition according to Item 2 or 3. A cured coating film formed from the urethane coating composition according to any one of claims 1 to 4. A resin member having the cured coating film according to claim 5.