WO2021065324A1

WO2021065324A1 - Film coating agent

Info

Publication number: WO2021065324A1
Application number: PCT/JP2020/033423
Authority: WO
Inventors: 西村　文男; 聡哉渡邊; 汰玖哉吉岡; 直幹瀬尾
Original assignee: 第一工業製薬株式会社
Priority date: 2019-09-30
Filing date: 2020-09-03
Publication date: 2021-04-08
Also published as: JP7393173B2; JP2021054940A; KR20220070202A; CN114364760A; TW202115144A

Abstract

Provided is a film coating agent that exhibits excellent thermal yellowing resistance and adhesion to a substrate. This film coating agent contains an aqueous polyurethane dispersion in which a polyurethane resin is dispersed in water, the polyurethane resin being obtained by reacting a compound having one or more amino groups with an isocyanate group-terminated pre-polymer obtained by reacting a polyisocyanate and a polyol. The film coating agent is characterized in that: the polyol contains a polyol having one or more acidic groups; and in the aqueous polyurethane dispersion, the ratio of number of moles of amino groups/number of moles of isocyanate groups is one or more, which is the molar ratio of the number of moles of isocyanate groups in the isocyanate group-terminated pre-polymer and the number of moles of amino groups in the compound having one or more amino groups.

Description

Film coating agent

The present invention relates to a film coating agent.

Polyurethane aqueous dispersion is widely used as a raw material for paints and coating agents, for example, for interior and exterior of aircraft and automobiles, as a raw material for paints and coating agents for exterior walls and flooring of houses. Therefore, the polyurethane aqueous dispersion is required to be provided with a coating film having various properties (for example, hardness, strength, durability, etc.) depending on the intended use and purpose of use.

For example, Patent Document 1 describes (a) a polyisocyanate compound and (b) a number average molecular weight as a coating composition that can be easily reapplied or removed from an excess coating film after being applied to a base material. It is obtained by reacting one or more polyol compounds containing 400 to 3000 polycarbonate polyols, (c) acidic group-containing polyol compounds, and (d) isocyanato group blocking agents that dissociate at 80 to 180 ° C. (A). The polyurethane resin obtained by reacting the polyurethane prepolymer with the (B) chain extender having reactivity with the isocyanato group is dispersed in an aqueous medium, and the content ratio of urethane bond and the content ratio of urea bond. The total is 7 to 18% by weight based on the solid content, the content ratio of the carbonate bond is 15 to 40% by weight based on the solid content, and the content ratio of the isocyanate group to which the blocking agent is bound is based on the solid content. A coating composition containing an aqueous polyurethane resin dispersion, which is 0.2 to 3% by weight in terms of isocyanato group, is disclosed.

Japanese Unexamined Patent Publication No. 2015-7239

The coating composition is required to have heat resistance, especially heat-resistant yellowing, depending on its use and purpose, but the conventional coating composition is not sufficiently heat-resistant yellowing.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a film coating agent having excellent heat-resistant yellowing and adhesion to a substrate.

The present invention provides the following [1] to [3].
[1] A polyurethane aqueous dispersion in which a polyurethane resin obtained by reacting an isocyanate group-terminated prepolymer obtained by reacting a polyisocyanate and a polyol with a compound having one or more amino groups is dispersed in water. Amino group molar, which is the molar ratio of the isocyanate group of the isocyanate group-terminated prepolymer to the amino group of the compound having one or more amino groups, wherein the polyol contains a polyol having one or more acidic groups. A film coating agent containing a polyurethane aqueous dispersion having 1 or more moles of isocyanate groups.
[2] The film coating agent according to [1], wherein the polyurethane resin has a number average molecular weight of 3000 or more and 15000 or less.
[3] The film coating according to [1] or [2], wherein the compound having one or more amino groups is one or more selected from adipic acid dihydrazide, hydrazine, and ammonia. Agent.

The present invention can provide a film coating agent having excellent heat-resistant yellowing and adhesion to a substrate.

The film coating agent of the present invention contains a polyurethane aqueous dispersion. The polyurethane aqueous dispersion is a polyurethane in which a polyurethane resin obtained by reacting an isocyanate group-terminated prepolymer obtained by reacting a polyisocyanate and a polyol with a compound having one or more amino groups is dispersed in water. It is an aqueous dispersion, in which the polyol contains a polyol having one or more acidic groups, and is the molar ratio of the isocyanate group of the isocyanate group-terminated prepolymer to the amino group of the compound having one or more amino groups. , The number of moles of amino groups / the number of moles of isocyanate groups is 1 or more.

The polyisocyanate is not particularly limited, and a polyisocyanate generally used in the technical field can be used. Specific examples thereof include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates.

Aliphatic polyisocyanates include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2-methylpentane-1. , 5-Diisocyanate, 3-methylpentane-1,5-Diisocyanate and the like.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexanediisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis (isocyanatemethyl) cyclohexane. Can be mentioned.

Examples of the aromatic polyisocyanate include tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dibenzyldiisocyanate, and 1,5. -Naftylene diisocyanate, xylylene diisocyanate, 1,3-phenylenediocyanate, 1,4-phenylenediocyanate and the like can be mentioned.

Examples of the aromatic aliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene diisocyanate and the like.

Further, modified products such as dimers and trimers of these polyisocyanates and buretted isocyanates can be mentioned. These can be used alone or in combination of two or more.

Among the above polyisocyanates, one or more selected from aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic aliphatic polyisocyanates are preferable, and particularly aromatic aliphatic polyisocyanates, in terms of heat-resistant yellowing and light resistance. Polyisocyanate is preferred.

The above-mentioned polyol is composed of a polyol having one or more acidic groups and a polyol having no acidic group.

The above-mentioned polyol having no acidic group contains one or more selected from polyester polyol and polyether polyol.

The polyester polyol can be generally obtained by a condensation reaction between a multivalent carboxylic acid and a polyhydric alcohol.

The polyvalent carboxylic acid is not particularly limited, but specifically, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, schberic acid, azelaic acid, sebacic acid, 1,12-dodecanediocarboxylic acid. , Hexahydrophthalic acid, isophthalic acid, terephthalic acid, dimeric acid, halogenated phthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, hexahydroterephthalic acid, hexahydroisophthalic acid, 2 , 6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid anhydride, 4,4'-biphenyldicarboxylic acid, dialkyl esters of these, etc. Examples thereof include a basic acid, an acid anhydride corresponding thereto, and a polybasic acid such as pyromellitic acid. These polyvalent carboxylic acids can be used alone or in combination of two or more. Examples of α, β-unsaturated dibasic acid include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride and the like.

The polyhydric alcohol is not particularly limited, but specifically, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-. 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-2-butyl -1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonane Diol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, diethylene glycol, dipropylene glycol, dihydric alcohols such as triethylene glycol, glycerin, trimethylolpropane , Pentaerythritol, sorbitol and the like.

The above-mentioned polyether polyol is not particularly limited, and a polyether polyol generally used in the technical field can be used. Specifically, ethylene glycol, propylene glycol, propanediol, butanediol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, neopetyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol. , Dipropylene glycol, Tripropylene glycol, 1,4-Cyclohexanedimethanol, Bisphenol A, Bisphenol F, Bisphenol S, Hydrogenated bisphenol A, Dibromobisphenol A, 1,4-Cyclohexanedimethanol, Dihydroxyethyl terephthalate, Hydroquinone dihydroxyethyl Examples thereof include polyhydric alcohols such as ether, trimethylolpropane, glycerin and pentaerythritol, and oxyalkylene derivatives such as ethylene oxide, propylene oxide and butylene oxide.

In the present invention, a polyol having a vinyl group may be contained as the polyol for the purpose of improving the adhesion to the hard coat layer containing the UV curable resin and UV resistance. Specific examples of the above-mentioned polyol having a vinyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycerin monoallyl ether, and trimethylol. Examples thereof include propanedialyl ether and pentaerythritol triallyl ether. Of these, glycerin monoallyl ether is preferable in terms of UV resistance. The polyol having a vinyl group is preferably 1 part by mass or more, more preferably 10 parts by mass or more, based on 100 parts by mass of the polyurethane, in terms of improving adhesion to a hard coat layer containing a UV curable resin and UV resistance. .. On the other hand, 50 parts by mass or less is preferable, and 30 parts by mass or less is more preferable.

Polyesters other than the above polyester polyols and polyether polyols may be used as long as the effects of the present invention are not impaired. As the polyol other than the polyester polyol and the polyether polyol, specifically known polycarbonate, polyether ester, polyacetal, polyolefin, fluorine-based, vegetable oil-based and the like can be used. More specifically, 1,6-hexanediol carbonate polyol, 1,4-butanediol and 1,6-hexanediol carbonate polyol, 1,5-pentanediol and 1,6-hexanediol carbonate, 3 Carbonated polyols of -methyl-1,5-pentanediol and 1,6-hexanediol, carbonates of 1,9-nonanediol and 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol and 1, Carbonate of 6-hexanediol, carbonate of 1,4-cyclohexanedimethanol, polycaprolactone polyol, polyester polyol, polythioether polyol, polyacetal polyol, polytetramethylene glycol, polybutadiene polyol, Himashi Examples thereof include polyol compounds such as oil polyol, soybean oil polyol, fluorine polyol, and silicon polyol, and modified products thereof.

In the present invention, the content of the polyester polyol and / or the polyether polyol is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and the lower limit is 100 parts by mass or less with respect to 100 parts by mass of the polyol. It is preferably 60 parts by mass or less, and more preferably 60 parts by mass or less. When the content of the polyester polyol and / or the polyether polyol is within the above range, it is preferable in terms of refractive index and hardness.

The content ratio of the polyester polyol to the polyether polyol is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, based on 100 parts by mass of the polyester polyol. On the other hand, 200 parts by mass or less is preferable, and 120 parts by mass or less is more preferable. When the content ratio is within the above range, it is preferable in terms of refractive index, hardness, and heat resistance.

In the present invention, the polyol may contain a polyol having a number average molecular weight of 400 or less.

The polyol having a number average molecular weight of 400 or less is the polyol described below among the above-mentioned polyols. That is, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 3-methylpentanediol, 1 , 6-Hexanediol, 1,8-octanediol, 2-methyl-1,3-propanediol, bisphenol A, hydrogenated bisphenol A, cyclohexanedimethanol, glycerin, trimethylolpropane and the like. Of these, one or two selected from glycerin and trimethylolpropane are preferable in terms of solvent resistance.

The content of the polyol having the number average molecular weight of 400 or less is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, based on 100 parts by mass of the polyurethane resin. Further, 3 parts by mass or less is preferable, and 1 part by mass or less is more preferable. When the content is within the above range, it is preferable in terms of handling during urethane resin production.

Examples of the acidic group of the polyol having an acidic group include a carboxyl group and a salt thereof, a sulfonic acid group and a salt thereof, and the like.

Examples of the polyol having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dioxymaleic acid, 2,6-dioxybenzoic acid, 3, Examples thereof include carboxylic acid-containing compounds such as 4-diaminobenzoic acid, derivatives thereof, and salts thereof, as well as polyester polyols obtained by using them. Further, amino acids such as alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid and histidine, and carboxylic acids such as succinic acid, adipic acid, maleic anhydride, phthalic acid and trimellitic anhydride can also be mentioned.

Examples of the polyol having the above sulfonic acid group and its salt include 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfoisophthalic acid, sulfanic acid, 1,3-phenylenediamine-4. , 6-Disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid and other sulfonic acid-containing compounds and derivatives thereof, and polyester polyols, polyamide polyols, polyamide polyester polyols and the like obtained by copolymerizing these compounds can be mentioned. ..

By neutralizing these carboxyl groups or sulfonic acid groups to salt, the finally obtained polyurethane can be made water-dispersible. Examples of the neutralizing agent include non-volatile bases such as sodium hydroxide and potassium hydroxide, tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine and triethanolamine, and volatiles such as ammonia. Examples include bases. Neutralization can be performed before, during, or after the urethanization reaction.

As the neutralizing agent, an amine compound having a boiling point of 100 ° C. or lower is preferable. Specific examples thereof include tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine and triethanolamine, and volatile bases such as ammonia.

In the present invention, the polyol having the acidic group is preferably the polyol having the carboxyl group from the viewpoint of raw material supply stability and versatility, and 2,2-dimethylolpropionic acid is particularly preferable.

As the above-mentioned compound having one or more amino groups, one or more selected from hydrazines such as ammonia, hydrazine, carbodihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide and phthalic acid dihydrazide can be used. it can. As the compound having one or more amino groups, one or more selected from ammonia, hydrazine, and adipic acid dihydrazide are preferable from the viewpoint of heat-resistant yellowing, and adipic acid dihydrazide is more preferable.

The method for producing the aqueous polyurethane dispersion of the present invention is not particularly limited, but is generally based on the total number of hydroxyl groups contained in the polyol and the polyol having one or more acidic groups, in terms of chemical quantity. An equivalent ratio of 1: 0.85 to 1.1 of the total amount of isocyanate groups and hydroxyl groups of excess polyisocyanate is reacted without a solvent or in an organic solvent having no active hydrogen group to obtain an isocyanate group-terminated prepolymer. After synthesis, 1 or more so that the number of moles of amino groups / number of moles of isocyanate groups, which is the molar ratio of the isocyanate groups of the above isocyanate group-terminated prepolymer to the amino groups of the compound having one or more amino groups, is 1 or more. A polyurethane aqueous dispersion can be obtained by reacting a compound having an amino group of the above to neutralize the acidic group of the urethane prepolymer and performing dispersion emulsification in water. The dispersion emulsification may be carried out before the reaction of the isocyanate group-terminated prepolymer with the compound having one or more amino groups. Then, if necessary, the solvent used can be removed to obtain a polyurethane aqueous dispersion.

The molar ratio of the isocyanate group of the isocyanate group-terminated prepolymer to the amino group of the compound having 1 or more amino groups, that is, the number of moles of amino groups / the number of moles of isocyanate groups is 1 or more, but 1.05 or more is preferable. , 1.1 or more is more preferable. Further, 2.0 or less is preferable, and 1.25 or less is more preferable. When the equivalent ratio is within the above range, a film coating agent having excellent heat-resistant yellowing and adhesion to a substrate can be obtained.

The organic solvent having no active hydrogen group is not particularly limited, and specific examples thereof include dioxane, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, N-methyl-2-pyrrolidone, toluene, and propylene glycol monomethyl ether acetate. It is preferable to finally remove these hydrophilic organic solvents used in the reaction.

The number average molecular weight of polyurethane in the polyurethane aqueous dispersion in the present invention is 3000 or more and 16000 or less in terms of solvent resistance, substrate adhesion, and adhesion to UV curable resin (hard coat layer), but 4000 or more. 12000 or less is more preferable

The acid value of the polyurethane is preferably 20 mgKOH / g or more, and more preferably 30 mgKOH / g or more from the viewpoint of substrate adhesion. On the other hand, 50 mgKOH / g or less is preferable, and 40 mgKOH / g or less is more preferable.

The degree of cross-linking of the polyurethane is preferably 0.01 mol / Kg or more, more preferably 0.03 mol / Kg or more, from the viewpoint of substrate adhesion and solvent resistance. On the other hand, 1 mol / Kg or less is preferable, and 0.5 mol / Kg or less is more preferable.

The urethane bond amount of the polyurethane is preferably 2.0 mol / Kg or more, and more preferably 2.5 mol / Kg from the viewpoint of hardness, heat resistance, and substrate adhesion. On the other hand, 10.0 mol / Kg or less is preferable, and 7.5 mol / Kg or less is more preferable.

The film coating agent of the present invention preferably contains the above polyurethane with respect to 100 parts by mass of the film coating agent in terms of transparency, heat-resistant yellowing, substrate adhesion, and adhesion to a UV curable resin (hard coat layer). It contains 20 parts by mass or more, more preferably 50 parts by mass or more. Further, it is preferably contained in an amount of 90 parts by mass or less, more preferably 80 parts by mass or less.

The film coating agent of the present invention is a pigment, a thickener, an ultraviolet absorber, an antioxidant, a light stabilizer, a defoaming agent, a plasticizer, and a surface conditioner, if necessary, as long as the effects of the present invention are not impaired. , Other additives such as anti-settling agents can be included. One type of additive may be used alone, or two or more types may be used in combination.

The pigment is not particularly limited, but specifically, for example, inorganic pigments such as titanium dioxide, zinc oxide, iron oxide, calcium carbonate, barium sulfate, yellow lead, clay, talc, and carbon black, azo-based pigments, and diazo-based pigments. Organic pigments such as condensed azo type, thioindigo type, indanslon type, anthraquinone type, benzoimidazole type, phthalocyanine type, isoindolinone type, perylene type, quinacridone type, dioxane type, and diketopyrrolopyrrole type can be mentioned.

The thickener is not particularly limited, but specific examples thereof include at least one selected from the group consisting of synthetic polymers, cellulose and polysaccharides, and turpen emulsions (each alone or a mixture of two or more thereof).

Examples of the synthetic polymer include polyacrylic acids, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylic amide and the like. Examples of cellulose include ethyl cellulose, methyl cellulose, hydroxymethyl cellulose, carboxymethyl cellulose and the like. Examples of the polysaccharide include xanthan gum, guar gum, casein, gum arabic, gelatin, carrageenan, alginic acid, tragacanto gum, locust bean gum, pectin and the like.

Examples of the tarpen emulsion include a mousse-like emulsion obtained by emulsifying mineral tarpen and water with a nonionic surfactant.

The ultraviolet absorber is not particularly limited, and specific examples thereof include benzophenone type, benzotriazole type, cyanoacrylate type, salicylate type, and oxalic acid anilide type. Examples of the ultraviolet stabilizer include hindered amine compounds. More specifically, light stabilizers such as "TINUVIN622LD", "TINUVIN765" (above, manufactured by Ciba Specialty Chemicals), "SANOL LS-2626" and "SANOL LS-765" (above, manufactured by Sankyo). , "TINUVIN 328" and "TINUVIN 234" (all manufactured by Ciba Specialty Chemicals Co., Ltd.) and the like.

The antioxidant is not particularly limited, but specifically, "IRGANOX245", "IRGANOX1010" (all manufactured by Ciba Specialty Chemicals Co., Ltd.), "Sumilizer GA-80" (manufactured by Sumitomo Chemical Co., Ltd.) and 2, Examples thereof include 6-dibutyl-4-methylphenol (BHT).

The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Synthesis of polyester polyol (a-1)]
While bubbling nitrogen gas in a reaction vessel equipped with a thermometer, a nitrogen gas introduction tube and a stirrer, 16.76 parts by mass of maleic anhydride, 83.14 parts by mass of a bisphenol A-2EO adduct, and 0 dioctyltin. .1 part by mass was charged, the reaction temperature was set to 160 to 170 ° C. so that the column top temperature was 50 to 60 ° C., and the reaction was carried out until the acid value became 2.6 mgKOH / g or less, and the hydroxyl value was 98. A polyester polyol (a-1) having a weight average molecular weight of 1100 and 9 mgKOH / g was obtained. The average hydroxyl value of the polyol was measured according to JIS K 1557.

[Synthesis of polyester polyol (a-2)]
While bubbling nitrogen gas in a reaction vessel equipped with a thermometer, a nitrogen gas introduction tube and a stirrer, 17.05 parts by mass of succinic acid, 82.85 parts by mass of bisphenol A-2EO adduct, and dioctyltin 0. 1 part by mass is charged, the reaction temperature is set to 160 to 170 ° C. so that the column top temperature is 50 to 60 ° C., and the reaction is carried out until the acid value becomes 2.6 mgKOH / g or less, and the hydroxyl value is 98.5 mgKOH. A polyester polyol (a-2) having / g and a weight average molecular weight of 1100 was obtained.

<Synthesis of polyurethane aqueous dispersion>
[Example 1]
61.82 parts by mass of polyester polyol (a-1) (weight average molecular weight: 1100, hydroxyl value: 98.9 mgKOH / g) in a four-necked flask equipped with a stirrer, a reflux cooling tube, a thermometer and a nitrogen blowing tube. , 0.54 parts by mass of trimethylolpropane, 9.14 parts by mass of dimethylolpropionic acid, and 100 parts by mass of methylethylketone were added and sufficiently stirred and dissolved, and then 28.5 parts by mass of xylenedi isocyanate was added and the NCO content was 1.0%. The reaction was carried out at 75 ° C. until Then, this prepolymer solution was cooled to 45 ° C., 1.16 parts by mass of ammonia and 300 parts by mass of water were added as neutralizing agents and emulsified using a homomixer, and then 0.41 parts by mass of ammonia was added. The terminal block reaction was carried out at 30 ° C. for 30 minutes. The methyl ethyl ketone was distilled off from this resin solution under heating and reduced pressure to obtain a polyurethane aqueous dispersion having a solid content of 25%.

In [Example 2], [Example 8], and [Example 13] to [Example 15], [Example 1] except that the type and the amount of each raw material charged are changed as shown in Table 1 below. Each polyurethane aqueous dispersion was obtained by the same production as in the above.

[Example 3]
A 4-neck flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blowing tube, and an addition of 4 mol of ethylene oxide of bisphenol A (product name: New Pole BPE-20NK, manufactured by Sanyo Kasei Kogyo Co., Ltd., weight average molecular weight) : 400, hydroxyl value: 345 mgKOH / g) by 33.72 parts by mass, glycerin monoallyl ether (product name: Neoallyl E-10, manufactured by Osaka Soda Co., Ltd.) by 10.00 parts by mass, dimethylol propionic acid by 8. 40 parts by mass and 100 parts by mass of methyl ethyl ketone were added and sufficiently stirred and dissolved, and then 47.88 parts by mass of xylenedi isocyanate was added and reacted at 75 ° C. until the NCO content became 1.0%. Then, 4.15 parts by mass of adipic acid dihydrazide was added, and the terminal block reaction was carried out at 30 ° C. for 30 minutes. Then, 1.07 parts by mass of ammonia and 300 parts by mass of water were added as neutralizing agents, and the mixture was emulsified using a homomixer. Then, 10 parts by mass of adipic acid dihydrazide was added as an additive. The methyl ethyl ketone was distilled off from this resin solution under heating and reduced pressure to obtain a polyurethane aqueous dispersion having a solid content of 25%.

In [Example 4], [Example 6], [Example 7], [Example 9], [Example 11], and [Example 12], the types and amounts of each raw material are shown in Table 1 below. Production was carried out in the same manner as in [Example 3] except that the changes were made as shown, and each polyurethane aqueous dispersion was obtained.

[Example 5] and [Example 10] are the same as [Example 3] except that the type and the amount of each raw material charged are changed as shown in Table 1 below and adipic acid dihydrazide is not added as an additive. The same production was carried out to obtain each urethane aqueous dispersion.

[Comparative Example 1]
A 4-neck flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blowing tube, and an addition of 4 mol of ethylene oxide of bisphenol A (product name: New Pole BPE-20NK, manufactured by Sanyo Kasei Kogyo Co., Ltd., weight average molecular weight) : 400, hydroxyl value: 345 mgKOH / g) by 33.72 parts by mass, glycerin monoallyl ether (product name: Neoallyl E-10, manufactured by Osaka Soda Co., Ltd.) by 10.00 parts by mass, dimethylol propionic acid by 8. 40 parts by mass and 100 parts by mass of methyl ethyl ketone were added and sufficiently stirred and dissolved, and then 47.88 parts by mass of xylenedi isocyanate was added and reacted at 75 ° C. until the NCO content became 1.0%. Then, 8.94 parts by mass of triethylamine and 300 parts by mass of water were added as a neutralizing agent and emulsified using a homomixer, and stirring by the homomixer was continued to carry out a chain extension reaction with water. The methyl ethyl ketone was distilled off from this resin solution under heating and reduced pressure to obtain a polyurethane aqueous dispersion having a solid content of 25%.

[Comparative Example 2] was produced in the same manner as in [Comparative Example 1] except that the type and amount of each raw material were changed as shown in Table 1 below, and each polyurethane aqueous dispersion was obtained.

[Comparative Example 3]
A 4-neck flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blowing tube, and an addition of 4 mol of ethylene oxide of bisphenol A (product name: New Pole BPE-20NK, manufactured by Sanyo Kasei Kogyo Co., Ltd., weight average molecular weight) : 400, hydroxyl value: 345 mgKOH / g) by 33.72 parts by mass, glycerin monoallyl ether (product name: Neoallyl E-10, manufactured by Osaka Soda Co., Ltd.) by 10.00 parts by mass, dimethylol propionic acid by 8. 40 parts by mass and 100 parts by mass of methyl ethyl ketone were added and sufficiently stirred and dissolved, and then 47.88 parts by mass of xylenedi isocyanate was added and reacted at 75 ° C. until the NCO content became 1.0%. Then, 8.94 parts by mass of triethylamine and 300 parts by mass of water were added as a neutralizing agent and emulsified using a homomixer, 2.19 parts by mass of dihydrazide adipic acid was added, and stirring by the homomixer was continued. A chain extension reaction was carried out. The methyl ethyl ketone was distilled off from this resin solution under heating and reduced pressure to obtain a polyurethane aqueous dispersion having a solid content of 25%.

* 1: 2 mol adduct of ethylene oxide of bisphenol A (manufactured by Sanyo Chemical Industries, Ltd.)
* 2: Trimethylolpropane
* 3: Glycerin monoallyl ether (manufactured by Osaka Soda Co., Ltd.)
* 4: Dimethylolpropionic acid
* 5: Xylene diisocyanate
* 6: Dihydrazide adipic acid

[Evaluation of polyurethane aqueous dispersion]
Evaluation was performed using the following evaluation methods and evaluation criteria. The evaluation results are shown in Table 1.
<Appearance>
It was judged visually.
<Non-volatile content>
Measured according to JIS K 6828.
<pH>
It was evaluated according to JIS Z8802.
<Viscosity>
The viscosity at 25 ° C. was measured using a BM type viscometer (single cylindrical rotational viscometer) according to JIS Z8803. At that time, (a) the rotor rotation speed is measured as 60 rpm, and (b) when the measured value in (a) above is 8000 mPa · s or more, the rotor rotation speed is changed to 30 rpm for measurement, and (c). When the measured value in (b) above was 16000 mPa · s or more, the rotor rotation speed was changed to 12 rpm for measurement.
<Average particle size>
It was measured with MicrotracUPA-UZ152 (manufactured by Nikkiso Co., Ltd.), and a 50% average value was calculated as the particle size.

[Evaluation of heat-resistant yellowing]
The evaluation was performed as follows. The evaluation results are shown in Table 1.
(Evaluation of polyurethane aqueous dispersion)
The color of each polyurethane aqueous dispersion after being stored at 70 ° C. for 3 days was visually compared with the color before storage. The evaluation criteria are as follows.
⊚: No change ○: Slightly yellowed ×: Yellowed.
(Evaluation of film)
Each polyurethane aqueous dispersion was applied to a dry thickness of about 200 to 300 μm, dried at room temperature (25 ° C.) for 24 hours, and then dried at 50 ° C. for 3 hours and at 120 ° C. for 20 minutes to prepare a film. The color of the film after heating the prepared film at 200 ° C. for 2 hours was visually evaluated.
◎: No change ○: Slightly yellowed ×: Turned blackish brown

[Evaluation of adhesion]
The substrate (PET film (untreated)) was degreased with isopropyl alcohol. Next, the polyurethane aqueous dispersions obtained in the above Examples and Comparative Examples were applied with a bar coater so as to have a drying film thickness of 5 μm, and dried for 10 minutes using a hot air drying oven having an atmospheric temperature of 280 ° C. to test pieces. Was prepared, a 1 mm grid test was carried out, and evaluation was performed according to the following evaluation criteria.
◯: 100 out of 100 sections remain ×: 99 out of 100 sections remain

As shown in Table 1, a polyurethane aqueous dispersion in which a compound having an amino group was not reacted with the free NCO group of the urethane prepolymer and a polyurethane resin subjected to a chain extension reaction with water was dispersed in water (Comparative Examples 1 and 2). ) And the aqueous dispersion of the polyurethane resin in which the chain was extended with dihydrazide adipate, which is a compound having an amino group, resulted in worsening the heat-resistant yellowing of the film.

The film coating agent of the present invention can be used as a coating agent for PET films and the like, and is particularly useful as a film coating agent for optical applications.

Claims

A polyurethane aqueous dispersion in which a polyurethane resin obtained by reacting an isocyanate group-terminated prepolymer obtained by reacting a polyisocyanate and a polyol with a compound having one or more amino groups is dispersed in water. Amino group molars, which is the molar ratio of the number of moles of isocyanate groups of the above isocyanate group-terminated prepolymer to the molar ratio of amino groups of the above compound having one or more amino groups, wherein the polyol contains a polyol having one or more acidic groups. A film coating agent containing a polyurethane aqueous dispersion having 1 or more moles of isocyanate groups.
The film coating agent according to claim 1, wherein the polyurethane resin has a number average molecular weight of 3000 or more and 15000 or less.
The film coating agent according to claim 1 or 2, wherein the compound having one or more amino groups is one or more selected from adipic acid dihydrazide, hydrazine, and ammonia.