JPH0971720A - Self-emulsifiable polyisocyanate composition and water-based coating material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-emulsifiable polyisocyanate composition showing good stability of dispersion in water by mixing a hydrophilic polyisocyanate prepared by introducing a hydrophilic group into a specified polyisocyanate with an ionic surfactant. SOLUTION: This self-emulsifiable polyisocyanate composition is prepared by mixing a hydrophilic polyisocyanate prepared by introducing 2-50wt.% nonionic-hydrophilic-group-containing compound comprising 5-50 repeating ethylene oxide units into a polyisocyanate made from aliphatic and/or alicyclic diisocyanates with 0.5-20wt.% ionic surfactant and has an isocyanate content of 6-25wt.%, a weight-average molecular weight of 350-10,000 and a viscosity of 50-20,000mPa.s (25 deg.C) in a state substantially free from any solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a self-emulsifying polyisocyanate composition and a coating composition of a room temperature crosslinkable water-based two-component urethane comprising an aqueous emulsion and the self-emulsifying polyisocyanate composition. , Excellent in water resistance, mainly water-based paints for construction, water-based paints for automobiles, adhesives, building materials, water-based paints for household use, other coating agents, sealing agents, inks, casting materials, elastomers, foams, plastic raw materials, fiber treatment agents, etc. And a water-based coating composition that can be used for

[0002]

2. Description of the Related Art In recent years, guidelines regarding volatile organic compounds have become strict, and regulations have already been implemented in the United States, Germany, etc., and it is considered that regulations will be implemented in Japan in the near future. Therefore, it has been desired that the cold-crosslinkable two-pack urethane coating composition conventionally used as a solvent-based coating composition be converted to an aqueous system. However, the polyisocyanate used as a curing agent in the two-pack urethane coating composition is difficult to disperse in water, is also easily reactive with water, and has a problem that carbon dioxide is generated, and thus has self-emulsifying property, The development of polyisocyanates in which the reaction between isocyanate groups and water in a water-dispersed state is suppressed is under way.

JP-B-55-7472, JP-A-5-
JP-A-222150 proposes a self-emulsifying polyisocyanate obtained by introducing a nonionic hydrophilic group into polyisocyanate as a method for obtaining a polyisocyanate having self-emulsifying property. In addition, JP-A-6-17004
In the publication, in order to improve the dispersibility of the self-emulsifying polyisocyanate, it is proposed to specify an aqueous emulsion dispersion having emulsifying properties. Also, Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 48429/1994 and Japanese Patent Application Laid-Open No. 7-1130005, polyisocyanates in which a nonionic hydrophilic group and a lipophilic group are introduced are proposed in order to extend the pot life.

However, since the conventional self-emulsifying polyisocyanate composition shown above uses only the nonionic group as the hydrophilic component, the reactivity between the isocyanate group and water in the water-dispersed state is sufficient. I could not suppress it, and the pot life did not reach the level that can be practically used,
Further, the coating composition using the self-emulsifying polyisocyanate composition as a crosslinking component has a drawback that the coating film has low water resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a polyisocyanate compound which is excellent in water dispersion stability and in which the reactivity between an isocyanate group and water in a water dispersion state is suppressed, and excellent water resistance using the same. It is an object of the present invention to provide an aqueous coating composition that forms a coated film.

[0006]

Means for Solving the Problems The present inventors have found that a self-emulsifying polyisocyanate composition using an ionic surfactant and an aqueous coating composition comprising the polyisocyanate composition and an aqueous emulsion are The inventors have found that the problems can be solved and completed the present invention.

That is, in the present invention, 2 to 50% by weight of a nonionic hydrophilic group-containing compound consisting of 5 to 50 ethylene oxide repeating units is introduced into a polyisocyanate obtained from an aliphatic and / or alicyclic diisocyanate. It is obtained by mixing 0.5 to 20% by weight of an ionic surfactant with respect to the hydrophilic polyisocyanate, and the isocyanate group content in the state of containing substantially no solvent is 6 to 25% by weight. %, Weight average molecular weight of 350 to 10,000, viscosity of 50 to 20,000 m
The present invention relates to a self-emulsifying polyisocyanate composition having good water dispersion stability of Pa · s (25 ° C.),
Further, as the component (A), a hydroxyl value of 1 to 300 mg KOH
/ G, an aqueous emulsion having a particle diameter of 0.03 to 1.0 μm, and the above-mentioned self-emulsifying polyisocyanate composition as the component (B), and the component (A) and the component (B) are equivalent to isocyanate groups / hydroxyl groups. The present invention relates to a water-based coating composition having a ratio of 0.5 to 5.0.

Examples of the aliphatic and / or alicyclic diisocyanate used for the polyisocyanate used in the present invention include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, Examples thereof include hydrogenated xylene diisocyanate and 1,4-diisocyanate cyclohexane. Among them, hexamethylene diisocyanate, isophorone diisocyanate and hydrogenated xylene diisocyanate are industrially readily available and preferred.

The polyisocyanates obtained from the above aliphatic and / or alicyclic diisocyanates include:
Buret, isocyanurate, urethane,
It has a structure such as uretdione and allophanate. In the polyisocyanate composition, those having a buret structure have excellent adhesiveness, those having an isocyanurate structure have excellent weather resistance, and those having a urethane structure using an alcohol compound having a long side chain are elastic. Further, it has excellent extensibility, and those having a uretdione structure or an allophanate structure are characterized by low viscosity.

The hydrophilic polyisocyanate in the present invention is the above polyisocyanate into which 2 to 50% by weight of a nonionic hydrophilic group-containing compound consisting of 5 to 50 ethylene oxide repeating units is introduced. 5-
The nonionic hydrophilic group-containing compound consisting of 50 ethylene oxide repeating units is one containing 5 to 50 ethylene oxide repeating units in the polyalkylene oxide ether alcohol, and is particularly preferable when considering the water dispersion stability. Is polyethylene glycol monomethyl ether. When the number of repeating units of ethylene oxide is less than 5, the self-emulsifying ability cannot be exhibited, which is not preferable. If the number exceeds 50, the crystallinity of the hydrophilic polyisocyanate becomes high and it becomes solid, which is not preferable.

The amount of the hydrophilic group-containing compound introduced into the polyisocyanate used in the present invention is in the range of 2 to 50% by weight. If it is less than 2% by weight, the self-emulsifying ability cannot be exhibited, which is not preferable. If it exceeds 50% by weight, the hydrophilicity of the self-emulsifying polyisocyanate composition is too high, and the reaction between the isocyanate group and water during water dispersion cannot be suppressed, which is not preferable. The term "introduction" used in the present invention means
Reacting with the isocyanate group contained in polyisocyanate and incorporating in a polyisocyanate structure. As the introduction method, an aliphatic or alicyclic diisocyanate, or by mixing a polyisocyanate obtained from it and a polyalkylene ether alcohol,
A normal urethanization reaction may be performed.

The self-emulsifying polyisocyanate composition of the present invention refers to the above-mentioned hydrophilic polyisocyanate mixed with an ionic surfactant in the range of 0.5 to 20% by weight. Whether the ionic surfactant is anionic or cationic is uniquely determined by the neutralization method of the aqueous emulsion of the component (A). That is, it is necessary to use an anionic surfactant when the aqueous emulsion is neutralized with a base, and a cationic surfactant when neutralized with an acid. If the aqueous emulsion is not neutralized, either may be used.

Suitable anionic surfactants are carboxylate type, sulfate type, sulfonate type and phosphate type, for example, ammonium alkylbenzene sulfonate, sodium alkyl disulfate, sodium alkyl diphenyl ether disulfonate, sodium dialkyl sulfosuccinate. Etc. Suitable cationic surfactants are quaternary ammonium salts, pyridinium salts and imidazolinium salts, such as alkyltrimethylammonium bromide, alkylpyridinium bromide and imidazolinium laurate.

If the amount added is less than 0.5 parts by weight, the effect of water dispersion stability due to the mixing of the ionic surfactant is not exhibited, which is not suitable. If it exceeds 20 parts by weight, the dispersed particle size becomes too small, the pot life becomes short, and the components that do not participate in the crosslinking increase too much, which may cause weakening of the coating such as a coating film. Absent.

A feature of the present invention is that a nonionic hydrophilic group and an ionic surfactant are used in combination. By forming a protective film of a nonionic hydrophilic group and an ionic surfactant on the surface of the polyisocyanate oil droplets, the water dispersion stability and long pot life of the water-dispersed polyisocyanate of the present invention are achieved. . Japanese Examined Patent Publication No. 55-7472,
JP-A-5-222150, JP-A-6-17004
Japanese Patent Laid-Open No. 7-48429, Japanese Patent Laid-Open No. 7-11
In JP 3005, only nonionic hydrophilic groups are used.

The introduction of a nonionic hydrophilic group into polyisocyanate lowers the interfacial tension and is effective for improving the dispersibility in water. However, since the nonionic hydrophilic group has low protection against water, it easily allows water to enter the polyisocyanate, starts the reaction between water and the isocyanate group, and reduces the residual isocyanate ratio in a short time. , Can not achieve a long pot life that can be practically used. Further, only by mixing an ionic surfactant with a polyisocyanate in which a hydrophilic group has not been introduced, the dispersibility in water is poor, and it is possible to achieve water dispersion stability like the polyisocyanate compound of the present invention. Absent.

The technical feature of the present invention is that a strong ionic protective film is formed on the surface of polyisocyanate oil droplets by using an ionic surfactant in combination with polyisocyanate having a nonionic hydrophilic group. Yes, this prevents water from entering the polyisocyanate oil droplets,
The isocyanate groups in the polyisocyanate oil droplets can be protected from water. This can be achieved by the interaction between the nonionic hydrophilic group introduced into the polyisocyanate and the ionic surfactant.

In a system in which a polyisocyanate having only a nonionic hydrophilic group introduced therein is dispersed in water to which an anionic surfactant has been added, a water to which an anionic surfactant has been added when producing polyisocyanate oil droplets is used. It is not possible to achieve a long pot life because the oil is hugged inside the oil droplets. The isocyanate group content in the self-emulsifying polyisocyanate composition of the present invention is 8 to 25% by weight.
Range. If it is less than 8% by weight, there are disadvantages that the number of crosslinking points in the coating composition is small, the curing rate is lowered, or the coating such as a coating film becomes brittle. Further, the isocyanate group content is uniquely determined from the introduction amount and the molecular weight of the hydrophilic group-containing compound. Therefore, when the hydrophilic group necessary for having the self-emulsifying ability is introduced, the upper limit is necessarily 25% by weight or less. Becomes

The weight average molecular weight of the self-emulsifying polyisocyanate composition of the present invention is in the range of 350 to 10,000. When the hydrophilic group necessary for expressing the self-emulsifying ability is introduced, the weight average molecular weight is necessarily 350 or more. When it exceeds 10,000, the viscosity of the polyisocyanate becomes high and it becomes difficult to disperse it in water, which is not suitable.

The viscosity of the self-emulsifying polyisocyanate composition of the present invention is 50 to 20000 mPa · s (2
5 ° C.) range. When it exceeds 20,000 mPa · s, it is difficult to disperse it in water, which is not suitable. Considering dispersion in water, the lower the viscosity, the more desirable, but 50 mPa.
When it is less than m, a large amount of diisocyanate having a low crosslinking ability is contained, which is not preferable.

The self-emulsifying polyisocyanate composition of the present invention has a residual rate of isocyanate groups of 20 ° C. when dispersed in water.
It is necessary to be 50% or more in time. If it is less than 50%, the pot life of the aqueous coating composition is shortened, the water resistance of the coating such as a coating film is lowered, and the coating becomes brittle, which is not preferable. The suppression of the reaction between the water and the isocyanate group is achieved by the mutual effect of the ionic surfactant component mixed with the introduced hydrophilic group component. In addition, the water dispersion referred to in the present invention means a state in which the self-emulsifying polyisocyanate composition is dispersed in water so that the self-emulsifying polyisocyanate composition becomes an O / W type. It is created by mechanical stirring.

The self-emulsifying polyisocyanate composition of the present invention has good water dispersion stability. The water dispersion stability referred to in the present invention is the stability in water of the oil droplets of the self-emulsifying polyisocyanate composition dispersed in water by the above method. When the self-emulsifying polyisocyanate composition of the present invention is dispersed in water and left at 20 ° C. for 8 hours, no precipitation is observed. This is also achieved by the mutual effect of the introduced hydrophilic group component and the ionic surfactant mixed.

The self-emulsifying polyisocyanate composition of the present invention may be used after adding an organic solvent. The polyisocyanate mixed with an organic solvent has characteristics that the viscosity becomes low, the water dispersibility is improved, the residual rate of the isocyanate group at the time of water dispersion becomes high, and the pot life becomes long. In this case, it is necessary that the organic solvent does not have a functional group that reacts with an isocyanate group. In addition, the organic solvent must be compatible with the self-emulsifying polyisocyanate composition of the present invention. Furthermore, the solubility of water in organic solvents is 20 at 25 ° C.
It is preferably not more than wt%. When the solubility of water exceeds 20% by weight, water penetrates into the isocyanate oil droplets, so that a long pot life cannot be achieved.

The lower the solubility of water, the longer the pot life can be achieved. However, if it is too low, the compatibility with the polyisocyanate composition of the present invention decreases, and depending on the type of aqueous emulsion, the coating film may become cloudy. It is not preferable because it exists. The lower limit of the water solubility is difficult to set because it changes depending on the amount of the nonionic hydrophilic group introduced into the polyisocyanate of the present invention, the amount of the ionic surfactant mixed and the type of aqueous emulsion, but it is a strong guideline. Therefore, it can be said that 0.01% by weight or more is preferable.

Examples of the organic solvent added to the self-emulsifying polyisocyanate composition of the present invention include ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, methoxypropyl acetate,
3-methoxybutyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methyl propionate, butyl propionate, butyl butyrate, dioctyl adipate, ester compounds such as diisopropyl glutarate and diisopropyl ether,
Ether compounds such as dibutyl ether, dioxane and diethoxyethane, 2-pentanone, 3-pentanone, 2
-Hexanone, methyl isobutyl ketone 2-heptanone, 4-heptanone, diisobutyl ketone, isophorone, cyclohexanone, methyl cyclohexanone, and other ketone compounds; and benzene, toluene, xylene, ethylbenzene, butylbenzene, p-cymene, and other aromatic compounds. To be

The amount of the organic solvent added to the self-emulsifying polyisocyanate composition of the present invention is preferably in the range of 5 to 50% by weight. If it is less than 5% by weight, the merit of mixing an organic solvent, that is, the improvement of water dispersibility and the effect of extending the pot life cannot be seen, which is not preferable. If it exceeds 50% by weight, the amount of the volatile organic compound in the water-based coating composition of the present invention is undesirably increased.

The aqueous emulsion used as the component (A) in the present invention includes all those expressed as latex, emulsion and the like. For example, polyvinylidene chloride copolymer, polyvinyl chloride copolymer, vinyl acetate copolymer, urethane emulsion, acrylic emulsion, fluorine copolymer emulsion, styrene butadiene copolymer latex, acrylonitrile butadiene copolymer,
Examples thereof include rubber latex, polybutadiene copolymer, urethane acrylic emulsion and the like.

The hydroxyl value of the aqueous emulsion used in the present invention is in the range of 1 to 300 mgKOH / g. 1m
If it is less than gKOH / g, the number of cross-linking points in the coating composition is reduced, the curing rate is lowered, or the coating such as a coating film becomes brittle, which is not preferable. 300mg
If it exceeds KOH / g, on the contrary, there are too many crosslinking points, and the coating becomes hard and brittle, which is not preferable.

The particle size of the aqueous emulsion used in the present invention is in the range of 0.03 to 1.0 μm. 0.03μ
When it is less than m, the gloss of the obtained coating is lowered, which is not preferable. When it exceeds 1.0 μm, the stability of water dispersion of the aqueous emulsion is deteriorated, which is not preferable.

In the present invention, the equivalent ratio of isocyanate group / hydroxyl group of the aqueous emulsion of the component (A) and the self-emulsifying polyisocyanate composition of the component (B) is 0.5 to 5.
It is 0, preferably in the range of 1.0 to 3.0. 0.5
If it is less than the above range, the number of cross-linking points in the coating composition decreases, the curing rate decreases, or the coating such as a coating film becomes brittle, which is not preferable. If it exceeds 5.0, the coating becomes hard and brittle, which is not preferable.

The water-based coating composition containing the components (A) and (B) has a pot life of 6 at 20 ° C.
It must be more than time. What is pot life?
It means that no remarkable increase in viscosity and no foaming are observed in the water-based coating composition. It cannot be said that it can withstand practical use in less than 6 hours. This long pot life can be achieved by interaction with the ionic surfactant mixed with the introduced nonionic hydrophilic group.

From the above water-based coating composition,
The gel fraction of the coating film obtained under the coating conditions of 20 ° C. and 24 hours is 50% or more. If it is less than 50%, the water resistance is poor, which is not preferable. The key points that could achieve this are the isocyanate group content of the self-emulsifying polyisocyanate, the suppression of the reaction between water and isocyanate groups during water dispersion, and the high gel fraction within the particles of the aqueous emulsion. .

The self-emulsifying polyisocyanate composition of the present invention and the aqueous coating composition comprising the self-emulsifying polyisocyanate composition may contain a pigment, a dispersion stabilizer, and
A viscosity modifier, a leveling agent, a light stabilizer, an antioxidant, an ultraviolet absorber, a filler, a plasticizer, a lubricant, a curing acceleration catalyst and the like can be added.

Since the self-emulsifying polyisocyanate composition of the present invention suppresses the reaction of isocyanate groups with water in a water-dispersed state, it should achieve a long pot life when used in an aqueous coating composition. Can be done. Furthermore, the coating such as a coating film obtained from the water-based coating composition of the present invention has excellent water resistance. Therefore, it is possible to make water-based paints in which solvent-based polyurethane paints have been conventionally used, particularly paints for repainting building exteriors, automobile repair paints, plastic paints and the like. Further, it can be applied to a wide range of fields such as sealing agents, adhesives, inks, coating materials, casting materials, elastomers, foam and plastic raw materials, and fiber treatment agents.

[0035]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The measuring method used in the present invention is shown below. The isocyanate group content was determined by back titration with hydrochloric acid after neutralizing the isocyanate group with an excess of amine. The viscosity was measured at 25 ° C. and 60 rpm with a digital viscometer (manufactured by Tokyo Keiki Co., Ltd .; DVM-B type). The weight average molecular weight was determined using gel permeation chromatography (GPC).

When the weight average molecular weight of GPC is less than 2000, the column: G1000HXL from Tosoh Corp.,
G2000HXL, G3000HXL, Carrier: T
HF, detection method: parallax refractometer, data processor: Tosoh Co., Ltd. CP-8000, when weight average molecular weight is 2000 or more, column: Tosoh G2000HXL, G40
00HXL, G5000HXL, carrier: THF,
Inspection method: Parallax refractometer, data processor: Tosoh Corporation Chromatocoder 21 was used for measurement.

The aqueous dispersion was prepared by mixing sample: water at a weight ratio of 40:60 and stirring at 600 rpm for 10 minutes.
The water-based coating composition is prepared by adding a predetermined amount of a self-emulsifying polyisocyanate composition to an aqueous emulsion,
It was made by stirring at rpm for 10 minutes. The particle size is measured by an ultracentrifugal automatic particle size distribution measuring device (Horiba CAPC-70
0) was used. The gel fraction was obtained from the following formula by extracting about 0.1 g of the cured resin with 50 g of acetone. Gel fraction = (residual amount of solid content when resin is extracted with acetone for 24 hours / resin weight) × 100%

Example 1 Methoxypolyethylene glycol (MPG-081; trade name, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and ammonium alkylbenzene sulfonate (Newcol 210; trade name, solid content) 50%, manufactured by Nippon Emulsifier Co., Ltd.) was mixed at a solid content weight ratio of 3: 1 and water and solvent were removed by vacuum distillation. Burette type polyisocyanate (Duranate 24A-100; trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) (1000 g) and 200 g of the mixture of methoxypolyethylene glycol and ammonium alkylbenzenesulfonate obtained above were mixed, and urethanized at 90 ° C. for 2 hours. The reaction was carried out. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, having an isocyanate group content of 18.5%, a weight average molecular weight of 1000, and a viscosity of 3200 mPa · s. In addition, the residual rate of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was 90%.

Example 2 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M; trade name, solid content 70%). (Manufactured by Nippon Emulsifier Co., Ltd.) was mixed at a solid content weight ratio of 2: 1 and water and solvent were removed by vacuum distillation. Buret-type polyisocyanate (Duranate 24A-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) (1000 g) was mixed with 300 g of the mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above, and a urethanization reaction was performed at 90 ° C. for 2 hours. It was The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, had an isocyanate group content of 16.6%, a weight average molecular weight of 1100 and a viscosity of 4100 mPa · s. In addition, the water dispersion liquid
The residual ratio of the isocyanate group content when left at 6 ° C for 6 hours was 93%.

(Example 3) Methoxypolyethylene glycol (ethylene oxide repeating unit = 48.5)
And ammonium polyoxyethylene nonylphenyl ether sulfonate (Newcol 560SF; trade name, solid content 50%, manufactured by Nippon Emulsifier Co., Ltd.) were mixed at a solid content weight ratio of 4: 1 and water was distilled under reduced pressure. And the solvent was removed. Burette type polyisocyanate (Duranate 24A-100, manufactured by Asahi Kasei Corporation) 1000 g and 25 g of the mixture of methoxy polyethylene glycol and polyoxyethylene nonylphenyl ether ammonium sulfonate obtained above were mixed, and the mixture was mixed at 90 ° C. for 2 hours. Urethane reaction was performed. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, having an isocyanate group content of 21.6%, a weight average molecular weight of 880, and a viscosity of 2400 mPa · s.
The residual isocyanate group content rate when the aqueous dispersion was left at 20 ° C. for 6 hours was 91%.

(Example 4) Methoxy polyethylene glycol (MPG-130; trade name, ethylene oxide repeating unit = 9.4, manufactured by Nippon Emulsifier Co., Ltd.) and sodium polyoxyethylene tridecyl ether sulfonate (Newcol 1305SN, Solid content 30%, manufactured by Nippon Emulsifier Co., Ltd.) were mixed at a solid content weight ratio of 1: 1 and water and solvent were removed by vacuum distillation. Burette type polyisocyanate (Duranate 24A
-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 400 g of the mixture of polyethylene glycol and ammonium polyoxyethylene nonylphenyl ether sulfonate obtained above were mixed, and a urethanization reaction was carried out at 90 ° C. for 2 hours. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid having an isocyanate group content of 14.9%, a weight average molecular weight of 2000 and a viscosity of 18
000 mPa · s. In addition, the water dispersion liquid at 20 ° C 6
The residual isocyanate group content when left to stand for 78 hours was 78%.

Example 5 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and benzyl ammonium salt (Texnol R5 (50); trade name, solid content 50%) (Manufactured by Nippon Emulsifier Co., Ltd.) were mixed at a solid content weight ratio of 1: 1 and water and solvent were removed by vacuum distillation. Burette type polyisocyanate (Duranate 24A-100, manufactured by Asahi Kasei Corporation) 1
000 g and 300 g of a mixture of methoxypolyethylene glycol and benzyl ammonium salt obtained above
And were mixed, and a urethanization reaction was carried out at 90 ° C. for 2 hours. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, having an isocyanate group content of 16.4%, a weight average molecular weight of 950, and a viscosity of 4000 mPa · s. In addition, the residual rate of the isocyanate group content rate when the aqueous dispersion was left at 20 ° C. for 6 hours was 88%.

Example 6 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and ammonium alkylbenzene sulfonate (Newcol 210,
50% solid content, manufactured by Nippon Emulsifier Co., Ltd.) were mixed at a solid content weight ratio of 5: 2, and water and solvent were removed by vacuum distillation. 1000 g of isocyanurate type polyisocyanate (Duranate TPA-100; trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 700 g of the mixture of methoxypolyethylene glycol and ammonium alkylbenzenesulfonate obtained above are mixed, and 120
Urethane reaction was carried out for 2 hours at ℃. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid having an isocyanate group content of 11.4%, a weight average molecular weight of 1400 and a viscosity of 9600 mPa · s. Also,
When the aqueous dispersion was left at 20 ° C. for 6 hours, the residual ratio of the isocyanate group content was 82%.

Example 7 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70%, Japan emulsifier stock) (Manufactured by the company) were mixed at a solid content weight ratio of 2: 1 and water and solvent were removed by vacuum distillation. 1000 g of isocyanurate type polyisocyanate (Duranate TPA-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 300 g of the mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above are mixed and subjected to urethanization reaction at 100 ° C. for 2 hours. went. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, had an isocyanate group content of 16.6%, a weight average molecular weight of 1100 and a viscosity of 3000 mPa · s. In addition, the water dispersion liquid at 20 ° C
The residual rate of the isocyanate group content when left to stand for 6 hours was 88%.

Example 8 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70%, Japan emulsifier stock) (Manufactured by the company) was mixed at a solid content weight ratio of 3: 2, and water and a solvent were removed by vacuum distillation. 1000 g of urethane type polyisocyanate (Duranate E-402; trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 150 g of the mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above are mixed and urethanized at 100 ° C. for 2 hours. The reaction was carried out. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid having an isocyanate group content of 7.9%, a weight average molecular weight of 3600 and a viscosity of 1
It was 5000 mPa · s. In addition, the water dispersion liquid at 20 ° C
The residual rate of the isocyanate group content when left to stand for 6 hours was 94%.

Example 9 Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70%, Japan emulsifier stock) (Manufactured by the company) was mixed at a solid content weight ratio of 2: 1 and water and solvent were removed by vacuum distillation. HDI / IPDI mixed system burette type polyisocyanate (Duranate V-3000; trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) 1000 g, and 100 g of a mixture of the methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed at 100 ° C. The urethane reaction was carried out for 2 hours. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, had an isocyanate group content of 18.2%, a weight average molecular weight of 2000, and a viscosity of 16000 mPa · s. In addition, the residual rate of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was 80%.

Example 10 160 g of the self-emulsifying polyisocyanate composition obtained in Example 2 was mixed with 4 g of butyl acetate.
0 g (water solubility: 1.9 wt%) was added. The obtained self-emulsifying polyisocyanate composition was a pale yellow liquid, had an isocyanate group content of 13.3% and a viscosity of 230 mPa · s. In addition, the water dispersion liquid at 20 ° C 6
The residual rate of the isocyanate group content when left to stand for 95 hours was 95%.

(Example 11) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 160 mgKOH / g, acid value 6 mgK
OH / g, Tg 25 ° C., particle diameter 0.09 μm) and the self-emulsifying polyisocyanate obtained in Example 1 were mixed at an equivalence ratio of isocyanate groups and hydroxyl groups of 0.5 to obtain an aqueous coating composition. This water-based coating composition,
Even when left at 20 ° C. for 8 hours, viscosity increase and foaming were not observed. A coating film having a thickness of 40 μm was formed using this coating composition and cured at 20 ° C. and 65% RH for 24 hours to obtain a transparent coating film. The gel fraction was measured to be 79%, and no whitening of the coating film was observed even after immersion in water at 20 ° C. for 4 hours.

(Example 12) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 20 mgKOH / g, acid value 6 mgKO
H / g, Tg 10 ° C., particle size 0.08 μm) and Example 2
The self-emulsifying polyisocyanate obtained in 1. was mixed at an equivalence ratio of isocyanate groups and hydroxyl groups of 1.5 to obtain an aqueous coating composition. This water-based coating composition has 2
Even when left at 0 ° C. for 8 hours, viscosity increase and foaming were not observed. A coating film having a thickness of 40 μm was formed using this coating composition and cured at 20 ° C. and 65% RH for 24 hours to obtain a transparent coating film. The gel fraction measured was 84%, and no whitening of the coating film was observed even after immersion in water at 20 ° C. for 4 hours.

(Example 13) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 4 mgKOH / g, acid value 1 mgKOH
/ G, Tg of 10 ° C., particle diameter of 0.2 μm) and the self-emulsifying polyisocyanate obtained in Example 6 were mixed at an equivalence ratio of isocyanate groups and hydroxyl groups = 5.0 to obtain an aqueous coating composition. This water-based coating composition has a temperature of 20 ° C.
Even when left for 8 hours, viscosity increase and foaming were not observed.
When a coating film having a thickness of 40 μm was prepared using this coating composition and cured at 20 ° C. and 65% RH for 24 hours,
A transparent coating film was obtained. The gel fraction measured is 70%,
No whitening of the coating film was observed even after immersion in water at 20 ° C. for 4 hours.

(Example 14) Fluorine latex (hydroxyl value 10 mgKOH / g, acid value 2 mgKOH / g, Tg0
(° C, particle diameter 0.1 μm) and the self-emulsifying polyisocyanate obtained in Example 2 were mixed at an equivalence ratio of isocyanate groups and hydroxyl groups of 1.5 to obtain an aqueous coating composition.
The water-based coating composition had no increase in viscosity and no foaming even after standing at 20 ° C. for 8 hours. A coating film having a thickness of 40 μm is prepared using this coating composition,
When cured at 65 ° C. and 65% RH for 24 hours, a transparent coating film was obtained. The gel fraction measured was 77%, and no whitening of the coating film was observed even after immersion in water at 20 ° C. for 4 hours.

(Example 15) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 160 mgKOH / g, acid value 6 mgK
OH / g, Tg 25 ° C., particle size 0.09 μm) and the self-emulsifying polyisocyanate obtained in Example 10 were mixed at an equivalent ratio of isocyanate groups and hydroxyl groups of 1.5 to obtain an aqueous coating composition. The water-based coating composition had no increase in viscosity and no foaming even after standing at 20 ° C. for 8 hours. Using this coating composition, a thickness of 40μ
When a coating film of m was prepared and cured at 20 ° C. and 65% RH for 24 hours, a transparent coating film was obtained. The gel fraction is 84
%, And no whitening of the coating film was observed even after immersion in water at 20 ° C. for 4 hours.

Comparative Example 1 Methoxypolyethylene glycol (ethylene oxide repeating unit = 20.4)
150 g and 1000 g of isocyanurate type polyisocyanate (Duranate TPA-100, manufactured by Asahi Kasei Corporation) were mixed, and a urethanization reaction was carried out at 100 ° C. for 2 hours. The obtained polyisocyanate was a pale yellow liquid, the isocyanate group content was 18.7%, the weight average molecular weight was 1300, and the viscosity was 2800 mPa · s. The residual isocyanate group content was 0% when the aqueous dispersion was left at 20 ° C. for 4 hours.

Comparative Example 2 200 g of methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.2, manufactured by Nippon Emulsifier Co., Ltd.) and buret type polyisocyanate (Duranate 24)
A-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) (1000 g) were mixed and a urethane reaction was carried out at 90 ° C. for 2 hours. The polyisocyanate obtained was a pale yellow liquid, had an isocyanate group content of 18.3% and a weight average molecular weight of 120.
The viscosity was 0 and the viscosity was 2300 mPa · s. When the aqueous dispersion was left for 2 hours at 20 ° C, the residual isocyanate group content was 0%.

(Comparative Example 3) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 20 mgKOH / g, acid value 6 mgKOH
/ G, Tg of 10 ° C., particle diameter of 0.08 μm) and the self-emulsifying polyisocyanate obtained in Comparative Example 1 were mixed at an equivalence ratio of isocyanate groups and hydroxyl groups of 1.5 to obtain an aqueous coating composition. This water-based coating composition is 20
When left at 6 ° C for 6 hours, it solidified. A coating film having a thickness of 40 μm is prepared using this coating composition, and the temperature is 20 ° C. and 65% R.
When cured with H for 24 hours, a slightly hazy coating film was obtained. The gel fraction was 81% when measured, and the coating film was whitened when immersed in water at 20 ° C. for 4 hours.

(Comparative Example 4) Acrylic latex (styrene / methyl methacrylate / n-butyl acrylate copolymer, hydroxyl value 20 mgKOH / g, acid value 6 mgKOH
/ G, Tg of 10 ° C., particle diameter of 0.08 μm) and the self-emulsifying polyisocyanate obtained in Comparative Example 2 were mixed at an equivalence ratio of isocyanate groups and hydroxyl groups of 1.0 to obtain an aqueous coating composition. This water-based coating composition is 20
When left at 6 ° C for 6 hours, it solidified. A coating film having a thickness of 40 μm is prepared using this coating composition, and the temperature is 20 ° C. and 65% R.
When it was cured with H for 24 hours, a transparent coating film was obtained. The gel fraction was measured to be 84%, and the coating film was swollen and whitened when immersed in water at 20 ° C. for 4 hours.

[0057]

EFFECTS OF THE INVENTION The self-emulsifying polyisocyanate composition of the present invention has a long pot life when used in an aqueous coating composition because the reaction of isocyanate groups with water in a water-dispersed state is suppressed. You can do it.
Furthermore, the coating material such as a coating film obtained from the water-based coating composition of the present invention is excellent in water resistance and solvent resistance. Therefore,
Paint that used to use solvent-based polyurethane paint,
In particular, paint for repainting exterior building or paint for automobile repair,
It is possible to make plastic paints and the like water-based. Further, it can be applied to a wide range of fields such as sealing agents, adhesives, inks, coating materials, casting materials, elastomers, foam and plastic raw materials, and fiber treatment agents.

Claims (2)

[Claims] 1. A hydrophilic polyisocyanate obtained by introducing 2 to 50% by weight of a nonionic hydrophilic group-containing compound consisting of 5 to 50 ethylene oxide repeating units into a polyisocyanate obtained from an aliphatic and / or alicyclic diisocyanate. In contrast, 0.5 to 2 ionic surfactant
It is obtained by mixing 0% by weight, and has an isocyanate group content of 6 to 25% by weight and a weight average molecular weight of 350 to 100 in a substantially solvent-free state.
00, a viscosity of 50 to 20000 mPa · s (25 ° C.), a self-emulsifying polyisocyanate composition having good water dispersion stability. 2. A hydroxyl value of 1 to 300 m as the component (A)
An aqueous emulsion having gKOH / g and a particle size of 0.03 to 1.0 μm, and the self-emulsifying polyisocyanate composition according to claim 1 as the component (B), the component (A) and the component (B).
The component has an isocyanate group / hydroxyl group equivalent ratio of 0.5 to
A water-based coating composition formulated in a range of 5.0.