JP2000248044A - Polyisocyanate composition easily dispersible in water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyisocyanate composition easily dispersible in water and an aqueous coating composition by using the same. SOLUTION: This polyisocyanate composition is a composition of a polyisocyanate having the general formula (R is a 1-4C alkyl group; (n) is 3.0-4.9; Z is a di- or polyisocyanate residue) and also is obtained by reacting (a) an aliphatic or alicyclic diisocyanate or an isocyanate prepolymer prepared from it, with (b) a nonionic hydrophilic component having 3.0-4.9 ethylene oxide recurring units, and further mixing (c) an ionic surfactant. The aqueous coating composition consists of (A) a polyisocyanate composition and (B) an aqueous emulsion. Since the composition is easily dispersible, the aqueous coating composition can be formed (A) singly with it or with (B) by mixing with a resin or a rubber emulsion. It can be applied in a wide field such as a coating material, a sealing agent, an adhesive, etc., where the conventional solvent-based polyurethane coating materials are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyisocyanate composition which is easily dispersed in water, and a water-based coating composition of a cold-curable two-part urethane comprising an aqueous emulsion and the above polyisocyanate composition. In detail, the present invention mainly relates to water-based paints for construction, water-based paints for automobiles, adhesives, building materials, water-based paints for home use, other coating agents, sealing agents, inks, casting materials, elastomers, foams, plastic raw materials, and fiber treatment. The present invention relates to a water-based coating composition which can be used for an agent.

[0002]

2. Description of the Related Art In recent years, guidelines on volatile organic compounds have become strict, and regulations have already been implemented in the United States and Germany, and it is expected 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-part urethane coating composition is difficult to disperse in water, easily reacts with water, and has a problem of generating carbon dioxide. Development of a polyisocyanate capable of suppressing a reaction between an isocyanate group and water in a water-dispersed state has been promoted.

[0003] Japanese Patent Publication No. 55-7472, Japanese Unexamined Patent Publication No.
No. 222150 proposes a polyisocyanate in which a nonionic hydrophilic component is introduced into a polyisocyanate as a method for obtaining a polyisocyanate having high emulsifying properties. In JP-A-6-17004, in order to improve the dispersibility of polyisocyanate,
It has been proposed to identify aqueous emulsion dispersions having emulsifying properties. Further, JP-A-7-48429 and JP-A-7-113005 propose a polyisocyanate in which a nonionic hydrophilic component and a lipophilic group have been introduced in order to extend the pot life. JP-A-9-3
No. 28654 proposes a polyisocyanate excellent in pot life by combining a nonionic hydrophilic component and an ionic hydrophilic component.

However, when the conventional polyisocyanate composition shown above is dispersed in water or an aqueous polyol, a relatively strong shear is applied, or the viscosity is reduced by adding an organic solvent to reduce the dispersibility. It needed to be improved.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyisocyanate composition which is easily dispersed in water, and an aqueous coating composition using the same.

[0006]

Means for Solving the Problems The present inventors have found that a polyisocyanate composition having a nonionic hydrophilic component having an ethylene oxide repeating unit of 3.0 to 4.9 can be easily dispersed in water. Completed the invention. That is, the present invention provides:

Embedded image (Wherein R is an alkyl group having 1 to 4 carbon atoms, n is an average of 3.0 to 4.9, and Z is a diisocyanate or polyisocyanate residue). And (b) 1 to 50% by weight of an aliphatic and / or alicyclic diisocyanate or an isocyanate prepolymer obtained therefrom, based on 100% by weight of the polyisocyanate composition. A nonionic hydrophilic component having at least one hydroxyl group and having 3.0 to 4.9 ethylene oxide repeating units, obtained by reacting both components such that the composition has a content of 5 to 50% by weight; Provided is a polyisocyanate composition that can be easily dispersed in water. Also,

The polyisocyanate composition has an isocyanate group content of 3 to 24% by weight in a state of substantially 100% non-volatile content, and a viscosity of substantially 100% non-volatile content.
% To 50,000 mPa. s (25 ° C),
It is also characterized in that the weight average molecular weight is from 350 to 10,000. Further, the present invention is characterized in that (c) an ionic surfactant containing substantially no water is mixed at 0.5 to 20% by weight. And (A) an aqueous emulsion (latex) comprising a resin or rubber having a hydroxyl value of 1 to 300 mgKOH / g.
And the polyisocyanate composition according to any one of (B) to (C), wherein the equivalent ratio of isocyanate group / hydroxyl group is 0.1.
Provided is a water-based coating composition formulated in a range of 5 to 5.0.

Hereinafter, the present invention will be described in detail. [I] Polyisocyanate composition (1) Characteristics of polyisocyanate composition 1) The polyisocyanate composition of the present invention has a general formula (1):

Embedded image (Wherein R is an alkyl group having 1 to 4 carbon atoms, n is an average of 3.0 to 4.9, and Z is a diisocyanate or polyisocyanate residue). And (b) 1 to 50% by weight of an aliphatic and / or alicyclic diisocyanate or an isocyanate prepolymer obtained therefrom, based on 100% by weight of the polyisocyanate composition. A nonionic hydrophilic component having at least one hydroxyl group and comprising 3.0 to 4.9 ethylene oxide repeating units, and obtained by reacting both components such that the composition becomes 5 to 50% by weight; The present invention relates to a polyisocyanate composition that can be easily dispersed in water.

2) The most characteristic feature of the polyisocyanate composition of the present invention is that it can be easily dispersed in water. For that purpose, the nonionic hydrophilic component (b) constituting the polyisocyanate composition is used. Needs to have a small value of the number of ethylene oxide repeating units of 3.0 to 4.9. Here, "disperse easily in water" means dispersing in water or an aqueous emulsion with weak stirring. Weak stirring refers to stirring using a hand mixer or a stick. When the degree of dispersion in water is measured experimentally, for example, 12 g of water and polyisocyanate composition 8
g into a cup with a diameter of about 4 cm and a diameter of 3.5 cm
The stirring conditions under which most of the polyisocyanate composition was dispersed were measured using the three SUS blades, and the degree of dispersion was represented by the stirring conditions. In order for the polyisocyanate composition of the present invention to be "easily dispersed in water", it must be 500 rpm
Most of the polyisocyanate composition needs to be dispersed in water under stirring conditions of m × 5 minutes, preferably 300 rpm × 4 minutes, more preferably 200 rpm × 3 minutes.

[0010] 3) The polyisocyanate composition of the present invention is preferably in a “substantially 100% nonvolatile state”. The term “substantially 100% non-volatile content” as used in the present invention refers to a state in which the polyisocyanate composition does not substantially contain volatile components such as volatile diisocyanate and solvent. For example, a state in which a volatile component is 1% by weight or less in the polyisocyanate composition. Incidentally, as described below, the polyisocyanate composition of the present invention,
When used, an organic solvent or the like may be mixed and used.

(2) Structural Characteristics of Polyisocyanate Composition (i) Isocyanate Group Content The isocyanate group content in the polyisocyanate composition of the present invention is 3 to 2 in a state where the nonvolatile content is substantially 100%.
It is 4% by weight, preferably 6-20% by weight, more preferably 8-18% by weight. If the isocyanate group content is less than 3% by weight, the cross-linking density in the coating composition will be low, and the coating such as a coating film may be weakened.
Further, since the isocyanate group content is determined from the amount of the hydrophilic component introduced and the molecular weight, the upper limit is necessarily 24% by weight.
It is as follows.

(Ii) Viscosity The viscosity of the polyisocyanate composition of the present invention is 50 to 20,000 mPa. s
(25 ° C.), preferably 100 to 12000 mPa.
s, more preferably 200 to 8000 mPa.s. s. 20000 mPa. If it exceeds s, handling may be difficult. Considering the dispersion in water, the lower the viscosity is, the more desirable it is. If it is less than s, the diisocyanate having a low crosslinking ability may be contained in a large amount, which is not preferable.

(Iii) Weight average molecular weight The polyisocyanate composition of the present invention has a weight average molecular weight of 350 to 10,000, preferably 500 to 50.
00, more preferably 700 to 3000. When the required hydrophilic component (b) is introduced, the weight average molecular weight is inevitably 3
50 or more. If it exceeds 10,000, the viscosity of the polyisocyanate composition becomes high, and handling may be difficult.

(3) Each component of the polyisocyanate composition (i) Isocyanate component (a) 1) Diisocyanate The aliphatic and / or alicyclic diisocyanate used in the present invention includes, for example, tetramethylene diisocyanate, pentane Methylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, 1,
4-diisocyanatocyclohexane and the like.
Among them, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate,
It is preferable because it is easily available industrially. Further, hexamethylene diisocyanate is particularly preferable because the viscosity of the resulting polyisocyanate composition is reduced and the dispersibility in water is improved.

2) Isocyanate prepolymer The isocyanate prepolymer obtained from the above aliphatic and / or alicyclic diisocyanate has a structure such as buret, isocyanurate, urethane, uretdione, allophanate in the molecule. . In particular, an isocyanate prepolymer having a biuret structure is characterized by having excellent adhesion of the coating composition, and an isocyanate prepolymer having an isocyanurate structure is preferably characterized by having excellent water dispersion stability. Further, an isocyanate prepolymer having an isocyanurate structure partially containing a urethane structure and / or an allophanate structure is more preferable because it has more excellent water dispersion stability. The “water dispersion stability” in the present invention refers to the degree of stability of a polyisocyanate composition dispersed in water or an aqueous emulsion. Further, "excellent in aqueous dispersion stability" means a state in which the dispersed polyisocyanate composition does not precipitate.

3) Amount of Isocyanate Component (a) The component (a) derived from an aliphatic and / or alicyclic diisocyanate or an isocyanate prepolymer used in the present invention is a polyisocyanate having substantially 100% non-volatile content. It is composed of 50 to 95% by weight, preferably 60 to 90% by weight, more preferably 70 to 85% by weight based on the isocyanate composition. If the content is less than 50% by weight, the components involved in crosslinking are reduced, and the coating film may become brittle. If it exceeds 95% by weight, the ability to disperse in water may decrease because the hydrophilic component decreases.

(Ii) Nonionic hydrophilic component (b) 1) The nonionic hydrophilic component (b) used in the present invention has one or more, preferably one, "hydroxyl group" and is a repeating unit of ethylene oxide. (Chain). Other examples include pluronic-type polyalkylene glycol monoalkyl ethers, among which polyethylene glycol monomethyl ether is particularly preferred. In addition, the hydroxyl group is 1
If the number is less than 1, a hydrophilic component that cannot react with the isocyanate prepolymer is generated, so that the water resistance of a coating such as a coating film may be reduced.

2) The nonionic hydrophilic component used in the present invention has an ethylene oxide repeating unit number of 3.0 to 4.9,
Preferably 3.0 to 4.5, more preferably 4.0 to 4.0.
4.5. If the number of repeating units is less than 3.0, the aqueous dispersion stability may be poor, which is not preferable. If it exceeds 4.9, the ability to easily disperse in water is lowered, and it is difficult to solidify after the pot life of the water-based coating composition, which is not preferable. By using an ethylene oxide repeating unit of 3.0 to 4.9, the polyisocyanate composition can be easily dispersed in water or an aqueous emulsion. The number of ethylene oxide repeating units can be determined by measuring the hydroxyl value of the hydrophilic component (b) and converting it from the calculated molecular weight.

3) Amount of hydrophilic component (b) The amount of the nonionic hydrophilic component (b) in the polyisocyanate composition of the present invention is 5 to 50% by weight, preferably 5 to 50% by weight, based on the polyisocyanate composition. It is composed of 10 to 40% by weight, more preferably 15 to 30% by weight. If it is less than 5% by weight, it may not be possible to disperse it in water, which is not preferable. If it exceeds 50% by weight, the isocyanate group content of the polyisocyanate composition becomes small, and the crosslink density may decrease, which is not preferable.

(4) Production of Polyisocyanate Composition In the present invention, the reaction of the isocyanate prepolymer (a) with the nonionic hydrophilic component (b)
The urethane reaction between the isocyanate group of the isocyanate prepolymer and the hydroxyl group of the nonionic hydrophilic component. In the urethanization reaction, according to ordinary urethanization reaction conditions, for example, usually at 40 to 160 ° C, preferably 50 to 140 ° C, more preferably 60 to 120 ° C,
It is carried out under a normal atmospheric atmosphere or a nitrogen atmosphere. The reaction may be promoted by using a urethanization catalyst, for example, a tin compound such as dibutyltin dilaurate, diethyltin diacetate, dioctyltin dichloride, a zinc compound, an amine compound, or the like. In this case, by mixing a nonionic hydrophilic component (b) composed of 5 or more ethylene oxide repeating units, it is possible to improve the water dispersion stability, reduce the viscosity, and increase the isocyanate group content.

(5) Ionic surfactant (c) (i) The polyisocyanate composition of the present invention may further contain a water-free ionic surfactant (c). 1) By mixing the ionic surfactant (c),
Since the aqueous dispersion stability of the polyisocyanate composition of the present invention is remarkably improved, even the nonionic hydrophilic component (b) having a relatively short ethylene oxide chain used in the present invention sufficiently achieves the aqueous dispersion stability. Can be.

2) Further, when dispersed in water or an aqueous emulsion, the isocyanate groups in the oil droplets of the polyisocyanate composition significantly improve the ability to protect from water and hydroxyl groups. Life can be dramatically improved.

3) As described above, the use of the ionic surfactant (c) in the production of the polyisocyanate composition is very preferable in terms of paint design. When the ionic surfactant (c) is not used, a method of emulsifying the polyisocyanate composition by the emulsifying power of the aqueous emulsion is preferred. The term "substantially free of water" as used in the present invention means that the water contained in the mixed ionic surfactant (c) reacts with the isocyanate group and does not cause foaming, turbidity and an increase in viscosity. Point. The standard is 1% by weight or less based on the ionic surfactant. The term "water dispersion stability" as used herein means that when dispersed in water or an aqueous emulsion, oil droplets composed of the dispersed polyisocyanate composition are stably present in the water or the aqueous emulsion. If the aqueous dispersion stability is low, the dispersed oil droplets precipitate.

(Ii) Types of ionic surfactant (c) The ionic surfactant (c) is anionic, nonionic,
Although it may be either amphoteric, anionic is most preferred in view of its ability to protect the isocyanate group from water and hydroxyl groups. -As the anionic surfactant, carboxylate type, sulfate type, sulfonate type and phosphate type are suitable. Examples thereof include ammonium alkylbenzene sulfonate, sodium alkyl sulfate, sodium alkyl diphenyl ether disulfonate, sodium dialkyl sulfosuccinate, and alkyl phosphate. -As the cationic surfactant, a quaternary ammonium salt, a pyridinium salt, and an imidazolinium salt are suitable. For example, alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate can be mentioned.

(Iii) Mixing amount of ionic surfactant (c) The mixing amount of the ionic surfactant is 0.5 to 20% by weight, preferably 0.7 to 20% by weight, based on the polyisocyanate composition.
-12% by weight, more preferably 1.0-8% by weight. If the amount is less than 0.5% by weight, the effect of water dispersion stability due to mixing of an ionic surfactant may not be exhibited. If it exceeds 20% by weight, components that do not participate in crosslinking may increase too much, which may cause the coating such as a coating film to become brittle. (6) Addition of organic solvent (i) The polyisocyanate composition of the present invention can be used by adding an organic solvent. The polyisocyanate composition to which the organic solvent has been added has an effect that the viscosity is low, so that the handling is easy and the dispersion in water is easy. In this case, it is necessary that the organic solvent does not have a functional group that reacts with the isocyanate group. The organic solvent must be compatible with the polyisocyanate composition of the present invention.

(Ii) Types of Organic Solvents Such organic solvents include, for example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, methoxypropyl acetate,
Ester compounds such as -methoxybutyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methyl propionate, butyl propionate, butyl butyrate, dioctyl adipate, diisopropyl glutarate; diisopropyl ether, dibutyl ether, dioxane; Ether compounds such as diethoxyethane;

2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone 2-heptanone, 4
Ketone compounds such as heptanone, diisobutyl ketone, isophorone, cyclohexanone, methylcyclohexanone; benzene, toluene, xylene, ethylbenzene,
Aromatic compounds such as butylbenzene and p-cymene; polyethylene glycol dialkyl ether compounds such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether and triethylene glycol dimethyl ether; polyethylene glycol dicarboxylate compounds such as diethylene glycol diacetate; Examples include diethylene glycol monoalkyl ether monocarboxylate such as ethyl ether monoacetate and diethylene glycol monobutyl ether acetate.

(Iii) Amount of Organic Solvent The amount of the organic solvent added to the polyisocyanate composition of the present invention is 1 to 50% by weight, preferably 3 to 40% by weight, more preferably 5 to 30% by weight. If the amount is less than 1% by weight, the merit of mixing the organic solvent, that is, the improvement in handling and dispersibility in water may not be observed, 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 may increase, which is not preferable.

[II] Aqueous coating composition (1) The present invention relates to a composition having a hydroxyl value of 1 to 300 m as the component (A).
Provided is an aqueous coating composition obtained by blending an aqueous emulsion of gKOH / g and the above-mentioned polyisocyanate composition as the component (B) in an isocyanate group / hydroxyl group equivalent ratio in the range of 0.5 to 5.0. be able to. The aqueous emulsion (A) and the polyisocyanate composition
The aqueous coating composition mixed with (B) has a feature that it is easily solidified after the pot life is over. Here, the "number of ethylene oxide repeating units" refers to the number average degree of polymerization.

The "pot life" here is
In water-based coating compositions, aqueous emulsions
After mixing (A) and the polyisocyanate composition (B),
It means the time until the physical properties of the applied coating film are reduced. When the isocyanate content in the mixed coating composition is 50% or less, the physical properties of the coated film such as whitening and poor curing of the coated film may be deteriorated. It can be expressed as the time from mixing of the substances until the isocyanate content becomes 50% or less.

(2) Aqueous Emulsion (A) (i) Type of Aqueous Emulsion (A) The aqueous emulsion (A) used in the present invention includes all resins or rubbers expressed as latex and emulsion. For example, vinylidene chloride-based copolymer, vinyl chloride-based copolymer, vinyl acetate-based copolymer, (meth) acryl-based emulsion, fluorine-based copolymer emulsion, styrene / butadiene-based copolymer latex, acrylonitrile / butadiene-based Ethylene unsaturated polymer latex or emulsion such as copolymer, rubber latex, butadiene copolymer, urethane / acrylic emulsion: polyurethane emulsion. Polyurethane emulsions, acrylic emulsions and fluorine copolymer emulsions are particularly preferred.

(Ii) Hydroxyl value The hydroxyl value of the aqueous emulsion (A) used in the present invention is as follows:
1 to 300 mg KOH / g, preferably 5 to 150 mg
KOH / g, more preferably 10 to 100 mg KOH / g
g. If the amount is less than 1 mgKOH / g, the number of crosslinking points in the coating composition decreases, which may cause a decrease in the curing speed or weakening of a coating such as a coating film, which is not preferable. If it exceeds 300 mgKOH / g, on the contrary, since the number of crosslinking points is too large, the coating may be hard and brittle. Incidentally, the hydroxyl value in the present invention is a value with respect to the non-volatile component of the aqueous emulsion.

(Iii) Particle size The particle size of the aqueous emulsion (A) used in the present invention is as follows:
0.01-1.0 μm, preferably 0.02-0.5 μ
m, more preferably 0.05 to 0.2 μm. 0.
If it is less than 01 μm, the viscosity of the aqueous emulsion may increase, which is not preferable. If it exceeds 1.0 μm, the water resistance and gloss of a coating such as a coating film may decrease, which is not preferable.

(Iv) Mixing ratio of aqueous emulsion (A) and polyisocyanate composition (B) In the present invention, the equivalent ratio of isocyanate group / hydroxyl group of (A) aqueous emulsion and (B) polyisocyanate composition is as follows: , 0.5 to 5.0, preferably 0.8 to 3.0, more preferably 1.0 to 2.0. If less than 0.5,
It is not preferable because the number of crosslinking points in the coating composition decreases, which may cause a decrease in the curing speed or weakening of a coating such as a coating film. If it exceeds 5.0, the coating may become brittle, which is not preferable. The water-based coating composition of the present invention includes not only a mixture of an aqueous emulsion and a polyisocyanate composition, but also a state in which the aqueous emulsion composition and the polyisocyanate composition are placed in separate containers and mixed so as to be mixed before painting.

(2) Additives The polyisocyanate composition and the aqueous coating composition of the present invention may contain, if necessary, a pigment, a dispersion stabilizer, a viscosity modifier, a leveling agent, a light stabilizer, an antioxidant, An ultraviolet absorber, an antifoaming agent, a filler, a plasticizer, a lubricant, a curing accelerator, and the like can be added.

(3) Characteristics of polyisocyanate composition and water-based coating composition 1) The polyisocyanate composition of the present invention has a feature that it is easily dispersed in water or an aqueous emulsion. 2) In addition, the aqueous emulsion (A) constituting the aqueous coating composition of the present invention not only can obtain a tough hard coating film by drying at room temperature or under heating, but also after completion of the pot life, Since the coating composition has a characteristic of being easily solidified, the possibility of erroneous application after pot life is reduced even during on-site coating.

3) Further, the polyisocyanate composition using the ionic surfactant (c) suppresses the reaction between isocyanate groups and water in a water-dispersed state. Pot life can be achieved. Accordingly, it can be used as a coating material in which a solvent-based polyurethane coating material has been used conventionally, particularly as a coating material for repainting an architectural exterior, a coating material for automobile repair, or a plastic coating material. Furthermore, 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.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The measuring method and the adjusting method used in the present invention are described below. Isocyanate group content The isocyanate group content was determined by adding 10 ml of toluene to about 2 g of the sample, neutralizing the isocyanate group with an excess of 2N amine (toluene solution), and then performing back titration with 1N hydrochloric acid. Viscosity The viscosity was measured at 25 ° C. using an E-type viscometer (manufactured by Tokimec Co., Ltd.). Weight average molecular weight The weight average molecular weight was determined by using gel permeation chromatography (GPC). In addition, GPC (column: TSKgelSuper100 manufactured by Tosoh Corporation)
0, TSKgelSuper2000, TSKgelS
upper 3000, carrier: THF, detection method: parallax refractometer).

Water Dispersibility The water can be easily dispersed in water by placing 12 g of water and 8 g of the polyisocyanate composition in a polycup having a diameter of 4 cm.
The mixture was stirred with three 5-cm SUS blades at 200 rpm × 3 minutes, or 300 rpm × 4 minutes, or 500 rpm × 5 minutes, and the dispersion state was visually observed. Isocyanate group retention rate The isocyanate group retention rate of the aqueous dispersion was determined by placing 12 g of water and 8 g of the polyisocyanate composition in a polycup having a diameter of 4 cm, and 600 rpm using three SUS blades having a diameter of 3.5 cm.
After stirring for mx 10 minutes, measure the isocyanate content.
The mixture was allowed to stand at 0 ° C. and 65% RH, and the isocyanate content after a predetermined time was measured. (Isocyanate group content after predetermined time) / (Isocyanate group content immediately after stirring) × 100%

Preparation of Water-Based Coating Composition A water-based coating composition is prepared by adding a predetermined amount of a polyisocyanate composition to an aqueous emulsion, and adding 1 part at 600 rpm.
It was made by stirring for 0 minutes. Particle size The particle size is measured using a Microtrac UPA particle size distribution analyzer (Lee
ds + Northrup). Hardness of the coating film The hardness of the coating film was measured using a Koenig hardness meter, glass plate = 180.
Was measured. Pot life The pot life of the water-based coating composition was measured by measuring the isocyanate content of the mixed water-based coating composition, and expressed as the time at which the value became 50% or less immediately after mixing.

[0041]

[Synthesis Example 1 of Aqueous Emulsion] In a 2 liter four-necked flask equipped with a dropping funnel and a mechanical stirrer, 675 g of water and emanol NC (anionic surfactant, 3
5% aqueous solution, manufactured by Kao Corporation) at 80 ° C
And 8 g of ammonium persulfate (2% aqueous solution) was added as an initiator. Next, the following mixture was dropped into the flask over 4 hours, and the temperature was kept at 80 ° C. for 1 hour after completion of the dropping.

25 g of 2-hydroxymethyl methacrylate (3.5 wt%) 10 g of acrylic acid (1.4 wt%) 2 g of acrylamide (0.3 wt%) 27 g of glycidyl methacrylate (3.8 wt%) 353 g of methyl methacrylate (49.0 wt%) Butyl acrylate 293 g (40.7 wt%) Styrene 9 g (1.3 wt%) Water 400 g Ammonium persulfate (2% aqueous solution) 31 g Eleminor JS-2 (Note 1) 38 g Emulgen 920 (Note 2) 9 g (Note 1) Reactive emulsifier, 39% aqueous solution, manufactured by Sanyo Kasei Co., Ltd. (Note 2) Nonionic surfactant, 25% aqueous solution, Kao Corporation The resulting aqueous emulsion is milky white, has a stable non-volatile content of 38%. It was a dispersion and had a particle size of 0.1 μm. Hydroxyl value 15.0 mgKOH / g, acid value 10.8 mgKOH / g, glass transition temperature 15.7 ° C.
Met.

Example 1 Methoxy polyethylene glycol (trade name: MPG, ethylene oxide repeating unit = 4.2 units, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dioctyl sulfosuccinate (trade name: Newcol 291)
M, 70% non-volatile content, and Nippon Emulsifier Co., Ltd.) were mixed at a non-volatile content weight ratio of 3: 1, and water and the solvent were removed by distillation under reduced pressure. Isocyanurate prepolymer having an isocyanurate structure (trade name: Duranate TP)
A-100, manufactured by Asahi Chemical Industry Co., Ltd.) and 25 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed,
The urethanization reaction was performed at 8 ° C. for 8 hours. The obtained polyisocyanate composition was a pale yellow liquid, the isocyanate group content was 15.0%, the weight average molecular weight was 900, and the viscosity was 3000 mPa · s. When the ease of dispersion of this polyisocyanate composition in water was measured, it was 200 rp.
Almost completely dispersed by stirring for mx 3 minutes. 20 aqueous dispersions
The residual ratio of the isocyanate group content when left at 6 ° C. for 6 hours was 75%.

Example 2 Methoxypolyethylene glycol (trade name: MPG, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkyl sulfosuccinate (trade name: TR-70,
A nonvolatile content of 70% and Mitsui Cytic Co., Ltd.) were mixed at a nonvolatile content of 9: 1 by weight, and water and solvent were removed by distillation under reduced pressure. Mix isocyanate prepolymer having urethane-modified isocyanurate structure (Duranate THA-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) with 25 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above, and 9
The urethanization reaction was performed at 0 ° C. for 8 hours. The obtained polyisocyanate composition is a pale yellow liquid, has an isocyanate group content of 12.7%, and a weight average molecular weight of 100.
0 and the viscosity was 3900 mPa · s. When the ease of dispersing this polyisocyanate in water was measured, it was 200 r.
Almost dispersed at pm × 3 minutes. The residual ratio of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was as follows:
70%.

Example 3 Methoxypolyethylene glycol (trade name: MPG, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (trade name: Newcol 291M, manufactured by Nippon Emulsifier Co., Ltd.) were used in a non-volatile weight ratio. The mixture was mixed at a ratio of 9: 1, and water and the solvent were removed by distillation under reduced pressure. A mixture of 100 g of an isocyanate prepolymer having a urethane-modified isocyanurate structure (trade name: Duranate TSA-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 25 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above is mixed at 90 ° C. For 8 hours. The resulting polyisocyanate composition was a pale yellow liquid, having an isocyanate group content of 12.6% and a weight average molecular weight of 9
00, and the viscosity was 900 mPa · s. When the ease of dispersing this polyisocyanate composition in water was measured,
It was almost dispersed at 00 rpm × 3 minutes. 20 of aqueous dispersion
The residual ratio of the isocyanate group content when left at 6 ° C. for 6 hours was 70%.

Example 4 100 g of a urethane-modified isocyanate prepolymer having a nurate structure (Duranate THA-100, manufactured by Asahi Kasei Corporation) and 20 g of methoxypolyethylene glycol (MPG, manufactured by Nippon Emulsifier Co., Ltd.) were mixed. At 90 ° C. for 8 hours. The obtained polyisocyanate composition is a pale yellow liquid and has an isocyanate group content of 8.5%.
Weight average molecular weight is 1200 and viscosity is 6000 mPa · s
Met. When the ease of dispersing this polyisocyanate composition in water was measured, it was almost dispersed at 200 rpm × 3 minutes. When the aqueous dispersion was left at 20 ° C. for 3 hours, the residual ratio of the isocyanate group content was 80%.
The residual ratio of the isocyanate group content when left for a period of time was 0%.

Example 5 Methoxy polyethylene glycol (trade name: MPG, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dioctyl sulfosuccinate (trade name: Newcol 291M, nonvolatile content: 70%, manufactured by Nippon Emulsifier Co., Ltd.) The mixture was mixed at a nonvolatile content of 3: 1 by weight, and water and solvent were removed by distillation under reduced pressure. Isocyanate prepolymer having biuret structure (trade name: Duranate 24)
A-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 40 g of the mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed,
The urethanization reaction was performed at 8 ° C. for 8 hours. The obtained polyisocyanate composition was a pale yellow liquid, the isocyanate group content was 9.4%, the weight average molecular weight was 1200, and the viscosity was 6,500 mPa · s. When the ease of dispersion of this polyisocyanate composition in water was measured, it was 200 rp.
Almost all were dispersed by stirring for mx 3 minutes. Water dispersion at 20 ° C
The residual ratio of the isocyanate group content when left for 3 hours was 75%, but the isocyanate group content when left at 20 ° C. for 6 hours was 0%.

Example 6 A four-necked flask equipped with a stirrer, a thermometer, and a condenser was charged with 1,000 g of hexamethylene diisocyanate and 40 g of methoxypolyethylene glycol (trade name: MPG, manufactured by Nippon Emulsifier Co., Ltd.). The urethanization reaction was performed at 90 ° C. for 2 hours with stirring. Then, at 90 ° C., 0.04 g of tetramethylammonium capryate as an isocyanuration catalyst was added. 4
After a lapse of time, when the conversion to polyisocyanate became 30% by measuring the isocyanate group content and the refractive index of the reaction solution, 0.16 g of phosphoric acid was added to stop the reaction. The increase in the refractive index immediately after the addition of the catalyst poison was 0.012. After the precipitates were removed by filtration, the first 0.3 torr. (155 ° C.), 0.2 Tor. (145 ° C.), unreacted hexamethylene diisocyanate was removed.

The isocyanate prepolymer obtained is
Light yellow, clear liquid, yield 300g, viscosity 800
mPa · s, isocyanate group content is 20.2% by weight
Met. Methoxy polyethylene glycol (trade name:
MPG, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dioctylsulfosuccinate (trade name: Newcol 291M, manufactured by Nippon Emulsifier Co., Ltd.) were mixed at a nonvolatile content of 3: 1 by weight, and water and vacuum distillation were performed. Solvent was removed. 100 g of the above isocyanate prepolymer, 10 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed, and a urethanization reaction was performed at 90 ° C. for 8 hours.

The obtained polyisocyanate composition is a pale yellow liquid and has an isocyanate group content of 16.4.
%, The weight average molecular weight is 900, and the viscosity is 1300 mPa ·
s. When the ease of dispersion of this polyisocyanate composition in water was measured, it was almost dispersed by stirring at 200 rpm × 3 minutes. The residual ratio of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was 70%.

Example 7 Methoxypolyethylene glycol 1 (trade name: MPG, ethylene oxide repeating unit = 4.2 units, manufactured by Nippon Emulsifier Co., Ltd.) and methoxypolyethylene glycol 2 (trade name: MPG-130, ethylene Oxide repeating unit = 9.1 units, manufactured by Nippon Emulsifier Co., Ltd.)
Were mixed at a weight ratio of 87.5: 12.5, and methoxypolyethylene glycol 3 (ethylene oxide repeating unit =
4.8) was obtained. This methoxypolyethylene glycol 3 and sodium dialkylsulfosuccinate (Newcol 291M, manufactured by Nippon Emulsion Co., Ltd.) were mixed at a nonvolatile content of 9: 1 by weight, and water and the solvent were removed by distillation under reduced pressure. Isocyanurate prepolymer having an isocyanurate structure (trade name: Duranate TPA-10)
0, 100 g of Asahi Kasei Kogyo Co., Ltd.) and 25 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed, and urethanization reaction was carried out at 90 ° C. for 8 hours to obtain a polyisocyanate composition.

This polyisocyanate composition was a pale yellow liquid, had an isocyanate group content of 14.2%, a weight average molecular weight of 900 and a viscosity of 1300 mPa · s. When the ease of dispersion of this polyisocyanate composition in water was measured, it was almost dispersed at 200 rpm × 3 minutes. The residual ratio of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was 75%.

(Example 8) Synthesis example 1 of aqueous emulsion
Of the aqueous emulsion obtained in Example 3 and the polyisocyanate composition obtained in Example 3 by an equivalent ratio of isocyanate groups to hydroxyl groups =
The mixture was mixed at 1.5 to obtain an aqueous coating composition. The pot life of this water-based coating composition is 1 at 20 ° C.
At 0 hours, the aqueous coating composition had completely solidified the next day. A coating film having a thickness of 40 μm was formed using this coating composition, and was cured at 20 ° C. and 65% RH for 24 hours to obtain a transparent coating film. When the gel fraction was measured, it was 79%, the Konig hardness was 40, and no whitening of the coating film was observed even when immersed in water at 20 ° C. for 4 hours. Further, the pot life of the aqueous coating composition obtained by mixing the same aqueous emulsion and polyisocyanate at an equivalent ratio of isocyanate group to hydroxyl group = 1.0 was 10 hours at 20 ° C., and was completely solidified after 24 hours.

Comparative Example 1 An isocyanate prepolymer having a urethane-modified isocyanurate structure (trade name: Duranate TSA-100, manufactured by Asahi Kasei Corporation)
Of methoxypolyethylene glycol (trade name: MPG130, ethylene oxide repeating units =
9.1, manufactured by Nippon Emulsifier Co., Ltd.) and a urethanization reaction was carried out at 90 ° C. for 8 hours. The obtained polyisocyanate is a pale yellow liquid, has an isocyanate group content of 14.7%, a weight average molecular weight of 1,000 and a viscosity of 80.
It was 0 mPa · s. When the ease of dispersing this polyisocyanate composition in water is measured, 200 rpm × 3 minutes,
A large amount of undissolved residue was observed with stirring at 300 rpm × 4 minutes, and a small amount of undissolved residue was observed even at 500 rpm × 5 minutes. When the aqueous dispersion was left at 20 ° C. for 4 hours, the residual ratio of the isocyanate group content was 0%.

Comparative Example 2 Methoxypolyethylene glycol (trade name: MPG-130) and sodium dioctyl sulfosuccinate (trade name: Newcol 291M, nonvolatile content 70%, manufactured by Nippon Emulsifier Co., Ltd.) were used in terms of nonvolatile content by weight. The mixture was mixed at a ratio of 9: 1, and water and the solvent were removed by distillation under reduced pressure. 100 g of an isocyanate prepolymer having a urethane-modified isocyanurate structure (trade name: Duranate TSA-100, manufactured by Asahi Kasei Corporation)
And 25 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed, and a urethanization reaction was performed at 90 ° C. for 8 hours. The obtained polyisocyanate is a pale yellow liquid, having an isocyanate group content of 14.9% and a weight average molecular weight of 100.
0 and the viscosity was 1000 mPa · s. When the easiness of dispersion of this polyisocyanate composition in water was measured, it was found to be 20.
A large amount of undissolved residue was observed with stirring at 0 rpm × 3 minutes and 300 rpm × 4 minutes, and a small amount of undissolved residue was observed even at 500 rpm × 5 minutes. The residual ratio of the isocyanate group content when the aqueous dispersion was left at 20 ° C. for 6 hours was 70%.

Comparative Example 3 Synthesis Example 1 of Aqueous Emulsion
Of the aqueous emulsion obtained in Example 1 and the polyisocyanate composition obtained in Comparative Example 1 by an equivalent ratio of isocyanate groups to hydroxyl groups =
The mixture was mixed at 1.5 to obtain an aqueous coating composition. The pot life of this aqueous coating composition is 3 at 20 ° C.
After 24 hours, the viscosity had increased. Using this coating composition, a coating film having a thickness of 40 μm was prepared.
When cured at 0 ° C. and 65% RH for 24 hours, a slightly cloudy coating film was obtained. When the gel fraction was measured, it was 77%, the Konig hardness was 40, and the coating film was whitened when immersed in water at 20 ° C. for 4 hours. Further, the same aqueous emulsion and polyisocyanate composition were prepared by adding an isocyanate group to a hydroxyl group equivalent ratio = 1.0.
Pot life of the aqueous coating composition mixed in 2
It was 3 hours at 0 ° C. and remained liquid after 24 hours.

Comparative Example 4 Synthesis Example 1 of Aqueous Emulsion
Of the aqueous emulsion obtained in Example 2 and the polyisocyanate composition obtained in Comparative Example 2 by an equivalent ratio of isocyanate groups to hydroxyl groups =
The mixture was mixed at 1.5 to obtain an aqueous coating composition. The pot life of this water-based coating composition is 1 at 20 ° C.
At 0 hours, the viscosity increased after 24 hours. A coating film having a thickness of 40 μm is formed using the coating composition,
When cured at 20 ° C. and 65% RH for 24 hours, a transparent coating film was obtained. When the gel fraction was measured, it was 79%, the Konig hardness was 40, and no whitening of the coating film was observed even when immersed in water at 20 ° C. for 4 hours. The pot life of the aqueous coating composition obtained by mixing the same aqueous emulsion and the polyisocyanate composition at an equivalent ratio of isocyanate groups to hydroxyl groups = 1.0 was 10 hours at 20 ° C., and remained liquid after 24 hours. Was.

[0058]

As described above, the polyisocyanate composition of the present invention comprises:
It has the characteristic of being easily dispersed in water or an aqueous emulsion. Further, the water-based coating composition of the present invention,
By mixing and drying the polyisocyanate composition and the aqueous emulsion at room temperature or by heating, not only can a tough hard coating be obtained, but also the water-based coating composition can be easily solidified after the end of the pot life. As a result, the possibility of erroneous application after the pot life is reduced even during on-site coating. Furthermore, a polyisocyanate composition using an ionic surfactant can suppress a reaction between an isocyanate group and water in a water-dispersed state, so that a long pot life can be achieved when an aqueous coating composition is used. . Accordingly, it can be used as a coating material in which a solvent-based polyurethane coating material has been used conventionally, particularly as a coating material for repainting an architectural exterior, a coating material for automobile repair, or a plastic coating material. Furthermore, 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.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 175/04 C09J 175/04 C09K 3/10 C09K 3/10 DF term (Reference) 4H017 AA04 AA31 AB06 AC04 AC16 AC19 AD06 AE03 4J034 DA01 DA05 DB07 DB08 DP18 HA02 HA06 HA07 HA14 HB07 HC01 HC08 JA03 JA13 QA05 QC05 RA07 RA08 RA09 RA10 4J038 DG051 DG101 DG271 DG291 JB23 JC09 JC14 JC24 KA09 MA10 MA14 MA15 EA18 4E031 BC03 EF321 HC18 HD12 HD13 HD24 JA03 KA38 LA01 LA11

Claims (4)

[Claims] [Claim 1] General formula (1): (Wherein R is an alkyl group having 1 to 4 carbon atoms, n is an average of 3.0 to 4.9, and Z is a diisocyanate or polyisocyanate residue). And (b) 1 to 50% by weight of an aliphatic and / or alicyclic diisocyanate or an isocyanate prepolymer obtained therefrom, based on 100% by weight of the polyisocyanate composition. Having two or more hydroxyl groups,
A nonionic hydrophilic component composed of 3.0 to 4.9 ethylene oxide repeating units, obtained by reacting both components such that the composition has a content of 5 to 50% by weight;
A polyisocyanate composition that can be easily dispersed in water. 2. The polyisocyanate composition has an isocyanate group content of 3 to 24% by weight and a viscosity of substantially 100% non-volatile content in a state of substantially 100% non-volatile content.
50 to 20000 mPa. s (25 ° C),
The water-dispersible polyisocyanate composition according to claim 1, wherein the weight average molecular weight is from 350 to 10,000. 3. The polyisocyanate composition according to claim 1, further comprising (c) a ionic surfactant containing substantially no water and containing 0.5 to 20% by weight. object. (A) a hydroxyl value of 1 to 300 mg KOH / g;
An aqueous emulsion (latex) composed of a resin or rubber having the following formula (B) and the polyisocyanate composition according to any one of claims 1 to 3 having an isocyanate group / hydroxyl group equivalent ratio of 0.5 to 5.0. A water-based coating composition characterized by being blended in the range of: