JPH11171957A - Production of urethane emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain a urethane emulsion useful for coatings, etc., without causing the coagulation and viscosity rise of the emulsion on a chain extension reaction, even when a water-soluble polyol is used as a raw material, by dispers ing a specific urethane prepolymer in water, and subsequently subjecting the dispersed urethane prepolymer to the chain extension reaction. SOLUTION: This method for producing a urethane emulsion comprises (A) reacting (i) a compound having carboxyl groups and/or sulfonic acid groups and two or more hydroxyl groups with (ii) a compound having two or more isocyanate groups and (iii) a 5-100 wt.% water-soluble compound having two or more hydroxyl groups, dispersing the obtained urethane prepolymer having the residual isocyanate groups in water, and subsequently (B) subjecting the dispersed urethane prepolymer to a chain extension reaction using an aromatic and/or aliphatic compound having two or more amino groups and a mol.wt. of 100-300. The obtained urethane polymer emulsion is useful for adhesives, stickers, coatings and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a urethane emulsion.

[0002]

2. Description of the Related Art Self-dispersing urethane emulsions stabilized by hydrophilic groups such as carboxyl groups and sulfonic acid groups in polymers without using emulsifiers can be used as paints, adhesives, adhesives and coatings. Widely used. A method for producing a urethane emulsion is known, and is disclosed, for example, in JP-A-1-135815. In this production method, an urethane prepolymer synthesized from an excess of a polyisocyanate compound and a polyol compound is put into water, stirred and dispersed,
After preparing the urethane prepolymer emulsion, a chain extender capable of reacting with the remaining isocyanate groups in the urethane prepolymer is charged into the stirred urethane prepolymer emulsion, and stirred and dispersed.
The chain of the urethane prepolymer is extended to a high molecular weight to obtain a urethane emulsion.

However, in the above production method, when a water-soluble polyol is used as a polyol compound as a raw material of the urethane prepolymer, aggregation or viscosity increase occurs during a chain extension reaction, and a urethane emulsion cannot be stably obtained. There was a problem.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stable urethane emulsion without causing aggregation or viscosity increase during a chain extension reaction even when a water-soluble polyol is used as a polyol compound. An object of the present invention is to provide a method for producing a urethane emulsion.

[0005]

According to the method for producing a urethane emulsion of the present invention, a compound (A) having a carboxyl group and / or a sulfonic acid group and having two or more hydroxyl groups, and a compound having two or more isocyanate groups are provided. After dispersing a urethane prepolymer having a residual isocyanate group obtained by reacting the compound (B) and the compound (C) having two or more hydroxyl groups in water, the compound (D) having two or more amino groups is used. A method for producing a urethane emulsion obtained by a chain extension reaction, wherein 5 to 100% by weight of the compound (C) is a water-soluble compound, and the compound (D) is an aromatic compound having a molecular weight of 100 to 300. It is a compound and / or an alicyclic compound.

Hereinafter, the present invention will be described. The urethane prepolymer used in the present invention includes a compound (A) having a carboxyl group and / or a sulfonic acid group and having two or more hydroxyl groups, a compound (B) having two or more isocyanate groups, and two compounds having two hydroxyl groups. It can be obtained by reacting the compound (C) having the above, and has a residual isocyanate group in the molecule.

The compound (A) has a carboxyl group and / or a sulfonic acid group in the molecule and has two or more hydroxyl groups, and a polyhydroxy compound is preferably used. Examples of such a compound (A) include 2,2-dimethylol lactic acid, 2,2-dimethylol propionic acid, 2,2-dimethylol butanoic acid,
2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and the like.

The amount of the carboxyl group and / or sulfonic acid group introduced into the urethane prepolymer by the compound (A) is preferably 5 mmol or more per 100 g of the solid content of the urethane prepolymer. 5mmo
When the ratio is less than 1, not only is it difficult to disperse the urethane prepolymer in water, but also the physical properties such as adhesiveness of the finally obtained urethane emulsion are reduced.

The compound (B) is not particularly limited as long as it has two or more isocyanate groups in the molecule, and is preferably an organic polyisocyanate used for a usual urethane resin. Examples of the organic polyisocyanate include 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate,
2,4-trimethylhexamethylene diisocyanate,
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexyl-
2,4-diisocyanate, methylcyclohexyl 2,
Aliphatic diisocyanates such as 6-diisocyanate, 1,3-bis (isocyanate) methylcyclohexane, tetramethylxylylene diisocyanate, transcyclohexane-1,4-diisocyanate and lysine diisocyanate; 2,4-toluylene diisocyanate, 2,6 -Toluylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,5'-naphthene diisocyanate, tolidine diisocyanate, diphenylmethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate Aromatic diisocyanates such as lysine ester triisocyanate, triphenylmethane triisocyanate, 1,6,1,1- Down de country isocyanate,
Examples include triisocyanates such as 1,8-diisocyanate-4,4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and the like. These may be used alone. More than one species may be used in combination.

The above-mentioned compound (C) is a compound different from (4) having two or more hydroxyl groups in the molecule, and is obtained by selecting the urethane emulsion obtained according to the intended purpose or application. Physical properties such as hardness and adhesiveness of the prepolymer can be arbitrarily designed. Examples of the compound (C) include ethylene glycol, propylene glycol, 1,4-butanediol,
1,6-hexanediol, trimethylolpropane,
Polyether polyols such as pentaerythritol, glycerin, polyethylene glycol and polypropylene glycol are used.

The compound (C) includes dicarboxylic acids such as adipic acid, sebacic acid, itaconic acid, maleic anhydride, phthalic acid and isophthalic acid, and ethylene glycol, triethylene glycol, propylene glycol and tripropylene glycol. Polyester polyols obtained from glycols such as 1,4-butanediol, 1,6-hexanediol and neopentyl glycol; polycaprolactone polyol, tetramethylene ether glycol, polybutadiene polyol,
Polycarbonate polyol, polythioether polyol and the like are used. These may be used alone or in combination of two or more.

The molecular weight of the compound (C) is not particularly limited, but is preferably from 100 to 30,000.

In the present invention, even when the compound (B) and / or the compound (C) is a water-soluble compound, a urethane emulsion can be stably obtained unlike the conventional production method. Therefore, a compound having a low molecular weight of 100 to 1,000 and having high water solubility, which has been conventionally difficult to use as compound (C), can be used in a high compounding ratio. In particular, a compound having a molecular weight of 100 to 500, which has conventionally been difficult to use for compound (C), can also be suitably used. Here, the water-soluble compound means that the solubility in water at 20 ° C. is 50%.
g / 100 g (water) or more.

The method for obtaining the urethane prepolymer by polymerizing the compound (A), the compound (B) and the compound (C) is not particularly limited. For example, bulk polymerization or solution polymerization can be employed. However, solution polymerization is preferred because of easy control of the reaction.

The solvent used in the above solution polymerization includes:
A hydrophilic solvent which is inert to isocyanate groups, can be efficiently removed from the system at the time of solvent removal, and has a boiling point of 100 ° C. or lower is preferable. Examples of such a solvent include acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate and the like.

The temperature of the above polymerization reaction is preferably from 50 to 150 ° C., more preferably from 60 to 90 ° C. 50
When the temperature is lower than 0 ° C, the polymerization reaction rate is reduced, and when the temperature is higher than 150 ° C, gelation easily occurs during the polymerization reaction. In order to promote the polymerization reaction, a tin-based or amine-based catalyst may be used.

The urethane prepolymer obtained by the above polymerization reaction has a residual isocyanate group, and preferably has an equivalent ratio represented by the following formula of 1.1 to 2. Equivalent ratio = [isocyanate equivalent in compound (B)] /
[Active hydrogen equivalent in compounds (A) and (C)]

If the equivalent ratio is less than 1.1, the resulting urethane prepolymer has a high molecular weight, so that its dispersibility in water is reduced. If it is more than 2, the obtained urethane prepolymer has a low molecular weight. I do. In the present invention, a urethane emulsion can be stably obtained even when the water-soluble compound is blended in a high ratio, even in a large equivalent ratio range of 1.75 to 2.

The urethane prepolymer is JIS K
The content of residual isocyanate groups, measured according to 1603, is preferably 2 to 15% by weight, more preferably 2 to 10% by weight. If the content is less than 2% by weight, the viscosity of the urethane prepolymer increases, and the dispersibility in water decreases, making it difficult to obtain a urethane emulsion. On the other hand, if the content exceeds 15% by weight, the chain extension reaction due to the remaining isocyanate groups becomes violent, and aggregation and solidification are liable to occur.

In the present invention, it is possible to improve the properties of the urethane emulsion by adding the modifier to the urethane prepolymer and then dispersing the urethane prepolymer in water. it can. In this case, it is preferable to perform the treatment based on the residual isocyanate groups calculated per solid content of the entire dispersion including the modifier.

Examples of the modifying agent include rosin resins such as gum rosin, tall oil rosin, wood rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin ester, rosin modified phenol; terpene resin, phenol resin, terpene phenol Resin, xylene resin, ketone resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, coumarone resin, tackifier resin such as styrene resin; styrene resin, (meth) acrylic resin, vinyl acetate resin ,
Thermoplastic resin such as epoxy resin, phenoxy resin, vinyl chloride resin, urethane resin, acrylonitrile resin; N
Rubbers such as BR, chloroprene, acrylic rubber and urethane rubber; waxes such as paraffin wax, microcrystalline wax, low molecular weight polyethylene wax and polyethylene oxide wax; hindered phenol-based, hindered amine-based, benzotriazole-based, phosphorus-based, etc. Antioxidants and ultraviolet absorbers; dioctyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, and the like; phthalic acid-based plasticizers; phosphorus-based plasticizers such as trioctyl phosphate and triphenyl phosphate; benzoate-based plasticizers; inorganic fillers; Dyes; pigments and the like.

In the present invention, when the urethane prepolymer is dispersed in water, the carboxyl groups and / or carboxyl groups contained per 100 g of the urethane prepolymer are dispersed.
Alternatively, of the sulfonic acid groups, 5 to 30 mmol is preferably neutralized, more preferably 7 to 20 mmol.

If the neutralization amount is less than 5 mmol, the urethane prepolymer has too low dispersibility to form coarse particles, and if it exceeds 30 mmol, it becomes too fine particles to have high viscosity and has a high solid content concentration. Can not be obtained. Further, after the urethane prepolymer is completely dispersed in water to form particles having an appropriate particle size, the urethane prepolymer may be further neutralized in order to improve the stability of the obtained urethane emulsion.

The neutralization method is not particularly limited, and includes, for example, a method of adding a neutralizing agent to the urethane prepolymer. By adding the neutralizing agent, carboxyl groups and / or
Alternatively, since the sulfonic acid group and the hydrophilic group in the above-mentioned modifier added as necessary are neutralized, ionization in water is facilitated and the dispersion state in water is stabilized. The neutralization may be performed on a part of hydrophilic groups such as a carboxyl group and / or a sulfonic acid group contained in the urethane prepolymer, or may be performed on the whole. Further, the neutralizing agent may be directly added to the urethane prepolymer before being dispersed in water, or may be added to water. The neutralizing agent is not particularly limited, and includes, for example, ammonia, trimethylamine, triethylamine and the like.

The viscosity of the entire dispersion of the urethane prepolymer is preferably 10,000 cP or less, more preferably 5,000 cP or less, and still more preferably 2,000 cP, because the higher the viscosity, the worse the dispersibility in water.
It is as follows. The viscosity was measured using a B-type viscometer.
It is a value measured under the conditions of ° C. and 60 rpm.

In the present invention, a hydrophilic organic solvent may be used for the purpose of obtaining good dispersibility in water. On this occasion,
When the amount of the solvent increases, a large amount of energy is required in the desolvation step, so that the economy is poor. Therefore, the amount of the hydrophilic organic solvent used is preferably 5 to 100% by weight, more preferably 5 to 65% by weight, based on the solid content of the dispersion. In the present invention, since the remaining isocyanate groups in the urethane prepolymer can be produced in the range of 2 to 15% by weight, the molecular weight and the viscosity of the urethane prepolymer are reduced,
The amount of the hydrophilic organic solvent used can be reduced.

The above-mentioned hydrophilic organic solvent is preferably a solvent which is inert to isocyanate groups, has a boiling point of 100 ° C. or lower, and can be efficiently removed from the system when the solvent is removed. , Methyl ethyl ketone, tetrahydrofuran, ethyl acetate, and other hydrophilic organic solvents used in the above solution polymerization. The hydrophilic organic solvent may be used as a mixture in the material to be dispersed, or may be dissolved in water before the material to be dispersed is dispersed in water.

As the hydrophilic organic solvent, a hydrophilic organic solvent having a boiling point of 100 ° C. or more such as methyl isobutyl ketone may be used in order to improve the dispersibility of the urethane prepolymer and the physical properties of the urethane emulsion. Also,
A hydrophobic organic solvent such as toluene and hexane may be used. However, since removal to the outside of the system is difficult, it is preferable to minimize the amount of use.

In the present invention, in order to obtain a urethane emulsion having good drying properties, when the urethane prepolymer is dispersed, the solid content of the dispersion is 35 to 185% by weight of the amount of water to be dispersed. %, More preferably 50 to 170% by weight. If the amount of water is less than 35% by weight, the solid content of the urethane emulsion obtained by the chain elongation reaction after dispersion and the removal of the solvent will be low, so that the dehydration and concentration operation described later is required, which is inferior in economical efficiency. If it exceeds 185% by weight, a large amount of aggregates will be generated at the time of desolvation, making production difficult.

The method of dispersing the urethane prepolymer in water is not particularly limited, and can be performed by a conventionally known method. Specifically, for example, a method of dispersing while adding water to an organic phase containing a urethane prepolymer in a state where a mechanical shearing force is applied by a high-speed disperser such as a homomixer or a disperser, A method of adding an organic phase containing a urethane prepolymer can be employed.

When the urethane prepolymer is dispersed in water, the urethane prepolymer may be dispersed in a batch system, such as a rotor-stator system, a line mill system, a static mixer system, a vibration system, an ultrasonic method, and a high-pressure system. May be performed. While adopting a batch type or a continuous type, two or more types of equipment may be connected. Also, as a dispersing device,
It may have only one dispersion part or two or more dispersion parts for dispersing an object to be dispersed in water.

In the present invention, after dispersing in the urethane prepolymer water, the remaining isocyanate groups in the urethane prepolymer are allowed to react with a chain extender.
Further increase the molecular weight.

As the chain extender, a compound (D) having two or more amino groups capable of reacting with the remaining isocyanate group in the urethane prepolymer is used.
-Bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, 3-aminomethyl-3,5,5-
Trimethylcyclohexylamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, cis-
Alicyclic compounds such as 2,6-dimethylpiperazine, N, N'-bis (3-aminopropyl) piperazine, 4,4'-cyclohexylmethanediamine, 1- (2-aminoethyl) piperazine; 4,4 ' -Diaminodiphenylmethane,
3,3'-dimethyl-4,4'-diaminodiphenylmethane, m-xylylenediamine, o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, 1,5-naphthylenediamine, toluene-2,4-
Aromatic compounds such as diamine, toluene-2,6-diamine and o-tolidine are preferred.

The chain extenders may be used alone or in combination of two or more.

The alicyclic compound and the aromatic compound are described in Chemical Dictionary (Chemical Dictionary Dictionary Editing Committee, Kyoritsu Shuppan), Vol. 8, p. 599, and vol. 4, page 156. Was quoted.

After the chain extender is added to the dispersed aqueous phase in which the urethane prepolymer is dispersed, the chain extender moves into the particles or the surface of the urethane emulsion and partially or wholly dissolves in the water. It is preferable that the prepolymer is drawn to cause a chain extension reaction. Therefore, it is preferable that the chain extender be soluble in water at the time of addition, and that it is water-soluble as a whole, whether used alone or in combination of two or more. If it is not water-soluble, it will not diffuse uniformly into the urethane emulsion, making it difficult to obtain a stable urethane emulsion.

The chain extender preferably has a molecular weight of 100 to 300. When the molecular weight is less than 100, the hydrophilicity becomes too strong, so that it becomes difficult to obtain a stable emulsion by chain extension reaction in water, and when the molecular weight exceeds 300,
Since the hydrophilicity is too low, it is difficult to uniformly diffuse the compound at the time of addition.

As the above chain extender, ethylenediamine,
Diethylenetriamine, triethylenetetramine, 1,
When an aliphatic polyamine compound having two or more amino groups such as 2-propanediamine and 1,6-hexamethylenediamine is used, the urethane emulsion increases the viscosity of the urethane emulsion with the addition of a chain extender, resulting in coarse particles. , A good urethane emulsion cannot be obtained. In addition, a gel-like aggregate is formed, and a stable urethane emulsion cannot be produced. This is because the chain extender has a high water solubility, does not move to the particle surface quickly after the addition, and undergoes a chain extension reaction with the urethane prepolymer dissolved in the aqueous phase.

Further, a polyisocyanate group in the urethane prepolymer such as a polyalkylene glycol compound such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, or polyethylene glycol, or water is used. Although it is possible to use a compound having two or more active hydrogens capable of reacting as a chain extender, the reactivity is lower than that of the compound (D) having two or more amino groups, so that the production efficiency is significantly reduced. I do.

A compound having at least two functional groups containing active hydrogen capable of reacting with the remaining isocyanate groups in the urethane prepolymer, such as the aliphatic polyamine compound and the polyalkylene glycol compound, together with the chain extender. Is possible, but it is preferable to minimize the amount used.

The time for adding the above chain extender may be before dispersion,
Either at the same time as the dispersion or after the dispersion may be used.
However, before the dispersion, the urethane prepolymer has a high molecular weight and the viscosity increases. Therefore, the dispersion is preferably performed, more preferably after the dispersion.

When the above-mentioned chain extender is added, it is preferable to add it after diluting with water or an organic solvent, and the ratio of the chain extender in the obtained diluted solution is preferably 20 to 80% by weight. If the proportion is less than 20% by weight, the efficiency is poor, and 8
If it exceeds 0% by weight, a chain extension reaction occurs locally at the time of addition, and it becomes difficult to obtain a urethane emulsion stably.

When the urethane emulsion obtained as described above contains an organic solvent, it is preferable to further remove the organic solvent by heating and reducing the pressure to remove the solvent. Further, the urethane emulsion may be concentrated by heating and reducing the pressure to remove water by distillation.

The solid content concentration of the urethane emulsion obtained in the present invention is preferably 20 to 70% by weight, more preferably 25 to 65% by weight. When the solid content is less than 20% by weight, the energy and time required for drying are long, so that the economic efficiency is deteriorated. When the solids concentration is more than 70% by weight, the viscosity of the urethane emulsion is remarkably increased and the coating property is deteriorated. Coating becomes difficult. The solid content is a value measured based on the method for measuring the non-volatile content of the test method for vinyl acetate resin emulsion specified in JIS K6828.

The average particle size of the urethane emulsion is as follows:
The median (d50) of the particle size distribution is preferably from 0.1 to 2 μm, and more preferably from 0.1 to 1 μm. Median (d
If 50) is 0.1 μm, the viscosity becomes too high to maintain good coating properties, and if it exceeds 2 μm, the storage stability is poor.

In the present invention, the urethane emulsion may be used, if necessary, with a vinyl acetate, acrylic, epoxy, ethylene-vinyl acetate or the like used for a coating agent, a paint, an adhesive, an adhesive or the like. NBR, rubber emulsions exemplified by chloroprene; rosin-based resins such as gum rosin, tall oil rosin, wood rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin ester, and rosin-modified phenol resin;
Emulsion of tackifying resin such as terpene resin, phenol resin, terpene phenol resin, xylene resin, ketone resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, cumarone resin, styrene resin; carbon black Filler such as aluminum hydroxide; plasticizer;
A pigment; a film thickening aid; a crosslinking agent and the like may be added.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples and comparative examples of the present invention are shown below. In a reactor equipped with a reflux condenser for synthesizing a urethane prepolymer ,
Polypropylene glycol [(PREMI manufactured by Asahi Glass Co., Ltd.
NOL4010 ", OH number: 11.1", "Uniol D2000", manufactured by NOF Corporation, OH value: 57), or "Uniol D400", manufactured by NOF Corporation, OH value: 28
2), 2,2-dimethylolbutanoic acid (manufactured by Mitsubishi Chemical Corporation)
And methyl ethyl ketone, and stirred at 90 ° C. until uniform. Next, after confirming the reflux of the solvent, the amount of 3-isocyanatomethyl-3,5,5,5
-Trimethylcyclohexyl isocyanate ("VESTANAT IPDI" manufactured by Huls) was added and polymerized to synthesize a urethane prepolymer.

(Examples 1 to 8) Triethylamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and methyl ethyl ketone of predetermined amounts shown in Tables 2 and 3 were added to predetermined amounts of urethane prepolymers shown in Tables 2 and 3, and the resulting mixture was homogenized. Was mixed. Then, 23
Under a temperature condition of ° C., the urethane prepolymer solution in methyl ethyl ketone was stirred using a batch type homogenizer, and a predetermined amount of ion-exchanged water was added. Further, an amount corresponding to 93 mol% of the urethane prepolymer,
Metaxylene diamine (Mitsubishi Gas Chemical Company) or 1,3
Stirring was continued for 1 hour while dropping into the reaction solution an aqueous solution of -bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Company) as a chain extender. Next, the solvent was removed and dewatered while stirring at 45 ° C. and under a reduced pressure of 60 mmHg to obtain a urethane emulsion.

(Comparative Examples 1, 3, 5, 7) The procedure of Example 1 was repeated except that a predetermined amount of ethylenediamine (manufactured by Sumitomo Seika) was used as a chain extender as shown in Tables 4 and 5. An attempt was made to prepare a urethane emulsion, but a drop in the chain extender significantly increased the viscosity of the urethane emulsion, and a good urethane emulsion could not be obtained.

(Comparative Examples 2, 4, 6, and 8) Except that a predetermined amount of 1,6-hexamethylenediamine (manufactured by Wako Pure Chemical Industries) shown in Tables 4 and 5 was used as a chain extender, A urethane emulsion was prepared in the same manner as in Example 1.

The following performance evaluations were performed on the urethane emulsions, and the evaluation results are shown in Tables 2 to 5. (1) Particle Size Distribution of Urethane Emulsion After diluting the obtained urethane emulsion with ion-exchanged water, the particle size distribution was measured using a particle size distribution analyzer (HORIBA LA-910, a laser diffraction type particle size distribution analyzer manufactured by Horiba, Ltd.). The distribution was measured and its median (d50) was determined.

(2) Stability of the urethane emulsion The obtained urethane emulsion was subjected to
After standing for a month, the stability was evaluated by visual observation according to the following criteria. ：: No sedimentation aggregates were observed ×: Sedimentation aggregates were observed

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

The method for producing the urethane emulsion of the present invention is as described above. Even when a water-soluble polyol is used as the polyol compound, the urethane emulsion can be stably formed without causing aggregation or viscosity increase in the chain extension reaction. An emulsion can be obtained. In addition, since a water-soluble polyol can be used in a high ratio, urethane emulsions having various performances can be rapidly and stably produced. Further, the urethane emulsion obtained by the present invention has a small particle size of 0.2 to 2 μm, and thus has excellent storage stability.

Claims (1)

[Claims] 1. A compound (A) having a carboxyl group and / or a sulfonic acid group and having two or more hydroxyl groups, a compound (B) having two or more isocyanate groups, and a compound (C) having two or more hydroxyl groups ), A urethane prepolymer having a residual isocyanate group is dispersed in water, and then subjected to a chain extension reaction with a compound (D) having two or more amino groups to produce a urethane emulsion. 5 to 100% by weight of the compound (C) is a water-soluble compound, and the compound (D) has a molecular weight of 100 to 30.
A method for producing a urethane emulsion, which is an aromatic compound and / or an alicyclic compound.