JPS62270614A - Production of aqueous polyurethane dispersion - Google Patents

Abstract

PURPOSE:To obtain the title dispersion excellent in storage stability, mechanical stability and usability in combination with other materials, by preparing an NCO group-terminated prepolymer by using an active hydrogen-containing compound, an organic polyisocyanate compound and a specific compound. CONSTITUTION:An aqueous polyurethane dispersion is produced by preparing an NCO group-terminated prepolymer by reaction a compound (A) (average MW 300-20,000) having at least two isocyanate groups and active hydrogen atoms in the molecule with an organic polyisocyanate compound (B), dispersing the formed prepolymer in water and chain-extending it with a diamine compound (C) in the water. In preparing said prepolymer, 1-30pts.wt. compound of the formula is reacted with 100pts.wt. solid matter of the substance obtained from (A), (B) and (C). In the formula, R1 is a 1-20C alkyl, X and Y are oxyethylene units or the like and m and n are each the number of repeating units.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention provides an aqueous dispersion of a high molecular weight polyurethane resin that does not contain an emulsifier and is useful for paints, fiber treatments, adhesives, etc. It relates to a manufacturing method, and more specifically, it has excellent storage stability, mechanical stability, and compatibility with other resins, inorganic and organic pigments, and fillers, as well as adhesion to various coated objects. The present invention relates to a method for producing an aqueous polyurethane dispersion having excellent performance.

[Conventional technology and its problems]

Various methods have been proposed for producing a high molecular weight aqueous polyurethane dispersion that does not contain an emulsifier, that is, is self-emulsifying. For example, Special Publication No. 43-9076, Special Publication No. 44
-27904, a compound having a basic tertiary amino group in a polyurethane material that can be neutralized with an acid or can be quaternized.

A method of containing a compound having a carboxylic acid group or a sulfonic acid group capable of forming a salt, forming a salt before or during the addition of water to a polyurethane material, and making the polyurethane material water-soluble or water-dispersible. is publicly known. Polyurethane resins made water-based only by the action of salt-forming groups do not contain emulsifiers and exhibit good water resistance, but since the polyurethane resin itself is anionic or cationic, Chemical resistance, especially acid resistance.

The drawback is that either or both of the alkali resistances are significantly deteriorated. In addition, it is easily affected by various salts such as polyvalent metal salts, and as a result, its compatibility with other resins, organic and inorganic pigments, fillers, etc. is extremely poor, and its fruiting applications are severely limited, which is a major drawback. have.

[Problem that the invention seeks to solve]

In order to improve the drawbacks of the salt-forming aqueous polyurethane dispersions mentioned above, the present inventors have conducted extensive studies on polyurethane aqueous dispersions that do not substantially contain nonionic emulsifiers, and have found that they are stable on storage. Productivity 1: Production of an aqueous polyurethane dispersion having excellent mechanical stability, compatibility with other resins, inorganic and organic pigments, fillers, etc., and excellent adhesion to various coated objects. They discovered a method and completed the present invention.

[Means for solving problems]

To summarize the present invention, the present invention comprises (A) an active hydrogen-containing compound having an active hydrogen atom reactive with at least two isocyanate groups in the molecule and having an average molecular weight of 300 to 20,000, and (B) an organic polymer. A prepolymer having an NCO group at the end is prepared by reacting the prepolymer with an isocyanate compound, and then the prepolymer is dispersed in water, and the chain is further extended in water with a diamino compound (C). If desired, the solvent is removed to obtain a polyurethane resin. In the method for producing an aqueous dispersion, when preparing the prepolymer, (D) general formula 〇〇-(x)m-(Y)nn, [However, R1 in the formula
represents a C1-20 alkyl group, X and Y may be the same or different, an essential oxyethylene unit and any one of the oxyethylene unit, oxypropylene unit, or oxybutylene unit. In the combination, m and n indicate the number of repeating units. and the sum of the molecular weights of the oxyethylene units is 2500 to 2500
and the total weight of the oxyethylene units is 60% by weight or more of the total oxyalkylene. ] A polyurethane aqueous dispersion characterized by reacting a compound represented by (A)m (B)m and (C) at a ratio of 1 to 30 parts with respect to 100 parts of solid content of the polyurethane material obtained from (A)m (B)m and (C). This relates to a manufacturing method.

The aqueous polyurethane dispersion of the present invention prepared by the method described above is an aqueous dispersion of a high molecular weight polyurethane resin that is substantially nonionic and does not contain an emulsifier, and can be obtained from this aqueous dispersion. The coating is water resistant,
Excellent chemical resistance.

Moreover, since it is not affected by polyvalent metal salts, etc., it is extremely compatible with other resins, organic and inorganic pigments, fillers, etc.

The configuration of the present invention will be explained in detail below.

Used in the method of the invention. (A) The active hydrogen-containing compound having at least two isocyanate groups and reactive active hydrogen atoms in the molecule and having an average molecular weight of 300 to 20,000 is generally linear and has an average molecular weight of 300 to 20,000.
20,000, preferably 500 to 4,000.

Such compounds include those containing terminal hydroxyl, carboxyl, amino or mercapto groups, such as polyesters and polyacetals.

Mention may be made of polyhydroxy compounds such as polyethers, polythioethers, polyamides and polyesteramides.

- Polyethers include, for example, polymerization products and copolymerization or graft polymerization products of ethylene oxide, propylene oxide, tetrahydrofuran, and butylene oxide, as well as these and polyhydric alcohols, or mixtures thereof and polyhydric alcohols, amines, and polyamines. and polyethers obtained by polymerization with amino alcohols.

- Examples of polyacetals include compounds that can be produced from hexanediol and formaldehyde.

- As polythioethers, mention may be made in particular of polymerization products of thiodiglycol and of mixtures of thiodiglycol with other glycols or polyhydroxy compounds6 - polyesters, polyesteramides and Polyamides are obtained from polyvalent saturated and unsaturated carboxylic acids, polyvalent saturated and unsaturated alcohols, amino alcohols, diamines, polyamines, and mixtures thereof, with linear condensates being predominant. Mention may be made, for example, of polyterephthalates or polycarbonates.

Other polyhydroxy compounds containing urethane groups or urea groups, as well as natural polyols, including those optionally modified, such as castor oil and carbohydrates, can also be used.

It goes without saying that in the process of the invention, mixtures of various polyhydroxy compounds can be added in order to change the hydrophilicity and hydrophobicity and physical properties of the final product.

As mentioned above, the active hydrogen-containing compound (A) used in the method of the present invention has an average molecular weight of 300 to 20,000°, preferably 500 to 4,000. For this reason, of course 40
A mixture of an active hydrogen-containing compound with a molecular weight of 00 or more and an active hydrogen-containing compound with a low molecular weight of 500 or less to have an average molecular weight in the range of 500 to 4,000 is also a preferred active hydrogen-containing compound of the present invention. It is.

The organic polyisocyanate compound (B) used in the method of the present invention is 1, for example, 1,5-naphthylene diisocyanate, 4,4'-
Isomerism of diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate classes, and in some cases mixtures thereof;
All aromatic and Aliphatic diisocyanates are suitable.

Particularly advantageous are partially blocked polyisocyanates which themselves have the ability to form crosslinked polyurethanes, such as dimers of toluylene diisocyanate, or polyisocyanates partially reacted with phenol, tertiary butanol, phthalimide or caprolactam. There are polyisocyanates.

In the present invention, (A) an active hydrogen compound having at least two active hydrogen atoms reactive with isocyanate groups in the molecule and having an average molecular weight of 300 to 20,000 is used as an excess amount of (B) an organic polyisocyanate compound. According to the method of 40-140℃, preferably 60-120℃
A prepolymer having an NCO terminal group is prepared by reacting with (D) general formula) 10.
(X)-(Y)n R1 [However, R1 in the formula is C1
-/ 20 alkyl groups, X and Y may be the same or different, and a combination of an essential oxyethylene unit and any one of the oxyethylene unit, oxypropylene unit, or oxybutylene unit , m,
n indicates the number of repeating units. The total molecular weight of the oxyethylene units is 2,500 to 15,000, and the total weight of the oxyethylene units is 60% by weight or more of the total oxyalkylene. The compound represented by (A) above.

1 to 100 parts of the solid content of the polyurethane material obtained from component (B) and the chain extender which is component (C) described below.
The point is to react at a ratio of 30 parts.

Next, the compound represented by the general formula (D) HO(X)m (Y)n Rt used in the method of the present invention will be explained.

In the general formula, R1 represents a C2-20 alkyl group, and X and Y may each be the same or different,
an essential oxyethylene unit;
In the combination with either an oxypropylene unit or an oxybutylene unit, m and n indicate the number of repeating units. In the present invention, the total molecular weight of oxyethylene units in the compound represented by the above general formula is 2.
500 to 15,000, and the total weight of the oxyethylene units is 60% by weight or more of the total oxyalkylene.

As a typical compound represented by the above general formula, R1 is 0
It is a compound obtained by adding ethylene oxide alone or ethylene oxide and propylene oxide and/or butylene oxide to a monoalcohol of 1-20, preferably 01-4. At that time, the total molecular weight of the polyoxyethylene moiety, that is, the oxyethylene unit, is 2500 to 15000, preferably 3000 to
1oooo, more preferably 3000 to 8000, and a polyoxyethylene moiety,
In other words, only ethylene oxide, or ethylene oxide and propylene oxide and/or ethylene oxide, or ethylene oxide and propylene oxide and/or It is important to prepare the butylene oxide by block polymerization or random polymerization. The compound (D) thus prepared is a polyoxyalkylene compound in which one terminal group is an alkyl group of 01 to 20 and the other terminal group is a hydroxyl group. The total molecular weight of oxyethylene units is 2
If it is less than 500, the aqueous dispersion of the resulting polyurethane material will be insufficient, and if it exceeds 15,000, the number of hydroxyl groups per unit molecular weight in the hydrophilic monohydroxy compound will be extremely small. Either case is undesirable since the aqueous dispersion effect of the polyurethane material is again significantly reduced.

Furthermore, if the proportion of polyoxyethylene moieties (oxyethylene units) in the polyoxyalkylene moieties (in all oxyalkylene units) in the hydrophilic monohydroxy compound that is the compound (D) is less than 60% by weight, This is not preferred because the degree of hydrophilicity of the hydrophilic monohydroxy compound decreases, that is, the aqueous dispersion ability of the resulting polyurethane material decreases.

In the method of the present invention, the above (D) general formula 〇〇-(X)=
The amount of the hydrophilic monohydroxy compound represented by l (Y)n Rt is the solid content of the polyurethane material obtained from (A)m (B)m and (C) the chain extender described below.
The ratio is 1 to 30 parts to 00 parts. (0) @Amount of aqueous monohydroxy compound is (A) m (B) m and solid content of polyurethane material obtained from (C) described below 10
If the amount is less than 1 part to 0 part, the water dispersibility of the resulting polyurethane material will be poor, and water dispersibility may not be possible, or even if water dispersibility is possible, it will be extremely unstable, which is not preferred. Furthermore, when the amount of the (D) hydrophilic monohydroxy compound is more than 30 parts per 100 parts of the solid content of the polyurethane material, no significant improvement in water dispersibility is observed even if the amount is increased further. This is not preferable because it is not only uneconomical, but also the water resistance and chemical resistance of the resulting film from the aqueous polyurethane dispersion are significantly reduced.

In the method of the present invention, the preferred amount of the hydrophilic monohydroxy compound (D) used is within the range of 2 to 20 parts per 100 parts of solid content of the polyurethane material.

In the method of the present invention, the above-mentioned (A) active hydrogen-containing compound, (D) fi aqueous monohydroxy compound and (B
) When preparing a prepolymer from an organic polyisocyanate compound, the amount of the organic polyisocyanate compound used as a component (B) is the same as that of (A) an active hydrogen-containing compound and (D)
It is used in an equivalent ratio of 1.3 to 2.5, preferably 1.5 to 2.0, based on the amount of the hydrophilic monohydroxy compound used. If the amount (equivalent ratio) of component (B) used is less than 1.3, the prepolymer tends to gel; on the other hand, if it exceeds 2.5, the dispersibility of the final product polyurethane resin in water will decrease. Getting worse.

In the method of the present invention, a low molecular weight polyfunctional hydroxy compound can be used in combination when preparing the prepolymer. Examples of such low molecular weight polyfunctional hydroxy compounds include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, trimethylene glycol, 1,3-butylene gelicol, tetramethylene glycol, hexamethylene glycol, and deca Examples include methylene glycol, neopentyl glycol, octanediol, tricyclodecane dimethylol, and hydrogenated bisphenol A. Of course, you can also use a mixture of two or more of these! 1) Il Also, as mentioned above, since (D) the hydrophilic monohydroxy compound is monofunctional, a small amount of a polyfunctional compound such as a triol such as glycerin or trimethylolpropane, pentaerythritol, or sorbitol may also be used. In such a case, a high molecular weight polyurethane material can be obtained. In addition, in the method of the present invention, it is of course possible to use a compound having a salt-forming group in combination within a range that does not impair the stability of the resulting aqueous polyurethane dispersion, film properties, etc.

Although the prepolymer can be prepared without a solvent, for example, dioxane, acetone, methyl ethyl ketone, or acetate is used to ensure uniform reaction.

NCOs such as nitrile, ethyl acetate, and tetrahydrofuran
An organic solvent that is inert to the group and has a high affinity for water may be used.

After the prepolymer having NCO terminal groups is prepared as described above, the prepolymer is diluted with an organic solvent that is inert to NCO groups and has a high affinity for water, and further diluted with water. An aqueous dispersion of the prepolymer is prepared.

Next, in the present invention, a diamino compound as component (C) is added to this aqueous dispersion to effect chain elongation.

If it is possible to add water to the prepolymer solution to make an aqueous dispersion and then add the diamino compound (C) in a relatively short time, cz can be used as an organic solvent to dilute the prepolymer immediately before water dispersion. '*lower alcohols,
Various ethers such as ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol 7-methyl ether, and propylene glycol monobutyl ether can also be used.

Used in the method of the invention. Suitable diamino compounds as the chain extender (C) are primary or secondary diamino compounds, such as ethylenediamine, propylene diamine, hexamethylene diamine, phenylene diamine, tolylene diamine.

Aliphatic, alicyclic and aromatic diamines such as xylylene diamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, cisophoronediamine, hydrazine, etc. are used alone or in a mixture of two or more. be done.

The amount of the diamino compound (C) used in the prepolymer is 0 per equivalent of the terminal NCO group of the prepolymer.
．． An amount of 7 to 1.1 equivalents is preferred.

If the amount of the diamino compound (C) used is less than 0.7 equivalent with respect to the terminal NCO group of the prepolymer, the storage stability of the resulting aqueous polyurethane dispersion is poor, and the resulting coating film may change color. The strength is low and undesirable.

On the other hand, if the amount is more than 1.1 equivalent, the resulting aqueous polyurethane resin dispersion has poor storage stability and discoloration, which is not preferable.

The amount of water used for dispersing the prepolymer is not particularly limited, but the weight ratio of the prepolymer (excluding organic solvent, if any) is approximately 20 It is generally preferred that the amount be between 40% and 40%.

As a method for dispersing the prepolymer in water, water may be added dropwise to the prepolymer while stirring to effect phase inversion emulsification, or the prepolymer may be added dropwise to water while being thoroughly stirred. In order to minimize the reaction between the isocyanate groups of the prepolymer and water, it is necessary to quickly add water to the prepolymer to disperse it in water, or to apply mechanical shearing force using various homomixers, homogenizers, colloid mills, etc. A method of hydrating while feeding is a preferred water dispersion method. Furthermore, a method using ultrasonic waves in the water dispersion method is also preferred.

The thus obtained aqueous polyurethane dispersion of the present invention can be used as it is, but usually it is azeotropically removed along with water by heating and depressurization in order to remove the various organic solvents used in combination. It is common to adopt a process.

The aqueous polyurethane dispersion of the present invention is an aqueous dispersion of a high molecular weight polyurethane resin that does not substantially contain a nonionic emulsifier. This aqueous dispersion has excellent storage stability, mechanical stability, and compatibility with other resins, inorganic and organic pigments, and fillers, as well as excellent adhesion to various coated materials. have. Therefore, the aqueous polyurethane dispersion of the present invention can be used in many applications to which conventional salt-type aqueous polyurethane dispersions cannot be applied.

Fabrics 2 Paper, leather, wood, metal coating, impregnation of fibers and fabrics (e.g. texture processing, antistatic processing, wrinkle-proof finishing, etc.) Binders, adhesives, pressure-sensitive adhesives, backing agents for fur ( Backing agent) Hydrophobizing agent, as an elasticizing component or anti-fracture component in the construction industry (e.g. additive in concrete mixtures and asphalt mixtures) Vehicles for various paints, external paints, household aerosols It can be used for paints, etc. It can also be used as a binder for coal powder, wood powder, glass fiber, asbestos, paper, plastic or rubber waste, ceramic materials, etc. Furthermore, the aqueous polyurethane dispersion of the present invention can be used as a softening agent in the production of elastic films, foils, and yarns, as an auxiliary agent in textile printing and yarn industries, as an additive for synthetic resin dispersions, and as a sizing agent. It can be used in a wide range of applications, including as a leather finishing agent.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way unless it deviates from the technical idea of the present invention.

<Example 1> First, 1,6 hexanediol-neopentyl glycol-adipic acid-polyester (08 valent 102) was added to a 4-tubular flask equipped with a thermometer, a stirrer, and a reflux condenser.
50 parts and polyoxyethylene monomethyl ether glycol with a molecular weight of 4,060 (molecular formula: 8%) Dehydrated at 130°C, then cooled to 50°C to obtain 536
Add 1 part of methyl ethyl ketone and mix thoroughly.

Next, 250 parts of 4,4'-diphenylmethane diisocyanate was added, heated to 70°C, and reacted at this temperature for 2 hours to obtain a prepolymer solution having terminal NCO groups. After the reaction was completed, it was cooled to 40°C, and then 1000 parts of water was added while stirring at high speed with a homomixer to prepare an aqueous dispersion of the prepolymer. It takes several minutes to drip. Methyl ethyl ketone was removed from the white emulsion thus obtained at 55°C under reduced pressure, and water was added to adjust the concentration, resulting in a non-volatile content of 40.7%, a viscosity of 120 cps, and a pH of 7.
, 1 was obtained. This product formed a transparent, glossy, tough, elastic coating on a glass plate, and the coating had excellent water resistance, acid resistance, and alkali resistance. Also obtained polyurethane aqueous dispersion 1
Add 30 parts of aluminum hydroxide powder as a filler to 00 parts,
The mixture was mixed and stirred using a homomixer, but the mixture was extremely stable. For comparison, when aluminum hydroxide powder was added to a commercially available aqueous anionic polyurethane dispersion, lump-like aggregates were immediately formed.

<Example 2> Add 302 parts of polyoxypropylene glycol with a molecular weight of 605 to the same apparatus as in Example 1, and add 302 parts of polyoxypropylene glycol with a molecular weight of 605 to 120 to 1
After dehydrating at 30°C, cooling to 60°C, and adding 372 parts of methyl ethyl ketone, tolylene diisocyanate (
2,4/2.6 isomer ratio = 80/20) 175 parts were added and held at 80°C for 2 hours. 6 Then HO-(X).

-(Y)n 50 parts of an ethylene oxide-propylene oxide random polymer (polyoxyethylene moiety molecular weight 800G, polyoxyethylene/polyoxyalkylene = 80%) prepared by C4Hs, and 1.
After adding 9 parts of 4-butanediol and reacting at 80°C for 3 hours to obtain a prepolymer solution having terminal NCO groups, the solution was cooled to 40°C, and 20 parts of isopropyl alcohol was added.
0 parts were quickly added and then 60 parts of water were added dropwise over about 5 minutes to obtain a milky white dispersion of the prepolymer. Ethylenediamine 24 was added to the resulting milky white dispersion of the prepolymer.
154 parts of an aqueous solution in which 1 part was dissolved was added dropwise. Then 50℃
Methyl ethyl ketone and isopropyl alcohol were distilled off under reduced pressure to obtain a milky white aqueous polyurethane dispersion with a non-volatile content of 47.3%. This product forms a transparent, glossy, tough, elastic coating on glass plates.

The coating had excellent water resistance, acid resistance, and alkali resistance. Also obtained polyurethane aqueous dispersion 100
20 parts of aluminum hydroxide powder was added as a filler to the mixture, and the mixture was mixed and stirred using a homomixer, but the mixture was extremely stable. For comparison, when aluminum hydroxide powder was added to a commercially available aqueous anionic polyurethane dispersion, lumpy aggregates were immediately formed.

<Example 3> In the same apparatus as in Example 1, two polyoxypolyoxyethylene-polyoxypropylene block polymers with a molecular weight of 1000 (molecular weight of the polyoxyethylene portion 6500, polyoxyethylene/polyoxyalkylene = 75%) were added.
3 parts of the mixture were added, dehydration was performed under reduced pressure at 120°C, and then 200 parts of isophorone diisocyanate was added. React at 100°C for 4 hours, then add 1.0% trimethylolpropane.
1 part and 20.1 parts of dimethylolpropionic acid were added, and the reaction was further carried out at the same temperature for 2 hours, cooled to 60°C, and 40 parts of acetone was added.
0 parts were added to obtain a solution of a prepolymer having terminal -NCO groups.

The obtained prepolymer solution was cooled to room temperature, 130 parts of ethylene glycol monobutyl ether was added all at once and dissolved, and then 800 parts of water was immediately added to make a rough emulsion, which was then passed through a colloid mill to create an aqueous dispersion of the prepolymer. . Next, 1 part of water in which 50 parts of 2-methylpiperazine was dissolved was added.
An aqueous polyurethane dispersion was prepared by adding 45 parts and deacetonizing under reduced pressure.

The resulting aqueous polyurethane dispersion had a nonvolatile content of 48.5
．． It had a viscosity of 180 cps and formed a transparent, glossy, elastic coating film on a glass plate, and the coating had extremely excellent water resistance and chemical resistance. Furthermore, the obtained aqueous polyurethane dispersion exhibited excellent compatibility with both anionic acrylic emulsions and cationic acrylic emulsions. For comparison, a commercially available 7-ionic polyurethane aqueous dispersion was investigated, and although it had good compatibility with anionic acrylic emulsions, it immediately formed lumps with cationic acrylic emulsions. .

<Example 4> In the same apparatus as in Example 1, 483 parts of 1.6 hexanediol-adipic acid-polyester (O) monovalent 116) was added.
38 parts of ethylene oxide-butylene oxide random polymer (molecular weight of polyoxyethylene part: 3100, polyoxyethylene/polyoxyalkylene = 85%) prepared by Ho-(x)m-(y)n-CH3 was added, and the mixture was heated under reduced pressure. Dehydration is carried out at 120°C to 130°C, and then 1
Cool to 00°C, add 210 parts of 1,6 hexamethylene diisocyanate, and react at the same temperature for 3 hours.

Next, it was cooled to 80°C, 400 parts of methyl ethyl ketone was added to make a homogeneous solution, and then 9 parts of trimethylolpropane and 1
, 4-butanediol were added thereto, and the mixture was reacted at the same temperature for 3 hours to obtain a solution of a prepolymer having terminal -NCO groups. The obtained prepolymer solution was cooled to room temperature, 100 parts of isopropyl alcohol was added at once to dissolve it, and then 758 parts of water was added to roughly emulsify it, and then passed through a homomixer to create an aqueous dispersion of the prepolymer. . Next, 150 parts of water in which 95 parts of piperazine hexahydrate was dissolved was added dropwise to prepare an aqueous polyurethane dispersion. The obtained aqueous polyurethane dispersion was subjected to solvent removal under reduced pressure at 55°C to obtain an aqueous polyurethane dispersion having a non-volatile content of 48.6% and a viscosity of 220 cps.

The resulting aqueous polyurethane dispersion formed a transparent, glossy, elastic coating film on a glass plate, and the coating had extremely excellent water resistance and chemical resistance.

<Comparative Example 1> In Example 1, polyoxyethylene monomethyl ether glycol (partial formula HO-(CH,C1,0)n-C
A prepolymer solution having a terminal NCO group was obtained in exactly the same manner except that the molecular weight of H,) was 2030.
After the reaction was completed, it was cooled to 40°C, and then 1000 parts of water was added while stirring at high speed with a homomixer to prepare an aqueous dispersion of the prepolymer. When the mixture was added dropwise over a period of several minutes, white lumps were immediately deposited.

Comparative Example 2> In Example 1, the ethylene oxide-propylene oxide block copolymer represented by HO-(X)-(Y)n CH3 (the molecular weight of the polyoxyethylene part was 31
00. Polyoxyethylene/polyoxyalkylene = 5
A prepolymer solution having terminal NCO groups was obtained in exactly the same manner except that 0%) was used. After the reaction is complete, 200 parts of isopropyl alcohol is immediately added, followed by 60 parts of water.
When 0 part is added dropwise over about 5 minutes, a white coarse dispersion of the prepolymer is obtained.

Ethylenediamine 2 was added to the crude dispersion thus obtained.
When 154 parts of an aqueous solution containing 4 parts of the solution was added dropwise, a white lump was immediately formed.

<Comparative Example 3> In the same apparatus as in Example 1, 1001 parts of adipic acid-1,6 hexanediol-polyester (08 value 56) was dehydrated at 120 to 130°C under reduced pressure, and then tolylene diisocyanate, (2, 4/2.6 isomer ratio = 80/
171.5 parts of 20) were added, and the reaction was carried out at 80°C for 2 hours.

Next, 840 parts of acetone was added for dilution, and then 20.1 parts of dimethylolpropionic acid was added and the reaction was continued at 60°C for 4 hours to form a solution of a prepolymer having terminal NCO groups and carboxyl groups in the side chains. Obtained.

When this solution was poured into 2070 parts of water in which 10 parts of triethylamine and 19.4 parts of piperazine hexahydrate were dissolved,
A milky white aqueous anionic polyurethane dispersion was obtained. This product forms a glossy transparent film on the glass plate, but the alkali resistance of the film is extremely poor, and 3%N
a) When 30 PHR of hexagonal aluminum hydroxide powder, which swelled significantly in a short period of time when the film was immersed in an OH aqueous solution, was added to the polyurethane aqueous dispersion, lump-like aggregates were immediately generated.

〔Effect of the invention〕

As detailed above, the present invention improves storage stability.

mechanical stability, and also other resins, inorganic and organic pigments,
Provided is an aqueous polyurethane dispersion that is highly compatible with fillers and has excellent adhesion to various coated objects. Therefore, the aqueous polyurethane dispersion of the present invention can be used in a wide variety of applications to which conventional salt-type aqueous polyurethane dispersions cannot be applied.

Claims (1)

[Claims] 1. (A) has at least two active hydrogen atoms reactive with isocyanate groups in the molecule, and has an average molecular weight of 300
~20,000 active hydrogen-containing compound and (B) an organic polyisocyanate compound are reacted to prepare a prepolymer having an NCO group at the end, and then the prepolymer is dispersed in water, and further in water, (C) a diamino compound is prepared. In the method for producing an aqueous polyurethane dispersion by chain elongation and optionally removing the solvent, when preparing the prepolymer, (D) general formula HO-(X)_m-(Y)_n
-R_1 [However, R_1 in the formula represents an alkyl group of C_1_ to _2_0, X and Y may be the same or different, and the essential oxyethylene unit and the oxyethylene unit, oxypropylene unit, or oxybutylene In the combination of any one unit, m and n indicate the number of repeating units. The total molecular weight of the oxyethylene units is 2,500 to 15,000, and the total weight of the oxyethylene units is 60% by weight or more of the total oxyalkylene. ], (A), (B
), and polyurethane material solid content obtained from (C) 1
A method for producing an aqueous polyurethane dispersion, characterized in that the reaction is carried out at a ratio of 1 to 30 parts per 100 parts. 2. The method for producing an aqueous polyurethane dispersion according to claim 1, which comprises coexisting an organic solvent that is easily miscible with water when adding water to the polyurethane prepolymer to form an aqueous dispersion. 3. The method for producing an aqueous polyurethane dispersion according to claim 1 or 2, which comprises applying mechanical shearing force when adding water to the polyurethane prepolymer to form an aqueous dispersion. 4. The method for producing an aqueous polyurethane dispersion according to claim 1 or 2, wherein ultrasonic waves are applied when water is added to the polyurethane prepolymer to form an aqueous dispersion.