JPH09143211A - Production of aqueous urethane compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound free from problems of environment, safety and hygiene, having excellent weather resistance, alkali resistance, etc., and useful for coating, etc., absolutely without using organic solvent throughout the steps from the production process to the product by using a composite of a urethane resin and an acrylic resin. SOLUTION: (A) An unsaturated monomer solution of a urethane prepolymer having isocyanate group on the terminal and a molecular weight of <=20,000 is produced by reacting a polyol with an organic polyisocyanate in an unsaturated monomer free from active hydrogen (preferably monomers containing an aromatic monomer). The component A is dispersed in water to obtain (B) an aqueous dispersion of the component A. The obtained component B is subjected to chain extension reaction to obtain (C) an aqueous dispersion of an unsaturated monomer solution of a polyurethane. The objective aqueous urethane compound is produced by the polymerization of the component C. The amount of the urethane prepolymer in the process to produce the component A is preferably 5-60wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aqueous urethane compound comprising a radical polymer of urethane and an unsaturated monomer. The aqueous compound obtained by the present invention gives a coating film having excellent weather resistance, solvent resistance, and adhesion, and is useful in the fields of paints, inks, and adhesives,
It can be used widely.

[0002]

2. Description of the Related Art Urethane resins have excellent adhesiveness to substrates, abrasion resistance, impact resistance, and solvent resistance.
It is widely used in paper, plastics, films, metals, textiles, etc. as inks, adhesives, and various coating agents. Conventionally, it was synthesized and used with an organic solvent as a solvent, but efforts have been made to make it water-based from environmental measures and safety and health for the human body, and emulsions, colloidal dispersions, and water-soluble aqueous urethane resins have been developed. It was These water-based or water-based urethane resins combined with organic solvents are superior to the conventional organic solvent type in terms of use and handling, but the organic solvent is still used in the manufacturing process. Therefore, it is not a fundamental solution for environmental pollution and health and safety. Further, the use of an organic solvent in the production process of these resins involves problems such as the time and cost required for the solvent removal step, the reuse of the organic solvent, and the incineration and discarding.

[0003] Urethane resins have properties not found in other resins as described above, but are still insufficient from the point of versatility of use as paints, inks, and adhesives, for example, weather resistance and alkali resistance. In terms of heat resistance, it is inferior to other resins. As a method for compensating for these drawbacks, a composite with another resin has been attempted. For example, JP-A-60-550
As disclosed in Japanese Unexamined Patent Application Publication No. 64-164, and Japanese Patent Application Laid-Open No. 5-117611, there is a blend of a urethane resin and an acrylic resin. However, in this system, there are problems in stability over time due to blending of both emulsions and physical properties of the film during film formation because both resins are not chemically bonded. JP-A-6-8
No. 0930 discloses emulsion polymerization of acrylic in the presence of an aqueous urethane resin. Although this method is an excellent method for compounding urethane resin and acrylic and can be expected to improve physical properties, an organic solvent is used when an aqueous urethane resin is obtained, and the aqueous resin is obtained by solvent removal as described above. There are various environmental pollution and safety and health problems. As means for solving these problems, for example, Japanese Patent Application Laid-Open
Japanese Patent No. 138211 discloses a method in which polyurethane is synthesized in an acrylic monomer to form a composite. However, this method has drawbacks in that the ratio of urethane resin is lowered and a special stirring device is required because the polyurethane reaction is difficult because the viscosity is remarkably increased in the chain extension reaction.

[0004]

As described above, according to the conventional technique, the resin can be easily manufactured without using any organic solvent in the process of manufacturing the urethane resin, and the urethane resin has the disadvantages of the weather resistance and the weather resistance. It was not possible to obtain an aqueous urethane compound mainly composed of a urethane resin having improved alkalinity. Such water-based urethane compounds are
There has been a strong demand in the fields related to inks and adhesives.

The present invention does not use an organic solvent at all from the manufacturing process to the product by compounding a urethane resin with an acrylic resin, and is excellent in weather resistance and alkali resistance, which are the drawbacks of conventional urethane resins. Another object of the present invention is to provide a method for producing an aqueous urethane compound.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that there are no environmental and health and safety problems, and that they are excellent in weather resistance and alkali resistance. We have completed the manufacturing method of urethane composite resin.

In order to overcome the problems in the conventional method for producing an aqueous urethane resin, an unsaturated monomer having no active hydrogen is used as a synthetic solvent for urethane to perform a prepolymerization reaction, and its reactivity is Analysis revealed that the reaction proceeded in the same way as in an organic solvent.Furthermore, radical polymerization of these unsaturated monomers resulted in the disadvantages of conventional urethane resins such as weather resistance, alkali resistance, and heat resistance. The present invention has led to the discovery of a water-based urethane compound which is excellent in the composition of acrylics.

That is, the first invention is to obtain an aqueous urethane compound comprising a radical polymer of urethane and an unsaturated monomer, in which the step a) is to prepare a polyol in an unsaturated monomer having no active hydrogen. First step of reacting with an organic polyisocyanate to obtain an unsaturated monomer solution (A) of a urethane prepolymer having an isocyanate group at a terminal and having a molecular weight of 20,000 or less b) (A) is dispersed in water to prepare a urethane prepolymer. Second step of obtaining aqueous dispersion (B) of unsaturated monomer solution of polymer c) Third step of chain extension of (B) to obtain aqueous dispersion (C) of unsaturated monomer solution of polyurethane d) A method for producing an aqueous urethane compound, which comprises a fourth step of polymerizing (C).

The second invention is a method for producing an aqueous urethane compound, wherein the urethane prepolymer is contained in the first step in an amount of 5 to 60% by weight. The third invention is
The method for producing an aqueous urethane compound is characterized in that the unsaturated monomer having no active hydrogen comprises a monomer containing an aromatic monomer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the production of an aqueous urethane compound, the reaction between a polyol and an organic polyisocyanate in an unsaturated monomer having no active hydrogen in the first step is
It is preferable to dissolve and disperse the polyol in the unsaturated monomer in advance and then add and drop the polyisocyanate. As a method of dissolving and dispersing the polyol in the unsaturated monomer, an operation of dissolving and dispersing the polyol at room temperature as it is, or an operation of heating and stirring can be used. The heating is preferably performed at a lower temperature to prevent unnecessary polymerization of the unsaturated monomer, or under a purge with dry air and / or in the presence of a trace amount of a polymerization inhibitor. The prepolymerization reaction is carried out in the presence of a catalyst at 50 to 100 ° C. for 1
It is preferably carried out for 15 hours. The end point of the reaction is judged by the NCO% measurement.

The polyol used in the first step preferably has two or more hydroxyl groups in one molecule. For example, low molecular weight polyols include dihydric alcohols such as ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, and glycerin. And trihydric alcohols such as pentaerythritol and sorbitol.

Examples of higher molecular weight polyols include polyether polyols, polyester polyols, acrylic polyols, epoxy polyols and the like. Polyether polyols include polyethylene glycol, polyoxypropylene glycol, poly (ethylene / propylene) glycol, polytetramethylene glycol, polyester polyols include diols, polyesters composed of polycondensates of dibasic acids, and diols include those described above. In addition to ethylene glycol and diethylene glycol,
Dipropylene glycol, 1,4-butanediol,
1,6-hexanediol, neopentyl glycol,
Examples of the dibasic acid include adipic acid, azelaic acid, sebacic acid, isophthalic acid, and terephthalic acid. Other examples include lactone ring-opening polymer polyols such as polycaprolactone and poly β-methyl-δ-valerolactone, and polycarbonate diol. Examples of the acrylic polyol include a copolymer of a monomer having a hydroxyl group. Hydroxyl group-containing monomers include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl acrylate, and dihydroxy acrylate, and epoxy polyols include amine-modified epoxy resins. Other examples include polybutadiene diol and castor oil.

These polyols can be used alone or in combination. In order to balance the adhesion to the object to be coated, the paintability, the physical properties of the coating film, and the like, it is generally necessary to use two or more kinds having different chemical structures in combination or to appropriately select the molecular weight thereof. In addition, it is necessary to select a polyol from the viewpoint of solubility in unsaturated monomers having no active hydrogen and urethanization reaction. For example, when polyester polyol or polyether polyol, which is a highly versatile polyol, is used, the molecular weight is 20,000.
If it is 0 or more, high temperature is required for dissolution, and the urethane reaction becomes difficult due to thickening. Even if the polyol has two or more active hydrogens, it becomes a branched structure, so that the problem of thickening is likely to occur.

When a polyol having an ionizable group such as a carboxyl group or a sulfone group is used as the diol component, a self-emulsifying polyurethane can be obtained. As the carboxyl group-containing polyol, dimethylolpropionic acid, 2,2-dimethylolacetic acid, 2,2-
Dimethylol butyric acid, 2,2-dimethylolpentanoic acid,
Examples include dimethylolalkanoic acid such as dihydroxypropionic acid, dihydroxysuccinic acid, and dihydroxybenzoic acid. Particularly, dimethylolpropionic acid and 2,2-dimethylolbutyric acid are preferred from the viewpoint of reactivity and solubility.

As the unsaturated monomer, unsaturated monomers having a carboxyl group such as (meth) acrylic acid, itaconic acid, crotonic acid; methyl (meth) acrylate, (meth)
Ethyl acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Octyl (meth) acrylate, nonyl methacrylate,
(Meth) acrylic acid alkyl ester such as lauryl (meth) acrylate, methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, hydroxy (Meth) acrylic acid esters having a hydroxyl group such as propyl (meth) acrylate; unsaturated monomers having an epoxy group such as glycidyl (meth) acrylate and allyl glycidyl ether; acrylamide, N-methylol (meth) acrylamide, N An unsaturated monomer having an amide group such as butoxymethyl (meth) acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide; N, N-dimethylaminoethyl methacrylate,
N, N-diethylaminoethyl methacrylate, N, N
-(Meth) acrylic acid having a tertiary amino group such as dimethylaminopropyl methacrylate; nitrogen-containing unsaturated monomers such as N-vinylpyrrolidone, N-vinylimidazole, N-vinylcarbazole; cyclopentyl (meth) acrylate, cyclohexyl Alicyclic (meth) acrylates such as (meth) acrylate and isobornyl (meth) acrylate; aromatic unsaturated monomers such as styrene and α-methylstyrene; vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane and the like. A silicon-containing unsaturated monomer; a fluorine-containing unsaturated monomer such as octafluoropentyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, or an unsaturated group such as an isocyanate group-blocked unsaturated monomer Monomers with one, and divinyl vinyl And bifunctional unsaturated monomers such as polyethylene glycol di (meth) acrylate. As the unsaturated monomer having no active hydrogen,
Among the unsaturated monomers, there may be mentioned unsaturated monomers containing no carboxyl group, hydroxyl group, methylol group, silanol group, amide group, primary or secondary amino group.

In selecting the unsaturated monomer having no active hydrogen, it is desirable to dissolve the polyol and diisocyanate well, but it is also possible to select a system in which the polyol and the diisocyanate are dissolved as the reaction proceeds even if they are not completely dissolved. Is. When the solubility is poor, a monomer having a high solubility in a urethane resin such as vinylpyrrolidone or a monomer relatively soluble in a urethane prepolymer such as an aromatic unsaturated monomer Kinds can also be used.

The organic polyisocyanate includes aromatic, aliphatic and alicyclic diisocyanates. For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, lysine diisocyanate. , Isophorone diisocyanate, trimethylhexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4 '-
Buphenylene diisocyanate, 3,3'-dichloro-
4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate and the like can be used alone or in a mixture.

Examples of the catalyst used for the reaction between the isocyanate and the hydroxyl group include dibutyltin dilaurate, tin octoate, dibutyltin di (2-ethylhexoate),
Lead 2-ethylhexoate, 2-ethylhexyl titanate, iron 2-ethylhexoate, 2-ethylhexoate cobalt, zinc naphthenate, cobalt naphthenate,
Examples include tetra-n-butyltin, stannous chloride, stannic chloride, and iron chloride. The reaction in unsaturated monomers generally has a higher solution viscosity than solvent systems, so it is important to keep the molecular weight of the urethane prepolymer and the ratio of urethane prepolymer and unsaturated monomer within the specified range. Become. When the molecular weight of the urethane prepolymer is 20,000 or more, the viscosity increases remarkably and stirring becomes difficult, so that the reaction takes a long time and the subsequent water dispersion becomes difficult, and aggregates are easily generated. A similar problem occurs even when the ratio of the prepolymer to the total amount of the urethane prepolymer and the amount of unsaturated monomer is 60% or more. Below 5%, the viscosity is low, but the amount of the urethane prepolymer is not sufficient to act as a dispersant. Further, it is difficult to obtain the adhesiveness to the base material, abrasion resistance, solvent resistance, impact resilience, etc. which are characteristics of urethane.

As a method of dispersing the unsaturated monomer solution of the urethane prepolymer in the second step with water, 1) a method of using a carboxyl group-containing diol as a diol component and neutralizing with a base, 2) adding a tertiary amino group A method of prepolymerizing with an alkyl dialkanol amine having and quaternizing,
3) A method of prepolymerizing with an alkyl dialkanol amine having a tertiary amino group, neutralizing with an acid to form an amine salt, 4) a method of using a highly water-soluble polyol, for example, ethylene glycol as a urethane component. . Further, in the present invention, it is preferable not to use a surfactant, but the stability of the aqueous dispersion of the unsaturated monomer solution of the urethane prepolymer, or the machine of the composite dispersion obtained by polymerizing the dispersion. It is also possible to use a small amount of a surfactant together for the purpose of improving the chemical stability.

As the basic compound used for hydration, sodium hydroxide, potassium hydroxide, ammonia,
Methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, ethanolamine, propanolamine, diethanolamine, N
-Methyldiethanolamine, dimethylamine, diethylamine, triethylamine, N, N-dimethylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, morpholine and the like; , Used in mixing. When neutralizing the solution of the unsaturated monomer of the urethane polymer, the compatibility with the solution and the stability after dispersion in water may be different depending on the type of the basic compound, so that it must be appropriately selected. In neutralizing a compound having a carboxyl group such as dimethylolalkanoic acid, the amount is preferably 0.6 to 1.2 equivalents per equivalent of the carboxyl group.

As the surfactant, fatty acid salt, alkyl sulfate ester salt, alkylbenzene sulfonate,
Anionic surfactants such as naphthalene sulfonate and alkyl sulfosuccinate; polyoxyethylene alkyl ether, polyoxyethylene alkyl ester,
There are nonionic surfactants such as polyoxyethylene alkylphenyl ether and polyoxyethylene alkylphenyl ester. It is also possible to use a reactive activator in combination to suppress a decrease in water resistance.

As a method for water-dispersing the unsaturated monomer solution of the urethane prepolymer, stirring with a usual stirrer is also possible. In order to obtain a stable aqueous dispersion, forcible dispersion under a high shearing force using a homomixer, a homogenizer, and a Microfluitizer (manufactured by Mizuho Industry Co., Ltd.) is preferable. In the second step, the solution viscosity after the prepolymerization reaction is lowered to improve the water dispersibility, or a double bond is added to the urethane chain end to form a complex through a chemical bond with another monomer. It is also possible to add monomers having active hydrogen before water dispersion. In water dispersion, the total amount of urethane prepolymer and unsaturated monomer is 70% of the total amount.
% Or less is preferable. If it is more than 70%, aggregates are likely to be formed and it is difficult to obtain a uniform polymer.

A low molecular weight diol or a low molecular weight diamine is used as the chain extension of the NCO-terminated urethane prepolymer in the third step. Trifunctional or higher functional polyols and polyamines also function as crosslinking agents. The chain extension reaction using a diamine is performed at 20 to 80 ° C., preferably 60 ° C. or lower, because the reactivity of amine and isocyanate is high.

Examples of the polyol for chain extension include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, and hydroquinone diethylol ether. Examples of polyamines include aliphatic, alicyclic, aromatic diamines and triamines such as ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, isophoronediamine, piperazine and diphenyldiamine. When these are used, if a monofunctional monoamine or monool is used in combination, the molecular weight can be adjusted by stopping the chain extension reaction.

As a method of adding the chain extender, if it is water-soluble, it can be added as it is, and if it is poorly water-soluble, it can be emulsified with a surfactant or after being dissolved in an unsaturated monomer and then added. . Crosslinkability, water resistance and water repellency can be improved by appropriately selecting the unsaturated monomer even after the completion of the chain extension reaction.

A known radical polymerization method is preferred for polymerizing the aqueous dispersion in the fourth step to obtain a composite dispersion. As the polymerization initiator, both a water-soluble initiator and an oil-soluble initiator can be used. These polymerization initiators are added in an amount of 0.
It is preferably used within the range of 05 to 5%. Temperature is 40 ~
100 ° C. is preferable, and 80 ° C. or lower is sufficient for the redox initiator. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile, benzoyl peroxide, isobutyryl peroxide, octanoyl peroxide, cumyl peroxy octate, t-butyl peroxy-. Organic peroxides such as 2-ethylhexanoate, t-butylperoxyacetate, lauryl peroxide, di-t-butylperoxide, and di-2-ethylhexylperoxyzine carbonate, potassium persulfate, ammonium persulfate,
There are inorganic peroxide compounds such as hydrogen peroxide. Organic or inorganic peroxide compounds can also be used as redox initiators in combination with reducing agents. As the reducing agent used, L-ascorbic acid,
L-sorbic acid, sodium metabisulfite, ferric sulfate, ferric chloride, Rongalit and the like can be mentioned.

With respect to the method of polymerizing the unsaturated monomer, all charging is possible, but from the viewpoint of polymerization heat and polymerization stability, a method of adding an aqueous dispersion dropwise or partially charging the rest is preferred. In the polymerization of the unsaturated monomer, a known chain transfer agent for the purpose of adjusting the molecular weight, for example, octyl mercaptan, lauryl mercaptan, 2-mercaptoethanol, terchardodecyl mercaptan, thioglycolic acid, or the like can be used. is there.

The water-based urethane composite resin of the present invention thus obtained is used as a water-based paint, ink, a vehicle for adhesives, a binder resin, and as a primer because it has excellent adhesion to polyolefin. Can also be applied.

[0029]

The present invention will be described in detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In addition,
In the following examples, “parts” means parts by weight unless otherwise specified.

Example 1 A four-necked 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer and a thermometer was replaced with dry air, and 200 parts of ethyl acrylate and 188 parts of butyl acrylate, number average. Molecular weight about 2,000 (hydroxyl value 5
6.7 parts of polytetramethylene glycol of 6) and 1.4 parts of dimethylolpropionic acid were charged and heated to 60 ° C. 2. Under stirring, diphenylmethane diisocyanate
Add 7 parts and 0.01 parts of dibutyltin dilaurate to 80 ℃
And reacted for 4 hours to obtain a urethane prepolymer monomer solution. As a result of measurement, NCO% was 0.5% and the number average molecular weight was 16,800.

The monomer solution of the prepolymer was cooled to 30 ° C., and with stirring, 1.1 parts of triethylamine and 5 parts of distilled water were added.
50 parts was added to obtain an aqueous dispersion of a urethane prepolymer monomer solution. While maintaining the temperature at 30 ° C., a solution prepared by dissolving 0.2 parts of adipic dihydrazide in 50 parts of distilled water was added dropwise over 30 minutes, and the reaction was continued for 1 hour thereafter.
The polyurethane thus obtained has a number average molecular weight of about 330.
00. While introducing nitrogen gas into the flask, the aqueous dispersion was heated to 75 ° C., 7.8 parts of potassium persulfate was added, and an acrylic polymerization reaction was carried out for 4 hours. Further, 1.9 parts of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Example 2 A four-necked 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer and a thermometer was replaced with dry air, and 40 parts of methyl acrylate and 40 parts of butyl acrylate were used. 158 parts of polypropylene glycol having a molecular weight of about 2,000 (hydroxyl value 56) and 38.2 parts of dimethylolpropionic acid were charged, and the temperature was raised to 60 ° C. Under stirring, diphenylmethane diisocyanate 109.3
And 0.2 part of dibutyltin dilaurate, and the mixture was heated to 80 ° C. and reacted for 4 hours to obtain a urethane prepolymer monomer solution. As a result of measurement, NCO% was 2.0% and the number average molecular weight was 4,200.

The monomer solution of the prepolymer was cooled to 30 ° C. and, with stirring, 29 parts of triethylamine and 55 parts of distilled water.
0 part was added to obtain an aqueous dispersion of a urethane prepolymer monomer solution. While maintaining the temperature at 30 ° C, a solution of 14.3 parts of isophoronediamine dissolved in 50 parts of distilled water was added to 3 parts.
The mixture was added dropwise over 0 minutes, and then the reaction was continued for 1 hour. The polyurethane thus obtained has a number average molecular weight of about 29000.
Met. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and 1.6 parts of potassium persulfate was added to carry out an acrylic polymerization reaction for 4 hours. Further, 0.4 part of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Example 3 A 4-neck 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer and a thermometer was replaced with dry air, and 100 parts of methyl acrylate, 70 parts of butyl acrylate and methyl methacrylate were replaced. 70 parts, 86.4 parts of polypropylene glycol having a number average molecular weight of about 2,000 (hydroxyl value 56) and 19.1 parts of dimethylolpropionic acid were charged and the temperature was raised to 60 ° C. Under stirring, 50.7 parts of diphenylmethane diisocyanate and 0.1 part of dibutyltin dilaurate were added, the temperature was raised to 80 ° C., and the mixture was reacted for 4 hours to obtain a urethane prepolymer monomer solution. As a result of the measurement, NCO% was 0.8% and the number average molecular weight was 9,500.

The monomer solution of the prepolymer was cooled to 30 ° C., 14.4 parts of triethylamine and 550 parts of distilled water were added with stirring to obtain an aqueous dispersion of the monomer solution of the urethane prepolymer. While maintaining the temperature at 30 ° C., a solution prepared by dissolving 3.8 parts of adipic acid dihydrazide in 50 parts of distilled water was added dropwise over 30 minutes, and then the reaction was continued for 1 hour. The polyurethane thus obtained has a number average molecular weight of about 3
2000. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and 4.8 parts of potassium persulfate was added to carry out an acrylic polymerization reaction for 4 hours. Furthermore, 1.2 parts of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Example 4 A four-necked 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer and a thermometer was replaced with dry air, and 130 parts of ethyl acrylate, 100 parts of butyl acrylate, number averaged. Molecular weight about 2,000 (hydroxyl value 5
92.2 parts of polyethylene glycol of 6) and 19.1 parts of dimethylolpropionic acid were charged, and the temperature was raised to 60 ° C. Under stirring, 45.2 parts of isophorone diisocyanate,
0.1 part of dibutyltin dilaurate was added, the temperature was raised to 80 ° C., and the mixture was reacted for 4 hours to obtain a urethane prepolymer monomer solution. As a result of the measurement, NCO% was 0.8% and the number average molecular weight was 11,000.

After cooling the prepolymer monomer solution to 30 ° C., 2-hydroxyethyl methacrylate 10
Parts were added. With stirring, 14.4 parts of triethylamine and 550 parts of distilled water were added to obtain an aqueous dispersion of a monomer solution of urethane prepolymer. Immediately, a solution containing 3.5 parts of adipic acid dihydrazide and 50 parts of distilled water was added dropwise over 30 minutes, and then the reaction was continued for 1 hour. The polyurethane thus obtained had a number average molecular weight of about 32,000. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and 4.8 parts of potassium persulfate was added to carry out an acrylic polymerization reaction for 4 hours. Furthermore, 1.2 parts of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Example 5 A 4-neck 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer and a thermometer was replaced with dry air, and 40 parts of methyl acrylate, 30 parts of butyl acrylate and 10 of styrene were used. Parts, number average molecular weight of about 2,000
(Hydroxyl value 56) polypropylene glycol 158
Parts, 38.2 parts of dimethylolpropionic acid, and 6
The temperature was raised to 0 ° C. Under stirring, 109.3 parts of diphenylmethane diisocyanate and 0.2 of dibutyltin dilaurate were added.
Then, the mixture was heated to 80 ° C. and reacted for 4 hours to obtain a urethane prepolymer monomer solution. Measurement result NCO%
= 2.0% and the number average molecular weight was 4,100.

The monomer solution of the prepolymer was cooled to 30 ° C. and, with stirring, 29 parts of triethylamine and 55 parts of distilled water.
0 part was added to obtain an aqueous dispersion of a urethane prepolymer monomer solution. While maintaining the temperature at 30 ° C., a solution of 14.5 parts of adipic dihydrazide dissolved in 50 parts of distilled water was added dropwise over 30 minutes, and then the reaction was continued for 1 hour.
The polyurethane thus obtained has a number average molecular weight of about 280.
00. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and 1.6 parts of potassium persulfate was added to carry out an acrylic polymerization reaction for 4 hours. Further, 0.4 part of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Comparative Example 1 A 4-neck 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer was replaced with dry air, and 100 parts of methyl acrylate, 70 parts of butyl acrylate, and methyl methacrylate were replaced. 70 parts, 95.4 parts of polytetramethylene glycol having a number average molecular weight of about 2,000 (hydroxyl value 56), dimethylolpropionic acid 19.
One part was charged and heated to 60 ° C. Under stirring, 43.7 parts of isophorone diisocyanate and 0.1 part of dibutyltin dilaurate were added, the temperature was raised to 80 ° C, and the mixture was reacted for 4 hours to obtain a urethane prepolymer monomer solution. As a result of the measurement, NCO% was 0.3% and the number average molecular weight was 24,000.

The monomer solution of the prepolymer was cooled to 30 ° C., 14.4 parts of triethylamine and 550 parts of distilled water were added with stirring to obtain an aqueous dispersion of the monomer solution of the urethane prepolymer. While maintaining the temperature at 30 ° C., a solution of 1.8 parts of adipic dihydrazide in 50 parts of distilled water was added dropwise over 30 minutes, and then the reaction was continued for 1 hour. The polyurethane thus obtained has a number average molecular weight of about 4
It was 1,000. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and 4.8 parts of potassium persulfate was added to carry out an acrylic polymerization reaction for 4 hours. Furthermore, 1.2 parts of potassium persulfate was added and the reaction was continued for 2 hours to obtain an aqueous urethane compound dispersion.

Comparative Example 2 A 4-neck 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer was replaced with dry nitrogen, and 200 parts of methyl ethyl ketone and a number average molecular weight of about 2,000 ( 113 parts of polytetramethylene glycol having a hydroxyl value of 56) and 19.1 parts of dimethylolpropionic acid were charged, and the temperature was raised to 60 ° C. Under stirring, 59.8 parts of diphenylmethane diisocyanate and 0.1 part of dibutyltin dilaurate were added, the temperature was raised to 80 ° C., and the mixture was reacted for 4 hours to obtain a urethane prepolymer. Measurement result NCO% =
It was 1.6% and the number average molecular weight was 5,100.

The prepolymer was cooled to 30 ° C., 14.4 parts of triethylamine and 350 parts of distilled water were added with stirring to obtain an aqueous dispersion of urethane prepolymer. Temperature 3
A solution consisting of 8.2 parts of adipic dihydrazide and 50 parts of distilled water was added dropwise over 30 minutes while maintaining the temperature at 0 ° C. Furthermore, the chain extension reaction was continued for 1 hour to obtain an aqueous urethane compound after desolvation.

Comparative Example 3 A 4-neck 1000 ml flask equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer and a thermometer was replaced with dry nitrogen, and 200 parts of methyl ethyl ketone and a number average molecular weight of about 2,000 ( 113 parts of polypropylene glycol having a hydroxyl value of 56) and 19.1 parts of dimethylolpropionic acid were charged, and the temperature was raised to 60 ° C. Under stirring, 59.8 parts of diphenylmethane diisocyanate and 0.1 part of dibutyltin dilaurate were added, the temperature was raised to 80 ° C., and the mixture was reacted for 4 hours to obtain a urethane prepolymer. Measurement result NCO% = 1.8
% And the number average molecular weight was 5,000.

The prepolymer was cooled to 30 ° C., 14.4 parts of triethylamine and 350 parts of distilled water were added with stirring to obtain an aqueous dispersion of urethane prepolymer. Temperature 3
A solution consisting of 8.2 parts of adipic dihydrazide and 50 parts of distilled water was added dropwise over 30 minutes while maintaining the temperature at 0 ° C. Further, the chain extension reaction was continued for 1 hour, and after removing the solvent, an aqueous urethane resin dispersion was obtained.

Water dispersibility in the second step obtained in Examples and Comparative Examples, degree of aggregates after polymerization of unsaturated monomer in the fourth step, adhesion of water dispersion to PET, weather resistance The sex was evaluated. Each evaluation method is as follows. Table 1 shows the results. a) Water dispersibility Water dispersibility in the second step. ◎ Very good water dispersibility. ○ Good water dispersibility. △ Water dispersibility is slightly poor.

× Water dispersibility is very poor.

B) Formation of Aggregates After polymerization of the unsaturated monomer, the dispersion was filtered to examine the extent of aggregates. ◎ There is no aggregate. ○ Almost no aggregates. △ Aggregates are slightly formed. X: considerable agglomerates are formed.

C) Adhesion to PET The aqueous urethane compound (total solid content: 4) on a PET film.
0%) and the aqueous urethane compound obtained in Comparative Example (solid content 4
(Adjusted to 0%) was applied with a 2.5 mil applicator. After forming the film at 60 ° C., the temperature was returned to room temperature, and the adhesion was examined by a tape peeling test. ◎ Does not peel at all. ○ Almost no peeling. △ Peel a little.

× It peels considerably.

D) Weather resistance The water-based urethane compound (total solid content: 40%) is placed on a slate plate.
%) And the aqueous urethane compound obtained in Comparative Example (solid content: 40%).
%), Left in a weathering tester (Sunshine Weather Meter) for 200 hours, and visually observed the adhesion of the film. ◎ The film does not come off at all. ○ The film hardly peels off. △ The film peeled off a little.

× The film peels off considerably.

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[Table 1]

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The present invention is a production method excellent in environmental pollution and safety and hygiene because essentially no organic solvent is used. Further, in the manufacturing process, since urethane reaction is carried out in an unsaturated monomer, urethane resin and acrylic resin can be directly and chemically bonded to each other, and a resin form different from the blend system can be obtained. it can. In this way, the urethane resin compounded with acrylic is adhesiveness to the base material which is an advantage of urethane, abrasion resistance, solvent resistance, weather resistance, alkali resistance, which are the drawbacks of urethane resin without impairing impact resistance. Since the physical properties such as heat resistance can be improved, it has become possible to provide a highly practical method for producing an aqueous urethane compound by this method.

Claims (3)

[Claims] 1. A process for obtaining an aqueous urethane compound comprising a radical polymer of urethane and an unsaturated monomer, which comprises the steps of: a) reacting a polyol and an organic polyisocyanate in an unsaturated monomer having no active hydrogen. First step of reacting to obtain an unsaturated monomer solution (A) of a urethane prepolymer having an isocyanate group at a terminal and having a molecular weight of 20,000 or less, b) (A) is dispersed in water to unsaturate the urethane prepolymer. Second step of obtaining aqueous dispersion (B) of monomer solution, c) Third step of chain extension of (B) to obtain aqueous dispersion (C) of unsaturated monomer solution of polyurethane, d) A fourth step of polymerizing (C), which is a method for producing an aqueous urethane compound. 2. A method for producing an aqueous urethane compound, wherein the urethane prepolymer in the first step according to claim 1 is 5 to 60% by weight. 3. The method for producing an aqueous urethane compound according to claim 1, wherein the unsaturated monomer having no active hydrogen is a monomer containing an aromatic monomer.