JPH09165407A - Production of water-based urethane compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a water-based urethane compound which can give a coating film excellent in weathering resistance, solvent resistance and adhesion and is useful for coating materials, inks or adhesives by obtaining a urethane prepolymer by using an unsaturated monomer as a solvent, adding a hydroxy organic solvent to this prepolymer, dispersing the mixture in water, chain- extending the repolymer and subjecting the entire mixture to a polymerization reaction. SOLUTION: A polyol is reacted with an organic polyisocyanate in an active- hydrogen-free unsaturated monomer to obtain an unsaturated monomer solution (A) of an isocyanate-terminated urethane prepolymer having a molecular weight of 20,000 or below. Component A is mixed with a hydroxy organic solvent, and the resulting mixture is dispersed in water to obtain an aqueous dispersion of a urethane prepolymer. Component B is chain-extended to obtain an aqueous dispersion of a polyurethane solution. Component C is subjected to a polymerization reaction. Thus, a water-based urethane compound comprising a radical polymer comprising urethane and an unsaturated monomer can be obtained.

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, aqueous urethane resins such as emulsions, colloidal dispersions, and water-soluble urethane resins have been developed mainly by synthesis with acetone, methyl ethyl ketone, n-methylpyrrolidone, an aromatic organic solvent and the like, and after a solvent removal process (Progress in). Organic C
coatings, 9, 281, 1981).

These water-based urethane resins are superior to the conventional oil-based urethane resins in terms of use and handling, but it was necessary to completely remove the solvent which impairs the physical properties of the paint or coating when the water-based urethane resin was used. For this reason, problems such as the time and cost required for the solvent removal process, the reuse of the organic solvent, and the incineration and disposal have newly appeared.

[0004] Urethane resins have properties not found in other resins as described above, but are still insufficient from the point of versatility of applications 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.

[0005]

As described above, in the prior art, the step of removing the solvent is always required in the production of the aqueous urethane resin, and the time and cost required for the step are problematic. At the same time, weather resistance, which is a drawback of urethane resin,
It was not possible to obtain an aqueous urethane compound mainly composed of a urethane resin having improved alkali resistance. For these reasons, there has been a strong demand for water-based urethane compounds that do not require solvent removal in the manufacturing process and overcome the drawbacks of conventional urethane resins in the fields involving paints, inks, and adhesives.

In the present invention, a urethane resin is produced by using an unsaturated monomer and an organic solvent having a hydroxyl group in combination, and it is essentially unnecessary to remove the solvent, which is a drawback of the conventional urethane resin. The objective was to provide an excellent method for producing an aqueous urethane compound.

[0007]

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. The method for producing a urethane compound has been completed.

In order to overcome the problems in the conventional method for producing an aqueous urethane resin, a prepolymerization reaction is carried out by using an unsaturated monomer having no active hydrogen as a synthetic solvent for urethane, and its reactivity is confirmed. 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 complexed with an excellent unsaturated monomer.

That is, the first invention is to obtain an aqueous urethane compound composed of 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) An organic solvent having a hydroxyl group in (A) In addition, the second step c) of dispersing in water to obtain the aqueous dispersion (B) of the urethane prepolymer solution c) The chain extension of (B) and the third step of obtaining the aqueous dispersion (C) of the polyurethane solution d) (C) ) Is polymerized, the method for producing an aqueous urethane compound is characterized by comprising a fourth step.

A 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.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail below. In the production of the aqueous urethane compound, the reaction between the polyol and the organic polyisocyanate in the unsaturated monomer having no active hydrogen in the first step is performed by dissolving the polyol in the unsaturated monomer in advance and then dispersing the poly Isocyanate is preferably added and dropped. 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 preferably performed at 50 to 100 ° C. for 1 to 15 hours in the presence of a catalyst.
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.

Further, as the higher molecular weight polyol, there are polyether polyol, polyester polyol, acrylic polyol, epoxy polyol 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, and dibasic acids include adipic acid, azelaic acid, sebacic acid, isophthalic acid, and terephthalic acid. Can be In addition, polycaprolactone, poly β-methyl-
Lactone-based ring-opening polymer polyols such as δ-valerolactone, polycarbonate diols and the like. 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 and 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, and 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, α-methylstyrene and phenyl methacrylate; vinyltriethoxysilane, γ-methacryloyloxypropyl Silicon-containing unsaturated monomers such as trimethoxysilane; Fluorine-containing unsaturated monomers such as octafluoropentyl (meth) acrylate and perfluorocyclohexyl (meth) acrylate,
Examples thereof include monomers having one unsaturated group such as unsaturated monomers having blocked isocyanate groups, and bifunctional unsaturated monomers such as divinylbenzene and polyethylene glycol di (meth) acrylate. Examples of the unsaturated monomer having no active hydrogen include unsaturated monomers which do not contain a carboxyl group, a hydroxyl group, a methylol group, a silanol group, an amide group, a primary or secondary amino group, among the unsaturated monomers. Examples include a polymer.

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.

Organic polyisocyanates include 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.

The catalyst used for the reaction between isocyanate and hydroxyl group is dibutyltin dilaurate, tin octoate, dibutyltin di (2-ethylhexoate),
Lead 2-ethylhexoate, 2-ethylhexyl titanate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, 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 the organic solvent having a hydroxyl group used in the second step, known ones are desirable. For example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, Ethylene glycol mono-n-hexyl ether,
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono-n-hexyl ether, 2,2,4-trimethylpentanediol-1,3, -monoisobutyrate (Texanol, Eastman Chemical Co., Ltd.) or a mixture thereof.

If desired, an organic solvent having no hydroxyl group can be used in combination. By appropriately selecting from these organic solvents as a film-forming aid suitable for the intended coating material, it becomes possible to essentially omit the solvent removal process associated with the hydration, and the pre-preparation obtained in the first step. Water dispersibility is facilitated by lowering the viscosity of the polymer. The method of adding the organic solvent having a hydroxyl group to the urethane prepolymer solution obtained in the first step is preferably carried out at 50 ° C. or lower, preferably 30 ° C. or lower in order to suppress the reaction between the isocyanate and the hydroxyl group as much as possible. Further, it is necessary to immediately perform the following water dispersion.

As a method for dispersing the urethane prepolymer solution in water, 1) a method of neutralizing with a base using a carboxyl group-containing diol as a diol component, 2) prepolymerization with an alkyl dialkanol amine having a tertiary amino group , Quaternization method, 3) prepolymerization with an alkyl dialkanol amine having a tertiary amino group, neutralization with an acid to form an amine salt, 4) highly water-soluble polyol such as ethylene glycol as a urethane component And the like.

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 composite dispersion obtained by polymerizing the dispersion. A small amount of a surfactant may be used in combination for the purpose of improving the mechanical stability of the body.

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, it is possible to stir with a usual stirrer. 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 for 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 chain-extending polyol 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 added by emulsifying with a surfactant or after dissolving in an unsaturated monomer. . 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, cumylperoxyoctate, t-butylperoxy-. Organic peroxides such as 2-ethylhexanoate, t-butylperoxyacetate, lauryl peroxide, di-t-butylperoxide, 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.

Regarding the method for polymerizing the unsaturated monomer, an aqueous dispersion is added dropwise from the viewpoint of total charging, polymerization heat and polymerization stability.
Alternatively, a method of partially charging the rest may be possible. 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 compound of the present invention thus obtained is used as a water-based paint, ink, vehicle for adhesives, binder resin, and also as a primer because it has excellent adhesion to polyolefin. Can be applied.

[0034]

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 introduction tube, a stirrer and a thermometer was replaced with dry air, and 200 parts of ethyl acrylate and 188 parts of butyl acrylate, number averaged. 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. The obtained resin has an NCO% = 0.5.
%, And the number average molecular weight was 16,800.

The monomer solution of the prepolymer was cooled to 30 ° C., 50 parts of ethylene glycol monomethyl ether was added with stirring, 1.1 parts of triethylamine and 500 parts of distilled water were immediately added to disperse the monomer solution of the urethane prepolymer in water. Got the body 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 had a number average molecular weight of about 33,000. The temperature of the aqueous dispersion was raised to 75 ° C. while introducing nitrogen gas into the flask, and potassium persulfate 7.8 was added.
An acrylic polymerization reaction was performed 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 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 and 40 parts of butyl acrylate, number average. 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. The obtained resin has NCO% = 2.0%,
The number average molecular weight was 4,200.

The monomer solution of the prepolymer was cooled to 30 ° C., 50 parts of ethylene glycol monoisopropyl ether was added thereto with stirring, and triethylamine 29 was added immediately.
Parts and 500 parts of distilled water were added to obtain an aqueous dispersion of a urethane prepolymer monomer solution. While maintaining the temperature at 30 ° C., a solution prepared by dissolving 14.3 parts of isophoronediamine 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 had a number average molecular weight of about 29000. 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. Furthermore,
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. The obtained resin has an NCO% of 0.8% and a number average molecular weight of 9,500.
Met.

The prepolymer monomer solution was cooled to 30 ° C., 50 parts of ethylene glycol monoisopropyl ether was added thereto with stirring, and triethylamine 1 was immediately added.
4.4 parts and 500 parts of distilled water were added to obtain an aqueous dispersion of a urethane prepolymer monomer solution. While maintaining the temperature at 30 ° C, 3.8 parts of adipic acid dihydrazide was added to 5 parts of distilled water.
The solution dissolved in 0 parts 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 4 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 130 parts of ethyl acrylate, 100 parts of butyl acrylate, number average. 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. The obtained resin had an NCO% of 0.8% and a number average molecular weight of 11,000.

After cooling the monomer solution of the prepolymer to 30 ° C., 2-hydroxyethyl methacrylate 10
Parts and 50 parts of isopropyl alcohol were added. Under stirring,
14.4 parts of triethylamine and 500 parts of distilled water were added,
An aqueous dispersion of a urethane prepolymer monomer solution was obtained. 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 inlet 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. The obtained resin is N
The CO% was 2.0% and the number average molecular weight was 4,100.

The monomer solution of the prepolymer was cooled to 30 ° C., 50 parts of isopropyl alcohol was added with stirring, 29 parts of triethylamine and 500 parts of distilled water were immediately added to obtain an aqueous dispersion of the monomer solution of the urethane prepolymer. It was 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 to 30 parts.
The mixture was added dropwise over minutes, and then the reaction was continued for 1 hour. The polyurethane thus obtained had a number average molecular weight of about 28,000. 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. The obtained resin has an NCO% of 0.3% and a number average molecular weight of 24,000.
Met.

The monomer solution of the prepolymer was cooled to 30 ° C., 14.4 parts of triethylamine and 500 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 introduction 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. The obtained resin is NCO
% = 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 introduction 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. The obtained resin has NCO% =
It was 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 the 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 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.

× Peel 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.

[0058]

[Table 1]

[0059]

EFFECT OF THE INVENTION Since the solvent removing step is essentially unnecessary, the manufacturing method is cost effective. In addition, in the production process, since the urethane reaction is performed in the unsaturated monomer, the urethane resin and the unsaturated monomer can be directly chemically bonded, and a resin form different from the blend system is used. Can be given. Urethane resin compounded with such unsaturated monomer is weather resistant, which is a drawback of urethane resin without impairing adhesion to base material, abrasion resistance, solvent resistance and impact resistance, which are advantages of urethane. Since it is possible to improve physical properties such as alkali resistance and heat resistance, this method has made it possible to provide a highly practical method for producing an aqueous urethane compound.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C09J 175/04 JEZ C09J 175/04 JEZ

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 urethane prepolymer having an isocyanate group at the terminal and having a molecular weight of 20,000 or less b) An organic solvent having a hydroxyl group is added to (A) and dispersed in water. Second step of obtaining aqueous dispersion (B) of urethane prepolymer solution c) Chain extension of (B) and third step of obtaining aqueous dispersion (C) of polyurethane solution d) Polymerization of (C) A method for producing an aqueous urethane compound, which comprises four steps. 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.