JPH10338732A - Production of water-based urethane composite resin - Google Patents

Abstract

(57) [PROBLEMS] To provide a ketone-based solvent which is useful for paints, inks, adhesives, and coating agents, and is an ordinary urethane synthesis solvent.
Provided is a method for producing a water-based urethane composite resin which does not use an aromatic organic solvent in a prepolymerization reaction and can omit a solvent removing step. A urethane prepolymer is obtained in an unsaturated monomer having no active hydrogen instead of an organic solvent, and a thickening reaction is suppressed by performing a chain extension reaction in the presence of an organic solvent having an active hydrogen. Provided is a method for producing an aqueous urethane composite resin which solves the above-mentioned problem by removing the solvent after polymerization and dispersion of an unsaturated monomer solution of the polyurethane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aqueous urethane composite resin comprising a radical polymer of urethane and an unsaturated monomer. The aqueous composite resin obtained by the present invention provides a coating film having excellent weather resistance, solvent resistance, and adhesion, is useful in the fields of paints, inks, adhesives, and coating agents, and can be widely used. It is possible.

[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, an aqueous urethane resin such as an emulsion, a colloidal dispersion, or a water-soluble type has been developed mainly by using acetone, methyl ethyl ketone, n-methylpyrrolidone, an aromatic organic solvent or the like singly or in a mixture, and through a solvent removal process. (Progressin O
rganic Coatings, 9, 281, 198
1). Aqueous urethane resin is superior to conventional oil-based urethane resin in use and handling, but in its production, the above-mentioned organic solvent is used. New problems such as reuse and incineration have arisen. If the solvent removal is insufficient, there is a possibility that the film formability and the physical properties of the coating film may be impaired. Further, among organic solvents, for example, there is a case where a trace amount of the organic solvent remains a problem in food-related ink and paint applications.

[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 such as stability over time due to blending of both emulsions and phase separation at the time of 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 a urethane resin and an acrylic resin and can be expected to improve physical properties, conventional ketone-based, pyrrolidone-based, and aromatic-based organic solvents are used when synthesizing the urethane resin. Therefore, there are various problems as described above. As means for solving these, for example, JP-A-59-1382
No. 11 discloses a method of synthesizing and synthesizing a polyurethane in an acrylic monomer. However, this method has a drawback that the ratio of the urethane resin is reduced or a special stirrer is required because the viscosity is significantly increased in the chain extension reaction.

[0004]

As described above, in the production of conventional aqueous urethane resins, the use of ketone-based, pyrrolidone-based, aromatic-based or other organic solvents was essential. Therefore, environmental, hygienic, and cost problems due to the use of organic solvents have been serious problems. Further, since the urethane resin made water-soluble in this way is inferior in weather resistance and alkali resistance similarly to the solvent type, it is also necessary to improve their physical properties and increase versatility at the same time. From the current situation, the film formability and coating film properties are impaired in the manufacturing process,
Without the use of conventional urethane synthetic solvents that have environmental problems, and at the same time, the water-resistant urethane resin with improved weather resistance and alkali resistance, which are the drawbacks of urethane resins, can be used in fields involving paints, inks, and adhesives. , Was strongly requested.

According to the present invention, an aqueous urethane composite resin excellent in weather resistance and alkali resistance, which is a drawback of conventional urethane resins, can be prepared without using a conventional ketone-based, pyrrolidone-based or aromatic-based synthetic solvent. Another object of the present invention is to provide a production method which can be easily obtained without increasing the viscosity.

[0006]

Means for Solving the Problems The present inventors have made intensive efforts to solve the above-mentioned problems, and as a result, have no environmental, safety and health problems, and have excellent weather resistance, alkali resistance and the like. The method for producing the aqueous urethane composite resin has been completed.

In order to overcome the problems in the conventional aqueous urethane resin production method, a prepolymerization reaction was carried out using an unsaturated monomer having no active hydrogen as a urethane synthesis solvent, and the reactivity was analyzed. The progress of the reaction was similar to that in the solvent. Further, when the chain extension reaction was subsequently carried out in the presence of a hydroxyl group-containing organic solvent, it was found that thickening could be suppressed and that side reactions hindering the chain extension reaction could be substantially avoided. Finally, radical polymerization of the unsaturated monomers led to the discovery of an aqueous urethane composite resin excellent in weather resistance, alkali resistance, and heat resistance, which are the drawbacks of conventional urethane resins, and combined with acrylics. Was. Since the organic solvent having a hydroxyl group contained in the aqueous urethane composite resin dispersion is widely used for improving film forming properties and coating properties of aqueous inks, adhesives, coating agents, etc., it is completely a solvent. Can be used without removing them.

That is, the first invention is to obtain an aqueous urethane resin composed of a radical polymer of urethane and an unsaturated monomer, comprising: a) a polyol and an organic polyisocyanate in an unsaturated monomer having no active hydrogen; To obtain an unsaturated monomer solution (A) of a urethane prepolymer having an isocyanate group at a terminal and having a number average molecular weight of 20,000 or less. B) (A) the presence of an organic solvent having a hydroxyl group A second step of extending the chain downward to obtain a polyurethane solution (B) c) a radical polymerization of (B) to obtain a polyurethane-polyacrylic solution, and a third step d) dispersing (C) in water to obtain a polyurethane-polyacrylic acid. A fourth step of obtaining an aqueous dispersion (D) of the solution e) a fifth step of removing an organic solvent having a hydroxyl group from (D), comprising: It relates to a method for producing a resin.

The second invention relates to a method for producing an aqueous urethane composite resin, wherein the urethane prepolymer is contained in the first step in an amount of 5 to 60% by weight. The third invention relates to a method for producing an aqueous urethane composite resin, wherein the unsaturated monomer having no active hydrogen in the first step comprises a monomer containing an aromatic monomer. The fourth invention relates to a method for producing an aqueous urethane composite resin, wherein the urethane prepolymer contains polyethylene glycol as an essential component in the first step.

A fifth invention relates to a method for producing an aqueous urethane composite resin, wherein the organic solvent having a hydroxyl group in the second step contains isopropyl alcohol.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the production of an aqueous urethane composite resin, the reaction of a polyol with an organic polyisocyanate in an unsaturated monomer having no active hydrogen in the first step is carried out by previously converting the polyol into an unsaturated monomer. It is preferable to add and drop the polyisocyanate after dissolving and dispersing in water. 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 to 1 hour.
It is preferably performed for 5 hours. The end point of the reaction is NC by titration.
Determined by O% 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, and neopentyl glycol;
And trihydric alcohols such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, and sorivitol.

[0013] 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. In addition, there are 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 a polyester polyol or polyether polyol which is a versatile polyol is used, the molecular weight is 20,000.
If it is 0 or more, a high temperature is required for dissolution, or urethanization 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 polyethylene glycol is used alone or in combination with other diols, the diol can be easily made water-soluble, and a stable dispersion or hydrosol can be obtained.

When a polyol having an ionizable group such as a carboxyl group or a sulfone group is used as the diol component, a self-emulsifiable polyurethane can be obtained. As the carboxyl group-containing polyol, dimethylol propionic acid, 2,2-dimethylol acetic 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.

Examples of the unsaturated monomer having no active hydrogen include unsaturated monomers containing no carboxyl group, hydroxyl group, methylol group, silanol group, primary or secondary amino group and the like. Examples include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and (meth) Hexyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl methacrylate, lauryl (meth) acrylate, methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, (meth) acrylate (Meth) such as ethoxybutyl acrylate
Alkyl acrylate; unsaturated monomer having an epoxy group such as glycidyl (meth) acrylate, allyl glycidyl ether; acrylamide, N-butoxymethyl (meth) acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N An unsaturated monomer having an amide group such as isopropylacrylamide;
N, N-dimethylaminoethyl methacrylate, N, N
(Meth) acrylic acid having a tertiary amino group such as -diethylaminoethyl methacrylate, N, N-dimethylaminopropyl methacrylate; N-vinylpyrrolidone, N
Nitrogen-containing unsaturated monomers such as -vinylimidazole and N-vinylcarbazole; alicyclic (meth) acrylates such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; styrene, α-methylstyrene, Aromatic unsaturated monomers such as phenyl methacrylate; silicon-containing unsaturated monomers such as vinyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane; octafluoropentyl (meth) acrylate, perfluorocyclohexyl (meth) Fluorine-containing unsaturated monomers such as acrylates, monomers having one unsaturated group such as unsaturated monomers blocking isocyanate groups, and bifunctional such as divinylbenzene and polyethylene glycol di (meth) acrylate Unsaturated monomer and the like Can be

By using an unsaturated monomer having no active hydrogen, a urethane resin as designed can be obtained without participating in the reaction between the polyol and the polyisocyanate. In selecting an unsaturated monomer having no active hydrogen, it is desirable to dissolve the polyol and the polyisocyanate well. However, it is also possible to select a system that does not completely dissolve as the reaction proceeds. If solubility is poor, N
-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 may 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'-biphenylenediisocyanate, 1,5-naphthalenediisocyanate, 1,5-tetrahydronaphthalenediisocyanate, and the like can be used alone or in a mixture.

The catalyst used for the reaction between the isocyanate and the hydroxyl group includes dibutyl tin dilaurate, tin octoate, dibutyl tin di (2-ethylhexoate),
Lead 2-ethylhexoate, 2-ethylhexyl titanate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, zinc naphthenate, cobalt naphthenate, tetra-n-butyltin, stannous chloride, Stannic chloride,
Iron chloride.

In the reaction in an unsaturated monomer, the solution viscosity is generally higher than that in a solvent system, so that the molecular weight of the urethane prepolymer and the ratio of the urethane prepolymer to the unsaturated monomer fall within specific ranges. It becomes important. When the number average molecular weight of the urethane prepolymer is 20,000 or more, the viscosity increases significantly, and the reaction takes a long time. Further, even when the ratio of the prepolymer to the total amount of the urethane prepolymer and the unsaturated monomer is 60% by weight or more, the same problem occurs. If the content is 5% by weight or less, it is difficult to obtain the characteristics of urethane such as adhesion to a substrate, abrasion resistance, solvent resistance, and rebound resilience.

As the chain extender for the NCO-terminated urethane prepolymer used in the second step, there is a low molecular weight polyol or a low molecular weight polyamine. When a polyamine is used, a urea bond is introduced into the resin to obtain a polyurethane-urea resin. Trifunctional or higher functional polyols and polyamines also function as crosslinking agents. A chain extension reaction using a polyamine has a high reactivity between amine and isocyanate.
The temperature is preferably 0 to 80C, preferably 50C or lower.

Examples of the polyol for chain extension include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, and hydroquinone diethyl ether. Examples of the polyamine include aliphatic, alicyclic and aromatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, isophoronediamine, piperazine and diphenyldiamine, and triamine. In these uses, if a monofunctional monoamine or monool is used in combination, the molecular weight can be adjusted by terminating the chain extension reaction. Crosslinkability, water resistance and water repellency can be improved by appropriately selecting the unsaturated monomer even after the completion of the chain extension reaction.

As the organic solvent having a hydroxyl group used in the second step, known organic solvents can be used. 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. By using such an organic solvent having a hydroxyl group, an increase in viscosity in a chain extension reaction can be suppressed.
The use of the organic solvent having a hydroxyl group not only suppresses the viscosity increase accompanying the chain extension reaction, but also facilitates the water dispersion in the subsequent step. Among these organic solvents, an organic solvent containing isopropyl alcohol is desirable from the viewpoint of thickening, suppression of side reactions, or functions as a film-forming and coating aid. In the second step, an organic solvent having no hydroxyl group can be used in combination, if necessary.

The method of adding an organic solvent having a hydroxyl group to the urethane prepolymer solution obtained in the first step is carried out at a temperature of 60 ° C. or less, preferably 50 ° C. or less in order to minimize the reaction between the isocyanate and the hydroxyl group. good. The timing of addition is preferably before or during chain extension. In the former, it is necessary to perform chain extension immediately. In the second step, an unsaturated monomer having an active hydrogen, for example, an unsaturated monomer having a carboxyl group such as (meth) acrylic acid, itaconic acid and crotonic acid; 2-hydroxyethyl (meth)
(Meth) acrylic esters having a hydroxyl group such as acrylate, hydroxypropyl (meth) acrylate and 4-hydroxybutyl acrylate; N-methylol (meth) acrylamide and the like can be added before or during chain extension. It is. As a result, the solution viscosity can be further reduced, or a part of the solution reacts with the NCO terminal of urethane, and a complex can be formed through a chemical bond with a polymer of unsaturated monomers in a later step.

In the third step, the unsaturated monomer is polymerized,
A known radical polymerization method is preferable for obtaining a dispersion composed of a polymer of polyurethane and an unsaturated monomer. As the polymerization initiator, both a water-soluble initiator and an oil-soluble initiator can be used. When using the oil-soluble initiator, it is preferable to dissolve it in the organic solvent solution (B) having an unsaturated monomer of polyurethane and a hydroxyl group in advance. These polymerization initiators are suitably used in the range of 0.05 to 5% with respect to the unsaturated monomer. The temperature is preferably from 40 to 100C, and 80C or less is sufficient for a 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
-Butylperoxy-2-ethylhexanoate, t-
Organic peroxides such as butylperoxyacetate, lauryl peroxide, di-tert-butyl peroxide, di-2-ethylhexylperoxyzine carbonate,
There are inorganic peroxide compounds such as potassium persulfate, ammonium persulfate and hydrogen peroxide. Organic or inorganic peroxide compounds can also be used as redox initiators in combination with reducing agents. Examples of the reducing agent to be used include L-ascorbic acid, L-sorbic acid, sodium metabisulfite, ferric sulfate, ferric chloride, Rongalit and the like.

With regard to the method of polymerizing the unsaturated monomer, a method in which the entire amount of the unsaturated monomer of the polyurethane and the organic solvent solution (B) having a hydroxyl group (B) is charged, the entire amount is dropped, or the remaining portion is dropped by charging partly is possible. is there. 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 method of dispersing a solution comprising a polymer of polyurethane and an unsaturated monomer in water in the fourth step is as follows.
1) a method of neutralizing with a base using a diol containing a carboxyl group as a diol component, 2) a method of prepolymerizing with an alkyl dialkanolamine having a tertiary amino group, and a method of quaternizing, 3) having a tertiary amino group A method of prepolymerizing with an alkyl dialkanolamine, neutralizing with an acid to form an amine salt, and 4) a method of using a highly water-soluble polyol, for example, ethylene glycol as a urethane component. Or 5) a method in which an unsaturated monomer having one or more carboxyl groups in the same molecule is copolymerized and neutralized with a basic substance; 6) an unsaturated monomer having a polyoxyethylene skeleton in the same molecule And a method of combining a plurality of the above methods 1 to 6. In the present invention,
Although it is preferable not to use a surfactant, a small amount of a surfactant may be used in combination for the purpose of improving the mechanical stability of the polyurethane composite resin dispersion.

Examples of the surfactant include fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates,
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.

Examples of the basic compound used for aqueous conversion include 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 unsaturated monomer solution of the polyurethane, it is necessary to appropriately select a neutral compound because the compatibility with the solution and the stability after dispersion in water may differ depending on the type of the basic compound. 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.

In the aqueous dispersion, the total amount of the polyurethane and the polyacryl is preferably within a range of 70% by weight or less. If it is more than 70% by weight, aggregates are easily formed, and it is difficult to obtain a uniform polymer.

The removal of the organic solvent having a hydroxyl group in the fifth step is preferably carried out by distillation. The aqueous urethane composite resin can be obtained by distillation under heating or heating under reduced pressure.

The aqueous urethane composite resin of the present invention thus obtained is excellent in water-based paints, inks, adhesives, vehicles for coating agents, binder resins, and also has excellent adhesion to polyolefins. Can also be used as a primer.

[0033]

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.

[0034]

Example 1 A 4-neck 2000 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, 188 parts of butyl acrylate, and a number average molecular weight were obtained. About 2,000
(Hydroxyl value 56) polytetramethylene glycol6.
7 parts, 1.4 parts of dimethylolpropionic acid
The temperature was raised to 0 ° C. Under stirring, 3.7 parts of diphenylmethane diisocyanate and 0.01 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. Actual measured NCO% = 0.4
5%. Number average molecular weight 16,700.

The prepolymer monomer solution was cooled to 30 ° C., and 30 parts of isopropyl alcohol was added. Under stirring, a solution in which 0.2 part of adipic dihydrazide was 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 had a molecular weight of about 31,000. Next, isopropyl alcohol 5
70 parts of azobisisobutyronitrile and 7.8 parts of azobisisobutyronitrile were added, and an acrylic polymerization reaction was carried out at 80 ° C. for 6 hours under a nitrogen atmosphere. To this solution, 1.1 parts of triethylamine and 750 parts of distilled water were added, and the polyurethane composite resin solution was dispersed in water. Next, after attaching a distilling device to the flask, the temperature of the aqueous dispersion was raised to 80 ° C., and isopropyl alcohol was distilled off. Since isopropyl alcohol and a small amount of water azeotrope, the distillation amount was 750 parts. After the distillation, a urethane composite resin dispersion (a) was obtained.

[0036]

EXAMPLE 2 A four-necked 2000 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, 40 parts of butyl acrylate, and a number average molecular weight were obtained. 158 parts of polypropylene glycol 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, 109.3 parts of diphenylmethane diisocyanate and 0.2 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. Actual NCO% = 2.1%. Number average molecular weight 4,400.

The prepolymer monomer solution was cooled to 30 ° C., and 10 parts of isopropyl alcohol was added. Under stirring, a solution in which 14.3 parts of isophoronediamine was dissolved in 50 parts of distilled water was added dropwise over 30 minutes, and the reaction was continued for 1 hour. The polyurethane thus obtained has a molecular weight of about 2
It was 8,000. 740 parts of isopropyl alcohol and 1.6 parts of azobisisobutyronitrile were added, the temperature was raised to 80 ° C. while introducing nitrogen gas into the flask, and acrylic polymerization was performed for 6 hours. Here, 29 parts of triethylamine,
940 parts of distilled water was added, and the temperature of the aqueous dispersion was raised to 80 ° C., and isopropyl alcohol was distilled off to obtain an aqueous urethane composite resin dispersion (b). The distillation amount was 938 parts.

[0038]

Example 3 A four-necked 2000 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 70 parts of methyl methacrylate were used. Department,
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, and the temperature was raised to 80 ° C.
The reaction was carried out for a time to obtain a urethane prepolymer monomer solution. Actual NCO% = 0.75%. Number average molecular weight 9,50
0.

The monomer solution of the prepolymer was cooled to 30 ° C., and 20 parts of isopropyl alcohol was added. Under stirring, a solution of 3.8 parts of adipic dihydrazide dissolved in 50 parts of distilled water was added dropwise over 30 minutes, and the reaction was continued for 1 hour. The resulting polyurethane had a molecular weight of about 33,000. Further, 580 parts of isopropyl alcohol and 4.8 parts of azobisisobutyronitrile were added, and the temperature was raised to 80 ° C. while introducing a nitrogen gas into the flask to carry out acrylic polymerization for 6 hours. To this, 14.4 parts of triethylamine and 700 parts of distilled water were added, the temperature of the aqueous dispersion was raised to 80 ° C., and isopropyl alcohol was distilled off to obtain an aqueous urethane composite resin dispersion (c). The distillation amount at this time was 750 parts.

[0040]

Comparative Example 1 A four-necked 2000 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 70 parts of methyl methacrylate were used. Department,
95.4 parts of polytetramethylene glycol having a number average molecular weight of about 2,000 (hydroxyl value: 56) and 19.1 parts of dimethylolpropionic acid were 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. Actual NCO% = 0.3%. Number average molecular weight 25,000
0.

The monomer solution of the prepolymer was cooled to 30 ° C., and 20 parts of isopropyl alcohol was added. A solution consisting of 1.8 parts of adipic dihydrazide and 50 parts of distilled water was added dropwise over 30 minutes, and the reaction was continued for 1 hour. The polyurethane thus obtained has a molecular weight of about 43,0.
00. Next, isopropyl alcohol 580
And 4.8 parts of azobisisobutyronitrile were added, the temperature was raised to 80 ° C. while introducing nitrogen gas into the flask, and acrylic polymerization was carried out for 6 hours. Next, triethylamine 1
4.4 parts and 750 parts of distilled water were added, and the aqueous dispersion was heated to 80 ° C.
And the isopropyl alcohol was distilled off to obtain an aqueous urethane composite resin dispersion (d). The distillation amount at this time is 7
50 parts.

[0042]

Comparative 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 nitrogen, and 200 parts of methyl ethyl ketone, a number average molecular weight of about 2,000 (hydroxyl group) 56) of polypropylene glycol having a valency of 56) and dimethylolpropionic acid 1
9.1 parts 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. Measured NCO% =
1.8%. Number average molecular weight 5,000.

The prepolymer was cooled to 30 ° C., and a solution composed of 8.2 parts of adipic dihydrazide and 50 parts of distilled water was added dropwise over 30 minutes. Further, the chain extension reaction was continued for 1 hour. Next, 14.4 parts of triethylamine and 35 parts of distilled water were used.
After 0 parts were added and the solvent was removed, an aqueous urethane resin dispersion (e) was obtained.

The methods for evaluating the aqueous urethane composite resins (a to c, d) and the aqueous urethane resin (e) obtained in Examples 1 to 3 and Comparative Examples 1 and 2 are described below. The results are shown in Table 1. a) Water dispersibility Water dispersibility in the fourth step ◎ Water dispersibility can be easily achieved. ○ Water dispersibility. △ Thickening is observed when dispersing in water, but dispersible. × Not significantly thickened or dispersed in water when dispersed in water.

B) Formation of Agglomerates in the Fifth Step After the organic solvent was distilled off, the dispersion was filtered through a 100-mesh wire gauze, and the extent of the filtration residue was examined. ◎ There is no filtration residue. ○ Almost no filtration residue. △ There is a little filtration residue. × There is considerable filtration residue.

C) Adhesion to PET The aqueous urethane composite resin (a to c) was placed on a PET film.
D) and an aqueous urethane resin (e) were applied using a 2.5 MIL applicator. After drying at 60 ° C. for 3 minutes, the temperature was returned to room temperature, and the adhesion was examined by a cellophane tape peeling test. ◎ Does not peel at all. ○ Almost no peeling. △ Peel a little. X: It peels considerably.

D) Weather resistance The aqueous urethane composite resin (a to c, d) is provided on a slate plate.
Then, a film of an aqueous urethane resin (e) was formed, and the film was exposed to a weathering tester (Sunshine weather meter) for 200 hours, and the adhesion of the film after exposure was examined by a cellophane peel test. ◎ The film does not come off at all. ○ The film is hardly peeled off. △ The film peeled off a little. C: The film peels considerably.

[0048]

[Table 1]

[0049]

According to the present invention, the production method is excellent in cost because a conventional urethane synthesis solvent is not used for the prepolymerization reaction, and the solvent removal step can be omitted if necessary. Further, in the production process, since the urethane reaction is performed in the unsaturated monomer, the urethane resin and the unsaturated monomer can be directly and chemically bonded, thereby giving a resin form different from that of the blend system. be able to.
The water-based urethane composite resin obtained in this way has the advantages of urethane, such as weather resistance and alkali resistance, which are disadvantages of urethane resin without impairing the adhesion to the substrate, abrasion resistance, solvent resistance, and impact resistance. In addition, since the physical properties such as heat resistance can be improved, the present method has made it possible to provide a very practical method for producing an aqueous urethane composite resin.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08G 18/66 C08G 18/66 A C08L 25/02 C08L 25/02 57/04 57/04 75/08 75/08 C09D 125 / 02 C09D 125/02 157/04 157/04 175/08 175/08 C09J 125/02 C09J 125/02 157/04 157/04 175/08 175/08 (72) Inventor Tsukasa Otsuki Kyobashi, Chuo-ku, Tokyo Chome 3-13 Toyo Inki Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. To obtain an aqueous urethane composite resin comprising a radical polymer of urethane and an unsaturated monomer, a) reacting a polyol with an organic polyisocyanate in an unsaturated monomer having no active hydrogen; First step of obtaining an unsaturated monomer solution (A) of a urethane prepolymer having an isocyanate group at a terminal and having a number average molecular weight of 20,000 or less b) Chain-extending (A) in the presence of an organic solvent having a hydroxyl group A) a second step of obtaining a polyurethane solution (B); c) a radical polymerization of (B) to obtain a polyurethane-polyacrylic solution (C); d) a dispersion of (C) in water; A fourth step of obtaining an aqueous dispersion (D) e) a fifth step of removing an organic solvent having a hydroxyl group from (D), a method for producing an aqueous urethane composite resin, comprising: . 2. The method for producing an aqueous urethane composite resin according to claim 1, wherein the urethane prepolymer is 5 to 60% by weight in the first step. 3. The method for producing an aqueous urethane composite resin according to claim 1, wherein in the first step, the unsaturated monomer having no active hydrogen comprises a monomer containing an aromatic monomer. . 4. The method for producing an aqueous urethane composite resin according to claim 1, wherein in the first step, the urethane prepolymer contains polyethylene glycol as an essential component. 5. The method for producing an aqueous urethane composite resin according to claim 1, wherein the organic solvent having a hydroxyl group in the second step contains isopropyl alcohol.