JP3526934B2 - Aqueous dispersion composition of cold-crosslinkable copolymer and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a one-pack type coating film which is excellent in storage stability, crosslinks at room temperature after coating and drying, is tough and has excellent water resistance, solvent resistance, and adhesion to a substrate. And a room temperature crosslinkable copolymer aqueous dispersion composition suitable for use in paints and coatings.

[0002]

2. Description of the Related Art In the field of paints and coatings, a urethane crosslinking system in which a hydroxyl group-containing polymer such as an acrylic polyol is cured with a polyisocyanate-based crosslinking agent has sufficient reactivity because the isocyanate group is highly reactive. It was difficult to provide in liquid form.

On the other hand, m-isopropenyl-α,
Since the isocyanate group of α'-dimethylbenzyl isocyanate (product name m-TMI of American Cyanamid Co., Ltd.) is relatively low in reactivity, an aqueous dispersion obtained by vinyl copolymerizing this is "Journal of coating technology ". 1986 May 5
8: 773, pp. 43-47. This document describes that the isocyanate group can be introduced into the copolymer by carrying out the polymerization reaction by low-temperature redox polymerization, and that moisture crosslinking is carried out by adding a catalyst at the time of use. However, there were problems that the reaction of the isocyanate group gradually occurred during the polymerization reaction and during storage, the physical properties of the coating film changed with time, and the storage stability of the aqueous dispersion containing the catalyst was not sufficient. .

Further, as a method of applying the urethane crosslinking system to an aqueous polymer, a copolymer containing an unsaturated monomer containing a blocked isocyanate group in which an isocyanate group is blocked with a masking agent and a monomer containing active hydrogen. A one-liquid type aqueous dispersion comprising the above is disclosed in JP-A-49-52226. Furthermore, an acrylic resin containing a blocked isocyanate group and a hydroxyl group is disclosed in JP-A-5-24.
No. 7175. However, in these methods, since the dissociation temperature of the blocked isocyanate group is high, a baking treatment at 100 ° C. or higher is required, and the room temperature crosslinkability at about 20 to 50 ° C. which is the object of the present invention cannot be obtained.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention provide a urethane-crosslinking type vinyl copolymer aqueous dispersion which is a one-pack type which is excellent in storage stability and which rapidly undergoes a crosslinking reaction at room temperature after coating and drying. For that purpose, a method for producing a vinyl copolymer aqueous dispersion containing a stable free isocyanate group by preventing a crosslinking reaction during the polymerization reaction, and the copolymer aqueous dispersion and the crosslinking reaction at room temperature. The present invention has been achieved as a result of intensive research on obtaining a room-temperature crosslinkable aqueous dispersion composition having good stability in one solution by mixing with an aqueous dispersion of a copolymer having a reactive group to cause it.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a vinyl copolymer aqueous dispersion (A) containing a free isocyanate group, and a copolymer containing a hydroxyl group which is compatible with (A). A composition with a vinyl copolymer aqueous dispersion (B) having a gel fraction of 30 to 90% by weight,
An organic compound in which the mixing ratio of (B) / (A) is 0.1 to 1.2 equivalents of hydroxyl groups with respect to 1 equivalent of isocyanate groups and, if necessary, emulsified and dispersed with a surfactant in advance. It is a room temperature crosslinkable copolymer aqueous dispersion composition comprising a metal compound.

Further, the vinyl copolymer of the above (A) is
-And / or p-isopropenyl-α, α'-dimethylbenzylisocyanate 1-20% by weight, carboxyl group and / or amide group-containing monomer 0.1-5% by weight, and no other active hydrogen Vinyl monomer 98.9
To 75% by weight, and the monomer mixture forming the copolymer is added to water, an emulsifier, a tertiary amine compound, and a redox polymerization initiator in the presence of pH 6 to 8 and 70 ° C. or less. Copolymerization Obtained by Emulsion Polymerization at Various Temperatures
The aqueous dispersion (A) is compatible with (A) and has no gel content.
Hydroxyl group-containing vinyl copolymer having a rate of 30 to 90% by weight
The combined aqueous dispersion (B) has a mixing ratio (B) / (A) of
Hydroxyl groups are 0.
A method for producing a room temperature crosslinkable copolymer aqueous dispersion composition, which comprises mixing in an amount of 1 to 1.2 equivalents .

Furthermore, the composition of the present invention is at 25 ° C., 1
In infrared absorption spectrum measurement of the time after drying of the film, the wave with respect to the absorption intensity at a wavelength of 2950 cm ^-1
The absorbance ratio of the absorption intensity at a length of 2255 cm ⁻¹ is 0.
It is 07 or more.

The vinyl group-containing copolymer aqueous dispersion (A) containing a free isocyanate group of the present invention comprises a monomer 1 having at least one isocyanate group and at least one radical-polymerizable double bond in one molecule. -20% by weight and 99-80% by weight of another vinyl monomer are emulsion-polymerized to form an aqueous dispersion of a copolymer.

Examples of the monomer having an isocyanate group include methacryloyl isocyanate, 2-isocyanate ethyl methacrylate, a reaction product of isophorone diisocyanate and 2-hydroxyethyl (meth) acrylate, and m- and / or p-isopropenyl-. α,
One or two or more selected from α′-dimethylbenzyl isocyanate and the like can be used, but in particular, m
-And / or p-isopropyl-α, α′-dimethylbenzylmeisocyanate is used to stably introduce an isocyanate group into the copolymer, and the hydroxyl group-containing copolymer aqueous dispersion described below is blended. It is preferable because good storage stability of the composition is obtained. The amount of the isocyanate group-containing monomer used in the copolymer (A) of the present invention is from 1 to 20 in order to impart appropriate crosslinking to the storage stability of the aqueous dispersion composition of the present invention and the dry coating film. %, Preferably 2-10% by weight.

Another vinyl monomer copolymerizable with the monomer having an isocyanate group is a vinyl monomer containing a radically polymerizable carboxyl group and / or amide group.
˜5% by weight, and 98.9-75% by weight of other non-active hydrogen containing monomers.

The carboxyl group-containing vinyl monomer is selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride and the like.
One kind or two or more kinds can be used, and the amide group-containing monomer is selected from acrylamide, methacrylamide, N-ethyl (meth) acrylamide and the like. The copolymerization of the carboxyl group-containing monomer and / or the amide group-containing monomer is carried out by the copolymer aqueous dispersion (A) of the present invention.
The amount of the monomer to be copolymerized is 0.1 to 5% by weight, which is necessary for imparting mechanical stability and chemical stability to
It is preferably 1 to 3% by weight.

As the other monomer having no active hydrogen, a monomer having radical polymerizability and not reacting with an isocyanate group is preferable, and specifically, styrene, α
-Aromatic vinyl monomers such as methylstyrene: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth)
(Meth) acrylic acid esters such as acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate: perfluorocyclohexyl (meth) acrylate, vinyl fluoride, vinylidene fluoride Fluorine-containing vinyl monomers such as: and (meth) acrylonitrile, vinyl acetate, vinyl propionate, vinyl ethyl ether, vinyl butyl ether, vinyl chloride,
One kind or a mixture of two or more kinds selected from vinylidene chloride and the like is used.

A monomer having the above-mentioned isocyanate group,
A mixture of a monomer having a carboxyl group and / or an amide group and another monomer having no active hydrogen is treated with water,
In the presence of an emulsifier, a tertiary amine compound, and a redox polymerization initiator, emulsion polymerization is carried out at a pH of 6 to 8 and at a temperature of 70 ° C. or lower to give an aqueous dispersion of a vinyl copolymer containing a free isocyanate group (A ) Is manufactured.

In the present invention, it is important that emulsion polymerization is carried out while suppressing the reaction of isocyanate groups in the polymerization step. The present inventors have shown that the pH during the polymerization reaction is adjusted to 6 to 8 by using a tertiary amine compound, and that the low temperature polymerization method using a redox polymerization initiator can suppress the reaction of the isocyanate group. Obtained.

The tertiary amine compound used for pH adjustment of the present invention is selected from trimethylamine, triethylamine, dimethylcyclohexylamine, N-tetramethylhexane-1,6-diamine, N-pentamethyldiethylenetriamine and the like. The amount used is 0. 1 with respect to the amount of the carboxyl group-containing vinyl monomer to be copolymerized and the equivalent amount of the sum of acidic groups due to decomposition of the polymerization initiator used.
Use 8-1.5 equivalents.

The redox polymerization initiator used in the present invention is an initiator system capable of forming a free radical by a combination of an oxidizing agent comprising a suitable peroxide and a suitable reducing agent, and is well known in the art. Can be selected from the available redox initiator systems. Examples of suitable oxidants include benzoyl peroxide,
One or more selected from organic peroxides such as di-t-butyl peroxide and cumene hydroperoxide, persulfates and hydrogen peroxide can be used. Further, as an example of a suitable reducing agent, one or more selected from sodium formaldehyde sulfonate, ascorbic acid, sulfite, a metal compound having a reducing property and the like are used in combination. A preferred redox initiator combination is di-t-butyl peroxide / sodium formaldehyde sulfonate / ferrous sulfate, or persulfate /
It is a redox polymerization initiator system such as ascorbic acid / ferrous sulfate.

It is effective to prevent the reaction of the isocyanate group by carrying out the polymerization reaction at a temperature as low as possible, and it is 70 ° C. or less, preferably 25 to 60 ° C.

The emulsifier used in the present invention is not particularly limited, and an emulsifier used in ordinary emulsion polymerization,
For example, one or two selected from anionic emulsifiers, nonionic emulsifiers, reactive emulsifiers, polymeric dispersion stabilizers and the like.
Used in combination of more than one species. Further, nitrogen substitution in the polymerization reaction is effective in increasing the polymerization rate and improving the polymerization rate, and if necessary, a polymerization degree adjusting agent, a particle size adjusting agent or the like may be used.

Vinyl copolymer aqueous dispersion (A) containing isocyanate groups produced by the method of the present invention
In, the isocyanate group is introduced into the copolymer at a ratio close to the charging ratio of the isocyanate group-containing monomer. Therefore, the film immediately after drying this aqueous dispersion at room temperature after application has a low degree of formation of crosslinks derived from isocyanate groups, and therefore dissolves in a good solvent of the copolymer, or has a low gel fraction and high swelling. Indicates the degree. Further, by measuring the infrared absorption spectrum from the coating, indicating a sharp characteristic absorption at the wavelength 2255cm ^-1 based on the isocyanate groups. This absorption strength depends on the ratio of the charged isocyanate group-containing monomer, but in order to achieve the effects of the present invention, the film of the film immediately after drying from the aqueous copolymer dispersion (A) at 25 ° C. for 1 hour is used. Measure the infrared absorption spectrum,
On the absorption intensity based on methylene linkages in the wavelength 2950 cm ^-1, the absorbance ratio of the absorption intensity at a wavelength of 2255cm ^-1 is preferably at least 0.1 or more. Furthermore, the absorbance ratio in the composition of the present invention containing the copolymer aqueous dispersion (A) and the hydroxy group-containing copolymer aqueous dispersion (B ) described below is at least 0.07 or more. is necessary. Absorbance ratio is 0.
When it is 07 or less, the composition of the present invention is formed and crosslinked at room temperature to have a low crosslink density, and sufficient solvent resistance and adhesion to a substrate cannot be obtained, which is not preferable.

The hydroxyl group-containing vinyl copolymer aqueous dispersion (B) used in the composition of the present invention is compatible with the isocyanate group-containing copolymer aqueous dispersion (A) and has a gel content. It is an aqueous dispersion of a copolymer having an appropriate partial cross-linkage defined as a ratio . The term "compatibility" as used herein means a state in which a film obtained by applying a composition obtained by mixing the above-mentioned aqueous dispersions (A) and (B) in an arbitrary ratio and drying the composition becomes transparent without any turbidity. . Also, the gel fraction is
The combined aqueous dispersion (B) is applied to a polypropylene film, and a 100 μm-thick film dried at 25 ° C. for 24 hours is immersed in ethyl acetate for 24 hours to measure the weight ratio of the insoluble portion to the weight before immersion. . The gel fraction is required to be 30 to 90% by weight, preferably 50 to 80% by weight. If it is 30% by weight or less, the solvent resistance of the crosslinked film obtained by drying the composition of the present invention at room temperature is not sufficient, and if it is 90% by weight or more, the film-forming property of the composition is lowered and the mechanical properties of the crosslinked film are reduced. Is reduced, which is not preferable.

The hydroxyl group-containing vinyl copolymer aqueous dispersion (B) contains 1 to 1 monomer having at least one hydroxyl group and one radically polymerizable double bond in each molecule.
It comprises an aqueous dispersion of a copolymer obtained by emulsion-polymerizing a mixture of 15% by weight, 0.1 to 5% by weight of a crosslinking monomer, and 98.9 to 80% by weight of another vinyl monomer.

As the monomer having a hydroxyl group,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2,3-dihydroxypropyl acrylate, 2-hydroxy-3-ethoxyethyl acrylate, 2-hydroxy-3- One or more selected from phenoxyethyl methacrylate and the like can be used. The proportion of monomers having hydroxyl groups to be copolymerized is 1 to 15% by weight, preferably 2 to 8% by weight of the monomer mixture.

As the cross-linking monomer, a monomer having two or more radically polymerizable double bonds in one molecule,
Alternatively, it is selected from radically polymerizable monomers having a reactive group that forms crosslinks between polymers during the polymerization reaction. Examples of the monomer having two or more radically polymerizable double bonds in one molecule include divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate. Etc. Further, as the monomer having a reactive group that forms crosslinks between polymers during the polymerization reaction, a monomer containing a reactive group such as an isocyanate group, an N-alkylol-substituted amide group, a glycidyl group, or an alkoxysilyl group. By a method such as combining the body with a monomer containing a carboxyl group and / or a hydroxyl group. Examples of these monomers include (meth) acryloyl isocyanate, 2-isocyanatoethyl methacrylate, m- and / or p-isopropenyl-α, α ′.
-Dimethylbenzyl isocyanate, N-methylol (meth) acrylate, glycidyl (meth) acrylate, (meth) acryloxypropyltrimethoxysilane, tetramethoxysilylpropyl (meth) acrylate and the like can be mentioned. One or more selected from these monomers are used in an amount of 0.1 to 5% by weight.

Further, the other vinyl monomer is an aqueous vinyl copolymer dispersion (A) containing the above isocyanate group.
The radically polymerizable carboxyl group and / or amide group-containing vinyl monomer used for 0 to 5% by weight, and other non-active hydrogen-containing monomer 98.9 to 82% by weight. In order to obtain compatibility, it is preferable to select the same type as the copolymer aqueous dispersion (A) and adjust the composition ratio.

Emulsion polymerization from the above monomer mixture can be carried out by a usual method. In this case, the pH of the polymer aqueous dispersion (B) should be adjusted to 6 to 8 in order to keep the isocyanate group in the composition of the present invention mixed with the copolymer aqueous dispersion (A) stable. It is particularly preferable to use a tertiary amine compound such as trimethylamine or triethylamine as the neutralizing alkali.

Each of the aqueous copolymer dispersions (A) and (B) of the present invention needs to be dried at room temperature to form a tough film. The glass transition temperature of the copolymers (A) and (B) is preferably about -30 ° C to + 30 ° C.
The glass transition temperature of the copolymer is mixed with a copolymer of (A) (B) is equal to, or particles fusing to set 5 to 10 ° C. lower the copolymer (A) It is preferable because it has the effect of increasing the mutual compatibility of the copolymers in the process and further promoting the crosslinking reaction.

The room-temperature crosslinkable copolymer aqueous dispersion composition of the present invention is a copolymer of (A) containing a hydrophobic isocyanate group mainly distributed inside the particles in water as a medium.
Since the body particles and the copolymer particles (B) containing a hydrophilic hydroxyl group distributed mainly on the surface of the particles are independently dispersed, it is considered that the particles are stably held during storage. In the process of applying and drying this, particles are fused to each other to form a film and both reactive groups come close to each other, whereby a crosslinking reaction proceeds. The mixing ratio of (A) and (B) is copolymer
Based on 1 equivalent based on the weight of the isocyanate group-containing monomer charged in the aqueous dispersion (A) , the aqueous copolymer content
Mix 0.1 to 1.2 equivalents based on the weight of the charged hydroxyl group-containing monomer in the dispersion (B) .
When the amount is 0.1 equivalent or less, the rate of crosslinking of the isocyanate group with the hydroxyl group is small, so that the crosslinking reaction rate is slow and the solvent resistance is poor, and when it is 1.2 equivalent or more, the water resistance and the storage stability are deteriorated. Not good for Particularly preferable mixing ratio is 0.3 to 0.8 equivalents of hydroxyl groups to 1 equivalent of isocyanate groups.

The aqueous dispersion composition of the present invention has the above (A)
It is stable when the aqueous dispersions of (B) and (B) are mixed, and the physical properties are small even when left at room temperature for 1 to several months.
Can be stored and stored in liquid form. Moreover, after coating, it is 2-10 at room temperature.
Crosslinking is completed in a day to form a film having excellent water resistance, toughness and solvent resistance, and also has excellent adhesion to the base material.

In the aqueous dispersion composition of the present invention, an organometallic compound can be used as a catalyst for promoting the crosslinking reaction, if necessary. Organometallic compounds used can be formulated and emulsified by previously surfactant, the water
Dispersion (A) and aqueous dispersion (B) are uniformly mixed ,
It is preferable because the storage stability after mixing can be extended. The content of the organometallic compound is 0.01 to 5% by weight, preferably 0.1 to 5% by weight based on the weight of (A) and (B).
It is 2% by weight. Examples of the organometallic compound include dibutyltin dilaurate, tetrabutyltin, tin octylate,
Examples include tetraisopropyl titanate and tetrabutyl titanate. When these catalysts are blended immediately before coating or several days before coating, they are effective in shortening the crosslinking time at room temperature without impairing the stability of the composition of the present invention.

In addition, the copolymer aqueous dispersion composition of the present invention may include pigments and various additives (preservatives, ultraviolet absorbers, antioxidants, leveling agents, thickeners) usually added as a paint, if necessary. , A film-forming aid, an anti-sagging agent, and a matting agent).

The composition of the present invention can be suitably used, for example, as a paint for wood, plastics, inorganic building materials or metal surfaces. Further, it is also useful as a coating agent for non-woven fabric, paper, leather, etc., and an adhesive for laminating composite plastic films.

【Example】

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, parts or% means parts by weight or% by weight unless otherwise specified.
Indicates.

Production Example A. Isocyanate group-containing copolymer
Production of Aqueous Dispersion (A) (Redox Polymerization A-1, A-2, A-3) 50 parts of deionized water in a reactor equipped with a stirring group, a reflux condenser, a nitrogen gas introduction part, and a dropping funnel. , Sodium lauryl sulfate 0.2 part, polyoxyethylene nonyl phenyl ether 0.4 part, ferrous sulfate heptahydrate 0.02 part, t-butyl hydroperoxide 0.1 part, formaldehyde sulfonic acid 0.1 part And A-1, A-2, and A in Table 1 below.
Initial charging was performed using 10% of the monomer emulsion shown in -3. Then, the temperature was raised to 50 ° C. while introducing nitrogen gas, and initial polymerization was performed for 30 minutes. Subsequently, 90% of the monomer emulsion was added dropwise over 3 hours. During that time, 2 parts of a 5% aqueous solution of formaldehyde sulfonic acid was added at 1 hour intervals in 3 divided portions. 1 hour after the completion of the dropping, 0.1 part of t-butyl hydroperoxide and 2 parts of a 5% formaldehyde sulfonic acid aqueous solution were added and polymerization was continued for another 2 hours. During that time, the polymerization temperature was maintained at 50 to 53 ° C. After the polymerization reaction, the solid content concentration was adjusted to 45% with deionized water.

(Normal Polymerization A-4) In the same reactor as above, 50 parts of deionized water, 0.2 part of sodium lauryl sulfate,
0.4 parts of polyoxyethylene nonyl phenyl ether,
0.1 part of ammonium persulfate and A- in Table 1 below.
Initial charging was performed using 10% of the monomer emulsion shown in 4. Then, the temperature was raised to 80 ° C. while introducing nitrogen gas, and initial polymerization was performed for 30 minutes. Subsequently, the remaining 90% of the monomer emulsion was added dropwise over 3 hours. Polymerization was continued for 2 hours. During that time, the polymerization temperature was maintained at 80 to 81 ° C. After the polymerization reaction, the solid content concentration was adjusted to 45% with deionized water.

From the infrared absorption spectrum of the film immediately after coating the aqueous dispersion of the copolymers A-1 to A-4 obtained above on a release paper and drying at 25 ° C. for 1 hour, the wavelength 29
The results of measurement of the absorbance ratio of the absorption intensity based on the isocyanate groups of a wavelength 2255cm ^-1 for the absorption intensity based on methylene linkages in the 50 cm ^-1 referred together in Table 1.

Production Example B. Hydroxyl group-containing copolymer water
Preparation of the organic dispersion liquid (B) In the same reactor as in the above Preparation Example A, 50 parts of deionized water, 0.2 part of sodium lauryl sulfate, 0.4 part of polyoxyethylene nonylphenyl ether, and ammonium persulfate of 0.
Initial charging was carried out using 1 part and 10% of the monomer emulsions shown in B-1, B-2 and B-3 of Table 2. Then, the temperature was raised to 80 ° C. while introducing nitrogen gas, and initial polymerization was performed for 30 minutes. Subsequently, the remaining 9 of the monomer emulsion
0% was added dropwise over 3 hours. Polymerization was continued for 2 hours. During that time, the polymerization temperature was maintained at 80 to 81 ° C. After the polymerization reaction, the solid content concentration was adjusted to 45% with deionized water.

From the aqueous dispersions of the copolymers of B-1 to B-3 obtained above, 25 were formed on a polypropylene film.
Table 2 also shows the results of measuring the gel fraction from the measurement of the insoluble portion after drying at 24 ° C. for 24 hours to form a 100 μm-thick dry film and immersing in ethyl acetate for 24 hours.

Production Example C. Preparation of curing catalyst water dispersion 15 parts of dibutyltin dilaurate as an organometallic compound, 20 parts of butyl cellosolve acetate, 4 parts of polyoxyethylene nonylphenyl ether, 2 parts of sodium lauryl sulfate and 65 parts of deionized water were mixed and mixed with a homogenizer. Emulsified.

[0040]

[Table 1] m-TMI: m-isopropenyl-α, α'-dimethylbenzyl isocyanate

[0041]

[Table 2]

Examples 1 to 4 and Comparative Examples 1 to 4 Aqueous dispersions obtained according to Preparation Example A, Preparation Example B and preparation
The aqueous dispersion obtained in Example C was mixed at the blending ratio shown in Table 3 to prepare a crosslinkable copolymer aqueous dispersion composition. A film was prepared from the aqueous dispersion composition immediately after preparation and stored at 30 ° C. for 1 month, and the infrared absorption spectrum was measured to determine the absorbance ratio of the isocyanate group to the methylene bond. Further, each aqueous dispersion composition was applied onto a polypropylene film so that the dry film thickness was 100 μ, and left at room temperature for 1 week to prepare a film. The film was cut into 25 cm square pieces and immersed in ethyl acetate for 24 hours, and then the gel fraction and the weight swelling degree were determined. Further, a glass plate is coated with a solvent type vinyl chloride-vinyl acetate resin-based coating material and dried to prepare a base coating film having a thickness of 100 μ, and each aqueous dispersion composition is applied to the base coating surface to give a dry coating thickness of 100 μ. After being applied as described above and allowed to stand at room temperature for 1 week, the adhesion, solvent resistance and water resistance were measured by the test methods described below. The test results are summarized in Table 3. As a result, the stability of the isocyanate group contained in the aqueous dispersion composition of the present invention is high, and excellent storage stability is exhibited. In addition, the dry film has a high crosslink density because it exhibits a high gel fraction and a low degree of swelling,
It can be seen that the coating film has excellent solvent resistance, water resistance and adhesion to the base paint.

[0043]

[Table 3]

[0044] Examples 5 and 6 and Comparative Examples 5 and 6 Production Example A, an aqueous dispersion thus obtained in Production Example B and production
The aqueous dispersion obtained in Example C was mixed at the blending ratio shown in Table 4 to prepare a crosslinkable copolymer aqueous dispersion composition. Each water
Of a water- soluble dispersion composition on a glass plate to a dry film thickness of 150 μ
Was applied and dried at room temperature for 2 weeks to prepare a film, and the tensile properties were measured by the test methods described below. Further, 100 parts by weight of each aqueous dispersion composition and 55 parts by weight of a pigment paste having the following formulation were mixed to prepare an emulsion paint. A solvent-type acrylic-urethane resin paint was applied to the slate board and the base, and the coating was exposed for 2000 hours with a weatherometer so that the thickness of the dry film would be 100μ, and then room temperature for 2 weeks. After drying, a coating film test was conducted. The above test results are summarized in Table 4. As a result, it can be seen that the film obtained from the aqueous dispersion composition of the present invention is superior in toughness as compared with the comparative example, and is also excellent in adhesion, water resistance and solvent resistance of the coating film.

[0045]

[Table 4]

Formulation of pigment paste Titanium oxide Taipaque R-960 (Ishihara Sangyo) 70.0 parts Pigment dispersant Orotan 7313D (Rohm and Haas) 1.0 Wetting agent Newcol 556 (Nippon Emulsifier Co., Ltd.) 1.0 Foaming agent Adeka B-740 (Adeka Corporation) 0.5 Thickener Adeka UH-420 (Adeka Corporation) 0.1 Membrane forming aid Texanol CS-12 (Chisso Corporation) 5.0 Ion exchange Water 22.4 Total 100.0 parts

[0047] Test Methods Adhesion; increments crosscut of 5mm square in NT cutter, Se
Observe the peeled state when peeled off with Rohan tape .
◎ No peeling, ○ 10% or less peeling, △ 40% or less peeling, × 40% or more peeling solvent resistance; spotted with toluene and observed by rubbing with a finger.
◎ No abnormality, ○ Slightly softened, △ Swelled, cracked,
× Dissolved water resistance: A coated plate whose back and side surfaces were sealed with epoxy resin was observed after being immersed in water for 3 days. ◎ No abnormality,
○ Slight swelling, △ Partial swelling, × Partial peeling Tensile test: The film was punched out with dumbbell No. 2 and measured with an Instron tensile tester at 20 ° C., chuck distance 50 mm, and tensile speed 200 mm / min.

[0048]

EFFECTS OF THE INVENTION The room temperature crosslinkable aqueous dispersion composition of the present invention comprises a vinyl copolymer aqueous dispersion containing an isocyanate group and a vinyl copolymer containing a hydroxyl group, as is clear from Examples and Comparative Examples. It has good storage stability when mixed with an aqueous dispersion, and when it is applied and dried, it undergoes a crosslinking reaction at room temperature, is tough, and has water resistance, solvent resistance, and excellent adhesion to the underlying substrate. Give a membrane. Therefore, the composition of the present invention can be suitably used as a paint for wood, plastics, inorganic building materials, or metal surfaces. It can also be applied as a coating agent for non-woven fabric, paper, leather, etc., and an adhesive for laminating composite plastic films.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08F 212/00-212/36 C08F 220/00-222/40 CA (STN ) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. A vinyl copolymer aqueous dispersion (A) containing a free isocyanate group, and a copolymer having a hydroxyl group which is compatible with (A) and has a gel fraction of 30 to 90% by weight. % Vinyl copolymer aqueous dispersion (B), wherein the mixing ratio (B) / (A) is 0.1-1.
A room temperature crosslinkable copolymer aqueous dispersion composition, which is mixed in an amount of 2 equivalents. 2. The vinyl copolymer as the component (A) of claim 1 is m- and / or p-isopropenyl-α, α'-.
Dimethylbenzyl isocyanate 1 to 20% by weight and carboxyl group and / or amide group-containing monomer 0.1 to 5
2. The room temperature crosslinkable copolymer aqueous dispersion composition according to claim 1, which is a copolymer with 1% by weight and 98.9 to 75% by weight of another vinyl monomer having no active hydrogen. object. 3. The room temperature crosslinkable copolymer aqueous dispersion composition according to claim 1, which further comprises an organometallic compound which has been previously emulsified and dispersed with a surfactant. 4. The infrared absorption spectrum of the film after drying at 25 ° C. for 1 hour has a wavelength of 2950 cm ⁻¹ .
The room temperature crosslinkable copolymer aqueous dispersion according to any one of claims 1 to 3, wherein the absorbance ratio of the absorption intensity at a wavelength of 2255 cm ^{-1 to} the absorption intensity is 0.07 or more. Composition. 5. m- and / or p-isopropenyl-
1 to 20% by weight of α, α'-dimethylbenzyl isocyanate, 0.1 to 5% by weight of a monomer containing a carboxyl group and / or an amide group, and other vinyl monomer having no active hydrogen 98.9 to 75 Claims 1 and 2 obtained by emulsion polymerization of a monomer mixture consisting of wt% in the presence of water, an emulsifier, a tertiary amine compound, and a redox polymerization initiator at a pH of 6 to 8 and at a temperature of 70 ° C or lower. Described
Nyl copolymer aqueous dispersion (A) is compatible with (A).
Containing a hydroxyl group with a gel fraction of 30 to 90% by weight
The vinyl copolymer aqueous dispersion (B) is used as (B) / (A)
The mixing ratio of 1 to 1 equivalent of isocyanate group is
The method for producing a room temperature crosslinkable copolymer aqueous dispersion composition according to any one of claims 1 to 4, wherein the amount of the radical group is 0.1 to 1.2 equivalents .