JPH11279235A - Resin composition for water-based coating material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having water-based one-pack form, storable for a long period and extremely quickly dryable in coating by radically polymerizing an ethylenic unsaturated monomer under specific pH condition. SOLUTION: Radical polymerization of (A) a radically polymerizable ethylenic unsaturated monomer (hereunder called as unsaturated monomer), (B) a carboxyl-containing unsaturated monomer (preferably acrylic acid, or the like) and (C) a compound having radically polymerizable unsaturated double bond and expressed by formula I or II (R is OCH3 or OC2 H5 ) (e.g. γ- methacryloxypropylmethyldimethoxysilane) is started in the presence of an emulsifier, a polymerization initiator and water. The amounts of the component B and the component C are 0.1-10 wt.% and 0.1-20 wt.% based on 100 pts.wt. of the total unsaturated monomer. The polymerization is carried out by adjusting the pH of the dropping component to >=6 before the start of polymerization by preparatorily adding a volatile base (preferably ammonia) to the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for paints and a method for producing the same, and more particularly to an aqueous one-pack type which can be stored for a long time and has a very fast drying property when applied. The present invention relates to a resin composition and a method for producing the same. The composition of the present invention may be used for paints, synthetic resins, metals, glass, ceramics, gypsum, paper, wood, leather, and even lightweight concrete, mortar, calcium silicate board, slates, or gypsum boards. Can be applied to various substrates,
Form a good coating film such as water repellency, water resistance, weather resistance, stain resistance, adhesion, and chemical resistance.

[0002]

2. Description of the Related Art In recent years, organic solvent-based paints are being replaced with water-based paints, especially water-based emulsion paints, for reasons such as resource problems and workability safety. However, ordinary water-based emulsion-type paints are inferior to organic solvent-type paints in that the emulsion-polymerized resin dispersed in water is fused during drying to form a film, and the water-based emulsion-type resin is water-based. The film had a drawback that the drying properties of the film were slow and the physical properties of the coating film such as water resistance were poor. In order to improve this drawback, it is known that the particle size of the emulsion polymerization resin is made very fine to improve the denseness of the coating film and to improve the water resistance. There was a problem that the water flowed out due to rain immediately after.

As a method for improving the water resistance and water repellency of a film, there is known a means for copolymerizing a hydrolyzable silane compound having a radically polymerizable double bond in the same molecular structure. In order to obtain the product, a silane compound having a double bond capable of radical polymerization and an ethylenically unsaturated monomer are once synthesized by solution polymerization, and then the solution is removed by stripping and further dispersed in water. Is the way. In this method, there is a problem that the working process becomes very long and the cost becomes high. In addition, there is a method of emulsion polymerization using a buffer, but this method can certainly obtain an intended product, but there is a disadvantage that the water resistance and the like in the coating film properties are inferior due to the mixing of the buffer. .

[0004]

SUMMARY OF THE INVENTION As a result of intensive studies, the present inventors have found that a coating composition and a method for producing the same can be stored for a long time in one aqueous solution and have an extremely fast drying property when applied. And a method for producing the same. In the present invention, "fast drying property" means that a coating film formed does not flow out even if it is brought into contact with water after a lapse of 30 minutes after application to a substrate under conditions of a temperature of 5 ° C. and a humidity of 65%. It is.

[0005]

Means for Solving the Problems The first invention comprises (a) a radically polymerizable ethylenically unsaturated monomer and (b) a radically polymerizable ethylenically unsaturated monomer having a carboxyl group. The monomer is used in an amount of 0.1 to 10% by weight based on 100 parts by weight of the radically polymerizable ethylenically unsaturated monomer, and further has (c) a radically polymerizable unsaturated double bond in the molecule. An emulsifier comprising a compound represented by the general formula (1) in an amount of 0.1 to 20% by weight based on 100 parts by weight of a radically polymerizable ethylenically unsaturated monomer;
When radical polymerization is initiated by using a polymerization initiator and water as essential components, a volatile base is allowed to coexist in advance, so that the polymerization is carried out under conditions where the pH of the dropped portion before the polymerization is started is 6.0 or more. Water-based paint resin composition. General formula (1)

[0006]

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[0007] A second invention is a resin composition for an aqueous paint according to the first invention, wherein the volatile base is ammonia.
The third invention is a reactive emulsifier having a radically polymerizable unsaturated double bond in the molecule as the emulsifier of the first invention, and comprises a radically polymerizable ethylenically unsaturated monomer 10
A water-based coating resin composition characterized by being used in an amount of 0.1 to 10% by weight based on 0 part by weight. The fourth invention is characterized in that a monomer having a carboxyl group among (a) a radically polymerizable ethylenically unsaturated monomer and (b) a radically polymerizable ethylenically unsaturated monomer can be radically polymerized. 0.1 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer.
1 to 10% by weight, and further (c) a compound represented by the general formula (1) having a radically polymerizable unsaturated double bond in the molecule is obtained by subjecting all radically polymerizable ethylenically unsaturated monomers to 100 When the radical polymerization is started by using 0.1 to 20% by weight based on the weight part of the emulsion as an essential component of an emulsifier, a polymerization initiator and water, a volatile base is allowed to coexist in advance, so that a dropping amount before the start is obtained. Is a method for producing a resin composition for water-based coatings, wherein the polymerization is carried out under conditions where the pH is 6.0 or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The (a) radically polymerizable ethylenically unsaturated monomer used in the present invention is a monomer composed of an alkyl ester of (meth) acrylic acid, and is a monomer of methyl acrylate or acrylic acid. Ethyl, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, stearyl methacrylate,
(Meth) acrylates such as cyclohexyl methacrylate, styrene, alpha methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate and the like can be used.

(B) Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc. as monomers having a carboxyl group improve the stability during production or storage of the resin composition for water-based paints. Therefore, it is preferable to use them together. For this purpose, it is preferable to use a monomer having a carboxyl group in an amount of 0.5 to 5 parts by weight based on the total amount of radically polymerizable ethylenically unsaturated monomers. 0.5
If the amount is less than 5 parts by weight, the polymerization stability and the viscosity stability with the lapse of time are poor. If the amount is more than 5 parts by weight, the water resistance of the obtained coating film is poor. The compound (c) represented by the general formula (1) having a radically polymerizable unsaturated double bond in the molecule used in the present invention has a hydrolyzable reactive group. It is known that the pH proceeds under acidic conditions of 2 to 4. As the component (c), there are γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and the like. One or more of these may be used in combination. These are preferably used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the total radical polymerizable ethylenically unsaturated monomer.
More preferably, it is used in an amount of 0.5 to 10 parts by weight. When the amount is less than 0.1 part by weight, the effect of drying property of the coating film is not observed, and the obtained coating film has poor water resistance. If the amount is more than 20 parts by weight, cracks or the like are generated in the coating film. A volatile base is used in order to make the pH of the dropping amount before the start of the polymerization neutral or alkaline at 6.0 or more. The volatile base used includes, but is not limited to, ammonia, trimethylamine, triethylamine, butylamine, 2-dimethylaminoethanol, monophorin, N-methylmonophorin, ethylenediamine, and mixtures thereof. Preferably, ammonia is recommended from the viewpoint of volatility and safety.

The amount of the volatile base used in the present invention is:
The component (c) does not undergo a hydrolysis reaction during radical polymerization or during long-term storage as a paint. That is, it is selected in consideration of the pH of the resin composition for water-based paint being 6.0 or more. More preferably, it is used so that the pH becomes 6.5 to 9.0. If the pH is lower than this, the component (c) is hydrolyzed, and not only does the drying effect of the paint disappear, but also gelation occurs during long-term storage. On the other hand, if the pH is too high, the effect of the drying property is reduced and the physical properties of the obtained coating film are adversely affected. The emulsifier used in the present invention is an anionic or nonionic reactive emulsifier having one or more radically polymerizable unsaturated double bonds in the molecule, and is, for example, a sulfosuccinate type (as a commercially available product, for example, Kao Latemul S-120 manufactured by Co., Ltd.
P, S-180A, Sanyo Kasei Co., Ltd. Eleminor JS
-2 etc.), alkylphenol ethers (commercially available from Dai-ichi Kogyo Seiyaku Co., Ltd., Aqualon HS-10, R
N-20). In emulsion polymerization, these 1
Seeds or a mixture of two or more kinds is used.

These emulsifiers are preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the radically polymerizable ethylenically unsaturated monomer. When the amount is more than 10 parts by weight, the particle size becomes small, but since a large amount of emulsifier is used, the water resistance of the coating film is deteriorated as an adverse effect. Further, when these emulsifiers have no reactivity, even if a stable resin dispersion is obtained, a decrease in water resistance due to elution of the activator is inevitable. As the polymerization initiator in the radical polymerization of the present invention, radical polymerization can be performed by heat or a reducing substance to cause addition polymerization of an ethylenically unsaturated monomer, and a water-soluble or oil-soluble persulfate, Peroxides, azo compounds and the like can be effectively used. Examples thereof include ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride,
2,2-azobis (2,4-dimethylvaleronitrile)
And the like. As the amount of the polymerization initiator,
0.1 to 5% by weight is used based on 100 parts by weight of the total radical polymerizable ethylenically unsaturated monomer.

In the present invention, copper ions such as cupric sulfate and cupric chloride, and transition metal ions such as ferric sulfate and ferric chloride are added to the water charged in the reaction vessel in an amount of 10 ⁻⁷ to 10 ^−. It is desirable to add in the range of ⁵ mol / liter. The resin composition for water-based paint obtained according to the present invention can contain a coloring agent such as a dye or a pigment, a filler, etc., and can be made of synthetic resin, metal, glass, ceramics, gypsum, paper, wood, leather, and even lighter. Use as a topcoat paint, paint binder, paper processing agent, fiber treatment agent, etc. for concrete, lightweight foam concrete, mortar, calcium silicate board, slates, gypsum boards, etc. Can be. In producing the water-based paint of the present invention, a pigment, a pigment dispersant, a colorant, a thickener, an aggregate, an antifoaming agent, a plasticizer, a film-forming auxiliary, an organic solvent, a preservative, a fungicide, A regulator and the like can be selected for various purposes and used in the present invention in a usual manner by a combination.

[0013]

The present invention will be described below with reference to examples. The present invention is not limited by these.
In the examples, “parts” means “parts by weight” and “%” means “% by weight”. Example 1 A reactor equipped with a stirrer, a thermometer, a dropping funnel and a reflux reactor was charged with the amount of the reactor shown in Table 1, and saturated with nitrogen gas. Ammonia water is added in advance to the drops in Table 1, and the pH of the drops before the start of polymerization is adjusted to 6.0. After the internal temperature was raised to 80 ° C., dropping was started. The dropping amount was dropped in 2 hours, aged at 80 ° C. for further 2 hours, and cooled, and the solid content was 51.0%, viscosity was 400 cps, pH was
A resin composition for aqueous coating compositions of 6.8 was obtained.

[0014]

[Table 1]

Examples 2 to 4 The compositions shown in Table 2 were polymerized in the same manner as in Example 1 to obtain respective water-based paint resin compositions.

[0016]

[Table 2]

Comparative Examples 1-4 Polymerization under acidic conditions at the pH of the dropping amount before the initiation of polymerization, polymerization without the carboxyl group monomer, and polymerization using a non-reactive surfactant Each of the polymer and the polymer obtained by removing the component (c) was produced in the same manner as in Example 1 as Comparative Examples 1 to 4. The composition is shown in Table 3.

[0018]

[Table 3]

Further, paints were prepared according to the paint formulation shown in Table 4 using the obtained water-based paint resin compositions of Examples 1 to 4 and Comparative Examples 1 to 4.

[0020]

[Table 4]

All paints were adjusted to pH 9.0 with 25% aqueous ammonia. Furthermore, the polymerization stability of the aqueous paint resin composition obtained by polymerization,
The storage stability and the water-whitening resistance, alkali resistance, and quick-drying properties of the coating films after coating them were evaluated. The results were as shown in Table 5. Evaluation of Properties and Film Properties of Resin Composition for Aqueous Paint (1) Polymerization Stability: The amount of resin adhered to a reaction vessel after completion of the reaction and the amount of agglomerates after filtration with a filter cloth were visually evaluated. . The evaluation criteria are as follows.

A: Good. ：: This is a practically acceptable level. ×: Poor. (2) Storage stability: The resin composition for water-based paint was placed in a closed glass container, stored at 40 ° C. for one month, and the rate of change in viscosity was measured. Further, the aggregate at the bottom of the glass container was visually evaluated. The evaluation criteria are as follows. A: Viscosity change rate ≤ ± 10%, no agglomerate observed. ：: Viscosity change rate ≦ ± 10%, and slight aggregation is observed.

Δ: Viscosity change rate ± 10% to ± 30%, or some aggregates are observed. ×: Change in viscosity ≧ 30% or considerable sediment is observed. (3) Water whitening resistance: The coating material prepared above was applied to a glass plate with a 5 mil applicator, dried at room temperature for 7 days, and the obtained coating film was immersed in 50 ° C. warm water for 1 hour. The degree of whitening was visually evaluated. In addition, evaluation was performed by five-point evaluation. 5 points: No whitening. 1 point: Significant whitening is observed on the entire surface. (4) Alkali resistance: The coating material prepared above was applied on a glass plate with a 5 mil applicator, dried at room temperature for 7 days, and the resulting coating film was immersed in a saturated aqueous solution of calcium hydroxide for 7 days. The change was evaluated visually.

5 points: No change at all. 1 point: Significant peeling, whitening, swelling, etc. of the coating film are observed on the entire surface. (5) Quick drying: 5 m of the paint prepared above on a glass plate
Apply with il applicator, temperature 5 ℃, humidity 65%
Drying is performed under the following conditions. Water was contacted at intervals of 5 minutes, and the evaluation was made based on the time when the paint stopped flowing.

[0025]

[Table 5]

[0026]

According to the present invention, one aqueous solution has good polymerization stability, coating film properties and storage stability.
Under a condition of 5%, a resin composition for a coating can be obtained which has an extremely fast drying property in which a formed coating film does not flow out even if it is brought into contact with water after 30 minutes from the application to a substrate. .

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Claims (4)

[Claims] 1. An ethylene capable of radical polymerization of (a) a radically polymerizable ethylenically unsaturated monomer and (b) a radically polymerizable ethylenically unsaturated monomer having a carboxyl group. 0.1 to 10% by weight based on 100 parts by weight of the unsaturated monomer, and (c) a general formula (1) having a radically polymerizable unsaturated double bond in the molecule.
The compound represented by the formula (1) is used in an amount of 0.1 to 20% by weight based on 100 parts of the radically polymerizable ethylenically unsaturated monomer, and radical polymerization is initiated using an emulsifier, a polymerization initiator and water as essential components. In this case, by allowing a volatile base to coexist in advance, the pH of the dropped portion before the start of polymerization is adjusted to 6.
A resin composition for water-based paint, which is polymerized under 0 or more conditions. General formula (1) 2. The resin composition according to claim 1, wherein the volatile base is ammonia. 3. A reactive emulsifier having a radically polymerizable unsaturated double bond in the molecule as an emulsifier, and is used in an amount of 0.1 to 100 parts by weight based on 100 parts by weight of all radically polymerizable ethylenically unsaturated monomers. The resin composition for a water-based paint according to claim 1, wherein the resin composition is used in an amount of 10% by weight. 4. An ethylene capable of radical polymerization of (a) a radically polymerizable ethylenically unsaturated monomer and (b) a radically polymerizable ethylenically unsaturated monomer. 0.1 to 10% by weight based on 100 parts by weight of the unsaturated monomer, and (c) a general formula (1) having a radically polymerizable unsaturated double bond in the molecule.
The compound represented by the formula (1) is used in an amount of 0.1 to 20% by weight based on 100 parts of the radically polymerizable ethylenically unsaturated monomer, and radical polymerization is initiated using an emulsifier, a polymerization initiator and water as essential components. In this case, by allowing a volatile base to coexist in advance, the pH of the dropped portion before the start of polymerization is adjusted to 6.
A method for producing a resin composition for a water-based coating, comprising polymerizing under 0 or more conditions. General formula (1)