JPH1046099A - Low pollution type emulsion for single layer elastic coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an emulsion low in rain drop pollutivity and large in initial water resistance. SOLUTION: 95-30 pts.wt. of a 1-12C acryl group-containing (meth)acrylic acid alkyl ester, 5-70 pts.wt. of styrene, 0.5-10.0 pts.wt. of an unsaturated carboxylic acid, and 0.5-10.0 pts.wt. of an amide group-containing acrylic monomer and emulsion-copolymerized in the presence of a polymerizable anionic surfactant and a polymerizable nonionic surfactant in a total amount of 0.5-10.0wt.% based on the whole monomer amount to obtain the low pollution type emulsion used for single layer elastic coating materials and having a glass transition point of -20 to 30 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin emulsion serving as a binder for a single-layer elastic paint, and a single-layer single-layer elastic paint film using this emulsion has good resistance to raindrop contamination and water resistance at the beginning of drying. Also excellent in nature.

[0002]

2. Description of the Related Art Single-layer elastic paints are often used in repainting of lysine or the like in order to provide a single-layer finish with crack followability and high gloss. However, there is a drawback that the coating film is soft and tacky due to the ability to follow cracks and thus easily stained. For this reason, attempts are being made to reduce tackiness by hardening a coating film while sacrificing crack followability and suppressing tackiness. When the coating film is hardened, the contamination of the entire coating film is reduced to some extent. However, this method cannot reduce “raindrop contamination” generated at places where rainwater easily flows down. This "rainfall pollution" is a problem that the difference between the stains on the part with the raindrop and the part without the raindrop is very clear, and the appearance of the building is impaired. Various attempts have been made to reduce raindrop contamination, see Techno-Cosmos 1992, Sep V.
ol. 2 (P.80-84), Polymer Vol. 44, May 1995 (p-307), Building Finishing Technology October 1993 (P74-77), Building Finishing Technology January 1995 (P49-52). For example, studies have been made on hydrophilizing the surface of a coating film and blending with an aqueous polymer. However, if the hydrophilicity of the coating film becomes too high, the water resistance that the single-layer elastic paint should have, especially the water resistance in the early stage of drying, is reduced, and the coating film flows out or blisters due to rainfall after construction. Problems arise.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an emulsion for a single-layer elastic paint which is hardly contaminated by raindrops and has sufficient initial water resistance such that a coating film does not flow out and does not swell due to rainfall after construction. Specifically, it is an object of the present invention to provide an emulsion for a coating material which has both high hydrophilicity of a coating film and water resistance at the initial stage of drying, and has high gloss, elongation, strength and adhesion.

[0004]

According to the present invention, an acrylic monomer having an amide group is used to impart hydrophilicity, and a polymerizable anionic surfactant is used as an emulsifier to improve the water resistance in the initial stage of drying. Combined with a nonionic surfactant,
The problem was solved and the present invention was completed by specifying the amount of use. The present invention relates to "1. alkyl group-containing (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms 95 to 30 parts by weight styrene 5 to 70 parts by weight unsaturated carboxylic acid 0.5 to 10.0 parts by weight amide group containing 0.5 to 10.0% by weight based on the total amount of the acrylic monomer of 0.5 to 10.0 parts by weight, both interfaces of a polymerizable anionic surfactant and a polymerizable nonionic surfactant 1. An emulsion for a low-contamination single-layer elastic paint having a glass transition point of −20 to 30 ° C. obtained by emulsion polymerization using an activator 2. An alkyl group-containing (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms is represented by ( (Meth) methyl acrylate,
2. The emulsion for a low-contamination single-layer elastic paint according to item 1, which is one or more selected from butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. 3. Item 1 or Item 2, wherein the amide group-containing acrylic monomer is acrylamide and / or methacrylamide.
The emulsion for a low-contamination type single-layer elastic paint according to the above item. 4. Item 4. The comonomer according to any one of Items 1 to 3, wherein the hydroxyl group-containing unsaturated monomer, alkoxysilyl group-containing unsaturated monomer, glycidyl group-containing unsaturated monomer, acetoacetyl group An emulsion for a low-contamination type single-layer elastic paint which is copolymerized by adding one or more of unsaturated monomers contained therein. About.

The alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms used in the present invention includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Examples thereof include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and lauryl (meth) acrylate. Those obtained by copolymerizing a (meth) acrylic acid ester containing an alkyl group having 1 to 12 carbon atoms are preferable for controlling weather resistance, water resistance and glass transition point to adjust the coating film hardness, 1) One or more of methyl acrylate, butyl (meth) acrylate, and 2-ethylhexyl acrylate are preferred. The amount used is 95 to 30 parts by weight. If the amount is less than 30 parts by weight, the weather resistance is insufficient and the glass transition point cannot be adjusted to a desired temperature. If the amount is more than 95 parts by weight, it becomes difficult to adjust the gloss. The styrene used in the present invention is used for improving the gloss and adjusting the glass transition point. Styrene is also advantageous for reducing the raw material cost of the emulsion. The amount used is 5 to 70 parts by weight.
If the amount is less than 5 parts by weight, the gloss is insufficient, and if the amount is more than 70 parts by weight, the weather resistance is reduced and the elongation of the coating film is also reduced.

The unsaturated carboxylic acid used in the present invention is used to stabilize the emulsion particles by ionizing on the alkali side to form an electric double layer. For example, acrylic acid, methacrylic acid, maleic acid, crotonic acid, And itaconic acid. The amount used is 0.5-10.0
If the amount is less than 0.5 parts by weight, the particles become unstable, and if it is more than 10.0 parts by weight, the water resistance becomes poor.

The amide group-containing acrylic monomer used in the present invention is used to make the surface of the coating film hydrophilic. The inventor of the present invention has studied various monomers containing a hydrophilic group by copolymerization. Among those which have improved raindrop stain resistance and do not adversely affect the water resistance in the initial stage of drying, amide group-containing (meth) acrylic acid is preferred. Esters were the best. Specific examples include acrylamide, methacrylamide, N-methylol (meth) acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, Nt-butylacrylamide, Nn-butoxymethylacrylamide, and the like. Preferred are acrylamide and methacrylamide. The amount used is 0.5 to 10.0 parts by weight. Preferably it is 1.5 to 6.0 parts by weight.

[0008] In addition to these monomers, copolymerizable monomers can be used. For example, hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl acrylate, 2-hydroxymethyl acrylate, and hydroxypropyl (meth) acrylate used for adjusting hydrophilicity, cross-linking inside particles, and hydrophilicity, Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ for improving alkali resistance -An unsaturated monomer containing an alkoxysilyl group such as acryloxypropyltrimethoxysilane, an unsaturated monomer containing a glycidyl group such as glycidyl (meth) acrylate, acetoacetoxyethyl (meth)
Functional monomers such as acetoacetyl group-containing unsaturated monomers such as acrylate and allyl acetoacetate, as well as ethylene, vinyl acetate, vinyl chloride, and vinylidene chloride can also be used. Also, divinyl benzene, diallyl phthalate, triallyl isocyanurate, tetraallyloxyethane, diallyl terephthalate having two or more polymerizable unsaturated bonds, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (Meth) acrylate, methoxypolyethylene glycol di (meth) acrylate, methoxypolypropylene glycol di (meth) acrylate, and the like can also be used.

These monomers are copolymerized to obtain an emulsion polymer, and the glass transition point of the polymer must be -20 to 25 ° C. The glass transition point of the polymer greatly affects the elongation and stainability of the coating film. If the temperature is higher than 25 ° C., the elongation of the coating film is small, and the crack followability as an elastic paint is lacking. If the temperature is lower than −20 ° C., the tackiness of the coating film becomes strong, and dirt is easily adsorbed, which is not preferable. Although this glass transition point can be measured from an emulsion film,
It can be calculated by the following equation. The glass transition point specified in the present invention is calculated. formula

[0010]

(Equation 1)

W ₁ + W ₂ + W ₃ +... + W _n = 1 Tg ₁ , Tg ₂ , Tg ₃ , and Tgn are glass transition points (absolute temperatures) of each homopolymer.

Next, the polymerizable anionic and nonionic surfactants used in the present invention will be described. These act as emulsifiers in emulsion polymerization, and those having a polymerizable double bond as a polymerizable group in the structure are used. Due to the presence of this polymerizable double bond,
Reduces the water resistance of the coating film because there is no free emulsifier that is not adsorbed on the particle surface when a normal surfactant is used, because it is strongly bonded to the particle surface due to chemical bonding with other monomers There is nothing to do. Further, the present invention is characterized in that anionic and nonionic polymerizable surfactants are used in combination. This is for satisfying polymerization stability and paint suitability while maintaining high water resistance.

The amount of the polymerizable anionic surfactant and nonionic surfactant used is 0.5 to 0.5% based on all monomers.
10.0% by weight is suitable. If the amount is less than 0.5% by weight, the emulsifier in the reaction system becomes insufficient and a good emulsion cannot be obtained. If the content is more than 10.0% by weight, the amount of the unreacted emulsifier increases, and the water resistance decreases. In particular,

[0014]

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R ¹ , R ² : H, CH ₃ , R ³ : _C7-21 alkyl, alkenyl group, M: alkali metal, ammonium group,

[0016]

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R: H, CH ₃ , M: alkali metal, ammonium group, amine,

[0018]

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R: H, CH ₃ , A: alkylene group, n: integer of 2 or more, M: monovalent, divalent cation,

[0020]

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R ¹ : H, CH ₃ , R ² : unsubstituted or substituted hydrocarbon group, etc. A: C _2-4 alkylene group, substituted alkylene group, n: 0, positive number,

[0022]

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R ¹ : H, CH ₃ , R ² : amino group such as unsubstituted or substituted hydrocarbon group, A: C _2-4 alkylene group, n: 0-100 M: monovalent, divalent positive ion,

[0024]

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R ¹ : alkyl group of C _6-18 , R ² : H, alkyl group of C _6-18 , R ³ : H, propenyl group, A: alkylene group of C2-4, substituted alkylene group, M: alkali metal, etc., n: 1 to 200,

[0026]

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R ¹ : H, CH ₃ , R ² : C _8-24 hydrocarbon group, etc. A: C _2-4 alkylene group, M: H, alkali metal, alkaline earth metal, etc. L: 0 -20, m: 0-50,

[0028]

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R: _C8-32 hydrocarbon group, M: alkali metal, ammonium group,

[0030]

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R: C _8-22 hydrocarbon group, M: alkali metal, ammonium group,

[0032]

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R: alkyl, alkylphenyl, A: ethylene, M: ammonium, amine, alkali metal, m: 9, 12, 14, 28

[0034]

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R ¹ : H, CH ₃ , R ² : H, CH ₃ , —C ₆ H ₄ — (CH ₂ ) _m —H, n: 4 to 30

[0036]

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R ¹ , R ² : H, CH ₃ , x: 0 to 100, y: 0 to 10 z: 0 to 100, 1 ≦ x + y + z ≦ 100,

[0038]

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R ¹ : C _6-18 alkyl group, etc. R ² : H, C _6-18 alkyl group, etc. R ³ : H, propenyl group, A: C _2-4 alkylene group, substituted alkylene group , N: 1 to 200,

[0040]

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R ¹ : H, CH ₃ , R ² : C _8-24 hydrocarbon group, acyl group, A: C _2-4 alkylene group, L: 0-100, m: 0-50,

[0042]

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R ¹ , R ² : H, C _1-36 hydrocarbon group, acyl group, A ¹ , A ² : C _2-4 alkylene group, substituted alkylene group, L: 1, 2, m, n 0, a positive number, m + n ≧ 3, and a reactive nonionic surfactant such as m, n ≧ 1 when both R ¹ and R ² are H.

In addition, a non-reactive surfactant can be used in combination to improve the stability of the emulsion. However, since the water resistance is reduced, the amount is limited. Non-reactive emulsifiers include anionic surfactants such as alkyl or alkyl allyl sulfate, alkyl or alkyl allyl sulfonate, dialkyl sulfosuccinate, and cationic surfactants such as alkyltrimethylammonium chloride and alkylbenzylammonium chloride And nonionic surfactants such as polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether and polyoxyethylene carboxylate.

As the radical initiator in the polymerization, any one can be used as long as it is used in a usual emulsion polymerization. Persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide and the like can be used. Oxides,
Water-soluble types such as azobisamidinopropane hydrochloride,
Examples thereof include oil-soluble types such as benzoyl peroxide, cumene hydroperoxide, dibutyl peroxide, diisopropyl peroxide, cumyl peroxy neodecanoate, cumyl peroxy octoate, and azobisisobutinitrile. Further, a redox system in which a reducing agent such as sodium acid sulfite, Rongalit, or ascorbic acid is used as an initiator can also be used.

The polymerization may be a usual emulsion polymerization. A batch system in which all the monomers are charged into a reaction vessel at once, a drop system in which the monomers are dropped at any time during the reaction, and a monomer system in which the monomers, water and A method in which an emulsifier is emulsified in advance and dropped as a monomer emulsion can be used. If desired, a chain transfer agent used for adjusting the degree of polymerization for improving gloss, a film-forming aid for adjusting the minimum film-forming temperature, a plasticizer for improving the flexibility of the coating film, a thickener, a defoamer, and a preservative. Additives such as agents and antifreezing agents can be used.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION The emulsion of the present invention is prepared by emulsifying and dispersing a monomer and water with a surfactant in advance to prepare a monomer emulsion, and then adding water and a surfactant to a reaction vessel heated and heated. The resulting emulsion is obtained by dropping the prepared monomer emulsion, appropriately adding an initiator, and performing emulsion polymerization.

[0048]

【Example】

Example 1 In a reactor, 445 parts by weight of water, 2.5 parts by weight of sodium acetate, 1 part by weight of an anionic polymerizable surfactant, 8 parts by weight of a nonionic polymerizable surfactant, 2.5 parts by weight of an anionic surfactant 484 parts by weight of water, 14 parts by weight of anionic polymerizable surfactant, 9.5 parts by weight of nonionic polymerizable surfactant, 8.5 parts by weight of anionic surfactant, 423 parts by weight of styrene. 417 parts by weight of 2-ethylhexyl acrylate, 217 parts by weight of methyl methacrylate,
A mixture obtained by emulsifying and mixing 24.5 parts by weight of an 80% aqueous solution of acrylic acid and 28.5 parts by weight of methacrylamide was added dropwise. The temperature was controlled at 80 ° C., and 61.5 parts by weight of 5% ammonium persulfate was added dropwise to the initiator. Emulsion polymerization. After completion of the polymerization, the mixture was neutralized with aqueous ammonia to obtain an emulsion having a nonvolatile content of 50%. Calculated Tg of the resulting emulsion
Was 11.5 ° C.

Examples 2 to 9 Based on the polymerization compositions shown in Table 1, other emulsions were obtained in the same manner as in Example 1.

[0050]

[Table 1]

Comparative Example 1 (Example in which no amide group-containing acrylic monomer was used) Based on the polymerization composition shown in Table 2, other emulsions were obtained in the same manner as in Example 1.

Comparative Example 2 (Example in which no polymerization emulsifier was used) Based on the polymerization composition shown in Table 2, other emulsions were obtained in the same manner as in Example 1.

Comparative Example 3 (Example in which an amide group-containing acrylic monomer was used in an undersized amount) Based on the polymerization composition shown in Table 2, other emulsions were obtained in the same manner as in Example 1.

Comparative Example 4 (Example in which an amide group-containing acrylic monomer was used in excess) Based on the polymerization composition shown in Table 2, other emulsions were obtained in the same manner as in Example 1.

[0055]

[Table 2]

Evaluation (Preparation of Paint) A single-layer elastic paint was prepared according to the following paint formulation. Water 74 parts by weight Ethylene glycol 14 parts by weight Pigment dispersant 9.2 parts by weight Preservative 2 parts by weight Antifoam 1 part by weight Titanium oxide 93 parts by weight Calcium carbonate 93 parts by weight This is ground by a sand mill to obtain a pigment paste. . Next, emulsion 565 parts by weight 14% ammonia water 5.5 parts by weight Butyl cellosolve / water (1/2) 84 parts by weight Texanol 44 parts by weight Defoamer 2 parts by weight Acrylic acid-based thickener aqueous solution 28 parts by weight Urethane-based increase Twenty-four parts by weight of the aqueous solution of the viscosity was added and stirred. (Evaluation test) (1) Dry initial water resistance A slate plate coated with a solvent-based chlorinated polyolefin sealer is coated with a coating of 2 mm thickness (wet), dried for 24 hours at room temperature, and immersed in water for 24 hours to be coated. Check for spills and blisters. There is coating film bleeding and blistering ..... × No coating film bleeding and no blistering .............. (2) Raindrop contamination resistance Paint is applied to a slate plate coated with an emulsion type acrylic sealer. It is applied twice with a roller to form an average 2 mm thick (wet) pattern. Dry at room temperature for one week and place in an outdoor raindrop tester. (Raindrop tester: A plastic corrugated plate is placed on top of the slate plate so that raindrops are likely to occur.
It is installed diagonally on the top, and in the event of rain, rain falls on the slate plate from the valley of the corrugated plate. ) Obviously, raindrop contamination was observed .... × Almost no raindrop contamination was observed. Table 3 shows the evaluation results.

[0057]

[Table 3]

[0058]

EFFECTS OF THE INVENTION The emulsion of the present invention has an extremely low raindrop contaminating property, and has an excellent effect of having high initial water resistance such that the coating does not cause blistering or runoff due to rainfall after construction.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08F 220/10 MLY C08F 220/10 MLY (C08F 220/10 212: 08 220: 04 220: 56)

Claims (4)

[Claims] An alkyl group-containing (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms 95 to 30 parts by weight Styrene 5 to 70 parts by weight Unsaturated carboxylic acid 0.5 to 10.0 parts by weight Amide group-containing acrylic type 0.5 to 10.0% by weight, based on the total monomer consisting of 0.5 to 10.0 parts by weight, of both the polymerizable anionic surfactant and the polymerizable nonionic surfactant A low-contamination type emulsion for a single-layer elastic paint having a glass transition point of -20 to 30 ° C., obtained by emulsion polymerization using 2. An alkyl group-containing (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms selected from methyl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. The emulsion for a low-contamination type single-layer elastic paint according to claim 1, which is described above. 3. The emulsion according to claim 1, wherein the amide group-containing acrylic monomer is acrylamide and / or methacrylamide. 4. The comonomer according to claim 1, wherein the monomer is a hydroxyl group-containing unsaturated monomer, an alkoxysilyl group-containing unsaturated monomer, or a glycidyl group-containing unsaturated monomer. An emulsion for a low-contamination single-layer elastic paint, which is obtained by adding one or more of an unsaturated monomer having an acetoacetyl group and a copolymer.