JP2008208152A - Aqueous resin emulsion for plastic coating agent and plastic coating agent produced by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous resin emulsion useful for designing a plastic coating agent having excellent adhesiveness, water-resistance, etc., and to provide a plastic coating agent produced by using the emulsion. <P>SOLUTION: The aqueous resin emulsion is produced by the radical polymerization of an ethylenic unsaturated monomer such as an acrylic acid ester in the presence of a water-soluble or water-dispersible polyester resin having a carboxyl group and a crosslinking agent for the polyester resin. The invention further provides a plastic coating agent produced by using the resin emulsion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aqueous emulsion obtained by polymerizing an ethylenically unsaturated monomer such as an acrylate ester in an aqueous medium, and more particularly, an ethylenically unsaturated monomer in the presence of a water-soluble or water-dispersible polyester. The present invention relates to a method for producing an aqueous resin emulsion for a plastic coating agent, which is an aqueous emulsion obtained by polymerizing a body and has excellent performance by polymerization in the presence of a crosslinking agent of a polyester resin.

Conventionally, aqueous resin emulsions obtained by polymerizing ethylenically unsaturated monomers such as acrylate esters in aqueous media, especially acrylate copolymer resin emulsions, are aqueous, so the content of volatile organic compounds Therefore, it is widely used for various coating agents and adhesives because it can reduce the burden on the environment.
In addition, this water-based resin emulsion has characteristics of adhering to various base materials and is excellent in durability, so it is used for various coating agents, primers, etc. On the other hand, a resin base material different from acrylic resin, for example, Polyester resins such as PET are insufficiently bonded with ordinary acrylic resin emulsions and cannot be used as coating agents or primers in many cases.

In order to remedy this drawback, Patent Document 1 is obtained by polymerizing monomers using an anionic emulsifier alone or a combination of an anionic emulsifier and a nonionic emulsifier in the presence of a polyester resin having a hydrophilic group. An aqueous resin composition having an average particle size of 50 to 200 nanometers is shown. If this aqueous resin emulsion is used, it is possible to obtain excellent adhesion to a polyester base material compared to a normal acrylic resin emulsion, but the molecular weight of the coexisting polyester resin is at most about tens of thousands. And there was a drawback of poor durability.
Japanese Patent No. 3353435

  An object of the present invention is to develop an acrylic ester copolymer aqueous resin emulsion having good adhesion to a plastic substrate and excellent in durability, and a plastic coating agent using the same.

As a result of intensive studies on the above-mentioned problems, the present inventors have conducted radical polymerization of an ethylenically unsaturated monomer in the presence of a water-soluble or water-dispersible polyester in the presence of a crosslinking agent for a polyester resin. By conducting the polymerization, the inventors have found that the adhesiveness to the plastic substrate is excellent and the durability is excellent, and the present invention has been completed.
That is, this invention consists of the following.
(1) Ethylenic unsaturation in the presence of a water-soluble or water-dispersible polyester resin (a) having a carboxyl group and a crosslinking agent (c) having two or more functional groups capable of reacting with the carboxyl group of the polyester resin An aqueous resin emulsion obtained by radical polymerization of the monomer (b).

(2) Polyester resin (a) 2 to 75% by mass
Ethylenically unsaturated monomer (b) 97.8-20% by mass
Cross-linking agent (c) 0.2-5% by mass
And (a)> = (c), (a) + (b) + (c) = 100 mass% is satisfy | filled, The aqueous resin emulsion as described in said (1) characterized by the above-mentioned.
(3) The aqueous resin emulsion as described in (1) or (2) above, wherein the crosslinking agent (c) is a polyfunctional compound having at least two epoxy groups in the molecule.
(4) The aqueous resin emulsion according to any one of (1) to (3) above, which contains an emulsifier.
(5) A plastic coating agent comprising the aqueous emulsion according to any one of (1) to (4) above.

  The aqueous resin emulsion of the present invention is extremely useful as a coating agent because of its excellent adhesion to a plastic substrate and excellent durability.

Hereinafter, the present invention will be described in detail.
The water-soluble or water-dispersible polyester (a) used in the present invention is produced from a polybasic acid and a polyol, and the production method is not limited at all.
Typical examples of the polybasic acid component include terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, adipic acid, succinic acid, sebacic acid, dodecanedioic acid and the like. More than one species may be used in combination.
Typical examples of the polyol component include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, cyclohexane dimethanol, bisphenol, and the like. These may be used alone or in combination of two or more.

Furthermore, in order to impart water solubility or water dispersibility, a component having a hydrophilic group can be copolymerized. As specific examples of these, in order to introduce an organic sulfonate into a polyester molecule, for example, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, etc. Alkali metal salts and ammonium salts are used.
In order to introduce a carboxyl group into the polyester molecule, for example, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, trimesic acid, etc. are used and neutralized with an amino compound, ammonia or alkali metal, etc. Can be introduced into the molecule as a carboxylate group. Neutralization imparts water dispersibility to the polyester resin. Neutralization dissociates the carboxyl group into a carboxylate anion, and contributes to dispersion stabilization in water by imparting solubility and ionic repulsion at the water-resin interface.

When introducing a carboxyl group, it is preferable to adjust the acid value of the polyester resin to be 1 to 100. If the acid value exceeds 100, the adhesion to the plastic substrate and water resistance are poor. If it is less than 1, the amount of carboxyl groups that can react with the epoxy group-containing crosslinking agent is small, and durability such as warm water resistance decreases. It is not preferable.
As the water-soluble or water-dispersible polyester having a carboxyl group used in the present invention, commercially available polyesters may be used as they are. For example, Plus Coat (registered trademark, manufactured by Kyoyo Chemical Industry Co., Ltd.) Z-561, Z -730, RZ-142, Pesresin (registered trademark, manufactured by Takamatsu Yushi Co., Ltd.) A-110, A-210, A-620, Bironal (registered trademark, manufactured by Toyobo Co., Ltd.) MD-1200, MD-1220 MD-1250, MD-1335, MD-1400, MD-1480, MD-1500, and the like.

The amount of the water-soluble or water-dispersible polyester used is preferably 2 to 75% by mass, more preferably 5 to 50% by mass in the composition, and if it is less than 2% by mass, the stability of the resulting aqueous emulsion is lowered. Or the effect of improving the adhesion to the plastic substrate tends to be small. When it exceeds 75 mass%, water resistance tends to be impaired.
In the presence of the water-soluble or water-dispersible polyester containing the carboxyl group and a crosslinking agent for the polyester, an ethylenically unsaturated monomer such as an acrylate ester is radically polymerized.

  Examples of the ethylenically unsaturated monomer (b) used for radical polymerization include (meth) acrylic acid alkyl esters and those having at least one polymerizable (meth) acryloyl group. Specific examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid esters having a linear, branched or cyclic alkyl chain having 1 to 18 carbon atoms (methyl (meth) acrylate, ethyl ( (Meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl ( (Meth) acrylate, isoboronyl (meth) acrylate, etc.).

  In addition, aromatic vinyl compounds (styrene, α-methylstyrene, p-methylstyrene, ethylvinylbenzene, etc.), heterocyclic vinyl compounds (vinylpyrrolidone, etc.), hydroxyalkyl (meth) acrylates (2-hydroxyethyl (meth)) Acrylate, 2-hydroxypropyl (meth) acrylate, etc.), polyalkylene glycol (meth) acrylate (ethylene glycol (meth) acrylate, butylene glycol (meth) acrylate, etc.), alkylamino (meth) acrylate (N, N-dimethyl) Aminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, etc.), vinyl ester compounds (vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, etc.), monoolefin compounds ( Tylene, propylene, butylene, isobutylene, etc.), conjugated diolefin compounds (butadiene, isoprene, chloroprene, etc.), α, β-unsaturated mono- or dicarboxylic acids (acrylic acid, methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid) Acid, maleic anhydride, fumaric acid, etc.),

Carboxyl group-containing vinyl compounds (monohydroxyethyl (meth) acrylate phthalate, monohydroxypropyl (meth) acrylate oxalate, etc.), amineimide group-containing vinyl compounds (1,1,1-trimethylamine methacrylamide, etc.), vinyl cyanide compounds (Acrylonitrile, methacrylonitrile, etc.), amide group or substituted amide group-containing α, β-ethylenically unsaturated compound ((meth) acrylamide, N-methylacrylamide, N, N-dimethyl (meth) acrylamide, N, N- Dimethylaminopropyl (meth) acrylamide, etc.), α, β-ethylenically unsaturated compounds containing carbonyl groups (acrolein, diacetone acrylamide, vinyl methyl ketone, diacetone acrylate, acetonitrile acrylate, etc.), Phosphonic acid group-containing α, β-ethylenically unsaturated compounds (allyl sulfonate, sodium p-styrenesulfonate, etc.), ethylenically unsaturated group-containing ultraviolet absorbers (2- (2′-hydroxy-5′-metaacrylic) Known polymerizable vinyl compounds such as yloxyethylphenyl) -2H-benzotriazole and the like, and ethylenically unsaturated group-containing light stabilizers (1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, etc.) Can be used.

If necessary, as a crosslinkable monomer of the radical copolymer, an epoxy group-containing α, β-ethylenically unsaturated compound (glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether) , Glycidyl (meth) allyl ether, 3,4-epoxycyclohexyl (meth) acrylate, etc.), hydrolyzable alkoxysilyl group-containing α, β-ethylenically unsaturated compounds (vinyltriethoxysilane, vinyltris (β-methoxyethoxy) Silane, γ-methacryloxypropyltrimethoxysilane, etc.), polyfunctional vinyl compounds (ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, divinylbenzene, diallyl phthalate) ), Etc., to cross-link themselves, or in combination with an ethylenically unsaturated compound component having an active hydrogen group, or a carbonyl group-containing α, β-ethylenically unsaturated compound (especially a keto group) And a polyhydrazine compound (especially a compound having two or more hydrazide groups; oxalic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, polyacrylic acid hydrazide, etc.) Is also possible.
The amount of the ethylenically unsaturated monomer (b) used is preferably 97.8 to 20% by mass.

  The crosslinking agent (c) used in the present invention can be used as long as it has two or more functional groups capable of reacting with the carboxyl group of the polyester resin. Preferred is a compound containing at least two epoxy groups (including alicyclic), specifically, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, trimethylpropane polyglycidyl ether, neopentyl glycol glycidyl ether, bisphenol A glycidyl ether Polyfunctional epoxy compounds such as ether are listed, alone or as needed Use to can be used.

The amount of the crosslinking agent (c) that can react with the carboxyl group of the polyester resin is preferably 0.2 to 5% by mass, more preferably 0.5 to 3% by mass, and 0.2% by mass in the composition. If it is less than 5%, the water resistance decreases, and if it exceeds 5% by mass, the adhesion to the plastic substrate is impaired, which is not preferable.
In the synthetic resin aqueous emulsion of the present invention, if necessary, an anionic emulsifier and a nonionic emulsifier may be used in combination, and the type and amount of the emulsifier are the amount of water-soluble or water-dispersible polyester resin used or polymerization. The composition is adjusted according to various conditions including the monomer composition.

  As the emulsifier, both nonionic and anionic properties may be known and used, and typical examples include polyoxyalkylene alkyl ether, polyoxyalkylene alkylphenol ether, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan. Nonionic surfactants such as fatty acid esters, alkyl sulfate esters, alkyl benzene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, polyoxyalkylene alkyl sulfates, polyoxyalkylene alkyl phosphates, and the like A surfactant can be used. Two or more different emulsifiers may be used in combination as the emulsifier. Further, a water-soluble polymer such as polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and polyvinyl pyrrolidone may be used as long as the adhesiveness to the plastic substrate is not impaired.

The polymerization initiator used in the emulsion polymerization may be a known and conventional one, and representative examples include hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, t-butyl hydroperoxide, and the like. If necessary, redox polymerization may be performed by combining with sodium sulfoxylate formaldehyde, ascorbic acid, sulfites, tartaric acid or salts thereof. Moreover, you may use alcohol and mercaptans as a chain transfer agent as needed.
The average particle size of the emulsion particles is not particularly specified, but is preferably 2.0 μm or less in consideration of sedimentation stability. The emulsion particles are considered to form a single particle whose outer shell is polyester and whose inside is acrylic. The average particle size is determined by dynamic light scattering.

  In order to adjust the average particle diameter of the emulsion particles, starting with the amount of water-soluble or water-dispersible polyester used, the method of introducing the polyester, the amount of polymerization initiator, the amount when using an emulsifier described later, etc. You may adjust by. For example, when a large amount of water-soluble or water-dispersible polyester is used, the average particle size of the emulsion obtained tends to be small. Even when the same amount of the polyester is used, the average particle size tends to be smaller in the case where the polymerization is carried out after being introduced into the reactor in comparison with the case where the polymerization is carried out while dropping. When the amount of the polymerization initiator used in the initial stage of polymerization is increased, or when an emulsifier is used in combination, the average particle size tends to decrease.

The synthetic resin aqueous emulsion of the present invention is produced by any one of a batch type, a semi-continuous type and a continuous type using a normal pressure or pressure resistant reactor. The reaction temperature is usually 10 to 100 ° C., but 30 to 90 ° C. is common. The reaction time is not particularly limited, and may be appropriately adjusted according to the amount of each component and the reaction temperature.
The synthetic resin aqueous emulsion thus obtained can be obtained from resin components such as acrylic resins, ethylene-vinyl acetate resins, vinyl acetate resins, epoxy resins, amino resins, urethane resins, isocyanate compounds, etc. Cross-linking agents (post-cross-linking with post-additives for cross-linking acrylic components or polyester and acrylic components), surfactants, viscosity improvers, colorants, anti-blocking agents, antifoaming agents, etc. can be added Furthermore, it is of course possible to paint it using extender pigments and colored pigments and use it as a coating agent.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
The evaluation methods of the aqueous emulsions prepared in the examples and comparative examples were as follows.
(Normal adhesion)
The emulsion obtained in each Example and each Comparative Example was made into a paint with the following composition and the viscosity was adjusted, and then applied to a SMC molded plate (using unsaturated polyester) and an ABS plate with 100 gr / m ² spray. Furthermore, after setting at room temperature for 10 minutes, it was dried at 80 ° C. for 30 minutes to obtain a test piece. After this test piece was cured for 24 hours under conditions of 23 ° C. and 65% RH, a 2 mm wide, 100 square cross-cut tape peeling test was performed under the same conditions, and the coating mass remaining on the substrate without peeling. The eyes were counted and normal adhesion was evaluated.
Table 1 shows the coating composition.

(Hot water resistance)
The 60 ° gloss of the test piece prepared in the same manner as the normal adhesion was measured in advance using a digital variable gloss meter UGV-5D (manufactured by Suga Test Instruments), and then immersed in warm water of 40 ° C. for 240 hr. The occurrence of blisters immediately after immersion in warm water was evaluated. Moreover, the 60 degree gloss after drying the test piece after warm water immersion on 23 degreeC and 65% RH conditions for 24 hours was measured, and the change before and behind warm water immersion was evaluated as gloss retention. Furthermore, a 2 mm wide, 100 square cross-cut tape peel test was performed to evaluate secondary adhesion.

In the following, parts represent parts by mass, and% represents mass%.
(Example 1)
In a polymerization apparatus equipped with a stirrer, a thermometer, and a reflux condenser, 60 parts of plus coat Z-730 (solid content 25%, Tg 46 ° C., acid number 58) as a water dispersible polyester resin, plus coat Z-561 ( After adding 60 parts of solid content 25%, sulfonic acid group-containing type, Tg 64 ° C., acid value 2.5) and sufficiently performing nitrogen substitution, the temperature was raised. While maintaining the internal temperature at 75 ° C., 60 parts of deionized water, 30 parts of Pluscoat Z-561, 65 parts of styrene (St), 50 parts of methyl methacrylate (MMA), 35 parts of 2-ethylhexyl acrylate (2EHA), 2- 5% of 3 parts of hydroxyethyl methacrylate (2HEMA) and 3 parts of glycerin polyglycidyl ether (GLG) previously mixed and emulsified with a homomixer was added to the polymerization apparatus.

  Subsequently, 0.17 part of potassium persulfate and 2 parts of deionized water were added to initiate polymerization, and the reaction was carried out at 80 ° C. for 15 minutes. Further, the remaining 95% of the previous emulsion and 20 parts of a 1.5% aqueous potassium persulfate solution were added dropwise over 3 hours while maintaining the internal temperature at 80 ° C. Furthermore, it reacted at 80 degreeC for 2 hours, and cooled to room temperature (25 degreeC) after that. The theoretical Tg of the ethylenically unsaturated monomer used is 20 ° C. The properties of the obtained water-dispersed resin composition (emulsion) were as follows: nonvolatile content 50.0%, viscosity (BM viscometer, 60 rpm, 23 ° C.) 30 mPa · s, pH 6.5, MFT 50 ° C., average particle size It was 0.22 μm.

(Example 2)
In a polymerization apparatus equipped with a stirrer, a thermometer, and a reflux condenser, 60 parts of the same water-dispersible polyester resin plus coat Z-730 and 60 parts of plus coat Z-561 as in Example 1 were placed, and nitrogen substitution was sufficiently performed. After doing so, the temperature was raised. While maintaining the internal temperature at 75 ° C., 65 parts of deionized water, 30 parts of Pluscoat Z-561, 5 parts of sodium dodecylbenzenesulfonate (DBS), 65 parts of StMA, 50 parts of MMA, 35 parts of 2EHA, 3 parts of HEMA, 3 parts of GLG are homogenized. 5% of what was previously mixed and emulsified with a mixer was added to the polymerization apparatus.

  Subsequently, 0.17 part of potassium persulfate and 2 parts of deionized water were added to initiate polymerization, and the reaction was carried out at 80 ° C. for 15 minutes. Further, the remaining 95% of the previous emulsion and 20 parts of a 1.5% aqueous potassium persulfate solution were added dropwise over 3 hours while maintaining the internal temperature at 80 ° C. Furthermore, it reacted at 80 degreeC for 2 hours, and cooled to room temperature (25 degreeC) after that. The properties of the obtained water-dispersed resin composition were as follows: nonvolatile content 50.1%, viscosity (BM viscometer, 60 rpm, 23 ° C.) 62 mPa · s, pH 6.9, MFT 48 ° C., average particle size 0.21 μm Met.

(Example 3)
The composition of Example 1 was prepared by the same operation except that GLG was replaced with trimethylolpropane polyglycidyl ether (TPG). The properties of the obtained water-dispersed resin composition were as follows: nonvolatile content 49.8%, viscosity (BM type viscometer, 60 rpm, 23 ° C.) 45 mPa · s, pH 7.1, MFT 51 ° C., average particle size 0.25 μm Met.

(Comparative Example 1)
In a polymerization apparatus equipped with a stirrer, a thermometer, and a reflux condenser, 60 parts of the same water-dispersible polyester resin plus coat Z-730 and 60 parts of plus coat Z-561 as in Example 1 were placed, and nitrogen substitution was sufficiently performed. After doing so, the temperature was raised. While maintaining the internal temperature at 75 ° C., 57 parts of deionized water, 30 parts of water-dispersible polyester resin (solid content 25%, sulfonic acid group-containing type, Tg 64 ° C., acid value of 5 or less), St 65 parts, MMA 50 parts, 2EHA35 Part and 2% of 3 parts of HEMA previously mixed and emulsified with a homomixer were added to the polymerization apparatus.

  Subsequently, 0.17 part of potassium persulfate and 2 parts of deionized water were added to initiate polymerization, and the reaction was carried out at 80 ° C. for 15 minutes. Further, the remaining 95% of the previous emulsion and 20 parts of a 1.5% aqueous potassium persulfate solution were added dropwise over 3 hours while maintaining the internal temperature at 80 ° C. Furthermore, it reacted at 80 degreeC for 2 hours, and cooled to room temperature (25 degreeC) after that. The properties of the obtained water-dispersed resin composition were as follows: nonvolatile content 50.0%, viscosity (BM type viscometer, 60 rpm, 23 ° C.) 28 mPa · s, pH 6.2, MFT 48 ° C., average particle size 0.24 μm Met.

(Comparative Example 2)
In a polymerization apparatus equipped with a stirrer, a thermometer, and a reflux condenser, 60 parts of the same water-dispersible polyester resin plus coat Z-730 and 60 parts of plus coat Z-561 as in Example 1 were placed, and nitrogen substitution was sufficiently performed. After doing so, the temperature was raised. While maintaining the internal temperature at 75 ° C., 72 parts of deionized water, 30 parts of water-dispersible polyester resin (solid content 25%, sulfonic acid group-containing type, Tg 64 ° C., acid value of 5 or less), St65 parts, MMA 50 parts, 2EHA35 Part, 2HEMA 3 parts, and GLG 15 parts were mixed and emulsified in advance with a homomixer, and 5% was added to the polymerization apparatus.

  Subsequently, 0.17 part of potassium persulfate and 2 parts of deionized water were added to initiate polymerization, and the reaction was carried out at 80 ° C. for 15 minutes. Further, the remaining 95% of the previous emulsion and 20 parts of a 1.5% aqueous potassium persulfate solution were added dropwise over 3 hours while maintaining the internal temperature at 80 ° C. Furthermore, it reacted at 80 degreeC for 2 hours, and cooled to room temperature (25 degreeC) after that. The properties of the obtained water-dispersed resin composition were as follows: nonvolatile content 50.0%, viscosity (BM viscometer, 60 rpm, 23 ° C.) 25 mPa · s, pH 7.5, MFT 55 ° C., average particle size 0.21 μm Met.

Comparative Example 3
In a polymerization apparatus equipped with a stirrer, a thermometer, and a reflux condenser, 60 parts of deionized water was added, and after sufficient nitrogen substitution, the temperature was raised. While maintaining the internal temperature at 75 ° C., 5% of 80 parts of deionized water, DBS 5 parts, St 65 parts, MMA 50 parts, 2EHA 35 parts, 2HEMA 3 parts and GLG 3 parts previously mixed and emulsified with a homomixer is added to the polymerization apparatus. It was. Subsequently, 0.17 part of potassium persulfate and 2 parts of deionized water were added to initiate polymerization, and the reaction was carried out at 80 ° C. for 15 minutes. Further, the remaining 95% of the previous emulsion and 20 parts of a 1.5% aqueous potassium persulfate solution were added dropwise over 3 hours while maintaining the internal temperature at 80 ° C. Furthermore, it reacted at 80 degreeC for 2 hours, and cooled to room temperature (25 degreeC) after that. And it adjusted to pH7 using ammonia water, and the property of the obtained water dispersion resin composition is a non-volatile content 50.1%, a viscosity (BM type | mold viscosity meter, 60 rpm, 23 degreeC) 26 mPa * s, pH 6.9. The MFT was 28 ° C. and the average particle size was 0.28 μm.
The results are shown in Table 2.

表３の結果から明らかなように、実施例１、２及び３の場合はプラスチック基材に対する密着性が良好であり、しかも、ポリエステル、その架橋剤を適量使用することで、耐温水性に優れたコーティング剤として使用できる。 Table 3 shows a list of performance evaluation results of the aqueous dispersion compositions obtained in the steps of Examples 1 to 3 and Comparative Examples 1 to 3.

As is clear from the results in Table 3, in Examples 1, 2 and 3, the adhesion to the plastic substrate is good, and by using appropriate amounts of polyester and its cross-linking agent, it is excellent in hot water resistance. It can be used as a coating agent.

  The aqueous resin emulsion has good adhesion to various substrates, particularly plastic substrates, and has excellent durability, and can be used as a coating material, a primer, and the like.

Claims (5)

  An ethylenically unsaturated monomer in the presence of a water-soluble or water-dispersible polyester resin (a) having a carboxyl group and a crosslinking agent (c) having two or more functional groups capable of reacting with the carboxyl group of the polyester resin An aqueous resin emulsion obtained by radical polymerization of (b). Polyester resin (a) 2 to 75% by mass
Ethylenically unsaturated monomer (b) 97.8-20% by mass
Cross-linking agent (c) 0.2-5% by mass
The aqueous resin emulsion according to claim 1, wherein (a) ≧ (c) and (a) + (b) + (c) = 100% by mass are satisfied.   The aqueous resin emulsion according to claim 1 or 2, wherein the crosslinking agent (c) is a polyfunctional compound having at least two epoxy groups in the molecule.   The aqueous resin emulsion according to claim 1, comprising an emulsifier.   The coating agent for plastics containing the aqueous emulsion in any one of Claims 1-4.