JPH0660276B2 - Method for producing aqueous resin emulsion for sealer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an aqueous resin emulsion for sealers.

More specifically, it relates to a method for producing an aqueous resin emulsion for a sealer which, when applied to a porous substrate, provides a coating excellent in adhesion, water resistance, durability and smoothness by well impregnating the substrate. .

(Problems to be Solved by the Related Art and Invention) Conventionally, as a resin used for a sealer of an inorganic porous base material, a relatively low molecular weight moisture-curable urethane, a solvent type resin, etc. have been used. Is the toxicity, and the latter is a problem of fire risk and environmental pollution due to the use of organic solvents, and there is a strong demand for making it aqueous. Various water-based sealers containing water-soluble resin or water-dispersible resin as the main component have been investigated, but those containing water-soluble resin as the main component have water resistance, and water-dispersible resin as the main component. Those that do not have long-term durability because of poor impregnation and adhesion to the substrate. Further, a method of mixing and using a water-soluble resin and a water-dispersible resin has been studied, and for example, a method of blending 5 to 80% of a water-soluble resin with an acrylic emulsion (Japanese Patent Laid-Open No. SHO 63-242242).
61-141769), a method of blending polyvinyl alcohol with a specific polymer aqueous emulsion (JP-A-53-97081).
8) and the like have been proposed, but none of them has been found to satisfy the performances such as impregnation property and water resistance / durability with respect to the inorganic porous substrate. In addition, prior to the present invention, the present inventors disclosed in Japanese Patent Application No. 62-275850 an aqueous resin dispersion obtained by heat-treating an aqueous resin dispersion and a specific polyvinyl alcohol under specific conditions as an inorganic porous substrate. However, it was found that the impregnation property and the water resistance / durability were satisfied, but in view of the recent tendency of inorganic porous substrates to become non-asbestos, sufficient impregnation property / adhesion property is not yet satisfied. Was recently discovered. On the other hand, although the method using an epoxy emulsion has excellent impregnating properties for the substrate, it uses a curing agent, so it becomes a two-part solution, and handling is complicated, and there are problems of pot life and restrictions on the time for topcoating. Has many problems on. In addition, since a large amount of emulsifier is required when emulsifying an epoxy resin in water, a decrease in water resistance cannot be avoided. From the above, it is the current situation that an aqueous sealer that is easy to handle and has sufficient performance has not been obtained.

(Technical Means for Solving Problems) The present invention has the above-mentioned problems, that is, toxicity of a sealer mainly composed of moisture-curable urethane or solvent-based resin, risk of fire, environmental pollution, etc. This is a solution to all problems, such as lack of water resistance, lack of impregnation, lack of adhesion, and lack of durability, which water-based sealers have.

As a result of earnest studies by the present inventors, an aqueous resin obtained by heating a mixture of a hydrophobic epoxy resin emulsified with a specific polyvinyl alcohol in a water-based resin dispersion and a polymerization initiator at a temperature of 40 ° C. or higher. It was found that the emulsion has no drawbacks of conventional water-soluble resins and water-dispersible resins, and there is no concern about toxicity or environmental pollution.
The present invention has been completed.

That is, the present invention provides a mixture of a hydrophobic epoxy resin emulsified with polyvinyl alcohol having a saponification degree of 80 mol% or more and a polymerization initiator in an aqueous resin dispersion obtained by emulsion polymerization of a vinyl-based polymerizable monomer. The present invention relates to a method for producing an aqueous resin emulsion for a sealer, which is obtained by heating at a temperature of 40 ° C or higher.

The aqueous resin dispersion in the present invention is not particularly limited as long as it is conventionally known, but an aqueous resin dispersion of a vinyl polymer is preferable, for example, an acrylic resin emulsion,
Examples thereof include styrene-acrylic resin emulsion, ethylene-vinyl acetate emulsion, acrylic-styrene-vinyl acetate emulsion, styrene-vinyl acetate emulsion, vinylidene chloride emulsion, vinyl chloride emulsion and the like. Among these, acrylic resin emulsion and styrene-acrylic resin emulsion are particularly preferable. Such an aqueous resin dispersion is obtained by emulsion-polymerizing a vinyl-based polymerizable monomer by a known method, and the vinyl-based polymerizable monomer that can be used is not particularly limited, and examples thereof include methyl (meth). ) Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
(Meth) acrylates such as 2-ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; aromatic unsaturated monomers such as styrene, α-methylstyrene, α-chlorostyrene, vinyltoluene; vinyl fluoride, chloride Vinyl halides such as vinyl and vinylidene chloride; Unsaturated cyan compounds such as (meth) acrylonitrile; Vinyl esters such as vinyl acetate and vinyl propionate; Hydroxyl such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate Group-containing unsaturated monomers; (meth) acrylamide, N-
Unsaturated acid amides such as methylol (meth) acrylamide or its derivatives; dimethylaminoethyl (meth)
Amino group-containing unsaturated monomers such as acrylates; Polyfunctional unsaturated monomers such as divinylbenzene, ethylene glycol di (meth) acrylate; Glycidyl (meth)
Glycidyl group-containing unsaturated monomers such as acrylate and allyl glycidyl ether; unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, monomethyl fumarate and monoethyl maleate or The derivative etc. can be mentioned and these 1 type (s) or 2 or more types can be used.

The aqueous resin dispersion in the present invention may be obtained by emulsion polymerization of the vinyl-based polymerizable monomer using a polymerization initiator in the presence or absence of an emulsifier, and examples of the polymerization initiator include ammonium persulfate and persulfate. Known water-soluble or oil-soluble initiators such as potassium, hydrogen peroxide and benzoyl peroxide can be used. At this time, a redox initiator may be used by using sodium bisulfite, L-ascorbic acid or the like as a reducing agent. Examples of the emulsifier used as needed include anionic activators such as sodium lauryl sulfate and nonionic activators such as polyoxyethylene alkyl ether. Further, a chain transfer agent such as lauryl mercaptan may be used for the purpose of controlling the molecular weight during the polymerization. In addition, multistage emulsion polymerization may be carried out by changing the composition of the polymerizable monomer or the like at each stage during emulsion polymerization.

The polyvinyl alcohol used in the present invention has a saponification degree of 80 mol% or higher, preferably 87 mol% or higher. When polyvinyl alcohol having a saponification degree of less than 80 mol% is used, the crystallinity is lowered or the hydrophilicity is increased, and the water resistance of the aqueous resin emulsion obtained by the production method of the present invention is increased when it is used as a sealer. It is not preferable because it decreases.
The amount of the polyvinyl alcohol used in the present invention is not particularly limited, but it is aqueous in terms of adhesion and water resistance to the base material when the aqueous resin emulsion for sealer in the present invention is used for coating a porous base material. The solid content ratio is preferably 1 to 40 parts by weight, and more preferably 5 to 35 parts by weight, based on 100 parts by weight of the resin emulsion. The degree of polymerization of polyvinyl alcohol in the present invention is preferably in the range of 200 to 2600, more preferably 500 to 2400 in terms of water resistance and viscosity of the finally obtained aqueous resin emulsion. .
As the polyvinyl alcohol used in the present invention, a polymer in which a part of the vinyl alcohol unit is replaced by another vinyl monomer unit or a part of the hydrogen of the hydroxyl group present in the polyvinyl alcohol is replaced by another compound. It may be a polymer, for example, a polymer partially butyralized.

The epoxy resin in the present invention is not particularly limited as long as it is hydrophobic, but any conventionally known epoxy resin may be used. For example, bisphenol A type epoxy resin, cycloaliphatic epoxy resin, novolac type epoxy resin, resorcin type epoxy resin, bisphenol F type epoxy resin, halogenated bisphenol type epoxy resin, tetrahydroxyphenylethane type epoxy resin, glycerin triether type epoxy resin. Polyolefin type epoxy resin, epoxidized soybean oil, etc. are mentioned, and among these, bisphenol A type epoxy resin and novolac type epoxy resin are particularly preferable. These epoxy resins may be epoxy resins in which a part of epoxy groups are replaced with other substituents, and may be monofunctional or polyfunctional. The hydrophobic epoxy resin used in the present invention has an epoxy equivalent of 150 to 3500, preferably an epoxy equivalent of 180 to 3000. The amount of the epoxy resin used in the present invention is not particularly limited, but when the water-based resin emulsion for sealer obtained by the production method of the present invention is used for coating a porous substrate, adhesion to the substrate, water resistance From the viewpoints of stability and stability during storage, the solid content ratio is preferably 1 to 40 parts by weight, more preferably 5 to 35 parts by weight, based on 100 parts by weight of the aqueous resin dispersion.

In the production method of the present invention, the epoxy resin is emulsified with polyvinyl alcohol, and the emulsifying device used at this time is not particularly limited, but an emulsifier generally used for improving the emulsion stability of the epoxy resin may be used in combination. . However, the amount of the emulsifier used is preferably 5 parts by weight or less in terms of solid content with respect to 100 parts by weight of the epoxy resin, and the water resistance of the aqueous resin emulsion obtained by adding more than this will decrease. or,
The solid epoxy resin is previously dissolved in a solvent to facilitate emulsification. Examples of the solvent used at this time include ketones, esters, ethers and alcohols, but there is no particular limitation.

As the polymerization initiator used when obtaining the aqueous resin emulsion for a sealer by the production method of the present invention, the one used for emulsion polymerization of the aqueous resin dispersion is used as it is, and persulfate is particularly preferable. Moreover, you may use a reducing agent as needed. The amount of the polymerization initiator used is preferably in the range of 0.01 to 5 parts by weight, more preferably 0.03 to 3 parts by weight, based on 100 parts by weight of the polyvinyl alcohol used.

The aqueous resin emulsion for sealers obtained by the production method of the present invention is a mixture of the above aqueous resin dispersion, a hydrophobic epoxy resin emulsified with polyvinyl alcohol having a saponification degree of 80 mol% or more, and a polymerization initiator at 40 ° C. It is obtained by heat treatment at the above temperature, preferably at a temperature of 50 to 95 ° C. In the present invention, the significance of heat-treating the above mixture is that, when compared to a mere mixture of an aqueous resin dispersion and a hydrophobic epoxy resin emulsified with polyvinyl alcohol, it is applied to a porous substrate, particularly an inorganic porous substrate. That is, the adhesiveness and water resistance are improved without impairing the impregnation into the substrate, and the amount of polyvinyl alcohol used can be reduced. When the temperature of the heat treatment is lower than 40 ° C., the decomposition of the polymerization initiator becomes extremely slow, the solubility of polyvinyl alcohol in water decreases, and the effect of the heat treatment decreases, so that the aqueous resin emulsion for sealer having the above characteristics is obtained. Can't get

The aqueous resin emulsion for a sealer obtained in the present invention is used as it is as a sealer for an inorganic porous substrate, and if necessary, a film forming aid, a hydrophilic resin, a pigment, a filler, a toner,
You may mix and use additives, such as a dispersing agent and a wetting agent. However, the amount of the pigment, the filler and the toner used is 300 per 100 parts by weight of the aqueous resin emulsion for sealer (calculated as non-volatile content) so as not to impair the characteristics of the aqueous resin emulsion for sealer obtained by the production method of the present invention. It is preferable that the amount is less than or equal to parts by weight.

(Effect of the invention) The aqueous resin emulsion for a sealer obtained by the production method of the present invention is a mixture of an aqueous resin dispersion, a hydrophobic epoxy resin emulsified with polyvinyl alcohol, and a polymerization initiator heated at a temperature of 40 ° C or higher. Since it is obtained by treatment, a mixture of an aqueous resin dispersion and polyvinyl alcohol, a mixture of a polymerization initiator added to this mixture and a heat treatment, or an emulsion of a hydrophobic epoxy resin with polyvinyl alcohol is simply added to the aqueous resin dispersion. Compared to the mixture with added substances, it is superior in adhesion to the substrate and water resistance such as warm water resistance, durability such as frost damage resistance, lifting resistance at the time of coating the top coating, and top coating film. Adhesion between layers is improved. Further, as compared with the epoxy emulsion, since it can be handled with one liquid, the complexity of handling and the problem of pot life are eliminated, and there is also no limitation on the coating interval at the time of topcoating. Therefore, the aqueous resin emulsion according to the present invention can be suitably used as a sealer for substrates such as mortar, concrete and calcium silicate plate.

(Examples) The present invention is described in detail below with reference to examples, but the present invention is not limited to the following examples. The parts in the examples are by weight unless otherwise specified.

Example 1 1 equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer
After deionized water (500 parts) and sodium lauryl sulfate (8 parts) were charged in the separable flask (1), the temperature was raised to 70 ° C. with stirring while blowing nitrogen gas. Then, a polymerizable monomer mixture consisting of 160 parts of methyl methacrylate, 80 parts of styrene, 152 parts of butyl acrylate and 8 parts of methacrylic acid was uniformly added dropwise over 2 hours. During this period, 10 parts of a 10% ammonium persulfate aqueous solution was uniformly added dropwise over 2 hours. After aging for 1 hour, it was cooled and 6.3 parts of 25% aqueous ammonia was added. The aqueous resin dispersion (1) thus obtained had a nonvolatile content of 4
The characteristic values were 3.5%, pH 9.0, viscosity 150 cps (B type viscometer, No. 2 rotor, 30 rpm, 25 ° C.), and minimum film forming temperature 35 ° C. Kuraray Poval PVA-
117 (polyvinyl alcohol manufactured by Kuraray Co., Ltd .: polymerization degree 1700, saponification degree 98 to 99 mol%) 10% aqueous solution 6
After charging 0 part to a separable flask, 6 parts of ADEKA RESIN EP-4100 (bisphenol epoxy resin manufactured by Asahi Denka Co., Ltd .: epoxy equivalent 180 to 200, molecular weight about 360) was added with stirring and stirring at 200 rpm. After emulsifying at a speed of 10 minutes, 200 parts of the aqueous resin dispersion (1) was added, and then the temperature was raised to 70 ° C. with stirring while blowing nitrogen gas. Then, 1 part of a 1% aqueous solution of ammonium persulfate was added, and heat treatment was performed at 70 ° C. for 60 minutes. After completion of heating, the mixture was cooled to obtain an aqueous resin emulsion for sealer (1). The obtained water-based resin emulsion for sealer (1) had a nonvolatile content of 37.1%, a pH of 8.3, and a viscosity of 9
00cps (B type viscometer, No.3 rotor, 30rp
m, 25 ° C.) and the minimum film forming temperature of 10 ° C.

20 g / m ² of solid content of the obtained aqueous resin emulsion for sealer (1) was coated on the inorganic porous substrate shown in Table ² , and
After drying in a hot air drier at 0 ° C. for 10 minutes, the adhesion of the coating film to the substrate, hot water resistance and frost damage resistance were examined. On top of the coating film of the water-based resin emulsion for sealer (1), the top coating composition obtained by the coating composition shown in Table 1 was added in a solid content of 40.
After coating with g / m ² and drying with a hot air dryer at 120 ° C. for 10 minutes, the suitability for top coating was examined. The results were as shown in Table 2. Similar tests were performed on the aqueous resin emulsions for sealers obtained in the following Examples and Comparative Examples.

In addition, the obtained aqueous resin emulsion for sealer (1) was heated to 50 ° C.
It was stored for 30 days at room temperature, and its storage stability was examined. Similar tests were carried out on the aqueous resin emulsions for sealers obtained in the following Examples and Comparative Examples, and the results are shown in Table 3.

Example 2 After the same separable flask as used in Example 1 was charged with 350 parts of deionized water, the temperature was raised to 60 ° C. with stirring while blowing nitrogen gas. After that, 200 parts of methyl methacrylate and 1 of cyclohexyl methacrylate
Emulgen 950 (manufactured by Kao Corporation) in a polymerizable monomer mixture consisting of 00 parts, 90 parts of 2-ethylhexyl acrylate, 4 parts of glycidyl methacrylate and 6 parts of acrylic acid.
10 parts of polyoxyethylene nonylphenyl ether,
Rebenol WZ (manufactured by Kao Corporation: 25% aqueous solution of sodium polyoxyethylene nonylphenyl ether sulfate)
A pre-emulsion mixture obtained by adding 16 parts and 120 parts of deionized water was uniformly added dropwise over 3 hours. During this period, 60 parts of a 2% aqueous solution of potassium persulfate and 12 parts of a 5% aqueous solution of sodium bisulfite were added to the flask every 10 minutes until the addition of the pre-emulsion mixture was completed.
After completion of dropping, the mixture was aged for 1 hour and cooled. The aqueous resin dispersion (2) thus obtained had a nonvolatile content of 42.6.
%, PH 2.7, viscosity 400 cps.
After charging 50 parts of Epicoat 1007 (bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd .: epoxy equivalent 1750 to 2150, molecular weight about 2900) into a flask, after adding 50 parts of butyl cellosolve, 120
The mixture was heated to ℃, dissolved under stirring, cooled, and added with 6 parts of Adecanol NK-511 (Emulsifier for epoxy resin: 30% aqueous solution manufactured by Asahi Denka Co., Ltd.) and mixed well with stirring. It was After that, the stirring speed in the flask is 400 rpm.
After adjusting to 290 parts, 290 parts of a 10% aqueous solution of Kuraray Poval PVA-205 (manufactured by Kuraray Co., Ltd .: polymerization degree 500, saponification degree 87 to 89 mol%) was added to a separable flask and emulsified over 30 minutes. , The whole amount was transferred to a separable flask. Thereafter, 200 parts of the aqueous resin dispersion (2) was added to the separable flask and the temperature was raised to 50 ° C. with stirring while blowing nitrogen gas, and 14.5 parts of 2% aqueous solution of hydrogen peroxide and 5% L were added. -3 parts of an ascorbic acid aqueous solution was added and heat treatment was performed for 2 hours. After cooling, 1.2 parts of 25% aqueous ammonia solution was added to obtain an aqueous resin emulsion for sealer (2). The obtained water-based resin emulsion for sealer (2) had a non-volatile content of 25.9%, a pH of 8.0 and a viscosity of 18
00cps (B type viscometer, No.3 rotor, 30rp
m, 25 ° C.) and the minimum film formation temperature of 0 ° C. or less.

Example 3 In a separable flask, 40 parts of butyl cellosolve and 40 parts of Epicoat 154 (Novolac type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd .: epoxy equivalent 176 to 181) were added.
Part, ADEKA RESIN EPU-4-75X (Usahi Denka Co., Ltd. urethane-modified epoxy resin: epoxy equivalent 750-85)
80 parts of 0, xylene solution, 75%) was charged, and the temperature was raised to 100 ° C. with stirring to dissolve the epoxy resin over 30 minutes. Next, in the glass container of 1, Kuraray Poval PV
A-224E (polyvinyl alcohol manufactured by Kuraray Co., Ltd .:
After charging 300 parts of a 10% aqueous solution having a polymerization degree of 2400 and a saponification degree of 87 to 89 mol%), a homomixer was installed, and 6
After the stirring was started at 000 rpm, 60 parts of the epoxy resin solution dissolved above was added, and the epoxy resin was emulsified over 10 minutes. Then, the whole amount was transferred to a separable flask of 1, and the temperature was raised to 80 ° C. with stirring while blowing nitrogen gas. Then, 322 parts of the aqueous resin dispersion (1) used in Example 1 was added, and 15 parts of a 2% aqueous solution of potassium persulfate was added while keeping the internal temperature at 80 ° C. The resulting water-based resin emulsion for sealer (3) had a nonvolatile content of 2
The characteristic values were 8.7%, pH 8.5, viscosity 2300 cps (B type viscometer, No. 3 rotor, 30 rpm, 25 ° C.), and minimum film forming temperature of 0 ° C. or less.

Comparative Example 1 200 parts of the aqueous resin dispersion (1) obtained in Example 1 was mixed with 150 parts of a 10% aqueous solution of Kuraray Poval PVA-117 to obtain a comparative aqueous resin emulsion for sealer (1). It was This comparative water-based resin emulsion for sealer (1) had a non-volatile content of 29.0%, a pH of 8.9 and a viscosity of 2200 cps.
(B-type viscometer), the minimum film forming temperature was 0 ° C. or less.

Comparative Example 2 200 parts of the aqueous resin dispersion (1) obtained in Example 1 and Kuraray Poval PVA-17 were placed in a separable flask of 1.
150 parts of a 10% aqueous solution of 7 was charged, and the temperature was raised to 70 ° C. with stirring while blowing nitrogen gas. Then, 1 part of a 1% aqueous solution of ammonium persulfate was added to the mixture for 70 minutes for 70 minutes.
Heat treatment was performed at ℃. After the heat treatment, the mixture was cooled to obtain an aqueous resin emulsion for sealer (2) for comparison. The obtained aqueous resin emulsion for a sealer for comparison has a nonvolatile content of 28.9% and a pH.
8.7, a viscosity of 2100 cps (B type viscometer), and a minimum film formation temperature of 0 ° C. or less were shown.

Comparative Example 3 A separable flask of 1 was charged with Kuraray Poval PVA-1.
After 60 parts of 10% aqueous solution of 17 was charged, 6 parts of ADEKA RENGE EP-4100 was added with stirring to 200 rpm.
After emulsifying at a stirring speed of 10 minutes, Example 1
200 parts of the aqueous resin dispersion (1) obtained in (1) was added to obtain a comparative aqueous resin emulsion for sealer (3). The obtained comparative aqueous resin emulsion for sealer (3) had a nonvolatile content of 37.2%, a pH of 8.5, a viscosity of 1000 cps (B type viscometer), and a minimum film forming temperature of 10 ° C.

Comparative Example 4 600 parts of a 10% aqueous solution of Kuraray Poval PVA-117 was charged into a separable flask (1) equipped with a stirrer, a reflux condenser and a thermometer, and then Adeka Resin EP-4100.
Was charged in 60 parts, and the epoxy resin was emulsified at a stirring speed of 200 rpm for 10 minutes. Then, while blowing nitrogen gas, the temperature was raised to 70 ° C. with stirring, 8 parts of a 1% aqueous solution of ammonium persulfate was added, and heat treatment was performed at 70 ° C. for 60 minutes. To 66.8 parts of the obtained heat-treated epoxy resin emulsion, 200 parts of the aqueous resin dispersion (1) shown in Example 1 was added and mixed well for 10 minutes.
An aqueous resin emulsion for sealer (4) for comparison was obtained.

Comparative Example 5 After charging 80 parts of a 10% aqueous solution of Kuraray Poval PVA-117 in a separable flask, the stirring speed was 200 r.
Adjusted to pm, 60 parts of ADEKA RESIN EP-4100 and 20 parts of emulsifier ADEKANOL NK-511 were added,
The emulsification was performed for 10 minutes. Then, 150 parts of the aqueous resin dispersion (1) used in Example 1 was added, and the mixture was stirred under stirring to give 7
The temperature was raised to 0 ° C., 8 parts of a 1% aqueous solution of ammonium persulfate was added, the mixture was heated at 70 ° C. for 60 minutes, and after cooling, an aqueous resin emulsion for sealer (5) for comparison was obtained.
The obtained comparative water-based resin emulsion for sealer (5) had a nonvolatile content of 43.7%, pH 8.0, a viscosity of 1200 cps,
The characteristic value of the minimum film forming temperature of 12 ° C. is shown.

Comparative Example 6 After 50 parts of Epicoat 1007 were charged in a flask,
Add 50 parts of butyl cellosolve, raise the temperature to 120 ° C,
After dissolving under stirring, the mixture is cooled, and Adecanol NK-5 is added.
6 parts of 11 were added and dissolved. After that, a homomixer was installed, the stirring speed was adjusted to 6000 rpm, and 200 parts of the aqueous resin dispersion (2) obtained in Example 2 was added and it was tried to emulsify for 30 minutes, but it was stable. No emulsion was obtained.

Comparative Example 7 After charging 100 parts of deionized water in a flask, the stirring speed was adjusted to 400 rpm, and ADEKA RESIN EP-410 was used.
0 and 40 parts of Adecanol NK-511 were added, and emulsification was performed for 30 minutes. Then, after adding 200 parts of the aqueous resin dispersion (1) obtained in Example 1, the temperature was raised to 70 ° C. with stirring while blowing nitrogen gas, and 8 parts of a 1% aqueous solution of ammonium persulfate was added. hand,
A heat treatment was performed at 70 ° C. for 60 minutes to obtain a comparative aqueous resin emulsion for sealer (7). The obtained water-based resin emulsion for a sealer (7) for comparison had a nonvolatile content of 36.3.
%, PH 8.1, viscosity 720 cps (B type viscometer), minimum film forming temperature 27 ° C.

Comparative Example 8 Denacol EX-832 (Nagase Kasei Co., Ltd.) was placed in a flask.
Water-soluble epoxy resin: 25 parts of epoxy equivalent 280) was charged, 12.1 parts of 25% ammonia water was added, and further 10% aqueous solution of Kuraray Poval PVA-205 350.
Parts were charged and dissolved with stirring. Then, Example 2
200 parts of the aqueous resin dispersion (2) used in Step 2 was added, the temperature was raised to 70 ° C. while blowing nitrogen gas, 17.5 parts of a 1% aqueous solution of ammonium persulfate was added, and the mixture was heated to 60 ° C. at 70 ° C.
A heat treatment was carried out for 1 minute to obtain a water-based resin emulsion for sealer (8) for comparison. The obtained comparative water-based resin emulsion for sealer (8) had a nonvolatile content of 24.0% and a pH of 10.
3, 680 cps (B type viscometer), and a minimum film forming temperature of 0 ° C. or less was specified.

Test Method Primary Adhesion: The coating film was cut into 5 × 5 crosses with a cutter knife at 3 mm intervals, a polyester adhesive tape was pressure-bonded thereto, and then peeled off to examine the remaining state of the coating film.

◯: The coating film does not peel off at all.

Δ: The coating film was partly peeled off.

X: The coating film was completely peeled off.

Warm water resistance: The test piece coated with the coating film was immersed in warm water at 60 ° C. for 5 days, dried at room temperature for 2 days, and the adhesion was examined by the same method as above.

Frost resistance: immersion in water at 10 ° C. for 2 hours → freezing in air at −20 ° C. for 2 hours as one cycle, 200 and 300 cycles, then drying for 2 days at room temperature, and adhesion by the same method as above. Examined.

Topcoat suitability: A coating material obtained by the formulation shown in Table 1 was applied to a base material coated with an aqueous resin emulsion for a sealer, and the solid content was 40 g /
After applying m ² and drying in a hot air dryer at 120 ° C. for 10 minutes, the adhesion was examined by the same method as in the primary adhesion test.

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Claims (5)

[Claims] 1. A mixture of a hydrophobic epoxy resin emulsified with polyvinyl alcohol having a saponification degree of 80 mol% or more and a polymerization initiator is added to an aqueous resin dispersion obtained by emulsion polymerization of a vinyl-based polymerizable monomer. A method for producing an aqueous resin emulsion for a sealer, which is obtained by heating at a temperature of ℃ or higher. 2. An aqueous resin dispersion 1 containing polyvinyl alcohol.
The method for producing an aqueous resin emulsion for a sealer according to claim 1, which is used in a range of 1 to 40 parts by weight in terms of solid content relative to 00 parts by weight. 3. The degree of polymerization of polyvinyl alcohol is 200 to
The method for producing an aqueous resin emulsion for a sealer according to claim 1, which is in the range of 2600. 4. An aqueous resin dispersion 10 containing a hydrophobic epoxy resin.
The method for producing an aqueous resin emulsion for a sealer according to claim 1, which is used in a range of 1 to 40 parts by weight in terms of solid content relative to 0 parts by weight. 5. The epoxy equivalent of the hydrophobic epoxy resin is 15
The method for producing an aqueous resin emulsion for a sealer according to claim 1, which is in the range of 0 to 3,500.