JP2737364B2 - Method for producing aqueous resin dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Industrial Application Field] The present invention relates to an aqueous emulsion polymerization method of a radical polymerizable macromonomer and another radical polymerizable monomer, which is obtained by the present invention. The aqueous resin dispersibility is based on a graft polymer obtained by a macromonomer method, and the average particle size is 1 μm.
It is an emulsion composed of the following fine resin particles, and is suitable as a paint and an adhesive.

[Conventional technology]

In recent years, graft polymers have been recognized for their usefulness as high-performance polymer materials, and have been widely used industrially.

Conventionally, a graft polymer uses a polymerization initiator such as a radical polymerization initiator, and in the presence of a polymer compound serving as a trunk polymer, a solution of a monomer different from the monomer forming the polymer compound is used. Although it has been produced by a method of polymerization, bulk polymerization or emulsion polymerization, the graft polymer produced by such a method has a problem that its purity is low in that it contains a large amount of ungrafted polymer.

On the other hand, a method of copolymerizing a high molecular weight monomer having a polymerizable group at the terminal of the molecule, that is, a macromonomer, with another copolymerizable monomer (hereinafter, referred to as a macromonomer method)
Can produce a graft polymer with a high graft efficiency, and has recently been receiving attention.

The production of the graft polymer by the macromonomer method
In the past, generally, a macromonomer was dissolved and polymerized in an organic solvent together with a monomer to be copolymerized with the macromonomer, or by a suspension polymerization in an aqueous medium. Graft polymers obtained by suspension polymerization are difficult to handle in liquid form as an aqueous dispersion because the graft polymer obtained by suspension polymerization separates into a liquid phase and a solid phase. There has been a strong demand for an aqueous emulsion-type graft polymer comprising an emulsified dispersion having a small particle diameter.

Although there are few methods for producing a graft polymer by a macromonomer method by aqueous emulsion polymerization, there are the following proposals.

For example, Joseph P. Kennedy
dy) et al., Polymer Builetin13
No. pp. 441-446 (1985), the following method is described for emulsion copolymerization of styrene with a polyisobutylene-based macromonomer having a p-vinylphenyl group at one end.

That is, the above polyisobutylene-based macromonomer is dissolved in a styrene monomer, this solution is emulsified in water with sodium salt of nonylphenoxypolyethoxyethanol sulfate, and atomized to an average particle size of about 0.24 μm, followed by polymerization. It is reported that a graft polymer was obtained in high yield by adding an oil-soluble azobisisobutyronitrile (hereinafter referred to as AIBN) as an initiator and polymerizing.

However, the average molecular weight of the graft polymer obtained by the method proposed by Kenney et al. Is as low as about 6,000 to 50,000 in number average molecular weight, which poses a problem that practical applications are limited. According to this, when a macromonomer other than the polyisobutylene-based macromonomer, for example, a polyacrylate-based macromonomer or a styrene / acrylonitrile copolymer-based macromonomer, is used, a large amount of grids are generated in the polymerization method. And a good emulsified dispersion could not be obtained.

In JP-A-62-64814, a macromonomer is dissolved in an organic solvent such as toluene, and an emulsifier is added thereto to prepare an emulsion having a fine particle size in water. A method for producing an aqueous emulsion-type graft polymer by adding a monomer to be copolymerized with a macromonomer and performing radical copolymerization has been proposed. However, in the above method, since the macromonomer is formed into micelles separately from the other monomers to be copolymerized, the polymerization of macromonomers and other monomers becomes dominant, and the formation of a graft polymer is caused. There was a problem that the rate was inferior.

(B) Configuration of the Invention [Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the following surfactant was used as an emulsifier, and an oil-soluble radical polymerization initiator was used as a macromonomer. Together with a new oil-based copolymerizable vinyl monomer, and by simultaneously emulsifying and dispersing them in an aqueous medium, the macromonomer and the copolymerizable vinyl monomer can be used even if the amount of the emulsifier used is small. Was found to be easily emulsified and dispersed in fine micelles having an average particle diameter of 1 μm or less and having a very high grafting efficiency in a graft polymer obtained by polymerizing the subsequently emulsified and dispersed monomers. Thus, the present invention has been completed.

That is, the present invention dissolves a macromonomer having a radical polymerizable group and an oil-soluble radical polymerization initiator in another vinyl monomer copolymerizable with the macromonomer, and the obtained solution is dissolved in an aqueous medium as follows. An aqueous resin dispersion comprising emulsifying and dispersing in the presence of an emulsifier comprising a surfactant (A) or (B), and then raising the temperature to copolymerize the macromonomer with another vinyl monomer. It is a method of manufacturing the body.

Surfactant (A); an alkali metal sulfosuccinate-based anionic surfactant.

Surfactant (B) comprising an anionic surfactant of a sulfonic acid alkali metal salt or a sulfate ester alkali metal salt other than the above (A) and a nonionic surfactant having an HLB value of 10 or more. A surfactant containing the former in a proportion of 2 to 98% by weight and the latter in a proportion of 98 to 2% by weight based on the total amount of

 Hereinafter, the present invention will be described in more detail.

(Macromonomer)

The macromonomer in the present invention comprises a polymer portion and a radical polymerizable group bonded thereto, and has a radical polymerizable group at one end of the molecular weight, and has a number average molecular weight of 1000.
It is a high molecular weight monomer having a number average molecular weight of 2,000 to 50,000.

When the number average molecular weight of the macromonomer is less than 1,000,
The branch polymer in the obtained graft polymer is too short, and the physical properties unique to the graft polymer are not expressed.
If it exceeds 10,000, the copolymer with the vinyl monomer to be copolymerized will be poor, and the yield of the graft polymer will be low.

Examples of the radical polymerizable group include an acryloyl group, a methacryloyl group, a styryl group, an allyl group, a vinylbenzyl group, a vinyl ether group, a vinylalkylsilyl group, a vinylketone group, and an isopenyl group.

The monomers constituting the polymer portion of the macromonomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, -(Meth) acrylates such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, hydroxy Hydroxyalkyl (meth) acrylates such as propyl (meth) acrylate and hydroxybutyl (meth) acrylate, (meth) acrylamide, N
-(Meth) acrylamides such as methylol acrylamide and diacetone acrylamide, fluorine-containing acrylates such as polyfluoroacrylate and perfluoroalkyl acrylate, silicone-containing acrylates such as acryloyloxypropyltrimethoxysilane, styrene, α-methylstyrene, p- Styrene compounds such as methylstyrene, (meth) acrylonitrile, vinylidene cyanide, nitrile group-containing monomers such as α-cyanoethyl acrylate, vinyl acetate such as vinyl acetate, vinyl propionate, vinyl chloride, vinyl fluoride, vinylidene chloride, Vinyl halides such as vinylidene fluoride, olefinic compounds such as butadiene, isoprene and isobutylene, and polyethylene glycol mono (meth) acrylate And polyalkylene glycol (mono) methacrylates such as polypropylene glycol mono (meth) acrylate, vinylpyrrolidone, vinylpyridine and maleic anhydride, and these can be used alone or in combination of two or more.

In order to obtain a resin dispersion used for a coating agent such as a paint,
It is necessary to use a macromonomer having a Tg of 50 ° C. or higher. Examples of the macromonomer include macromonomers having a polymethyl methacrylate or polystyrene skeleton. When a macromonomer having a Tg of less than 50 ° C. is used, the gloss and blocking resistance of the coating film are poor.

The production of the macromonomer can be performed by various known methods.A typical production method is to form a monofunctional living polymer by, for example, solution polymerization using an anionic polymerization initiator, and to obtain a desired molecular weight. Upon arrival, a method of reacting with a terminator having a radical polymerizable group such as a vinyl group (JP-A-51-125186), or a method in which a radical is added in the presence of a mercaptan-based radical chain transfer agent having a carboxyl group or the like. A method in which a polymer having a carboxyl group at the molecular terminal obtained by polymerizing a polymerizable monomer is reacted with glycidyl (meth) acrylate (Japanese Patent Publication No. 43-11224), and group transfer. A polymerization method (Japanese Patent Application Laid-Open No. 62-62801), an iniferter polymerization method, and the like can also be used.

In the present invention, it is preferable to use a macromonomer in which a (meth) acryloyl group having a high radical polymerizability is introduced into a terminal group of a polymer skeleton produced by a radical polymerization method or an anion polymerization method.

In the present invention, the macromonomer needs to be emulsified and dispersed in an aqueous medium in a state of being dissolved in a vinyl monomer to be copolymerized with the macromonomer, together with an oil-soluble radical polymerization initiator described later.

By adopting the above means, micelles containing the macromonomer, the comonomer and the polymerization initiator together can be formed in the individual emulsified fine particles, that is, micelles, so that the polymerization initiator concentration in the micelles can be easily controlled. In addition, since the macromonomer and the copolymerized vinyl monomer coexist in one micelle from the beginning, their copolymerization is likely to occur. Therefore, according to the present invention, according to the present invention, the emulsification An excellent effect that the production efficiency of the graft polymer is higher than that of the legal method is exhibited.

When the macromonomer and the oil-soluble radical polymerization initiator are dissolved in the vinyl monomer, an appropriate amount of an organic solvent such as toluene, xylene, methyl isobutyl ketone and ethyl acetate may be used in combination to increase the solubility.

(Comonomer)

In the present invention, the monomer to be copolymerized with the macromonomer is a hydrophobic vinyl monomer or a vinyl monomer mixture which can be emulsified in an aqueous medium, and is a vinyl monomer or a vinyl monomer which is liquid at ordinary temperature. Preference is given to a mixture of vinyl monomers mainly composed of a body.

Hydrophobic and liquid vinyl monomers that can be copolymerized with macromonomers at room temperature include methyl methacrylate,
(Meth) acrylates such as ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and poly (meth) acrylate Fluorine-containing acrylates such as fluoroacrylates and perfluoroalkyl acrylates, silicone-containing acrylates such as acryloyloxypropyltrimethoxysilane, styrene-based compounds such as styrene, α-methylstyrene and p-methylstyrene, (meth) acrylonitrile, vinyl acetate, And vinyl esters such as vinyl propionate.

Can be used with the vinyl monomer of a hydrophobic liquid,
Other vinyl monomers include methyl acrylate,
Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic acid, vinyl Hydrophilic vinyl monomers such as pyrrolidone and vinylpyridine, polyfunctional vinyl monomers such as divinylbenzene, diallyl phthalate and diethylene glycol diacrylate, and stearyl (meth) acrylate, behenyl (meth) acrylate, maleic anhydride, butadiene, And isoprene and vinylidene chloride.

The preferred copolymerization ratio between the macromonomer and the comonomer is 1 to 50% by weight of the macromonomer and the comonomer.
50-99% by weight. 50% by weight of macromonomer
If it exceeds, gelation is likely to occur during polymerization. When the polyfunctional vinyl monomer is used as a part of the copolymerized monomer, the preferable amount of the polyfunctional vinyl monomer is 5% by weight based on the total amount of all the monomers. It is as follows.

In order to obtain a resin dispersion for a coating agent, the presence of a carboxyl group copolymer-containing pinyl monomer and / or a hydroxyl group-containing vinyl monomer is necessary as a copolymer monomer with a macromonomer. In this case, the copolymerization ratio of each component is 1 to 50% by weight of the macromonomer, 1% of the carboxyl group-containing vinyl monomer and / or 1 hydroxyl group-containing vinyl monomer.
-30% by weight and 20-98% by weight of other copolymerizable vinyl monomers. When the proportion of the carboxyl group-containing vinyl monomer and / or the hydroxyl group-containing vinyl monomer is less than 1% by weight, the adhesion to the substrate is poor.

〔emulsifier〕

In the present invention, a monomer obtained by dissolving a macromonomer and an oil-soluble radical polymerization initiator in a comonomer using an emulsifier comprising a surfactant (A) or a surfactant (B) as an emulsifier. It is necessary to emulsify and disperse the solution in the micelles in an aqueous medium.

The emulsifying and dispersing is performed by mixing the emulsifier 0.3
５5 parts by weight and 30-100 parts by weight of water, and the mixture can be stirred by a homomixer, a homogenizer, an ultrasonic wave or the like.

The micelle particle size of the emulsified dispersion prepared by the above method is preferably as small as possible, and specifically, the average particle size is preferably 1 μm or less, more preferably 0.5 μm or less. When the particle size of the micelle is larger than 1 μm, the resin particle size in the obtained resin dispersion exceeds 1 μm, and as a result, the film formability is poor. For example, it is difficult to apply the resin dispersion as a coating agent and an adhesive. Limited use of the body.

In addition, the smaller the amount of the emulsifier used in the emulsification and dispersion, the better the physical properties such as water resistance of the obtained resin dispersion, and the preferred amount used in the present invention is 0.
3 to 3 parts by weight.

The resulting emulsified dispersion may be polymerized by raising the temperature as it is, but in view of easy control of heat generation during polymerization, the emulsified dispersion is dropped into a heated aqueous medium. It is preferred to polymerize and finally polymerize so as to obtain an aqueous resin dispersion having a solid content concentration of 20 to 70% by weight. As the polymerization temperature, it is possible to apply a temperature which has been conventionally generally applied in an emulsion polymerization method.
~ 90 ° C is preferred.

Next, the surfactant (A) used as the emulsifier in the present invention and the surfactant in the surfactant mixture (B) will be described in more detail.

The surfactant (A) is an alkali metal sulfosuccinate-based anionic surfactant as described above, and specific examples of such anionic surfactant include sodium di-2-ethylhexylsulfosuccinate and polycyclic phenyl. Examples thereof include sodium polyethoxysulfosuccinate, sodium polyoxyethylene alkyl allyl ether sulfosuccinate monoester, and sodium polyoxyethylene lauryl ether sulfosuccinate.

The surfactant (A) can be used alone as an emulsifier, but when used in combination with a nonionic surfactant having an HLB value of 10 or more, the emulsion stability of the aqueous emulsified dispersion during polymerization can be improved. Can be further improved.
Specific examples of the nonionic surfactant include a nonionic surfactant exemplified as a nonionic surfactant which is a constituent component of the surfactant (B) in the description of the surfactant (B) described below. There is.

The preferred mixing ratio of the surfactant (A) and the nonionic surfactant is 10 to 90% by weight to 90 to 10% by weight, and more preferably 10 to 40% by weight to 90 to 60% by weight. .

Next, among the anionic surfactants constituting the surfactant (B), as the sulfonic acid alkali metal salt-based anionic surfactants other than the above (A), alkyl benzene sulfonic acids such as sodium dodecyl benzene sulfonate are used. Alkali metal salts, sodium alkyl naphthalene sulfonate, alkali metal salts of sodium alkyl diphenyl ether disulfonate and naphthalene sulfonic acid formalin condensate, and the like.Also, as the sulfate alkali metal salt-based anionic surfactant, sodium lauryl sulfate, Alkyl sulfate alkali metal salts such as sodium stearyl sulfate, polyoxyethylene alkylene ether sulfates such as sodium polyoxyethylene lauryl ether sulfate and sodium polyoxyethylene octyl phenyl ether sulfate. Potassium, and the like.

As the nonionic surfactant having an HLB value of 10 or more constituting the surfactant (B), commercially available Emulgen 910,
Emulgen 930, Emulgen 938 (all manufactured by Kao Corporation); N
ewcol 563, Newcol 566 (manufactured by Nippon Emulsifier Co., Ltd.); Nonal 210 (manufactured by Toho Chemical Co., Ltd.), etc .; polyoxyethylene nonylphenyl ether; Emulgen 810, Emulgen 840S (manufactured by Kao Corporation); Newcol 860, Newcol 804
[Manufactured by Nippon Emulsifier Co., Ltd.]; polyoxyethylene octylphenyl ether such as Nonal 210 (manufactured by Toho Chemical Co., Ltd.), rheodol TW-L20, and rheodol TW-S120 [manufactured by Kao Corporation]; Newcol25, Newcol65 Polyoxyethylene sorbitan monoalkylate, polyethylene glycol stearate and polyoxyethylene cetyl ether such as Zorbone T-20 and Zorbone T-60 (all from Toho Kagaku). No.

When a nonionic surfactant having an HLB value of less than 10 is used as a component of the surfactant (B), the stability of the aqueous emulsified dispersion during polymerization is poor, and the emulsion polymerization cannot be carried out smoothly. The preferred ratio of the anionic surfactant to the nonionic surfactant in the surfactant (B) is from 10 to
90% by weight to 90 to 10% by weight, more preferably 10%
-40% by weight versus 90-60% by weight.

In addition, the emulsifier to be used may contain a surfactant other than the above surfactant.

(Polymerization initiator)

The polymerization initiator in the present invention is an oil-soluble radical polymerization initiator having a solubility in water at 20 ° C. of 10% by weight or less. As a preferred polymerization initiator, an azo-based initiator is AIBN, that is, 2,2. '-Azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutyrate, 4,4 ′
-Azobis-4-cyanovaleric acid and the like; among organic peroxides, lauroyl peroxide, benzoyl peroxide, dicumyl peroxide, cyclohexanone peroxide, di-n-propylperoxy carbonate, t-
A radical polymerization initiator such as butyl peroxypivalate having a solubility in water at 20 ° C. of 1% by weight or less is exemplified.

The amount of the polymerization initiator to be used is preferably 0.1 to 10% by weight, preferably 0.5 to 10% by weight, based on the total amount of the macromonomer and the comonomer.
5% by weight is more preferred. When the amount of the polymerization initiator is less than 0.1% by weight, the emulsion polymerization is difficult to proceed smoothly, and the macromonomer or the copolymerizable monomer tends to remain unreacted. When the amount exceeds 10% by weight, the molecular weight of the produced graft polymer is small. The use of the resulting aqueous dispersion is limited.

In the present invention, the polymerization initiator is added to the polymerization system in a state of being emulsified and dispersed together with the macromonomer and the copolymerization monomer as described above. According to the method, the resulting aqueous resin dispersion contains a large amount of unreacted macromonomer and unreacted comonomer.

(How to use as coating agent)

When the aqueous resin dispersion obtained by the present invention is used as a coating agent, a film-forming aid, a pigment, a filler, and the like can be added as necessary.

Examples of the film-forming aid include a plasticizer-type film-forming aid such as dioctyl phthalate, tricresyl phosphate and dibutyl phthalate, and butyl cellosolve, butyl cellosolve acetate, carbitol, carbitol acetate and butyl carbitol acetate. A film-forming aid can be used, and its preferred amount is 0.1 to 10% by weight based on the aqueous resin dispersion.

The aqueous resin dispersion for coating can be applied to a substrate as it is or after thickening by a known method, using a method such as a roll coater or a spray.

(C) Effects of the Invention According to the present invention, a macromonomer can be stably emulsified and dispersed in fine micelles by using a small amount of an emulsifier.
An aqueous resin dispersion having a small emulsifier content can be obtained, and the resin dispersion has an excellent effect that the graft polymer content is high and the amount of unreacted macromonomer is small.

Therefore, the aqueous resin dispersion obtained by the method of the present invention has a very wide range of uses, that is, coating agents such as pressure-sensitive adhesives, adhesives, pigments and coating agents, dispersion improvers such as pigments and fillers, antistatic agents and resin modification. It is suitably used for applications such as agents.

In particular, the carboxyl group-containing vinyl monomer and / or hydroxyl group-containing vinyl monomer as an essential component,
A coating agent comprising an aqueous resin dispersion obtained by copolymerizing a specific monomer has an effect of forming a coating film having extremely excellent gloss and blocking resistance.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, "part" in each example means "part by weight".

Example 1 To a mixture of 160 parts of methyl methacrylate (hereinafter, referred to as MMA) and 40 parts of butyl acrylate (hereinafter, referred to as BA),
One-sided methacryloyl-based styrene / acrylonitrile copolymer macromonomer (AN manufactured by Toagosei Chemical Industry Co., Ltd.)
-6, 50 parts of number average molecular weight Mn about 6000) and 3 parts of AIBN are dissolved, and this mixture is treated with 5 parts of sodium di-2-ethylhexylsulfosuccinate (2 parts per 100 parts of all monomers)
Was emulsified in 90 parts of deionized water using a homomixer to prepare an aqueous emulsified dispersion (hereinafter referred to as pre-emulsion).

The particle size of the obtained pre-emulsion was measured with a laser diffraction type particle size distribution analyzer (LA-500, manufactured by HORIBA, Ltd.). As a result, the average particle size was 0.44 μm. Met.

Using the whole amount of the above pre-emulsion, polymerization was carried out by the following method.

In a flask equipped with a stirrer, thermometer and condenser, 250 parts of deionized water and 1.5 parts of pre-emulsion are charged, and the internal temperature is kept at 80 ± 1 ° C. while bubbling nitrogen. Then, while stirring, 346.5 parts of the remaining pre-emulsion was added dropwise over 4 hours, and the reaction was continued for another 2 hours to complete the polymerization. During the polymerization, except that the aggregates slightly adhered to the wall of the flask, no separation or blocking occurred, and the polymerization was stable.

When the obtained emulsion polymer was filtered through a 200-mesh net, the grid amount was 0.1 part or less. The total amount of unreacted monomers measured by gas chromatography was 1% or less, the number average molecular weight Mn of the produced polymer was 108,000 in terms of polystyrene measured by gel permeation chromatography, and the weight average molecular weight Mw was 10%.
The conversion was 57,000, and the conversion of the macromonomer was 66%. The average particle size of the obtained polymer was 0.42 μm, and the distribution was narrow. The conversion rate of the macromonomer represents the ratio of the amount of the macromonomer actually polymerized to the amount of the macromonomer subjected to the polymerization,
It can be measured by gel permeation chromatography.

Examples 2 to 6 Emulsion polymerization was carried out in the same manner as in Example 1 except that the macromonomer described in Table 1 was used, to produce an aqueous resin dispersion. The results are as shown in Table 1.

Incidentally, the grid amount in the table is the total monomer mixture 250 consisting of the macromonomer and the copolymerized monomer subjected to the emulsion polymerization.
This is the amount of grid generated per copy, and the same applies to Table 2 and thereafter.

Examples 7 to 8 Emulsion polymerization was carried out in the same manner as in Example 1 except that the emulsifiers in Table 2 were used, and the results shown in Table 2 were obtained. In addition, all the pre-emulsions had stability of 1 day or more.

Examples 9 to 12 Emulsion polymerization was carried out under the same conditions as in Example 1 except that 2 parts of an anionic emulsifier shown in Table 3 and 4 parts of a polyoxyethylene nonylphenyl ether nonionic emulsifier having a different HLB were used. Were obtained. In these examples, the stability of each pre-emulsion and the stability during polymerization were good.

Example 13 and Comparative Example 5 The above-mentioned AN-6 was used as a macromonomer, and MMA, BA and methacrylic acid (hereinafter referred to as MAA) as copolymer monomers.
And the mixture was subjected to emulsion polymerization at the following copolymerization ratio by the following method.

AN-6 / MMA / BA / MAA = 100/100/45/5 (parts) As an emulsifier, 3 parts of sodium nonylphenoxypolyethoxyethanol sulfate used by Joseph P. Kennedy et al. The polymerization was carried out in the same manner as in Example 1 except that the polymerization was carried out (Comparative Example 5).

On the other hand, polymerization was carried out in the same manner as in Example 1 except that 4 parts of polyoxyethylene noniphenyl ether of HLB 18.5 was used together with 3 parts of sodium nonylphenoxypolyethoxyethanol sulfate as an emulsifier (Example 1).
3).

The properties of the aqueous resin dispersions obtained in Example 13 and Comparative Example 5 were as shown in Table 4.

Example 14 1.5% by weight of lauroyl peroxide as a polymerization initiator
The emulsion polymerization was carried out in the same manner as in Example 1 except that The properties and the like of the obtained aqueous resin dispersion were as follows.

Grid amount (parts): 0.1 or less, conversion ratio of macromonomer (%); 73, average particle size (μm) of resin dispersion; 0.36, number average molecular weight Mn = 255,000, weight average molecular weight Mw = 2108,000 Example 15 Polymerized in an aqueous medium in the same manner as in Example 1 except that 70 parts of MMA, 130 parts of BA, 6 parts of methacrylic acid, and 50 parts of a macromonomer AA-6 manufactured by Toagosei Chemical Industry Co., Ltd. were used. An aqueous resin dispersion having a diameter of 0.39 μm was obtained.

After thickening the obtained aqueous resin dispersion with an alkali-soluble polyacrylic acid-based thickener, apply it to a glass plate with a bar coater so that the film thickness after drying becomes 50 μm, and then dry. A coating was formed.

Then, the following physical properties were measured for the coating film, and the results are shown in Table 5.

Gloss: Measures 60 specular gloss according to JIS K5400.

Blocking resistance: The surfaces of the coating films formed on the glass plate were combined, a load of 150 g / cm ² was applied, the plate was allowed to stand in an atmosphere of 45 ° C. and 90% relative humidity for 24 hours, and then the test pieces were separated separately. Based on the state of the test piece at the time of the evaluation, the following evaluation was made.

◎: Does not adhere ○: Adheres, but the coating film does not peel off from the glass surface ×: Adheses, and the coating film peels off from the glass surface in a dot-like manner Scratch resistance: A weight is placed on the loading tray using a drawing tester manufactured by Ueshima Seisakusho , A continuous circle was drawn on the coating film with a steel needle attached thereto, and evaluated as follows.

◎: Marks of needles are hardly adhered ○: Marks of needles remain slightly △: Part of coating film falls off Adhesiveness: State of coating film when cellophane tape is adhered to coating film and quickly peeled off Based on the following, evaluation was made as follows.

：: The coating film surface and the cellophane tape are peeled off, and there is no change in the coating film. ：: 10% or less of the coating film surface adheres to the cellophane tape. X: The portion exceeding 10% of the coating film surface adheres to the cellophane tape. : The pencil hardness was measured for the product applied to the surface-treated steel plate and dried in the same manner as the glass plate.

Example 16 A solution prepared by mixing and dissolving a mixture of 80 parts of MMA, 120 parts of BA, and 40 parts of 2-hydroxyethyl methacrylate with 50 parts of macromonomer AS-650 manufactured by Toagosei Chemical Industry Co., Ltd. and 3 parts of AIBN was added to di-2- Emulsion polymerization was carried out under the same conditions as in Example 1 except that pre-emulsification was carried out with 4 parts of sodium ethylhexyl sulfosuccinate and 3 parts of a polyoxyethylene nonylphenyl ether-based nonionic emulsifier of HLB 18.9, and an average particle size of 0.36 μm Of a stable aqueous resin dispersion was obtained.

To the resulting dispersion, 10 parts of butyl cellosolve was added as a film-forming aid, and the mixture was sufficiently stirred at room temperature. Then, the viscosity was increased in the same manner as in Example 16, and the physical properties of the coating film were determined.

Example 17 A solution obtained by mixing and dissolving 30 parts of macromonomer AA-6; and 3 parts of AIBN in 60 parts of styrene, 160 parts of butyl methacrylate, and 15 parts of MAA was mixed with 8 parts of a commercially available 40% nonylphenoxypolyethoxyethanol sodium sulfate aqueous solution. Polymerization was carried out under the same conditions as in Example 1 except that the emulsion was pre-emulsified with 3 parts of polyoxyethylene nonylphenyl ether having an HLB of 17.2 to obtain a stable aqueous resin dispersion having an average particle size of 0.51 μm. In the same manner as in 16, the physical properties of the coating film were measured.

Comparative Example 6 Polymerization was carried out under the same conditions as in Example 16 except that 50 parts of styrene were used instead of the macromonomer AS-6. The average particle size of the obtained aqueous resin dispersion is 0.31 μm, and Mn is 1
Mw was 195,000.

To the aqueous resin dispersion, 10 parts of butyl cellosolve was added as a film-forming aid, and the mixture was sufficiently stirred at room temperature, and the physical properties of the coating film were measured in the same manner as in each of the above examples.

Comparative Example 7 Polymerization was carried out under the same conditions as in Example 17 except that 30 parts of MMA was used instead of macromonomer AA-6. The average particle size of the obtained aqueous resin dispersion is 0.44 μm, Mn is 93,000 Mw
Was 196,000.

The coating properties of the aqueous resin dispersion were measured in the same manner as in the above examples.

The measurement results of the coating film properties in Examples 15 to 17 and Comparative Examples 6 and 7 are as shown in Table 5 below.

Claims (1)

(57) [Claims] 1. A macromonomer having a radical polymerizable group and an oil-soluble radical polymerization initiator are dissolved in another vinyl monomer copolymerizable with the macromonomer. Aqueous resin dispersion characterized by emulsifying and dispersing in the presence of an emulsifier comprising activator (A) or (B), and then raising the temperature to copolymerize the macromonomer with another vinyl monomer. Manufacturing method. Surfactant (A); an alkali metal sulfosuccinate-based anionic surfactant. Surfactant (B) comprising an anionic surfactant of a sulfonic acid alkali metal salt or a sulfate ester alkali metal salt other than the above (A) and a nonionic surfactant having an HLB value of 10 or more. A surfactant containing the former in a proportion of 2 to 98% by weight and the latter in a proportion of 98 to 2% by weight based on the total amount of