JP3216274B2 - New water-based resin manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a novel aqueous resin. More specifically, the present invention relates to a method for producing a novel aqueous resin obtained by combining polyvinyl alcohol and microgel.

[0002]

2. Description of the Related Art Polyvinyl alcohol has been widely used as a paper coating agent, an adhesive, a binder, etc., because it exhibits a strong adhesive force and forms a transparent and tough film.
However, polyvinyl alcohol has a problem that the aqueous solution has poor stability over time and has a large water absorption when formed into a film, and thus swells when brought into contact with water.

Further, a reaction product obtained by emulsion polymerization of an alkyl acrylate or the like in an aqueous solution containing polyvinyl alcohol is known. Such a reactant has the characteristics of polyvinyl alcohol and also has excellent stability over time. However, since the reaction product contains an emulsifier, the film has poor transparency, and also has poor water resistance, so that there is a problem that the film is whitened when brought into contact with water.

Japanese Patent Application Laid-Open No. Sho 62-177007 describes a method for producing a microgel obtained by polymerizing an alkyl acrylate or the like in the presence of a reactive emulsifier. Such a microgel dispersion has excellent stability over time, and also has good water absorption, water resistance, and transparency of the film. However, since the microgel is a three-dimensional crosslinked polymer, the film has a problem that it swells in a solvent and has a problem that the film is inferior in film-forming properties and a large number of network-like streaks and cracks are generated in the film.

[Problems to be solved by the invention]

An object of the present invention is to provide a novel aqueous resin having both the properties of polyvinyl alcohol and microgel and eliminating both disadvantages. That is, the present invention has good stability over time of the aqueous resin solution,
It is another object of the present invention to provide a novel method for producing a water-based resin which suppresses the water absorption of a film and is excellent in water resistance, transparency, film-forming properties and solvent resistance.

It is to be noted that simply mixing the aqueous solution of polyvinyl alcohol and the dispersion of the microgel increases the viscosity,
Lack of stability over time of aqueous resin solution due to phase separation,
Also, when forming a film, unevenness or turbidity occurs,
Only the exposure of both disadvantages impairs the performance of the resin.

[0007]

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies to find a novel aqueous resin. As a result, the present inventors emulsified a vinyl monomer in an aqueous solution containing polyvinyl alcohol. In the polymerization, when a specific reactive emulsifier was used as an emulsifier, it was found that polyvinyl alcohol and microgel could be reacted in some form, and a novel aqueous resin which completely solved the above problems was obtained. The invention has been completed.

That is, according to the present invention, when a radically polymerizable monofunctional vinyl monomer is emulsion-polymerized in an aqueous solution containing polyvinyl alcohol, two or more carbon-carbon double bonds in the molecule are used as an emulsifier. A method for producing a novel aqueous resin characterized by using a reactive emulsifier having, and an emulsion polymerization of a radically polymerizable monofunctional vinyl monomer and a polyfunctional vinyl monomer in an aqueous solution containing polyvinyl alcohol The present invention relates to a novel method for producing an aqueous resin, which comprises using, as an emulsifier, a reactive emulsifier having one or more carbon-carbon double bonds in a molecule.

The configuration of the present invention will be described below.

The polyvinyl alcohol used in the present invention is not particularly limited as long as it is water-soluble, but usually has a degree of polymerization of about 200 to 2500 and a degree of saponification of 75% to 1%.
00% partially or completely saponified is preferred.
Further, a modified polyvinyl alcohol having a functional group such as a carboxyl group, an acetoacetyl group, and an acetal group can also be used. Further, polyvinyl alcohol affects the film forming properties, solvent resistance, and water resistance of the resulting film, and the amount of polyvinyl alcohol used is appropriately determined in consideration of these properties. That is, the amount of the polyvinyl alcohol to be used is generally about 5 to 900 parts by weight, preferably 40 to 250 parts by weight, based on 100 parts by weight of the total amount of the vinyl monomer. If the amount is less than 5 parts by weight, the resulting aqueous resin film will have poor solvent resistance and film-forming properties, and if it exceeds 900 parts by weight, the resulting aqueous resin solution will have poor stability over time.

As the radical polymerizable monofunctional vinyl monomer of the present invention, it is preferable to use an alkyl (meth) acrylate and / or a styrene compound. As the alkyl (meth) acrylate, those having an alkyl group having 1 to 18 carbon atoms are preferable. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, ( Iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate and the like. Examples of the styrene-based compound include styrene, α-methylstyrene, and vinyl toluene. Each of these monofunctional vinyl monomers can be used alone or in combination of two or more. Among them, alkyl methacrylate and / or styrene are preferred because they do not involve side reactions during radical polymerization. System compounds are preferred.

The alkyl (meth) acrylate and / or styrene compound may be any of various anionic monofunctional vinyl monomers, cationic monofunctional vinyl monomers, and nonionic monofunctional vinyl monomers other than those described above. It can be used in combination with a monomer. Examples of anionic monofunctional vinyl monomers include acrylic acid, methacrylic acid, monocarboxylic acids such as crotonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid,
Dicarboxylic acids such as muconic acid, organic sulfonic acids such as vinyl sulfonic acid, styrene sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid; phosphoric acid-based vinyl monomers such as 2- (meth) acryloyloxyethyl acid phosphate; and These include sodium salts and potassium salts of these various organic acids. Dimethylaminoethyl (meth) is a cationic monofunctional vinyl monomer
Vinyl monomers having a tertiary amino group such as acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, or the like of inorganic or organic acids such as hydrochloric acid, sulfuric acid, and acetic acid. salts,
Or a vinyl monomer containing a quaternary ammonium salt obtained by reacting the tertiary amino group-containing vinyl monomer with a quaternizing agent such as methyl chloride, benzyl chloride, dimethyl sulfate or epichlorohydrin. Nonionic monofunctional vinyl monomers include (meth) acrylamide, (meth) acrylonitrile,
Hydroxy group-containing (meth) acrylates such as vinyl acetate, methyl vinyl ether, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and glycidyl (Meth) acrylate, N-methylol (meth) acrylamide, urethane acrylates,
Phosphate ester-based vinyl monomers such as diphenyl-2 (meth) acryloyloxyphosphate and the like are typical examples.

Further, in the present invention, a polyfunctional vinyl monomer can be used in addition to the above-mentioned monofunctional vinyl monomer. For example, bifunctional vinyl monomers include di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, methylene bis (meth) acrylamide, ethylene bis (Meth) acrylamide,
Bis (meth) acrylamides such as hexamethylenebis (meth) acrylamide, divinyl esters such as divinyl adipate and divinyl sebacate, allyl methacrylate, diallylamine, diallyldimethylammonium, diallyl phthalate, diallyl chlorendate,
Divinylbenzene and the like. Further, as the trifunctional monomer, 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanurate,
Triallylamine, triallyl trimellitate, N, N
-Diallylacrylamide and the like, and tetrafunctional vinyl monomers include tetramethylolmethanetetraacrylate, tetraallyl pyromellitate, N, N,
N ′, N′-tetraallyl-1,4-diaminobutane,
Tetraallylamine salts, tetraallyloxyethane and the like can be mentioned.

When a polyfunctional vinyl monomer is used, its amount is about 5 parts by weight or less, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the monofunctional vinyl monomer. is there. If the amount of the polyfunctional vinyl monomer exceeds 5 parts by weight, agglomeration occurs and it becomes difficult to obtain a high-concentration aqueous resin, which is not preferable.

In the production of the novel aqueous resin of the present invention, when only a monofunctional vinyl monomer is used, the reaction is carried out in the presence of a reactive emulsifier having two or more carbon-carbon double bonds in the molecule. Emulsion polymerization is essential.

The reactive emulsifier having a carbon-carbon double bond in the molecule is not particularly limited, and various reactive emulsifiers can be appropriately selected and used. Examples of such a carbon-carbon double bond include functional groups such as a (meth) allyl group, a 1-propenyl group, a 2-methyl-1-propenyl group, a vinyl group, an isopropenyl group, and a (meth) acryloyl group. Can be Specifically, a sulfosuccinate salt of a polyoxyethylene alkyl ether having at least two functional groups in a molecule, a sulfate salt of a polyoxyethylene alkyl ether having at least two functional groups in a molecule, And sulfosuccinate salts of polyoxyethylene alkylphenyl ether having at least two functional groups in the molecule. Further, an acidic phosphoric acid (meth) acrylate dispersant having at least two functional groups in a molecule, and an oligoester (meth) having at least two functional groups in a molecule
Examples include various types of acrylate phosphates or alkali salts thereof, and oligoester poly (meth) acrylates of polyalkylene glycol derivatives having a hydrophilic alkylene oxide group having at least two functional groups in the molecule. These commercial products include (trade name KAYAMER PM-2, manufactured by Nippon Kayaku Co., Ltd.) and (trade name New Frontier A-229).
E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (trade name: New Frontier N-250Z, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Among these, a reactive emulsifier having a (meth) acryloyl group as a carbon-carbon double bond is preferred.

The reactive emulsifier having two or more carbon-carbon double bonds in the molecule is one having one carbon-carbon double bond.
It may be a mixture containing a reactive emulsifier. However, the amount of the reactive emulsifier having one carbon-carbon double bond is preferably not more than about 60% by weight of the total amount of the reactive emulsifier. If it exceeds 60% by weight, a new aqueous resin having a sufficient three-dimensional crosslinked structure cannot be obtained.

Examples of the reactive emulsifier having one carbon-carbon double bond include JP-A-63-23725, JP-A-63-240931, and JP-A-62-104802.
Japanese Patent No. JP-A No. 2000-222, and (trade name KAYAMER PM
-1, Nippon Kayaku Co., Ltd.), (trade name SE-10N, Asahi Denka Kogyo Co., Ltd.), (trade name NE-10, Asahi Denka Kogyo Co., Ltd.), (trade name NE-20) , Asahi Denka Kogyo Co., Ltd.
(Product name NE-30, manufactured by Asahi Denka Kogyo Co., Ltd.),
(Trade name New Frontier N-117E, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), (trade name Aqualon RN-20, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), (trade name Aqualon HS-10, Daiichi Kogyo Pharmaceutical Co., Ltd.) Co., Ltd.), (trade name Eminol JS-2,
Commercially available products such as Sanyo Kasei Co., Ltd. (trade name Latemul S-120, manufactured by Kao Corporation) and (trade name Latemul S-180, manufactured by Kao Corporation) are listed as typical examples.
The carbon-carbon double bond of the reactive emulsifier having one carbon-carbon double bond preferably has a (meth) acryloyl group.

When a monofunctional vinyl monomer and a polyfunctional vinyl monomer are used for producing the novel aqueous resin of the present invention, one or more carbon-carbon double bonds are contained in the molecule. It is essential that the emulsion polymerization is carried out in the presence of a reactive emulsifier. Examples of the reactive emulsifier include those described above as the reactive emulsifier having two or more carbon-carbon double bonds and the reactive emulsifier having one carbon-carbon double bond.

The reactive emulsifier may be used in combination with a known anionic emulsifier or nonionic emulsifier to such an extent that the performance of the novel aqueous resin of the present invention is not adversely affected. Examples of the anionic emulsifier include long-chain sodium α-olefin sulfonate, alkyl diphenyloxyethylene alkyl aryl ether sulfate, and the like. Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene block polymer, And polyoxyethylene alkylphenyl ether.

The amount of the reactive emulsifier used is usually from 1 to 30 parts by weight based on 100 parts by weight of the total amount of the monofunctional vinyl monomer or 100% by weight of the total amount of the polyfunctional vinyl monomer. Parts by weight, preferably 3 to 1
It is preferable to use 5 parts by weight. If the amount is less than 1 part by weight, agglomerates are generated during the polymerization or the crosslink density becomes small and a sufficient gel structure cannot be formed. If the amount exceeds 30 parts by weight, the polymerization stability deteriorates and the polymerization becomes poor. Aggregates are formed or gelled with the passage of time, which is not preferable.

Next, a method for producing the novel aqueous resin of the present invention will be described. The method for producing the novel aqueous resin of the present invention may be performed by a known emulsion polymerization method. For example, a method in which the polyvinyl alcohol and water are charged and dissolved in a predetermined reaction vessel while heating, and then a reactive emulsifier and the vinyl monomer are charged and emulsified, a radical polymerization initiator is added, and the mixture is heated under stirring. I'll do it.
The method of dropping the vinyl monomer may be any of batch dropping and divided dropping. The solid concentration of the reaction system is usually about 10 to 50% by weight, preferably 15 to 30% by weight.
% By weight.

The pH at the time of polymerization is usually preferably in the range of about 3 to 9. The reaction temperature may be within the temperature range for activating the polymerization catalyst, and is usually about 40 to 90 ° C, preferably 50 to 80 ° C, and the reaction time is usually 30 minutes to 2 minutes.
Time is good.

Examples of the radical polymerization initiator include a persulfate such as potassium persulfate and ammonium persulfate, a water-soluble radical polymerization initiator such as hydrogen peroxide and an aqueous azo initiator, or the above-mentioned persulfate. Redox polymerization initiators in the form of a combination with a reducing agent such as sodium hydrogen sulfite, sodium thiosulfate and the like can be mentioned. In the present invention, it is particularly preferable to use a redox polymerization initiator. Usually, the amount of the initiator used is about 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the total amount of the vinyl monomers.
It is good to do.

At the time of the reaction, a transition metal ion is preferably added as a polymerization accelerator in order to make the obtained aqueous resin into ultrafine particles having transparency. Examples of the transition metal ion include a copper ion and the like. The transition metal ion concentration in the reaction system is usually about 1.0 × 10 ^{−8 to} 1.0 × 10 ⁻³ mol / L, preferably 1.0 × 10 ⁻⁸ mol / L. 10 ^{-7 to} 1.0 ×
It is used so that it may become 10 ^-5 mol / l. 1.0 ×
If it is less than 10 ^-8 mol / l, it is difficult to obtain ultrafine polymer, and if it is more than 1.0 × 10 ^-3 mol / l, the number of fine particles increases and aggregated particles are formed, It is not preferable because crosslinking is suppressed.

The average particle size of the novel aqueous resin thus obtained is usually fine particles of about 10 to 300 nm.
It is preferable to adjust the temperature to about 1000 cps (25 ° C.).

[0027]

According to the production method of the present invention, it is possible to provide a novel aqueous resin having both characteristics of polyvinyl alcohol and microgel, and at the same time, eliminating both disadvantages. That is, the aqueous solution of the novel aqueous resin obtained by the production method of the present invention has good stability over time, and suppresses the water absorption of the film, and has excellent water resistance, transparency, film forming properties and solvent resistance. Therefore, it can be used for applications such as barrier agents, fillers, and coating agents.

[0028]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples. Incidentally,% in each example is based on weight unless otherwise specified.

Example 1 A completely saponified polyvinyl alcohol having a polymerization degree of 1100 ( manufactured by Kuraray Co., Ltd.) was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube, a monomer dropping funnel and a thermometer.
Product name PVA110 or less, referred to as PVA110) 100
g of ion-exchanged water and 1,000 g of ion-exchanged water were stirred and dissolved while heating to obtain an aqueous solution. This aqueous solution is heated to 40 ° C.
After cooling, an aqueous solution of copper sulfate was added at a concentration of 2.5 × 10 −5 in the system.
It was added so as to be mol / liter. Then, an oligoester-based reactive emulsifier having two or more carbon-carbon double bonds in the molecule (trade name: New Frontier A-229)
E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and adjusted to pH 4 by adding 25% ammonia water to dissolve. Next, 100 g of a mixed monomer composed of butyl methacrylate, methyl methacrylate and glycidyl methacrylate (weight mixing ratio is 39: 59: 2 in order) is added, and a constant speed (25
(0 ± 10 rpm). The temperature was raised under a nitrogen stream, and at 60 ° C., a redox initiator consisting of equimolar amounts of potassium persulfate and sodium thiosulfate (concentration in the system: 6.0 ×
(10-3 mol / l) was added to initiate polymerization.
The reaction was carried out for 60 minutes so that the polymerization temperature did not exceed 80 ° C., to obtain an aqueous resin solution containing transparent fine particles. The obtained aqueous resin solution has a nonvolatile content of 15.0% and a viscosity of 450 cps (2
5 ° C.), pH 4.8, average particle size 129 nm (Pho
The measurement was performed using LPA-3000 / 3100 manufactured by tal. The same applies hereinafter. )Met.

Example 2 PVA 110 was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube, a monomer dropping funnel and a thermometer.
4 g and 1000 g of ion-exchanged water were charged and dissolved while stirring with heating to obtain an aqueous solution. Add this aqueous solution to 40
After cooling to ℃, an aqueous solution of copper sulfate was added at a concentration of 2.5 × 10 ⁻⁵
It was added so as to be mol / liter. Then, an oligoester-based reactive emulsifier having two or more carbon-carbon double bonds in the molecule (trade name: New Frontier A-229)
E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 25% ammonia water was added to adjust the pH to 4 and dissolved. Next, 42 g of a mixed monomer composed of ethyl acrylate, methyl methacrylate and glycidyl methacrylate (weight mixing ratio in the order of 39: 59: 2) was added, and a constant speed (250
(± 10 rpm). Raise the temperature under a nitrogen stream to 6
At 0 ° C., a redox initiator consisting of equimolar amounts of potassium persulfate and sodium thiosulfate (system concentration 6.0 × 1
0 ^-3 mol / l) to initiate polymerization. Then, polymerization was carried out while continuously dropping 158 g of the mixed monomer. The reaction was carried out for 60 minutes so that the polymerization temperature did not exceed 80 ° C., to obtain an aqueous resin solution containing transparent fine particles. The obtained aqueous resin solution has a nonvolatile content of 20.6% and a viscosity of 50%.
0 cps (25 ° C.), pH 3.7, average particle size 65 n
m.

Example 3 In Example 2, a sulfuric ester-based reactive emulsifier having one carbon-carbon double bond in the molecule (trade name: Aqualon HS-10, Daiichi Kogyo Seiyaku Co., Ltd.) was used as the reactive emulsifier.
1g of a phosphoric acid emulsifier (trade name: H-3051, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier
And a transparent monomer was used in the same manner as in Example 2 except that styrene, 2-ethylhexyl methacrylate and methyl methacrylate were used as mixed monomers (weight mixing ratio was 10:50:40 in order) and 1 g of divinylbenzene. An aqueous resin solution containing water-soluble fine particles was obtained. The resulting aqueous resin solution has a nonvolatile content of 20.5% and a viscosity of 550 cp.
s (25 ° C.), pH 4.8, and average particle size was 250 nm.

Comparative Example 1 In Example 1, 6.7 was used in place of the reactive emulsifier, instead of 6.7, a dialkyl sulfosuccinate ester soda salt (trade name: Neocol P, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., nonvolatile content: 75%). Was performed in the same manner as in Example 1 to obtain an aqueous resin solution.
The obtained aqueous resin solution has a nonvolatile content of 15.3% and a viscosity of 3
50 cps (25 ° C.), pH 4.7, average particle size 22
It was 0 nm.

Comparative Example 2 In Example 1, a phosphoric acid emulsifier (trade name: H-3051, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used instead of the reactive emulsifier.
An aqueous resin solution was obtained in the same manner as in Example 1 except that 2.5 g was used. The nonvolatile content of the obtained aqueous resin solution was 15.2.
%, Viscosity 300 cps (25 ° C.), pH 3.2, and average particle diameter was 64 nm.

Comparative Example 3 30 ion-exchanged water was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube, a monomer dropping funnel and a thermometer.
0 g and an aqueous solution of copper sulfate were added so as to have a concentration of 2.5 × 10 ⁻⁵ mol / l in the system. Then, an oligoester-based reactive emulsifier having two or more carbon-carbon double bonds in the molecule (trade name: New Frontier A-229E,
15 g of Daiichi Kogyo Seiyaku Co., Ltd.) was charged, and the pH was adjusted to 4 by adding 25% aqueous ammonia to dissolve. Next, 40 g of a mixed monomer composed of ethyl acrylate, methyl methacrylate and glycidyl methacrylate (weight mixing ratio in the order of 39: 59: 2) was added, and a constant speed (250 ± 1) was added.
(0 rpm). Raise the temperature under a nitrogen stream to 50 ° C
A redox initiator consisting of equimolar amounts of potassium persulfate and sodium thiosulfate (concentration in system: 6.0 × 10 ⁻³⁾
(Mol / liter) to initiate polymerization. Then, polymerization was carried out while continuously dropping 260 g of the mixed monomer. The reaction was carried out for 60 minutes so that the polymerization temperature did not exceed 80 ° C., to obtain an aqueous resin solution containing yellow-red transparent fine particles. The obtained aqueous resin solution had a nonvolatile content of 42.5%, a viscosity of 250 cps (25 ° C.), a pH of 3.3, and an average particle size of 51 nm.

Comparative Examples 4 and 5 The aqueous resin solution obtained in Comparative Example 3 and 10% PVA 11
The aqueous resin solution was prepared by mixing the aqueous solutions of No. 0 and 5/5 and 7/3, respectively, in a solid content weight ratio.

(Performance Evaluation) Examples 1 to 3 and Comparative Example 1
The aqueous resin solution obtained in 5 and the aqueous solution of PVA110 were subjected to the following tests. The results are shown in Table 1.

(1) Stability over time The aqueous resin solution was allowed to stand at room temperature for 3 months, and its appearance and changes in viscosity were observed. ：: No change in appearance and viscosity. Δ: There is no change in appearance, but there is a change in viscosity. ×: Phase separation or gelation occurred.

(2) Transparency and Film Forming of Film The aqueous resin solution was dried at room temperature on a Teflon glass under natural ventilation to form a film having a thickness of 2 mm, and its appearance was visually judged. ：: Transparent film, no crack. Δ: Opaque film, no crack. X: Non-uniform film (xa). Or the film has cracks (× b).

(3) Water Absorption and Water Resistance of the Film A 2 mm thick film obtained by drying the aqueous resin solution on a Teflon glass under natural ventilation at room temperature is cut into 1 cm square and immersed in water. Then, the time until the film was whitened and the water absorption when the film was whitened were examined. In addition, the time until whitening is the time until the printed film is brought into close contact with the printed type and the type cannot be confirmed, and the water absorption is determined by the following equation. Water absorption (%) = {(AB) / B} × 100 A: Sample weight when whitened B: Sample weight before immersion

(4) Solvent resistance A 2 mm thick film obtained by drying the aqueous resin solution on a Teflon glass under natural ventilation at room temperature is cut into 1 cm squares, immersed in benzene for 1 day, The change in appearance was observed. ：: No change. ×: Swelled.

[0041]

[Table 1]

Claims (4)

(57) [Claims] In an aqueous solution containing polyvinyl alcohol, when a radically polymerizable monofunctional vinyl monomer is emulsion-polymerized, carbon-carbon is used as an emulsifier in a molecule.
A method for producing a novel aqueous resin, comprising using a reactive emulsifier having two or more carbon double bonds. 2. In the emulsion polymerization of a radically polymerizable monofunctional vinyl monomer and a polyfunctional vinyl monomer in an aqueous solution containing polyvinyl alcohol, a carbon-carbon double bond in the molecule is used as an emulsifier. A method for producing a novel aqueous resin, comprising using a reactive emulsifier having at least one reactive emulsifier. 3. The method according to claim 1, wherein the monofunctional vinyl monomer is an alkyl (meth) acrylate and / or a styrene compound. 4. The method according to claim 1, wherein the amount of the polyvinyl alcohol used is 5 to 900 parts by weight based on 100 parts by weight of the total amount of the vinyl monomer.