JPH08188604A - Production of aqueous resin dispersion - Google Patents

Abstract

PURPOSE: To produce an aqueous resin dispersion being excellent in film-forming properties and flow and giving a coating film of good heat resistance by emulsion-polymerizing a radical-polymerizable unsaturated monomer in the presence of a dispersant being a low-molecular-weight copolymer prepared by using a surfactant having a radical-polymerizable unsaturation. CONSTITUTION: This dispersion is produced by polymerizing a radical- polymerizable unsaturated carboxylic monomer with other radical-polymerizable unsaturated monomers in water in the presence of a chain transfer agent and a surfactant having a radical-polymerizable unsaturation in the molecule to produce a copolymer of a number-average molecular weight of 500-20000, and emulsion-polymerizing a radical-polymerizable unsaturated monomer in the presence of a dispersant being the above copolymer. According to this process, the obtained dispersion has very excellent water resistance without detriment to film-forming properties and flow properties characteristic of a water-soluble resin. Further, it can be produced without using any solvent, a high-molecular- weight polymer being effective for developing water resistance and having good solvent resistance can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel resin aqueous dispersion which has the characteristics of both a water-soluble resin and a water-dispersible resin and is particularly excellent in fluidity, productivity and durability. The present invention relates to a method for producing an aqueous resin dispersion useful as a binder or an additive for paper processing, textile processing, adhesion, civil engineering, ink and other coating applications.

[0002]

2. Description of the Related Art In recent years, as environmental conservation measures such as improvement of working environment and strengthening of environmental regulations have become a social issue, demands for non-polluting resins have become stronger and stronger. Among them, since the water-based resin is a non-pollution type resin, there is an urgent need to switch from the solvent-based resin to the water-based resin for the purpose of environmental protection.

The method for producing an aqueous resin can be roughly classified into two types, one of which is polymerized by solution polymerization in a solvent and then phase inversion emulsified in water to remove the solvent, and the other of which is polymerized by emulsion polymerization. The product obtained by the former method has advantages such as film-forming property, good gloss, no emulsifier, and fluidity characteristics close to those of solution-type resin, but on the other hand, it does not require phase inversion emulsification and solvent removal steps. Therefore, there are drawbacks such as poor productivity and use of an organic solvent in the resin synthesis stage because the polymerization is carried out by solution polymerization.

On the other hand, in the case of a water-dispersible resin so-called emulsion resin synthesized by an emulsion polymerization method, it has a high molecular weight and is excellent in physical strength and durability, and it can be synthesized without using any organic solvent. Since it has no solvent step and has a high polymerization rate, it has advantages such as good productivity, but on the other hand, it has drawbacks such as poor film-forming property and poor gloss because it uses an emulsifier and is in a particle state. Further, the emulsion resin is characterized by having thixotropy. This property serves as an advantage for workability and sag, but on the other hand, serves as a drawback for thick coatability and leveling.

That is, although each of the water-soluble resin and the water-dispersible resin has its own characteristics, there are merits and demerits, and in the present situation, neither of them is sufficient in terms of conversion from a solvent resin to an aqueous resin.

Therefore, various studies have been made on the development of resins having both the characteristics of water-soluble resins and emulsion resins. For example, Japanese Unexamined Patent Publication (Kokai) No. 5-331408 discloses a technique relating to a resin aqueous dispersion having good durability by emulsion polymerization using an aqueous resin containing a silyl group and a carboxyl group obtained by solution polymerization as a dispersant. There is.

Further, Japanese Patent Laid-Open No. 6-145262 discloses a technique of synthesizing an alkali-insoluble polymer in the presence of an acid-functional alkali-soluble resin to obtain an aqueous resin.

[0008]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
The resin aqueous dispersion described in Japanese Patent Publication No. 331408/1993 is
Since the dispersant polymer is synthesized in a water-soluble solvent, it is necessary to use a large amount of solvent that has recently been strictly regulated, and in addition, there is a problem that productivity is poor because a solvent removal step is required. Was.

The aqueous resin obtained by the method described in JP-A-6-145262 gives a resin having a relatively high molecular weight and a good film-forming property. Since an emulsifier is used in the production of the functional alkali-soluble resin, the physical properties due to the emulsifier, that is, water resistance,
The problem remains that the film forming property is poor. In addition, a method of copolymerizing an amino group-containing unsaturated monomer has been proposed in order to improve water resistance, but the amino group-containing unsaturated copolymer has many restrictions on polymerization conditions, and the polymerization stability is also high. Since it is bad, it can be applied only under quite limited conditions, and there was a problem of yellowing.

The problem to be solved by the present invention is to provide a method for producing an aqueous resin dispersion, which has extremely high productivity, good resin fluidity characteristics, excellent film-forming properties, and extremely excellent water resistance. Especially.

[0011]

In view of these circumstances, the present inventors have made extensive studies in order to obtain a novel water-based resin having both the characteristics of a water-soluble resin and an emulsion resin and having good water resistance. As a result, a water-soluble resin and an emulsion resin are obtained by emulsion-polymerizing a radical-polymerizable unsaturated monomer using a surfactant having a radical-polymerizable unsaturated bond and a low-molecular weight polymer polymerized in water as a dispersant. In other words, the water-soluble resin has a good film-forming property, and the emulsion resin has a good productivity and a high molecular weight. It has been found that a novel water-based resin having a flow characteristic close to that of the above and having excellent water resistance can be obtained, and the present invention has been completed.

That is, in the present invention, the radically polymerizable unsaturated monomer (A) containing a carboxyl group and the other radically polymerizable unsaturated monomer (B) are radically polymerizable in water in the presence of a chain transfer agent. Polymerization is performed using a surfactant having an unsaturated bond in the molecule to produce a copolymer (C) having a number average molecular weight of 500 to 20,000, and then radical polymerization is performed using the copolymer (C) as a dispersant. The present invention relates to a method for producing an aqueous resin dispersion, which comprises emulsion-polymerizing a polar unsaturated monomer (D).

In the present invention, the polymerization of the carboxyl group-containing radical-polymerizable unsaturated monomer (A) and the other radical-polymerizable unsaturated monomer (B) can be carried out by emulsion polymerization. The conditions are not specified. In some cases, it is possible to use an organic solvent together, but it is preferable not to use it from the viewpoint of solvent regulation, and if it is unavoidable, the amount should be limited to the minimum necessary amount.

In the polymerization of the copolymer (C), a surfactant having a radical polymerizable unsaturated bond in the molecule (hereinafter, simply referred to as "reactive surfactant") is used from the viewpoint of water resistance. However, the reactive surfactant is not particularly limited as long as it has a radical polymerizable unsaturated bond in the molecule.

Specific examples of the reactive surfactant include sodium vinyl sulfonate, sodium styrene sulfonate, polyoxyethylene ammonium sulfate acrylate,
Methacrylic acid polyoxyethylene sulfonate sodium, polyoxyethylene alkenyl phenyl ammonium sulfonate, polyoxyethylene alkenyl phenyl sulphate sodium, sodium allyl alkyl sulfosuccinate,
There are anionic reactive emulsifiers such as sodium methacrylic acid polyoxypropylene sulfonate, and nonionic reactive emulsifiers such as polyoxyethylene alkenyl phenyl ether and polyoxyethylene methacryloyl ether.

In addition, generally commercially available reactive emulsifiers such as Aqualon HS-10, New Frontier A-229E (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Adecaria Soap SE-3N, SE-5N, SE-10N, SE
-20N, SE-30N (all manufactured by Asahi Denka Co., Ltd.),
Antox MS-60, MS-2N, RA-1120,
RA-2614 (manufactured by Nippon Emulsifier Co., Ltd.), Eleminol JS-2, RS-30 (manufactured by Sanyo Chemical Industry Co., Ltd.)
Manufactured), Latemur S-120A, S-180A, S-18
0 (above Kao Co., Ltd.) and other anionic reactive surfactants, Aqualon RN-20, RN-30, RN-50,
New Frontier N-177E (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), ADEKA REASOAP NE-10, NE-2
0, NE-30, NE-40 (above Asahi Denka Co., Ltd.)
Manufactured), RMA-564, RMA-568, RMA-11
14 (all manufactured by Nippon Emulsifier Co., Ltd.), NK ester M-2
Nonionic reactive surfactants such as 0G, M-40G, M-90G and M-230G (all manufactured by Shin-Nakamura Chemical Co., Ltd.) as long as they are generally used in emulsion polymerization reaction. It can be used without any problems. Of course, it is also possible to use commercially available reactive emulsifiers other than these.

Among these reactive surfactants, anionic reactive emulsifiers are preferable from the viewpoint of good dispersibility and polymerization stability, and anionic reactive emulsifiers are the main constituents from the viewpoint of emulsion stability. And partly
It is preferable to use a nonionic reactive emulsifier in combination.

The amount of the reactive surfactant used is not particularly limited, but is generally the amount used in emulsion polymerization, that is, the carboxyl group-containing radically polymerizable unsaturated monomer (A) and It is preferably 0.2 to 10 parts by weight per 100 parts by weight in total with the other radically polymerizable unsaturated monomer (B).

Further, in the polymerization of the copolymer (C),
Although it is possible to use an ordinary emulsifier having no unsaturated bond together with the reactive surfactant, it is preferable to keep the amount to the minimum necessary in consideration of various physical properties such as water resistance.

The emulsifier that can be used in combination is not particularly limited, but only representative ones are exemplified by sodium alkylbenzenesulfonate, sodium alkylsulfate, sodium dialkylsulfosuccinate, alkylphenyl polyoxyethylene sulfate soda salt or ammonium salt. And anionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene-polyoxypropylene block copolymers.

The use ratio of the carboxyl group-containing radically polymerizable unsaturated monomer (A) and the other radically polymerizable unsaturated monomer (B) used for the polymerization of the copolymer (C) is not particularly limited. It is not something that is done, but the total of both is 100
The content of the carboxyl group-containing radically polymerizable unsaturated monomer (A) is preferably 3 to 95 parts by weight, more preferably 3 to 50 parts by weight, based on parts by weight. That is, when the amount is 3 parts by weight or more, the function as a dispersion stabilizer becomes excellent,
Further, when the amount is 95 parts by weight or less, the effect of improving the fluidity of the water-soluble resin becomes good. Also, 3 to 50
By using the weight part, the balance of these characteristics becomes extremely good.

As the carboxyl group-containing radically polymerizable unsaturated monomer (A), any known one can be used. Typical examples are acrylic acid, methacrylic acid, maleic acid and phthalic acid. , Itaconic acid, crotonic acid, itaconic acid half ester, maleic acid half ester, and the like. Of course, it is possible to use these together.

The other radically polymerizable unsaturated monomer (B) copolymerizable with these is not particularly limited, and any generally used one can be used. Representative examples include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methacrylic acid such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate. Esters; Maleic acid, fumaric acid, itaconic acid esters; Vinyl acetate, vinyl propionate, tertiary vinyl carboxylate, and other vinyl esters; Aromatic vinyl compounds such as styrene and vinyltoluene; and vinylpyrrolidone Heterocyclic vinyl compounds; vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinylamide, etc .; vinylidene chloride, vinylidene fluoride, etc., vinylidene halide compounds; α-olefins such as ethylene, propylene, etc .; dienes such as butadiene. If desired, amides of α, β-ethylenically unsaturated acids such as acrylamide, methacrylamide, maleic acid amide, etc .; glycidyl group-containing monomers such as glycidyl methacrylate, allyl glycidyl ether; 2-hydroxyethyl methacrylate, etc. Hydroxyl group-containing monomer; Amino group-containing monomer such as dimethylaminoethyl methacrylate; Substituted amide of unsaturated carboxylic acid such as N-methylol acrylamide or methacrylamide, diacetone acrylamide; Containing unsaturated bond such as γ-methacryloxypropyltrimethoxysilane Silane compounds; monomers such as diallyl phthalate, divinylbenzene, allyl acrylate, trimethylolpropane trimethacrylate having two or more unsaturated bonds in one molecule You can Of course, it is possible to use these together.

Any chain transfer agent can be used as long as it has a chain transfer ability, and it is not particularly limited. Alkyl mercaptans such as octyl mercaptan, n-lauryl mercaptan, t-hexadecyl mercaptan, benzyl mercaptans such as benzyl mercaptan, dodecyl benzyl mercaptan, thiocarboxylic acids such as thioglycolic acid and thiomalic acid, or salts thereof, n-butylthio Thiocarboxylic acid alkyl esters such as glycolate and dodecyl-3-mercaptopropionate, nitrogen-containing thiols typified by monoethanolamine thioglycolate, and reactive functional group-containing mercaptans typified by trimethoxysilylpropyl mercaptan Etc. The.

Among these, hydrophobic chain transfer agents, such as alkyl mercaptans, are more preferable than hydrophilic chain transfer agents because they have more effective chain transfer ability.

The amount of the chain transfer agent varies depending on the polymerization conditions, the type of the monomer and the type of the chain transfer agent, but is 0.5 to 50 parts, preferably 1 to 20 parts by weight per 100 parts by weight of the radical-polymerizable unsaturated monomer. The use of parts by weight is preferable because the number average molecular weight of the copolymer (C) can be easily adjusted to 500 to 20,000.

The emulsion polymerization method in the production of the copolymer (C) can be carried out by a known method, and the conditions thereof are not particularly specified. For example, a carboxyl group-containing radically polymerizable unsaturated monomer can be used. In a total of 100 parts by weight of the monomer (A) and the other radically polymerizable unsaturated monomer (B),
A method in which a predetermined amount of a reactive surfactant, a chain transfer agent, a radical polymerization initiator of 0.1 to 5 parts by weight, and an aqueous medium of 50 to 1000 parts by weight are added and the temperature is raised to 40 to 90 ° C. under stirring to perform polymerization. Can be mentioned.

Further, 0.1 to 0.1 of the above radical polymerization initiator is used.
It can also be carried out by redox polymerization using 0.1 to 5 parts by weight of a reducing agent in combination with 5 parts by weight. At this time, a compound that generates a polyvalent metal salt ion such as iron ion or copper ion can be used together as an accelerator.

The radical polymerization initiator which can be used in the above reaction is not particularly limited, but persulfates such as potassium persulfate, ammonium persulfate and sodium persulfate, and azo such as azobisisobutyronitrile and its hydrochloride. Examples thereof include system initiators, peroxide initiators such as hydrogen peroxide, tertiary butyl hydroperoxide, cumene hydroperoxide, and the like.

Examples of reducing agents that can be used in combination with these radical initiators include sodium sulfoxylate formaldehyde, sodium pyrosulfite, and L-ascorbic acid. From the practical viewpoint, the solid content concentration during emulsion polymerization is preferably such that the final emulsion has a solid content concentration of 10 to 70% by weight, and the radical polymerizable unsaturated monomer, radical initiator, and Bulk charging of reducing agent,
It can be performed by a known technique such as continuous dropping and divided addition.

The copolymer (C) thus obtained is
The number average molecular weight needs to be in the range of 500 to 20,000. That is, if it is less than 500, the characteristics as a water-soluble resin are not easily exhibited, and if it exceeds 20,000, the function as a dispersant is deteriorated.

The method for measuring the number average molecular weight is not particularly limited, but it is a value obtained as a polystyrene conversion value by GPC measurement.

Since the copolymer (C) contains many hydrophilic groups,
Although it has a dispersibility even in a low pH range and can be used as a dispersant, the dispersibility is further improved by neutralizing with a basic substance. The copolymer (C) was added with a basic substance to obtain a pH =
It is preferable to use a neutralized to 7 or more as a dispersant.

Typical examples of the basic substance include inorganic bases such as sodium hydroxide, potassium hydroxide and borax, methylamine, isobutylamine,
Examples thereof include alkylamines such as triethylamine, alkanolamines such as dimethylethanolamine, and ammonia.

After the copolymer (C) is polymerized by the above method, emulsion polymerization of the radical-polymerizable unsaturated monomer (D) is subsequently carried out using the copolymer (C) as a dispersant.

This emulsion polymerization using the copolymer (C) as a dispersant can also be carried out by the above-mentioned known method. For example, 1 of the radical polymerizable unsaturated monomer (D) can be used.
A method in which a predetermined amount of the copolymer (C), 0.1 to 5 parts by weight of a radical polymerization initiator, and 50 to 1000 parts by weight of an aqueous medium are added to 00 parts by weight and the temperature is raised to 40 to 90 ° C. under stirring to perform polymerization. Is mentioned. In addition, as in the case of polymerizing the copolymer (C),
Redox polymerization in which 0.1 to 5 parts by weight of a reducing agent is used in combination with each of the above components may also be used.

Here, as the radical polymerization initiator and the reducing agent, any of those listed in the above-mentioned polymerization of the copolymer (A) can be used.

The radical-polymerizable unsaturated monomer (D) is not particularly limited, and examples thereof include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; methyl methacrylate. , Methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate; maleic acid, fumaric acid, itaconic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, and tertiary carboxylate vinyl Aromatic vinyl compounds such as styrene and vinyltoluene, Heterocyclic vinyl compounds such as vinylpyrrolidone; Vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinylamide, etc .; Vinylidene chloride, vinylidene fluoride, and other halogenated vinylidene compounds; Examples include α-olefins such as pyrene; dienes such as butadiene; and, if desired, amides of α, β-ethylenically unsaturated acids such as acrylamide, methacrylamide, maleic acid amide; glycidyl methacrylate, allylglycidyl. Glycidyl group-containing monomer such as ether; Hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate; Amino group-containing monomer such as dimethylaminoethyl methacrylate; N-methylolacrylamide or methacrylamide, substituted amide of unsaturated carboxylic acid such as diacetoneacrylamide ;
Unsaturated bond-containing silane compounds such as γ-methacryloxypropyltrimethoxysilane; monomers having two or more unsaturated bonds in one molecule such as diallyl phthalate, divinylbenzene, allyl acrylate and trimethylolpropane trimethacrylate. In addition, these monomers include acrylic acid, methacrylic acid, maleic acid, phthalic acid, itaconic acid, crotonic acid, itaconic acid half ester, maleic acid half ester, and other radically polymerizable unsaturated monocarboxylic groups. You may use a monomer together.

Further, radically polymerizable unsaturated monomer (D)
In the emulsion polymerization, the emulsion polymerization is preferably carried out without using any emulsifier other than the copolymer (C) from the viewpoint of water resistance, but an emulsifier may be used together. In this case, the emulsifier may be either a reactive emulsifier or an emulsifier having no unsaturated bond, but the above-mentioned reactive surfactant is particularly preferable from the viewpoint of improving water resistance and the like.

Here, as the reactive emulsifier and the ordinary emulsifier having no unsaturated bond, those generally used can be used, and specifically, sodium alkylbenzenesulfonate, sodium alkylsulfate, sodium dialkyl are used. Anionic emulsifiers such as sulfosuccinate, alkylphenyl polyoxyethylene sulfate soda salt or ammonium salt, nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene-polyoxypropylene block copolymer Etc.

The amount of the copolymer (C) used as the dispersant is not particularly limited, but preferably 5 to 1000 parts by weight per 100 parts by weight of the radically polymerizable unsaturated monomer (D). .

That is, when the amount is 5 parts by weight or more, the film-forming property, which is a characteristic of a water-soluble resin, becomes remarkably good, and when the amount is less than 1000 parts by weight, the water resistance effect as an emulsion resin is good. Becomes

The resin aqueous dispersion obtained by such a method is characterized in that it has a flow characteristic close to that of a solvent-based resin, that is, the viscosity does not change even if the shear is changed. Specifically, it satisfies the following conditions.

[0044]

[Equation 1] 0.5 ≦ η (6) / η (60) ≦ 3.0 η (6): Viscosity at 6 revolutions in B type viscometer η (60): At 60 revolutions in B type viscometer viscosity

The resin aqueous dispersion obtained by the present invention is extremely useful in consideration of conversion from solvent-based resin to aqueous resin, and is used for paints, paper processing, textile processing, adhesion, civil engineering, ink and other coating applications. It is possible to use it as a binder or an additive.

[0046]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. In addition, all the following parts and% are values based on weight.

Further, each evaluation test in Examples and Comparative Examples is based on the following evaluation method. [Evaluation method] Water resistance: 0.5 m thickness produced under room temperature and 7-day drying conditions
The film of m was immersed in tap water for 7 days, and the water absorption and whitening degree of the film were evaluated.

Evaluation of degree of whitening of film ◯: No whitening at all. Δ: White and pale, but transparent.

X: Completely cloudy.

Solvent resistance: A gel fraction was measured after a film having a thickness of 0.5 mm prepared under the conditions of drying at room temperature for 7 days was immersed in acetone for 24 hours.

Film-forming property: The transmittance at 640 nm of a film having a thickness of 0.5 mm produced under the conditions of drying at room temperature for 7 days was measured and evaluated according to the following criteria. ◯: 100 to 85% Δ: 84 to 50% X: 50
%Less than

Structural Viscosity: The viscosity at 6 revolutions (η (6)) and the viscosity at 60 revolutions (η (60)) measured with a B type viscometer were measured and calculated by the following formula. Structural viscosity = η (6) / η (60)

Weight average molecular weight: measured by GPC analysis in terms of styrene Solvent residual amount: measured by gas chromatography analysis

Example 1 (Preparation of Polymer for Dispersant) 218 parts of butyl acrylate (abbreviated as BA hereinafter), 82 parts of methyl methacrylate (abbreviated as MMA hereinafter), 80 parts of methacrylic acid (abbreviated as MAA hereinafter), γ-methacryl 20 parts of roxypropyltrimethoxysilane and 20 parts of n-lauryl mercaptan were used as a monomer mixture solution, and this mixture solution was ionized using 8 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd. reactive anionic emulsifier). A pre-emulsion was prepared by emulsifying in 104 parts of exchanged water.

A stirrer, a thermometer, and a cooler were attached.
A 2 liter reaction vessel was charged with 448 parts of ion-exchanged water, and the inside of the reaction vessel was heated to 80 ° C. while feeding nitrogen gas while stirring. After the temperature was raised, each of the pre-emulsion and 4 parts of potassium persulfate dissolved in 80 parts of ion-exchanged water was dropped into the reaction vessel after 3 hours. During the dropping reaction, stirring was continued while maintaining the temperature inside the reaction container at 80 ° C. After the dropping was completed, the mixture was stirred at 80 ° C. for 2 hours and then cooled and taken out. The obtained emulsion has a nonvolatile content of 40.2%, a viscosity of 12 cps, and a pH of 1.7.
Met. Further, the obtained polymer had a number average molecular weight of 7820 as measured by GPC in terms of polystyrene.

Example 2 (Production method 2 of polymer for dispersant) 218 parts of BA, 82 parts of MMA, 80 parts of MAA, 20 parts of γ-methacryloxypropyltrimethoxysilane and 20 parts of n-lauryl mercaptan were used as a monomer liquid mixture, The mixed solution was emulsified in 104 parts of deionized water using 4 parts of Hitenol N-08 (anionic emulsifier manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 4 parts of Aqualon HS-10 to prepare a pre-emulsion.

A stirrer, a thermometer, and a cooler were attached.
A 2 liter reaction vessel was charged with 448 parts of ion-exchanged water, and the inside of the reaction vessel was heated to 80 ° C. while feeding nitrogen gas while stirring. After the temperature was raised, each of the pre-emulsion and 4 parts of potassium persulfate dissolved in 80 parts of ion-exchanged water was dropped into the reaction vessel after 3 hours. During the dropping reaction, stirring was continued while maintaining the temperature inside the reaction container at 80 ° C. After the dropping was completed, the mixture was stirred at 80 ° C. for 2 hours and then cooled and taken out. The obtained emulsion has a nonvolatile content of 40.0%, a viscosity of 19 cps, and a pH of 1.7.
Met. The obtained polymer had a number average molecular weight of 7,150 as measured by GPC in terms of polystyrene.

Example 3 (Preparation Method 1 of New Emulsion) 144 parts of BA, 122 parts of MMA and 14 parts of γ-methacryloxypropyltrimethoxysilane were used as a monomer mixture liquid. In addition, 2 parts of potassium persulfate, 25% ammonia water 2
One part was dissolved in 120 parts of ion-exchanged water to obtain an initiator aqueous solution.

A stirrer, a thermometer, and a cooler were attached.
132 parts of ion-exchanged water in a 2-liter reaction vessel, Example 1
After charging 300 parts of the dispersant polymer produced by, the reaction vessel was charged with 92 parts of 6% ammonia water while stirring. Next, the temperature of the inside of the reaction vessel was raised to 80 ° C. with stirring while feeding nitrogen gas, and then the monomer mixed solution and the above-mentioned aqueous initiator solution were dropped into the reaction vessel over a period of 3 hours. The temperature in the reaction vessel was maintained at 80 ° C. with stirring during the dropping. After the dropping was completed, the mixture was kept at 80 ° C. for 2 hours with stirring, cooled, and taken out. The obtained emulsion had a nonvolatile content of 43.2%, a viscosity of 890 cps and a pH of 9.0.

Example 4 (Manufacturing Method 2 of New Emulsion) 144 parts of BA, 122 parts of MMA and 14 parts of γ-methacryloxypropyltrimethoxysilane were used as a monomer mixture liquid. In addition, 2 parts of potassium persulfate, 25% ammonia water 2
One part was dissolved in 120 parts of ion-exchanged water to obtain an initiator aqueous solution.

A stirrer, a thermometer, and a cooler were attached.
132 parts of ion-exchanged water in a 2 liter reaction vessel, Example 2
After charging 300 parts of the dispersant polymer produced by, the reaction vessel was charged with 92 parts of 6% ammonia water while stirring. Next, the temperature of the inside of the reaction vessel was raised to 80 ° C. with stirring while feeding nitrogen gas, and then the monomer mixed solution and the above-mentioned aqueous initiator solution were dropped into the reaction vessel over a period of 3 hours. The temperature in the reaction vessel was maintained at 80 ° C. with stirring during the dropping. After the dropping was completed, the mixture was kept at 80 ° C. for 2 hours with stirring, cooled, and taken out. The obtained emulsion had a nonvolatile content of 43.2%, a viscosity of 780 cps and a pH of 8.6.

Comparative Example 1 (Preparation Method 1 of Polymer for Comparative Dispersant) 218 parts of BA, 82 parts of MMA, 80 parts of MAA, 20 parts of γ-methacryloxypropyltrimethoxysilane, 20 parts of n-lauryl mercaptan were used as a monomer mixture liquid, and The mixed solution was emulsified in 104 parts of ion-exchanged water using 8 parts of Hitenol N-08 (anionic emulsifier manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) to prepare a pre-emulsion.

A stirrer, a thermometer, and a cooler were attached.
A 2 liter reaction vessel was charged with 448 parts of ion-exchanged water, and the inside of the reaction vessel was heated to 80 ° C. while feeding nitrogen gas while stirring. After the temperature was raised, each of the pre-emulsion and 4 parts of potassium persulfate dissolved in 80 parts of ion-exchanged water was dropped into the reaction vessel after 3 hours. During the dropping reaction, stirring was continued while maintaining the temperature inside the reaction container at 80 ° C. After the dropping was completed, the mixture was stirred at 80 ° C. for 2 hours and then cooled and taken out. The obtained emulsion had a nonvolatile content of 40.1%, a viscosity of 9 cps, and a pH of 1.7. The number average molecular weight of the obtained resin was 4520.

Comparative Example 2 (Production Method 1 of Comparative Emulsion) 144 parts of BA, 122 parts of MMA, and 14 parts of γ-methacryloxypropyltrimethoxysilane were used as a monomer mixture liquid. In addition, 2 parts of potassium persulfate, 25% ammonia water 2
One part was dissolved in 120 parts of ion-exchanged water to obtain an initiator aqueous solution.

With a stirrer, thermometer, and cooler attached
132 parts of ion-exchanged water in a 2 liter reaction vessel, Comparative Example 1
After charging 300 parts of the dispersant polymer produced by, the reaction vessel was charged with 92 parts of 6% ammonia water while stirring. Next, the temperature of the inside of the reaction vessel was raised to 80 ° C. with stirring while feeding nitrogen gas, and then the monomer mixed solution and the above-mentioned aqueous initiator solution were dropped into the reaction vessel over a period of 3 hours. The temperature in the reaction vessel was maintained at 80 ° C. with stirring during the dropping. After the dropping was completed, the mixture was kept at 80 ° C. for 2 hours with stirring, cooled, and taken out. The obtained emulsion had a nonvolatile content of 42.8%, a viscosity of 600 cps and a pH of 8.8.

Comparative Example 3 (Production Method 2 of Polymer for Comparative Dispersant) A mixture of 135 parts of BA, 57 parts of MMA, 51 parts of MAA and 13 parts of γ-methacryloxypropyltrimethoxysilane was used as a monomer mixture. In addition, 24 parts of t-butylperoxy 2-hexanoate was added to i-propanol 24
What was dissolved in 1 part was used as an initiator solution.

A stirrer, a thermometer, and a cooler were attached.
1150 parts of i-propanol was charged into a 5 liter reaction vessel, and the inside of the reaction vessel was heated to 80 ° C. with stirring while feeding nitrogen gas. Next, the monomer mixture solution and the initiator solution were added dropwise over 4 hours. The temperature inside the container was maintained at 80 ° C. with stirring during the dropping. After the dropwise addition was completed, the mixture was maintained at 80 ° C. for 1 hour while stirring, and then 0.6 part of t-butylperoxy-2-hexanoate was added, and the mixture was kept under the same conditions for 6 hours to complete the reaction. 48 parts of 25% ammonia water and 10 parts of ion-exchanged water were added to the obtained resin solution.
00 parts were gradually added, and most of the i-
Propyl alcohol was removed to obtain an aqueous resin. The resulting aqueous resin has a nonvolatile content of 24.5%, a viscosity of 340 cps,
The pH was 7.4. The number average molecular weight of the obtained resin is 85.
It was 20.

Comparative Example 4 (Production Method 2 of Comparative Emulsion) 144 parts of BA, 127 parts of MMA and 14 parts of γ-methacryloxypropyltrimethoxysilane were used as a monomer mixture liquid. In addition, 2 parts of potassium persulfate, 25% ammonia water 2
One part was dissolved in 120 parts of ion-exchanged water to obtain an initiator aqueous solution.

A stirrer, a thermometer, and a cooler were attached.
34 parts of ion-exchanged water and 490 parts of the dispersant polymer prepared in Comparative Example 3 were charged in a 2 liter reaction vessel, and the temperature in the reaction vessel was raised to 80 ° C. with stirring, and then the monomer mixture and the above-mentioned solution were used. The initiator aqueous solution was added dropwise to the reaction container after 3 hours. While stirring, add 8 times in the reaction vessel.
It was kept at 0 ° C. After the dropping was completed, the mixture was stirred at 80 ° C. for 2 hours and then cooled and taken out. The obtained emulsion had a nonvolatile content of 42.9%, a viscosity of 830 cps,
The pH was 8.4.

Comparative Example 5 (Production Method 3 of Comparative Emulsion) 230 parts BA, 146 parts MMA, 20 parts methacrylic acid,
A mixed solution of 4 parts of γ-methacryloxypropyltrimethoxysilane was used as a monomer mixed solution, and 8 parts of this HS-10 was emulsified in 112 parts of ion-exchanged water to obtain a pre-emulsion. Also, ammonium persulfate 2
One part was dissolved in 60 parts of ion-exchanged water to obtain an initiator aqueous solution.

A stirrer, a cooler, and a thermometer were attached.
Charge 334 parts of ion-exchanged water into a 2 liter reaction vessel,
The temperature was raised to 80 ° C. with stirring while introducing nitrogen gas.
After the temperature was raised, 30 parts of the pre-emulsion and 13 parts of the initiator aqueous solution were charged into a reaction vessel and left for 20 minutes. Next, the remaining pre-emulsion and the remaining initiator aqueous solution were added dropwise into the reaction vessel, taking 3 hours each. The temperature in the reaction vessel was maintained at 80 ° C. with stirring during the dropping. 2 more after dropping
The mixture was kept at 80 ° C. with stirring for an hour, neutralized with 12% aqueous ammonia so as to have a pH of 8 to 9, and then taken out.
The obtained emulsion has a nonvolatile content of 43.8% and a viscosity of 69.
It was 0 cps and pH 8.4.

Comparative Example 6 (Preparation Method 4 for Comparative Emulsion) A 1.2-liter reaction vessel equipped with a stirrer, a cooler, and a thermometer was charged with 306 parts of i-propyl alcohol, and the mixture was stirred at 80 ° C. while sealing nitrogen gas. The temperature was raised to. After heating, BA 172 parts, MMA 110 parts, methacrylic acid 15
Part, γ-methacryloxypropyltrimethoxysilane 3
And 6 parts of t-butylperoxy 2-hexanoate was added dropwise over 4 hours. After completion of dropping, the mixture was kept at 80 ° C. for another hour, and then t-butylperoxy 2
-Add 2 parts of hexanoate, hold at 80 ° C with stirring for a further 10 hours and then cool to room temperature.

After cooling, 14 parts of 25% ammonia water and 860 parts of ion-exchanged water were gradually added, and most of i-propyl alcohol was removed by distillation under reduced pressure. The obtained resin has a nonvolatile content of 35.6%, a viscosity of 820 cps, and a pH.
It was 7.3.

The following table shows the results of examination of the water resistance, solvent resistance, film-forming property, structural viscosity, presence / absence of solvent used, and residual solvent amount of the emulsion obtained as described above.

[0075]

[Table 1]

[0076]

EFFECT OF THE INVENTION According to the production method of the present invention, it is possible to obtain an aqueous resin dispersion which is excellent in water resistance while maintaining the film-forming property and the fluidity characteristic which are characteristics of the water-soluble resin.

Further, since the production method of the present invention can be produced without using any solvent at all, a high molecular weight polymer effective for exhibiting the above-mentioned water resistance can be obtained and the solvent resistance is good. Become.

The resin water dispersion obtained in the present invention is a paint,
It is useful as a binder and additive for paper processing, textile processing, adhesion, civil engineering, and other coating applications.

Claims (4)

[Claims] 1. A radically polymerizable unsaturated bond of a carboxyl group-containing radically polymerizable unsaturated monomer (A) and another radically polymerizable unsaturated monomer (B) in water in the presence of a chain transfer agent. A copolymer (C) having a number average molecular weight of 500 to 20,000, which is polymerized by using a surfactant having
And then emulsion-polymerizing the radically polymerizable unsaturated monomer (D) using the copolymer (C) as a dispersant. 2. After the production of the copolymer (C), the carboxyl group contained in the copolymer (C) is neutralized with a basic substance, and then the radical polymerizable unsaturated monomer (D) is polymerized. The manufacturing method according to claim 1. 3. In the production of the copolymer (C), a total of 100 of the carboxyl group-containing radically polymerizable unsaturated monomer (A) and the other radically polymerizable unsaturated monomer (B).
The method according to claim 1 or 2, wherein the chain transfer agent is used in an amount of 1 to 50 parts by weight per part by weight. 4. A radically polymerizable unsaturated monomer (D) 100 in the polymerization of the radically polymerizable unsaturated monomer (D).
Polymerization is performed using the copolymer (C) in a ratio of 5 to 1000 parts by weight based on parts by weight.
Manufacturing method described in.