JP3215329B2 - Method for producing aqueous resin dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aqueous resin dispersion for imparting aesthetics and weather resistance to a coating object such as a house.

[0002]

2. Description of the Related Art Conventionally, in order to protect the surface of a structure exposed to sunlight, wind and rain, a paint for forming a coating film covering the surface of the structure has been used. As such a paint, a paint containing an aqueous resin dispersion is often used because of its advantages such as non-polluting properties and good workability during use.

[0003] In recent years, in order to further improve various physical properties such as weather resistance, stain resistance, and water resistance of a paint containing the aqueous resin dispersion as a raw material, the aqueous resin dispersion has various hydrophilic properties. Attempts have been made to introduce components.

[0004] As a method for obtaining such an aqueous resin dispersion, for example, Japanese Patent Application Laid-Open No. Hei 7-118544 discloses an ethylenically unsaturated carboxylic acid and another monomer copolymerizable therewith. Discloses a method of emulsion-polymerizing a monomer mixture in the presence of a neutralized alkali-soluble polymer obtained by emulsion polymerization in an aqueous medium having an agent.

[0005]

However, according to the above-mentioned conventional method, when a large amount of a hydrophilic component is introduced into an aqueous resin dispersion, the polymerization stability in emulsion polymerization is poor, and a large amount of aggregates is generated during the polymerization. There is a problem in that. Also, even if an aqueous resin dispersion that is a copolymer is obtained, when the above composition is used in a coating, when the coating is dried to form a coating, the water resistance of the coating is extremely poor. Has problems.

Accordingly, the present invention provides a method for producing a coating composition comprising an aqueous resin dispersion, which can stably emulsify even if a large amount of a hydrophilic component is introduced so that a coating film having excellent appearance, water resistance and stain resistance can be formed. An object of the present invention is to provide a method for producing the aqueous resin dispersion which is polymerized and has excellent long-term storage stability.

[0007]

According to a first aspect of the present invention, there is provided a method for producing an aqueous resin dispersion, comprising: a polymerizable monomer (a) having a reactivity with an acidic group; And the monomer component (A) containing the polymerizable monomer (b) having an acidic group is emulsion-polymerized, and the monomer component (B) is neutralized in a state where at least a part of the acidic group is neutralized. , Pre-emulsifier with water
Pre-emulsion which is charged into the reaction system in the state of being emulsified
A method for producing an aqueous resin dispersion emulsion-polymerized by a method,
With respect to the total amount of the monomer component (A) and the monomer component (B)
Then , a polymerizable monomer (c) having a cycloalkyl group in an amount within the range of 10% by weight to 80% by weight is added to at least one of the monomer component (A) and the monomer component (B). It is characterized by doing.

According to a second aspect of the present invention, there is provided a method for producing an aqueous resin dispersion, wherein the polymerizable monomer (a) having reactivity with a nitrogen-containing functional group and / or an acidic group is used to solve the above-mentioned problems. And a monomer component (A) containing a polymerizable monomer (b) having an acidic group, which is emulsion-polymerized to neutralize at least a part of the acidic group, and polymerizes with a nitrogen-containing functional group. sex monomer the monomer component (B) comprising (d), pre-milk
Preemer to be injected into the reaction system after emulsification in water
A method for producing an aqueous resin dispersion which is emulsion-polymerized by a solution method, comprising : combining a monomer component (A) and a monomer component (B).
The polymerizable monomer (c) having a cycloalkyl group in an amount within the range of 10% by weight to 80% by weight based on the weight is added to the monomer component (A) and the monomer component (C). B) is added to at least one of them.

According to a third aspect of the present invention, there is provided a method for producing an aqueous resin dispersion, wherein the monomer component (B) further comprises a polymerizable monomer having a reactivity with the acidic group. It is characterized by containing the monomer (a).

The method for producing an aqueous resin dispersion according to the invention described in claim 4 is intended to solve the above-mentioned problems.
2. The method for producing an aqueous resin dispersion according to 2 or 3, wherein the polymerizable monomer (c) having a cycloalkyl group is
General formula (1)

[0011]

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(Wherein, R ₁ represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and Z represents a cycloalkyl group including those having a substituent).

According to the above production method, the use of the polymerizable monomer (c) having a cycloalkyl group provides excellent weather resistance, water resistance, and gloss to the coating film from the aqueous resin dispersion. It is possible to stably obtain an aqueous resin dispersion capable of imparting retention characteristics and durability.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The method for producing an aqueous resin dispersion according to the present invention comprises a monomer component (A) containing a polymerizable monomer (a) having reactivity with an acidic group and a polymerizable monomer (b) having an acidic group. ) Is a method for producing an aqueous resin dispersion in which the monomer component (B) is emulsion-polymerized in a state where at least a part of the acidic group is neutralized, the polymerizable polymer having a cycloalkyl group. In this method, an aqueous resin dispersion is obtained by adding the monomer (c) to at least one of the monomer component (A) and the monomer component (B).

Further, the method for producing an aqueous resin dispersion according to the present invention is characterized in that a polymerizable monomer (a) reactive with a nitrogen-containing functional group and / or an acidic group, and a polymerizable monomer having an acidic group. A monomer component (A) containing a polymerizable monomer (d) having a nitrogen-containing functional group is obtained by emulsion polymerization of the monomer component (A) containing the polymer (b) and neutralizing at least a part of the acidic group. A method for producing an aqueous resin dispersion in which a monomer component (B) is emulsion-polymerized, wherein a polymerizable monomer (c) having a cycloalkyl group is converted into a monomer component (A) and a monomer component (B). ) To obtain an aqueous resin dispersion.

The polymerizable monomer (a) having a reactivity with the nitrogen-containing functional group and / or acidic group is used to form an aqueous resin dispersion by a crosslinking reaction that reacts with the nitrogen-containing functional group and / or acidic group. It has a function of curing a coating film formed from a paint containing the same.

As the polymerizable monomer (a), specifically, for example, glycidyl (meth) acrylate, 2
Polymerizable monomers having an epoxy group such as methyl glycidyl (meth) acrylate and allyl glycidyl ether; polymerizable monomers having an aziridinyl group such as (meth) acryloylaziridine and 2-aziridinylethyl (meth) acrylate Body; polymerizable monomers having an oxazoline group such as 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline;

Among the polymerizable monomers (a) exemplified above, a polymerizable monomer having an epoxy group is more preferable because it has an effect of accelerating a crosslinking reaction. In addition, as the polymerizable monomer (a), only one type may be used, or two or more types may be used in combination.

The amount of the polymerizable monomer (a) used is the total amount of the monomer component (A) and the monomer component (B) (hereinafter referred to as monomer component (A + B)). ) Is preferably in the range of 0.1% by weight to 40% by weight.
More preferably, it is in the range of 5% by weight to 15% by weight. If the amount is less than 0.1% by weight, a part of the acidic group remains unreacted in a large amount and the crosslinking becomes insufficient, so that the water resistance, stain resistance, solvent resistance, and strength of the dried coating film decrease. Is not preferred. On the other hand, if it exceeds 40% by weight,
It is not preferable because the stability and the storage stability during the emulsion polymerization decrease.

Specific examples of the polymerizable monomer (b) having an acidic group include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid.
Unsaturated polycarboxylic acids such as fumaric acid and itaconic acid; polymerizable monomers having a carboxyl group such as partially esterified ethylenically unsaturated polycarboxylic acids such as monoethyl maleate and monoethyl itaconate; vinyl sulfone Polymerizable monomers having a sulfonic acid group such as acid, styrenesulfonic acid, and sulfo (meth) acrylate; 2- (meth)
Acryloyloxyethyl acid phosphate, 2-
Acidic phosphate ester-based polymerizable monomers such as (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, and 2-methacryloyloxyethylphenylphosphoric acid; and the like. As the polymerizable monomer (b), only one type may be used, or two or more types may be used in combination.

Among the polymerizable monomers (b) exemplified above, a polymerizable monomer having a carboxyl group is preferable.
Ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid are more preferred. Further, the polymerizable monomer (b) can be used as a part of the monomer component (B). However, when the produced aqueous resin dispersion is used as a paint, the water resistance of the dried coating film decreases. It is not preferable because it may occur.

The amount of the polymerizable monomer (b) used is not particularly limited, but is based on the amount of the monomer component (A + B).
It is preferably in the range of 0.1% by weight to 10% by weight, and more preferably in the range of 0.5% by weight to 5% by weight. When the amount is less than 0.1% by weight, the characteristics of the polymerizable monomer (b) are not exhibited, and the stain resistance of a dried coating film is undesirably reduced.

Specific examples of the monomer component (B) include styrene derivatives such as styrene, vinyltoluene, α-methylstyrene, chloromethylstyrene, styrenesulfonic acid and salts thereof; N-monomethyl (Meth) acrylamide derivatives such as (meth) acrylamide, N-monoethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, diacetone acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) ) is synthesized by the alcohol of the ester forming reaction of (meth) acrylic acid with C ₁ -C _18, such as butyl acrylate (meth) acrylic acid esters; (meth) -2-hydroxyethyl acrylate, (meth) 2-hydroxypropyl acrylate, (meth) acrylic acid and polypropylene Having a hydroxy group such as esters of calls or polyethylene glycol (meth)
Acrylic esters; ethyl (meth) acrylate-2-sulfonate and salts thereof, vinylsulfonic acid and its salts, vinyl acetate, (meth) acrylonitrile, (meth) acrylic acid and ethylene glycol, 1,3-butylene glycol (Meth) acrylates having two or more polymerizable unsaturated groups in the molecule, such as esters with polyhydric alcohols such as diethylene glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, pentaerythritol and dipentaerythritol : Vinyltrimethoxysilane, γ- (meth)
Unsaturated monomers having an organosilicon group such as acryloxypropyltrimethoxysilane, allyltriethoxysilane, and trimethoxysilylpropylallylamine; and vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride, divinylbenzene, diallyl Phthalate; 2-hydroxy-4- [3- (meth) acryloxy-2 obtained by reacting 2,4-dihydroxybenzophenone or 2,2 ′, 4-trihydroxybenzophenone with glycidyl (meth) acrylate -Hydroxypropoxy] benzophenone, 2,2'-dihydroxy-4- [3- (meth) acryloxy-2-hydroxypropoxy] benzophenone and other polymerizable ultraviolet-absorbing monomers; 4- (meth) acryloyloxy-2 ,
2,6,6-tetramethylpiperidine, 4- (meth)
Acryloylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,
2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2 6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acrylamino-2,2,6,6-tetramethylpiperidine,
-(Meth) acryloyl-4-cyano-4- (meth) acrylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-croto Noylamino-2,2
6,6-tetramethylpiperidine, 1-crotonoyl-
Polymerizable ultraviolet-stable monomers such as 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like. As the monomer component (B), only one type may be used, or two or more types may be used in combination. Further, the monomer component (B) can be used as a part of the monomer component (A).

A basic compound is used for the purpose of neutralizing at least a part of the acidic groups of the emulsion polymer obtained by the emulsion polymerization in the former stage. By neutralizing at least a part of the emulsion polymer, the polymerization stability in the emulsion polymerization is improved, and when the produced aqueous resin dispersion is used as a coating, the stain resistance of the dried coating film in the coating is reduced. Performance can be improved.

The basic compound is not particularly limited, and various conventionally known neutralizing agents can be used. Specifically, for example, alkali metal compounds such as sodium hydroxide and potassium hydroxide; calcium hydroxide,
Alkaline earth metal compounds such as calcium carbonate; ammonia; monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, etc. And water-soluble organic amines. Only one basic compound may be used, or two or more basic compounds may be used in combination. Among the basic compounds exemplified above,
Since low-boiling amines such as ammonia, monomethylamine, dimethylamine, and trimethylamine are scattered at room temperature or under heating, the stain resistance of a cured coating film in a paint containing an aqueous resin dispersion can be further improved. Preferably, ammonia is more preferable.

The amount of the basic compound to be used is preferably an amount which neutralizes the acidic group of the emulsion polymer obtained by the emulsion polymerization in the former stage to more than 50%, and is preferably in the range of 60% to 100%. More preferred. That is, neutralization corresponding to 0.6 mol to 1.0 mol per 1 mol of an acidic group such as a carboxyl group contained in the polymerizable monomer (b) is more preferable.

The polymerizable monomer (c) having a cycloalkyl group is not particularly limited, but may have the general formula (1)

[0028]

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(Wherein, R ₁ represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and Z represents a cycloalkyl group including those having a substituent). The body further improves various physical properties that give beautiful feeling such as long-term weather resistance, gloss retention, water resistance, and durability to the dried coating film of the paint obtained by adding the pigment to the aqueous resin dispersion. Is more preferable.

Specific examples of Z in the general formula (1) include monocyclic saturated hydrocarbon residues such as a cyclopentyl group, a cyclohexyl group, and a cyclododecyl group. The cycloalkyl group may have an alkyl group having 1 to 6 carbon atoms as a substituent. Specifically, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group , A tertiary butyl group,
Examples include a pentyl group and a hexyl group. Specific examples of the polymerizable monomer (c) exemplified above include, for example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, and tertiary butylcyclohexyl (meth) acrylate. As the polymerizable monomer (c), only one type may be used, or two or more types may be used in combination.

The amount of the polymerizable monomer (c) to be used is not particularly limited, but the monomer component (A +
It is preferably in the range of 5% by weight to 95% by weight, more preferably in the range of 10% by weight to 80% by weight, based on B). If the amount used is less than 5% by weight,
The properties possessed by the polymerizable monomer (c) are not exhibited, and the appearance, dryness, and weather resistance of a dried coating film become insufficient, which is not preferable. On the other hand, if it is used in an amount exceeding 95% by weight, the polymerization stability during emulsion polymerization deteriorates, and the long-term storage stability of the produced aqueous resin dispersion is undesirably reduced.

The polymerizable monomer (d) is a polymerizable monomer having a nitrogen-containing functional group such as an amino group (-NH ₂ , -NH, -N <) or a quaternary ammonium salt. More specifically, specifically, for example, ethylenically unsaturated monomers having an amino group such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate, diallyldimethylammonium chloride, diallyldiethylammonium chloride and the like a polymerizable monomer having a quaternary en mode salts thereof.

Among the polymerizable monomers (d) exemplified above, the polymerizable monomer having a nitrogen-containing functional group is dispersed in the aqueous resin by a crosslinking reaction that favorably reacts with the polymerizable monomer (a). It also has the function of curing the coating film from the body, further improving the stain resistance of the dried coating film of the paint containing the aqueous resin dispersion,
It is preferable because the balance between the water resistance and the stain resistance of the coating film can be further maintained. In the present invention, an aqueous resin dispersion having more excellent effects than before can be obtained without using the polymerizable monomer (d). However, it is preferable to use the polymerizable monomer (d).

The amount of the polymerizable monomer (d) used is from 0.1% by weight to 10% by weight based on the monomer component (A + B).
, And more preferably in the range of 1% by weight to 5% by weight. When the use amount is less than 0.1% by weight, the properties of the polymerizable monomer (d) are not exhibited, and the stain resistance when a dried coating film is formed may be insufficient. Absent. On the other hand, if it is used in an amount exceeding 10% by weight, the polymerization stability and the storage stability during the emulsion polymerization are reduced, and the water resistance of the dried coating film is not sufficient.

The above monomer component (A) and monomer component (B)
Is not particularly limited, but by weight ratio,
It is preferably in the range of 90:10 to 10:90, and more preferably in the range of 70:30 to 30:70 in consideration of polymerization stability and physical properties of the dried coating film.

The method of polymerizing the monomer component (A) and the monomer component (B) is not particularly limited, and various conventionally known emulsion polymerization methods can be employed. Examples of the emulsion polymerization method include a method of collectively polymerizing a polymerization initiator, water, and an emulsifier, and a polymerization method such as a so-called monomer dropping method and a pre-emulsion method. Further, it is also possible to carry out multi-stage polymerization such as seed polymerization, core-shell polymerization, and power feed polymerization to form a different-phase structure of the emulsion particles.

The reaction conditions may be set according to the composition of the monomer component (A) and the monomer component (B), and are not particularly limited. Specifically, for example, the reaction temperature is preferably in the range of 0 ° C to 100 ° C, and the reaction time is preferably in the range of 1 hour to 10 hours.
The emulsion polymerization is preferably performed in an atmosphere of an inert gas such as a nitrogen gas. Further, as long as the physical properties of the coating film of the aqueous resin dispersion are not deteriorated, a hydrophilic solvent may be further added, or other known emulsifiers and additives may be added.

The method for neutralizing at least a part of the acidic groups of the emulsion polymer obtained in the former emulsion polymerization with a basic compound is not particularly limited. It may be added to the monomer component (B), or may be added directly to the emulsion polymer obtained by the emulsion polymerization in the former stage. When the polymerizable monomer (d) is contained in a part of the monomer component (B), it is preferable to directly add the polymerizable monomer (d) to the emulsion polymer obtained in the previous emulsion polymerization. Water is usually used as the aqueous medium, and a hydrophilic organic solvent such as a lower alcohol or a ketone can be used in combination, if necessary.

The polymerization initiator is not particularly restricted but specifically includes, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane). Dihydrochloride, 4,4'-azobis (4-
Azo compounds such as cyanopentanoic acid); persulfates such as potassium persulfate; peroxides such as hydrogen peroxide, peracetic acid, benzoyl peroxide, di-t-butyl peroxide;
And the like. Of the above-mentioned polymerization initiators, it is preferable to use one or a mixture of two or more polymerization initiators that do not leave a sulfate group such as an azo compound or a peroxide.

The amount of the polymerization initiator used depends on the amount of the monomer component (A)
It may be set according to the composition of the monomer component (B), and is not particularly limited.
B) 0.01 to 5 parts by weight per 100 parts by weight is preferred.

The emulsifier is not particularly limited, and may be an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, a polymer surfactant, or the like. All surfactants can be used. Further, a polymerizable surfactant having one or more polymerizable carbon-carbon unsaturated bonds in a molecule can be used.

Specific examples of the anionic surfactant include alkali metal alkyl sulfates such as sodium dodecyl sulfate and potassium dodecyl sulfate; ammonium alkyl sulfates such as ammonium dodecyl sulfate; sodium dodecyl polyglycol ether sulfate; Sulfosinoate; alkali metal salts of sulfonated paraffins, alkyl sulfonates such as ammonium salts of sulfonated paraffins; fatty acid salts such as sodium laurate, triethanolamine oleate, triethanolamine aviate; sodium dodecylbenzenesulfonate, alkali phenol Alkyl aryl sulfonates such as alkali metal sulfates of hydroxyethylene; Ren sulfonate; naphthalenesulfonic acid-formalin condensate; dialkyl sulfosuccinate, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkylaryl sulfate salts.

Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether; polyoxyethylene alkyl aryl ether; sorbitan fatty acid ester; polyoxyethylene sorbitan fatty acid ester; glycerol monolaurate, and the like. Fatty acid monoglyceride; polyoxyethylene oxypropylene copolymer; and condensation products of ethylene oxide with aliphatic amines, amides or acids.

Specific examples of the above polymer surfactant include polyvinyl alcohol; sodium poly (meth) acrylate, potassium poly (meth) acrylate,
Ammonium poly (meth) acrylate, polyhydroxyethyl (meth) acrylate; polyhydroxypropyl (meth) acrylate; or a copolymer of two or more polymerizable monomers which are constituent units of these polymers or other Copolymers with monomers and the like can be mentioned. Further, phase transfer catalysts such as crown ethers exhibit surface activity, and may be used as a surfactant.

Examples of the polymerizable surfactant include, for example, sodium propenyl-2-ethylhexylbenzenesulfosuccinate, sulfate of polyoxyethylene (meth) acrylate, ammonium polyoxyethylene alkylpropenyl ether sulfate, and the like. ,
Anionic polymerizable surfactants such as phosphoric acid esters of polyoxyethylene (meth) acrylate; nonionics such as polyoxyethylene alkyl benzene ether (meth) acrylate and polyoxyethylene alkyl ether (meth) acrylate And a polymerizable surfactant. As these emulsifiers that are surfactants, only one type may be used, or two or more types may be used in combination.However, in consideration of the water resistance of the dried coating film from the aqueous resin dispersion, polymerization is performed. Nonionic surfactants are preferred.

The amount of the emulsifier used is not particularly limited.
The amount is preferably 0.1 to 50 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the monomer component (A + B).

The aqueous resin dispersion according to the present invention is such that only the emulsion polymer obtained by the above production method can be used as a coating material as it is. Also, in the aqueous resin dispersion,
Known additives as necessary, for example, a film-forming aid, a pigment,
A filler, a toner, a wetting agent, an antistatic agent, a pigment dispersant, a plasticizer, an antioxidant, an ultraviolet absorber, an ultraviolet stabilizer, a flow control agent, a viscosity modifier and the like may be added.

Examples of the above pigments include inorganic pigments such as white pigments such as titanium oxide, antimony trioxide, zinc white, lithopone, and lead white, carbon black, graphite, molybdenum red, red iron oxide, yellow iron oxide, and yellow flower. And azo compounds such as benzidine and Hansa Yellow, and phthalocyanines such as phthalocyanine blue. These pigments may be used alone or in combination of two or more.

As these pigments, it is preferable to use pigments having good weather resistance so as not to lower the weather resistance of the coating film. For example, when using titanium oxide which is a white pigment, it is preferable to use titanium oxide having a rutile structure rather than titanium oxide having an anatase structure from the viewpoint of improving the weather resistance of a coating film from an aqueous resin dispersion. Further, when using titanium oxide having a rutile structure, it is more preferable to use titanium oxide by chlorine than titanium oxide by sulfuric acid in order to exhibit long-term weather resistance of the aqueous resin dispersion.

The method for coating the coating material containing the aqueous resin dispersion of the present invention on the object to be coated is not particularly limited.
Conventionally known various coating methods can be adopted. Examples of the coating method include a roll coater, a gravi coater, a blade coater, a rod coater, an air knife coater, etc., and a spray. The object to be coated is not particularly limited, and examples thereof include paper; fibers and films of organic polymers such as polyethylene terephthalate, nylon and polyvinyl chloride; inorganic fibers such as glass fibers; rubber sheets and metal plates. Can be

[0051]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, “parts” indicates “parts by weight”.

(A) Polymerization stability The polymerization stability of the aqueous resin dispersion was evaluated by measuring the amount of aggregates. That is, the case where the amount of the aggregate is 0.010% by weight / to the monomer or less and the emulsion polymerization is very stable is “very good” (indicated by ◎ in Table 3), and the amount of the aggregate is 0.010% by weight. / When the emulsion polymerization is stable and the emulsion polymerization is stable (good, indicated by ○), when the emulsion polymerization is not possible due to the aggregates,
Polymerization was not possible "(same as above, indicated by x).

(B) Water whitening resistance test To 100 parts of the aqueous resin dispersion, 10 parts of butyl cellosolve (film forming aid) was added, and this was applied on a glass plate with an applicator, and dried to form a film. The thickness was about 30 μm. This coating film was heated at 23 ° C. and 65% RH
The test piece was immersed in deionized water at 23 ° C. for 1 day and 7 days under the conditions of Humidity) for 1 day and 7 days, respectively, and the degree of whitening of the coating film was visually observed.

The evaluation criteria for the degree of whitening of the coating film were four levels.
That is, "no abnormality" (indicated by ◎ in Table 4) when no change was observed on the surface of the coating film, and "slightly fluorescent color" when the surface of the coating film was fluorescent Show),
A case where the coating film surface has a pale fluorescent color on the whole was evaluated as “whole fluorescent color” (same as indicated by Δ), and a case where the coating surface was whitened was evaluated as “whiten” (same as indicated with ×). .

(C) Warm water whitening resistance test A test piece was prepared by repeating the same operation as the water whitening resistance test. The test pieces were immersed in warm water at 60 ° C. for 3 hours and 1 day, respectively, and the degree of whitening of the coating film was visually observed. The evaluation of the degree of whitening of the coating film was performed according to the same evaluation criteria as in the water whitening resistance test.

(D) Water Absorption Rate and Dissolution Test Method in Water The same operation as in the water whitening resistance test was repeated, and the resultant was applied on a Teflon plate with an applicator, and the thickness of the dried coating film was set to about 100 μm. A test piece was obtained by drying this coating film at 23 ° C. and 65% RH for 7 days. First, the test piece was cut into a square of about 20 mm and weighed (the weight at this time was W ₀ ). Next, the test pieces were immersed in deionized water for 1 day and for 7 days, respectively, and then lifted up, lightly wiped the surface of water, and weighed (the weight at this time was W ₁ ). The test piece immersed in deionized water for further 7 days was dried at 110 ° C. for 1 hour, allowed to cool, and weighed (the weight at this time was W ₂
And). The water absorption and the elution were determined by the following formulas.

Water absorption (%) = 100 · (W ₁ −W ₀ ) / W ₀ Elution rate (%) = 100 · (W ₀ −W ₂ ) / W ₀ (e) Weather resistance Consists of an aqueous resin dispersion. The weather resistance of the paint was evaluated by performing an accelerated weather resistance test. First, an aqueous resin dispersion was prepared as a white paint having the following composition.

Water 64.6 (parts) Special polycarboxylic acid type polymer surfactant (trade name, Demol EP, manufactured by Kao Corporation) 2.0 (parts) Nobuko 8034 (manufactured by Sannobco Corporation) 0.3 (parts) Part) Titanium oxide (rutile type) 60.0 (part) Aqueous resin dispersion 146.7 (part) 2,2,4-trimethylpentanediol-1,3-monoisobutyrate (trade name, CS-12, 9.5 (parts) 5% polyether thickener (trade name, Adecanol UH-420, manufactured by Asahi Denka Co., Ltd.) 1.0 (parts) Total 284.1 (parts) obtained The white paint was applied on a flexible board so as to have a dry film thickness of about 80 μm. The flexible board to which the white paint was applied was dried at 25 ° C. for one week to obtain a test piece. This test piece was subjected to an accelerated weathering resistance test, and the change in the coating film was represented by a gloss retention, and the weather resistance of the coating composed of the aqueous resin dispersion was evaluated.

(F) Water Resistance A test piece was prepared by repeating the same operation as in the accelerated weather resistance test. This test piece was immersed in water at 25 ° C. for 3 days, and the change in the state of the coating film was examined. The evaluation criteria for the water resistance of the coating film were three levels. That is, “good” (indicated by “○” in Table 5) when no change was observed on the coating film surface, and “slightly small swelling in the peripheral portion” when slight swelling was observed around the coating film surface. (Same as △), and the case where peeling was observed in the coating film was evaluated as “peeling in the coating film” (Same as ×).

(G) Stain resistance Stain resistance was evaluated by an outdoor exposure test method. That is, the same operation as the accelerated weathering test was first repeated to prepare a test piece. The contaminated material was dropped or adhered to the coating surface of the test piece, and after being left for one month, the contaminated material was wiped off. The degree of contamination on the surface of the coating film was visually inspected.

The evaluation criteria for the stain resistance of the coating film were four levels. That is, when no change is observed on the coating film surface, "dirt is not conspicuous" (indicated by ◎ in Table 5), and when the coating film surface is slightly dirt, "slight dirt is recognized".
(Same as ○), “Stain is recognized” when the surface of the coating film is observed (indicated by Δ), and “Stain is excessive” when the surface of the coating film is extremely high (Same as ×). ).

Example 1 A flask equipped with a dropping funnel, a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 65 parts of deionized water and 20% polyoxyethylene alkylphenylpropenyl ether sulfate ammonium salt as an emulsifier. Aqueous solution (trade name; AQUALON HS-1)
0, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 3.3 parts of a 20% aqueous solution of polyoxyethylene alkylphenylpropenyl ether (trade name: AQUALON RN-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) The temperature was raised to 75 ° C. with stirring while blowing nitrogen gas into the flask.

Next, 2-ethylhexyl acrylate 1
5 parts, glycidyl methacrylate 1 part, acrylic acid 1
Part, hydroxyethyl methacrylate 1 part, styrene 5
10 parts by weight of the polymerizable monomer component (A) consisting of 1 part, 12 parts of n-butyl methacrylate and 15 parts of cyclohexyl methacrylate were added to the flask.

To the remaining monomer component (A), 3.3 parts of 20% aqueous solution of Aqualon HS-10 and 20 parts of emulsifier were added.
1.7 parts of an aqueous solution of Aqualon RN-20% and 45 parts of deionized water were added to obtain a pre-emulsion mixture (I).

Subsequently, 0.6 part of a 5% aqueous solution of ammonium persulfate was added to the pre-emulsion mixture (I).
After 10 minutes, a pre-emulsion mixture (I) to which a 5% aqueous solution of ammonium persulfate was added and 2.4 parts of a 5% aqueous solution of potassium persulfate were uniformly added dropwise to the flask over 80 minutes. During the dropping, the temperature in the flask was kept at 75 ° C to 80 ° C. After the addition, the emulsion polymerization was completed while stirring at the same temperature for 30 minutes.

Next, 2-ethylhexyl acrylate 1
A polymerizable monomer component (B) comprising 4 parts, 1 part of glycidyl methacrylate, 1 part of hydroxyethyl methacrylate, 14 parts of styrene, 5 parts of n-butyl methacrylate, and 15 parts of cyclohexyl methacrylate was added with 25% as a basic compound. 0.8 parts of ammonia water, 5 parts of 20% aqualon HS-10 aqueous solution as emulsifier and 20%
Pre-emulsion mixture (II) containing 2.5 parts of Aqualon RN-20 aqueous solution and 65 parts of deionized water
Was adjusted.

The pre-emulsion mixture (II), 3.0 parts of a 5% aqueous potassium persulfate solution and 2.4 parts of a 2.5% aqueous sodium hydrogen carbonate solution were uniformly dropped into the flask over 100 minutes. During the dropping, the temperature in the flask was kept at 75 ° C to 80 ° C.

After completion of the dropwise addition, the emulsion polymerization was completed while stirring at the same temperature for 1 hour, and the solid content was 45% and the viscosity was 890 mPa · s.
Thus, an aqueous resin dispersion (1) of Example 1 was obtained. The composition of the monomer component (A) is shown in Table 1, and the composition of the monomer component (B) is shown in Table 2. The solid content of the aqueous resin dispersion (1) obtained by emulsion polymerization of these monomer components is shown. Table 3 shows the concentration, the amount of aggregates and the viscosity.

Various physical properties of the obtained aqueous resin dispersion (1) were measured or evaluated by the methods described above. As a result, the water whitening resistance was "no abnormality" after 1 day and 7 days, the warm water whitening resistance was "no abnormality" after 3 hours, "slightly fluorescent" after 1 day, and the water absorption was 1 day. 3.1 days later,
After 7 days, it was 6.0%, and the elution rate was 0.1%.
Table 4 shows the measurement results and evaluation of various physical properties of the aqueous resin dispersion (1).

Further, various physical properties of the white paint prepared from the obtained aqueous resin dispersion (1) were measured or evaluated by the methods described above. As a result, the gloss retention was greater than 95%, the water resistance was "good", and the stain resistance was "somewhat dirty".

Table 5 shows various physical properties and evaluations of the white paint produced from the aqueous resin dispersion (1).

Examples 2 to 7 The compositions of the monomer components in Example 1 are shown in Tables 1 and 2
The same operations as in Example 1 were repeated except that the conditions shown in (1) were used, to obtain aqueous resin dispersions (2) to (7). However, in Example 2, 25% was used as the basic compound.
Instead of mixing and adding aqueous ammonia to the monomer component, the aqueous solution was directly added to the flask. The composition of the monomer component (A) is shown in Table 1, the composition of the monomer component (B) is shown in Table 2, and the aqueous resin dispersions (2) to () obtained by emulsion polymerization of these monomer components. Table 3 shows the solid content concentration, the amount of aggregates, and the viscosity of 7). In Example 4, as emulsifiers, ammonium polyoxyethylene nonylphenyl ether sulfate (trade name: Hytenol N-08, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and polyoxyethylene nonyl phenyl ether (trade name: Nonipol 200) , Manufactured by Sanyo Chemical Industries, Ltd.).

Various physical properties of the obtained aqueous resin dispersions (2) to (7) were measured and evaluated by the methods described above.
Table 4 shows the measurement results and evaluations of various physical properties of the aqueous resin dispersions (2) to (7).

Further, the obtained aqueous resin dispersions (2) to
Various physical properties of the white paint prepared from (7) were measured or evaluated by the methods described above. Aqueous resin dispersion (2)-
Table 5 shows various physical properties and evaluations of the white paint produced from (7).
It described in.

[Comparative Examples 1] to [Comparative Example 2] In Example 1, the compositions of the monomer components are shown in Tables 1 and 2.
The same operation as in Example 1 was carried out, except that the conditions were as shown in the above, to obtain comparative aqueous resin dispersions (1) and (2). Table 1 shows the composition of the monomer component (A), and Table 2 shows the composition of the monomer component (B). The comparative aqueous resin dispersion (1) obtained by emulsion polymerization of these monomer components is shown. , And (2) are shown in Table 3.

Various physical properties of the obtained comparative aqueous resin dispersion (1) were measured and evaluated by the methods described above. Table 4 shows the measurement results and evaluations of various physical properties of the comparative aqueous resin dispersion (1).

Further, various physical properties of the white paint prepared from the obtained comparative aqueous resin dispersion (1) were measured or evaluated by the methods described above. Table 5 shows various physical properties and evaluations of the white paint produced from the comparative aqueous resin dispersion (1).
It described in.

In Comparative Example (2), the above-described various measurements and evaluations could not be performed because the polymerizability was poor and a polymer could not be obtained.

[0079]

[Table 1]

[0080]

[Table 2]

[0081]

[Table 3]

[0082]

[Table 4]

[0083]

[Table 5]

As is clear from the results of Examples 1 to 7 described in Tables 3 to 5, it is understood that the aqueous resin dispersion according to the present invention can maintain various physical properties during production for a long period of time. . That is, it is understood that the aqueous resin dispersion according to the present invention has excellent long-term storage stability. Further, the coating comprising the aqueous resin dispersion according to the present invention,
It is understood that the coating film is excellent in weather resistance, water resistance, stain resistance, stickiness, and gloss retention.

[0085]

According to the method of the present invention, it is possible to provide a method for producing an aqueous resin dispersion having excellent long-term storage stability and polymerization stability, and to provide a method for preparing an aqueous resin dispersion from a paint containing the aqueous resin dispersion. To obtain a water-based resin dispersion which can be quickly dried and hardened in the initial stage of application to a coating film and can impart physical properties excellent in weather resistance, water resistance, stain resistance, stickiness, and gloss retention. This has the effect that it becomes possible.

Claims (4)

(57) [Claims] An emulsion polymerization of a monomer component (A) containing a polymerizable monomer (a) having reactivity with an acidic group and a polymerizable monomer (b) having an acidic group, The monomer component (B) is preliminarily emulsified in water with an emulsifier in a state where at least a part of the group is neutralized.
A method for producing an aqueous resin dispersion which is subjected to emulsion polymerization by a pre-emulsion method to be introduced into a reaction system, wherein the total amount of the monomer component (A) and the monomer component (B) is
Then , a polymerizable monomer (c) having a cycloalkyl group in an amount within the range of 10% by weight to 80% by weight is added to at least one of the monomer component (A) and the monomer component (B). A method for producing an aqueous resin dispersion. 2. A monomer component (A) containing a polymerizable monomer (a) having reactivity with a nitrogen-containing functional group and / or an acidic group, and a polymerizable monomer (b) having an acidic group. Is emulsion-polymerized, and in a state where at least a part of the acidic group is neutralized, a monomer component (B) containing a polymerizable monomer (d) having a nitrogen-containing functional group is previously added to water with an emulsifier. Reaction system in emulsified state
A method for producing an aqueous resin dispersion emulsion-polymerized by a pre-emulsion method, wherein the total amount of the monomer component (A) and the monomer component (B) is
Then , a polymerizable monomer (c) having a cycloalkyl group in an amount within the range of 10% by weight to 80% by weight is added to at least one of the monomer component (A) and the monomer component (B). A method for producing an aqueous resin dispersion. 3. The aqueous resin dispersion according to claim 1, wherein the monomer component (B) further contains a polymerizable monomer (a) reactive with the acidic group. Production method. 4. A polymerizable monomer (c) having a cycloalkyl group is represented by the general formula (1): ## STR1 ## (Wherein, R ₁ represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and Z represents a cycloalkyl group including those having a substituent).
4. The method for producing an aqueous resin dispersion according to 2 or 3.