JP5484999B2 - Paint composition - Google Patents

Description

  The present invention relates to a coating composition. In particular, the present invention relates to an antistatic coating composition containing a (meth) acrylic polymer.

  One of the performance evaluations required for paints is the aesthetic design and appearance of the paint film. However, with the conventional technology, when it is applied during low temperature drying (winter season) or during high temperature and high humidity (rainy season to summer season), the paint film is squeezed (a phenomenon in which the paint film surface has a crepe pattern). There was a drawback that it was difficult to obtain the appearance of the coating film. In the case of a coating composition comprising a polymer emulsion, if the polymerization stability of the polymer emulsion is poor at the time of polymer synthesis, the monomer that remains unreacted causes defects such as unevenness, mottle, and see-through in the coating film, and is uniform. In such a case, it is difficult to apply a coating with a sufficient film thickness. In such cases, generally the coating film performance, gloss, smoothness of the coating film, adhesion to the object, chemical resistance or weather resistance, etc. It was extremely bad. From the above viewpoints, it has been difficult to say that conventional techniques pay close attention to defects related to coating film appearance.

  As one of the means for improving the above drawbacks, a (meth) acrylic polymer composition which is generally excellent in polymerization stability and also has low odor, low bubble property and antistatic property is used as a coating composition. ing. However, if the above-described drawbacks are still insufficiently improved, a technique for imparting an antistatic function to the (meth) acrylic polymer composition paint is taken. As a method of imparting an antistatic function, a method of applying an antistatic agent made of a surfactant to the surface of an article (for example, Patent Document 1) or a method of using a composition mixed with carbon black (for example, Patent Document) 2) has been proposed.

JP-A-8-13350 JP 2005-186550 A

  However, the antistatic effect of the composition using the antistatic agent described in Patent Document 1 is temporary and decreases early. Moreover, the composition in which carbon black described in Patent Document 2 is mixed has a problem that the work process is complicated and the surface of the article becomes dirty.

  In addition, kneading and coating of an antistatic agent into a surfactant have problems such as a decrease in transparency and coloring. At that time, there is a concern that a decrease in film physical properties due to kneading causes problems such as insufficient ink adhesion on the surface and an increase in cost.

  Therefore, the objective of this invention is providing the composition for coating materials used in order to provide the articles | goods provided with the more preferable antistatic film | membrane by providing the more superior antistatic technique.

  As a result of intensive studies to solve the above problems, the present inventors have found a polymer composition using, as a reactive monomer, a methacrylic acid ester containing a (poly) oxyalkylene chain in the molecule. The present invention was completed by finding that the coating composition containing the coating composition had excellent anti-static effects after coating.

  That is, the present invention is a coating composition containing a polymer having a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain in the molecule.

  According to the present invention, a coating film having an excellent antistatic effect by using a coating composition containing a polymer having a structural unit derived from an unsaturated carboxylic acid ester containing a (poly) oxyalkylene chain in the molecule. Is obtained.

  The present invention provides a coating composition comprising a polymer having a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain in the molecule.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, this invention is not restrict | limited to the following preferable embodiment.

The polymer used in the coating composition of the present invention is not particularly limited as long as it contains a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain in the molecule, but at least the following formula ( The polymer is preferably a polymer containing a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain ((OA) _n ) represented by 1).

In the above formula (1), R ₁ represents a C2 to C8 alkyl group, a C3 to C8 cycloalkyl group, or a C6 to C13 aryl group. Here, the C2 to C8 alkyl group is a linear or branched alkyl group having 2 to 8 carbon atoms. Specifically, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n -Linear or branched alkyl groups, such as -octyl group or 2-ethylhexyl group. Of these, n-butyl group and 2-ethylhexyl group are more preferable. Examples of the C3-C8 cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a 2-methylcyclopropyl group, a cyclopentyl group, a 2- or 3-methylcyclobutyl group, a cyclohexyl group, a cycloheptyl group, or a cyclooctyl group, And cycloalkyl groups such as Furthermore, examples of the C6-C13 aryl group include phenyl group, o-, m- or p-tolyl group, 2,3- or 2,4-xylyl group, mesityl group, naphthyl group and biphenylyl group. . Of these, a phenyl group and a naphthyl group are more preferable. Of these, an n-butyl group is particularly preferred.

If R ₁ is a group as described above, emulsion polymerization proceeds efficiently, the formation of deposits and aggregates adhering to the inside of the reactor is suppressed and prevented, and the polymerization stability of the resulting polymer emulsion and Mechanical stability can be maintained. In such a case, a polymer emulsion having a small particle diameter can be produced, and the water resistance, fastness and transparency can be improved.

Further, in the above formula (1), R ₂ is a hydrogen atom or a methyl group. n represents the average number of oxyalkylene groups present in the formula (1), and is a number of 1 to 3. When n exceeds 3, it is not preferable because the amount of aggregates produced during emulsion polymerization increases and the polymerization stability and mechanical stability of the produced polymer emulsion may decrease.

  OA is an oxyethylene group, an oxypropylene group, or an oxybutylene group (that is, A is an ethylene group, a trimethylene group, a 2-methyltrimethylene group, or a tetramethylene group, a sec-butylene group, or a tert-butylene group. Is). Preferably, OA is an oxyethylene group or an oxypropylene group, more preferably an oxyethylene group. With such an oxyalkylene group, production costs are reduced, moderate hydrophilicity is imparted, emulsion polymerization proceeds efficiently, and the formation of deposits and aggregates adhering to the inside of the reactor is suppressed / prevented, Furthermore, the polymerization stability and mechanical stability of the resulting polymer emulsion can be maintained. Further, since the dispersibility, hydrophobicity, etc. of the monomer can be controlled by changing the average addition mole number n of OA, it is more preferable to appropriately determine the range of n according to desired characteristics and intended use. . In the formula (1), when there are a plurality of OA, that is, when n in the formula (1) is 2 or more, the oxyalkylene group defined by OA is composed of only one type. In addition, it may be composed of two or more types. When the oxyalkylene group is composed of two or more types, two or more types of oxyalkylene groups may be randomly arranged, and each may be arranged in blocks.

  The production method of the unsaturated carboxylic acid ester having the (poly) oxyalkylene chain is not particularly limited, but a general known ester synthesis method can be used. For example, a transesterification reaction between an unsaturated carboxylic acid ester and an alcohol, a condensation reaction between an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride, and an alcohol. The above alcohol is glycol ether or glycol. When glycol is used, it can be used for ester synthesis after synthesizing glycol ether, or the terminal hydroxyl group is protected by general ether synthesis reaction after ester synthesis. Can also be used.

  The polymer which concerns on this invention should just contain the structural unit derived from the unsaturated carboxylic acid ester of the said Formula (1) at least. Therefore, the polymer according to the present invention is copolymerizable with the homopolymer of the unsaturated carboxylic acid ester of the above formula (1), or the unsaturated carboxylic acid ester of the above formula (1) and the unsaturated carboxylic acid ester. Copolymers with other monomers may also be used.

  Here, the polymer according to the present invention is an unsaturated carboxylic acid ester of the above formula (1) and other monomers copolymerizable with the unsaturated carboxylic acid ester (in the present specification, simply referred to as “other monomers”). The other monomers that can be used in the case of a copolymer with (also referred to as "body") are not particularly limited, but (meth) acrylic acid, itaconic acid, citraconic acid, crotonic acid, maleic acid, maleic anhydride , Carboxylic acids such as fumaric acid and salts of the above carboxylic acids such as sodium, potassium and ammonium salts thereof; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, (meth ) Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohex (meth) acrylate , Ethylhexyl acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, n-lauryl (meth) acrylate, n-stearyl (meth) acrylate, oxalic acid mono Hydroxyethyl (meth) acrylate, tetrahydroxyphthalic acid monohydroxyethyl (meth) acrylate, tetrahydrophthalic acid monohydroxypropyl (meth) acrylate, 5-methyl-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth) acrylate, phthalic acid Monohydroxyethyl (meth) acrylate, monohydroxypropyl phthalate (meth) acrylate, monohydroxyethyl (meth) acrylate maleate, monohydroxypropyl maleate ( ) Acrylate, tetrahydroxyphthalate monohydroxybutyl (meth) acrylate, 2-hydroxy-n-propyl (meth) acrylate, 4-hydroxy-n-butyl (meth) acrylate, diacetone (meth) acrylate, acetonyl (meth) ) Acrylates, 2-hydroxy-n-propyl (meth) acrylate acetyl acetate, acetoacetoxyethyl (meth) acrylate, butanediol-1,4- (meth) acrylate, glycidyl (meth) acrylate and other (meth) acrylic Acid alkyl ester; aromatic vinyl such as styrene, α-methylstyrene, chlorostyrene, dimethylaminostyrene, nitrostyrene, divinylbenzene, vinyltoluene, o-methylstyrene, p-methoxystyrene, vinylnaphthalene , Ethylene, propylene, 1-butene, olefins such as 1-octene; acrylamide, (meta) acrylonitrile, and diethyl fumarate. Of these, (meth) acrylic acid and salts thereof, (meth) acrylic acid alkyl ester, and aromatic vinyl are preferable, and (meth) acrylic acid and aromatic vinyl are more preferable. Specifically, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isopropyl (meth) acrylate, ethylhexyl acrylate, (meth) acrylic acid 2- Ethylhexyl, styrene, and p-methoxystyrene are more preferable, and (meth) acrylic acid and styrene are particularly preferable. The other monomers may be used alone or in the form of a mixture of two or more. In the present application, “(meth) acrylic acid” refers to acrylic acid or methacrylic acid, and “(meth) acrylate” refers to acrylate or methacrylate.

  Therefore, the polymer according to the present invention includes a homopolymer of the unsaturated carboxylic acid ester of the above formula (1) or a structural unit derived from the unsaturated carboxylic acid ester of the above formula (1) and (meth) acrylic acid and The copolymer is preferably a copolymer having a structural unit derived from at least one monomer selected from the group consisting of a salt thereof, an alkyl (meth) acrylate, and an aromatic vinyl. A structural unit derived from at least one monomer selected from the group consisting of a homopolymer of a carboxylic acid ester, or a structural unit derived from an unsaturated carboxylic acid ester of formula (1) and (meth) acrylic acid and aromatic vinyl More preferably, it is a copolymer having

  The composition of the polymer in the case where the polymer according to the present invention is a copolymer of the unsaturated carboxylic acid ester of the above formula (1) and another monomer is not particularly limited. It is preferable that excellent performance can be exhibited. Specifically, the content of the unsaturated carboxylic acid ester of the above formula (1) is preferably 40 to 99 parts by mass, and 40 to 60 parts by mass with respect to 100 parts by mass of the total mass of the monomers. More preferably, it is contained.

  The polymerization method of the unsaturated carboxylic acid ester and, if necessary, other monomers is not particularly limited, but an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, an interfacial polymerization method and the like can be used. For example, when an acrylate ester is polymerized, according to a general emulsion polymerization method, an acrylic resin is produced by (co) polymerizing the acrylate ester or other monomer in the presence of an emulsifier. It may be. A typical emulsion polymerization method is, for example, a method in which the above components are pre-emulsified in water and added dropwise together with a polymerization initiator under heating and stirring.

  The emulsifier is a cationic emulsifier, an anionic emulsifier, a nonionic emulsifier, or an amphoteric emulsifier. In addition to those generally used for emulsion polymerization, surfactants can also be used. The cationic emulsifier is, for example, an alkyl ammonium salt such as dodecyl ammonium chloride or a quaternary ammonium salt. The anionic emulsifier is, for example, diammonium dodecyl diphenyl ether disulfonate, sodium dodecyl diphenyl ether disulfonate, dodecyl diphenyl ether disulfonic acid. Alkyl diphenyl ether disulfonates such as calcium and sodium alkyl diphenyl ether disulfonate; alkyl benzene sulfonates such as sodium dodecylbenzene sulfonate and ammonium dodecylbenzene sulfonate; alkyl sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; fatty acid sodium and olein Aliphatic carboxylates such as potassium acid; Polio Sulylene ester-containing sulfate ester salts (for example, polyoxyethylene alkyl ether sulfate salts such as sodium polyoxyethylene alkyl ether sulfate and ammonium polyoxyethylene alkyl ether sulfate; sodium polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl phenyl ether) Polyoxyethylene alkyl phenyl ether sulfates such as ammonium sulfate; polyoxyethylene polycyclic phenyl ether sodium sulfate, polyoxyethylene polycyclic phenyl ether sulfates such as ammonium polyoxyethylene phenyl ether sulfate), etc .; formalin naphthalene sulfonate Naphthalene sulfonic acid formalin condensate salt such as sodium condensate; Alkylsulfosuccinates such as sodium succinate and disodium monoalkylsulfosuccinate, polyoxyethylene-polyoxypropylene glycol ether sulfate, sulfonate or sulfate ester groups and polymerizable carbon-carbon (unsaturated) double bonds In the molecule, the nonionic emulsifier includes, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene tridecyl ether, polyoxyethylene oleyl ether, and the like. Polyoxyalkylene alkyl phenyl ether compounds, polyoxyalkylene alkyl phenyl ether compounds such as polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene Polyoxyalkylene unit-containing ether compounds such as polyoxyalkylene polycyclic phenyl ether compounds such as tylene polycyclic phenyl ether; polyoxyalkylenes such as polyoxyethylene monolaurate, polyoxyethylene monostearate, and polyoxyethylene monooleate Alkyl ester compounds; polyoxyalkylene alkylamine compounds such as polyoxyethylene alkylamine; sorbitan compounds such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate The amphoteric emulsifier is lauryl betaine, lauryl dimethylamine oxide or the like. These may be used alone or in combination of two or more appropriately selected. The addition amount of the emulsifier is not particularly limited, but is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 15 parts by mass, and particularly preferably 2 to 100 parts by mass of the total mass of the monomers. 8 parts by mass. In the presence of such an amount of emulsifier, the entire polymer composition can be sufficiently emulsified.

  The polymerization initiator used at the time of emulsion polymerization is one that causes radical polymerization by heat or a reducing substance to cause addition polymerization of a radically polymerizable unsaturated monomer. An oxide, an azobis compound, etc. can be used. Examples include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, benzoyl peroxide, o-methoxybenzoyl peroxide, o-chloro. Organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis -2,4-dimethylvaleronitrile, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-diaminopropane) hydrochloride, 2,2'-azobis (2-methylbutyrate) Nitrile), 2,2'-azo (2,4-dimethylvaleronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] 2,2′-azobis [2- (2-imidazolin-2-yl) propane], azo compounds such as dimethyl methylpropane isobutyrate, and the like. In addition, inorganic peroxides such as hydrogen peroxide, sodium persulfate, potassium persulfate, and ammonium persulfate. The organic or inorganic peroxide may be combined with a reducing agent to form a redox polymerization initiator. Examples of the reducing agent include L-ascorbic acid, L-sorbic acid, sodium metabisulfite, ferrous sulfate, Rongalite and the like. These may be used alone or in combination of two or more appropriately selected, and ammonium persulfate is preferably used. The addition amount of a polymerization initiator is not specifically limited, It can adjust suitably according to the desired molecular weight of the target emulsion polymer. The addition amount of the polymerization initiator is preferably 0.1 to 17 parts by mass, more preferably 0.7 to 10.5 parts by mass, and particularly preferably 4.5 to 100 parts by mass of the total mass of the monomers. -5.5 parts by mass. In the presence of such an amount of the polymerization initiator, the entire polymer composition can be sufficiently polymerized.

  A chain transfer agent can also be added to adjust the molecular weight of the polymer. Examples of the chain transfer agent include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, and γ-mercapto. Examples include mercaptan compounds such as propylmethyldiethoxysilane, organic halides such as chloroform and carbon tetrachloride, sulfide benzene, isopropylbenzene, and ferric chloride.

  The reaction temperature of the emulsion polymerization is not particularly limited as long as radical polymerization can occur, but is preferably 100 ° C. or lower, more preferably 70 to 90 ° C., and particularly preferably 75 to 85 ° C. By emulsion polymerization as described above, a polymer emulsion containing an emulsion polymer obtained by sufficiently emulsion polymerization of the unsaturated carboxylic acid ester having the (poly) oxyalkylene chain is obtained.

  The molecular weight of the emulsion polymer thus obtained is not particularly limited as long as it is a polymer containing a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain in the molecule. Preferably, the polymer (emulsion polymer) according to the present invention has a mass average molecular weight of 1,000 to 1,000,000, more preferably 10,000 to 100,000. A polymer having such a molecular weight can provide sufficient antistatic properties. Moreover, since the stability of the emulsion is maintained, the polymerization stability is excellent, the formation of aggregates after polymerization can be suppressed / prevented, and the resulting polymer emulsion exhibits sufficient fluidity. For this reason, the paint comprising the polymer according to the present invention can exhibit an excellent antistatic effect, anti-condensation effect, anti-contamination effect, etc. without using an antistatic agent, and has excellent transparency. In addition, the ink adhesion on the surface and the surface can be formed, and a smooth coating film without unevenness can be formed with little deterioration in performance such as coloring. The “mass average molecular weight” in the present specification is a value measured in terms of polyethylene glycol by the gel permeation chromatography (hereinafter abbreviated as “GPC”) method under the following measurement conditions.

<Measurement conditions of molecular weight by GPC>
Column used: HZ2000, manufactured by Tosoh Corporation
Eluent: THF
Driving amount: 5 μL
Eluent flow rate: 0.35 mL / min
Column temperature: 40 ° C
Standard substance: polyethylene glycol, peak top molecular weight (Mp) 68185
Calibration curve order: linear equation Detector: manufactured by Tosoh Corporation, HLC-8220GPC
Analysis software: Multi-station GPC-8020 manufactured by Tosoh Corporation
Further, the emulsion polymer obtained in this way may be obtained in any shape such as particulate, particulate, powder, amorphous, columnar, angular, etc., but the particulate, particulate, powder The shape is preferable, and the particle shape and the fine particle shape are more preferable. Further, the size of the emulsion polymer is not particularly limited. For example, when the emulsion polymer is in the form of particles or particles, the mass average particle diameter is preferably 0.05 to 1 μm, more preferably 0.05 to 0.5 μm, and particularly preferably. 0.1 to 0.25 μm. The “mass average particle diameter” in the present specification is a value obtained by measuring a sample obtained by diluting a polymer emulsion with a laser diffraction particle size analyzer, and more specifically, measured in the following examples. Value.

  The viscosity of the aqueous emulsion containing the polymer (emulsion polymer) according to the present invention is not particularly limited, but is preferably a viscosity having the molecular weight as described above. Specifically, the viscosity of the aqueous emulsion is preferably 1000 mPa · s or less, more preferably at 25 ° C., 60 rpm, and 6 rpm measured by a Brookfield (B-type) rotational viscometer. 10 to 200 mPa · s. In addition, the “viscosity of the aqueous emulsion” in the present specification is a value measured more specifically in the following examples.

  The (poly) oxyalkylene chain in the structural unit of the polymer adsorbs moisture in the air due to its hydrophilicity and prevents the object from being charged. Therefore, according to the present invention, by using a hydrophilic (poly) oxyalkylene chain in the structural unit of the polymer in the coating material, the coating material has excellent antistatic properties without using an antistatic agent separately. Demonstrate the effect. In addition, since it does not require the kneading of the antistatic agent, the coating film formed with the coating material containing the polymer has a smooth surface without unevenness, exhibits excellent transparency and surface ink adhesion, and is colored. It is possible to suppress / prevent performance degradation. Further, when the above-described polymer is obtained by emulsion polymerization, the stability of the emulsion can be maintained, so that the polymerization stability is excellent, the formation of aggregates after the polymerization can be suppressed / prevented, and the obtained weight can be reduced. The combined emulsion exhibits sufficient fluidity. For this reason, the coating film formed using the coating composition containing the polymer exhibits excellent gloss and smoothness, and can improve defects in the coating film appearance such as blemishes and unevenness. In addition, this invention is not restrict | limited by the said mechanism.

  The coating composition of the present invention can be blended with the above-described polymer, preferably in the form of an emulsion polymer (emulsion). Here, the solid content concentration of the polymer in the emulsion is not particularly limited, but is preferably 20 to 80 parts by mass, more preferably 40 to 60 parts by mass with respect to 100 parts by mass of the emulsion.

  In addition to the above polymer, the coating composition of the present invention may contain an appropriate amount of an additive in a range that does not affect the effects of the present invention. Although the additive which can be used in this case is not particularly limited, it can be appropriately selected according to a desired application. Specifically, pigments commonly used in paints (titanium dioxide, calcium carbonate, barium sulfate, white carbon, carbon, petal, ocher, cyanine blue, etc.), film forming aids, colloidal silica, plasticizers, solvents, dispersions Agents, wetting agents, preservatives, antifreezing agents, light stabilizers, ultraviolet absorbers, antifoaming agents and the like.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

Synthesis example 1
In a 500 ml flask equipped with a stirrer and a raw material inlet, 86.53 g of ion-exchanged water and 13.33 g of New Coal 707-SF (manufactured by Nippon Emulsifier Co., Ltd.) as an emulsifier (surfactant) are mixed and stirred at 500 rpm / min. While maintaining at 10-25 ° C. In addition, the said Newcol 707-SF (made by Nippon Emulsifier Co., Ltd.) is a polyoxyethylene polycyclic phenyl ether sulfate NH ₄ salt represented by the following formula, and is referred to as N-707SF in Tables 1 to 3 below.

  In the formula, R is a polycyclic phenyl group.

In the aqueous solution, triethylene glycol mono-n-butyl ether adduct adduct [CH ₂ ═C (CH ₃ ) COO (CH ₂ CH ₂ O) ₃ —n—C ₄ H ₉ ; BTG-MA] as a monomer 200.0 g was charged in 5 portions, and a 10% by mass ammonium persulfate (APS) aqueous solution was added as a polymerization initiator so that the APS was 5 parts by mass with respect to 100 parts by mass of the total mass of the monomers. Thereafter, the mixture was stirred for 30 minutes to obtain an emulsion dropping liquid.

  Next, in a 500 ml separable flask equipped with a stirrer, a reflux cooler, and a raw material charging port, 100 g of ion-exchanged water and 1% by mass, 5% by mass, or 10% by mass of the emulsion dropping liquid were added in a nitrogen atmosphere. Each was charged, heated to 80 ° C., and initial polymerization was performed for 30 minutes. In addition, in the following Tables 1-3, the addition amount of the emulsion dropping liquid in the initial polymerization is described as “Seed addition amount”.

  Thereafter, the remaining emulsion dropping solution was added dropwise over 3 hours, and after completion of the addition, the mixture was further aged at 80 ° C. for 1 hour. The obtained polymer emulsions (1) to (3) were cooled to 30 ° C. or lower and filtered through a 100 mesh screen to collect aggregates in the emulsion. In addition, agglomerates adhering to the flask and the stirring blade were also collected.

  The mass average particle diameters of the polymer emulsions (1) to (3) were 0.190 μm, 0.152 μm, and 0.135 μm, respectively.

Synthesis example 2
BTG-MA, methyl methacrylate and acrylic acid were mixed at a mass ratio of 90: 9: 1 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used instead of BTG-MA, and the same as Synthesis Example 1 except that 1% by mass or 5% by mass of the emulsion dropping liquid was charged. Thus, polymer emulsions (4) and (5) were obtained.

  The mass average particle diameters of the polymer emulsions (4) and (5) were 0.241 μm and 0.148 μm, respectively.

Synthesis example 3
BTG-MA, methyl methacrylate and acrylic acid were mixed at a mass ratio of 90: 9: 1 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used instead of BTG-MA, and New Coal 2320-SN (manufactured by Nippon Emulsifier Co., Ltd.) was used as an emulsifier (surfactant). A polymer emulsion (6) was obtained in the same manner as in Synthesis Example 1 except that 1% by mass of the product dropping liquid was charged. In addition, the said Newcol 2320-SN (made by Nippon Emulsifier Co., Ltd.) is a polyoxyalkylene alkyl ether sulfate Na salt represented by the following formula, and is referred to as N-2320SN in the following Tables 1 to 3.

  In the formula, R is a group derived from a C12C13 synthetic alcohol (meaning a mixed alcohol of a C12 synthetic alcohol and a C13 synthetic alcohol).

  The mass average particle diameter of this polymer emulsion (6) was 0.204 μm.

Synthesis example 4
BTG-MA, methyl methacrylate, styrene and acrylic acid were mixed at a mass ratio of 49: 34: 15: 2 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used instead of BTG-MA, and the same as Synthesis Example 1 except that 1% by mass or 5% by mass of the emulsion dropping liquid was charged. Thus, polymer emulsions (7) and (8) were obtained.

  The mass average particle diameters of the polymer emulsions (7) and (8) were 0.187 μm and 0.150 μm, respectively.

Comparative Synthesis Example 1
In Synthesis Example 1, 200.0 g of n-butyl methacrylate (n-BMA) was used in place of BTG-MA, and 1% by mass of the emulsion dropping solution was charged. Thus, a comparative polymer emulsion (1 ′) was obtained.

  The weight average particle diameter of this comparative polymer emulsion (1 ′) was 0.224 μm.

Comparative Synthesis Example 2
n-BMA, methyl methacrylate and acrylic acid were mixed at a mass ratio of 90: 9: 1 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used in place of BTG-MA, and 1 wt% of the emulsion dropping solution was charged. A combined emulsion (2 ′) was obtained.

  The comparative polymer emulsion (2 ′) had a mass average particle diameter of 0.262 μm.

Comparative Synthesis Example 3
Ethylhexyl acrylate (2-EHA), methyl methacrylate and acrylic acid were mixed at a mass ratio of 90: 9: 1 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used instead of BTG-MA, and New Coal 2320-SN (manufactured by Nippon Emulsifier Co., Ltd.) was used as an emulsifier (surfactant). A comparative polymer emulsion (3 ′) was obtained in the same manner as in Synthesis Example 1 except that 1% by mass of the product dropping liquid was charged.

  The comparative polymer emulsion (3 ′) had a mass average particle diameter of 0.190 μm.

Comparative Synthesis Example 4
n-BMA, methyl methacrylate, styrene and acrylic acid were mixed at a mass ratio of 49: 34: 15: 2 to prepare a monomer mixture.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used in place of BTG-MA, and 1 wt% of the emulsion dropping solution was charged. A combined emulsion (4 ′) was obtained.

  The comparative polymer emulsion (4 ′) had a mass average particle diameter of 0.237 μm.

Comparative Synthesis Example 5
A monomer mixture was prepared by mixing n-butyl acrylate (n-BA), methyl methacrylate, styrene and acrylic acid in a mass ratio of 49: 34: 15: 2.

  In Synthesis Example 1, 200.0 g of this monomer mixture was used in place of BTG-MA, and 1 wt% of the emulsion dropping solution was charged. A combined emulsion (5 ′) was obtained.

  The comparative polymer emulsion (5 ′) had a mass average particle diameter of 0.209 μm.

Examples 1-8 and Comparative Examples 1-5
For the polymer emulsions (1) to (8) obtained in Synthesis Examples 1 to 3 and the comparative polymer emulsions (1 ′) to (5 ′) obtained in Comparative Synthesis Examples 1 to 5, according to the following method: The performance was evaluated, and the results are shown in Tables 1 to 3 below. In Tables 1 to 3 below, “-” represents that no measurement was performed.

<Performance evaluation method>
(1) Polymerization stability The collected aggregates were dried and weighed at 110 ° C. for 2 hours to determine the aggregate amount. The ratio (%) of the mass of the aggregate to the total mass (solid content) of the polymer used was expressed as polymerization stability (%).

In addition, it shows that it is excellent in polymerization stability, so that this value is small.
(2) Average particle diameter of polymer emulsion particles The obtained polymer emulsion was neutralized with 25% aqueous ammonia to a pH of 6.5 to 8.0. The average particle diameter was measured (unit: μm) using a light scattering diffraction type particle size distribution analyzer LS230 manufactured by Beckman Coulter.
(3) Viscosity The viscosity before and after neutralization of the polymer emulsion at 25 ° C. was measured with a B-type rotational viscometer (rotor No. 2) at 60 rpm and 6 rpm (unit: mPa · s).
(4) Polymerization conversion rate It calculates from the non volatile matter (solid content) of the obtained polymer emulsion.

(5) Glossiness test A polymer emulsion having a thickness of 3 mm was formed on a glass plate and dried at 110 ° C. for 30 seconds. The glossiness at 20 ° and 60 ° of the film was measured by 1G-331 manufactured by Horiba. In the following table, samples with a glossiness of 50 or more are indicated with “◯”, and samples with less than 50 are indicated with “x”.
(6) Surface resistivity The polymer emulsion was formed on a glass plate to a thickness of 3 mm and dried at 110 ° C. for 30 seconds. The surface resistivity was measured using a surface resistivity meter.

  From the results of Tables 1 to 3, the polymer emulsions (1) to (6) of the present invention have a surface characteristic that is up to two orders of magnitude larger than the comparative polymer emulsions (1 ′) to (5 ′) of the comparative examples. It shows a resistance value and is found to be excellent in antistatic properties. In addition, the polymer emulsions (7) and (8) of the present invention showed an excellent effect in gloss as compared with the comparative polymer emulsion (4 '). Furthermore, the obtained coating film was excellent in water resistance, antifouling property, abrasion resistance, low odor property, and low bubble property.

  The present invention does not require an additional step of adding an antistatic agent, is suitably used for coating an object to be charged and requires glossiness, and is suitable as a paint for a portion that is more likely to deteriorate.

Claims (4)

A coating composition comprising a polymer having a structural unit derived from an unsaturated carboxylic acid ester having a (poly) oxyalkylene chain in the molecule, and an emulsifier ,
The polymer has the formula (1):
In the formula, R ₁ is a C2-C8 alkyl group, a C3-C8 cycloalkyl group or a C6-C13 aryl group, R ₂ is a hydrogen atom or a methyl group, and n is 1 to 3. OA is an oxyethylene group, an oxypropylene group, or an oxybutylene group; derived from a homopolymer of an unsaturated carboxylic acid ester represented by the formula (1) or an unsaturated carboxylic acid ester of the formula (1) It is a copolymer comprising a structural unit and a structural unit derived from at least one monomer selected from the group consisting of (meth) acrylic acid and salts thereof, (meth) acrylic acid alkyl ester, aromatic vinyl,
The emulsifier is polyoxyalkylene alkyl ether sulfate or polyoxyalkylene polycyclic phenyl ether sulfate,
Content of the said emulsifier is a composition for coating materials which is 0.1-30 mass parts with respect to 100 mass parts of monomers which comprise the said polymer . The group polymer, consisting of the formula (1) of structural units and (meth) acrylic acids and aromatic vinyl derived from an unsaturated carboxylic acid ester of a homopolymer of an unsaturated carboxylic acid ester or formula (1) it is at least one consisting of structural units derived from monomers of the copolymer is more selective, coating composition of claim 1. The copolymer contains 40 to 99 parts by mass of a structural unit derived from the unsaturated carboxylic acid ester of the formula (1) with respect to 100 parts by mass of the structural unit derived from the monomer constituting the copolymer. The coating composition according to claim 1 or 2. In the presence of the emulsifier, the coating composition comprises the unsaturated carboxylic acid ester of the formula (1), or the unsaturated carboxylic acid ester of the formula (1) and (meth) acrylic acid and a salt thereof, (meth) The coating composition according to any one of claims 1 to 3, which is produced by polymerizing at least one monomer selected from the group consisting of alkyl acrylates and aromatic vinyls.