JP2016040361A - Manufacturing method of polymer dispersion liquid, coating material and coated article obtained from polymer dispersion liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polymer dispersion liquid excellent in low temperature storage stability.SOLUTION: There is provided a manufacturing method of a polymer dispersion liquid including a process (1) of polymerizing an urethane resin (A) and one or more kinds of radical polymerizable monomer mixtures X to obtain a dispersion liquid containing a polymer P and a process (2) of polymerizing by adding one or more kinds of radical polymerizable monomer mixtures Y to the dispersion liquid containing the polymer P to obtain a dispersion liquid containing a polymer Z, where Tg (X) and SP (X), where Tg (X) [unit: °C] is a glass transition temperature calculated from the FOX formula and SP(X) [unit: (J/cm)] is a solubility parameter (SP value) by a Fedors method of the polymer obtained by polymerizing the radical polymerizable monomer mixture X, satisfy formula (1). The formula (1) is SP(X)≥-0.0125Tg(X)+19.875, where -60≤Tg(X)≤170.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polymer dispersion, a coating material obtained from the polymer dispersion, and a coated product.

Conventionally, in the paint field, conversion from organic solvent-based paints to water-based paints has been attempted from the viewpoint of environmental protection and safety and health. However, water-based paints have lower coating film appearance, weather resistance, water resistance, solvent resistance, and contamination resistance than organic solvent-based paints, and there are many problems to be solved.
In order to solve these various problems, a coating material containing an in-particle mixture of resins having different properties has been proposed.
For example, Patent Documents 1 and 2 disclose a polymer in which an acrylic monomer is emulsion-polymerized in an aqueous dispersion of a urethane polymer to form a particulate mixture of the urethane polymer and the acrylic polymer. Is described.

JP 2000-281705 A JP 2005-120304 A

  The polymer dispersion of the polymer in which the urethane polymer and the acrylic polymer described in Patent Document 1 and Patent Document 2 are mixed to form particles has a problem that the low-temperature storage stability is insufficient. .

The present invention has the following configuration.
[1] Step (1) of polymerizing the urethane resin (A) and one or more radical polymerizable monomer mixture X to obtain a dispersion containing the polymer P, and a dispersion containing the polymer P (1) including a step (2) of adding one or more radical polymerizable monomer mixture Y to perform polymerization to obtain a dispersion containing polymer Z,
The glass transition temperature of the polymer obtained by polymerizing the radical polymerizable monomer mixture X is Tg (X) [unit: ° C.] determined by the FOX equation, and the solubility parameter (SP value) by the Fedors method is used. A method for producing a polymer dispersion, in which, when SP (X) [unit: (J / cm ³ ) ^1/2 ], the Tg (X) and SP (X) satisfy the following formula (1).
SP (X) ≧ −0.0125Tg (X) +19.875 (1)
However, −60 ≦ Tg (X) ≦ 170.
[2] The radical polymerizable monomer mixture X includes a monomer (x1) having two or more radical polymerizable groups and a radical polymerizable monomer (x2) other than the monomer (x1). The method for producing a polymer dispersion liquid according to [1], which is a mixture containing
[3] A polymer dispersion obtained by the production method according to [1] to [2].
[4] A coating material containing the polymer dispersion according to [3].
[5] A coated product to which the coating material according to [4] is applied.

  The polymer dispersion obtained by the production method of the present invention is excellent in low-temperature storage stability. In particular, when the coating film obtained from the polymer dispersion obtained by the production method of the present invention has crystallinity, it is excellent in low-temperature storage stability, which is a problem caused by having crystallinity.

It is the graph which plotted Tg (X) and SP (X) of the radically polymerizable monomer mixture X used in each example of an Example.

  Hereinafter, a method for producing a polymer dispersion, a coating material using the polymer dispersion, and a coated product will be sequentially described in detail.

<Method for producing polymer dispersion>
A step (1) of polymerizing the urethane resin (A) and one or more kinds of radical polymerizable monomer mixture X (hereinafter sometimes simply referred to as the mixture X) to obtain a dispersion containing the polymer P; And a step (2) of adding a one or more radical polymerizable monomer mixture Y to the dispersion containing the polymer P to perform polymerization to obtain a dispersion containing the polymer Z. .
The polymer Z obtained by the production method of the present invention contains a polymer P, and the polymer P contains a urethane resin (A).
In the present specification, the “radical polymerizable monomer mixture” means containing one or more of the above-mentioned radical polymerizable monomers. That is, the radical polymerizable monomer mixture includes those containing only one kind of radical polymerizable monomer.

[Urethane resin (A)]
In the present invention, the urethane resin (A) refers to a resin obtained by reacting a diol with a polyvalent isocyanate compound.
A diol is an organic compound having two hydroxy groups in one molecule. Specific examples include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, Relatively low molecular weight diols such as neopentyl glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, hexanediol, cyclohexanedimethanol; and at least one of these diols Polyester diols obtained by polycondensation with at least one dicarboxylic acid such as adipic acid, sebacic acid, itaconic acid, maleic anhydride, terephthalic acid, isophthalic acid; polyethylene glycol, poly B propylene glycol, polycaprolactone diol, polytetramethylene ether diol, polyether diols and polycarbonate diols; polybutadiene diol, hydrogenated polybutadiene diol, polyacrylate diol. In the production of the urethane resin (A), these diols may be used alone or in combination of two or more.

  The polyvalent isocyanate compound means an organic compound having at least two isocyanate groups in one molecule, and examples thereof include aliphatic, alicyclic and aromatic polyvalent isocyanate compounds. Specific examples of the polyvalent isocyanate compound include dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-tolylene diisocyanate, 2, , 6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, and the like. In the production of the urethane resin (A), these polyvalent isocyanate compounds may be used alone or in combination of two or more. Among these, aliphatic or alicyclic isocyanates are preferable because the resulting urethane resin (A) has little yellowing.

Examples of the method for producing the urethane resin (A) include a method of reacting the above-mentioned diol with isocyanate in a ether such as dioxane using a catalyst such as dibutyltin dilaurate.
The weight average molecular weight of the urethane resin (A) obtained by such a method is preferably 500 or more, more preferably 1000 or more, from the viewpoint of improving the reactivity of the radical polymerizable monomer. . As an upper limit, it is preferable that it is 500,000 or less, and it is more preferable that it is 400,000 or less. That is, the weight average molecular weight of the urethane resin (A) is preferably 500 to 500,000, and more preferably 1000 to 400,000. Here, the “weight average molecular weight” means a value calculated by gel conversion using gel permeation chromatography.

Moreover, in this invention, it is preferable to use in the state of the water dispersion liquid which disperse | distributed urethane resin (A) in water. In this case, it is preferable to introduce a carboxy group and / or a sulfonic acid group into the urethane resin (A) from the viewpoint of good dispersibility in water.
It is more preferable to introduce a sulfonic acid group from the viewpoint that the radical polymerizable monomer mixture can be stably polymerized in the aqueous dispersion of the urethane resin (A). As a result, a dispersion (polymer dispersion) of polymer particles containing the urethane resin (A) having a sulfonic acid group and a polymer obtained from the radical polymerizable monomer mixture in the same particle is stably provided. Can be obtained. In particular, when the radical polymerizable monomer mixture includes an acid group-containing radical polymerizable monomer having an acid group such as a carboxy group, the polymerization stability during emulsion polymerization is improved. Further, the storage stability of the polymer dispersion and the storage stability when used as a coating material are improved, and a coating film having excellent water resistance and hydrolysis resistance can be formed.

The urethane resin (A) having a sulfonic acid group is a method of reacting a polyol such as a diol or a polyvalent isocyanate compound with a compound having a sulfonic acid group or a salt thereof; a polyol having a sulfonic acid group and a polyvalent isocyanate compound And the like.
Examples of the compound having a sulfonic acid group or a salt thereof include hydroxysulfonic acid such as 1,7-dihydroxynaphthalenesulfonic acid; 2,4-diaminobenzenesulfonic acid, 3,4-diaminobutanesulfonic acid, 3,6- Examples thereof include aminosulfonic acids such as diamino-2-toluenesulfonic acid and N- (2-aminoethyl) -2-aminoethylsulfonic acid. In the production of the urethane resin (A) having a sulfonic acid group, these compounds having a sulfonic acid group or a salt thereof may be used alone or in combination of two or more.
Examples of polyols having sulfonic acid groups include polyols containing sulfonic acid groups such as 1,4-butanediol-2-sulfonic acid; sulfonate-containing polyester polyols, sulfonate-containing polyether polyols, and sulfonate-containing polyols. Examples include sulfonate-containing polyols such as polycarbonate polyols. In the production of the urethane resin (A) having a sulfonic acid group, these polyols having a sulfonic acid group may be used alone or in combination of two or more.

The urethane resin (A) is preferably in the form of an aqueous dispersion as described above from the viewpoint that the radical polymerizable monomer mixture X can be polymerized stably. The average particle size of the urethane resin (A) in the aqueous dispersion is preferably 1000 nm or less, more preferably 500 nm or less, as the average particle size according to the cumulant analysis result. With such an average particle size, for example, the storage stability of the aqueous dispersion and the coating material, and the water resistance and solvent resistance of the coating film are further improved. The average particle size is preferably 10 nm or more from the viewpoints of paint viscosity characteristics and storage stability when used as a coating material.
The content of the urethane resin (A) in the aqueous dispersion is preferably 10% by mass or more, and more preferably 25% by mass or more. Moreover, it is preferable that it is 70 mass% or less, and it is more preferable that it is 60 mass% or less. With such a content, the solid content concentration of the polymer dispersion obtained by polymerizing the radical polymerizable monomer mixture X in the aqueous dispersion can be adjusted to a range of 10 to 80% by mass. If the solid content concentration of the polymer dispersion is within the above range, the paintability when this is used as a coating material will be good. The solid content concentration of the polymer dispersion is the amount of the polymer Z.

  As an aqueous dispersion of such a urethane resin (A), a commercially available urethane aqueous polymer dispersion (urethane dispersion: PUD) can be used as it is. Specifically, Daiichi Kogyo Seiyaku Co., Ltd .: Superflex 110, Superflex 150, Superflex 210, Superflex 300, Superflex 420, Superflex 460, Superflex 470, Superflex 500M, Superflex 620, Superflex 650, Superflex 740, Superflex 820, Superflex 840, F-8082D, F-2951D, manufactured by Sumika Bayer Urethane Co., Ltd .: Bihydrol UH2606, Bihydrol UH650, Bihydrol UHXP2648, Bihydrol UHXP2650, Implanil DLC-F , Implanille DLN, Implanille DLP-R, Implanille DLS, Implanille DL Impranil XP2611, Implanil LPRSC 1380, Implanil LPRSC1537, Implanil LPRSC1554, Implanil LPRSC3040, Implanil LPDSB1069, Dainippon Ink & Chemicals, Inc .: Hydran HW-301, HW-310, HW-311, HW- 312B, HW-333, HW-340, HW-350, HW-375, HW-920, HW-930, HW-940, HW-950, HW-970, AP-10, AP-20, ECOS3000, Sanyo Kasei Industrial Co., Ltd .: U-coat UWS-145, Permarin UA-150, Permarin UA-200, Permarin UA-300, Permarin UA-310, Ucourt UX-320, Permarin UA-368, Permal UA-385, Yukot UX-2510, manufactured by Nikka Chemical Co., Ltd .: Neo sticker 100C, Evaphanol HA-107C, Evaphanol HA-50C, Evaphanol HA-170, Evaphanol HA-560, ADEKA Corporation: Adekabon Examples include titer UHX-210 and Adekabon titer UHX-280.

[Radically polymerizable monomer mixture X and radical polymerizable monomer mixture Y]
A radically polymerizable monomer is a monomer having a radically polymerizable group, and a radically polymerizable group is a radically polymerizable carbon-carbon unsaturated double bond, a radically polymerizable carbon-carbon. A group containing an unsaturated triple bond, a ring capable of radical ring-opening polymerization and the like.
Examples of the radical polymerizable monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, and pentyl (meth). ) Acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl ( Alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms such as (meth) acrylate; cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylic Such as ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) ) Acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy-1,3-di (meth) acryloxy Propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl ] Propa 2,2-bis [4- (methacryloxy / polyethoxy) phenyl] propane, 2-hydroxy-1-acryloxy-3-methacryloxypropane, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di ( (Meth) acrylate, ethylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, propylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, diglycidyl ether of bisphenol A and hydroxyalkyl (meth) acrylate such as hydroxy (meth) acrylate Diester compounds of diol and (meth) acrylic acid such as epoxy (meth) acrylate to which is added, polyoxyalkylenated bisphenol A di (meth) acrylate, etc .; Tyrolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Dipentaerythritol hexa (meth) acrylate and other compounds having 3 or more hydroxyl groups per molecule and polyester compounds of (meth) acrylic acid; allyl (meth) acrylate, divinylbenzene, triallyl isocyanurate, iso (tele) Diallyl phthalate, diallyl isocyanurate, diallyl tris (2-acryloyloxyethylene) isocyanurate, ε-caprolactone modified tris (acryloxy) Chill) monomers having two or more radical polymerizable groups such as conjugated diene monomers such as isocyanurate, 1,3-butadiene and isoprene, acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid Acid group-containing radical polymerizable monomers such as β-carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Hydroxyl-containing radical polymerizable monomers such as hydroxyl-containing radical polymerizable monomers such as meth) acrylate, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, and the like Body: Methoxypolyethylene oxide mono (meth) acryl Alkyl-terminated polyalkylene oxide group-containing radical polymerizable monomers such as rate; Oxirane group-containing radical polymerizable monomers such as glycidyl (meth) acrylate; Carbonyl group-containing ethylenically unsaturated monomers such as diacetone acrylamide Body: 1,2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate, 2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate, etc. have light stabilizing action (meth) Acrylate; (meth) acrylate having ultraviolet absorbing component such as 2- [2′-hydroxy-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole; amino such as 2-aminoethyl (meth) acrylate Alkyl (meth) acrylates; amide group-containing radios such as (meth) acrylamide Polymerizable monomer; Metal-containing radical polymerizable monomer such as zinc di (meth) acrylate; Others such as (meth) acrylonitrile, benzyl (meth) acrylate, isobornyl (meth) acrylate, methoxyethyl (meth) acrylate, etc. (Meth) acrylic monomers; aromatic vinyl monomers such as styrene and methylstyrene; radical polymerizable monomers such as vinyl acetate, vinyl chloride, and ethylene. These may be used alone or in combination of two or more.

[Radically polymerizable monomer mixture X]
The radically polymerizable monomer mixture X of the present invention is a glass transition temperature of a polymer obtained by polymerizing the radically polymerizable monomer mixture X from the viewpoint of improving the storage stability of the polymer dispersion at low temperature. When (Tg) is Tg (X) (° C.) and the solubility parameter (SP value) by the Fedors method is SP (X) (J / cm ³ ) ^1/2 , the following formula (1) is satisfied. is necessary.
SP (X) ≧ −0.0125Tg (X) +19.875 Formula (1)
However, −60 ≦ Tg (X) (° C.) ≦ 170
Here, Tg (X) means a value obtained by the Fox equation of the following equation (2).
1 / (273 + Tg (X)) = Σ (Wi / (273 + Tgi)) (2)
In the formula, Wi represents a mass fraction of the radical polymerizable monomer i, and Tgi represents Tg (° C.) of a homopolymer of the radical polymerizable monomer i.
Here, SP (X) by the Fedors method means a value obtained by the following formula (3).
SP (X) = 1 / Σ (Wi / SPi) (3)
In the formula, SPi represents the SP value ((J / cm ³ ) ^1/2 ) of the radical polymerizable monomer i, and Wi represents the mass fraction of the radical polymerizable monomer i.
In the formulas (2) and (3), i is 1 to n when the radical polymerizable monomer mixture X is composed of n types of monomers.
For example, if the Tg of the radical polymerizable monomer mixture X is −50 ° C., the SP value of the radical polymerizable monomer mixture X needs to be 20.500 (J / cm ³ ) ^1/2 or more. When the Tg is 0 ° C., the SP value is 19.875 (J / cm ³ ) ^1/2 or more, and when the Tg is 50 ° C., 19.250 (J / cm ³ ) ^1/2 or more, Tg If it is 100 ° C., 18.625 (J / cm ³ ) ^1/2 or more is required, and if Tg is 150 ° C., 18.000 (J / cm ³ ) ^1/2 or more is required.

The formula (1) was determined by the following method.
(I) The types and / or contents (mass fraction) of the monomers constituting the radical polymerizable monomer mixture X are changed to prepare a plurality of types of radical polymerizable monomer mixtures X.
(Ii) With respect to each of the plurality of radical polymerizable monomer mixtures X obtained in (i) above, the glass transition temperature (Tg) of the polymer obtained by polymerizing the radical polymerizable monomer mixture X. A certain “Tg (X) (° C.)” and “SP (X) (J / cm ³ ) ^1/2 ”, which is a solubility parameter (SP value) by the Fedors method, are represented by the above formulas (2) and (3), respectively. Ask for.
(Iii) A plurality of types of radicals obtained in (i) above, wherein the horizontal axis is “Tg (X) (° C.)” and the vertical axis is “SP (X) (J / cm ³ ) ^1/2 ”. A graph in which each of the polymerizable monomer mixture X is plotted is created.
(Iv) The polymer dispersion liquid of the present invention is produced using each of the plural kinds of radical polymerizable monomer mixtures X obtained in (i).
(V) The plurality of polymer dispersions obtained in (iv) above are evaluated for low-temperature storage stability by [Method for evaluating low-temperature storage stability] described later, and the viscosity change rate is less than 150%. Is determined to be stable and those having a stability of 150% or more are determined to be unstable.
(Vi) (Tg (X), SP (X)) of the radical polymerizable monomer mixture X used in the production of the polymer dispersion determined to have good stability in the graph created in (iii) above. Satisfies the following formula (4), and (Tg (X), SP (X)) of the radical polymerizable monomer mixture X used in the production of the polymer dispersion determined to have poor stability is The expression (1) is obtained by determining the values of a and b in the expressions (4) and (5) so as to satisfy (5).
SP (X) ≧ a · Tg (X) + b (4)
SP (X) <a · Tg (X) + b (5)

Using the formula (1) obtained by determining a and b in this way, the composition (type and content of monomers) of the radical polymerizable monomer mixture X is set so as to satisfy the formula (1). By designing and producing the polymer dispersion liquid of the present invention using the radical polymerizable monomer mixture X having the designed composition, a polymer dispersion liquid excellent in low-temperature storage stability can be obtained.
The reason why such an effect is obtained is not clear, but the present inventors have found that the flexibility of the molecule in the polymer of the radical polymerizable monomer mixture X existing in the polymer dispersion (molecules at low temperature). It was thought that the ease of movement of the polymer dispersion had an effect on the viscosity increase during low temperature storage of the polymer dispersion. And as an index for evaluating the flexibility of the polymer molecules, paying attention to the glass transition temperature (Tg) of the polymer and the SP value related to the magnitude of the cohesive force (polarity) between the molecules of the polymer, When the steps (i) to (v) were performed, as shown in the Examples and Comparative Examples described later, the radical polymerizable monomer mixture X (Tg (X), SP (X)) and the low temperature A correlation was found between the storage stability evaluation results.
Therefore, using the formula (1) obtained based on the correlation, depending on whether the composition of the radical polymerizable monomer mixture X (monomer type and content) satisfies the formula (1), It can be predicted whether or not the low-temperature storage stability is good when the polymer dispersion of the present invention is produced using the radical polymerizable monomer mixture X. Further, when the low temperature storage stability is predicted to be poor without satisfying the formula (1), by adjusting the type and / or content (mass fraction) of the monomer so as to satisfy the formula (1) The radical polymerizable monomer mixture X suitable for the production of the polymer dispersion of the present invention can be obtained.

[Monomer (x1) / Monomer (x2)]
The radical polymerizable monomer mixture X includes a monomer (x1) having two or more radical polymerizable groups and a radical polymerizable monomer (x2) other than the monomer (x1). X is preferred.
By making the mixture, the urethane resin (A) and the radical are obtained by copolymerization of the monomer (x1) and the monomer (x2) impregnated in the urethane resin (A) in the step (1). A crosslinked structure can be introduced into the interior of the polymer P obtained by polymerizing the polymerizable monomer mixture X. Since the polymer P has a crosslinked structure, radical polymerization including the monomer (x1) and the monomer (x2) during the polymerization of the polymer P, after the polymerization, or in the finally obtained coating film It is possible to prevent the copolymer obtained from the polymerizable monomer mixture X and the urethane resin (A) from causing layer separation. As a result, it is possible to improve the water resistance, water absorption resistance, and hydrolysis resistance of the coating film without reducing the film forming property and solvent resistance, which are the features of the urethane resin (A).
Moreover, if the polymer P is a high molecular weight body which has a crosslinked structure, it can suppress that the radically polymerizable monomer mixture Y mentioned later impregnates and polymerizes inside the polymer P. As a result, it is possible to prepare a polymer Z in which the surface of the polymer P is coated with the polymer of the radical polymerizable monomer mixture Y. Thereby, the water resistance, water absorption resistance, hydrolysis resistance, resin compatibility, and coating machine washability of the finally obtained coating film are further improved, which is preferable.

Specific examples of the monomer (x1) include, for example, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (Meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy-1,3-di (meth) Acryloxypropane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (acryloxy polyethoxy) ) Phenyl] propane, 2, -Bis [4- (methacryloxy-polyethoxy) phenyl] propane, 2-hydroxy-1-acryloxy-3-methacryloxypropane, ethylene oxide-modified bisphenol A di (meth) acrylate, propylene oxide-modified bisphenol A di (meth) acrylate, Hydroxyalkyl (meth) acrylates such as hydroxy (meth) acrylate were added to ethylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, propylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, and diglycidyl ether of bisphenol A Diester compounds of diols such as epoxy (meth) acrylate and polyoxyalkylenated bisphenol A di (meth) acrylate and (meth) acrylic acid; Trimethylo Propanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, A compound having 3 or more hydroxyl groups per molecule such as dipentaerythritol hexa (meth) acrylate and a polyester compound of (meth) acrylic acid; allyl (meth) acrylate, divinylbenzene, triallyl isocyanurate, iso (tere) phthale Diallyl acid, diallyl isocyanurate, diallyl tris (2-acryloyloxyethylene) isocyanurate, ε-caprolactone modified tris (acryloxyethyl) Isocyanurate and the like.
Among them, it is preferable to use a radical polymerizable monomer having an allyl group such as allyl (meth) acrylate, triallyl isocyanurate, diallyl iso (tere) phthalate, diallyl isocyanurate, diallyl maleate and the like. Such a radically polymerizable monomer having an allyl group has a relatively low radical polymerization reactivity, and therefore, graft crosslinking with the radically polymerizable monomer mixture Y can occur. As a result, the polymer P obtained in the step (1) can be coated with the polymer of the radical polymerizable monomer mixture Y. Thereby, the solvent resistance of the finally obtained coating film and water resistance improve more.
A monomer (x1) may be used individually by 1 type, and may use 2 or more types together.

The content of the monomer (x1) in the mixture X is preferably 0.1 to 10% by mass and more preferably 0.5 to 8% by mass with respect to the total mass of the mixture X. 1 to 6% by mass is more preferable, and 2 to 4% by mass is most preferable.
If the content of the monomer (x1) in the mixture X is 0.1% by mass or more, a coating film excellent in solvent resistance and water resistance can be obtained. Moreover, if content of the monomer (x1) in the mixture X is 10 mass% or less, it was excellent in solvent resistance and water resistance, without reducing a softness | flexibility, freezing damage resistance, and chipping resistance. Since a coating film is obtained, it is preferable.

The radical polymerizable monomer (x2) other than the monomer (x1) is not particularly limited as long as it has the effect of the present invention. For example, from the above-mentioned examples of the radical polymerizable monomer, the monomer (x1) The remaining radically polymerizable monomers except for ()). These may be used alone or in combination of two or more.
The content of the monomer (x2) is preferably 90 to 99.9% by mass with respect to the total of 100% by mass of the monomer (x1) and the monomer (x2) in the mixture X. 92 More preferably, it is -99.5 mass%, 94-99 mass% is still more preferable, 96-98 mass% is the most preferable. If the content of the monomer (x2) is 90% by mass or more with respect to the total of 100% by mass of the monomer (x1) and the monomer (x2), the coating film has flexibility, frost resistance, If chipping is improved and the content of the monomer (x2) is 99.9% by mass or less, it is flexible without deteriorating the solvent resistance, water resistance, water absorption resistance and hydrolysis resistance of the coating film. , Frost resistance and chipping resistance are improved.

[Radically polymerizable monomer mixture Y]
The radical polymerizable monomer mixture Y is not particularly limited as long as it has the effects of the present invention, but the monomers exemplified in the above [Radical polymerizable monomer mixture X and radical polymerizable monomer mixture Y] are exemplified. It can be preferably used. These may be used alone or in combination of two or more. The radical polymerizable monomer mixture X used in step (1) may be used.
The radical polymerizable monomer mixture Y preferably further contains a hydroxyl group-containing radical polymerizable monomer from the following points.
By allowing the polymer Z to contain a hydroxyl group, it can undergo a crosslinking reaction with a curing agent such as a melamine crosslinking agent or an isocyanate curing agent, and the water resistance and solvent resistance of the resulting coating film are improved. Moreover, since the stability in the aqueous medium of the obtained polymer dispersion liquid, ie, the stability of the polymer Z in the coating material of this invention, improves, it is preferable.
Examples of such a hydroxyl group-containing radical polymerizable monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Monoesterified product of (meth) acrylic acid such as (meth) acrylate and C2-8 dihydric alcohol; ε- of monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol Examples include a caprolactone-modified product; N-hydroxymethyl (meth) acrylamide; allyl alcohol; and (meth) acrylate having a polyoxyethylene chain whose molecular terminal is a hydroxyl group. These monomers can be used alone or in combination of two or more.
Among the hydroxyl group-containing radical polymerizable monomers, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are among others. It can be preferably used.

In the present invention, the proportion of the hydroxyl group-containing radical polymerizable monomer used is determined from the viewpoint of the stability of the resulting polymer dispersion in an aqueous medium and the water resistance and solvent resistance of the resulting coating film from a urethane resin ( 0.1 to 10 parts by mass is preferable, 0.3 to 8 parts by mass is more preferable, and 0 to 10 parts by mass with respect to the total of 100 parts by mass of A) and the total amount of radical polymerizable monomers used up to step (2). It is particularly preferably 5 to 5 parts by mass.
Moreover, it is preferable to contain a carboxy-group containing radically polymerizable monomer as the radically polymerizable monomer mixture Y for the storage stability and mechanical stability of a polymer dispersion.
Examples of the carboxy group-containing radical polymerizable monomer include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, 2-acryloyloxypropionic acid and the like. These monomers can be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are preferably used from the viewpoint of polymerizability.
The proportion of the carboxyl group-containing radically polymerizable monomer used is determined from the viewpoint of the stability of the resulting polymer dispersion in the aqueous medium, from the urethane resin (A) and the radically polymerizable monomer used up to step (2). It is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and 0.2 to 3 parts by mass with respect to 100 parts by mass in total of the total mass. Particularly preferred.

<Step (1)>
Step (1) is a step of obtaining the polymer P by polymerizing the radical polymerizable monomer mixture X to the urethane resin (A).
The polymerization of the radical polymerizable monomer mixture can be performed by a known polymerization method such as a suspension polymerization method or an emulsion polymerization method. In particular, it is desirable to obtain a polymer dispersion in the form of an emulsion by an emulsion polymerization method from the viewpoints of storage stability of the coating material, water resistance of the coating film, solvent resistance, and the like.
For the emulsion polymerization, for example, a known method in which a radical polymerizable monomer mixture is supplied into a polymerization system in the presence of a surfactant and polymerization is performed with a radical polymerization initiator can be employed.
The method for supplying the radical polymerizable monomer mixture into the polymerization system is not particularly limited, a method for dropping the radical polymerizable monomer mixture; a method for adding the radical polymerizable monomer mixture at once; an interface A method of preparing a pre-emulsion solution in which a radical polymerizable monomer mixture is pre-emulsified and dispersed using an activator and water, and dropping the pre-emulsion solution; Can be mentioned.
In particular, in the step (1), it is preferable to adopt a method in which the radical polymerizable monomer mixture X is added all at once.
By introducing the radical polymerizable monomer mixture X all at once and performing emulsion polymerization, a polymer is uniformly formed inside the urethane resin (A) as compared with the drop polymerization, and this is because the polymerization is further performed collectively. Since a polymer can be made into a high molecular weight body, the water resistance and solvent resistance of the coating film are improved.

<Step (2)>
Step (2) is a step of obtaining the polymer Z by polymerizing the radical polymerizable monomer mixture Y with the polymer P obtained in the step (1).
As in step (1), the method for supplying the radical polymerizable monomer mixture into the polymerization system is not particularly limited, and a method for dropping the radical polymerizable monomer mixture; a radical polymerizable monomer mixture; A pre-emulsion in which a radical polymerizable monomer mixture is pre-emulsified and dispersed using a surfactant and water, and a method in which the pre-emulsion is dropped; the pre-emulsion The method of putting in a batch.
Especially in process (2), superposition | polymerization stability improves by carrying out emulsion polymerization by the method of dripping a pre-emulsion liquid.
From the above, it is preferable to adopt a method in which the radical polymerizable monomer mixture X is added all at once in the step (1) and a method in which the pre-emulsified liquid is dropped in the step (2).
It is preferable that at least one of the composition of the radically polymerizable monomer mixture to be used or the method for supplying the radically polymerizable monomer mixture is different between the step (1) and the step (2).

<Polymer Z>
The polymer Z is polymer particles obtained by polymerizing the polymer P with the radical polymerizable monomer mixture Y.
In the production method of the present invention, the mass ratio of the urethane resin (A) and the radical polymerizable monomer mixture X and Y is urethane resin (A) / radical polymerizable monomer mixture X and Y = (10 to 90). / (90 to 10) is preferable, (20 to 80) / (80 to 20) is more preferable, and (30 to 70) / (70 to 30) is particularly preferable. In this case, the total mass of the urethane resin (A) and the radical polymerizable monomer mixture X and Y is 100.
If the mass ratio of the urethane resin (A) is in the range of 10 to 90% by mass in the above-mentioned total mass of 100% by mass, the adhesiveness of the coating film is reduced without deteriorating the resin compatibility and the coating machine cleaning properties. In addition, water resistance and solvent resistance are improved. If it is the range of 20-70 mass% especially, the adhesiveness of a coating film will improve more.

<Polymerization initiator>
As the polymerization initiator used for the polymerization of the radical polymerizable monomer mixture X and Y, those generally used for radical polymerization can be used, for example, potassium persulfate, sodium persulfate, ammonium persulfate, etc. Persulfates, azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis ( Oil-soluble azo compounds such as 4-methoxy-2,4-dimethylvaleronitrile) and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile; 2,2′-azobis {2-methyl-N- [ 1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxyethyl)] propyl Pionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2′-azobis [2- (5-methyl-2-imidazoline-2- Yl) propane] and salts thereof, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and salts thereof, 2,2′-azobis [2- (3,4,5,6- Tetrahydropyrimidin-2-yl) propane] and salts thereof, 2,2′-azobis (1-imino-1-pyrrolidino-2-methylpropane) and salts thereof, 2,2′-azobis {2- [1- ( 2-hydroxyethyl) -2-imidazolin-2-yl] propane} and salts thereof, 2,2′-azobis (2-methylpropionamidine) and salts thereof, 2,2′-azobis [N- (2-carbox) Ethyl) -2-methylpropionamidine] and salts thereof; benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butylperoxy-2-ethylhexanoate, t- Examples thereof include organic peroxides such as butyl peroxyisobutyrate.

These initiators may be used alone or in combination of two or more.
It is preferable that the addition amount of the radical polymerization initiator used in the step (1) is 0.001 to 10 parts by mass with respect to 100 parts by mass of the total mass of the radical polymerizable monomer mixture X. Taking into consideration the progress of polymerization and control of the reaction, it is more preferably 0.005 to 10 parts by mass. Further, from the viewpoint of improving water resistance, solvent resistance, and weather resistance by increasing the molecular weight of the finally obtained polymer particles (polymer Z), the amount is more preferably 0.005 to 1 part by mass. Further, from the viewpoint of reducing the coarse particle ratio of the finally obtained polymer dispersion, it is more preferably 0.005 to 0.5 parts by mass, still more preferably 0.005 to 0.2 parts by mass, particularly preferably. Is 0.005 to 0.09 parts by mass.
Here, the “rough particle ratio” means that the polymer is coalesced during the polymerization and the average particle diameter is in the form of particles exceeding 1 μm. For example, the measurement of the particle diameter or after the polymerization Evaluation can be made by measuring the weight of the particulate polymer remaining on the mesh after filtration through a mesh or the like.
The addition amount of the radical polymerization initiator used in the step (2) and after is 0.01 to 10 parts by mass with respect to 100 parts by mass of the total mass of the radical polymerizable monomer mixture provided for each stage. preferable. Among these, it is more preferable that the amount is 0.02 to 5 parts by mass in consideration of polymerization progress and reaction control.

<Additives>
In the polymerization, it is preferable to use a reducing agent such as sodium bisulfite, ferrous sulfate, ascorbate or Rongalite in combination with the above radical polymerization initiator.
Among these, organic peroxides such as t-butyl hydroperoxide and the like from the point of progress of polymerization, wettability to the base material when coating the coating material, water resistance, weather resistance, solvent resistance of the coating film It is more preferable to employ a combination of ferrous sulfate, ascorbate and the like.
In the polymerization, an emulsifier can be used as necessary. When an emulsifier is used, the polymerization stability during emulsion polymerization can be improved, and aggregates can be reduced. In this case, the obtained polymer dispersion contains an emulsifier.
In general, the content of the emulsifier is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 100 parts by mass of the total mass of the radical polymerizable monomer mixture supplied to each stage. -5 parts by mass, more preferably 0.5-2 parts by mass.

As the emulsifier, the following anionic, cationic and nonionic surfactants and reactive surfactants can be used.
Anionic surfactants include potassium oleate, sodium laurate, sodium dodecylbenzene sulfonate, sodium alkane sulfonate, sodium alkyl naphthalene sulfonate, sodium dialkyl sulfosuccinate, polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl Non-reactive surfactants such as sodium allyl ether sulfate, polyoxyethylene alkyl phosphate ester, polyoxyethylene alkyl allyl phosphate ester, and alkyl allyl sulfosuccinate (eg, Sanyo Kasei Co., Ltd .: Eleminol (registered trademark) JS 2, JS-20, manufactured by Kao Corporation: LATEMUL (registered trademark) S-180A, S-180, etc.), polyoxyethylene alkylpropenyl phenyl ether Ammonium sulfate ammonium salt (for example, Aqualon (registered trademark) HS-10, HS-5, BC-10, BC-5 and the like manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), α-sulfo-ω- (1 -(Nonylphenoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl) ammonium salt (for example, manufactured by Asahi Denka Kogyo Co., Ltd .: Adecalia Soap (registered trademark) SE-) 10, SE-1025A, and the like), polyoxyethylene-1- (allyloxymethyl) alkyl ether sulfate ammonium salt (for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Aqualon (registered trademark) KH-10) Α-sulfo-ω- (1- (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanedi) Yl) ammonium salt (for example, manufactured by Asahi Denka Kogyo Co., Ltd .: Adecalia Soap (registered trademark) SR-10, SR-1025 etc.), polyoxyalkylene alkenyl ether ammonium sulfate salt (for example, manufactured by Kao Corporation) Reactive surfactants such as LATEMUL (registered trademark) PD-104).
Examples of the cationic surfactant include non-reactive surfactants such as stearylamine hydrochloride, lauryltrimethylammonium chloride, and trimethyloctadecylammonium chloride.
Nonionic surfactants include non-reactive surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethyleneoxypropyl block polymer, polyethylene glycol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, α- Hydro-ω- (1-alkoxymethyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl)) (Asahi Denka Kogyo Co., Ltd .: Adeka Soap ER-10, ER- 20, ER-30, ER-40), polyoxyethylene alkyl propenyl phenyl ether (Daiichi Kogyo Seiyaku Co., Ltd .: Aqualon RN-20, RN-30, RN-50), polyoxyalkyl alkenyl ether (Kao ( Co., Ltd .: Laterum PD-420, PD -430, PD-450) and the like.
Moreover, an amphoteric surfactant can also be used as an amphoteric component.
These emulsifiers can be used alone or in combination of two or more.
The polymer dispersion of the present invention is preferably adjusted to a pH of about 6.0 to 11.0 by adding a basic compound after polymerization. This improves the stability of the polymer dispersion and the storage stability of the coating material.
Examples of such basic compounds include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, 1-amino-2-propanol. 2-amino-1-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propyl Examples include aminoethanol, ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, and potassium hydroxide. Among these, from the viewpoint of the stability of the polymer dispersion, amine-based compounds are preferable, and 2-dimethylaminoethanol is preferably used.

<Polymer dispersion>
The polymer dispersion of the present invention contains the aforementioned polymer (Z) and a dispersion medium.
As the dispersion medium, those similar to those used in the aqueous coating material described later can be used.
The solid content concentration (polymer particle concentration) in the polymer dispersion of the present invention is preferably 10 to 80% by mass, more preferably 20 to 70% by mass. If the solid content concentration in the polymer dispersion is 10 to 80% by mass, it is preferable because it is easy to adjust the viscosity when the coating material is used and to adjust the final solid content.

The polymer (Z) is preferably in the form of particles. The average particle diameter of the particulate polymer (Z) (polymer particles) is 10 from the viewpoints of film formability, adhesion, water resistance, water absorption resistance, hydrolysis resistance, and solvent resistance of the coating film. It is preferably ˜1000 nm, more preferably 20 to 500 nm, and still more preferably 30 to 400 nm.
In the present specification, the average particle size of the polymer particles is a value calculated by cumulant analysis after measurement at room temperature using a dense particle size analyzer FPAR-1000 manufactured by Otsuka Electronics Co., Ltd.

<Coating material>
The coating material of the present invention contains a polymer dispersion, and preferably further contains various additives.
Examples of additives include various pigments, resin beads, antifoaming agents, pigment dispersants, leveling agents, anti-sagging agents, curing catalysts, matting agents, ultraviolet absorbers, light stabilizers, antioxidants, and heat resistance. Various additives such as an improver, a slip agent, a preservative, a plasticizer, a thickener, a wetting agent, and a solvent can be used, and one or more of these can be used.
Also, other polymer particles (for example, polyester resins, polyurethane resins, acrylic resins, acrylic silicone resins, silicone resins, fluorine resins, epoxy resins, polyolefin resins, alkyd resins, etc.) Dispersion particles made of other polymers), water-soluble resin / viscosity control agent, amino resin, polyisocyanate compound, blocked polyisocyanate compound, melamine resin, urea resin, carboxyl group-containing compound, carboxyl group-containing resin, epoxy group Curing agents such as containing resins, epoxy group-containing compounds, carbodiimide group-containing compounds may be mixed.

Examples of the pigment include a color pigment, an extender pigment, and a glitter pigment.
Examples of coloring pigments include titanium oxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, selenium pigments, and perylene pigments. Is mentioned.
Examples of extender pigments include clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white.
Examples of bright pigments include aluminum, copper, zinc, brass, nickel, aluminum oxide, mica, aluminum oxide coated with titanium oxide or iron oxide, mica coated with titanium oxide or iron oxide, glass flake, hologram And pigments.
One or more of these can be used.

The coating material of the present invention may further contain a solvent.
As the solvent, those usually used for water-based paints can be used. Examples of such a solvent include linear, branched or cyclic aliphatic alcohols having 5 to 14 carbon atoms; alcohols containing an aromatic group; general formula HO— (CH ₂ CHXO) _p — Represented by R ₄ (R ₄ is a linear or branched alkyl group having 1 to 10 carbon atoms, X is a hydrogen atom or a methyl group, and p is an integer of 5 or less). ) ethylene glycol or (poly) monoethers and propylene glycol; general formula _{R 5 COO- (CH 2 CHXO)} q -R 6 (R 5, R 6 is a straight-chain or branched having 1 to 10 carbon atoms X is a hydrogen atom or a methyl group, and q is an integer of 5 or less.) (Poly) ethylene glycol ether ester or (poly) propylene glycol ether Steal; aromatic organic solvents such as toluene and xylene; mono- or diisobutyrate of 2,2,4-trimethyl-1,3-pentanediol, 3-methoxybutanol, 3-methoxybutanol acetate, 3-methyl- Examples include 3-methoxybutanol and 3-methyl-3-methoxybutanol acetate.

Among these, linear, branched or cyclic aliphatic alcohols having 5 to 14 carbon atoms are preferable, alcohol based hydrophobic solvents having 7 to 14 carbon atoms are more preferable, 1-octanol, 2-octanol, Selected from the group consisting of 2-ethyl-1-hexanol, ethylene glycol mono 2-ethylhexyl ether, diethylene glycol mono n-butyl ether, propylene glycol mono n-butyl ether, dipropylene glycol mono n-methyl ether, dipropylene glycol mono n-butyl ether Particularly preferred are at least one alcoholic hydrophobic solvent.
The concentration of the polymer particles in the coating material is preferably 1 to 80% by mass, and more preferably 2 to 70% by mass. If it is this range, it is excellent in a coating-material viscosity characteristic, the water resistance of a coating film, and solvent resistance.
Further, when the coating material contains other polymer particles other than the polymer particles of the present invention, it is 5000 parts by mass or less with respect to 100 parts by mass of the polymer particles. Is preferred from the standpoints of resistance and solvent resistance.

<Painted object>
The coated product of the present invention is a coated product having a coating film coated with a coating material containing the polymer dispersion of the present invention.
There are no particular restrictions on the location where the coating material is applied to form the coating film, and various articles (hereinafter referred to as “substrate” for convenience) can be formed into a coated product.
Examples of the substrate include, for example, an outer plate part of an automobile body, an automobile interior base material, an outer plate part of a household electric product, cement mortar, a slate plate, a gypsum board, an extruded plate, an expandable concrete, a metal, glass, a porcelain tile, Examples include asphalt, wood, waterproof rubber material, plastic, calcium silicate base material, PVC sheet, FRP (Fiber Reinforced Plastics), natural leather, synthetic leather, and fiber.
Specific examples of the paint having a coating film obtained by applying the coating material of the present invention include, for example, interior / exterior of passenger cars, trucks, motorcycles, buses, building materials, interior / exterior of buildings, window frames, window glass, structures Examples include materials, plates, exteriors of machinery and equipment, bridges, guardrails, tents, greenhouses, blinds, roofing materials, housing equipment, refrigerators, air conditioners, televisions, lighting fixtures, kitchenware, functional fibers, and the like.

<Formation method of coating film>
Examples of methods for applying the coating material to the surface of various substrates include air spray coating, airless spray coating, rotary atomization coating, curtain coating, roller coating, bar coating, air knife coating, brush coating, and dipping. Various coating methods such as painting can be selected as appropriate.
The coating amount of the coating material of the present invention is the thickness after drying of the coating film obtained by applying the coating material, and is usually preferably about 0.1 to 100 μm, more preferably 1 to 50 μm. An amount of 10 to 40 μm is preferable.
Moreover, it is preferable to perform the drying temperature after application | coating at normal temperature drying (5-35 degreeC) or 40-200 degreeC.

When the coating material is formed by heat curing, it is preferable to perform preheating, air blowing, or the like under heating conditions in which the coating film is not substantially cured from the viewpoint of preventing the occurrence of coating film defects such as “waki”. Among these, it is more preferable to perform preheating from the viewpoint of enabling faster film formation.
The preheating temperature is preferably 40 to 100 ° C, more preferably 50 to 90 ° C, and particularly preferably 60 to 80 ° C.
The preheating time is preferably about 30 seconds to 15 minutes, more preferably 1 to 10 minutes, and particularly preferably 2 to 5 minutes.
After preheating under the above-mentioned conditions, the coating material can be heated and cured by a known heating means to form a coating film. As a known heating means, for example, a drying furnace such as a hot air furnace, an electric furnace, or an infrared induction heating furnace can be used. The heating temperature is usually preferably 40 to 200 ° C, more preferably 60 to 180 ° C, and particularly preferably 80 to 160 ° C. The heating time is not particularly limited as long as it has the effect of the present invention, but is usually about 10 to 60 minutes, particularly preferably about 20 to 40 minutes.
By the method described above, the coated product formed with the coating material of the present invention can exhibit excellent coating film appearance and solvent resistance, water resistance, water absorption resistance, and hydrolysis resistance. .

<Coating film obtained from polymer dispersion>
The coating film obtained from the polymer dispersion of the present invention has at least one or more when measured with a thermal flow rate differential scanning calorimeter (DSC) under the following conditions from the viewpoints of hardness, water resistance, and solvent resistance of the coating film. It is preferable to have the endothermic peak.
(Measuring method)
Using a coating film obtained from a dispersion containing the polymer Z, measurement is performed at a temperature increase rate of 10 ° C./min from −100 ° C. to 100 ° C. using a thermal flow rate differential scanning calorimetry system (DSC).
This endothermic peak means a melting point peak of crystals, and is observed when, for example, a urethane resin (A) having crystallinity is used.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not limited to these Examples.
Unless otherwise specified, “part” in this example means “part by mass”, and “%” means “mass%”. In addition, measurement, evaluation, and the like of the polymer dispersion and the coating material in this example were performed by the following methods.
In addition, Tables 1 to 3 show the number of blended parts of each component when the polymer dispersion was produced in each example and the evaluation results in each example.

[Method for evaluating low-temperature storage stability]
The polymer dispersion whose viscosity was measured in advance was allowed to stand in a 5 ° C. atmosphere for 1 month and then left in a thermostatic bath at 25 ° C. for 3 hours. When the temperature reached 25 ° C., the B-type viscometer The viscosity change rate was measured, and the viscosity change rate was calculated from the following formula (3).
A = {(η2−η1) / η1} × 100
Here, the symbol in a formula shows the following values.
A: Viscosity change rate (%)
η1: Initial viscosity (mPa · s, 60 rpm)
η2: Viscosity after standing at 5 ° C. × 1 month (mPa · s, 60 rpm)
The low temperature storage stability was determined according to the following criteria.
(Viscosity change rate)
“◎”: Less than 100% “O”: 100% or more and less than 150% “×”: 150% or more

[Example 1]
(Preparation of polymer dispersion)
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, a polyester-based urethane polymer (trade name: Implanil LP RSC 3040, manufactured by Sumika Bayer Urethane Co., Ltd., solid) as a urethane resin (A) 40%): 75 parts (solid content 30 parts), deionized water: 72.3 parts, Neocor SWC (anionic surfactant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., solid content 70%): 0.44 Parts (solid content: 0.31 parts), Adeka Soap ER-10 (nonionic surfactant, manufactured by ADEKA Corporation): 0.44 parts, radical polymerizable monomer mixture X as ethyl acrylate: 49. 4 parts were charged and the flask was heated to 50 ° C. Then, t-butyl hydroperoxide aqueous solution (trade name: Kayabutyl H70, manufactured by Kayaku Akzo Co., Ltd.): 0.014 part, deionized water: 0.7 part as a polymerization initiator, and sulfuric acid as a reducing agent. Ferrous iron: 0.00014 parts, ethylenediaminetetraacetic acid (EDTA): 0.00019 parts, sodium ascorbate: 0.014 parts, deionized water: 0.7 parts. Further, after confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was raised to 75 ° C. and held for 20 minutes.
Next, 0.07 parts of sodium ascorbate and 3.51 parts of deionized water were added as reducing agents to the dispersion and kept at 75 ° C. for 10 minutes. Then, methyl methacrylate: 11 parts, 2- Ethylhexyl acrylate: 7.4 parts, 2-hydroxyethyl methacrylate: 1 part, allyl methacrylate: 0.7 parts, 80% acrylic acid: 0.5 parts, Neocor SW-C: 0.33 parts (solid content 0.23) Part), Adekaria soap ER-10: 0.33 part, deionized water: 18. A pre-emulsion liquid obtained by emulsifying and dispersing the radical polymerizable monomer mixture Y in advance, and t-butyl hydroperoxide A polymerization initiator aqueous solution containing an aqueous solution: 0.021 parts and deionized water: 6.31 parts was added dropwise over 1 hour. During the dropwise addition, the internal temperature of the flask was maintained at 75 ° C., and was maintained at 75 ° C. for 1.5 hours after the completion of the dropwise addition. Thereafter, the reaction solution was cooled to room temperature, and dimethylaminoethanol: 0.52 parts and deionized water: 4.21 parts were added as an aqueous amine solution to obtain a polymer dispersion of the present invention. Table 1 shows the results of the low-temperature storage stability test of the obtained polymer dispersion.

[Examples 2-14, Comparative Examples 1-3]
As shown in Tables 1 to 3, a polymer dispersion was prepared in the same manner as in Example 1 except that each component was changed. Table 3 shows the low-temperature storage stability test results of the obtained polymer dispersion.

However, the abbreviations in Tables 1 to 3 indicate the following compounds.
Urethane resin (A1): Implanil LP RSC 3040 (manufactured by Sumika Bayer Urethane Co., Ltd., with crystallinity).
Urethane resin (A2): Implanil XP2772 (manufactured by Sumika Bayer Urethane Co., Ltd., with crystallinity).
AMA: allyl methacrylate (Tg: 52 ° C., SP value: 23.09).
IBXMA: isobornyl methacrylate (Tg: 155 ° C., SP value: 18.87).
TBMA: t-butyl methacrylate (Tg: 107 ° C., SP value: 18.32).
MMA: methyl methacrylate (Tg: 105 ° C., SP value: 20.15).
MA: Methyl acrylate (Tg: 8 ° C., SP value: 21.38).
-EA: Ethyl acrylate (Tg: -22 ° C, SP value 20.48).
BA: n-butyl acrylate (Tg: -52 ° C, SP value: 19.73).
2-EHA: 2-ethylhexyl acrylate (Tg: -70 ° C, SP value: 18.83).
2-HEMA: 2-hydroxyethyl methacrylate (Tg: 55 ° C., SP value: 24.98).
AA: acrylic acid (Tg: 106 ° C., SP value: 25.70).

FIG. 1 is a graph plotting Tg (X) and SP (X) of the radical polymerizable monomer mixture X used in Examples and Comparative Examples. The formula of the straight line in the graph is SP (X) = − 0.0125Tg (X) +19.875.
From the results of Tables 1 to 3 and FIG. 1, in Examples 1 to 14, Tg (X) and SP (X) of the radical polymerizable monomer mixture X used for the production of the polymer dispersion were SP (X ) ≧ −0.0125 Tg (X) +19.875 (Formula 1) The obtained polymer dispersion was excellent in low-temperature storage stability.
In Comparative Examples 1 to 3, Tg (X) and SP (X) of the radical polymerizable monomer mixture X used for the production of the polymer dispersion were SP (X) ≧ −0.0125Tg (X) +19. This is an example that does not satisfy 875 (Formula 1), and the low-temperature storage stability was poor.

The polymer dispersion obtained by the production method of the present invention is excellent in low-temperature storage stability, and the coating film coated with the coating material containing the polymer dispersion of the present invention exhibits excellent water resistance and solvent resistance. be able to. In particular, a coating film excellent in water resistance and solvent resistance can be obtained even with a dried coating film obtained under conditions where the drying conditions are insufficient such as low temperature and short time evaporation of water and solvent, and insufficient fusion of particles.
Therefore, it can be used for various coating applications such as protection of body parts of automobile car bodies such as passenger cars, trucks, motorcycles, buses, automobile parts, buildings, civil engineering structures, and design. Very useful.

Claims (5)

In the step (1) of obtaining a dispersion containing the polymer P by polymerizing the urethane resin (A) and one or more kinds of radically polymerizable monomer mixture X, A step (2) of adding a radically polymerizable monomer mixture Y of at least one species to perform polymerization to obtain a dispersion containing the polymer Z, and
The glass transition temperature of the polymer obtained by polymerizing the radical polymerizable monomer mixture X is Tg (X) [unit: ° C.] determined by the FOX equation, and the solubility parameter (SP value) by the Fedors method is used. A method for producing a polymer dispersion, in which, when SP (X) [unit: (J / cm ³ ) ^1/2 ], the Tg (X) and SP (X) satisfy the following formula (1).
SP (X) ≧ −0.0125Tg (X) +19.875 (1)
However, −60 ≦ Tg (X) ≦ 170.   The radical polymerizable monomer mixture X includes a monomer (x1) having two or more radical polymerizable groups and a radical polymerizable monomer (x2) other than the monomer (x1). The method for producing a polymer dispersion according to claim 1, which is a mixture.   A polymer dispersion obtained by the production method according to claim 1.   A coating material comprising the polymer dispersion according to claim 3.   A coated article to which the coating material according to claim 4 is applied.

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