JP2013189559A - Aqueous resin composition and steel sheet surface treatment agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous resin composition capable of forming a coating film which is excellent storage stability, excellent water resistance and adhesion to a base material, and to provide a steel sheet surface treatment agent.SOLUTION: There are provided an aqueous resin composition obtained by dispersion in an aqueous medium (B) with composite resin particles (A) composed of a cationic urethane resin (a1) represented by formula [I] and a vinyl polymer (a2), and a steel sheet surface treatment agent.

Description

  The present invention relates to an aqueous resin composition that can be used in various applications such as a coating agent and an adhesive including a steel sheet surface treating agent.

  The coating agent is required to be able to form a coating film capable of imparting design properties and the like to various substrate surfaces and imparting a protective function and the like of the substrate surface. For example, in recent years, with the increase in demand for metals, the demand for coating agents for surface protection of metal base materials such as steel plates has also increased, and such coating agents are excellent from the viewpoint of preventing metal rust and the like. It is demanded that a coating film having water resistance can be formed.

  As a coating agent for surface protection of the metal substrate, there are usually many containing a rust inhibitor such as phosphate, and the rust preventive agent imparts excellent rust prevention properties to the formed coating film. Yes.

  However, the phosphate and the like are sufficiently unstable in terms of storage stability, for example, they become electronically unstable in the presence of an anionic resin as a binder resin for the coating agent, resulting in the formation of aggregates and the like. There was no case.

  Therefore, as the coating agent, it has been studied to use a cationic resin as a binder resin. For example, one or more vinyl monomers are used as a free radical initiator in water in which cationically stabilized polyurethane is present as an emulsifier. Aqueous dispersions obtained by emulsion polymerization with a polymer are known (for example, see Patent Document 1).

  However, the coating film formed using the aqueous dispersion is not yet sufficient in terms of adhesion to various substrates including metal substrates, and water resistance may not be of a practically sufficient level. there were. Moreover, since the aqueous dispersion may cause the generation of aggregates due to long-term storage or the like, it may not be sufficient in terms of storage stability.

Japanese National Patent Publication No. 10-511417

  The problem to be solved by the present invention is to provide an aqueous resin composition which is excellent in storage stability and capable of forming a coating film excellent in water resistance and substrate adhesion.

  As a result of investigations to solve the above problems, the present inventors have compounded different resins such as a urethane resin and a vinyl polymer, and the urethane resin has a specific cation having a cationic group in a side chain. It has been found that an aqueous resin composition obtained by using a combination of water-soluble urethane resins can achieve both excellent storage stability in an aqueous medium and excellent adhesion and water resistance of a coating film to be formed.

  That is, in the present invention, the composite resin particle (A) composed of the cationic urethane resin (a1) having the structure represented by the following general formula [I] and the vinyl polymer (a2) is used as the aqueous medium (B). The present invention relates to a water-based resin composition and a steel sheet surface treatment agent characterized by being dispersed in a steel sheet.

[In the formula [I], R ¹ represents an alkylene group having an aliphatic or aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ² and R ³ are independently of each other. An alkyl group having an aliphatic or aliphatic cyclic structure, R ⁴ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ]

  If it is the aqueous resin composition of the present invention, it is possible to achieve both excellent storage stability in an aqueous medium and excellent water resistance and substrate adhesion of the coating film to be formed. Can be used in a wide range of fields such as coating agents and adhesives.

  In the aqueous resin composition of the present invention, composite resin particles (A) composed of a cationic urethane resin (a1) having a structure represented by the following general formula [I] and a vinyl polymer (a2) are contained in an aqueous medium. It is dispersed in (B).

First, the composite resin particle (A) will be described.
The composite resin particle (A) used in the present invention contains a cationic urethane resin (a1) and the vinyl polymer (a2). The cationic urethane resin (a1) and the vinyl polymer (a2) do not exist independently in the aqueous medium (B), but inside the resin particles formed by the cationic urethane resin (a1). It is preferable that a part or all of the vinyl polymer (a2) is inherently formed to form composite resin particles (A). More specifically, the vinyl polymer (a2) is preferably dispersed in the cationic urethane resin (a1) particles in the form of a single particle or a plurality of particles, and the cation as a shell layer is preferable. It is preferable to form core / shell type composite resin particles composed of the conductive urethane resin (a1) and the vinyl polymer (a2) as the core layer. As the composite resin particles (A), it is preferable that the vinyl polymer (a2) is almost completely covered with the cationic urethane resin (a1). A part of the vinyl polymer (a2) may be present on the outermost part of the composite resin particle (A) as long as it is not damaged.

  On the other hand, the cationic urethane resin (a1) and the vinyl polymer (a2) do not form the composite resin particles (A), but are each separately dispersed in the aqueous medium (B) independently. Then, there are cases where excellent water resistance and substrate adhesion cannot be imparted.

  The cationic urethane resin (a1) and the vinyl polymer (a2) are not chemically bonded from the viewpoint of forming a coating film excellent in water resistance and substrate adhesion. Is preferred.

  Here, the term “not chemically bonded” means that the inside of the composite resin particle (A), specifically the cationic urethane resin (a1) constituting the shell layer and the vinyl weight forming the core layer. It refers to a state in which a covalent bond is not formed with the union (a2) or a minute covalent bond is formed so as not to inhibit the effect of the aqueous resin composition of the present invention. The crosslink density inside the composite resin particles (A) improves the film-forming property without impairing the good storage stability of the aqueous resin composition of the present invention, and is excellent in water resistance, substrate adhesion, and the like. In forming the film, it is preferably as low as possible, and more preferably not forming the chemical bond.

  The degree of crosslinking inside the composite resin particles (A) can be evaluated by examining the ease of dissolution of the composite resin particles (A) in an organic solvent. Specifically, as will be described later in Examples, the evaluation can be made based on the light transmittance (transparency) of the mixed liquid of the composite resin particle (A) in water and tetrahydrofuran. When the light transmittance (wavelength 640 nm) of the mixed liquid having a concentration of the composite resin particles (A) of 4% by mass is 70% or more, no cross-linked structure is formed inside the composite resin particles (A). Even if a crosslinked structure is formed, the degree is very small, and it can be said that the crosslinked structure is not substantially formed.

  The light transmittance may not be 100% even when no cross-linked structure is formed inside the composite resin particles (A). This is thought to be due to entanglement between molecular chains. Therefore, even if the light transmittance is less than 100%, a crosslinked structure may not be formed inside the composite particle.

  The composite resin particle (A) has an excellent film-forming property without impairing excellent storage stability, and in obtaining an aqueous resin composition capable of forming a coating film excellent in water resistance and substrate adhesion, The average particle size is preferably in the range of 5 nm to 100 nm. The average particle diameter here refers to an average particle diameter on a volume basis measured by a dynamic light scattering method, as will be described later in Examples.

  Moreover, as said composite resin particle (A), mass ratio [(a1) / (a2)] of the said cationic urethane resin (a1) and the said vinyl polymer (a2) is 10 / 90-70 / 30. It is preferable to use some, and using 20/80 to 55/45 is excellent in film-forming properties and excellent in water resistance and substrate adhesion without impairing good storage stability. It is especially preferable when obtaining the aqueous resin composition which can form a coating film.

  The composite resin particles (A) have a hydrophilic group necessary for dispersion in the aqueous medium (B). The hydrophilic group is preferably supplied by the cationic urethane resin (a1).

  As the cationic group as the hydrophilic group, for example, a tertiary amino group or the like can be used. The tertiary amino group may be partially or entirely neutralized with acetic acid or propionic acid.

  The cationic group is present in a range of 50 mmol / kg to 1,000 mmol / kg with respect to the entire composite resin particle (A), so that good water of the composite resin particle (A) in the aqueous medium (B) can be obtained. It is preferable for imparting dispersion stability.

  Next, the cationic urethane resin (a1) that forms the composite resin particles (A) will be described.

  The cationic urethane resin (a1) constituting the composite resin particle (A) has a structure represented by the following general formula [I].

[Wherein, R ¹ represents an alkylene group having an aliphatic or aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ² and R ³ independently represent an aliphatic or An alkyl group having an aliphatic cyclic structure, R ⁴ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ]

  The structure represented by the general formula [I] is an essential structure for imparting water dispersibility to the cationic urethane resin (a1) and improving the water resistance of the resulting coating film.

  Here, in place of the cationic urethane resin (a1), a cationic urethane resin not having the structure represented by the general formula [I] is used, and the other aqueous solutions obtained with the same composition as the present invention. The resin composition may not be able to achieve both excellent storage stability and excellent water resistance of the coating film.

  It is preferable that the cationic amino group which the structure shown by the said general formula [I] has is contained in 0.005-1.5 equivalent / kg with respect to the said cationic urethane resin (a1) whole quantity.

  Moreover, the said cationic urethane resin (a1) may have 1 or more types chosen from the group which consists of a hydrolysable silyl group and a silanol group.

  The hydrolyzable silyl group is a functional group in which the hydrolyzable group is directly bonded to a silicon atom, and examples thereof include a functional group represented by the following general formula. The hydrolyzable silyl group becomes a silanol group to be described later by being hydrolyzed.

(In the formula [II], R ⁵ is a monovalent organic group such as an alkyl group, aryl group or aralkyl group, and R ⁶ is a halogen atom, alkoxy group, acyloxy group, phenoxy group, aryloxy group, mercapto group, amino group. A group, an amide group, an aminooxy group, an iminooxy group or an alkenyloxy group, and x is an integer of 0 to 2.)

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a neopentyl group, a 1-methylbutyl group, a 2-methylbutyl group, a hexyl group, and an isohexyl group. It is done.

  Examples of the aryl group include a phenyl group, a naphthyl group, and a 2-methylphenyl group. Examples of the aralkyl group include a benzyl group, a diphenylmethyl group, and a naphthylmethyl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group.

  Examples of the acyloxy group include acetoxy, propanoyloxy, butanoyloxy, phenylacetoxy, acetoacetoxy, and the like. Examples of the aryloxy group include phenyloxy, naphthyloxy, and the like. Examples of the group include an allyloxy group, a 1-propenyloxy group, and an isopropenyloxy group.

R ⁶ is preferably an alkoxy group from the viewpoint of suppressing the degree of cross-linking inside the composite resin particles (A) to a low level and allowing the cross-linking to proceed during the formation of the coating film, and in particular, an ethoxy group, a propoxy group, It is preferably an isopropoxy group or a butoxy group.

  The silanol group is a functional group in which a hydroxyl group is directly bonded to a silicon atom, and is a functional group mainly generated by hydrolysis of the hydrolyzable silyl group described above.

  The hydrolyzable silyl group or silanol group is preferably a relatively bulky functional group such as a triisopropoxysilyl group, a methyldiethoxysilyl group, or a methyldiisopropoxysilyl group.

  The aqueous resin composition containing the composite resin particle (A) having such a functional group has a more excellent water resistance and the like because a crosslinking reaction proceeds between the functional groups of the hydrolyzable silyl group or silanol group. It is possible to form the coating film which has. Moreover, the said hydrolysable silyl group or silanol group can improve the adhesiveness with respect to the metal base material of a coating film, and can further improve the corrosion resistance of a coating film.

  The hydrolyzable silyl group and silanol group are present in an amount of 10 mmol / kg to 400 mmol / kg based on the whole of the cationic urethane resin (a1). It is preferable when obtaining the formable aqueous resin composition.

  The cationic urethane resin (a1) preferably has a weight average molecular weight in the range of 5,000 to 500,000, preferably 20,000 to 100,000. It is preferable when obtaining the aqueous resin composition which is excellent in film forming property and can form the coating film excellent in water resistance.

Next, the vinyl polymer (a2) constituting the composite resin particle (A) will be described.
Use of the vinyl polymer (a2) constituting the composite resin particle (A) in combination with the cationic urethane resin (a1) is essential for achieving the effects of the present invention. Here, the aqueous resin composition containing resin particles or the like using only the vinyl polymer (a2) may have insufficient substrate adhesion to a metal or the like. In addition, in an aqueous resin composition containing resin particles or the like using only the cationic urethane resin (a1), the heat discoloration may be insufficient.

  As the vinyl polymer (a2), one having an acid group, a silicon atom-containing group or the like is preferably used for forming a coating film having excellent substrate adhesion, corrosion resistance, alkali resistance, and the like.

  As the acid group, a carboxyl group or a sulfonic acid group, a carboxylate group or a sulfonate group in which they are neutralized with a basic compound or the like can be used.

  Moreover, as said silicon atom containing group, the thing similar to the functional group represented by the said general formula (II) illustrated as a functional group which the said cationic urethane resin (a1) may have is mentioned, for example. It is done.

  Moreover, it is preferable that the vinyl polymer (a2) is a (meth) acrylic acid ester copolymer because a coating film having further excellent water resistance can be formed.

  The weight average molecular weight of the vinyl polymer (a2) is preferably in the range of 100,000 to 2,000,000 from the viewpoint of improving the water resistance of the coating film.

Next, a method for producing the composite resin particle (A) will be described.
The composite resin particles (A) include, for example, a step (W) of producing an aqueous dispersion of a cationic urethane resin (a1), and a vinyl polymer (a2) obtained by polymerizing a vinyl monomer in the aqueous dispersion. It can manufacture by process (X) which manufactures.

First, the step (W) will be described.
The step (W) includes a step of producing a cationic urethane resin (a1), and a step of dispersing the cationic urethane resin (a1) obtained above in an aqueous medium (B) to obtain an aqueous dispersion. .

  The cationic urethane resin (a1) is, for example, a compound having two epoxy groups in one molecule represented by the following general formula [III] in the absence of a solvent, in the presence of an organic solvent, or in the presence of a reactive diluent. A polyol (a2-4) containing a tertiary amino group-containing polyol (a2-3) obtained by reacting (a2-1) with a secondary amine (a2-2), and a polyisocyanate (a2-5) described later ).

[In Formula [III], R ⁷ represents an alkylene group having an aliphatic or aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group. ]

  The tertiary amino group-containing polyol (a2-3) contains a neutral salt of a tertiary amino group and a cationic group such as a quaternary amino group for imparting water dispersibility to the resulting urethane resin. It is a compound used for introduction into the side chain. The tertiary amino group-containing polyol (a2-3) generates a cationic group by neutralizing the tertiary amino group contained in the molecule with an acid or quaternizing with a quaternizing agent. Is a precursor.

  The tertiary amino group-containing polyol (a2-3) includes, for example, a compound (a2-1) having two epoxy groups in one molecule and a secondary amine (a2-2) with respect to 1 equivalent of epoxy group. Thus, it is easily obtained by adding a ring-opening addition reaction at room temperature or under heating without using a catalyst.

  As the compound (a2-1) having two epoxy groups in one molecule represented by the general formula [III], the following compounds can be used.

Examples of the group in which R ₁ is an alkylene group having an aliphatic or aliphatic cyclic structure include ethanediol-1,2-diglycidyl ether, propanediol-1,2-diglycidyl ether, propanediol-1 , 3-diglycidyl ether, butanediol-1,4-diglycidyl ether, pentanediol-1,5-diglycidyl ether, 3-methyl-pentanediol-1,5-diglycidyl ether, neopentyl glycol-diglycidyl Ether, hexanediol-1,6-diglycidyl ether, polybutadiene-diglycidyl ether, cyclohexane-1,4-diglycidyl ether, 2,2-bis (4-hydroxycyclohexyl) -propane (hydrogenated bisphenol A) Glycidyl ether, water Diglycidyl ether of (hydrogenated bisphenol F), which is an isomer mixture of elementally added dihydroxydiphenylmethane, can be used.

Examples of those in which R ₁ is a residue of a dihydric phenol include, for example, resorcinol-diglycidyl ether, hydroquinone-diglycidyl ether, 2,2-bis (4-hydroxyphenyl) -propane (bisphenol A) Diglycidyl ether, diglycidyl ether of isomer mixture of dihydroxydiphenylmethane (bisphenol F), diglycidyl ether of 4,4-dihydroxy-3-3'-dimethyldiphenylpropane, diglycidyl ether of 4,4-dihydroxydiphenylcyclohexane, 4 , 4-dihydroxydiphenyl diglycidyl ether, 4,4-dihydroxydibenzophenone diglycidyl ether, bis (4-hydroxyphenyl) -1,1-ethane diglycidyl ether, bis (4-hydroxy Phenyl) -1,1-isobutane diglycidyl ether, bis (4-hydroxy-3-tert-butylphenyl) -2,2-propane diglycidyl ether, bis (2-hydroxynaphthyl) methane diglycidyl ether, Diglycidyl ether of bis (4-hydroxyphenyl) sulfone (bisphenol S) or the like can be used.

Examples of the group in which R ₁ is a polyoxyalkylene group include diethylene glycol-diglycidyl ether, dipropylene glycol-diglycidyl ether, and polyoxyalkylene glycol-diglycidyl ether having 3 to 60 repeating units of oxyalkylene. For example, polyoxyethylene glycol-diglycidyl ether and polyoxypropylene glycol-diglycidyl ether, diglycidyl ether of ethylene oxide-propylene oxide copolymer, polyoxytetraethylene glycol-diglycidyl ether, etc. can be used. .

Among these, since the water dispersibility of the cationic urethane resin (a1) can be further improved and the alkali resistance and the heat discoloration can be improved, R _{1 in the} general formula [III] is a polyoxyalkylene group. Preferred are diglycidyl ethers of certain polyoxyalkylene glycols, in particular polyethylene glycol-diglycidyl ether and / or polypropylene glycol-diglycidyl ether, and / or diglycidyl ether of ethylene oxide-propylene oxide copolymer.

The epoxy equivalent of the diglycidyl ether of polyoxyalkylene glycol in which R ₁ of the general formula [III] is a polyoxyalkylene group is used for various physical properties and thermal properties of the cationic urethane resin aqueous dispersion. Is preferably 1000 g / equivalent or less, more preferably 500 g / equivalent or less, and particularly preferably, in that the cationic concentration in the cationic urethane resin (a1) aqueous dispersion can be designed over a wide range. 300 g / equivalent or less.

  Moreover, as said secondary amine (a2-2), although a well-known compound can be used, a branched or linear aliphatic secondary amine is preferable at the point of the ease of reaction control.

  Examples of such secondary amine that can be used include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, di-tert-butylamine, di-sec-butylamine, di-n. -Pentylamine, di-n-peptylamine, di-n-octylamine, diisooctylamine, dinonylamine, diisononylamine, di-n-decylamine, di-n-undecylamine, di-n-dodecylamine, di- Examples include n-pentadecylamine, di-n-octadecylamine, di-n-nonadecylamine, and di-n-eicosylamine.

  Among these, it is difficult to volatilize when producing the tertiary amino group-containing polyol (a2-3), or a part or all of the contained tertiary amino group is neutralized with an acid, or a quaternizing agent. In view of the fact that steric hindrance can be reduced when quaternization is carried out, an aliphatic secondary amine having 2 to 18 carbon atoms is preferable, and an aliphatic secondary amine having 3 to 8 carbon atoms is more preferable. .

  A tertiary amino group-containing polyol (a2) is obtained by neutralizing part or all of the tertiary amino group of the tertiary amino group-containing polyol (a2-3) with an acid or quaternizing with a quaternizing agent. -3) and the polyisocyanate (a2-4) can impart water dispersibility to the cationic urethane resin (a1) obtained.

  Examples of the acid that can be used for neutralizing part or all of the tertiary amino group include formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, butyric acid, lactic acid, malic acid, and citric acid. , Organic acids such as tartaric acid, malonic acid, adipic acid, organic sulfonic acids such as sulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, phosphorous acid, hydrofluoric acid Inorganic acids such as can be used.

  Examples of the quaternizing agent that can be used for quaternizing a part or all of the tertiary amino group include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, methyl chloride, and ethyl chloride. Alkyl halides such as benzyl chloride, methyl bromide, ethyl bromide, benzyl bromide, methyl iodide, ethyl iodide, benzyl iodide, and alkyl or aryl sulfonates such as methyl methanesulfonate and methyl paratoluenesulfonate Epoxy such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether It is possible to use kind and the like.

  In the present invention, the amount of the acid or quaternizing agent used for neutralization or quaternization of the tertiary amino group is used to express the excellent storage stability of the aqueous dispersion of the cationic urethane resin (a1). This is preferably in the range of 0.1 to 3 equivalents relative to 1 equivalent of the tertiary amino group, and more preferably in the range of 0.3 to 2.0 equivalents.

  The reaction between the compound (a2-1) having two epoxy groups in one molecule and the secondary amine (a2-2) is carried out by reacting the epoxy group of the compound (a2-1) with the secondary amine (a2). -2) reaction ratio with NH group [NH group / epoxy group] equivalent ratio is preferably 0.5 / 1 to 1.1 / 1, preferably 0.9 / 1 to 1/1. It is more preferable to carry out in the range.

  The reaction of the compound (a2-1) and the secondary amine (a2-2) can be performed under solvent-free conditions, but for the purpose of facilitating the reaction control or stirring load due to viscosity reduction. For the purpose of reducing or uniformly reacting, an organic solvent can be used.

  Such an organic solvent may be any organic solvent that does not inhibit the reaction. For example, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, acetates such as ethyl acetate, and hydrocarbons such as n-hexane and toluene. In addition, chlorinated hydrocarbons such as dichloromethane and amides such as dimethylformamide can be used.

  Among the organic solvents described above, when an organic solvent having a low boiling point is used, it is preferable to perform a pressure reaction in a closed system in order to prevent scattering due to volatilization.

  The compound (a2-1) having two epoxy groups in one molecule and the secondary amine (a2-2) may be supplied together in a reaction vessel and reacted, and an epoxy group is contained in one molecule. Either one of the two compounds (a2-1) and the secondary amine (a2-2) may be charged into a reaction vessel and the other may be dropped.

  Since the reaction between the compound (a2-1) having two epoxy groups in one molecule and the secondary amine (a2-2) has high reactivity, it usually does not require a catalyst. However, when the substituent of the secondary amine (a2-2), such as an aliphatic group, is large and the reaction with the compound (a2-1) is slowed by steric hindrance, phenol, acetic acid, water A proton donating substance typified by alcohols may be used as a catalyst.

The reaction temperature is preferably in the range of room temperature to 160 ° C, more preferably in the range of 60 to 120 ° C. The reaction time is not particularly limited, but is usually in the range of 30 minutes to 14 hours. The end point of the reaction can be confirmed by disappearance of the absorption peak near 842 cm ⁻¹ due to the epoxy group by infrared spectroscopy (IR method).

  The tertiary amino group-containing polyol (a2-3) is based on the total amount of the polyol (a2-4) used for the production of the cationic urethane resin (a1) from the viewpoint of imparting excellent storage stability. It is preferable to use in the range of 0.5 mass% to 10 mass%.

  As the polyol (a2-4) that can be used for producing the cationic urethane resin (a1), in addition to the tertiary amino group-containing polyol (a2-3), a urethane resin is generally used depending on the purpose and application. Other polyols utilized in the synthesis of can be used.

  Examples of the other polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neo. Pentyl glycol, 1,8-octanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 300 to 6,000), dipropylene glycol, tripropylene Relatively low molecular weight polyols such as glycol, bishydroxyethoxybenzene, bisphenol A, hydroquinone and their alkylene oxide adducts, polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, Li ester amide polyol, polythioether polyol, may also be used high molecular weight polyol such as polyolefin polyols such as polybutadiene.

  Examples of the polyester polyol include those obtained by an esterification reaction of a low molecular weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymers of these. Polymerized polyester or the like can be used.

  Examples of the polyether polyol include addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide using one or more compounds having two or more active hydrogen atoms such as ethylene glycol and diethylene glycol as an initiator. Can be used.

  Further, as the polycarbonate polyol, those obtained by reacting glycol such as 1,4-butanediol and 1,5-pentanediol with dimethyl carbonate, phosgene and the like can be used.

  Moreover, as polyisocyanate (a2-5) used when manufacturing the said cationic urethane resin (a1), aromatic diisocyanates, such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and hexamethylene diisocyanate, for example. , Lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, etc. The above can be used in combination. Among these, it is more preferable to use isophorone diisocyanate, dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate for forming a coating film having excellent corrosion resistance.

  Moreover, when manufacturing what has the said hydrolysable silyl group and silanol group as said cationic urethane resin (a1), with the said polyol (a2-4) and polyisocyanate (a2-5), the following general formula The compound represented by [IV] is reacted.

(In the formula [IV], R ⁸ represents a monovalent organic residue selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and an aralkyl group, R ⁹ represents a halogen atom, an alkoxyl group, an acyloxy group, a phenoxy group, (A functional group selected from the group consisting of an iminooxy group or an alkenyloxy group, n represents an integer of 0 to 2, and Y represents an organic residue containing at least one amino group.)

  Examples of the compound represented by the general formula [IV] include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-hydroxylethyl) aminopropyltrimethoxysilane, and γ- (2-aminoethyl). ) Aminopropyltriethoxysilane, γ- (2-hydroxylethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxycyaminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyl Methyldiethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldimethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldiethoxysilane or γ- (N, N-di-2-hydroxylethyl) aminopropyl Triethoxysilane, γ-Ami Nopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane or γ- (N-phenyl) aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxy Silane, γ-mercaptophenyltrimethoxysilane, and the like can be used, and γ-aminopropyltrialkoxysilane is preferably used for improving the corrosion resistance and heat discoloration of the coating film.

  The compound represented by the general formula [IV] is in the range of 0.1% by mass to 10% by mass with respect to the total amount of the polyol (a2-4) and the polyisocyanate (a2-5). It is preferable.

  The cationic urethane resin (a1) comprises a polyol (a2-4) containing a tertiary amino group-containing polyol (a2-4) and a polysiloxane in the absence of a solvent, in the presence of an organic solvent, or in the presence of a reactive diluent. Urethane obtained by producing a urethane resin by bringing isocyanate (a2-5) and, if necessary, the compound represented by the general formula [III] into a reaction vessel in a batch or divided and reacting them. It can be produced by neutralizing some or all of the tertiary amino groups in the resin with an acid and / or quaternizing with a quaternizing agent.

  In the reaction, the equivalent ratio [isocyanate group / hydroxyl group] of the hydroxyl group of the polyol (a2-4) containing the tertiary amino group-containing polyol (a2-4) and the isocyanate group of the polyisocyanate (a2-5) is It is preferable to carry out in the range of 0.9 / 1 to 1.1 / 1.

  Moreover, it is preferable to perform the said reaction in the temperature range of 20 to 120 degreeC, and it is more preferable to carry out in the temperature range of 30 to 100 degreeC.

  Examples of the organic solvent that can be used as the solvent when performing the reaction include ketones such as acetone, diethyl ketone, methyl ethyl ketone, and methyl isobutyl ketone; diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, Ethers such as tetrahydrofuran and dioxane; Acetic esters such as ethyl acetate, butyl acetate and propyl acetate; Nitriles such as acetonitrile; Carbonization of n-pentane, n-hexane, cyclohexane, n-heptane, benzene, toluene, xylene and the like Hydrogens; chlorinated hydrocarbons such as carbon tetrachloride, dichloromethane, chloroform, trichloroethane; amides such as dimethylformamide and N-methylpyrrolidone can be used. If necessary, the organic solvent is preferably removed during the reaction or after the reaction, for example, by a method such as heating under reduced pressure.

  Moreover, when performing the said reaction, it is preferable to use the vinyl monomer which can be used for manufacture of the said vinyl polymer (a2) as a reactive diluent which can be used for a solvent.

  When the cationic urethane resin (a1) is produced, a polyamine may be used as a chain extender for the purpose of designing a urethane resin having physical properties such as various mechanical properties and thermal properties.

  Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, Diamines containing one primary amino group and one secondary amino group such as N-methylaminopropylamine; polyamines such as diethylenetriamine, dipropylenetriamine and triethylenetetramine; hydrazine, N Hydrazines such as N′-dimethylhydrazine and 1,6-hexamethylenebishydrazine; Dihydrazides such as succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide; Semicarbazides such as 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazide methyl-3,5,5-trimethylcyclohexane can be used.

  The polyamine is preferably used in a range where the equivalent ratio of the amino group of the polyamine and the isocyanate group of the urethane resin is 1.9 or less (equivalent ratio), 0.5 to 1.5 (equivalent It is more preferable to use it in the range of the ratio.

  As a method for producing the aqueous dispersion using the cationic urethane resin (a1) obtained by the above method, for example, the cationic urethane resin (a1) and the aqueous medium (B) are mixed and stirred. Can be manufactured. Mixing of the cationic urethane resin (a1) and the aqueous medium (B) may be performed using a machine such as a homogenizer as necessary.

  The aqueous dispersion of the cationic urethane resin (a1) obtained by the above method preferably contains 10% to 65% by mass of the cationic urethane resin (a1), and contains 15% to 35% by mass. It is more preferable.

  Next, the step (X) of producing a vinyl polymer (a2) by polymerizing a vinyl monomer in the aqueous dispersion of the cationic urethane resin (a1) obtained in the step (W) will be described.

  As the vinyl polymer (a2) constituting the composite resin particles (A) used in the present invention, those obtained by radical polymerization of various vinyl monomers in the presence of a polymerization initiator can be used. .

  As the vinyl monomer, for example, an acid group-containing vinyl monomer, a vinyl monomer having a silicon atom-containing group, or the like can be used.

  Among these, the use of an acid group-containing vinyl monomer is preferable for forming a tough coating film having excellent film forming properties.

  As the acid group-containing vinyl monomer, for example, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid can be used. Among these, the use of methacrylic acid is preferable in the case where (meth) acrylic acid ester is used as the other vinyl monomer described later, and it is easy to copolymerize and exhibits excellent water resistance.

  Examples of the vinyl monomer having a silicon atom-containing group include 3- (meth) acryloyloxyethyl-trimethoxysilane, 3- (meth) acryloyloxyethyl-triethoxysilane, and 3- (meth) acryloyl. 3- (meth) acryloyloxyalkyl-trialkoxysilane such as oxypropyl-trimethoxysilane, 3- (meth) acryloyloxypropyl-triethoxysilane; 3- (meth) acryloyloxyethyl-methyldimethoxysilane, 3- ( 3- (meth) acryloyloxyalkyl-alkyl such as (meth) acryloyloxyethyl-methyldiethoxysilane, 3- (meth) acryloyloxypropyl-methyldimethoxysilane, 3- (meth) acryloyloxypropyl-methyldiethoxysilane Alkoxysilanes; it can be used vinyl methyl dimethoxy silane, vinyl alkyl dialkoxy silane such as vinyl ethyl diethoxy silane; vinyltrimethoxysilane, vinyl trialkoxysilanes such as vinyl triethoxysilane. Among them, it is preferable to use 3- (meth) acryloyloxypropyl-trialkoxysilane in order to achieve both substrate adhesion and coating film toughness.

  The acid group-containing vinyl monomer is preferably used in the range of 0.1% by mass to 10% by mass with respect to the total amount of the vinyl monomer used for the production of the vinyl polymer (a2).

  In the production of the vinyl polymer (a2), in addition to the acid group-containing vinyl monomer and the like, other vinyl monomers can be used in combination as required.

  Examples of the other vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl. (Meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopenta (Meth) acrylic esters such as nyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-penta Fluoro Fluorine-containing vinyl monomers such as propyl (meth) acrylate and perfluorocyclohexyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, etc. Vinyl ethers; unsaturated carboxylic acid nitriles such as (meth) acrylonitrile; vinyl compounds having an aromatic ring such as styrene, α-methylstyrene, divinylstyrene; isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, fluorine Epoxy group-containing polymerizable monomers such as vinylidene chloride and N-vinylpyrrolidone, glycidyl (meth) acrylate, and allyl glycidyl ether; 2-hydroxyethyl (meth) acrylate Hydroxyl group-containing polymerizable monomers such as 2-hydroxypropyl (meth) acrylate and polyethylene glycol mono (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate Tertiary amino group-containing polymerizable monomers such as N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate acrylate; Amide group-containing polymerizable monomers such as (meth) acrylamide, N-monoalkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide; N-methylol (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide N-butoxymethyl (meta Methylolamide groups such as acrylamide and N-isobutoxymethyl (meth) acrylamide and polymerizable monomers containing alkoxylates thereof; polymerizable monomers containing aziridinyl groups such as 2-aziridinylethyl (meth) acrylate; ) Isocyanate groups and / or blocked isocyanate group-containing polymerizable monomers such as phenol adducts of acryloyl isocyanate and (meth) acryloyl isocyanate ethyl; 2-isopropenyl-2-oxazoline, 2-vinyl-2 -Oxazoline group-containing polymerizable monomers such as oxazoline and 2-oxazodinylethyl (meth) acrylate; Cyclopentenyl group-containing polymerizable monomers such as dicyclopentenyl (meth) acrylate; Acrolein, diacetone (meth) Carbonyl group-containing heavy such as acrylamide Sex monomer; there may be mentioned an acetoacetyl group-containing polymerizable monomers such as acetoacetoxyethyl (meth) acrylate, can be used one kind of them or a mixture of two or more.

  Among these, the other vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2 -It is preferable to use (meth) acrylic acid ester monomers such as ethylhexyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate, and they are used as vinyl polymer (a2). It is preferable to use it in the range of 50% by mass to 99% by mass with respect to the total amount of the vinyl monomer used for the production of the coating film, because it is excellent in balance of performance such as water resistance of the obtained coating film.

  In addition, the polymerization of the vinyl polymer (a2) is performed by dividing the vinyl monomer and the polymerization initiator separately in the aqueous dispersion of the cationic urethane resin (a1) or a mixture thereof in a lump. And the vinyl monomer is polymerized in the cationic urethane resin (a1) particles dispersed in an aqueous medium.

  At this time, the vinyl monomer is preferably supplied alone in the aqueous dispersion of the cationic urethane resin (a1) without using a surfactant. As a result, the vinyl monomer cannot be stably present in the aqueous medium (B) and polymerizes inside the already existing cationic urethane resin (a1) particles. As a result, composite resin particles (A) having the cationic urethane resin (a1) in the shell layer and the vinyl polymer (a2) in the core layer can be produced.

  Examples of the polymerization initiator that can be used in producing the vinyl polymer (a2) include radical polymerization initiators such as persulfates, organic peroxides, and hydrogen peroxide, and 4,4′-azobis ( An azo initiator such as 4-cyanovaleric acid) or 2,2′-azobis (2-amidinopropane) dihydrochloride can be used. The radical polymerization initiator may be used as a redox polymerization initiator in combination with a reducing agent described later.

  Examples of the persulfates that are representative of the polymerization initiator include potassium persulfate, sodium persulfate, and ammonium persulfate. Specific examples of organic peroxides include, for example, peroxidation. Diacyl peroxides such as benzoyl, lauroyl peroxide, decanoyl peroxide, dialkyl peroxides such as t-butylcumyl peroxide, dicumyl peroxide, t-butylperoxylaurate, t-butylperoxybenzoate, etc. Peroxyesters, cumene hydroperoxide, paramentane hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, and the like can be used.

  Examples of the reducing agent include ascorbic acid and salts thereof, erythorbic acid and salts thereof, tartaric acid and salts thereof, citric acid and salts thereof, metal salts of formaldehyde sulfoxylate, sodium thiosulfate, sodium bisulfite, and the like. Can be used.

  The polymerization initiator may be used in an amount that allows the polymerization to proceed smoothly, but is preferably less in terms of maintaining excellent water resistance of the resulting coating film, and production of the vinyl polymer (a2) It is preferable to set it as 0.01 mass%-0.5 mass% with respect to the whole quantity of the vinyl monomer used for. Moreover, when using the said polymerization initiator together with the said reducing agent, it is preferable that the usage-amount of those total amounts is also in the above-mentioned range.

  Moreover, as an aqueous medium (B) used by this invention, the organic solvent mixed with water and water, and these mixtures are mentioned. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and load on the environment, water alone or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.

  In the present invention, when the aqueous medium (B) is used as a solvent in the process of producing the composite resin particles (A), the aqueous medium (B) can be continuously used.

  The aqueous medium (B) suppresses a sudden increase in viscosity during production, and improves the productivity of the aqueous resin composition, ease of coating, drying properties, and the like. The nonvolatile content is preferably 20% by mass to 70% by mass with respect to the total amount of the aqueous resin composition, and more preferably in the range of 25% by mass to 60% by mass.

  Various additives can be used in combination with the aqueous resin composition of the present invention obtained by the above method, if necessary. Especially, it is preferable to use a curing catalyst together from a viewpoint of forming the crosslinked coating film excellent in solvent resistance.

  Examples of the curing catalyst include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, tetraisopropyl titanate, tetra-n-butyl titanate, tin octylate, lead octylate, cobalt octylate, and zinc octylate. Calcium octylate, zinc naphthenate, cobalt naphthenate, di-n-butyltin diacetate, di-n-butyltin dioctoate, di-n-butyltin dilaurate, di-n-butyltin maleate, p-toluenesulfone Acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, monoalkyl phosphorous acid, dialkyl phosphorous acid and the like can be used.

  Further, the aqueous resin composition of the present invention may contain an emulsifier, a dispersion stabilizer and a leveling agent as necessary, but from the viewpoint of suppressing a decrease in water resistance of the crosslinked coating film, it may not contain as much as possible. Preferably, it is 0.5% by mass or less based on the solid content of the aqueous resin composition.

  Thus, since the aqueous resin composition of the present invention can form a coating film excellent in heat resistance, water resistance, solvent resistance, etc., it can provide surface protection for various base materials and impart design properties to various base materials. It can be used for the coating agent used for the purpose.

  Examples of the base material include various plastics and films thereof, metal, glass, paper, and wood. In particular, when the coating agent of the present invention is used for various plastic substrates, a coating film having excellent solvent resistance and water resistance can be formed even in a drying process at a relatively low temperature, and the coating film from the plastic substrate can be formed. Peeling can be prevented.

  As a plastic substrate, acrylonitrile-butadiene-styrene resin (ABS resin), polycarbonate resin (PC resin) are generally used as plastic molded products such as mobile phones, home appliances, automotive interior and exterior materials, and office automation equipment. ), ABS / PC resin, polystyrene resin (PS resin), polymethylmethacrylate resin (PMMA resin), acrylic resin, polypropylene resin, polyethylene resin, etc., and plastic film base materials include polyethylene terephthalate film, polyester film, A polyethylene film, a polypropylene film, a TAC (triacetyl cellulose) film, a polycarbonate film, a polyvinyl chloride film and the like can be used.

  Moreover, since the coating agent of the present invention can form a densely formed crosslinked coating film that can suppress corrosion of the metal material itself, it is preferably used for a coating material for a metal substrate, that is, a steel sheet surface treatment agent. Can do.

  Examples of the metal substrate include galvanized steel sheets used for applications such as automobiles, home appliances, and building materials, plated steel sheets such as aluminum-zinc alloy steel sheets, aluminum plates, aluminum alloy plates, electromagnetic steel plates, copper plates, stainless steel plates, etc. Can be used.

  The coating agent of the present invention exhibits extremely excellent solvent resistance against organic solvents such as methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, and toluene even when the cross-linked coating film has a thickness of about 5 μm. It is possible. Moreover, even if the coating agent of this invention is a film thickness of about 1 micrometer, it can form the coating film excellent in chemical resistance including acid resistance, alkali resistance, etc.

  The coating agent of the present invention can be formed on a substrate by coating, drying and curing.

  Examples of the coating method for the coating agent include a spray method, a curtain coater method, a flow coater method, a roll coater method, a brush coating method, and a dipping method.

  The drying may be natural drying at normal temperature, but may be heat-dried. Heat drying is usually preferably performed at 40 ° C. to 250 ° C. for about 1 to 600 seconds.

  In addition, when a base material is a thing which is easy to deform | transform with heat like a plastic base material etc., it is preferable to adjust the drying temperature of a coating film to about 80 degrees C or less. Here, the coating film obtained by drying the conventional coating agent at a low temperature of 80 ° C. or lower may not have sufficient solvent resistance. On the other hand, the coating agent of the present invention proceeds at a low temperature (normal temperature) after drying, even if the coating agent of the present invention is dried at a low temperature of 80 ° C. or less for a short time of about several seconds. A crosslinked coating film exhibiting excellent solvent resistance, water resistance and chemical resistance can be formed.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples.

[Synthesis Example 1] Synthesis of Tertiary Amino Group-Containing Polyol (E) -I A polypropylene flask-diglycidyl ether (epoxy equivalent 201 g / Equivalent) After charging 590 parts by mass, the flask was purged with nitrogen. Next, after heating using an oil bath until the temperature in the flask reaches 70 ° C., 380 parts by mass of di-n-butylamine is added dropwise over 30 minutes using a dropping device. The reaction was allowed for 10 hours. After completion of the reaction, using an infrared spectrophotometer (FT / IR-460Plus, manufactured by JASCO Corporation), it is confirmed that the absorption peak near 842 cm ⁻¹ due to the epoxy group of the reaction product has disappeared. A tertiary amino group-containing polyol (E) -I (amine equivalent 339 g / equivalent, hydroxyl equivalent 339 g / equivalent) was prepared.

[Synthesis Example 2] Synthesis of tertiary amino group-containing polyol (E) -II Polyethylene glycol-diglycidyl ether (epoxy equivalent 185 g / equivalent) 543 instead of polypropylene glycol-diglycidyl ether (epoxy equivalent 201 g / equivalent) A tertiary amino group-containing polyol (E) -II (amine equivalent 315 g / equivalent, hydroxyl equivalent 315 g / equivalent) was prepared in the same manner as in Synthesis Example 1, except that parts by mass were used.

[Example 1]
Polycarbonate obtained by reacting “Nipporan 981” [manufactured by Nippon Polyurethane Industry Co., Ltd., 1,6-hexanediol and dimethyl carbonate, in a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device. Polyol, hydroxyl equivalent 501 g / equivalent. 120 parts by mass, 342 parts by mass of a polyester polyol (hydroxyl equivalent 951 g / equivalent) obtained by reacting neopentyl glycol, 1,4-butanediol, terephthalic acid and adipic acid, and adding 0 degree of vacuum Dehydration was performed at 120 ° C. to 130 ° C. at 0.095 MPa.

  After dehydration, the mixture was cooled to 70 ° C., 316 parts by mass of ethyl acetate was added, and the mixture was sufficiently stirred and mixed while cooling to 50 ° C. After stirring and mixing, 236 parts by mass of 4,4'-dicyclohexylmethane diisocyanate (4,4-H-MDI) and 0.2 part by mass of stannous octylate were added and reacted at 70 ° C for 2 hours.

  After completion of the reaction, 41 parts by mass of the tertiary amino group-containing polyol (E) -I obtained in Synthesis Example 1 was added and reacted for 4 hours, then cooled to 55 ° C., 384 parts by mass of ethyl acetate, N— 38 parts by mass of methyl-2-pyrrolidone was added to prepare a urethane prepolymer solution having a terminal isocyanate group. Next, 24 parts by mass of hydrazine hydrate was added to the urethane prepolymer solution, and a chain extension reaction was performed for 1 hour.

  Subsequently, 12 mass parts of 89 mass% phosphoric acid aqueous solution was added, and it hold | maintained at 55 degreeC for 1 hour, Then, it cooled to 40 degreeC and the water dispersion was prepared by adding 2844 mass parts of ion-exchange water. This aqueous dispersion was distilled under reduced pressure to prepare a cationic urethane resin aqueous dispersion (I) having a nonvolatile content of 25% by mass and a pH of 4.0. The pH is a value measured in a 25 ° C. environment using a pH meter (manufactured by Horiba, Ltd., M-12). Hereinafter, the pH was measured by the same method.

  Next, 358 parts by mass of ion-exchanged water was added to 900 parts by mass of the cationic urethane resin aqueous dispersion (I) obtained above, and the mixture was heated to 80 ° C. while blowing nitrogen gas. Under stirring, 146 parts by mass of methyl methacrylate and n -A vinyl monomer mixture containing 79 parts by mass of butyl acrylate, and 19 parts by mass of a 2,2'-azobis (2-methylpropionamidine) dihydrochloride aqueous solution (concentration: 2.5% by mass) as a polymerization initiator; Was dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C., and polymerized. After completion of dropping, the mixture was stirred at the temperature for 60 minutes, and then the vinyl resin formed by polymerizing the vinyl monomer mixture was inherent in the cationic urethane resin particles by adjusting the non-volatile content with an aqueous medium. An aqueous resin composition (I-1) comprising an aqueous dispersion of a urethane-vinyl composite resin and having a nonvolatile content of 30% by mass and a pH of 4.0 was obtained.

[Example 2]
Instead of a vinyl monomer mixture containing 146 parts by weight of methyl methacrylate and 79 parts by weight of n-butyl acrylate, a vinyl monomer mixture containing 180 parts by weight of methyl methacrylate and 45 parts by weight of n-butyl acrylate should be used. Except for the above, in the same manner as in Example 1, the vinyl resin formed by polymerizing the vinyl monomer mixture is composed of an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles. An aqueous resin composition (I-2) having a nonvolatile content of 30% by mass and a pH of 4.0 was obtained.

Example 3
Instead of a vinyl monomer mixture containing 146 parts by weight of methyl methacrylate and 79 parts by weight of n-butyl acrylate, 146 parts by weight of methyl methacrylate, 77 parts by weight of n-butyl acrylate and 3-methacryloyloxypropyl-trialkoxysilane 2 Except for using a vinyl monomer mixture containing parts by mass, the vinyl resin formed by polymerizing the vinyl monomer mixture in the same manner as in Example 1 is contained in the cationic urethane resin particles. An aqueous resin composition (I-3) comprising an aqueous dispersion of a urethane-vinyl composite resin having a nonvolatile content of 30% by mass and a pH of 4.0 was obtained.

Example 4
Except for using 900 parts by mass of the cationic urethane resin aqueous dispersion (I) 900 parts by weight of the cationic urethane resin aqueous dispersion (II) to be described later, the vinyl resin is obtained in the same manner as in Example 1. The vinyl resin formed by polymerizing the monomer mixture is composed of an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles. The nonvolatile content is 30% by mass and the pH is 4.0. An aqueous resin composition (I-4) was obtained.

  The cationic urethane resin aqueous dispersion (II) could be produced by the following method.

  Polycarbonate obtained by reacting “Nipporan 981” [manufactured by Nippon Polyurethane Industry Co., Ltd., 1,6-hexanediol and dimethyl carbonate, in a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device. Polyol, hydroxyl equivalent 501 g / equivalent. 120 parts by mass, 342 parts by mass of a polyester polyol (hydroxyl equivalent 951 g / equivalent) obtained by reacting neopentyl glycol, 1,4-butanediol, terephthalic acid and adipic acid, and adding 0 degree of vacuum Dehydration was performed at 120 ° C. to 130 ° C. at 0.095 MPa.

  After dehydration, the mixture was cooled to 70 ° C., 316 parts by mass of ethyl acetate was added, and the mixture was sufficiently stirred and mixed while cooling to 50 ° C. After stirring and mixing, 236 parts by mass of 4,4'-dicyclohexylmethane diisocyanate (4,4-H-MDI) and 0.2 part by mass of stannous octylate were added and reacted at 70 ° C for 2 hours.

  After completion of the reaction, 41 parts by mass of the tertiary amino group-containing polyol (E) -I obtained in Synthesis Example 1 was added, reacted for 4 hours, cooled to 55 ° C., and “aminosilane A1100” [Nihon Unicar Co., Ltd. (Company, γ-aminopropyltriethoxysilane) 24 parts by mass was added and allowed to react for 1 hour, and then 384 parts by mass of ethyl acetate and 38 parts by mass of N-methyl-2-pyrrolidone were added. A urethane prepolymer solution having a radical group was prepared. Next, 24 parts by mass of hydrazine hydrate was added to the urethane prepolymer solution, and a chain extension reaction was performed for 1 hour.

  Subsequently, 12 mass parts of 89 mass% phosphoric acid aqueous solution was added, and it hold | maintained at 55 degreeC for 1 hour, Then, it cooled to 40 degreeC and the water dispersion was prepared by adding 2844 mass parts of ion-exchange water. This aqueous dispersion was distilled under reduced pressure to prepare a cationic urethane resin aqueous dispersion (II) having a nonvolatile content of 25% by mass and a pH of 3.9.

Example 5
Instead of 900 parts by weight of the cationic urethane resin aqueous dispersion (I), 900 parts by weight of the cationic urethane resin aqueous dispersion (II) is used, and 146 parts by weight of methyl methacrylate and 79 parts by weight of n-butyl acrylate are used. A method similar to Example 1 except that a vinyl monomer mixture containing 146 parts by mass of methyl methacrylate, 74 parts by mass of n-butyl acrylate, and 5 parts by mass of methacrylic acid is used instead of the vinyl monomer mixture containing The vinyl resin formed by polymerizing the vinyl monomer mixture is composed of an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles, the non-volatile content is 30% by mass, and the pH is The aqueous resin composition (I-5) which is 3.8 was obtained.

Example 6
Vinyl formed by polymerizing the vinyl monomer mixture in the same manner as in Example 5 except that the amount of the cationic urethane resin aqueous dispersion (II) used was changed from 900 parts by weight to 3600 parts by weight. An aqueous resin composition (I-6) having a nonvolatile content of 27% by mass and a pH of 3.8, wherein the resin is an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles Obtained.

Example 7
Instead of a vinyl monomer mixture containing 146 parts by weight of methyl methacrylate and 79 parts by weight of n-butyl acrylate, a vinyl monomer containing 45 parts by weight of methyl methacrylate, 175 parts by weight of n-butyl acrylate and 5 parts by weight of methacrylic acid Except for using a mixture, the vinyl resin formed by polymerizing the vinyl monomer mixture in the same manner as in Example 1 was a water-based urethane-vinyl composite resin contained in the cationic urethane resin particles. An aqueous resin composition (I-7) comprising a dispersion and having a nonvolatile content of 30% by mass and a pH of 3.7 was obtained.

Example 8
Polycarbonate obtained by reacting “Nipporan 981” [manufactured by Nippon Polyurethane Industry Co., Ltd., 1,6-hexanediol and dimethyl carbonate, in a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device. Polyol, hydroxyl equivalent 501 g / equivalent. 120 parts by mass, 342 parts by mass of a polyester polyol (hydroxyl equivalent 951 g / equivalent) obtained by reacting neopentyl glycol, 1,4-butanediol, terephthalic acid and adipic acid, and adding 0 degree of vacuum Dehydration was performed at 120 ° C. to 130 ° C. at 0.095 MPa.

  After dehydration, the mixture was cooled to 70 ° C., 316 parts by mass of ethyl acetate was added, and the mixture was sufficiently stirred and mixed while cooling to 50 ° C. After stirring and mixing, 236 parts by mass of 4,4'-dicyclohexylmethane diisocyanate (4,4-H-MDI) and 0.2 part by mass of stannous octylate were added and reacted at 70 ° C for 2 hours.

  After completion of the reaction, 38 parts by mass of the tertiary amino group-containing polyol (E) -II obtained in Synthesis Example 1 was added, reacted for 4 hours, cooled to 55 ° C., and “aminosilane A1100” [Nihon Unicar Co., Ltd. (Company, γ-aminopropyltriethoxysilane) 24 parts by mass was added and allowed to react for 1 hour, and then 384 parts by mass of ethyl acetate and 38 parts by mass of N-methyl-2-pyrrolidone were added. A urethane prepolymer solution having a radical group was prepared. Next, 24 parts by mass of hydrazine hydrate was added to the urethane prepolymer solution, and a chain extension reaction was performed for 1 hour.

  Subsequently, 12 mass parts of 89 mass% phosphoric acid aqueous solution was added, and it hold | maintained at 55 degreeC for 1 hour, Then, it cooled to 40 degreeC and the water dispersion was prepared by adding 2844 mass parts of ion-exchange water. This aqueous dispersion was distilled under reduced pressure to prepare a cationic urethane resin aqueous dispersion (III) having a nonvolatile content of 25% by mass and a pH of 4.0.

  Next, 358 parts by mass of ion-exchanged water was added to 900 parts by mass of the cationic urethane resin aqueous dispersion (III) obtained above, and heated to 80 ° C. while blowing nitrogen gas. Under stirring, 146 parts by mass of methyl methacrylate and n -A vinyl monomer mixture containing 74 parts by mass of butyl acrylate and 5 parts by mass of methacrylic acid, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride aqueous solution (concentration: 2.5 masses) as a polymerization initiator %) 19 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization. After completion of dropping, the mixture was stirred at the temperature for 60 minutes, and then the vinyl resin formed by polymerizing the vinyl monomer mixture was inherent in the cationic urethane resin particles by adjusting the non-volatile content with an aqueous medium. An aqueous resin composition (I-8) comprising an aqueous dispersion of a urethane-vinyl composite resin and having a nonvolatile content of 30% by mass and a pH of 3.8 was obtained.

Example 9
Polycarbonate obtained by reacting “Nipporan 981” [manufactured by Nippon Polyurethane Industry Co., Ltd., 1,6-hexanediol and dimethyl carbonate, in a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device. Polyol, hydroxyl equivalent 501 g / equivalent. 120 parts by mass, 342 parts by mass of a polyester polyol (hydroxyl equivalent 951 g / equivalent) obtained by reacting neopentyl glycol, 1,4-butanediol, terephthalic acid and adipic acid, and adding 0 degree of vacuum Dehydration was performed at 120 ° C. to 130 ° C. at 0.095 MPa.

  After dehydration, the mixture was cooled to 70 ° C., 316 parts by mass of ethyl acetate was added, and the mixture was sufficiently stirred and mixed while cooling to 50 ° C. After stirring and mixing, 157 parts by mass of 4,4′-dicyclohexylmethane diisocyanate (4,4-H-MDI), 52 parts by mass of tolylene diisocyanate and 0.2 parts by mass of stannous octylate were added, and at 70 ° C. The reaction was performed for 2 hours.

  After completion of the reaction, 49 parts by mass of the tertiary amino group-containing polyol (E) -II obtained in Synthesis Example 1 was added, reacted for 4 hours, cooled to 55 ° C., and “aminosilane A1100” [Nihon Unicar Co., Ltd. [Company, γ-aminopropyltriethoxysilane] 35 parts by mass was added and allowed to react for 1 hour, and then 384 parts by mass of ethyl acetate and 38 parts by mass of N-methyl-2-pyrrolidone were added. A urethane prepolymer solution having a radical group was prepared. Next, 20 parts by mass of hydrazine hydrate was added to the urethane prepolymer solution, and a chain extension reaction was performed for 1 hour.

  Subsequently, 18 mass parts of 89 mass% phosphoric acid aqueous solution was added, and it hold | maintained at 55 degreeC for 1 hour, Then, it cooled to 40 degreeC and the water dispersion was prepared by adding 2844 mass parts of ion-exchange water. This aqueous dispersion was distilled under reduced pressure to prepare a cationic urethane resin aqueous dispersion (IV) having a nonvolatile content of 25% by mass and a pH of 4.0.

  Next, 358 parts by mass of ion-exchanged water was added to 900 parts by mass of the cationic urethane resin aqueous dispersion (IV) obtained above, and heated to 80 ° C. while blowing nitrogen gas. Under stirring, 146 parts by mass of methyl methacrylate and n -A vinyl monomer mixture containing 74 parts by mass of butyl acrylate and 5 parts by mass of methacrylic acid, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride aqueous solution (concentration: 2.5 masses) as a polymerization initiator %) 19 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization. After completion of dropping, the mixture was stirred at the temperature for 60 minutes, and then the vinyl resin formed by polymerizing the vinyl monomer mixture was inherent in the cationic urethane resin particles by adjusting the non-volatile content with an aqueous medium. An aqueous resin composition (I-9) comprising an aqueous dispersion of a urethane-vinyl composite resin and having a nonvolatile content of 30% by mass and a pH of 3.8 was obtained.

Example 10
Instead of 900 parts by mass of the cationic urethane resin aqueous dispersion (I), 900 parts by mass of the cationic urethane resin aqueous dispersion (V) described later is used, and 146 parts by mass of methyl methacrylate and 79 parts by mass of n-butyl acrylate. Example 4 with the exception of using a vinyl monomer mixture containing 146 parts by weight of methyl methacrylate, 74 parts by weight of n-butyl acrylate, and 5 parts by weight of methacrylic acid instead of the vinyl monomer mixture containing 5 parts by weight. In the same manner, the vinyl resin formed by polymerizing the vinyl monomer mixture is composed of an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles, and the nonvolatile content is 30% by mass. An aqueous resin composition (I-10) having a pH of 3.8 was obtained.

[Comparative Example 1]
The vinyl monomer mixture was polymerized in the same manner as in Example 1 except that 14 parts by mass of N-methyldiethanolamine was used instead of 41 parts by mass of the tertiary amino group-containing polyol (E) -I. An aqueous resin composition having a non-volatile content of 30% by mass and a pH of 3.9, wherein the vinyl resin formed is an aqueous dispersion of urethane-vinyl composite resin contained in the cationic urethane resin particles. I'-1) was obtained.

[Comparative Example 2]
To a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a dropping device, add 508 parts by mass of ion exchange water and 1 part by mass of hexadecyltrimethylammonium chloride, and heat to 80 ° C. while blowing nitrogen gas. Under stirring, a vinyl monomer mixture containing 146 parts by mass of methyl methacrylate and 79 parts by mass of n-butyl acrylate, and 2,2′-azobis (2-methylpropionamidine) dihydrochloride aqueous solution (concentration: 2.5 mass%) 19 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C., and polymerized. After completion of dropping, the mixture is stirred at the above temperature for 60 minutes, and then the non-volatile content is adjusted with an aqueous medium, whereby the vinyl monomer mixture having a non-volatile content of 30% by mass and a pH of 6.8 is polymerized. An aqueous vinyl resin dispersion (III) was obtained. Subsequently, the cationic urethane resin aqueous dispersion and the vinyl resin aqueous dispersion were mixed by adding 900 parts by mass of the cationic urethane resin aqueous dispersion (I) to the vinyl resin aqueous dispersion (III) obtained in the previous period. An aqueous resin composition (I′-2) having a nonvolatile content of 27 mass% and a pH of 5.2 was obtained.

[Method for evaluating storage stability]
In a 140 mL glass sample bottle, 100 mL of the aqueous resin composition obtained in Examples and Comparative Examples was put and sealed, and left in a 40 ° C. environment for 3 months. The aqueous resin composition after standing was visually checked for the presence of precipitates and aggregates. When no precipitate or aggregate was observed, the evaluation was “◯”, and when precipitation or aggregate was observed, the evaluation was “X”.

[Water resistance (warm water resistance)]
A polypropylene film having an outer frame with a height of 1 mm was attached to an A4 size glass plate, and the aqueous resin compositions obtained in Examples and Comparative Examples were poured onto the polypropylene film so as to be 6 g / 100 cm ² . By drying at 25 ° C. for 1 day, a coating film having a thickness of about 150 μm was produced. Next, the coating film was peeled from the polypropylene film and cut into a length of 3.0 cm and a width of 3.0 cm to obtain a test piece. After measuring the mass [V] of the test piece, the test piece was immersed in warm water at 40 ° C. for 24 hours, and the dimensions of both sides, vertical [X] cm and horizontal [Y] cm were measured. The area swelling of the test piece based on the dimensions [X] and [Y] of the test piece before and after immersion and the formula {([X] × [Y]) / (3.0 × 3.0) -1} × 100 The rate was calculated.

  An area swelling ratio of less than 5% was evaluated as “◎”, 5% or more but less than 10% as “◯”, 10% or more but less than 30% as “Δ”, and 30% or more as “x”.

  Moreover, the test piece after immersion was dried for 1 hour on 108 degreeC conditions, and mass [Z] of this test piece was measured. The dissolution rate of the test piece was calculated based on the mass [V] and [Z] of the test piece before and after immersion and the formula (1-mass [Z] / mass [V]) × 100. The dissolution rate is less than 0.5% by mass “◎”, the dissolution rate is 0.5% by mass to less than 1% by mass “◯”, 1% by mass to less than 5% by mass “Δ”, and 5% by mass or more. Evaluated as “x”.

[Adhesion to metal substrate]
Using a film applicator, each of the aluminum plate and the galvanized steel plate was coated with the aqueous resin composition obtained in the example immediately after production and the comparative example so that the coating amount was 0.4 g / 100 cm ² , and 100 ° C. Two types of test pieces were prepared by drying for 1 minute. Subsequently, 100 1 mm square grids were cut into the coating film formed on the test piece, and a cellophane adhesive tape was stuck on the grids formed. Next, the adhesive tape was peeled off in the 180-degree direction, and the adhesion to the metal substrate was evaluated based on the number of grids made of the coating film remaining on the metal substrate. Adhesiveness is “◎” when 100 of the 100 grids remain on the metal substrate, “◯” when 90 or more and less than 100 remain on the metal substrate, 70 The case where not less than 90 pieces remained on the metal substrate was evaluated as “Δ”, and the case where less than 70 pieces remained on the metal substrate was evaluated as “x”.

[Corrosion resistance]
Using the film applicator, each of the aqueous resin compositions obtained in Examples and Comparative Examples immediately after production is applied to a galvanized steel sheet so as to have an application amount of 0.4 g / 100 cm ² and dried at 100 ° C. for 1 minute. Thus, a test piece was prepared.

  Next, in accordance with the salt spray test method described in JIS Z2371, the test piece was sprayed with a 5% NaCl aqueous solution at an atmospheric temperature of 35 ° C., and the white rust occurrence rate after 120 hours was measured. And evaluated. In addition, the uncoated part (end surface part, back surface part) of the aqueous resin composition was tape-sealed. "◎" indicates that no white rust has occurred, and "○" indicates that the area where white rust is generated is less than 5% of the total area sprayed with salt water. However, it was evaluated as “Δ” when the area was 5% or more and less than 20% of the entire coated area, and “X” when the area where white rust was generated was 20% or larger of the entire coated area.

[Alkali resistance]
On the surface of the galvanized steel sheet, the aqueous resin compositions obtained in the examples and comparative examples immediately after production were applied using a film applicator so that the coating amount was 0.4 g / 100 cm ^2. The test piece was produced by drying for minutes.

  0.5 mL of 5 mass% sodium hydroxide aqueous solution was dripped on the coating film surface of the said test piece, and it was left to stand for 15 minutes.

  After standing, the appearance of the coating film surface of the test piece was visually observed, and the alkali resistance of the coating film was evaluated according to the following criteria. “◎” indicates that there was no change in appearance on the surface of the coating film, and indicates that the coating film was blackened or dissolved within a range of less than 10% of the area of the coating film in contact with the aqueous sodium hydroxide solution. “◯” indicates a change in the black color or dissolution of the coating film within a range of 10% or more and less than 30%, and “△” indicates a black change or dissolution of the coating film in a range of 30% or more. Was evaluated as “×”.

[Heat-resistant discoloration]
A polypropylene film having an outer frame with a height of 1 mm is attached to an A4 size glass plate, and the cationic urethane resin compositions obtained in Examples and Comparative Examples are 6 g / 100 cm ² on the polypropylene film. And dried at 25 ° C. for 1 day to prepare a coating film having a thickness of about 150 μm.

  The coating film obtained by heat-treating the coating film at 108 ° C. for 2 hours and then peeling from the polypropylene film was used as a test film.

  The test film obtained above was subjected to a heat discoloration test in which it was left for 30 minutes at a temperature of 200 ° C., and the degree of discoloration of the film after the test was measured using a spectrocolorimeter (CM-3500d) manufactured by Konica Minolta. ) Based on the following criteria. The film for test having a Δb value of less than 5 is “◎”, the film having a Δb value of 5 or more and less than 10 is “◯”, and the film having a Δb value of 10 or more and less than 15 is “Δ”. The Δb value of 15 or more was evaluated as “x”.

Claims (5)

Composite resin particles (A) composed of a cationic urethane resin (a1) having a structure represented by the following general formula [I] and a vinyl polymer (a2) are dispersed in an aqueous medium (B). An aqueous resin composition characterized by that.

[In the formula [I], R ¹ represents an alkylene group having an aliphatic or aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ² and R ³ are independently of each other. An alkyl group having an aliphatic or aliphatic cyclic structure, R ⁴ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ] 2. The aqueous resin composition according to claim 1, wherein the composite resin particles (A) are a part of or all of the vinyl polymer (a2) in the cationic urethane resin (a1) particles. The aqueous resin composition according to claim 1, wherein the cationic urethane resin (a1) has a structural unit represented by the following general formula [II].

(In the formula [II], R ⁵ is a monovalent organic group such as an alkyl group, aryl group or aralkyl group, and R ⁶ is a halogen atom, alkoxy group, acyloxy group, phenoxy group, aryloxy group, mercapto group, amino group. A group, an amide group, an aminooxy group, an iminooxy group or an alkenyloxy group, and x is an integer of 0 to 2.) The aqueous resin composition according to claim 1, wherein the vinyl polymer (a2) has an acid group or a silicon atom-containing group. The steel plate surface treating agent containing the aqueous resin composition of any one of Claims 1-4.