JP2022168034A - Aqueous coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating composition capable of forming a coating film excellent in adhesion to a polyolefin substrate, an ABS substrate and a PC substrate and having water-resistant adhesion property.

SOLUTION: An aqueous coating composition comprises an olefinic resin (A), and a hydroxyl group-containing resin (B) (except for the olefinic resin (A)) in the form of dispersion, wherein the hydroxyl group-containing resin (B) is at least one kind of resin selected from the group consisting of a urethane resin (B1) having a hydroxyl group, a (meth) acrylic urethane composite resin (B2) having a hydroxyl group and a (meth) acrylic resin (B3) having a hydroxyl group, and wherein the hydroxyl group-containing resin (B) has a hydroxyl value of 0.1 to 49 mgKOH/g.

SELECTED DRAWING: None

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to waterborne coating compositions.

Polyolefins such as polypropylene and copolymers of propylene and other α-olefins are inexpensive and have excellent mechanical properties, heat resistance, chemical resistance, water resistance, etc., so they are used in a wide range of fields. It is However, in the case of coating on polyolefin, the low polarity of polyolefin makes it difficult for the coating film to adhere and the coating is difficult.

Known methods for improving the paintability of polyolefin include a method of chemically treating the surface of polyolefin with a chemical or the like, and a method of oxidizing the surface by corona discharge treatment, plasma treatment, flame treatment, or the like. However, these methods have the problem that special equipment is required and the effect of improving paintability is not sufficient.

On the other hand, paints containing modified olefin resins such as so-called chlorinated polyolefins, acid-modified polyolefins, and acid-modified chlorinated polyolefins are known as paints with improved adhesion to polyolefins. Such paints include solvent-based paints in which a modified olefin-based resin is dissolved in an organic solvent, and water-based paints in which a modified olefin resin is dispersed in an aqueous medium. Water-based paints are preferred from the standpoints of safety and health and reduction of environmental pollution.

However, water-based paints containing modified olefin-based resins do not have sufficient performance, and further improvements are being attempted. For example, Patent Document 1 describes a water-based paint containing a composite resin of a modified olefin resin and a polymer obtained by emulsion polymerization of a mixture of vinyl monomers. Patent Documents 2 to 4 describe methods of adding dispersions of urethane resins, acrylic urethane composite resins, acrylic resins, and the like to primers and paints containing modified olefin resins.

In automobiles, electric appliances, etc., along with polyolefin members, non-polyolefin members such as acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as "ABS") and polycarbonate (hereinafter referred to as "PC") are used. is sometimes used. For this reason, paints for polyolefins are sometimes required to have the same paintability as that of polyolefins, even for resins other than polyolefins such as ABS and PC.

Japanese Patent Application Laid-Open No. 2005-23303 JP 2011-16957 A JP-A-2010-53188 JP 2011-195718 A

The water-based paint described in Patent Document 1 has a problem in adhesion. Moreover, the water-based coatings described in Patent Documents 2 to 4 have a problem that the coating film has low water adhesion resistance.

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous coating composition capable of forming a coating film having excellent adhesion to polyolefin substrates, ABS substrates and PC substrates and having water-resistant adhesion.

The present invention has the following aspects.
[1] an olefin resin (A);
containing a hydroxyl group-containing resin (B) (excluding those corresponding to the olefin resin (A)) in a dispersed state,
The hydroxyl-containing resin (B) is selected from the group consisting of a hydroxyl-containing urethane resin (B1), a hydroxyl-containing (meth)acrylic urethane composite resin (B2), and a hydroxyl-containing (meth)acrylic resin (B3). at least one resin that
An aqueous coating composition, wherein the hydroxyl-containing resin (B) has a hydroxyl value of 0.1 to 49 mgKOH/g.
[2] The aqueous coating composition according to [1], wherein the olefin resin (A) contains an olefin composite resin (A3).

According to the water-based coating composition of the present invention, it is possible to form a coating film having excellent adhesion to polypropylene substrates, ABS substrates and PC substrates and having water-resistant adhesion.

The aqueous coating composition of the present invention contains an olefin resin (A) and a hydroxyl group-containing resin (B) in a dispersed state.
As used herein, the term "dispersed state" means that the olefin resin (A) and the hydroxyl group-containing resin (B) are in the state of particles without dissolving in water, a solvent other than water, or a mixed solvent thereof. means it exists.
[Olefin resin (A)]
The olefin-based resin (A) is a resin containing structural units derived from olefin. The content of structural units derived from olefin is preferably 50 mol% or more, more preferably 60 mol% or more, and further preferably 70 mol% or more, based on the total number of moles of the structural units constituting the olefin resin (A). preferable. The higher the content, the higher the adhesion to polyolefin substrates.
Examples of the olefin resin (A) include homopolymers of olefins (hereinafter also referred to as "olefin homopolymers (A1)"), copolymers of olefins and other copolymerizable monomers (hereinafter, Also referred to as "olefinic copolymer (A2)"), and olefinic composite resin (A3).
The olefin homopolymer (A1), the olefin copolymer (A2) and the olefin composite resin (A3) contain reactive groups with amino groups such as carboxy groups, epoxy groups, isocyanato groups, sulfonic acid groups and hydroxyl groups. may have The reactive group may be an acid anhydride structure of a carboxy group.
The olefin-based resin (A) is more preferably an olefin-based resin (A) having a reactive group from the viewpoint of excellent compatibility with the hydroxyl group-containing resin (B) and excellent water adhesion resistance. Hereinafter, the olefin homopolymer (A1) having a reactive group is "polymer (A11)", the olefin copolymer (A2) having a reactive group is "polymer (A21)", and the reactive group is referred to as "polymer (A31)".
Olefins include ethylene, propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, cyclopentene, cyclohexene and norbornene.
Specific examples of the olefin-based copolymer (A2) include copolymers of ethylene and propylene; at least one of ethylene and propylene, and monomers copolymerizable with ethylene and propylene (e.g., butene-1, -1, hexene-1, heptene-1, octene-1, cyclopentene, cyclohexene, norbornene and other α-olefins having 4 or more carbon atoms); from the group consisting of the α-olefins having 4 or more carbon atoms A copolymer of two or more selected α-olefins; an α-olefin having 2 or more carbon atoms and a non-aromatic monomer other than the α-olefin such as vinyl acetate, acrylic acid ester, methacrylic acid ester, etc. copolymers; copolymers of α-olefins having 2 or more carbon atoms and aromatic monomers such as aromatic vinyl monomers, or hydrogenated products thereof; conjugated diene block copolymers or hydrogenated products thereof, etc. is mentioned. Two or more kinds of comonomers other than the olefin may be used.
The olefinic resin (A) may be linear or branched.
From the viewpoint of adhesion to polyolefin substrates, the olefin resin (A) preferably contains a propylene polymer containing a structural unit derived from propylene, such as an ethylene-propylene copolymer, ethylene-propylene-butene. More preferably it contains a copolymer or a propylene-butene copolymer. The content of structural units derived from propylene in the propylene-based polymer is preferably 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more.
The olefinic resin (A) may be chlorinated polyolefin obtained by chlorinating an olefinic resin. In that case, the degree of chlorination of the chlorinated polyolefin is preferably 40% by mass or less, more preferably 30% by mass or less.
In the present specification, the term "copolymer" may be a random copolymer or a block copolymer.

The olefin-based composite resin (A3) includes at least one resin selected from the group consisting of the olefin-based homopolymer (A1) and the olefin-based copolymer (A2), and a resin having a structure different from that of the resin. An integrated composite resin (a31) (hereinafter also referred to as "composite resin (a31)"), or a composite resin ( a32) (hereinafter also referred to as "composite resin (a32)") and the like.
As used herein, the term “unified” means that a plurality of resins having different structures are bonded by chemical interaction (e.g. covalent bond), physical interaction (e.g. intermolecular force), or mechanical interaction. means that
It is preferable that a plurality of resins having different structures are integrated to form a graft polymer, a core-shell structure, a microphase-separated structure, an interpenetrating polymer network structure, or the like.

The melting point Tm (hereinafter referred to as "Tm") of the olefin resin (A) is preferably 125°C or lower, more preferably 100°C or lower, and even more preferably 90°C or lower. Moreover, Tm is preferably 60° C. or higher. The higher the Tm, the less sticky the resin tends to be, and the lower the Tm, the lower the drying and baking temperatures.
In addition, in this specification, melting|fusing point Tm can be measured using the differential scanning calorimeter DSCEXSTAR6000 by Hitachi High-Tech Science.

The weight average molecular weight Mw (hereinafter referred to as "Mw") of the olefin resin (A) is measured by GPC (Gel Permeation Chromatography), converted by the calibration curve of each polyolefin, and ranges from 5,000 to 500,000. is preferably A more preferable lower limit is 10,000, more preferably 20,000, and particularly preferably 30,000. A more preferred value for the upper limit is 300,000. The higher the Mw, the lower the degree of stickiness and the tendency to increase adhesion to the substrate, and the lower the Mw, the lower the viscosity and the easier the preparation of the multi-layer coating composition.
The GPC measurement is performed by a conventionally known method using a commercially available device using ortho-dichlorobenzene or the like as a solvent.

The olefinic resin (A) can be produced, for example, by polymerizing an olefin by a method such as radical polymerization, cationic polymerization, anionic polymerization, or coordination polymerization. Each of these polymerization methods may be a living polymerization method.

Examples of catalysts used for coordination polymerization include Ziegler-Natta catalysts and single-site catalysts. In general, single-site catalysts can have sharp molecular weight distributions and stereoregularity distributions by designing ligands. Single-site catalysts include, for example, metallocene catalysts and Brookhart-type catalysts. Metallocene catalysts include C1 symmetric type, C2 symmetric type, C2V symmetric type, CS symmetric type, etc., and can be appropriately selected depending on the stereoregularity of the desired polyolefin.

The polymerization method may be any method such as solution polymerization, slurry polymerization, bulk polymerization and gas phase polymerization. In the case of solution polymerization or slurry polymerization, solvents include, for example, aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; Examples include halogenated hydrocarbons, esters, ketones, and ethers. Among them, aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons are preferred, and toluene, xylene, heptane and cyclohexane are more preferred. A solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

The olefinic resin (A) having a reactive group can be produced, for example, by graft-polymerizing a radically polymerizable monomer having a reactive group onto an olefinic resin. The radically polymerizable monomer having a reactive group is preferably a radically polymerizable monomer having a carboxy group or an anhydride structure thereof, such as (meth)acrylic acid, fumaric acid, maleic acid and its anhydrides, Examples include itaconic acid and its anhydride, crotonic acid, and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type. Incidentally, (meth)acrylic acid is a general term for acrylic acid and methacrylic acid, and the others follow this.
The olefinic resins used for graft polymerization may be used singly or in combination of two or more.

As the radical polymerization initiator used for graft polymerization, for example, it is possible to appropriately select and use known radical polymerization initiators such as organic peroxides and azonitrile.
Examples of organic peroxides include peroxyketals such as di(t-butylperoxy)cyclohexane, hydroperoxides such as cumene hydroperoxide, dialkyl peroxides such as di(t-butyl)peroxide, and benzoyl peroxide. and peroxy esters such as t-butyl peroxy isopropyl monocarbonate. Azonitriles include azobisbutyronitrile and azobisisopropylnitrile. Preferred radical polymerization initiators are benzoyl peroxide and t-butylperoxyisopropyl monocarbonate. One radical polymerization initiator may be used alone, or two or more thereof may be used in combination.

The ratio of the radical polymerization initiator and the radical polymerizable monomer to be grafted is preferably in the range of radical polymerization initiator: radical polymerizable monomer = 1:100 to 2:1 (molar ratio), 1:20. A range of ~1:1 is more preferred.
The reaction temperature for graft polymerization is preferably 50°C or higher, more preferably in the range of 80 to 200°C. The reaction time for graft polymerization is preferably 2 to 20 hours.

The olefinic resin (A) having a reactive group may be produced by a method other than graft polymerization. Examples of such a production method include a method of reacting an olefin resin and a radically polymerizable monomer in a solution by heating and stirring, a method of melting, heating and stirring without a solvent, and a method of heating and kneading with an extruder. The method of reacting, etc. are mentioned. As the solvent for the production in a solution, the same solvent as described in the production method by solution polymerization of the olefin resin (A) can be used.
As the olefin-based resin (A) having a reactive group, a propylene-based polymer having a reactive group is preferable from the viewpoint of adhesion to a polypropylene substrate.
Specific examples of propylene-based polymers having reactive groups include maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene copolymer, maleic anhydride-modified propylene-butene copolymer, acrylic acid-modified polypropylene, and acrylic acid. Examples include modified ethylene-propylene copolymers, acrylic acid modified propylene-butene copolymers, and chlorinated products thereof.

The content of the reactive group in the olefin resin (A) having a reactive group is preferably in the range of 0.01 to 1 mmol per 1 g of the olefin resin (A), that is, 0.01 to 1 mmol/g. 0.05 to 0.5 mmol/g or more is more preferable, and 0.1 to 0.3 mmol/g is even more preferable.

When the reactive group is an acidic group such as a carboxyl group, its anhydride, or a sulfonic acid group, the higher the content of the reactive group, the higher the acid value of the olefinic resin (A), which improves the mechanical stability. As a result, the polymerizability of the radically polymerizable monomer tends to improve during production. The smaller the content, the more the adhesion of the coating film to the polyolefin substrate tends to increase. The acid value of the olefinic resin (A) can be adjusted by the content of this acidic group.
Neutralizing the acidic group with a basic compound tends to improve the mechanical stability of the olefin resin (A). Examples of the basic compound include inorganic bases such as sodium hydroxide and potassium hydroxide, ammonia, triethylamine, diethylamine, ethanolamine, dimethylethanolamine, 2-methyl-2-amino-propanol, triethanolamine, morpholine. , and pyridine. The neutralization rate of acidic groups is not particularly limited as long as dispersibility in water is obtained, but is preferably 1 to 100 mol %, more preferably 50 mol % or more. A higher neutralization rate tends to improve the dispersibility of the olefin resin (A) in water.

The average particle size of the olefin resin (A) is 200 nm or less, preferably 150 nm or less. More preferably, it is 120 nm or less.
In this specification, the average particle size can be measured using a concentrated particle size analyzer FPAR-1000 manufactured by Otsuka Electronics.

When producing the aqueous coating composition of the present invention, the olefin resin (A) is preferably blended as an aqueous dispersion. The aqueous dispersion of the olefin resin (A) can be prepared by dispersing the olefin resin (A) in an aqueous medium using a surfactant, or by using an olefin homopolymer (A11) or an olefin copolymer (A21). It can be produced by a method of dispersing in an aqueous medium using a composite resin (a31) in which a hydrophilic polymer is integrated with an olefin resin by graft bonding or the like. As the aqueous dispersion of the olefin resin (A), the aqueous dispersion of the composite resin (a31) produced by the latter method is preferable because the coating film has excellent water resistance and stability.

The hydrophilic polymer used for producing the composite resin (a31) refers to a polymer having an insoluble content of 1% by mass or less when dissolved in water at 25° C. at a concentration of 10% by mass. As the water-soluble polymer, any of synthetic polymer, semi-synthetic polymer and natural polymer can be used. The number average molecular weight Mn of this hydrophilic polymer is preferably 300 or more. As this Mn increases, the mechanical stability of the aqueous dispersion of the olefinic resin (A) tends to improve.

As the synthetic polymer, for example, polyether resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin and the like can be used. Examples of the natural polymer include starch, gum arabic, gum tragacanth, casein, gelatin, dextrin, and the like. Examples of the semisynthetic polymer include carboxylated starch, cationized starch, dextrin, ethyl cellulose, carboxylated methyl cellulose, hydroxyethyl cellulose, and cationized cellulose.

As the hydrophilic polymer, a synthetic polymer whose hydrophilicity is easily controlled and whose properties are stable is preferable, and polyvinyl alcohol resin, polyvinylpyrrolidone resin and polyether resin are more preferable. Hydrophilic polymers may be used singly or in combination of two or more. Among them, highly hydrophilic polyether resins are preferred. The average particle size of the composite resin (a31) contained in the aqueous dispersion can be adjusted depending on the type and combination of hydrophilic polymers used.

The polyether resin can be produced, for example, by ring-opening polymerization of a cyclic alkylene oxide or a cyclic alkyleneimine. The polyether resin may be integrated with the olefin-based resin without being bonded to the olefin-based resin, but it is preferable that the polyether resin is integrated with the olefin-based resin in a state of being bonded to it so that it does not bleed out from the coating film.

The polyether resin is obtained by, for example, a method of ring-opening polymerization of a cyclic alkylene oxide in the presence of an olefin resin having a reactive group such as polymer (A11) or polymer (A21), ring-opening polymerization, or the like. It can be integrated in a state of being bonded to the olefin resin by a method of reacting a reactive group such as polyether polyol or polyether amine with a reactive group of the olefin resin having a reactive group.

The polyether polyol is a compound having hydroxyl groups as reactive groups at both ends of a resin having a polyether skeleton. The polyetheramine is a compound having a primary amino group, which is a reactive group, at one end or both ends of a resin having a polyether skeleton. Polyetheramine is preferable as the polyether resin to be integrated with the olefin resin.

The polyether resin preferably contains a hydrophilic structural unit such as polyethylene oxide or polyethyleneimine and a hydrophobic structural unit such as polypropylene oxide or polypropyleneimine. More preferably, it is composed of polyethylene oxide and polypropylene oxide. The HLB (Hydrophile Lipophile Balance) of the polyether resin can be adjusted by adjusting the amounts of hydrophilic structural units and hydrophobic structural units. The polyether resin preferably contains a highly hydrophilic one with an HLB in the range of 9-18.

As for the polyether resin, it is preferable to use a combination of the above-described highly hydrophilic polyether resin and a low hydrophilic polyether resin having an HLB in the range of 1 to 8. The lower the HLB of the polyether resin, the lower the surface energy of the olefin resin integrated with the polyether resin. When producing the composite resin (a32) containing the polymer, the impregnation property of the radically polymerizable monomer tends to be improved. The HLB of the polyether resin having low hydrophilicity is preferably 1-6, more preferably 1-4.

Examples of polyether amines include Huntsman's "Jeffamine" M series, Huntsman D series, Huntsman ED series, and "Surphonamine" L series.

The polyether resin preferably has one or more reactive groups capable of reacting with the olefinic polymer prior to bonding with the olefinic polymer. Such reactive groups include, for example, a carboxylic acid group, a dicarboxylic anhydride group, a dicarboxylic anhydride monoester group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group. is preferred. Amino groups are highly reactive with various reactive groups such as carboxylic acid groups, carboxylic anhydride groups, glycidyl groups, and isocyanate groups, so that the olefinic polymer and the polyether resin can be easily bonded. The amino group may be primary, secondary or tertiary, but is preferably a primary amino group.

The number of reactive groups per molecule of the polyether resin is one or more, preferably one. If there are two or more reactive groups, a three-dimensional network structure may be formed and gelation may occur when bonding with the olefinic polymer. However, even if it has two or more reactive groups, the number of reactive groups may be two or more as long as there is only one reactive group that is more reactive than the others. Such polyether resins include, for example, polyether resins having a hydroxyl group and one amino group with higher reactivity. Here, reactivity means reactivity with the reactive group of the olefinic polymer.

The polyether resin preferably has a weight average molecular weight Mw of 200 to 200,000, more preferably 300 to 100,000, even more preferably 500 to 10,000, further preferably 500 to 3 ,000 is particularly preferred. The higher the Mw, the lower the surface energy of the composite resin (a31), which tends to improve the wettability, and the lower the Mw, the lower the viscosity of the aqueous dispersion of the composite resin (a31). tends to be easy. GPC measurement can be performed by a known method using a commercially available device using THF or the like as a solvent.

The composite resin (a31) is an olefin resin having a reactive group such as the polymer (A11) or the polymer (A21) and a polyether resin having a reactive group. It is preferable to combine and integrate at a ratio of 1 to 100:100 (mass ratio). This mass ratio is more preferably 100:5 to 100:70, even more preferably 100:10 to 100:50. In regions where the proportion of the polyether resin is low, the particle size of the composite resin (a31) tends to decrease as the proportion increases. Therefore, when producing a composite resin (a32) containing this composite resin (a31) and a polymer containing a radically polymerizable monomer having a reactive group as a structural unit, polymerization of the radically polymerizable monomer tend to improve. In the region where the proportion of the polyether resin is high, the lower the proportion, the more the acid value of the composite resin (a31) increases, and the polymerizability of the radically polymerizable monomer for producing the composite resin (a32) tends to improve. Also, the adhesion of the coating film to polyolefin substrates tends to be improved.

As a method for obtaining an aqueous dispersion by dispersing the olefin resin (A) in an aqueous medium, for example, a solvent other than water is added to the olefin resin (A), dissolved by appropriate heating, and then water is added. methods and the like. This method has the advantage of being easy to produce an aqueous dispersion with a small particle size. The temperature for dissolving in the solvent and adding water is preferably 30 to 150°C, more preferably 50 to 100°C. Solvents other than water may be distilled off after adding water.

The amount of solvent other than water contained in the aqueous dispersion of the olefin resin (A) is preferably 50% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly 1% by mass or less. preferable. As the solvent other than water, the above-described solvents can be used. Among them, a solvent that dissolves in water at 1% by mass or more is preferable, and a solvent that dissolves at 5% by mass or more is more preferable. Preferred solvents include, for example, methyl ethyl ketone, cyclohexanone, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, cyclohexanol, tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2- Methoxypropanol and 2-ethoxypropanol and the like can be mentioned.

The apparatus for producing the aqueous dispersion by adding water after dissolving in the solvent is not particularly limited. The stirring speed at that time varies somewhat according to the selection of the device, but is usually in the range of 10 to 1000 rpm.
If the stirring speed is lower than the lower limit, the particle size of the polyolefin resin dispersion tends to increase.

The olefin-based resin (A) preferably contains an olefin-based composite resin (A3).
The olefin-based composite resin (A3) includes at least one resin selected from the group consisting of the olefin-based homopolymer (A1) and the olefin-based copolymer (A2), and a hydrophilic polymer such as a polyether resin. and a composite resin (a31) integrated with the composite resin (a31), and a composite resin (a32 ) is preferred.
Examples of the radically polymerizable monomer having a reactive group include hydroxyl group-containing radically polymerizable monomers: 3-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxy methacrylate Epoxy group-containing radically polymerizable monomers such as propyl, 4-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2-hydroxybutyl methacrylate, polypropylene glycol acrylate, polypropylene glycol methacrylate, etc. : glycidyl methacrylate and 4-hydroxybutyl glycidyl ether acrylate. 2-Hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and glycidyl methacrylate are preferred because of their excellent adhesion to polyolefin substrates.

When the olefin-based composite resin (A3) has hydroxyl groups, the hydroxyl value of the olefin-based composite resin (A3) is preferably 0.01 to 100 mgKOH/g. More preferably 0.05 to 80 mgKOH/g, particularly preferably 0.1 to 50 mgKOH/g. There is a tendency that the lower the hydroxyl value, the better the adhesion to the polypropylene substrate. Hydroxyl value is calculated by Equation 1.
[Formula 1]
Hydroxyl value (mgKOH/g) = (f x M1/Mw/M2 x [KOH] x 1,000)
f: number of hydroxyl groups in hydroxyl-containing monomer [KOH]: molecular weight of KOH M1: mass of hydroxyl-containing monomer (g)
M2: Solid mass (g) of olefin composite resin (A3)
Mw: molecular weight of hydroxyl group-containing monomer (number average molecular weight)

When having a hydroxyl group as a reactive group, the content of the polymer having a structural unit derived from a radically polymerizable monomer having a reactive group is preferably It is 0.01 to 50% by mass, more preferably 0.05 to 40% by mass, and particularly preferably 0.1 to 30% by mass. The smaller the content, the more the adhesion to the polyolefin substrate tends to improve. The higher the content, the more the water resistance tends to improve.

When having an epoxy group as a reactive group, the content of the polymer having a structural unit derived from a radically polymerizable monomer having a reactive group is preferably based on the total mass of the olefin-based composite resin (A3). is 0.01 to 50% by mass, more preferably 0.05 to 40% by mass, and particularly preferably 0.1 to 30% by mass. The smaller the content, the more the adhesion to the polyolefin substrate tends to improve. The higher the content, the more the water resistance tends to improve.

A polymer having a structural unit derived from a radically polymerizable monomer having a reactive group has excellent polymerizability with a radically polymerizable monomer having a reactive group. It may contain derived structural units. Vinyl monomers include (meth) acrylic monomers such as (meth) acrylic acid and (meth) acrylic acid esters; aromatic monomers such as styrene and α-methylstyrene; (meth) acrylamide , dimethyl(meth)acrylamide; and the like; (meth)acrylonitrile, vinyl acetate, vinyl propionate, vinyl versatate and the like.

Of these, (meth)acrylic monomers and aromatic monomers are preferred from the viewpoint of weather resistance and solvent resistance. Specific examples of (meth) acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylic acid-n-butyl, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, (meth)acrylic acid- 2-ethylhexyl, nonyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc., or (meth)acrylic acid esters having an aryl or aralkyl group having 6 to 12 carbon atoms, such as (meth) ) benzyl acrylate, etc., dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-aminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2-methoxy (meth)acrylate (meth)acrylic acid esters having an alkyl group containing a fluorine atom and having 1 to 20 carbon atoms, such as ethyl, 3-methoxypropyl (meth)acrylate, adducts of (meth)acrylic acid and polyethylene oxide; Examples include trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, and 2-perfluoroethylethyl (meth)acrylate. Specific examples of aromatic monomers include styrene and α-methylstyrene.

[Surfactant]
The aqueous dispersion of the olefinic resin (A) used in producing the aqueous coating composition of the present invention may contain a surfactant for the purpose of improving storage stability. Surfactants include various anionic, cationic, or nonionic surfactants, as well as polymeric surfactants. A so-called reactive surfactant having an ethylenically unsaturated bond can also be used as the surfactant. Among these, it is preferable to use an anionic surfactant from the viewpoint of improving the storage stability of the resulting aqueous dispersion. The anionic surfactant is not particularly limited, but can be used, for example, Adekari Soap SR, which is a reactive surfactant manufactured by ADEKA Corporation, and Neocol SW-C, which is a non-reactive surfactant.

Further, the surfactant is preferably contained in an amount of 2 parts by mass or less with respect to 100 parts by mass of the radically polymerizable monomer. Furthermore, it is preferably 1 part by mass or less. It is particularly preferably not contained. By setting the amount to 2 parts by mass or less, the stability during formulation into a paint can be maintained without impairing the water resistance.

[Method for producing olefin composite resin (A3)]
The method for producing the olefin-based composite resin (A3) is not particularly limited. A method of polymerizing a monomer to integrate a polymer containing a structural unit derived from a radically polymerizable monomer, an olefin homopolymer (A1), an olefin copolymer (A2) or a composite resin A method of dispersing (a31) and a radically polymerizable monomer in an aqueous medium to form an aqueous resin dispersion and then polymerizing and integrating the radically polymerizable monomer can be used. From the viewpoint of the polymerizability of the radically polymerizable monomer, the former is preferable.

The most preferred method for producing the olefin-based composite resin (A3) is to add a radically polymerizable monomer and a vinyl A method of supplying 80 to 100% by mass of the system monomer at once and polymerizing with a water-soluble initiator, or a method of polymerizing with a redox initiator using an organic peroxide and a reducing agent such as sodium thiosulfate. It is a method to let

As the initiator, those generally used for radical polymerization can be used, and specific examples thereof include potassium persulfate, sodium persulfate, persulfates such as ammonium persulfate, azobisisobutyronitrile, 2, 2′-azobis(2-methylbutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2 - Oil-soluble azo compounds such as phenylazo-4-methoxy-2,4-dimethylvaleronitrile and 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl ]propionamide}, 2,2′-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionamide}, 2,2′-azobis{2-methyl-N-[2-(1 -hydroxybutyl)]propionamide}, 2,2′-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] and its salts, 2,2′-azobis[2-(2-imidazoline -2-yl)propane] and salts thereof, 2,2′-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} and salts thereof, 2,2′-azobis (2-methylpropyne amidine) and its salts, water-soluble azo compounds such as 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionamidine], benzoyl peroxide, cumene hydroperoxide, Examples include organic peroxides such as t-butyl hydroperoxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate and the like. These initiators can be used alone, and can also be used as a mixture of two or more.

Moreover, the polymerization temperature is preferably 50° C. or higher from the viewpoint of the polymerization rate of the resulting aqueous resin dispersion. In this case, it is preferable to use sodium bisulfite, ferrous sulfate, isoascorbate, Rongalite or other reducing agent as an initiator in combination with a water-soluble radical polymerization catalyst.

The polymerization time is preferably 30 minutes or longer. If the time is less than 30 minutes, the radically polymerizable monomer is not sufficiently polymerized, and the polymerization rate tends to be poor. Also, the polymerization time is preferably 3 hours or less. If the time exceeds 3 hours, a large amount of cullet is produced during the polymerization, and the production stability tends to be poor.

Further, in the present invention, known chain transfer agents such as n-dodecylmercaptan, t-dodecylmercaptan and α-methylstyrene dimer can be used as molecular weight modifiers.

After the completion of the emulsion polymerization, it is cooled, and when the product emulsion is taken out, it is preferable to perform a filtration operation to prevent contamination of foreign matter and cullet. As for the filtration method, a known method can be used, and for example, nylon mesh, bag filter, filter paper, metal mesh, etc. can be used.

[Hydroxyl group-containing resin (B)]
In the present invention, the hydroxyl-containing resin (B) includes a urethane resin (B1) having a hydroxyl group (hereinafter also simply referred to as "urethane resin (B1)"), a (meth) acrylic urethane composite resin (B2) having a hydroxyl group (hereinafter also referred to as "urethane resin (B1)"). , simply referred to as "(meth)acrylic urethane composite resin (B2)"), and a (meth)acrylic resin (B3) having a hydroxyl group (hereinafter simply referred to as "(meth)acrylic resin (B3)"). and having a hydroxyl value of 0.1 to 49 mgKOH/g. However, among the hydroxyl group-containing resins (B), those that also correspond to the olefinic resin (A) shall be classified as the olefinic resin (A). Among them, the urethane resin (B1) and the acrylic urethane composite resin (B2) are preferable because of their excellent smoothness and appearance. Furthermore, the acrylic urethane composite resin (B2) is more preferable because of its excellent appearance and flexibility.

In the present invention, the hydroxyl value of the hydroxyl-containing resin (B) is preferably 0.1 mgKOH/g to 40 mgKOH/g, more preferably 10 mgKOH, from the viewpoint of excellent compatibility with the olefin resin (A) and excellent water adhesion resistance. /g to 40 mgKOH/g, particularly preferably 17 mgKOH/g to 40 mgKOH/g.

[Urethane resin (B1)]
The urethane resin (B1) is obtained by reacting a diol with a polyvalent isocyanate compound.

A diol refers to an organic compound having two hydroxyl 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; at least one of these diols and , adipic acid, sebacic acid, itaconic acid, maleic anhydride, terephthalic acid, polyester diols obtained by polycondensation of at least one dicarboxylic acid such as isophthalic acid; Polyether diols such as ether diols and polycarbonate diols; polybutadiene diols, hydrogenated polybutadiene diols, polyacrylate diols, and the like. These diols may be used singly or in combination of two or more.

A polyvalent isocyanate compound refers to an organic compound having at least two isocyanate groups in one molecule, and includes polyvalent isocyanate compounds such as aliphatic, alicyclic, and aromatic compounds. Specific examples of polyisocyanate compounds 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. At the time of producing the urethane resin (B11), these polyvalent isocyanate compounds may be used singly or in combination of two or more.

As a method for producing the urethane resin (B1), for example, the diol described above and isocyanate are reacted in an ether such as dioxane using a catalyst such as dibutyltin dilaurate, and water is added to disperse the reaction. mentioned.
The weight-average molecular weight of the urethane resin dispersion obtained by such a method is preferably 500 or more, more preferably 1000 or more, from the viewpoint of improving the reactivity with the radically polymerizable monomer described later. more preferred. The upper limit is preferably 500,000 or less, more preferably 400,000 or less. That is, the weight average molecular weight of the urethane resin dispersion is preferably 500 to 500,000, more preferably 1000 to 400,000. Here, "mass average molecular weight" means a value calculated by polystyrene conversion using gel permeation chromatography.

The urethane resin (B1) is preferably in the form of an aqueous dispersion, as described above, in that the radically polymerizable monomer mixture described below can be stably polymerized.
The average particle size of the urethane resin (B1) 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 aqueous coating composition, 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 viewpoint of paint viscosity properties and storage stability when used in a water-based paint composition. That is, as the aqueous dispersion of the urethane resin (B1), it is preferable to use an aqueous dispersion in which the urethane resin (B1) having an average particle size of 10 to 1000 nm, preferably 10 to 500 nm, is dispersed in water. .

The content (solid content) of the urethane resin (B1) in the aqueous dispersion is preferably 10% by mass or more, more preferably 25% by mass or more. Moreover, it is preferably 70% by mass or less, more preferably 60% by mass or less. That is, the content of the urethane resin (B1) in the aqueous dispersion is preferably 10-70% by mass, more preferably 25-60% by mass, relative to the total mass of the aqueous dispersion. With such a content, the solid content concentration of the polymer dispersion obtained by polymerizing the radically polymerizable monomer mixture in the water dispersion of the urethane resin (B1) should be in the range of 10 to 80% by mass. Adjustable. If the solid content concentration of the polymer dispersion is within the above range, good paintability will be achieved when this is used as a water-based paint composition.

As such an aqueous dispersion of the urethane resin (B1), a commercially available urethane aqueous polymer dispersion (urethane dispersion: PUD) can be used as it is. Specifically, manufactured by 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 Covestro Urethane Co., Ltd.: Bihydrol UH2606, Bihydrol UH650, Bihydrol UHXP2648, Bihydrol UHXP2650, Impranil DLC- F, Impranil DLN, Impranil DLP-R, Impranil DLS, Impranil DLU, Impranil XP2611, Impranil LPRSC1380, Impranil LPRSC1537, Impranil LPRSC1554, Impranil LPRSC3040, Impranil LPDSB1069, manufactured by DIC Corporation: 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 Chemical Industries Co., Ltd.: Yukote UWS-145, Permaline UA-150, Permaline UA-200, Permaline UA-300, Permaline UA-310, Yukote UX-320 , Permaline UA-368, Permaline UA-385, Ukote UX-2510, manufactured by Nicca Chemical Co., Ltd.: Evaphanol 170, Evaphanol N-33, Evaphanol AP-6, Evaphanol AP-12, Evaphanol AP-24, Evaphanol AL- 3, Evaphanol APC-55, Evaphanol APC-66, Evaphanol HA-100, Evaphanol HA-11, Evaphanol HA-15, Evaphanol HA-50C, Evaphanol HO-10, Evaphanol HO-10PT, Evaphanol HO-18, Evaphanol N, Evaphanol N-20, Evaphanol N-7, Evaphanol N-88, Evaphanol AS-12, Evaphanol AS-21, Evaphanol AS-47 ADEKA Co., Ltd.: Adeka Bontiter UHX-210, ADEKAボンタイターＵＨＸ－２８０、ダイセル・オルネクス（株）製ＤＡＯＴＡＮ ＶＴＷ１２２５／４０ＷＡ、ＴＷ１２２７／４０ＷＡ、ＶＴＷ１２３３／３６ＷＡＮＭＰ、ＶＴＷ１２３７／３２ＷＡＮＭＰ、ＶＴＷ１２６５／３６ＷＡ、ＶＴＷ１６８６／４０ＷＡ、ＴＷ６４２５／４０ＷＡ、ＴＷ６４２９／４０ＷＡ、ＴＷ６４５０／４０ＷＡ、ＶＴＷ６４６０ /35WA, VTW6462/35WA, VTW6463/35WA, TW6464/35WA, TW6492/35WA, TW6493/35WA, TW7225/40WA and the like. Among them, when the urethane resin dispersion (B11) is used alone, it contains hydroxyl groups, so it is manufactured by Nicca Chemical Co., Ltd. DAOTAN VTW1225/40WA, TW1227/40WA, VTW6425/40WA, TW6429/40WA, VTW6462/35WA, VTW6463/35WA, TW6464/35WA and TW7225/40WA manufactured by DAOTAN Co., Ltd. are preferable.

[(Meth) acrylic urethane composite resin (B2)]
The (meth)acrylic urethane composite resin (B2) may be formed by integrating a (meth)acrylic resin and a urethane resin to form a composite resin. For example, a composite resin obtained by polymerizing a (meth)acrylic monomer in the presence of a urethane resin is preferred.
In the method for producing the (meth)acrylic urethane composite resin (B2), a method of polymerizing a (meth)acrylic monomer in an aqueous dispersion in which a urethane resin is dispersed in water is preferred. In this case, the urethane resin preferably has at least one of a carboxy group and a sulfonic acid group in its structure. This is preferable because the dispersibility of the urethane resin in water is improved.
The dispersion medium may be water contained in the aqueous dispersion of the urethane resin (A).
The urethane resin more preferably has a sulfonic acid group in its structure from the viewpoint that the (meth)acrylic monomer can be stably polymerized in the aqueous dispersion of the urethane resin. As a result, a dispersion of a (meth)acrylic urethane composite resin (B2) in which a urethane resin having a sulfonic acid group and a polymer obtained by polymerizing a (meth)acrylic monomer are contained in the same particles. can be stably obtained.

In one aspect of this dispersion production method, when the (meth)acrylic monomer contains an acid group-containing (meth)acrylic monomer having an acid group such as a carboxy group, polymerization during emulsion polymerization It is preferable because it improves stability. In addition, when the obtained polymer dispersion is used as a water-based coating composition, the storage stability is improved, and a coating film having excellent water resistance and hydrolysis resistance can be formed, which is preferable.

(Meth)acrylic monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 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, iso Alkyl (meth)acrylates having an alkyl group having 1 to 22 carbon atoms such as stearyl (meth)acrylate; Cycloalkyls such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate (Meth)acrylates; 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-(acryloxypolyethoxy)phenyl]propane, 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, hydroxyalkyl (meth)acrylate such as hydroxy(meth)acrylate added to diglycidyl ether of bisphenol A Epoxy (meth) acrylate, diol such as polyoxyalkylenated bisphenol A di (meth) acrylate and diester compound of (meth) acrylic acid; Rimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate Compounds having 3 or more hydroxyl groups per molecule such as acrylates and dipentaerythritol hexa(meth)acrylate and polyester compounds of (meth)acrylic acid; ) Diallyl phthalate, diallyl isocyanurate, diallyl maleate tris(2-acryloyloxyethylene) isocyanurate, ε-caprolactone-modified tris(acryloxyethyl) isocyanurate, 1,3-butadiene, conjugated diene monomers such as isoprene acid group-containing radically polymerizable monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate; - hydroxyl group-containing radically polymerizable monomers such as hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, γ-(meth) Hydrolyzable silyl group-containing radically polymerizable monomers such as acryloyloxypropylmethyldimethoxysilane and γ-(meth)acryloyloxypropyltrimethoxysilane; Alkyl group-terminated polyalkylene oxides such as methoxypolyethylene oxide mono(meth)acrylate group-containing radically polymerizable monomers; oxirane group-containing radically polymerizable monomers such as glycidyl (meth)acrylate; carbonyl group-containing ethylenically unsaturated monomers such as diacetone acrylamide; 6-pentamethyl-4-piperidyl (meth)acrylate, 2,2,6,6-pentamethyl-4-piperidyl (meth)acrylate having a light stabilizing action; 2-[2'-hydroxy- 5′-(meth)acryloyloxyethylphenyl]-2H-benzotriazole (meth)acrylate having an ultraviolet absorbing component; aminoalkyl (meth)acrylates such as 2-aminoethyl (meth)acrylate; (meth) containing amide groups such as acrylamide Radically polymerizable monomers; metal-containing radically polymerizable monomers such as zinc di(meth)acrylate; (meth)acrylonitrile, benzyl (meth)acrylate, isobornyl (meth)acrylate, methoxyethyl (meth)acrylate, etc. and other (meth)acrylic monomers. These may be used individually by 1 type, and may use 2 or more types together.
As used herein, the term "monomer mixture" means containing one or more of the above (meth)acrylic monomers. That is, the radically polymerizable monomer mixture includes those containing only one type of radically polymerizable monomer.

In addition, the (meth)acrylic monomer may contain an appropriate amount of an acid group-containing (meth)acrylic monomer. As described above, the inclusion of the acid group-containing radically polymerizable monomer is preferable because it improves the formulation stability and storage stability of the water-based coating composition and the oil and fat resistance of the coating film. From the viewpoint of polymerization stability, the monomer mixture Y preferably contains an acid group-containing (meth)acrylic monomer.
The ratio of the acid group-containing (meth)acrylic monomer is preferably 0.01 to 5% by mass with respect to the total mass of the (meth)acrylic monomer. If the proportion of the acid group-containing (meth)acrylic monomer is 5% by mass or more, the resulting polymer Z will have a high polarity, and in particular the adhesion to polyolefin substrates will be reduced. The proportion of the acid group-containing radically polymerizable monomer is more preferably 0.02 to 4% by mass, more preferably 0.03 to 3% by mass, relative to the total mass of the monomer mixture X and the monomer mixture Y. % is more preferred.

In the method for producing a dispersion of a (meth)acrylic urethane composite resin (B2), a monomer mixture X composed of one or more (meth)acrylic monomers is polymerized in the presence of a urethane resin to form a polymer. A production method for obtaining a dispersion containing (B2a), and a monomer mixture Y containing one or more (meth)acrylic monomers is further added to the polymer (B2a) to polymerize. and a method for producing a dispersion containing coalescence (B2b).

Polymer (B2a)
The mass ratio of the urethane resin (B1) and the polymer of the monomer mixture X in the polymer (B2a) is urethane resin (B1)/(monomer mixture X polymer)=10/90 to 90/ 10 is preferred, 20/80 to 80/20 is more preferred, and 30/70 to 70/30 is particularly preferred. In this case, the total mass of the urethane resin (B1) and the polymer of the monomer mixture X is 100.

If the mass ratio of the urethane resin (B1) is in the range of 10 to 90% by mass with respect to the above-mentioned total mass (100% by mass), the coating film can be formed without reducing the resin compatibility and the washability of the coating machine. It is preferable because it improves the adhesiveness, water resistance, and solvent resistance. In particular, if it is in the range of 20 to 70% by mass, the adhesion of the coating film is further improved.

The polymer (B2a) is a polymer particle having an average particle diameter of 10 to 1000 nm from the viewpoint of film-forming properties, adhesion, water resistance, water absorption resistance, hydrolysis resistance, and solvent resistance of the coating film. polymer particles having an average particle diameter of 20 to 500 nm, more preferably polymer particles having an average particle diameter of 30 to 400 nm.

Polymer (B2b)
The mass ratio of the polymer of the urethane resin (B1) and the polymer of the monomer mixture X and the monomer mixture Y in the polymer (B2b) is urethane resin (B1)/(monomer mixture X and monomer mixture Y polymer) is preferably from 10/90 to 90/10, more preferably from 20/80 to 80/20, and particularly preferably from 30/70 to 70/30. In this case, the total mass of the urethane resin (B1) and the polymer of the monomer mixture X and the monomer mixture Y is 100.
If the mass ratio of the urethane resin (B1) in the polymer (B2b) is in the range of 10 to 90% by mass with respect to the above-mentioned total mass (100% by mass), resin compatibility and coating machine washability are improved. It is preferable because it improves the adhesion, water resistance, and solvent resistance of the coating film without lowering it. In particular, if it is in the range of 20 to 70% by mass, the adhesion of the coating film is further improved.

The polymer (B2b) is a polymer particle having an average particle diameter of 10 to 1000 nm from the viewpoint of film-forming properties, adhesion, water resistance, water absorption resistance, hydrolysis resistance, and solvent resistance of the coating film. polymer particles having an average particle diameter of 20 to 500 nm, more preferably polymer particles having an average particle diameter of 30 to 400 nm. In this specification, the average particle size of the polymer (B2b) is measured at room temperature using a concentrated particle size analyzer FPAR-1000 manufactured by Otsuka Electronics Co., Ltd., and is a value calculated by cumulant analysis. .

[Polymerization initiator]
As the polymerization initiator used for the polymerization of the urethane resin (B1) and the monomer mixture X and the polymerization of the polymer (B2a) and the monomer mixture Y, those generally used for radical polymerization can be used. and, for example, potassium persulfate, sodium persulfate, persulfates such as ammonium persulfate, azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis ( 2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile and other oil-soluble azo compounds 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2′-azobis{2-methyl-N-[2 -(1-hydroxyethyl)]propionamide}, 2,2′-azobis{2-methyl-N-[2-(1-hydroxybutyl)]propionamide}, 2,2′-azobis[2-(5 -methyl-2-imidazolin-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 its salts, 2,2'-azobis(2-methylpropionamidine) and its salts, 2,2' -water-soluble azo compounds such as azobis [N-(2-carboxyethyl)-2-methylpropionamidine] and salts thereof; benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxy- Organic peroxides such as 2-ethylhexanoate and t-butyl peroxyisobutyrate are included.
These initiators may be used individually by 1 type, or may use 2 or more types together.

The addition amount of the radical polymerization initiator used in the production of the polymer (B2a) is preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the total mass of the monomer mixture X. Considering 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 Z, it is more preferably 0.005 to 1 part by mass. In addition, from the viewpoint of reducing the coarse particle rate of the finally obtained polymer dispersion, the is 0.005 to 0.09 parts by mass.
Here, the "coarse particle rate" means that the polymer coalesces during polymerization and becomes particles with an average particle size exceeding 1 μm. It can be evaluated by measuring the mass 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 production of the polymer (B2b) is preferably 0.01 to 10 parts by weight per 100 parts by weight of the total weight of the monomer mixture Y. Among them, 0.02 to 5 parts by mass is more preferable in consideration of progress of polymerization and control of reaction.

[Reducing agent]
In the production of polymer (B2a) and polymer (B2b), 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 are considered from the viewpoint of the progress of polymerization, the wettability to the substrate when applying the water-based coating composition, the water resistance of the coating film, the weather resistance, and the solvent resistance. It is more preferable to employ a combination of such as ferrous sulfate, ascorbate, and the like.

[emulsifier]
In the production of polymer (B2a) and polymer (B2b), an emulsifier can be used as necessary. The use of an emulsifier can improve polymerization stability during emulsion polymerization and reduce aggregates. In this case, the resulting polymer dispersion will contain an emulsifier.
The content of the emulsifier is usually preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of the total mass of the monomer mixture X or the monomer mixture Y. parts by mass, more preferably 0.5 to 2 parts by mass. As the emulsifier, the following anionic, cationic, nonionic surfactants and reactive surfactants can be used.

Anionic surfactants include potassium oleate, sodium laurate, sodium dodecylbenzenesulfonate, sodium alkanesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl Non-reactive surfactants such as sodium allyl ether sulfate, polyoxyethylene alkyl phosphates, polyoxyethylene alkylallyl phosphates, and alkylaryl sulfosuccinates (for example, manufactured by Sanyo Chemical Co., Ltd.: Eleminol (registered trademark) JS- 2, JS-20, manufactured by Kao Corporation: Latemul (registered trademark) S-180A, S-180, etc.), polyoxyethylene alkylpropenylphenyl ether sulfate ester ammonium salt (for example, Daiichi Kogyo Seiyaku ( manufactured by Aqualon (registered trademark) HS-10, HS-5, BC-10, BC-5, etc.), 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.: Adekaria Soap (registered trademark) SE-10, SE-1025A, etc.), poly Oxyethylene-1-(allyloxymethyl)alkyl ether sulfate ester ammonium salt (for example, Daiichi Kogyo Seiyaku Co., Ltd.: Aqualon (registered trademark) KH-10, etc.), α-sulfo-ω-(1 -(alkoxy)methyl-2-(2-propenyloxy)ethoxy)-poly(oxy-1,2-ethanediyl)ammonium salt (for example, Asahi Denka Kogyo Co., Ltd.: Adekaria Soap (registered trademark) SR-10) , SR-1025, etc.), polyoxyalkylene alkenyl ether sulfate ammonium salts (e.g., manufactured by Kao Corporation: Latemul (registered trademark) PD-104, etc.) and other reactive surfactants. .

Cationic surfactants include non-reactive surfactants such as stearylamine hydrochloride, lauryltrimethylammonium chloride, and trimethyloctadecylammonium chloride.

Nonionic surfactants include non-reactive surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethyleneoxypropyl block polymers, polyethylene glycol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and α- Hydro-ω-(1-alkoxymethyl-2-(2-propenyloxy)ethoxy)-poly(oxy-1,2-ethanediyl)) (manufactured by Asahi Denka Kogyo Co., Ltd.: Adekari Soap ER-10, ER- 20, ER-30, ER-40), polyoxyethylene alkylpropenyl phenyl ether (Daiichi Kogyo Seiyaku Co., Ltd.: Aqualon RN-20, RN-30, RN-50), polyoxyalkyl alkenyl ether (Kao ( Co., Ltd.: Latemul PD-420, PD-430, PD-450) and other reactive surfactants.

Moreover, an amphoteric surfactant can also be used as an amphoteric component.
One or more of these emulsifiers can be selected and used.

[Basic compound]
In the method for producing a polymer dispersion, it is preferable to add a basic compound after producing the polymer (B12b) to adjust the pH to about 6.0 to 11.0. This improves the stability of the resulting polymer dispersion and the storage stability of the aqueous coating composition.
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 Aminoethanol, ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, 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]
A polymer dispersion can be obtained by the production method described above.
The polymer dispersion is obtained by dispersing the polymer (B12b) in a dispersion medium. The dispersion medium may be water contained in the aqueous dispersion of the urethane resin (B1) described above, water contained in the emulsion containing the monomer mixture, or a solvent used in the aqueous coating composition described below. .
The solid content concentration in the polymer dispersion 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 and the final solid content when forming a water-based coating composition.

[(Meth) acrylic resin (B3)]
The (meth)acrylic resin (B3) may be a resin (B3) containing a structural unit derived from a (meth)acrylic monomer.

The method for producing the (meth)acrylic resin (B3) is not particularly limited, but a monomer mixture X comprising one or more (meth)acrylic monomers is polymerized to obtain a dispersion containing the polymer (B3a). a production method for obtaining a polymer, and a monomer mixture Y containing one or more (meth)acrylic monomers is further added to the polymer (B3a) and polymerized to obtain the polymer (B3b). A production method for obtaining a dispersion is preferably a method for producing a polymer dispersion.

[Aqueous paint composition]
The water-based coating composition of the present invention is a water-based coating composition containing an olefin resin (A) and a hydroxyl group-containing resin (B) in a dispersed state, wherein the hydroxyl group-containing resin (B) has a hydroxyl value of 0.1. Any water-based paint composition having a concentration of up to 49 mgKOH/g may be used, and any production method may be used.
The method for producing the aqueous coating composition of the present invention includes, for example, preparing an aqueous dispersion of the olefin resin (A), preparing an aqueous dispersion of the hydroxyl group-containing resin (B), and mixing the aqueous dispersion of (A) and the aqueous dispersion of the hydroxyl group-containing resin (B).

The mass ratio of the olefin resin (A) to the hydroxyl group-containing resin (B) (hereinafter also referred to as "(A)/(B) ratio") is (A)/(B) = 10/90 to 90/10 ( solid content mass), more preferably (A)/(B) = 15/85 to 70/30, and particularly preferably (A)/(B) = 20/80 to 60/40.
When the (A)/(B) ratio is equal to or less than the above upper limit, there is a tendency that adhesion to ABS substrates and PC substrates is improved.
When the (A)/(B) ratio is at least the above lower limit, there is a tendency for good adhesion to polyolefin substrates.

The aqueous coating composition obtained by the production method of the present invention can be used for primers, paints, adhesives, ink binders and the like, and can be particularly useful for paints, inks and adhesives. Applications include automobile paints for interior and exterior use, paints for home appliances such as mobile phones and personal computers, paints for building materials, and heat sealing agents. Especially preferred are primers for polyolefin substrates, ABS substrates and PC substrates.

The aqueous coating composition of the present invention preferably further contains various additives. Additives include, for example, various pigments, resin beads, antifoaming agents, pigment dispersants, leveling agents, anti-sagging agents, curing catalysts, matting agents, UV absorbers, light stabilizers, antioxidants, heat resistance Various additives such as improvers, slip agents, preservatives, plasticizers, thickeners, wetting agents, and solvents can be used, and one or more of them can be used.
In addition, other polymer particles (for example, polyester resins, polyurethane resins, acrylic resins, acrylic silicone resins, silicone resins, fluorine resins, epoxy resins, polyolefin resins, alkyd Dispersed particles made of other polymers such as resins), water-soluble resins/viscosity control agents, amino resins, polyisocyanate compounds, blocked polyisocyanate compounds, melamine resins, urea resins, carboxy group-containing compounds, carboxy group-containing resins, Curing agents such as epoxy group-containing resins, epoxy group-containing compounds, and carbodiimide group-containing compounds may be mixed.

Examples of pigments include coloring pigments, extender pigments, luster pigments, and the like.
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, threne pigments, perylene pigments, and the like. is mentioned.
Examples of extender pigments include clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white.
Luster pigments include, for example, 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 flakes, and holograms. A pigment etc. are mentioned. One or more of these can be used.

The aqueous coating composition of the present invention may further contain a solvent. As the solvent, those commonly used for water-based paints can be used. Such solvents include, for example, water, linear, branched or cyclic aliphatic alcohols having 5 to 14 carbon atoms; alcohols containing aromatic groups; general formula HO--(CH _CHXO ); Represented by _p -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.) Monoethers such as (poly)ethylene glycol or (poly)propylene glycol; general formula R ⁵ COO-(CH ₂ CHXO) _q —R ⁶ (R ⁵ and R ⁶ are straight chain having 1 to 10 carbon atoms or a branched alkyl group, 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 ester; Aromatic organic solvents such as toluene and xylene; 2,2,4-trimethyl-1,3-pentanediol mono- or diisobutyrate, 3-methoxybutanol, 3-methoxybutanol acetate, 3-methyl-3-methoxy butanol, 3-methyl-3-methoxybutanol acetate and the like.
Among these, linear, branched or cyclic aliphatic alcohols having 5 to 14 carbon atoms are preferred, alcoholic solvents having 7 to 14 carbon atoms are more preferred, and 1-octanol, 2-octanol, 2- At least selected from the group consisting of 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 One alcoholic solvent is particularly preferred.

The present invention will be described in more detail below with reference to examples and comparative examples. In addition, "
"Parts" means "parts by mass". Moreover, evaluation was performed by the method shown below.

<Evaluation of polyolefin resin dispersion>
1. Average Particle Size The average particle size of the polyolefin resin dispersion was determined using a concentrated particle size analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).

<Evaluation of aqueous resin dispersion>
1. Polymerization Rate of Radically Polymerizable Monomer After polymerization of the radically polymerizable monomer, the polymerization rate (% by mass) at the time of polymerization of the radically polymerizable monomer is calculated from general formula 1 from the solid content of the aqueous resin dispersion (C). Calculated.
Polymerization rate (% by mass) = (total solid amount - solid content of urethane resin dispersion) / (amount of radically polymerizable monomer charged)
○: polymerization rate 100 to 96% by mass
△: polymerization rate 95 to 90% by mass
×: less than 90% by mass polymerization rate

2. Initial adhesion (paint preparation)
3 parts by mass of TEGO WET KL-245 (manufactured by EVONIK) was added as a substrate wetting agent to the solid content of the aqueous resin dispersion, and the mixture was stirred at 700 rpm for 5 minutes with a homodisper stirrer (Polytron PT-3100). It was left at room temperature for one day and filtered through 300 mesh to obtain a water-based paint.

The surface of a 3 mm-thick substrate molded from a polyolefin base material (manufactured by Japan Polypropylene Corporation) "TSOP-6" was wiped with isopropyl alcohol. The obtained water-based paint was spray-coated on the substrate so that the dry film thickness was 20 μm, set at room temperature for 10 minutes, and then dried in an atmosphere of 80° C. for 30 minutes in a Safeven dryer to form a coating film. This was allowed to stand at room temperature for one day to obtain a test piece.

Next, on the coated surface of the test piece, 11 incisions were made at intervals of 1 mm in length and width so as to reach the base material to make 100 grids, and cellophane adhesive tape was pasted thereon, and then the adhesive tape. was rapidly peeled off, the state of the coating film was observed, and the adhesion to the substrate was evaluated according to the following evaluation criteria.
◯: 91 to 100 squares remain in 100 squares.
Δ: 71 to 90 squares remain in 100 squares.
x: Only less than 70 squares remain in 100 squares.

An ABS substrate (UMGABS3001M manufactured by UMGABS Co., Ltd.) and a PC substrate (Panlite L-1225Z-100K manufactured by Teijin Limited) were also evaluated for substrate adhesion in the same manner as described above.

3. Water adhesion resistance (paint preparation)
3 parts by mass of TEGO WET KL-245 (manufactured by EVONIK) was added as a substrate wetting agent to the solid content of the aqueous resin dispersion, and the mixture was stirred at 700 rpm for 5 minutes with a homodisper stirrer (Polytron PT-3100). It was left at room temperature for one day and filtered through 300 mesh to obtain a water-based paint.

The surface of a 3 mm-thick substrate molded from a polypropylene substrate (manufactured by Japan Polypropylene Corporation) "TSOP-6" was wiped with isopropyl alcohol. The obtained water-based paint was spray-coated on the substrate so that the dry film thickness was 20 μm, set at room temperature for 10 minutes, and then dried in an atmosphere of 80° C. for 30 minutes in a Safeven dryer to form a coating film. This was immersed in hot water at 60°C for one day to obtain a test piece.

Next, on the coated surface of the test piece, 11 incisions were made at intervals of 1 mm in length and width so as to reach the base material to make 100 grids, and cellophane adhesive tape was pasted thereon, and then the adhesive tape. was rapidly peeled off, the state of the coating film was observed, and the water adhesion resistance was evaluated according to the following evaluation criteria.
◯: 91 to 100 squares remain in 100 squares.
Δ: 71 to 90 squares remain in 100 squares.
x: Only less than 70 squares remain in 100 squares.
An ABS substrate (UMGABS3001M manufactured by UMGABS Co., Ltd.) and a PC substrate (Panlite L-1225Z-100K manufactured by Teijin Limited) were also evaluated for substrate adhesion in the same manner as described above.

<Production Example 1>
[Production Example 1: Production of maleic anhydride-modified propylene copolymer]
"Tafmer XM-7070" (manufactured by Mitsui Chemicals, Inc., melting point 75°C, propylene content 74 mol%, weight average molecular weight [Mw] 250,000 (polypropylene conversion), molecular weight distribution [Mw / Mn] 2.2) After dry blending 200 kg and 5 kg of maleic anhydride with a super mixer, a twin-screw extruder (“TEX54αII” manufactured by Japan Steel Works, Ltd.) was used to propylene- Kneading while feeding t-butyl peroxyisopropyl monocarbonate (“PERBUTYL I” manufactured by NOF Corporation) with a liquid addition pump so that it becomes 1 part by mass with respect to 100 parts by mass of the butene copolymer. The mixture was kneaded under conditions of a cylinder temperature of 200° C., a screw rotation speed of 125 rpm and a discharge rate of 80 kg/hour to obtain a maleic anhydride-modified propylene-butene copolymer in the form of pellets.
The maleic anhydride group content (graft ratio) of the maleic anhydride-modified propylene-butene copolymer thus obtained was 1.0% by mass (0.1 mmol/g as maleic anhydride group, 0.1 mmol/g as maleic anhydride group, was 0.2 mmol/g). Also, the weight average molecular weight (in terms of polystyrene) [Mw] was 156,000, and the number average molecular weight [Mn] was 84,000.

[Production Example 2: Production of polyolefin resin dispersion]
100 g of the maleic anhydride-modified propylene-butene copolymer obtained in Production Example 1 and 50 g of toluene were placed in a glass flask equipped with a reflux condenser, a thermometer, and a stirrer. °C. After raising the temperature, 2.0 g of maleic anhydride was added, 1 g of t-butyl peroxyisopropyl monocarbonate ("PERBUTYL I" manufactured by NOF Corporation) was added, and the mixture was stirred at the same temperature for 7 hours to carry out the reaction. rice field.
The content (graft ratio) of maleic anhydride groups in the resulting maleic anhydride-modified propylene-butene copolymer was 2.0% by mass (0.2 mmol/g as maleic anhydride groups, 0.4 mmol/g as carboxylic acid groups). / g).
After completion of the reaction, the system was cooled to around room temperature, 70 g of toluene was added, and then 10 g of polyetheramine (trade name “Jefamine M-2005”) dissolved in 90 g of 2-propanol (HLB3, number average molecular weight: 2000, maleic anhydride) was added. (corresponding to 20 parts by mass with respect to 100 parts by mass of the acid-modified propylene-butene copolymer) was added and reacted at 70° C. for 1 hour. After that, 10 g of polyetheramine (trade name “Jeffamine M-1000”) dissolved in 90 g of 2-propanol (HLB17, number average molecular weight of 1000, maleic anhydride-modified propylene-butene copolymer 100 parts by weight) was added to 10 parts by weight. equivalent) and reacted at 70° C. for 1 hour.
Then, 2 g of dimethylethanolamine and 54 g of water were added to neutralize the system. The temperature of the resulting reaction solution was kept at 45° C., heated and stirred, and while 300 g of water was added dropwise, the degree of pressure reduction in the system was lowered until the polymer concentration reached 30% by mass, and toluene and 2-propanol were distilled off under reduced pressure. Then, a milky white aqueous resin dispersion having an average particle size of 70 nm was obtained.

[Production Example 3: Production of polyolefin resin dispersion]
A flask equipped with a stirrer, a reflux condenser, and a temperature controller was charged with 333.3 parts of the aqueous resin dispersion of Production Example 2 as a polyolefin resin dispersion and 119.6 parts of deionized water, and stored at 30°C. .
Next, 10.4 parts of hydroxybutyl acrylate, 44.8 parts of butyl acrylate, and 44.8 parts of isobutyl methacrylate were added as vinyl monomers and stored at 50° C. for 1 hour.
0.02 parts of Perbutyl H69 (manufactured by NOF Corporation) as an initiator, 1.0 parts of deionized water, 0.002 parts of iron sulfate heptahydrate, 0.00027 parts of ethylenediaminetetraacetic acid, erythorbic acid 0.08 part of sodium was added to initiate polymerization.
After detecting the exothermic peak of polymerization, 0.03 parts of Perbutyl H69 and 10.0 parts of deionized water were added dropwise over 15 minutes.
After completion of dropping, aging was performed at 60° C. for 30 minutes to obtain an aqueous resin dispersion having an average particle size of 80 nm.

[Production Example 4: Production method of hydroxyl group-containing resin dispersion]
A polyester-based urethane resin (trade name: Implanil DLP-R, Sumika Covestro Urethane Co., Ltd.) was added as a dispersion of the urethane resin (B1) to a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump. ), solid content 40%): 107 parts (42.8 parts as solid content), deionized water: 32.5 parts, then Neocol SWC (anionic surfactant, Daiichi Kogyo Seiyaku Co., Ltd.) product, solid content 70%): 0.8 parts (solid content 0.56 parts), Adekari Soap ER-10 (nonionic surfactant, manufactured by ADEKA Co., Ltd.): 0.8 parts (solid content 0.56 parts) 8 parts) and a pre-emulsified liquid obtained by previously emulsifying and dispersing n-butyl acrylate: 49.9 parts and allyl methacrylate: 0.1 parts as radically polymerizable monomers, and the flask was heated to 50°C. I warmed up. After that, as a polymerization initiator, Perbutyl H69 (manufactured by NOF Corporation): 0.02 parts (0.013 parts as a pure content), and as a reducing agent, ferrous sulfate: 0.0002 parts, ethylenediaminetetraacetic acid (EDTA): 0.000027 parts, sodium isoascorbate: 0.022 parts, deionized water: 2.0 parts were added. After confirming the peak top temperature due to the heat generated by the polymerization, the internal temperature of the flask was raised to 75° C. and held for 20 minutes.
Next, 2-ethylhexyl acrylate: 13.5 parts, isobutyl methacrylate: 28.6 parts, hydroxyethyl methacrylate: 6.5 parts, and methacrylic acid: 1.4 parts were added to the obtained polymer P dispersion. , Neocol SWC: 0.8 parts (solid content 0.56 parts), Adekaria Soap ER-10: 0.8 parts, deionized water: 30 parts of pre-emulsified pre-emulsified liquid, supersulfic acid An aqueous polymerization initiator solution containing 0.05 parts of sodium hydrogen and 10.0 parts of deionized water was added dropwise over 1 hour. The internal temperature of the flask was maintained at 75° C. during the dropping, and was maintained at 75° C. for 1.5 hours after the completion of the dropping. Thereafter, the reaction solution was cooled to room temperature, and 0.7 parts of 28% aqueous ammonia and 0.7 parts of deionized water were added to obtain a hydroxyl group-containing resin dispersion having an average particle size of 180 nm.

[Production Examples 5 to 9]
A hydroxyl group-containing resin dispersion was obtained in the same manner as in Production Example 4, except that the amount of each monomer in Production Example 4 was changed to that shown in Table 1.

[Production Example 10: Production method of hydroxyl group-containing resin dispersion]
Neocol SWC (anionic surfactant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., solid content 70%): 0.8 parts (solid 0.56 parts per minute), Adekaria Soap ER-10 (nonionic surfactant, manufactured by ADEKA Co., Ltd.): 0.8 parts (0.8 parts in solid content) and acrylic acid as a radically polymerizable monomer A pre-emulsified liquid prepared by previously emulsifying and dispersing 49.9 parts of n-butyl and 0.1 part of allyl methacrylate was charged, and the flask was heated to 50°C. After that, as a polymerization initiator, Perbutyl H69 (manufactured by NOF Corporation): 0.02 parts (0.013 parts as a pure content), and as a reducing agent, ferrous sulfate: 0.0002 parts, ethylenediaminetetraacetic acid (EDTA): 0.000027 parts, sodium isoascorbate: 0.022 parts, deionized water: 2.0 parts were added. After confirming the peak top temperature due to the heat generated by the polymerization, the internal temperature of the flask was raised to 75° C. and held for 20 minutes.
Next, 2-ethylhexyl acrylate: 13.2 parts, isobutyl methacrylate: 28.6 parts, hydroxyethyl methacrylate: 6.5 parts, and methacrylic acid: 1.4 parts were added to the obtained polymer P dispersion. , Neocol SWC: 0.8 parts (solid content 0.56 parts), Adekaria Soap ER-10: 0.8 parts, deionized water: 30 parts of pre-emulsified pre-emulsified liquid, supersulfic acid An aqueous polymerization initiator solution containing 0.05 parts of sodium hydrogen and 10.0 parts of deionized water was added dropwise over 1 hour. The internal temperature of the flask was maintained at 75° C. during the dropping, and was maintained at 75° C. for 1.5 hours after the completion of the dropping. Thereafter, the reaction solution was cooled to room temperature, and 0.7 parts of 28% aqueous ammonia and 0.7 parts of deionized water were added to obtain a hydroxyl group-containing resin dispersion having an average particle size of 180 nm.

[Production Example 11]
A hydroxyl group-containing resin dispersion was obtained in the same manner as in Production Example 10 except that 0 parts of hydroxyethyl methacrylate and 35.3 parts of isobutyl methacrylate were used.

[Example 1]
30 parts of the polyolefin resin dispersion obtained in Production Example 2 as the olefin resin (A) dispersion, and 45.9 parts of the hydroxyl group-containing resin dispersion obtained in Production Example 4 as the hydroxyl group-containing resin (B) dispersion. 3 parts of TEGO WET KL-245 (manufactured by EVONIK) was added as a substrate wetting agent, and the mixture was stirred with a homodisper stirrer (Polytron PT-3100) at 700 rpm for 5 minutes to obtain a water-based coating composition.

[Examples 2 to 8, Comparative Examples 1 to 3]
A water-based coating composition was obtained in the same manner as in Example 1, except that the olefin resin (A) dispersion and the hydrogen group-containing resin (B) dispersion in Example 1 were changed to those shown in Table 2. Examples 5, 7 and 8 are reference examples.

Table 1 shows the charging amounts of the following monomers.
・BA: butyl acrylate ・IBMA: isobutyl methacrylate ・HEMA: hydroxyethyl methacrylate ・EHA: 2-ethylhexyl acrylate ・AMA: allyl methacrylate ・MAA: methacrylic acid

Examples 1 to 8 show excellent initial adhesion to polyolefin substrates, ABS substrates, and PC substrates due to the hydroxyl value of the hydroxyl-containing resin (B) dispersion ranging from 0.1 to 49 mgKOH/g. and water adhesion resistance were obtained.
Among them, Examples 4 and 6 to 8 are particularly excellent for polyolefin bases, ABS bases, and PC bases because the hydroxyl group-containing resin (B) dispersion has a hydroxyl value in the range of 17 to 49 mgKOH/g. Good initial adhesion and waterproof adhesion were obtained.
In Comparative Examples 1 to 3, since the hydroxyl group-containing resin (B) dispersion did not contain hydroxyl groups, the initial adhesion to the polyolefin substrate was poor.

Claims (2)

An olefin resin (A) (excluding chlorinated polyolefin) and a hydroxyl group-containing resin (B) (excluding those corresponding to the olefin resin (A)) in a dispersed state, wherein the hydroxyl group-containing An aqueous coating composition, wherein the resin (B) is a (meth)acrylic urethane composite resin (B2) having a hydroxyl group, and the hydroxyl group-containing resin (B) has a hydroxyl value of 10 to 40 mgKOH/g. 2. The water-based coating composition according to claim 1, wherein the olefinic resin (A) comprises an olefinic composite resin (A3) (excluding a composite resin having a structure derived from chlorinated polyolefin).