JP2002012811A - Method for producing pigment-dispersed resin and water- based pigment dispersion containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based pigment dispersion low in viscosity even in high pigment concentrations and excellent in color developability. SOLUTION: The subject method for producing a pigment-dispersed resin 3,000-50,000 in Mw (weight-average molecular weight) and 10-200 mgKOH/g in resin acid value involves (A) a step wherein methacrylic acid is copolymerized with at least one copolymerizable monomer selected from methacrylic esters and styrene in the presence of a metal complex or addition cleavage-type chain transfer agent as a catalytic chain transfer agent and, ad necessary a radical polymerization initiator to obtain a macromonomer 50-450 mgKOH/g in acid value, and as necessary, a 2nd step wherein the macromonomer is esterified to introduce a polymerizable unsaturated group thereinto and (B) the subsequent step wherein a copolymerization between the above macromonomer into which the polymerizable unsaturated group is introduced optionally and an ethylenically unsaturated monomer is conducted in the presence of a radical polymerization initiator. The other objective pigment dispersion is obtained by the use of the above pigment-dispersed resin. A coating composition is obtained by the use of the above pigment dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pigment-dispersed resin which can be suitably applied to a water-based paint, particularly a water-based topcoat for automotive coating, an aqueous pigment-dispersion containing the pigment-dispersed resin, and an aqueous paint composition. .

[0002]

2. Description of the Related Art Heretofore, as a top coat for automotive coating, a base resin (base polymer) component such as an acrylic resin, a polyester resin, and an alkyd resin having a functional group such as a hydroxyl group and a carboxyl group, an amino resin, Solvent-type ones using a curing agent such as a polyisocyanate compound or an epoxy compound which may be blocked have been widely used.

[0003] In recent years, from the viewpoint of protection of the global environment, paints having a low volatile organic content (VOC) have been demanded. In the field of paints for automotive coatings, in particular, paints for colored base coats have a large amount of discharged VOCs, so that they are strongly required to be water-based. In the future, water-based base coats are expected to become the mainstream rather than solvent-type base coats.

[0004] Problems associated with water-based coloring of base coat paints include, for example, (1) that the pigment-dispersed resin blended in the water-based paint is not compatible with the binder component in the water-based paint; The pigment is not uniformly dispersed by the dispersing resin or the dispersing agent, and the pigment causes aggregation (flocculation or agglomeration). (3) The pigment dispersing resin or the dispersing agent in the aqueous paint is applied without being cured by baking. And deterioration of film performance.

As a pigment dispersing resin (auxiliary agent) for a water-based paint, a polymerizable polymer containing an acidic functional group such as (meth) acrylic acid as described in, for example, JP-A-50-154328, etc. Linear anionic polymers having an acidic functional group obtained by polymerizing a monomer mixture containing an unsaturated monomer as a part of a monomer component are known. Since it has solubility in a medium, it is insufficient in terms of stabilizing the dispersion of the pigment dispersion, and the dispersion has a problem that the viscosity is extremely high and handling becomes difficult.

Further, JP-A-1-182304, JP-A-7-316240, and JP-T-10-502097
As described in Japanese Patent Application Laid-Open Publication No. H10-264, a graft copolymer obtained by copolymerizing a carboxyl group-containing macromonomer is also known. These graft copolymers are excellent in the dispersion stabilization of the pigment dispersion because the trunk portion of the polymer is hydrophobic and the branch portion is hydrophilic, but the viscosity of the pigment dispersion is high. In the future, a pigment dispersion having an even higher pigment concentration is required from the viewpoint of cost and VOC reduction, so that these graft copolymers are never satisfactory.

[0007] At the present time, topcoats for automotive coatings have not only excellent coating properties such as high durability, acid resistance, car wash abrasion resistance and chipping resistance, but also sharpness and transparency more than before. There is a demand for a finished appearance of the coating film such as color development.

An object of the present invention is to provide a method for producing a pigment-dispersed resin capable of overcoming the above-mentioned problems and obtaining an aqueous pigment dispersion having a low viscosity and excellent coloring properties even at a high pigment concentration. To provide. Another object of the present invention is to provide an aqueous pigment dispersion having a low viscosity and excellent color development even at a high pigment concentration. It is a further object of the present invention to provide a water-based paint which is excellent in curability and can form a coating film having excellent finish appearance such as sharpness, transparency, and coloring.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that a specific monomer component can be obtained in the presence of a metal complex as a catalytic chain transfer agent and a radical polymerization initiator. Using a high acid value macromonomer obtained by copolymerizing the above, a pigment dispersion resin obtained by copolymerizing this macromonomer and an ethylenically unsaturated monomer, and an epoxy group-containing polymerizable unsaturated compound to the macromonomer It has been found that the above object can be achieved by using a pigment dispersion resin obtained by copolymerizing a macromonomer obtained by reacting and introducing a polymerizable unsaturated group and an ethylenically unsaturated monomer, thereby completing the present invention. Reached.

That is, the present invention provides: (A) methacrylic acid, at least one selected from methacrylic acid esters and styrene, in the presence of a metal complex or an addition-cleaving type chain transfer agent which is a catalytic chain transfer agent and, if necessary, a radical polymerization initiator. A step of obtaining a macromonomer having a resin acid value of 50 to 450 mgKOH / g by copolymerizing a copolymerizable monomer and (B) copolymerizing the macromonomer with an ethylenically unsaturated monomer in the presence of a radical polymerization initiator Having a weight average molecular weight of 3,000 to 50,000 and a resin acid value of 10 to 200 m
An object of the present invention is to provide a method for producing a pigment dispersion resin in the range of gKOH / g.

Further, the present invention provides: The above (A) step,
(C) a step of introducing a polymerizable unsaturated group into the macromonomer by subjecting the macromonomer obtained in the above step (A) to an esterification reaction with the epoxy group-containing polymerizable unsaturated compound, and (D) a radical polymerization initiator Having a weight average molecular weight of 5,000 to 100,000 and a resin acid value, wherein the macromonomer having the polymerizable unsaturated group introduced therein is copolymerized with an ethylenically unsaturated monomer in the presence of An object of the present invention is to provide a method for producing a pigment dispersion resin in the range of 10 to 200 mgKOH / g.

Further, the present invention provides: The metal complex is a cobalt complex, and the addition cleavage type chain transfer agent is 2,4-
3. The production method according to the above item 1 or 2, wherein the production method is diphenyl-4-methyl-pentene.

[0013] The present invention also relates to 4. The mixing ratio of methacrylic acid, which constitutes the macromonomer obtained in the above step (A), and at least one copolymerizable monomer selected from methacrylic acid esters and styrene, is based on the sum of the two. The method according to any one of the above items 1 to 3, wherein the amount of the copolymerizable monomer is in the range of 8 to 70% by weight and the amount of the copolymerizable monomer is in the range of 30 to 92% by weight.

Further, the present invention provides: An aqueous pigment dispersion containing a pigment dispersing resin, a pigment, an aqueous medium, a basic neutralizing agent and, if necessary, a dispersing aid, produced by the production method according to any one of the above items 1 to 4, is provided. Is what you do. In addition, the present invention provides: It is intended to provide an aqueous coating composition containing the aqueous pigment dispersion according to the above item 5.
Hereinafter, the present invention will be described in detail.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method for producing a pigment-dispersed resin of the present invention will be described. There are two methods for producing the pigment-dispersed resin of the present invention, a first production method and a second production method. First, the first manufacturing method will be described.

The first manufacturing method has the following steps (A) and (B).

Step (A) Step (A) in the first production method of the present invention is carried out in the presence of a metal complex or an addition-cleavable chain transfer agent which is a catalytic chain transfer agent and, if necessary, a radical polymerization initiator. And a step of obtaining a macromonomer by copolymerizing methacrylic acid and at least one copolymerizable monomer selected from methacrylic acid esters and styrene.

When the above-mentioned catalytic chain transfer agent is used,
Catalytic Chain Transfer Polymerization
The copolymerization reaction is carried out by erization (CCTP method).

Regarding the CCTP method, for example,
No. 23209, Japanese Patent Publication No. 7-35411, Japanese Patent Publication No. 9-501457, Japanese Patent Application Laid-Open No. 9-176256, Macromolecules, 1996, 2
9,8083 to 8089 and the like, and in the method of the present invention, these conventionally known CCTP methods can be used. That is, when performing catalytic chain transfer polymerization in the step (A), the polymerizable unsaturated monomer is
Catalytic chain transfer polymerization can be carried out by a method such as a solution polymerization method in an organic solvent or an emulsion polymerization in water in the presence of a metal complex as a catalytic chain transfer agent and a radical polymerization initiator.

The metal complex used in the copolymerization includes, for example, a cobalt complex, an iron complex, a nickel complex,
Examples thereof include a ruthenium complex, a rhodium complex, a palladium complex, a rhenium complex, and an iridium complex. Of these, a cobalt complex is preferable because it efficiently acts as a catalytic chain transfer agent.

Examples of such a cobalt complex include JP-B-6-23209, JP-B-7-35411, US Pat. No. 4,526,945, US Pat.
USP4837326, USP4888661, USP
5324879, WO95 / 17435, Tokiohei 9-5
Known ones described in, for example, Japanese Patent No. 10499 can be used. Specific examples include bis (borondifluorodioxyiminocyclohexane) Co (II), bis (1,2-dioxyiminoethane) Co (II), and bis (borondifluorodimethylglyoxymate) Co (I
I), bis (borondifluorodiphenylguioximate) Co (II), a cobalt (II) chelate of a bicinaliminohydroxyimino compound, a cobalt (II) chelate of a diazadihydroxyiminodialkyldecadiene,
Cobalt (II) chelate of diazadihydroxyiminodialkyldecadiene, cobalt (II) chelate of diazadihydroxyiminodialkylundecadiene, cobalt (II) chelate of tetraazatetraalkylcyclotetradecatetraene, tetraazatetraalkylcyclo A cobalt (II) chelate of tetradodecattraene,
Cobalt (II) chelate of N, N'-bis (salicylidene) ethylenediamine, cobalt (II) chelate of dialkyldiazadioxodialkyldodecadiene, cobalt (II) chelate of dialkyldiazadioxodialkyltridecadiene, cobalt (II) Porphyrin complexes and the like can be mentioned. Of these, bis (borondifluorodimethylglyoxymate) Co (II) and bis (borondifluorodiphenylglyoxymate) Co (II), which are particularly easily available, can be preferably used.

Further, for example, a metal complex described in JP-B-8-19172, in which a radical cleavable group is directly bonded to a metal, can also be used as the metal complex. Examples of the metal include cobalt, rhenium, and iridium, and examples of the group that can undergo radical cleavage include an alkyl group, an aryl group, and a heterocyclic group. In a system using a metal complex in which a radical cleavable group is directly bonded to the metal, a radical polymerization initiator may not be used in combination.

The amount of the metal complex used as the catalytic chain transfer agent is not particularly limited, but is usually methacrylic acid and at least one copolymerizable monomer selected from methacrylic acid esters and styrene. Total amount 100
It is suitable that the amount is usually in the range of 1 × 10 ⁻⁶ to 1 part by weight, preferably 1 × 10 ^{−4 to} 0.5 part by weight, based on part by weight.

A known coordination compound can be added as necessary to adjust the reactivity of the metal complex and improve the solubility. Examples of such coordination compounds include phosphorus compounds such as triphenylphosphine and tributylphosphine; and amine compounds such as pyridine and tributylamine.

As the polymerization initiator usable in the CCTP method, for example, cyclohexanone peroxide, 3,3,3
Ketone peroxides such as 5-trimethylcyclohexanone peroxide and methylcyclohexanone peroxide; 1,1-bis (tert-butylperoxy)-
Peroxyketals such as 3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate; cumene hydropar Hydroperoxides such as oxide and 2,5-dimethylhexane-2,5-dihydroperoxide;
3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-
Butylperoxy) hexane, diisopropylbenzene peroxide, dialkyl peroxides such as tert-butylcumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide and 2,4-dichlorobenzoyl peroxide. Peroxycarbonates such as bis (tert-butylcyclohexyl) peroxydicarbonate; peroxyesters such as tert-butylperoxybenzoate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane Organic peroxide-based polymerization initiators such as 2,2′-azobisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile), azocumene 2,2′-azobismethylvaleronitrile, , 4 ' It can be mentioned azo polymerization initiator such as azobis (4-cyanovaleric acid). The use amount of these radical polymerization initiators is not particularly limited, but usually, the total amount of the copolymerizable monomers is 100.
0.1 to 15 parts by weight, especially 0.3 to 8 parts by weight, based on parts by weight
Desirably it is in the range of parts by weight.

In step (A), when an addition-fragmentation type chain transfer agent is used, a copolymerization reaction is carried out by radical addition-fragmentation type chain transfer polymerization. Examples of the addition-cleavable chain transfer agent include 2,4-diphenyl-4-methyl-1-pentene (abbreviated as “α-methylstyrene dimer”). The amount of the addition-cleavable chain transfer agent is not particularly limited, but is usually based on 100 parts by weight of the total amount of the copolymerizable monomer.
Suitably, it is in the range of 1 to 50 parts by weight, preferably 5 to 30 parts by weight.

In the case of performing the radical addition-fragmentation type chain transfer polymerization in the step (A), the polymerizable unsaturated monomer is dissolved in an organic solvent in the presence of an addition-fragmentation-type chain transfer agent and a radical polymerization initiator. Catalytic chain transfer polymerization can be performed by a method such as a solution polymerization method or an emulsion polymerization method in water. As the radical polymerization initiator, CCT
Those exemplified as the polymerization initiator that can be used in the P method can be similarly used. In the step (A) of the present invention,
A monomer mixture of methacrylic acid and at least one copolymerizable monomer selected from methacrylic acid esters and styrene is copolymerized to obtain a macromonomer. Specific examples of the methacrylic acid ester include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n
-Butyl methacrylate, isobutyl methacrylate,
tert-butyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, tridecyl methacrylate and other C1-24 or cyclic alkyl methacrylate monomers; 2-hydroxyethyl methacrylate, Hydroxypropyl methacrylate,
Hydroxyalkyl methacrylates such as 2,3-dihydroxybutyl methacrylate and 4-hydroxybutyl methacrylate; and monoesters of polyhydric alcohols such as polyethylene glycol monomethacrylate with acrylic acid or methacrylic acid; the above polyhydric alcohols and methacrylic acid A hydroxyl-containing polymerizable unsaturated monomer such as a compound obtained by ring-opening polymerization of ε-caprolactone to a monoesterified product of the following: N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate,
Tertiary aminoalkyl methacrylates such as N, N-dimethylaminopropyl methacrylate; methacrylamide, N, N-dimethylaminoethyl methacrylamide,
N, N-diethylaminoethyl methacrylamide, N,
Methacrylamide such as N-dimethylaminopropyl methacrylamide, N-methylol methacrylamide, N-methylol methacrylamide methyl ether, N-methylol methacrylamide butyl ether or derivatives thereof; 3-ethyl-3-methacryloyloxymethyloxetane, 3-methyl Oxetane ring-containing methacrylates such as -3-methacryloyloxymethyloxetane and 3-butyl-3-methacryloyloxymethyloxetane; methacrylonitrile, vinyl acetate and the like. These polymerizable unsaturated monomers are one kind,
Alternatively, two or more kinds can be used in combination.

The ratio of methacrylic acid to at least one copolymerizable monomer selected from methacrylic acid esters and styrene is such that the resulting macromonomer has an acid value of 50%.
~ 450mgKOH / g, preferably 65 ~ 400mg
KOH / g may be within the range, and based on the total amount of the monomer components, methacrylic acid is usually 8 to 70% by weight, preferably 10 to 60% by weight, and the copolymerizable monomer is 30 to 92% by weight. % By weight, preferably 40 to 90% by weight
Within the range.

In the step (A) of the present invention, examples of the polymerization method for obtaining the macromonomer include a method such as a solution polymerization method in an organic solvent and an emulsion polymerization method in water as described above. However, the solution polymerization method is particularly preferred. The solution polymerization method includes, for example, the above monomer component (methacrylic acid and at least one copolymerizable monomer selected from methacrylic acid ester and styrene), the above-mentioned metal complex which is the catalytic chain transfer agent, or the addition cleavage type. Chain transfer agent, and if necessary, radical polymerization initiator, dissolved or dispersed in an organic solvent,
Usually, a method of heating and copolymerizing at a temperature of about 80 ° C. to 200 ° C. with stirring for about 1 to 10 hours can be exemplified.

Examples of the organic solvent include hydrocarbon solvents such as heptane, toluene, xylene, octane and mineral spirit; ethyl acetate, n-butyl acetate;
Ester solvents such as isobutyl acetate, ethylene glycol monomethyl ether acetate and diethylene glycol monobutyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; methanol, ethanol, isopropanol, n-butanol, sec-butanol, iso- Alcohol solvents such as butanol; ethers such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; swazole 310 manufactured by Cosmo Oil;
Examples thereof include aromatic petroleum solvents such as Swazole 1000 and Swazole 1500. These organic solvents can be used alone or in combination of two or more.
At the time of copolymerization, the organic solvent is used in an amount of usually 400 parts by weight or less based on the total amount of the copolymerized monomer components.

In the above copolymerization reaction, the method of adding the polymerization component and the polymerization initiator is not particularly limited, but the polymerization initiator is divided into several times from the initial polymerization stage to the late polymerization stage rather than being charged all at once in the initial polymerization stage. Separation and dropping are preferred from the viewpoint of controlling the temperature in the polymerization reaction, suppressing the formation of poor crosslinked products such as gelled products, and the like.

The macromonomer thus obtained in step (A) has at least one polymerizable unsaturated bond at one end of its molecule, preferably one polymerizable unsaturated bond, Dispersion stability, pigment dispersibility, viscosity, VO
C, the resin acid value is 50 in terms of the number of colors (coloring degree) of the resin.
~ 450mgKOH / g, preferably 65 ~ 400mg
It is within the range of KOH / g, and the molecular weight is not particularly limited, but usually, the weight average molecular weight is 300 to 1500.
It is preferably in the range of 0, especially 500 to 10,000.

Step (B) In the step (B), an aqueous pigment-dispersed resin is obtained by copolymerizing the macromonomer obtained in the above step (A) and the ethylenically unsaturated monomer in the presence of a radical polymerization initiator. It is a process.

As the above-mentioned radical polymerization initiator, the same one as the radical polymerization initiator optionally used in the step (A) can be used.

As the ethylenically unsaturated monomer copolymerized with the macromonomer, methacrylic acid esters and styrene can be suitably used. As the methacrylic acid ester, the same methacrylic acid ester used in the step (A) can be used. As the ethylenically unsaturated monomer copolymerized with the macromonomer, it is preferable to use at least one monomer selected from methacrylic acid esters and styrene.
Other monomers may be contained in a quantitative ratio of up to% by weight.

Examples of the other monomers include C1 such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate and stearyl acrylate.
Acrylic acid; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate; N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate;
Aminoalkyl acrylates such as N-dimethylaminopropyl methacrylate; acrylamides such as acrylamide, N, N-dimethylaminoethylacrylamide, N, N-diethylaminoethylacrylamide, N-methylolacrylamide methyl ether, N-methylolacrylamide butyl ether and derivatives thereof;
Oxetane ring-containing acrylates such as 3-ethyl-3-acryloyloxymethyloxetane and 3-methyl-3-acryloyloxymethyloxetane; carboxyl group-containing polymerizable unsaturated monomers such as methacrylic acid and acrylic acid; acrylonitrile and vinyl toluene be able to. These monomers can be used alone or in combination of two or more.

Since the resin of the present invention is intended to be used for dispersing an aqueous pigment, the resin structure has a hydrophilic part and a hydrophobic part, and the hydrophobic part functions as a pigment dispersion (adsorption), and the hydrophilic part disperses the aqueous pigment. It is desirable to act as a stabilizer in pastes and waterborne paints.

In the method of the present invention, in synthesizing a block type aqueous pigment dispersion resin in which the structure of the hydrophilic / hydrophobic component is regulated, the macromonomer is the hydrophilic component, and the ethylenically unsaturated monomer to be copolymerized is the hydrophobic component. This is to increase the proportion of the hydrophobic part that acts as a pigment dispersion (adsorption),
This is because it is advantageous to increase the hydrophilic density by using a macromonomer.

Therefore, the ethylenically unsaturated monomer copolymerized with the macromonomer is desirably a hydrophobic monomer, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-
Ethylhexyl methacrylate, n- octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, C _{1 ~} such as tridecyl methacrylate
_24- alkyl or cyclic alkyl methacrylate monomers; styrene, vinyltoluene and the like can be suitably used, and styrene and its derivatives, methyl methacrylate and 2-ethylhexyl methacrylate are particularly preferable.

However, in terms of stabilizing the hydrophobic component in water, a small amount of a hydrophilic polymerizable unsaturated monomer may be copolymerized. Examples of the hydrophilic polymerizable unsaturated monomer include carboxyl group-containing polymerizable unsaturated monomers such as methacrylic acid, methacrylamide, N-methylol methacrylamide, N-methylol methacrylamide methyl ether, N-methylol methacrylamide butyl ether, and the like. (Meth) acrylamide or a derivative thereof.

In the step (B), the copolymerization ratio of the macromonomer and the ethylenically unsaturated monomer is as follows:
5 to 80% by weight of the macromonomer, 20 to 95% by weight of the ethylenically unsaturated monomer, particularly 10% by weight of the macromonomer
~ 60% by weight, 40-90% ethylenically unsaturated monomer
Desirably, it is in the range of weight%.

The pigment-dispersed resin according to the first production method of the present invention obtained through the step (B) has a weight average molecular weight of 3,
000-50,000, especially 5,000-40,000
And the resin acid value is 10 to 200 mgKOH /
g, especially in the range of 20 to 150 mg KOH / g.

Next, a second manufacturing method of the present invention will be described. The second manufacturing method has a step (A), the following steps (C) and (D).

The step (A) in the second manufacturing method is the same as the step (A) in the first manufacturing method.

Step (C) In the step (C), the macromonomer obtained in the step (A) is subjected to an esterification reaction with the epoxy group-containing polymerizable unsaturated compound to form a polymerizable unsaturated group on the macromonomer. This is the step of introducing.

As the epoxy group-containing polymerizable unsaturated compound used herein, glycidyl (meth) acrylate,
Examples thereof include 3,4-epoxycyclohexylmethyl (meth) acrylate and β-methylglycidyl (meth) acrylate, and among them, glycidyl methacrylate is preferable.

In the above esterification reaction, the mixing ratio of the macromonomer and the epoxy group-containing polymerizable unsaturated compound depends on the molecular weight of the obtained pigment-dispersed resin and the remarkable increase in the production of the resin in the next step (D). From the viewpoint of stable production without problems of viscosity and gelation, the amount is preferably 0.5 to 15 parts by weight of the epoxy group-containing polymerizable unsaturated compound, based on 100 parts by weight of the solid content of the macromonomer. Preferably it is 1.0 to 10 parts by weight. By this esterification reaction, the total amount of polymerizable unsaturated groups in the macromonomer was averaged from 0.01 to 3 per molecule,
It is particularly preferable that the number be in the range of 0.05 to 2.5.

In the above esterification reaction, an organic solvent is added to the macromonomer obtained in the step (A), if necessary, usually at a reaction temperature of about 100 ° C. to 150 ° C., and the epoxy group-containing polymerizable It can be performed by reacting with an unsaturated compound. At that time, it is preferable to use a tertiary amine such as N, N-dimethyllaurylamine or N, N-dimethyldodecylamine as a catalyst, and to use a polymerization inhibitor such as 4-t-butylpyrocatechol in combination.

In the step (D), in the presence of a radical polymerization initiator, the macromonomer into which the polymerizable unsaturated group has been introduced and the ethylenically unsaturated monomer are copolymerized to have a weight average molecular weight of 5,000 to 5,000. 100,000, especially 7,000 ~
70,000 and a resin acid value of 10 to 200.
This is a step of obtaining a pigment-dispersed resin within a range of 20 mgKOH / g, particularly 20 to 150 mgKOH / g.

In the step (D), the macromonomer obtained by the esterification reaction in the step (C) is replaced with the macromonomer obtained in the step (A) in the step (B) of the first production method. Is the same as the step (B) except that is used. Since the step (D) is different from the step (B) in that a macromonomer having a polymerizable unsaturated group introduced therein, that is, a so-called polyvinyl macromonomer, is used, the resulting pigment-dispersed resin has a branched structure and also has a high molecular weight. The feature is that it becomes larger.

It is considered that the pigment-dispersed resins obtained by the first production method and the second production method are block-type. However, the spread of the resin in the solvent is small.
Compared to linear (random) type resins and graft type resins,
In particular, it is very advantageous in terms of lowering the viscosity when preparing a pigment paste, and as described above, it is a pigment-dispersing property (color-forming property) because it is a structure-regulating polymer divided into a hydrophobic part and a hydrophilic part. It is very excellent.

The branched pigment-dispersed resin obtained by the second production method is more likely to be branched and made higher in molecular weight than the pigment-dispersed resin obtained by the first production method. The role of the steric repulsion layer for preventing aggregation can be enhanced, which is more advantageous in terms of pigment dispersibility (color-forming properties). On the other hand, when the molecular weight is increased, the viscosity increases, so that the first production method requires Compared to pigment dispersion resin,
It tends to be slightly inferior in terms of increasing the pigment concentration (so-called low VOC).

Next, the aqueous pigment dispersion of the present invention will be described. The pigment dispersion of the present invention contains the pigment dispersion resin, the pigment, the aqueous medium, the basic neutralizing agent, and, if necessary, the pigment dispersant and other additives.

Examples of the above pigments include brilliant pigments such as aluminum powder, copper powder, nickel powder, stainless steel powder, chromium powder, mica-like iron oxide, mica powder coated with titanium oxide, mica powder coated with iron oxide, and brilliant graphite. ; Pink E
B, organic red pigments such as azo and quinacridone, organic blue pigments such as cyanine blue and cyanine green, organic yellow pigments such as benzimidazolone, isoindoline and quinophthalone; titanium white, titanium yellow, Examples include inorganic color pigments such as red iron oxide, carbon black, graphite, iron oxide, and various calcined pigments. The mixing ratio of the pigment is not particularly limited, but is usually 10 to 3,000 parts by weight, based on 100 parts by weight of the pigment-dispersed resin.
It is particularly preferable that the amount is in the range of 15 to 2,000 parts by weight from the viewpoints of pigment dispersibility, dispersion stability, and coloring power of the obtained pigment dispersion.

Examples of the aqueous medium include water and a water-organic solvent mixed solution obtained by dissolving an organic solvent such as a water-soluble organic solvent in water. As an organic solvent,
For example, water-soluble organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, propyl propylene glycol, butyl cellosolve, propylene glycol monomethyl ether, and 3-methyl 3-methoxybutanol; poorly soluble solvents such as xylene, toluene, cyclohexanone, hexane, and pentane; Examples include insoluble organic solvents. The organic solvents can be used alone or in combination of two or more. As the organic solvent, a solvent mainly composed of a water-soluble organic solvent is preferable. The mixing ratio of water and the organic solvent is not particularly limited, but the content of the organic solvent is 5% of the mixed solution.
0 wt% or less, especially 35 wt% or less is desirable. If the ratio is out of this range, there is a possibility that a water-based paint cannot be substantially constituted. The mixing ratio of the aqueous medium is not particularly limited, but usually, based on 100 parts by weight of the pigment dispersion resin,
It is preferably from 50 to 5,000 parts by weight, particularly from 100 to 3,000 parts by weight, from the viewpoints of viscosity at the time of pigment dispersion, pigment dispersibility, dispersion stability and production efficiency.

The basic neutralizing agent functions to neutralize the carboxyl groups in the pigment-dispersed resin and to make the pigment-dispersed resin water-soluble or water-dispersible. Specific examples thereof include ammonium hydroxide. , Sodium hydroxide, inorganic bases such as potassium hydroxide, aminomethyl propanol,
Amines such as aminoethylpropanol, dimethylethanolamine, triethylamine, diethylethanolamine, dimethylaminopropanol and aminomethylpropanol can be mentioned. The compounding amount of the basic neutralizing agent is a quantitative ratio that enables water-solubilization or water-dispersion, and is a ratio where the neutralization equivalent of the carboxyl group in the pigment dispersion resin is usually 0.3 to 1.5. Is preferred.

Examples of the pigment dispersant optionally used include, for example, Disperby manufactured by BYK-Chemie.
k190 and the like, and other additives include an antifoaming agent, a preservative, a rust preventive, and a plasticizer. In consideration of the dispersibility of the pigment and the stability of the paste, any of these compounding amounts may be used for the pigment dispersion resin 100.
It is desirable that the amount be 50 parts by weight or less based on parts by weight.

The above pigment dispersion comprises a binder resin for paint,
And, if necessary, the addition of an aqueous medium, polymer fine particles, a curing catalyst, a basic neutralizing agent, an ultraviolet absorber, an ultraviolet stabilizer, a coating surface regulator, an antioxidant, a fluidity regulator, a silane coupling agent, etc. An aqueous coating composition can be obtained by blending with an agent or the like and stably dispersing in an aqueous medium.

The binder resin for paint includes a base resin and a curing agent which can be used for a water-soluble or water-dispersible paint, such as a hydroxyl group-containing acrylic resin, a hydroxyl group-containing polyester resin, and an epoxy group-containing copolymer resin. ,
Examples of water-based coating resins, such as carboxyl group-containing high acid value resins, amino resins, and polyisocyanate compounds which may be blocked, may be used alone or in combination of two or more. Can be used. The polyisocyanate compound which may be blocked includes both a blocked polyisocyanate compound in which isocyanato groups are blocked and a non-blocked polyisocyanate compound.

As the above-mentioned hydroxyl group-containing acrylic resin, for example, a hydroxyl group-containing polymerizable unsaturated monomer such as 2-hydroxyethyl (meth) acrylate and another polymerizable unsaturated monomer are copolymerized in the presence of a radical polymerization initiator. Weight average molecular weight of about 2,000 to 10 obtained by polymerization
Those having a molecular weight of about 0000, especially 5,000 to 50,000 are preferred.

Examples of the hydroxyl group-containing polyester resin include polyhydric alcohols such as ethylene glycol, butylene glycol, 1,6-hexanediol, trimethylolpropane, and pentaerythritol, adipic acid, isophthalic acid, terephthalic acid, and phthalic anhydride. Acid, hexahydrophthalic anhydride, trimellitic anhydride, and other polyvalent carboxylic acids obtained by a condensation reaction, the weight average molecular weight is about 1,000 to 100,000,
Those having 500 to 70,000 are preferred.

[0062] Examples of the amino resins used as curing agent, melamine resins are common, among them at least a portion of the methylol groups in methylolated melamine resin and methylolated melamine resin etherified with monohydric alcohols of C _{1 ~ 4} The melamine resin is preferably a resin having water solubility or water dispersibility, but a water insoluble resin can also be used.

Commercially available melamine resins include, for example, U-Van 20SE-60 and U-Van 225 (all of which are manufactured by Mitsui Chemicals, trade name), Super Beckamine G
Butyl etherified melamine resins such as 840 and G821 (all of which are manufactured by Dainippon Ink and Chemicals, Inc.); Sumimar M-100, M-40S, and M-55
(These are all manufactured by Sumitomo Chemical Co., Ltd., trade name), Cymel 3
03, 325, 327, 350, and 370 (all, manufactured by Mitsui Cytec Co., Ltd., trade name), Nikarac MS17, MS15 (all, manufactured by Sanwa Chemical Co., trade name), Regin 741 ( Methyl etherified melamine resin such as Monsanto (trade name); Cymel 2
35, 202, 238, 254, 272, 1
A mixed etherified melamine resin of methylation and isobutylation such as 130 (all of which are manufactured by Mitsui Cytec Co., Ltd., trade name) and Sumamil M66B (trade name of Sumitomo Chemical Co., Ltd.); Cymel XV805 (manufactured by Mitsui Cytec Co., Ltd., trade name) Melamine resin mixed with methylation and n-butylation such as Nicarac MS95 (trade name, manufactured by Sanwa Chemical Co., Ltd.).

The polyisocyanate compound which may be used as a curing agent and which may be blocked may be either a polyisocyanate compound having a free isocyanate group or a polyisocyanate compound having a blocked isocyanate group.

Examples of the polyisocyanate compound having a free isocyanate group include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cycloaliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate; Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate; triphenylmethane-4,4 ', 4 "-triisocyanate,
It has three or more isocyanate groups such as 5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene and 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate Organic polyisocyanate itself such as a polyisocyanate compound, or an adduct of each of these organic polyisocyanates with a polyhydric alcohol, a low molecular weight polyester resin or water, or a cyclized polymer of each of the above organic polyisocyanates, May be an isocyanate / biuret compound.

Commercially available polyisocyanate compounds having free isocyanate groups include, for example, Vernock D-750, -800, DN-950, and DN-950.
-970, DN-15-455 (all, manufactured by Dainippon Ink & Chemicals, Inc.), Desmodur L, N, HL, N3390 (all, manufactured by Sumitomo Bayer Urethane Co., trade name), Takenate D-102, -20
2, -110, -123N (all, manufactured by Takeda Pharmaceutical Company, trade name), Coronate EH, L, H
L. and 203 (all, manufactured by Nippon Polyurethane Industry Co., Ltd., trade name), Duranate 24A-90CX (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) and the like.

As the isocyanate group-blocked polyisocyanate compound, the isocyanate group of the above-mentioned polyisocyanate compound having a free isocyanate group may be replaced with a known blocking agent such as oxime, phenol, alcohol, lactam, malonic ester or mercaptan. Blocked by. Examples of these typical commercial products include Vernock D-550
(Manufactured by Dainippon Ink and Chemicals, Inc., trade name), Takenate B
-815-N (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.), Aditol VXL-80 (trade name, manufactured by Hoechst AG, Germany), Coronate 2507 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.), Desmodur N3500 (Sumitomo Bayer) Urethane Co., trade name).

As the aqueous solvent used as required, the same solvents that can be used as the aqueous medium used as needed in producing the pigment dispersion can be used.

The polymer fine particles are polymers which are not dissolved in the coating composition of the present invention and are dispersed as fine particles, and usually those having an average particle diameter in the range of 0.01 to 1 μm are preferable. The polymer particles may or may not be cross-linked inside the particles, but preferably are internally cross-linked. As the polymer fine particles, those known per se as a fluidity modifier for paints in the field of paints can be used.

When the curing agent is a polyisocyanate compound which may be blocked, an organic metal catalyst such as dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate; triethylamine, diethanolamine, etc. When the curing agent is an amino resin such as a melamine resin, a sulfonic acid compound such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, or the like can be used. Amine-neutralized sulfonic acid compounds can be suitably used.

Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, salicylate compounds and oxalic anilide compounds. Examples of the ultraviolet stabilizer include a hindered amine compound.

The aqueous coating composition of the present invention can be used as a coloring coating composition (including a metallic coating and an interference color coating) in which various pigments such as a coloring pigment, a metallic pigment and an interference color pigment are blended. Among them, it can be suitably used as a top coat for automobile coating (colored base coat).

The coating composition of the present invention can be applied to various objects to be coated by a conventional method.
By baking at a temperature of about 10 to 60 minutes, a cured coating film can be formed. In the case of baking for a short time, for example, the maximum material reaching temperature is about 180 ° C. to 250 ° C.
A cured coating film can also be formed by baking for about 20 to 60 seconds under the following conditions.

The object to be coated with the coating composition of the present invention includes:
There is no particular limitation, for example, metal substrates such as steel plate, aluminum, and tin; other substrates such as mortar, cement, plastics, and glass; and surface treatment and / or coating film formation on these substrates. Among them, a metal substrate, in particular, a substrate based on a steel plate, and a substrate based on plastics can be suitably used.

Examples of the steel sheet include cold-rolled steel sheet, hot-dip galvanized steel sheet, electro-galvanized steel sheet, aluminum-plated steel sheet, stainless steel sheet, copper-plated steel sheet, tin-plated steel sheet, lead-tin alloy-plated steel sheet (turn sheet); Zinc alloy-plated steel sheets such as zinc, aluminum-zinc, nickel-zinc and the like can be mentioned. Examples of the steel sheet subjected to the surface treatment include a steel sheet obtained by subjecting the above steel sheet to a chemical conversion treatment such as a phosphate treatment or a chromate treatment.

Further, as the object to be coated with the coating film,
Examples thereof include those in which a substrate is subjected to a surface treatment as necessary and a primer coating film is formed thereon, and those in which an intermediate coating film is formed on the primer coating film.

When the coating composition of the present invention is used as an overcoat for automotive coating, a typical example of the object to be coated is to apply a primer to a chemical conversion-treated steel sheet and to apply an intermediate coating as required. Painted materials, various plastic base materials (subjected to surface treatment, primer coating, intermediate coating, etc. as necessary), and composite members in which these materials are combined are exemplified.

The above-mentioned electrodeposition paint may be either an anionic type or a cationic type, but a cationic type having good anticorrosion is desirable. Known cationic electrodeposition paints can be used. For example, those containing a base resin having a hydroxyl group and a cationic group as a resin component and a curing agent such as a blocked polyisocyanate compound can be suitably used. it can.

The aqueous coating composition of the present invention comprises a composition for forming a colored coating film for one coat and one bake on a substrate, and two coats and one bake (2C1B) on a substrate and two coats and two bake (2C2B) 3 coats 1 bake (3C1B), 3 coats 2 bake (3C2B) or 3 coats 3 bake (3C3
B) It can be suitably used as a top-coating colored base coating composition in a method or the like.

When the coating composition of the present invention is used as a top coating color coating for automobiles, for example, an uncured or cured intermediate coating applied to a primer coating such as an electrodeposition coating or a primer coating On the coating film, for example, by applying a method such as electrostatic atomization coating (bell type), air spray coating, etc., the dried film thickness is usually applied to about 10 to 60 μm, and left at room temperature for several minutes, After forcibly drying for several minutes in the range of about 50 to 80 ° C., apply a clear top coating and apply
By baking at a temperature of about 20 to 180 ° C. for about 10 to 60 minutes, a top-coating colored coating film can be formed. Further, on the uncured or cured topcoat colored coating film coated as described above, a topcoat clear paint is applied by means of, for example, electrostatic atomization coating (bell type or the like), air spray coating, or the like.
An overcoated multilayer coating film can also be formed by coating and curing so that the dry film thickness is usually about 20 to 100 μm.

Examples of the top clear coating composition to be applied on the top coating film include acrylic resins, vinyl resins, polyester resins, and alkyds having a crosslinkable functional group (for example, a hydroxyl group, an epoxy group, a carboxyl group, an alkoxysilane group, etc.). Resin, at least one base resin such as a urethane resin, and an alkyl etherified melamine resin, a urea resin, a guanamine resin, an optionally blocked polyisocyanate compound, an epoxy resin, and a carboxyl resin for crosslinking and curing the base resin. A clear top coating comprising at least one crosslinking agent such as a group-containing compound is suitable, and the mixing ratio of the base resin and the crosslinking agent is usually 50 to 90% by weight based on the total of the two. %,
It is desirable that the crosslinker component is 10 to 50% by weight.

The form of the clear top coating composition is not particularly limited, and may be an organic solvent type, a non-aqueous dispersion type,
Aqueous solution type, aqueous dispersion (slurry) type, high solid type,
Any form such as a powder type can be used.

[0083]

EXAMPLES Hereinafter, the present invention will be further clarified with reference to Production Examples, Examples, and Comparative Examples. Unless otherwise specified, “parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Production of Macromonomer Production Example 1 Methoxypropanol 10 was placed in a normal acrylic resin reaction tank equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser tube.
Five parts were charged and heated and stirred at 105 ° C. while replacing the atmosphere in the reaction vessel with nitrogen. 70 parts of methyl methacrylate, 30 parts of methacrylic acid, 1 part of azobisisobutyronitrile, 5 parts of methoxypropanol, and bis (borondifluorodimethylglyoxymate) CO
(II) A mixture consisting of 0.03 parts was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 105 ° C. for 30 minutes, and then an additional catalyst mixture comprising 10 parts of methoxypropanol and 0.5 part of azobisisobutyronitrile was added dropwise over 1 hour, and then added at 105 ° C. for 1 hour. After aging, the mixture was cooled to obtain a macromonomer (C-1) solution having a solid content of 45%. The resulting macromonomer (C-1) has a resin acid value of about 195 m.
The weight average molecular weight was about 1,800 in gKOH / g.

Production Examples 2 to 4 The same operation as in Production Example 1 was carried out except that the composition was as shown in Table 1 below.
[(C-2), (C-3) and (C-4)] were obtained. Table 1 shows the solid content, resin acid value, and weight average molecular weight of each of the obtained macromonomer solutions. The macromonomer solution obtained in Production Example 4 is for comparison.

[0086]

[Table 1]

Production Example 5 of Polymerizable Unsaturated Group-Introduced Macromonomer The macromonomer (Production Example 1) obtained in Production Example 1 was placed in a usual acrylic resin reaction tank equipped with a stirrer, a thermometer, an air introduction tube, and a reflux cooling tube. C-1) 222.2 parts of the solution and 6.8 parts of methoxypropanol were charged, and the mixture was heated and stirred at 120 ° C. while replacing the air in the reaction vessel. 4 in this
0.05 parts of -t-butylpyrocatechol, 0.1 parts of N, N-dimethylaminoethanol and 5.4 parts of glycidyl methacrylate were added, and reacted at 120 ° C for 2 hours.
A macromonomer (D-1) solution having a polymerizable unsaturated group of 45% solid content was obtained. The resulting macromonomer (D
In -1), the resin acid value was about 175 mgKOH / g, and the weight average molecular weight was about 1,900.

Production Examples 6 to 10 The same procedures as in Production Example 5 were carried out except that the composition shown in Table 2 below was used, and each macromonomer having a polymerizable unsaturated group introduced by an esterification reaction was prepared. solution
[(D-2), (D-3), (D-4), (D-5) and (D-6)] were obtained. Table 2 shows the solid content, resin acid value, and weight average molecular weight of each of the obtained macromonomer solutions.
Each macromonomer solution obtained in Production Examples 9 and 10 is for comparison.

[0089]

[Table 2]

Production Example 1 of Pigment-Dispersed Resin A conventional acrylic resin reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 10 parts of ethylene glycol monobutyl ether, and the macromonomer (D- 1)
The solution was charged with 66.7 parts (30 parts in terms of solid content), heated and stirred, and maintained at 110 ° C. In this, 10 parts of styrene,
30 parts of methyl methacrylate, 20 parts of n-butyl methacrylate, 2-hydroxyethyl methacrylate 10
Of azobisisobutyronitrile and 5 parts of isobutyl alcohol were added dropwise over 3 hours.
After completion of the dropwise addition, the mixture was aged at 110 ° C. for 30 minutes, and then an additional catalyst mixture comprising 10 parts of ethylene glycol monobutyl ether and 0.5 part of azobisisobutyronitrile was added dropwise over 1 hour. Then, the mixture was aged at 110 ° C. for 1 hour and then cooled to obtain a pigment-dispersed resin (A-1) solution having a solid content of 55%. The obtained pigment dispersion resin (A-1) has a resin acid value of about 59 mgKOH / g and a weight average molecular weight of about 7.4.
00.

Examples 2 to 7 and Comparative Examples 1 to 5 The same operation as in Example 1 was carried out except that the composition shown in Table 3 below was used.
-2) to (A-7) and pigment dispersion resin solutions (AC-1) to (AC-5) of Comparative Examples were obtained. The solid content of these pigment dispersion resin solutions, and the resin acid value and weight average molecular weight of the pigment dispersion resin are shown in Table 3 below.

[0092]

[Table 3]

[0093]

[Table 4]

Preparation of Pigment Dispersion Examples 8 to 20 and Comparative Examples 6 to 16 Each of the pigment dispersion resin solutions synthesized in Examples 1 to 7 and Comparative Examples 1 to 5, the pigment and the neutralized amine (N, N- Dimethylaminoethanol) and deionized water, and placed in a 225 cc wide-mouth glass bottle with the composition shown in Table 4 below.
As a dispersion media, glass beads having a diameter of about 1.3 mmφ were added and sealed, and dispersed for 4 hours using a paint shaker to disperse each of the aqueous pigment dispersions (B-1) to (B-13) and (B-13).
C-1) to (BC-11) were obtained.

(Note) in Table 4 has the following meanings. (Note 1) RT355D: Ciba Specialty Chemicals, trade name, organic red pigment. (Note 2) G314: trade name, organic blue pigment manufactured by Sanyo Dyeing Co., Ltd. (Note 3) MT500HD: manufactured by Teica Co., Ltd., trade name,
Inorganic white pigment. (Note 4) Raven5000UIII: trade name, carbon black pigment, manufactured by Columbia Carbon Co., Ltd.

Each of the aqueous pigment dispersions obtained in Examples 8 to 20 and Comparative Examples 6 to 16 was subjected to a performance test according to the following test method. The test results are shown in Table 4 below.

Test Method Coating Appearance: Each pigment-dispersed paste was 100 × 200 mm
Was applied with a bar coater to a dry film thickness of 15 μm and baked at 140 ° C. for 15 minutes. The degree of turbidity of the coating film formed on the film was visually evaluated according to the following criteria. ：: uniform and no turbidity Δ: slight turbidity observed X: considerable turbidity observed

Gloss: The pigment dispersion was applied on a PET film with a doctor blade (4 mil, 100 μm), and the gloss of the dried coating film was measured according to JIS K5400 7.6 (19).
90), the 60 ° specular reflectance of each coating film was measured.

Light transmittance: The pigment dispersion was applied on a PET film with a doctor blade (4 mil, 100 μm),
The light transmittance (%) of the dried coating film was measured using a turbidimeter (COH-3).
00) and the transparency was evaluated by the following formula.

Light transmittance (%) = 100 × [1− (scattered light intensity / irradiation light intensity)] Viscoelastic properties: Viscosity measured by a viscoelasticity analyzer “MR-300” (manufactured by Rheology Co., Ltd.) Seconds (Pa · se
c)] and the yield value (dyn / cm ² ) were measured.

[0101]

[Table 5]

[0102]

[Table 6]

Synthesis Example 1 Ethylene glycol monobutyl ether 40 was added to an acrylic resin reaction tank equipped with a stirrer, thermometer, reflux condenser and the like.
And 30 parts of isobutyl alcohol, and heat and stir until the temperature reaches 100 ° C.
It was dropped over time.

Styrene 20 parts Methyl methacrylate 43 parts n-butyl acrylate 15 parts 2-hydroxyethyl methacrylate 15 parts Acrylic acid 7 parts 2,2′-azobisisobutyronitrile 1 part Isobutyl alcohol 5 parts After dropping, , After holding at 100 ° C. for another 30 minutes,
An additional catalyst solution, which was a mixture of 0.5 part of 2'-azobisisobutyronitrile and 10 parts of ethylene glycol monobutyl ether, was added dropwise over 1 hour. 100 ° C
After stirring for 1 hour, the mixture was cooled, 15 parts of isobutyl alcohol was added, and when the temperature reached 75 ° C., 4 parts of N, N-dimethylaminoethanol was added, and the mixture was stirred for 30 minutes to give an acrylic polymer having a solid content of 50%. A solution (AP-1) was obtained.

Synthesis Example 2 An acrylic polymer having a solid content of 50% was prepared in the same manner as in Synthesis Example 1 except that the composition of the mixture of monomers and the like to be dropped was changed as shown in Table 5 below. Solution (AP-2) was synthesized. Table 5 below shows the characteristic values of the acrylic polymers obtained in Synthesis Examples 1 and 2.

Synthesis Example 3 317.8 parts of isophthalic acid, 196.5 parts of hexahydrophthalic acid, and 372 parts of adipic acid were placed in a reaction vessel equipped with a stirrer, thermometer, rectification tower, nitrogen inlet tube, reflux condenser and the like. .6
Parts, 268 parts of neopentyl glycol, 217.8 parts of 1,6-hexanediol, trimethylolpropane 26
After 3.5 parts were charged and heated and stirred to reach 160 ° C, the temperature was raised to 235 ° C over 3 hours. After aging for 1.5 hours after raising the temperature, the rectification column was switched to a reflux condenser, 100 parts of toluene was introduced, and the reaction was carried out under reflux. 2 as it is
After performing the reaction at 35 ° C. for 6 hours, toluene was removed under reduced pressure, and the mixture was cooled to 170 ° C. and trimellitic anhydride 122.
5 parts were added. After aging at 170 ° C. for 30 minutes, 322 parts of butyl cellosolve was added.
Cooled down. Thereafter, 4 parts of dimethylethanolamine was added, and the mixture was kept at 80 ° C. for 30 minutes. Then 50 ℃
Then, 2600 parts of deionized water was added, and the mixture was stirred for 30 minutes to give a polyester resin (P
P-1) was obtained.

Synthesis Example 4 The same procedure as in Synthesis Example 3 was carried out except that the composition was changed as shown in Table 6 below, and the solid content concentration was changed to 35.
% Of a polyester resin (PP-2). Table 6 below shows resin special values of the polyester resins obtained in Synthesis Examples 3 and 4.

[0108]

[Table 7]

[0109]

[Table 8]

Synthesis Example 5 Synthesis of Acrylic Emulsion 400 parts of deionized water and Newcol 562SF were placed in an acrylic resin reaction tank equipped with a stirrer, thermometer, reflux condenser and the like.
2.4 parts (trade name, manufactured by Nippon Emulsifier Co., Ltd., surfactant) were added, and the mixture was heated and stirred to reach 82 ° C., and then a pre-emulsion preparation mixture was charged. The mixture for preparing a pre-emulsion was composed of 6 parts of styrene and n-butyl acrylate.
5 parts, allyl methacrylate 0.5 parts, Newcol 5
0.175 parts of 62SF and 7.5 parts of deionized water are mixed, and the mixture is dispensed at about 1000 rpm with a disper. For 10 minutes. Twenty minutes after charging the pre-emulsion preparation mixture, 15 parts of deionized water and 0.54 part of potassium persulfate were added. After 10 minutes, while maintaining the temperature at 82 ° C., 114 parts of styrene and 16 parts of n-butyl acrylate
1.5 parts, allyl methacrylate 9.5 parts, Newcol 562SF 3.325 parts and deionized water 142.5
Parts and mixed with a disper at about 1000 rpm. At 10
Stir for 15 minutes and add 15 parts of deionized water and 0.5 parts of potassium persulfate.
The first monomer mixture to which 4 parts were added was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was kept at 82 ° C. for 30 minutes, and then 50 parts of styrene, 23 parts of n-butyl acrylate, 10 parts of 2-hydroxyethyl acrylate, and 5 parts of methacrylic acid
Parts, 1.6 parts of Newcol 562SF and 6 parts of deionized water
0 parts are mixed and about 1000 rpm with a disper. At 1
Stir for 0 minutes and add 15 parts of deionized water and 0.1 ml of potassium persulfate
A second monomer mixture to which 54 parts were added was added dropwise over 1.5 hours. After completion of the dropwise addition, the mixture was kept at 82 ° C. for 30 minutes, cooled, and when the temperature reached 75 ° C., a mixture of 7 parts of N, N-dimethylaminoethanol and 280 parts of deionized water was added dropwise over 15 minutes. After that, the mixture was kept at 75 ° C. for 15 minutes, and then cooled to synthesize an acrylic emulsion having a solid content of 30%.

Production of Colored Paint Composition Example 21 61.3 of the pigment dispersion paste (B-1) obtained in Example 7 was used.
Part (20 parts by solid content), 20 parts of the acrylic polymer solution (AP-1) obtained in Synthesis Example 1 (10 parts by solid content), and the polyester polymer (PP-1) obtained in Synthesis Example 3 57.
1 part (20 parts by solid content), 33.3 parts (30 parts by weight solid content) Cymel 327 (trade name, methyl etherified melamine resin solution of about 90% solid content, manufactured by Mitsui Cytec Co., Ltd.)
Part), and the acrylic emulsion 6 obtained in Synthesis Example 5
6.7 parts (20 parts in solid content) was added, and then "Primal ASE-60" (trade name, Nippon Acrylic Chemical Co., Ltd.)
1% of 28% primer ASE obtained by diluting a thickener) with water to a solid content of 28%, 0.8 part of N, N-dimethylaminoethanol, 230 parts of deionized water and 30 parts of 2-ethylhexyl alcohol was added and the viscosity was 40 seconds (Ford cup # 4/20 ° C), p
A colored coating composition having a H of about 8.5 was obtained.

Examples 22 to 27 and Comparative Examples 17 to 20 Each of the colored coating compositions was obtained in the same manner as in Example 21, except that the composition was as shown in Table 7 below.

Using the colored coating compositions obtained in Examples 21 to 27 and Comparative Examples 17 to 20, each test coated plate was prepared according to the following method for preparing a test coated plate.

Preparation of Test Coated Plate An epoxy resin-based cationic electrodeposition coating was applied on a 0.8 mm thick cold-rolled dull steel plate that had been subjected to zinc phosphate chemical conversion treatment so that the dry film thickness was about 20 μm. On the baked electrodeposition coating film, a polyester resin intermediate coating for automobiles was applied so as to have a dry film thickness of about 20 μm and baked. This coated plate is water-dried with # 400 sandpaper, drained and dried,
Degreasing with petroleum benzine. Then, on the degreased plate, each of the above colored coating compositions whose viscosity was adjusted to about 40 seconds (Ford cup # 4/20 ° C.) was dried at a booth humidity of 70% using a minibell rotating electrostatic coating machine. About 15μ thick
m and left at room temperature for about 5 minutes for setting, and then baked in an electric hot air drier at 80 ° C. for 10 minutes to volatilize most of the volatile components. Thereafter, the temperature of the coating film was returned to room temperature, and an acrylic resin clear paint for automobiles, Magicalon TC71 (manufactured by Kansai Paint Co., Ltd.) was applied to a dry film thickness of 40 μm, and baked at 140 ° C. for 30 minutes using an electric hot air dryer. Thus, each test coated plate was prepared.

Various tests were performed on these test coated plates based on the following test methods. The test results are shown in Table 7 below.
Shown in

Test Method Coating Film Appearance: The finished appearance of the coating film was comprehensively investigated from the glossiness and the feeling of holding, and evaluated according to the following criteria. ：: good, △: bad, ×: extremely poor.

Gloss: JIS K5400 7.6 (19
90), the 60 ° specular reflectance of each coating film was measured.

Brightness: Measured with a sharpness gloss meter PGD-IV manufactured by Japan Color Research Laboratory. The higher the value, the better the sharpness.

Adhesion: JIS K-5400 8.5.
2 (1990) According to the crosscut-tape method, 11 parallel vertical and horizontal straight lines are drawn at 1 mm intervals on the surface of the coating film of the test plate so as to reach the substrate with a cutter knife, and the distance is 1 mm. 100 × 1 mm squares were created. A cellophane adhesive tape was adhered to the surface, and the degree of peeling of the squares when the tape was abruptly peeled was observed and evaluated according to the following criteria. ：: 90 or more squares of the coating film remained, Δ: the coating film was peeled, and the number of remaining squares was 50 or more and 90
Less than, ×: The coating film peeled off, and the number of remaining squares was less than 50.

Acid resistance: 0.5 cc of artificial rain having the following composition was dropped on the coating film of the test plate, heated for 30 minutes on a hot plate heated to 80 ° C., washed with water, and the coated surface was visually observed. Then, the following criteria were used for evaluation. ：: No change was observed on the painted surface, Δ: Whitening and swelling were not observed on the painted surface, but a step was observed at the boundary, ×: Whitening or swelling was observed on the painted surface, 1 mg / g NaNO ₃ aqueous solution 1
9.6 g, 1 mg / g KNO ₃ aqueous solution 5.2 g, 1 m
3.7 g / g CaCl ₂ .2H ₂ O aqueous solution, 1 mg / g
8.2 g of MgSO ₄ .7H ₂ O aqueous solution, 73.3 g of 1 mg / g (NH ₄ ) ₂ SO ₄ aqueous solution, 0.1N H ₂ SO
₄ aqueous solution 30.0 g, 0.1N HNO ₃ aqueous solution 20.0
g, 10.0 g and 1 mg /
g of an aqueous NaF solution (4.7 g), and the pH was adjusted to 1.0 with H ₂ SO ₄ .

Solvent resistance: In a room at 20 ° C., about 1 kg was applied to the painted surface with gauze impregnated with methyl ethyl ketone.
After applying a load of / cm ² and reciprocating 50 times over a length of about 5 cm, the state of the coated surface was visually evaluated according to the following criteria. ：: no change is observed on the coated surface, Δ: scratch is recognized on the coated surface, ×: whitening or swelling of the coated film is recognized.

Impact resistance: JIS K-5400
According to 3.2 (1990) Dupont impact resistance test,
The test was performed with the coating surface of the test coating plate facing upward with a falling weight of 500 g and a tip diameter of the hammer of about 12.7 mm, and the maximum falling weight height at which the coating film was not damaged was indicated. The maximum value is 50 cm.

[0123]

[Table 9]

[0124]

By using the aqueous pigment-dispersed resin of the present invention, it is possible to obtain an aqueous pigment-dispersed paste composition in which the pigment dispersibility, the pigment coloring properties and the let-down stability are greatly improved.

Further, by using the aqueous pigment dispersing resin of the present invention, a coating composition having improved pigment dispersibility can be obtained without impairing the basic coating film performance.

Further, by using the aqueous pigment dispersing resin of the present invention, a pigment paste having a stable and low viscosity can be obtained even when the pigment concentration is increased. Therefore, it is possible to obtain a coating composition which is excellent in the coloring properties of the pigment, the finished appearance of the coating film, and the coating properties such as weather resistance and physical properties, and has a good pigment dispersion stability and a high pigment concentration. it can.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C08F 220/18 C08F 220/18 4J100 290/04 290/04 C09D 5/02 C09D 5/02 157/00 157 / 00 F-term (reference) 4J011 NA12 NA29 NB04 4J015 AA04 AA05 AA06 BA03 BA04 BA06 BA07 BA08 BA10 4J027 AA01 AA02 AJ05 BA05 BA06 BA07 BA08 BA10 BA12 BA13 BA14 CB03 CB09 CC02 CD08 4J037 CC16 CG03 CG03 CG03 CG02 KA08 MA08 MA14 4J100 AB02Q AG04Q AJ02P AL03Q AL04Q AL05Q AL08Q AL09Q AM02Q AM15Q AM19Q AM21Q BA03Q BA08Q BA31Q BC04Q BC08Q BC53Q CA04 CA05 DA29 JA01

Claims (6)

[Claims] 1. A methacrylic acid, a methacrylic acid ester and styrene in the presence of (A) a metal complex or an addition-cleavable chain transfer agent which is a catalytic chain transfer agent and, if necessary, a radical polymerization initiator. And at least one copolymerizable monomer to obtain a resin acid value of 50 to 450 m.
a step of obtaining a macromonomer of gKOH / g and (B) a step of copolymerizing the macromonomer and the ethylenically unsaturated monomer in the presence of a radical polymerization initiator, wherein the weight average molecular weight is 3,000 to 3,000. 50,000
And a resin acid value in the range of 10 to 200 mgKOH / g. 2. The step (A) and the step (C).
Introducing a polymerizable unsaturated group into the macromonomer by subjecting the macromonomer obtained in the above to an esterification reaction with the epoxy group-containing polymerizable unsaturated compound, and (D) the polymerization process in the presence of a radical polymerization initiator. Having a step of copolymerizing a macromonomer having an unsaturated group introduced therein and an ethylenically unsaturated monomer, and having a weight average molecular weight of 5,000.
~ 100,000 and resin acid value 10 ~ 200mgKO
A method for producing a pigment dispersion resin in the range of H / g. 3. The method according to claim 1, wherein the metal complex is a cobalt complex, and the addition-cleavable chain transfer agent is 2,4-diphenyl-4-methyl-pentene.
The manufacturing method as described. 4. The mixing ratio of methacrylic acid and at least one copolymerizable monomer selected from methacrylic acid ester and styrene, which constitutes the macromonomer obtained in the step (A), is based on the total of both. Methacrylic acid is 8 to 70% by weight, and the copolymerizable monomer is 30 to 9% by weight.
4. The composition according to claim 1, wherein the amount is in the range of 2% by weight.
The production method according to any one of the above. 5. A pigment-dispersed resin, a pigment, an aqueous medium, a basic neutralizer and, if necessary, a dispersing aid produced by the production method according to any one of claims 1 to 4. Aqueous pigment dispersion. 6. An aqueous coating composition comprising the aqueous pigment dispersion according to claim 5.