JP2649480B2 - Aqueous pigment dispersant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous pigment dispersant. More specifically, it is used for a wide range of water-based paint resins such as aqueous alkyd resin, aqueous melamine alkyd resin, aqueous acrylic resin, aqueous melamine acrylic resin, acrylic emulsion, vinegar emulsion, epoxy emulsion, urethane emulsion, and SBR latex. It relates to possible aqueous pigment dispersants.

[0002]

2. Description of the Related Art Conventionally, paints and inks containing a pigment are prepared by mixing a pigment and a dispersing resin to prepare a pigment dispersion for a primary color paint (pigment masterbatch) and then using the same kind of pigment as that used for the dispersion. It has been commercialized after dilution with resin. This is because when the pigment dispersing resin used for each pigment masterbatch and the resin used for dilution are different from each other, generally, the compatibility between the resins is poor, and the gloss and hardness of the coating film surface are reduced. Therefore, development of a pigment dispersing resin which has excellent compatibility with many kinds of paint resins and can be commonly used for various resin paints has been desired. For this purpose, C 1-7
Using an aqueous product of a copolymer of a (meth) acrylate of a monoalcohol with a nitrogen-containing unsaturated monomer and an α, β-ethylenically unsaturated carboxylic acid (for example, Japanese Patent Publication No. 5-36467). And so on.

[0003]

However, those using the above copolymer can be used for water-dispersed alkyd resins and acrylic emulsions, but have insufficient compatibility with those containing melamine resins. Therefore, there is a problem that the type of resin showing compatibility is limited, and thus it cannot be used for a wide range of aqueous resins.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have found that the present invention has a good compatibility with a very wide range of aqueous resins and, when mixed with each resin, includes the essential properties of each resin including weather resistance and water resistance. As a result of intensive studies on a resin for dispersing an aqueous pigment which does not impair the performance of the above, the present invention has been reached.

That is, the present invention provides an alkyl (meth) acrylate (A) having an alkyl group having 1 to 4 carbon atoms,
Of a long-chain alkyl (meth) acrylate (B) having an alkyl group having 6 to 30 carbon atoms, a copolymer (P) containing the following monomer (C) and hydrophilic monomer (D) as essential constituent units. An aqueous pigment dispersant characterized by comprising an aqueous compound. Monomer (C); (meth) acrylic acid of compound (f) obtained by adding alkylene oxide (e) to compound (d) obtained by reacting styrenes (b) with phenols (a) ester.

In the present invention, the (meth) acrylate (A) having an alkyl group having 1 to 4 carbon atoms includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, 1-propyl (meth) acrylate, isopropyl Examples thereof include (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and a mixture of two or more of these.

Of these, those which increase the glass transition point of the polymer, ie, methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, in order not to lower the hardness of the dried coating film And t-butyl (meth) acrylate are preferred, and methyl methacrylate, t-butyl methacrylate and mixtures thereof are particularly preferred.

Examples of the long-chain alkyl (meth) acrylate (B) having an alkyl group having 6 to 18 carbon atoms include hexyl (meth) acrylate, cyclohexyl (meth) acrylate, and octyl (meth) acrylate. , 2
-Ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, 1 -Methyltridecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate
G, eicosyl (meth) acrylate, docosyl (meth) acrylate, tetracosyl (meth) acrylate
And triacontyl (meth) acrylate and a mixture of two or more thereof.

Of these, hexyl (meth) is required to be compatible with various aqueous resins and not to impair the original performance of each resin including water resistance and weather resistance when mixed with each resin. Acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth)
Acrylates and mixtures thereof are preferred.

The monomer (C) is obtained by reacting a compound (d) obtained by reacting a phenol (a) with a styrene (b),
Compound (f) to which alkylene oxide (e) has been added
(Meth) acrylate.

The phenols (a) include phenol
And alkyl phenol, allyl phenol and aralkyl phenol. The alkyl group generally has 1 to 30, preferably 1 to 8 carbon atoms, and specific examples of the alkylphenol include methylphenol and butylphenol. Examples of the allyl group include a phenyl group, a tolyl group, a xylyl group, a biphenyl group, and a naphthyl group. Specific examples of the allyl phenol include phenyl phenol, biphenyl phenol, and naphthyl phenol. Examples of the aralkyl group include a benzyl group and a phenylethyl group. Specific examples of the aralkyl phenol include benzyl phenol and phenylethyl phenol.
And the like.

[0012] Of these, phenolic resins are required to be well compatible with various water-based resins and not to impair the original performance of each resin, including alcohol resistance and weather resistance, when mixed with each resin. -Methylphenol, phenylphenol and a mixture of two or more thereof are preferred.

The styrenes (a) include styrene, α
Examples include methylstyrene, vinyltoluene, and mixtures of two or more thereof.

The compound (d) is obtained by adding styrenes (b) to phenols (a), and the number of moles of (b) to 1 mole of (a) is usually 0 to 10 moles, preferably 0 to 10 moles. Is 0.3 to 4 mol. (D) can be obtained by subjecting (a) to a Friedel-Crafts reaction with (b). That is, styrenes are added to phenols, and usually A
It is obtained by reacting at a temperature of 110 to 140 ° C. in the presence of an acidic catalyst such as lCl 3, SbCl 5, H 2 SO 4, H 3 PO 4 and activated clay. In (d), in addition to those obtained by adding styrenes to the benzene nucleus of phenols, those obtained by adding styrenes to the benzene nucleus of styrenes once added, and only styrenes are polymerized first, Examples of the polymer include those obtained by adding the benzene nucleus of phenol or the benzene nucleus of styrenes once added.

Examples of the alkylene oxide (e) include ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran. Compound (f) can be prepared by a known method in the form of one or two or more kinds of (e) in any order or in a mixture, that is,
It is obtained by adding under pressure at a temperature of 100 to 190 ° C. in the presence of an alkali catalyst such as NaOH, KOH, Na, CH 3 ONa. The addition mole number of the alkylene oxide (e) to (d) is usually 1 to 10 moles, preferably 1 mole.
４4 mol.

Particularly preferred as (f) is a compound obtained by adding 1 to 4 mol of ethylene oxide to a reaction product of 1 mol of phenol and 1 to 3 mol of styrene.

The monomer (C) is obtained by an esterification reaction or a transesterification reaction of the above (f) with (meth) acrylic acid or alkyl (meth) acrylate. As the method of esterification, known methods, for example, sulfuric acid, a mineral acid such as hydrochloric acid, an organic acid such as aromatic sulfonic acid, a method using a Lewis acid catalyst such as boron fluoride etherate,
A method using an organic metal catalyst such as tetrabutoxytitanium or tin octylate; a method using an acidic ion exchange resin as a catalyst; a method using a drying agent such as anhydrous magnesium sulfate; and a dehydrating agent such as N, N′-dicyclohexylcarbodiimide. Methods and combinations of these methods are included.

The hydrophilic monomer (D) is a compound having a hydrophilic group and a vinyl polymerizable unsaturated group in one molecule.
Carboxylic acid group-containing monomer (D1), sulfonic acid group-containing monomer (D2), hydroxyl group-containing monomer (D3), nitrogen-containing monomer (D4), and a mixture of two or more of these. Can be

Examples of the carboxylic acid group-containing monomer (D1) include (meth) acrylic acid, crotonic acid, itaconic acid, vinylbenzoic acid, (maleic anhydride), maleic acid, fumaric acid and the like, and organic or inorganic bases thereof. Salts, and mixtures of two or more of these.

Examples of the sulfonic acid group-containing monomer (D2) include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylsulfoethyl, and 2- (meth) acrylamide-2-methylpropane. Examples thereof include sulfonic acid, methylallyl sulfosuccinate and the like, and salts thereof with an organic base or an inorganic base, and a mixture of two or more thereof.

Examples of the hydroxyl group-containing monomer (D3) include (meth) allyl alcohol, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycerol (meth) acrylate, polyethylene glycol (meth) acrylate, and vinyl phenol. And mixtures of two or more of these.

Examples of the nitrogen-containing monomer (D4) include:
Vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylcarbazole, vinylpiperidine, (meth)
Acryloylpyrrolidine, (meth) acryloylmorpholine, dimethylaminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, (meth) acrylamide, methyl (meth) acrylamide, methylol (meth) acrylacrylamide, isopropyl (meth) acrylamide dimethylamino Ethyl (meth)
Examples include acrylamide, trimethylamine (meth) acrylimide, and the like, and quaternary salts thereof with an organic compound or an inorganic acid, and a mixture of two or more of these.

Of these, hydrophilic resins are required to be compatible with a variety of aqueous resins in a small amount, and when mixed with each resin, not to impair the original performance of each resin such as water resistance and weather resistance of the coating film. Those having high properties are preferred. Specifically, the carboxylic acid group-containing monomer (D1) and the sulfonic acid group-containing monomer (D
2), a nitrogen-containing monomer (D4) is preferable, and in particular, the carboxylic acid group-containing monomer (D1) is neutralized with a volatile base (ammonia, amine, etc.) to increase the hydrophilicity and make the resin aqueous. When the coating film is dried, it is preferable in that the volatile base is volatilized, the hydrophilicity is reduced, and the water resistance of the coating film is improved.

The copolymer (P) comprises the above (A), (B),
In addition to (C) and (D), if necessary, another polymerizable monomer (E) may be copolymerized.

(E) includes (A), (B) and (C)
There is no particular limitation as long as it can be copolymerized with (A), (B), (C) and (D).
Acrylates [pentyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl (meth)
Acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, allyl methacrylate, dicyclopentenyl (meth) acrylate
, Dicyclopentanyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acryloxyethyl phosphate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, 2-par- Fluorooctylethyl (meth) acrylate, γ- (meth) acryloxypropyltri (trimethylsiloxy) silane, one-terminal (meth) acryloyl group-modified dimethylsiloxane, etc.), vinyl aromatic compounds (styrene, vinyltoluene, α- Methylstyrene, etc.), vinyl chloride, vinyl carboxylate, dienes (such as butadiene and dicyclopentadiene), isoprene and a mixture of two or more of these.

When (E) is used, it is used in an amount of usually not more than 45% by weight, preferably not more than 30% by weight, based on all monomers in the copolymer (P).

The weight ratio of (A) :( B) in the copolymer (P) is usually (30-95) :( 5-70), preferably (45-90) :( 10-55). . If the ratio of (A) is less than 30, the compatibility with an acrylic resin, particularly an acrylic resin containing vinegar biemulsion, will be insufficient. If it exceeds 95, the compatibility with the alkyd resin will be extremely poor.

The weight ratio of (A + B) :( C) is usually (40-98) :( 2-60), preferably (60-9).
5): (5 to 40). When the ratio of (C) is less than 2, the compatibility with the melamine-containing resin becomes insufficient, and
If it exceeds 300, the compatibility with vinegar bi-emulsion and the like becomes extremely poor.

The content of (D) in the copolymer (P) varies depending on the type of (D), but is usually 1 to 40% by weight, preferably 1 to 40% by weight, based on the hydrophilicity of the resin and the water resistance of the coating film. 5-2
5% by weight. If the amount of (D) is less than 1% by weight, the hydrophilicity is too low to make the aqueous solution difficult, and if it exceeds 40% by weight, the water resistance of the coating film may deteriorate.

The hydrophilicity of the resin can be defined by the HLB value of the copolymer (P). The HLB value is, for example,
Teramura, "Synthesis of Surfactant and Its Application" (Maki Shoten 195
It can be calculated from the ratio between the organic value and the inorganic value according to the method described on page 501 (published in 7 years). The HLB value of the copolymer (P) in the present invention is usually 5 to 20, preferably 10 to 15. If the HLB value is less than 5, the hydrophilicity is too low to make water-based, and if it exceeds 20, the water resistance of the coating film may be poor.

The weight average molecular weight of the copolymer (P) determined by gel permeation chromatography (GPC) was as follows:
Usually 1,000 to 100,000, preferably 5,000
0 to 20,000. Weight average molecular weight of 1,000
When the amount is less than 100, the physical properties of the coating film are reduced, and when it exceeds 100,000, the compatibility with various aqueous resins may be reduced.

The method for producing the copolymer (P) of the present invention is not particularly restricted but includes, for example, (A), (B),
It can be produced by polymerizing the monomer mixture comprising (C), (D) and, if necessary, (E) in a bulk or solution state by a known radical polymerization method such as thermal polymerization, photopolymerization or radiation polymerization. A preferred polymerization method is a radical solution polymerization method using a radical initiator in an organic solvent.

In the case of solution polymerization, examples of the organic solvent used include alcohols (methanol, ethanol,
Isopropanol, n-butanol, t-butanol,
n-hexanol, etc.), cellosolve solvents (ethylene glycol, ethyl cellosolve, butyl cellosolve, ethylene glycol monoacetate, methyl cellosolve acetate, etc.), propylene glycol solvents (propylene glycol, propylene glycol monomethyl ether, etc.), carbitol solvents (diethylene glycol) , Methyl carbitol, butyl carbitol, etc.), (di) glyme solvents (ethylene glycol dimethyl ether,
Diethylene glycol dimethyl ether, etc.), ethers (dioxane, tetrahydrofuran, 1,3-dioxolane, etc.), esters (ethyl formate, ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.) Examples include aromatic hydrocarbons (toluene, xylene, etc.), aliphatic hydrocarbons (heptane, mineral spirit, etc.), and mixtures of two or more of these. Among these, preferred solvents are alcohols, esters, ketones alone or a mixture thereof. The use amount of these solvents is usually 10 to 90% by weight based on the weight of the copolymer (P).

When the radical polymerization reaction is carried out, the radical initiator to be used is not particularly limited, and an azo-based initiator (azobisisobutyronitrile, azobisisovaleronitrile, etc.), a peroxide-based compound (t-butylpa −
Oxybenzoate, t-butylperoxyisobutyrate, di-t-butylperoxide, hydrogen peroxide, etc.)
And other polymerization initiators that can be used for ordinary radical polymerization such as sulfides, sulfines, diazo compounds, nitroso compounds, redox systems and ionizing radiation. Preferred among these are azobisisobutyronitrile, t-butyl peroxybenzoate and t-butyl peroxyisobutyrate.

In the production of (P), a known chain transfer agent (lauryl mercaptan, dibenzyl ether, etc.) may be used if necessary.

The polymerization temperature in the production of (P) is usually 50
To 180 ° C., the polymerization time is usually 1 to 20 hours, and the method of polymerization may be either batch or continuous polymerization.

The copolymer (P) thus obtained is usually made aqueous as it is or after distilling off the solvent.
This aqueous conversion can be usually carried out, for example, by neutralizing the carboxyl group in (P) with a known neutralizing agent. Examples of the neutralizing agent in this case include volatile bases [ammonia, amines (ethylamine, butylamine, cyclohexylamine, ethanolamine, diethylamine, dibutylamine, diethanolamine, trimethylamine, triethylamine, tributylamine, triethanolamine, etc.)] And alkali metal compounds (sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, etc.). Of these neutralizing agents, volatile bases are preferred in view of the water resistance of the coating film.

This aqueous solution is usually prepared by suspending or emulsifying the solvent solution of (P), (P), or (P) or the solvent solution of (P) by adding water thereto. Alternatively, it can be carried out by adding an aqueous solution of a neutralizing agent. In this case, the amount of the neutralizing agent to be used is generally 0 to 3 equivalents, preferably 0.5 to 3 equivalents to the carboxyl group in (P).
1.8 equivalents.

The aqueous compound of (P) may contain a solvent. However, if the aqueous resin using the pigment dispersing resin is an emulsion resin, a solvent shock may occur at the time of addition and the emulsion may be destroyed. It is preferable not to contain a solvent. After distilling off the solvent, the solvent can be distilled off and then heated under normal pressure or reduced pressure.

The copolymer (P) in the present invention is particularly excellent in compatibility with an acrylic resin because the main chain skeleton is derived from an acrylic resin, and has a long-chain alkyl group in a side chain, so that it has a melamine-based resin. Especially excellent in compatibility with alkyd resins. That is, the SP whose main chain and side chain are different as a whole
Since it has a well-balanced comb-shaped structure, it has excellent compatibility with various aqueous resins. In addition, it has excellent water resistance and alcohol resistance due to the ubiquitous presence of a plurality of aromatic rings based on the monomer (C) in the side chain, and has a moderate molecular weight. Since deterioration does not occur, it can be used as a pigment dispersing resin for almost all aqueous paints and aqueous ink resins.

The water-based paint and water-based ink resin to be used are not particularly limited, and include known water-soluble resins, water-dispersible resins, and emulsions. Specific examples include, for example, aqueous alkyd resins, melamine alkyd resins,
Water-soluble acrylic resins, melamine acrylic resins, acrylic emulsions, vinegar emulsions, epoxy-based emulsions, urethane-based emulsions, styrene-butadiene-based emulsions, SBR latex, polyolefin-based emulsions, and the like, and mixtures thereof.

The aqueous pigment dispersant of the present invention contains an aqueous component of the copolymer (P) as an essential component, and optionally contains another aqueous resin or another known aqueous additive (surfactant,
Fluidity modifiers, pigment dispersants, adhesion improvers, film-forming auxiliaries, etc.
(A protective colloid) and the like.

A high-concentration pigment dispersion (pigment masterbatch) using the pigment dispersant of the present invention is prepared by mixing the pigment dispersant of the present invention with a pigment and, if necessary, other aqueous resins or various aqueous additives. It is obtained by doing. The pigment concentration in this case differs depending on the type of pigment, but is usually 2 to 2.
70% by weight.

Examples of pigments include inorganic pigments (carbon black, iron oxide, titanium oxide, zinc white, cobalt blue, calcium carbonate, graphite, alumina white, zinc sulfide, vermilion, molybdenum red, clay, ultramarine, navy blue etc),
Organic pigments (nitroso pigments, nitro pigments, azo pigments, phthalocyanine pigments and the like) and mixtures thereof.

The pigment-dispersing resin composition of the present invention or an aqueous pigment masterbatch using the same can be prepared by using a conventional dispersing machine,
For example, it can be obtained by mixing and dispersing in a usual manner using a shaker, a roll mill disperser, a sand grind mill disperser, a planetary mixer, a high speed disperser or the like.

[0046]

EXAMPLES The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. In the examples, "parts" are parts by weight, and "%" is% by weight.

Production Example 1 34 parts of phenol was melted in a flask equipped with a stirrer, a condenser, a thermometer, and a dropping pump, and 3.5 parts of activated clay was added.
The mixture was added dropwise over 3 hours and aged at 110 to 120 ° C for 1 hour. Thereafter, filtration was performed using diatomaceous earth to obtain a styrenated phenol. 82. Styrenated phenol obtained
8 parts were placed in an autoclave equipped with a stirrer, a thermometer and a pressure cylinder, 0.2 parts of potassium hydroxide was added, the temperature was raised to 135 ° C, and 26.4 parts of ethylene oxide were blown into the autoclave.
The reaction was carried out at 35 to 160 ° C. for 3 hours to obtain a styrenated phenol ethylene oxide (2 mol) adduct. 91 parts of the obtained styrenated phenol ethylene oxide (2 mol) adduct is put in a 1-L Erlenmeyer flask, 200 parts of chloroform and 51.5 parts of N, N'-dicyclohexylcarbodiimide are added, dissolved and brought to 2 ° C. After cooling and adding 0.06 parts of dimethylaminopyridine, the liquid temperature was 5 ° C.
21.5 parts of methacrylic acid are gradually added dropwise while maintaining the following. After the completion of the dropwise addition, the mixture was stirred at a liquid temperature of 5 ° C. or lower for 10 hours, and then chloroform was removed to obtain a methacrylic acid ester (C1) of a styrenated phenol ethylene oxide (2 mol) adduct.

Production Example 2 A flask equipped with a stirrer, a condenser, a thermometer and a dropping pump was charged with 61.2 parts of phenylphenol and melted, and 3.5 parts of activated clay was added. 85 parts of α-methylstyrene was added dropwise over 3 hours, and 1
Aged at 10-120 ° C for 1 hour. Thereafter, filtration was performed using diatomaceous earth to obtain α-methylstyrenated phenylphenol. 101.5 parts of the obtained α-methylstyrenated phenylphenol was placed in an autoclave equipped with a stirrer, a thermometer and a pressure-resistant cylinder, and 0.2 parts of potassium hydroxide was added thereto.
The temperature was raised to 35 ° C, 33 parts of ethylene oxide was blown therein, and the mixture was reacted at 135 to 160 ° C for 3 hours to obtain an adduct of α-methylstyrenated phenylphenol ethylene oxide (3 mol). The resulting α-methylstyrenated phenylphenol ethylene oxide (3 mol) adduct 13
Put 4.5 parts in a 1 L Erlenmeyer flask, add 200 parts of chloroform and 51.5 parts of N, N'-dicyclohexylcarbodiimide, dissolve and cool to 2 ° C, and add 0.06 parts of dimethylaminopyridine. Then, 21.5 parts of methacrylic acid are gradually dropped while keeping the liquid temperature at 5 ° C. or lower. After completion of the dropwise addition, the mixture was stirred at a liquid temperature of 5 ° C. or lower for 10 hours, and then chloroform was removed to obtain methacrylic acid ester (C2) of α-methylstyrenated phenylphenol ethylene oxide (3 mol) adduct.

Example 1 A flask equipped with a stirrer, a condenser, a thermometer, an inert gas inlet tube and a dropping pump was charged with n-butanol 100.
And n-butanol was refluxed (temperature; 115-120 ° C.), and while stirring, 40 parts of methyl methacrylate, 10 parts of dodecyl methacrylate, 6 parts of (C1) obtained in Production Example 1 were added. , 20 parts of styrene, 16 parts of methacrylic acid, 8 parts of hydroxyethyl methacrylate, 1 part of dimethylaminoethyl methacrylate and 8 parts of azobisisobutyronitrile were added dropwise over 3 hours. After adding 2 parts of butyronitrile, the mixture was further reacted at the same temperature for 2 hours.
A resin solution having a number average molecular weight of 6,600 (by GPC; the same applies hereinafter) was obtained. This is followed by a 28% aqueous ammonia solution.
After adding 8 parts and 300 parts of water to make the mixture uniform, the solvent was distilled off together with water at 80 ° C. under reduced pressure to obtain a resin solution 1 having a nonvolatile content of 35%.
I got

Example 2 A flask equipped with a stirrer, a condenser, a thermometer, an inert gas inlet tube and a dropping pump was charged with n-butanol 100.
And n-butanol is refluxed (temperature; 115-120 ° C.), and while stirring, 42 parts of methyl methacrylate, 6.5 parts of methyl acrylate, t-
Butyl methacrylate 5 parts, octyl methacrylate 5
Parts, 3 parts of (C2) obtained in Production Example 2, 15 parts of styrene, 15.5 parts of acrylic acid, 7 parts of hydroxyethyl methacrylate, 1 part of diethylaminoethyl methacrylate, and 8 parts of t-butyl peroxybenzoate. Mixture of 3
The mixture was added dropwise over 4 hours, 4 parts of t-butyl peroxybenzoate was added over 1.5 hours, and the mixture was further reacted at the same temperature for 1 hour to obtain a resin solution having a nonvolatile content of 50% and a number average molecular weight of 5,200. Obtained. To this, 28% aqueous ammonia solution10.
8 parts and 300 parts of water were added to make the mixture uniform, and then the solvent was distilled off together with water at 80 ° C. under reduced pressure to obtain a resin solution 2 having a nonvolatile content of 35%.
I got

Example 3 100 parts of methyl isobutyl ketone was put into a flask equipped with a stirrer, a condenser, a thermometer, an inert gas inlet tube and a dropping pump, an inert gas was introduced, and methyl isobutyl ketone was refluxed (temperature; 114-118 ° C), and stirring, 30 parts of methyl methacrylate, methyl acrylate
19.5 parts, octyl methacrylate 10 parts, (C1) 3 parts obtained in Production Example 1, caprolactone-modified 2-hydroxyethyl methacrylate [Placcel FM-2, manufactured by Daicel Chemical Co., Ltd.] 8 parts, anhydrous A mixture of 11 parts of maleic acid, 3 parts of hydroxyethyl acrylate, 1.5 parts of dimethylaminoethyl methacrylate, 11 parts of styrene, 3 parts of cyclohexyl methacrylate and 3 parts of t-butyl peroxoisobutyrate was taken for 3 hours. After completion of the dropwise addition, 2.5 parts of t-butyl peroxyisobutyrate was added over 1.5 hours, and the mixture was further reacted at the same temperature for 1 hour to obtain a nonvolatile matter of 50% and a number average molecular weight of 7,400. A resin solution was obtained. After 12.8 parts of a 28% aqueous ammonia solution and 233 parts of water were added thereto to make the mixture uniform, the solvent was distilled off together with water at 80 ° C. under reduced pressure to obtain a resin liquid 3 having a nonvolatile content of 35%.

Comparative Example 1 A resin solution having a nonvolatile content of 50% and a number average molecular weight of 6,700 was obtained in the same manner as in Example 1 except that styrene was used instead of (C1). 28% of this
After 14.8 parts of an aqueous ammonia solution and 300 parts of water were added to make the mixture uniform, the solvent was distilled off together with water at 80 ° C. under reduced pressure to obtain a resin liquid 4 having a nonvolatile content of 35%.

Comparative Example 2 n-Butanol 100 was added to a flask equipped with a stirrer, a condenser, a thermometer, an inert gas inlet tube and a dropping pump.
And n-butanol was refluxed (115 to 120 ° C.), and 45.2 parts of methyl methacrylate, 41.6 parts of N-vinylpyrrolidone, 13.2 of acrylic acid and azo Bisisobutyronitrile3.
6 parts of the mixture was added dropwise over 3 hours. After the addition was completed, 2.5 parts of azobisisobutyronitrile was added over 1.5 hours, and the mixture was further reacted at the same temperature for 1 hour.
A resin solution having a number average molecular weight of 8,500 was obtained. To this 28
After adding 14.8 parts of aqueous ammonia solution and 300 parts of water to make the mixture uniform, the solvent was distilled off together with water under reduced pressure at 80 ° C.
A resin solution 5 having a nonvolatile content of 35% was obtained.

Performance Test 1 Five types of varnishes for water-based paints shown in Table 1 and resin liquids 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were mixed at a resin solid content weight ratio of 7/3. Then, butyl cellosolve was added as a film-forming aid, and the mixture was applied on a glass plate and dried. Transparent ones (pass), turbid ones ×
(Failed). Table 1 shows the results.

[0055]

[Table 1]

1) Linseed oil fatty acid-modified pentaerythritol / phthalic acid-based alkyd resin having an oil length of 30 and an acid value of 15 was neutralized with 1.0 equivalent of triethylamine to obtain a water-dispersible alkyd varnish having a solid content of 40%. . 2) A mixture of a melamine resin varnish [Cymel 350 manufactured by Mitsui Cyamid Co., Ltd.] and an alkyd varnish having an acid value of pentaerythritol / trimethylolpropane / phthalic acid of 50 and a solid content weight ratio of 2/8 was added with 1.0 equivalent of diethanolamine. A water-soluble melamine alkyd varnish having a solid content of 40% obtained by neutralization. 3) Solid of melamine resin varnish [Cymel 350 manufactured by Mitsui Cyamid Co., Ltd.] and acrylic resin A (copolymer based on monomer composition of 30 parts of methyl methacrylate, 28 parts of butyl acrylate, 22 parts of hydroxyethyl acrylate and 20 parts of acrylic acid) A water-soluble melamine acrylic varnish having a solid content of 40% obtained by neutralizing a mixture having a weight ratio of 2/8 by 1.0 equivalent with diethanolamine. 4) A solid content of 40% obtained by emulsion polymerization of a monomer composition of 29 parts of styrene, 20 parts of methyl methacrylate, 50 parts of butyl acrylate and 1 part of a reactive emulsifier [Eleminol JS-2 manufactured by Sanyo Chemical Industries, Ltd.] Acrylic emulsion. 5) 60 parts of vinyl acetate, 39 parts of methyl methacrylate,
A 40% solids vinegar emulsion obtained by emulsion polymerization of a monomer of 1 part of methacrylic acid and 2 parts of sodium dodecylbenzenesulfonate as an emulsifier.

Performance test 2 A mixture of the acrylic emulsion and vinegar bi-emulsion used in performance test 1 and the resin solutions 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was coated on a glass plate. The surface of the dried coating film was rubbed 20 times with absorbent cotton impregnated with water, and the coating film was visually observed for turbidity. A transparent sample was represented by ○ (pass), and a cloudy one was represented by × (fail). Table 2 shows the results.

[0058]

[Table 2]

Examples 4 to 6, Comparative Examples 3 and 4 Resin liquids 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2
To 20 parts of each, 60 parts of titanium oxide and 40 parts of water were mixed and dispersed by a sand grind mill until the particle size became 10 μm or less.
[5] was prepared.

Performance Test 3 The two varnishes for melamine-based paints (melamine alkyd varnish and melamine acrylic varnish) used in performance test 1 and the pigment master batch [1] obtained in Examples 4 to 6 and Comparative Examples 3 and 4 ] To [5], the resin solid content weight ratio is 8
/ 2 to obtain white paints A1 to A5 from melamine alkyd varnish and white paints B1 to B5 from melamine acrylic varnish. Each white paint is spray-coated on the treated steel sheet so that the dry film thickness becomes 30 μm.
The coating film performance after baking for 20 minutes was evaluated. Table 3 shows the results.
Shown in

[0061]

[Table 3]

1) JIS K-5400 67; 60-degree specular reflectance 2) JIS K-5400 614; use Mitsubishi Uni pencil 3) JIS K-5400 615; Cut 100 squares of 1 mm square and use cellophane tape The number is shown by the number of squares remaining after being pressed and peeled.

[0063]

The aqueous pigment dispersant of the present invention is excellent in pigment dispersibility for various pigments, has good compatibility with various aqueous resins, and exhibits water resistance and weather resistance when mixed with each resin. Since the original performance of each resin coating is not impaired, it is possible to produce a pigment masterbatch that can be used in common for various aqueous resins. Pigment master batches using the pigment dispersant of the present invention include room temperature drying alkyd paints, melamine alkyd paints, melamine acrylic paints, acrylic emulsion paints, acetic acid emulsion paints, epoxy emulsion paints, urethane emulsion paints, SBR latex, etc. It can be used as a colorant in a very wide range of paints and inks, thereby greatly reducing the type of pigment masterbatch and improving paint and ink productivity.

Claims (4)

(57) [Claims] An alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms (A), a long-chain alkyl (meth) acrylate having an alkyl group having 6 to 30 carbon atoms (B), and the following monomers: An aqueous pigment dispersant comprising an aqueous compound of a copolymer (P) containing (C) and a hydrophilic monomer (D) as essential constituent units. Monomer (C); (meth) acrylic acid of compound (f) obtained by adding alkylene oxide (e) to compound (d) obtained by reacting styrenes (b) with phenols (a) ester. 2. The method according to claim 1, wherein (A) :( B) is (30-9%) by weight ratio.
5): (5-70) and (A + B): (C)
The aqueous pigment dispersant according to claim 1, wherein is a weight ratio of (40 to 98): (2 to 60). 3. The weight average molecular weight of (P) is from 1,000 to 1,000.
3. The aqueous pigment dispersant according to claim 1, wherein the amount is 100,000. 4. The aqueous pigment dispersant according to claim 1, wherein the HLB value of (P) is 5 to 20.