JP2915174B2 - Pigment dispersing resin composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment-dispersing resin composition used for blending a pigment in the production of paints, inks, plastics and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Since pigments generally have poor dispersibility, they have been used by being dispersed in a pigment dispersing resin composition when blended in paints, inks, plastics, and the like. If the dispersion stability of the pigment in the product is poor, the pigment will aggregate and exhibit remarkable thixotropic properties. In the paint prepared using the pigment dispersing resin composition containing the pigment particles thus aggregated, various problems such as a decrease in gloss, a decrease in sharpness, a decrease in coloring power, and color separation occur. In such a resin composition for dispersing pigment, the performance of the pigment cannot be sufficiently exhibited.

[0003] For this purpose, many improvements of resin compositions for dispersing pigments have been conventionally proposed.
-166318, JP-A-61-174939, JP-A-1-141968, JP-A-2-219
866 and the like. The present inventors have also provided a novel pigment dispersing resin composition in, for example, JP-A-61-281161. JP-A-61-281
The pigment dispersing resin composition according to JP-A-161 161 is prepared by using a reaction product of a polyamine and a polyisocyanate as a dispersing agent, and is a useful composition which has considerably solved the above problems.

[0004]

However, in this pigment-dispersing resin composition, when the vehicle resin of the paint to be prepared has a low molecular weight or when the amount of an acidic functional group such as a carboxyl group is small, the dispersion of the resin is difficult. May not be fully satisfactory. In particular, there has recently been a trend toward high solidification (high solid differentiation) of paints due to the demand for solvent removal.
In addition, coating properties such as high weather resistance tend to be highly demanded, but it is necessary to use a low-molecular weight resin with low viscosity as a vehicle resin in order to respond to high solidification. If the amount is too large, the weather resistance and the like deteriorate, so that it is necessary to use a vehicle resin having a small number of acidic functional groups, which makes it difficult to cope with the use of such a vehicle resin.

To cope with this problem, it has been studied to use a resin composition for dispersing a pigment with a resin having a high molecular weight or a resin having a high acid value as a dispersing agent. In order to obtain the effect, it is necessary to increase the compounding amount of this resin, and as a result, it becomes disadvantageous to make the paint high solid, or the paint properties such as weather resistance of the paint are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a low thixotropic property by using a small amount of a pigment without affecting the properties of the coating such as high solids and weather resistance. It is an object of the present invention to provide a pigment-dispersing resin composition capable of stably dispersing a pigment and a method for producing the same.

[0007]

The pigment-dispersing resin composition according to the present invention comprises a polyamine having at least two primary and / or secondary amino groups and a polyisocyanate having at least two isocyanate groups. And a reaction product obtained by reacting a primary and / or secondary amino group with an isocyanate group so that the primary and / or secondary amino groups are at least stoichiometrically equivalent to 1 g of a solid content of an acidic functional group. 0.1 to 2.0 milliequivalents per resin, and the basic amino groups contained in the reaction product of the polyamine and the polyisocyanate are 0.1 to 1 equivalent to the acidic functional group of the resin. It is characterized by being 3.0 equivalents.

In the method for producing a pigment-dispersing resin composition according to the present invention, an acidic functional group is added to the pigment-dispersed resin composition in an amount of 0.1 to 1 g per solid.
In a resin containing 1 to 2.0 meq, a polyamine having at least two primary and / or secondary amino groups and a polyisocyanate having at least two isocyanate groups are combined with an isocyanate group. And primary and / or secondary amino groups are mixed and reacted so that they are at least stoichiometrically equivalent to each other, and a reaction between a polyamine and a polyisocyanate with respect to one equivalent of an acidic functional group of the resin. The basic amino group contained in the product is adjusted to be 0.1 to 3.0 equivalents.

Hereinafter, the present invention will be described in detail. (Resin) The resin used in the present invention has a basic skeleton composed of an ester chain, a vinyl chain, an acrylic chain, an ether chain, or the like, and a part of a hydrogen atom in the molecule is substituted with a halogen atom. May be available. Among them, acrylic resin, polyester resin, and alkyd resin, particularly, acrylic resin and polyester resin are preferable. The molecular weight of this resin is 800 to 20 in number average molecular weight.
It is preferably in the range of 000 (measured by gel permeation chromatography, in terms of polystyrene), more preferably in the range of 1,000 to 10,000 in number average molecular weight. If the molecular weight is less than 800, the effect of enhancing the dispersion stability of the pigment cannot be sufficiently obtained. Conversely, if the molecular weight exceeds 20,000, the viscosity of the pigment dispersing resin composition becomes high, and the high solids of the coating material become high. Is disadvantageous.

As the resin, a resin containing an acidic functional group in an amount of 0.1 to 2.0 milliequivalents per gram of resin solid content is used. The acidic functional group is composed of a carboxyl group, a sulfone group, a phosphoric acid group, and the like, and a resin having a carboxyl group as the acidic functional group is mainly used.
If the content of the acidic functional group is less than 0.1 milliequivalent per gram, the effect of enhancing the dispersion stability of the pigment cannot be sufficiently obtained, and the content of the acidic functional group is not more than 2 per gram.
When the amount exceeds 0 meq, there is a possibility that the coating film properties such as weather resistance of a paint prepared using the resin composition for dispersing a pigment may deteriorate. Here, the acidic functional group (hereinafter, represented by a carboxyl group) may be completely randomly arranged in the resin molecule as in a normal coating resin.
Those in which three carboxyl groups are arranged only at the terminal of the resin molecule, particularly those in which one to three carboxyl groups are arranged only at one end of the resin molecule, are preferable. Advantageously, the carboxyl groups are substantially arranged at one or two specific locations.
In a resin containing a carboxyl group randomly in a molecule, if a large amount of a reaction product of a polyamine and a polyisocyanate is to be contained, the viscosity rise becomes extremely high, and the reaction product is uniformly dispersed in the resin. It may not be present and may precipitate or become turbid. In contrast, a resin in which a carboxyl group is arranged at a specific position in a molecule has a higher polyamine and resin content than a resin containing a carboxyl group at random in a molecule or a resin not containing an acidic functional group such as a carboxyl group. A large amount of a reaction product with the polyisocyanate can be contained, which is advantageous in this respect. In addition, the resin in which the carboxyl group is arranged at a specific position in the molecule is easier to take a dispersion-stabilized structure of the pigment due to solvation when adsorbed on the pigment than the resin which is randomly arranged. It is advantageous. As such a resin, for example, a monool having a number average molecular weight of 800 to 10,000 in a general formula of Q-OH (where Q is an acrylic resin residue or a polyester resin residue), and a cyclic acid anhydride of a carboxylic acid And those obtained by reacting

Next, various methods for synthesizing resins suitable for use in the present invention will be described. <Example 1: Acrylic resin> An acrylic monomer having no carboxyl group was used as an initiator usually used in the synthesis of an acrylic resin, for example, as an azo-nitrile compound,
Initiate polymerization using 2-azo-bis-isobutyronitrile or t-butyl peroxide as a peroxide compound, and use a compound having a carboxyl group as a chain transfer agent, for example, mercaptoacetic acid or mercaptosuccinic acid. Thereby, a carboxyl group can be introduced into the terminal of the acrylic prepolymer.

In addition, when an acrylic resin is synthesized by polymerizing an acrylic monomer not containing a carboxyl group, an initiator containing a carboxyl group, for example, 4,4-
Initiating polymerization with azo-bis- (4-cyanopentanoic acid) can also introduce a carboxyl group into the terminal of the acrylic prepolymer. Furthermore, a carboxyl group can be introduced into the terminal of the acrylic prepolymer also by polymerization of an acrylic monomer using both a chain transfer agent having a carboxyl group and an initiator having a carboxyl group.

Here, the above-mentioned acrylic monomer containing no carboxyl group includes a neutral monomer and a functional group-containing monomer. Examples of the neutral monomer include ethylene, propylene, butadiene, isoprene, chloroprene, vinyl chloride, vinyl acetate, methyl vinyl ether, acrylate (eg, methyl, ethyl, butyl ester), and methacrylate (eg, methyl, ethyl, butyl ester). ), Nitrile derivatives (eg, acrylonitrile, methacrylonitrile, etc.), styrene, styrene derivatives (eg, α-methylstyrene, etc.)
And the like. Also, as a functional group-containing monomer,
Acrylamide, methacrylamide and the like as amide group-containing monomers, and N-
Methoxymethylol acrylamide, N-butoxymethylol acrylamide and the like include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl as a hydroxyl group-containing monomer. Propyl methacrylate, N-methylol acrylamide and the like can be mentioned.

In the polymerization of the acrylic prepolymer (acrylic resin) as described above, a known solution polymerization method is used to prepare the whole amount, a initiator dropping method, or a monomer dropping method at a temperature not lower than the decomposition temperature of the initiator. Is 70-1
The reaction can be carried out at a reaction temperature of 70 ° C. for 1 to 8 hours. <Example 2: Acrylic resin> A neutral acrylic monomer is polymerized by using a chain transfer agent having a hydroxyl group such as mercaptoethanol to prepare an acrylic monol having a hydroxyl group at one end, and further reacted with an acid anhydride. By doing so, a carboxyl group can be introduced into the terminal of the acrylic prepolymer.

As the acid anhydride, phthalic anhydride, tetrahydrophthalic anhydride, tetrachlorophthalic anhydride,
Succinic anhydride, maleic anhydride, trimellitic anhydride,
Examples thereof include cyclic anhydrides of carboxylic acids such as pyromellitic anhydride and benzophenonetetracarboxylic anhydride. <Example 3: Polyester resin> A lactone having 6 to 8 carbon atoms is added to a monohydric alcohol such as butanol or lauryl alcohol, and a ring-opening polymerization reaction is performed to prepare a polyester monol having a hydroxyl group at one end. The reaction is performed at a temperature of 120 to 180 ° C. under a nitrogen atmosphere, and an organic metal catalyst such as tetrabutyl titanate or dibutyltin laurate can be used as a catalyst. By reacting the obtained polyester monool with an acid anhydride, a polyester resin having a carboxyl group at a terminal can be obtained. Examples of the lactone having 6 to 8 carbon atoms include ε-caprolactam, γ-butyrolactone, δ-valerolactone and the like. Examples of the acid anhydride include those listed above.

Example 4: Polyester Resin A polyester resin having a terminal carboxyl group can be obtained by reacting a hydroxycarboxylic acid or a monocarboxylic acid with a lactone having 6 to 8 carbon atoms. The reaction is performed at a temperature of 120 to 180 ° C. under a nitrogen atmosphere, and an organic metal catalyst such as tetrabutyl titanate or dibutyltin laurate can be used as a catalyst. Examples of the hydroxycarboxylic acid include hydroxyacetic acid, hydroxystearic acid, dimethylolpropionic acid, and the like, and examples of the monocarboxylic acid include acetic acid, benzoic acid, octylic acid, lauric acid, and stearic acid. Examples of the lactones and acid anhydrides include those listed above.

Example 5 Polyester Resin A polyester resin having a terminal carboxyl group can be obtained by subjecting a hydroxycarboxylic acid such as 12-hydroxystearic acid to a dehydration polycondensation reaction. The reaction is carried out by using a known esterification catalyst, for example, phosphoric acid, p-toluenesulfonic acid, tetra-n-butyl titanate, dibutyltin oxide, etc., at a temperature of 120 to 200 ° C. to remove generated water out of the system. Can do it.

<Example 6: Polyester resin> Using a monocarboxylic acid as an initiator, a monoepoxy compound and an acid anhydride are reacted at 140 to 160 ° C under a nitrogen atmosphere. As a reaction catalyst, tetra-n-butyl titanate, dibutyltin oxide, dimethylbenzylamine and the like can be used. As the monocarboxylic acid, those listed above can be used, and as the monoepoxy compound, propylene oxide, glycidyl laurate, glycidyl stearate, glycidyl versatate and the like can be used. In this reaction, first, a monocarboxylic acid opens a ring of an epoxy group to form a secondary hydroxyl group, which is reacted with an acid anhydride to form a carboxyl group. A monoepoxy compound further reacts with the carboxyl group to generate an ester bond and a secondary hydroxyl group, and an acid anhydride reacts with the secondary hydroxyl group to generate a carboxyl group. By repeating this, the polyester main chain is extended. If the end of the reaction is terminated by the reaction with the acid anhydride, a polyester resin having a carboxyl group at one end can be obtained.

By the same reaction mechanism, a monoepoxy compound and an acid anhydride are reacted at 140 to 160 ° C. under a nitrogen atmosphere using a monohydric alcohol as an initiator to convert a polyester resin having a carboxyl group at one end. Obtainable. Incidentally, in addition to the resin obtained as in each of the above examples, other acrylic resins, polyester resins, alkyd resins, amino resins typified by melamine-formaldehyde resins, and other resins commonly used in the paint and ink industries. May be mixed and used in combination.

(Polyamine) The polyamine having at least two primary and / or secondary amino groups used in the present invention includes ethylenediamine, 1,3-propylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, Polyalkylene polyamines such as triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine; alicyclic polyamines such as N, N-bis (γ-aminopropyl) piperazine and N- (β-aminoethyl) piperazine; Examples thereof include aromatic polyamines such as bisaminopyridine, xylylenediamine, metaphenylenediamine, and 4,4'-diaminodiphenylmethane. Among these, a polyamine having at least three primary and / or secondary amino groups and a polyamine having at least two primary and / or secondary amino groups and at least one tertiary amino group are preferably used. Can be. In order to improve the dispersibility of the pigment, it is advantageous to increase the density of the functional groups in the resulting dispersant. For this reason, the amine equivalent (molecular weight / total number of 1, 2, and tertiary amino groups) of these polyamines is preferably low, and a polyamine having 100 or less, more preferably 50 or less is advantageous. Examples of suitable polyamines include diethylenetriamine, triethylenetetramine,
Polyethyleneimine industrially obtained by cationic polymerization of tetraethylenepentamine, pentaethylenehexamine, and ethyleneimine, that is, polyalkylenepolyamines such as polyethyleneimine represented by the general formula such as the formula (A), N, N-bis Alicyclic polyamines such as (γ-aminopropyl) piperazine and N- (β-aminoethyl) piperazine; and aromatic polyamines such as bisaminopyridine.

[0021]

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(Polyisocyanate) The polyisocyanate having at least two isocyanate groups used in the present invention includes tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), Xylylene diisocyanate (XD
I), hexamethylene diisocyanate, hydrogenated MD
Illustrative examples include diisocyanate compounds such as I, hydrogenated TDI, hydrogenated XDI, and inholon diisocyanate, and more preferably a polyfunctional polyisocyanate. Examples of such a polyisocyanate include compounds represented by formulas (1) to (4) obtained by reacting a polyol with diisocyanate;
Compounds represented by formula (5) obtained by biuret reaction from diisocyanates, compounds represented by formulas (6) to (8) obtained by ring formation of diisocyanate, and compounds represented by formula (9) ) And the compound represented by the formula (10).

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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The following are examples of trade names of commercial products containing these compounds as main components. That is, those containing a compound of the formula (1) as a main component are "Coronate HL" manufactured by Nippon Polyurethane Industry Co., Ltd., and those containing a compound of the formula (2) as a main component are manufactured by Sumitomo Bayer Urethane Co., Ltd. And a compound containing a compound of the formula (3) as a main component is "Takenate D-1" manufactured by Takeda Pharmaceutical Co., Ltd.
10N ", those having a compound of the formula (4) as a main component are" Takenate D-120N "manufactured by Takeda Pharmaceutical Co., Ltd., and those having a compound of the formula (5) as a main component are manufactured by Takeda Pharmaceutical Co., Ltd. "Takenate D-165N" or "Takenate D
-165N-90CX "," Sumidur N "manufactured by Sumitomo Bayer Urethane Co., Ltd.," Coronate EH "manufactured by Nippon Polyurethane Industry Co., Ltd. The main component is “Desmodur IL” manufactured by Bayer AG, and the main component is the compound “Desmodur HL” manufactured by Bayer AG, and the compound of formula (9) is a main component. "Desmodur R" manufactured by Bayer AG, and "Millionate MR" manufactured by Nippon Polyurethane Industry Co., Ltd. as the main component. These commodities are not pure and are mainly composed of compounds having the structures shown by the respective formulas, and are mixtures with compounds having a structure similar to that structure. It has a number of groups (the number of isocyanate groups per average molecular weight).

(Organic Solvent) The resin composition for pigment dispersion according to the present invention may contain an organic solvent, if necessary. Solvents that can be used as solvents are not particularly limited as long as they are commonly used in the paint and ink industries. For example, toluene, xylene, “Solvesso 100” and “Solvesso 1” manufactured by Esso Standards Co., Ltd.
Hydrocarbon solvents such as 50 "; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ether solvents such as ethylene glycol monoethyl ether and ethylene glycol mononormal butyl ether; -Butanol,
Examples thereof include alcohol solvents such as isobutanol.

These solvents can be used alone or in combination of two or more. By dissolving the above-mentioned resin in these solvents, the production of the pigment-dispersing resin composition according to the present invention can be performed. It can be done easily. The compounding amount of the solvent can be arbitrarily set as required, but it is general to adjust the compounding amount of the solvent so that the solid content in the pigment dispersion resin composition is 5 to 80% by weight. is there. In the production of the pigment dispersion resin composition, a higher proportion of the solvent may be advantageous for the dispersibility of the pigment, but the solvent in the pigment dispersion resin composition is produced after the pigment dispersion resin composition is produced. It can also be adjusted by removing by a method such as concentration under reduced pressure for easy handling.

(Blending ratio of polyamine and polyisocyanate) In the present invention, a polyamine having at least two primary and / or secondary amino groups and a polyamine having at least two
The mixing ratio with the polyisocyanate having two isocyanate groups is preferably set so that the primary and / or secondary amino groups are at least stoichiometrically equivalent to the isocyanate groups, Generally, it is preferable to adjust the compounding ratio so that the amino group is equivalent to or more than the isocyanate group.

When a polyamine having only a primary and / or secondary amino group is used so that the amino group is excessive relative to the isocyanate group, the primary and / or secondary amino group is used.
Alternatively, it is preferable to use a polyamine containing at least three secondary amino groups, and to mix such that at least two amino groups react with the isocyanate group.

When a polyamine having a tertiary amino group in addition to a primary and / or secondary amino group is used, at least two of the primary and / or secondary amino groups react with the isocyanate group. It is preferable to mix them. More preferably, a polyamine containing at least four primary and / or secondary amino groups is used, and a polyisocyanate having an average number of functional groups (ie, isocyanate functional group / average molecular weight) of 2.5 to 6 is used. The polyamine is preferably blended so that at least three amino groups of the polyamine react with the isocyanate group of the polyisocyanate. In each case, the total amount of primary amino groups, secondary amino groups, and tertiary amino groups before the reaction is preferably in the range of 1.05 to 5 times the equivalent of the isocyanate group.

(Blending Ratio of Polyamine and Polyisocyanate to Resin) In the present invention, the blending ratio of polyamine and polyisocyanate to the above resin is such that polyamine and polyisocyanate are equivalent to 1 equivalent of the acidic functional group of the resin. So that the basic amino group contained in the reaction product with the above, that is, the unreacted amino group is stoichiometrically 0.1 to 3.0 equivalents, more preferably 0.2 to 2.0 equivalents. To set. Although the mechanism of pigment dispersion by the pigment dispersion resin composition according to the present invention is not clear, polyurea formed by the reaction of polyamine and polyisocyanate and a resin having an acidic functional group form a huge complex. However, it is considered that this is absorbed by the pigment and contributes to stabilization of the dispersion of the pigment. Therefore, if the amount of the basic amino group contained in the reaction product of the polyamine and the polyisocyanate is less than 0.1 equivalent relative to 1 equivalent of the acidic functional group of the resin, the formation of the complex becomes insufficient. The effect of increasing the dispersion stability of the pigment cannot be sufficiently obtained. Conversely, if the amount of basic amino groups contained in the reaction product of the polyamine and polyisocyanate exceeds 3.0 equivalents per equivalent of the acidic functional groups of the resin, the presence of the basic functional groups becomes excessive. The physical properties of the coating film such as hardness and weather resistance may be adversely affected.

The weight ratio of the polyamine and the polyisocyanate to the resin is such that the weight ratio of the total amount of the polyamine and the polyisocyanate to the resin is 99: 1 to 7
It is preferable that the ratio be in the range of 0:30, more preferably in the range of 97: 3 to 80:20. If the total amount of the polyamine and the polyisocyanate is too large, the viscosity of the pigment dispersing resin composition becomes extremely high, which may cause gelation or insolubilization. It is not preferable because the property becomes insufficient.

(Production of Resin Composition for Dispersing Pigment) The resin composition for dispersing pigment according to the present invention can be produced as follows. That is, first, a resin containing an acidic functional group, a polyamine and an organic solvent are mixed as necessary, and further a polyisocyanate is added, and the polyamine and the polyisocyanate are allowed to react with each other. A resin composition can be obtained. At this time, the polyisocyanate is preferably added with stirring.
Of course, the polyisocyanate may be mixed first, and then the polyamine may be added and reacted. Also, if necessary, in addition to the resin having the acidic functional group,
Other resins, with or without acidic functional groups,
Mixing resins commonly used in the paint and ink industries, such as acrylic resins, polyester resins, alkyd resins, amino resins typified by melamine-formaldehyde resins, and allowing the polyamine to react with the polyisocyanate Can also. The reaction can be carried out at room temperature, but may be carried out by heating as needed. The reaction time is usually within 30 minutes.

(Utilization of Resin Composition for Dispersing Pigment) The resin composition for dispersing pigment according to the present invention produced as described above comprises:
It is used as a pigment dispersant for preparing a pigment dispersion composition by dispersing a pigment, for example, by adding a pigment and a resin composition according to the present invention, and further adding an organic solvent and a vehicle resin as necessary. The pigment dispersion composition can be prepared by stirring and mixing and dispersing the mixture using a disperser. As the disperser, a sand grind mill, a ball mill, a roll mill, an attritor, a dissolver, and the like, which are generally used in the paint industry and the ink industry, can be used. As the vehicle resin, resins commonly used in the paint and ink industries, such as alkyd resins, polyester resins, acrylic resins, polyamide resins, chlorinated polyolefin resins, and polyvinyl acetate resins can be used. The mixing ratio between the pigment and the pigment-dispersing resin composition according to the present invention varies depending on the type of the pigment, but the mixing ratio of the solid content of the pigment-dispersing resin composition to the pigment ranges from 99: 1 to 70:30. Generally preferred.

As the pigment, various inorganic or organic pigments usually used in the paint industry or the printing ink industry can be used. Examples of inorganic pigments include zinc white, titanium oxide, antimony white, red iron oxide, yellow iron oxide, transparent iron oxide, lead red, cadmium yellow, zinc sulfide, lithopone, barium sulfate, lead sulfate, barium carbonate,
Examples of organic pigments include lead white, alumina white, carbon black, and the like. System, flavanthrone system,
Indanthrene, anthrapyrimidine, pyranthrone, isoindolinone, perylene, perinone,
And quinacridone.

[0039]

Next, the present invention will be specifically illustrated by examples. Example 1 A solvent provided in column (a) of Table 1 was charged into a reaction vessel equipped with a cooling pipe, a stirrer, a nitrogen introduction pipe, and a dropping funnel, and heated to 130 ° C. under a nitrogen stream. Next, using a dropping funnel, (a) in Table 1 was used.
The monomers in the column were dropped at a constant rate over 3 hours, and at the same time, the initiator solution and the chain transfer agent solution in the column (a) of Table 1 were mixed and dropped at a constant rate using another dropping funnel. Thirty minutes after the completion of the dropping, the post-addition solution of column (a) in Table 1 was dropped at a constant speed over 30 minutes to complete the polymerization. After 1 hour, the mixture was cooled and taken out of the reaction solution to obtain a resin solution (a) having an acidic functional group (carboxyl group) at a molecular terminal and having a solid content of about 50%.

The solid content of this resin solution, the amount of acidic functional groups in the resin solid content, and the number average molecular weight were measured. The solid content was measured by heating and drying the resin solution at 110 ° C. for 3 hours, and the results are shown in Table 2 by weight%. The amount of the acidic functional group in the resin solid content was measured by titration with potassium hydroxide using phenolphthalein as an indicator. The results are shown in Table 2 in terms of the acid value (mgKOH /
g). The measurement of the number average molecular weight was performed by gel permeation chromatography.

Next, methylisobutylketone as a solvent and tetraethylenepentamine as a polyamine were added to the resin solution (a) prepared as described above in the amounts indicated in Table 3 and stirred. Taketake D-165N manufactured by Takeda Pharmaceutical Company Limited as a polyisocyanate while stirring.
"-90CX" (amine equivalent: 200) was added in the amount shown in Table 3, and the mixture was further stirred to obtain a pigment-dispersing resin composition (a-1) (a-2) (a-3).

The solid content of the pigment-dispersing resin composition thus obtained was measured by heating at 110 ° C. for 3 hours and drying, and the state of the pigment-dispersing resin composition was observed. Further, the amount (B) of the amino group contained in the reaction product of the polyamine and the polyisocyanate and the amount (A) of the carboxyl group in the solid content of the pigment-dispersing resin composition were measured, and the ratio between the two was calculated as the equivalent ratio. (B / A). Here, the measurement of the amount of amino group was performed by dissolving the pigment-dispersed resin composition in acetic acid and then titrating with perchloric acid.
The end point was determined by potentiometric titration. These results are
It is shown in the table.

Example 2 In the same manner as in Example 1, the composition shown in the column (b) of Table 1 was used.
A resin solution (b) having an acidic functional group (carboxyl group) at the molecular terminal and having a solid content of about 50% was obtained. Using this resin solution (b), a polyamine or polyisocyanate was added in the composition shown in Table 3 and reacted in the same manner as in Example 1 to obtain a pigment-dispersing resin composition (b-1) (b −
2) (b-3) was obtained.

Example 3 In the same manner as in Example 1 except that the heating temperature was changed to 100 ° C., the solid content having an acidic functional group (carboxyl group) at the molecular terminal was prepared in the composition shown in column (c) of Table 1. About 50% resin solution (c) was obtained. Using this resin solution (c), a polyamine or polyisocyanate was added in the composition shown in Table 3 and reacted in the same manner as in Example 1 to obtain a pigment-dispersing resin composition (c-1) (c -2) (c-3) was obtained.

Example 4 In the same manner as in Example 1, the composition shown in column (d) of Table 1 was used.
A resin solution (d) having a solid content of about 50% and having an acidic functional group (carboxyl group) randomly in the molecule was obtained. Using this resin solution (d), a polyamine or polyisocyanate was added in the composition shown in Table 3 and reacted in the same manner as in Example 1 to obtain a pigment-dispersing resin composition (d-1).
(D-2) (d-3) was obtained.

Example 5 In the same manner as in Example 1, the composition shown in column (e) of Table 1 was used.
A resin solution (e) having a solid content of about 50% and having an acidic functional group (carboxyl group) in the molecule at random was obtained. By using this resin solution (e) and adding and reacting a polyamine or polyisocyanate with the composition shown in Table 3 in the same manner as in Example 1, the pigment-dispersing resin composition (e-1)
(E-2) (e-3) was obtained.

Among the above Examples 1 to 5, those of Examples 4 and 5 in which a resin having an acidic functional group at random in the molecule is used, the resin composition for pigment dispersion (d -2) As in (d-3) and the pigment dispersing resin compositions (e-2) and (e-3) in Example 5, those having high viscosity to form paste or gel are also used. It is confirmed that it is preferable to use a resin having an acidic functional group at a molecular terminal as in Examples 1 to 3 in order to obtain a stable pigment dispersion resin composition.

COMPARATIVE EXAMPLE 1 The resin solution (c) obtained in Example 3 was used, and after that, in the same manner as in Example 1, the reaction was carried out with or without the addition of polyamine or polyisocyanate in the formulation shown in Table 4. Thus, a pigment-dispersing resin composition (c-4) (c-5) was obtained. Comparative Example 2 In the same manner as in Example 1, a resin solution (f) was obtained with the composition shown in the column (f) of Table 1. Using this resin solution (f), a polyamine or polyisocyanate was added in the composition shown in Table 4 and reacted in the same manner as in Example 1 to obtain a pigment-dispersing resin composition (f-1) (f -2) (f-3) was obtained. (F-2) and (f-3) had extremely high viscosities and could not be used as dispersants.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

[0055]

[Table 7]

(Preparation of paint) 50 parts by weight of resin solution (f), 30 parts by weight of xylene, 20 parts by weight of "Shinkasha Red Y" manufactured by Ciba-Geigy as a pigment, and a resin composition (a- 3) (b-3) (c-1)
(C-2) (c-3) (d-1) (e-1) and (c-
4) (c-5) (f-1) was added in an amount of 0 to 30% by weight (in terms of solid content) with respect to the pigment, and dispersed by stirring for 1 hour with a paint shaker. After dispersing the pigment in this manner, 20 parts by weight of the resin solution (f) and 20 parts by weight of a melamine formaldehyde resin varnish “Uvan 20N-60 Varnish” manufactured by Mitsui Toatsu Chemicals Co., Ltd. The paint was prepared by adding thinner to seconds.

This paint was spray-coated on a tin plate and baked at 130 ° C. for 20 minutes to obtain a coating film. FIG. 1 shows the relationship between the 20 ° specular gloss of the coating film thus obtained and the amount of the resin composition for pigment dispersion added. Pigment dispersion resin composition (a-3) (b-3) (c-1) (c) obtained in each example
By blending (2), (c-3), (d-1) and (e-1), it is confirmed that the gloss of the coating film can be increased and the dispersibility of the pigment is improved. On the contrary,
(C-4) In the case of (f-1), the gloss of the coating film could not be increased, and the dispersibility of the pigment was not improved. The hardness of the coating film obtained as described above was measured by pencil hardness. The pigment-dispersing resin composition (a) obtained in each Example
-3) (b-3) (c-1) (c-2) (c-3) (d
-1) Compounds containing (e-1) were all "F" regardless of the amount used, which was the same as the case without compounding.
On the other hand, the use of the pigment-dispersing resin composition (c-5) can enhance the gloss of the coating film. However, this resin contains a large amount of amino groups and therefore has a solid content of 10% with respect to the pigment.
When used in an amount of not less than% by weight, the hardness of the coating film decreased from "F" to "B" in pencil hardness.

Example 6 A reaction vessel was charged with 74 parts by weight of n-butanol, 2000 parts by weight of ε-caprolactone “Placcel M” manufactured by Daicel Chemical Industries, Ltd. and 4 parts by weight of dibutyltin oxide, and reacted at 150 ° C. under a nitrogen atmosphere. To prepare a polyester resin having a hydroxyl group at a terminal, and to obtain a solid content of 50%.
The resin solution (g) was obtained by dissolving xylene in a weight%.

By reacting 100 parts by weight of this polyester resin solution (g) with 3.6 parts by weight of phthalic anhydride at 120 ° C. for 2 hours, a resin having an acidic functional group (carboxyl group) at a molecular terminal was obtained. Then, 4.0 parts by weight of pentaethylenehexamine as a polyamine and "Takenate D-165N-90CX" (amine equivalent: 200) 1 manufactured by Takeda Pharmaceutical Co., Ltd. as a polyisocyanate were added.
2.0 parts by weight were added and reacted by stirring, and the solid content was adjusted to 50% with xylene to obtain a pigment-dispersing resin composition (g-1).

The above polyester resin solution (g) 10
0 parts by weight and 7.3 parts by weight of trimellitic anhydride at 120 ° C.
For 2 hours to obtain a resin having an acidic functional group (carboxyl group) at the molecular terminal. Then, 4.0 parts by weight of pentaethylenehexamine as a polyamine and 12.0 of “Takenate D-165N-90CX” manufactured by Takeda Pharmaceutical Co., Ltd. as a polyisocyanate.
Add the parts by weight and react with stirring. Solid content 50% with xylene
To obtain a pigment-dispersing resin composition (g-2).

Example 7 A 50% xylene solution of "Placcel 220L" manufactured by Daicel Chemical Industries, Ltd. was used as a polyester resin having hydroxyl groups at both ends of the molecule. 0.4 parts by weight,
For 2 hours to obtain a resin having an acidic functional group (carboxyl group) at both ends of the molecule. Pentaethylenehexamine as a polyamine;
0 parts by weight, "Takenate D-165N-90CX" 1 manufactured by Takeda Pharmaceutical Company Limited as a polyisocyanate
2.0 parts by weight were added and reacted by stirring, and the solid content was adjusted to 50% with xylene to obtain a pigment-dispersing resin composition (h).

(Preparation of pigment dispersion composition) Pigment "Chromo Fine Magenta 6880" manufactured by Dainichi Seika Kogyo Co., Ltd. 20
The resin composition for pigment dispersion (g-1) (g-2) is used in parts by weight.
(H) was added in an amount of 1 to 20 parts by weight in terms of solid content, and xylene was blended to make up to 100 parts by weight, which was dispersed for 1 hour using a paint shaker to obtain a paste-like pigment dispersion composition.

The viscosity of this pigment dispersion composition was measured at a shear rate of 19.2 / sec and a temperature of 20 ° C. using a cone plate type rotary viscometer (E-type viscometer manufactured by Tokyo Keiki Co., Ltd.). FIG. 2 shows the relationship between the amount of the resin composition for pigment dispersion and the viscosity. It is confirmed that the pigment dispersing resin compositions obtained in Examples 6 and 7 can reduce the thixotropy of the pigment dispersing composition and reduce the viscosity with a small amount of addition, thereby obtaining excellent fluidity. In particular, the pigment-dispersing resin compositions (g-1) and (g-2) were excellent.

A paste-like pigment dispersion composition was similarly obtained using the resin solution (g) as it was. The viscosity was measured in the same manner as for this, and the relationship between the amount added and the viscosity was shown in FIG. It is confirmed that even if the resin solution (g) is used as it is, there is no effect of lowering the thixotropic property of the pigment dispersion composition.

[0065]

As described above, the pigment-dispersing resin composition according to the present invention can stably disperse a pigment with a small amount of thixotropic property by using a small amount thereof. It does not affect the properties of the coating such as the properties.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of a pigment-dispersing resin composition and the gloss of a coating film.

FIG. 2 is a graph showing the relationship between the amount of a pigment dispersion resin composition added and the viscosity of the pigment dispersion composition.

Claims (5)

(57) [Claims] 1. A polyamine having at least two primary and / or secondary amino groups and a polyisocyanate having at least two isocyanate groups, which are primary and / or secondary relative to the isocyanate group. A reaction product obtained by reacting the amino groups in stoichiometric amounts to be at least equivalent, and a resin containing 0.1 to 2.0 milliequivalents of acidic functional groups per gram of solid content. A resin composition for dispersing a pigment, wherein a basic amino group contained in a reaction product of the polyamine and the polyisocyanate is 0.1 to 3.0 equivalents with respect to 1 equivalent of an acidic functional group of the resin. Stuff. 2. The pigment dispersing resin composition according to claim 1, wherein the resin is selected from an acrylic resin, a polyester resin, and an alkyd resin, and has a number average molecular weight of 800 to 20,000. 3. The pigment-dispersing resin composition according to claim 1, wherein the resin has one to three carboxyl groups as an acidic functional group at the terminal of the molecule. 4. The pigment-dispersing resin composition according to claim 1, wherein the resin has one to three carboxyl groups as an acidic functional group at one end of the molecule. 5. The method of claim 1 wherein the acidic functional groups are present in an amount of 0.1 g / g solids.
In a resin containing 1 to 2.0 milliequivalents, a polyamine having at least two primary and / or secondary amino groups and a polyisocyanate having at least two isocyanate groups are converted to an isocyanate group. On the other hand, primary and / or secondary amino groups are mixed and reacted so that they are at least stoichiometrically equivalent, and the reaction product of polyamine and polyisocyanate with respect to one equivalent of the acidic functional group of the resin. The method for producing a pigment-dispersing resin composition, wherein the basic amino group contained in the resin composition is adjusted to be 0.1 to 3.0 equivalents.