JPH01236930A - Dispersant and the dispersant-containing dispersion - Google Patents

Abstract

PURPOSE:To prevent cohesion of pigments at high concn., by preparing a dispersant of a reaction product of a carboxyl-contg. alkali soluble styrene- acrylic copolymer with a poly(ethylene)imine. CONSTITUTION:A dispersant is prepd. from reaction products of carboxyl-contg. alkali soluble styrene-acrylic copolymer, a compound (I); HO(CH2CH2O)n R; (R is alkyl, alkylphenyl; n is 2-20 integer), a carboxyl-contg. ester prepd. by dehydration in excess carboxyl ratio to hydroxy, and a poly(ethylene)imine. A fine powder solid, a dispersing solvent of an organic liquid, and the above- mentioned resulting dispersant are mixed to give a dispersion. The dispersant is useful as, for example, a pigment dispersing dispersant.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to dispersing fine powder solids such as inorganic or organic pigments in an organic liquid, and of course when the organic liquid is polar. It is a dispersant that can impart excellent fluidity and dispersion stability to the dispersion system even when it is a non-polar system, and can be used in general coating compositions such as printing inks and paints. More specifically, it relates to a dispersant that has a high concentration, low viscosity, is stable over time, and can provide a pigment dispersion for coating that has satisfactory performance with a small amount of use, and the dispersant. By containing K, it is intended to provide a dispersion liquid having excellent fluidity and dispersion stability.

[Conventional technology]

In general, useful pigments that can exhibit high tinting power, excellent gloss, and vivid color tones in color material compositions for various applications such as printing inks and paints are composed of fine solid particles. ing.

However, fine particles, such as the various known pigments, when dispersed in non-polar organic solvents containing vehicle polymers, such as in offset inks, gravure inks, flexographic inks and paints, especially at high pigment concentrations, It is difficult to obtain a coloring material composition with excellent fluidity and storage stability, which often causes problems in the manufacturing process and the quality of the obtained product.

That is, a concentrated dispersion containing a pigment consisting of fine particles is
They often exhibit high viscosity, making them difficult to handle when stirring, mixing, removing the product from a disperser, or transporting the product, and sometimes thickening significantly during storage, making it difficult to use.
Undesirable phenomena such as flooding, 70-ting, reduction in coating film gloss, and discoloration over time occur.

Non-aqueous printing inks or coatings are pigment dispersions whose dispersion medium is an organic liquid containing a vehicle polymer and other auxiliaries; the rheological properties of these dispersions are essentially It depends on the nature of the pigment, which consists of fine particles.

In other words, in a dispersion system in which the fluidity of the dispersion liquid is extremely poor or the viscosity increases significantly over time, the aggregation of the pigment within the system is significant, and the coloring material in such a system is Not only does it have poor fluidity, but its coloring power during spreading is inferior to colorants that maintain a good dispersion state, and coarse aggregates cause unevenness on the painted surface, causing it to lose its smoothness.
Gloss also tends to decrease significantly, thus impairing the commercial value of the object to be coated.

In the case of dispersions with high pigment concentrations, such as printing inks, if you try to improve the viscosity and fluidity of the dispersion, the gloss of the coating will be lost, and if you try to improve the gloss, the fluidity will decrease. However, it has not been easy to produce coating coloring materials that satisfy both fluidity and gloss, as the properties and storage stability have been impaired.

Various methods have been proposed to prevent agglomeration of pigments in non-aqueous paints or printing inks.

For example, Japanese Patent Publication No. 54-34009, British Patent No. 1,342,746, U.S. Patent No. 3,778,
No. 282, etc., describes a dispersant comprising a polyester containing a terminal redexyl group or a salt thereof obtained by dehydrating a nahydroxycarboxylic acid such as 12-hydroxystearic acid.

In addition, Japanese Patent Application Laid-Open No. 54-37082, British Patent Application Publication No. 2,001,083, and U.S. Patent No. 3.8
Specification No. 82,088, Specification No. 4.224,212, West German Patent Application No. 2,830,860, etc. describe the above terminal carboxyl group-containing d IJ ester and poly(lower alkylene). Dispersants made of amine salts or amides obtained by reacting with imines are described.

Sara K, Japanese Patent Publication No. 57-25251, British Patent No. 1
, 373,660 discloses that after the terminal carboxyl group of the above-mentioned terminal carboxyl group-containing polyester is esterified with a noalkylamino alcohol or amidated by reacting with a (dialkylamino)alkylamine, dimethyl sulfate is added. A dispersant in which the terminal tertiary amine group is a quaternary ammonium group is described.

[Problem to be solved by the invention]

Despite the various attempts described above, it has not yet been possible to obtain a dispersant that has sufficiently satisfactory performance in terms of fluidity and color development of the dispersion at high pigment concentrations.

In addition, dispersants derived from dehydrated polyesters of long-chain aliphatic hydroxycaldic acids, such as 12-hydroxystearic acid, have considerable versatility with a variety of pigments; When the dispersion liquid contained therein is used in, for example, metallic ink or baking paint, there is a problem in that it impairs the adhesion between the coating film and the metal, which limits its use.

The problem to be solved by the present invention is to prevent the agglomeration of pigments in the dispersion when dispersing fine powdery solids, especially organic and inorganic pigments, in organic liquids, especially at high pigment concentrations. It is effective in imparting excellent fluidity and dispersion stability, and when used in thermosetting paints or inks,
An object of the present invention is to provide a dispersant that does not reduce the adhesion between a coating film and a metal, and a dispersion containing the dispersant.

[Means to solve the problem]

In order to solve the above problems, the present invention provides (1) (a) an alkali-soluble styrene-acrylic copolymer containing a carboxyl group, and (bl general formula HO(CH2CH20)nR...(I
) (in the formula, R represents an alkyl group or an alkylphenyl group, and n represents an integer of 2 to 2o), (c) dehydrated at a ratio such that carboxyl groups are in excess of hydroxyl groups. The calgexyl group-containing partially esterified product obtained by the reaction (hereinafter referred to as the partially esterified product of the present invention)
and (2) a dispersant comprising a product obtained by reacting polyethyleneimine.

Furthermore, the present invention provides dispersions of pigments and other finely powdered solids in organic solvents or organic liquids such as binder resin solutions in dispersions such as printing inks, paints, and colored bases thereof. A dispersion liquid containing the above-mentioned dispersant as an agent is provided.

Examples of the carboxyl group-containing alkali-soluble styrene-acrylic copolymer used in the present invention include styrene, α-methylstyrene, β-methylstyrene,
- Methylstyrene, m-methylstyrene, p-methylstyrene, α,β-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, p-ethylstyrene, and acrylic Examples include copolymers obtained by copolymerizing a copolymerizable vinyl heptamer mixture containing an acrylic monomer containing a free carboxylic group such as acid or methacrylic acid in a conventional manner. Number average molecular weight is 2,000 or less and acid value is 150-3
00°, preferably 18° to 25°, are preferred.

As a commercially available carboxyl group-containing alkali-soluble styrene-acrylic copolymer used in the present invention, for example, "Johncr" manufactured by S. C.
yl 67'', ``Johncryl 678 J, ``J
ohncryl 680 J, 1'-Johncryl
682 J, etc. Relatively small molecular weight [
Johncryl 682 J is preferred.

These carboxyl group-containing alkali-soluble styrene-acrylic copolymers are useful as binder components for conventional water-based printing inks or as pigment surface coating materials for the production of easily dispersible pigments in aqueous vehicle systems. , U.S. Pat. No. 4,036,652 and U.S. Pat. No. 4,166,811. However, a product obtained by reacting a partially esterified product obtained by reacting these carboxyl group-containing alkali-soluble styrene-acrylic copolymers with a compound represented by general formula (I) and polyethyleneimine is The new finding that it is useful as a pigment dispersant in an organic solvent system was provided for the first time by the present inventors and was previously unknown.

Examples of the compound represented by the general formula (I) used in the present invention include polyoxyethylene lauryl ether, polyoxyethylene tetradecanyl ether, polyoxyethylene hexadecanyl ether, and polyoxyethylene octadecanyl ether. polyoxyethylene dodecenyl ether, polyoxyethylene dodecenyl ether, polyoxyethylene hexadecenyl ether, polyoxyethylene octadecenyl ether, polyoxyethylene hexyl phenyl ether, polyoxyethylene nonylphenyl ether, etc. can be mentioned.

As a commercial product of the compound represented by the general formula (I) used in the present invention, "Emulgun" manufactured by Kao Corporation is suitable.

The dehydration esterification reaction between the carboxyl group-containing alkali-soluble styrene-acrylic copolymer and the compound represented by the general formula (I) is carried out using a known acid catalyst, e.g. Valic acid, p-)
preferably in the presence of an inert gas such as nitrogen, such as luenesulfonic acid, tetra-n-butyl titanate, tetraisopropyl titanate, or methanesulfonic acid as described in Australian Patent No. 493,015. is passed through the reaction system, or the dehydration and esterification reaction is carried out in the presence of an aromatic hydrocarbon that forms an azeotrope with water, e.g., t is toluene or xylene, and the produced water is removed from the reaction system. Preference is given to azeotropic removal. The degree of progress of esterification due to the dehydration reaction can be determined by measuring the amount of distilled water and the acid value of the reactant.

The partially esterified product of the present invention preferably has an acid value in the range of 20 to 120, particularly preferably in the range of 50 to 90.

The polyethyleneimine used in the present invention preferably has a molecular weight in the range of 300 to 10,000.

The ratio of the carboxyl group-containing partially esterified product of the present invention and polyethyleneimine used to produce the dispersant of the present invention is preferably in the range of 99:1 to 80:20, and preferably 99:1 to 90. : A range of 10 is particularly preferred. If the proportion of polyethyleneimine used is more than 20% by weight, the hydrophilicity of the resulting dispersant tends to increase, and when the dispersant is blended into a paint, it tends to impair the water resistance of the paint film, which is not preferable.

The reaction product of a partially esterified product and polyethyleneimine is an amine salt at low temperatures, and forms an amide bond when heated and dehydrated. The presence or absence of amide bond formation can be determined, for example, from an infrared absorption spectrum chart.

Organic liquids used in the dispersion of the present invention include aromatic hydrocarbons such as toluene, petroleum hydrocarbons such as mineral spirit and mineral turpentine; Halogenated hydrocarbons such as benzene; linear or cyclic ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; esters such as ethyl acetate, butyl acetate, amyl acetate, selonlupe acetate; isopropyl alcohol, isobutyl Examples include alcohols such as alcohol and n-butyl alcohol, but of course mixed solvents of two or more of these may also be used, and known alkyd resins,
Epoxy ester resin, epoxy resin, melamine resin,
It may be a mixed system with acrylic resin, polyamide resin, polyurethane resin, polyester resin, salt vinyl acetate resin, phenol resin, nitrocellulose resin, etc.

The powdery solids dispersed in organic liquids by the dispersant of the present invention are usually fine solids with a particle size of 20 microns or less, such as titanium dioxide, red and yellow iron oxides, barium sulfate, hydroxide, etc. Aluminum, calcium carbonate, Merck, clay, silica, magnetic iron oxide, lead chromate,
Various inorganic pigments including colorants, fillers, conductive materials, magnetic materials, etc., such as zinc chromate, strontium chromate, carbon plano cumium aluminum, brass, iron, etc.;
Examples include organic pigments such as azo pigments, lakes, toners, phthalocyanine pigments, isoindolinone pigments, quinacridone pigments, indanthrene pigments, dioxazine pigments, but especially titanium dioxide, red and yellow iron oxides, chromium sulfate, etc. , inorganic pigments and lakes such as calcium carbonate,
The effect is remarkable in toner.

The relative proportion of the dispersant of the present invention in the dispersion liquid is preferably in the range of 0.1 to 100% by weight, particularly preferably in the range of 0.1 to 10% by weight, based on the weight of the material to be dispersed. In addition, the content of the fine powder to be dispersed in the dispersion liquid is 5 to 80% by weight.
The range is preferably from 10 to 70% by weight, particularly preferably from 10 to 70% by weight.

Non-aqueous paints, printing inks, and colored bases thereof produced using the dispersant of the present invention as a pigment dispersant exhibit excellent fluidity and dispersion stability. Or useful in preparing pigment dispersions for printing inks.

The pigment dispersion mentioned here refers to a system consisting of a pigment, an organic liquid, and a dispersant, and it can be easily prepared into a printing ink or coating material by blending it with a desired vehicle depending on the purpose of use. The number of mill bases can be greatly reduced compared to the conventional method, and inventory costs and storage space can be greatly reduced.

Furthermore, as an advantage in application, it can maintain excellent fluidity even at much higher pigment concentrations than ordinary mill bases, so it can be milled in a short time, reducing the amount of labor, electricity, and consumables required for milling. storage, as it can reduce costs;
It is possible to reduce transportation costs and prevent a decrease in yield due to wear resistance loss.

Furthermore, to name a field of application of the dispersant of the present invention, by processing a wet cake of an inorganic pigment such as precipitated calcium carbonate with a high surface polarity in a slurry state, the flushing time for oil-based phenol can be greatly shortened. It is also useful as a flushing aid because it can easily produce a lithographic ink with good dispersibility.

The advantages and characteristics of the dispersant of the present invention in use are (a) reduction in pigment dispersion time and reduction in the number of ink or paint mill bases, and (b) improvement in the state of pigment dispersion in the finished ink or paint. flocculation by stabilization of
Examples include prevention of flooding and floating, improvement of leveling, and (c) shortening of syneresis time in the pigment flushing process.

[Examples] The present invention will be explained in more detail with reference to Examples below, but of course the gist and scope of the present invention are not limited by these Examples.

In addition, parts in the examples mean parts by weight.

Example 1 (Preparation of dispersant) "Johncryl 682j (S, C, John
Low molecular weight alkali-soluble styrene-acrylic comonomer manufactured by Son; Mn = 980, MW = 1620, acid value 235m9KOH//9, softening point 110°C, glass transition point 50°G) 238. El, [Emuldan 105J (polyoxyethylene lauryl ether manufactured by Kao Corporation; H
LB=9.7) 181.0g, octatitanic acid n-
Butyl 0.29, xylene 72.5g in nitrogen stream 1
The mixture was heated under reflux at 70 to 174°C for 8 hours, and 9.09% water was collected in a Dean-Stark lamp and separated.

The reaction mixture was cooled to 70°C and 365.5y of xylene,
Add 21.69 of "Epomin 5P-006J (polyethyleneimine manufactured by Nippon Shokubai Chemical Co., Ltd.; Pilgrimage = 600),
The mixture was heated under reflux at 136-138°C for 1 hour, and 1.89% of water was collected and separated in a Dean-Stark trap.

The reaction product was cooled to room temperature to form a light yellowish brown transparent viscous dispersant 863. :l' was obtained. The nonvolatile content of this dispersant is 4
9%, acid value 38.6, amine value 25.0, viscosity T-U by donor method, and color number 8.

Example 2 (Preparation of dispersion liquid) “Fast Gunpuru NKJ (manufactured by Inu Nippon Ink Chemical Co., Ltd.) Pigment Blue 15-4
) 37.5 parts, 1.9 parts of the dispersant obtained in Example 1, 6.3 parts of "Sue!-Beccamin L-105J (melamine resin manufactured by Dainippon Ink and Chemicals Co., Ltd.)," Tsurpez 15
0” (Esso Oil Co., Ltd., alkylbenzene-based 1 agent) 54
．． Add 200 parts of diameter 3 dragon steel balls to the 3 parts mixture and apply 2 parts with Red Devil Paint Conditioner.
The mixture was shaken for a period of time to peptize and disperse the mixture to obtain a dispersion.

When the viscosity of the obtained dispersion was measured using a B-type viscometer, the viscosity at 60 rotations at 25°C was 600 ep.
◎ The dispersion showed good fluidity and was suitable for mills and mills for PCM coating materials.
It is suitable for producing a base, and no precipitation of the pigment or thickening of the dispersion was observed even after one week of standing.

Example 3 (Preparation of dispersion liquid) "Fast Gun Super Magenta R" (C,1, Pigment Viol manufactured by Dainippon Ink and Chemicals Co., Ltd.)
et 19), 1.2 parts of the dispersant obtained in Example 1, 4 parts of "Super Beckamine L-105", and 70.8 parts of "Tsurupez 150J", 200 parts of steel balls with a diameter of 31 m were added, and red・Devilsha H-'!'17
The mixture was shaken for 2 hours using a water conditioner to deflocculate and disperse the mixture to obtain a dispersion.

The viscosity of the obtained dispersion was measured in the same manner as in Example 2, and was found to be 700 cps.

The dispersion exhibits good fluidity and can be used in mills and mills for PCM coating materials.
It is suitable for producing a base, and no precipitation of the pigment or thickening of the dispersion was observed even after one week of standing.

Comparative Example 1 In Example 3, an attempt was made to manufacture a dispersion liquid using the system obtained in Example 1 without using the dispersant, but the composition was non-flowing, and it was difficult to manufacture a mill base for PCM coating materials. It was inappropriate for

Example 4 (Preparation of dispersion liquid) 70.6 parts of red iron oxide 140MJ (Red pigment from Bayer AG, West Germany), 0.7 parts of the dispersant obtained in Example 1, [Super Beckamine L-105J 11.8 parts] A mixture of 16.9 parts of Tsurupetz 150J and 200 parts of a diameter 3 dragon ceramic was shaken for 2 hours using Red Devil's 4 India conditioner to deflocculate and disperse, to obtain a dispersion.

The viscosity of the obtained dispersion was measured in the same manner as in Example 2, and was found to be 1,300 cps.

The dispersion exhibits good fluidity and can be used in mills and mills for PCM coating materials.
It was suitable for base production and had excellent storage stability.

Comparative Example 2 In Example 4, an attempt was made to manufacture a dispersion liquid using the system obtained in Example 1 without using the dispersant, but one composition was non-flowing, and it was difficult to manufacture a mill base for PCM coating materials. was inappropriate.

Example 5 (1! I Preparation of Materials M) From 80% of ``Dianal 5650J'' (acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.) and 20% of ``Super Beckamine'' (melamine resin manufactured by Dainippon Ink and Chemicals Co., Ltd.) 60 parts of film-forming resin consisting of
0.3 part of the dispersant obtained in Example 1 was added to a mixture of 40 parts of -3J (rutile type titanium white manufactured by BTP) and mixed uniformly to obtain a white enamel paint.

This white enamel paint was applied to a galvanized iron plate using an A40 bar coater and baked at 200'C for 90 seconds to form a paint film.

[Base grain peeling test]

Cut 1) M on this paint film with a safety razor blade, vertically and horizontally.
100 base stitches were created by inserting each piece at 11n intervals, and after applying Chiban Co., Ltd.'s Cellophane Adhesive Tea f) to the "cellotape" on that part, when the "cellotape" was peeled off, it peeled off from the base. There was no basis for it.

Comparative Example 3 In Example 5, instead of the dispersant obtained in Example 1, K
Solus 9-z 13240J (Dispersant from Real Chemical Industries Ltd., UK, 40% hydroxystearic acid copolymer-terminated polyethyleneimine adduct)
A white enamel paint was obtained in the same manner except that a toluene solution (containing toluene solution) was used.

Using this white enamel paint, in the same manner as in Example 5,
A coating film was formed on a galvanized iron plate.

[Base grain peeling test]

When this coating film was subjected to a base grain peeling test in the same manner as in Example 5, no base grains remained on the base.

From the results of the base grain peeling tests conducted in Example 5 and Comparative Example 3, it was found that the dispersant of the present invention has a conventional terminal cal? It will be understood that the coating film formed by the surface coating material obtained by blending the dispersant with the xyl group-containing polyester dispersant has excellent adhesion to metals.

〔Effect of the invention〕

Claims (1)

[Scope of Claims] 1. (1) (a) an alkali-soluble styrene-acrylic copolymer containing a carboxyl group, and (b) a compound having the general formula HO (C
H_2CH_2O)_nR (in the formula, R represents an alkyl group or an alkylphenyl group, and n represents an integer of 2 to 20), and (c) a ratio in which carboxyl groups are in excess of hydroxyl groups. A dispersing agent characterized by comprising a carboxyl group-containing partial esterified product obtained by dehydration reaction with (2) a product obtained by reacting with polyethyleneimine. 2. A dispersion containing a finely powdered solid, an organic liquid as a dispersion medium, and a dispersant, in which the dispersant according to claim 1 is used as the dispersant. 3. The dispersant according to claim 1 or claim 2, wherein the carboxyl group-containing alkali-soluble styrene-acrylic copolymer (1)-(a) has an acid value of 150 to 300. The dispersion described in . 4. Carboxyl group-containing alkali-soluble styrene-acrylic copolymer (1)-(a) has a number average molecular weight of 2.0
00 or less, the dispersant according to claim 1 or the dispersion according to claim 2. 5. Carboxyl group-containing partially esterified product (1)-(c
2. The dispersant according to claim 1 or the dispersion according to claim 2, wherein the carboxyl group content of the dispersant according to claim 1 or 2 has an acid value of 20 to 120. 6. The number average molecular weight of polyethyleneimine (2) is 300
10,000 or the dispersion according to claim 2. 7. The dispersant according to claim 1 or the dispersion according to claim 2, wherein the reaction ratio of the carboxyl group-containing partially esterified product and polyethyleneimine is in the range of 99:1 to 80:20 by weight. . 8. The ratio of dispersant used is 0.1 to the fine powder solid.
A dispersion according to claim 2 in the range from 100% by weight. 9. A paint comprising the dispersion according to claim 2. 10. A printing ink comprising the dispersion according to claim 2. 11. A colored base for paints having a high pigment concentration and comprising the dispersion according to claim 2. 12. A colored base for printing ink having a high pigment concentration and comprising the dispersion according to claim 2.