JPS60137924A - Resin for dispersing pigment - Google Patents

Abstract

PURPOSE:The titled resin, obtained by condensing a polymer of star-shaped structure consisting of a polycarboxylic acid and epsilon-caprolactone with a polyol compound, and having improved compatibility with vehicles for coating materials, e.g. alkyd resin, and a low viscosity. CONSTITUTION:A resin for dispersing pigments, obtained by condensing (A) a polymer of star-shaped structure prepared by reacting (i) a polycarboxylic acid having 3 or more carboxyl groups, e.g. pyromellitic acid, with (ii) epsilon-caprolactone with (B) a polyol compound having plural hydroxyl groups, e.g. ethylene glycol, to satisfy the ratio between the number of moles of carboxyl groups [COOH] in the component (A) and the number of moles of hydroxyl groups [OH] in the component (B) in the formula [f is the number of hydroxyl functional groups in the component (B)], and introducing basic groups if necessary thereinto with a usual basic group introducing reagent. EFFECT:A coating material composition containing a dispersed pigment with a high solid content is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides pigment dispersion resins that exhibit good compatibility with paint vehicle resins such as polyester and norkyd resins, and pigment dispersion pastes containing the resins. The present invention also relates to a pigment-dispersed coating composition containing the pigment-dispersed paste.

Conventionally, in order to prepare a pigment-dispersed coating composition, it is common to uniformly mix a pigment with a pigment-dispersing resin to form a pigment-dispersed paste, and then uniformly mix this into a coating vehicle. As the above pigment dispersing resin, a part of the paint vehicle itself or a resin different from the paint vehicle has been used.

However, in the latter case, it must have excellent compatibility with the vehicle resin, and it must also be able to provide good dispersion stability depending on the surface characteristics of the pigment used. In order to improve pigment dispersion stability, it has been proposed and widely put into practice to introduce appropriate acidic and/or basic groups into the resin depending on the surface properties of the pigment (Japanese Patent Application No. 1983).
No. 6-138062).

By the way, polyester paints generally have excellent coating film performance such as weather resistance, chemical resistance, heat resistance, etc.
Although it occupies an important position in the paint field, when considering pigment dispersion resins for such paints, not only the compatibility with the resin vehicle but also the coating film performance of the dispersion resin itself is an issue. It is required to have weather resistance and other properties. Therefore, it is preferable that the resin for pigment dispersion be of the polynisder type as much as possible.

Furthermore, it is desirable for the pigment dispersion system to have as low a viscosity as possible, and therefore it is desirable that the resin for pigment dispersion also have as low a viscosity as possible, but polyester resins conventionally used as paint resins have high viscosity and require a large amount of solvent The present inventors previously found that a polymer with a star structure has a lower viscosity than a linear polymer, and obtained a polyether-type star polymer between polymers. It was very successful. However, although this poly-1-del type resin has low viscosity properties and can be used for pigment dispersion, it is difficult to obtain excellent weather resistance and is not suitable for polynis del-based paints. The present inventors have arrived at the present invention as a result of intensive research to obtain a low-viscosity star-shaped polyester resin useful as a resin for dispersing pigments in paints using polyester resin vehicles such as polyester resins and alkyd resins.

That is, according to the present invention, a star-structured polymer obtained by the reaction of a polycarboxylic acid having at least three carboxyl groups in one molecule and an epsilon-caprolactone, and at least two hydroxyl groups in one molecule. The molar amount of carboxyl groups [C0OH] of the polymer and the molar amount of hydroxyl groups [OH] of the polyol compound are mixed in the following ratio (however, in formula 1, t indicates the number of hydroxyl functional groups of the hydroxyl compound). ) A basic group is introduced, if necessary, into a polymer having a star-shaped structure obtained by a condensation reaction, thereby providing a pigment dispersing resin comprising the resulting modified polymer. The core polycarboxylic acid used as a starting material in the present invention is
Polycarboxylic acids having at least three carboxyl groups in the molecule, specifically, for example, aconitic acid, trimellitic acid, medylcyclohexentricarboxylic acid, pyromellitic acid, methanetetraacetic acid, mellitic acid, etc. Examples include polybasic acids. Epsilon caprolactones represented by the formula (wherein R2 is hydrogen or an alkyl group) are added to the polycarboxylic acid, such as epsilon caprolactone, which has a substitution period ranging from monomethyl, monoedylene, monoisopropyl, etc. to monododecyl. Monoalkyl-epsilon-caprolactone, such as caprolactone, or dialkyl-epsilon-caprolactone, such as in which two alkyl groups are substituted on the same or different carbon atoms, or in which two or three carbon atoms are substituted. Catalysts such as trialkyl-epsilon-caprolactone (
For example, the reaction is usually carried out at 130°C or higher in the presence of a metal chelate such as tin, titanium, zinc, zirconium, beryllium, magnesium, calcium, strontium, barium, manganese, iron, cobalt, nickel, copper, cadmium, lead, or grammarum. This makes it possible to easily produce star-shaped structural polymers.

The polymer chain of this star-shaped structured polymer [in other words, it has a carboxyl group at the end and is a semi-solid to solid product at room temperature, but in the present invention, this terminal carboxyl group is used to A polyol compound having at least two hydroxyl groups is condensed to form a liquid star-shaped polynisdel.

In the present invention, any polyol compound having at least three hydroxyl groups in the molecule can be used, but representative polyol compounds include, for example, ethylene glycol, propylene glycol, 1.3 butylene glycol, and 1,6 hexane dichloromethane. A-ru, diethylene glycol,
Gib II pyrene glycol, neopentyl glycol,
1~lyethylene glycol, hydrogenated bisphenol Δ,
Examples include diols such as bisphenol dihydroxypropyl ether, triols such as glycerin, trimethylolethane, trimethylolpropane, and 1-lishydroxymethylaminomethane, and high molecular weight polyols such as polyethylene glycol and polypropylene glycol. In this case, the carboxyl group mole 1 [C0OH] of the star-shaped polymer and the hydroxyl group mole fl [OH] of the polyol compound should be completely reacted in a ratio of (where f is the number of hydroxyl functional groups of the polyol). is important. That is, depending on the surface properties of the pigments to be used in combination with the resin product, the proportion of the polyol compound is determined so that acidic groups remain in the polymer.

In the reaction between the star-shaped polymer and the polyol compound, the polymer may have a high molecular weight and eventually gel, according to the reaction formula: 2R1-COOH→-HO-R20H-11-→polymer polyol. However, gelation did not occur at all even in the presence of a large amount of solvent, and the results of intermolecular reaction (measured by gel permeation chromatography) of the obtained modified polymer showed that no intermolecular reaction was observed. It has been found that there are few Moreover, the polyol-modified polyester resin thus obtained is semi-solid to liquid (molecules 115
000, it tends to become semi-solid), and when dispersing basic pigments, a stable dispersion with a low viscosity is obtained, which is stable and does not substantially change even after a long period of time. . When an acidic pigment is selected as a pigment, the modified polyester resin is treated with a base by making use of the hydroxyl group at the end of its chain and reacting with an ordinary basic group-introducing reagent under conditions that allow it to react with the hydroxyl group. In this case, a basic group means an electron-donating group, and a nitrogen atom-containing group having a lone pair of electrons is a typical example.

Preferred basic groups include isocyanate compounds, such as monomer compounds such as naphthylene diisocyanate, phenylene diisocyanate, isophorosodiisocyanate, tolyl isocyanate, diphenyl ether diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and diphenylmethane diisocyanate, or their polymers. A compound with reduced toxicity through molecular weighting (hexamethylene diisocyanate-based Duranate EXPD-10)
1″ (Asahi Kasei ■), Death module TPL-2291
” (Sumitomo Bayer■), “°Coronate E H” (Japan Polyurethane■), xylylene diisocyanate-based “
Takenate D12ON” (Takeda Pharmaceutical ■), isoborone diisocyanate-based Padesmodur Z 4370”
(Sumitomo Bay Xl (41!L; Nido), melamine compounds, such as compounds obtained by combining melamine and formaldehyde, or compounds obtained by eliminating the presence of alcohol during this condensation (as methylated melamine, "Synul 303", ``Cineul 300'' (Mitsui Toatsu ■),
Passumimar 40W (Sumitomo Chemical ■), Kneepan 208E-60” (three J1 bundle pressure @
), isobutylated melamine MF-013'' (Nippon Paint etc.), hydroxylamine compounds such as heptanoethanolamine, di]-tanolamine, aminopentanol, aminobenzyl alcohol, 2-dimethylamineethanol, etc., amino acids Compounds such as 3
-dimethylaminobenzoic acid, 2-aminoisobutyric acid, 4-
Examples include polyamide compounds such as amino-n-acetic acid.

Among these, it is particularly desirable to use isocyanate compounds and melamine compounds.

When reacting a star-structured polymer with these basic group-introducing reagents, the number of moles of the latter is usually equal to or less than the number of hydroxyl groups present in the former molecule (preferably the number of moles It may be used in a molar amount corresponding to 0.1 to 50% of

In this way, the pigment dispersing resin according to the present invention can be combined with any pigment, whether it is an acidic pigment or a basic pigment, and whether these pigments are inorganic or organic. I don't mind. Specific examples of inorganic pigments include zinc white,
Titanium oxide, antimony white, iron black, red iron, red lead, cadmium yellow, zinc sulfide, lithopone, barium sulfide,
Examples of organic pigments include lead sulfate, barium carbonate, lead white, and alumina white. Specific examples of organic pigments include azo pigments, polycondensation pigments, metal complex azo pigments, benzimidacylon pigments, and phthalocyanine pigments (blue, green, etc.). )
, dioindigo series, anthraquinone series, flavanthrone series, indanthrene series, anthrapyridine series, bilanthrone series, isoindolinone series, perylene series, perinone series, quinacridone series, and the like. The part where pigment is used is
Usually 10 to 90% based on the total weight of modified polymer and pigment
% (weight preferably 30 to 70% (weight W)). Pigment dispersion paste may be composed only of a modified polymer and a pigment as described above, but it may contain appropriate resins, solvents, modifiers, etc., as long as it does not have an essentially adverse effect on its dispersibility. May be blended.

The resin of the present invention is a polyester-based resin, and when a polyester-based resin such as a polyester resin or an al-4-nide resin is used as a resin vehicle when making a paint, the mutual compatibility of the resins and the coating property are 0, and particularly desirable effects are obtained. If desired, it can be blended with acrylic resin, melamine resin, epoxy resin, polyurethane resin, polyamide resin, urea resin, polyether resin, etc.

There is no particular restriction on the blending ratio of the pigment dispersion paste and the paint vehicle, but it is usually 1:99 to 99:1 (weight ratio). Note that appropriate resins, solvents, modifiers, etc. may be added as necessary.

Specific examples of solvents that can be appropriately blended into the above-described C1 pigment dispersion paste and pigment dispersion coating composition include hydrocarbon solvents (e.g., toluene, xylene, Tsurupez 100, Tsurupez 150), ester solvents. (eg, ethyl acetate, butyl acetate), ketone solvents (eg, methyl ethyl ketone, methyl isobutyl ketone), and the like.

In addition, when preparing the above-mentioned pigment dispersion paste or pigment dispersion coating composition, it is sufficient to employ ordinary dispersion and mixing means, for example, a dispersion machine such as a roll mill, a ball mill, a sand mill, a planetary mixer, a high-speed dispersion, etc. is used. .

The pigment dispersion coating composition thus obtained can maintain a good dispersion state for a long period of time, and its coating film performance is also excellent. What is especially noteworthy is that compared to conventional pigment dispersion compositions, the solid pigment content can be maintained much higher. That is, when performing a painting operation using a pigment-dispersed coating composition, if the viscosity of the composition is too high, the operation becomes difficult. In order to maintain a suitable working viscosity, significant amounts of solvent must be incorporated, resulting in a reduction in solids content. In recent years, spray painting has often been adopted in painting operations due to its efficiency, and this tendency is particularly noticeable when painting industrial or large J or W patterns. Therefore, there has been a strong demand for a pigment-dispersed coating composition that has a high solids content and does not cause any hindrance to the work. The pigment dispersion coating composition according to the present invention meets these demands, and is also great for improving coating efficiency and saving money during solvent use! Uηru b
It is. EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Production Example 1 Production of Dispersing Resin 1 Pyromellitic acid 12.711, epsilon-caprolactone 85.5o and di-n-butyltin oxide 0.17a as a catalyst were mixed in a 500 mff round bottom equipped with a stirring bar, condenser and thermometer. The mixture was placed in a flask and heated at 180°C for about 3 hours. The resulting polymer was a white waxy solid.

Next, 65.5 degrees of this waxy solid, 15.711 degrees of 1.6 hexanediol and 0.0 percent of methanesulfonic acid as a catalyst.
Kijirol 100IIle as oso solvent, approx.
Refluxed at 0°C for 18 hours.

Generated water 2.4. After mQ reflux, the solvent Kyjirol in the reaction product was removed using an evaporator.

The obtained polymer was a light yellow liquid having an acid value of 10°, 8 molecules ffiMn-=2364, and a viscosity of 191 cps (60% Quijirole solution).

Example 1 Production of pigment dispersion paste (1) Dispersion resin i obtained in Production Example 1 i5. og, white pigment CR-95
(Pour 85 g of Ishihara Sangyo (l wood titanium oxide), 7.14+1 isobutanol and 14.28 g of Kijiroru in a 250 mff mayonnaise bottle and disperse with a paint shaker for 20 minutes using Glass Peas 1400 with a diameter of 1 mm as a dispersion medium. Dispersion paste (1) (NV=
82°4%) was obtained. The 20° specular gloss of this paste was 51 and the viscosity was 373 cps.

Production Example 2 Production of Dispersion Resin 2 16.9 g of pyromellitic acid, 183 g of epsilon-caprolactone, and 0.0 g of di-n-butyltin oxide as a catalyst.
2a was heated under the same conditions as in Production Example 1. (The polymer obtained was a white waxy solid C.

Then to this waxy solid 195111.1.6: 1: 27.50 of Sandiol and 0.1 g of methanesulfonic acid as a catalyst and 250 ml (l) of Kijirole as a circulating solvent were added and linolaxed for about 150'Cr'' for 26 hours. (Produced water: 4.2 mff) After reflux, the solvent Kyjirol in the reaction product was removed by an evaporator.The obtained polymer was a pale yellow liquid (oxidized 5.5 molecular weight Mn 3
400. Viscosity 240 cps (60% Kijirol solution)
Met.

Example 2 Production of pigment dispersion paste (2) Dispersion paste (2) (NV=82.4) was prepared in exactly the same manner as in Example 1 except that dispersion resin 2 was used instead of dispersion resin 1.
%) is 40. The 20° specular gloss of the dispersed paste (2) was 51, and the viscosity was 599 cps.

Comparative Example 1 Alkyd resin (Nippon Paint side, molecular weight Mn 28001
Viscosity 5248cps, NV=60%, acid value 5.0>2
5g (solid content 15g), white pigment CR-95 (Ishihara Sangyo ■) 8El, and isobutanol 7.14 as a solvent.
i111 Kijiroru 4.28 () was placed in a mayonnaise bottle with a capacity of 250 mg, and glass beads 14 (M) with a diameter of 1 mm were used as a dispersion medium. When shaken for 20 minutes in a C paint shaker, the beads did not move at all and a good dispersion state was obtained. It was not possible to obtain a dispersed paste.

Comparative Example 2 In Comparative Example 1, oil-free polyester resin (Nippon Paint molecular ff1Mn24) was used instead of alkyd resin.
00, viscosity 980cps, NV=60%, acid value 6.0
Dispersion paste (NV
82.4%). This dispersed paste had a 20' specular gloss of 6 and a viscosity of 1807 cps.

Claims (2)

[Claims] (1) A star-structured polymer obtained by reacting a polycarboxylic acid having at least three carbo-4:sil groups in one molecule with ε-caprolactones has at least two hydroxyl groups in one molecule. The polyol compound is added to the carboxyl group mol I [COO1-
A pigment dispersion made of a modified polyester obtained by conducting a condensation reaction such that the ratio of 11 and Polymer's hydroxyl group mole l [OH] is (where f is the number of hydroxyl functional groups of the polyol compound), and optionally introducing a basic group. Resin for use. (2) A star-structured polymer obtained by the reaction of a polycarboxylic acid having at least three carboxyl groups in one molecule and an ε-cubone lactone has at least two hydroxyl groups in one molecule. The polyol compound is added to the carboxyl group molar m [000
1-1] and the mole of hydro-1-syl groups of the polyol m [0
1-1] (where f is the number of hydroxyl functional groups of the polyol compound) A pigment dispersion consisting of a pigment uniformly dispersed in a modified polyester resin obtained by carrying out a condensation reaction and introducing a basic group if desired. A coating composition comprising a paste and a polynisder resin vehicle.