JP2507810B2 - Pigment dispersant, pigment composition, paint and printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention provides a pigment dispersant that provides pigment dispersion resistance excellent in usability, particularly non-aggregation, non-crystallinity, and fluidity, and The present invention relates to a pigment composition composed of a pigment and a pigment dispersant, and a paint or printing ink.

(Prior Art) In general, practically useful pigments that exhibit a vivid color tone and high coloring power in various coating or ink compositions consist of fine particles. However, it is difficult to obtain a stable dispersion of fine pigment particles when dispersed in non-aqueous vehicles such as offset inks, gravure inks and paints, which has a significant impact on the manufacturing process and the value of the resulting product. It is known to cause various problems.

For example, dispersions containing pigments consisting of fine particles often have high viscosities, which not only makes it difficult to remove and transport the product from the disperser, but in the worse case, it causes gelation during storage and is used. It can be difficult. Further, when different kinds of pigments are mixed and used, color separation due to agglomeration and a decrease in sedimentation may cause color unevenness and a marked decrease in coloring power in the developed product. Furthermore, the coating surface of the color-developed product may have poor gloss, poor leveling, and other defective states.

Although not directly related to the pigment dispersion, some organic pigments have a decrease accompanied by a change in the crystal state of the pigment.

That is, in non-aqueous vehicles such as offset inks, gravure inks, and paints, the crystal particles of energetically unstable pigments change their size and form and shift to a stable state. The commercial value may be impaired due to a decrease in coloring power, generation of coarse particles, and the like.

In order to solve the above-mentioned various problems, many proposals have been made so far centering on copper phthalocyanine pigments and quinacridone pigments.

The contents can be roughly classified into the following two when classified according to the technical method.

The first method involves coating the surface of pigment particles with a colorless compound such as silicon oxide, aluminum oxide and tertiary butyl benzoic acid as disclosed in US Pat.

The second method is to introduce a substituent such as a sulfone group, a sulfonamide group, an aminomethyl group or a phthalimidomethyl group into the side chain with an organic pigment as a base skeleton as represented by JP-B-41-2466 and USP2855403. This is a method of mixing the compounds obtained by.

The second method has a remarkably large effect on the non-aggregation property and crystal stability of the pigment in the non-aqueous vehicle as compared with the first method, and is extremely advantageous even when judged from the ease of producing the pigment composition. Is the way.

(Problems to be Solved by the Invention) The present invention provides a pigment dispersion for obtaining a stable dispersion excellent in non-aggregation, non-crystallinity, and fluidity when manufacturing offset inks, gravure inks, paints, and the like. An agent and a pigment composition are provided.

(Means for Solving the Problem) The pigment dispersant of the present invention comprises a diketopyrrolopyrrole compound, an amino-formaldehyde condensate or an alkoxymethylated product thereof, and optionally substituted phthalimide or N-oxymethylphthalimide. And a compound having a carboxyl group formed by hydrolyzing the compound, or a compound having the carboxyl group forming a salt with a metal ion or an organic amine.

The diketopyrrolopyrrole compound is a compound represented by the formula (I), and these are US Pat. No. 4,415,685, European Patent Application Publication No. 133,156 or Japanese Patent Publication (A) 57-172937, 60- 35056, 61-12086, 6
It is known from 1-183363, 62-149759 and the like.

Formula (I) (The symbols in the formulas are the same as above.) The pigment dispersant of the present invention is, for example, one of the formulas (II) and (III)
The structure is as shown in.

Formula (II) Formula (III) (In the formula, Q represents a diketopyrrolopyrrole compound residue, R ₃ and R ₄ are each independently a hydrogen atom, a halogen atom,
Represents an alkyl group, an alkoxy group, a nitro group, a sulfone group or a carboxyl group. m and n are 0 independently
Represents the number 4. The amino-formaldehyde condensate having a methylol group or an alkoxymethylated product thereof used in the present invention may be a di-substituted compound or a hexa-substituted compound. When melamine is selected as the raw material of the amino-formaldehyde condensate, it is industrially preferable to use a raw material containing a mono-substituted product to a hexa-substituted product and a polymer thereof. Similarly, in the case of a methylol compound of benzoguanamine or urea or an alkoxymethyl compound thereof, an excellent pigment dispersing effect can be obtained regardless of the number of substituents.

The pigment dispersant obtained in the present invention has a methylol group or an alkoxymethyl group which is not necessarily phthalimide or N.
-It is not necessary to completely react with oxymethylphthalimide, and some methylol groups or alkoxymethyl groups may remain unreacted.

The pigment dispersant of the present invention uses an amino-formaldehyde condensate such as a methylol compound such as melamine, benzoguanamine or urea, or an alkoxymethylated product thereof as a starting material, and also uses melamine, benzoguanamine or urea and the like and paraformaldehyde and It is also possible to use alcohol as a starting material.

In addition, the pigment dispersant obtained in the present invention is obtained by a crosslinking reaction of a diketopyrrolopyrrole compound as a raw material with an amino-formaldehyde condensate or an alkoxymethylated compound. Contains. Even in this case, a very excellent dispersion effect is exhibited.

Formula (IV) (In the formula, Q, R ₃ , and n are the same as those shown in the formulas (II) and (III).) When N-methylolphthalimide is used as a raw material, it is possible to obtain a diketopyrrolopyrrole-based compound skeleton. A compound such as the formula (V) in which a phthalimide group is directly introduced is produced, but even in this case, an extremely excellent dispersion effect is exhibited.

Equation (V) (In the formula, Q, R ₃ , R ₄ , n, and m are the same as those shown in formulas (II) and (III).) Further, for example, the phthalimido group represented by formula (VI) was hydrolyzed. The compound and its metal salt or organic amine salt also show an extremely excellent dispersing effect.

The metal forming the metal salt or the organic amine salt and the organic amine are not particularly limited.
The metal may be sodium, calcium, barium, aluminum, strontium, zinc, manganese, etc., and the organic amine has 8 to 24 carbon atoms such as caprylamine, octylamine, laurylamine, stearylamine. The case where it is an aliphatic primary amine is mentioned.

Formula (VI) (In the formula, Q, R ₃ , R ₄ , n, and m are the same as those shown in the formulas (II) and (III).) As a reaction solvent for producing the pigment dispersant of the present invention, sulfuric acid, polyphosphoric acid, or the like is used. Acids can be used. When the pigment dispersant of the present invention is produced, the amino-formaldehyde condensate or its alkoxymethylated product is contained in an amount of 0.2 to 6 mol per 1 mol of the diketopyrrolopyrrole compound, optionally substituted phthalimide and N-oxymethyl. When phthalimide is used as a raw material in an amount of 0.2 to 10 mol, the compound with the best dispersion performance can be obtained. Even if the phthalimide is produced at a charged molar ratio outside this range, the amount of impurities will increase, but the amount added will increase practically. By doing so, a sufficient dispersion effect can be obtained.

The pigment dispersant obtained in the present invention exhibits an excellent dispersing effect on almost all pigments that are generally commercially available. For example, azo pigments such as diketopyrrolopyrrole pigments, soluble and insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, perylene / perinone pigments, dioxazine pigments,
Organics such as anthraquinone pigment, dianthraquinonyl pigment, anthrapyrimidine pigment, anthanthrone pigment, indanthrone pigment, flavanthrone pigment, pyranthrone pigment, vat dye pigment, basic dye pigment It can be used for pigments and inorganic pigments such as carbon black, titanium oxide, yellow lead, cadmium yellow, cadmium red, rouge, iron black, zinc white, navy blue, ultramarine.

The blending of the pigment dispersant obtained in the present invention with the pigment is as follows:
0.1 to 30 parts by weight is preferable for 100 parts by weight of the pigment. If the amount is less than 0.1 part by weight, the effect of the pigment dispersant obtained in the present invention cannot be obtained, and if the amount is more than 30 parts by weight, the effect of the amount used cannot be obtained.

The method of using the pigment dispersant according to the present invention includes, for example, the following method.

1. A pigment composition obtained by previously mixing a pigment and a pigment dispersant is added to a non-aqueous vehicle or the like and dispersed.

2. The pigment and the pigment dispersant are separately added and dispersed in a non-aqueous vehicle or the like.

3. Separately disperse the pigment and pigment dispersant in a non-aqueous vehicle or the like in advance and mix the resulting dispersion.

 In this case, the pigment dispersant may be dispersed only with the solvent.

4. After dispersing the pigment in a non-aqueous vehicle or the like, a pigment dispersant is added to the resulting dispersion.

The desired effects can be obtained by any of these methods.

As a method for preparing the pigment composition shown in the above 1, even if the pigment powder and the powder of the pigment dispersant according to the present invention are simply mixed, the desired effects can be sufficiently obtained, but kneader, roll mill, attritor, supermarket Mechanically mixing with a mill or various crushers, or adding a solution containing the pigment dispersant according to the present invention to a suspension system of pigment or water or an organic solvent to deposit the pigment dispersant on the pigment surface, or sulfuric acid. Even better results can be obtained by performing a close mixing method such as co-dissolving an organic pigment having a strong dissolving power such as, for example, and a pigment dispersant and coprecipitating with a poor solvent such as water.

In the use of a pigment and a pigment dispersant as described in 2 to 4 above, dispersers and high-speed mixers are used as dispersing machines for dispersing a pigment or a pigment dispersant in a non-aqueous vehicle or a solvent, mixing these, and the like. By using a homomixer, a kneader, a roll mill, a sand mill, an attritor, etc., the pigment can be dispersed well.

In the present invention, the pigment dispersion is applied to include paints and printing inks.

In paints, the pigment composition of the present invention is 0.1 to 15% by weight, the vehicle for paint is 99.9 to 55% by weight, other auxiliary agents and extender pigments are 0%.
-30% by weight, the vehicle for paint is acrylic resin,
Alkyd resin, epoxy resin, chlorinated rubber, vinyl chloride,
Synthetic resin emulsion, silicone resin, water-soluble resin,
It comprises 80 to 20% by weight of polyurethane, polyester, melamine resin, urea resin or a mixture thereof and 60 to 10% by weight of solvent such as hydrocarbon, alcohol, ketone, ether alcohol, ether, ester and water.

The gravure ink comprises 3 to 20% by weight of the pigment composition of the present invention, 97 to 60% by weight of a vehicle for gravure ink, and 0 to 20% by weight of other auxiliary agents and extender pigments. The vehicle for gravure ink includes gum rosin, wood rosin, Tall oil rosin, lime rosin, rosin ester, maleic acid resin, polyamide resin, vinyl resin, nitrocellulose,
Resin mixture such as cellulose acetate, ethyl cellulose, ethylene-vinyl acetate copolymer resin, urethane resin, polyester resin, alkyd resin, gilsonite, dammar, shellac 10 to 50% by weight, hydrocarbon, alcohol, ketone, ether alcohol, ether, ester , 30 to 80% by weight of a solvent such as water.

The offset ink comprises 3 to 35% by weight of the pigment composition of the present invention, 97 to 45% by weight of the vehicle for offset ink, and 0 to 20% by weight of other auxiliary agents and extender pigments. The vehicle for offset ink is a rosin-modified phenol resin, 20 to 50% by weight of resin such as petroleum resin, alkyd resin or dry oil-modified resin, 0 to 30% by weight of vegetable oil such as linseed oil, tung oil, soybean oil, n-paraffin, isoparaffin,
Aromatech, naphthene, solvent such as α-olefin 10
-60% by weight.

〔The invention's effect〕

According to the present invention, compared with the case where the pigment is used alone, it exhibits good fluidity such as a decrease in viscosity of the dispersion and a decrease in structural viscosity, and at the same time, there is no problem such as color separation, change of crystals, etc. Has a good gloss, and thus a beautiful product can be obtained.

In particular, the pigment dispersant according to the present invention has an extremely excellent dispersing effect not only in oil-modified amino alkyd resin coatings but also in oil-free alkyd resin coatings.

Further, the use of the pigment dispersant according to the present invention is not limited to the non-aqueous vehicle, and other printing inks, paints,
Furthermore, even in the coloring of plastics, it is possible to obtain a colored product having an excellent dispersing effect and a strong coloring power.

Hereinafter, production examples of the pigment dispersant according to the present invention will be described. In addition, the following "parts" represent "parts by weight", and the numbers of the pigment dispersants in the production examples correspond to the abbreviations of the pigment dispersants shown in Table 1.

[Production Example 1] 6 parts of the diketopyrrolopyrrole compound represented by the formula (VII) was dissolved in 400 parts of 98% sulfuric acid, 20 parts of dimethylolbenzoguanamine was added at 10 to 20 ° C, and the mixture was stirred at the same temperature for 2 hours. Then, 50 parts of tetrachlorophthalimide was added, and the mixture was stirred at 80 to 90 ° C for 4 hours.

The reaction solution was poured into 5000 parts of ice water, filtered, washed with water and dried to obtain 41 parts of Pigment Dispersant (1).

Formula (VII) [Production Example 2] 40 parts of a pigment dispersant (2) was obtained in the same manner as described above, except that 6 parts of the compound represented by the formula (VIII) was used in place of the compound represented by the formula (VII). .

Formula (VIII) [Preparation Example 3] 44 parts of a pigment dispersant (3) was obtained by the same method, using 6 parts of the compound represented by the formula (IX) in place of the compound represented by the formula (VII) in Preparation Example 1. .

Expression (IX) Production Example 4 16 parts of the diketopyrrolopyrrole compound represented by the formula (X) was dissolved in 300 parts of 98% sulfuric acid at 10 to 20 ° C, and 40 parts of trimethylolmelamine was added at 10 to 20 ° C. 20-30 ° C after addition
The mixture was stirred for 2 hours, 90 parts of N-oxymethylphthalimide was added, the temperature was raised at 20 to 30 ° C for 1 hour, and the mixture was stirred at 50 ° C for 6 hours. The reaction solution was poured into 4000 parts of ice water, filtered, washed with water, and dried to obtain 98 parts of a pigment dispersant (4).

Formula (X) Production Example 5 Pigment Dispersant (5) 95 parts was obtained in the same manner by using 14 parts of the compound represented by the formula (VII) instead of the compound represented by the formula (X) in Production Example 4. .

[Production Example 6] Pigment dispersant (6) (103 parts) was obtained by the same method, using 95 parts of 4-nitro-N-oxymethylphthalimide instead of N-oxymethylphthalimide of Preparation example 4.

[Production Example 7] 15 parts of phthalimide was dissolved in 300 parts of 98% sulfuric acid to prepare methylol urea (80% dimethylol urea, monomethylol urea).
20%) was added at 20 to 30 ° C, and the mixture was stirred at the same temperature for 1 hour, then heated and stirred at 50 to 60 ° C for 4 hours. Cool down 20
To 30 and 7 parts of the diketopyropyrrole compound represented by the formula (VII) was added, and the mixture was stirred at the same temperature for 1 hour and then heated to 70 ° C. for 2 hours. The reaction solution was poured into 1000 parts of ice water, filtered, washed with water and dried to obtain a pigment dispersant (7).

[Production Example 8] A similar method using 20 parts of 4-nitrophthalimide in place of the phthalimide of Production Example 7 and the compound 7 of the formula (VIII) in place of the compound of the formula (VII) This gave 30 parts of Pigment Dispersant (8).

[Production Example 9] 24 parts of the pigment dispersant (5) obtained in Production Example 5 was placed in 400 parts of a 1% aqueous sodium hydroxide solution, and stirred at 90 to 100 ° C for 2 hours for hydrolysis. Then add hydrochloric acid to adjust the pH to 3
The purified product dissolved as a sodium salt was precipitated, filtered, washed with water and dried to obtain 22 parts of a pigment dispersant (9).

[Production Example 10] 12 parts of the pigment dispersant (9) obtained in Production Example 9 was put in 300 parts of water, adjusted to pH 9 with sodium hydroxide, 10 parts of aluminum sulfate was added, and the mixture was stirred at 50-60 ° C for 1 hour. , Filtration,
It was washed with water and dried to obtain Pigment Dispersant (10) 13.

[Production Example 11] 17 parts of a pigment dispersant (11) was obtained in the same manner by using 12 parts of laurylamine acetate instead of the aluminum sulfate of Production Example 10.

[Production Example 12] 13 parts of melamine were dissolved in 300 parts of 98% sulfuric acid at 10 to 20 ° C,
Then add 18 parts of paraformaldehyde below 20 ℃,
Heat and stir at 70-80 ° C. for 4 hours. Then cool down 20 ~
The temperature was adjusted to 30 ° C., 15 parts of the diketopyrrolopyrrole compound represented by the formula (IX) was added, and the mixture was stirred at the same temperature for 2 hours. Then 4
-65 parts of nitrophthalimide was added, and the mixture was stirred at 50-60 ° C for 3 hours. The reaction solution was poured into 5000 parts of ice water, filtered, washed with water and dried to obtain 55 parts of a pigment dispersant (12).

In order to evaluate the effect of the pigment dispersant according to the present invention, a paint having the following composition was prepared.

Formulation (1) Pigment 9.5 parts Pigment dispersant 0.5 part Alkyd resin-based varnish (non-volatile content 60%) 26.4 parts Melamine resin-based varnish (non-volatile content 50%) 13.6 parts Thinner 20 parts (xylene / n-butanol = 8/2) 48.3 parts of mixed varnish added after dispersion (alkyd / melamine = 7/3 (solid content)) Formulation (2) Pigment 9.5 parts Pigment dispersant 0.5 part Oil-free polyester resin varnish 26.4 parts (nonvolatile content 60%) Melamine resin Varnish (non-volatile content 50%) 13.6 parts Swazole 20 parts Mixed varnish added after dispersion 48.3 parts (alkyd / melamine = 7/3 (solid content)) Put the above mixture in a container, add steel ball and paint Dispersed with a shaker to make paint. These paints were compared with a paint to which a pigment dispersant was not added (a paint in which the pigment dispersant was not added in the above formulation and the amount of the pigment was 10 parts) according to the following evaluation method. Table 1 shows an example of the results.

Evaluation method (1) The viscosity of the obtained coating material was measured by a B type viscosity system and judged (measurement temperature 25 ° C.). The evaluation was made by a relative comparison with the paint without the pigment dispersant added, and the one having a low viscosity was regarded as good.

◯: Good Δ: Fairly good ×: Poor Evaluation method (2) The obtained paint had a final paint viscosity of 23 for Ford cup 4.
It was adjusted with a thinner so that it would be in seconds, sprayed on a tin plate with an air spray gun, then baked, and visually evaluated the 20 ° gloss with a gloss meter for a comprehensive evaluation of the sharpness of the coated surface.

○: Excellent △: Good ×: Poor These paints showed almost no increase in viscosity even when measured for viscosity with the same viscometer after being left for 1 week. In addition, a 1 / 10-cut light-colored paint was prepared using a white paint adjusted with titanium white, the viscosity was adjusted to 23 seconds with a Ford cup 4, and placed in a test tube to observe the aggregation state. No separation or sedimentation was observed.

Furthermore, the pigment to which the pigment dispersant according to the present invention was added showed good dispersibility even in nitrocellulose lacquer, access resin paint and gravy ink without causing aggregation.

Claims (7)

(57) [Claims] 1. A pigment dispersant obtained by reacting a diketopyrrolopyrrole compound, an amino-formaldehyde condensate or an alkoxymethylated product thereof, and optionally substituted phthalimide or N-oxymethylphthalimide. 2. A pigment dispersant having a carboxyl group obtained by hydrolyzing the pigment dispersant according to claim 1. 3. A pigment dispersant comprising a salt of the pigment dispersant according to claim 2 and a metal ion or an organic amine. 4. A diketopyrrolopyrrole compound is represented by the formula (I)
The pigment dispersant according to any one of claims 1 to 3, which is a compound represented by: Formula (I) (Wherein X represents an oxygen or sulfur atom, A and B may be the same or different from each other, alkyl, aralkyl, cycloalkyl, aryl or carbocyclic or heterocyclic aromatic R ₁ and R ₂ represent a hydrogen atom, an unsubstituted or substituted alkyl residue, alkenyl, alkynyl, aralkyl, cycloalkyl, carbamoyl, alkylcarbamoyl, arylcarbamoyl, alkoxycarbonyl, aryl,
Represents an alkanoyl or aroyl group. ) 5. A pigment composition comprising a pigment and the pigment dispersant according to any one of claims 1 to 3. 6. The method according to any one of claims 1 to 3 with respect to 100 parts by weight of the pigment.
A coating material comprising 0.1 to 30 parts by weight of the pigment dispersant according to any one of claims 1 to 4 and a vehicle for coating material. 7. The method according to any one of claims 1 to 3 with respect to 100 parts by weight of the pigment.
A printing ink comprising 0.1 to 30 parts by weight of the pigment dispersant according to any one of claims 1 to 4 and a vehicle for printing ink.