JPH049192B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an azo pigment dispersant that is suitable for use, particularly excellent in non-aggregation and non-crystallinity. In general, practically useful pigments that exhibit vivid color tones and high tinting power in various coating compositions are composed of fine particles. However, when fine particles of pigments are dispersed in non-aqueous vehicles such as offset inks, gravure inks and paints, it is difficult to obtain stable dispersions, which is important for manufacturing reasons and for the value of the resulting product. This causes various problems that have a negative impact. For example, dispersions containing pigments made of fine particles often have a high viscosity, making it difficult to remove the product from the dispersion machine and transport it, and even worse, gelation occurs during storage, making it difficult to use. It may become. Also, when using a mixture of different pigments,
Phenomena such as color separation due to aggregation or sedimentation may cause color unevenness or a significant decrease in coloring power in the developed product. Furthermore, the surface of the paint film of the developed product may suffer from poor conditions such as reduced gloss and poor leveling. Further, although not directly related to pigment dispersion, some organic pigments experience a phenomenon that involves a change in the crystalline state of the pigment. In other words, in non-aqueous vehicles such as offset inks, gravure inks, and paints, pigment crystal particles, which are energetically unstable, change their size and shape and shift to a stable state, resulting in a noticeable hue in the developed product. Product value may be impaired due to changes in color, decrease in coloring power, generation of coarse particles, etc. As described above, a number of proposals have been made, mainly copper phthalocyanine and quinacridone pigments, for the purpose of improving the non-aggregation properties and crystal stability of pigments. For example, as typified by Japanese Patent Publication No. 41-2466 and USP 2761865, pigments are obtained by using an organic pigment as a base core and introducing substituents such as a sulfon group, sulfonamide group, aminomethyl group, or phthalimidomethyl group into the side chain. This is a method of mixing a dispersant. These methods have a remarkable effect on pigment non-aggregation, crystal stability, etc. in a non-aqueous vehicle, and are very advantageous judging from the ease of manufacturing the pigment composition. . On the other hand, regarding azo pigments and acetoacetanilide yellow pigments, Japanese Patent Publication No. 45-11026,
As represented by Japanese Patent Publication No. 55-49087, a sulfonic acid group,
Although many patent applications have been filed for introducing acidic groups such as carboxyl groups, the introduction of acidic groups into red azo pigments has only been attempted in Japanese Patent Publications 18588-1858 and 10630-1982. Although these methods can considerably improve the non-aggregation property and crystal stability of red azo pigments, the effects are still insufficient, so as a result of further detailed investigation,
We have found that when a carboxyl group is introduced into the chemical structure of a naphthol AS-based insoluble azo pigment, a pigment dispersant that is particularly effective in dispersing red azo pigments can be obtained. The present inventors have developed an offset ink as described above,
We conducted studies to solve various problems that occur in non-aqueous vehicles such as gravure inks and paints, and invented an azo pigment dispersant that is excellent in practical use. That is, the present invention is an azo pigment dispersant represented by the following general formula (). General formula () Q in the formula: (However, Z represents a benzene ring or a naphthalene ring.) A: represents a saturated alkylene group or arylene group having 1 to 20 carbon atoms, which may be substituted with or without a direct bond or a carboxylic acid amide bond. . M: represents one equivalent of a mono- or divalent cation, such as hydrogen, various metals, or quaternary ammonium salt. X, Y: mutually independent saturated or unsaturated alkyl groups having 1 to 20 carbon atoms, aryl groups, halogen atoms, -NR'R'', -CO', -CONR'R'', -
SO ₂ NR′R″, −O−R′, −NO ₂ , −SO ₂ NR′R″,
where R' and R'' represent a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, or an aryl group; l, m: mutually independent integers of 0 to 2; n: an integer of 1 to 4; It should be noted that the pigment acid splitting agent represented by the general formula () can provide superior effects in small amounts compared to the pigment dispersants shown in Japanese Patent Publications No. 44-18588 and Japanese Patent Publication No. 55-10630. In addition, the pigment dispersant represented by the general formula () has a hydrophobic insoluble azo pigment skeleton as a matrix skeleton,
Because it has a carboxyl group as a polar group, which has lower solubility than a sulfophonic acid group, the pigment particles can be separated from water well, and have the advantages of being easy to wash with water, being soft after drying, and having good redispersibility. be. The pigment dispersant represented by the general formula () will be explained in detail in the production example below, but for example, it is a diazo compound of arylamine having a carboxyl group as a base component or 3-phenylcaribamoyl-3-phenylcaribamoyl having a carboxyl group as a coupler component. It can be easily obtained by using a 2-naphthol compound and coupling it with a diazonium salt of 3-phenylcarbamoyl-2-naphthol and an arylamine, respectively, in a conventional manner. The azo pigment dispersant of the present invention has a particularly favorable effect when used for dispersing azo pigments such as soluble and insoluble azo pigments and condensed azo pigments, but includes phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, perylene/perinone pigment,
Organic pigments such as dioxazine pigments, healthy dye pigments, basic dye pigments, and carbon black,
It can also be used to disperse inorganic pigments such as cadmium red, Bengara, iron black, navy blue, and ultramarine blue. The azo pigment dispersant represented by the general formula () according to the present invention is preferably added in an amount of 0.01 to 30 parts by weight per 100 parts by weight of the pigment. If it is less than 0.01 part by weight, the effect of the pigment dispersant represented by the general formula () cannot be obtained, and even if it is used in excess of 30 parts by weight, the effect of the pigment cannot be obtained. As a method for preparing a pigment composition using the azo pigment dispersant according to the present invention, simply mixing the pigment powder and the powder of the pigment dispersant represented by the general formula () according to the present invention is sufficient to achieve the desired effect. However, the pigment dispersant represented by the general formula ( Add a solution containing the pigment to deposit a pigment dispersant represented by the general formula () on the pigment surface, or
Even better results can be obtained if an intimate mixing method is performed, such as co-dissolving the organic pigment and the pigment dispersant represented by the general formula () in a solvent with strong dissolving power such as sulfuric acid, and co-precipitating it with a poor solvent such as water. can be obtained. Alternatively, it can be added during or after the manufacturing process of printing inks and paints. Furthermore, when the target pigment is an azo pigment, a method usually called mixed coupling is effective. That is, by mixing the required amount of a base or coupler having a carboxyl group with the corresponding base or coupler during the coupling synthesis of pigments, it is possible to obtain a pigment composition that is extremely intimately mixed. The pigment composition thus obtained can be used in offset ink vehicles such as various rosin-modified resins, gravure inks such as lime rosin varnish, polyamide resin varnish, or vinyl chloride resin varnish, nitrocellulose lacquer, amino alkyd resin, etc. When used in air-dry or baked paints, acrylic lacquers, aminoacrylic resin baked paints, urethane resin paints, etc., it has good fluidity such as lower dispersion viscosity and lower manufacturing viscosity than when using pigment alone. At the same time, there are no problems such as color separation or changes in crystals, and the printed matter or coating film has good gloss, so beautiful products can be obtained. An outline of the synthesis method of a typical azo pigment dispersant represented by the general formula () will be described below as a production example. Production Example 1 Acid chloride was synthesized by heating and stirring β-oxynaphthoic acid with an equimolar amount of thionyl chloride in benzene or acetone under reflux for 1 hour, and after the reaction was completed, various amines were added and further under reflux. The mixture was heated and stirred for 1 hour to obtain the following coupler component. <Coupler component having carboxyl group> By diazotizing and coupling various bases to these coupling components, the following azo pigment dispersants were obtained. Production Example 2 Various azo pigment dispersants were obtained by diazotizing the following bases having a carboxyl group by a conventional method and coupling them with various coupler components. <Bases having a carboxyl group>

【formula】

【formula】

【formula】

【formula】

【formula】 Production Example 3 Diazotization and coupling were performed using the carboxyl group-containing coupler component obtained in Production Example 1 and the carboxyl group-containing bases used in Production Example 2 to obtain the following azo pigment dispersant. Production Example 4 Various azo pigment dispersants having carboxyl groups obtained in Production Examples 1, 2, and 3 are dissolved or suspended in neutral or alkaline water, or mixed with a small amount of a polar organic solvent or a hydrophobic organic solvent at the interface. An aqueous solution of mono- or divalent metal ions or an organic amine is added to a system in which the azo pigment dispersant is dissolved or suspended in an emulsion containing an activator, heated and stirred, filtered, washed with water, and dried to produce the following. An azo pigment dispersant was obtained. Examples and comparative examples will be described below. The chemical structure of the azo pigment dispersant indicated by Alphabet corresponds to that shown in the production example.
The mixing ratio is expressed as a weight ratio of (pigment:dispersant of the present invention). Comparative Examples and Examples 1 to 15 Gravure Ink Test Gravure vinyl chloride varnish was coated with various pigments alone (comparative examples) or mixtures of various pigments and various azo pigment dispersants shown in Production Examples 1 to 4, each having a pigment content of 10 % or 25% (for inorganic pigments) to prepare gravure inks and examine their viscosity. The results are shown in Table 1, and the material according to the present invention has excellent fluidity. Furthermore, excellent results were obtained in terms of color clarity, coloring power, and gloss of printed matter printed with the gravure ink.

【table】

[Table] Examples 16 to 36 Various pigments alone (comparative example) or mixtures of various pigments and each azo pigment dispersant shown in Production 1 to 4 were added to aminoalkyd resin varnish for baking paints.
Paints were prepared by blending the pigments at a pigment content of 6% or 25% (in the case of inorganic pigments), and their viscosity was measured. The results are shown in Table 2. The aminoalkyd paints according to Examples had excellent fluidity and crystal stability, and also had excellent color beauty, coloring power, and gloss in the coating film. Furthermore, the storage stability was also excellent, with little change in the degree of viscosity increase.

【table】

[Table] Regarding dispersion stability, we will also compare the performance of color separation stability, which is a particular problem in applications. A light-colored paint is obtained by cutting the paint shown in the examples in Table 2 using a titanium oxide base paint prepared in advance with aminoalkyd varnish so that the ratio of pigment to titanium oxide is 1/10. The light-colored paint was further diluted with xylene, adjusted to 30 seconds (25°C) using a food cup No. 4, and injected into a test tube to observe changes in the glass wall. Table 3 shows the results.

[Table] In all cases, the products according to the present invention show excellent results. Examples 37-51 CIPigment on nitrocellulose lacquer
Blue15 alone (comparative example 1) or CIPigment
Table 4 shows the viscosity of a paint prepared by blending a mixed pigment composition of Blue 15 and azo pigment dispersant u so that the pigment content was 5.5%. Similarly, Table 4 shows the test results regarding the viscosity in a nitrocellulose slugger using combinations of other pigments and various compounds according to the present invention. In all cases, the composition according to the present invention showed excellent results in terms of fluidity, gloss in the developed coating film, clarity of color tone, and tinting power.

[Table] Table 5 shows the results of storing the paints shown in the examples in Table 4 at 50°C for 3 months and measuring the viscosity thereafter.

【table】

[Table] As is clear from the results in Table 5, all the products according to the present invention exhibit excellent storage stability. Example 52 Aminoacrylic baking paint CI on aminoacrylic baking paint varnish
Pigment Orange36 alone (comparative example) or CI
Pigment Orange36 and azo pigment dispersant d
When the fluidity of paints prepared by adjusting the pigment content to 6% from a 90:10 mixed pigment composition was compared, the paint according to the present invention showed significantly superior results. In addition, even in paints prepared by cutting the above-prepared paint using an aluminum paint base prepared in advance with aminoacrylic paint varnish so that the ratio of pigment to aluminum is 1/5, the paint according to the present invention has a significantly clear color tone and excellent gloss. showed that. Example 53 Urethane paint varnish A urethane paint varnish containing CIPigment Red 146 alone (comparative example) or a 90:10 mixed pigment composition of CIPigment Red 146 and azo pigment dispersant a was adjusted so that the pigment content was 10%. When the fluidity of the paints and the state of the developed paint film were compared, it was found that the paint according to the present invention had excellent fluidity and also excellent color tone and gloss of the developed paint film. Example 54 Rosin-modified phenolic resin offset ink Rosin-modified phenolic resin offset ink varnish with CIPigment Red53 alone (comparative example) or CIPigment Red57 and azo pigment dispersant c.
Offset inks were prepared using mixed pigment compositions in a ratio of 85:15 so that the pigment content was 30%, and the fluidity of the inks was compared using a parallel plate viscometer. It showed excellent results. In addition, printed matter according to the present invention is
It showed excellent results in terms of color clarity, tinting strength, and transparency.

Claims (1)

[Claims] 1. A pigment dispersant represented by the following general formula (). General formula () Q in the formula: (However, Z represents a benzene ring or a naphthalene ring.) A: represents a saturated alkylene group or arylene group having 1 to 20 carbon atoms, which may be substituted with or without a direct bond or a carboxylic acid amide bond. . M: represents one equivalent of a mono- to divalent cation. X, Y: mutually independent saturated alkyl groups having 1 to 20 carbon atoms, aryl groups, halogen atoms, -
NR′R″, −CON′RR″, −SO ₂ NR′R″, −O−R′,
−NO ₂ , −NR′COR″, where R′ and R″ are hydrogen atoms,
a saturated or unsaturated alkyl group having 1 to 20 carbon atoms,
Represents an aryl group. l, m: Represent mutually independent integers of 0 to 2. n: represents an integer from 1 to 4.