JP2773263B2 - Azo lake pigment surface treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention, when used in gravure printing ink, flexographic printing ink, etc., has good soaring suitability, and
The present invention relates to a surface treatment method for an azo lake pigment which can provide an azo lake pigment excellent in clarity, gloss, density, transparency and the like of a printed matter.

[Prior Art] Conventionally, azo lake pigments have been widely used for coloring agents such as synthetic resins and rubbers, and paints. One of the uses of such azo lake pigments is as a colorant for printing inks, for example, as a colorant for gravure printing inks or flexographic printing inks.

However, when water is mixed into the printing ink using the azo lake pigment due to condensation of moisture in the air, the viscosity of the ink increases or gelation occurs. However, there is a problem that it often becomes unusable. Further, printed matter using the printing ink mixed with water as described above has various disadvantages such as a decrease in gloss, a decrease in density, and opacity.

The phenomenon that occurs when water is mixed into the printing ink is called souring, and the performance of the azo lake pigment with respect to this soaring is called soaring suitability. As an azo lake pigment that is less likely to cause soaring, a mono azo lake pigment surface-treated with rosin and a metal salt has been proposed (JP-A-63-120764). When used as gravure printing ink or flexographic printing ink,
There is a problem that the gloss and the density of the printed matter are reduced.

The present invention has been made in view of the above circumstances, and when used as a coloring agent for gravure printing or flexographic printing ink, soaring is unlikely to occur, and the printed matter has excellent properties such as gloss, density, and transparency. It is an object of the present invention to provide a method for treating the surface of an azo lake pigment from which an azo lake pigment is obtained.

"Means for Solving the Problems" The present invention relates to an alkaline suspension obtained by dispersing an azo lake pigment in water, adding 3 to 20 parts by weight of a water-soluble aluminum salt to 100 parts by weight of the azo lake pigment. The above problem is solved by providing a surface treatment method of an azo lake pigment used for a gravure printing ink or a flexographic printing ink, wherein the surface treatment is performed so that the pH after the treatment is less than 7. .

Hereinafter, the surface treatment method of the azo lake pigment of the present invention will be described in detail.

In the surface treatment method for an azo lake pigment of the present invention, first, after a coupling reaction in water, a suspension of the azo lake pigment obtained by lake formation is heated or cooled as necessary. The pH of the suspension is adjusted with hydrochloric acid, caustic soda, or the like as necessary so that the pH after the treatment is less than 7.

The surface treatment of the azo lake pigment is carried out by adding an aluminum salt to the suspension thus adjusted to form a treatment liquid and, if necessary, stirring while heating.
The temperature at the time of stirring can be any temperature depending on the requirement of transparency of the pigment and the like, but it is preferable to stir at 40 to 90 ° C. The stirring time for this surface treatment is 5 minutes or more, preferably in the range of 5 minutes to 30 minutes, and the effect does not change even if the stirring is performed for more than 30 minutes. In the present invention, the pH of the treatment liquid after the surface treatment needs to be less than 7, and if the pH is within the range of 3 to 6, the effect of improving the suitability for soaring is high, and the gloss, the density, and the transparency are improved. This is preferable since printed matter excellent in properties and the like can be obtained, and furthermore, problems such as treatment of wastewater having a treatment liquid pH after surface treatment and rusting of equipment and the like hardly occur.

When surface-treating an azo lake pigment marketed as a product, first, this azo lake pigment is dispersed in water to form a suspension. Next, the temperature and pH of this suspension are adjusted in the same manner as in the suspension of the azo lake pigment after lake formation described above. An aluminum salt is added to the suspension thus adjusted, and the surface treatment of the azo lake pigment is performed in the same manner as described above.

The treatment liquid after the surface treatment is filtered, the residue is washed with water, and then dried at a predetermined temperature to obtain the surface-treated azo lake pigment obtained by the present invention.

The aluminum salt used in the present invention may be any water-soluble salt, for example, inorganic aluminum salts such as aluminum chloride, aluminum sulfate, aluminum nitrate and aluminum phosphate, and organic aluminum salts such as aluminum formate and aluminum acetate. However, in the present invention, aluminum chloride and aluminum sulfate are preferred. In addition, these aluminum salts may contain water.

The concentration of the aluminum salt in the treatment liquid is preferably in the range of 3 to 20 parts by weight based on 100 parts by weight of the azo lake pigment. Within this range, the azo lake pigment will have sufficient soaring suitability and can prevent an increase in viscosity immediately after ink preparation.

As the azo lake pigment before surface treatment used in the present invention, for example, CI Pigment Red 48: 1, also 4
8: 2, 48: 3, 48: 4, 49: 1, 49: 2, 49: 3, 52: 1, 52: 2, 53:
1, 53: 2, 57: 1, 58: 1, 58: 2, 58: 3, 60: 1, 63: 1, 63:
2, 68, 151, 247; and azo lake pigments such as CI Pigment Yellow 133 and 169.

Preparation of gravure and flexographic printing inks using the azo lake pigment surface-treated according to the present invention is carried out by a conventional method, and there is no particular limitation on the preparation method, materials used and the like.

Examples of the resin used for the gravure and flexographic printing inks include nitrocellulose resin, maleic acid resin, chlorinated propylene resin, polyamide resin, urethane resin, ethylene-vinyl acetate copolymer resin, and nitro resin. Cellulose-based resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, chlorinated rubbers, cyclized rubbers, epoxy resins and the like can be mentioned.

"Examples" Hereinafter, the surface treatment method of the azo lake pigment of the present invention will be specifically described with reference to Examples, Comparative Examples, and Test Examples. The parts and percentages in the following examples are on a weight basis (however, gloss values are excluded).

(Example 1) After 100 parts of 2-amino-5-methylbenzenesulfonic acid was dispersed in 1500 parts of water, 105 parts of 20% hydrochloric acid was added, and 124 parts of 30% sodium nitrite was added dropwise while keeping the temperature at 5 ° C or less, and diazo was added. It has become.

Next, 102 parts of 2-hydroxy-3-naphthoic acid was added to 300 parts of water.
After dispersing in 0 parts, 95 parts of a 48% aqueous solution of caustic soda was added and dissolved, and the mixture was cooled to 5 ° C. or lower.

The above diazo solution was dropped into the coupler solution with stirring, and a coupling reaction was performed. Then, 200 parts of a 10% tall oil rosin soda aqueous solution was added, the mixture was stirred for 30 minutes, and 100 parts of calcium chloride hydrate was further added to 500 parts of water. Add the dissolved solution and add 60
After stirring for minutes, the lake formation reaction was completed.

A suspension in water containing 100 parts of the azo lake pigment (CI Pigment Red 57: 1) thus obtained was heated to 80 ° C., and the pH was adjusted to 9.0 by adding a 10% aqueous hydrochloric acid solution. A solution prepared by dissolving 6 parts of salt in 50 parts of water was added, and the mixture was stirred at 80 ° C. for 30 minutes and filtered while hot. Filtrate pH
Was 5.2. The residue is washed with water and dried at 90 ° C. to obtain a bluish-red pigment (hereinafter, referred to as pigment (I)).
101.3 parts were obtained.

(Example 2) An azo lake pigment (CI
Pigment Red 57: 1) A suspension in water containing 100 parts at 80 ° C
After heating to pH 9.0 and adjusting the pH to 9.0, a solution of 20 parts of aluminum sulfate dissolved in 100 parts of water was added, and the mixture was stirred at 60 ° C. for 30 minutes and filtered while hot. The filtrate had a pH of 3.2, and the residue was washed with water and dried at 90 ° C. to obtain 101.7 parts of a bluish red pigment (hereinafter, referred to as pigment (II)).

(Comparative Example 1) An azo lake pigment (CI
Pigment Red 57: 1) A suspension in water containing 100 parts at 80 ° C
Then, a solution prepared by dissolving 6 parts of aluminum chloride hexahydrate in 50 parts of water was added, and the mixture was stirred at 80 ° C. for 30 minutes and filtered while hot. The pH of the filtrate was 10.6. After washing the residue with water, 90 ° C
To obtain 103.1 parts of a bluish red pigment (hereinafter, referred to as pigment (I ')).

(Comparative Example 2) An azo lake pigment (CI
Pigment Red 57: 1) 80 suspensions in water containing 100 parts
The mixture was stirred while heating at 30 ° C. for 30 minutes, filtered while hot, and the residue was washed with water and dried at 90 ° C. to obtain 100 parts of a bluish red pigment (hereinafter referred to as pigment (II ′)). Obtained.

(Example 3) After dispersing 118 parts of 2-amino-4-chloro-5-methylbenzenesulfonic acid in 1500 parts of water, 105 parts of 20% hydrochloric acid was added, and while maintaining the temperature at 5 ° C or lower, 124 parts of sodium sulfite at 30 ° C. Was added dropwise to perform diazotization.

Next, 102 parts of 2-hydroxy-3-naphthoic acid was added to 300 parts of water.
After dispersing in 0 parts, 95 parts of a 48% aqueous solution of caustic soda was added and dissolved, and the mixture was cooled to 5 ° C. or lower.

The above diazo solution was added dropwise to this coupler solution with stirring, and after a coupling reaction, 200 parts of a 10% aqueous solution of rosin soda in tall oil was added, followed by stirring for 30 minutes, and 100 parts of calcium chloride hydrate was dissolved in 500 parts of water. The liquid was added, and the mixture was stirred for 60 minutes to complete the lake formation reaction.

A suspension in water containing 100 parts of the azo lake pigment (CI Pigment Red 48: 2) thus obtained was heated to 80 ° C., and the pH was adjusted to 10.5 by adding a 10% aqueous hydrochloric acid solution. A solution prepared by dissolving 9 parts of salt in 50 parts of water was added, and the mixture was stirred at 80 ° C. for 30 minutes and filtered while hot. Filtrate pH
Was 4.6. The residue was washed with water and dried at 90 ° C. to obtain 101.7 parts of a bluish red pigment (hereinafter, referred to as pigment (III)).

(Comparative Example 3) An azo lake pigment (CI
Pigment Red 48: 2) 80 suspensions in water containing 100 parts
The mixture was stirred while heating at 30 ° C. for 30 minutes, filtered while hot, and the residue was washed with water and dried at 90 ° C. to obtain a bluish red pigment (hereinafter, referred to as pigment (III ′)).

(Test Example 1) Each of the pigments (I), (II), (I ') and (II') obtained in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 was 10%.
Parts, 30 parts of nitrocellulose gravure varnish, solvent (toluene: ethyl acetate: isopropyl alcohol = 6: 2: 2) 4
0 parts and 150 parts of steel beads were put in a container, and after kneading with a paint conditioner for 60 minutes, 40 parts of a polyamide gravure varnish was added to prepare a gravure printing ink.
The ink was spread on a film, and the density, transparency, and gloss were measured. The density was measured by a Gretag densitometer (reflection densitometer), and the gloss was measured by a gloss meter (60 °). The transparency was evaluated by placing the ink-coated film on black paper and setting Comparative Example 2 as a standard (3: standard). (1: extremely opaque, 2: opaque, 3: standard, 4: transparent, 5: extremely transparent) Also, dilute the prepared ink with a solvent (toluene: ethyl acetate: isopropyl alcohol = 6: 2: 2), After adjusting to 18 seconds with Zahn Cup No. 3, 2 parts of water was added to 100 parts of the diluted ink, stirred, allowed to stand for one day, and the viscosity was measured again with Zahn Cup. A series of these tests is called a soaring test, and the number of Zahn cup seconds after standing for one day is called a soaring viscosity. As the soaring viscosity is smaller than the initial viscosity (18 seconds), the soaring suitability is better. Also, after spreading the ink after this soaring test on the film,
The gloss was measured. As the gloss after the soaring test is smaller than the initial gloss, the lower the gloss is, the better the soaring suitability is.

 Table 1 shows the test results.

As is clear from Table 1, Examples 1 and 2
The pigments (I) and (II) obtained from Comparative Examples 1 and 2 are superior to the pigments (I ') and (II') obtained from Comparative Examples 1 and 2 in gloss, density and transparency. Further, no increase in the soaring viscosity is observed, and the gloss of the printed matter hardly decreases even after the soaring test.

(Test Example 2) 15 parts each of the pigments (I) and (II ') obtained in Example 1 and Comparative Example 2, nitrocellulose gravure varnish 45
Parts, 30 parts of a solvent (toluene: ethyl acetate: isopropyl alcohol = 2: 2: 1) and 300 parts of steel beads are put in a container, and after being kneaded with a paint conditioner for 30 minutes, 60 parts of nitrocellulose gravure varnish is added. To prepare a gravure printing ink.

In the same manner as in Test Example 1, this ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

(Test Example 3) 15 parts of each of the pigments (I) and (II ') obtained in Example 1 and Comparative Example 2, 75 parts of urethane varnish, solvent (methyl ethyl ketone: toluene: isopropyl alcohol = 5: 3:
2) Put 30 parts and 300 parts of steel beads in a container, and after mixing for 30 minutes with a paint conditioner, urethane varnish 30
Parts and 30 parts of a solvent were added to prepare a gravure printing ink.

Hereinafter, in the same manner as in Test Example 1, this ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

(Test Example 4) 10 parts of each of the pigments (I) and (II ') obtained in Example 1 and Comparative Example 2, 60 parts of cyclized rubber, 30 parts of toluene, and 200 parts of steel beads were put in a container, and the mixture was applied to a paint conditioner. For 30 minutes to produce a gravure printing ink.

In the same manner as in Test Example 1, this ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

(Test Example 5) A gravure printing ink was produced in the same manner as in Test Example 1, using the pigments (III) and (III ') obtained in Example 3 and Comparative Example 3.

In the same manner as in Test Example 1, this ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

(Test Example 6) A gravure printing ink was produced in the same manner as in Test Example 4, using the pigments (III) and (III ') obtained in Example 3 and Comparative Example 3.

In the same manner as in Test Example 1, the ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

(Test Example 7) Each of the pigments (I), (III), (II ') and (III') obtained in Example 1, Example 3, Comparative Example 2 and Comparative Example 3
15 parts, nitrocellulose-based flexonis 80 parts, solvent (ethanol: ethyl acetate: isopropyl alcohol = 1: 1:
2) 60 parts and 300 parts of steel beads were put in a container, and the mixture was kneaded with a paint conditioner for 30 minutes to prepare an ink for flexographic printing.

In the same manner as in Test Example 1, this ink was spread on a film, the gloss was measured, and a soaring test was performed.

 Table 2 shows the results.

As is apparent from Table 2, Examples 1 and 3 were used.
Of the pigments (I) and (III) obtained by Comparative Example 2 and the pigments (II ′) and (III ′) obtained by Comparative Example 3 did not show an increase in the soaring viscosity, and even after the soaring test. The gloss of the printed matter is hardly reduced.

[Effects of the Invention] As described above, the present invention relates to an alkaline suspension obtained by dispersing an azo lake pigment in water, by adding 3 to 20 parts by weight of a water-soluble aluminum salt to 100 parts by weight of the azo lake pigment. And the surface is treated so that the pH after the treatment is less than 7.
When the azo lake pigment obtained by the present invention is used for gravure printing ink or flexographic printing ink, it is possible to provide a printed matter having good soaring suitability and excellent in gloss, density, transparency and the like.

Claims (4)

(57) [Claims] 1. An alkaline suspension obtained by dispersing an azo lake pigment in water is added with 3 to 20 parts by weight of a water-soluble aluminum salt based on 100 parts by weight of the azo lake pigment, and the pH after the treatment is less than 7. A surface treatment method for an azo lake pigment used in a gravure printing ink or a flexographic printing ink, wherein the surface treatment is performed so as to be as follows. 2. The method for surface treating an azo lake pigment according to claim 1, wherein the pH after the treatment is from 3 to 6. 3. The method for surface treating an azo lake pigment according to claim 1, wherein the aluminum salt is aluminum chloride and / or aluminum sulfate. 4. The method of claim 1, wherein the azo lake pigment before the treatment is CI Pigment Red 57: 1 and / or CI Pigment Red 48: 2.