JPS58160364A - Prepartion of copper phthalocyanine pigment with instability to solvent for intaglio printing ink - Google Patents

Abstract

PURPOSE:To prepare the titled pigment with improved wipe-off characteristics when blended in large amts. in intaglio printing inks, by adding water to a soln. of copper phthalocyanine dissolved in conc. sulfuric acid and heat-treating the resulting soln., followed by hydrolysis. CONSTITUTION:Copper phthalocyanine is dissolved in 7-10 times by wt., based on the amt. of phthalocyanine, of conc. sulfuric acid. Water is added to the resulting soln. to adjust the concn. of sulfuric acid to 71-90wt% and the mixt. is heat-treated at 50-80 deg.C and then hydrolyzed by the addn. of a large amt. of water. The precipitate of the mixt. is filtered and dried to yield a copper phthalocyanine pigment with instability to solvents for intaglio printing inks having a specific surface area of 20-40m<2>/g.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a solvent-labile steel phthalocyanine pigment (hereinafter referred to as αm cu -PC), which has significantly improved wiping properties when incorporated in a large amount in an intaglio printing ink.

In intaglio printing, the line structure of the plate surface is concave relative to the surface of the plate material, so it is difficult to apply ink only to the line areas, unlike other printing plate types.

Therefore, after first applying ink to the entire surface of the plate, it is necessary to wipe off the ink from the non-printing areas using various methods before printing. Since such intaglio printing is mainly used for printing banknotes and other securities, inks with poor wiping properties will contaminate the printed matter, so ink with particularly good wiping properties is required.

Copper phthalocyanine pigments are pigments with excellent light, heat, and chemical resistance, but they have poor wiping properties when used in large amounts in intaglio printing inks.
-Pc was extremely poor.

The α-type Cu-Pc industrial manufacturing method includes an acid paste method in which crude steel phthalocyanine is dissolved in concentrated sulfuric acid of 95 parts by weight or more, and this is poured into a large amount of water to reprecipitate fine particles. An acid slurry method is generally known in which fine particles are obtained by hydrolyzing the sulfate obtained in a weight range of ~80% by weight. In the acid slurry method, coloring power is important, so the processing temperature is low, at most 40°C.
It was about. α-type CuP obtained in this way
c has a specific surface area of 75 to 120 rr? /l, and therefore, although the coloring power is high, the fluidity is extremely poor, which causes poor wiping characteristics in intaglio printing inks.

As a method for improving wiping characteristics, Japanese Patent Application Laid-Open No. 56-86978
The publication describes a method for obtaining an unstable copper phthalocyanine pigment by dissolving copper phthalocyanine in concentrated sulfuric acid, then adjusting the amount to 55 to 705 to 70 parts by weight, performing heat treatment, and then hydrolyzing it. .

However, in this method, the heat treatment temperature is 80 to 110°C.
The temperature is extremely high, and the treatment time is extremely short at 1 to 8 hours, which is not sufficient to industrially obtain uniform particles.

Therefore, the present inventors conducted extensive research on improving the wiping characteristics of intaglio printing ink, and as a result, they arrived at the present invention.

That is, in the present invention, copper phthalocyanine is dissolved in concentrated sulfuric acid, the sulfuric acid concentration is adjusted to 71 to 901 to 90 parts by weight, heat treatment is performed, and then hydrolyzed to obtain a specific surface area of 20 parts by weight.
~40tT? α-type Cu for intaglio printing ink characterized by obtaining a pigment of /y (BET method using nitrogen adsorption)
- A method for producing Pc.

If the specific surface area exceeds 40 i/l, conventional α type C
No significant improvement in wiping properties was observed compared to u-Pc (specific surface area 75-120 m"/f), and
rr? If it is less than /, the tinting strength and color purity are significantly lowered, which is undesirable.

Next, the method of the present invention will be explained in more detail.

The concentration of sulfuric acid is 71 to 901 to 90 parts by weight.The amount used is not particularly limited, but is 6 to 12 times the weight of copper phthalocyanine in order to facilitate the stirring operation. In the present invention,
Copper phthalocyanine is first added to concentrated sulfuric acid. Then, after adjusting the sulfuric acid concentration to a predetermined value, heat treatment is performed. It was observed that the growth of the crystals at this time was highly dependent on temperature, and that they grew with the processing time, and the longer the time, the more uniform the particles were, and the smaller the specific surface area. Therefore, uniform particles have a specific surface area of 20 to 40 rr? In order to obtain /f, the temperature is preferably 50-80°C and the time is preferably 8-4 hours. 80
If it exceeds ℃, 20 to 40 tr in 1 to 2 hours? /l
particles were obtained, but were significantly non-uniform.

Furthermore, compared to the method of JP-A-56-869711-, the method of the present invention has much better uniformity of the particles obtained, which is presumably due to the milder treatment temperature and longer treatment time. Ru.

The heating method may be external heating, but it is also possible to effectively utilize the dilution heat of sulfuric acid. For this purpose, copper phthalocyanine is dissolved in 7 to 10 times its weight of concentrated sulfuric acid, and the sulfuric acid concentration is adjusted to 71% by weight. ~901~90 parts by weight of sea urchin by dropping water or injecting it into water to bring the temperature to 50~80%
Adjust the temperature accordingly.

(5) After heat treatment is performed in this manner, hydrolysis is performed.

Hydrolysis involves dropping a large amount of water or injecting it into multiple layers of water, but apart from after heat treatment,
It may be poured into a large amount of water; in this case, 71 to 901
Since ~90 parts by weight are recovered, it is possible to reuse it as is. After hydrolyzing in this way, it is separated by i by a conventional method and has a specific surface area of 20 to 40 tr? An α-type-Cube having /f is obtained.

The α-type Cu-Pc particles obtained by the present invention have an extremely small specific surface area of 20 to 40 nitrates, and have a specific surface area of 75 to 120 tr? It was confirmed that the fluidity of the intaglio printing ink was much better when compared with that of /f, and as a result, the wiping properties of the ink were significantly improved.

The present invention will be explained in more detail in the following examples.

In the examples, parts and parts are by weight.

(6) Example 1 20 parts of crude steel phthalocyanine is dissolved in 160 parts of concentrated sulfuric acid by stirring at room temperature for 2 hours. Then, 41 parts of water was added dropwise to bring the sulfuric acid concentration to 78%, and the temperature was raised to 80° C., and the mixture was stirred at this temperature for 7 hours. Next, the mixture is poured into 1,000 parts of water, stirred at 50 to 60°C for 1 hour, hydrolyzed, filtered, washed with water, and dried.

9.8 parts of α-type Cu-Pcl were obtained. The specific surface area of this product is 84. It was Otl/l.

Example 2 80 parts of crude steel phthalocyanine are dissolved in 28° parts of concentrated acid at room temperature. Add 45 parts of water dropwise to bring the sulfuric acid concentration to 82.0'
By setting A, the temperature is raised to 68° C. and stirred at this temperature for 5 hours.

The resulting cake was then filtered, and the resulting cake was dissolved in 500 parts of water.
Hydrolysis is carried out by stirring at 60° C. for 1 hour. Then, it is filtered, washed and dried.

29 parts of α-type Cu-Pa were obtained.

The specific surface area of this material was 29.5 m''/f.

Examples 3 to 8 Example 1 except that after dissolving in concentrated sulfuric acid, the amount of water dropped was changed and the sulfuric acid concentration and heat treatment temperature and time were changed as shown in Table 1.
The same operation as above was performed to obtain the following α-CuPc.

Table-1 Application Example α-type Cu-P obtained in Examples 1 to B and 6.8
Intaglio printing ink suitability was evaluated between JP-A-56-869788 and those obtained by the acid paste method as a comparative example.

Table 2 shows the test results, and Table 3 shows the ink formulation.

It was confirmed that the product obtained according to the present invention had excellent fluidity and significantly improved wiping properties. Further, the decrease in hue due to the reduction in the specific surface area was extremely small and did not cause any problems in use.

Table 2 Test results (Note) 1) Measured value by inclined plate viscometer (Poise/80℃
) 2) Results from the Printing Bureau type intaglio printing aptitude tester ◎ Good
Good ○ Fair Δ Slightly poor ) 5) Commercial product Sumikablint Cyanine Blue RX produced by acid paste method (product of Sumima Kagaku Kogyo Co., Ltd., specific surface area was 87.0%) Table 8 Composition of intaglio printing ink (Note) 6) Shiraishi Kogyo ( Co., Ltd. products

Claims (2)

[Claims] (1) Copper phthalocyanine is dissolved in concentrated sulfuric acid, then the sulfuric acid concentration is increased to 71 to 90% by weight, and then heat treated and then hydrolyzed to a specific surface area of 20 to 40 r.
r? A method for producing a solvent-labile steel phthalocyanine pigment for intaglio printing ink, characterized in that a pigment of /l is obtained. (2) The manufacturing method according to claim 1, wherein the heat treatment is performed at a temperature of 50 to 80°C.