Preparation of red pigment for liquid printing ink

Abstract

The invention relates to a method for preparing a yellow pigment for liquid ink. The method comprises the following steps of : reacting 1 portion of 2-amino-5-toluene sulphonic acid with 0.32 portion of sodium nitrite to form a diazo component in 470 portions of ice water and 1.5 portions of thirty to thirty-two percent hydrochloric acid medium; coupling the diazo component with 1.1 portions of 2- hydroxide-3-naphthoic acid in water medium when the PH value is between eight and ten, filtering the diazo liquid, adding the filtered diazo liquid 2-hydrodxy-3- naphthoic acid slowly with stirring within one hundred and twenty and one hundred and fifty minutes and keeping the temperature between fifteen and twenty DEG C and the PH valve between eight and ten and stirring for hundred and twenty and one hundred and fifty minutes; during post treatment of red pigment, adding 0.3-0.5 portion of metal salt for lake and 0.01-0.05 portion of surface active agent, heating to fifty to eighty DEG C; stirring for thirty to sixty minutes, allowing absolute-SO3H and-COOH to react with metal salt to generate red lake pigment; filtering the pigment, cleaning the pigment with water and conducting routine pigmentation treatment to a filter mass after completion. The preparation method has excellent solvent resistance and storage stability life in polyurethane system ink. The method is simple in technology and remarkable in effect, effectively improving the product quality.

Description

technical field [0001] The invention belongs to the field of organic pigments, and relates to a preparation method of ink pigments, in particular to a preparation method of liquid ink red pigments. Background technique [0002] At present, C.I Pigment Red 48:1 has the characteristics of bright color, large transparency, high tinting strength, light fastness, and stable physical and chemical indicators. Therefore, it is widely used in plastic coloring, coating and printing ink. However, with the development of packaging printing technology, it is difficult to apply to liquid ink. Such as poor solvent resistance, poor dispersion stability, etc. Causes the defects of poor ink rheology and poor storage stability. This makes it impossible to produce solvent-based inks in the application of C.I pigment red 48:1 hue ink varieties. Specifically, when C.I Pigment Red 48:1 is used in polyurethane system and acrylic system, the ink has high viscosity and poor rheology, and its colo...

AI Technical Summary

Problems solved by technology

However, with the development of packaging printing technology, it is difficult to apply to liquid ink

Such as poor solvent resistance, poor dispersion stability, etc.

Poor ink rheology and poor storage stability

This makes it impossible to produce solvent-based inks in the application of C.I pigment red 48:1 hue ink varieties

Specifically, when C.I Pigment Red 48:1 is used in polyurethane system and acrylic system, the ink has high viscosity and poor rheology, and its chromatic light wave shifts, resulting in the disadvantages of not bright colors and low coloring concentration

On the one hand, the transfer performance of the ink on the printing press is poor, and on the other hand, the printed matter loses the ideal effect