A method for improving the dispersing properties of cellulases on organic pigments

Abstract

The application discloses a method for improving the dispersing performance of cellulase on organic pigments, characterized by the following process: (1) cellulase and NaOH with a mass ratio of 5:1 are added into deionized water for fully dissolving, 60% of the cellulase in mass is slowly added into the deionized water at 40 DEG C, and the pH value of the system is maintained at 9-10 by using NaOH solution, after the dropwise addition is completed, the temperature is increased to 50 DEG C for continuously reacting for 2 hours, then hydrochloric acid is added for adjusting the pH value to 1-2, the reaction product is precipitated and washed by deionized water until neutral, and vacuum drying is carried out to obtain modified cellulase; (2) organic pigments, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 are added into deionized water, and ultrasonic treatment is carried out for 30 minutes to obtain a pigment dispersion. The cellulase is modified by using the method, and the modified cellulase can further improve the dispersing performance on organic pigments.

Description

TECHNICAL FIELD

[0001] The application relates to a method for improving the dispersing performance of cellulase on organic pigments and belongs to the technical field of textile printing and dyeing. BACKGROUND

[0002] Water-based organic pigments can be used for printing and dyeing processing of various textiles, have advantages such as short process flow and small water consumption, and are one of important technologies for promoting sustainable development of the textile printing and dyeing industry. Organic pigments have strong hydrophobicity and are difficult to be uniformly and stably dispersed in a water-based medium. Usually, the organic pigments need to be physically or chemically dispersed so as to form a stable primary particle dispersion to be successfully applied. Physical dispersion utilizes high-intensity shearing or impact force to break and uniformly disperse pigment particles, mainly including grinding, ultrasonic and gas (liquid) flow crushing and the like. Chemical dispersion mainly includes methods such as chemical modification, grafting and coating according to the properties of pigment particles to treat the pigment so as to have different surface properties from the original. Compared with the chemical dispersion method, the physical dispersion method is simpler to operate and is more widely applied.

[0003] In the physical dispersion process of the organic pigment, a certain amount of dispersant needs to be added. The dispersant can be adsorbed to the surface of the pigment to produce charge repulsion and steric hindrance effect, prevent the pigment particles from re-aggregating, and thus keep a stable suspension state. The dispersants used in the water-based pigment system mainly include three types of inorganic, organic small molecule and high molecular dispersants. The inorganic dispersants mainly include polyphosphate, silicate and carbonate and the like; the organic small molecule dispersants mainly are anionic, cationic and non-ionic surfactants; and the high molecular dispersants mainly are polyelectrolyte and natural polymer and the like. In recent years, the application of the natural polymer dispersant has attracted attention, and natural polymer substances such as casein, gelatin, lecithin, chitosan, sodium alginate and cellulase and modified derivatives thereof are used for organic pigment dispersion by researchers and certain effects are obtained.

[0004] Cellulase is a general term of enzymes for catalyzing the hydrolysis of cellulose, mainly composed of endoglucanase, exoglucanase and beta-glucosidase. The chemical nature of cellulase is protein, which presents certain colloid characteristics in an aqueous solution. In the physical crushing process such as ultrasonic, the cellulase can be combined to the surface of the organic pigment, and due to the typical amphoteric property of the enzyme protein, the electric property of the organic pigment dispersion can be regulated, which is beneficial to obtain a wider application range. SUMMARY

[0005] The application aims to provide a method for improving the dispersing performance of cellulase on organic pigments, in which oleoyl chloride is used as an acylating agent to graft and modify the cellulase, and the modified cellulase can further improve the dispersing capacity on the organic pigment.

[0006] The application comprises the following process:

[0007] (1) Cellulase and NaOH with a mass ratio of 5:1 were added into deionized water to be dissolved thoroughly, and oleoyl chloride accounting for 60% of the mass of cellulase was slowly added at 40°C, and the pH value of the system was maintained at 9-10 by NaOH solution, after the dropwise addition was completed, the temperature was increased to 50°C to continue the reaction for 2 hours, then hydrochloric acid was added to adjust the pH value to 1-2, the precipitate of the reaction product was separated out and washed with deionized water until neutral, and vacuum drying was performed to obtain modified cellulase;

[0008] (2) Organic pigment, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water, and ultrasonic treatment was performed for 30 minutes to obtain a pigment dispersion.

[0009] Cellulase and NaOH with a mass ratio of 5:1 were added into deionized water to be dissolved thoroughly, and oleoyl chloride accounting for 60% of the mass of cellulase was slowly added at 40°C, and the pH value of the system was maintained at 9-10 by NaOH solution, after the dropwise addition was completed, the temperature was increased to 50°C to continue the reaction for 2 hours, in this process, oleoyl chloride would be introduced into the carbon chain by acylation reaction with the amino group on the cellulase molecule, so that the performance of the enzyme protein was changed. Then, hydrochloric acid was added to adjust the pH value to 1-2, the precipitate of the reaction product was separated out and washed with deionized water until neutral, and vacuum drying was performed to obtain modified cellulase. The obtained modified cellulase can disperse organic pigment in water. Organic pigment, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water, and ultrasonic treatment was performed for 30 minutes to obtain a pigment dispersion. Due to the optimized structure, the modified cellulase can better disperse the organic pigment into the aqueous medium. DETAILED DESCRIPTION

[0010] The application will be further illustrated by examples.

[0011] Example 1

[0012] (1) Cellulase and NaOH with a mass ratio of 5:1 were added into deionized water to be dissolved thoroughly, and oleoyl chloride accounting for 60% of the mass of cellulase was slowly added at 40°C, and the pH value of the system was maintained at 9-10 by NaOH solution, after the dropwise addition was completed, the temperature was increased to 50°C to continue the reaction for 2 hours, then hydrochloric acid was added to adjust the pH value to 1-2, the precipitate of the reaction product was separated out and washed with deionized water until neutral, and vacuum drying was performed to obtain modified cellulase;

[0013] (2) Organic pigment yellow, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water, and ultrasonic treatment was performed for 30 minutes to obtain a pigment dispersion.

[0014] Comparative Example 1

[0015] The organic pigment yellow, cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water, and treated under the same conditions as in Example 1 to obtain a pigment dispersion.

[0016] It was tested that the average particle size of the pigment yellow dispersion obtained in Example 1 was 408 nm, while the average particle size of the pigment yellow dispersion obtained in Comparative Example 1 was 2674 nm, indicating that the modified cellulase had stronger dispersing capacity; the kinetic instability index TSI value of the pigment yellow dispersion obtained in Example 1 was 4.24, while the kinetic instability index TSI value of the pigment yellow dispersion obtained in Comparative Example 1 was 86, indicating that the modified cellulase could significantly improve the stability of the pigment dispersion.

[0017] Example 2

[0018] (1) Cellulase and NaOH with a mass ratio of 5:1 were added into deionized water and dissolved thoroughly, and 60% of the mass of the cellulase was added with oleoyl chloride at 40°C, and the pH value of the system was maintained at 9-10 with a NaOH solution, and after the dropwise addition was completed, the temperature was increased to 50°C for 2 h of continuous reaction, then hydrochloric acid was added to adjust the pH value to 1-2, the precipitate was separated out and washed with deionized water until neutral, and vacuum drying was performed to obtain the modified cellulase;

[0019] (2) The organic pigment blue, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water and ultrasonically treated for 30 min to obtain a pigment dispersion.

[0020] Comparative Example 2

[0021] The organic pigment blue, cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 were added into deionized water and treated under the same conditions as in Example 2.

[0022] It was tested that the average particle size of the pigment blue dispersion obtained in Example 2 was 166 nm, while the average particle size of the pigment blue dispersion obtained in Comparative Example 2 was 1071 nm, indicating that the modified cellulase had stronger dispersing capacity; the kinetic instability index TSI value of the pigment dispersion obtained in Example 2 was 6.94, while the kinetic instability index TSI value of the pigment dispersion obtained in Comparative Example 2 was 38.93, indicating that the modified cellulase could significantly improve the stability of the pigment dispersion.

Claims

1. A method for improving the dispersing ability of a cellulase on an organic pigment, characterized by The following process is used: (1) Cellulase and NaOH with a mass ratio of 5:1 are added into deionized water to be dissolved thoroughly, and oleoyl chloride with a mass of 60% of the cellulase is slowly added at 40°C, and the pH value of the system is maintained at 9-10 by using NaOH solution, after the dropwise addition is completed, the temperature is increased to 50°C to continue the reaction for 2 hours, then hydrochloric acid is added to adjust the pH value to 1-2, the reaction product is precipitated and washed with deionized water to be neutral, and vacuum drying is performed to obtain modified cellulase; (2) Organic pigment, modified cellulase and sodium hydroxide with a mass ratio of 10:1:0.2 are added into deionized water, and ultrasonic treatment is performed for 30 minutes to obtain a pigment dispersion.