CN115772823A - Method for improving color fastness of kraft paper - Google Patents

Abstract

The invention discloses a method for improving the color fastness of a kraft paper. The dyes used by the craft paper are anionic yellow dyes and cationic red dyes, and the adding sequence of the dyes is as follows: firstly, adding a cationic red dye to attach positive charges to the negatively charged craft paper fibers and the filler; secondly, adding an anionic yellow dye, and enabling the anionic yellow dye to be attached to the cationic dye with positive electricity; the dye addition amount is as follows: amount of anionic yellow dye used: 1KG per ton of paper, 0.15KG of cationic red dye per ton of paper, and the addition error of the two dyes is within 10 percent. By adopting the scheme, the anionic yellow dye has the characteristics of high strength, high color fastness, reddish color and the like. By adjusting the adding sequence of the dye, firstly adding the cationic red dye and then adding the anionic yellow dye, the coloring point and the coloring area of the dye are increased, and the aims of reducing the dyeing cost and improving the color fastness of the original value are achieved together.

Description

Method for improving color fastness of kraft paper

The technical field is as follows:

the invention relates to the technical field of craft paper dyeing, in particular to a method for improving the color fastness of craft paper.

Background art:

craft paper, also known as kraft paper, is the main paper species for making cartons. Along with the popularization of online shopping, the consumption of the craft paper is greatly increased, and the quality requirement of the craft paper is gradually improved. At present, an important link in the process of manufacturing the craft paper is dyeing. The dyes used in current paper dyeing are classified into anionic dyes and cationic dyes according to the ionic charge in the aqueous solution, and most kraft paper is dyed with cationic dyes. The dyeing principle of the cationic dye is as follows: the cationic dye is attached to the fibers through attraction of anions and cations with the paper fibers and hydrogen bonds. However, cationic dyes have lower strength than anionic dyes and require higher amounts of dye to achieve the same hue. However, if the anionic dye is directly used, the anionic dye is hydrogen-bonded to the fibers of the paper, and the bonding points with the fibers are relatively small.

In order to overcome the above problems, the present inventors have made extensive tests and propose the following technical solutions.

The invention content is as follows:

the invention aims to provide a method for improving the color fastness of kraft paper.

In order to solve the technical problems, the invention adopts the following technical scheme: the dyes used by the craft paper are anionic yellow dyes and cationic red dyes, and the adding sequence of the dyes is as follows: firstly, adding a cationic red dye to attach positive charges to the negatively charged craft paper fibers and the filler; secondly, adding an anionic yellow dye, and enabling the anionic yellow dye to be attached to the cationic dye with positive electricity; the dye addition amount is as follows: anionic yellow dye dosage: 1KG per ton of paper, 0.15KG of cationic red dye per ton of paper, and the addition error of the two dyes is within 10 percent.

After the scheme is adopted, compared with the method of directly using the cationic dye, the anionic yellow dye has the characteristics of high strength, high color fastness, reddish color and the like. By adjusting the adding sequence of the dye, firstly adding the cationic red dye and then adding the anionic yellow dye, the coloring point and the coloring area of the dye are increased, and the aims of reducing the dyeing cost and improving the color fastness of the original value are achieved together.

Description of the drawings:

FIG. 1 is a schematic representation of the dyeing of the present invention.

The specific implementation mode is as follows:

the invention is further illustrated below with reference to specific embodiments and the accompanying drawings.

The invention relates to a method for improving the color fastness of kraft paper, wherein dyes used by the kraft paper are an anionic yellow dye and a cationic red dye, and the adding sequence of the dyes is as follows:

firstly, adding a cationic red dye to attach positive charges to the negatively charged craft paper fibers and the filler;

secondly, adding an anionic yellow dye, and enabling the anionic yellow dye to be attached to the cationic dye with positive electricity;

the dye addition amount is as follows: anionic yellow dye dosage: 1KG per ton of paper, 0.15KG of cationic red dye per ton of paper, and the addition error of the two dyes is within 10 percent.

As shown in the combined figure 1, the dyeing principle of the invention is as follows: the cationic red dye is added firstly, so that the positive charges are rapidly attached to the paper fibers and the filler with negative charges and can be combined with hydrogen bonds on the fibers at the same time. Then adding anionic yellow dye, the yellow dye can be combined with dye with positive electricity and hydrogen bond, thereby achieving the purpose of increasing the coloring point and coloring area of the dye.

By contrast, the anionic yellow dye has the characteristics of high strength, high color fastness, reddish color and the like. Compared with the existing cationic dye dyeing method, the method has the advantages that the flow of the yellow dye is reduced by 30L/h, the flow of the red dye is reduced by 4L/h, the cost of the paper dye is saved, the color fastness of the produced kraft paper is improved, the condition of color change is avoided, and the color difference is avoided.

It should be understood that the above description is only exemplary of the present invention, and is not intended to limit the scope of the present invention, which is defined by the appended claims.

Claims (1)

1. The method for improving the color fastness of the kraft paper comprises the following steps of:

firstly, adding a cationic red dye to make positive charges attach to kraft fibers and fillers with negative charges;

secondly, adding an anionic yellow dye, and enabling the anionic yellow dye to be attached to the cationic dye with positive electricity;

the dye addition amount is as follows: amount of anionic yellow dye used: 1KG per ton of paper, 0.15KG of cationic red dye per ton of paper, and the addition error of the two dyes is within 10 percent.

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