Preparation method of cotton pulp for high-strength paper

Abstract

The invention relates to a preparation method of cotton pulp for high-strength paper. In the preparation method, a material sorting process, a cotton opening process, an impurity removal process, an alkali preparation process, a dipping process, a steaming and bleaching process, a pre-desanding process, a pre-pulping process, a concentration process, a post-desanding process, a post-pulping process and a pulp copying process are performed on cotton linter to obtain the cotton pulp. The alkali preparation and dipping processes comprise the following steps of: controlling the alkali preparationtemperature to be between 30 and 40 DEG C; adding 2 to 3.5 percent of NaOH, 0.1 to 0.2 percent of anthraquinone, 2.5 to 3.5 percent of boiling agent and 2 to 3 percent of peracetic acid according to oven dry stock amount to obtain alkali liquor, wherein the alkali liquor proportion is 1:(4.5-5.5); and performing penetration mixing on the alkali liquor and the cotton linter from which impurities are removed. By the method, pulp fibers have high folding strength, high breaking length and high whiteness, pollution to the environment is reduced, and fluorescent substances are removed in the firstheat preservation process.

Description

technical field [0001] The invention relates to a method for preparing cotton pulp, in particular to a method for preparing cotton pulp for high-strength paper. Background technique [0002] my country is rich in cotton resources, and most domestic enterprises use cotton linters, a by-product of cotton processing, as raw materials. For example, in the textile field, cotton linters are used as raw materials to make cotton pulp for the production of viscose fibers. The added value is low, and in production, the COD discharge of wastewater is about 45000mg / l, which has the problem of polluting the environment. [0003] At present, the international market has a great demand for paper, especially high-strength paper such as banknotes, aviation, navigation, and drawings. With the rapid development of the paper industry, higher requirements are put forward for high-strength paper. High-end paper products mostly use cotton pulp. The quality index of ordinary cotton pulp cannot meet...

AI Technical Summary

Problems solved by technology

[0002] my country is rich in cotton resources, and most domestic enterprises use cotton linters, a by-product of cotton processing, as raw materials. For example, in the textile field, cotton linters are used as raw materials to make cotton pulp for the production of viscose fibers. The added value is low, and in production, the COD discharge of wastewater is about 45000mg / l, which has the problem of polluting the environment

[0003] At present, the international market has a great demand for paper, especially high-strength paper such as banknotes, aviation, navigation, and drawings. With the rapid development of the paper industry, higher requirements are put forward for high-strength paper. High-end paper products mostly use cotton pulp. The quality index of ordinary cotton pulp cannot meet the standard of cotton pulp for high-strength paper, which seriously affects the quality of high-strength paper. Among them, the most difficult problem of cotton pulp is that it is difficult to meet the requirements of fiber length and freeness at the same time. Moreover, the content of fluorescent substances is high and the strength is low, which is far from meeting the performance of high-grade paper.

[0004] Although very few enterprises have researched on the production of cotton pulp for high-grade paper, the alkaline hydrogen peroxide steaming and bleaching process has been used instead of the traditional pulping process. Due to the defects in the production process, the content of fluorescent substances is not controlled, and the content of fluorescent substances The content is relatively high, the length and freeness of the fiber are not well controlled, the strength is low, and the dust is high, which cannot meet the special requirements of the international market

[0005] The Chinese patent with the application number 01136234 discloses a method for producing cotton pulp using a horizontal tube continuous steaming and bleaching process. After the bleaching and bleaching process is completed, the cotton fiber in the slurry entering the horizontal tube steaming and bleaching equipment has been cut short. The steaming and bleaching process uses sodium hydroxide and hydrogen peroxide as the bleaching agent, and also adds wetting agent and The stabilizer does not control the fluorescent substance, fiber length and freeness. The fluorescent substance affects the anti-counterfeiting ability of the paper, and the fiber length and freeness affect the paper strength. The pulp quality index of the produced cotton pulp: the concentration is 3.0-4.5 %; percussion degree is 12-160°SR; wet weight is 14-18g; whiteness ≥ 80%; dust ≤ 100mm 2 / 500g absolute dry pulp; semi-pulp strength: breaking length ≥ 3500m; folding resistance ≥ 1500 double, cannot be used as raw materials for high-strength paper manufacturing in the paper industry