Production method for preparing bamboo dissolving pulp by utilizing natural-color unbleached bamboo pulp in a modifying way

Abstract

The invention discloses a production method for preparing bamboo dissolving pulp by utilizing natural-color unbleached bamboo pulp in a modifying way, overcoming the defect of poor reaction property of products prepared by an alkali refining method. The production method comprises the following steps of: concentrating and dewatering dredged natural-color unbleached bamboo pulp, and delivering to a double-helix roller type pulp grinder; continuously dewatering in the pulp grinder, and adding liquid medicine; continuously concentrating and kneading the pulp and mixing the pulp with the liquid medicine in the pulp grinder; then delivering the pulp to a stewing machine; and after stewing is completed, conducting subsequent procedures including washing and bleaching till paper making. The invention reduces the preparation cost, enhances the quality of products and increases resource supplying sources; in addition, the bamboo pulp prepared by the production method not only has higher content of alpha-celluloses, but also has good reaction property, and is suitable for filament and staple fibers.

Description

technical field [0001] The present invention relates to the production process and method of bamboo dissolving pulp (bamboo pulp) used for producing viscose fiber, especially the method for preparing dissolving pulp by modifying unbleached natural bamboo pulp, and is also suitable for preparing cellulose derivative products Chemical dissolving pulp and refined pulp. Background technique [0002] Pulp for viscose fiber requires high α-fiber content, that is, high fiber purity. Now the preparation of bamboo dissolving pulp (bamboo pulp) adopts pre-hydrolysis + alkali method (sulfate method) two-stage cooking or sulfite method. Two-stage (multi-stage) cooking adopts the above two cooking pulping techniques, mainly to remove a large amount of lignin, hemicellulose (pentose) and resin and other impurities in the raw material. Especially the hemicellulose (pentose) in the raw material is removed. Under acidic conditions, the hemicellulose (pentose) undergoes acidic hydrolysis, so...

AI Technical Summary

Problems solved by technology

[0004] Utilize the modification of paper-making grade bamboo pulp to prepare bamboo pulp now, all adopt bleached bamboo pulp (paper grade) to utilize higher concentration sodium hydroxide (NaOH) to impregnate bleached bamboo pulp, high concentration sodium hydroxide (NaOH) At a lower temperature (generally normal temperature), dissolve the semi-fibers in the bleached bamboo pulp (paper grade), and then squeeze out the excess lye (NaOH) and then properly reduce the viscosity of the purified pulp (reduce Viscosity or degree of polymerization), after washing and removing impurities, it is copied into pulp, and bleached bamboo pulp (papermaking grade) is used to modify bamboo (children) dissolving pulp (pulp), and its α-cellulose is relatively high (up to 98 %), and other indicators can basically reach the standard for viscose fiber. It is another method to prepare bamboo pulp (bamboo dissolving pulp) by pre-hydrolysis + alkali method (sulfate method) and sulfite multi-stage cooking. It is the alkali refining method. Due to the high alkali consumption and high concentration alkali (NaOH), it is difficult to recover the alkali solution, the slurry is not easy to wash, and the cost is high. Although this method can produce high-purity α-fiber pulp pulp, but as an important requirement for pulp in the production of viscose fiber, the reaction performance is poor, resulting in poor filterability in the production of viscose fiber, easy to block the spinneret, increased consumption during alkali prepreg, and at the same time CS 2 Also will corresponding increase, so the bamboo dissolving pulp (pulp) that this method produces can't satisfy the requirement of viscose fiber industry, can't compete with the bamboo pulp product that adopts other method preparation, and present this method basically does not adopt

[0005] According to the above description, whether the prior art is pre-hydrolysis + alkali method (sulfate method), sulfite method or alkali refining method, either there is a large investment, a long production cycle, or there are product quality defects