SU70744A1 - Method of bleaching sulphite and sulphate pulp - Google Patents

Description

From a number of base papers for further surface coatings and processing, high absorbency is required at a certain mechanical strength. For filtering and custom paper, etc., a composition is made of one cotton thread or with a predominant content of this thread in the composition. However, cotton trout cannot provide sufficient mechanical strength of the resulting paper base and high absorbency of these papers.

For the basis of the fiber and parchment, there were attempts to use special refined wood pulp, but the latter did not provide a sufficiently high absorbency of the resulting base papers, which also had little mechanical strength.

The proposed method of processing both sulphite and sulphate wood pulp using bleach solution allows obtaining a base paper with high absorbency and greater mechanical strength and consists in the fact that whitewashed pulp is first treated with a solution of ammonia or ammonia salts, after which a solution of bleach, the pH of which is brought to 11.5-12 by the addition of caustic soda or other alkali, and the treatment of cellulose continues for 1-3 hours.

The pulp obtained by the proposed method has a high absorbency and at the same time a sufficiently high mechanical strength and can be used in the manufacture of raw paper and filter paper, fiber, parchment, leather substitutes, etc.

Subject invention

A method of bleaching sulphite or sulphate pulp by treatment with bleach solutions, characterized in that the previously crushed pulp is first treated with a solution of 255

No. 70744 -2 -

rum ammonia or ammonium salts, 11.5-12 by adding caustic soda

After which a solution of chlorine or other alkali is introduced, and is treated

: Lead, the pH of which has been adjusted for 1-3 hours.