RU2237768C1 - Method for producing of cellulose-containing materials - Google Patents

Abstract

FIELD: pulp-and-paper industry, in particular, manufacture of paper and cardboard.

SUBSTANCE: method involves preparing composition of fibrous pulp with the use of chemical additives; forming and molding web; drying web. Chemical additives are lignosulfonates. After introducing into fibrous pulp of lignosulfonates, settler, such as aluminum polyoxychloride, is additionally introduced.

EFFECT: increased efficiency and improved quality of products of pulp-and-paper industry.

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Description

The invention relates to the pulp and paper industry and can be used in the manufacture of paper and cardboard.

Closest to the claimed is a method of manufacturing cellulose-containing materials, including the composition of the pulp using chemical additives, forming the web, pressing and drying, and lignosulfonates are used as a chemical additive (see RF patent No. 20169615, class D 21 H 11 / 106 1994).

A disadvantage of the known solution is the insufficient quality indicators of products from cellulose-containing materials.

The problem solved by this invention is as follows: the emergence of the possibility of efficient use of lignosulfonates in the pulp and paper industry, an increase in the strength of the pulp-containing material, as well as an increase in its hydrophobicity; increased retention of fine fiber and filler in the cellulose-containing material web during its molding and, therefore, better material quality and more efficient operation of the equipment.

The solution to this problem is provided by the fact that in the method of manufacturing a cellulose-containing material, including composing a pulp composition using chemical additives, forming the web, pressing and drying it, lignosulfonates are used as a chemical additive, and after feeding lignosulfonates into the pulp, an additional precipitant is introduced into the quality of which is used aluminum polyoxychloride.

The technical essence of the invention is as follows.

Lignosulfonates are crosslinked, high molecular weight compounds that dissolve well in water and dissociate to form anionic macromolecules. After they are fed into the pulp and sufficiently mixed, aluminum polyoxychloride, which dissociates in water and has the properties of a cationic polyelectrolyte, is also fed thereto. Lignosulfonates enter into an exchange reaction with aluminum polyoxychloride, which results in the formation of an aluminum-containing high molecular weight compound (aluminum polyoxyl lignosulfonate), whose macromolecules have a pronounced positive charge and are able to efficiently precipitate and adhere to a negatively charged cellulose fiber. When forming a cellulosic material, aluminum polyoxylignosulfonate contributes to better bonding between the cellulosic fibers, the retention of fine fiber and filler in the cellulose-containing fabric, and the increase in the strength and hydrophobic characteristics of the material. The formation of aluminum polyoxylignosulfonate can be represented by the scheme

The invention is illustrated by the following example.

Offset paper No. 1 was made with an ash content of 22% with the following fiber composition: bleached softwood sulphate pulp 50%, grinding degree 30 ° SR; 50% bleached sulphate hardwood pulp, grinding degree 32 ° SR. Production of offset paper No. 1 on a laboratory sheet-sieving apparatus includes the following steps:

1. Dissolution of the fibrous material (cellulose) in water with the formation of a water-fiber suspension.

2. Introduction to a water-fiber suspension of a mineral filler (chalk).

3. Introduction to the aqueous-fiber suspension of chemical additives in the following sequence and with the following dry matter costs: lignosulfonates 10 kg / t; rosin glue 5 kg / t; aluminum polyoxychloride 20 kg / t (the proposed method); aluminum sulfate 20 kg / t (the closest analogue).

4. Adjusting the pH of the aqueous fiber suspension with the addition of sulfuric acid or sodium hydroxide to the desired value (7.0 - the proposed method; 5.0 - the closest analogue).

5. The formation of the paper web, which consists in filtering a water-fiber suspension through a grid of a sheet-forming apparatus with the formation of a wet paper web on a grid.

6. Pressing the paper web, consisting in the mechanical extraction of water from it using a special roller.

7. Drying the paper web at a temperature of about 95 ° C for 7 minutes.

In this way, offset paper No. 1 is obtained, a comparison of the quality indicators of which with the same type of paper obtained by the closest analogue is shown in the table. The consumption of lignosulfonates in the proposed method and its closest analogue is the same and is 10 kg / t.

The amount of lignosulfonates and precipitant is determined depending on the type of paper and cardboard, the quality of industrial water, and other technological factors and can be (in terms of dry matter):

- lignosulfonates - 2 ... 15 kg / t;

- aluminum polyoxychloride - 2 ... 40 kg / t.

From the above data it is seen that the paper obtained by the proposed method, in some qualitative indicators, in particular in strength and hydrophobic, surpasses the paper obtained using the closest analogue. In addition, an important point is the possibility of using chalk instead of a deficient kaolin, superior to kaolin in terms of whiteness, as a paper filler. In the case of using the closest analogue, the pH cannot be higher than 5.0, since under these conditions the necessary hydrophobic properties of the paper cannot be achieved. The transition to molding the material in a neutral medium (pH 7.0), proposed in the new method, will make it possible to obtain higher quality material and improve the manufacturing process.

Claims (1)

A method of manufacturing cellulose-containing materials, including composing the pulp composition using chemical additives, forming the web, pressing and drying it, and using lignosulfonates as a chemical additive, characterized in that after feeding the lignosulfonates into the pulp, a precipitant is additionally introduced, which is used as polyoxychloride aluminum.