SU1759972A1 - Method of producing cardboard - Google Patents

Abstract

SUMMARY OF THE INVENTION: In the manufacture of paperboard, to increase its strength and productivity, a 2-10% solution of aluminum oxychloride is used, which is introduced into the machine pool of the cardboard machine at a speed of 60-100 l / h. The consumption of aluminum oxychloride is 0.1-0.4% by weight of absolutely dry fiber. 1 hp f-ly, 1 tab.

Description

The invention relates to the paper industry, in particular to the manufacture of cardboard.

A known method for producing cardboard is by grinding the raw material, introducing aluminum oxychloride into it and forming a web on a cardboard-making machine.

The disadvantage of this method is the slight introduction of aluminum oxychloride into the cardboard mass (0.0005-0.05% of absolutely dry fiber). This amount of aluminum oxychloride does not affect the physicomechanical properties of the resulting cardboard.

The known method of introduction into the paper pulp containing the filler is aluminum oxychloride in the amount of 0.5-3% (in terms of) of the weight of absolutely dry fiber. Aluminum oxychloride is introduced in the form of a 1% solution in order to retain the filler.

The disadvantage of this method is the large introduction of aluminum oxychloride and the use of a 1% solution. The specified amount of aluminum oxychloride is necessary to retain the filler, which has a small fractional composition. When the fiber itself is retained, the indicated amount of aluminum oxychloride retains a large amount of small particles (milshtof), which significantly impairs the physicomechanical properties of the resulting cardboard. The use of a 1% solution of aluminum oxychloride entails a high consumption of water in the technological cycle, which is unprofitable. To obtain cardboard with a given moisture content, it is necessary to increase the drying time, which reduces the productivity of production.

The closest in technical essence and the achieved result to the proposed is the method of producing cardboard by grinding the raw material in hydro

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sbivatel, introducing into the mass of aluminum oxychloride and the formation of a sheet on a carpentry machine.

The quality of the cardboard produced by this method is characterized by the following indicators:

the rest of the carton mass in water (medium) is 0.7 g / l,

weight of 1 m cardboard 440 g

hardness, 140 g / cm,

fracture force, the number of double kinks 20.

This invention will improve the known method and is aimed at improving the physico-mechanical properties of the resulting paperboard and increasing the retention of the cardboard mass.

The injection site of the aluminum oxychloride solution also has a significant effect on the increase in the percentage of poor-quality paperboard, which is confirmed by the attached table.

The aim of the invention is to manufacture cardboard with improved physicomechanical indicators and increase productivity due to better fiber retention.

To do this, in the method of making cardboard, which includes grinding the fibrous semi-finished product in hydrobibblers of the cardboard mass, introducing aluminum oxychloride, casting the fabric on a cardboard-making machine and drying, aluminum oxychloride is used as a 2-10% solution and injected into machine pool of the cardboard machine with a speed of 60-100 l / h. Aluminum oxychloride should be used in an amount of 0.1- 0.4% by weight of absolutely dry fiber.

The method provides improvement of the physicomechanical properties of cardboard, expressed in an increase in stiffness and breaking force by an average of 20% due to the introduction of aluminum in the mass of the oxychloride with the specified concentration, with the feed rate within the limits and also due to the insertion point; by keeping a large amount of the cardboard mass by 30-35%, and also due to the feed rate of the aluminum oxychloride solution within the limits.

The retention of a large amount of cardboard stock ensures the efficient operation of the wastewater treatment plant and allows water to be repeatedly used in the technological cycle.

Cardboard production according to the described method is performed as follows.

The cardboard pulp is crushed in water beaters. Then, the crushed mass is passed through thickeners and fed into the machine pools of the paper-making machine (CMM), from which the cardboard mass is fed to the CMM for

making cardboard.

Before serving, the 2–10% AI2U3 alumina oxychloride solution at a rate of 60–100 l / h is introduced into the cardboard mass in the machine pools at CDM.

0 Cardboard pulp with aluminum oxychloride is fed to CYM, where the stage of web formation, preliminary and final drying takes place.

Example 1 (the best option).

5 Cardboard paste was fed to a hydroscillator, where it was converted to a homogeneous mass. The resulting mass passed thickeners and fed into the machine basins of the CY. Before serving on CMM in the cardboard mass,

0, which is located in the KDM engine pools, was injected with a 7% AC & oz alumina oxychloride solution at a rate of 80 l / h. Then, the cardboard mass with aluminum oxychloride was supplied to the CYM, where it passed the stage of web formation, preliminary and final drying.

At the stage of web formation, the water that goes to the treatment plant is separated. In this case, the number

0 fibers in water is 0.5 g / l.

Other examples of the use of aluminum oxychloride in the production of cardboard are presented in the table.

As can be seen from the table, when an aluminum oxychloride solution is supplied with a concentration or feed rate less than the specified limits, an improvement in the physicomechanical properties almost insignificant almost at the level of the prototype occurs.

0 of the resulting cardboard, as well as the retention of the cardboard mass on the CMD out of water (example 6 and 8). When feeding an aluminum oxychloride solution with a concentration or with a feed rate greater than the specified limits, it proceeds, apparently due to the retention of a large number of small particles (milshtof) and deterioration of the physicomechanical properties of the resulting paperboard (example 7 and 9), despite the fact that the residual cardboard content Noah mass in water decreased. With the introduction of oxychloride in a cardboard mass, the adhesion of particles occurs, which leads to poor web formation, to frequent breaks (example 10).

five

With the introduction of aluminum oxychloride directly onto the CMM fabric due to the short residence time, the oxychloride does not affect the physicomechanical properties of the resulting cardboard.

Claims (2)

Claim 1. Method of making cardboard, which includes grinding the fibrous semi-finished product in hydrobibblers of cardboard mass, the introduction of aluminum oxychloride, casting the fabric on a cardboard machine and drying, characterized in that in order to improve the physical and mechanical properties of cardboard and increase productivity by better retention the fibers, aluminum oxychloride are used in the form of a 2-10% solution and are introduced into the machine pool of a cardboard machine at a speed of 60-100 l / h. 2. A method according to claim 1, characterized in that aluminum oxychloride is used in an amount of 0.1-0.4% by weight of absolutely dry fiber.