SU1708641A1 - Method for crepe paper manufacturing - Google Patents

Abstract

The invention relates to the pulp and paper industry, in particular to the production of creped types of paper, and allows you to increase the dynamic strength of paper, improve its consumer properties and expand the scope of its application. The method consists in grinding the sulphate unbleached pulp to 32-37 ° ShR, then the paper web is cast at a concentration of 0.30-0.40%, pressed, creped on a creping cylinder with a dryness of 40-43% and dried . Next, creped paper is treated with steam to a moisture content of 10-12% and is subjected to secondary creping at a pressure of installation shafts 1.5-2.0 kgf / cm ^, which makes the paper uniform and fine crepe, increased dynamic strength and fracture strength, followed by calendering at a pressure of 15-20 kgf / cm. The crepe paper obtained according to the proposed method can replace cotton fabric in various industries in printing, rubber, electrical, furniture, etc. 4 table.fe

Description

The invention relates to the pulp and paper industry, in particular to the production of creped paper of various technical purposes, for example, for binding materials, for the furniture industry, as a basis for rubberized materials instead of cotton fabric, in the electrical industry instead of keeper and taffeta tapes.

There is a known method of making paper base for windmills. It consists in that the sulphate unbleached pulp of a liquid stream is subjected to grinding to 18-22 ° SR and an average fiber length of 1.8-2.0 mm.

The paper is poured at a concentration of the fiber suspension in the pressure box of 0.35-0.45%. Formed on

the net table the paper web undergoes dewatering on presses to a dryness of 30-32%, then it is dried on drying cylinders with a surface heating temperature of 60 ° C in the first to 80-00 ° C in the last cylinders. The dried paper web with a moisture content of 5-8% passes through the machine.

This paper has insufficient fracture strength, low extensibility, as a result of which binding material is short-lived, has low performance and consumer properties.

A known method for the production of paper for the furniture industry. This paper is used for synthetic veneer. Due to its elongation, dynamic strength, fracture strength, it has limited application.

A known method for the production of rubberized bag paper, according to which rubberized paper is a basis paper bag weighing 80 g / m, coated on both sides with a rubber-bitumen mixture.

Due to the low elongation, rubberized paper has a low dynamic strength, which increases its breakage during processing and use.

Known micro-creped paper for pasting the roots of book blocks, which is obtained by passing it with a dryness of 6Q-70% through a two-shaft micro-creping device. To increase the strength, melamine-formaldehyde resin is introduced into the fibrous mass in the amount of 2.2-2.5% by weight of abs. dry fiber.

This paper has low elongation and dynamic strength, lower fracture strength as compared to macro crepe paper.

 Known macrocreped paper for medical dressing products, obtained by creping the web on the drying cylinder of the papermaking machine with a dryness of 75-85%.

The disadvantages of paper include the formation of coarse crepe due to the high dryness during creping, as well as the high consumption of expensive and scarce chemicals in the production of this paper.

Closest to the invention is a method of making creped paper using a crepe crepe method with a dryness of 38–40% on the first drying cylinder of a papermaker.

However, the dynamic strength of this paper is also insufficient.

The aim of the invention is the improvement of consumer properties, in particular the dynamic strength of paper, and the expansion of the field of application of crepe paper base.

The goal is achieved by the fact that after grinding, pouring, pressing, creping and drying, the paper is treated with steam to a moisture content of 10-12% and subjected to secondary creping at a roller pressing pressure of 1.5-2.0 kgf / cm followed by calendering at a pressure of 1520 kgf /cm.

Repeated creping allows you to get crepe paper with even crepe crease, and

also with a smaller crepe, and thereby achieve a well-developed surface that provides high adhesive strength of coated paper in combination with its high dynamic strength. This allows the use of a creped boog mage instead of a cotton base for various purposes.

The proposed method obtained samples of crepe paper.

When carrying out primary creping, known creping parameters were used, such as, for example, in preparing a base for two-ply crepe paper. The raw material used was unbleached sulphate pulp, which was milled to 3237 ° SR, cast at a concentration of 0.30-0.40%. After the paper web has been cast, it is creped by pressing the crepe with sheber mounted on a creping cylinder, with a dryness of 40-43%. The angle of the scraper to the tangent of the creping cylinder is 30-35 °. The surface temperature of the crushing cylinder was 7075 ° C, then the paper web was dried.

After drying, the paper was again moistened with steam to a moisture content of 10-12% and re-creped, maintaining the pressing pressure of the rolls of the installation 1.5-2.0 kgf / cm.

Secondary creping was carried out by passing paper through a device consisting of two rubberized metal shafts with a hardness of 60–70 Shore rubber, 5–15 mm thick rubber facing. With the passage of wet paper through the device, it is compressed with the formation of micro-folds on the paper. By fixing the crepe crease tops on the rubberized surface of the shafts and high friction between the rubber facing and crepe paper, the crepe crease folds are removed, and in the gap between the shafts, due to a certain amount of pressure, the crepe edges begin to deform without significant paper stretching accompanied by an increase in the number of crepe folds per unit length, a change in their geometric dimensions (see Table 1).

The obtained samples were tested for physico-mechanical properties, crepe parameters were determined. The test results are presented in Table. .

Claims (1)

Analysis of the results shows that secondary creping leads to the formation of small crepe folds. For example, the number of crepe folds is increased from 8 to 16, the crepe step is reduced 2.5 times, and the height of the crepe is 2 times. In tab. Figure 2 shows the physico-mechanical properties of creped paper after re-creping1, depending on the pressure of the mounting shafts, a linear installation speed of 40 m / min. From tab. 2 It follows that the process of re-creping of paper must be carried out at a pressure of pressing the shafts of the installation 1.5-2.0 kgf / cm. With a pressure of less than 1.5 kgc / cm, the paper has lower rates of breaking force and fracture. Increasing the pressure above 2.0 kgf / cm is impractical because it does not lead to an improvement in dynamic strength. As a result of re-creping, the paper structure is changed, it acquires a fine and uniform crepe, a well-developed surface and high adhesiveness to coatings while maintaining dynamic strength (breaking work). The newly acquired characteristics of the paper after re-creping improve its consumer and operational properties, which allows to expand the scope of application. After re-creping, paper calendering was performed at a pressure of 15-20 kgf / cm and a linear calendering speed of 40 m / min. This pressure range, as shown in table. 3, allows to obtain paper with the highest index of dynamic strength in the machine and transverse directions, which is the main consumer property of crepe paper. By reducing the pressure during calendering to 10 kgf / cm, the breaking force and the dynamic strength of the paper decrease, while increasing the pressure to 25 kgf / cm: the relative elongation during stretching and the fracture index c decrease. machine direction due to some crushing of the web and violation of its structure. From tab. 4 it follows that the paper obtained by the proposed method has a higher dynamic strength and fracture strength as compared to micro-creped paper and serial one. This provides the paper with increased safety under dynamic loads, continuous processing during processing, and improved performance and consumer properties. The increased extensibility, high dynamic strength and well-developed surface of the paper, acquired by it in the process of secondary crepeing, in combination with the smoothness and elasticity after calendering, make it possible to use crepe paper produced by the proposed method in the furniture industry instead of synthetic filament. in the production of bookbinding; and the rubberized materials instead of a fabric basis, in the electrotechnical industry. The formula of the invention and the Method of making a cut paper by grinding, casting and pressing with subsequent scraper creping and drying of the web, which is different from the fact that, in order to increase the dynamic strength of the paper, improve consumer properties and expand its application area after drying, the paper web is treated with steam to a moisture content of 10-12% and subjected to secondary creping with shafts at a pressure of 1.5-2.0 kgf / cm followed by calendering on horizontal calenders at a pressure of 15-20 kgf / cm. Table 1 Table 2 Table3 vO ir oo CTv about oh oh il r -aCD 4 -35 o Tg - about 1L ff about silt cho oh oh year r. oh oh SE r- " SP CM about CM ft vO GLo o o oo Ln mid stch SE s vO with CM JCM oh oh about -aCM SE CM go j