SU499356A1 - The method of obtaining viscose fibers - Google Patents

Description

The invention relates to the field of chemical fiber production, in particular to methods for producing viscose fiber by molding viscose into aqueous acid-salt precipitation baths. The known method of forming viscose yarns with the elementary fiber number not more than 9000. The method consists in the fact that an out-goose containing 6% caustic soda and 7% a-cellulose, including with respect to the percentages of these components - 0.86, is passed through a spinneret into a sedimentary acid-salt bath, selected experimentally to form a certain assortment of thread 1. There is also known a method of forming viscose fibers of a higher metric number by forming viscose with a percentage ratio the content of caustic soda and a-cellulose 0.85-0.95 in concentrated sulfuric acid 1. This method allows yarn with a metric number of elemental fibers of 15000-30000, however, due to the use of concentrated sulfuric acid, the method is associated with a number of technical and technological difficulties and therefore unacceptable under production conditions. Known is a method for obtaining viscose fibers with a number of elementary fibers above 90000 by molding young viscose with preliminary coagulation in funnels containing H2S04 with a concentration of 0.8-1.0%, and fixing the fiber obtained in the second bath 2. The existence of two baths according to a known method makes this method is also not practical because the design of the spinning machine becomes more complicated as its dimensions increase and its productivity decreases accordingly. Additional maintenance is also required, additional repair of the machine and additional equipment with materials to maintain such a bulky machine, i.e., in addition to additional capital investments when installing such a machine, additional funds are required for its operation. However, the main disadvantage of the method is the instability of the technology. Very precise adherence to technology is required, in particular, viscosity viscosity and coagulation bath parameters in order to draw viscose jet in the coagulation zone with a length of 1.5-2 mm. In order to simplify the technology and obtain high-number viscose fibers, a method has been proposed.

that viscose is sent to molding with a ratio of caustic soda to cellulose of 1.2-25 and the precipitation bath contains 9-50 weight. % strongly dissociated acid, 1 - 20 wt. % of its salts and water.

The method of producing ultra-high metric number viscose fibers can be implemented on any of the existing types of viscose manufacturing equipment, including intermittent and continuous production of viscose fibers.

Increasing the content of caustic soda in viscose is accomplished by adding caustic soda in crystalline form or as a solution in the mercerizing of cellulose, grinding alkaline cellulose or dissolving cellulose xanthate or in certain quantities at all stages of viscose production.

The composition of the precipitation baths can include strongly dissociating acids and salts of mineral origin.

Forming is characterized by a significant decrease in the amount of viscose during spinning per unit of time, and an increase in the rate of reception of the finished fiber on the spinning disc.

The use of a new technology of forming viscose fibers significantly accelerates the processes associated with the dehydration of the "liquid filament", as a result of which the molding processes as a whole proceed more intensively.

The shaping of ultrafine viscose fibers in combination with plasticization stretching makes it possible to significantly improve the physico-mechanical properties of the viscose yarn. The production and use of ultrafine viscose fibers will not only significantly expand the range of viscose yarn, staples and cord, but may also lead to new positive effects in the production of paper and cardboard, adhesive and nonwoven materials, and the production of fiber and artificial fur.

Example 1. Viscose containing 6% a-cellulose and 16% caustic soda (ratio 2.7), with a degree of xanthogenation 45, is passed through a spinneret 1000 / 0.07 when a gear pump of 7.2 ml / min is fed into a precipitation bath having following parameters:

Sulphate content

zinc, g / l 60

Sulphate content

sodium, g / l 10-12

Sulfuric acid content, g / l93 Equivalent conductivity of the precipitation bath, Ohm - cm-G-eq 70 Forming temperature, ° С 70

The formed fiber is fed onto a biscuit with a rotation speed of 20 m / min. Metric thread number 40, elementary fiber number 40000.

Example 2. Viscose prepared from Korditsel-super-20 cellulose without pre-maturation, containing 4% a-cellulose with SP-60 and 20% caustic soda (ratio 5.0), with a degree of xanthogenation 90 is passed through a die plate 1500/0 , 05 when applying viscose 6 ml / min to a precipitation bath with the following parameters:

Content of sulfuric acid, g / l 500 Content of sodium sulfate, g / l 10 Content of zinc sulfate, g / l 150 The dielectric constant of the solution without

acids48

Molding temperature, ° C. 15 The fiber is fed to a rotating wafer at a speed of 20 m / min. Metric yarn number 70, elementary fiber number 105000.

Example 3. Viscose, obtained without pre-maturation from larch pulp with a degree of polymerization of 1500, containing 2% a-cellulose, 30% caustic soda (ratio 15), with a degree of xenogenesis 90 is passed through a die plate 1500 / 0.05 with a 6-ml gear pump / min in a precipitation bath, having the following parameters:

Sulfuric acid content, g / l260 Acetic acid content, g / l 200 Sulfate content

sodium, g / l10

The dielectric constant of the solution without sulfuric acid40,72

Molding temperature, ° C15. The molded yarn is taken on a biscuit at a speed of 20 m / min. Metric yarn number 92, elementary fiber number 138000.

Claims (2)

Invention Formula The method of obtaining fine viscose fibers by molding viscose into an aqueous acid-salt precipitation bath is also distinguished by the fact that, in order to simplify the technology and obtain high metric fiber fibers, viscose with the ratio of caustic soda to cellulose 1.2-25 is molded into a precipitation bath containing 9-50 weight. % strongly dissociated acid and I - 20 wt. % of its salts. Sources of information taken into account and expertise. 5 1. Rogovin 3. A. Fundamentals of chemistry and technology of chemical fibers. “Chemistry, 1964. b 2. Patent of France No. 890575 gr. 4 cl. 1, 1944.