SU914665A1 - Settling bath for forming copper-ammonia fibre - Google Patents

Description

The invention relates to the production of cellulose hydrate fibers by molding from copper-ammonium spinning solutions of cellulose.

The acid-salt precipitation bath is known for producing hydrate- ⁵ cellulose fiber by molding a copper-ammonium spinning dope [1].

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However, acid-salt baths are characterized by a disadvantage due to the neutralization of all the ammonia and copper hydroxide contained in the spinning solution, and the associated high consumption of sulfuric acid.

In addition, as a result of ammonia binding, sulfuric acid is formed. large amount of by-product (in the form of ammonium sulfate) which hinders _m sculpt subsequent regeneration process ♦ spin bath components as a result of the need for the crystallization process and

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separation of a mixture of ammonium sulfate and sodium.

Closest to the invention is a salt precipitation bath containing ammonium sulfate, copper and sodium. The use of a precipitation bath of such a composition for forming cellulose hydrate from copper – ammonium spinning solutions, as compared with acid-salt precipitation baths, makes it possible to reduce the specific consumption of sulfuric acid and ammonia per ton and 0.2 ton per ton of fiber, respectively, while maintaining the physical mechanical performance of the finished fiber (2).

However, the known method does not eliminate the need to carry out the stage of crystallization and separation of the components of the precipitation bath in the process of its regeneration.

The aim of the invention is to reduce the consumption of reagents.

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components

. This goal is achieved by the fact that a precipitation bath containing copper salt, ammonium and sodium sulfates and water additionally contains ammonia, and, as a copper salt, 5 is cuprite tetra aminosulfate in the following ratio

weight.%:

Ammonium sulfate Cuprietraamine sulfate

Sodium Sulphate Ammonia Water

With such a ratio of components in the precipitation bath, the ammonium cellulose complex (MAAC) decomposes at a rate that ensures a stable process of fiber formation.

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10-20 0.5-5.0. . Rest.

When forming ammonium-copper fiber into the proposed precipitation bath, the properties of the fibers obtained are determined by the concentration of the components of the precipitation bath.

In general, a precipitating ’bath contains,%:

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Ammonium Sulphate Sodium Sulphate Cuprite tetraaminosulfate Ammonia Water

5-U

10-20

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0.5-5

Rest,

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The best physicomechanical indicators of the fiber are obtained by using precipitation baths of the following composition,%: (ΝΙ1 ₄ ) ^ 504 7 ~ 3; C (LC) ₄ 50 ₄ 5-7 ·, Ma _d 50 ₄ 15-18;

ΝΗ4 1-2 ·, water - up to 100%.

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Fiber; leaving the precipitation bath, pulled in air by 50-60% and then in a plasticizing bath by 20-40% at 70-85 ° C. Plasticization bath is a dilute aqueous solution of H ~ 50 ₄ (concentration 1.5 ^- 5%) or less. water-salt solution containing 2-10% (ΝΗ ₄ ) ^ 50 ₄ . Upon leaving the plasticization bath, the fiber is subjected to finishing in the usual way (washing with water, processing with an avivazhnym solution and drying). The fiber obtained has the following physical and mechanical parameters, in a state of fitness: linear density

0.1b7 "0.330 tex, strength 1822 gf / tex, elongation 20-25%.

Example 1. For preparing copper-ammonium spinning solution, cord sulphate pulp is used (K content, α-cellulose 97%, degree of polymerization 820).

The solution is obtained using copper hydroxide and a 25% ammonia solution. Preparation of the solution is carried out according to the following scheme: loading of cellulose and reagents - 0.5 h, dissolution - 2.0 h, dilution 1.5 h. The resulting solution after three-step filtration through non-woven nylon material and deaeration and for 5 h at residual pressure 100 mm Hg has the following composition,%: cellulose 12.5, copper 4, ammonia 6.0. Solution viscosity 350 s. SP of cellulose in solution 315 Spinning solution is formed through a spinneret 12000 / 0.080 into a precipitation bath having the following composition,%: (ΝΗ ₄ ) _α 50 ₄ 7,2} Cu (LH ₃ ) ₄ 50 ₄ 10.0 · Ma ^ 50 ₄ 15 , 5 ΝΗ 2 1, 4 ', water - up to 100. Spun extraction is 70%, bath temperature is 30 ° С. After the precipitation bath, the fiber is drawn in air at 50% and in a plasticizing bath (1.5% aqueous solution Η $$ ₄ ) at 30% at 75® C. Next, the fiber is finished in the usual way and dried. Forming speed 35 m / min. The fiber obtained has a linear density of 0.167 tex, a strength of 19 gf / tex at an elongation of 24%,

Example 2. Copper-ammonium spinning solution is prepared under the conditions described in example 1.

The resulting solution is formed into a precipitation bath of the following composition, / (ΝΗ _{4) α} 50 ₄ 10.0 Cu (Mo _{s) 4} April ₂₀ 8.5;

Νθ (χ50 ₄ 20.0; ΝΗ ₃ 0, 5 ·, water - up to 100. Forming is carried out through a spinneret 20000 / 0.08 with a spin drawing 1.00%. The temperature of the precipitation bath is 20 ° C. The fiber after the precipitation bath is drawn in air and at 35% in a plasticizing bath, which is a 10% aqueous solution of ammonium sulfate at 80 ° C. Formation rate; 40 m / min After the plasticizing bath, the fiber is trimmed in the usual way and dried.

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The resulting fiber with a linear density of 0.25 tex has a strength of 20.5 gf / tex at an elongation of 23%.

Example 3 · A copper-ammonium spinning dope is prepared as described in Example 1.

The resulting solution is molded into a precipitation bath having the following composition,%: (,) _and 50 ₄ 7.5; 0υ ( ₃ ) ₄ $ 0 ₄ 8,1-, Иа ^ ЗО ₄ 18.0; HH ₃ 1.0; water up to 100. Forming the fiber through the die plate 10,000 / 0.07 is carried out with a die drawing hood of 110% and a bath temperature of 35 ° C. The fiber after the precipitation bath is drawn by 60% in air and by 40% in a plasticization bath containing 2.5% sulfuric acid. The temperature of the plasticization bath is 75 ° C, the molding speed is 40 m / min. The finishing and drying of the fiber is carried out in the usual way.

A fiber is obtained with the following characteristics: linear density 0.33 tex, strength 22 gf / tex, elongation 21%.

Example 4. Copper-ammonium spinning solution is prepared as described in Example 1.

The forming of the fiber is carried out through a die plate 10000 / 0.08 into a precipitation bath of the following composition,%: (MH ₄ ) _g 5O ₄ 5.0; C (PN ₃ ) ₄ 50 ₄ 3.0;

Yad $ 0 ₄ 10.0; 5 ₃ 5.0; water - up to 100. Spun extraction is 55%, bath temperature is 24 C. After the precipitation bath, the fiber is drawn in air by 50% and in a plasticizing bath (5% aqueous solution of H ^ 50 ₄ ) by 20% at 85 ° C. Forming speed 45 m / min. After the plating bath, the fiber is trimmed in the usual way and dried.

The finished fiber has the following indicators: linear density 0, SJ tex, strength 18.5 gf / tex, an elongation of 25%.

The advantage of the proposed salt precipitation bath compared to the known is the possibility

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more complete return to technology

Editor L.Lukach

An ammonia cycle in the precipitation bath in unbound form or in mind of cupricetraamine sulfate, which saves about 0.4 tons of ammonia per 1 ton of fiber.

At the same time, the absence of formation of fiber by-products in the fiber molding process makes it possible to exclude the salt crystallization stage from the recovery bath regeneration scheme, which makes it possible to carry out the copper regeneration process in a closed loop and to save about 1.3 tons per 1 ton of fiber.

In addition, an increase in the content of alpha-cellulose in the newly formed fiber to 17–18.5% versus 13.5 ”14.5% with a salt version of the precipitation bath reduces the entrainment of the components of the precipitation bath with fiber and, consequently, reduces the specific consumption of sodium sulfate by 1.5 tons per 1 ton of fiber.

Claims (1)

Claim A precipitation bath for the formation of copper-ammonia fiber containing copper salt, ammonium and sodium sulphates and water, characterized in that, in order to reduce the consumption of reagents, the bath additionally contains ammonia, and as a copper salt, cupritetramine sulphate in the following ratio of components, weight. %: 40 45 Ammonium sulfate 'Cupritetraaminosulfate Sodium sulfate Ammonia Water 5-U 3-10 10-20 0.5-5.0 Else