JPS5813712A - Continuous production of viscose rayon fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous method for manufacturing V-scose rayon yarn. More particularly, the invention relates to a simplified method for the continuous production of high whiteness viscose rayon yarn.

As is known in the art, continuous spinning of visco-threin involves the yarn being wound around rollers arranged at an angle to each other while traveling in a substantially helical path. , I wonder) is carried out through a series of complicated processes.

A plurality of threads are processed by a single spinning machine, and a process of this type is described, for example, in Italian Patent No. 1i128324A/78, filed by the applicant.

When using the obtained viscose rayon yarn in textiles, it is necessary that the yarn has a certain degree of whiteness.
This whiteness can be measured by standard tests described below.

To this end, after the yarn has been coagulated in a coagulation bath, it is typically subjected to curing, desulfurization, bleaching, finishing, and various cleanings, in addition to a final drying. Desulfurization and bleaching are essential to obtain sufficient whiteness.

In this field, improvements in the above-mentioned processes were sought, ie, on the one hand, a reduction in the processing time and, on the other hand, a reduction in the winding space of the spinning machine, or both. In the past,
It has been proposed to reduce the number of treatments by sacrificing some whiteness. However, the obtained yarn can only be used for limited purposes. This invention is
Simplifying the continuous manufacturing process of visco:1'-thrayon yarn without sacrificing whiteness: °;
,.

It solves the problem of reducing the time and/or the winding space of the spinning machine.It also solves the problem of reducing the size of the winding space of the spinning machine. All this is done in an extremely simple and economical manner.

The process of this invention is a partially solidified, fully stretched (typically a stretch ratio of 1 to 1.57), preferably already leaving the coagulation bath and ready for final processing into a substantially helical or other shape. It consists of subjecting the yarn, which has started moving along a path of the shape of , to the following processing.

That is, 1. At the outlet of the coagulation bath, complete coagulation of the thread whose coagulation index, or "gamma index" defined later, is 15 to 25 until the final coagulation index becomes 1 or less, and 2. Treat with non-basic water until the following elements possessed by the thread are reduced to the values shown below (this treatment can be called "washing") - Total sulfur: 0. 2% or less, next ion bound as sulfide: 0.02s or less, elemental sulfur: 0,06S or less, iron: 40 ppln or less, preferably 20 ppl
Zinc: 700 ppm or less, preferably 50 ppm or less
0 pPf11 or less, lead: 30 ppm or less, preferably 10 ppm or less.

Completion of coagulation can be accomplished in a variety of ways, including:

a) Simply wait for time to pass without applying any reagents or liquids other than those attached to the thread.

b) Acid treatment. Acid treatment at 50°C to 100°C in a sulfuric acid bath which may contain, for example, zinc sulfate and/or sodium [acid].

C) Perform the above two processes a) and b) consecutively.

Other substitutions or additional treatments are also possible, such as treatment with multiple baths with different acidities. The only essential condition is that the coagulation index mentioned above is achieved.

After being treated with non-basic water, the yarn is once dried (
and finishing), it has a whiteness of 45 inches or more.

Whiteness (W) is measured using the Hunter method.
d) using a Hunter Lab device.

Coagulation index r r Ja mycellulose glucoside group 100
It is defined and calculated as the number of moles of C820 per unit.

Threads with an index r between 0 and 1 are considered completely coagulated.

The method of the invention therefore produces a viscose rayon yarn with high whiteness through the steps of partial coagulation and stretching, completion of coagulation, washing under the above-mentioned conditions, drying and general finishing. be.

Therefore, other treatments to improve whiteness are not recommended.
And in fact it is not possible to improve the whiteness any further. However, even if other auxiliary processing is performed in addition to the processing described above, this does not depart from the scope of the present invention.

This step is preferably carried out at a spinning speed, that is, at a spinning pull speed of e o a7+ or higher.

The above-mentioned washing is preferably carried out at a temperature of 20 to 30° C. for 25 to 40 seconds. Preferably, coagulation is completed in 15 to 40 seconds.

In one aspect of the invention, it is also important to define the chemical composition of the wash water that allows washing to be carried out under the conditions described above and to obtain the results described above.

Preferably, the voice of the water used is between 4.0 and 5.5.

Furthermore, Ca in the water is 1.5 W/j or less,
Mg2+ is 1. It is preferable that it is OQ/j or less.

It has been found that water with these properties can be obtained by treating industrial water with weakly acidic ion exchange resins, except in rare cases where this is already available. For treatment with resin, -4 to 5.5 for water;
Preferably, continue until you reach Fuku or 4.7.

Examples of the invention are described for illustrative purposes only. The cellulose paste to be dissolved, with an α-cellulose content of 921, was mercerized in 1896 NaOH and squeezed with a drawing ratio of 1:2.8t to produce the following: Obtain alkali cellulose of composition nine.

Cellulose: 32 g Total alkali expressed as NaOH: 15.79 G The alkali cellulose thus obtained was disintegrated and 3
It was aged until a degree of polymerization of 50 was obtained. After aging, the alkali cellulose is added to 30% C8 to cellulose.
Sulfated with 2.

The taxanate salt prepared in this way was diluted with dilute NaOH.
9. Dissolve in solution to obtain Y scose with the following composition.

Cell p-s: 8% Total alkali expressed as NaOH = 6. Total sulfur: 29 g The viscose thus obtained was spun in a spinning bath at 45° C. having the following composition to produce a yarn having a count of 133 dt·X.

Sulfuric acid: 140≠ Zinc sulfate: 101/1 Sodium sulfate: 250 lf The spinning process was carried out using a glass tube in which the coagulated yarn moved in the same direction as the coagulation bath. The thread was withdrawn from the bath and at this stage the r-index of the thread was 18. In the pulling-up stage, the thread is drawn by friction with the thread guide at a drawing ratio of 1 to 1.5 t. At this point, as described in Italian Patent Application No. 22076A/78, filed on April 7, 1978, a series of substantially helical structures on a device consisting essentially of a support and an advancement structure were developed. It begins to move through the passageway, during which time the system undergoes a series of chemical and physical treatments.

In the examples described above, the yarn was first subjected to natural syneresis and then treated in a curing bath consisting of a 151/JH,80 solution at 90°C. Afterwards, it was washed with water with a Mg ion content of 0°5119/J, treated with an emulsion of mineral oil, and finally It was dried and wound on a ring twister.

The physical properties of the yarn obtained in this way are as follows: 9. Strength in conditioned condition 18c approx. l@x Elongation rate in wet state 31% The features and advantages of this invention will become clearer from Table 1 which summarizes the analysis results of the yarn. In order to demonstrate the characteristics of the method of the present invention, it is preferable to carry out partial coagulation in a coagulation bath to complete the coagulation, instead of using the yarn obtained by the usual method, which requires a large number of operations and is slow in spinning speed. However, data for yarns that were not washed under the preferred conditions of this invention are also shown.

1; Measurement items are shown in [111] of Table 1.

The second column shows the results of the thread analysis after coagulation is complete. The whiteness was found to be 30, which is also the final yarn whiteness if only normal washing and finishing treatments were carried out. In that case, a separate bleaching operation would be necessary to improve whiteness.

The third column shows the properties of the yarn washed with distilled water after coagulation) J (7). Although the whiteness has been improved somewhat, despite using economically expensive distilled water. It can be seen that there are not enough and many cases.

Column 4 shows the properties of the yarn treated with the softening water of p) 18.2 after completion of coagulation. It can be seen that one value in this invention is preferable.

Columns 5 and 6 show data for two types of yarn treated with water treated with a weakly acidic ion exchange resin at pH 4.6 in accordance with the present invention. It can be seen that both have very high whiteness levels of 49 and 52, respectively. Comparing these data, it seems that the decisive factor is to reduce the sulfur content from sulfide. In fact, lowering the sulfur content improves whiteness, and other data appear to be independent of whiteness. However, this invention is not limited by any theory, and if the conditions of this invention are followed, a viscose rayon yarn with high whiteness can be obtained simply, more quickly, and more economically.

The method of the present invention and the conventional method are summarized in Table 2 to show the advantages of the present invention. The starting viscose is the same in both cases and the final whiteness is also the same. It can be seen that the conventional method involves the steps of handling, separating, and recovering a large amount of liquid, and is economically disadvantageous compared to the method of the present invention. Further, Table 3 shows the properties of nine threads obtained by the conventional method shown in Table 3 and the method of the present invention.

Claims (1)

[Claims] A continuous method for producing viscose rayon yarn, which comprises solidifying and then proceeding the filament in a substantially helical manner while subjecting the filament to the various treatments necessary for producing the final viscose rayon yarn. After taking out the filament from the coagulation bath, the coagulation is completed until the coagulation index becomes 1 or less, and the total sulfur content contained in the thread is 0.2 or less, and the sulfur bonded as sulfide is Content not more than 0.02 T, elemental sulfur not more than 0.0696, iron 40 pp
m or less, zinc is less than 700 ppm and lead is less than 30 ppm
1. A method for continuously producing viscose rayon yarn with high whiteness, characterized by treating it with non-alkaline water until it becomes less than pm. (2) The filament has a coagulation index of 15 to 25 when taken out from the coagulation bath.
The method described in section. (3) The method according to claim 1, wherein at least a part of the solidification is completed by simply leaving it to stand. (4) The method according to claim 1, wherein at least a part of the coagulation is completed by treatment with an acid bath. (5) The acid bath is a sulfuric acid solution, and the treatment is carried out at 50 to 100°C.
The method according to claim 4, which is carried out in (6) The method according to claim 1, wherein the drying and finishing are followed by treatment with water until the yarn has a whiteness of 459G or more. (7) Treatment with water at 20 to 30℃ for 25 to 4
The method according to claim 1, which is performed for 0 seconds. (8) A patent claim in which the treatment with water is carried out using water having -4.0 to 5,5 and a Ca2+ content of 1.5 Ml/J or less and a -21 content of 1.089 Ml/J or less. The method described in Scope 1. (9) The method according to claim 8, wherein the water is purified using a weakly acidic ion exchange resin. α1 The method according to claim 1, wherein the spinning is carried out at a yarn take-off speed of 94 threads or more.