JPS6040102A - Preparation of viscose - Google Patents

Abstract

PURPOSE:To reduce an amount of CS2 used and to obtain viscose fittest for spinning, by using an alkali cellulose having a crystal part with specific properties, dissolving a reaction product of it with CS2 in an alkali aqueous solution under a specified condition. CONSTITUTION:(A) An alkali cellulose having an alkali cellulose crystal part with a crystal perfect degree B of alkali cellulose I crystal type {defined by the formula d(002)/d(202)-1[d(002) and d(202) are spacing of (002)plane and (202) plane, respectively} of >=0.04 is reacted with (B) 5-24wt% CS2 based on the component A, and the reaction product is dissolved in an alkali aqueous solution in such a way that the total alkali concentration of viscose dope at <=14 deg.C is 5- 16wt%, to give viscose. EFFECT:Viscose having improved transparency and low degree of substitution can be prepared with reducing degree of pollution as much as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing viscose, particularly viscose dope.

BACKGROUND ART At present, viscose (alkali solution of cellulose xanthate?ff1) is mostly used in the industrial production of regenerated cellulose fibers. However, it is still fresh in our minds that rayon manufacturing companies in Europe, America, Japan, and other countries have withdrawn one after another due to serious problems such as deterioration of the working environment and pollution caused by C82 and its byproducts. Even now, there is a strong sense of crisis about the very survival of the rayon industry, especially in the United States. Furthermore, in the rayon industry in the Soviet Union and Eastern Europe, there are countless reports of deteriorating working environments and the resulting effects on the human body. In response to such problems in the rayon industry, a method to obtain regenerated cellulose by dissolving cellulose in an organic solvent and making the system closed has been sought since 1972. However, it has become increasingly clear that these methods are not economically viable due to the toxicity, explosiveness and high cost of the solvent itself, as well as the low recovery efficiency of the main solvent. On the other hand, companies employing the conventional viscose process have paid as much attention as possible to the recovery method of C82 and its by-products. However, from the beginning
We did not come up with the idea of reducing the amount of 8. used. The reason for this is the rayon manufacturing process (acceleration, aging,
This seems to be because the changes in sulfidation, dissolution) are wide-ranging, and there are too many chemical and physicochemical factors to be elucidated, so emphasis has been placed on empirical knowledge. Under such circumstances, changing the technology once it has been industrially established poses a great deal of risk.

In consideration of this situation, the present inventors have intensively studied a method for producing a viscose dope suitable for spinning by minimizing the amount of C82 used, and have arrived at the present invention.

Purpose of the Invention The purpose of the present invention is to provide a method for producing a viscose dope suitable for producing regenerated cellulose filament, which reduces the amount of carbon disulfide (C82) used and minimizes the degree of pollution. do.

Structure of the Invention According to the present invention, the crystal redundancy ((d(002)/d
(202) )-1, l definition Sahir. Here, d(0
02) is the spacing between the (002) planes, and d(202) is the spacing between the (202) blood planes.
By reacting 24 g of carbon disulfide (C82), 14
A method for producing a viscose dope is provided in which C494 is dissolved in an alkaline aqueous solution such that the total alkali IJ fflt degree is 5 to 16 M at a temperature below .degree.

Detailed Description of the Structure of the Invention Conventionally, in the production of viscose for producing regenerated cellulose filaments, it was thought that fibers with few physical defects could not be obtained unless C82 was used in an amount of about 32 to 40% based on the weight of cellulose. There is.

In the case of fabrication, the residual physical defects are not fatal, so the amount of C82 used is 22 to 22% of the weight of cellulose.
Viscose dogu is produced at around 25%. The physical properties of the resulting fibers are primarily determined by the quality of the viscose dope used. The above empirical knowledge has led to the conclusion that it is almost impossible to produce dough f for filament production using less than 25% of C82 based on the weight of cellulose in rayon yarn, and in fact, there have been no industrially implemented examples. There isn't. The present inventors have detailed the various steps of rayon production.
+, and discovered a method for obtaining good viscose dough even with a small amount of C82, leading to the present invention.

The gist of the present invention is, firstly, to define alkali cellulose, and secondly, to establish a method for dissolving low-substituted xanthate by using low CS and Z. The first point is that the production of a good viscose dope with a small amount of undissolved cellulose and small amounts of
How to efficiently transform the crystalline part of alkali cellulose into C8
The second point is based on the idea of how to efficiently dissolve cellulose xanthate having an extremely low degree of substitution.

That is, the alkali cellulose used in the present invention has a crystalline portion of alkali cellulose I, and its crystal perfection B is C8.
Refers to 0.04 or more when reacting with 2. Here, the crystalline perfection of alkali cellulose I refers to cellulose obtained by converting cellulose into alkali cellulose under predetermined conditions and then squeezing the cellulose. Cellulose was evaluated by X-ray diffraction, and using the spacing between its (002) and (202) planes, d(002) and d(202), respectively, B
= d(002)/d(2,02)=1.

The theoretical value of the B value is 0 to 0.065.

Alkaline cellulose has various crystal systems.

For a long time, it has been said that alkali cellulose I crystal type is optimal for producing viscose.

However, the alkali cellulose conversion referred to herein does not refer to the cellulose immediately before being reacted with C82.

Particularly in conventional viscose production, alkali cellulose undergoes a long aging process. It is a well-known fact that alkali cellulose (■) transforms into alkali cellulose (■) over time.

Furthermore, even if there is a slight change in temperature during alkali cellulose formation (arcelization), alkali cellulose may even exhibit a mixed system of I and (2). Normally, in this case, the latter ratio is considered to be extremely small.

It is thought that what was conventionally called alkali cellulose (■) was also called alkali cellulose (■). The reason this did not become a problem when producing diviscose was because carbon disulfide was used extensively to dissolve xanthate with a degree of substitution of 0.5 or more.
When the amount of 2 is decreased, the crystallinity of the crystalline portion of the alkali cellulose greatly influences the state of the viscose dope after dissolution. Alkaline cellulose ■ has a wider unit crystal lattice spacing than other alkali cellulose crystals, and has a C8
This is advantageous when reacting with 2. If the degree of perfection B of the alkali cellulose summer crystal type in front of the reaction surface is smaller than 0.04, C8
2 was 20% by weight of cellulose, and there were many undissolved substances. The solubility of viscose after sulfidation and dissolution is λ = 660 nm.
Absorbance at A ((ci '', ?-'.

ae ): However, the concentration of L cellulose xanthate is the cellulose concentration? /de), then in the above moxibustion case A>
0.08, which does not provide very good solubility. In general, A is a measure of the transparency of a solution, but it is also a measure of stability over time. Generally, when A is 008 or less, it indicates a good viscose. As the amount of C82 used decreases to 5% per cellulose, a higher value of B is required. For example, for C821%, B≧0.056 is preferable. B≧
For example, alkali cellulose having a polymerization degree of 0.04 is obtained by preparing cellulose whose degree of polymerization is adjusted by an acid hydrolysis method at 60°C.
immersed in a 17-22% alkaline aqueous solution at ~20°C,
After pressing, the cellulose may be subjected to the sulfurization process without being left in the open for more than 2 hours, or the already aged alkali cellulose may be washed with water and then subjected to the sulfurization process again under the above conditions within 4 hours after acceleration. Alternatively, it can also be obtained by aging the pressed alkali cellulose obtained under the above conditions for alkali cellulose formation under a controlled steam atmosphere. The composition of the above alkali cellulose is 1.5 parts by weight of cellulose and 1.5 parts by weight of the immersed alkali aqueous solution.
Contains ~2M parts. The upper alkali cellulose is reacted with a weight of 2 to 5 to 24 M relative to the weight of the cellulose, and the reaction conditions can be selected as appropriate. For example, 2
4 rrmH? 1.5M at 40℃ under reduced pressure of 25℃
Then, it is sufficient to react for 2.0 hours. The degree of substitution (DS) of xanthate at the end of the reaction is usually 0.35 or less,
DS of xanthate (≧0.
56). For this reason, attention must be paid to the dissolution method, which is the second key point of the present invention. Usually, from an economical point of view, the original cellulose i in viscose dope is
It is desirable that mh is 8 to 12% by weight. The A value defined earlier in this n-degree range concavity (component-wise, 1 part of viscose after dissolution with the cellulose concentration adjusted to the above range is 9
is diluted with 2% NaOH aqueous solution and diluted with 2% N
The absorption C degree at λ = 660 nm was determined using an aOH aqueous solution as a control, and the cellulose xanthate contained in the sample viscose was regenerated by acid hydrolysis, and the absorption degree of the cellulose weight was determined. After the reaction, the same aqueous alkaline solution adjusted to below 14°C was used in order to make the absorbance (expressed as /de and the value obtained by dividing the previous absorbance by this value and the optical path of 0.5 cm) be 0.08 or less. Need to melt under temperature. At this time, the total amount of alkali (Na
1 l (e.g., ゛) 5-16% by weight gives a good dope.

In particular, poems and dogs with a total alkali content of 8 to 10% are very good, with an A value of 0.03 or less. When using this method, the amount of C82 used decreases, the more it becomes soluble.
It is desirable to lower the temperature (near 0°C) and to increase the total alkali content to 8 to 10 degrees. The minimum DS of cellulose xanthate after reaction that can be dissolved by this method is 0.05.
~0.03.

The viscose dough obtained by the present invention has better transparency than conventional viscose, has a lower degree of substitution, and can be used for spinning without the need for the conventional aging of viscose. It has advantages such as being able to Of course, the biggest effect is that gaseous by-products are reduced by half, and by-products during viscose regeneration are also reduced by half, which is an unprecedented effect in soil pollution prevention measures.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 This example shows an experimental example in which viscose was produced based on alkali celluloses having different B values.

The raw material cellulose is Alaska pulp
), 77. : /J /9 /l/p at 60℃ 5N
- ((2SO, soaked for 2 hours, washed with water, air dried (N
O,2,rJl13).

Three types of cellulose (14 [L4]) were used: aged alkali cellulose prepared by the method described later and regenerated with 2% H2SO4, washed with water, and air-dried. Table 1 shows the crystallinity and crystal morphology of the raw cellulose used in this experiment, as measured by seed 3L X-ray diffraction.

Raw material cellulose 102 is immersed in an 18% NaOH aqueous solution of 1002 at 25° C. or 55° C. for 30 minutes, compressed to a particle size of 7.282, and crushed using a household mixer.

Only NIL 1 was left in a heated atmosphere at 45°C for 5 hours.

This operation is called senescence and 11'J'-. N[L2. N[L3
．． Nα4 does not undergo aging and is immediately subjected to reaction.

The degree of polymerization (DP) of each alkali cellulose immediately before the reaction
; Measured by viscosity in Cadoxeno after regenerating cellulose) are shown in Table 1.

Immediately before the reaction, the alkali cellulose was compacted and the X-ray diffraction pattern was measured using the reflection method.λ = 0.154 nm.
42.5KV, 120mA), (002),
The B value was determined from the peak position of (202) ITll, and the values are shown in Table-1. N[L3. N14 corresponds to the present invention.

Table 1 Each of these alkali cellulose 282
50 ttrmH? Add 21 parts (22 parts by 11 parts to cellulose) of carbon disulfide under reduced pressure, and leave at 40°C for 2 hours with occasional shaking.

The reaction product thus obtained was heated to 5.9% Na at 4°C.
When dissolved in 0I-I aqueous solution 722, the polymer concentration in terms of cellulose is 9.0% by weight, total alkali (NaOH
viscose with a concentration of 8% by weight) is obtained.

Table 1 shows the A value of viscose in each experimental example and the natural solidification time when left at 50°C. Nα3゜N[L4
(the present invention) is Nα1. A good viscose with higher transparency and stability than N[L2 (comparative example) was obtained.

Example 2 This example shows an experimental example in which the temperature at which the reaction product of alkali cellulose and carbon disulfide is dissolved in an aqueous alkaline solution is different.

Viscose was produced by a method similar to Example INu4, with the melting temperature unchanged. Table 2 shows the melting temperature, A value, and natural solidification time at 50°C for each experimental example. Nα4°Mll5 having a melting temperature of 14°C or lower (the present invention)
Then, tl(L 1 , N[L2,
The transparency and stability of the dope were significantly improved compared to N[L3 (comparative example)].

Example 3 This example shows that from viscose synthesized by the method of the present invention,
This shows that fibers with desirable physical properties can be obtained by wet spinning.

The method for producing viscose is based on Example 1, Nα4. However, the amount of carbon disulfide used was 11 to 102 of the raw material cellulose, and the total degree of substitution (DS) of cellulose xanthate in the viscose in this case was 0.099.

The dope with 0.0
From a spinneret with 50 holes of 8 mm diameter, about 1
It was discharged at a pressure of ATM, wound up at a speed of 9.7 m/=, washed with water, and dried to obtain regenerated cellulose fibers. The composition of the coagulation bath was H2SO, 40ff/L, Na, So,
.

2609/l and ZnC4414fl/l.

The obtained fibers had a tensile strength of 14 to 1.69/d.

The elongation was 11 to 15%, the modulus of elasticity was 43 r/d, and it had desirable physical properties as a clothing fiber.

patent applicant Asahi Kasei Industries, Ltd. patent application agent Patent Attorney Official Ki Akira Patent attorney Kazuyuki Nishidate Patent attorney Tsuyoshi Yoshida Patent attorney Akira Yamaguchi Patent Attorney Masaya Nishiyama

Claims (1)

[Claims] 1. Alkali cellulose in the alkali cellulose crystal part ■Crystalline perfection of the crystal form ((d(002)/d(2o2)
)-1. Here, d(002) is (0
02) The lattice spacing of blood, d(202) is the lattice spacing of the (202) plane) For alkali cellulose where B satisfies B2O, 04, carbon disulfide in an amount of 5 to 24% of the weight of the cellulose. A method for producing a viscose dope, which comprises reacting (C82) and dissolving it in an alkaline aqueous solution at 14° C. or below so that the total alkali rotation becomes 5 to 16% by weight.