JPS61275411A - Production of spinning stock solution - Google Patents

Abstract

PURPOSE:To obtain the titled stock solution having uniformity free from unevenness of viscosity, causing neither end breakage nor modified yarn during spinning, by pretreating a mixed solution of a polymer, a solvent and a non-solvent, blending the solution while stirring, and heat-treating the blend. CONSTITUTION:A polymer such as cellulose diacetate, etc. is added to a system of a solvent such as N-methylpyrrolidone, etc. and a non-solvent such as ethylene glycol, etc., and the solution is allowed to stand at a low-temperature so that it is treated at low temperature. Then, the solution subjected to the low- temperature treatment is blended while stirring and, further heat-treated to give the aimed spinning stock solution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for preparing a spinning dope that can maintain a substantially uniform dissolution state.

(Prior Art) In preparing a spinning stock solution (dope), it is essential that a uniform dissolution state can be maintained1. Therefore, various dissolution conditions have been studied. In particular, when a dope is prepared using a multi-component system, its dissolution poses a more complicated problem. In other words, instead of simply dissolving the polymer in a solvent, 1 may also add a non-solvent, etc.
In multi-component systems, it has been difficult to obtain a uniform spinning solution because the polymer has microscopic interactions with not only the solvent but also the non-solvent and both.

(Problems to be Solved by the Invention) The solubility of this spinning stock solution affects the stability of spinning after the preparation of the stock solution and the properties of the final fiber.1 In particular, when preparing a multi-component spinning stock solution, As a result of intensive study on conditions that could provide stable and uniform micro-solubility,
The present invention has been discovered.

(Means for Solving the Problems) That is, in producing a spinning dope from a polymer, a solvent and a non-solvent, the present invention involves: 1 treating the polymer, solvent and non-solvent at a low temperature in advance; It is characterized by doing.

In other words, when a dope prepared by mixing a polymer, a solvent, and a nonsolvent is immediately stirred and heated, a uniform dissolution state is not obtained. This is presumed to be due to the sequential nature of the interaction between the polymer, solvent, and nonsolvent.

In the case of the present invention) it is necessary to first add the polymer to the solvent 1 non-solvent system and carry out the treatment at low temperature. In this case, dissolving the polymer involves weighing out a calculated amount of polymer in advance, mixing it and leaving it for a while.The treatment temperature is 5 to 50 degrees Celsius, preferably 5 to 35 degrees Celsius, and the treatment temperature is at least 50 degrees Celsius. The treatment is carried out for 2 hours, preferably overnight. By performing such low-temperature treatment, the polymer can be swollen by the solvent or non-solvent, and the molecules in the swollen particles can be dispersed. At this time, slow stirring (for example, several times per minute) may be performed at the same time. By this stirring, the polymer molecules loosened as described above are dispersed more uniformly, and the polymer can have microscopic interactions with the solvent 1 and the non-solvent.

It is necessary to bring the material into such a melted state beforehand before carrying out the heat treatment. By doing so, the mutual exchange between states exhibiting multi-song interactions is rapid, resulting in a substantially uniform dissolution state. There are no particular limitations on the heat treatment conditions, but the temperature must be higher than that during the low temperature treatment.

By employing such a multi-stage treatment, a metastable microphase interaction is first performed between the polymer, solvent, and non-solvent to develop a φ state (weak heterogeneous dissolution state), and then heat treatment is performed. By strengthening the dissolution conditions and unifying the interaction, uniformity and stabilization of the dope can be achieved.

In addition, in the present invention, polymers such as cellulose acetate, cellulose triacetate, cellulose nitrate, etc.
- A combination of a solvent such as methylpyrrolidone, dimethylformamide, acetone, etc., and a non-solvent such as ethylene glycol, glycerin, or polyethylene glycol is used, but is not limited to these.

Furthermore, the dissolution uniformity of the spinning stock solution was measured by nuclear magnetic resonance (described later) (
Lsa-xMR).

(Effects of the Invention) By employing the method of the present invention, the viscosity non-uniformity of the spinning dope, which has often been a problem, has been eliminated, and the occurrence of yarn breakage and irregularly shaped yarn during spinning has been suppressed. At the same time, the operability and stability of spinning were significantly impaired.

Furthermore, there was an advantage that the replacement life of the filter during spinning was extended.

(Example) Examples of the present invention will be described below.

Examples and Comparative Examples N-methylpyrrolidone (liMP) was weighed as a solvent so that the final proportion was 50% by weight, and ethylene glycol (me) was weighed as a non-solvent so that the final proportion was 20% by weight. ) and mix. Heptylulose diacetate weighed out so that the final proportion was 30% by weight was added thereto, and the mixture was allowed to stand overnight at room temperature with slow stirring. 110- of the dope sampled in this state
The MMR measurement results are shown in FIG. In Figure 1, N
- The carbonyl carbon of methylbiwalidone showed a signal in which it was split into several parts, indicating that in this state it was in a metastable state with two or more types of interactions between the polymer solvents, exhibiting a heterogeneous appearance. It shows. This dope was stirred and dissolved at 100° C. for 12 hours, and then at 120° C. for 12 hours, and sampled again. The measurement results of O-NMH are shown in FIG.

In FIG. 2, it was confirmed that one polymer solvent and one non-solvent were in a substantially uniform state without exhibiting multiple interactions with each other. This dope also had good filterability.

As a comparative example, 1 was used directly without leaving overnight as in the above example.
The dope was heated to 20℃ and stirred and dissolved for 14 hours.
The O-NMR measurement results are shown in FIG. In this case as well, it is shown that it is in a non-uniform state as in FIG. Figure 4 shows the O-NMR measurement results of this dope, which was further stirred and dissolved at 120°C for 6 hours. The carbon signal is split into three lines, indicating that it is in a non-uniform state due to multiple interactions between the polymer, solvent, and non-bath medium, which is different from the cases in Figures 1 and 3. As described above, in the comparative example, even though the heat treatment was performed for a longer time than in the example, a uniform state could not be obtained.

Therefore, in the method of preparing a uniform dope, the importance of leaving the product at room temperature before raising the temperature as shown in the example is shown.

The method for measuring "O-0-1l" is shown below.

"O-NMR measurement conditions■ Sample: Place approximately 2- of the sample into an 8-φ NMR sample tube, taking care not to introduce air bubbles, and then add this sample tube to the D
The sample is placed in a 10-φ MMR sample tube containing about 14 MSO-(1, 1,000000000000000000000000000000000000000000) and has a double structure.

■ NMR spectrum measurement (Measurement nucleus 130 (Frequency) & 5 M) I,
z(1) Measurement temperature 60℃ (lv) 15~20"
pulse (v) spectral width 0-200 ppm (Vl) proton omplete decouple
ing

[Brief explanation of the drawing]

1 to 4 are nuclear magnetic resonance measurement charts for the method of the present invention and a comparative example. Patent applicant: Toyobo Co., Ltd. (II?3g) (62,4) 11! + (48,1) (lQ35) (28,0)
(16,4) PPpfL early 21!1 early 3 concave early 41!1

Claims (1)

[Claims] A spinning stock solution is produced from a polymer, a solvent, and a non-solvent, which is characterized in that the polymer, solvent, and non-solvent are treated at a low temperature in advance, and then stirred, mixed, and heated. Production method.