JPH09268426A - Fiber manufacturing method - Google Patents

Abstract

(57) Abstract: A method for industrially producing a fiber from a DMSO-soluble polymer in a stable and inexpensive manner is provided. SOLUTION: In the wet or dry / wet spinning of a DMSO solution of a polymer into a methanol-based coagulation bath, the coagulation bath is composed of methanol, DMSO and water, and contains 40 to 70% by weight of methanol. The composition liquid whose content is 10 to 70% by weight based on the total amount of DMSO and water is used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a technique for industrially and stably producing fibers from a polymer dimethylsulfoxide (hereinafter abbreviated as DMSO) solution,
In detail, as a spinning method at that time, it is composed of three components of methanol, dimethylsulfoxide and water, the composition of which is 40% by weight or more and 70% by weight or less of water, and
A coagulation bath containing 10% by weight or more and 70% by weight or less of (dimethyl sulfoxide + water) is used.

[0002]

BACKGROUND ART It has long been known that DMSO has the ability to dissolve many polymers, and a DMSO solution of polyacrylonitrile is used as a spinning stock solution and spun in an aqueous coagulation bath to produce acrylonitrile fibers. Has already been implemented industrially. There are also many proposals in patents, for example, in JP-A-60-126313, a polyvinyl alcohol polymer (hereinafter abbreviated as PVA) is dissolved in DMSO, and this solution is dried in a methanol-based coagulation bath. Methods have been proposed for wet spinning to obtain high strength fibers. When this method is carried out, PVA is contained in the coagulation bath.
DMSO brought in from the solution will be included,
Therefore, the coagulation bath becomes a mixed solution of methanol and DMSO.

In a system in which the solvent and the coagulation bath are different as described above, when it is attempted to carry out this industrially, the coagulation bath liquid (mixed solution of DMSO and methanol in the case of the above method) is taken out from the coagulation bath, and both are removed. It becomes necessary to separate and reuse. If the methanol ratio of the coagulation bath is kept high, the amount of the coagulation bath liquid to be collected will increase and the recovery cost will increase. Although the above-mentioned patent describes that methanol, ethanol, and acetone are preferable as the coagulation bath, the mixed composition with DMSO is not described in detail. In addition, although the description of the ratio of DMSO / methanol is 10/90 to 5/95 in the examples, the D
At the MSO ratio, DMSO that the spinning solution brings into the coagulation bath
It is a concentration that will inevitably be reached at, and it is not a condition set in consideration of recovery costs. Even if the DMSO ratio of the coagulation bath is increased by paying attention to the recovery cost, the coagulation failure causes the fibers to stick to each other, or causes a process trouble such as roller winding. In order to avoid this, there is a method of lowering the temperature of the stock solution and the coagulation bath as much as possible, but the effect is not sufficient, which causes deterioration of the nozzle condition and further lowers the coagulation bath temperature, which also increases the utility cost. Connect

The present invention uses methanol, DM as a coagulation bath.
Although three components of SO and water are used in a specific composition, they are disclosed in JP-A-63-99315 and JP-A-64-7.
Japanese Patent No. 7616 proposes to use water as a solvent or extraction.

In the former, P having a degree of polymerization of 1500 or more is used.
VA was dissolved in a mixed solvent of water and DMSO having a weight mixing ratio of 5:95 to 60:40 to prepare a spinning dope, which was prepared in a mixed solution of DMSO and alcohol having a weight mixing ratio of 10:90 to 70:30. A method of extruding into (coagulation bath in the present invention) is disclosed. This method uses a coagulation bath containing no water. However, since water is inevitably brought into the coagulation bath from the spinning dope, it is impossible to industrially carry out the coagulation bath having the composition defined here. If the composition specified here is interpreted as the composition to be supplied to the spinning apparatus, spinning is possible, but since it contains water in the spinning, it cannot be circulated and used, and the running cost is extremely high. It becomes a process. It is virtually impossible to produce industrially.

For the latter, it is proposed that the same spinning dope as in the former is dried and wet-spun to form a yarn, and then the solvent in the yarn is extracted with a mixed solution of alcohol and water or a mixture of ketone and water. ing. For thread formation, a method of coagulating with an alcohol such as methanol or ethanol or a mixed solvent of these alcohols and a solvent of PVA and a method of gelling with a cooling medium such as paraffin oil or decalin are disclosed. Both of them are extracted with a mixed solution of alcohol and water or ketone and water after forming the filaments. This method differs from the present invention in which water is used in the coagulation bath for forming yarns. Further, as described above, the water brought into the coagulation bath or the cooling medium from the spinning dope is not considered at all, and this cannot be an industrial production process either. Furthermore, the method of using water for extraction, the degree of polymerization,
Even if it is applicable to PVA with a high degree of saponification,
For example, it is clear that when PVA having a low degree of saponification is spun, dissolution or sticking occurs in the extraction step,
It is not a versatile method that can be applied to various polymers.

[0007]

As described above, the conventional proposals lack the consideration of the material balance and have a high running cost, and cannot be established as an industrial production process. there were. It was also confirmed that if the coagulation bath composition was simply changed to DMSO rich as an extension of the prior art, coagulation would be insufficient when the methanol ratio was 70% by weight or less, and the polymer would elute in the bath or the fibers would stick. did. The present invention proposes a more industrially advantageous production means, and an object thereof is to provide, from a wide variety of polymers, stably and inexpensively, fibers having characteristics based on the properties of the respective polymers.

[0008]

[Means for Solving the Problems] That is, according to the present invention, a solution in which one or more polymers are dissolved in DMSO is discharged from a nozzle, introduced into a coagulation bath and coagulated to produce fibers. Methanol (A), DMS
It consists of three components, O (B) and water (C), and the composition weight ratio of (A) / [(A) + (B) + (C)] is 0.4-.
0.7 and (C) / [(B) + (C)] is 0.1
A method for producing fibers is characterized by using a mixed solution of about 0.7.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polymer used in the present invention is DM
It is not particularly limited as long as it can be dissolved in SO, PVA, polyacrylonitrile-based polymer (hereinafter abbreviated as PAN), polymethylmethacrylate-based polymer, ethylene-vinyl alcohol copolymer-based polymer,
Examples thereof include ethylene-vinyl acetate copolymer-based polymers, cellulose acetate-based polymers and carboxymethylcellulose-based polymers, but are not limited thereto. In particular, if the obtained fiber is required to have mechanical properties such as strength and elastic modulus and functions such as water solubility, PVA
Is preferred. If flame retardancy is required, polyvinyl chloride or a copolymer thereof may be used. If the polymer used has no fiber-forming ability, it may be used in combination with PVA having fiber-forming ability. Is. The degree of polymerization of PVA having a fiber-forming ability is 1,000 or more, preferably 150.
The degree of saponification is 0 or more and the degree of saponification is 85 mol% or more, and a copolymer of vinyl-based monomer containing carboxylic acid, ethylene and the like can be used, and can be appropriately selected according to the strength and water solubility of the target fiber. do it. Further, even PVA having a degree of polymerization or a degree of saponification that does not have a fiber-forming ability that deviates from the above range can be easily made into a fiber by mixing it with the above-mentioned PVA. Furthermore, PVA and PA
It is also possible to use two or more polymers that are incompatible with each other, such as N, cellulose acetate, and polymethylmethacrylate, to mix and use them to make fibers that can be divided, and to pulp the fibers by a method such as beating. Also, PV
A heat-bonding fiber can be obtained by combining A or PAN and a polymer having a different melting point such as ethylene vinyl acetate.

The fiberization of many of these polymers is based on DMS
Not only does O have an excellent dissolving ability, but the coagulation bath of the present invention can be used for stable and inexpensive processing. In order to reduce the recovery cost of the solvent, it is necessary to decrease the methanol ratio of the coagulation bath and increase the DMSO ratio to reduce the amount of the recovered liquid. However, this method cannot be simply adopted because the polymer is eluted in the bath or the fibers are stuck.

The thread forming mechanism in a system using DMSO as a solvent and methanol as a coagulating liquid is considered as follows.
Methanol in the coagulation bath is a non-solvent for the polymer dissolved in DMSO, and this penetrates into the DMSO solution of the polymer discharged from the nozzle, and the three-component composition of the polymer, DMSO, and methanol shifts to the methanol-rich direction. At certain compositions, the polymer becomes insoluble in DMSO and microcrystals form and gel. Here, if the methanol in the coagulation bath contains a large amount of DMSO, it takes a longer time to reach this gelling composition, during which the DMSO solution of the polymer (spinning stock solution) diffuses into the coagulation bath. This will be recognized as elution. In addition, the yarn formed in a coagulation bath with a high content of DMSO contains a large amount of DMSO inside the fiber, and it takes a long time to extract, and in some cases, it may be dried with poor extraction, causing sticking. Become.

Based on this idea, various studies were conducted on the composition of the coagulation bath. That is, as described above, DMSO is a good solvent having excellent solubility for many polymers, and if it is contained in the coagulation bath, its coagulation performance will naturally decrease.
Therefore, if DMSO is made a poor solvent, the coagulation performance should not be impaired. We investigated adding various organic solvents such as ketones to make DMSO a poor solvent, but the expected effect was not obtained. Surprisingly, the most effective means was to use water in the coagulation bath. It was found that it was to add. Then, as a result of examining suitable compositions from various viewpoints such as spinning stability, solvent recovery cost, and polymer elution prevention, the present invention has been accomplished.

The suitable composition of the coagulation bath thus grasped is composed of three components of methanol (A), DMSO (B) and water (C), and the composition is (A) / [(A) + (B) in weight ratio. )
+ (C)] is 0.4 to 0.7, and (C) /
[(B) + (C)] is 0.1 to 0.7. When the amount of methanol in the bath is less than 40% by weight, there is almost no filament forming ability, and when it exceeds 70% by weight, there is no problem in spinning technology.
The amount of coagulation bath liquid to be collected is very large and the collection cost is high. The water content is 10 with respect to the total amount of DMSO and water.
If it is less than wt%, the property of DMSO as a good solvent still remains, and it is difficult to set the methanol ratio to 70 wt% or less. On the contrary, in the region where the water content exceeds 70% by weight, the reason why the main component is PVA is not clear, but the gel obtained by coagulation devitrifies and the fiber strength is impaired. Alternatively, if water is a non-solvent for the polymer to be used, the coagulation of this polymer will proceed too much, resulting in loss of spinnability and frequent yarn breakage on the nozzle surface. The preferred composition is such that when the amount of methanol is 40 to 50% by weight, water / (DMSO + water) is 50 to 70% by weight, or the amount of methanol is 50 to 65% by weight.
Water / (DMSO + water) is 30 to 60% by weight, and the coagulation bath temperature is -10 to 30 ° C, especially 0 to 20% by weight.
C is preferred.

Although water is a solvent for a water-soluble polymer such as PVA, it is a poor solvent as compared with DMSO, and therefore mixing it in a coagulation bath enhances the coagulation performance.
Further, for a water-insoluble polymer soluble in DMSO,
Water is a completely non-solvent, and higher coagulation performance can be expected. Generally, the water-insoluble polymer soluble in DMSO is PVA.
Since the intermolecular force is weaker than that of, normal methanol / DM
Gelation due to crystallization hardly occurs in the SO-based coagulation bath.
For this reason, it was difficult to spin because of the large amount of elution into the coagulation bath.
By mixing water, the coagulability is dramatically improved.

The spinning method may be a wet method or a dry / wet method in which a gas layer is provided between the nozzle and the coagulation bath. The yarn formed in the coagulation bath is subsequently extracted with DMSO or water remaining in the fiber with methanol while being drawn 1.5 to 5 times, and an oil agent is added as necessary to dry.
After that, dry heat stretching and heat treatment may be performed, and if necessary, chemical treatment such as acetalization may be performed according to a usual method.

[0016]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, the composition ratio is a value based on weight.
The strength and elongation of the fibers in the examples are measured according to JIS L-1013, and the water dissolution temperature is 3 mm.
Put the cut fibers into water at a bath ratio of 1: 500 at 20 ° C,
It is defined as the temperature at which the fibers are completely dissolved when the temperature is raised at 2 ° C./minute while stirring.

Example 1 PVA having a polymerization degree of 1750 and a saponification degree of 97 mol% was added to DMS.
A stock solution for spinning was prepared by dissolving in O at 70 ° C. to a concentration of 18% by weight. This is 2000 holes, hole diameter 0.08m
wet spinning in a coagulation bath at 5 ° C. with a methanol / DMSO / water weight ratio of 60/25/15 through a m nozzle. Then, the mixture was stretched 3 times while extracting DMSO with 10 ° C methanol, and dried with hot air at 120 ° C.
It was stretched 2.7 times at 5 ° C. and wound up. No elution of PVA into the coagulation-extraction bath was observed, and the fibers obtained were 2800 denier / 2000 filaments, strength 7.8 g / d, elongation 13.5%, water dissolution temperature 65 ° C., between single fibers. The water-soluble fiber had good physical properties and quality without sticking.
Even when the coagulation bath was set to methanol / DMSO = 80/20, similarly favorable spinning was possible, but in this case, the solvent recovery cost required about 1.4 times that of this example. . It is clear that the significance of the present invention is not limited to obtaining fibers having a good process quality by simply adjusting the process conditions.

Comparative Examples 2 and 3 In Example 1, the coagulation bath composition was changed to methanol / DMSO /
Water = 60/40/0 (Comparative Example 1), 35/35/30
Spinning was performed in the same manner as in Example 1 except that (Comparative Example 2) was used. Even though the methanol / DMSO ratio of the coagulation bath was the same as that of Example 1, in the case of Comparative Example 1 containing no water, PVA was eluted into the coagulation bath and became cloudy, and the coagulation bath filter started spinning. It got stuck in about 5 hours. Also,
The obtained fiber had a lot of sticking and could not be put to practical use. On the other hand, in Comparative Example 2 in which the proportion of methanol in the coagulation bath was low, no yarn was formed in the coagulation bath and spinning was not possible.

Example 2 PVA having a polymerization degree of 2400 and a saponification degree of 99.8 mol%,
Polymethyl methacrylate having a degree of polymerization of 300 and ethylene-vinyl acetate copolymer having a degree of polymerization of 500 were mixed in a weight ratio of 6: 3: 1, and the mixed polymer was added at 23%.
Dissolved in DMSO at a concentration of 2000, 2000 holes, pore size 0.
Methanol / DMSO / water = 08mm nozzle
Wet spinning in a coagulation bath of 50/25/25 at 3 ° C,
Subsequently, it was stretched 3.5 times while extracting with methanol at 10 ° C., dried with hot air at 150 ° C., stretched 4.3 times at 230 ° C. and wound up. The process condition was stable, there was no elution of the polymer into the coagulation-extraction bath, and there was no sticking to the fibers obtained. The physical properties of this fiber are 3000 denier / 2000
Since it is a combination of filaments, strength 11.2 g / d, elongation 7.1% and incompatible polymer, it is microscopically phase-separable and can be divided, and contains ethylene vinyl acetate. Therefore, it was rich in functionality with thermocompression bonding.

Comparative Examples 3 and 4 In Example 2, the coagulation bath composition was changed to methanol / DMSO.
/ Water = 50/50/0 (Comparative Example 3), 50/10/40
(Comparative example 4). In Comparative Example 3, the elution of the polymer into the coagulation bath was particularly vigorous with polymethylmethacrylate, the bath became cloudy immediately after spinning, and the eluted polymer was deposited in the nozzle holes, resulting in a poor spinning condition. Further, the fibers were extremely sticky and could not be used. On the other hand, in Comparative Example 4, the polymethylmethacrylate coagulated excessively quickly, and the yarn was frequently broken near the nozzle surface, and spinning could not be performed.

[0021]

Industrial Applicability According to the method of the present invention, the production of fibers in a DMSO solvent / methanol coagulation system can be carried out inexpensively and stably for the first time.

Claims (2)

[Claims] 1. When producing a fiber by discharging a solution of one or more polymers dissolved in dimethyl sulfoxide from a nozzle and introducing the solution into a coagulation bath to coagulate fibers, methanol (A), dimethylsulfoxide ( B),
It consists of three components, water (C), and its composition weight ratio is (A).
/ [(A) + (B) + (C)] is 0.4 to 0.7 and (C) / [(B) + (C)] is 0.1 to 0.7 A method for producing a fiber, comprising: 2. The method according to claim 1, wherein the polymer is a polyvinyl alcohol polymer.