JPS60209006A - Method for spinning cellulose - Google Patents

Abstract

PURPOSE:To obtain cellulose fiber products of high quality at a low cost without causing pollution, by dissolving collulose in a specific solvent, and extruding the resultant cellulose solution into a regenerating solution under specific conditions to spin efficiently the cellulose. CONSTITUTION:Cellulose is first dissolved in an organic solvent, preferably dimethyl sulfoxide containing a tetraalkylammonium halide of the formula R4NX (R is 1-3C alkyl; X is halogen), e.g. tetraethylammonium bromide, and the resultant cellulose solution is kept at 10-70 deg.C, extruded through a spinning nozzle at 40-70 deg.C tip temperature into a regenerating solution consisting of an aqueous medium, e.g. water or aqueous solution of NaCl, and spun into cellulose fibers. After the extrusion, the tetraalkylammonium bromide stuck to the cellulose is preferably removed completely with hot water at 30-60 deg.C to give the aimed products of better quality.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for spinning cellulose, and more specifically, by spinning a cellulose solution prepared by dissolving cellulose in six specific solvents into a regenerating solution under certain conditions, cellulose can be efficiently spun. It relates to a method for spinning and obtaining cellulose fibers or filaments of excellent quality.

Conventionally, various methods including the viscose method have been known for producing regenerated cellulose fibers or filaments by spinning a cellulose solution obtained by dissolving cellulose in an organic solvent into a regenerating liquid. However, these methods have drawbacks such as the organic solvent used to dissolve cellulose is itself a pollutant, it is expensive, it is difficult to handle and recover, and the resulting fibers or filaments are There were various problems such as not having sufficiently satisfactory quality and poor spinning efficiency.

Therefore, the present inventors solved the problems of the above conventional method, and
We conducted extensive research to develop a method for dissolving cellulose using low-cost, non-polluting organic solvents and efficiently producing high-quality cellulose fibers or filaments. As a result, while using a solvent containing tetraalkylammonium halide as an organic solvent for dissolving cellulose, and controlling the temperature of the cellulose solution and the temperature at the tip of the spinning nozzle within a predetermined range, the cellulose solution was spun from the spinning nozzle into the regenerated liquid. I found that I could achieve my goal by letting them come out. The present invention was completed based on this knowledge. That is, the present invention involves dissolving cellulose in an organic solvent containing a tetraalkylammonium halide represented by the general formula R4NX (wherein R represents an alkyl group having 1 to 3 carbon atoms and X represents a halogen atom). A cellulose spinning method characterized by spinning a cellulose solution maintained at 10 to 70°C from a spinning nozzle with a tip temperature of 40 to 70°C into a regenerating liquid consisting of water or an aqueous medium. This is what we provide.

In the method of the present invention, cellulose is spun by spinning a cellulose solution into a regeneration solution under certain conditions.
The cellulose solution used here is prepared by dissolving cellulose in an organic solvent containing tetraalkylammonium halide.

As mentioned above, the tetraalkylammonium halide is represented by the general formula R4NX, and specifically includes tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride, methyltriethylammonium chloride, propyltriethylammonium chloride, or a mixture thereof. etc.

Various organic solvents can be used, but those that can dissolve the above-mentioned tetraalkylammonium halide are usually preferred, with dimethyl sulfoxide being the best, and tetramethylene sulfoxide etc. also preferred. Furthermore, it is also effective to use pyridine or dimethylformamide mixed with dimethylsulfoxide.

The concentration of the tetraalkylammonium halide in the above-mentioned organic solvent may be adjusted as appropriate depending on various conditions, but it should normally be 15 to 45% by weight, preferably 20 to 30% by weight. In particular, when using dimethyl sulfoxide, which has a large dissolving power, as an organic solvent, cellulose cannot be rapidly dissolved even if the concentration of tetraalkylammonium halide such as tetraethylammonium chloride is kept as low as 15 to 25% by weight. can. In this way, by lowering the concentration of tetraalkylammonium halide, precipitation of the tetraalkylammonium halide can be avoided when cellulose is spun in a regenerating solution, so that high-quality cellulose fibers or filaments can be obtained. In this case, it is also possible to lower the dissolution temperature of cellulose, which is effective in preventing a decrease in the degree of polymerization of the cellulose to be dissolved. The tetraalkylammonium halide-containing organic solvent used to dissolve cellulose may contain 2% or less, preferably 1 to 0.1%, of water.

In addition, when dissolving cellulose in an organic solvent containing a tetraalkylammonium halide, it is important to heat the solution to a temperature that can sufficiently and quickly dissolve cellulose and that does not reduce the degree of polymerization of cellulose. Specifically, it varies depending on the concentration of cellulose to be dissolved, the type and concentration of tetraalkylammonium halide, and the type of organic solvent, but it is usually 50 to 100°C, preferably 70 to 90°C.
Most preferably, the temperature is 75 to 85°C.

The concentration of cellulose in the cellulose solution obtained here differs depending on the conditions, but in order to smoothly proceed with the spinning process in the regenerated solution, the concentration of cellulose is preferably 5 to 15% by weight, and especially the range of 7 to 10% by weight is most preferable. preferable. This is a higher concentration of cellulose than in conventional methods, and therefore, according to the spinning method of the present invention using this cellulose solution, it is possible to efficiently spin a large amount of cellulose in a short time.

In the method of the present invention, cellulose fibers or filaments are produced by spinning the cellulose solution prepared as described above into a regeneration solution. ~100℃,
Preferably, it is necessary to keep the temperature at about 40 to 80℃. When the temperature exceeds 100'C, the degree of polymerization of cellulose decreases. Further, if the temperature is lower than 2°C, there is a problem that tetraalkylammonium halide precipitates.

This heated cellulose solution is allowed to stand as desired,
After defoaming under a reduced pressure of about 40 mm Hg, it is spun into a regenerating solution from a spinning nozzle. At this time, the temperature at the tip of the spinning nozzle should be maintained in the range of 40 to 70°C, preferably 40 to 60°C. By maintaining the nozzle tip temperature within a predetermined temperature range in this manner, precipitation of tetraalkylammonium halide is prevented during the spinning process, and the spinning process proceeds smoothly.

If the nozzle tip temperature is too high, fibers are likely to break during regeneration (on the other hand, if it is too low, tetraalkyl ammonium halide may precipitate, leading to nozzle clogging and quality deterioration of the resulting cellulose fibers or filaments. There is a risk.

In the method of the present invention, water or an aqueous medium is used as the regeneration liquid for spinning the cellulose solution. Various types of aqueous media can be used here, including sodium chloride and sodium sulfate.

Potassium chloride, sodium bromide, potassium bromide.

Examples include aqueous solutions containing one or more inorganic salts such as sodium phosphate and sodium hydrogen phosphate in a proportion of about 5 to 30%. Using such an aqueous solution makes it possible to increase the spinning speed of cellulose.

In the method of the present invention, when spinning the cellulose solution from the spinning nozzle into the regenerated solution, nitrogen gas etc.
A pressure of about 4 kg/cm" is applied to the nozzle to discharge the cellulose solution into the regenerated liquid, and the cellulose solution is poured into the regenerated liquid at a distance of 20 to 100 cm.
Pass through the regenerating liquid and pull it, then 10 to 50 cm.
It is enough to wind it up at a speed of /second. Here, the temperature of the regenerating solution is not particularly limited and may be determined as appropriate depending on the operating conditions, etc., but the temperature distribution should be such that the temperature gradually becomes lower with a temperature gradient from the tip of the spinning nozzle along the spinning direction of the cellulose solution. and further set the final temperature (i.e. minimum temperature) to 10 to 40
It is preferable to keep the temperature at about ℃.

In the method of the present invention, cellulose fibers or filaments can be continuously and efficiently produced by spinning a cellulose solution into a regenerating solution and winding it up. 30-60℃ before
If the tetraalkylammonium halide adhering to the spun cellulose is completely removed by passing it through moderately warm water, cellulose fibers or filaments of even better quality can be obtained.

As described above, according to the method of the present invention, high quality cellulose fibers or filaments can be efficiently produced at low cost and without pollution. Furthermore, after spinning cellulose, it is easy to recover the tetraalkylammonium halide and the organic solvent from the regenerating solution.

Therefore, the method of the present invention is of extremely high value industrially as a method for producing high quality cellulose fibers or filaments.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A DP90G sulfide pulp for viscose was cut into small pieces and dried under reduced pressure at 90° C. for 3 hours to obtain raw material cellulose.

On the other hand, commercially available tetraethylammonium chloride anhydride was added to dimethyl sulfoxide to a concentration of 40% by weight, heated to 90 to 100°C to dissolve, and then the raw material cellulose was added and heated at 90 to 100°C. After stirring for 1 hour, a cellulose solution having a concentration of 6% by weight was obtained.

Subsequently, this cellulose solution was further heated and left at 90°C for 1 hour, then defoamed under a reduced pressure of 40 V++ Hg, and kept at 80°C. From the spinning nozzle, the nitrogen pressure is 5 kg.
/cIIl! was spun into water. The spun cellulose was passed through water for about 30 cm, and then passed through water for 20 cm/
The cellulose filament was obtained by winding at a speed of seconds. The properties of this filament maintained the degree of polymerization of the raw material cellulose and had extremely high strength. Note that the temperature distribution of water, which is the regenerating liquid, is set at 50°C near the tip of the spinning nozzle, and with a temperature gradient of 1'c/cm along the cellulose spinning direction, with a minimum temperature of 1'c/cm.
The temperature was adjusted to 0°C.

Claims (7)

[Claims] (1) Cellulose is dissolved in an organic solvent containing a tetraalkylammonium halide represented by the general formula R4NX (wherein R represents an alkyl group having 1 to 3 carbon atoms and X represents a halogen atom). , and 10-70°C
The cellulose solution held at a tip temperature of 40 to 70
1. A method for spinning cellulose, which comprises spinning cellulose from a spinning nozzle at 0.degree. C. into a regenerating solution consisting of water or an aqueous medium. (2) The method according to claim 1, wherein the organic solvent containing tetraalkylammonium halide for dissolving cellulose contains 2% or less of water. (3) Claim 1 in which the organic solvent is dimethyl sulfoxide and/or tetramethylene sulfoxide.
The method described in section. (4) The method according to claim 1, wherein the organic solvent is a mixture of dimethyl sulfoxide and pyridine or dimethylformamide. (5) The method according to claim 1, wherein the concentration of tetraalkylammonium halide in the 198 agent is 15 to 45% by weight. (6) The regenerating liquid contains thorium chloride, sodium sulfate,
Claim 1 is an aqueous solution containing one or more inorganic salts selected from the group consisting of potassium chloride, sodium bromide, potassium bromide, sodium phosphate, and sodium hydrogen phosphate. the method of. (7) Gradually lowering the temperature of the regenerating solution from the tip of the spinning nozzle along the spinning direction of the cellulose solution,
Claim 1 in which the minimum temperature is maintained at 10 to 40°C
The method described in section.