JPS58214513A - Production of chitin yarn - Google Patents

Abstract

PURPOSE:In subjecting chitin dope to wet spinning, to obtain chitin yarn useful as absorbing surgical suture having improved strength in good spinning conditions, by regulating the temperature of a coagulation bath in a specific temperature range. CONSTITUTION:Preferably 1-10wt% chitin dope consisting of chitin and a solvent [preferably mixed system of trichloroacetic acid and a chlorinated hydrocarbon in a weight ratio of (25-75):(75-25)] is spun into a coagulation bath at 10- 45 deg.C, preferably 20-40 deg.C coagulation bath temperature. The filaments are drawn to give the desired chitin yarn having >=3.5g/d dry strength. Acetone, methanol, or ethanol is preferable as the cogulation solvent.

Description

[Detailed description of the invention] The present invention relates to a method for producing chitin fibers.

Chitin is a natural polymeric substance that is present in the exoskeleton of crustaceans such as crabs and shrimps, as well as in the cell walls of mushrooms and fungi. It is a polysaccharide consisting of glucosamine) and has a structure similar to cellulose. Therefore, attempts have been made to use it in fibers and thin films for a long time, but since each repeating unit of the molecule has one acetylamino group, it has a crystal structure due to extremely strong intermolecular forces. It has the property of being almost insoluble in inorganic and organic solvents. However, because it contains an acetylamino group, it has many interesting and unique properties. It is said that chitin has good dyeability, and for this reason, it has been proposed to make chitin into fibers and use it as absorbable surgical suture thread.

Conventionally, various methods have been proposed for producing fibers by mixed spinning of chitin dope. is not known. For example, in JP-A-51-13367, chitin dope is prepared by dissolving chitin in a solution containing trichloroacetic acid,
It is described that chitin fibers with high strength were obtained by wet spinning and cold drawing this material, but there is no mention of the coagulation bath temperature, and furthermore, there is no mention of improving the particles by adjusting the coagulation bath temperature. I haven't stopped thinking about it again. In Japanese Unexamined Patent Publication No. 53-126090.

It is described that chitin fibers were obtained by dissolving chitin in a solvent such as dichloroacetic acid to produce chitin dough, which was then wet-spun and then drawn.

However, the strength of the obtained fibers was as low as 1.2 to 1.52 ha, and #! There is no mention of improving the mechanical properties or particles of fibers by adjusting the humidity of the solid bath.

In view of the current situation, the present inventors have conducted intensive research with the aim of providing a method for producing chitin fibers with excellent mechanical properties.As a result, when spinning chitin fibers, l#! The present invention has been achieved by discovering that the above object can be achieved only by adjusting the solid bath temperature to a range of 0 to 45°C.

That is, the present invention is a method for producing chitin fibers containing chitin and a solvent.

According to the present invention, an appropriate coagulation rate can be obtained by adjusting the coagulation bath temperature within the above range.

The effects are remarkable, such as making it possible to produce highly strong chitin fibers with a dry strength of 2 yAl or more.

The chitin used in the present invention includes not only chitin itself but also chitin derivatives. Chitin used in the present invention is prepared by, for example, treating the exoskeleton of crustaceans, insects, etc. with hydrochloric acid and hydrochloric acid to remove calcium and protein beforehand, purifying and pulverizing the exoskeleton.

Although various known chitin solvents can be used as the solvent for preparing the chitin dope in the present invention, trichloroacetic acid is particularly preferably used. Since trichloroacetic acid has a melting point of 57°C, K needs to be maintained at at least 57°C or higher in order to obtain a chitin dope. Since chitin decomposes to some extent at such temperatures, it is desirable to use trichloroacetic acid as a solvent together with an organic solvent that dissolves trichloroacetic acid preferably at 50° C. or lower, more preferably at room temperature or lower. Examples of solvents that dissolve trichloroacetic acid and provide a uniform chitin dope at room temperature include chlorinated hydrocarbons.

Preferred chlorinated hydrocarbons include, for example, chloromethane, dichloromethane, chloroform, carbon tetrachloride, 1.
Examples include 2-dichloroethane, 1,1.1-1-dichloroethane, and 1,1.2-)dichloroethylene, which may be used alone or in combination of two or more. can. The mixing ratio of trichloroacetic acid and chlorinated hydrocarbon is preferably in the range of 25 to 75: to 25 (weight ratio). Further, co-solvents such as tositechloral and chloral hydrate can also be used.

The chitin concentration in the chitin dope is preferably 05-20
% by weight, preferably 05-10% by weight.

More preferably, it is 1 to 10% by weight. If the concentration of chitin becomes too high, it will be difficult to dissolve it, and it will also be difficult to produce fibers from such chitin dope.
If it is too low, it becomes difficult to obtain fibers with excellent mechanical properties, which is undesirable.

In order to produce chitin fibers according to the present invention, a chitin dope as described above is first prepared, and preferably one
Chitin dope heated to over 0℃.

It is necessary to extrude the material through a nozzle into a coagulation tank adjusted to 10 to 45°C and take it off.

Examples of coagulation baths used in the present invention include acetone,
Organic ketones such as methyl ethyl ketone, methyl imbutyl ketone, diethyl ketone, and cyclopentanone, ethylene chloride, and carbon tetrachloride.

Chlorinated hydrocarbons such as trichlorethylene.

Hydrocarbons such as cyclohexane, hexane, petroleum ether, alcohols such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, alcohols such as ethyl acetate, esters such as ethyl acetate, dimethylformamide, N-methylpyrrolidone, etc. Among these, acetone, methanol, or ethanol is particularly preferred.

In the present invention, it is necessary to adjust the bath lagoon to a range of 10 to 45°C. At a temperature lower than 10°C, the solidification rate is slow. + At a take-up speed of 21 rθ or higher, single filament breakage occurs frequently on the nozzle surface, resulting in poor particle quality. Also,
At temperatures higher than 45°C, the coagulation rate increases and the strength of the resulting chitin fibers is low. Furthermore, when an organic solvent or agent such as acetone or methanol is used in the coagulation bath, if the temperature of the coagulation bath becomes high, there are problems in operability such as safety and hygiene.

Chitin fibers with excellent mechanical properties are called particles.
In order to obtain
It is necessary to adjust the temperature to a range of 40°C.

In the present invention, if the yarn formed by pressing as described above still contains a part of the solvent.

Furthermore, it is preferable to introduce the yarn into a second coagulation bath adjusted to the above-mentioned temperature for treatment. In this case, it is preferable to process the yarn in a state where substantially no tension is applied to the yarn. Specifically, during the second coagulation process, a conveyor is provided that moves at a slower speed than the speed at which the yarn is taken from the first coagulation bath, and the yarn taken from the first coagulation bath is introduced onto this conveyor. After solidification has progressed, a method can be adopted in which the material is taken off using a take-up roller.

The fibers obtained as described above have crystalline strength as they are, but by stretching them, fibers with even higher strength can be obtained. Stretching may be performed subsequent to treatment with a coagulating solution, and then the film is twisted. This can be carried out after neutralization and washing, and various known devices can be used. For example, stretching can be performed by about 20 to 80% of the original length.

According to the present invention as described above, the particle 〈2〉 or more, preferably 2.5 (//
It is TiJ's ability to obtain chitin fibers having a dry strength of p/d or more, preferably 3.5 j//(1 or more).

It is particularly preferred as a fiber for preparing absorbable surgical sutures.

Hereinafter, the present invention will be specifically explained using actual winding examples.

Note that the dry strength in one example was measured using an Instron tensile tester at 25°C, 960% F, H, and under a flume.

Example 1 ′″“′ Powder [Republic type, IJVi1@], molecular weight approximately 1
A chitin dope was obtained by dissolving 3 parts by weight of [1,000,000] in a mixed solvent consisting of 50 parts by weight of trichloroacetic acid and 50 parts by weight of methylene chloride at 5'C. This dope is 1480
After filtering the dope under a pressure of 4 KV using a mesh stainless steel wire mesh, the dope was sufficiently degassed under reduced pressure and transferred to a tank. The dope was then pumped with a gear pump under a pressure of 2.5 Kmi and the pore size Q, Q7 wg, discharge amount 1.70n11 from a nozzle with 50 holes! /min to form a yarn into acetone (first coagulation bath) whose temperature is controlled at 18 ° C.
It was picked up by rollers at a speed of 5 minutes. 1.
It was guided onto a conveyor placed in methanol temperature-controlled at 8°C, treated for 10 minutes, and then wound up with a winder at a speed of 4.5W. The wound yarn was neutralized, washed, and dried to obtain chitin fibers. Spinning was carried out for 5 hours, during which time there was no yarn breakage and the particle quality was very good. The obtained chitin fiber has a total denier of 1
It had a single yarn denier of 5Qa, a single yarn denier of 3d, a dry strength of 2.65yβ, and a residual elongation of 25.6%.

Comparative Example 1 Spinning was carried out in the same manner as in Example 1 except that the coagulation bath temperature was set at 8°C, but the coagulation rate was slow and single filament breakage occurred, making spinning impossible.

Comparative Example 2 A fiber was spun in the same manner as in Example 1, except that the coagulation bath temperature was set at 46° C., and the fiber was wound up using a soinder. The wound yarn was neutralized, washed, and dried to obtain chitin fibers. The particles were good, but the chitin fibers had a total denier of 1.
53d, single thread denier 3.06d.

The dry strength was 1.7 byA and the residual elongation was 14.7%.

Example 2 4.5 parts by weight of chitin powder (molecular weight approximately 1 million).

Example 1 was added to a mixed solvent consisting of 40 parts by weight of trichloroacetic acid, 40 parts by weight of trichlene, and 20 parts by weight of chloral hydrate.
After dissolving, filtering, and defoaming in the same manner as above, transfer to a tank.
After controlling the temperature of the dope to ℃, it was pumped with a gear pump under pressure of 4 kg//- to make the pore size 0. The yarn was spun into acetone whose temperature was controlled to 25° C. at a discharge rate of 1.01 rTl/min from a Q7tm nozzle with 30 holes, and was taken up by a roller at a speed of 7.5r19. The taken yarn was post-treated in the same manner as in Example 1 to obtain chitin fibers. Spinning was carried out for 6 hours, and the particle quality was good. The chitin fiber obtained had a total denier of 75 d, a single yarn denier of 2.5 d, a dry strength of 3.08 p/d, and a residual elongation of 207%. there were.

Example 6 6 parts by weight of chitin powder (approximately 100 molecules) was dissolved in a mixed solvent consisting of 50 parts by weight of trichloroacetic acid and 50 parts by weight of trichlene in the same manner as in Example 1, filtered and defoamed, and then poured into a tank. After transferring and adjusting the temperature to 5℃.

Pour the liquid with a gear pump under pressure of 4Kg/cd to make the pore size QJ.
)7m.

The temperature was controlled at 35°C with a discharge rate of 0.52 from a nozzle with 60 holes, and the yarn was spun into a yarn tow.
Roller pressure was taken off at a speed of rV min. The taken yarn was post-treated in the same manner as in Example 1 to obtain chitin fibers. The yarn was spun for 6 hours, during which time the particles remained good. The obtained chitin fiber had a total denier of 54 d, a single yarn denier of 1.8 d, and a dry strength of 3.242 bar.

The residual elongation was 17.6%. Sixteen of these chitin fibers were taken and braided to create a suture having a thickness of 3-0 according to the Collagen Suture Standard of the US Pharmacopoeia XX Edition.

The tensile strength of the obtained suture was 2.40 to 7. The knot tensile strength is 1.81Kg, which passes the standard (knot tensile strength 1.25Kg or more) and is sufficient for use as a surgical suture6.
It was Ding Noh.

Patent applicant: Unitika Co., Ltd.

Claims (1)

[Claims] (υ When producing chitin fiber by spinning chitin dope consisting of chitin and a solvent, the bath temperature is 10 to 45℃.
A method for producing chitin fibers, characterized by using a coagulation bath of