JP2996773B2 - Manufacturing method of chitin nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a nonwoven fabric comprising chitin fibers. In particular, the present invention relates to a method for producing a chitin nonwoven fabric which can be suitably used as a material for protecting and covering wounds in the medical field.

[0002]

2. Description of the Related Art Chitin, an aminopolysaccharide contained in the exoskeleton of crustaceans, has an aminoacetyl group in each of its constituent units, and therefore has unique properties unlike other polysaccharides. . Therefore, much research has been done using this material. Above all, it has been confirmed that chitin has high biocompatibility, and many attempts have been made to use it as a biomaterial. Among them, as a wound covering protective material, a chitin nonwoven fabric is already marketed under the trade name Vesquitin W (manufactured by Unitika Co., Ltd.). Used in medical facilities. This product has good properties required as a wound covering protective material, such as a high hemostatic effect, a large analgesic effect, and a rapid epidermal formation. As disclosed in Japanese Patent Application Laid-Open No. 61-240963, when producing chitin fibers into a non-woven fabric, water is removed after dispersing chitin short fibers and an adhesive in water, and lamination is performed. It is made by compressing and drying after making the body.

[0003] However, the nonwoven fabric made by such a method has poor flexibility and stretchability. Therefore, for example, when used as a wound covering protective material like Vesquitin W, it has a drawback that it is difficult to use it at a bent portion or in a place where strong external force is applied.

Under such circumstances, an object of the present invention is to provide a method for producing a chitin nonwoven fabric having excellent flexibility and elasticity.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, a chitin nonwoven fabric obtained by using a pressurized water jet has achieved the object. They have found what they can do and have reached the present invention.

That is, the gist of the present invention is a method for producing a chitin nonwoven fabric, which comprises jetting a pressurized water jet onto a short fiber web of chitin fibers. Hereinafter, the present invention will be described in detail.

Chitin is a poly (N-type) obtained by treating an exoskeleton of crustaceans, insects and the like with hydrochloric acid and caustic soda.
Acetyl-D-glucosamine) or this poly (N-acetyl-D-glucosamine) treated with concentrated alkali to obtain a deacetylated product (deacetylation degree of several percent to 10%).
Some values are up to 0%. ), Of which
Those that have a high degree of deacetylation and dissolve in acids are particularly called chitosan.

The chitin referred to in the present invention is such a chitin, deacetylated chitin or chitosan, and furthermore, a chitin or a glucosamine residue of chitosan.
Derivatives in which the OH or —CH ₂ OH group or amino group is esterified, etherified, carboxymethylated, hydroxyethylated or O-ethylated are also included.

The chitin fiber means a fiber obtained by dissolving chitin in a solvent to form a solution. There are basically two ways to make a solution of chitin. Part 1
The first is the case of chitin with a low degree of deacetylation. These solvents include dimethylacetamide or a mixture of N-methylpyrrolidone and lithium chloride, and a mixture of trichloroacetic acid and a halogenated hydrocarbon. . When about 2 to 10% by weight of purified chitin is dissolved in a powder form in these solvents, a viscous and transparent solution can be produced.

[0010] As a general method for producing fibers from these solutions, a solution contained in a pressurized tank is metered and sent by a gear pump or the like, and a nozzle including a filter, for example,
It can be made by extruding into a liquid such as water or alcohol which is a coagulating liquid from a fine hole of about 0.03 to 0.1 mmφ, coagulating, and taking off at a constant speed. After the resulting fiber is sufficiently dried after removing impurities such as a solvent and a coagulating liquid, chitin fiber is obtained. When used in the present invention, the thickness of each fiber is preferably from 0.2 to 50 denier, more preferably from 0.5 to 10 denier, most preferably from 0.7 to 5 denier.

The deacetylated chitin fibers can be prepared by treating these chitin fibers with a concentrated aqueous sodium hydroxide solution, for example, having a concentration of 10 to 30% by weight, at a temperature of 80 ° C. or higher. The degree of deacetylation can be adjusted by selecting the concentration of caustic soda, the temperature, and the treatment time.

In order to prepare fibers from chitin having a high degree of deacetylation, for example, chitosan, generally, an aqueous solution of acetic acid can be used as a solvent. For example, if acetic acid is
An aqueous acetic acid solution containing about 1 to 5% by weight of chitosan 0.5 to 1
When 0% by weight is dissolved, a clear and viscous solution is formed.
This is put into a pressurized tank as in the case of the chitin solution, measured by a gear pump, and discharged from a fine nozzle. As the coagulating liquid, simple water or alcohol, water or alcohol solution containing alkali, or the like can be used. The coagulated fiber is taken off at a constant speed.
After washing, impurities such as a solvent and a coagulating liquid are sufficiently removed and dried, a chitosan fiber can be obtained. In this case, the size of each fiber is almost the same as that of the chitin fiber. The chitosan fiber can be used as it is, but may be treated in an alcohol containing acetic anhydride to slightly promote acetylation.

The present invention uses a so-called spunlace method of jetting a jet of water onto a web when producing a nonwoven fabric from these chitin fibers.

First, chitin fibers are cut into short fibers.
The length is preferably 0.5 to 10 cm, and more preferably 1 to 6 cm. The cut chitin fibers are loosened one by one with an opening card machine, and a cotton-like material (web) is created with the card machine. Place the web on a coarse wire mesh and hit the high-speed jet from above.
This is to obtain a confounding effect while curling the constituent fibers. By pressing and heating the entangled fiber layer, a nonwoven fabric can be obtained. At this time, the thickness of the non-woven fabric can be adjusted by the thickness of the cotton web opened by the card, and the fiber entanglement can be adjusted by the cut length and the pressure of the water jet discharged from the nozzle. The gap between the fibers of the nonwoven fabric can be adjusted by the roughness of the wire mesh. Details of the above spunlace method are described in, for example, Japanese Patent Publication No. 49-20823.

Preferred conditions for obtaining a chitin nonwoven fabric by the spunlace method are as follows: water jet pressure: 500 to 10,000 psi; nozzle diameter: 0.05 to 0.5 m.
m, the mesh of the wire mesh is 10 to 100 mesh, and the sheet feeding speed is 5 to 20 m / min.

As described above, the chitin nonwoven fabric obtained by the spunlace method has a high degree of entanglement of the fibers, and thus is rich in flexibility and stretchability. For example, when the bending stiffness is measured with a KES-F2 pure bending tester, 0.05 to 0.2 g is obtained.
f · cm ² / cm, which is lower than the value of the bending stiffness of 0.5 to ² gf · cm ² / cm prepared by the papermaking method, and does not break even when bent. Therefore, it can be widely used in industry and can be suitably used as a medical article such as a wound dressing.

[0017]

EXAMPLES The present invention will be described more specifically with reference to the following examples. Example 1 Crude chitin powder (manufactured by Shin Nippon Chemical Co., Ltd.) was treated with 1N hydrochloric acid at 40
C. for 1 hour, and further heat-treated in a 3% aqueous sodium hydroxide solution at 90.degree. C. for 3 hours to remove calcium and protein contained in the crude chitin powder. 7% by weight of this chitin powder was dissolved in a mixed solvent of dimethylacetamide and lithium chloride (weight ratio: 92: 8) to prepare a transparent solution.

This solution was filtered through a 1480 mesh stainless steel net, filled in a tank, fed with a gear pump while pressurizing with compressed air, extruded from a 0.05 mmφ nozzle into hot water at 80 ° C., and solidified. After doing, 10m / mi
After picking up at a speed of n, washing with hot water and drying again, chitin fibers of single denier 0.9 denier were obtained. This was cut to a length of 3 cm.

As the fiber, a nonwoven fabric was manufactured by a spunlace method using a spunlace processing machine (manufactured by Honeycomb). The manufacturing conditions were a water jet pressure of 7800 psi, a wire mesh size of 35 mesh, and a take-up speed of 10 m / min.
, Drying temperature was 150 ° C. The resulting nonwoven fabric has a thickness of 0.15 mm, a strength of 650 g / cm width, and an elongation of 25.
%, Which is a flexible nonwoven fabric with high elongation.

This non-woven fabric was sterilized and used as a protective material for patients suffering from a degree of burn II injuries in the forearm. After the affected area was sterilized and cleaned with Hibiten, the chitin nonwoven fabric of this example was applied to the entire forearm. Place the gauze on the top of it,
Lightly squeezed, secured with skin tape, and covered with a bandage.

Immediately after the application, the pain of the patient was remarkably reduced. Three days later, the chitin nonwoven fabric adhered to the affected area, and the elbow of the refraction area was adhered without detachment. The exudate also migrated to the outer gauze, and the affected area remained moist. When left as it was, the affected area began to dry on the 10th day, the chitin non-woven fabric was detached on the 15th day, and the formation of the epidermis under the material had been completed.

Example 2, Comparative Example 1 Chitosan powder (manufactured by Shin Nippon Chemical, 0.2% in 2% acetic acid aqueous solution)
A solution having a dissolved viscosity of 250 centipoise (B type rotational viscometer, 1000 rpm) was dissolved in a 3% aqueous acetic acid solution at 4% by weight to obtain a viscous and transparent solution. After the solution was filtered through a 1480 mesh stainless steel net, it was put into a pressurized tank, and metered and sent by a gear pump. In addition, 0.08m
After discharging into a 1% aqueous solution of caustic soda from a fine nozzle of mφ to solidify, it was wound up at a speed of 12 m / min. The obtained fiber was sufficiently washed to obtain a chitosan fiber having a denier of about 2.1 denier.

This fiber was cut into a length of 32 mm, and a non-woven fabric was manufactured using a spunlace processing machine (manufactured by Honeycomb) which is an underwater entanglement method. The production conditions were a water jet pressure of 5200 psi, a wire mesh size of 50 mesh, a take-off speed of 15 m / min, and a drying temperature of 135 ° C. The finished nonwoven fabric has a thickness of 0.17 mm and a strength of 51.
It was a flexible, high-strength nonwoven fabric having a width of 8 g / cm and an elongation of 32% (Example 2).

On the other hand, the same chitosan fiber was cut to a length of 5 mm, and 1% of polyvinyl alcohol fiber (SML manufactured by Unitika) was added to 10% and dispersed in water. Then, water was removed, and the laminate was pressed. The nonwoven fabric was manufactured by a drying method, a so-called papermaking method. Non-woven fabric thickness 0.18mm, strength 48
The width was 1 g / cm and the elongation was 5% (Comparative Example 1).

[0025] These chitosan nonwoven fabrics were used as a protective material for a 16-year-old male patient who had been crushed in such a way as to expose bones and tendons to the right ankle in a motorcycle accident. First, the affected part was sterilized and cleaned with povidone-iodine solution, and then protected in Comparative Example 1. Two days later, the affected part was melted and lost its protective action. Next, when the nonwoven fabric of Example 2 was used, on the third day, it did not melt and was in good contact. Furthermore, on the 10th day, granulation was formed in the affected area,
The granulation had formed up to the upper part of the tendons and bones. On the 15th day, when the granulation was sufficiently formed, the skin could be transplanted. In other words, granulation can be formed in deep wounds,
It was useful as a protective material.

[0026]

The chitin nonwoven fabric obtained by the method of the present invention is flexible and has high elasticity, so that it can be used in various fields as a filter cloth or a protective cloth. For example, it can be used as a material for protecting and covering wounds in the medical field, and can provide a high therapeutic effect.

Claims (1)

(57) [Claims] 1. A method for producing a chitin nonwoven fabric, comprising jetting a pressurized water jet onto a short fiber web of chitin fibers.