JP2754162B2 - Manufacturing method of chitin sponge, chitin paper and chitin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing chitin sponge, chitin paper, and chitin film as a chitin molded product. Since it has properties such as degradability, it can be preferably used in a wide range of fields such as biomaterials, medical materials, agricultural materials, animal feed, and other industrial materials.

[0002]

2. Description of the Related Art Chitin is a natural polysaccharide in which N-acetyl-D-glucosamine is linked by 1,4-.beta., And is used for crustaceans such as crabs and shrimps, insect shells such as beetles and grasshoppers, and fungi. It is a polysaccharide that exists in natural organisms such as cell walls, and is a valuable resource with abundance comparable to cellulose. Chitin has an acetamido group in the molecule, and because of the strong hydrogen bond between the acetamido group and the hydroxyl group, it has high chemical resistance and is hardly soluble in organic solvents. For this reason, as a solvent for dissolving chitin, many more solvents have been disclosed. That is, polyhalogenated hydrocarbon-halogenated carboxylic acid such as hexafluoroacetone, hexafluoroisopropanol, formic acid-dichloroacetic acid type, dimethylcetamide-lithium type, trichloroacetic acid-chlorinated hydrocarbon type (Japanese Patent Application Laid-Open No. 63-117002). No.), N-methylpyrrolidone-lithium system (JP-A-58-134101)
No.) has been proposed. With these conventional solvents,
When the degree of deacetylation is 30% or less, it is difficult to dissolve, and in order to measure the dissolution, it is necessary to repeat the operation of freezing and raising the temperature to dissolve, and there is a disadvantage that the molecular weight is reduced.
Further, conventional solvents are difficult to handle from the viewpoint of safety and hygiene, and there is a high risk of causing harm to the handler due to inhalation or contact.
Applicants have addressed this by providing a degree of deacetylation of 30.
% Or less, and a solvent that is easily dissolved and safe to handle is examined.
No. 5 was filed.

Conventionally known chitin sponges include:
"Proceedings of the First International Conference on Chitin / Chitosan
e on Chitin / Chitosan) on page 300, as "D. chitin sponges", sodium sulfate was mixed with chitin viscose obtained by a method according to cellulose viscose, and the mixture was coagulated in water. A method is described in which sodium sulfate is eluted simultaneously with regeneration to obtain a chitin sponge. Also, JP-A-63-18670
No. 1 discloses chitin dissolved in a mixture of trichloroacetic acid and a halogenated hydrocarbon, a mixture of lithium chloride and N-methylpyrrolidone, and a water-soluble polymer is added to the solution.
There is disclosed a method of obtaining a chitin sponge by coagulating and regenerating in water, an alcohol solution, a ketone solution, or an alkaline solution thereof, simultaneously eluting a water-soluble polymer substance, and then freeze-drying.

Conventionally known chitin paper is disclosed in JP-A-60-231900, in which chitin and its derivatives are dissolved in formic acid, trichloroacetic acid or the like, and the solution is extruded into a coagulation bath through a spinning nozzle. A method is disclosed in which the staple fibers are formed into a shape, cut, and the short fibers are dispersed in water to make paper. Also, Japanese Patent Publication No. 4-6384 discloses that a β-chitin such as squid shell chitin is suspended in water and vigorously stirred or subjected to freezing / thawing to form a gel, which is dispersed in water to make paper. A method for doing so is disclosed.

[0005] Conventionally known chitin films include:
U.S. Pat. No. 2,168,374 discloses a method for preparing a chitin film by preparing chitin into chitin xanthate and then coagulating and regenerating in a sulfuric acid acid bath.
JP-A-145813 discloses that after dissolving chitin in a mixed solvent of trichloroacetic acid and methylene chloride, it is spun from a T-die into a coagulation bath for organic ketones, chlorinated hydrocarbons, alcohols, amides, etc. to regenerate coagulation. A method for obtaining a chitin film has been disclosed.

[0006]

DISCLOSURE OF THE INVENTION The present invention has the disadvantages of the solvents disclosed in the prior art which dissolve chitin, that is, these solvents are difficult to dissolve at a degree of deacetylation of about 30% or less, and have a low reactivity. Because of its high molecular weight, molecular chain cleavage and deacetylation are likely to occur, so that the raw material chitin and the degree of deacetylation and high purity chitin sponge without change in molecular weight, chitin paper,
It has solved the drawbacks such as difficulty in obtaining a chitin film. Further, a complicated process of obtaining a chitin molded body after obtaining chitin viscose is not required,
The step of fibrillating chitin can be omitted, and the danger in handling is solved because a safe solvent is used.

[0007]

SUMMARY OF THE INVENTION The present invention provides a chitin solution obtained by dissolving chitin in a mixed solvent obtained by adding a calcium halide salt or a magnesium halide salt to an alcohol composed of methyl alcohol or ethyl alcohol. A coagulation product is obtained by coagulation and regeneration in a coagulation liquid alone or a mixture of water, ethylene glycol, aqueous citric acid solution and aqueous sodium ethylenediaminetetraacetate solution, and then the coagulation product is freeze-dried to obtain a chitin sponge. A production method and a chitin solution in which chitin is dissolved in a mixed solvent obtained by adding a calcium halide salt or a magnesium halide salt to an alcohol composed of methyl alcohol or ethyl alcohol to obtain a chitin solution, and dissolving the solution in water, ethylene glycol, citric acid aqueous solution, Single use of aqueous solution of sodium ethylenediaminetetraacetate Ku is a coagulation liquid mixing these,
A method for producing chitin paper obtained by dispersing the coagulated product in water after coagulation and regeneration, and papermaking, and a mixed solvent in which chitin is added to an alcohol composed of methyl alcohol or ethyl alcohol and a calcium halide salt or a magnesium halide salt is added. To obtain a chitin solution dissolved in water,
This is a method for producing a chitin film obtained by coagulating and regenerating a film in a coagulation liquid alone or a mixture of ethylene glycol, aqueous citric acid, and aqueous sodium ethylenediaminetetraacetate alone, and then drying.

The chitin used in the present invention may be α-chitin derived from crab shells and shrimp shells or β-chitin derived from squid shellfish, and chitosan obtained by deacetylating chitin may be acetylated in an atmosphere of acetic anhydride. Acetylated chitin and acetylated chitosan having a degree of deacetylation of 30% or less obtained by the conversion can also be used, and the molecular weight of chitin is not particularly limited, and can be completely dissolved in the solvent of the present invention which dissolves chitin. Selected by range.

The alcohol used as a mixed solvent for dissolving chitin is preferably methyl alcohol or ethyl alcohol, and other alcohols are not suitable. The calcium salt or magnesium salt used in combination is a halide, and preferably the calcium salt is calcium chloride.
Dihydrate, calcium bromide dihydrate, calcium iodide
Dihydrate is magnesium chloride.
Hexahydrate is used. The mixed solvent used in the present invention is preferably in a saturated state.

The chitin content of a chitin solution obtained by stirring and dissolving chitin in the above-mentioned mixed solvent at room temperature may be changed depending on the molecular weight of chitin, but the concentration ranges from 0.1 to 10% (% by weight). It can be determined appropriately. When obtaining a chitin sponge, a pore controlling agent or a third component for imparting a softening effect is further added to the chitin solution, and a third component such as a pigment for obtaining chitin paper or a chitin film is used in accordance with the intended use. May be added.

The coagulation solution used in the present invention is a solution of water, an aqueous solution of ethylene glycol, citric acid, or an aqueous solution of sodium ethylenediaminetetraacetate (hereinafter referred to as sodium EDTA) alone or a mixture thereof.

In order to obtain a chitin sponge, the above-mentioned chitin solution is added to a coagulation bath to coagulate and regenerate the chitin, and the coagulated product is sufficiently washed with water and freeze-dried to develop pores. A sponge is obtained, and the chitin paper is obtained by stirring and dispersing the above-obtained coagulated product in water, dehydrating and drying according to a normal papermaking method. In this case, chitin has a self-adhesive property. Since it is not necessary to add a binder material as a third component such as polyvinyl alcohol used in the case of ordinary papermaking, there is no problem at all for medical use. The chitin film is obtained by coagulating and regenerating the above-mentioned chitin solution in the form of a film in the above-mentioned coagulation bath, sufficiently washing with water, and then drying. For wet molding from a chitin solution, a general method of extruding a film from a T-die or the like into a coagulation bath is employed.

[0013]

Hereinafter, the present invention will be described in detail with reference to Examples.
The present invention is not limited to this range. The pore size, degree of deacetylation of chitin, molecular weight of chitin and tensile strength were determined by the following methods.

Pore size The sample was observed with a scanning electron microscope to determine the pore size.

The deacetylation degree sample chitin was finely ground (200 mesh or less), mixed with KBr powder, from the absorbance and 3450 cm ^-1 in 1655 cm ^-1 in FT-IR spectrophotometer, was estimated by the following equation.

[0016]

(Equation 1)

The molecular weight of chitin A sample was dissolved in a mixed saturated solvent of calcium chloride and methyl alcohol, the reduced viscosity was calculated using an Ubbelohde viscometer, and the molecular weight was calculated from the following equation.

[0018]

(Equation 2)

Tensile Strength of Chitin Paper and Chitin Chitin Film A sample was sampled in a size of 10 mm × 20 mm, and the sample was mounted on Tensilon and pulled at a speed of 100 mm / min. I asked.

Example 1 About 400 g of calcium chloride dihydrate was added to 400 ml of methyl alcohol, and the mixture was heated under reflux for about 3 hours. After the solution was cooled to room temperature, insolubles were removed by filtration to obtain a saturated mixed solvent of calcium chloride and methyl alcohol. Chitin from red snow crab (80mesh p
ass, degree of deacetylation 13.0%, molecular weight 350,000
0) 3.0 g was added to the above-mentioned mixed solvent (300 ml), and the mixture was stirred and dissolved at room temperature, and the insoluble matter was removed by filtration to obtain a clear and viscous chitin solution. The obtained chitin solution is 10 cm × 10 c
After casting on a 1.5 mm thick glass plate, the glass plate was immersed in water for 1 hour to solidify and regenerate.
It was peeled off from the glass plate and washed thoroughly with water. The chitin regenerated product was rapidly frozen in liquid nitrogen and vacuum dried at room temperature to obtain a chitin sponge. The thickness of the obtained chitin sponge was 1.2 mm, the average pore diameter was 0.25 μm,
The degree of deacetylation of chitin of the sponge was 12.9%, the molecular weight was 350,000, and there was almost no change from the raw material.

Example 2 The chitin solution obtained in the same manner as in Example 1 was placed on a glass plate of 10 cm × 10 cm for 1.0 cm.
After casting with a thickness of mm, the glass plate was immersed in a mixed solution of a 5% aqueous sodium citrate solution and ethylene glycol (mixing ratio 1/1) for 1 hour to solidify and regenerate. It was peeled off from the glass plate and washed thoroughly with water. The chitin regenerated product was rapidly frozen in liquid nitrogen and vacuum dried at room temperature to obtain a chitin sponge. The thickness of the obtained chitin sponge was 0.8 mm, the average pore diameter was 0.25 μm, and the degree of deacetylation of chitin in the sponge was 13.0%.
The molecular weight was 350,000, almost unchanged from the raw material.

Example 3 A saturated mixed solvent of calcium chloride and methanol, obtained in the same manner as in Example 1, was 300 m
l is chitosan (molecular weight 20,000, deacetylation degree 8
0%) of regenerated chitin (molecular weight 2)
(1,000, 5% deacetylation degree) was dissolved to obtain a clear and viscous chitin solution. The chitin solution is 10cm ×
After casting on a 10cm glass plate with a thickness of 1.5mm,
It was immersed in a 5% sodium EDTA aqueous solution for 1 hour, peeled from the glass, washed sufficiently with water, gradually frozen in a freeze dryer (−35 ° C./2 hours), and vacuum dried to obtain a chitin sponge. The thickness of the obtained chitin sponge is 1.2 mm,
The average pore size was 0.2 μm, the degree of deacetylation of chitin in the sponge was 4.9%, and the molecular weight was 20,000.

Example 4 About 400 g of calcium bromide dihydrate was added to 400 ml of ethyl alcohol, and the mixture was heated under reflux for about 3 hours. After the solution was cooled to room temperature, insolubles were removed by filtration to obtain a saturated mixed solvent of calcium bromide and ethyl alcohol. 1.50 chitin from red snow crab
g (80 mesh pass, deacetylation degree 13%, molecular weight 35
000) was dissolved in 300 ml of the above mixed solvent, and the insolubles were removed by filtration to obtain a clear and viscous chitin solution. The chitin solution was placed on a 10 cm × 10 cm glass plate by 1.0 mm.
And then gently immerse in 5% citric acid solution.
Soaked for hours. The resulting coagulated and regenerated product was peeled off from the glass plate, sufficiently washed with water, and lyophilized under the same conditions as in Example 2 to obtain a chitin sponge. The thickness of the chitin sponge was 0.6 mm, the average pore diameter was 0.5 μm, the degree of deacetylation of chitin of the sponge was 13.2%, the molecular weight was 350,
In both cases, there was almost no change from the raw material.

Example 5 A chitin solution obtained in the same manner as in Example 4 was placed on a glass plate of 10 cm × 10 cm in an amount of 1.0 cm.
After casting with a thickness of mm, the glass plate was immersed in a 10% aqueous ethylene glycol solution for 1 hour to solidify and regenerate. The coagulated and regenerated product was peeled off from the glass plate, washed sufficiently with water, and freeze-dried to obtain a chitin sponge. The resulting chitin sponge has a thickness of 0.7 mm and an average pore diameter of 0.4.
μm, the degree of deacetylation of chitin in sponge is 13.0
% And the molecular weight were 340,000, and there was almost no change from the raw materials.

Comparative Example 1 3 g of chitin used in Example 1
Was dissolved in 100 ml of a mixed solvent of trichloroacetic acid and methylene chloride (mixing ratio: 1/1) at 5 ° C. with stirring to obtain a chitin solution. The chitin solution was cast on a glass plate in the same manner as in Example 1, and immersed in ethanol for 1 hour to coagulate and regenerate. The coagulated and regenerated product was peeled off from the glass plate, sufficiently washed with water, and lyophilized in the same manner as in Example 1 to obtain a chitin sponge. The thickness of the obtained chitin sponge is 1.5m
m, the pore diameter was 0.2 μm on average, the degree of deacetylation of chitin in the sponge was 23.0%, and the molecular weight was 150,000, the degree of deacetylation was high, and the molecular weight was significantly reduced.

Example 6 A transparent and viscous chitin solution was obtained in the same manner as in Example 1. 100 ml of the chitin solution was gently poured into 500 ml of water under stirring to coagulate and regenerate. The resulting precipitate is collected by filtration, sufficiently washed with water, and then 200 ml.
In water. The dispersion was poured into a filter provided with filter paper and suction-filtered. After removing excess water, remove
After drying overnight, a chitin paper was obtained. The basis weight of the obtained chitin paper was 58.3 g / m ² and the tensile strength was 1.75 g. The degree of deacetylation of chitin in chitin paper is 13.
At 3% and the molecular weight was 340,000, there was almost no change from the starting material.

Example 7 100 ml of the chitin solution obtained in the same manner as in Example 6 was gently poured into 500 ml of a 5% aqueous solution of sodium EDTA under stirring to coagulate and regenerate, and the resulting precipitate was collected by filtration. After thoroughly washing the precipitate with water,
Dispersed in ml of water. The dispersion was poured into a filter provided with filter paper and suction-filtered. After removing excess water, it was dried overnight at room temperature to obtain chitin paper. The basis weight of the obtained chitin paper was 60.3 g / m ² and the tensile strength was 1.55 g. The degree of deacetylation of chitin in chitin paper is 1
The molecular weight was 3.0% and the molecular weight was 340,000.

Example 8 A mixed solvent of calcium chloride and methyl alcohol 3 obtained in the same manner as in Example 6
30 g of regenerated chitin (molecular weight: 21,000, deacetylation degree: 5%) obtained by acetylating chitosan (molecular weight: 20,000, deacetylation degree: 80%) is dissolved in 00 ml, and a clear and viscous chitin solution is prepared. Obtained. 5% of the chitin solution
Pour gently into the aqueous sodium EDTA solution with stirring,
The resulting precipitate was collected by filtration. After sufficiently washing the precipitate with water, the precipitate was collected by filtration with a filter paper and dried at 50 ° C. for 5 hours to obtain a chitin paper. The obtained chitin paper had a basis weight of 110.5 g / m ² , a tensile strength of 3.55 g, a degree of deacetylation of chitin of the chitin paper of 4.9%, and a molecular weight of 20,000, which was the same as the raw material.

Example 9 In the same manner as in Example 4, a saturated mixed solvent of calcium bromide and ethyl alcohol was obtained.
3.0 g (80 mesh pass, 13% deacetylation degree, molecular weight 350,000) of chitin derived from red snow crab was dissolved in 300 ml of the above-mentioned mixed solvent, and insoluble materials were removed by filtration to obtain a clear and viscous chitin solution. Was. 50 ml of this solution is 300 m
The mixture was gently poured into 1 l of a 5% citric acid solution under stirring to coagulate and regenerate, and the resulting precipitate was collected by filtration. After sufficiently washing the precipitate with water, the precipitate was collected by filtration on filter paper and dried overnight at room temperature to obtain chitin paper.
The basis weight of the obtained chitin paper was 58.3 g / m ² and the tensile strength was 1.45 g. The chitin paper had a chitin deacetylation degree of 13.2% and a molecular weight of 350,000, which was almost the same as the starting material.

Example 10 50 ml of a chitin solution obtained in the same manner as in Example 8 was poured into 300 ml of a 10% aqueous ethylene glycol solution under stirring to coagulate and regenerate. The resulting precipitate was collected by filtration, thoroughly washed with water, and cooled to room temperature. And dried overnight to obtain chitin paper. The basis weight of the obtained chitin paper is 63.8 g / m ^2.
The tensile strength was 2.65 g. The chitin paper had a chitin deacetylation degree of 13.0% and a molecular weight of 34.
At 000, there was almost no change from the raw material.

<< Comparative Example 2 >> 3 g of chitin used in Example 6
Was dissolved in 100 ml of a mixed solvent of trichloroacetic acid and methylene chloride (mixing ratio 1/1) at 5 ° C. to obtain a chitin solution. The chitin solution was gently poured into 300 ml of ethyl alcohol under stirring to coagulate and regenerate. The resulting precipitate was collected by filtration, sufficiently washed with water, and dried overnight at room temperature to obtain chitin paper. The basis weight of the obtained chitin paper was 58.6 g / m ² , the tensile strength was 0.8 g, and the degree of deacetylation of chitin in the chitin paper was 23.
0%, molecular weight 150,000, low tensile strength,
The degree of deacetylation was increased and the molecular weight was significantly reduced.

Example 11 A transparent and viscous chitin solution was obtained in the same manner as in Example 1. The obtained chitin solution was added to 1
After casting on a glass plate of 0 cm × 10 cm with a thickness of 15 mm, the glass plate was immersed in water for 1 hour to solidify and regenerate. After peeling off from the glass plate and thoroughly washing with water, it was air-dried at room temperature overnight to obtain a chitin film. The thickness of the obtained chitin film was 25 μm, the tensile strength was 1.75 kg, and the degree of chitin deacetylation of the film was 1
2.9%, molecular weight was 350,000, and there was almost no change from the raw material.

Example 12 A chitin solution obtained in the same manner as in Example 11 was placed on a 10 cm × 10 cm glass plate.
After casting at a thickness of 5 mm, the glass plate was immersed in a 5% aqueous solution of sodium citrate and ethylene glycol (mixing ratio: 1/1) for 1 hour to solidify and regenerate. It was peeled off from the glass plate, washed sufficiently with water, and dried with hot air at 50 ° C. for 5 hours to obtain a chitin film. The obtained chitin film has a thickness of 30 μm and a tensile strength of 2.0 k.
g, the degree of deacetylation of chitin in the film is 13.0%,
The molecular weight was 350,000, almost unchanged from the raw material.

Example 13 Chitosan (molecular weight: 20,000, degree of deacetylation: 80%) was acetylated in 300 ml of a saturated mixed solvent of calcium chloride and methyl alcohol obtained in the same manner as in Example 11. 30 g of regenerated chitin (molecular weight 21,000, degree of deacetylation 5%) was dissolved to obtain a clear and viscous chitin solution. The chitin solution was cast on a 10 cm × 10 cm glass plate at a thickness of 15 mm, immersed in a 5% sodium EDTA aqueous solution for 1 hour, peeled from the glass plate, sufficiently washed with water, and dried overnight at room temperature to obtain a chitin film. I got The thickness of the obtained chitin film is 40 μm, the tensile strength is 3.55 kg, the degree of deacetylation of chitin of the film is 4.9%, and the molecular weight is 2
At 000, there was almost no change from the raw material.

Example 14 A clear and viscous chitin solution was obtained in the same manner as in Example 4. 10 cm of this chitin solution
After casting on a × 10 cm glass plate with a thickness of 10 mm, the plate was gently immersed in a 5% citric acid solution for 1 hour to coagulate and regenerate. After peeling off from the glass plate and washing sufficiently with water, it was dried in the same manner as in Example 12 to obtain a chitin film. This chitin film has a thickness of 15 μm and a tensile strength of 1.35.
kg, the chitin deacetylation degree of the film is 13.2
%, The molecular weight was 350,000, and there was almost no change from the raw material.

Example 15 A chitin solution obtained in the same manner as in Example 14 was placed on a 10 cm × 10 cm glass plate.
After casting at a thickness of 5 mm, the glass plate was immersed in a 10% aqueous solution of ethylene glycol for 1 hour to solidify and regenerate. It was peeled off from the glass plate, sufficiently washed with water, and dried overnight at room temperature to obtain a chitin film. The obtained chitin film has a thickness of 35 μm and a tensile strength of 2.0.
4 kg, the chitin deacetylation degree of the film is 13.0
%, Molecular weight was 340,000, and there was almost no change from the raw material.

Comparative Example 3 3 g of chitin used in Example 1
Was dissolved in 100 ml of a mixed solvent of trichloroacetic acid and methylene chloride (mixing ratio 1/1) at 5 ° C. to obtain a chitin solution. The chitin solution was cast on a glass plate in the same manner as in Example 11, and immersed in ethyl alcohol for 1 hour to coagulate and regenerate. After peeling from the glass plate and sufficiently washing with water, the same operation as in Example 11 was performed to obtain a chitin film. The thickness of the obtained chitin film is 25 μm, the tensile strength is 0.8 kg, the degree of deacetylation of chitin of the film is 23.0%, the molecular weight is 150,000, the tensile strength is low, and the degree of deacetylation is high. The molecular weight was remarkably reduced.

[0038]

The method for producing chitin sponge, chitin paper and chitin film of the present invention uses chemicals which are safer and easier to handle than conventional solvents which dissolve chitin during the production. Also, since there is no decrease in the molecular weight of chitin and no increase in the degree of deacetylation upon dissolution, it is possible to obtain an unprecedented high-purity chitin sponge, chitin paper and chitin film. The chitin sponge, chitin paper, and chitin film obtained by the present invention can be prepared by using a harmful solvent such as formic acid, trichloroacetic acid, or dimethylacetamide when dissolving chitin, and using ethyl alcohol or methyl alcohol and salts such as calcium chloride. Since there is only a small amount of chemicals remaining in molded products that pose a problem for safety, there is no danger when used as a medical material in the human body, etc., and low immunogenicity and biocompatibility of chitin And excellent properties such as biodegradability.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // A61L 15/00 A61L 27/00 V 27/00 D21H 5/20 F

Claims (3)

(57) [Claims] 1. A chitin solution is obtained by dissolving chitin in a mixed solvent of an alcohol composed of methyl alcohol or ethyl alcohol, and a calcium halide salt or a magnesium halide salt.
A method for producing a chitin sponge, comprising coagulating and regenerating a coagulated product in a coagulating solution of a citric acid aqueous solution and an aqueous solution of sodium ethylenediaminetetraacetate alone or a mixture thereof to obtain a coagulated product, and freeze-drying the coagulated product. 2. A method for producing chitin paper, comprising dispersing the coagulated product according to claim 1 in water and making paper. 3. The method according to claim 1, wherein the chitin solution according to claim 1 is used.
3. A method for producing a chitin film, comprising coagulating and regenerating a film in the coagulating liquid described in 1) and then drying.