KR100323253B1 - The chitosan fiber having high degree of strength and elasticity - Google Patents

Abstract

The present invention is cross-linked by using an acidic solution containing sodium sulfate, sulfuric acid, a compound selected from the group consisting of glutaaldehyde, epichlorohydrin, or a mixture thereof to a fibrous polymer material having a crosslinking capability such as chitosan By forming chemical bonds between polymer chains, the present invention relates to chitosan fibers which have high strength and high elasticity, as well as form stability in water or alkali.

Description

Chitosan fiber with high strength and high elasticity {THE CHITOSAN FIBER HAVING HIGH DEGREE OF STRENGTH AND ELASTICITY}

[TECHNICAL FIELD OF THE INVENTION]

The present invention relates to chitosan fibers having high strength and high elasticity, and more particularly, selected from the group consisting of glutaaldehyde, epichlorohydrin, or a mixture thereof in a fiber-forming polymer material having a crosslinking ability such as chitosan. By crosslinking with an acidic solution containing a compound, sodium sulfate, sulfuric acid to form a chemical bond between the polymer chains, the present invention relates to chitosan fibers having high strength, high elasticity, and morphological stability in water or alkali.

[Private Technology]

The most important factors involved in the quality of nonwovens or paper are determined by the hydrogen bonds between the hydroxyl groups and the amino term between the fibers. In order to increase the strength of the nonwoven fabric or paper, hydrogen bonding force must be increased, and a method of increasing the contact point between fibers by beating fiber and pulp is generally adopted. Recently, the strength enhancer, which is a water-soluble polymer, has been used. When the paper is dried with the addition of the strength enhancer, the strength enhancer gathers at the fiber contact due to capillary action, and adhesion occurs. Cellulose, which has formed the mainstream of paper or non-woven fabrics until now, is dispersed in water to show anions by oxidizing groups such as hydroxyl groups and trace amounts of carboxyl groups. However, the strength and elasticity of the nonwoven fabric or paper made of hydrogen bonds have a certain limit no matter how high the strength of hydrogen bonds.

On the other hand, chitosan, which has been spotlighted as a biopolymer in recent years, is insoluble in water but dissolved in dilute acid and becomes cationic. Is dragging. Until recently, chitin or chitosan alone has been reported to be difficult to manufacture paper or nonwoven fabric, and it has been reported that it can be produced by using a binder. However, if chitin is mechanically treated as a pulp, it becomes a papermaking raw material.

When flake chitin is dissociated in water in a mixer or the like, it becomes a colloidal dispersion. In Japanese Patent Application Laid-Open No. 56-68200, there is a report in which this chitin dispersion is made alone. However, not only the sheet stability and the like, but also lack of form stability, the elasticity and strength does not meet the expectations.

In addition, US Pat. No. 4,392,916 increases the hydrogen bonding power of chitin to make a fiber consisting of chitin only. The fiber is mainly used for medical treatment because it is less harmful to the human body. However, the fiber also does not meet the expectations in terms of elasticity and strength as it was intended to increase the hydrogen bonding force between chitin molecules, and lacks form safety against water or alkali.

Accordingly, an object of the present invention is to provide a chitosan fiber manufacturing method for producing chitosan fiber having high strength, high elasticity and excellent form safety against water or alkali, and to provide chitosan fiber according to the above production method. It is another object of the present invention to provide a chitosan nonwoven fabric manufacturing method of chitosan nonwoven fabric having high strength, high elasticity and excellent form safety against water or alkali, and to provide a chitosan nonwoven fabric produced by the chitosan nonwoven fabric manufacturing method. .

1 is a molecular structure of cellulose, chitin and chitosan,

2 is a cross-linking mechanism of glutaaldehyde between chitosan polymer chains,

Figure 3 shows the cross-linking mechanism of epichlorohydrin between chitosan polymer chains.

[Means for solving the problem]

In order to achieve the above object, the present invention comprises a) a pretreatment step of a polymer raw material which removes inorganic salts and proteins from a material containing chitin and deacetates; b) a spinning stock solution dissolving the pretreated material in a weakly acidic solution. C) spinning process of spinning the prepared spinning stock solution; d) coagulation process of solidifying the spun fiber; e) flush washing process of washing and stretching with water to deoxidize or de-alkaline the solidified fiber. ; And f) 0.01 to 3.5% by weight of a compound selected from the group consisting of: flush-stretched fibres) glutaaldehyde, epichlorohydrin, or mixtures thereof; ii) 10 to 30% by weight sodium sulfate; And iii) a crosslinking treatment step of crosslinking using an acidic solution containing 0.1 to 3% by weight of sulfuric acid.

In another aspect, the present invention provides a chitosan fiber produced by the above production method.

In another aspect, the present invention is a) a pre-treatment step of the polymer raw material to remove inorganic salts and proteins from the chitin-containing material, deacetate; b) a step of preparing a spinning stock solution dissolving the pre-treated material in a weakly acidic solution; c) A spinning step of spinning the prepared spinning stock solution; d) a coagulation step of solidifying the spun fiber; e) a flush stretching step of washing and stretching with water to deoxidize or de-alkaline the coagulated fiber; f) flush washing Iii) 0.01 to 3.5% by weight of a compound selected from the group consisting of glutaaldehyde, epichlorohydrin, or mixtures thereof; ii) 10 to 30% by weight of sodium sulfate; And iii) crosslinking process using an acidic solution containing 0.1 to 3% by weight of sulfuric acid.

g) a molding process of molding the crosslinked liquid treated chitosan fibers; And

h) dry crosslinking treatment process for dry crosslinking the molded material;

It provides a chitosan nonwoven manufacturing method consisting of.

In another aspect, the present invention provides a chitosan nonwoven fabric produced by the chitosan nonwoven fabric manufacturing method.

Hereinafter, the present invention will be described in detail.

Mechanism of action of crosslinking agent

Structural formulas of cellulose, which occupy most of the fiber-forming polymers, and structural formulas of chitin and chitosan, which are in the spotlight in recent years, are represented by (A), (B), and (C) in FIG. Chitin is a nitrogen-containing polysaccharide, which is an important component of the skin of arthropods, the shell of mollusks, or the cell membranes of fungi, and exists as a glycoprotein in vivo. Chitosan molecules are the product of deacetylation of chitin molecules.

Hydrogen bonds, which influence the strength and elasticity of a fiber product including a conventional general nonwoven fabric, occur between carbon 6 of one molecule and molecules 2 or 3 of another molecule in FIG. 1. Conventional intensifiers were intended to increase strength or elasticity by increasing the force of hydrogen bonding.

However, in the present invention, glutaaldehyde or epichlorohydrin replaces the hydrogen bond with a complete chemical bond to increase the strength of the bond.

The mechanism in which glutaaldehyde acts as a crosslinking agent is shown in FIG. 2, and the mechanism in which epichlorohydrin acts as a crosslinking agent is shown in FIG. 3. Glutaaldehyde or epichlorohydrin chemically bonds with the OH group of one polymer chain and the OH group or NH ₂ group of the other polymer chain. Sometimes binding occurs within the polymer chain itself.

As described above, as the bond between the fiber-forming polymers is changed from hydrogen bonds to complete chemical bonds, the strength of the bonds between the fiber-forming polymers increases, so that the fiber products including the nonwoven fabric produced by the present invention increase strength and elasticity. .

Preparation of Chitosan Fiber

The preparation of chitosan fibers introduced in the present invention is carried out through the 'pretreatment process of polymer raw material-manufacturing process of spinning stock solution-spinning process-coagulation process-flush stretching process-crosslinking process'.

[Pretreatment of Polymer Resources]

The pretreatment process of the polymer raw material is to improve the dissolving power of the raw material and also to modify the polymer. Substances containing chitin, such as shrimp and crabs, are treated with an acidic aqueous solution to remove inorganic salts containing potassium carbonate. In the acidic aqueous solution, the acid is preferably an inorganic acid, more preferably hydrochloric acid. The acid content in the acidic aqueous solution is preferably in a concentration of 1 to 10% by weight, more preferably 3 to 5% by weight. When the acid content in the acidic solution is less than 1% by weight, the removal of inorganic salts is weak, and when it exceeds 10% by weight, hydrolysis of chitin tissue occurs.

Chitin from which the inorganic salt is removed is treated with an aqueous solution of caustic soda to remove protein. The caustic soda content of the caustic soda solution is preferably 1 to 10% by weight of caustic soda. If the caustic soda content is less than 1 wt% in the aqueous solution of caustic soda, the removal of the protein is insignificant and 10 wt% is sufficient.

The chitin from which the protein was removed was treated with 30 to 60% by weight of an aqueous solution of caustic soda to remove the acetate group (-COCH3) in the chitin molecule. If the concentration of the aqueous solution of caustic soda is less than 30% by weight deacetization is not performed well, if it exceeds 60% by weight chitin molecules are hydrolyzed. Deacetization followed by washing with water yields a dry chitosan flake having a deacetization degree of at least 95%.

[Manufacturing process of spinning solution]

The chitosan flakes are dissolved in acidic aqueous solution. The content in the solution of chitosan flakes is preferably from 1 to 10% by weight. If the content of the chitosan plate is less than 1% by weight, the spinning solution is too dilute, and if more than 10% by weight, the viscosity rises and spinning is not performed. The acid in the acidic aqueous solution is preferably an organic acid, more preferably acetic acid. In addition, the concentration of the acidic aqueous solution preferably contains 1 to 10% by weight of acid. When the concentration of the acidic aqueous solution is less than 1% by weight, the solubility of the chitosan flakes is lowered, and at 10% by weight or more, hydrolysis of chitosan occurs.

[Spinning process]

It spins to solidify the spinning stock solution. Common spinning methods are used and include dry spinning, wet spinning and dry-wet spinning.

[Solidification process]

As a step of solidifying the spun chitosan, a general solidification method is used. Preferably, 1 to 10% by weight caustic soda is preferably coagulated in a mixed solution dissolved in 30 to 40 v / v% alcohol aqueous solution.

[Flush Stretching Process]

The solidified fiber is washed with water. This is to deoxidize and dealkaline chitosan. The washed chitosan fiber is stretched in boiling water to obtain a stretched fiber. The temperature of boiling water depends on the draw ratio. Preferably 95 to 100 degreeC is preferable. If the temperature is less than 95 ° C., the stretching may not be performed well, and water may not exceed 100 ° C., and if it exceeds 100 ° C., steam drawing is required.

[Crosslinking Process]

A) 0.01 to 3.5% by weight of a compound selected from the group consisting of glutaaldehyde, epichlorohydrin, or a mixture thereof; b) 10 to 30% by weight of sodium sulfate; And c) crosslinking at 30 to 70 v / v% of an aqueous alcohol solution containing 0.1 to 3% by weight of sulfuric acid.

Glutaaldehyde and the like is for the purpose of crosslinking the fiber chains of the stretched fiber, if the content of glutaaldehyde and the like in the cross-linking solution is less than 0.01% by weight crosslinking does not occur, when the excess of more than 3.5% by weight of the remaining hydroxide Since there is no practical skill, glutaaldehyde and the like become useless. Preferably it is 0.05 to 1 weight% further.

Sulfuric acid serves as a catalyst for the crosslinking reaction. If the content of sulfuric acid in the crosslinking solution is less than 0.1% by weight, the catalysis is weak and if the content is more than 3% by weight, a large amount of buffer is required and economic efficiency is low. Preferably it is more preferable if it is 0.3 to 1.0 weight%.

Sodium sulfate acts as a buffer for sulfuric acid in the mixed solution. If the content of sodium sulfate in the cross-linking solution is less than 10% by weight does not serve as a buffer, when the content exceeds 30% by weight is economical.

In addition, the crosslinking treatment process may be used by mixing a strength enhancer, a sizing press, a surfactant, or a retention enhancer with glutaraldehyde and the like.

Conventional fiber manufacturing methods have used a process of preparing stretched fibers in a solidification process, drying the stretched fibers, cutting the dried fibers, and dispersing the cut fibers in a dispersion medium containing a binder or the like. However, the present invention can also shorten the process by cross-linking the stretched fiber without the drying process.

The cut fibers (staple fibers) treated with the crosslinking solution are dispersed using a stirrer according to the general method of manufacturing the nonwoven fabric. The dispersed fibers are simultaneously formed into a crosslink and a nonwoven fabric by a drying process of the nonwoven fabric manufacturing process. On the other hand, the fiber in the tow state is crosslinked and dried in the subsequent drying step after being immersed in the crosslinking liquid to become crosslinked tow fiber.

Manufacture of Nonwovens

The nonwoven fabric is manufactured through a 'molding process-a drying process' after the crosslinking process in the fiber manufacturing process.

[Molding process]

In the production of the fibers, the dispersed fiber solution during the crosslinking treatment step is poured into a mold which can be adjusted in thickness to adjust its thickness and shape. The shape of the nonwoven fabric or paper can be any shape such as plate or cone shape.

[Drying process]

The fiber poured into the mold is dried using a general drying method such as freeze drying, vacuum drying, natural drying or hot air drying. If the surface of the mold for manufacturing non-woven fabric or paper is made of stainless steel of 400 mesh or less, it may not be subjected to a separate de-methanol process and may be used again as a dispersion medium.

EXAMPLE

Hereinafter, the Example and comparative example of this invention are described. However, the following examples are intended to illustrate the invention and not to limit the invention.

Example 1

5 kg of crab shells were collected and treated with 5% aqueous hydrochloric acid solution, and then the shrimp shells treated with the aqueous hydrochloric acid solution were treated with 5% by weight caustic soda, and then 50% by weight caustic shrimp shell was treated with caustic soda. It was immersed in a soda bath for 3 hours and dried to obtain 4.2 kg of dry chitosan flakes.

Example 2

The dried chitosan flakes of Example 1 were dissolved in 5 wt% acetic acid solution so that the content ratio was 5 parts: 95 parts, respectively. The solution in which the chitosan flakes were dissolved was extruded at a rate of 10 m / min into a platinum-gold alloy nozzle (0.1 mm φ × 300 holes) at room temperature. The extruded chitosan fibers were placed in a mixed solution of 5 wt% caustic soda dissolved in 40 v / v% aqueous solution of methanol.

Example 3

Chitosan was extruded from the mixed aqueous solution of Example 2 at a rate of 10 m / min. Subsequently, the extruded chitosan fibers were subjected to coagulation washing treatment in a coagulation bath composed of water, and the washed chitosan fibers were drawn 1.3 times in a boiling water bath composed of water maintaining a temperature of 98 ° C. to obtain 500 g of stretched fibers. The dry fineness was 2.15 deniers.

Example 4

The stretched fiber obtained in Example 3 was crosslinked in a 50 v / v% methanol aqueous solution containing 20% sodium sulfate, 0.5% sulfuric acid, and 0.1% glutaraldehyde. The cross-linked fibers were cut by 7 mm and dispersed using a stirrer, followed by hot air drying with steam at 120 ° C. to obtain 100 g of cross-linked tow fibers.

Example 5

After cutting the stretched chitosan fibers obtained in Example 3 by 7 mm and dispersed in the crosslinking solution of Example 4, the dispersed chitosan fibers were poured into a plate-shaped mold and hot-air dried at 120 ° C. for 5 hours to form a plate. And 100 g of a nonwoven fabric having a thickness of 0.320 mm was obtained.

Example 6

The stretched fiber obtained in Example 3 was replaced with 0.1 wt% epichlorohydrin in place of 0.1 wt% glutaaldehyde in Example 4, and was treated in the same manner as in Example 4 to obtain 100 g of crosslinked tow state. Fiber was obtained. In addition, the stretched tow fiber was treated in the same manner as in Example 5 to obtain 100 g of a nonwoven fabric having a plate shape and a thickness of 0.319 mm.

Comparative Example 1

Strength, elasticity and elongation of the stretched fiber obtained in Example 3 and the crosslinked fiber obtained in Example 4 and Example 6 were compared. The measuring method was made according to the general method of measuring strength, elasticity or elongation, and the results are shown in Table 1 below.

Analytical Sample Strength (grams / denier) Elasticity (gram / denier) Elongation (%) Example 3 2.11 60 10.43 Example 4 2.50 100 9.50 Example 6 2.49 99 9.52

As shown in Table 1, it can be seen that the strength, elasticity, and elongation are all improved when the stretched fiber is treated with glutaaldehyde or epichlorohydrin.

Comparative Example 2

In order to test the morphological stability effect of the crosslinked nonwoven fabric of the present invention, the non-crosslinked nonwoven fabric prepared by the nonwoven fabric of Example 3, the nonwoven fabric of Example 5, the nonwoven fabric of Example 5, The nonwoven fabrics of Example 6 were subjected to comparative tests for morphological safety of water.

In the experimental method, the test materials were cut into 100 mm x 100 mm in width and length, and immersed in water at 25 ° C. for 2 hours, and then the degree of swelling of the nonwoven fabric before and after immersion was examined. The results are shown in Table 2 below.

Test subject Survey Before swelling After swelling Non-crosslinked Nonwovens Thickness (mm) 0.311 0.348 Width (mm × mm) 100 × 100 105 × 104.5 Nonwoven Fabric of Example 5 Thickness (mm) 0.320 0.325 Width (mm × mm) 100 × 100 100.5 × 100 Nonwoven Fabric of Example 6 Thickness (mm) 0.319 0.325 Width (mm × mm) 100 × 100 100.6 × 100.1

As shown in Table 2, it can be seen that the nonwoven fabric of Example 5 or the nonwoven fabric of Example 6, which is a crosslinked nonwoven fabric, is superior in shape safety to water as compared to the nonwoven fabric that is not crosslinked.

As described above, the chitosan fibers of the present invention increase the strength of the bonds by replacing the hydrogen bonds between the chitosan chains with chemical bonds, and thus, the chitosan fibers have superior strength and elasticity as compared to the conventional chitosan fibers. It can be seen that the nonwoven fabric is superior in strength and elasticity as compared with the conventional chitosan nonwoven fabric.

Claims (6)

a) removing inorganic salts and proteins from the material containing chitin, and deacetate A pretreatment step of polymerizing the raw material; b) preparing a spinning stock solution in which the pretreated material is dissolved in a weakly acidic solution; c) spinning process for spinning the prepared spinning stock solution; d) a solidification process for solidifying the spun fibers; e) washed with water and softened to deoxidize or de-alkaline the coagulated fibers; Shinha flush washing process; And f) the flush-drawn fibers Iii) consisting of glutaaldehyde, epichlorohydrin, or mixtures thereof 0.01 to 3.5% by weight of a compound selected from the group; Ii) 10 to 30% by weight sodium sulfate; And Viii) 0.1 to 3 wt% sulfuric acid Crosslinking process for crosslinking using an acidic solution comprising a Method for producing chitosan fiber consisting of. delete A chitosan fiber produced according to claim 1. a) removing inorganic salts and proteins from the material containing chitin, and deacetate A pretreatment step of polymerizing the raw material; b) preparing a spinning stock solution in which the pretreated material is dissolved in a weakly acidic solution; c) spinning process for spinning the prepared spinning stock solution; d) a solidification process for solidifying the spun fibers; e) washed with water and softened to deoxidize or de-alkaline the coagulated fibers; Shinha flush washing process; f) the flush-drawn fibers Iii) consisting of glutaaldehyde, epichlorohydrin, or mixtures thereof 0.01 to 3.5% by weight of a compound selected from the group; Ii) 10 to 30% by weight sodium sulfate; And Viii) 0.1 to 3 wt% sulfuric acid Crosslinking process for crosslinking using an acidic solution comprising a g) a molding process of molding the crosslinked liquid treated chitosan fibers; And h) a dry crosslinking treatment step of dry crosslinking the molded material; Chitosan non-woven fabric manufacturing method consisting of. delete A chitosan nonwoven fabric prepared according to claim 4 or 5.