JPH02200810A - Production of pulpy chitosan fiber and production apparatus therefor - Google Patents

Abstract

PURPOSE:To obtain the title fiber branched like beaten cellulose pulp by adding a chitosan solution to a coagulating fluid flowing in the form of two continuous laminar flows from the two directions facing each other. CONSTITUTION:Four rolls 1, 1, 1, 1 set up in two-rows-and-two-columns at approximately equal intervals in a box-type coagulating tank 2 are rotated in the directions shown by four arrows, a coagulating fluid is introduced, in the form of two continuous laminar flows from the two directions facing each other, into the central part of the tank 2, and the respective laminar flows are diverted in the nearly rectangular direction, being discharged externally. A chitosan solution is dripped, through a charge pipe 4, to the central part of the tank 2, being coagulated while drawn left and right, thus obtaining the objective branched chitosan fiber >=1mm in length.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel method and apparatus for producing chitosan fibers as a raw material for special papers such as separation membranes, medical materials, and food wrapping paper. More specifically, the present invention relates to a simple method for producing chitosan fibers in the form of beaten cellulose pulp and an apparatus for producing the same. This pulpy chitosan fiber can be used as a binder for cellulose pulp, synthetic fibers, inorganic fibers, etc., and also for immobilizing enzymes or bacterial cells such as yeast.

Conventional technology chitin can be found in crustaceans such as shrimp and crabs, insects such as beetles,
It exists in the cell walls of fungi, etc., and is widely produced in nature in large quantities, second only to cellulose. Its chemical structure is a polysaccharide represented by poly[β(1-4)-2-acetamido-2-deoxyglucan]. be. However, compared to cellulose, which is widely used in various fields, chitin has hardly been used.

When chitin is hydrolyzed with concentrated sodium hydroxide solution,
Deacetylation occurs and chitosan is produced. Those with a degree of deacetylation of 70% or more are generally called chitosan. Chitosan does not dissolve in alkalis or ordinary organic solvents, but it does dissolve in dilute acids. As a method for producing chitosan fibers using chitosan as a raw material, a method has been proposed in which chitosan is dissolved in an acetic acid aqueous solution, extruded through pores into a coagulating liquid, and stretched to produce chitosan fibers (Japanese Patent Application Laid-Open No. 1983-1999-1). 26
Publication No. 049). However, chitosan fibers obtained by this method have drawbacks such as low strength when made into paper alone and the need to add a large amount of binder.

In addition, a method has also been proposed in which powdered chitosan is dispersed in water and passed through a high-pressure homogenizer to produce a chitosan suspension, and then the chitosan suspension is made into paper (Japanese Patent Laid-Open No. 1983-1982-1). 84938). However, this method requires special equipment called a high-pressure homogenizer, so
In addition to the high manufacturing cost, the harsh conditions such as applying high shear force at high temperatures lead to the cleavage of glucosidic bonds in chitosan.

A method for producing a chitosan-based paper product was proposed in which a chitosan suspension was prepared by adding an alkali metal hydroxide to a dilute acid aqueous solution of chitosan under stirring, and then papermaking was made from this suspension (Japanese Patent Application Laid-Open No. 1989-1993).
3-59499). However, this method requires stirring with a household mixer! Rice and chitosan become colloidal, and the fine particles clog the wire mesh during paper making.
There were problems such as difficulty in dehydration.

As described above, in order to use chitosan fibers as a raw material for paper, there are problems with the structure of the fibers, the strength of the paper is low, and it is necessary to add a large amount of binder.

Problems to be Solved by the Invention The present invention solves the following problems by producing branched water-retentive chitosan fibers such as beaten cellulose pulp.
It has been discovered that the above-mentioned drawbacks can be overcome. An object of the present invention is to provide a method and apparatus for producing fibers such as known cellulose bulbs in a simple manner.

Means for Solving the Problems As a result of intensive study on a new manufacturing method that is industrially advantageous as an alternative to the conventional manufacturing method for chitosan fibers, the present inventors found that an acid such as acetic acid was added to the chitosan aqueous dispersion. When this chitosan solution is added continuously or intermittently to the middle of the coagulating liquid flowing as two continuous laminar flows from two opposing directions, surprisingly, the refining Like cellulose pulp, pulpy chitosan with a branched fiber length of 11II+ or more is produced, and when this is made into paper by a normal method, it has good texture and excellent strength properties, and is a high-density chitosan-based paper. It was discovered that paper products can be easily obtained, leading to the completion of the present invention.

That is, in producing chitosan fibers by bringing a chitosan solution and a coagulating liquid into contact in a predetermined contact zone, the present invention applies the coagulating liquid to the contact zone as two continuous laminar flows from two opposing directions. The chitosan solution is continuously or intermittently introduced into the contact zone, and the chitosan solution is simultaneously coagulated and fibrous, thereby producing pulp. A method for producing chitosan fibers, an upwardly open container filled with a coagulation liquid, four rotating rollers arranged vertically in two rows and two rows at approximately equal intervals in the container, and each adjacent roller rotates in the opposite direction. a drive mechanism for causing the
The present invention provides an apparatus for producing pulp-like chitosan fibers, which comprises a chitosan solution introduction tube that opens toward the approximate center of a rotating roller of a book.

The present invention will be explained in detail below.

Examples of the chitosan used in the present invention include commercially available chitin or chitosan with a deacetylation degree of 70% or more obtained by deacetylating chitin collected from shrimp shells, crab shells, etc. by a conventional method. Also included are low-molecular-weight chitosans obtained by treating these chitosans with mineral acids or oxidizing agents. Examples of solvents for dissolving chitosan include aqueous solutions of organic acids such as formic acid and acetic acid, and mineral acids such as hydrochloric acid. Further, as the coagulating liquid, an alkaline aqueous solution or alkaline methanol solution of amines such as sodium hydroxide, calcium hydroxide, and ethylenediamine is used.

Next, the manufacturing apparatus of the present invention will be explained according to the accompanying drawings.

FIG. 1 is a perspective view showing the main parts of the apparatus of the present invention, and FIG. 2 is a plan view. 4 rolls placed 1
．． 1 and 1.1, and these rolls are driven by a required drive mechanism, e.g. a motor (not shown), so that the adjacent rolls rotate in opposite directions, i.e. in the directions of the respective arrows. It is configured. This rotational speed can be adjusted, for example, in the range of 0 to 1500 rpm+. In this way Roll 1.1.1.
When rotating l, the coagulating liquid moves inward from the direction A and A in Figure 2 toward the center 3 of the coagulation tank 2, and from this point changes direction in the direction B and B and moves outward. do. In this way, a laminar flow without turbulence is created.

When a chitosan solution is continuously or intermittently dropped into this central part 3 through an introduction tube 4, the chitosan solution is stretched from side to side and solidified, resulting in branched fiber lengths 1
Chitosan fibers of i+m or more are obtained. This pulp-like chitosan fiber is thoroughly washed with water using a 200-mesh wire mesh. In pulp-like chitosan fibers produced under optimal conditions, only fibrous materials are obtained with almost no fine particles passing through the 200-mesh wire gauze.

Pulp-like chitosan fibers in the present invention can be prepared, for example, by the following methods, but are not limited to these specific examples.

First, the chitosan concentration is 0.1-10%, preferably lO
A dilute acid aqueous solution of chitosan is prepared to have a concentration of ~2000 cp. Next, a coagulating liquid such as an aqueous sodium hydroxide solution is placed in the coagulating bath of the pulp chitosan manufacturing apparatus, and the rolls are rotated. A dilute aqueous chitosan acid solution is dropped continuously or intermittently near the center of the four rolls. Although it varies depending on the concentration of chitosan, if the rotation speed of the roll is slow, it tends to become bead-like or bead-like, and if the rotation speed is too fast, it tends to become colloidal. However, 500~1300r
At rotation speeds of pm, branched pulpy fibers are obtained. Examining the effect of chitosan concentration at the optimal rotation speed, we found that at low concentrations, the fibers become fine scales, at high concentrations they become bead-like, but at the optimal concentration, pulp-like chitosan fibers are obtained. It is also possible to increase the optimum concentration of low-molecular chitosan. 5% sodium hydroxide was suitable as the coagulation liquid.

The pulp-like chitosan fibers of the present invention obtained by such a method have high water retention properties1 like beaten pulp, and also have excellent dispersibility in water. After washing with water, this pulp-like chitosan fiber paper mackerel is used alone or mixed with cellulose, and JISP 8
Paper can be made according to the 209 method.

The pulp-like chitosan fibers according to the present invention can be made into paper using a conventional paper-making method, and the paper obtained has a paper-like appearance with high density and high water resistance. In addition, even in mixed papermaking with cellulose bulbs, paper can be easily made and paper with high water resistance can be produced.

Effects of the Invention The method for producing pulp-like chitosan fibers according to the method of the present invention is an excellent method that is simple and can be produced without cutting the fibers.

Pulp-like chitosan fibers prepared by this method are composed of branched fibers similar to beaten cellulose bulbs, have high water retention and good water dispersibility, and can be widely used in the same applications as cellulose bulbs. Therefore, it can be expected as a new type of chitosan fiber. In addition, compared to cellulose bulbs which exhibit anionic properties, the pulp-like chitosan fibers of the present invention exhibit cationic properties and can be used as a binder or mixed with cellulose bulbs, etc., and can also be used as a binder for enzymes and bacterial cells. It has great potential for a wide range of applications, including use as immobilization carriers, separable sheets, etc.

Example Next, the present invention will be explained in detail by way of examples.

Example 1 Chitosan with a degree of deacetylation of 100% (viscosity of 0.5% chitosa 7-0.5% acetic acid aqueous solution is 385 cp/20°
C) 1243 g of water was added to 15 g to prepare a chitosan dispersion, and 1243 g of a 1% acetic acid aqueous solution was added thereto and stirred for 2 hours to prepare a 0.6% chitosan solution.

The viscosity of this chitosan solution was 419 cp/20°C. This solution was filtered and degassed, and then placed in a separatory funnel equipped with a nozzle having an inner diameter of lam.

Next, 5%
Add an aqueous solution of sodium hydroxide and place 4 rolls into 8
It was rotated at 00 rpm. A chitosan solution was intermittently dropped into the center from a separatory funnel to produce pulp-like chitosan fibers with an average fiber length of 1111 or more. 200% of this fiber
The mixture was placed in a mesh sieve, thoroughly washed with water, and paper was made according to the JIS method. Note that no colloidal substances passed through the sieve during washing with water. The obtained paper has a thickness of 0.06 mm,
Density 0-92g/crm3, breaking length 1.54k
It's m;.

Example 2 Using the chitosan used in Example I, the chitosan concentration and the manufacturing conditions of pulp-like chitosan fibers were investigated. The results are shown in Table 1.

Table 1 As is clear from Table 1, when the concentration of chitosan is low, it becomes dissolved or colloidal, and when the concentration is high, it becomes bead-like. When examining the influence of coagulation bath concentration under optimal conditions, it was found that the concentration of sodium hydroxide should be 1% or more, and 5% concentration was optimal.

Example 3 The chitosan used in Example 1 was hydrolyzed with mineral acid,
Chitosan has been reduced to a lower molecular weight. When dissolved in 0.5% acetic acid to give a concentration of 5%, the viscosity (at 20°C) is 92 (A).
and 14(B) cp. Table 2 shows the results of examining the manufacturing conditions for pulp-like chitosan fibers using this low-molecular-weight chitosan.

From Table 2, it was confirmed that pulpy chitosan fibers could be easily obtained by increasing the concentration of the chitosan solution.

Example 4 The pulp-like chitosan fiber obtained in Example 1 and NBKP were mixed into paper. It was found that as the pulpy chitosan fibers increased, the density of the paper obtained increased, and the colloidal substances in the white water, which is wastewater from papermaking, decreased significantly.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a pulp chitosan fiber manufacturing apparatus applied to carry out the method of the present invention, and Figure 2 is a flow of coagulation liquid when the rolls in the bulb-shaped chitosan fiber manufacturing apparatus are rotated. shows. In the figure, numeral 1 is a roll, 2 is a coagulation bath, 3 is a center part, 4 is a chitosan solution introduction tube, and A and B are the flow direction of the coagulation liquid.

Claims (1)

[Claims] 1. When producing chitosan fibers by bringing a chitosan solution into contact with a coagulation liquid in a predetermined contact zone, the coagulation liquid is introduced into the contact zone in two continuous laminar flows from two opposing directions. and discharge the respective laminar flows in the contact zone while changing direction approximately at right angles, and
A method for producing pulp-like chitosan fibers, characterized in that a chitosan solution is continuously or intermittently introduced into the contact zone, and simultaneously coagulated and turned into fibers. 2. An upwardly open container filled with a coagulating liquid, 4 rotating rollers arranged vertically in 2 rows and 2 rows at approximately equal intervals in the container, a drive mechanism for rotating each adjacent roller in the opposite direction, and 4. This is a pulp chitosan fiber manufacturing device consisting of a chitosan solution introduction tube that opens toward the center of a rotating book roller.