JPH0341105A - Chitosan-containing particle and its production - Google Patents

Abstract

PURPOSE:To produce a chitosan-containing particle having a suitable softness, improved mechanical strengths and a freely controllable particle diameter by dissolving chitosan in a specified monomer and polymerizing the solution in water in the presence of a polymerization catalyst. CONSTITUTION:An aqueous solution containing chitosan of a degree of deacetylation >=30% is mixed with an aqueous solution containing a monomer which can dissolve chitosan (e.g. acrylic acid) in a weight ratio of the chitosan to the monomer >=1% to obtain an aqueous solution in a state in which the chitosan is dissolved in the monomer. After a polymerization initiator (e.g. potassium persulfate) and optionally an emulsifier and a dispersion stabilizer are added to this aqueous solution, the resulting mixture is reacted for 2-12hr at 20-80 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a new method for producing chitosan-containing granules and the chitosan-containing granules obtained thereby.

[Conventional technology]

Chitosan is a basic polysaccharide obtained by deacetylating chitin present in the carapace of crustaceans such as crabs and shrimps by treating it with concentrated alkali. Due to its unique properties, chitosan is being developed and researched as a variety of adsorbents, medical carriers, medical materials, etc.

For example, in order to put chitosan into practical use as a variety of carriers, the technology to granulate it is important.

Conventionally, a method for granulating chitosan is to dissolve chitosan in an acid and then drop this solution into an alkaline coagulation solution (Japanese Unexamined Patent Publication Nos. 59-30722 and 1983-62).
62827, JP-A-62-70401, JP-A-62-79201, etc.) and a method of mechanically treating chitosan solutions and chitosan dispersions (JP-A-62-70401, JP-A-62-79201, etc.);
-20302, Japanese Patent Application Laid-Open No. 17902/1983.

(see Japanese Patent Laid-Open No. 63-210101, etc.).

[Problem to be solved by the invention]

However, all of these granulation methods have the disadvantage that the particle size of the obtained granules is relatively large and the granules are very hard and brittle, which limits their applications. .

[Means to solve the problem]

In this invention, chitosan-containing granules obtained by dissolving chitosan in a certain monomer and polymerizing the solution have appropriate flexibility and excellent mechanical properties. They discovered that the particle size can be freely controlled and attempted to solve the above problem.

The present invention will be explained in detail below.

The chitosan used in this invention is (l→4)
A deacetylated product of chitin having a -2-acetamido-2-deoxy-β-D-glucan structure, (l→
4) It has a -2-amino-2-deoxy-β-D-glucan structure, and in this invention, some of the deacetylated amine 7 groups or some of the hydroxyl groups in the same molecule are acyl. It also includes chitosan derivatives that have been chemically modified by chemical reactions such as chemical reactions, etherification reactions, esterification reactions, and other reactions. Generally, in naturally occurring chitin, a portion (approximately 10%) of the acetamido groups are non-acetylated amino groups. point to something

This chitosan can be used as it is in the form of flakes, or in the form of a solution dissolved in an aqueous acid solution such as an organic acid such as acetic acid, lactic acid, formic acid, propionic acid, butyric acid, or a mineral acid such as hydrochloric acid or nitric acid. You can also use

Further, the monomer used in this invention may be any monomer as long as it can dissolve chitosan, and preferably a water-soluble organic acid having a reactive vinyl group in the molecule is used. This organic acid may be a -basic acid or a polybasic acid, and has one or more reactive vinyl groups in its molecule, and specifically includes acrylic acid, α-chloroacrylic acid, methacrylic acid, α- Examples include ethyl methacrylic acid, fumaric acid, maleic acid, itaconic acid, 2(meth)acryloyloxyethyl acid phosphate, and t-butylacrylamide sulfonic acid.

The polymerization catalyst used in this invention may be any catalyst capable of initiating polymerization of the above monomer in water, and specific examples include potassium persulfate, ammonium persulfate, hydrogen peroxide, and alkyl hydroxy peroxide. Further, depending on the case, reducing agents such as sodium bisulfite, pyrosulfite, and ferrous sulfate may be used in combination. The amount of polymerization catalyst used is 0.05 to 10% by weight based on the monomer.
It is said that

The mixing ratio of chitosan and the above monomer is arbitrary, with the upper limit being the maximum amount of chitosan that can be dissolved by the monomer, but preferably the weight ratio of chitosan to the monomer is 1.
% or more. If it is less than 1%, the resulting granules will not have the characteristics of chitosan.

In the polymerization operation, chitosan and the above monomer are each dissolved in water in predetermined amounts and stirred. As a result, chitosan becomes dissolved in Moamer and becomes an aqueous solution. A polymerization catalyst is added to this aqueous solution to initiate polymerization. Emulsifiers and dispersion stabilizers can be used to stabilize the polymerization reaction system and control the particle size of the granules. When using the above-mentioned acid aqueous solution as chitosan, monomers and water are added to it to obtain a predetermined concentration, and then a polymerization catalyst is added to carry out polymerization.

Furthermore, if necessary, a water-soluble monomer such as acrylamide can be added within a range that does not impair the solubility of chitosan, and the resulting granules can be modified.

The polymerization temperature is 20 to 80°C and the polymerization time is about 2 to 12 hours, but is not limited to this range. After the polymerization is completed, a suspension of the chitosan-containing polymer in water is obtained, which is separated into solid and liquid by a conventional method and dried to obtain the intended chitosan-containing granules.

The chitosan-containing granules obtained in this way have a morphology in which chitosan is surrounded by a polymer, and exhibit the characteristics of -t-tosan as well as the properties of polymer particles, with appropriate It becomes flexible.

Therefore, this chitosan-containing particulate material can be used as an adsorbent for gel chromatography, ion exchange chromatography, etc., dialysis material, ion exchanger, enzyme immobilization carrier, bioreactor carrier, medical carrier, medical aid, etc. It can be used for
Since it is less brittle than conventional chitosan granules, it is easy to handle, has no fear of breakage, and has a long life.

In addition, since the suspension after polymerization is dilutable with water, it can be mixed with other water-soluble polymers, and paper, fibers, etc. can be impregnated with the suspension alone or in a mixture with other water-soluble polymers. A coating of chitosan-containing polymer can be obtained. Further, by drying this suspension, a molded body such as a water-insoluble chitosan-containing film or sheet can be obtained.

Hereinafter, a specific explanation will be given by showing examples.

(Example 1) 8 g of flaky chitosan (degree of deacetylation 81°2%, viscosity 7 cps, in 1% acetic acid solution, 20°C),
1L of water-soluble i& consisting of 8g of methacrylic acid and 500g of water.
A four-eye flask was charged, and the inner crystal was heated to 70'C while stirring and purging with nitrogen gas. While maintaining the internal temperature at this temperature, an aqueous solution consisting of 0.5 g of potassium persulfate and 10 g of water was added overnight, and the mixture was maintained at 70°C for 2 hours.

The temperature was further raised to 80°C over 30 minutes and maintained for 2 hours to complete the reaction, and after cooling, a chitosan-containing fine particle suspension was obtained. This suspension was poured into acetone, separated into solid and liquid using a centrifuge, and dried to obtain chitosan-containing fine particles having a particle size of 1OOμ or less. In addition, the nitrogen content of these fine particles is 3°52%.
Met. Further, a chitosan-containing film was obtained by casting this suspension onto a glass plate and drying it.

(Example 2) Acrylic acid was used instead of methacrylic acid in Example 1 to obtain chitosan-containing fine particles and a film. The nitrogen content of the obtained particles was 3.65%.

(Example 3) Chitosan flakes (degree of deacetylation S 12%, viscosity 7 cps, in 1% acetic acid solution, 20°C) log,
An aqueous solution consisting of 8 g of itaconic acid and 500 g of water was charged into a L four-eye flask, and the internal temperature was raised to 70° C. while stirring and purging with nitrogen.

While maintaining the internal temperature at this temperature, add 0.5 g of potassium persulfate.
, an aqueous solution consisting of 10 g of water was added and held for 1 hour, then an aqueous solution consisting of 0.5 g of sodium bisulfite and 10 g of water was added and held for 1 hour.

After further holding at 70°C for 30 minutes, the temperature was raised to 80°C.
The reaction was completed by holding for 2 hours, and after cooling, a chitosan-containing fine particle suspension was obtained. Pour this suspension into acetone,
Solid-liquid separation was performed using a centrifuge, and the mixture was dried to obtain chitosan-containing fine particles having a particle size of 1OOμ or less. Further, the nitrogen content of these particles was 4.01%.

(Example 4) Chitosan flakes (degree of deacetylation 78%).

Viscosity 1] 0 cps However, in 0.5% acetic acid, 20'C
) An aqueous solution consisting of Ig, 2 g of methacrylic acid, and 500 g of water was charged into an IL four-way flask, and the internal temperature was raised to 70'C while stirring and purging with nitrogen. At this temperature, while controlling the internal temperature, add an aqueous solution consisting of 0.3 g of potassium persulfate and 10 g of water, hold for 2 hours, then raise the temperature to 80°C over 30 minutes and hold for 2 hours to complete the reaction. After cooling, a chitosan-containing fine particle suspension was obtained. Chitosan-containing beads of 200 μm or less were obtained by processing according to the method of Example 1. Further, the nitrogen content of these particles was 2.19%.

(Example 5) Chitosan flakes (degree of deacetylation 78%).

Viscosity 110 cps However, in 0.5% acetic acid solution at 20'C
), 2.5 g of methacrylic acid, and 500 g of water were charged into a four-eye IL flask, and while stirring and purging with nitrogen, the internal temperature was raised to 70'C. While controlling the internal temperature at this temperature, add 0.3 g of potassium persulfate and 1 liter of water.
An aqueous solution consisting of 0 g of bisulfite was added and held for 30 minutes, then an aqueous solution consisting of 0.3 g of bisulfite and log water was added and held for 5 hours. Next, the temperature was raised to 80'C over 30 minutes, maintained for 2 hours to complete the reaction, and cooled to obtain a chitosan-containing fine particle suspension. Chitosan-containing beads of 150 μm or less were obtained by processing according to the method of Example 1.

Further, the nitrogen content of these particles was 3.49%.

(Example 6) 10 g of flaky chitosan (degree of deacetylation 81°2%, viscosity 7 cps, in 1% acetic acid solution, 20'C)
, an aqueous solution consisting of 8 g of methacrylic acid and 500 g of water was IL
A four-eye flask was charged, and the internal temperature was raised to 50'C while stirring and purging with nitrogen. While controlling the internal temperature at this temperature,
lpropiona@1dine) dihydroch
An aqueous solution consisting of 5 g of lorideO and 10 g of water was added and held for 20 minutes. Next, the internal temperature was raised to 70°C,
2゜2'-Azobis(2-meLhylprop
ionamidine) dihydr.

An aqueous solution consisting of 5 g of chloride O and 10 g of water was added and held for 50 minutes. Next, the internal temperature was raised to 80° C. over 30 minutes, maintained for 2 hours to complete the reaction, and after cooling, fine particle beads containing chitosan were obtained. Example 1
Chitosan-containing microparticle beads of 200 μm or less were obtained by the method described above. Further, the nitrogen content of these particles was 3468%.

(Example 7) 30 g of flaky chitosan (deacetylated [81°2%, viscosity 7 cps, in 1% acetic acid solution, 20°C),
An aqueous solution consisting of 10 g of acetic acid and 400 g of water was charged into a four-eye IL flask, and the internal temperature was raised to 70'C while stirring and purging with nitrogen gas.

While maintaining the internal temperature at this temperature, potassium persulfate Ig,
Add an aqueous solution consisting of 20 g of water, then add acrylic acid 3
0 g was added dropwise over 30 minutes.

After keeping the internal temperature at 70°C for 1 hour, an aqueous solution consisting of sodium bisulfite Ig and 20g of water was added,
The temperature was raised to ℃. The reaction was completed by holding at 80'C for 1.5 hours, and the mixture was cooled to obtain a chitosan-containing fine particle suspension. Chitosan-containing beads of 100 μm or less were obtained by processing according to the method of Example 1. The nitrogen content of these particles was 3.62%.

〔Effect of the invention〕

As explained above, the chitosan-containing granules of the present invention are obtained by polymerizing a composition containing chitosan and a monomer capable of dissolving chitosan, and therefore have a form in which chitosan is wrapped in polymer chains. The result is a granular material with appropriate flexibility. Further, by selecting the polymerization conditions, the particle size can be arbitrarily set within a wide range.

Claims (2)

[Claims] (1) Chitosan-containing granules obtained by polymerizing a composition containing chitosan and a monomer capable of dissolving chitosan. (2) A method for producing chitosan-containing granules, which comprises dissolving chitosan in a monomer that can dissolve it, and polymerizing it in water in the presence of a polymerization catalyst.