JPH0485367A - Color pigment based on chitosan - Google Patents

Abstract

PURPOSE:To obtain a color pigment having a stable color tone by treating chitosan with a specified naphthoquinone compound or anthraquinone compound. CONSTITUTION:A solution of a naphthoquinone compound of formula I (wherein R<1> and R<2> are each H, halogen, hydroxyl, lower alkyl or a sulfonate salt group or an anthraquinone compound of formula II in an organic solvent is added to a water bath, and chitosan is dispersed therein and treated at 60-90 deg.C for 30min to 2hr. An aqueous alkali of a concentration of 5-20wt.% is then dropped therein to deposit a color pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a new colored pigment made from chitosan, more specifically, a colored pigment made from chitosan which is obtained by treating chitosan with a naphthoquinone compound or an anthraquinone compound. It concerns pigments.

Conventional technology Crab shells and shrimp shells contain 25-35% chitin, and these shells are treated with alkali to remove proteins and pigments.
It is known that chitin can be obtained by removing ash such as carbon calcium with acid treatment, and that chitosan can be obtained by further deacetylating this chitin with alkali treatment.

In recent years, such chitin and chitosan have attracted attention as one of the unused marine resources and are being used for various purposes.More recently, research has been actively conducted on the use of chitin and chitosan as functional materials, for example in agriculture. In the field, chitosan mixed with organic acids and special amino acids has the effect of propagating actinomycetes in the soil, increasing the absorption efficiency of phosphoric acid by plant roots, and activating plants by generating ethylene. Because of this, it has been put into practical use. In the food and pharmaceutical fields, the development of functional foods and medicines that utilize the cholesterol-lowering effect of chitosan is underway.
Furthermore, natural preservatives containing chitosan and organic acids as active ingredients have been developed as food additives by taking advantage of the synergistic effect between the antibacterial properties of chitosan and the bacteriostatic properties of organic acids. On the other hand, in the cosmetics field, attempts have been made to utilize chitosan as a cosmetic material by taking advantage of its excellent moisturizing and water-retaining properties. The material has already been commercialized as a cosmetic raw material.

Furthermore, functional separation membranes that utilize the hydrophilic properties of chitosan,
It is useful for the production of high-purity alcohol, ethanol concentration in the fermentation industry, dehydration and purification of mixed organic solvents, regeneration of alcoholic solvents in the organic synthetic chemical industry, dehydration from bioreactor systems using enzymatic reactions, etc. It is expected that there will be.

As described above, chitin and chitosan have attracted attention as functional materials useful for various uses, and research and development of new uses has been actively conducted.However, there have been few attempts to use chitosan as a material for colored pigments. Ta.

Problems to be Solved by the Invention The present invention has been made for the purpose of providing a new colored pigment made from chitosan as a new use for chitosan.

Means to Solve the Problem The inventors of the present invention have conducted intensive research to develop a colored pigment made from chitosan, and have discovered that a black pigment can be obtained by first treating chitosan with a purple pigment. I found out.

As a result of further research, the present inventors discovered that colored pigments with various stable color tones could be obtained by treating chitosan with a certain naphthoquinone or anthraquinone compound, and based on this knowledge, As a result, the present invention was completed.

That is, the present invention provides chitosan with the general formula (R1
and R2 are a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkyl group, or a salt-type sulfonic acid group, respectively. It provides colored pigments.

The present invention will be explained in detail below.

Chitosan, which is used as a material for the pigment of the present invention, is obtained by removing minerals such as calcium carbonate and proteins from the shell chitin of crustaceans, which are widely found in nature, such as crabs and shrimps. It is obtained by deacetylation with an alkali and has a structure in which D-glucosamine is linked to β-(1,4)-.

The chitin is a polysaccharide having a long linear structure of a large number of N-acetyl-D-glucosamine residues linked to β-(1,4), represented by the general formula, while chitosan has the above-mentioned General formula (nI
) A large number of D-glucosamines are β-(1,4
) is a polysaccharide with a structure similar to long linear cellulose linked together.

Ordinary chitosan is not 100% deacetylated and contains some acetyl groups.

The chitosan used in the present invention has the general formula (IV)
As shown, chitosan may be completely deacetylated in the acetamide group bonded to the 2-position of chitin, or depending on the degree of deacetylation of chitin, the molecule may contain the general formula (III). It may also be a partially deacetylated chitosan in which an unspecified portion of N-acetyl-D-glucosamine residues as shown in the following formula remain.

The molecular weight of chitosan is determined by the processing conditions used to separate chitin by removing minerals and proteins from the chitin of crustacean shells, and by the glyconolytic bond between molecules when deacetylating chitin with alkali. It depends on how much the bond is broken, but usually 100,000
It is about 0 to 350,000.

As chitosan in the present invention, water-insoluble finely powdered chitosan may be used, gel-like chitosan salt may be used, and water-soluble chitosan, chitosan oligosaccharide, D-glucosamine, or their inorganic acids may be used. Salts or organic acid salts may also be used.

As water-insoluble chitosan, the molecular weight is 100,000~
Water-insoluble chitosan with a high molecular weight of around 350,000, or chitosan with such a high molecular weight is further partially hydrolyzed with an acid such as hydrochloric acid to reduce the molecular weight, or Str
eptomyces sp, No. 6 and Pen ic
i l l iumislandicum QN 7
It has a molecular weight of 20,000 to 30, which has been reduced to a low molecular weight by enzymatic decomposition with chitosanase produced from 571.
One example is chitosan, which has a medium molecular weight of about 1,000 yen. By using such water-insoluble chitosan, a finely powdered colored pigment can be obtained.

A gel-like chitosan salt is prepared by dissolving the above water-insoluble chitosan in a dilute aqueous solution of an inorganic or organic acid. As acids for dissolving water-insoluble chitosan, inorganic acids such as hydrochloric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, oxalic acid, acetic acid, propionic acid, lactic acid, malic acid, succinic acid, and adipic acid are used.

The acid concentration is preferably 0.5 to 5% (W/V%). When water-insoluble chitosan is dissolved in an acid diluted aqueous solution, the viscosity of the solution increases and becomes gel-like. Therefore, the concentration of water-insoluble chitosan dissolved in these acid-diluted aqueous solutions is not limited as long as the resulting gel has fluidity, but the concentration of water-insoluble chitosan dissolved in acid-diluted aqueous solutions is 0.5 to 3.
% (W/V%) is preferred. By using such a gel-like chitosan salt, a gel-like colored pigment can be obtained.

As the water-soluble chitosan, water-soluble chitosan having a molecular weight of 200 to 10,000 is used, which is obtained by hydrolyzing or enzymatically decomposing water-insoluble chitosan to reduce its molecular weight. Chitosan oligosaccharides include chitobiose, chitotriose, chitotetraose, chitopentaose, chitohexaose, chitoheptaose, in which the degree of polymerization of chitosan is 2 to 8 (n in the general formula (TV) is O to 6); Examples include chitooctaose. D-glucosamine is obtained as a hydrochloride salt by completely hydrolyzing chitin with concentrated hydrochloric acid, and when used, a portion of this is diluted with an alkali. These water-soluble chitosan, chitosan oligosaccharide and D-glucosamine may be in the form of an inorganic acid salt or an organic acid salt. As the acid used for forming the salt, the same acid as the above-mentioned inorganic acid or organic acid used for preparing the gel-like chitosan salt is used. When such water-soluble chitosan, chitosan oligosaccharide, D-glucosamine, or their inorganic or organic acid salts are used, a liquid colored pigment can be obtained.

The colored pigment of the present invention is obtained by treating the chitosan with a toquinone compound represented by the general formula (R1 and R2 in the formula have the same meanings as above) or an anthraquinone compound represented by the general formula. It is obtained by Examples of the so-7-toquinone compounds represented by the general formula (I) include σ-7-toquinone, 2-methyl-1,4-naphthoquinone, (2), 4-naphthoquinone-2-potassium sulfonate, and 2,3-dichloroquinone. oa-1,4-7toquinone, 2-
Examples of anthraquinone compounds represented by the general formula (I[) include 1,4-dihydroxyanthraquinone (quinizarin), 1,2-dihydroxy Examples include anthraquinone (alizarin).

These compounds may be synthetic products or natural products, and examples of natural products include, for example, Lythraceae Law
Examples include lauson extracted from the leaves of sonia arba Lam, and alizarin obtained from the roots of madder.

In order to obtain a finely powdered colored pigment by treating water-insoluble chitosan with the above-mentioned naphthoquinone compound or anthraquinone compound, a solution of the quinone compound dissolved in an organic solvent is usually added to a water bath and heated. This is done by dispersing powdered water-insoluble chitosan in the dye bath while stirring.

The dye bath is preferably neutral or weakly alkaline; if it is acidic, water-insoluble chitosan will dissolve. The pH of the dye bath obtained by adding a solution of the quinone compound in an organic solvent to a water bath is weakly acidic at 4 to 6. However, chitosan has its own buffering capacity based on free amino groups, so When water-insoluble chitosan is added to the dye bath, the pH of the dye bath conveniently shifts to the alkaline side and is adjusted to a range of I) H6 to 8.

Therefore, chitosan can be dyed while remaining water-insoluble without preparing po with an alkaline aqueous solution or the like.

When dyeing is carried out at a predetermined temperature for a predetermined time, the water-insoluble chitosan in the dye bath is colored in a predetermined color. The desired finely powdered colored pigment can be obtained by filtering and fractionating the colored chitosan and drying it, or if necessary, grinding it with a wet grinder and then drying it.The colored pigment obtained can be finely ground. It does not turn white or become brighter even when applied, and has excellent fastness.

To obtain a gel-like colored pigment by treating chitosan salt with the quinone-based compound, a solution of the quinone-based compound dissolved in an organic solvent is usually added to a water bath, and the gel-like pigment is added to the heated dye bath. Add chitosan salt and stir the dye bath in which gel-like chitosan salt is dissolved, or dilute an inorganic or organic acid with water in the dye bath and dissolve a predetermined amount of water-insoluble chitosan in the dye bath to form a gel. A method is used in which a chitosan salt is prepared, a solution of the quinone compound dissolved in an organic solvent is added thereto, and the dye bath is heated while stirring.

Since the gelled chitosan salt added to the dye bath has a pH of 4 to 5, dyeing is performed at a pH of 4 to 5 of the dye bath. By dyeing at a predetermined temperature for a predetermined time, the solution in which the gelled chitosan salt is dissolved in the dye bath becomes colored. A desired gel-like colored pigment can be obtained from this colored solution by concentrating the solvent under reduced pressure to a required viscosity state.

The gel-like colored pigment thus obtained may be used, for example, by contacting with an aqueous alkaline solution to obtain a powdered colored pigment, or by treating a finely powdered polymeric substance to obtain a polymer-based colored pigment. It can be used to obtain or dye fibers, etc.

To obtain a liquid colored pigment by treating water-soluble chitosan, chitosan oligosaccharide, D-glucosamine, or their inorganic or organic acid salts with the quinone compound, the quinone compound is usually dissolved in an organic solvent. A method of adding and dissolving water-soluble chitosan, chitosan oligosaccharide, or D-glucosamine or their inorganic or organic acid salts into a heated dye bath and stirring the dye bath; A method is used in which chitosan, chitosan oligosaccharide, D-glucosamine, or their inorganic or organic acid salts are dissolved in water, and a solution of the quinone compound dissolved in an organic solvent is added thereto and heated while stirring. It will be done.

When water-soluble chitosan, chitosan oligosaccharide or D-glucosamine is used, the pH of the dye bath is neutral around 7,
When these inorganic acid salts or organic acid salts are used, dyeing is carried out at a slightly acidic dye bath pH of 4 to 5.

By dyeing at a predetermined temperature for a predetermined time, the solution in the dye bath is colored in a predetermined color. This colored solution may be used as a liquid colored pigment as it is, or may be further concentrated to a required concentration by removing the solvent under reduced pressure to be used as a liquid colored pigment.

The liquid colored pigment thus obtained may be used as it is, or may be used to process a finely powdered polymeric substance to obtain a polymer-based colored pigment, or used to dye fibers, etc. It can be used for.

In the present invention, in order to prepare a colored pigment by treating chitosan with the quinone compound, a solution in which the quinone compound is dissolved in a suitable organic solvent is added to a water bath, and the mixture is poured into the dye bath while stirring. A method of adding chitosan is used. Examples of the organic solvent include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, ethylene glycol propylene gellicol, dimethyl ether, diethyl ether, isopropyl ether, dioxane, acetone, methyl isobutyl ketone, methyl ethyl ketone, ethyl acetate, dichloromethane, chloroform, carbon tetrachloride,
Usual organic solvents such as tricrene, perchlorene, benzene, and toluene can be mentioned, and these solvents may be used alone or in combination of two or more.

There is no particular restriction on the mixing ratio of water and organic solvent in the dye bath, but the amount of solvent in the dye bath in which water and organic solvent are mixed is usually 5 to 30 parts by volume per 1 part by weight of chitosan. selected within the range.

The amount of the quinone compound to be used varies depending on the degree of deacetylation of the chitosan and the type of quinone compound used, but it is preferably 3% by weight or more, preferably 10% by weight or more based on the chitosan. desirable. This usage amount is 3
Even if the amount is less than % by weight, a colored pigment having a desired color tone can be obtained by repeating the same dyeing process.

The dyeing temperature may be room temperature, but since it takes a long time for chitosan to be colored to the desired color, a temperature in the range of 60 to 90°C is preferable, and the dyeing time is about 30 minutes to 2 hours. is sufficient. Further, dyeing may be carried out using a dye bath equipped with a cooling pipe or the like while refluxing the solvent, or dyeing may be carried out in an open system while the solvent is diffused outside the system.

In this way, a colored pigment in the form of a fine powder, a gel, or a liquid is obtained, and the colored pigment in the form of a gel is brought into contact with an aqueous alkali solution.I: Therefore, a colored pigment in the form of a fine powder is obtained.

That is, if the gel-like colored pigment obtained as described above is simply dropped into an alkaline aqueous solution while stirring vigorously, a powdery colored solid will precipitate, and this colored solid will be filtered out, dried, and then pulverized. By doing so, a desired powdered colored pigment can be obtained.

Here, the alkaline aqueous solution used includes sodium hydroxide, potassium hydroxide, sodium carbonate, etc.
A 20% w/w aqueous solution is used. The temperature at which the gel-like colored pigment is brought into contact with the alkaline aqueous solution is not particularly limited, but is preferably in the range of 30 to 50°C. In order to make the particle size of the colored pigment that is precipitated and produced in contact with this alkaline aqueous solution fine, it is desirable to drop the gelled colored pigment under strong mechanical stirring.

Further, a colored thin film is formed from the gel-like colored pigment obtained as described above, and this is pulverized to obtain another colored pigment in the form of fine powder.

Furthermore, a powdered polymer-based colored pigment can be obtained by dyeing a powdered natural or synthetic polymer with the gel or liquid colored pigment obtained as described above.

Similarly, by dyeing natural or man-made fibers with gel or liquid colored pigments, fibers with the desired tone can be obtained.

Effects of the Invention According to the present invention, by treating chitosans with different molecular weights including D-glucosamine or their salts with a specific naphthoquinone compound or anthraquinone compound,
A fine powder, gel or liquid colored pigment with stable color tone is obtained.

If a powdered polymeric substance is treated with the gel or liquid pigment described above, a finely powdered polymer-based colored pigment can be obtained, and
By dyeing fibers with the above-mentioned gel or liquid pigments using a simple dip dyeing method, fibers having a desired color tone can be obtained.

The colored pigments can be used not only in the same fields as conventional colored pigments, but also have new functions, so new uses can be expected.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

The decomposition temperature and degree of deacetylation of chitosan were determined as follows.

(1) Deacetylation degree Q: 500 mg of chitosan was added and dissolved in a 5 wt% acetic acid aqueous solution 99.5+++ff. 1g of this solution is 2001
After adding 30 ml (l) of water and stirring thoroughly, 2 to 3 drops of 1 wt% methylene blue solution was added as an indicator, and the mixture was titrated with 1/400 normal potassium borihinyl sulfate. Based on this titration value. The degree of deacetylation was determined based on the following calculation formula.

V: Titration value of l/40ON polyvinyl potassium sulfate mQ f State/Titer of 40ON polyvinyl potassium sulfate Also,
The physical properties of the pigment obtained were determined as follows.

(2) Appearance By visual observation.

(3) Hue H1 Brightness v1 Saturation C A spectrophotometer using an integrating sphere [Spectrophotometer rUbest 50J, manufactured by JASCO Corporation] was used to measure wavelength 78
The reflection spectrum from 0 to 380 nm was measured, and the C light source (daylight including blue sky) was used as the standard light source, and the International Commission on Illumination (CI)
Using the color calculation program [TSV-433 type color calculation program manufactured by JASCO Corporation] that calculates the Munsell coordinates according to the color scale needle based on the 2-degree visual field determined in B), hue H1 brightness V, chroma are calculated. Measure the degree C.

Example 1 A dye bath was prepared by dissolving 5 g of α-naphthoquinone in 50 mQ of ethanol and adding it to 5 Qm12 of purified water to adjust the pH.
4,60, yellowish brown), then stir this.
Add 5 g of white powdered chitosan PSL C (manufactured by Yaizu Suisan Kagaku Kogyo Co., Ltd., trade name, decomposition temperature 267.7°C, degree of deacetylation 78.1%) and boil under reflux (80°C) for 6 hours.
After dyeing for 0 minutes, the solid content was filtered off and dried to obtain a pigment with a brown tone. Also,
The filtrate was dark brown in color and had a pH of 6.85. The results are shown in the table.

The infrared absorption spectrum of the pigment thus obtained is shown in FIG.

Examples 2 to 7 Example 1 was carried out using the compounds shown in the table and under the conditions shown in the table.
Powdered chitosan PSL was dyed in the same manner as above to prepare a pigment. The results are shown in the table.

In addition, the infrared absorption spectra of the obtained pigments are shown in Figure 2 (Example 2), Figure 3 (Example 3), Figure 4 (Example 4),
Figure 5 (Example 5), Figure 6 (Example 6) and Figure 7 (
Example 7).

[Brief explanation of drawings]

Figures 1 to 7 are colored pigments of the invention, respectively; It is an infrared absorption spectrum diagram of different examples of.

Claims (1)

[Scope of Claims] 1. Chitosan is defined by the general formula ▲ mathematical formula, chemical formula, table, etc. A colored pigment made from chitosan treated with a naphthoquinone compound represented by a sulfonic acid group. 2. A colored pigment made from chitosan, which is made by treating chitosan with an anthraquinone compound represented by the general formula ▲Mathematical formula, chemical formula, table, etc.▼.