JP2005281479A - Dye solution containing anthocyanin pigment and dyeing process using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently extract an anthocyanin pigment from a plant containing it to thereby provide a bright red dye solution excellent in storage stability; and a process for dyeing a protein substance in bright red by using the dye solution. <P>SOLUTION: The anthocyanin pigment can be efficiently extracted from a plant by using a water solution containing maleic acid and having a pH of 1.2 or lower. A dyeing solution prepared by incorporating an anthocyanin pigment into a water solution containing maleic acid and having a pH of 1.2 or lower is excellent in storage stability and can dye a protein substance brightly. By treating the resultant dyed substance with a salt of a metal selected from cobalt, nickel, and manganese, excellent color fastness is given to the dyed substance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stable dye solution of a plant anthocyanin pigment and a method for dyeing a protein substance such as a silk fiber product in a bright red color using the same.

  For the dyeing of red with plant pigments, the pigments of camellia, safflower and suou are used. However, as a typical pigment of flowers, anthocyanin pigments contained in fruits, leaves, and roots are pigments that produce distinctive and distinctive colors. It was supposed to be accompanied by technical difficulties.

  In order to use plant pigments for dyeing, except for special methods for indigo, safflower, etc., pigment extraction is generally performed by heating the dyeing material with water to extract water-insoluble pigments or rapidly. In the case of extraction, organic solvents such as alcohol have also been used. However, the extraction of anthocyanin dyes for dyeing is not effective by any of these methods, and it is not enough to use an aqueous solution of inorganic acid that is dangerous to handle, such as sulfuric acid. Since the efficiency is low, it has been impossible to dye textile products and the like with the obtained extract.

  There is an attempt to extract the anthocyanin pigment of the taro family taro with an acid aqueous solution having a pH of 1.5 to 4.0 (see Patent Document 1), but in this method, it is difficult to obtain a storage-stable product as a dye solution. In addition, using only the dye solution obtained by such a method, the textile product could not be dyed darkly with good fastness.

In addition, anthocyanin pigments isolated and extracted from living tissues of plants are subject to rapid photobleaching and are susceptible to degradation over time by enzymes, etc., and salts such as aluminum, iron, and copper are used as anthocyanin stains to prevent this. When the metal mordanting was applied, the dye was chelated with these metal ions and discolored significantly, and the vivid color unique to anthocyanins could not be reproduced.
JP-A-10-245499

  An object of the present invention is to provide a dyeing solution having an excellent storage stability containing an anthocyanin pigment, that is, to efficiently extract an anthocyanin pigment from a plant and provide a clear and practical red dye solution. At the same time, another object of the present invention is to provide a method for dyeing a protein substance into a bright red color with high fastness using an anthocyanin dye.

This inventor repeated earnest research so that the technique which satisfy | fills various conditions shown in the following (1)-(5) may be developed.
(1) A method for easily extracting an anthocyanin pigment for dyeing from a plant.
(2) A method in which long-term storage is effective while maintaining a state in which the extracted pigment can be stained.
(3) A method of bringing a commercially available anthocyanin dye into a state suitable for dyeing.
(4) A dyeing method that easily reproduces the color inherent to anthocyanins on an object to be dyed.
(5) A method for improving the color stability of anthocyanins after dyeing.

  In the present invention, it is possible to satisfy the conditions (1), (2), (3) and (4) by including an anthocyanin dye in an aqueous solution containing maleic acid and having a pH of 1.2 or less. Maleic acid is an organic dibasic acid that dissolves in water and exhibits strong acidity, and the pH value of 0.5% aqueous solution decreases to 1.1. While other polybasic acids (succinic acid, malonic acid, tartaric acid, citric acid, malic acid, glutaric acid, etc.) have the same pH value of 1.7 to 2.4, The acidity is by far the highest. Formic acid, which is the strongest organic acid, is a pungent and corrosive liquid and is dangerous to handle. Maleic acid is a strong acid but has low volatility, so it has little irritation. It is fine and easy to handle and highly safe. Therefore, by immersing a plant tissue containing anthocyanin in this aqueous maleic acid solution, the pigment is easily and safely extracted due to its strong acidity, and the purpose of (1) is achieved.

In addition, when the anthocyanin dye solution extracted with an aqueous maleic acid solution was refrigerated at 5 ° C. or less, it could be stably stored without any abnormality for about 1 to 2 years.
The reason is that the anthocyanin dye main body maintains a stable cation structure by keeping it at a low temperature under strongly acidic conditions, and the chromolytic enzyme that seems to coexist can be maintained in an inactivated state. In addition, because of the excellent antiseptic and antifungal effects of maleic acid, it is possible to prevent the decay of other plant components dissolved in addition to the pigment, so that the purpose of (2) is achieved. In addition, the pigment | dye main body here refers to the aglycone which excluded saccharide | sugar from the glycoside structure of a pigment | dye.

  Further, even when an aqueous solution of maleic acid and a commercially available anthocyanin dye are mixed, the same effect as the extract of (2) can be obtained.

  When the object to be dyed is immersed in a maleic acid extract of anthocyanin dye or a maleic acid mixture for a long time, the object to be dyed adsorbs maleic acid groups and is partially anionized. On the other hand, anthocyanin dyes, which are glycosides, are hydrolyzed by strong acids, and the sugars are gradually separated, and the dyes become cationic dye bodies. An effect | action arises and ion dyeing | staining becomes possible and the objective of (4) is achieved.

  If the dyed substance is an amphoteric substance such as a protein substance, it may be polarized to + beyond the isoelectric point if the pH value of the dyeing solution is low, and repulsion between the same species ions with the cationic dye molecule. Since the force works, dyeing of anthocyanin pigments is suppressed. If an acid dye made with an inorganic acid is used, it is difficult to dye. However, since the acid group of maleic acid is an organically large acid group consisting of 4 carbon atoms, it is easily adsorbed on the surface of the organic matter to be dyed, and the adsorbed surface is polarized to-. Therefore, + polarization of the object to be dyed is suppressed, and the dyeing deterrence based on the same kind of ions for the anthocyanin dye main body is gradually reduced. As a result, the dye body can be diffused and stained in the tissue of the protein substance, thereby achieving the purpose of (4).

  Anthocyanin dyes are improved in stability by chelating with metal ions, but may cause significant discoloration. However, when the anthocyanin dyed product according to the present invention is treated with a solution containing any salt of cobalt, manganese, and nickel, the degree of discoloration is small. Therefore, the purpose of (5) can be achieved.

By soaking plant tissue containing anthocyanin pigments in maleic acid aqueous solution at room temperature for a long time, the anthocyanin pigments for dyeing can be extracted easily, safely and efficiently, and the resulting extract can be stored for a long period of time. it can.
In addition, by immersing the dyed product for a long time in a dye liquor in which plant anthocyanin pigment and maleic acid coexist, the color of fresh anthocyanin can be easily dyed and treated with any salt of cobalt, nickel, or manganese. If it is re-dyed, it can be dyed to a more stable dark color, so it is possible to develop a unique dyeing field that can easily reproduce the color of dark anthocyanins that could not be obtained by conventional plant dyeing It became.
In the present invention, an anthocyanin pigment is extracted from a plant having an anthocyanin pigment, such as a flower, a leaf, and a skin (eg, kansui, sasanqua, morning glory, shiso, eggplant, red cabbage, autumn leaves, etc.), and a beautiful and beautiful red color is extracted. Not only can it be used as a dyeing solution, it can also be applied very efficiently to the use of commercially available anthocyanin dyes.
In addition, the protein substances dyed by the method of the present invention include all protein substances that can be dyed, such as protein fiber products such as raw silk and silk cloth, films made of protein substances, and coatings.

[Example 1]
Immerse the petal of agar with a large amount of anthocyanin, the main component of which is a cyanidin glycoside, in a 0.5% maleic acid aqueous solution (pH 1.1) approximately 5 times by weight at room temperature for more than one day. Extracted. The extract endured storage for 2 years in a refrigerator at 5 ° C.
In addition, the silk cloth is soaked in this extract (25-50 times the weight of the silk cloth by weight) at room temperature for one day and night, and salt is added to make a 0.5% solution, and further soaked at room temperature for one day and night. And washed with water. Thereafter, the dyed cloth was immersed in a 0.2% aqueous solution of cobalt sulfate at room temperature for 1 hour or longer, then washed with water, further immersed in the dyeing residual liquid for 2 days and nights, re-dyed and washed with water. The dyed fabric after re-dyeing exhibited a vivid wine red color characteristic of cyanidin.
Similar effects were obtained when nickel sulfate or manganese acetate was used instead of cobalt sulfate.

When the fastness to sunlight was measured, the color difference ΔE before and after exposure was as follows (this ΔE uses the color difference unit of the LAB color system based on the International Lighting Commission and JIS, and the smaller the value, the less the color fading: ). The first stage of exposure was set to 5 hours of continuous direct sunlight in winter and the second stage was set to 15 hours.
First exposure stage Second exposure stage JIS Blue Scale Level 15 23
. 〃 Level 2 11 18
.級 Grade 3 6 10
.級 Level 4-2
Kangaro petal pigmented cloth 7 13
Same as above, re-dyed cloth after cobalt salt treatment 4 7
Same as above, re-dyed after nickel salt treatment 4 7
Same as above, re-dyed after treatment with manganese salt 4 6

  The fastness to sunlight of a dyed cloth soaked with a koji petal pigment extract according to the method of the present invention is usually determined to be about 2 to 3 grades, but when treated with a salt such as cobalt, nickel, manganese, etc., it is grade 3 From the above, it can be seen that the color fastness is improved.

In addition, the color difference ΔE obtained by comparing the dyeing of red plant pigments, which have been practically used for a long time, with safflower and suou, and the sun resistance in the first stage of exposure was as follows.
Kangaro petal dyed cloth, re-dyed cloth after cobalt salt treatment 3
Same as above, re-dyed after nickel salt treatment 3
Same as above, re-dyed fabric after manganese salt treatment 3
Safflower dyeing 12
Suo dyeing (aluminum salt mordanting) 5
. 〃 (copper salt mordanting) 2

In the dyeing method according to the present invention, it was confirmed that ΔE is approximately halfway between the aluminum salt mordanting and the copper salt mordanting, and a practical dyeing cloth having better sunlight resistance than safflower dyeing can be obtained. .
Similar results were obtained when the same method as in Example 1 was performed using petals of red sasanqua instead of petals of kansui.

[Example 2]
The extract product of Murasaki potato pigment (produced by Taisho Laboratories: color value 800 units) containing a large amount of cyanidin and anthocyanin, a glycoside of peonidin, is a 4% aqueous solution, so that maleic acid is 0.5%. In addition, this liquid was prepared 25 to 50 times the weight of the silk cloth, and the following was used to dye the silk cloth in the same manner as in Example 1 to obtain a red rosy colored dyed cloth.

[Example 3]
A red morning glory petal (containing a large amount of anthocyanin containing pelargonidin glycoside as a main component) was immersed in a 0.5% maleic acid aqueous solution of about 5 times by weight at room temperature for one day or more to extract a pigment. The extract endured storage for 2 years in a refrigerator at 5 ° C.
The silk cloth is immersed in this extract (25-50 times the weight of the silk cloth by weight) at room temperature for one day and night, salt is added to make a 0.5% solution, and further immersed at room temperature for one day and night. Washed with water. Thereafter, the dyed fabric was treated with an aqueous solution of any one of cobalt, nickel, and manganese in the same manner as in Example 1, washed with water, further immersed in the dyeing residual solution for two days and nights, re-dyed and washed with water. The dyed fabric after the re-dyeing exhibited a vivid ruby red color peculiar to pelargonidin.

When the fastness to sunlight of this dyed fabric was examined by the same method as in Example 1, the color difference ΔE before and after exposure was as follows.
. First exposure stage Second exposure stage JIS Blue Scale Level 14 28
. 〃 Grade 2 9 20
.級 Grade 3 6 14
.級 Level 4-3
Red morning glory petal pigmented cloth 3 9
Same as above, re-dyed cloth after cobalt salt treatment 2 5
Same as above, re-dyed after nickel salt treatment 3 6
Same as above, re-dyed fabric after manganese salt treatment 2 6

  The fastness to sunlight of a dyed cloth soaked with a red morning glory petal extract according to the method of the present invention is determined to be 3 to 4 grades. The dyed fabric treated with a salt of cobalt, nickel, manganese, etc. and re-dyed also had the same fastness rating but a smaller ΔE and showed a tendency to improve sunlight resistance.

[Example 4]
Red shiso leaves containing a large amount of anthocyanin called shisonin, a cyanidin glycoside, were collected, and the leaves were immersed in a 0.5% maleic acid aqueous solution of the same weight at room temperature for one day or more to extract the pigment. The extract endured storage for 2 years in a refrigerator at 5 ° C. Moreover, silk cloth was dye | stained by the method similar to Example 1 using this extract. As a result, a fresh wine-red dyed silk cloth was obtained.

Claims (2)

  A dye solution having excellent storage stability, characterized in that an anthocyanin dye is contained in an aqueous solution containing maleic acid and having a pH of 1.2 or lower.   After dyeing the protein substance with a dye solution containing an anthocyanin dye in an aqueous solution containing maleic acid and having a pH of 1.2 or less, the dyed product is treated with a metal salt selected from the group consisting of cobalt, nickel and manganese. A method for staining a protein substance, comprising: