JP7780787B2 - Dye composition and method for producing dyed goods using said dye composition - Google Patents

Description

The present invention relates to a dye composition, particularly a dyeing composition containing plant dyes (some of which are insect dyes). The present invention also relates to a method for producing dyed articles using the dye composition.

With the growing trend towards natural products, plant dyes have been attracting attention, and plant-dyed prints have become popular. However, dyeability varies depending on the type of plant dye and the fiber being dyed. To solve this problem, for example, Patent Document 1 listed below discloses the use of chemical dyes in combination to improve fastness and obtain stable colors.
Furthermore, in the case of plant dyes, the direct dyeing ability of the dye is low depending on the material to be dyed, such as cellulose fibers. Therefore, in order to improve dyeing ability, a pretreatment process using a cationizing agent such as a cationic polymer or a quaternary ammonium salt is carried out to increase the adsorption efficiency of the dye and mordant in the printing process, thereby striving to achieve deep dyeing. For example, Patent Document 2 listed below proposes pretreatment with a plant dye adsorption aid, which is a cationic compound such as a quaternary ammonium salt.

However, when producing printed (dyed) items, this conventional method can cause staining by the dye that comes off along with the sizing agent during post-treatment soaping, which can be redeposited by the plant dye adsorption aid, resulting in the problem of white spot staining during the washing process.

Furthermore, in the case of conventional dyeing methods that have been used up until now, the dyeability of natural dyes varies depending on the material being dyed, and any dye that does not absorb is discharged into the drainage system together with the mordant and printing paste by soaping, which places a heavy burden on the drainage system throughout the entire process. For this reason, in order to reduce the drainage load, there is a demand for printing methods that do not use printing paste, and there is also a demand for methods that can dye deeply and efficiently.
Furthermore, there is a need for dyeing methods that can efficiently achieve deep dyeing with plant dyes for various fibers other than cellulose fibers, and there is also a general misconception that all plant dyes have medicinal effects, so this is also something that needs to be taken into consideration.

Patent No. 5791955 Patent No. 3779287

The present invention aims to provide a dyeing composition that does not require a pretreatment step for improving dyeability, and that can absorb plant dyes and mordants without leaving any residue and dye fibers.
Another object of the present invention is to provide a method for producing dyed products by printing natural or synthetic fibers with such a dyeing composition.

After extensive research, the inventors discovered that instead of the conventionally used printing pastes for plant dyeing (anionic or nonionic water-soluble printing pastes), chitosan, a naturally occurring polymer obtained from crab shells and other sources, is dissolved in an acid (preferably an organic acid), and then a polyurethane resin is added as a binder resin to prepare a printing binder in order to overcome the drawbacks of chitosan's hard coating and low solubility. They then prepared a dyeing composition by adding a thickener, if necessary, to adjust the viscosity. They discovered that by using the dyeing composition thus obtained, it is possible to eliminate the pretreatment step for improving the dyeability of fibers such as cellulose fibers, and to enable the plant dye and mordant to be fully absorbed and dyed into the fibers, thereby completing the present invention.

The dye composition of the present invention, which can be used to print natural fibers and synthetic fibers using a complex dye composition obtained using only naturally occurring dyes and a mordant, comprises the following components A to C:
Component A: a dye of natural origin,
Component B: a printing binder containing an acid, chitosan, a urethane resin, and mineral spirits;
Component C: a mordant,
The compound is characterized by containing

The present invention also provides a dye composition having the above characteristics, characterized in that the naturally derived dye is a liquid dye product of plant dyes and/or pigment components extracted from insects.

The present invention also provides a dye composition having the above characteristics, characterized in that the mordant is a mordant solution containing a salt of a metal selected from the group consisting of aluminum, titanium, and iron.

The present invention also provides a dye composition having the above characteristics, wherein the acid is selected from the group consisting of hydrochloric acid, nitric acid, formic acid, acetic acid, and propionic acid.

Furthermore, the present invention is also characterized in that, in the dye composition having the above characteristics, the acid content is 2.4 to 6.4 parts by weight, the chitosan content is 2.4 to 6.4 parts by weight, the urethane resin content is 3.2 to 8.0 parts by weight (solids content), and the mineral spirit content is 4 to 20 parts by weight, per 100 parts by weight of the dye composition.

The dye composition of the present invention is
Component A: Indian indigo,
Component B: a printing binder containing an acid, chitosan, a urethane resin, and mineral spirits;
The proportions of each component contained in component B are the same as those described above.

The present invention also provides a method for producing a dyed product using the dye composition, the method comprising the following steps I to III:
Step I: a step of dissolving 3 to 8 parts by weight of chitosan in 3 to 8 parts by weight of acid, adding 4 to 10 parts by weight (in terms of solid content) of urethane resin, 5 to 25 parts by weight of mineral spirits, and water in an amount that makes the total solution 100 parts by weight, and stirring the mixture to prepare a binder for textile printing;
Step II: adding 0.6 to 15 parts by weight of a naturally-derived dye solution to 70 to 85 parts by weight of the printing binder obtained in Step I, stirring, then adding 1 to 3 parts by weight (solid content equivalent) of a mordant, and adding water in an amount that makes the total solution 100 parts by weight, followed by stirring, to prepare a dye composition; and Step III: applying the dye composition obtained in Step II to a fiber to be dyed, thereby carrying out printing, and then carrying out a drying step and a steaming step to develop the color, thereby obtaining a dyed product.

The present invention is also characterized in that the acid used in step I of the method for producing a dyed product having the above characteristics is selected from the group consisting of hydrochloric acid, nitric acid, formic acid, acetic acid, and propionic acid.

The present invention is also characterized in that the fibers printed in step III of the method for producing a dyed product having the above characteristics are selected from the group consisting of cellulose fibers, protein fibers, and synthetic fibers.

The present invention also provides a method for producing a dyed product using Indian indigo, the method comprising the following steps I to III:
Step I: a step of dissolving 3 to 8 parts by weight of chitosan in 3 to 8 parts by weight of acid, adding 4 to 10 parts by weight (in terms of solid content) of urethane resin, 5 to 25 parts by weight of mineral spirits, and water in an amount that makes the total solution 100 parts by weight, and stirring the mixture to prepare a binder for textile printing;
Step II: adding 0.6 to 15 parts by weight of an Indian indigo-containing dye solution to 70 to 85 parts by weight of the printing binder obtained in Step I, stirring, and then adding water in an amount that makes the total solution 100 parts by weight and stirring again to prepare a dye composition; and Step III: applying the dye composition obtained in Step II to a fiber to be dyed to perform printing, followed by drying and steaming to develop the color and obtain a dyed product.

By using the dye composition of the present invention, the series of printing steps from pretreatment to soaping can be simplified without particularly deteriorating the color fastness in current plant dyeing, and by eliminating soaping, the wastewater load can be reduced.
In addition, at the same time as dyeing with plant dyes, it is possible to impart chitosan-derived antibacterial and antiviral properties to various fibers.

Components A to C contained in the dye composition of the present invention will now be described.
As the naturally derived dye, which is component A, a wide variety of plant dyes known to contain mordant pigments and liquid dyes of pigment components extracted from insects can be used, and for example, products commercially available from Tanaka Direct Dye Store Co., Ltd. can be used. Specific examples include, but are not limited to, sophora japonica (tragonathus) liquid, scutellaria baicalensis liquid, walnut liquid, catechu liquid, lac dye liquid, logwood liquid, and indigo liquid. The solids concentration in the dye solution of commercially available plant dyes varies depending on the type of plant dye. A mordant is not required for printing using indigo alone.
The content of Component A (naturally-derived dye) in 100 parts by weight of the dye composition of the present invention is preferably 0.1 to 7 parts by weight, particularly preferably 0.3 to 5 parts by weight. When the naturally-derived dye is Indian indigo only, the content of Indian indigo is preferably 0.6 to 9.6 parts by weight (as a paste product).

The printing binder (aqueous binder solution) of Component B contained in the dye composition of the present invention contains an acid, chitosan, a urethane resin, and mineral spirits, and the chitosan is contained as cationic chitosan produced by dissolving it in the presence of an acid (preferably an organic acid).
In the present invention, the acid for dissolving chitosan is preferably a volatile acid such as hydrochloric acid, nitric acid, formic acid, acetic acid, or propionic acid in order to prevent re-dissolution, and among these, acetic acid is particularly preferred from the viewpoints of safety and volatility.
The content of the acid in 100 parts by weight of the dye composition of the present invention is 2.4 to 6.4 parts by weight, preferably 3.2 to 5.0 parts by weight, and the content of chitosan is 2.4 to 6.4 parts by weight, preferably 2.4 to 4.8 parts by weight.

In addition, in the present invention, by incorporating a urethane resin into the printing binder, the viscosity of the dye composition can be increased, and the coating formed on the surface of the fiber to be dyed can be made flexible, improving the texture and reducing tackiness of the coating. In the present invention, such a urethane resin is preferably incorporated in the form of a water-soluble emulsion.
As the urethane resin suitable for the present invention, a polyurethane resin based on polyester polyol is particularly preferred from the viewpoints of hydrolysis resistance, stability, and weather resistance.
In the present invention, a nonionic blocked isocyanate crosslinking agent may be used in combination to improve the fastness of the urethane resin.
The content of the urethane resin in 100 parts by weight of the dye composition of the present invention is 3.2 to 8.0 parts by weight, preferably 4.0 to 5.6 parts by weight, calculated as solid content. When the crosslinking agent is used in combination with the urethane resin, the content of the crosslinking agent is 0.8 to 4.0 parts by weight, preferably 1.6 to 2.4 parts by weight.

In addition to the above components, the dye composition of the present invention contains mineral spirits, a non-polar solvent, to achieve a viscosity suitable for textile printing, since chitosan dissolved in an acid (preferably acetic acid) has a high viscosity and is not suitable for textile printing. The content of mineral spirits in 100 parts by weight of the dye composition of the present invention is 4 to 20 parts by weight, preferably 5 to 17 parts by weight.
Furthermore, in the present invention, it is preferable to emulsify a highly viscous liquid obtained by dissolving chitosan in acid by blending mineral spirits with the liquid and then adding a viscosity modifier. After adjusting the viscosity by adding the viscosity modifier, the urethane resin can be added to obtain a viscosity suitable for use as a binder for textile printing.

Preferred viscosity modifiers in the present invention include nonionic ether-type cellulose derivatives, nonionic ether-ester-type starches, nonionic locust bean gum, tamarind guar gum, cationic guar gum, cationic starches, and cationic cellulose derivatives.
In the present invention, naturally processed thickeners and nonionic surfactants with high HLB values and chemical resistance can be used as viscosity modifiers, and nonionic surfactants with high HLB values are preferred from the viewpoint of film flexibility and thickening properties. The content of the viscosity modifier per 100 parts by weight of the dye composition of the present invention is 0.8 to 2.4 parts by weight, preferably 1.2 to 2.0 parts by weight.

In the present invention, the addition of a sequestering agent is preferable because mixing the chitosan in the printing binder with the metal ions of the natural dye and mordant forms an insoluble complex, making the composition unstable. The sequestering ability of the agent temporarily chelates the metal ions of the mordant, stabilizing the chitosan binder. The dry heat in the drying step and the steaming heat in the steaming step volatilize the sequestering agent together with the acid, completing the formation of a chitosan-containing coating and the complexation of the natural dye. The content of the sequestering agent per 100 parts by weight of the dye composition of the present invention is 2.4 to 4.8 parts by weight, preferably 3.0 to 4.0 parts by weight. Acetylacetone is a preferred sequestering agent.
Furthermore, in the present invention, it is preferable to incorporate a moisture absorbent in the printing binder in order to improve color development, and the moisture absorption and delayed action of the moisture absorbent allows for uniform film formation and steaming effects. The content of the moisture absorbent in 100 parts by weight of the dye composition of the present invention is 4.8 to 9.6 parts by weight, preferably 6.4 to 8.0 parts by weight, and preferred examples of the moisture absorbent include ethylene glycol, propylene glycol, and polyethylene glycol.

Furthermore, the mordant of component C in the dye composition of the present invention is a component necessary for forming a complex with the plant dye, and it is also necessary for various hues (colors) to be expressed depending on the combination. However, taking into consideration sewage treatment and the like, it is preferable to blend a mordant solution containing a salt of a metal selected from the group consisting of aluminum, titanium, and iron.
In the present invention, a wide range of known mordants for plant dyes can be used, and by appropriately selecting the type of mordant, it is possible to dye the fiber to the desired color. The content of the mordant in 100 parts by weight of the dye composition of the present invention is preferably 0.1 to 3 parts by weight (solids equivalent). However, when indigo alone is used as the plant dye, the mordant (component C) is not necessary.

The dye composition of the present invention, which is an aqueous emulsion containing a urethane resin, contains each component in a proportion within the ranges described above, with the remainder consisting mainly of water or water alone.

Next, each step in the method of the present invention for producing dyed goods using the dye composition will be described.
In step I of the production method of the present invention, a printing binder is prepared by dissolving 3 to 8 parts by weight of chitosan in 3 to 8 parts by weight of acid, adding 4 to 10 parts by weight (in terms of solids content) of urethane resin, 5 to 25 parts by weight of mineral spirits, and an amount of water to make the total solution 100 parts by weight to the resulting chitosan solution, and stirring the mixture. In this process, a commercially available chitosan (powder) can be used, the acid is preferably selected from the group consisting of hydrochloric acid, nitric acid, formic acid, acetic acid, and propionic acid, and the urethane resin can be a commercially available aqueous urethane resin (a material in which polyurethane resin is dispersed in water).

In step II of the production method of the present invention, 0.6 to 15 parts by weight of a dye solution containing a naturally-derived dye (naturally-derived dye solution) is added to 70 to 85 parts by weight of the printing binder obtained in step I, and after stirring, 1 to 15 parts by weight of a mordant is added, and water is added in an amount that makes the total solution 100 parts by weight, and the mixture is stirred to prepare a dye composition. In this case, the naturally-derived dye solution and mordant used are those described above.
In the present invention, the naturally occurring dye solution may be in a paste form in addition to a liquid form.

In step III of the production method of the present invention, the dye composition prepared in step II is applied to a fiber to be dyed to perform printing, followed by drying and steaming steps to develop the color and obtain a dyed product. When the dye composition of the present invention is used, the printing binder is fixed on the fiber after printing, and the water-soluble emulsion is converted into a water-insoluble solid by the steaming step. Therefore, in the production method of the present invention, no post-treatment or soaping is particularly required, and even if a post-process is performed, only a water washing step to remove impurities is required.
The conditions for the drying step in step III are preferably 120 to 150°C for about 1 to 3 minutes, and the conditions for the steaming step are preferably 95 to 110°C for about 10 to 30 minutes.

In the production method of the present invention, the fibers of the dyed object to which the dye composition is applied in the above-mentioned step III are not limited to cellulose fibers such as cotton and hemp, or protein fibers such as wool and silk, which are generally used for plant dyeing, but also include synthetic fibers such as polyester fibers and polyamide fibers (nylon fibers), which are generally not dyed with plant dyes, and so long as they can be adhered with the above-mentioned printing binder, they can be printed using plant dyes.
In the present invention, the method for applying the dye composition to the material to be dyed is not particularly limited, but it is preferable to use a screen printing machine such as a flat screen or rotary screen, or a roller printing machine.

When the method for producing dyed products of the present invention is used, naturally derived dyes can be developed and fixed on the fibers to be dyed without particularly reducing the color fastness of current plant dye dyes, and the dyes can be fixed together with the printing binder, thereby simplifying the entire printing process from pretreatment to soaping.
Furthermore, in the dyed products printed with the plant dyes by using the production method of the present invention, the plant dyes are fixed on the fibers together with the printing binder, and therefore not only can the color development unique to the plant dyes be observed, but also the products have the antibacterial and antiviral properties derived from chitosan.

Example 1
Acetic acid was prepared as an organic acid, and 4 parts by weight of commercially available chitosan (powder) was dispersed in a small amount of warm water. The dispersion was added to 6 parts by weight of acetic acid and stirred to prepare a chitosan solution. To this chitosan solution, 20 parts by weight of a water-soluble emulsion containing a polyurethane resin based on polyester polyol (manufactured by Murayama Chemical Laboratory Co., Ltd., product name: Simplex PUE-C200B, solids concentration: 30%) and 20 parts by weight of mineral spirits were added, and further 4 parts by weight of acetylacetone was added as a sequestering agent. The mixture was stirred, and water was added to make up the total amount to 100 parts by weight, thereby preparing a binder for textile printing.
Then, a commercially available plant dye, a sophora japonica extract (solid content concentration: 25%), was prepared as a naturally derived dye solution, and 5 parts by weight of this sophora japonica extract was added to 80 parts by weight of the above-prepared binder for textile printing, and the mixture was thoroughly stirred. Then, 5 parts by weight of an aluminum mordant (10% aluminum acetate solution) and 2 parts by weight of a blocked isocyanate crosslinking agent (manufactured by Murayama Chemical Laboratory Co., Ltd., trade name: Fixer #220) diluted with water were added, and the total solution was adjusted to 100 parts by weight, and the mixture was thoroughly stirred to prepare a dyeing composition of the present invention.
A 60/2 cotton lawn was prepared as a dyed article, and the dyeing composition obtained above was applied to this 60/2 cotton lawn to perform printing (textile printing process), followed by drying at 140°C for 2 minutes, a steaming process at 103°C for 20 minutes in a continuous steamer, and then a water-washing process to obtain a dyed article.
The dyed products obtained using the above method did not show any bleeding of the color, even though Sophora japonica, which has a weak waterfastness to begin with, and it was confirmed that the binder, the dyed product, and the plant dye were sufficiently fixed.

Example 2
Dyed products were produced in the same manner as in Example 1, except that 9 parts by weight of ethylene glycol was further added when preparing the printing binder.
The dyed product thus obtained had better color development than the composition obtained in Example 1, and the chitosan-containing coating was uniform.

Example 3
As a naturally derived dye solution, a commercially available botanical dye, Scutellaria extract (solid content: 50%), was prepared, and a dyeing composition of the present invention was prepared using 5 parts by weight of this Scutellaria extract in the same manner as in Example 2 above.
The dyeing composition was applied to the same 60/2 cotton lawn as in Example 1 above, and printing was carried out in the same manner as in Example 1 above, followed by a drying step (140°C x 2 minutes) and a steaming step (103°C x 20 minutes), and then a water-washing step, to obtain a dyed product.
The dyed products obtained using the above method were confirmed to have no bleeding of color and the plant dyes were fixed with sufficient fixing power.

Example 4
As a naturally derived dye solution, a commercially available plant dye, a walnut extract (solid content concentration: 50%), was prepared, and a dyeing composition was prepared in the same manner as in Example 2 using 5 parts by weight of this walnut extract. This dyeing composition was applied to a 60/2 cotton lawn, and then the same steps as in Example 1 were carried out to obtain a dyed product.
The dyed products obtained by the above method showed no bleeding of the color even when subjected to a washing step.

Example 5
As a naturally derived dye solution, a commercially available plant dye, catechu extract (solid content: 25%), was prepared, and a dyeing composition was prepared using 5 parts by weight of this catechu extract in the same manner as in Example 2 above.This dyeing composition was then applied to a 60/2 cotton lawn, and the same process as in Example 1 was carried out to obtain a dyed product.
The dyed products obtained by the above method did not lose their color even after washing.

Example 6
A lac dye extract (solid content concentration: 10%), which is a commercially available plant dye, was prepared as a naturally derived dye solution. Using 5 parts by weight of this lac dye extract, a dyeing composition was prepared in the same manner as in Example 2 above. This dyeing composition was applied to a 60/2 cotton lawn, and then the same steps as in Example 1 were carried out to obtain a dyed product.
The dyed products obtained by the above method were found to have only slight loss of color even when washed with water, and were therefore of no practical use.

Example 7
A logwood extract (solid content: 67%), which is a commercially available plant dye, was prepared as a naturally derived dye solution. Using 5 parts by weight of this logwood extract and 5 parts by weight of an iron mordant (4.5% iron pyroacetate solution) as a mordant, a dyeing composition was prepared in the same manner as in Example 2 above. This dyeing composition was applied to a 60/2 cotton lawn, and then the same steps as in Example 1 were carried out to obtain a dyed product.
When the dyed product obtained by the above method was subjected to a washing step, no coloration of the wastewater was observed.

Example 8
As a naturally derived dye solution, a paste of Indian indigo (commonly known as indigo), a commercially available plant dye (manufactured by Tanaka Direct Dye Store Co., Ltd., product name: purified Indian indigo paste), and the sophora japonica extract used in Example 1 were prepared, and 0.5 parts by weight of the Indian indigo paste and 4.5 parts by weight of the sophora japonica extract were mixed together to prepare a dyeing composition in the same manner as in Example 2 above.This dyeing composition was applied to a 60/2 cotton lawn, and then the same steps as in Example 1 were carried out to obtain a dyed product.
In the case of dyed products obtained using the above method, even in green colors, which are said to be difficult to achieve with plant dyes, only slight color transfer occurred and there was almost no color loss, even with post-treatment consisting only of a water washing step. It was also confirmed that the dyed products met the washing fastness test of the A-1 method of JIS-L-0844.

Example 9
As a naturally derived dye solution, a paste product (5 parts by weight) of Indian indigo (commonly known as indigo) described in Example 8 was prepared, and a dyeing composition was prepared by stirring it with only the printing binder described in Example 2 without using a mordant (component C). This dyeing composition was then applied to a 60/2 cotton lawn, and the same steps as in Example 1 were carried out to obtain a dyed product.
When the dyed product obtained by the above method was subjected to a washing step, no coloration of the wastewater was observed.

In the following Comparative Examples 1 to 7, 60/2 cotton lawn was cationized using a commonly used quaternary ammonium salt cationizing agent and caustic alkali agent, and then printed with a commonly used printing paste using the plant dyes and mordants described in Examples 1 to 9 above. The resulting product was then dried under the same conditions as in Examples 1 to 9 above, steamed in a continuous steamer at 103°C for 20 minutes, and then washed with water to obtain a dyed product. The dyed product thus obtained was then compared with the dyed product obtained in the previous Examples.

Comparative Example 1
A printing paste composition was prepared by preparing an extract of Sophora japonica, a commercially available plant dye, as a naturally derived dye solution, preparing aluminum acetate as a mordant, and adding 55 parts by weight of a commercially available printing paste (manufactured by Yoshikawa Chemical Industry Co., Ltd., product name: ND-20) and water in the same amounts as in Example 1 to make 100 parts by weight and stirring. Thereafter, this printing paste composition was used to print 60/2 cotton lawn in the same manner as in Example 1, followed by a steaming step (103°C x 20 minutes) and a desizing treatment by desizing soaping (60 to 70°C x 10 minutes), to obtain a dyed product.
The dyed products obtained using the above method had soaping stains on the white areas, and the color strength was clearly 20 to 30% lighter than when a printing binder was used.

Comparative Example 2
A walnut extract solution, a commercially available plant dye, was prepared as a naturally derived dye solution, and aluminum acetate was prepared as a mordant. The same amounts as in Example 4 of a commercially available printing paste (the same as in Comparative Example 1) and water were added to make 100 parts by weight, and the mixture was stirred to prepare a printing paste composition. Thereafter, this printing paste composition was used to print 60/2 cotton lawn in the same manner as in Comparative Example 1, followed by a steaming step and a desizing treatment with desizing soaping, to obtain a dyed product.
In the case of the above method, when the wastewater was observed after the desizing soaping, it was found that the wastewater was only slightly contaminated, but the color depth of the dyed product obtained was lighter than when a printing binder was used.

Comparative Example 3
A commercially available botanical dye, Scutellaria extract, was prepared as a naturally derived dye solution, and aluminum acetate was prepared as a mordant. The same amounts as in Example 3 of commercially available printing paste (the same as in Comparative Example 1) and water were added to make 100 parts by weight, and the mixture was stirred to prepare a printing paste composition. Thereafter, this printing paste composition was used to print 60/2 cotton lawn in the same manner as in Comparative Example 1, followed by a steaming step and a desizing treatment with desizing soaping, to obtain a dyed product.
In the case of the above method, when the wastewater was observed after the desizing soaping, it was found that the wastewater was only slightly contaminated, but the color depth of the dyed product obtained was lighter than when a printing binder was used.
The dyed products obtained as described above had a color strength about 30% lighter than those obtained using a printing binder, and the dye came off together with the sizing agent, resulting in coloration of the wastewater.

Comparative Example 4
A commercially available plant dye, catechu extract, was prepared as a naturally derived dye solution, and aluminum acetate was prepared as a mordant. The same amounts as in Example 5 of commercially available printing paste (the same as in Comparative Example 1) and water were added to make up 100 parts by weight, and the mixture was stirred to prepare a printing paste composition. Thereafter, this printing paste composition was used to print 60/2 cotton lawn in the same manner as in Comparative Example 1, followed by a steaming step and a desizing treatment with desizing soaping, to obtain a dyed product.
In the case of the above method, the color of the wastewater after desizing soaping was not deep, but the color strength (dyeing concentration) of the obtained dyed product seemed to be about 30% lighter than the color strength when printing was carried out using a printing binder.

Comparative Example 5
A lac dye extract, a commercially available plant dye, was prepared as a naturally derived dye solution, and aluminum acetate was prepared as a mordant. The same amounts as in Example 6 of commercially available printing paste (the same as in Comparative Example 1) and water were added to make up 100 parts by weight, and the mixture was stirred to prepare a printing paste composition. Thereafter, using this printing paste composition, 60/2 cotton lawn was printed in the same manner as in Comparative Example 1, followed by a steaming step and a desizing treatment with desizing soaping, to obtain a dyed product.
In the case of dyed products obtained using the above method, when desizing soaping was carried out after the steaming step, the white areas of the cotton fabric were more stained than when a printing binder was used, and the color strength was about 30% lighter.

Comparative Example 6
A logwood extract, a commercially available plant dye, was prepared as a naturally derived dye solution, and ferric pyroacetate was prepared as a mordant. The same amounts as in Example 7 of a commercially available printing paste (the same as in Comparative Example 1) and water were added to make 100 parts by weight, and the mixture was stirred to prepare a printing paste composition. Thereafter, this printing paste composition was used to print 60/2 cotton lawn in the same manner as in Comparative Example 1, followed by a steaming step and a desizing treatment with desizing soaping, to obtain a dyed product.
The color strength of the dyed product obtained by the above method was about 30% lighter than that obtained by using a printing binder, and considerable staining was observed.

Comparative Example 7
As the naturally derived dye solution, commercially available plant dyes, Indian indigo paste and Sophora japonica extract (same as in Example 8), were prepared, and an aluminum acetate mordant was prepared. A blend of this Indian indigo paste, Sophora japonica extract, and mordant was added to a commercially available printing paste (same as in Comparative Example 1) and stirred to prepare a printing paste composition. This printing paste composition was then used to carry out the same process as in Comparative Example 1, to obtain a dyed product. In Comparative Example 7, Indian indigo has substantivity, and the fabric was specifically subjected to cationization treatment for the Sophora japonica extract, and 60/2 cotton lawn was used as the substrate to be dyed.
In the case of the dyed products obtained using the above method, considerable staining was observed on the white areas, much of the dye was removed, and spots were also observed in the dyed color.

In all of the above Comparative Examples 1 to 7, after rinsing, the dyed products were subjected to the commonly used soaping method (60-70°C x 10 minutes). When the dyed products were inspected after drying, it was found that the white areas had been stained with the color of the remaining soaping liquid, and the color intensity of the plant dye was clearly 30-40% lower than in Examples 1 to 9.

Furthermore, #50 polyester satin was prepared as the substrate and the dyeing compositions described in each example were used to carry out processing tests similar to those for cotton lawn. Although a slight decrease in density was observed, this was thought to be due to differences in the amount of binder applied depending on the substrate, and it was confirmed that dye density was equivalent to that of cotton lawn. The experiment using #50 polyester satin proved that printing with plant dyes and mordants is possible even on synthetic fibers when using the dyeing compositions of the present invention.

As described above, when the dyeing composition of the present invention containing a printing binder containing chitosan is used, a pretreatment step for improving dyeability is not required, and the plant dye and the mordant can be absorbed without any waste and dyed into the fiber, so the method for producing a dyed product of the present invention using the dyeing composition is excellent as a printing method.
Furthermore, a chitosan-containing binder can be used for all plant dyes, and the chitosan-containing binder is fixed on the surface of the fiber after printing. Therefore, by using the method for producing a dyed product of the present invention, it is possible to impart an antibacterial effect to fibers printed with naturally derived dyes of various colors.
The representative color printed portions of the dyed products obtained in Examples 1 to 9 were subjected to an antibacterial test using Staphylococcus aureus according to the JIS-L-1902 bacterial liquid absorption method, and the results showed that all of the dyed products had antibacterial properties.

The dye composition of the present invention comprises
1) It can contribute to labor-saving in the printing process using plant dyes.
2) Printing using a chitosan-containing binder reduces waste of plant dyes and mordants.
3) No soaping is required, reducing drainage load.
4) It can impart antibacterial effects to the printed part.
These advantages make it possible to print both natural and synthetic fibers, and it can be said that the method is highly applicable industrially.

Claims (10)

Component A: a dye of natural origin,
Component B: a printing binder containing an acid, chitosan, a urethane resin, and mineral spirits;
Component C: a mordant,
A dye composition comprising: The dye composition according to claim 1, wherein the naturally derived dye is a liquid dye product of plant dyes and/or pigment components extracted from insects. The dye composition according to claim 1 or 2, wherein the mordant is a mordant solution containing a salt of a metal selected from the group consisting of aluminum, titanium, and iron. The dye composition according to any one of claims 1 to 3, wherein the acid is selected from the group consisting of hydrochloric acid, nitric acid, formic acid, acetic acid, and propionic acid. The dye composition according to any one of claims 1 to 4, characterized in that, per 100 parts by weight of the dye composition, the acid content is 2.4 to 6.4 parts by weight, the chitosan content is 2.4 to 6.4 parts by weight, the urethane resin content is 3.2 to 8.0 parts by weight (solids content equivalent), and the mineral spirit content is 4 to 20 parts by weight. Component A: Indian indigo,
Component B: a printing binder containing an acid, chitosan, a urethane resin, and mineral spirits;
A dye composition comprising: The following steps I to III:
Step I: a step of dissolving 3 to 8 parts by weight of chitosan in 3 to 8 parts by weight of acid, adding 4 to 10 parts by weight (in terms of solid content) of urethane resin, 5 to 25 parts by weight of mineral spirits, and water in an amount that makes the total solution 100 parts by weight, and stirring the mixture to prepare a binder for textile printing;
Step II: adding 0.6 to 15 parts by weight of a naturally-derived dye solution to 70 to 85 parts by weight of the printing binder obtained in Step I, stirring the mixture, and then adding 0.1 to 3 parts by weight (solid content equivalent) of a mordant, and then adding water in an amount that makes the total solution 100 parts by weight, and stirring the mixture to prepare a dye composition; and Step III: applying the dye composition obtained in Step II to a fiber to be dyed, thereby carrying out printing, and then carrying out a steaming step to develop the color, thereby obtaining a dyed product. The method for producing a dyed product according to claim 7, wherein the acid is selected from the group consisting of hydrochloric acid, nitric acid, formic acid, acetic acid, and propionic acid. The method for producing a dyed product according to claim 7 or 8, wherein the fibers printed in step III are selected from the group consisting of cellulose fibers, protein fibers, and synthetic fibers. The following steps I to III:
Step I: a step of dissolving 3 to 8 parts by weight of chitosan in warm water and 3 to 8 parts by weight of acid, adding 4 to 10 parts by weight (in terms of solid content) of urethane resin, 5 to 25 parts by weight of mineral spirits, and water in an amount that makes the total solution 100 parts by weight, and stirring the mixture to prepare a binder for textile printing;
Step II: adding 0.6 to 15 parts by weight of an Indian indigo-containing dye solution to 70 to 85 parts by weight of the printing binder obtained in Step I, stirring, and then adding water in an amount that makes the total solution 100 parts by weight and stirring again to prepare a dye composition; and Step III: applying the dye composition obtained in Step II to a fiber to be dyed to perform printing, and then performing a drying step and a steaming step to develop the color and obtain a dyed product.