Combined dyeing process

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Application No. 10-2014-0030158, filed on Mar. 14, 2014, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a combined dyeing method, and more particularly, to a combined dyeing method that reduces side effects of a conventional chemical dyeing method and also overcomes shortcomings of a conventional eco-friendly dyeing method.

2. Description of the Related Art

A conventional chemical dyeing method is a method for extracting dyes having various properties and colors from a petroleum compound through artificial processes and dyeing clothes, and is carried out through {circle around (1)} a desizing process, {circle around (2)} a scouring process, {circle around (3)} a bleaching process, {circle around (4)} a dyeing process, {circle around (5)} a cleaning process, and {circle around (6)} a drying process.

The desizing process is a process for removing a thickening agent added to fabric while the fabric is manufactured, and examples of the thickening agent may include starch, gelatin, glue, etc.

The scouring process is a process of removing impurities (natural impurities such as wax, pectin, and ash, and a thickening agent and emulsion added during a spinning process and a weaving process) from fiber. As a scouring agent, an inorganic scouring agent, a surfactant, a detergent, a solvent, and a degreaser may be used.

The bleaching process is a process of decomposing and removing pigments present in fiber with an oxidizing agent or a reducing agent. An example of the oxidizing agent used in the bleaching process may include an oxidation bleacher and an example of the reducing agent may include a reduction bleacher. Examples of the oxidation bleacher may include peroxide-based bleachers such as hydrogen peroxide (H₂O₂), potassium permanganate (KMnO₄), sodium percarbonate (2Na₂CO₃.3H₂O₂), etc. and chloride-based bleachers such as bleaching powder (Ca(OCl)₂), sodium hypochlorite (NaOCl), etc., and examples of the reduction bleacher may include hydrosulfite (Na₂S₂O₄), sodium hydrogensulfite (NaHSO₃), etc. Further, a bleaching method and a bleacher to be used may vary depending on properties of each fiber. The above-described desizing, scouring process, and bleaching process are referred to as pre-treatment processes.

The fiber undergoing the pre-treatment processes is subjected to the dyeing process in which the fiber is dyed with a chemical dye. The chemical dye is prepared by adding toxic chemicals to a petroleum compound (benzene) or the like, and, thus, toxic substances are discharged during a process for producing the chemical dye.

The dyeing process is a process of dyeing fiber with a chemical dye or the like. A kind and a method of dyeing may include a direct dyeing method, a mordant dyeing method, a reduction dyeing method, an azo dyeing method, a disperse dyeing method, etc.

The direct dyeing method refers to a method of dissolving a water-soluble dye such as a direct dye, an alkaline dye, and an acid dye in water and dyeing fiber with the dye by heating, and it is the simplest method of directly dyeing fiber without mordanting. These dyes are water-soluble, and, thus, they are likely to come out of the fiber if washed and likely to be discolored by the sun. There is an example in which copper or chrome molecules are added to molecules of a direct dye for higher fastness.

The mordant dyeing method refers to a method of dyeing fiber with a dye using a mordant. That is, if a dye is dissolved in water but has low color and is difficult to firmly dye fiber, a mordant is used in combination with the dye to firmly dye the fiber so as to be insoluble in water. A representative example of the mordant dyeing is a madder dyeing method using alizarin.

The reduction dyeing method is a method of dyeing fiber with a dye such as indigo or indanthrene. A vat dye such as indigo or indanthrene and a sulfide dye are not dissolved in water and thus cannot be used as dyes as they are. However, if they are reduced to alkaline hydrosulfide or an aqueous solution of sodium sulfide, the dyes are dissolved and used to dye fiber. If the dyed fiber is left in the air, the dye is oxidized and returned to its original state and the dye turns into an insoluble dye in the fiber. Therefore, the dye is fast to washing and resistant to the sun in most cases, and, thus, it is highly practical.

The azo dyeing method is a method of synthesizing a pigment in fiber. In some of insoluble dyes, a pigment is decomposed after reduction but is not returned to its original state even if it is oxidized in the air. In this case, a pigment is synthesized in fiber by allowing intermediates of the pigment to be adsorbed in sequence into the fiber. Examples of the azo dyeing method may include aniline black dyeing or naphthol dyeing. Since the pigment is not dissolved in water, fastness to washing and fastness to light is high.

The disperse dyeing method is a method of dyeing synthetic fiber such as acetate, nylon, or polyester by dispersing and heating a dye, which is slightly soluble in water but easily soluble in alcohol and ester, in water and allowing the dye to be adsorbed into synthetic fiber. Since most synthetic fibers are hydrophobic, it is difficult to dye the synthetic fibers with water-soluble dyes. Thus, the disperse dyeing method is used. Polyester that is the most difficult to be dyed may be heated to 120° C. under pressure.

The above-described dyeing process is followed by the cleaning process of cleaning the dyed material and the drying process of the dyed material after cleaning, and, thus, the chemical dyeing is completed.

However, this chemical dyeing method causes environmental pollution since various toxic substances are added during production of dyes and during a dyeing process. In particular, while fiber is dyed with chemical dyes, various toxic auxiliaries for dyeing are added, and, thus, environmental pollutants are discharged. Further, when the dyed fiber is neutralized and washed, a lot of water is used. The water used at this time contains environmental pollutants such as toxic substances, and, thus, a lot of waste water is generated.

Further, recently, in the case of dyeing fabric so as to be expressed in various colors and vivid colors, the chemical dyeing method is carried out several times, resulting in worsening of environmental pollution and waste of water.

Furthermore, in the case of blue jeans chemically dyed with indigo, arylamine which is a toxic compound has been detected from some blue jeans. Therefore, if the chemical dyeing method is carried out several times to blue jeans to be dyed with indigo in order to achieve various colors, a washing effect, or vivid colors, a user may be exposed more times to such a toxic compound.

Recently, in order to overcome the side effects of the chemical dyeing method, a eco-friendly dyeing method using natural dyes has been developed. However, such a eco-friendly dyeing method is relatively high in production cost as compared with the chemical dyeing method, and is not adequate for expression of various colors. Further, in the eco-friendly dyeing method, brightness and chroma is low as compared with the chemical dyeing method, and the eco-friendly dyeing method is not adequate for mass production. Furthermore, in the eco-friendly dyeing method, fastness is low and a dye transfer rate is high.

Also, in the case of dyeing blue jeans by means of the eco-friendly dyeing method with natural indigo, it is a bit difficult to achieve various colors, a washing effect, or vivid colors.

Therefore, recently, when dyeing target materials including blue jeans are dyed in various colors, vivid colors, and impression of various colors as desired by users, there is a demand for development of a dyeing method that reduces side effects caused by carrying out a conventional chemical dyeing method several times and also overcomes shortcomings of a conventional eco-friendly dyeing method.

PRIOR ART DOCUMENT

Patent Document

Korean Patent Publication No. 2011-0039196

SUMMARY OF THE INVENTION

An object of the present invention is to provide a combined dyeing method that reduces side effects occurring in a conventional chemical dyeing method and also overcomes shortcomings occurring in a conventional eco-friendly dyeing method.

However, problems to be solved by the present invention are not limited to the above-described problems. Although not described herein, other problems to be solved by the present invention can be clearly understood by those skilled in the art from the following description.

According to an exemplary embodiment of the present invention, a combined dyeing method includes: a scouring process (S12) of scouring a dyeing target material which is chemically dyed with a chemical dye to remove impurities remaining in the dyeing target material; an eco-friendly dyeing process (S13) of dyeing the dyeing target material with an natural dye; a mordanting process (S14) of adding a mordant to the dyeing target material to fix the natural dye to the dyeing target material; a cleaning process (S15) of removing the mordant remaining in the dyeing target material; and a drying process (S16) of drying the dyeing target material.

Preferably, the mordant added in the mordanting process (S14) is one or more of quicklime, slaked lime, aluminum acetate, and aluminum chloride.

According to another exemplary embodiment of the present invention, a combined dyeing method includes: a scouring process (S22) of scouring a dyeing target material which is chemically dyed with an indigo-added chemical dye to remove impurities remaining in the dyeing target material; a reduction dyeing process (S23) of dyeing the dyeing target material by adding a dyeing solution to the dyeing target material; an oxidizing process (S24) of oxidizing the dyeing target material by exposing the dyeing target material to the air; a neutralizing process (S25) of neutralizing the dyeing target material by adding an acetate aqueous solution to the dyeing target material; a cleaning process (S26) of cleaning the dyeing target material; and a drying process (S27) of drying the dyeing target material.

Preferably, the dyeing solution is prepared by mixing 1 L of water, 1 to 10 g of natural indigo powder, 5 to 10 g of hydrosulfite, and 2 to 5 g of sodium hydroxide.

Preferably, the reduction dyeing process (S23) is carried out for 20 to 40 minutes while the dyeing solution is at a temperature ranging from 20 to 30° C.

Other details of the exemplary embodiments are included in the detailed description and the drawings.

The combined dyeing method according to the present invention has the following effects.

Firstly, after a chemical dyeing method is first carried out to a dyeing target material to obtain various and vivid colors and various effects such as artificial bleaching or vintage washing, the dyeing target material is dyed by an eco-friendly dyeing method to neutralize toxins which may be generated in the chemical dyeing method and express the impression of natural colors caused by natural dyes.

Secondly, spending of high production cost caused by dyeing the dyeing target material by the eco-friendly dyeing method only or inadequate expression of various colors can be overcome by carrying out the chemical dyeing method first and then carrying out the eco-friendly dyeing method, and various colors and satisfying fastness can be achieved by the eco-friendly dyeing method.

Thirdly, when blue jeans are dyed using indigo, the blue jeans are dyed by carrying out the chemical dyeing method first so as to express vivid colors and various effects, and then, the blue jeans are dyed by the eco-friendly dyeing method, and, thus, toxins expressed in the chemical dyeing method can be removed and the expression of natural colors caused by natural dyes can also be expressed.

Fourthly, if dyeing is carried out only by the eco-friendly dyeing method, it is possible to overcome a problem of excessive expense caused by carrying out the eco-friendly dyeing method several times to obtain colors and effects expressed by the chemical dyeing method.

Effects of the present invention are not limited to the above-described effects. Although not described herein, other effects can be clearly understood by those skilled in the art from the description of claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flowchart of a combined dyeing method according to an exemplary embodiment of the present invention.

FIG. 2 is a process flowchart of a combined dyeing method according to another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In explaining the present invention, well-known functions or constructions are not described in detail since they would obscure the present invention in unnecessary detail. It is noted that if the terms are expressed the same but intended differently, they are assigned different reference numerals.

Further, terms described below, which are defined considering functions in the present disclosure, can be different depending on user and operator's intention or practice. Therefore, the terms should be defined based on the disclosure throughout this specification.

In the present specification, the terms “first”, “second”, etc. may be used to explain various components, but the components shall not be limited to these terms. These terms are used only to distinguish one component from another component.

For example, within the scope of the present invention, a first component may be referred to as a second component and similarly, a second component may be referred to as a first component. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Any terms set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments. The singular forms include plural reference unless the context clearly dictates otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to those skilled in the art. It is noted that unless defined otherwise, the terms defined in usual dictionaries have the same meaning used in related technical documents and herein but are not understood as ideal meanings and very official meanings.

Further, the term “comprises or includes” and/or “comprising or including” used in the document means that one or more other components, steps, operation and/or existence or addition of elements are not excluded in addition to the described components, steps, operation and/or elements unless context dictates otherwise.

Hereinafter, illustrative embodiments will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals denote like parts.

FIG. 1 is a process flowchart of a combined dyeing method according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a combined dyeing method according to an exemplary embodiment of the present invention includes: a scouring process (S12) of scouring a dyeing target material which is chemically dyed with a chemical dye to remove impurities remaining in the dyeing target material; an eco-friendly dyeing process (S13) of dyeing the dyeing target material with an natural dye; a mordanting process (S14) of adding a mordant to the dyeing target material to fix the natural dye to the dyeing target material; a cleaning process (S15) of removing the mordant remaining in the dyeing target material; and a drying process (S16) of drying the dyeing target material.

A chemical dyeing process (S11) is a process of chemically dyeing a dyeing target material to be dyed with a chemical dye. The dyeing target material can be dyed by a conventional chemical dyeing method. The dyeing target material may include fiber, yarn, fabric, or the like, and preferably a plant material such as cotton.

The scouring process (S12) is a process of scouring the dyeing target material which is chemically dyed. The scouring process (S12) is a process of removing impurities including toxic substances remaining in the dyeing target material which is chemically dyed. In the scouring process (S12), the dyeing target material is immersed in water and boiled with addition of soap to remove impurities or toxic substances remaining in the dyeing target material.

The eco-friendly dyeing process (S13) is a process of dyeing the scoured dyeing target material with an natural dye. The eco-friendly dyeing process (S13) may be repeatedly carried out until brightness or chroma of color of the dyeing target material can be obtained as desired.

The mordanting process (S14) is a process of adding a mordant to the dyeing target material. The mordant has a function of fixing the natural dye to the dyeing target material. Examples of the mordant may include ashes, alum, acid, an iron solution, etc. Further, examples of the mordant may include quicklime, slaked lime (potassium hydroxide), and aluminum mordant. The aluminum mordant may be any one of aluminum acetate or aluminum chloride (AlCl₃.6H₂O).

The cleaning process (S15) is a process of washing the dyeing target material to remove residues of the dye and the mordant used from the eco-friendly dyeing process (S13) to the mordanting process (S14).

The drying process (S16) is a process of drying the dyeing target material washed in the cleaning process (S15) in the shade. When the drying process (S16) is completed, the combined dyeing method according to the exemplary embodiment of the present invention is completed.

FIG. 2 is a process flowchart of a combined dyeing method according to another exemplary embodiment of the present invention.

Referring to FIG. 2, a combined dyeing method according to another exemplary embodiment of the present invention includes: a scouring process (S22) of scouring a dyeing target material which is chemically dyed with an indigo-added chemical dye to remove impurities remaining in the dyeing target material; a reduction dyeing process (S23) of dyeing the dyeing target material by adding a dyeing solution to the dyeing target material; an oxidizing process (S24) of oxidizing the dyeing target material by exposing the dyeing target material to the air; a neutralizing process (S25) of neutralizing the dyeing target material by adding an acetate aqueous solution to the dyeing target material; a cleaning process (S26) of cleaning the dyeing target material; and a drying process (S27) of drying the dyeing target material.

A chemical dyeing process (S21) is a process of chemically dyeing a dyeing target material to be dyed with a chemical dye. The dyeing target material can be dyed by a conventional chemical dyeing method. The dyeing target material may include fiber, yarn, fabric, or the like, and preferably a plant material such as cotton. In the combined dyeing method according to another exemplary embodiment of the present invention, the dyeing target material is fiber, yarn, and fabric chemically dyed with an indigo-added chemical dye. Preferably, the dyeing target material is blue jeans dyed with indigo, but the dyeing target material of the present invention is not limited thereto.

The scouring process (S22) is a process of scouring the dyeing target material which is chemically dyed. The scouring process (S22) is a process of removing impurities including toxic substances remaining in the dyeing target material which is chemically dyed.

In the scouring process (S22), 5 g of a scouring agent is added to 10 L of water based on 200 g of the dyeing target material, and the dyeing target material is boiled in the water at a temperature ranging from 90° C. to 95° C. The dyeing target material is boiled for about 1 hour. In the case of a vegetable dyeing target material, sodium hydroxide (NaOH) may be used as a scouring agent, and in the case of an animal dyeing target material, sodium carbonate (Na₃CO₃) may be used, but the scouring agent is not limited thereto.

The reduction dyeing process (S23) is a process of dyeing the dyeing target material by adding a dyeing solution to the dyeing target material. The dyeing solution is prepared by mixing 1 L of water, 1 to 10 g of natural indigo powder, 5 to 10 g of hydrosulfite, and 2 to 5 g of sodium hydroxide through reduction for 20 to 40 minutes in water at a temperature ranging from 40° C. to 60° C. In this case, the water is at a pH ranging from 12 to 13.

The prepared dyeing solution is added to the dyeing target material to dye the dyeing target material. The reduction dyeing process (S23) is carried out with the dyeing solution at room temperature (20 to 30° C.) for 20 to 40 minutes. It the temperature of the dyeing solution is out of the range of room temperature (20 to 30° C.), it takes a long time so as to dye the dyeing target material, which may result in deterioration in productivity or may cause defects in dyeing.

The oxidizing process (S24) is a process of oxidizing the dyeing target material, which is completely dyed, by exposing the dyeing target material to the air. In the oxidizing process (S24), the dyeing target material may be exposed to the air for 10 to 30 minutes. The indigo component in the dyeing target material exposed to the air during this time period adsorbs oxygen in the air and is oxidized and expressed in blue.

If a dyeing target material is blue jeans, the dyeing target material is first dyed with an indigo-added chemical dye according to the chemical dyeing method and a color is expressed. Then, the dyeing target material is dyed with a natural indigo-added dyeing solution and a natural color is expressed.

The neutralizing process (S25) is a process of neutralizing the dyeing target material by adding an acetate aqueous solution to the dyeing target material. The acetate aqueous solution is prepared by adding 1 to 3 g of acetic acid to 1 L of water. In the neutralizing process (S25), the acetate aqueous solution prepared as such is added to the dyeing target material for 5 to 20 minutes so as to neutralize the dyeing target material.

The cleaning process (S26) is a process of washing the dyeing target material to remove residues of the dye and the mordant used from the reduction dyeing process (S23) to the neutralizing process (S25). The cleaning process (S26) is carried out three to five times to wash the dyeing target material until relatively clear water comes out of the dyeing target material.

The drying process (S27) is a process of drying the washed dyeing target material. The dyeing target material is dried in a sunny and airy spot. When the drying process (S27) is completed, the combined dyeing method according to the another exemplary embodiment of the present invention is completed.

It would be understood by those skilled in the art that various changes and modifications may be made without changing technical conception and essential features of the present invention. Thus, it is clear that the above-described embodiments are illustrative in all aspects and do not limit the present disclosure. For example, each component described to be of a single type can be implemented in a distributed manner. Likewise, components described to be distributed can be implemented in a combined manner. The scope of the present invention is defined by the following claims rather than by the detailed description of the embodiment. It shall be understood that all modifications and embodiments conceived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.