[0001] This application relies for priority upon Korean Patent Application No. 2001-13372, filed on Mar. 15, 2001, the contents of which are herein incorporated by reference in their entirety.
[0002] The present invention is a method of decolorizing blue jeans and, more particularly, to a method of decolorizing blue jeans based on the client-desired design.
[0003] Blue jeans are trousers that are made of fabrics obtained by colorizing closely woven fabric with blue colorant such as indigo blue dye. Therefore, the blue jeans become favorite jeans due to toughness, durability, and practicality. Like other fashion clothes, blue jeans have kept pace with various tastes or liking of users by changing their forms and colors.
[0004] Since blue jeans are originally rough as well as tough, a user, maker or merchant often intentionally makes the blue jeans worn out by a sandblasting or stonewashing process. The colors of initially colorized blue jeans are generally dark, so that there may be a need for partial decolorization thereof by reacting with a decolorant such as sodium hypochlorite (HOCl) during a drum processing. Furthermore, by attaching tapes to parts of the blue jeans during decolorization thereof, the parts are not decolorized to attain desired patterns or shapes.
[0005] However, conventional methods of making patterns on the blue jeans have difficulty in attaining desired patterns and clear colors. In a conventional decolorization process, a chemical solution such as sodium hypochlorite or calcium hypochlorite is put into an amount of water having a temperature between 60° C. and 80° C. (if necessary, abrading materials are added). Together with the water containing the chemical solution, blue jeans are rotated in a drum for 30 minutes or longer. In a case where tapes are attached to the blue jeans in order to attain a desired pattern, the water or other chemical materials may have an influence on the tapes. In addition, a high processing temperature may soften an adhesive element and turbulence may cause the tapes to thrust out from their original positions. Therefore, it is hard to attain the desired pattern. Further, if the tapes are thrust out from the blue jeans during the decolorization, tape-attached parts are also decolorized to make it hard to attain a clear color and pattern.
[0006] Also, the conventional decolorization method demands high costs for raising the temperature of a processing solution and continuously providing sodium hypochlorite and an amount of water. Wastewater is inevitably produced in the conventional decolorization. When the wastewater is discharged to a river, environmental pollution results. Therefore, if the wastewater is treated and discharged, additionally costs are incurred.
[0007] A main purpose of the present invention is to provide a method of decolorizing blue jeans with a clear color and a desired design.
[0008] Another purpose of the present invention is to provide an environment-friendly method of decolorizing blue jeans, which is capable of preventing waste, pollution, and waste treating cost.
[0009] Still another purpose of the present invention is to provide a method of decolorizing blue jeans, which is capable of cutting down decolorization cost by retrieving a chemical material to be used as a treatment material in waste produced during decolorization.
[0010] One aspect of the present invention is a method of decolorizing blue jeans using the steps of ;providing hydrochloric acid and sodium chloride solution to an electrolytic tub to generate chlorine gas and hydrogen gas, separating hypochlorous acid (HOCl) solution from sodium hydroxide, attaching tapes to the blue jeans to make a constant form, and submerging the tape-attached blue jeans in the hypochlorous acid to change the color of the blue jeans.
[0011] Another aspect of the present invention consists of providing hydrochloric acid (HOCl) and sodium chloride solution to an electrolytic tub to generate chlorine gas and hydrogen gas, separating hypochlorous acid solution from sodium hydroxide, colorizing the blue jeans with an oil-based colorant oxidized by the hypochlorous acid to make a constant form, and submerging the tape-attached blue jeans in the hypochlorous acid to change the color of the blue jeans.
[0012] The oil-based colorant is identical to a colorant colorized on the blue jeans. When additionally colorizing the blue jeans, colorization amount is controlled at each part of the blue jeans through a plurality of control steps.
[0013]
[0014] Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular feature of the invention selected for illustration and are not intended to define or limit the scope of the invention.
[0015] Referring now to
[0016] The electrolytic tub
[0017] The sodium metal immediately reacts with water to produce sodium hydroxide. The sodium hydroxide is dissolved in the water to produce sodium hydroxide solution. At this time, hydrogen gas is produced and exhausted. Chlorine ions are induced to the anode
[0018] Therefore, the content of sodium chloride in the electrolytic tub
[0019] The electrolytic tub
[0020] If a concentration of the hypochlorous acid reaches a predetermined level in the anode space
[0021] A chlorine trap duct
[0022] Alternatively, the confluence may serve as a reaction chamber just before scrubbing the trapped gases. In the confluence, hydrogen reacts with chlorine to produce a hydrogen chloride gas that is provided to a processing chamber in the scrubber
[0023] A shower facility
[0024] Thus, contaminants are not discharged to the air while only innoxious gases are exhausted via the scrubber
[0025] A sodium chloride solution is put into a retrieving tub
[0026] Decolorization-desired blue jeans
[0027] With variation of the colorant elements, the blue jeans are gradually decolorized. A degree of the decolorization is controllable with the submerging time, a concentration of the hypochlorous acid, a processing temperature. Since the hypochlorous acid used to decolorize the blue jeans
[0028] The diluted hydrochloric acid solution is provided to the electrolytic tub
[0029] wherein the R group (R—) is an atomic group having any structure, and a conventional colorant element is made up of an organic group.
[0030] Generally, oxidized or chlorinated colorant elements are continuously attached to the blue jeans. For that reason, the oxidized or chlorinated colorant elements are not diffused to the processing tub
[0031] Although it has been described that all the steps are separately performed in this embodiment, a continuous process may be made in which each pipe continuously puts a material out by controlling a rotation speed based on a content of provided materials and an apparatus and environmental conditions such as temperature and pressure for each processing reaction. Since the continuous process does not require manpower for operating a valve or pump of each pipe, automation and mechanization can easily be realized in the whole process.
[0032] According to the present invention, because hypochlorous acid having a strong oxidizing power is used, it is not necessary to raise a processing temperature. Therefore, tapes are not separated from the blue jeans during a process for decolorizing the blue jeans to obtain a design of client-desired form and clearness. Further, all materials are circulated except oxygen or chlorine. If water for supplementing oxygen and a part of exhausted gas or a chlorine gas is supplemented, the process for decolorizing blue jeans can continuously be performed only by supplying electricity. Compared with a conventional process in which all decolorizing elements are provided anew for one time treatment and waste is inevitably created, the decolorizing process according to the invention can be recycled only by supplying electricity and supplementing eliminated elements. Thus, costs for providing material and treating waste can be saved. First of all, the present invention makes it possible to realize an environment-friendly process.