Description

FABRICATING METHOD FOR SILK CAPABLE OF WASHING

Technical Field

[1] The present invention relates to a method for fabricating water- washable silk; and, more particularly, to a method for fabricating water- washable silk by performing thermal treatment onto yarn obtained from silkworms to thereby maximize applicability of silk. Background Art

[2] Silk is obtained from silkworm cocoons. Raising healthy silkworm cocoons requires thoughtful labor such as delicately controlling temperature and humidity and adjusting the quantity and quality of mulberry leaves.

[3] Silk yarn obtained from silkworm cocoons goes through spinning, weaving, refining, dying and processing to be manufactured as silk fabric.

[4] Silk fabric manufactured as above has been spotlighted as the best material for clothes for a long time due to its high quality and functional properties. Silk has excellent water absorptiveness, moisture absorptiveness, moisture-proof, and air- permeability. Because silk has a 1.5 to 2 times as high water absorptiveness as typical cotton, it absorbs sweat quickly to thereby reduce uncomfortableness on skin and maintain fresh and dry state. This eventually contributes to active metabolism of skin and maintains skin healthy. Also, silk has a low heat transmission compared to cotton or synthetic fabric. Thus, silk has an excellent property of keeping warmth. In summer, silk clothes give cool sense of touch, while they give warm sense of touch in winter. Moreover, silk is composed of protein including about 18 kinds of amino acids, it has an excellent property of absorbing lipid on skin and excellent antibiotic effect. Therefore, it protects skin from allergy and stress. This allows people with sensitive skin to wear clothes without feeling friction or irritation. Particularly, silk is good for relieving the skin of Atopy patients. Besides, silk provides excellent effects of both health and beauty at the same time.

[5] However, silk is fragile to fire and water. When silk is exposed to fire or water, it shrinks drastically, and since it irregularly extends or shrinks in the direction of woof or warp, wrinkles are made. Due to these properties, silk cannot be washed with water but it should be dry-cleaned. Therefore, it is difficult to use silk for general garments which are water- washable. Particularly, it is almost impossible to use silk as fabric requiring high tensile strength and stone washing, such as blue jeans, and fabric requiring comfortableness and functional properties such as mountain climbers' suit, sports wears, and casual wears.

[6] Therefore, it is required to develop a method for processing silk to be water- washable to thereby overcome the limitation of silk in its applicability and use silk for diverse kinds of clothes including jeans. Disclosure of Invention

Technical Problem

[7] The present invention is directed to providing a method for fabricating water- washable silk to overcome the limitation of silk in its applicability and use silk for diverse kinds of clothes. Technical Solution

[8] In accordance with an aspect of the present invention, there is provided a method for fabricating water- washable silk, which includes: preparing yarn by treating silkworms; weaving fabric out of the yarn; performing a processing of wetting the fabric with water, drying the fabric to be shrunken, and extending the shrunken fabric more than once; and fixing the fabric obtained after the processing by applying heat to the fabric.

[9] Said preparing yarn by treating silkworms may include: extracting yarn out of silkworms which are raised indoor under a controlled environment or raised naturally in field; plying more than two strands of yarn in a wet environment to produce multiply yarn; and drying the multi-ply yarn.

[10] The fabric may be woven using silk yarn for both woof and warp in said weaving fabric out of the yarn.

[11] The fabric may be woven using silk yarn for one between woof and warp and yarn of another material for the other and the silk yarn and the yarn of another material may be blended at a predetermined ratio.

[12] The yarn of another material may be cotton.

[13] The processing may include: removing impurities by washing the fabric with water; rapidly drying the fabric by applying direct heat to the fabric and having the fabric shrunken; and extending the shrunken fabric.

[14] The repetition number of the processing may be decided according to the blending ratio, thickness, and/or weight of the fabric.

[15] The extended fabric is heated directly to be fixed in said fixing the fabric.

[16] The water- washable silk fabricating method may further include dying silkworms, dying the yarn, or dying the fabric.

Advantageous Effects

[17] According to the technology described above, fabric is woven from yarn spun out of silkworms and the fabric attains a property of an enhanced tensile strength and a property of not shrinking even after washed with water by repeatedly going through a thermal process of being shrunken and extended between moisture and heat in a

plurality of times until the woof and warp have a shrinkage rate of axial error range not greater than 3%. Therefore, fabric having diverse thickness and weights can be woven according to diverse usages, such as suits, gowns, shirts, casual pants, skirts, curtains, outer cover of sofa, bedclothes and so forth as well as blue jeans which is tough and has a stylish outline.

[18] Also, the technology of the present invention can reduce production costs because it is possible to fabricate cotton-silk blended fabric, other than silk fabric. Brief Description of Drawings

[19] Fig. 1 is a flowchart describing a method for fabricating water- washable silk in accordance with an embodiment of the present invention. Best Mode for Carrying out the Invention

[20] The present invention provides a method of fabricating silk fabric and silk blended fabric that are not shrunken even after washed with water through thermal treatment in the stages of spinning silk yarn and weaving silk fabric.

[21] Fig. 1 is a flowchart describing a process for fabricating water- washable silk in accordance with an embodiment of the present invention.

[22] The silk fabricating process includes preparing yarn spun out of silkworms in step

SlOO, dying the yarn in step Sl 10, plying and twisting the yarn in steps S 120 and S130, weaving fabric out of the yarn in steps S140a and 140b, wetting, drying and extending the fabric in steps S 150 to 180, and fixing the fabric by applying heat to the fabric in step S 190.

[23] According to an embodiment of the present invention, the yarn and the fabric are spun and woven out of natural silkworms, which are raised naturally in outdoor fields being exposed to rain and wind. The naturally raised silkworms produce silk having higher tensile strength than silkworms raised indoor under an environment of controlled temperature and humidity.

[24] According to another embodiment of the present invention, the yarn and the fabric are spun and woven out of silkworms raised indoor. The silk produced by the silkworms raised indoor has a disadvantage of lower tensile strength than the silk produced by the naturally raised silkworms but it is advantageous in that it can be easily obtained and has low production costs. When silk spun out of the silkworms raised indoor is used, it is better to make it into multi-ply yarn than into single-ply yarn.

[25] In the step SlOO, yarn is extracted out of silkworms. Dried silkworm cocoons are boiled in hot water of about 90 to 100 ⁰ C and yarn is extracted. Generally, a piece of string is extracted from 7 silkworm cocoons. The string is of about 21 deniers, which is most widely used. The strings extracted from silkworms include short fibres and long

fibres. Long fibres have better gloss and higher price than short fibres. Moreover, it is easier to use long fibres than to use short fibres.

[26] To improve the weaving property, the extracted yarn goes through chemical treatment, and then it is wound on skeins, dyed, wound off onto a spinning wheel, and wound again onto bobbins. The chemical treatment is to remove sericin on the surface of the extracted yarn.

[27] According to an embodiment of the present invention, yarn extracted from naturally raised silkworms is a continuous filament including about 72 to 81 wt% fibroin and 19 to 28 wt% sericin surrounding the fibroin. Sericin is a substance formed as the surface of the yarn is oxidized in the air and it makes the surface of the yarn dull and stiff. Sericin is an amorphous substance that can be dissolved in a warm soap solution. When sericin is removed using a soap solution, only fibroin remains and the gloss and sense of touch that are specific to silk are revealed. Meanwhile, since the yarn extracted from naturally raised yarn is thin, it has a wide surface area. Also, since the yarn does not have scales, it has a frictional coefficient different from other textiles and causes much static electricity. When the yarn obtained from naturally raised silkworms is blended with yarn of another material, sufficient pre-preparation treatment is required because the frictional treatment different from the yarn of another material and the presence of sericin deteriorate the weaving property.

[28] When the chemical treatment is over, the yarn is dyed in the step Sl 10. Generally, dying is divided into three methods according to the time when dying is performed.

[29] Dying may be performed onto silkworm cocoons before yarn is extracted from the silkworm cocoons. This method is advantageous because vivid color is obtained. However, the method leaves many impurities and some of dyed yarn cannot be used. In other words, the loss rate of yarn is high but the dying method is used sometimes to obtain high-quality color. The other dying methods are yarn dying and over-dying. Yarn dying is a method of dying yarn and over-dying is a method of dying fabric. According to an embodiment of the present invention, when over-dying is applied, fabric is woven and dyed before subsequent processes.

[30] Meanwhile, most woven fabrics with indigo textile printing such as cotton blue jeans adopt over-dying for stone washing effect. Silk blue jeans fabric fabricated according to an embodiment of the present invention may adopt any one between yarn dying and over-dying according to usage and present the unique effect of silk.

[31] According to an embodiment of the present invention, when yarn obtained from silkworms raised indoor is used, it is desirable to use the over-dying method. According to another embodiment of the present invention, when yarn obtained from naturally raised silkworms is used, it does not matter whether yarn dying or over-dying is used.

[32] In the steps S 120 and S 130, yarn is plied and twisted according to usage of the yarn.

A single-ply yarn refers to yarn including single strands of string held together, and it does not require any additional processing. On the other hand, a multi-ply yarn is formed of more than two strands of string plied with each other. Plying is a process of simply combining multiple strands of string together, whereas twisting is a process that gives a twist to multi-ply yarn or single-ply yarn.

[33] When multi-ply yarn is used in the present invention, the yarn goes through the following process.

[34] First, more than two strands of string are plied by spaying water continuously or applying steam. Herein, the yarn is densely and strongly plied to form a multi-ply yarn while both ends of the yarn are strained by a uniform strength. After the multi-ply yarn is formed, the multi-ply yarn is dried rapidly while both ends of the multi-ply yarn are fixed tightly. As for the method of rapidly drying the multi-ply yarn, there are methods of quickly passing the multi-ply yarn over fire with a predetermined space from the fire at a predetermined speed or heating the multi-ply yarn by transferring fire at a predetermined speed. These are called direct heating methods. When the direct heating method is applied, it takes a short time to dry the yarn and shrinkage occurs freely, compared to a conventional method using a heated metal plate or using warm wind. It is obvious to those skilled in the art that the process of applying moisture and heat onto yarn can be also applied to single-ply yarn. For example, when single-ply yarn is provided with moisture and dried quickly through direct heating, the single-ply yarn also shrinks.

[35] When yarn is obtained from silkworms raised indoor, it is desirable to repeatedly perform the plying process more than when yarn obtained from naturally raised silkworms is used. To be specific, when the yarn is plied, it is desirable to ply the yarn more tightly than the case when yarn obtained from naturally raised silkworms is used. Also, it is desirable to repeat the process of forming multi-ply yarn in a wet environment and drying the multi-ply yarn more than the case when yarn obtained from naturally raised silkworms is used.

[36] When the multi-ply yarn is formed, fabric is woven in the steps S 140a and S 140b.

The fabric weaving process includes spindling, warp winding and weaving.

[37] Spindling is a process of winding woof, and warp winding is a process of winding warp as long as the warp is set up on a loom to be woven. When the woof and warp are wound, fabric including plain fabric, twill fabric and satin fabric is woven using a spinning and weaving machine.

[38] Meanwhile, 100% silk fabric can be woven by using silk yarn for the woof and warp in the step S 140a, and it is also possible to weave silk blended fabric by setting yarn of a different material for either woof or warp.

[39] When silk blended fabric is woven, yarn of diverse materials can be blended with silk yarn. In an embodiment of the present invention, a case where silk is blended with cotton will be described as an example. When silk yarn is blended with cotton yarn in the step S 140b, the properties of cotton are added up to thereby weave jeans, climbers' suit, and fabric appropriate for bad weather such as snow and rainstorm. When silk yarn is blended with cotton yarn, the properties of silk and cotton can be obtained and thus woven fabric of the silk and cotton can be used for diverse usages.

[40] When silk yarn is blended with cotton yarn, the ratio of silk yarn and cotton yarn can be decided variously according to the usage and thickness of woven fabric. For example, to obtain the properties of cotton while maximizing the properties of silk, the blending ratio of silk and cotton is decided as 68:32 in an embodiment of the present invention.

[41] When silk is blended with cotton, silk yarn is used as warp and cotton is used as woof. To weave fabric at a ratio of silk and cotton 68:32, 32s/3 cotton yarn and 68s/2 silk yarn are prepared. The counts and thickness of the cotton yarn and silk yarn may be decided according to the usage or thickness of fabric.

[42] The cotton yarn and silk yarn are used to weave 100% silk fabric and silk-cotton blended fabric with spinning and weaving machine.

[43] When the fabrics are woven, they go through a subsequent processing to acquire a water- washable property. The processing includes removing impurities by washing fabric with water in step S 150, rapidly drying and shrinking fabric through direct heating in step S 160, and extending the shrunken fabric in step S 170.

[44] In the step S 150, sericin remaining on fabric and other impurities are removed. To remove sericin, soap water may be used and impurities such as soil, dirt and dyestuffs are removed through washing. Through the processing, fabric is shrunken by water.

[45] In the step S 160, the fabric is rapidly dried through direct heating. Herein, the fabric is forcibly shrunken by heat. When the fabric is shrunken, both ends of the fabric is set on a machine and extended in the step S 170 to thereby extend the fabric which has shrunken forcibly by the heating.

[46] The above processing is repeated about one to three times, and the repetition number of the processing may be decided for the stability of fabric according to the blending ratio or whether the fabric is blend fabric or not. Also, the more the processing is repeated, the higher the tensile strength of the fabric becomes and the thicker the fabric becomes. In step S 180, the repetition number may be decided by measuring the thickness and weight of the fabric and deciding whether desired thickness and weight are achieved.

[47] After the processing is completed, the fabric is directly heated again to be fixed in step S 190. In the fabric fixing step, the fabric passes through high temperature

minutely and very quickly. The time and temperature of the thermal treatment may be diced according to the thickness and weight of the fabric. For example, in case of fabric for silk blue jeans which weighs about 39Og per meter, 60-meter fabric rapidly passes through over 10-meter flame for one minute to be fixed.

[48] Through the processing and fabric fixing process, the fabric comes to have an axial shrinkage rate not greater than about 3% in the woof and warp.

[49] According to the present invention described above, silk attains high tensile strength and does not shrink even when it is washed with water by extracting long fibres and short fibres according to the properties of silkworms, fabricating single-ply yarn, multi-ply yarn and twisted yarn, setting up the yarn on spinning and weaving machine as woof and warp to weave plain fabric or twill fabric, repeating a process of shrinking the woven fabric through water and heat and extending the shrunken fabric in a plurality of times until the fabric attain an axial shrinkage rate not greater than 3% in the woof and warp. Through the method, silk comes to attain excellent properties in chemical and physical tests such as color fastnesses to water, sea water and light and high chemical-resistance and durability.

[50] Therefore, fabric having diverse thickness and weights can be woven according to diverse usages, such as suit, gown, shirts, casual pants, skirts, curtains, outer cover of sofa, bedclothes and so forth as well as blue jeans which is tough and has a stylish outline. Also, it is possible to weave blended fabric such as blended fabric of silk and cotton other than 100% silk fabric. The blended fabric may reduce the production costs.

[51] Meanwhile, since silk has excellent moisture absorptiveness, moisture-proof, and air- permeability, it can absorb sweat quickly to thereby reduce uncomfortableness on skin and maintain fresh and dry state. This eventually contributes to active metabolism of skin and maintains skin healthy. Also, silk has an excellent property of keeping warmth. In summer, silk clothes give cool sense of touch, while it gives warm sense of touch in winter. Moreover, it has an excellent property of absorbing lipid on skin and excellent antibiotic effect. Therefore, it protects skin from allergy and stress. This allows people with sensitive skin to wear clothes without feeling friction or irritation. Particularly, silk is good for relieving the skin of Atopy patients.

[52] While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.