A SEA-ISLAND TYPED COMPOSITE FIBER FOR WARP KNIT TREATED RAISING, AND A PROCESS OF PREPARING FOR THE SAME

Abstract: The present invention relates to a sea-island type composite fiber and process of preparing the same. In accordance with the present invention, a sea-island type composite fiber for a raised warp knit fabric which is prepared by the direct spin draw method by using alkali soluble copolymer polyester as a sea component and polyester mainly consisting of polyethylene terephthalate of more than 90 mole% as an island component, wherein the composite fiber is characterized in that it satisfies the following thermal properties and viscoelastic properties: - a number of presence of melting point peaks: 4, - a temperature of main melting point peak of sea component [Tms]: 220 SIMILAR 235 DEG C, - a temperature of main melting point peak of island component [Tmi]: 245 SIMILAR 255 DEG C, - a first transition peak temperature [T alpha ] of viscoelastic index (tan delta ): 120 SIMILAR 150 DEG C and - a viscoelastic index value [tan delta alpha ] of the first transition peak ( delta -peak): 0.10 SIMILAR 0.20. The sea-island type composite fiber prepared by the present invention has good thermal shrinkage properties and excellent raising property and improves the appearance and touch of warp knit.

Description: A SEA-ISLAND TYPED COMPOSITE FIBER FOR WARP KNIT TREATED RAISING, AND A PROCESS OF PREPARING FOR THE SAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sea-island type composite fiber for a raised warp knit fabric which can improve the quality and physical properties of the raised warp knit fabric, i.e., an end product and process of preparing the same. 2. Description of the Related Art In a warp knitting process for preparing a warp knit fabric by using a sea-island type composite fiber, a high quality of yarn, particularly, the smoothness of yarn is required because of a high knitting speed. In addition, the post finishing process for preparing a warp knit fabric requires a large number of complex steps such as weight loss, raising, dyeing and the like, it is necessary to control the thermal properties and viscoelastic properties of yarn appropriately. Specifically, the thermal properties and viscoelastic properties specified according to the internal structure of each a sea component and an island component of a sea-island type composite fiber is very important in preparing a warp knit. The sea-island type composite fiber is prepared by using alkali soluble polymer as a sea component and fiber forming polymer as an island component and by conjugated-spinning them into a sea-island type, which is produced mainly for the purpose of preparing a fine denier fiber. In other words, after preparing the sea-island type composite fiber, the sea component of alkali soluble polymer is dissolved by treating the sea-island type composite fiber with an alkali solution, thus to prepare a fine denier fiber composed of only island components. In this way, the method for preparing the fine denier fiber from the sea- island type composite fiber is advantageous in that the finer denier fiber of an excellent workability of spinning and drawing can be obtained, as compared to the method for preparing the finer denier fiber by direct spinning, while it requires a process for dissolving and removing the sea component polymer with an organic solvent in the finishing process after weaving or knitting. Thus, the property of being soluble in an organic solvent or solution is very important for the sea component polymer. Generally, as the sea component polymer used for the sea-island type composite fiber used in warp knitting, alkali soluble copolymer polyester is mainly used. The reason of which is because it is possible to dissolve the sea component from an alkali solution and weight loss facilities widely applied in the weight loss processing of general polyester fabric without using a special apparatus and the organic solvent requiring a high recovery cost. If the island component polymer is nylon, the dissolution speed of the sea component is not so important because the extent that the nylon is penetrated by the alkali solution is very low in dissolving the sea component. While, if the island component is polyester, the island component is penetrated before the sea component is completely dissolved in a case that the dissolution speed of the sea component is low because the polyester is weak to alkali, for thereby abruptly degrading the physical properties of yarn after the dissolution. Resultantly, the raising property becomes defective and it is difficult to gain desirable appearance and touch of an end product. On the other hand, if the dissolution speed of the sea component is high, the occurrence of the above problems can be prevented and the alkali density and the dissolution temperature and time can be reduced, thereby decreasing the dissolution cost and increasing the productivity. To increase the dissolution speed of the sea component, the content of a copolymer compound should be increased. However, if the content of the copolymer compound is excessively increased, the sea component becomes an amorphous polymer with no melting point but only softening point while the dissolution is improved, thus making spinning difficult. The prior art techniques for preparing alkali soluble polyester used in preparing the sea-island type composite fiber includes the following methods: 1 ) method for copolymerizing dimethy-5-sulfoisophthalate sodium salt (hereinafter, "DMIS") or polyalkyleneglycol (hereinafter, "PAG") of a low molecular weight in a polyester polymerization process; 2) method for blending polyester with PAG of a high molecular weight; and 3) method for blending polyester polymer with PAG of a.high molecular weight. In the case of preparing the sea-island type composite fiber by spinning, drawing and false-twisting the alkali soluble polyester of the prior art as the sea component and the polyester as the island component, the flat property of yarn is degraded and the knitting property becomes poor. The fait property of yarn improve the processinf ability by reducing the friction between yarn and needle of knitter. More specifically, since a false-twisted yarn has a tendency of bulky, the knitting property is degraded in a high speed warp knitting. In addition, since the thermal properties and viscoelastic properties of yarn is poor, the raising property is degraded and the appearance and quality of a raised warp knit fabric become worse in the subsequent raising process after the warp knitting. SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a sea-island type composite fiber which is made suitable for yarn for a raised warp knit fabric by controlling the thermal properties and viscoelastic properties of the yarn appropriately. It is another object of the present invention to provide a method of preparing a sea-island type composite fiber by controlling the thermal properties and viscoelastic properties of a spin draft yarn(x in Fig 1 ) during the preparing process. In accordance with this present invention to achieve the above objects, a sea-island type composite fiber for a raised warp knit fabric which is prepared by the direct spin draw method by using alkali soluble copolymer polyester as a sea component and polyester mainly consisting of polyethylene terephthalate of more than 90 mole% as an island component, wherein the composite fiber is characterized in that it satisfies the following thermal properties and viscoelastic properties: - a number of presence of melting point peaks : 4, - a temperature of main melting point peak of sea component[Tms] : 220~235°C, - a temperature of main melting point peak of island component[Tmi] : 245~255°C, - a first transition peak temperature[Tα ] of viscoelastic index (tanδ ) : 120-150 °C and - a viscoelastic index value [tanδ α ] of the first transition peak (δ -peak) : 0.10-0.20. Hereinafter, the present invention will be described in detail. The sea-island type composite fiber of the present invention is prepared by using alkali soluble copolymer polyester as a sea component and polyester mainly consisting of polyethylene terephthalate of more than 90 mole% as an island component. Specifically, the sea-island type composite fiber is prepared by spinning the sea component and the island component by an ordinary sea-island type conjugated spinning machine, and then drawing them between a first Godet roller 2 and a second Godet roller 3, and then winding up them. In the present invention, the raising property and sea-island shaping property are improved by properly adjusting the melt viscosity of the sea component and island component. Generally, a shear flow is occurred to fiber by a pressure applied to a spinneret from an extruder during a spinning process, and the flow rate and shear rate are low in the extruder while they are very high in the spinneret. Such a shear stress according to a shear rate is called the melt viscosity(MV), which is different according to polymer properties. However, with respect to the sea-island type composite fiber prepared by conjugated-spinning more than two kinds of polymers, since the melt viscosities of sea components are different from each other, there occurs a difference between their shear stresses, resultantly affecting the sea and island shaping of the composite fiber and the physical properties of composite fiber. Therefore, to obtain the physical properties required for an uniform sea- island shaping and use, it is necessary to select sea-island component polymer having a proper melt viscosity. Particularly, in the case of a raised warp knit product, in order to express the raising property and the appearance and touch of fine yarn, it is necessary that polymers used for the sea-island type composite fiber keep their relative viscosity properly, rather than their melt viscosity. In the present invention, the difference (hereinafter, "ΔMVg.ooo") between the melt viscosity of island component polymer and the melt viscosity of sea component polymer at a shear rate of 9,000(1/s) is 20-70% of the difference (hereinafter, "ΔMV500") between the melt viscosity of island component and the melt viscosity of sea component at a shear rate of 500(1/s). That is, the value of ΔMV at the spinneret should be smaller than the value of ΔMV at the extruder. In other words, the difference (ΔMV) in melt viscosity between the island polymer and the sea component polymer according to an increase of the shear rate should be reduced. Otherwise, the orientation property of the island component is decreased, the knitting property is degraded because a sufficient drawing is difficult, and raised fibers are entangled with one another in warp knit. Fig. 5 is a graph illustrating a change in ΔMV according to an increase of a shear rate. In Fig. 5, it is found that the difference in melt viscosity between the island component and the sea component is decreased gradually as the shear rate is increased. In addition, it is preferred that the melt viscosity (hereinafter, "MVs") of the sea component at a shear rate of 500-9, 000(1/s) is lower than the melt viscosity (hereinafter, "MVi") of the island component (MVs ≤ MVi). Fig. 4 is a graph illustrating the correlation between the melt viscosity and shear rate for each component. If the melt viscosity (MVs) of the sea component is larger than the melt viscosity(MVi) of the island component polymer, the cross section shaping of the sea-island type fiber might be difficult. This causes a decrease in number of island components or the wreck of uniform formation of island components, and thusly the raising property becomes poor in raising process and it is made difficult to express the appearance and touch of an end product. Moreover, it is preferred that the difference in melt viscosity (hereinafter, "ΔMV") between the sea component and the island component is lower than 1 ,000 poises [ΔMV≤ 1 ,000]. If the difference (ΔMV) in melt viscosity between the sea and island components is more than 1 ,000 poise, the island components become adhesive to one another during spinning and there may be generated unseparated fibers in which the island components are not separated even after the dissolution. Due to this, there is a risk that the fiber raising state becomes non-uniform in warp knit raising, the appearance becomes unclean, the writing effect becomes weak and the touch becomes rough. The melt viscosity of the island component polymer can be adjusted by an intrinsic viscosity, and the melt viscosity of the sea component polymer can be adjusted by properly controlling the kinds of copolymer, constant weight of copolymer and copolymerization conditions. As an example of adjusting the melt viscosity of the sea component polymer, DIMS of 3-15 mole% is copolymerized into polyethylene terephthalate, to which polyethyleneglicol of 4-20 weight % having a number average molecular weight more than 8,000 can be added. The present invention is more advantageous to a high speed warp knitting because it can prepare a yarn having a flat property, as compared to the method of preparing a bulky sea-island type composite fiber by the spinning, drawing and false-twisting method. In addition, in the present invention, the appearance and touch of a raised warp knit fabric is improved by appropriately controlling the thermal properties and viscoelastic properties of the sea and island components of the yarn. In addition, in the present invention, the thermal properties and viscoelastic properties of the sea and island components of the yam on the first Godet roller(hereinagter "spin draft yarn") are controlled during the preparing process in order to adjust the thermal properties and viscoelastic properties of the sea and island components within a predetermined range. The thermal properties and viscoelastic properties of the spin draft yarn can be adjusted by appropriately combining a drawing teijiperature, a drawing ratio, a cooling condition and a melt viscosity of the sea component and island compoment. Specifically, the number of presence of melting point peaks of the spin draft yarn(x) is adjusted to be less than 4, and a second transition peak temperature [Tβ ] on a graph of a viscoelastic index (tanδ ) is adjusted to be - 60 - -30 °C. Moreover, a viscoelastic index value (tanδ β ) of the second transition peak (β -peak) is adjusted to be 0.04-0.10. In addition, a first transition peak should not be present on the graph of the viscoelastic index (tanδ ) of the spin draft yarn(x), and the total heat of fusion (ΔHx) of crystal of the spin draft yarn (x) should satisfy the following formula with the total heat of fusion (ΔHy) of crystal of drawn and wound sea- island type composite fiber (hereinafter, "spin draw filament"). 1.1 x ΔHy < ΔHx < 1.5 x ΔHy A variety of physical properties of the yarn on the first Godet roller are physical property values measured by the method to be described later. The sampling method of the yarn on the first Godet roller are as below. Cutting the spinning yam at the front end portion of the first Godet roller by means of capturer, and almost simultaneously with cutting the spinning yarn at the rear end portion of the first Godet roller, and then sampling the filament wound up on the surface of the first Godet roller as soon as it is cut. More specifically, the yarn disposed on the surface of a filament layer wound up to the first Godet roller is sampled as soon as it is cut in order to prevent a change in the physical properties due to the temperature of the first Godet roller. The thusly prepared spin-draw filament (y) of the present invention has the thermal properties and viscoelastic properties as shown in Figs. 2 and 3. Particularly, the number of presence of melting point peaks of the spin-draw yarn(y) is 4 including Ya, Yb, Yc and Yd of Fig. 3. That is, a main melting point peak (Ya) of the sea component, a sub melting point peak (Yb) of the sea component, a main melting point peak (Yc) of the island component, and a sub melting point peak (Yd) of the island component are formed. The main melting point peak temperature [Tmi] of the island component is 245-255 °C, and the sub melting point peak temperature [Tmi'] of the island component is 2-10°C higher than [Tmi]. The main melting point peak temperature [Tms] of the sea component is 220-235 °C, and the sub melting point peak temperature [Tms'] of the sea component is 2-10 ° C higher than [Tms]. Here, the melting point of a crystal region refers to a maximum temperature of a combination of temperatures at which polymer crystal is melted. The melting point of the same polymer is dependant on a size of crystal and it becomes higher as the crystal becomes larger. When the melting point of one polymer is divided into more than two, the main peak of the melting point is a peak at a low temperature side and the sub peak of the melting point is a peak at a high temperature side. The reason why the melting point of one polymer is divided into two is because a distribution of crystal sizes of polymers are divided into two by an external influence. If the main melting point peak is present at a temperature higher than the sub melting point peak, this means that crystals of a larger size are more than crystals of a smaller size. While, if the main melting point peak is present at a temperature lower than the sub melting point peak, this means that crystals of a smaller size are more than crystals of a larger size. In addition, with respect to the spin-draw yarn(y) of the present invention, the total melting heat (ΔHi) of an island component crystal is 2-5 times larger than the total melting heat (ΔHs) of a sea component crystal. Moreover, the total melting point (ΔHy) of the spin-draw yarn(y) crystal is 1.1-1.5 times larger than the total melting heat (ΔHx) of the spin draft yarn(x) crystal. Herein, the total melting heat(ΔHy) of spin draw yarn(y) is equal to value ΔHi+ΔHs. The melting heat of crystal refers to a quantity of heat per unit weight required for melting every small and large crystals in one polymer. The melting heat value of crystal becomes larger as the crystallinity becomes larger. Meanwhile, with respect to the spin-draw yarn(y) of the present invention, a first transition peak temperature [Tα ] on a graph of a viscoelastic index (tanδ ) is 120-150 °C, and a second transition peak temperature [Tβ ] is - 50 - -20 ° C. In addition, the viscoelastic index [tanδ α ] value of the first transition peak (α -peak) is 0.10 - 0.20, and the viscoelastic index [tanδ β ] of the second transition peak (β -peak) is 0.03-0.08. The viscoelastic index [tanδ ] represents a degree of energy loss by a frictional heat and braking generated by an internal molecular motion when an external force is given to polymer, which is a value obtained by dividing a viscous modulus by an elastic modulus. The first transition peak (α -peak) represents a long distance chain movement of molecular in amorphous region related to glass transition. The second transition peak (β -peak) seen at a lower temperature than the first transition peak (α -peak) represents a crank shaft movement caused by a near chain movement of between amorphous region and crystal region. With respect to the sea-island type composite fiber of the present invention having the above-described thermal properties and viscoelastic properties, the appearance and touch of a raised warp knit fabric are improved because of an excellent raising property. In addition, the sea-island composite fiber of the present invention has a retention of yarn strength of more than 82% after dissolving the sea component. As described above, with respect to the sea-island type composite fiber of the present invention, the melt viscosities of sea-island components harmonizes with one another. As a result, the formability of filament cross section shape, raising property and touch are excellent, and the degradation of the physical properties of the yarn is minimized in dissolving a sea component and raising process. Resultantly, the sea-island type composite fiber of the present invention is suitable particularly for the yarn used in preparing a raised warp knit fabric. A variety of physical properties of yarn and raised warp knit fabric are evaluated as follows. • melting poin °C ) / heat of fusion of crvstaKJoule/g) The melting point and melting heat of crystal are measured by a differential scanning calorimetry (DSC). As a measurement apparatus, "DSC- 7" of PERKIN ELMER is used. As measurement conditions, a sample amount is sea-island type composite fiber of 5mg, a sample state is set to a state where tens of strands of sea-island type composite fibers are cut in alignment, a heating rate speed is +10°C/min, and running is a first run. • viscoelastic properties (viscoelastic index/first transition peak temperature/ second transition peak temperatrel The viscoelastic properties are measured by the Rheovibron testing method. As a measurement apparatus, "Rheovibron-ll" of ORIENTEC is used. As measurement conditions, a sample gauge length is 3cm, a temperature range is -120 -200 °C, an amplitude is 16jum (L mode), and a heating rate is +2°C/min. • melt viscosity The melt viscosity according to a shear rate is measured by applying a shear stress to a sample(chip) by using a capillary rheometer (spec: L=25.38mm, D=0.762mm, L/D=33.31 mm) of INSTRON. At this time, the melting temperature of polymer is 290 °C, the shear rate is continuously changed in the ranges from 500(1 /s) to 9,000(1 Is), and the drying condition of the island component polymer(chip) and sea component polymer(chip) is set to 150°C x 5 hours in the vacuum state. • sea-island cross section shaping property 500 samples are prepared by sampling a composite fiber section, and the uniformity and seperation of a sectional form are observed and evaluated by a microscope. Specifically, if the sectional form is uniform and the number of unseparated island components is two or less, the shaping property is evaluated to be excellent, if the sectional form is not uniform and the number of unseparated island components is two or less, the shaping property is evaluated to be good, if the sectional form is uniform and the number of unseparated island components is 3-4, the shaping property is evaluated to be moderarate, and if the number unseperated of island components is five or more, the shaping property is evaluated to be poor. • raising property The raising property is measured by dyeing a raised warp knit fabric and then observing the number of occurrence of defective portions per square meter (e.g., raised fiber aggregation, raised fiber release and the like). Specifically, if the number of occurrence of defective portions per square meter is two or less, the raising property is evaluated to be excellent. If the number of occurrence of defective portions per square meter is 3, the raising property is evaluated to be good. If the number of occurrence of defective portions per square meter is 4-6, the raising property is evaluated to be moderate. If the number of occurrence of defective portions per square meter is seven or more, it is evaluated to be poor. • Retention of yarn strength after reduction of sea component By the above-described method, the yam(composite fiber) strengths before and after the reduction of the sea component are obtained by Instron, and then the retention of yarn strength maintenance rate (%) after the dissolution of the sea component is obtained by substituting the yarn strengths before and after the dissolution of the sea component by the following formula. The dissolution of the sea component is performed by processing the sea-island type composite fiber in a sodium hydroxide solution with a concentration of 1 % [bath ratio(solution : yarn) = 10:1] at 95 °C for 30 minutes. Retention of yarn strength after reduction of sea component = Yarn strength after reduction of sea component Yarn strength before reduction of sea component Herein yarn strength mean tenacity(g/d) of yarn BRIEF DESCRIPTION OF THE DRAWINGS The above objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic view of a process of the present invention Fig. 2 is a graph illustrating viscoelastic properties of the yarn according to the present invention Fig. 3 is a graph illustrating thermal properties (differential scanning thermal analysis) of a yarn according to the present invention Fig. 4 is a graph illustrating the correlation between the melt viscosity and shear rate for each component constituting a sea-island type composite fiber according to the present invention; and Fig. 5 is a graph illustrating a change in the difference (ΔMV) in melt viscosity between a sea component and an island component according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, the present invention will be described in more detail through examples and comparative examples, but it is not limited thereto. Examples 1 through 3 and Comparative Examples 1 through 3 Alkali soluble polymer is prepared by blending polyethyleneglycol of 8 weight% having a number average molecular weight of 8,500 with copolymer polyester in which dimethyl-5-isophthalate sodium of 4 mole% is copolymer. The prepared alkali soluble polymer is used as a sea component and polyethylene terephthalate having an intrinsic viscosity of 0.65 is used as an island component. They are spun by a conjugated spinning spinneret having 36 island components at 288 °C. Continuously, the spun yarn is drawn between a the first Godet roller of 80 °C and the second Godet roller of 125°C at a draw ratio of 2.9 times. Then, it is wound up at a winding speed of 4,120m/min, thereby preparing a sea-island type composite fiber of 75denier / 24filament. The thermal properties and viscoelastic properties of a spin draft yarn passing through the first Godet roller during spinning are adjusted as in Table 1. A warp knit fabric is prepared by the sea-island type composite fiber of the present invention, and then the sea component is dissolved by processing the sea-island type composite fiber in a sodium hydroxide solution with a concentration of 1wt% at 95°C for 30 minutes, and then raised them, thereby preparing raised warp knit fabric. Table. 2 shows the result of evaluating thermal properties and viscoelastic properties of the sea-island type composite fiber and the raising property of the raised warp knit fabric by the above-described evaluation method. [Table 1 ] preparing conditions - conditions of adjusting thermal properties and viscoelastic properties of spin draft yarn [Table 2] results of evaluation of thermal properties and viscoelastic properties of spin-draw filament (end product) INDUSTRIAL APPLICABILITY The sea-island type composite fiber of the present invention has proper thermal properties and viscoelastic properties, so it is easy to dissolve a sea component and the raising property is good. As a result, the sea-island type composite fiber is very useful as a yarn for a raised warp knit fabric having excellent appearance and touch.

Claims: What is claimed is: 1. A sea-island type composite fiber for a raised warp knit fabric which is prepared by the direct spin, draw method by using alkali soluble copolymer polyester as a sea component and polyester mainly consisting of polyethylene terephthalate of more than 90 mole% as an island component, wherein the composite fiber is characterized in that it satisfies the following thermal properties and viscoelastic properties: - a number of presence of melting point peaks : 4, - a temperature of main melting point peak of sea component[Tms] : 220~235°C, - a temperature of main melting point peak of island component[Tmi] : 245~255°C, - a first transition peak temperature[Tα ] of viscoelastic index (tanδ ) : 120-150 °C and - a viscoelastic index value [tanδ α ] of the first transition peak (δ -peak) : 0.10-0.20. 2. The sea-island type composite fiber of claim 1 , wherein the sub melting point peak temperature [Tms'] of the sea component is 2-10°C higher than the main melting point peak temperature [Tms] of the sea component. 3. The sea-island type composite fiber of claim 1 , wherein the sub melting point peak temperature [Tmi'] of the island component is 2-10°C higher than the main melting point peak temperature [Tmi] of the island component. 4. The sea-island type composite fiber of claim 1 , wherein a second transition peak temperature [Tβ ] of a viscoelastic index (tanδ ) of the composite fiber is -50 - -20 °C . , 5. The sea-island type composite fiber of claim 1 , wherein the viscoelastic index [tanδ β ] value of the second transition peak (β -peak) of the composite fiber is 0.03-0.08. 6. The sea-island type composite fiber of claim 1 , wherein the heat of fusion of an island component crystal is 2-5 times larger than the heat of fusion of a sea component crystal. 7. The sea-island type composite fiber of claim 1 , wherein a retention of yarn strength after dissolving the sea component is more than 82%. 8. A method of preparing a sea-island type composite fiber for a raised warp knit fabric by the direct spin draw method by conjugate-spinning alkali soluble copolymer polyester as a sea component and polyester mainly consisting of polyethylene terephthalate of more than 90 mole% as an island component and then drawing the same while passing the same through a first Godet roller and a second Godet roller, and then wounding up the same, wherein the spin draft yarn on the first Godet roller is characterized in that it has the following thermal properties and viscoelastic properties: - a number of presence of melting point peaks : less than 4, - a second transition peak temperature [Tβ ] of viscoelastic index (tanδ ) : - 60—30 TJ and - a viscoelastic index value [tanδ β ] of a second transition peak(β -peak) : 0.04-0.10. 9. The method of claim 8, wherein the first transition peak of the viscoelastic index[tanδ ] of the spin draft yarn is not present. 10. The method of claim 8, wherein the total heat of fusion (ΔHx) of crystal of the spin draft yarn satisfies the following formula with respect to the total heat of fusion (ΔHy) of crystal of drawn and wound sea-island type composite fiber: 1.1 x ΔHy ≤ ΔHx < 1.5 x ΔHy 11. The method of claim 8, wherein the difference (ΔMVg.ooo) between the melt viscosity of island component polymer and the melt viscosity of sea component polymer at a shear rate of 9,000(1/s) is 20-70% of the difference (ΔMV500) between the melt viscosity of island component and the melt viscosity of sea component at a shear rate of 500(1 is). 12. The method of claim 8, wherein the melt viscosity (MVs) of the sea component at a shear rate of 500-9, 000(1 /s) does not exceed the melt viscosity (MVi) of the island component. 13. The method of claim 8, wherein the difference in melt viscosity (ΔMV) between the sea component and the island component is lower than 1,000 poises. 14. A raised warp knit fabric knitted by using the sea island type composite fiber of claim 1.

Inventors: CHOI YOENG-BEEK, HWANG YOUNG-NAM, YOON JOON-YOUNG, CHOI, YOENG-BEEK, HWANG, YOUNG-NAM, YOON, JOON-YOUNG
Applicants: CHOI YOENG BEEK, HWANG YOUNG NAM, KOLON INC, YOON JOON YOUNG, CHOI, YOENG-BEEK, HWANG, YOUNG-NAM, KOLON INDUSTRIES, INC, YOON, JOON-YOUNG
Application year: 2001
Main classification: D01D5
IPC codes: D01F8