WO2006025682A1

WO2006025682A1 - Manufacturing method of fabric for rubbing lcd device and fabric manufactured thereby

Info

Publication number: WO2006025682A1
Application number: PCT/KR2005/002863
Authority: WO
Inventors: Ju Hwa Song; Soo Jung Kim
Original assignee: Ju Hwa Song; Soo Jung Kim
Priority date: 2004-08-31
Filing date: 2005-08-30
Publication date: 2006-03-09
Also published as: KR20060020272A; KR100657420B1

Abstract

Disclosed is a method for manufacturing a rubbing cloth for liquid crystal displays. The method comprises: knitting a synthetic fiber filament yarn as ground yarn and a synthetic fiber or regenerated fiber yarn as pile yarn into a warp knit, in which the underlapping direction of guide bars for forming a ground stitch portion is the same as the underlapping direction of guide bars for forming piles, and at least three guide bars are used in the knitting; and subjecting the warp knit to scouring and shrinkage, preheat setting, raising, shearing, heat setting and cutting processes. The rubbing cloth manufactured by the method can be manufactured to have uniform piles having fine denier and high density compared to the prior art, can be stably adhered to a rubbing cloth fixing roll while maintaining a shape stability like woven fabrics, and at the same time, shows excellent pile characteristics suitable for a rubbing process.

Description

MANUFACTURING METHOD OF FABRIC FOR RUBBING LCD DEVICE AND FABRIC MANUFACTURED THEREBY

Technical Field

[1] The present invention relates to a method for manufacturing a rubbing cloth for liquid crystal displays, and a cloth manufactured thereby. More particularly, the present invention relates to a method for manufacturing a rubbing cloth for liquid crystal displays, in which the rubbing cloth consists of a synthetic fiber knitted fabric instead of a natural or regenerated fiber woven fabric as used in the prior art, so that the rubbing cloth can be manufactured to have uniform piles having fine denier and high density, can be stably adhered to a rubbing cloth fixing roll while maintaining a shape stability equal to woven fabrics, and at the same time, shows excellent pile char¬ acteristics suitable for a rubbing process, as well as a rubbing cloth manufactured thereby. Background Art

[2] Liquid crystal displays are used for image display in televisions, notebook computers, hand-held phones, etc., and their demand greatly increases. In order for liquid crystal molecules forming the base of the display elements to be aligned in a predetermined direction, rubbing treatment using a cloth is carried out during the alignment process.

[3] As used herein, the term "rubbing" refers to a treatment method for aligning liquid crystal molecules in a predetermined direction by rubbing the surface of an alignment film made of polyimide resin, etc., formed on substrates having liquid crystal molecules sandwiched therebetween, in that direction. As the material of the cloth, a woven cloth having the form of high-density piles is mainly used.

[4] In manufacturing this pile cloth, a velvet woven fabric structure is mainly used in

Japan, etc., and the pile yarns thereof are mainly made of rayon, cotton, acetate, etc.

[5] The problems of rubbing clothes manufactured by the prior method will now be described. The principle of the velvet fabric is disclosed in Korean parent laid-open publication No. 2002-0036656 which uses a fabric as shown in FlG. 1 or 2. The fabric as shown in FlG. 2 is used when spun yarn having high friction coefficient leading to a low possibility of pile coming out is mainly used as a pile yarn 3. The fabric as shown in FlG. 1 includes a yarn having low friction coefficient, such as filament yarn, as a pile yarn, and has piles formed to have double intersections to minimize pile coming out of piles upon the use of finished cloth, and also used mainly in a rubbing cloth where the prevention of pile coming out becomes an important factor. The fabric as shown in FlG. 1 can have increased pile-gripping force, but is in a shape where two bundles of piles at three intersections of warp and weft are lifted when seen in the direction of a warp 1. Thus, the fabric as shown in FlG. 1 will necessarily be disad¬ vantageous compared to the tissue of FlG. 2 in increasing the pile density to the maximum and cannot be regarded as a certainly ideal fabric. Although the fabric as shown in FlG. 2 is not highly unreasonable in the pile density, it of course cannot avoid the fundamental problems of spun yarn, such as the coming out of fluff from applied yarn, and insufficient uniformity.

[6] In the prior art as disclosed in Japanese utility model registration No. 3032820 and

Korean patent laid-open publication No. 2003-0043607, piles performing the rubbing function is mainly made of cotton, rayon, acetate, etc, because these materials have low electrostatic generation and good friction characteristics. However, rayon or cotton cannot be regarded as a surely preferable material in that the smaller the denier per filament and the higher the young's modulus and the less the coming out of fluff, it is more advantageous as the material of rubbing piles.

[7] Despite the fact that a polyester or nylon material has various advantages as rubbing pile yarns in that it can be manufactured into a yarn having relatively low denier per filament and total deniner compared to other yarns while maintaining high strength and uniform denier and has little or no coming out of fluff, its use is avoided due to the shortcoming of static electricity generation.

[8] However, the present inventors have paid attention to the fact that, if the polyester or nylon material is complemented with respect to static electricity and friction charac¬ teristics pointed as problems till now while maintaining the advantages of this material, it can be used as a rubbing material. On the basis of this fact, the present invention has been embodied.

[9] Cloth materials having a pile structure, which have been used in the prior art, include woven warp pile fabrics, such as velvet, terry and towel fabrics, and woven weft pile fabrics, such as corduroy and velveteen fabrics. Among them, the velvet fabric has been most generally used.

[10] In addition to the woven fabrics, knitted pile clothes can be manufactured but will have peculiar elasticity due to the general characteristics of knitted fabrics. Namely, these knitted pile fabrics will not be stable in terms of shape stability necessarily required when the resulting rubbing cloth is attached and wound around a stainless roll. For this reason, the knitted pile fabrics have been out of question.

[11] In fact, in the case of circular knitted fabrics, such as velour, terry and fleece fabrics, it is possible to manufacture knitted fabrics having various pile characteristics but it is not reason to control the elasticity and shape stability of the knitted fabrics. Accordingly, the present inventors have made efforts to develop a knitted pile fabric which can be controlled with respect to elasticity and shape stability. Disclosure of Invention Technical Problem

[12] Therefore, an object of the present invention is to provide a knitted rubbing cloth for liquid crystal displays, which has uniform piles having fine denier and high pile density, and shows good pile characteristics suitable for a rubbing process while maintaining a shape stability equal to woven fabrics.

[13] Another object of the present invention is to provide a rubbing cloth for liquid crystal displays, which is suitable for liquid crystal displays having a large width, and can achieve quality stability.

[14] Still another object of the present invention is to provide a rubbing cloth for liquid crystal displays, which shows a great improvement in productivity and economic efficiency.

[15] Yet another object of the present invention is to provide an efficient manufacturing method of said rubbing cloth. Technical Solution

[16] To achieve the above objects, the present invention provides a method for manu¬ facturing a rubbing cloth for liquid crystal displays, which comprises the step of: knitting a synthetic fiber filament yarn as ground yarn and a synthetic fiber or re¬ generated fiber yarn as pile yarn into a warp knit, in which the underlapping direction of guide bars for forming a ground fabric portion is the same as the underlapping direction of guide bars for forming piles, and at least three guide bars are used in the knitting; and subjecting the warp knit fabric to scouring and shrinkage, preheat setting, raising, shearing, heat setting and cutting processes.

[17] In the inventive method, the warp knit is preferably a tricot.

[18] A tricot machine used in the tricot knitting preferably uses 3 or 4 bars having a

24-36 gauge.

[19] In the present invention, part or all of the ground yarn preferably consists of a polyester high shrinkage yarn having a boiling water shrinkage of 15-40%.

[20] The knitting step is preferably carried out after carbon-containing conductive yarns are arranged in the warp or wale direction at a predetermined interval.

[21] In the present invention, the synthetic filament fiber yarn used as the ground yarn preferably contains at least 50% of polyester.

[22] In the present invention, the pile yarn preferably has a denier per filament of

0.2-2.5.

[23] In the present invention, the ground yarn is preferably a polyester filament fiber of

20-75 denier, and the pile yarn is preferably a filament yarn of 50-100 denier. [24] In the present invention, the warp knit is preferably subjected to antistatic treatment during the heat setting process.

[25] In the present invention, during the heat setting process, the warp knit is preferably impregnated with any one or a mixture of two or more selected from the group consisting of thermosetting resin, polyester resin, polyamide resin, polyurethane resin and polyethylene resin.

[26] The rubbing cloth according to the present invention preferably has a pile length of

1.7-3.5 mm.

[27] In the present invention, the specific pile density of the rubbing cloth is preferably more than 0.18, and the number of filaments in the filament fiber for forming the piles of the rubbing cloth is preferably more than 180,000/in . As used herein, the term "specific pile density" (cover factor) is a coefficient established by the inventors in order to compare the relative density value of the pile portion, and is expressed as the following equation:

[28] Wales per inch (WPI) in ground fabric portion x courses per inch (CPI) in ground fabric portion x denier of pile yarn/10⁶.

[29] The higher the coefficient, the more dense the pile portion.

Advantageous Effects

[30] The rubbing cloth according to the present invention can be manufactured to have uniform piles of fine denier and high density compared to the prior method, can be adhered to a rubbing cloth fixing roll while maintaining a shape stability similar to that of woven fabrics, and shows excellent pile characteristics suitable for a rubbing process.

[31] Also, the piles of the rubbing cloth are almost vertically upright owing to high pile density, and thus, need not to be previously oriented in, for example, test runs. Moreover, the rubbing cloth can be optionally cut, and thus, it can flexibly cope with the manufacturing of liquid crystal displays with a large width and can achieve quality stability.

[32] In addition, according to the present invention, the method of manufacturing the rubbing cloth having high productivity and economic efficiency for use in manu¬ facturing liquid crystal displays is provided. Brief Description of the Drawings

[33] FlG. 1 is an enlarged schematic view of a velvet rubbing cloth manufactured using filament fiber according to the prior art.

[34] FlG. 2 is an enlarged schematic view of a velvet rubbing cloth manufactured using spun yarn according to the prior art.

[35] FlG. 3 illustrates the stitch of a warp knitted fabric used in the present invention. Best Mode for Carrying Out the Invention

[36] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[37] According to the present invention, warp knitting is used to allow the knitting of fine denier and high-density piles and large underlapping.

[38] Also, the problem of shape stability is solved by carrying out sufficient thermal shrinkage and heat-setting processes after high-density knitting. Moreover, the present invention is characterized in that the underlapping direction of bars for forming a ground fabric is maintained in the same direction as that of bars for forming piles so that the elasticity of the resulting cloth is minimized to overcome the shortcoming of knitted fabrics in terms of shape stability. If opposite-directional underlapping operations are made as in the prior art, there will be problems in that the elasticity of the resulting cloth is not suitable for purpose so that a tension heat-setting process must be carried out, resulting in a necessary reduction in pile density.

[39] Although this warp knitting may be performed by any one of tricot knitting and raschel knitting, the tricot knitting is somewhat advantageous in terms of high-density knitting or productivity.

[40] In the comparison of the prior woven fabric velvet with the inventive tricot knit, an advantage in pile preparation in the present invention relates to pile density. Specifically, the prior art is as shown in FlG. 1 and may have an increase in pile gripping force in terms of fabric, but cannot be regarded as a certainly ideal tissue because it has a shape where two bundles of piles at three intersections of warp and weft are lifted when seen in the direction of weft 1. In the case of the warp knit according to the present invention, as shown in FlG. 3, two bundles of potential cut piles ("a" and "b" in FlG. 3) are formed at each of stitches or loops, so that the inventive warp knit is highly advantageous in forming high-density piles compared to the filament velvet fabric.

[41] Another characteristic of the present invention relates to a material used for the pile portion. Specifically, in the present invention, the material used for the pile portion is limited to filament yarn except for spun yarn, in view of the general properties of tricot knitted fabrics. Examples of this filament yarn for piles, which can be used in the present invention, include not only rayon and acetate used mainly in woven rubbing clothes, but also polyester and nylon, the use of which has been avoided.

[42] In the present invention, the polyester fiber used as the yarn of the ground fabric has many advantages in that it has a relatively high strength and a high uniformity, can maintain denier per filament and total denier at low levels and has little or no coming out of fluff. The problem of its electrostatic property is solved by using synthetic conductive yarn without any effect on the rubbing effect or by performing antistatic treatment in cloth processing.

[43] The ground yarn used in the present invention is preferably a polyester yarn of

20-75 denier, and the pile yarn is preferably a filament fiber of 50-100 denier regardless of the kind of fiber.

[44] In the polyester ground yarn, the total denier of fiber bundles is important. If the total denier is more than 75 denier, an increase in the pile density will be limited. Also, as the polyester ground yarn, a drawn yarn having a boiling water shrinkage of 6-40% is used, in which the higher the boiling water shrinkage, the easier is to increase the pile density, and this adjustable shrinkage characteristic is the advantage of only polyester, which can hardly be seen in other fibers.

[45] General polyester drawn yarn has a boiling water shrinkage of 6-9%, but at this level of shrinkage rate, sufficient thermal shrinkage in a shrinkage process of the cloth does not occur, and thus, the pile density must be previously increased to the maximum in the knitting process. If a low-temperature drawing high-shrinkage yarn having a boiling water shrinkage of 15-20% or a copolymerized high-shrinkage yarn having a boiling water shrinkage adjustable to 15-40% is used as the high shrinkage yarn, there will be an advantage in that it is easier to increase the density of piles. In terms of this shrinkage property, the polyester fiber among filament fibers is most preferably used as the ground yarn. However, the use of false-twisted yarn (textured yarn) in the ground portion (ground fabric) is not preferable because it is disadvantageous in terms of the shape stability of the resulting processed cloth.

[46] For antistatic purpose in rubbing, conductive yarns having a sheath-core form may also be arranged on a portion of the ground yarn at an interval of a few millimeters, and their denier is selected depending on the denier of the ground yarn used. As such conductive yarns, a type where carbon particles are arranged in the circular cross- section of nylon is typical and widely commercialized in Korea and other countries.

[47] As the ground yarn, filament fiber, such as polyamide (P A6 or PA66), acetate (di- or triacetate), rayon (cupra, polynosic), acrylic or polytrimethylene terephthalate fiber, may also be used, but cannot be superior to the polyester fiber in terms of an increase in the pile density, productivity and economic efficiency.

[48] Meanwhile, a high boiling shrinkage as the property of the pile yarn is rather not preferable, and a general polyester drawn yarn having conventional boiling water shrinkage or an acetate or rayon fiber known to be advantageous in terms of friction characteristics may be used as the pile yarn. The denier of the pile yarn is preferably 0.2-2.5 denier per filament, and more preferably 0.5-2.0 denier per filament in terms of showing a suitable bending rigidity while achieving the high density characteristic of piles. For this pile portion, textured yarn may also be used. The textured yarn has both merits and demerits because it is inferior to drawn yarn in bending rigidity but is excellent in the ability to occupy the space of the pile portion due to its peculiar crimp so as to acts to complement the mutual bending rigidity between filaments. Thus, the textured yarn may optionally be used. However, regenerated fibers, such as rayon or acetate, which are used as pile yarn, are somewhat disadvantageous as a yarn for high- density piles, because it is not easy to adjust their denier per filament, and also the denier is 1.5-4 per filament.

[49] Also, as the pile yarn in the present invention, a shaped yarn or a hollow cross- sectional yarn among polyester fibers is preferably used in terms of an increase in the upright property of piles.

[50] The cloth manufacturing process in the present invention may be performed using a tricot or raschel knitting machine among warp knitting machines. However, the tricot knitting machine is advantageous in terms of productivity, the denier of yarn used and texture, and preferably consists of 3-4 bars having a 24-36 gauge. Important here is a fabric structure affecting the properties of yarn, and it is preferable that the lapping of a yarn forming the ground texture be at an interval of one stitch or 2 stitches, and the lapping of a yarn for forming the pile portion is at an interval of 5-9 stitches.

[51] Important here is the lapping direction of ground guide bars and pile guide bars, in which it is the same in the present invention, while opposite to each other in the case of general clothes. The lapping direction of the guide bars determine the shape stability of the resulting processed cloth, and if the underlapping operations are made in the same direction as in the present invention, the resulting cloth will have a very low elasticity, and thus, have a shape stability like woven fabrics only by heat setting in a little elongated state. If the underlapping operations are made in the opposite directions, the resulting cloth will show unnecessary elasticity and will be imparted with shape stability only if the cloth is subjected to high temperature setting in a stretched state, thus running counter to the aim of increasing the density of piles. Regarding the number of the guide bars used, 2 guide bars cannot achieve dense stitches and strong piles even if yarns are knitted in a relatively high density. Thus, at least 3 full threading guide bars must be used.

[52] In the present invention, post-knitting processes consist of processes, including scouring and shrinking, preheat setting, raising and heat setting, followed by cutting into square shapes having a size conforming to the size of liquid crystal screens. In the scouring and shrinking process, oil components and other impurities on a grey cloth are washed out, and necessary shrinkage is obtained by boiling water. In the raising process to raise the designed piles, shearing is carried out to make the pile length uniform and arranged. Then, the heat setting to impart the final shape stability to the cloth is carried out and at the same time, the cloth may also be treated with a com- mercially available antistatic agent to increase an antistatic effect or be impregnated with thermosetting resin of the heat condensing type, polyester resin with high molecular weight, polyamide resin, polyurethane resin, polyethylene resin or a mixture thereof, to increase the bending rigidity of piles. Although the net length of piles except for the ground fabric will vary depending on the extent of raising and shearing, it is preferably less than about 3.5 mm after shearing if the pile yarn has 7 stitches (10/78) interval at a 28 gauge. The pile length can be optionally adjusted by stitches interval of pile yarn and the fine adjustment of cutting length in the shearing process, in which case the net pile length is preferably 1.7-3.5 mm. Also, in the present invention, the specific pile density of the rubbing cloth is preferably at least 0.18, and the number of filaments in the filament fiber for forming the piles is more than 180,000. This density is necessary for the piles to show the force and bending charac¬ teristics as a rubbing cloth. Mode for the Invention

[53] Hereinafter, the present invention will be described in detail by Examples and

Comparative Examples. It is to be understood, however, that these Examples are presented to merely illustrate the present invention and are not construed to limit the scope of the present invention.

[54] Table 1 below summarizes structures or conditions in each of Examples and

Comparative Examples. In Table 1, the denier and filament number of yarn used as a raw material are set forth in the form of, for example, 50/24, which indicates 50 denier/ 24 filaments. Also, in the threading of a warp knitting machine, only partial threading is set forth, and other portions which is not set forth indicate full threading. Also, the coefficient of specific pile density (cover factor) was used in Table 1. As used herein, the term "specific pile density" is a coefficient established by the inventors in order to compare the relative density value of a pile portion, and is expressed as the following equation: Wales per inch (WPI) in ground fabric portion x courses per inch (CPI) in ground fabric portion x denier of pile yarn/10⁶. The higher the coefficient, the more dense the pile portion. Because it is difficult to count the number of piles per unit area in the pile portion, theoretical number of piles was recorded as WPI*CPI*2*filament number of pile yarn bundle. Although the actual number of piles will be somewhat lower than the theoretical number in view of loss in the raising process, this difference was disregarded because Examples and Comparative Examples have equal conditions.

[55] Specific pile density = GWPI x GCPI x denier of pile yarn/10⁶, wherein GWPI = wales per inch (WPI) in ground fabric portion, and GCPI = courses per inch (CPI) in ground fabric portion.

[56] Examples [57] Example 1

[58] As shown in Table 1, 4 guide bars (Ll, L2, L3 and L4) in a 28G tricot machine were used. For the first ground bar, 60/6 sheath-core-type nylon conductive yarn was arranged in a structure of 10/12 by a partial threading of 1-in 10-out in a warp stripe. For the second ground bar, 50/24 SD polyester filament yarn was arranged in a structure of 10/23. For the third ground bar, 50/24 SD polyester filament yarn was arranged in a structure of 10/12, and for the fourth pile bar, 75/72 SD polyester filament fiber was arranged in a structure of 10/89, thus manufacturing a knitted grey cloth having a density of 34. Then, the cloth was scoured and shrunk, pre-set at 170 °C, raised and sheared. Then, the cloth was subjected to a heat setting process where it was impregnated with a polyurethane resin having a potential thermosetting property and set in a stretched state of 1% in the warp and weft directions,

[59] Example 2

[60] 3 guide bars were used in 28G tricot machine. For the first ground bar, a 30/12 copolymeric high shrinkage polyester filament fiber having a boiling water shrinkage of 18% was arranged in a structure of 10/12. For the second ground bar, the same yarn as in the first bar was arranged in a structure of 10/23 by full threading, and for the third pile bar, 75/39 rayon filament fiber was arranged in a structure of 10/78, thus manufacturing a knitted grey cloth having a density of 39. Then, the cloth was treated in the same manner as in Example 1.

[61] Example 3

[62] In a 32G tricot machine, 4 guide bars and texture were used in the same manner as in Example 1. In each of the first and fourth guide bars, the same yarn as in Example 1 was used, and in the second and third guide bars, the copolymeric yarn having a boiling water shrinkage of 18% as described in Example 2 was used. Thus, a grey cloth having a density of 38 was manufactured. Then, the cloth was treated in the same manner as in Example 1. Comparative Examples 1-3

[63] The texture and yarn shown in Table 1 were used for each of the guide bars to manufacture knitted fabrics having the shown density. Then, each of the fabrics was subjected to the processes in the same manner as in Example 1.

[64] Table 1

Knitting processes and results in Examples and Comparative Examples

[65]

[66] As can be seen in Table 1, the clothes manufactured in Examples have high pile density and pile characteristics suitable for a rubbing process. The pile fabric having low pile density, as manufactured in Comparative Example 1, has limitation on use as a rubbing cloth due to the force and bending characteristics of piles. The pile fabric in Comparative Example 2 is not suitable in terms of shape stability because it inevitably has elasticity due to the opposite directional underlapping operations. Also, Comparative Example 3 shows that it is difficult to obtain the denseness of a ground stitch portion and the firmness of piles even if high-density pile knitting is conducted using 2 guide bars. Accordingly, it can be seen that the pile fabrics of Comparative Examples all cannot be used as the desired rubbing cloth. Industrial Applicability

[67] As described above, the rubbing cloth according to the present invention can be manufactured to have uniform piles having fine denier and high density compared to the prior art, can be stably adhered to a rubbing cloth fixing roll while maintaining a shape stability like woven fabrics, and at the same time, shows excellent pile charac¬ teristics suitable for a rubbing process.

[68] Also, the piles of the rubbing cloth are almost vertically upright owing to high pile density, and thus, need not to be previously oriented in, for example, test runs. Moreover, the rubbing cloth can be optionally cut in the warp direction, and thus, it can flexibly cope with the manufacturing of liquid crystal displays with a large width and can achieve quality stability.

[69] In addition, according to the present invention, the method of manufacturing the rubbing cloth having high productivity and economic efficiency for use in manu¬ facturing liquid crystal displays is provided.

[70]

[71]

Claims

[I] L A method for manufacturing a rubbing cloth for liquid crystal displays, which comprises: knitting a synthetic fiber filament yarn as ground yarn and a synthetic fiber or re¬ generated fiber yarn as pile yarn into a warp knit, in which the underlapping direction of guide bars for forming a ground stitch portion is the same as the un¬ derlapping direction of guide bars for forming piles, and at least three guide bars are used in the knitting; and subjecting the warp knit fabric to scouring and shrinkage, preheat setting, raising, shearing, heat setting and cutting processes.

[2] The method of Claim 1, wherein the warp knit is a tricot.

[3] The method of Claim 2, wherein the tricot machine used in the tricot knitting uses 3 or 4 bars having a 24-36 gauge.

[4] The method of Claim 2, wherein, in the tricot knitting, the lapping of yarn for forming the ground texture is at an interval of one stitch, and the lapping of yarn for forming the piles is at an interval of 5-9 stitches.

[5] The method of Claim 1, wherein part or all of the ground yarn consists of a polyester high shrinkage yarn having a boiling water shrinkage of 15-40%.

[6] The method of Claim 1, wherein the ground yarn contains at least 50% of polyester yarn.

[7] The method of Claim 1, wherein the ground yarn is a polyester filament fiber of

20-75 denier, and the pile yarn is a filament yarn of 50-100 denier.

[8] The method of Claim 1, wherein, in the knitting step, a conductive yarn containing carbon is arranged and knitted at a predetermined interval in the warp or weft direction.

[9] The method of Claim 1, wherein the pile yarn is polyester fiber.

[10] The method of Claim 9, wherein the polyester fiber is shaped yarn or hollow cross-sectional yarn.

[II] The method of Claim 1, wherein the pile yarn has a denier per filament of 0.2-2.5

[12] The method of Claim 1, wherein, in the heat setting process, the warp knit is subjected to antistatic treatment.

[13] The method of Claim 1, wherein, in the heat setting process, the warp knit is im¬ pregnated with any one or a mixture of two or more selected from the group consisting of thermosetting resin of the heat condensing type, polyester resin with high molecular weight, polyamide resin, polyurethane resin and polyethylene resin. [14] A rubbing cloth for liquid crystal displays, manufactured by any one of Claims 1 to 13. [15] The rubbing cloth of Claim 14, wherein the specific pile density of the cloth is more than 0.18, and the number of filaments in the filament fiber for forming the piles is more than 180,000/in .