WO2008056584A1

WO2008056584A1 - Rubbing cloth

Info

Publication number: WO2008056584A1
Application number: PCT/JP2007/071228
Authority: WO
Inventors: Shonan Hata; Masashi Adachi
Original assignee: Kuraray Trading Co., Ltd.
Priority date: 2006-11-07
Filing date: 2007-10-31
Publication date: 2008-05-15
Also published as: KR101494018B1; JPWO2008056584A1; TW200827503A; CN101611344A; JP5009300B2; KR20090079210A; TWI393811B

Abstract

A rubbing cloth for use in alignment treatment of an alignment film of liquid crystal display apparatus, characterized in that the rubbing cloth consists of a ground fabric and pile yarns, and that a heat-fusible composite fiber is used in at least some of warp and weft yarns of the ground fabric, and that the pile yarns consist of flat ultrafine fibers of 1.1 dtex or less obtained by splitting of a multilayer laminated conjugate fiber wherein the flatness (ratio of major axis/minor axis) is 4 or higher. Accordingly, there is provided a rubbing cloth that can form uniform fine channels on the alignment film for liquid crystal display apparatus, being easy in handling thereof.

Description

Specification

Rubbing cloth

Technical field

The present invention relates to a rubbing cloth used in a rubbing process for controlling the alignment of liquid crystal molecules in a manufacturing process of a liquid crystal display device.

Background art

In a liquid crystal display device, the alignment of liquid crystal molecules is regulated by forming fine grooves in an alignment film and aligning liquid crystal molecules along the fine grooves. The process of forming fine grooves in the alignment film is called a rubbing process because the alignment film is rubbed with a pile cloth adhered to a rotating roll. The pile cloth used here is called a rubbing cloth, and as a material, rayon, cotton or the like is currently used.

[0003] A rayon rubbing cloth is a velvet fabric using cupra rayon as ground yarn and normal rayon as pile yarn. After weaving, shearing, desizing and scouring are performed, and then resin processing is performed using a fibre-reactive resin to ensure the stability of the noil. Coated on the back with acrylic resin!

[0004] On the other hand, in the case of a cotton cloth, scouring and bleaching are performed in order to remove wax components and interstices contained in the cotton itself after weaving, and further split shearing is performed. In the case of cotton, the single fiber has a twist called convolution and is not a straight hair, so resin processing with a fibrin-reactive resin is not performed to stabilize the pile. In general, rayon is called a W pile, and it is pressed so that the pile is sandwiched between three wefts. The structure is easy to drop off, and a sufficient back coat is required.

[0005] In general, in the rubbing treatment using a normal rayon or cotton rubbing cloth, the friction force against the alignment film is not uniform unless the length, inclination angle and density of the rubbing cloth pile are uniform. This causes variations in the orientation force of the liquid crystal display and causes the display quality of the liquid crystal panel to deteriorate. In the case of piles made of ordinary ultra fine fibers, the impact resilience is low. And the orientation becomes insufficient due to insufficient frictional force.

[0006] Further, since the rubbing process rubs the alignment film with a high-speed rotating rubbing roller, friction, contact, and peeling are repeated, and static electricity is generated.

This static electricity damages the circuit on the glass substrate and leads to defective LCD displays. In addition, the rubbing cloth is attached to a metal roll with double-sided tape. If the ground of the pile fabric is cellulosic, it expands and contracts due to humidity. That is, it expands at high humidity and contracts at low humidity. For this reason, there is a problem that strict humidity control must be performed for precision cutting, storage, and sticking of the rubbing cloth to the rubbing roll.

[0007] On the other hand, for the purpose of improving the accuracy of liquid crystal display, it has been proposed to use a rubbing cloth having raised portions made of ultrafine fibers of 1. l dtex or less (see Patent Document 1). However, the ultrafine fiber specifically described in Patent Document 1 is an ultrafine fiber having a fan-shaped cross-section by splitting a composite spun fiber having a hollow radial cross-section, and the present inventors When the same ultrafine fiber was used for rubbing treatment, it was found that many orientation defects occurred. The reason for this is that in the ultrafine fibers described in Patent Document 1, the ultrafine fibers that make up the pile easily fall over, and as a result, the advantages of using the ultrafine fibers despite being ultrafine fibers. It is conceivable that sex is made use of! / ,!

[0008] In the rubbing process, friction, contact, and peeling are repeated between the rubbing cloth that rotates at high speed and the alignment film, static electricity is generated, and the circuit on the glass substrate is damaged, resulting in generation of defective liquid crystal displays. Leads to. In order to prevent this, Patent Document 1 discloses that conductivity is imparted to at least the raised layer of the raised cloth in order to prevent charging during the rubbing treatment. As a specific method for imparting antistatic properties, a method of incorporating an antistatic agent such as carbon black or fine metal powder when spinning ultrafine fibers has been proposed. However, when using conductive fibers in which antistatic agents are kneaded into the pile in this way, in the case of velvet fabric or moquette fabric, antistatic materials such as carbon black or metal powder on the surface or cross section of the pile yarn. The agent will be exposed. The rubbing of the alignment film with the pile yarn with the antistatic agent exposed causes contamination and leads to the occurrence of defects in the liquid crystal display device.

[0009] On the other hand, in order to avoid generation of fine dust 'foreign matter due to the abrasion of the conductive material, the sheath / core structure is made of a conductive material and a non-conductive material covering the core. of A rubbing cloth has been proposed (see Patent Document 2), which includes a composite fiber, and the conductive material is substantially exposed on the rubbing surface.

As a specific embodiment, the pile yarn also becomes a composite fiber force of the above-described sheath / core structure, and the pile is cut to form a ring pile! Being! / However, the rubbing cloth described in Patent Document 2 uses a sheath / core conductive composite fiber for the pile yarn, so that the pile yarn cannot be made very thin, and the alignment film can be finely oriented. Have difficulty. In other words, the conductive composite fiber having a sheath / core structure is composed of a metal fiber, a surface metallized fiber, a carbon fiber, a conductive ceramic fiber, or the like as a core conductive material, or a carbon powder, a metal. Conductive powder such as powder is kneaded into a resin and formed into a fiber that is spun, and the entire outer layer is coated with a coating material made of resin such as polyester, acrylic, polyamide, etc. Properties The single fiber fineness of the composite fiber is about 5 to 20 dtex, and it is difficult to obtain one with a fineness, and the pile fineness of the normal rubbing cloth (1.;! To 3.3 dtex) is significantly thicker. In partial use, it leads to rubbing spots and streaks, and in full use, an unequal electric field is not formed and corona discharge cannot be obtained.

In addition, since the tip of the pile yarn is not a sharp angle but a ring pile, the rubbing effect is also reduced. Furthermore, when the conductive material is black, it has been proposed to provide a concealing layer that conceals black and turns white or grayish white!

[0010] Further, Patent Document 1 describes that a vinyl acetate-based or acrylic acid-based resin is coated on the back surface to prevent the pile portion of the rubbing cloth from falling off. If a process is added, the manufacturing process of the entire rubbing cloth will be lengthened, and the cost will increase accordingly, and processing defects such as dirt in the process will increase. Thus, conventionally, rubbing that can improve the accuracy of liquid crystal display A rubbing cloth that can solve problems such as highly effective pile structure with high fineness, contamination with conductive agents, and high costs has been proposed!

[0011] Patent Document 1: Japanese Patent Laid-Open No. 2005_91899

Patent Document 2: JP 2007-232938 Koyuki Disclosure of the invention

[0012] The present invention has been made in view of the above circumstances, and is composed of ultrafine fibers having a special cross-section that eliminates the problem that the length, inclination angle, and uniformity of the density of the yarn yarn are problems. It provides an excellent rubbing cloth that realizes fine and uniform orientation with a pile yarn that has less contamination and eliminates the coating process despite measures against static electricity by conductive fibers. It is for the purpose.

As a result of intensive research to solve the above-mentioned problems, the present inventors can obtain a display element with very little orientation failure by using extra fine fibers with a special cross section for a pile of a rubbing cloth, and further heat It has been found that the use of a fusible conjugate fiber makes it possible to omit the ground backing process, and that a rubbing cloth with improved yield can be obtained by using a conductive conjugate fiber in which the conductive layer is not exposed. The present invention has been completed.

[0013] That is, the present invention is (1) a rubbing cloth used for aligning an alignment film of a liquid crystal display device, the rubbing cloth comprising a ground ground and a pile thread, and the warp of the ground ground A heat-fusible conjugate fiber is used for at least a part of the weft yarn, and the pile yarn is obtained by dividing a multilayer laminated conjugate fiber. 1. A flat ultrafine fiber of 1 ldtex or less, and its flatness ratio ( A rubbing cloth characterized by being composed of ultrafine fibers with a ratio of major axis / minor axis) of 4 or more! (2) The ground ground contains conductive composite fibers, and the conductive The rubbing cloth according to 1 above, wherein the composite fiber has no conductive layer exposed on the fiber surface, and the conductive performance is 10 ⁵ to 10 ⁹ Q / cm per filament, and (3) the conductivity of the conductive composite fiber. Conductive conjugate fibers with a concealing polymer layer on the outer periphery of the layer are used! /, Wherein (2) rubbing cloth according, there is provided a.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of an example of a multilayer laminated composite fiber used as a flat ultrafine fiber forming component of a pile yarn of a rubbing cloth of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the rubbing cloth of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of a conductive conjugate fiber used in the present invention.

FIG. 4 is a schematic cross-sectional view showing a conductive conjugate fiber used in a comparative example of the present invention. Explanation of symbols

[0015] A: Fiber-forming polymer A

B: Fiber-forming polymer B that is incompatible with polymer A

1: Multi-layer laminated composite fiber

10: Rubbing cloth

21: Pile layer

22: Ground

23: Conductive composite fiber

30, 40: Conductive composite fiber

31: Conductive layer

32: Hidden polymer layer

33: Protective polymer layer

41: Protective polymer layer

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] The rubbing cloth of the present invention has an extra fine fiber force used for the pile of the rubbing cloth. As shown in Fig. 1, a fiber-forming polymer (in the present invention, "polymer" is synonymous with "polymer") A, Polymer A is a flat ultrafine fiber obtained by dividing a multi-layered split type composite fiber having a special cross-sectional shape, which is an assembly of flat ultrafine fiber forming components composed of an incompatible fiber-forming polymer B After splitting, each becomes a flat ultrafine fiber made of polymer A or polymer B. The flat fiber has a single fiber fineness of 1. ldtex or less is suitable in that a uniform display element without streaks can be obtained, and 0.;! ~ 1. ldtex is preferred 0.2 ~ 0 A range of 5 dtex is more preferred. Further, the flatness, which is the ratio of the major axis / minor axis in the cross section of the flat ultrafine fiber, is required to obtain a fine groove, preferably 5 or more and 15 or less. It is. In particular, when the pile is formed in a state where the flatness is 4 or more and the flat surface is in contact with the pile, an alignment film having excellent orientation that makes the pile yarn difficult to fall down can be obtained. In order to make the pile yarn formed of flat ultrafine fibers fall down, it is preferable to arrange the pile yarn so that the long diameter side of the flat surface of the flat ultrafine fibers is parallel to the rubbing direction. For example, as a split-type conjugate fiber, a multilayer laminated conjugate fiber as shown in Fig. 1 As a pile forming yarn made of the same fiber (hereinafter also referred to as “pile yarn”), a low twist yarn having a twist number of 0 to 500 T / M is used, and such a pile yarn is parallel to the warp yarn. When driven into the woven fabric, it is pressed against the weft, the pile yarn is flattened, and the flat surface (longer diameter side) of the split multi-layer laminated composite fiber tends to be parallel to the weft. When such a yarn is divided and wound as a rubbing cloth so that the circumferential direction of the labinda roll is the warp direction, the flat surface of the flat ultrafine fiber tends to be parallel to the rubbing direction. Of course, even if no special consideration is given so that the flat surface of the flat ultrafine fiber is parallel to the rubbing direction, the force of the flat ultrafine fiber will naturally be parallel to the rubbing direction. The facing flat ultrafine fibers work effectively and form uniform fine grooves.

[0017] Further, in the present invention, the multilayer laminated composite fiber before division is such that 5 to 20 layers, particularly 7 to 15 layers of flat ultrafine fiber-forming components are laminated so that the flat surfaces are in contact with each other. The cross-sectional shape is preferable and the single fiber fineness of the multilayer laminated composite fiber before division is preferably from !! to lOdtex. As the multi-layer laminated composite fiber before splitting, a cross-sectional shape in which many flat cross-section fiber forming components as described above are in contact with each other in a flat surface is preferable.In particular, the cross-section of each flat ultra fine fiber forming component is almost rectangular. This is preferred in terms of producing fine grooves.

[0018] Further, the pile has a tota nore fineness of 40 to 500 dtex force S, and if the pile height is 1 · 0–3. Omm, especially 1 · 5 to 2.6 · mm, thenoire force is difficult to reach. , Which is preferable in that an alignment film excellent in the life of a selfish person can be obtained. Further, the pile density is preferably such that there are 100,000 to 400,000 piles per lcm ^{2 of} ground fabric.

[0019] Such flat ultrafine fibers are obtained by multi-spinning by introducing two or more incompatible polymers into the spinneret hole so as to be in a multi-layered state when viewed in the cross section of the fiber and performing composite spinning. After the laminated composite fiber is in the fiber state or made into a pile fabric using the fiber, it is treated with stagnation, water jet treatment, air jet treatment, needle treatment, shearing treatment, alkali weight loss treatment, benzoic acid or It can be obtained by splitting with a solvent such as zircanol.

[0020] The incompatible polymer constituting the split-type composite fiber is a polymer having a solubility parameter different by 2 Mj / m-3 or more. Specifically, as the polymer A, polyethylene terephthalate, polybutylene terephthalate or a copolymer polyester mainly composed of these, polylactic acid Poriesutenore etc., nylon 6 as the polymer B, nylon 66, nylon 610, a polyamide, such as semi-aromatic polyamide, or an ethylene Bulle alcohol copolymer of ethylene content from 20 to 50 mole ^_0/0 as the polymer A, polymer B It is preferable because it is easy to divide! It is formed by combining two or more kinds selected from polyolefins such as polyethylene and polypropylene.

The weight ratio of polymer A to polymer B is preferably in the range of 4 ::! To 1: 4, more preferably in the range of 3 ::! To 1: 3.

[0021] More preferred polymers for forming multilayer laminated composite fibers! / Specific examples of combinations include polyamide / polyester, polyester / ethylene-butyl alcohol copolymer, polyester / polyolefin, polyamide / polyolefin, etc. Can be mentioned. Of these, a polyamide / polyester combination is most preferable. The solubility parameter of the polymer composing the composite fiber here is a list of the polymer parameters described on page 90 of the “Plastic Data Book” (issued December 1, 1999) published by the Industrial Research Council. (SP value table) means! / As shown in the SP value table, the solubility parameter can be determined from the calculated value of the density of cohesive energy.

[0022] Next, the heat-fusible composite fiber used for the ground of the rubbing cloth of the present invention will be described. The heat-fusible conjugate fiber used in the present invention is a low melting point component containing a polymer having a melting point of 160 ° C. or lower and 80 ° C. or higher, and a polymer having a higher melting point than the low melting point component. , Composed of two different polymers with high melting point components of melting point 200 ° C or higher, preferably melting point 240 ° C or higher, side-by-side type, core-sheath type (concentric core-sheath type, eccentric core-sheath type), A composite fiber having a composite cross-sectional structure such as a sea-island type or a multi-layer laminate type can be used, and a core-sheath type is particularly preferable.

[0023] Examples of the polymer that can be used for these heat-fusible composite fibers include polyamides represented by nylon and the like, polyesters, and polyolefin polymers represented by polypropylene and polyethylene. Among these, combinations of low melting point components and high melting point components include, for example, low melting point polyester / high melting point polyester, polyethylene / polypropylene, polyethylene / high melting point polyester, polypropylene / polyester. Tell.

[0024] Further, in the present invention, the heat-fusible conjugate fiber has both heat-fusibility and fiber properties such as strength, elongation, and heat-shrinkability even after fusing. This is very important. Considering that the purpose of use of the composite fiber is to prevent the pile from falling off, and that the pile thread is preferably a polyester / nylon composite fiber, the viewpoint of compatibility between the pile thread and the ground thread Therefore, low melting point polyester / high melting point polyester is preferable. Further, those using polyhexamethylene terephthalate as a low melting point polyester component and using polyethylene terephthalate as a high melting point component are particularly preferable because the texture becomes hard after fusion. The proportion of the low melting point polymer in the heat-fusible conjugate fiber is preferably 20 to 80% by weight.

If the low-melting-point polymer is less than 20% by weight, it is difficult to obtain good heat-fusibility, and if it exceeds 80% by weight, the fiber forming processability such as spinnability and stretchability is deteriorated. .

[0025] The single fiber thickness of the heat-fusible composite fiber is 1 to;! Odtex is preferred! In the present invention, all of the fibers constituting the ground may be heat-fusible conjugate fibers, or the heat-fusible conjugate fibers may be used as part of the fibers constituting the lands. It ’s used! When used as a part of the fibers constituting the lands, 40% by weight or more of all the fibers constituting the ground by arranging them at warp and wefts at predetermined intervals are heat-fusible conjugate fibers. It is preferable for preventing the pile yarn from coming off.

Of course, in the present invention, when it is desired to further remove the pile yarn, acrylic emulsion, polyurethane emulsion, rubber emulsion or latex may be back-coated on the dull fabric.

In the present invention, a conductive conjugate fiber can be used for the ground. In general, the rubbing process is performed by rubbing the alignment film with a rubbing cloth adhered to a rubbing roller that rotates at high speed, so that friction, contact, and peeling are repeated between the alignment film and the rubbing cloth, and static electricity is generated. In addition, it damages the circuit on the glass substrate and adsorbs various dust generated during rubbing.

For this reason, countermeasures against static electricity are extremely important. In the above-mentioned Patent Document 1, as countermeasures against static electricity, It is described that a rubbing cloth having conductivity imparted to the raised layer (that is, the pile portion) is used. As a specific measure, a conductive fiber is added to the raised layer, or when a fine fiber is spun. It describes that an electric agent (carbon black or metal powder) is kneaded and spun. However, when the conductive fiber contained in the raised layer is not an ultrafine fiber, the raised layer, that is, the pile surface, is a mixture of the conductive fiber and the ultrafine fiber, and naturally between the alignment film. Differences in friction force occur, resulting in rubbing spots. On the other hand, in the ultrafine fiber kneaded with the antistatic agent, it is impossible in the production process to use the split ultrafine fiber as, for example, a core-sheath type composite fiber. The fiber is understood to mean an ultrafine fiber in which an antistatic agent is uniformly kneaded. Therefore, in this case, carbon black and metal fine powder are exposed on the surface of the ultrafine fiber. Even if it is assumed that the divided ultrafine fibers are composited, the pile yarn is cut after weaving, so the antistatic agent is exposed on the pile yarn cross section, and the If the alignment film is rubbed with ultrafine fibers from which the electrical agent is exposed, contamination will be caused and the liquid crystal display quality will be reduced.

Since the present inventors can remove static electricity from accumulated static electricity by corona discharge instead of conduction, the conductive fibers need not be used for piles. I found it. Examples of the conductive conjugate fiber include a conjugate fiber in which a conductive layer made of a resin containing conductive carbon (carbon black), which is a general conductive agent used for the fiber, is continuous in the length direction of the fiber. Can be used. Since the neutralization is performed by corona discharge, the electrical resistance of the conductive composite fiber is preferably in the range of 10 ⁵ Q / cm to 10 ⁹ Ω / cm. Such conductive carbon black contained in the conductive layer of the conductive composite fibers having an electrical resistance, 10- ² ~; having a resistivity of 10 ³ Omega 'cm is preferred. The electrical resistance here refers to the electrical resistance at an applied voltage of 1 KV after cutting the fiber to 10 cm, applying a conductive paint (dortite) to the cut surface and fixing the fiber end, and using the end as an electrode. It is the calculated electrical resistance per filament.

In addition, as a conductive agent, carbon powder such as acetylene black, ketjen black, PAN-based carbon, pitch-based carbon, ano-remium, palladium, iron, copper, silver, etc. are used as the conductive carbon (carbon black). Metal powder and fiber, zinc oxide, oxidized There are metal compound powders such as titanium oxide, copper sulfide, and zinc sulfide, and these can be used alone or in combination of two or more.

[0029] When carbon black is used as the conductive agent, the electrical conduction mechanism of the conductive carbon black-containing resin is considered to be due to the contact of the carbon black chain, due to the tunnel effect, or the like. It is considered the Lord. Therefore, the longer the carbon chain, and the higher the density of the carbon chain present in the resin, the higher the contact probability and the higher conductivity. As a result of the study by the present inventors, the conductive effect is almost insufficient when the conductive carbon black content is less than 15% by weight, and the conductivity is rapidly improved when the content is 20% by weight, and the conductive effect is almost saturated when the content exceeds 30% by weight. To reach.

The conductive layer of the conductive composite fiber is composed of a conductive material such as conductive carbon black and a fiber-forming polymer.

FIG. 3 shows an example of a cross section of a conductive conjugate fiber including a conductive layer. In the conductive composite fiber 30 used for the rubbing cloth of the present invention shown in the figure, the conductive layer 31 is not exposed on the fiber surface (fiber side surface), that is, the conductive layer 31 is a concealing polymer as a multi-layer nonconductive polymer layer. Covered by layer 32 and protective polymer layer 33, the conductive layer is not exposed on the side of the fiber, it is a sheath-core type conductive composite fiber, and it is non-exposed to avoid the problem of contamination on the alignment film Type.

The thickness of the conductive conjugate fiber used in the rubbing cloth of the present invention is preferably in the range of single fiber fineness of 5 to 2 Odtex, particularly 7 to 18 dtex.

In the rubbing cloth of the present invention, as shown in FIG. 3, a white (gray-white) concealing polymer layer covering the conductive layer in order to conceal the black color of the conductive layer such as carbon black from the viewpoint of aesthetics. It is preferable in view of the appearance of the conductive conjugate fiber. The concealing polymer layer contains inorganic fine particles in a fiber-forming polymer. Examples of the inorganic fine particles include titanium dioxide, zinc oxide, magnesium oxide, aluminum oxide, silicon dioxide, barium sulfate, carbonated potassium, sodium carbonate. White pigments or white fillers having a concealing effect, such as talc and kaolin, which can be used alone or in combination of two or more. Titanium dioxide and / or zinc oxide is preferred in consideration of the concealment effect, whiteness as a fabric, yarn production, and processing characteristics. In the fiber-forming polymer that forms the concealing polymer layer, If the inorganic fine particles are contained in an amount of about 10 to 50% by weight and the thickness of the concealing polymer layer is adjusted, the concealing effect can be obtained. As the fiber-forming polymer, those mentioned later as polymers for forming a sheath layer can be used.

[0032] Further, in the conductive conjugate fiber of the rubbing cloth of the present invention, it is preferable that the concealing polymer layer is further coated with a fiber-forming polymer (polymer) to provide a protective polymer layer. Examples of the polymer forming the protective polymer layer include polyamides represented by nylon and the like, polyesters, and polyolefin polymers represented by polypropylene and polyethylene. In particular, it is preferable to select a polymer having compatibility with the low-melting-point component of the heat-fusible conjugate fiber so that the heat-bonding of the ground can be firmly performed, since the pile yarn can be further removed.

The function of the protective polymer layer is to further protect the conductive layer and the concealing layer, to woven into a velvet fabric, etc. as a conductive composite fiber, and to develop fiber strength as the ground yarn of the rubbing fabric, the black color of the conductive layer, etc. For further concealment. In addition, since the protective polymer layer becomes the outermost surface of the fiber, it is preferable to add titanium dioxide or the like used for ordinary synthetic fibers to the forming polymer to enhance the texture of the fiber. In addition, various additives such as a heat stabilizer, a light stabilizer, and an antistatic agent that are usually used for adding fibers, a color pigment, and the like can be appropriately added to the concealing polymer layer and the protective polymer layer as necessary.

[0033] When the conductive composite fiber is formed of three layers as shown in Fig. 3, the composite ratio in the fiber cross section is set to the maximum thickness of each of the conductive polymer layer 31, the concealing polymer layer 32, and the protective polymer layer 33. Relative specific force The ratio of the conductive polymer layer 31 to 1 is 0.1: 1 to; 1: 0.5 to 2 in terms of conductivity, concealment, surface protection and fiber performance. It is preferable from the balance.

For reference, an exposed type conductive composite fiber is shown in Fig. 4. The conductive composite fiber 40 shown in the figure includes a conductive layer 31 and a protective layer 41, and the conductive layer 31 is exposed at a part of the side surface of the fiber. When such an exposed type conductive composite fiber is used, there is a risk of contamination of the conductive agent due to friction caused by a rubbing roll rotating at high speed.

In the present invention, the conductive conjugate fiber is used as a part of a ground yarn that is not used as a pile yarn. However, contamination is considered in consideration of friction caused by a labinda roll that rotates at high speed. From the point of view of prevention, the non-exposed sheath-core type conductive composite fiber as shown in Fig. 3 is used.

[0034] It is preferable to use 2 to 6 conductive fibers in a bundled state in order to prevent loss of conductivity due to cutting of the conductive composite fibers. In addition, it is also preferable that the conductive conjugate fiber is not subjected to tension as much as possible as a covering yarn in which the conductive conjugate fiber is wound around the non-conductive yarn.

[0035] The conductive conjugate fiber is used in at least the longitudinal direction or the weft direction of the ground texture.

As described above, the yarn containing the conductive conjugate fiber is bundled into a bundle (hereinafter, sometimes referred to as “conductive yarn”), and the distance between lcm and 5 cm of the ground is more preferable. It is used with about 1 lcm to 4 cm. Weaving into the ground structure can be performed using conductive yarns made of only conductive composite fibers, or can be integrated with other reinforcing fibers using means such as interlacing. As described above, it may be a covering yarn. It is convenient to weave in the warp direction or the weft direction at a rate of one conductive thread between lcm and 5cm. When the weaving interval of the conductive yarn is less than 1 cm, the conductive composite fiber is expensive, so that the cost is high and the static elimination performance is not particularly improved. On the other hand, when the weaving interval is 5 cm or more, a sufficient static elimination effect cannot be obtained.

[0036] In the rubbing cloth of the present invention, it is preferable that the ground ground has a weave density of 15 to 40 warps / cm and 20 to 50 wefts / cm. The thickness of the warp and weft is preferably in the range of 50 to 300 dtex.

Next, the best mode of the rubbing cloth of the present invention will be described. FIG. 2 shows an enlarged schematic sectional view of a rubbing cloth 10 according to an embodiment of the present invention.

The rubbing cloth 10 is a pile cloth material made up of a pile 21 and a ground material 22, and a part of the ground material 22 is thermally fused to at least one of the conductive composite fiber 23 and at least! Wearable conjugate fiber is woven. In addition, the pile yarn is a flat ultrafine fiber made of a multi-layered laminated fiber having a flatness of not less than 1. ldtex and a flatness force after splitting, preferably 5 or more. 1. Thickness exceeding ldtex has a large effect on the alignment film of the liquid crystal display element during the rubbing process, and the pile length and tilt angle are problematic, and it is difficult to obtain a uniform alignment effect. [0038] As the pile fabric material, velvet, moquette and the like are suitable. Usually, there are no restrictions on the ground yarn, except that the conductive fabric is disposed at least in the warp direction or part of the weft direction, and at least a heat-sealable composite fiber is used for the warp or weft. The materials used can be used. However, when the ground yarn is cubra, there is a dimensional change due to humidity change, so strict humidity control is required for storage, precision cutting, and sticking to the rubbing tape. Since the required temperature and humidity control is easy, dimensional stability against temperature and humidity and polyester fiber are particularly suitable.

[0039] Since the pile yarn of the rubbing cloth of the present invention has a special cross section made of flat ultrafine fibers, uniform and stable rubbing treatment can be performed. According to this rubbing cloth, it is easy to handle, and it is possible to generate uniform and fine grooves in the alignment film without the need to strictly manage the pile length and the inclination angle as in the past.

[0040] Furthermore, since the rubbing cloth of the present invention has conductive composite fibers arranged in a part of the ground structure, static electricity due to repeated friction, contact, and peeling between the alignment film and the rubbing cloth that occurs during rubbing is prevented. Static electricity can be eliminated by corona discharge, reducing damage to the circuits provided in the alignment film and reducing dust adsorption caused by rubbing.

[0041] When a heat-fusible conjugate fiber is used for at least the warp or weft of the rubbing cloth of the present invention, the back coating for preventing the pile yarn from falling off can be omitted, and the process can be shortened to reduce the cost. And the yield is also improved.

[0042] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

The flatness referred to in the present invention is a mean value obtained by taking a photomicrograph of a cross section of a fiber and enlarging it to obtain the ratio of the long side to the short side for each of 50 arbitrarily selected fibers. Say.

Example

Next, the power to explain the present invention in more detail with reference to examples The present invention is not limited to these examples.

[0044] Example 1

Using the pile yarn, warp and weft described below, the ground weave density is warp and weft 70 / inch (28 / cm) and 69 / inch (27 / cm) velvet fabrics were center-cut and scraped.

[0045] Pile yarn

Polymer A as shown in Fig. 1 obtained by composite spinning using polyester (dissolution parameter = 22 Mj / m ³ ) and nylon (dissolution parameter = 27 M j / m ³ ) in a weight ratio of 2: 1. Polyester of polymer layer and nylon of layer B alternately laminated in 11 layers of multi-layered laminates in the transverse direction. (84 dtex / 24 filament) was used as a flat extra fine fiber forming pile yarn, which was driven in parallel with the warp.

[0046] Grand warp

(1) Regular polyester (84dtex / 72 filament, twisted number S800T / M) As the conductive composite fiber as shown in Fig. 3, nylon 6 containing 35% by weight of conductive carbon black as the conductive polymer layer 31 is concealed. The polymer layer 32 is made of Nylon 6 containing 50% by weight of titanium dioxide fine particles (average particle size 0.2 111), and the protective polymer layer 33 is made of polyester containing 0.5% by weight of titanium dioxide. The composite ratio of the conductive polymer layer and the concealment polymer layer is such that the relative ratio of the longest diameter of the conductive polymer layer and the maximum thickness of the concealment polymer layer and the protection polymer layer is 1: 0.27: 1.03. Conductive composite fiber yarn of 28dtex / 2 filament obtained by composite spinning and drawing with a three-layer core-sheath type composite cross section consisting of a protective polymer layer (electric resistance 3 X 10 ⁷ Q / cm 'f) At the back of the loom at a rate of 1 · 27 cm The yarn is woven into the warp.

[0047] Ground weft

As a weft, a polyhexamethylene terephthalate with a melting point of 135 ° C is used as a low melting sheath component, and polyester is a high melting core component. , Twisted number S500T / M).

[0048] Next! /, Shearing was performed, and desizing, scouring, and splitting of the flat ultrafine fiber-forming pile yarn were performed with an alkali weight reduction process using a sodium hydroxide aqueous solution, with a target weight loss rate of 7%. In addition, after heat treatment at 180 ° C after brushing and drying, the heat-fusible conjugate fiber of the weft is piled up. The pile yarn made of flat ultrafine fibers did not fall off easily from the cut surface cut to the specified size, and the backing process could be omitted. The pile of the obtained rubbing cloth is composed of ultrafine fibers having a fineness of 0.3 dtex and a flatness of 6, the pile length is 2 mm, and the flat ultrafine fibers are in contact with the dividing surface. Existed. In addition, 250,000 flat ultra-thin pile fibers existed per lcm ^{2 of} ground fabric.

[0049] Using this rubbing cloth, rubbing was performed at an indentation length of 0.2 mm and a rotation speed of 1500 rpm, and when the surface state was observed using an atomic force microscope image, uniform and parallel grooves without unevenness were formed. Les In addition, damage to the circuit due to static electricity was reduced, and there were few flaws! / A high-definition liquid crystal display device was obtained.

[0050] << Comparative Example 1 >>

A multifilament yarn (84 dtex / 24 filament) consisting of a composite fiber consisting of 12 layers of polyester / nylon laminated alternately was used as the pile yarn. In this comparative example, the conductive conjugate fiber is not woven into the ground, and the heat-fusible conjugate fiber is not used. Instead, regular polyester fiber (84 dtex / 72 filament, twist S800T / M) is used as the warp and Weft was used for weaving, then shearing was performed, defatting and scouring were performed, and the pile yarn was divided by an alkali weight reduction process using an aqueous sodium hydroxide solution with a target weight loss of 7%. Further, after brushing and drying, back coating was performed with acrylic emulsions to obtain a rubbing cloth.

When rubbing was performed under the same conditions as in Example 1, a sufficient alignment effect could not be obtained. Also, in the backing process, various fabrics and various colors were processed, which was not possible with a machine dedicated to rubbing cloth, so some stains were observed, resulting in poor yield.

In this rubbing cloth, the fiber constituting the pile was an ultrafine fiber of 0.27 dtex, but the average flatness was 1.8.

[0051] <Comparative Example 2>

As shown in Fig. 4, as the conductive composite fiber, nylon 6 containing conductive carbon black is used as conductive layer 31, nylon 6 is also used as protective polymer layer 41, and conductive layer 31 is partially exposed on the fiber surface. The so-called exposed 28dtex / 2 filament conductive composite Fiber 40 (electric resistance 2 X 10 ⁷ Q / cm 'f) and ultra-fine divided fiber with the same radial cross section as in Comparative Example 1 were mixed and used for pile yarn at a rate of 1. Produced a rubbing cloth in the same manner as in Comparative Example 1.

When the rubbing treatment was performed in the same manner as in Example 1, the conductive composite fiber used for the pile was thick as 28 dtex / 2 filament, so scratches occurred, and the conductive composite fiber exposed on the surface of the conductive composite fiber by high-speed rotation. Conductive carbon black dropped from the layer and contamination occurred. The alignment performance deteriorated due to the influence of the cleaning process for removing this, and the quality of the liquid crystal display device deteriorated.

Industrial applicability

The rubbing cloth of the present invention can be used for a uniform and stable rubbing treatment for forming uniform and fine grooves in the alignment film.

In addition, since the rubbing cloth of the present invention uses heat-fusible conjugate fibers at least for the warp or weft, the back coating for preventing the pile yarn from falling off can be omitted, and the rubbing that can improve the yield at low cost. Available for processing.

In addition, the rubbing cloth of the present invention in which conductive composite fibers are arranged on a part of the ground structure eliminates static electricity due to repeated friction, contact, and peeling between the alignment film and the rubbing cloth generated during rubbing by corona discharge and It can be used for rubbing treatment that can reduce damage to the circuit provided on the membrane and reduce the adsorption of dust generated by rubbing.

Claims

The scope of the claims

[1] A rubbing cloth used for orienting an alignment film of a liquid crystal display device, the rubbing cloth comprising a ground and pile yarn, and at least a part of the warp and weft of the ground A heat-sealable composite fiber is used and the pile yarn is obtained by dividing a multilayer laminated composite fiber. 1. Flat ultrafine fiber of Idtex or less, and its flatness ratio (ratio of major axis / minor axis) A rubbing cloth characterized in that it is composed of ultrafine fibers that are 4 or more! /.

[2] The ground ground contains conductive composite fiber, and the conductive composite fiber has no conductive layer exposed on the fiber surface, and the conductive performance is 10 ⁵ to 10 ⁹ Q / cm per filament. The rubbing cloth according to claim 1.

[3] The rubbing cloth according to [2], wherein the conductive composite fiber obtained by applying a concealing polymer layer to the outer periphery of the conductive layer of the conductive composite fiber is used.