JP2005308885A - Rubbing cloth material for manufacturing liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubbing cloth material capable of eliminating adverse effect on the surface of an alignment layer caused by cotton waste and huge time required for removing the cotton waste, hardly generating dimensional change such as elongation of cloth even in a high humidity state and capable of being satisfactorily used for manufacturing a liquid crystal panel. <P>SOLUTION: The rubbing cloth material for manufacturing the liquid crystal panel is a velvet textile having a primary texture structure consisting of the warp 14 and the weft 13 and pile strings 12 woven into the primary texture structure in the warp direction is characterized in that at least one of the warp 14 and the weft 13 is hydrophobic synthetic fiber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubbing cloth material for manufacturing a liquid crystal panel. In the liquid crystal panel manufacturing process, alignment treatment is performed using a rubbing roller in which a rubbing cloth material having a raised pile is attached to the outer peripheral surface of a metal roller with a double-sided adhesive tape. This alignment treatment is a one-way operation on the surface of the alignment film by uniformly rubbing the surface of the alignment film formed on the surfaces of the two substrates constituting the liquid crystal panel with the pile on the surface of the rubbing roller that rotates at high speed. It is the process which provides the molecular orientation of. Such a process is called an alignment process or a rubbing process. The present invention relates to a rubbing cloth material used in a rubbing process essential for manufacturing a liquid crystal panel.

  The rubbing process will be described with reference to FIG. Rubbing is a process in which a cloth material 2 with a pile standing on its surface is attached to the outer peripheral surface of a metal roller 1 with a double-sided adhesive tape, and is rotated on the surface of the substrate 5 constituting the liquid crystal pile while rotating at high speed. This is an operation of rubbing the surface of the alignment film at a high speed with a pile of the cloth material 2. This rubbing step is intended to impart molecular orientation in one direction to the surface of the alignment film. The symbol d in FIG. 3 indicates the indentation depth of the fabric material 2 with respect to the surface of the base material 5, which is commonly referred to as the cut amount. The magnitude of the cut amount d has the strongest influence on the alignment performance.

  A liquid crystal display element used in a transmissive liquid crystal display panel is a TFT substrate on which a driving element (TFT) made of a thin film transistor is formed and a CF substrate on which a color filter (CF) is formed with a small gap therebetween. The liquid crystal is sealed in the gap. An ITO electrode patterned as a pixel electrode is disposed on the surface of the TFT substrate, and an alignment film is formed so as to cover the surface of the ITO electrode.

  The TFT substrate and the CF substrate are arranged so that the alignment films face each other, and the alignment films of both substrates are in contact with the sealed liquid crystal. The alignment film on the TFT substrate surface and the CF substrate surface is subjected to an alignment process using a rubbing cloth material to align liquid crystal molecules. The rubbing cloth material is usually attached to the outer peripheral surface of a roller made of a material such as aluminum or stainless steel via a double-sided adhesive tape. The alignment film surface is rubbed with the rubbing cloth material by bringing the rubbing cloth material on the outer peripheral surface into contact with the alignment film surface while rotating the roller. When such rubbing treatment is performed on the alignment film, ultrafine grooves are formed on the surface of the alignment film itself, or uniaxial alignment is imparted to polyimide molecules that are polymers forming the alignment film. When the liquid crystal comes into contact with the alignment film subjected to the rubbing treatment, liquid crystal molecules are aligned in the direction rubbed with the rubbing cloth material, and uniform switching characteristics of the liquid crystal by the electric field are realized. The performance of liquid crystal alignment by rubbing treatment affects the uniformity of display characteristics that are most important for a liquid crystal panel.

As the rubbing cloth material, a velvet fabric composed of a ground cloth and a pile woven in a raised state on the ground cloth is generally used. As materials for piles, those using long fibers (filaments) such as rayon and nylon and those using short fibers such as cotton are known. As a velvet structure used for the rubbing cloth material, a fast pile velvet fabric as shown in FIG. 1 using cupra rayon for the warp and weft of the fabric structure and viscose rayon for the pile (see Patent Document 1) ) Is common. Further, a V-shaped pile (cut pile) velvet fabric (see Patent Document 2) using cotton as a pile is also used. However, it is not limited to these combinations. For example, even when cotton is used for the pile, it is possible to weave with a fast pile structure. At present, the velvet fabric used as the rubbing cloth material uses cellulosic fibers for the ground yarn, and there is no example using hydrophobic synthetic fibers.
Japanese Patent No. 3209328 Registered Utility Model No. 3045464 Basic Textile Engineering [I] Japan Textile Machinery Society, issued July 30, 1969, P55

  When natural fibers such as cotton are used as the rubbing fabric for at least one of the warp and weft of the fabric, cotton scum such as stems, leaves, and petals that are withered due to natural fibers is usually used as the yarn. Since it cannot be completely removed in the manufacturing process, the cotton scum is woven while being mixed into the yarn. When rubbing using a rubbing cloth with cotton residue remaining on the fabric, the surface of the alignment layer is damaged due to the falling off of the cotton residue on the surface of the alignment layer and the change in the total thickness of the fabric. This will impair the uniformity. In addition, when short fibers such as cotton are used as the ground warp, weaving is reduced due to the occurrence of fuzz and the like compared to long fibers, so there is a limit to the thickness of the thread that can be used as the ground warp, It is difficult to increase the pile density in the warp direction. Further, the elongation with respect to the stress is large, and the elongation is particularly remarkable in the moisture absorption state of the actual liquid crystal panel manufacturing process.

  Furthermore, the rubbing cloth using natural fibers as the base cloth also has a problem regarding dimensional stability. Specifically, there are a problem that the fabric is stretched during the rubbing process and a problem that the dimension after cutting is changed.

  In a liquid crystal display device manufactured using a substrate in which an alignment film is rubbed with a velvet fabric, unevenness in brightness that runs in a direction parallel to the rotation axis of the rubbing roller may occur. As one cause of the occurrence of this unevenness, it has been reported that the velvet fabric is stretched and sagging occurs in the fabric (see Patent Document 1).

  In the liquid crystal panel manufacturing process, in order to prevent electrostatic breakdown of TFT elements, the relative humidity of the atmosphere is often set high (about 60% or more) in order to reduce the generation of static electricity. On the other hand, the rubbing cloth material currently used often uses cupra rayon as the fiber material of the base cloth. Cellulosic fibers such as cupra rayon and viscose rayon are fibers that tend to stretch when the humidity is higher than that of hydrophobic synthetic fibers (Non-Patent Document 1), and the elongation is a problem that is difficult to solve.

  Further, in cutting the rubbing cloth material, it is extremely important to accurately cut at a desired angle with respect to the warp. At present, the fabric is cut on the premise that the wefts intersect at right angles to the warp. However, the fabric using cellulosic fibers in the fabric is scoured without paste and coated with resin on the back of the fabric. In the process finishing process, the fabric is frequently bent. This is particularly noticeable in the portion of the fabric close to both ears. This is considered to be one of the factors that cause the alignment characteristics of the liquid crystal after the rubbing process to vary from lot to lot.

  Furthermore, the rubbing cloth material is wound around the outer periphery of the rubbing roll through a double-sided adhesive tape, and it is a very important element that the cloth of the rubbing cloth material does not change its dimension in the length direction after cutting. In other words, the reduction in dimensions will cause gaps at the joints after being wound around the rubbing roller, and if the dimensions are extended, the joints may overlap and sagging may occur in the fabric. Cause.

  Accordingly, an object of the present invention is to eliminate the adverse effects on the alignment film surface caused by cotton residue and the enormous time required to remove the cotton residue, and it is difficult for the fabric to stretch or change in dimensions even under high humidity conditions. The object of the present invention is to provide a rubbing cloth material that can be used very well in the manufacture of

  The present inventor has found that it is very effective to use a hydrophobic synthetic fiber for at least one of the warp and the weft of the base fabric structure of the rubbing cloth material, and has completed the present invention.

  That is, the present invention is a rubbing cloth material for producing a liquid crystal panel of a velvet fabric, comprising a ground fabric composed of warp and weft, and a pile yarn woven in the warp direction of the fabric. At least one of the wefts is a rubbing cloth material for manufacturing a liquid crystal panel, which is a hydrophobic synthetic fiber.

  In the present invention, by using hydrophobic synthetic fibers for at least one of the warp and weft of the fabric, the adverse effect on the alignment film surface caused by cotton residue and the enormous amount of time required to remove the cotton residue are eliminated. can do.

  Moreover, since the hydrophobic synthetic fiber is difficult to stretch even in a high humidity state, the elongation of the rubbing cloth material in the liquid crystal panel manufacturing process can be reduced. In addition, it is possible to reduce the dimensional variation of the rubbing cloth material after cutting and the occurrence of the cloth bending.

  In the present invention, conventionally known various synthetic fibers can be used as the hydrophobic synthetic fiber used for at least one of the warp and the weft of the fabric. Specifically, for example, polyester fiber, polypropylene fiber, polyamide fiber (nylon fiber, etc.), polyethylene fiber, and the like can be suitably used. Moreover, polyvinyl chloride fiber, vinylidene fiber, vinylon fiber, aramid fiber, etc. can also be used.

  In the present invention, the pile yarn is not particularly limited, and various yarns conventionally known to be usable as a pile yarn can be used. Specifically, for example, viscose rayon, cotton, acetate fiber and the like can be suitably used.

  As the rubbing cloth material of the present invention, a velvet fabric comprising a ground cloth and a pile woven in a raised state on the ground cloth can be used. The pile may be long or short. As a velvet structure used for the rubbing cloth material, a fast pile velvet fabric (12: pile, 13: warp, 14: weft) as shown in FIG. 1 is generally used. Further, a V-shaped pile (cut pile) velvet fabric (12: cut pile, 13: warp, 14: weft) as shown in FIG. 2 using short fibers such as cotton for the pile can also be used. In the present invention, the above-described effects can be obtained by using hydrophobic synthetic fibers for the warp and / or the weft of the velvet fabric.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Examples 1 to 3, Comparative Example 1>
As described below, a rubbing cloth material (velvet fabric) of the present invention using polyester fiber, nylon fiber, and polypropylene fiber as the ground yarn was prepared, and the elongation was measured. These velvet fabrics are all woven with the fabric structure shown in FIG.

In Example 1, as a warp yarn, a polyester fiber of 56 dtex was used as a twisted yarn of 900 T.PM and an upper twist of 600 T.PM, and as a weft yarn, a polyester fiber of 84 dtex was used. The ground warp density was 23 yarns / cm and the ground weft density was 44.5 yarns / cm. As pile yarn, 84 dtex double yarn triacetate processed yarn was used. A velvet fabric having a pile length of 1.8 mm was woven, finished by a normal processing method, and an acrylic resin was coated on the side of the fabric where there was no pile to obtain a rubbing cloth material.
It was.

  In Example 2, as the warp yarn, nylon yarn 56 decitex yarn was used as a twisted yarn of 900 T.P.M. and upper twist 600 T.P.M., and as the weft yarn, 56 dtex nylon fiber was used. The ground warp density was 23 yarns / cm and the ground weft density was 52 yarns / cm. As pile yarn, 84 dtex double yarn triacetate processed yarn was used. A velvet woven fabric having a pile length of 1.8 mm was woven, finished by a normal processing method, and an acrylic resin was coated on the side of the fabric where there was no pile to obtain a rubbing cloth material.

  In Example 3, 750 T.P.M. twisted yarns of 750 T.P.M. and twisted 450 T.P.M. were used as ground warp yarns and 56 dtex polypropylene fibers as weft yarns. The ground warp density was 23 yarns / cm and the ground weft yarn density was 45 yarns / cm. As the pile yarn, 84 dtex triacetate processed yarn was used. A velvet woven fabric having a pile length of 1.8 mm was woven, finished by a normal processing method, and an acrylic resin was coated on the side of the fabric where there was no pile to obtain a rubbing cloth material.

  In Comparative Example 1, a rayon pile velvet fabric currently available for liquid crystal rubbing was prepared. This velvet fabric is said to use viscose rayon 84 dtex for the ground warp and cupra 66 dtex for the weft.

  In the rubbing cloth materials of Examples 1 to 3 and Comparative Example 1 obtained as described above, the piles are arranged in parallel with the ground warp. When the rubbing treatment is performed on the alignment film, it is reported that the rotation direction of the rubbing roller and the angle formed by the warp of the rubbing cloth material are preferably shifted by 3 to 45 degrees (Patent Document 1). .

  About the rubbing cloth material of Examples 1-3 and the comparative example 1, it cut | disconnected in the direction of an angle of 15 degree | times with respect to the warp direction and the warp, and obtained the test piece of width 5cm and length 30cm. In this cutting, the samples of Examples 1 to 3 could be cut with higher accuracy than those of Comparative Example 1. Each test piece was given a tensile stress of 5 kg in a standard state and a moisture absorption state, and the elongation at that time was measured. By this measurement, it is possible to know the elongation (particularly humidity dependence and anisotropy) of the fabric structure. The measurement results are shown in Table 1.

  For the rubbing cloth material using the hydrophobic synthetic fibers of Examples 1 to 3 as the ground yarn, both the standard warp and the hygroscopic elongation (A, B) is small. Moreover, the ratio (B / A) is in the range of 1.02 to 1.09, and the increase in elongation in a moisture absorption state is small. On the other hand, it can be understood that the rubbing cloth material using the cupra of Comparative Example 1 as a ground yarn is easily stretched in a hygroscopic state, and particularly easily stretched by stress when cut in an oblique direction.

  Moreover, if long fibers with good weaving properties such as polyester fibers, nylon fibers, and polypropylene fibers are used for the ground yarn as in Examples 1 to 3, it becomes possible to weave with finer yarns, and the warp density is high. A thicker pile yarn can be used if it is structured or structured with the same warp density.

  In Table 1, the deviation angle from the ground warp is the angle formed by the center line in the length direction of the cut sample piece with respect to the warp direction when the angle parallel to the warp direction is 0 degree. means. Also, the moisture absorption state is a measurement of a cut sample piece immediately after being left in a state of temperature 20 ° C. and humidity 100% for 24 hours and moisture absorption. Further, the standard state means a state defined by a physical test method for textile products of JIS L 0105.

<Example 4>
As Example 4, as a warp yarn, polyester fiber 56 dtex was used as a yarn with a lower twist of 900 T.PM and an upper twist of 600 T.PM, and as a warp yarn, a 84 dtex polyester fiber was used. The ground warp density was 23 yarns / cm and the ground weft density was 45.5 yarns / cm. As the pile yarn, a double yarn of cotton No. 60 comber yarn was used. A velvet fabric having a pile length of 1.8 mm was woven, finished by a normal processing method, and an acrylic resin was coated on the side of the fabric where there was no pile to obtain a rubbing cloth material.

  The dough of Example 4 and Comparative Example 1 was subjected to press cutting using a Thomson blade made of Nakayama Co., Ltd. in a size of 468 mm in the length direction and 1200 mm in the width direction. As a process prior to attaching the rubbing cloth material to the rubbing roller, removal of cotton dust and other solid impurities on the surface of the rubbing cloth and inspection work were performed. as a result. In Example 4, the amount of impurities was reduced as much as possible, and the working time was about one-sixth that of Comparative Example 1, and the work could be greatly rationalized.

It is an organization chart of the velvet fabric of a fast pile. It is the velvet organization chart of the V-shaped pile which used cotton for the pile. It is the figure which showed the state which the rubbing cloth material affixed on the roller contacted the board | substrate.

Explanation of symbols

1 Metal Roller 2 Fabric Material 5 Substrate 12 Pile 13 Warp 14 Weft

Claims (3)

A rubbing cloth material for producing a liquid crystal panel of a velvet woven fabric having a ground fabric structure composed of warps and wefts, and a pile yarn woven in the warp direction of the base fabric structure,
A rubbing cloth material for manufacturing a liquid crystal panel, wherein at least one of the warp and the weft is a hydrophobic synthetic fiber.   The rubbing cloth material for producing a liquid crystal panel according to claim 1, wherein the hydrophobic synthetic fiber is a polyester fiber, a polypropylene fiber, a polyamide fiber, or a polyethylene fiber.   The rubbing cloth material for producing a liquid crystal panel according to claim 1, wherein the hydrophobic synthetic fiber is a polyvinyl chloride fiber, a vinylidene fiber, a vinylon fiber, or an aramid fiber.

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