JP2009015278A - Rubbing cloth for liquid crystal display device, and rubbing device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubbing cloth which has characteristics of high wear resistance, high aligning uniformity and large alignment controllability. <P>SOLUTION: The invention is characterized in that: the rubbing cloth includes a base fabric woven with warp and weft, and pile yarn transplanted to the base fabric and composed of bicomponent fibers of cotton fibers and rayon fibers; and the rubbing device includes a rubbing roll which is rotated with a driving device and the rubbing cloth which is wound around the rubbing roll and rubs an alignment layer of a liquid crystal display device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubbing cloth, and more particularly to a rubbing cloth used in a rubbing process in order to control the orientation of liquid crystal molecules in a liquid crystal display device.

  In general, liquid crystal display devices have features such as low voltage drive, low power consumption, full color realization, lightness, thinness, smallness, etc., such as clocks, computers, PC monitors, laptop computers, etc. It has been applied to various fields.

Such a liquid crystal display device is roughly divided into a liquid crystal display panel for displaying an image and a circuit unit for driving the liquid crystal display panel.
Here, the liquid crystal display panel includes a TFT substrate on which a thin film transistor (TFT) array is formed and a color filter substrate (hereinafter also abbreviated as a CF substrate) on which a color filter array is formed at a minute interval. After being arranged, the liquid crystal is injected between them.

  An ITO electrode patterned as a pixel electrode is formed on the surface of the TFT substrate, and an alignment film is coated on the surface of the ITO electrode. Further, an ITO electrode is positioned as a common electrode on the surface of the CF substrate, and an alignment film is similarly coated on 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 on both substrates are in contact with the liquid crystal.

  In the liquid crystal display device configured as described above, an array process for forming a wiring pattern or a switching element such as a thin film transistor on a glass substrate, an alignment process or an arrangement of spacers and a space between substrates facing each other. It is manufactured by a cell process for sealing liquid crystal and a module process for attaching a driver IC or attaching a backlight.

Here, the cell process includes a rubbing process for inducing liquid crystal alignment, and is performed through a series of steps such as bonding of substrates and injection of liquid crystal. Note that the rubbing process is performed to perform an alignment process on the alignment films of the TFT substrate and the CF substrate.
As an alignment treatment method for the alignment film as described above, a so-called rubbing method is used in which the surface of the alignment film is rubbed mainly with a rubbing cloth.

  Referring to FIG. 1, the rubbing cloth 10 is usually wound around the outer peripheral surface of a rubbing roller 1 made of stainless steel, and the rubbing cloth 10 is brought into contact with the surface of the alignment film 2 while rotating the rubbing roller 1. If the surface of 2 is rubbed, the surface of the alignment film 2 is rubbed.

  In general, the rubbing cloth 10 is manufactured by a raising process in a form in which a pile yarn 11 is planted in a ground fabric structure composed of warp and weft. In the rubbing cloth 10, the pile density is adjusted by changing the thickness of the pile and the thread used for the cloth, and the length of the pile is determined by a cutting method for the cloth.

Here, as the fiber used for the pile yarn 11, those using long fibers such as rayon and nylon and those using short fibers such as cotton are known.
However, when a rayon filament is used as the pile yarn 11, there is a problem that the wear resistance is insufficient. That is, the rubbing cloth having the rayon pile yarn is likely to generate foreign matter due to wear of the pile during the rubbing process, and the foreign matter thus formed causes alignment failure on the surface of the alignment film. Defects such as display unevenness are generated on the screen.

In addition, foreign matters generated due to wear during the rubbing process are likely to remain on the rubbing cloth 10, but when other substrates are rubbed in a state where the foreign matters remain, the surface of the alignment film 2 is damaged, and the liquid crystal This causes a defect such as a vertical line on the screen of the display device.
Further, the damage given as described above causes problems such as a white display of the screen of the liquid crystal display device. Further, a rubbing cloth having a pile yarn with low abrasion resistance has low uniformity in rubbing quality, and therefore, it is necessary to frequently switch in order to prevent occurrence of defects such as uneven display on the liquid crystal display device.

  In addition, in the abrasion resistance of the pile, the rubbing cloth in which the pile yarn 11 is made of cotton is superior to the pile yarn made of rayon. This is because cotton and rayon are both cellulosic fibers, but cotton has a higher molecular weight and higher wear strength than rayon.

However, since cotton is a natural fiber and a short fiber, it must be spun and used, and pile yarn made of cotton is thicker than rayon or nylon. Further, since pile yarn made of cotton is a short fiber, the short fiber is likely to fall off due to friction during the rubbing process.
Furthermore, since cotton is a natural fiber, the quality of the fiber itself varies depending on the production area, production time, etc., and defects such as vertical lines are more likely to occur than long fibers such as rayon and nylon. As described above, the rubbing cloth made of cotton pile yarn is slightly improved in durability as compared with the rubbing cloth made of rayon pile yarn, but the possibility of fiber dropping due to friction during the rubbing process is increased.

  Patent Document 1 discloses a rubbing cloth using an aramid fiber and can improve the abrasion resistance of the pile yarn. However, the aramid fiber has a high degree of crystallinity and an excellent tensile strength. However, the pile yarn has low shear strength. As a result, the pile yarn breaks in the longitudinal direction during the rubbing process, causing a large amount of fibrils to fall off, leading to alignment film defects.

Patent Document 2 describes a method of using a fiber type protein as a rubbing cloth. However, since the fiber type protein is silk or wool, the heat resistance is insufficient. Therefore, a rubbing cloth made of a fiber type protein is easily deformed by frictional heat generated in the rubbing process, and is unsuitable as a rubbing cloth.
JP-A-7-270798 Japanese Patent Laid-Open No. 6-194661

  The present invention is to solve the above-described problems, and an object of the present invention is to provide a rubbing cloth having characteristics of high wear resistance and high degree of orientation uniformity and high orientation regulating force.

  In order to achieve the above object, the present invention provides a rubbing cloth comprising a ground fabric woven with warps and wefts, and a pile yarn planted in the base fabric and made of a composite fiber of cotton fibers and rayon fibers. provide.

  The pile yarn is manufactured by mixing and spinning cotton fiber and rayon fiber at the spinning stage.

Here, the pile yarn is preferably formed using a rayon fiber having a length of 20 mm or more.
More preferably, the length of the rayon fiber is 32 mm to 54 mm.

  Moreover, it is preferable that the mixing rate of a rayon fiber is 25 to 75% with respect to all the pile yarns.

  The pile yarn is woven into a V shape using a composite short fiber of cotton fiber and rayon fiber.

  As another embodiment, the present invention provides a rubbing apparatus including a rubbing roller that is rotated by a driving device, and a rubbing cloth that is wound around the rubbing roller and rubs the alignment film of the liquid crystal display device. Comprises a ground fabric woven with warps and wefts, and a pile yarn planted in the fabric and made of a composite fiber of cotton fibers and rayon fibers.

  According to the rubbing cloth and rubbing apparatus of the present invention described above, the binding force of pile yarns is improved in the substrate rubbing step, and fine rubbing is possible. In addition, the wear resistance and the orientation uniformity are improved, whereby an excellent quality liquid crystal display device can be manufactured.

  According to the rubbing cloth according to the present invention having the pile yarn composed of the cotton fibers and the rayon fibers as described above and the rubbing apparatus having the rubbing cloth, there are the following effects.

First, according to the rubbing cloth and the rubbing apparatus according to the present invention, the short fiber used as the pile yarn is a cotton-rayon composite short fiber, thereby increasing the binding force of the pile yarn in the rubbing process, Rubbing is possible. Further, it is possible to improve the wear resistance and the orientation uniformity, and to manufacture a liquid crystal display device of excellent quality.
Secondly, according to the present invention, since the rubbing cloth switching cycle becomes long, the productivity of the rubbing process is improved, and the process defect rate per rubbing cloth is lowered.

  Hereinafter, preferred embodiments of the present invention capable of specifically realizing the above object will be described in detail with reference to the accompanying drawings. In the description of the present embodiment, the same components are denoted by the same names and the same reference numerals, and the description thereof is omitted.

  The rubbing cloths 100 and 100a used in the rubbing process of the liquid crystal display device have a velvet shape, and are configured in such a manner that pile yarns 130 and 130a are planted on a ground fabric structure composed of warp yarns 110 and weft yarns 120. The warp yarn 110 and the weft yarn 120 are not particularly limited in the fiber material, but generally the same ground yarn as the pile yarns 130 and 130a is used. Here, the warp refers to the yarn in the length direction of the rubbing cloth, and the weft refers to the thread in the width direction of the rubbing cloth.

2 and 3, generally, when weaving a velvet for the rubbing cloth 100, 100a, the pile yarns 130, 130a are woven with a V-shaped structure and a W-shaped structure. It is done.
Here, when short fibers are used as the pile yarns 130 and 130a, small fibers of the pile yarn are likely to be generated by weaving, so when weaving into a V-shaped structure and using long fibers as the pile yarn, It is preferable to weave into a W-shaped structure that can increase the density of the pile yarn and that causes less pile falling off.

In the present invention, as the pile yarns 130 and 130a, a cotton-rayon composite yarn (mixed yarn) formed by mixing cotton fibers 131 and rayon fibers 132, which are natural fibers, is used. Further, the pile yarn is configured to be inclined in the warp direction or the weft direction.
Here, the pile yarns 130 and 130a are manufactured by mixing and spinning cotton fibers and rayon fibers 132 that are semi-synthetic fibers at the spinning stage. FIG. 4 shows rubbing cloths 100 and 100a produced by twisting cotton fibers 131 and rayon fibers 132, and FIG. 5 is an enlarged cross-sectional view of pile yarns 130 and 130a configured as described above. It is shown.

In addition, the cotton fiber 131 which is a natural fiber is not particularly limited in length in a short fiber state, but in the case of a rayon fiber, a fiber cut into a length of 30 mm or more is used.
The length of the rayon fiber 132 is not particularly limited, but it is desirable to use a rayon fiber having a length of 32 to 54 mm. This is because, as a result of the experiment, if the length of the rayon fiber 132 is short, the bundling force is hindered, and if it is long, uniform spinning is difficult at the time of spinning.

  The thickness of the cotton-rayon mixed spun yarn used as the pile yarns 130 and 130a is 20 s' (number) or more. This is because uniform rubbing is difficult if the pile yarns 130 and 130a are too thick.

The mixing ratio of the rayon fibers 132 constituting the pile yarns 130 and 130a is not particularly limited, but is preferably 25% or more and 75% or less with respect to all the pile yarns.
As a result of the experiment, when the mixing ratio of the rayon fibers 132 constituting the pile yarns 130 and 130a is 25% or less with respect to all the pile yarns, the binding force of the pile yarns, the orientation uniformity, the orientation This is because when the regulation power is somewhat lowered and the mixing ratio of the rayon fiber exceeds 75%, the wear resistance is lowered.

  In one embodiment of the present invention, the rubbing cloth is woven using a V-shaped structure by using short fibers as pile yarns for weaving the rubbing cloth.

  Moreover, in the structure of the warp 110 and the weft 120, the short fiber comprised by the cotton independent or the short fiber comprised by the cotton-rayon composite can be used.

  Since the density structure of the base fabric structure is related to the arrangement direction of the piles, in the case of the cotton rubbing cloth, the weft density is higher than the warp density. In the case of using the cotton-rayon composite pile yarns 130 and 130a as in the present invention, there is no particular limitation, but in terms of pile stability, the weft density is set higher than the warp density. Weaving.

The fabric woven as described above undergoes a shaving process to uniformly match the thickness and length. Moreover, the ground fabric prepared in this way arrange | positions a pile through a well-known refining and resin process.
More specifically, after removing the oil agent and paste remaining on the fabric in the washing process, pre-drying is performed, and the subsequent fabric is dipped in the resin in the resin dipping process and cured by heat while the brush device is used. Used to fix the pile in a fixed direction.

  Further, the rubbing cloth manufactured as described above is wound around a cylindrical rubbing roller to constitute a rubbing apparatus, and the substrate alignment film is rubbed by rotating the rubbing apparatus. Here, the rubbing roller is configured to be rotated by a driving device such as a motor.

  Hereinafter, various embodiments of the rubbing cloth according to the present invention and comparative examples will be described. However, the embodiments to be described later merely illustrate the present invention, and the present invention is not limited to the following embodiments.

[Embodiment 1]
The warp yarns 110 and the weft yarns 120 are composed of 40s' short fibers composed of composite short fibers of cotton fibers and rayon fibers, and the pile yarns 130 and 130a are composed of composite short fibers of cotton fibers 131 and rayon fibers 132. 40 s' was used to weave into a V-shape shown in FIG. 2 using a velvet weaving machine so that the warp density was 43 / inch and the weft density was 81 / inch.

Here, rayon short fibers 132 used as pile yarns having a unit length of 52 mm were used, and were manufactured in a composite form in the form shown in FIGS. 4 and 5 in the spinning process.
Further, the pile yarns 130, 130a were used with a rayon staple fiber ratio of 25%. The base fabric of the rubbing cloth woven as described above was dipped in resin, then subjected to raising treatment 10 times in the warp direction and 5 times in the weft direction, and heat-treated at 150 ° C. for 3 minutes with a heat treatment machine.

[Embodiment 2]
40s' short fibers composed of composite short fibers of cotton fibers and rayon fibers are used as the warp yarns 110 and the weft threads 120, and 40s composed of composite short fibers of cotton fibers and rayon fibers as the pile yarns 130 and 130a. Using a velvet weaving machine, weaved into a V shape as shown in FIG. 2 so that the warp density was 43 / inch and the weft density was 81 / inch.

Here, the unit length of the rayon short fiber 132 used for forming the pile yarns 130 and 130a is 52 mm, and the rayon short fiber 132 in the pile yarn has a ratio of 50%. .
The rubbing cloth woven as described above was dipped in resin, then subjected to raising treatment 10 times in the warp direction and 5 times in the weft direction, and heat-treated at 150 ° C. for 3 minutes with a heat treatment machine.

[Embodiment 3]
The warp yarns 110 and the weft yarns 120 are composed of 40s' short fibers composed of composite short fibers of cotton fibers and rayon fibers, and the pile yarns 130 and 130a are composed of composite short fibers of cotton fibers 131 and rayon fibers 132. 40 s ′ was used to weave into a V shape shown in FIG. 2 using a velvet weaving machine so that the warp density was 43 / inch and the weft density was 81 / inch.

Here, the unit length of the rayon short fiber 132 used as the pile yarns 130 and 130a is 52 mm, and the rayon short fiber 132 in the pile yarn has a ratio of 75%.
In addition, the fabric woven as described above was dipped in resin, then subjected to raising treatment 10 times in the warp direction and 5 times in the weft direction, and heat-treated at 150 ° C. for 3 minutes with a heat treatment machine.

[Comparative Example 1]
A known velvet weaving machine using cotton short fibers 40s 'as the warp yarns 110 and weft yarns 120 and cotton short fibers 40s' as the pile yarns, so that the warp density is 43 / inch and the weft density is 81 / inch. Was used to weave into the V-shape shown in FIG.

  The rubbing cloth woven as described above was dipped in resin, then subjected to raising treatment 10 times in the warp direction and 5 times in the weft direction, and heat-treated at 150 ° C. for 3 minutes with a heat treatment machine.

[Comparative Example 2]
A warp fabric is woven using 120 denier of copper ammonia (cuprammonium) as the warp yarn 110 and 75 denier of copper ammonia as the weft yarn 120, and 100 yarns of rayon long fiber as the pile yarns 130 and 130a. Was used to weave into a W-shape as shown in FIG. 3 using a known velvet weaving machine so that the warp density was 60 / inch and the weft density was 122 / inch.

  The fabric woven as described above was dipped in resin, then subjected to raising treatment 10 times in the warp direction and 5 times in the weft direction, and heat-treated at 150 ° C. for 3 minutes with a heat treatment machine.

About embodiment and the comparative example, the characteristic of the rubbing cloth was experimented as follows and the comparative analysis was performed.
Table 1 shows the characteristics of the rubbing cloth, such as rubbing durability, orientation uniformity, and residual hair fall, divided into the embodiment and the comparative example.
* Rubbing durability: An IPS liquid crystal display device was manufactured, and in the rubbing process during the manufacturing process of the liquid crystal display device, the switching cycle of the rubbing cloth according to the quality of the alignment film was measured and evaluated by an average value of 10 times. (Rubbing cloth switching cycle is displayed in number of glasses)
* Alignment uniformity: An IPS liquid crystal display device is manufactured, and the degree of alignment uniformity is evaluated by measuring the defect rate with a rubbing cloth in the manufacturing process of the liquid crystal display device. (Calculate defective rate by rubbing cloth and evaluate orientation uniformity by passing rate of rubbing process)
* Residual hair loss: Manufactures IPS liquid crystal display devices, and measures the degree of occurrence of hair loss remaining in the alignment film in the manufacturing process of liquid crystal display devices.

  As can be seen from the above table, according to the embodiment of the present invention, the durability, the degree of orientation uniformity, and the degree of occurrence of hair loss are all equally superior to those of Comparative Examples 1 and 2.

It will be apparent to those skilled in the art that the present invention can be embodied as other embodiments within the spirit and scope of the present invention in addition to the above-described embodiments.
Accordingly, the above-described embodiments should be considered as illustrative rather than restrictive, and the present invention is not limited to the above-described detailed description, but within the scope of the appended claims and their scope. Various changes can be made within the same range.

It is sectional drawing which showed the general rubbing apparatus. It is the perspective view which showed one Embodiment of the rubbing cloth which concerns on this invention. It is the perspective view which showed other embodiment of the rubbing cloth which concerns on this invention. It is the block diagram which showed the pile thread | yarn of the rubbing cloth which concerns on this invention. It is sectional drawing which showed the pile thread | yarn of the rubbing cloth which concerns on this invention.

Explanation of symbols

1 rubbing roller 100, 100a rubbing cloth 110 warp yarn 120 weft yarn 130, 130a pile yarn 131 cotton fiber 132 rayon fiber

Claims (7)

A fabric structure woven with warps and wefts;
A rubbing cloth which is flocked to the base fabric structure and includes a pile yarn made of a composite fiber of cotton fiber and rayon fiber.   The rubbing cloth according to claim 1, wherein the pile yarn is manufactured by mixing and spinning the cotton fiber and the rayon fiber in a spinning stage.   The rubbing cloth according to claim 1 or 2, wherein the pile yarn is formed using a rayon fiber having a length of 20 mm or more.   The rubbing cloth according to claim 3, wherein the rayon fiber has a length of 32 mm to 54 mm.   The rubbing cloth according to claim 1, wherein a mixing ratio of the rayon fibers is 25% to 75% with respect to all pile yarns.   The rubbing cloth according to claim 1 or 2, wherein the pile yarn is woven in a V shape using a composite short fiber of cotton fiber and rayon fiber. A rubbing roller which is rotated by a driving device;
And a rubbing cloth that wraps around the rubbing roller and rubs the alignment film of the liquid crystal display device,
The rubbing apparatus comprises a rubbing apparatus comprising a ground fabric woven with warps and wefts, and a pile yarn that is flocked to the ground fabric and is made of a composite fiber of cotton fibers and rayon fibers.