JP2006095455A - Coating method and coating apparatus for coating liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform uniform coating in a web width direction and to hardly generate stripe failure even in the case of low viscosity/ultra-thin film coating. <P>SOLUTION: In the coating method, the coating liquid from a lip distal end 18A of a coating head 18 is liquid-bridged on a web 14 surface continuously traveling while wound and supported on a backup roller 12 to form a bead 20 between the web 14 and it and the web surface is coated with the coating liquid through the bead 20. At least one of a pair of bearings 28 for rotatably supporting both ends of a rotation shaft of the backup roller 12 is moved in a vertical direction (X axis direction) and/or a horizontal direction (Y axis direction). Thereby, the backup roller 12 is positioned and finely adjusted relatively to the lip distal end 18A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating solution coating method, and more particularly to a low-viscosity / ultra-thin film coating technique for producing a high-functional thin film having any of antireflection, antiglare properties and widening of the viewing angle.

  A coating apparatus such as a slot die coater or a slide die coater forms a bead between the web and the web surface that is continuously supported by being wound around a backup roller by cross-linking the coating liquid from the lip tip of the coating head. A coating solution is applied to the web surface through the bead. In such a coating apparatus, in order to apply a uniform film thickness in the web width direction, it is extremely important to set the clearance between the tip of the lip and the web supported around the backup roller uniformly in the web width direction. is there.

  As a method for uniformly adjusting the clearance, as seen in Patent Document 1, it has been proposed to finely adjust the position of the base of the coating head. Thus, when the coating head is carried from the cleaning zone and newly installed, the coating head is positioned so that the lip tip of the coating head and the backup roller are as parallel as possible. Further, in Patent Document 2, the coating head and the base are heavy objects, and there is a limit to adjusting the clearance to an extremely small clearance of about 100 μm by rapidly approaching and retracting the heavy objects with respect to the backup roller. It has been proposed that the backup roller be moved toward and away from the coating head.

By the way, the production of a high-functional thin layer film such as antireflection, antiglare and viewing angle expansion used in a liquid crystal display device or the like is produced by applying a coating liquid having these functions to the web. In recent years, an ultra-thin film (for example, a coating amount of 10 cc / s) has a low viscosity (for example, 10 mPa · s or less) compared with a conventional coating liquid in order to express a desired function with high accuracy in a highly functional thin film. m ² or less). In the case of such low-viscosity / ultra-thin film coating, it is difficult to expect the leveling effect of the coating liquid after coating, so it is important how uniform coating can be performed in the web width direction during coating. In general, in the case of a highly functional thin film, a film thickness distribution in the web width direction of 5% or less is required.
JP 2003-33710 A JP-A-63-80872

  However, a web as long as several thousand meters on which the coating liquid is applied is not necessarily flat, and has a thickness distribution on the left and right in the web width direction. Further, since the web is wound and stored in a roll shape, there is often a difference in elongation between the left and right in the web width direction, and the tension in the web width direction is often different in the state supported by the backup roller. Furthermore, the coating state may change slightly depending on the type, lot, and coating speed of the coating solution, and it is impossible to perform uniform coating in the web width direction only with Patent Document 1 and Patent Document 2, and the clearance. If this fine adjustment is not performed with high accuracy, streak failure may occur.

  As described above, when the application head is transported from the cleaning zone and newly installed, there is a problem of assembly accuracy and reproducibility due to thermal distortion, and the application head and mount are heavy and highly accurate for operations that form extremely small clearances. In order to solve problems that require special skills, as well as problems due to the thickness distribution of the web itself, positioning control with high-precision reproducibility of the horizontal and vertical methods is required, but this is achieved with the prior art. Can not do it.

  In particular, as in the above-described highly functional thin film, when the clearance between the lip tip of the coating head and the web supported by the backup roller is narrowed to 100 μm or less, and low viscosity / ultra thin film coating is performed, The film thickness distribution in the web width direction, the occurrence of streak failure, and poor coating are likely to occur, and it is difficult to eliminate these drawbacks only with the conventional technology. For example, if the clearance distribution in the web width direction is 10%, the film thickness distribution in the web width direction is 5% or more, and the requirement for a highly functional thin film cannot be satisfied.

  The present invention has been made in view of such circumstances, and since positioning control with high accuracy reproducibility of the horizontal direction and vertical method of the backup roller is possible, even in the case of low viscosity / ultra thin film coating Another object of the present invention is to provide a coating liquid coating method and apparatus that can perform uniform coating in the web width direction and are less likely to cause streak failure.

  According to a first aspect of the present invention, in order to achieve the above object, a coating liquid is cross-linked from the tip of the lip of the coating head on the surface of the web that is continuously supported while being wound around a backup roller, and the bead is interposed between the web and the web. In the coating liquid coating method for coating the web surface with the coating liquid through the beads, at least one of a pair of bearings that rotatably supports both ends of the rotating shaft of the backup roller is The backup roller is positioned and finely adjusted with respect to the tip of the lip by moving in the (X-axis direction) and / or horizontal direction (Y-axis direction).

  Uniform coating thickness in the web width direction according to various coating conditions such as the distribution of web thickness in the left and right direction in the web width direction, the difference in elongation in the left and right direction in the web width direction, and the type, lot, and coating speed of the coating liquid. To achieve this, it is not possible to cope with the so-called horizontal adjustment that moves the application heads or backup rollers close to each other as in the past, but it is necessary to make fine adjustments in the horizontal and vertical directions at both ends of the backup roller. It is.

  According to claim 1 of the present invention, at least one of the pair of bearings that rotatably supports both ends of the rotating shaft of the backup roller is arranged in the vertical direction (X-axis direction) and / or the horizontal direction (Y-axis direction). Since the backup roller is positioned and finely adjusted with respect to the tip of the lip by moving, fine adjustment in the horizontal and vertical directions is possible at both ends of the backup roller. As a result, positioning control with high accuracy reproducibility of the horizontal direction and the vertical method is possible, so the web thickness distribution in the web width direction left and right, the difference in elongation in the web width direction left and right, and the type of coating liquid, Even in various application situations such as lot and application speed, the parallelism in the web width direction between the lip tip of the application head and the web wound and supported by the backup roller can be finely adjusted with high accuracy. Accordingly, the coating thickness in the web width direction can be made uniform.

  According to a second aspect of the present invention, in the first aspect, the positioning of the backup roller is finely adjusted while applying the coating liquid to the web.

  The present invention is a method of moving a small amount of the bearing of the backup roller, and not the method of moving the entire coating head or the entire backup roller as in the prior art, so that the positioning of the backup roller can be finely adjusted while applying the coating liquid to the web. It becomes possible. As a result, the positioning of the backup roller can be fine-adjusted while monitoring the surface condition of the coating film surface applied to the web, so that the web thickness distribution in the left and right in the web width direction, the difference in elongation in the left and right in the web width direction, It is easy to cope with various application situations such as the type, lot, and application speed of the application liquid. In claim 2, the backup roller positioning fine adjustment is performed while applying the coating liquid to the web. However, the present invention allows the backup roller positioning fine adjustment even when the operation is stopped without coating. It is natural that we can do it.

A third aspect of the present invention is the method according to the first or second aspect, wherein a coating liquid having a clearance between the lip tip and the backup roller of 100 μm or less and a viscosity of 10 mPa · s or less is applied in an amount of 10 cc / m ² or less. It is characterized by.

Thus, this is because the present invention is more effective when a low viscosity / ultra thin film is applied with a clearance of 100 μm or less, a coating solution viscosity of 10 mPa · s or less, and a coating amount of 10 cc / m ² or less.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the clearance distribution in the web width direction between the lip tip of the coating head and the web supported by the backup roller is adjusted to be 10% or less. It is characterized by doing.

  This is because if the clearance distribution in the web width direction is 10%, the film thickness distribution in the web width direction is 5% or more, and the requirement for a highly functional thin film cannot be satisfied.

  According to a fifth aspect of the present invention, in order to achieve the above-mentioned object, a bead is formed between the web surface, which is wound around and supported by a backup roller, by continuously crosslinking the coating liquid from the lip end of the coating head. In the coating liquid coating apparatus for coating the web surface with the coating liquid via the beads, the pair of bearings that rotatably support both ends of the rotating shaft of the backup roller are orthogonal to the axis of the backup roller. It is characterized in that it is supported by the column via an XY table that can move in the vertical direction (X-axis direction) and the horizontal direction (Y-axis direction) on the vertical plane.

  According to the fifth aspect, the pair of bearings that rotatably support both ends of the rotating shaft of the backup roller have a vertical direction (X-axis direction) and a horizontal direction (Y (Supported in the axial direction) by stan- dards via XY tables. As a result, the backup roller can be vertically (X-axis direction) and horizontal (Y-axis direction) with respect to the lip tip of the coating head, and the web width between the lip tip and the web that is wound around and supported by the backup roller. The direction parallelism can be finely adjusted with high accuracy. Accordingly, since the clearance distribution in the web width direction formed between the lip tip and the web wound and supported by the backup roller can be made extremely small, low viscosity (for example, 10 mPa · s or less), ultrathin film (for example, Even in the case of coating with a wet film thickness of 10 μm or less, uniform coating can be performed in the web width direction, and streak failure or the like hardly occurs.

  A sixth aspect of the present invention according to the fifth aspect is characterized in that the coating head is a slot die or a slide die. The sixth aspect of the present invention is a typical coating apparatus to which the present invention is applied.

  A seventh aspect according to the fifth or sixth aspect is characterized in that the support column is supported on a movable table that can approach and retreat to the tip of the lip of the coating head.

  This is because it is more efficient to finely adjust the XY table after the backup roller is roughly positioned at the target position with respect to the coating head.

  In order to achieve the above object, an eighth aspect of the present invention is the use of the coating liquid coating method according to any one of the first to fourth aspects, wherein any one of the anti-reflection, anti-glare, and wide viewing angle thin films is used. A layer film is produced.

  This is because the coating method using the coating apparatus of the present invention is particularly effective as a coating method when producing a highly functional thin film of any one of antireflection, antiglare property, and viewing angle expansion.

  According to the coating liquid coating method and apparatus of the present invention, since the positioning control with high accuracy reproducibility of the horizontal direction and the vertical method of the backup roller is possible, even in the case of low viscosity and ultra thin film coating, Uniform coating can be performed in the web width direction, and streak failure is less likely to occur. Therefore, it is suitable as a coating method for producing a high-functional thin film having anti-reflection, anti-glare and viewing angle expansion used for a liquid crystal display device and the like.

  Preferred embodiments of a coating liquid coating method and apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a coating apparatus of the present invention, which is a slot die type coating head, and FIG. 2 shows a backup roller apparatus having an XY table. In this embodiment, an example of a slot die type coating head will be described. However, the present invention is not limited to this, and coating is performed via a bead of coating liquid formed between the coating head and the backup roller. Any applicator can be used.

  As shown in FIGS. 1 and 2, the coating apparatus 10 discharges a coating solution from a lip tip 18A of a coating head 18 in which a lip land 16 is disposed close to the surface of a web 14 that is supported by a backup roller 12 and continuously runs. Then, the bead 20 is formed by liquid crosslinking with the web 14. Then, the coating liquid is applied to the web 14 that runs continuously through the bead 20. In this case, it is preferable to provide a decompression chamber (not shown) for decompressing the web upstream side of the bead 20. Thereby, a bead can be stabilized.

  The coating head 18 is mounted on the mount 19, and a manifold 22 and a slot 24 are formed inside the coating head 18. The manifold 22 is a liquid reservoir for spreading the coating liquid supplied to the coating head 18 in the web width direction (coating width direction), and the cross section thereof may be substantially circular or semicircular. The supply of the coating liquid to the manifold 22 may be supplied from one end side of the manifold 22 or from the central portion of the manifold 22, and a plug that prevents the coating liquid from leaking to both ends of the manifold 22. Is provided.

  The slot 24 is a narrow flow path for the coating liquid from the manifold 22 to the opening 24A at the tip of the slot, and a coating width regulating plate for regulating the coating width is generally inserted at both ends of the slot 24. is there. The lip tip 18A of the coating head 18 where the opening 24A of the slot 24 is located is tapered, and a flat portion called a lip land 16 is formed at the tip.

  On the other hand, the backup roller device 11 mainly includes a pair of bearings 28 that rotatably support both ends of the rotation shaft 26 of the backup roller 12, and a pair of bearings 28, 28 perpendicular to the axis 30 of the backup roller 12. A pair of XY tables 32, 32 movable in a vertical direction (X-axis direction) and a horizontal direction (Y-axis direction) on the surface, and a pair of support columns 34 supporting the pair of XY tables 32, 32; 34 and a moving mechanism 36 that mounts the support columns 34 and moves forward and backward with respect to the coating head 18.

  In the moving mechanism 36, a pair of track rails 40, 40 are arranged in parallel on a base 38, and a moving table 44 is slidably supported on the track rail 40 via a linear bearing 42. A column 34 is erected on the table 44. A nut member 46 is fixed to the center lower surface side of the moving table 44, and a ball screw 48 is screwed to the nut member 46. Then, one end of the ball screw 48 is connected to a rotating shaft of a motor 50 that can rotate forward and backward. Thus, when the motor 50 is driven forward, the backup roller 12 moves closer to the coating head 18 side, and when the motor 50 is driven reversely, the backup roller 12 moves away from the coating head 18. The moving mechanism 36 serves to roughly adjust the clearance L (see FIG. 3) between the lip tip 18A of the coating head 18 and the web 14 wound around and supported by the backup roller 12.

  As shown in FIG. 3, the XY table 32 is provided with a pair of X-axis track rails 52, 52 parallel to the vertical direction (X-axis direction). An X-axis slider 54 is slidably supported via a bearing (not shown). Below the X-axis slider 54, an X-axis actuator 56 that is supported by the column 34 and slides the X-axis slider 54 is provided. Further, the X-axis slider 54 is provided with a pair of Y-axis track rails 58, 58 parallel to the horizontal direction (Y-axis direction), and a bearing is provided to the Y-axis track rail 58 via a linear bearing (not shown). 28 is supported. A Y-axis actuator 60 that is supported by the X-axis slider 54 and slides the bearing 28 is provided on the opposite side of the bearing 28 from the coating head. Accordingly, when the X-axis actuator 56 is driven, the bearing 28 is finely adjusted in the vertical direction, and when the Y-axis actuator 60 is driven, the bearing 28 is finely adjusted in the horizontal direction.

Accordingly, by changing the slide amount of the X-axis actuator 56 and the Y-axis actuator 60 of the pair of XY tables 32, the lip tip 18A of the coating head 18 and the web 14 supported by being wound around the backup roller 12 are supported. The parallelism in the web width direction can be finely adjusted with high accuracy. Furthermore, fine adjustment of the application point, which is the position of the lip tip 18A with respect to the backup roller 12, can be performed with high accuracy. As a result, the distribution of the clearance L in the web width direction formed between the lip tip 18A and the web 14 wound and supported by the backup roller 12 can be made extremely small, so that the low viscosity (for example, 10 mPa · s) The following) ・ Even if ultra-thin film (for example, coating amount of 10 cc / m ² or less) is applied, uniform application can be performed in the web width direction, and streak failure or the like hardly occurs.

  Prior to application, not only can the parallelism in the web width direction of the lip tip 18A and the web 14 wound and supported by the backup roller 12 be finely adjusted with high accuracy, but also during the coating operation, the web 14 It is also possible to make fine adjustments with the pair of XY tables 32 while observing the film surface state of the coating film applied to the substrate.

  In this case, in the vertical direction (X-axis direction) and the horizontal direction (Y-axis direction), it is possible to move with a stroke width of 100 μm, preferably with a stroke width of 200 μm, with an accuracy of 1 μm. Therefore, as the X-axis actuator 56 and the Y-axis actuator 60, it is preferable to use a plurality of fine movement actuators such as piezoelectric elements and electrostrictive elements provided in multiple stages.

  Next, an example of the coating method of the present invention using the coating apparatus 10 configured as described above will be described.

  For example, when the clearance L between the lip tip 18A of the coating head 18 and the web 14 wound and supported by the backup roller 12 is applied at, for example, 100 μm, the backup roller is first moved by the moving mechanism 36 so that the clearance L becomes about 100 μm. 12 is moved.

  Next, the X-axis actuator and / or the Y-axis actuator of the XY table 32 is driven, and at least one of the bearings 32 that rotatably supports the backup roller 12 is moved in the vertical direction (X-axis direction) and / or in the horizontal direction. Move in the (Y-axis direction) and make fine adjustments so that the clearance L in the web width direction is equal to 100 μm. Whether or not the clearance L is uniform at 100 μm can be confirmed using, for example, a laser measuring meter or a wedge-shaped taper gauge.

  When the fine adjustment by the XY table 32 is completed, the coating operation is started. Then, the surface quality of the coating film surface is monitored while the coating operation is continued. When the surface quality deteriorates, the XY table 32 is finely adjusted while the coating operation is continued to restore the surface quality. .

  As in the prior art, if an attempt is made to finely adjust a heavy object by moving it during the coating operation, such as the entire coating head 18 including the gantry 19 or the entire backup roller 12, the inertia force due to the movement is large, and therefore the backup roller and coating head There is a risk of damage due to collision. However, in the case of the present invention, since the bearing 28 of the backup roller 12 is moved and finely adjusted by the XY table 32, there is no risk of the backup roller 12 and the coating head 18 colliding with each other due to inertial force and being damaged. Even during the coating operation, fine adjustment with high accuracy is possible.

As a result, even in the case of low viscosity (for example, 10 mPa · s or less) and ultra-thin film (for example, coating amount of 10 cc / m ² or less), uniform coating can be performed in the web width direction, and streak failure etc. Hard to occur. Furthermore, even if there are various application conditions such as the distribution of web thickness in the left and right direction in the web width direction, the difference in elongation in the left and right direction in the web width direction, and the type, lot, and application speed of the application liquid, And the parallelism of the web width direction with the web wound and supported by the backup roller can be finely adjusted with high accuracy. Therefore, it is suitable as a coating method for producing a high-functional thin film having anti-reflection, anti-glare and viewing angle expansion used for a liquid crystal display device and the like.

  In the embodiment of the present invention, the slot die type coating head 18 has been described as an example, but a slide die type coating head may be used. The slide die type coating head is a system in which the coating liquid discharged from the slot of the coating head flows down the sliding surface and is wound around a backup roller and applied to the web supported from the sliding surface tip.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

  In the test, the application amount distribution in the web width direction is adjusted by finely adjusting the parallelism in the web width direction of the web 14 supported by being wound around the backup roller 12 with respect to the lip tip 18A of the application head 18 by an XY table. To see how it improves. As a comparative example, there is a case where application is performed without fine adjustment with an XY table.

[Example 1]
The composition of the coating solution and the coating conditions in Example 1 are as shown in Table 1.

(Test results)
In Comparative Example 1 in which the XY table 32 was not finely adjusted, the coating amount difference between the one end side and the other end side in the web width direction was 10%. In Example 1, after the operation in Comparative Example 1 is temporarily stopped, the Y-axis actuator 60 of one XY table 32 of the pair of XY tables 32 is driven to move the bearing 28 slightly in the horizontal direction by 20 μm. The application was resumed after adjusting and repositioning the horizontal position of the backup roller 12. As a result, the coating amount difference between the one end side and the other end side in the web width direction was improved to 3%.

[Example 2]
The composition of the coating solution and the coating conditions in Example 2 are as shown in Table 2.

(Test results)
In Comparative Example 2 in which the XY table was not finely adjusted, the one end side in the web width direction caused the liquid to run out, resulting in poor coating. In Example 2, while continuing the operation of Comparative Example 2, the Y-axis actuator 60 of one XY table 32 of the pair of XY tables 32 is driven to finely adjust the bearing 28 by 20 μm in the horizontal direction. Further, when the X-axis actuator 56 was further driven to finely adjust the bearing 28 in the vertical direction by 35 μm, the running out of liquid stopped, and then stable coating could be performed. As described above, the present invention can finely adjust the positioning of the backup roller with respect to the tip of the lip of the coating head while operating the coating device. Therefore, by driving the XY table while monitoring the surface quality state of the coating film surface, the optimal surface quality state can be obtained.

[Example 3]
The composition of the coating solution and the coating conditions in Example 3 are as shown in Table 3.

(Test results)
In Comparative Example 3 in which the XY table 32 was not finely adjusted, the application of the coating liquid to the web 14 was unstable, and the bead 20 was frequently cut across the entire width in the web width direction. In Example 3, while the operation of Comparative Example 3 was continued, the X-axis actuators 56 of both XY tables 32 were driven, and both bearings 28 were slid vertically downward by the same 85 μm. Application was started, and then stable application was possible.

  In the second and third embodiments, the backup roller is finely adjusted during the coating operation. However, it is natural that the backup roller can be finely adjusted even when the operation is stopped without coating.

FIG. 1 is an overall configuration diagram of a coating liquid coating apparatus according to the present invention when a slot die method is used as a coating head. Explanatory drawing explaining a backup roller device Explanatory drawing explaining an XY table

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Application | coating apparatus, 11 ... Backup roller apparatus, 12 ... Backup roller, 14 ... Web, 16 ... Lip land, 18 ... Slot die type application head, 20 ... Bead, 22 ... Manifold, 24 ... Slot, 26 ... Rotating shaft , 28 ... bearings, 30 ... axis of backup roller, 32 ... XY table, 34 ... support, 36 ... moving mechanism, 38 ... base, 40 ... track rail, 42 ... linear belling, 44 ... moving table, 46 ... Nut member, 48 ... Ball screw, 50 ... Motor, 52 ... X-axis track rail, 54 ... X-axis slider, 56 ... X-axis actuator, 58 ... Y-axis track rail, 60 ... Y-axis actuator

Claims (8)

A coating liquid is cross-linked from the tip of the lip of the coating head on the surface of the web that is continuously supported while being wound around a backup roller, and a bead is formed between the web and the coating liquid on the surface of the web via the bead. In the application method of the application liquid for applying
By moving at least one of a pair of bearings rotatably supporting both ends of the rotation shaft of the backup roller in the vertical direction (X-axis direction) and / or the horizontal direction (Y-axis direction), On the other hand, the coating liquid coating method is characterized by finely adjusting the positioning of the backup roller.   2. The coating liquid application method according to claim 1, wherein fine positioning of the backup roller is performed while applying the coating liquid to the web. 3. The coating according to claim 1, wherein a clearance between the lip tip and the backup roller is 100 μm or less and a coating liquid having a viscosity of 10 mPa · s or less is applied at a coating amount of 10 cc / m ² or less. Liquid application method.   The fine adjustment is performed so that the clearance distribution in the web width direction between the lip tip of the coating head and the web supported by the backup roller is 10% or less. Application method of coating liquid. A coating liquid is cross-linked from the tip of the lip of the coating head on the surface of the web that is continuously supported while being wound around a backup roller, and a bead is formed between the web and the coating liquid on the surface of the web via the bead. In the coating liquid coating apparatus for coating
A pair of bearings that rotatably supports both ends of the rotating shaft of the backup roller move in a vertical direction (X-axis direction) and a horizontal direction (Y-axis direction) on a vertical plane perpendicular to the axis of the backup roller. A coating liquid coating apparatus, wherein the coating liquid is supported on a support column via a possible XY table.   6. The coating liquid coating apparatus according to claim 5, wherein the coating head is a slot die or a slide die.   7. The coating liquid coating apparatus according to claim 5, wherein the support column is supported on a movable table that can approach and retreat to the tip of the lip of the coating head.   A high-functional thin layer film having any of antireflection, antiglare property, and widening of the viewing angle is produced using the coating solution coating method according to any one of claims 1 to 4. For producing a conductive thin layer film.

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