JP2007075784A - Application method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an application method by which a coating film having ruggedness can be stably formed in high yield on a supporting body. <P>SOLUTION: The application method includes supplying a coating liquid from an applicator on a backup roll onto the supporting body which is held by the backup roll having ruggedness on its surface and which continuously travels. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating method for forming a coating film having irregularities on a continuously running support.

  Various display devices such as a CRT display device, a liquid crystal display device, and a plasma display device are used as display devices for displaying still images and moving images based on electronic information.

  For example, when an image is viewed on a liquid crystal display device, an indoor lighting device or the sun may appear on the screen, and the visibility of the image is significantly impaired.

  As described above, the anti-glare film is used for the purpose of preventing the indoor lighting device and the sun from appearing on the screen, and various proposals have been made on the method of manufacturing the anti-glare film. .

  As one of them, a method of obtaining an antiglare film having a coating film having fine irregularities by pressing a plate having irregularities on a uniformly coated coating film and performing embossing is disclosed. (For example, refer to Patent Document 1).

  Also disclosed is a method of laminating a mat-shaped shaped film having fine irregularities on the surface of a uniformly coated coating film, and peeling the shaped film after curing the coating film to obtain an antiglare film. (For example, refer to Patent Document 2).

Furthermore, a method is disclosed in which an embossing roller having a reverse-shaped unevenness of a desired shape is used to supply a coating liquid to the embossing roller and transfer it to a support (for example, see Patent Document 3). .
JP 2004-29240 A Japanese Patent Laid-Open No. 6-16851 JP 2002-189106 A

  However, in the method described in Patent Document 1, while the embossing plate is in contact with the coating film and rotating, a part of the coating film may adhere to the concave portion of the embossing plate and the unevenness height may change. is there. Further, during a long time operation, the coating film adhering to the recesses peels off and becomes a foreign substance, which increases the probability of being transferred onto the film and causing a failure. Furthermore, the embossed irregularities may return over time.

  Moreover, in the method described in Patent Document 2, there is a problem that firstly, the shaped film cannot be used after peeling and a lot of waste is generated. Secondly, the coating film may be destroyed when the shaped film is peeled off due to a variation in the thickness of the coating film.

  Furthermore, in the method described in Patent Document 3, there is a concern about the influence of the remaining coating liquid after transfer when supplying the coating liquid to the embossing roller. That is, if the coating liquid remains on the embossing roller, it not only causes a failure when supplying a new coating liquid, but also may cause a spot-like failure during transfer. In addition, the concern for such failures increases with time, and long-term stability remains a question.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a coating method capable of stably forming a coating film having irregularities on a support with good yield.

The object of the present invention can be achieved by the following constitution.
(1)
A coating method comprising: supplying a coating liquid from a coating machine on a backup roller, which is continuously supported by a backup roller having an uneven surface.
(2)
The backup roller has a hollow portion, and a communication hole that communicates the hollow portion and a recess on the surface of the backup roller,
The coating method according to (1), wherein the hollow portion is connected to an exhaust device.
(3)
The backup roller is porous and has a hollow portion;
The coating method according to (1), wherein the hollow portion is connected to an exhaust device.
(4)
The coating method according to any one of (1) to (3), wherein the coating machine is an extrusion die head.

  According to the first aspect of the present invention, by supplying the coating liquid from the coating machine onto the backup roller, which is held by the backup roller having irregularities on the surface and continuously running, the unevenness can be reproduced. A stable coating film can be obtained that is excellent, has no occurrence of foreign matter that causes failure, and does not change its unevenness over time.

  According to the invention of claim 2 or 3, a negative pressure is applied between the backup roller and the support, the support is deformed faithfully to the unevenness of the backup roller, and a coating film having unevenness with excellent reproducibility is formed. I can do it.

  According to the fourth aspect of the present invention, since the coating liquid delivered from the coating machine can have a discharge pressure by using an extrusion type die head as the coating machine, air bubbles are formed in the concavo-convex portion of the support on the backup roller. Thus, the coating liquid can be reliably fed in without causing any problems.

  An example of an embodiment of the present invention will be described with reference to the drawings.

  The description in this column does not limit the technical scope of the claims or the meaning of terms. Moreover, the assertive description in the following embodiments of the present invention shows the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

  FIG. 1 is a schematic configuration diagram of a coating apparatus 100 for forming irregularities on a coating film on a support.

  In FIG. 1, reference numeral 101 denotes a support made of a plastic film or the like, which is held continuously by a backup roller 102 that rotates in the direction of the arrow in the figure, and runs continuously.

  The backup roller 102 is made of a porous material such as sintered metal, and has a hollow portion 103. The hollow portion 103 is connected to an exhaust device 104 that generates a negative pressure.

  As shown in detail in FIG. 2, fine irregularities are formed on the surface of the backup roller 102 by machining, laser processing, or the like.

  With this configuration, a negative pressure is generated between the surface of the backup roller 102 and the support 101, and the support 101 is deformed following the irregularities on the surface of the backup roller 102.

  In FIG. 1, reference numeral 105 denotes an extrusion type die head coating machine. As shown in FIG. 3, a coating liquid 107 fed from a liquid feeding pump 106 is fed from a slit 108 provided in a direction perpendicular to the paper surface of FIG. For example, an extrusion die head disclosed in Japanese Patent Application Laid-Open No. 2002-11402 can be used for discharging onto the support 101 held by the backup roller 102.

  In the case where an extrusion die head is used as the coating machine 105, application may be performed with a negative pressure in the vicinity of the upstream side of the slit 108 in the transport direction of the support 101. It is possible to perform more stable application without cutting.

  Similarly, in FIG. 1, reference numeral 109 denotes a dryer provided on the downstream side of the coating machine 105.

  The coating machine 105 is not particularly limited as long as it can supply the coating liquid 106 in a fixed amount other than the extrusion type die head of the present embodiment. For example, a slide coating machine, a curtain coating machine, A blade coater or the like can be used.

  Further, as the support 101, it is mentioned that the production is easy and the adhesiveness with the coating solution is good, and examples thereof include cellulose ester film, polyester film, polycarbonate film and the like. Can be used.

  The coating solution 107 may be either a solvent-based coating solution or a water-soluble coating solution as long as it can form irregularities and has good adhesion to the support 101. For example, polyvinyl alcohol dissolved in pure water Can be used.

  Next, operation | movement of the coating device 100 of such a structure is demonstrated.

  The support body 101 fed out from the unillustrated original winding device travels while being held by the backup roller 102.

  As shown in FIG. 4A, the coating liquid 107 ejected from the slit 108 of the coating machine 105 provided on the backup roller 102 is leveled by the ejection pressure of the coating liquid 107 so that the upper surface becomes almost the same height. It is formed. That is, the coating liquid 107 is applied in such a manner that the coating liquid 107 is large (thick) and the convex part is small (thin).

  Subsequently, the support 101 is released from the holding of the backup roller 102, and as a result, the support 101 returns to the initial flat state as shown in FIG. Enters the drier 109 while keeping the unevenness and is dried to form a coating film having unevenness.

  In this embodiment, a porous material is used as the backup roller 102. However, the present invention is not limited to this. For example, as shown in FIG. 5, irregularities are formed on the surface of metal, resin, or the like. A roller may be used, or as shown in FIG. 6, a roller in which irregularities are formed on the surface of metal, resin, or the like and a communication hole 102 </ b> A that communicates the concave portion and the hollow portion 103 may be formed.

  Alternatively, as shown in FIG. 7, the coating liquid 107 is supplied onto the first roller 110 from the applicator 105 capable of supplying a fixed amount, the thickness of the coating liquid is controlled by the blade 111, and then transferred onto the second roller 112. Alternatively, the transferred coating liquid 107 may be transferred to the support 101 on the backup roller 102 having a concavo-convex surface. Further, the backup roller 102 may be provided with a hollow portion 103 and connected to the exhaust device 104.

  Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

  As the backup roller 102, a roller having a surface unevenness of 2.5 ± 0.2 μm in height from the bottom of the recess to the apex of the protrusion and 400 ± 50 per 1 mm square is used. .

  As the support 101, a polyethylene terephthalate film having a thickness of 75 μm and a width of 300 mm was used.

  As the coating solution 107, a solution in which polyvinyl alcohol was dissolved in pure water so as to have a solid content concentration of 5% by mass and an activator was added to control wettability and viscosity was used.

  When the viscosity and wettability of the coating liquid 107 were measured, the viscosity was 10.7 mPa · s at 25 ° C. with a B-type viscometer, and the surface tension representing wettability was 34.5 dyne / cm.

  The coating speed was 50 m / min.

  Under such conditions, in any of the experiments described below, trial coating is performed first, and the fine unevenness of the coating film has a height from the lowest point of the recess to the apex of the protrusion of 1 ± 0. After confirming that the number of convex portions was 400 ± 50 per 1 mm square at 2 μm, the coating was continuously applied for 300 hours, the unevenness of the applied sample was investigated, and the number of occurrences of foreign matters was counted.

  As a comparative example, as shown in FIG. 8, a coating liquid 107 is applied to a support 101 held on a backup roller 102 having a smooth surface by a coating machine 105, and the surface is uneven while being dried by a drying machine 109. The support body 101 was passed between the embossing roller 113 having the above and the opposing roller 114, and a coating film having irregularities was formed on the support body 101.

  Table 1 shows the experimental results under the above conditions.

  Here, the experimental conditions T-1 to T-6 in Table 1 are as follows.

  T-1: The backup roller 102 shown in FIG. 5 was used.

  T-2: The backup roller 102 shown in FIG. 6 was used, and the degree of vacuum was 500 Pa.

  T-3: The backup roller 102 shown in FIG. 2 was used, and the degree of vacuum was 500 Pa.

  T-4: The backup roller 102 shown in FIG. 5 was used, and the coating method shown in FIG. 7 was used.

  T-5: The backup roller 102 shown in FIG. 6 and the coating method shown in FIG. 7 were used, and the degree of vacuum was 500 Pa.

  T-6: The backup roller 102 shown in FIG. 2 and the coating method shown in FIG. 7 were used, and the degree of vacuum was 500 Pa.

  As is clear from Table 1, the number of convex portions per 1 mm square is not changed under any of the conditions T-1 to T-6 as compared with the comparative example, but the apex of the convex portion from the lowest point of the concave portion. The height up to about 1.5 times could be formed. In addition, the number of foreign matters generated was clearly different and decreased to 1/15 to 1/50, and there was a clear difference between the two.

  As described above, by supplying the coating liquid on the backup roller from the coating machine to the support that is continuously held by the backup roller having irregularities on the surface, the irregularities have excellent reproducibility and failure A stable coating film can be formed with no occurrence of a foreign substance or the like causing a change in unevenness over time.

  Further, by applying a negative pressure to the backup roller surface using the exhaust device, the support can be faithfully deformed to the unevenness of the backup roller, and a coating film having unevenness with excellent reproducibility can be formed.

  Furthermore, by making the coating machine an extrusion type die head, it is possible to give a discharge pressure to the coating liquid delivered from the coating machine, so that air bubbles are not generated in the uneven portion of the support on the backup roller. The coating liquid can be fed.

1 is a schematic configuration diagram of a coating apparatus 100. FIG. FIG. 3 is an enlarged cross-sectional view of the surface of a backup roller 102. Sectional drawing of the principal part of an extrusion type die head. Sectional drawing of the support body 101 and the coating liquid 107 on the backup roller 102. Another embodiment (1) of the backup roller 102. Another embodiment (2) of the backup roller 102. The other Example of a coating device. Application device as a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 102 Backup roller 102A Communication hole 103 Hollow part 104 Exhaust device 105 Coating machine 106 Liquid feed pump 107 Coating liquid 108 Slit 109 Dryer 110 First roller 111 Blade 112 Second roller 113 Embossed roller 114 Opposite roller

Claims (4)

A coating method comprising: supplying a coating liquid from a coating machine on a backup roller, which is held by a backup roller having an uneven surface and continuously running. The backup roller has a hollow portion, and a communication hole that communicates the hollow portion and a recess on the surface of the backup roller,
The coating method according to claim 1, wherein the hollow portion is connected to an exhaust device. The backup roller is porous and has a hollow portion;
The coating method according to claim 1, wherein the hollow portion is connected to an exhaust device. The coating method according to claim 1, wherein the coating machine is an extrusion die head.

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