JPH06226175A - Method and device for coating base with very fine recesses - Google Patents

Abstract

PURPOSE:To fill completely very fine recesses with a coating material, improve the accuracy of the coating thickness and provide the good coating quality by filling very fine recesses with the coating material forcedly, applying the coating material to a first layer and also coating to a second layer while the coating material retains its fluidity. CONSTITUTION:A base 2 is guided by a plurality of tension stretching rolls 6, 6 and transferred from the left side to the right side. A first layer coating roll 12 for applying a coating material in very fine recesses of the base 2 is disposed on the upstream side in the transfer direction of the base 2 while a second layer coating roll 13 for applying the coating material to form a second layer of given thickness is disposed all over the first on the down stream side. Then first, the first layer coating is performed by using the first layer coating roll 12 and filling forcedly the very fine recesses with the coating material, and then the second layer of the given thickness is coated by using the second layer coating roll 13 while the coating material on the first layer retains its fluidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method and a coating apparatus for coating a surface of a base material having minute recesses with a coating agent having a predetermined thickness.

[0002]

2. Description of the Related Art Generally, a coating roll is used to apply various coating agents to a continuous base material made of resin, paper, cloth, metal such as iron and copper. The coating equipment that was used is often used.

As an example of such a coating apparatus, a coating apparatus for coating a continuous base material with a coating agent will be described below with reference to FIG.

The conventional coating apparatus 1 of this type has a coating section 3 and a drying section 4 in the running direction of a continuous base material 2 made of a long and wide resin film, paper or cloth. Are arranged and are formed so as to apply a desired coating agent. Then, the base material 2 is fed from the original fabric roll 5 on the left side of FIG.
While being stretched so as to pass through a predetermined path by 6, the sheet is conveyed rightward in the figure and finally wound up by a winding roll 7.

In the coating section 3 for coating the base material 2 with the coating agent, the coating agent is applied to the base material 2 using a coating roll 3a such as a gravure roll or a wire bar. Further, in the drying section 4 for drying the coating agent applied to the base material 2, the coating agent is dried by blowing dry air under appropriate conditions such as a predetermined temperature and air volume.

[0006]

However, in the above-mentioned conventional coating apparatus 1, when the surface of the base material 2 has a minute recess having a portion having an opening width of 0.2 mm or less, the base material 2 is When the coating agent is applied to the surface to a predetermined thickness, as shown in FIG. 7, it is not possible to completely fill the fine concave portion 8 with the coating agent, and the bottom portion of the minute concave portion 8 of the base material 2 is 9 and coating agent 1
There is a problem in that the voids 11 in which the coating agent 10 is not filled are formed between them and 0, resulting in poor coating quality.

As shown in FIG. 8, such a base material 2 has a height of about 30 μm and a size of a gap of about 0.1.
A thickness of 200 printed with a 0.2 mm barcode
A base material for a prepaid card having a size of about μm can be exemplified. When a barcode is embedded on the surface of the base material for this prepaid card and a coating agent of about 50 μm is applied, a void 11 is generated in the gap between the barcodes.

Therefore, it has been attempted to fill the coating agent 10 into the minute recesses 8 by using the coating agent 10 as a solvent having a large amount of solvent and having a low viscosity that easily enters a narrow gap. The larger the amount, the more difficult it becomes to adjust the coating thickness. In addition, it is now difficult to use a large amount of solvent in order to prevent environmental damage caused by the solvent. Further, if the coating agent 10 is forcibly dried with dry air or the like in the state where the voids 11 are present, the voids 11 expand due to heat and foam, so that good coating quality cannot be secured. There was also.

In order to prevent environmental damage, a solvent-free UV-curable coating agent (hereinafter referred to as UV coating agent), electron beam-curable coating agent (hereinafter referred to as EB coating agent) However, hot-melt coating agents, 2-liquid reactive coating agents, etc. are used, but these coating agents have high viscosity. There is a disadvantage that it cannot be completely filled.

The present invention has been made in view of these points, and overcomes the above-mentioned problems with the conventional ones.
When a coating roll with a predetermined thickness is applied to the surface of a base material having minute recesses, all types of coating agents can be completely coated in the minute recesses with a simple configuration. It is an object of the present invention to provide a coating method and a coating device for a base material having minute recesses that can increase the accuracy of the coating thickness while filling the agent and can obtain good coating quality. To do.

[0011]

In order to achieve the above-mentioned object, the method of the present invention according to claim 1 uses a coating roll on the surface of a base material having minute recesses to form a coating agent having a predetermined thickness. In the coating method for coating, the first minute layer is coated by first forcibly filling the minute recesses with a coating agent, and then the above-mentioned 1
It is characterized in that the second layer is applied while the fluidity of the second layer coating agent is maintained.

The forced coating of the first layer has a diameter of 50.
It is characterized in that it is applied by kiss coating using a coating roll having a size of not more than mm or by nip coating in which a base material is sandwiched by a coating roll and a backup roll.

Further, the apparatus of the present invention according to claim 4 is a coating apparatus for applying a coating agent having a predetermined thickness onto a surface of a substrate having minute recesses by using a coating roll. The coating roll for one layer for forcibly filling the inside with the coating agent to apply the first layer, and the second layer while the fluidity of the first layer coating agent is maintained. It has a two-layer coating roll for coating.

The one-layer coating roll is characterized in that it is composed of a coating roll having a diameter of 50 mm or less for kiss coating, or is formed in a pair with a backup roll for nipping the substrate while nipping it. It is characterized by

[0015]

By applying the coating on the surface of the base material having the minute recesses on the surface by using the coating apparatus of the present invention according to the coating method of the present invention, the coating agent is completely filled in the minute recesses. It is possible to apply the coating with high accuracy of the coating thickness while filling.

That is, first, a coating roll for one layer is used to forcibly fill the minute recesses with the coating agent to apply the first layer, and then the coating agent for the first layer is applied. While maintaining the fluidized bed, a second-layer coating roll is used to coat a second layer having a predetermined thickness.

The forced coating of the first layer has a diameter of 50.
The coating is performed by kiss coating using a coating roll having a size of not more than mm, or by nip coating in which the base material is sandwiched between the coating roll and the backup roll.

With this, the surface of the base material having the minute recesses can be coated with a coating agent having a predetermined thickness, and the minute recesses can be completely filled without generating voids.
An extremely high quality coating can be applied. As a result, all kinds of coating agents can be completely filled in the minute recesses and good coating can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

1 to 4 show an embodiment of the present invention.

FIG. 1 shows the whole of this embodiment. The substrate 2 is guided by a plurality of spreading rolls 6 and is transferred from the left side to the right side in the drawing. A one-layer coating roll 12 for coating the coating agent 10 as the first layer in the minute concave portion 8 of the base material 2 is arranged on the upstream side in the transfer direction of the base material 2, and on the downstream side thereof. A two-layer coating roll 13 for applying the coating agent 10 as a second layer having a predetermined thickness is provided on the first layer.

To explain further, one of the one-layer coating rolls 12 is formed to have a relatively small diameter of about 20 to 50 mm, and the lower surface of the base material 1 is coated with the first layer by kiss coating. Is being done. The other two-layer coating roll 13 is also formed to have a relatively small diameter of about 20 to 50 mm, and the lower surface of the base material 1 is similarly kiss-coated to apply the second layer.

2 and 3 show the details of the coating roll 12 for one layer. In this embodiment, a gravure roll (hereinafter referred to as reference numeral 12) is used as the one-layer coating roll 12. The gravure roll 12 is laid horizontally with its axial direction orthogonal to the traveling direction of the base material 2. Further, the gravure roll 12 is mounted on a pair of support members 15 and 15 which are erected on a base 14 which is vertically moved by a known appropriate lifting drive mechanism (not shown).
It is rotatably supported by 6 and 16. Rotational force is transmitted from the drive motor to the gravure roll 12 via a coupling (both not shown). In this embodiment, the gravure roll 12 is rotated in the opposite direction (counterclockwise in FIG. 1) at the contact portion with the running direction of the base material 2.
Further, an engraved portion 17 having a width narrower than the entire width of the base material 2 is engraved on the outer peripheral surface of the gravure roll 12 over the entire circumference. The pattern of the engraved portion 17 is formed in a diagonal groove pattern, a pattern in which pyramid-shaped concave portions or truncated pyramid-shaped concave portions are arranged in a lattice pattern, or the like. This gravure roll 1
An overflow receiver 18 is fixed to the base 14 below 2 by tightening bolts 19. Then, a coating agent supply nozzle 20 for supplying the coating agent to the gravure roll 12 is fixed on the overflow receiver 18. This coating agent supply nozzle 20 is formed to have the same width as the engraving portion 17 of the gravure roll 12, as shown in FIG. Further, as shown in FIG. 2, the coating agent supply nozzle 20
Is formed integrally with two split nozzle pieces 20a, 20b, which are tightly fixed to each other with a thin intervening material 21 interposed in the lower half. A coating agent storage portion 22 having a circular cross section, which is long in the width direction, is formed in the upper portion of the thin-walled sandwich 21 to temporarily store the coating agent fed from the outside. Then, on the upper part of the coating agent storage section 22, the thin-walled sandwiched material 21
The elongated communication groove 23 is formed by not interposing. Then, at the upper end portion of the coating agent supply nozzle 20, the coating agent fed from the coating agent storage section 22 through the communication groove 23 is stored and applied upward to the engraving section 17 of the gravure roll 12. An elongated nozzle portion 24 is formed. The length of the nozzle portion 24 is formed to be the same as the width of the engraving portion 17 of the gravure roll 12, and the width regulation for closing the both end portions of the coating material supply nozzle 20 in the width direction is performed. Closing member 28, 28
Is stuck. Further, immediately before the engraving section 17 of the gravure roll 12 applies the coating agent stored in the nozzle section 23 to the lower surface of the base material 11, a doctor for wiping off the excess coating agent applied to the engraving section 17 A blade 25 is provided. This doctor blade 25 is a gravure roll 12
It is attached to a holder 27 that is rotatably supported on a pivot 26 that is parallel to. And this doctor blade 25
Fills the engraved portion 17 of the gravure roll 12 with an appropriate amount of the coating agent over the entire width, and also functions to scrape off the coating agent on the outer portion from both ends of the engraved portion 17.

The other two-layer coating roll 13 is also the same as the one-layer coating roll 12 in the gravure roll (hereinafter referred to as reference numeral 13).
Is used, and other configurations are formed in the same manner as in the case of the one-layer coating roll 12, and the description thereof will be omitted.

Next, description will be given of a case where the coating apparatus of this embodiment is used to coat the surface of a base material having minute recesses.

For example, the base material 2 for a prepaid card shown in FIG. 8 is conveyed at a predetermined speed in FIG. 1, and first the coating roll 12 for the first layer applies the first layer.

For example, as an example, the base material 2 is conveyed at a speed of 2 m / min. Gravure roll 12 with a diameter of about 3
The engraved portion 17 of 0 mm and the outer peripheral surface is formed as a diagonal groove pattern of 110 mesh / inch, and is rotated in a direction opposite to the conveying direction of the base material 2 at a relatively high speed of 300 rpm. Then, the coating agent 10 supplied to the nozzle portion 24 of the coating agent supply nozzle 20 is wound up by the gravure roll 12, and the doctor blade 25 scrapes off the excess coating agent 10 from the outer peripheral surface of the gravure roll 12, The coating agent 10 accurately measured by the engraving section 17 is guided to the coating section on the lower surface of the base material 2 and provided for coating. In this embodiment, as shown in FIG. 4, since the gravure roll 12 is formed to have a relatively small diameter, the circumferential direction of the contact portion with the base material 2 in the coating portion (the circular arc portion with the winding angle α). The length is shortened, and the frictional force between the base material 2 and the gravure roll 12 is suppressed to be small. As a result, a film of the coating material 10 is formed between the lower surface of the base material 2 and the outer peripheral surface of the gravure roll 12 from a slightly upstream portion to a downstream portion of the contact portion in the transport direction of the base material 2. The radial component force of the gravure roll 12 of the tension of the base material 2 acts on the film portion of the coating agent 10, and the radial component force acts in the direction perpendicular to the surface of the base material 2. As a result, the coating material 10 is reliably filled in the gap between the barcodes due to the component force. Further, in the wedge-shaped coating agent film portion formed between the base material 2 and the gravure roll 12 on the downstream side of the coating portion in the transport direction of the base material 2, the coating agent 10 has a small diameter. Due to the pressing force having a component force in a direction closer to the normal direction of the lower surface of the base material 2 due to the rotation, the coating material 10 is more surely filled in the gap between the barcodes.

The base material 2 thus coated with the first layer
While the fluidity of the coating agent 10 of the first layer is maintained, the second coating layer 13 of FIG.
The coating agent 10 of the layer is applied, and the coating agent 10 is applied to a predetermined thickness by combining both layers. That is, the gravure roll 13 has a diameter of about 30 mm and an engraved portion 17 on the outer peripheral surface of 90.
Formed as a mesh / inch diagonal groove pattern, 20
The coating material 10 is rotated at a relatively low speed of ˜30 rpm in the direction opposite to the conveying direction of the base material 2 and is supplied to the nozzle portion 24 of the coating material supply nozzle 20 in the same manner as the first layer.
Is wound up by the gravure roll 13, the surplus coating material 10 is scraped off from the outer peripheral surface of the gravure roll 13 by the doctor blade 25, and the coating material 10 accurately measured by the engraving part 17 is applied to the lower surface of the base material 2. Lead to the coating department and let it coat.

According to the coating method of this embodiment, since the second layer is coated where the first layer coating agent has fluidity, the first layer coating agent is later applied. A coating layer having uniform properties as a whole is formed by being integrated with the coated second layer coating agent.

As a result, the surface of the base material 2 having the minute recesses can be coated with a coating agent having a predetermined thickness, and the minute recesses can be completely filled without generating voids.
An extremely high quality coating can be applied. As a result, all kinds of coating agents can be completely filled in the minute recesses and good coating can be performed. That is, a solvent-free UV coating agent, EB, which could not be coated in the past.
A coating agent having a high viscosity such as a coating agent, a hot melt coating agent, a two-liquid reactive coating agent, etc. can be favorably coated, and environmental destruction can be prevented.

FIG. 5 shows another embodiment of the present invention.

In this embodiment, the base material 2 is sandwiched between the coating roll 30 for the first layer and the backup roll 31 for the first layer, and the coating agent storage container is held by the coating roll 30 for the first layer. The coating agent 10 stored in 32 is guided to the coating section,
The coating material 10 is forcibly filled into the minute recesses of the base material 2 by the clamping force. The one-layer coating roll 30 is formed to have a relatively large diameter of 100 mm or more, and is horizontally stretched so that the axial direction thereof is orthogonal to the traveling direction of the base material 2. The one-layer coating roll 30 is used for the coating agent 10 stored in the coating agent storage container 32.
The lower part of the coating material 10 is soaked in the base material and is rotated so that an excess portion of the coating material 10 can be scraped off by the doctor blade 33. In addition, it is preferable that the one-layer coating roll 30, the coating agent storage container 32, and the doctor blade 33 are unitized and formed so as to be vertically movable. Further, the diameter of the one-layer coating roll 30 may be formed to be relatively small as in the above-mentioned embodiment. Others are formed in the same manner as in the above embodiment.

Also in this embodiment, as in the case of the above-mentioned embodiment, the surface of the base material 2 having minute recesses can be coated with a coating agent having a predetermined thickness, and voids are not generated in the minute recesses. It can be filled completely and a very high quality coating can be applied.

The present invention is not limited to the above embodiment, but can be modified as necessary. For example, various rolls such as a gravure roll and a wire bar can be applied as the coating rolls 12, 13 and 30. In addition, the two-layer coating roll of each of the above-described examples is shown in FIG.
It may be formed to have a large diameter like the single-layer coating roll 30 and the backup roll 31 may be provided to perform the coating by nip coating, or the backup roll 31 may not be provided to perform the kiss coating. Good.

[0035]

As described above, since the coating method and the coating apparatus for the base material having the minute recesses of the present invention are constituted and operate, a coating roll is used on the surface of the base material having the minute recesses. When applying a coating agent of a predetermined thickness, all kinds of coating agents are completely filled in the minute recesses with a simple configuration, and the accuracy of the coating thickness is increased. It is possible to obtain good coating quality and the like.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a coating apparatus of the present invention.

FIG. 2 is a cross-sectional view showing details of a one-layer coating roll.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an explanatory diagram showing a coating state on a base material.

FIG. 5 is a configuration diagram showing another embodiment of the coating apparatus of the present invention.

FIG. 6 is a configuration diagram showing a conventional coating device.

FIG. 7 is a cross-sectional view showing a conventional coating tool for minute recesses.

FIG. 8 is a perspective view showing an example of a base material having minute recesses.

[Explanation of symbols]

 2 Base material 12, 32 1 layer coating roll 13 2 layer coating roll 33 Backup roll

Claims (6)

[Claims] 1. A coating method for applying a coating agent having a predetermined thickness onto a surface of a base material having microscopic depressions by first forcibly applying the coating agent into the microscopic depressions. A base material having minute recesses, characterized in that it is filled to apply a first layer, and then a second layer is applied while the fluidity of the first layer coating agent is maintained. Coating method. 2. The coating for the base material having minute recesses according to claim 1, wherein the coating of the first layer is performed by kiss coating using a coating roll having a diameter of 50 mm or less. Method. 3. The base material having minute recesses according to claim 1, wherein the first layer is applied by nip coating in which the base material is sandwiched by a coating roll and a backup roll. Coating method. 4. A coating apparatus for applying a coating agent having a predetermined thickness onto a surface of a base material having microscopic depressions by forcibly filling the microscopic depressions with the coating agent. A first-layer coating roll for applying the first-layer coating and a second-layer coating roll for coating the second-layer while the first-layer coating agent maintains fluidity. A coating method for a base material having minute recesses, which comprises: 5. The coating apparatus for a substrate having minute recesses according to claim 4, wherein the one-layer coating roll is a coating roll having a diameter of 50 mm or less on which kiss coating is performed. 6. The base material having minute recesses according to claim 4, wherein the one-layer coating roll is formed in a pair with a backup roll that holds the base material and performs nip coating. Coating equipment.