Coating device

Abstract

To provide a coating applicator which can form a coating film having excellent smoothness.SOLUTION: A coating applicator of the invention applies a paint to a base material P and includes a spreader roll 1, a doctor roll 2, and a receiving member 3. In the coating applicator of the invention, the receiving member 3, the spreader roll 1, and the doctor roll 2 form a liquid reservoir part 4 so that the paint adheres to the spreader roll 1 and the doctor roll 2. The receiving member 3 can be provided at the outer side relative to the spreader roll 1 and the doctor roll 2. The spreader roll 1 can be configured to rotate in an opposite direction of a rotation direction of the doctor roll 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coating device used for coating a base material with a paint.

Background Art

[0002] On the surface of a substrate, film, sheet, plate, panel, etc. (hereinafter collectively referred to as "base material"), a resist paint, conductive paint, insulating paint, protective paint, strengthening paint, UV light-shielding paint, antistatic paint, coloring paint, functional coating agent, etc. (hereinafter collectively referred to as "paint") may be applied. As an example, there are cases such as applying a resist to a printed wiring board or applying an adhesive to a copper foil.

[0003] Conventionally, as an apparatus for applying a paint to a base material, there is known an apparatus including a coating roll for applying the paint to the base material, a doctor roll for supplying the paint to the coating roll, and a paint container for storing the paint (Patent Document 1). In this apparatus, the paint in the paint container is picked up by the doctor roll, the paint is transferred from the doctor roll to the coating roll, and the paint is transferred from the coating roll to the base material, whereby the paint is applied to the base material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above coating apparatus, since only the doctor roll is in direct contact with the paint, the uniformity of the film thickness of the paint applied to the base material depends on the amount of paint adhering to the doctor roll, the smoothness of the paint on the surface of the doctor roll, the amount of paint transferred from the doctor roll to the coating roll, and the smoothness of the transferred paint.

[0006] Therefore, for example, when the paint on the surface of the doctor roll lacks smoothness, the paint transferred to the surface of the coating roll becomes non-uniform, and as a result, the film thickness of the paint transferred to the substrate becomes non-uniform.

[0007] Since the smoothness of the coating film applied to the substrate affects the mounting density of electronic components, it is said that it is desirable for the coating film to be as smooth as possible. In recent years, with the advent of the 5G era and the progress of high-density substrates, this demand has been increasing more than ever.

[0008] The present invention has been made in view of the above circumstances, and the problem to be solved is to provide a coating device capable of forming a coating film having excellent smoothness as compared with conventional coating devices.

Means for Solving the Problems

[0009] The coating device of the present invention is a coating device for applying paint to a substrate, and includes a coating roll, a doctor roll, and a receiving member. In the coating device of the present invention, a liquid pool portion is formed by the receiving member, the coating roll, and the doctor roll so that the paint adheres to the coating roll and the doctor roll.

Effects of the Invention

[0010] Since the coating device of the present invention has a liquid pool portion formed so that the paint adheres to the coating roll and the doctor roll, the amount of paint adhering to the coating roll is stable, and a smooth coating film can be formed on the substrate.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0012] (Embodiment 1) An example of an embodiment of the coating apparatus of the present invention will be described with reference to the drawings. As an example, the coating apparatus shown in FIG. 1 is an apparatus for applying a coating material to a substrate P, and includes a coating roll 1, a doctor roll 2, and a receiving member 3. In this embodiment, a liquid pool portion 4 is formed by the receiving member 3, the coating roll 1, and the doctor roll 2 so that the coating material adheres to the coating roll 1 and the doctor roll 2. On both outer sides in the longitudinal direction of the coating roll 1 and the doctor roll 2, a spill prevention 5 is provided to prevent the coating material accumulated in the liquid pool portion 4 from spilling. As shown in FIG. 2, the coating roll 1, the doctor roll 2, and the receiving member 3 are provided at the same height on both sides sandwiching the substrate P.

[0013] The coating roll 1 is a member for transferring a coating material to the substrate P to form a coating film. For the coating roll 1, in addition to a rubber roll and a metal roll, a roll having a DLC film on its outer periphery can be used. The rubber roll includes natural rubber and synthetic rubber. The metal roll includes those plated with carbon steel.

[0014] In this embodiment, a solid roll without unevenness (cells) on its outer peripheral surface is used as the coating roll 1. However, as the coating roll 1, in addition to the solid roll, a engraved roll provided with cells of various shapes such as spiral grooves, single grooves, and dots on its outer peripheral surface can also be used. The shape of the cells is an example and other shapes may also be used.

[0015] The coating roll 1 of this embodiment is configured to rotate constantly regardless of whether it is in contact with the base material P or not. The coating roll 1 rotates in the direction opposite to the moving direction of the base material P. Specifically, as shown in FIG. 2, one coating roll 1 (on the left side in the figure) rotates clockwise, and the other coating roll 1 (on the right side in the figure) rotates counterclockwise. The coating roll 1 may be configured to rotate in the opposite direction (the positive direction with respect to the moving direction of the base material P). In any case, it is configured to rotate in the direction opposite to the rotation direction of the contacting doctor roll 2.

[0016] The doctor roll 2 is a member for supplying paint to the coating roll 1 and smoothing (levelling) the paint on the surface of the coating roll 1. As the doctor roll 2, in addition to a metal roll or a rubber roll, a roll provided with a DLC film on the outer periphery of these can be used. The rubber roll includes natural rubber and synthetic rubber. The metal roll includes those plated with carbon steel.

[0017] In this embodiment, a metal roll provided with a DLC film on the outer periphery of carbon steel is used as the doctor roll 2. Although not shown, various shapes of unevenness (cells) such as spiral grooves, single grooves, and dots are provided on the outer peripheral surface of the doctor roll 2. The shape of the cells is an example and other shapes may also be used. A solid roll without cells can also be used as the doctor roll 2.

[0018] In this embodiment, the coating roll 1 and the doctor roll 2 have the same diameter and length. The coating roll 1 and the doctor roll 2 can also have different diameters and lengths. However, it is preferable to use a doctor roll 2 with a larger diameter than the coating roll 1. By using a doctor roll 2 with a larger diameter than the coating roll 1, the portion of the doctor roll 2 with the paint adhered thereto is always in contact with the coating roll 1 while the coating roll 1 makes one revolution. Therefore, the paint on the outer peripheral surface of the coating roll 1 is likely to be made uniform.

[0019] The receiving member 3 is a member that forms a liquid reservoir portion 4 between the coating roll 1 and the doctor roll 2. The receiving member 3 of this embodiment is a flat plate member that is longer than the coating roll 1 and the doctor roll 2. The receiving member 3 can be formed of metal, resin, rubber, or the like.

[0020] As shown in FIG. 2, the receiving member 3 of this embodiment has a size that straddles both the coating roll 1 and the doctor roll 2. The receiving member 3 is provided obliquely with respect to a virtual axis (indicated by a two-dot chain line in FIG. 2) parallel to the straight line in the moving direction of the base material P that moves vertically, such that the angle α formed between the virtual axis and the lower end side of the receiving member 3 is about 40 degrees. This angle can be adjusted as appropriate.

[0021] In this embodiment, the coating roll 1 and the doctor roll 2 are in contact with each other, and the coating roll 1 and the receiving member 3 are in contact with each other, thereby forming a liquid reservoir portion 4 in which the paint accumulates. Specifically, a liquid reservoir portion 4 is formed between the receiving member 3, the coating roll 1, and the doctor roll 2, and the paint accumulated in the liquid reservoir portion 4 adheres to both the coating roll 1 and the doctor roll 2.

[0022] When the paint accumulated in the liquid reservoir portion 4 adheres directly to the coating roll 1 as in this embodiment, the coating roll 1 can pick up the paint by itself. Therefore, even if the amount of paint transferred from the doctor roll 2 is small, uneven application of the paint to the base material P is less likely to occur, and a smooth coating film can be formed on the surface of the base material P.

[0023] In this embodiment, the doctor roll 2 is disposed outside and at a higher position than the coating roll 1. With such a positional relationship, there is an advantage that the paint adhering to the coating roll 1 does not fall due to gravity, and the paint can be reliably transferred to the base material P. Further, since the distance from the contact point with the doctor roll 2 to the base material P is shortened, there is an advantage that even when applying a paint that is likely to volatilize, it can be transferred to the base material P before volatilizing.

[0024] The coating apparatus of this embodiment includes, in addition to the coating roll 1, the doctor roll 2, and the receiving member 3, a holder 6, a lower receiver 7, a pressing pin 8, and an attitude holder 9. Note that the holder 6, the lower receiver 7, the pressing pin 8, and the attitude holder 9 may be provided as necessary, and any of them can be omitted or replaced with other means.

[0025] The holder 6 is a member that holds the base material P and moves it in the vertical direction. The holder 6 of this embodiment is a clip-shaped member that sandwiches the upper part of the base material P. The holder 6 is configured to move up and down by a lifting device (not shown). As shown in FIGS. 1 and 3(a), in this embodiment, an example is given where there are three holders 6, but the number of holders 6 may be more or less than three.

[0026] When holding a flexible base material such as a flexible printed circuit board, in order to suppress the wobbling of the base material P, a holder 6 that sandwiches both end sides in the width direction of the base material P as shown in FIG. 3(b) can also be used. This holder 6 has a length that can sandwich the entire length or substantially the entire length in the length direction of the base material P. Other than these, other holders can also be used for the holder 6.

[0027] The lower receiver 7 is a member that supports the base material P that has descended to a predetermined position from below. In this embodiment, an upward U-shaped gutter-shaped member that is longer in the width direction of the base material P is used as the lower receiver 7. The lower receiver 7 is disposed at a position lower than the coating roll 1, the posture holder 9, and the pressing pin 8. The lower receiver 7 is provided at a position such that when the base material P reaches the lower receiver 7, the vicinity of the upper end of the base material P is at approximately the same height as the coating roll 1.

[0028] The pressing pin 8 is a pin-shaped member that temporarily presses both surfaces of the base material P that has descended to a predetermined position. The pressing pin 8 of this embodiment is configured to move in a direction approaching the base material P and a direction away from the base material P by a driving means (not shown). In this embodiment, an example is given where two are provided on the outside of each surface of the base material P (a total of four), but the number of pressing pins 8 may be more or less than four.

[0029] The posture holder 9 is a member for holding the standing posture of the base material P in contact with or in proximity to both surfaces of the base material P. The posture holder 9 of this embodiment is a rectangular parallelepiped block made of rubber. In this embodiment, two posture holders 9 are provided on the outside of one surface of the base material P and two on the outside of the other surface (a total of four). As shown in FIGS. 3(a) and 3(b), the posture holders 9 on the outside of each surface are provided at intervals in the width direction of the base material P. The number of posture holders 9 can be more or less than four.

[0030] Each posture holder 9 of this embodiment is configured to move in a direction approaching the base material P and a direction away from the base material P by a driving means (not shown). Each posture holder 9 can be configured to move individually, but in this embodiment, the two posture holders 9 that press the same surface of the base material P are configured to move synchronously.

[0031] In this embodiment, the posture holder 9 is configured to move separately from the coating roll 1, the doctor roll 2, and the receiving member 3. However, the posture holder 9 may be configured to move in synchronization with the coating roll 1, the doctor roll 2, and the receiving member 3. Each posture holder 9 can also be fixed at a fixed position without moving.

[0032] Each posture holder 9 is provided below the coating roll 1. The posture holder 9 can be provided in contact with the coating roll 1 or separated from it. When provided in contact with the coating roll 1, the upper surface of the posture holder 9 can be recessed in an arc shape along the outer circumference of the coating roll 1.

[0033] In this embodiment, the posture holder 9 is made of rubber, but the posture holder 9 may be made of a material other than rubber. In any case, when applying the paint with the coating roll 1, it is preferable that the material has a low frictional resistance such that it does not impede the smooth movement (lifting and lowering) of the base material P. The posture holder 9 can also have a shape with a small contact area so as not to impede the smooth upward movement of the base material P. Further, at least the contact surface of the posture holder 9 may be processed with a fluororesin to reduce the frictional resistance.

[0034] In this embodiment, an example is given where the paint is applied while raising the base material P. However, as shown by the dashed-dotted line in FIG. 2, a configuration may be adopted in which the paint is applied while lowering the base material P. Also in this case, the coating roll 1 may rotate in the reverse direction with respect to the moving direction of the base material P or in the forward direction with respect to the moving direction of the base material P.

[0035] (Embodiment 2) Another example of an embodiment of the coating apparatus of the present invention will be described with reference to the drawings. The basic configuration of the coating apparatus of this embodiment is the same as that of Embodiment 1. The difference lies in the moving method of the base material P. In the above embodiment, an example is given where the base material P is held by the holder 6 and moved in the vertical direction (when the base material P is a single sheet). However, the coating apparatus of the present invention can also apply paint to a base material P that moves in a roll-to-roll manner as shown in FIG. 4.

[0036] Specifically, as shown in FIG. 4, the pay-off roll 10 and the take-up roll 11 are arranged at intervals in the vertical direction, and the base material P can be fed from the pay-off roll 10 and taken up by the take-up roll 11.

[0037] In the example shown in FIG. 4, the case where the pay-off roll 10 is provided on the lower side and the take-up roll 11 is provided on the upper side is shown as an example. However, the pay-off roll 10 and the take-up roll 11 can be reversed up and down, and the paint can be applied while moving the base material P downward as shown by the dashed-dotted line in FIG. 4.

[0038] In the case of the configuration as shown in FIG. 4, the same ones as those in the first embodiment can be used for the coating roll 1, the doctor roll 2, and the receiving member 3. When the base material P is moved in a roll-to-roll manner, the holder 6, the lower receiver 7, the pressing pin 8, and the posture holder 9 can be omitted.

[0039] (Other Embodiments) In both of the above embodiments, the case where the diameters of the coating roll 1 and the doctor roll 2 are the same is taken as an example. However, the coating roll 1 and the doctor roll 2 can have different diameters. Also, in the above embodiments, the case where the lengths of the coating roll 1 and the doctor roll 2 are the same is taken as an example. However, the coating roll 1 and the doctor roll 2 can also have different lengths.

[0040] In both of the above embodiments, the case where a solid roll is used as the coating roll 1 and a engraved roll is used as the doctor roll 2 is taken as an example. However, an engraved roll can be used as the coating roll 1 and a solid roll can be used as the doctor roll 2. Also, if possible, both the coating roll 1 and the doctor roll 2 can be solid rolls or engraved rolls.

[0041] In both of the above-described embodiments, an example is given in which a rubber roll is used as the coating roll 1 and a metal roll (a carbon steel roll with a DLC film formed thereon) is used as the doctor roll 2. However, it is also possible to use the above-described metal roll as the coating roll 1 and a rubber roll as the doctor roll 2. Further, if possible, both the coating roll 1 and the doctor roll 2 may be metal rolls or rubber rolls.

[0042] As the metal roll, for example, stainless steels in general, such as austenitic and martensitic types represented by SUS304 and SUS440C, carbon steels such as STKM13A and S25C with HC plating or Ni plating on the surface, and those with a DLC film applied on the surface of stainless steel, carbon steel, or HCr plating can be used.

[0043] In both of the above-described embodiments, an example is given in which the doctor roll 2 is disposed at a position higher than the coating roll 1. However, as shown in FIG. 5, the doctor roll 2 can also be disposed at a position lower (a lower position) than the coating roll 1. In this case, in the figure, the doctor roll 2 located on the left side of the substrate P rotates clockwise, and the coating roll 1 rotates counterclockwise. On the other hand, in the figure, the doctor roll 2 located on the right side of the substrate P rotates counterclockwise, and the coating roll 1 rotates clockwise. This configuration is a configuration that is likely to be adopted when the viscosity of the paint is high enough not to drop due to gravity.

[0044] Although not described in the above-described embodiments, the doctor roll 2 can be configured to be movable in the direction of pushing the coating roll 1 and in the direction opposite thereto (the direction of releasing the pushing). Similarly, the coating roll 1 can be configured to be movable in the direction of pushing the substrate P and in the direction opposite thereto (the direction of releasing the pushing).

[0045] In both of the above-described embodiments, an example is given in which the coating roll 1, the doctor roll 2, and the receiving member 3 are provided at the same height on both sides sandwiching the base material P. However, as shown in FIG. 6, the coating roll 1, the doctor roll 2, and the receiving member 3 can also be provided at different heights on both sides sandwiching the base material P. This configuration is an easily adoptable configuration when the base material P is a soft material such as a film or a copper foil.

[0046] In both of the above-described embodiments, an example is given in which the spill stoppers 5 are provided on both outer sides in the longitudinal direction of the coating roll 1 and the doctor roll 2. However, by adding a configuration corresponding to the spill stoppers 5 to the receiving member 3, the spill stoppers 5 can also be omitted.

[0047] The present invention is not limited to the structures and shapes of the above-described embodiments, and various modifications and changes are possible without departing from the gist thereof.

[0048] Next, the operation of the coating apparatus of the present invention will be described with reference to the drawings. Here, as an example of the operation of the coating apparatus of the present invention, the operation of the coating apparatus of Embodiment 1 and the operation of the coating apparatus of Embodiment 2 will be described.

[0049] The coating apparatus of Embodiment 1 operates as follows. In FIGS. 7(a) to (d) and FIGS. 8(a) to (d), for the holder 6, the pressing pin 8, and the posture holder 9, a state of being in contact with or close to the base material P is shown by a solid line, and a state of not being in contact with or not close to the base material P is shown by a two-dot chain line. (1) The base material P held by the holder 6 is set at a predetermined position (FIGS. 7(a), 8(a)). (2) The base material P held by the holder 6 descends to a predetermined position and is supported by the lower receiver 7 (FIGS. 7(b), 8(b)). (3) The pressing pins 8 abut on both surfaces of the base material P, and the base material P is held (FIGS. 7(c), 8(c)). At this time, just before the base material P is held by the pressing pins 8, the clamping of the base material P by the holder 6 is released. Also, the posture holder 9 approaches or contacts both surfaces of the base material P, and the standing posture of the base material P is maintained. (4) The coating rolls 1 on both sides of the base material P come into contact with the base material P, and the paint held on the surface of the coating roll 1 is transferred to the base material P (Figs. 7(d) and 8(d)). At this time, the upper end of the base material P is clamped again by the holder 6 and the base material P is pulled up, and the paint on the surface of the coating roll 1 is transferred to the pulled-up base material P. Note that the holding of the base material P by the pressing pin 8 is released immediately before the coating roll 1 contacts the base material P.

[0050] The coating apparatus of Embodiment 2 operates as follows. (1) The base material P held by the pay-out roll 10 and the take-up roll 11 is set at a predetermined position (Figs. 9(a) and 10(a)). (2) By the operation of the pay-out roll 10 and the take-up roll 11, the coating rolls 1 come into contact with both sides of the base material P moving from the pay-out roll 10 side to the take-up roll 11 side, and the paint held on the surface of the coating roll 1 is transferred to the base material P (Figs. 9(b) and 10(b)).

[0051] In both of the above operations, the paint applied from the coating roll 1 to the base material P is the paint supplied from the doctor roll 2 and the paint picked up by the coating roll 1 itself, and is leveled to a predetermined thickness when passing through both rolls.

[0052] As described above, in the coating apparatus of each of the above embodiments, since the paint is not only supplied from the doctor roll 2 to the coating roll 1 but also the coating roll 1 is configured to be able to pick up the paint by itself, the amount of paint adhering to the coating roll 1 is likely to be stable, and a smooth coating film can be formed on the base material P.

[0053] The coating apparatus of the present invention can be used for applying paint to various base materials P, and is particularly suitable for applying a resist to a printed wiring board such as a rigid board or a flexible board, or applying an adhesive to a copper foil.

Explanation of Reference Numerals

[0054] 1 Coating roll 2 Doctor roll 3 Receiving member 4 Liquid reservoir part 5 Dripping prevention 6 Holder 7 Lower receiver 8 Pressing pin 9 Posture holder 10 Pay-out roll 11 Take-up roll P Base material

Claims

1. A coating device for applying paint to a substrate moving vertically upward or downward, comprising: A coating roll, a doctor roll, and a receiving member are provided, the applicator roll and the doctor roll are in contact with each other; The coating roll is a solid roll having no cells on its outer circumferential surface, the doctor roll is an engraved roll having cells on its outer circumferential surface, The receiving member is in contact with the doctor roll. A coating device comprising:

2. 2. The coating apparatus according to claim 1, A coating roll, a doctor roll and a receiving member are provided on both sides of the substrate. A coating device comprising:

3. The coating apparatus according to claim 1 or 2, Either or both of the application roll and the doctor roll are rubber rolls. A coating device comprising:

4. The coating apparatus according to claim 1 or 2, A holder for holding and moving the substrate is provided. A coating device comprising:

5. In the coating device according to claim 4, The holder holds the substrate by clamping both widthwise ends of the substrate. A coating device comprising:

Images