JP7699400B2 - Coating Equipment - Google Patents

Description

The present invention relates to a coating device used to apply paint to a substrate.

Resist paint, conductive paint, insulating paint, protective paint, reinforced paint, UV light blocking paint, antistatic paint, colored paint, functional coating agents, etc. (hereinafter collectively referred to as "paints") may be applied to the surface of a substrate, film, sheet, plate, panel, etc. (hereinafter collectively referred to as "base material"). Examples include applying resist to a printed wiring board or applying adhesive to copper foil.

Conventionally, a known device for applying paint to a substrate is equipped with an applicator roll that applies paint to the substrate, a doctor roll that supplies paint to the applicator roll, and a paint container that stores the paint (Patent Document 1). In this device, the paint in the paint container is picked up by the doctor roll, and the paint is transferred from the doctor roll to the applicator roll, and then transferred from the applicator roll to the substrate, thereby applying the paint to the substrate.

Patent No. 4074293

However, in the coating device, only the doctor roll is in direct contact with the paint, so the uniformity of the thickness of the paint applied to the substrate depends on the amount of paint that adheres to the doctor roll, the smoothness of the paint on the doctor roll surface, the amount of paint that transfers from the doctor roll to the coating roll, and the smoothness of the transferred paint.

For this reason, for example, if the paint on the doctor roll surface is not smooth, the paint will be transferred to the applicator roll surface unevenly, resulting in an uneven thickness of the paint film transferred to the substrate.

The smoothness of the coating applied to the substrate affects the mounting density of electronic components, so it is said that it is desirable for the coating to be as smooth as possible. With the advent of the 5G era and the increasing density of circuit boards, this demand has become greater than ever.

The present invention was made in consideration of the above circumstances, and the problem to be solved is to provide a coating device that can form a coating film with superior smoothness compared to conventional coating devices.

The coating device of the present invention is a coating device that applies paint to a substrate, and is equipped with a coating roll, a doctor roll, and a receiving member. In the coating device of the present invention, a liquid pool is formed by the receiving member, coating roll, and doctor roll so that the paint adheres to the coating roll and doctor roll.

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

FIG. 1 is a perspective view showing an example of a coating apparatus of the present invention. FIG. 2 is an explanatory diagram of a coating roll, a doctor roll, and a receiving member of the coating device in FIG. 1 . FIG. 4A is an explanatory diagram showing an example of a holder, and FIG. 4B is an explanatory diagram showing another example of the holder. FIG. 2 is an explanatory diagram showing an example of a case where a substrate is moved by roll-to-roll. FIG. 13 is an explanatory diagram showing an example of a case where a doctor roll is provided at a lower position than a coating roll. FIG. 13 is an explanatory diagram showing an example in which a coating roll, a doctor roll, and a receiving member are provided at different heights. 2A to 2D are front views illustrating an example of the operation of the coating device shown in FIG. 1 . 2A to 2D are side views illustrating an example of the operation of the coating device shown in FIG. 1 . 5A and 5B are front views illustrating an example of the operation of the coating device shown in FIG. 4 . 5A and 5B are side views illustrating an example of the operation of the coating apparatus shown in FIG. 4 .

(Embodiment 1)
An example of an embodiment of the coating device of the present invention will be described with reference to the drawings. As an example, the coating device shown in Fig. 1 is a device for coating a substrate P with paint, and includes a coating roll 1, a doctor roll 2, and a receiving member 3. In this embodiment, a liquid pool 4 is formed by the receiving member 3, the coating roll 1, and the doctor roll 2 so that the paint adheres to the coating roll 1 and the doctor roll 2. On both longitudinal outer sides of the coating roll 1 and the doctor roll 2, spill guards 5 are provided to prevent the paint pooled in the liquid pool 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 of the substrate P.

The coating roll 1 is a member for transferring paint to the substrate P to form a coating film. The coating roll 1 can be a rubber roll, a metal roll, or a roll with a DLC film on its outer periphery. Rubber rolls include natural rubber and synthetic rubber. Metal rolls include plated carbon steel.

In this embodiment, a solid roll without any irregularities (cells) on the outer circumferential surface is used as the coating roll 1, but in addition to a solid roll, an engraved roll with cells of various shapes, such as spiral grooves, single grooves, or dots, on the outer circumferential surface can also be used as the coating roll 1. The cell shapes are just examples and may be other shapes.

The applicator roll 1 in this embodiment is configured to rotate at all times, regardless of whether it is in contact with the substrate P or not. The applicator roll 1 rotates in the opposite direction to the direction of movement of the substrate P, specifically, as shown in FIG. 2, one applicator roll 1 (left side of the figure) rotates clockwise and the other applicator roll 1 (right side of the figure) rotates counterclockwise. The applicator roll 1 may also rotate in the opposite direction (forward relative to the direction of movement of the substrate P). In either case, it is configured to rotate in the opposite direction to the rotation of the doctor roll 2 with which it is in contact.

The doctor roll 2 is a member that supplies paint to the applicator roll 1 and smoothes (levels) the paint on the surface of the applicator roll 1. The doctor roll 2 can be a metal roll, a rubber roll, or a roll with a DLC film on its outer periphery. Rubber rolls include natural rubber and synthetic rubber. Metal rolls include plated carbon steel.

In this embodiment, the doctor roll 2 is a metal roll made of carbon steel with a DLC film on the outer periphery. Although not shown in the figure, the outer periphery of the doctor roll 2 is provided with irregularities (cells) of various shapes, such as spiral grooves, single grooves, and dots. The cell shapes are just examples and may be other shapes. A solid roll without cells can also be used as the doctor roll 2.

In this embodiment, the applicator roll 1 and doctor roll 2 have the same diameter and length. The applicator roll 1 and doctor roll 2 may also have different diameters and lengths. However, it is preferable to use a doctor roll 2 with a larger diameter than the applicator roll 1. By using a doctor roll 2 with a larger diameter than the applicator roll 1, the part of the doctor roll 2 with the paint attached is always in contact with the applicator roll 1 while the applicator roll 1 makes one revolution, which makes it easier to make the paint uniform on the outer peripheral surface of the applicator roll 1.

The receiving member 3 is a member that forms a liquid pool 4 between the applicator roll 1 and the doctor roll 2. In this embodiment, the receiving member 3 is a flat plate member that is longer than the applicator roll 1 and the doctor roll 2. The receiving member 3 can be made of metal, resin, rubber, etc.

As shown in Figure 2, the receiving member 3 in this embodiment is large enough to span both the application roll 1 and the doctor roll 2. The receiving member 3 is obliquely installed so that the angle α between the virtual axis (shown by a two-dot chain line in Figure 2) parallel to the straight line in the direction of movement of the vertically moving substrate P and the lower end side of the receiving member 3 is about 40 degrees. This angle can be adjusted as appropriate.

In this embodiment, the applicator roll 1 and doctor roll 2 are in contact, and the applicator roll 1 and the receiving member 3 are in contact, forming a pool 4 where paint accumulates. Specifically, the pool 4 is formed between the receiving member 3 and the applicator roll 1 and between the doctor roll 2 and the paint accumulated in the pool 4 is arranged to adhere to both the applicator roll 1 and the doctor roll 2.

In this embodiment, when the paint stored in the liquid pool 4 is directly applied to the applicator roll 1, the applicator roll 1 itself can pick up the paint, so even if the amount of paint transferred from the doctor roll 2 is small, uneven application of the paint to the substrate P is unlikely to occur, and a smooth coating film can be formed on the surface of the substrate P.

In this embodiment, the doctor roll 2 is positioned outside and higher than the applicator roll 1. This positional relationship has the advantage that the paint adhering to the applicator roll 1 does not fall off due to gravity, and the paint can be reliably transferred to the substrate P. In addition, because the distance from the contact point with the doctor roll 2 to the substrate P is shortened, there is the advantage that even when applying paint that is prone to volatilization, the paint can be transferred to the substrate P before it volatilizes.

The coating device of this embodiment includes a coating roll 1, a doctor roll 2, and a receiving member 3, as well as a holder 6, a lower receiving device 7, a pressing pin 8, and a position maintaining device 9. Note that the holder 6, the lower receiving device 7, the pressing pin 8, and the position maintaining device 9 may be provided as necessary, and any of them may be omitted or replaced by other means.

The holder 6 is a member that holds the substrate P and moves it in the vertical direction. In this embodiment, the holder 6 is a clip-shaped member that clamps the upper part of the substrate P. The holder 6 is configured to be raised and lowered by a lifting device (not shown). As shown in Figures 1 and 3(a), this embodiment shows an example in which there are three holders 6, but the number of holders 6 may be more or less than three.

When holding a soft substrate such as a flexible board, a holder 6 as shown in FIG. 3(b) can be used to clamp both ends of the substrate P in the width direction in order to prevent the substrate P from wobbling. This holder 6 has a length that allows it to clamp the entire length or nearly the entire length of the substrate P in the length direction. Other holders can also be used as the holder 6.

The lower support 7 is a member that supports the substrate P from below after it has been lowered to a predetermined position. In this embodiment, an upwardly-facing U-shaped trough-like member that is longer than the width of the substrate P is used as the lower support 7. The lower support 7 is positioned lower than the application roll 1, the position holder 9, and the pressing pin 8. The lower support 7 is positioned so that when the substrate P reaches the lower support 7, the vicinity of the upper end of the substrate P is at approximately the same height as the application roll 1.

The pressing pins 8 are pin-shaped members that temporarily press down both sides of the substrate P that has been lowered to a predetermined position. In this embodiment, the pressing pins 8 are configured to move in a direction toward the substrate P and in a direction away from the substrate P by a driving means (not shown). In this embodiment, as an example, two pressing pins are provided on the outside of each side of the substrate P (four in total), but the number of pressing pins 8 may be more or less than four.

The posture holder 9 is a member for contacting or being in close proximity to both sides of the substrate P to hold the upright posture of the substrate P. In this embodiment, the posture holder 9 is a rectangular block made of rubber. In this embodiment, two posture holders 9 are provided on the outside of one side of the substrate P, and two on the outside of the other side (four in total). As shown in Figures 3(a) and (b), the posture holders 9 on the outside of each side are provided at intervals in the width direction of the substrate P. The number of posture holders 9 can be more or less than four.

In this embodiment, each of the position holders 9 is configured to move in a direction toward and away from the substrate P by a driving means (not shown). Although each of the position holders 9 can be configured to move individually, in this embodiment, the two position holders 9 that hold down the same surface of the substrate P are configured to move in a synchronized manner.

In this embodiment, the attitude maintaining device 9 is moved separately from the applicator roll 1, doctor roll 2, and receiving member 3, but the attitude maintaining device 9 may be moved in synchronization with the applicator roll 1, doctor roll 2, and receiving member 3. Each attitude maintaining device 9 may also be fixed in a certain position without moving.

Each attitude retainer 9 is provided below the applicator roll 1. The attitude retainers 9 can be provided so as to be in contact with the applicator roll 1, or can be provided away from it. When provided so as to be in contact with the applicator roll 1, the upper surface of the attitude retainer 9 can be recessed in an arc shape to follow the outer circumference of the applicator roll 1.

In this embodiment, the posture retainer 9 is made of rubber, but the posture retainer 9 may be made of a material other than rubber. In either case, it is preferable to use a material with low friction resistance so as not to impede the smooth movement (rising and lowering) of the substrate P when the coating is applied by the coating roll 1. The posture retainer 9 can also be shaped to have a small contact area so as not to impede the smooth ascent of the substrate P. In addition, at least the contact surface of the posture retainer 9 may be treated with a fluororesin to reduce friction resistance.

In this embodiment, the paint is applied while the substrate P is raised, but as shown by the dashed line in FIG. 2, the paint can also be applied while the substrate P is lowered. In this case, the coating roll 1 can rotate in the opposite direction to the movement of the substrate P, or in the forward direction to the movement of the substrate P.

(Embodiment 2)
Another embodiment of the coating device of the present invention will be described with reference to the drawings. The basic configuration of the coating device of this embodiment is the same as that of the first embodiment. The difference is in the method of moving the substrate P. In the above embodiment, the substrate P is held by the holder 6 and moved in the vertical direction (when the substrate P is a sheet), but the coating device of the present invention can also be configured to apply paint to the substrate P moving in a roll-to-roll manner as shown in FIG. 4.

Specifically, as shown in FIG. 4, the pay-out roll 10 and the take-up roll 11 are arranged at a distance in the vertical direction, and the substrate P is paid out from the pay-out roll 10 and taken up by the take-up roll 11.

In the example shown in Figure 4, the pay-out roll 10 is provided on the lower side and the take-up roll 11 is provided on the upper side, but the pay-out roll 10 and the take-up roll 11 can also be reversed upside down, and the paint can be applied while the substrate P is moved downward as shown by the dashed line in Figure 4.

Even in the case of the configuration shown in FIG. 4, the coating roll 1, doctor roll 2, and receiving member 3 can be the same as those in the first embodiment. Note that, when the substrate P is moved by a roll-to-roll method, the holder 6, lower receiving member 7, pressing pin 8, and attitude holder 9 can be omitted.

Other Embodiments
In both of the above-described embodiments, the application roll 1 and the doctor roll 2 have the same diameter, but it is possible to use rolls with different diameters for the application roll 1 and the doctor roll 2. Also, in the above-described embodiments, the application roll 1 and the doctor roll 2 have the same length, but it is possible to use rolls with different lengths for the application roll 1 and the doctor roll 2.

In both of the above embodiments, a solid roll is used as the coating roll 1 and an engraved roll is used as the doctor roll 2, but it is also possible to use an engraved roll as the coating roll 1 and a solid roll as the doctor roll 2. Also, if possible, both the coating roll 1 and the doctor roll 2 may be solid rolls or engraved rolls.

In both of the above embodiments, a rubber roll is used as the applicator roll 1 and a metal roll (carbon steel with a DLC film formed) is used as the doctor roll 2, but it is also possible to use the metal roll as the applicator roll 1 and a rubber roll as the doctor roll 2. Also, if possible, both the applicator roll 1 and the doctor roll 2 may be metal rolls or rubber rolls.

Metal rolls that can be used include, for example, stainless steels in general, such as austenitic and martensitic stainless steels such as SUS304 and SUS440C, carbon steels such as STKM13A and S25C with HC or Ni plating on the surface, and stainless steels, carbon steels, or HCr-plated surfaces with DLC coating applied.

In both of the above embodiments, the doctor roll 2 is positioned higher than the applicator roll 1, but the doctor roll 2 can also be positioned lower (at a lower location) than the applicator roll 1, as shown in FIG. 5. In this case, the doctor roll 2 located to the left of the substrate P in the figure rotates clockwise, and the applicator roll 1 rotates counterclockwise. On the other hand, the doctor roll 2 located to the right of the substrate P in the figure rotates counterclockwise, and the applicator roll 1 rotates clockwise. This configuration is easy to adopt when the viscosity of the paint is high enough that it does not fall due to gravity.

Although not explained in both of the above embodiments, the doctor roll 2 can be made to move in the direction in which the applicator roll 1 is pressed and in the opposite direction (the direction in which the pressing is released). Similarly, the applicator roll 1 can be made to move in the direction in which the substrate P is pressed and in the opposite direction (the direction in which the pressing is released).

In both of the above embodiments, the coating roll 1, doctor roll 2, and receiving member 3 are provided at the same height on both sides of the substrate P, but as shown in FIG. 6, the coating roll 1, doctor roll 2, and receiving member 3 can also be provided at different heights on both sides of the substrate P. This configuration is easy to adopt when the substrate P is soft, such as a film or copper foil.

In both of the above embodiments, the case where the spill guard 5 is provided on both the longitudinal outer sides of the application roll 1 and the doctor roll 2 is taken as an example, but the spill guard 5 can also be omitted by adding a structure equivalent to the spill guard 5 to the receiving member 3.

The present invention is not limited to the structure and shape of the above-described embodiments, and various modifications and variations are possible without departing from the spirit of the invention.

Next, the operation of the coating device of the present invention will be described with reference to the drawings. Here, as an example of the operation of the coating device of the present invention, the operation of the coating device of the first embodiment and the operation of the coating device of the second embodiment will be described.

The coating device of the first embodiment operates as follows: In Fig. 7(a) to (d) and Fig. 8(a) to (d), the holder 6, the pressing pin 8, and the attitude holder 9 are shown in solid lines when they are in contact with or close to the substrate P, and shown in two-dot chain lines when they are not in contact with or close to the substrate P.
(1) The substrate P held by the holder 6 is set at a predetermined position (FIGS. 7(a) and 8(a)).
(2) The substrate P held by the holder 6 is lowered to a predetermined position and supported by the lower support 7 (FIGS. 7(b) and 8(b)).
(3) The pressing pins 8 come into contact with both sides of the substrate P, and the substrate P is held (FIGS. 7(c) and 8(c)). At this time, the substrate P is released from the clamping device 6 just before the substrate P is held by the pressing pins 8. In addition, the posture holders 9 approach or come into contact with both sides of the substrate P, and the upright posture of the substrate P is held.
(4) The coating rolls 1 on both sides of the substrate P come into contact with the substrate P, and the coating material held on the surfaces of the coating rolls 1 is transferred to the substrate P (FIGS. 7(d) and 8(d)). At this time, the upper end of the substrate P is again clamped by the holders 6, and the substrate P is pulled up, and the coating material on the surfaces of the coating rolls 1 is transferred to the pulled up substrate P. Just before the coating rolls 1 come into contact with the substrate P, the holding of the substrate P by the presser pins 8 is released.

The coating device of the second embodiment operates as follows.
(1) The substrate P held by the pay-out roll 10 and the take-up roll 11 is set at a predetermined position (FIG. 9(a) and FIG. 10(a)).
(2) The coating roll 1 comes into contact with both sides of the substrate P which moves from the side of the feeding roll 10 to the side of the winding roll 11 due to the action of the feeding roll 10 and the winding roll 11, and the coating material held on the surface of the coating roll 1 is transferred to the substrate P (Figures 9(b) and 10(b)).

In both of the above operations, the paint applied to the substrate P from the applicator roll 1 is a mixture of paint supplied from the doctor roll 2 and paint picked up by the applicator roll 1 itself, and is leveled to a specified thickness as it passes through both rolls.

As described above, in the coating device of each of the above embodiments, not only is the paint supplied from the doctor roll 2 to the coating roll 1, but the coating roll 1 is configured to pick up the paint itself, so the amount of paint adhering to the coating roll 1 tends to be stable, and a smooth coating film can be formed on the substrate P.

The coating device of the present invention can be used to apply paint to various substrates P, and is particularly suitable for applying resist to printed wiring boards such as rigid boards and flexible boards, and for applying adhesive to copper foil.

REFERENCE SIGNS LIST 1 Coating roll 2 Doctor roll 3 Receiving member 4 Liquid pool 5 Spill guard 6 Holder 7 Lower support 8 Presser pin 9 Position holder 10 Pay-out roll 11 Take-up roll P Substrate

Claims (5)

In a coating device for coating a substrate moving vertically upward or downward ,
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. 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: 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: The coating apparatus according to claim 1 or 2,
A holder for holding and moving the substrate is provided.
A coating device comprising: 5. The coating apparatus according to claim 4 ,
The holder holds the substrate by clamping both widthwise ends of the substrate.
A coating device comprising:

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