JP6986713B2 - Double-sided coating method and double-sided coating equipment - Google Patents

Description

The present invention relates to a double-sided coating method for applying a coating liquid to both sides of a base material and an apparatus thereof.

A double-sided coating base material in which a coating liquid is applied to both sides of a base material serving as a core is used as an electrode for a secondary battery, a fuel cell, or the like.

The manufacturing process of the double-sided coating base material includes a step of applying a coating liquid containing an active material to the upper surface of the base material by a first die head, and a coating process containing an active material substantially at the same time as this step. A step of applying the liquid to the lower surface of the base material by a second die head, a step of transporting the double-sided coated base material to a drying device to dry both coated surfaces, and a step of winding up the double-sided coated base material. It consists of a process.

Regarding the transportation of the double-sided coated base material, since the coated surface is in a wet state after the coating on both sides is completed until the drying of the coated surface is completed, the base material is supported by a long roll or the like. I can't.

Therefore, in addition to the method of gripping both edges of the base material with an inclined pressing roller or a plate-shaped member (Patent Document 1), and gripping both edges of the base material with an inclined pressing roller. A method of supporting the base material with a coating portion of a coating die head (Patent Document 2) is known.

Japanese Unexamined Patent Publication No. 2001-316006 WO2011 / 001648A1

However, although these methods have a certain effect of suppressing the fluttering and wrinkles of the base material, the point that the base material after coating bends due to the weight of the coating liquid cannot be sufficiently suppressed. ..

In particular, when manufacturing a wide double-sided coating base material that exceeds 1 m, which is desired to achieve high productivity, and double-sided coating under thick coating conditions, which is desired for increasing the capacity of batteries. When the base material is manufactured, the bending of the base material after coating becomes remarkable.

FIG. 11A shows a state of the double-sided coating device before coating.

In this double-sided coating device, the base material 4 drawn out from the winding body 40 and transferred via the backup roll 7 and the base material support device 3 is a drying device provided in the subsequent stage of the base material support device 3. The double-sided coating base material that has passed through 6 and is completed is wound on the take-up reel 41. At the position of the backup roll 7, a first die head 1 for applying a coating liquid to the upper surface of the base material 4 is provided. At a position between the backup roll 7 and the base material support device 3, a second die head 2 for applying a coating liquid to the lower surface of the base material 4 is provided. FIG. 11B shows a cross-sectional view of the base material support device 3 at the position. FIG. 11C shows a cross-sectional view at the position of the second die head 2. X indicates a coating gap which is a gap between the second die head 2 and the base material 4. A is a top surface coated portion coated by the first die head 1, and B is a bottom surface coated portion coated by the second die head 2.

FIG. 12A shows a state during continuous intermittent coating. FIG. 12B shows a cross-sectional view at the position of the base material support device 3. FIG. 12 (c) shows a cross-sectional view at the position of the second die head 2. FIG. 12D shows a detailed view of the cross-sectional shape of the lower surface coating film in the coating width direction after coating.

As shown in FIGS. 11A and 11B, in the state before coating, the tension in the flow direction is adjusted while gripping both edges of the base material 4 with the pressing rollers 3a and 3b of the base material support device 3. By doing so, the base material 4 does not bend in both the flow direction and the width direction of the base material 4, and as shown in FIG. 11C, the coating gap X that affects the coating weight accuracy in the width direction is the coating width. It is constant in the direction.

However, when the coating is continued as shown in FIGS. 12A and 12B, both edges of the substrate 4 are pressed by the rollers 3a and 3b against the increase in the weight of the substrate due to the coated coating liquid. By simply adjusting the tension in the flow direction while gripping, it becomes difficult to convey the base material 4 while maintaining the same height as before coating, and the base material 4 is based in both the flow direction and the width direction of the base material. Deflection of the material 4 occurs.

As a result, the coating gap X, which affects the coating weight accuracy in the width direction, becomes narrow as shown in FIG. 12 (c) and becomes non-uniform in the coating width direction. Therefore, as shown in FIG. 12 (d). In addition, the coating weight accuracy in the width direction deteriorates. Specifically, there is a problem that the thickness of the central portion in the coating width direction is thinner than that of the vicinity of both ends.

13 and 14 show another example.

FIG. 13A shows a state before coating. In addition to gripping both edges of the base material 4 with the inclined pressing rollers 3a and 3b, the base material 4 is attached to the tip of the second die head 2. I support it at 20. 13 (a) and 13 (c) show cross-sectional views at positions aa and bb in FIG. 13 (a). FIG. 14 shows a state during continuous intermittent coating.

Even in this case, in the state before coating, the substrate 4 does not bend in both the flow direction and the width direction of the substrate 4 as shown in FIGS. 13 (a) and 13 (b), and as shown in FIG. 13 (c), the substrate 4 is coated. The work gap X is constant in the coating width direction.

However, even if both edges of the base material 4 are gripped by the inclined pressing rollers 3a and 3b and the base material 4 is supported by the tip 20 of the second die head 2, the bending of the base material 4 is slightly reduced. However, during continuous intermittent coating, the weight of the substrate increases due to the coated coating liquid, so as shown in FIG. 14, the substrate 4 has the same height as before coating. It becomes difficult to carry the base material 4 while maintaining it, and the bending of the base material 4 cannot be eliminated in both the flow direction and the width direction of the base material 4, and the influence on the coating gap X cannot be eliminated.

As a result, as in FIGS. 12 (b) and 12 (c), the coating gap X, which affects the coating weight accuracy in the width direction, becomes narrow and becomes non-uniform in the coating width direction. Therefore, FIG. 12 (d) Similarly, there is a problem that the accuracy of the coating weight in the width direction deteriorates and the thickness of the central portion in the coating width direction becomes thinner than that in the vicinity of both ends.

Further, in the methods shown in FIGS. 13 and 14, the tip 20 of the base material 4 and the second die head 2 is worn, and the wear powder becomes a foreign substance and adheres to the base material 4 to be mixed in the product, for example, a battery. Then, there is a problem that the risk of voltage failure, heat generation, and ignition due to an internal short circuit increases.

INDUSTRIAL APPLICABILITY The present invention provides a double-sided coating method that reduces the deflection of the substrate 4 that occurs during transport of the double-sided coating substrate and prevents deterioration of the coating weight accuracy in the width direction due to a change in the coating gap X of the second die head 2. The purpose is to provide.

Double side coating process of the present invention, by the first die head to apply the coating liquid on the upper surface of the base material, coating the coating liquid by the second die head to the lower surface of the substrate, the coating on the upper and lower surfaces A double-sided coating method for drying the base material coated with the working liquid, wherein the base material support device is arranged on the downstream side of the second die head and abuts and supports the lower surface of the base material. The gap between the second die head and the lower surface of the base material is set as the target coating gap, and the base material support device includes a first support member that abuts and supports the lower surface of the base material and a lower surface of the base material. In the double-sided coating method, the base material is supported and moved to the downstream side together with the base material from a specific position near the second die head. Before the one support member is separated from the base material, the second support member is brought into contact with the lower surface of the base material at the specific position, and the second support member supports the base material while being downstream. The coating liquid is applied to the lower surface of the base material by the second die head while moving toward the side, and the base material is applied at the timing when the coating by the second die head reaches the end of the lower surface coating portion. It is characterized in that the first support member that has moved to the downstream side is raised to a height exceeding the transfer height of the base material.

In the double-sided coating method of the present invention, the coating liquid is applied to the upper surface of the base material by the first die head, the coating liquid is applied to the lower surface of the base material by the second die head, and the coating liquid is applied to the upper surface and the lower surface. A double-sided coating method for drying the base material coated with the working liquid, wherein the base material support device is arranged on the downstream side of the second die head and abuts and supports the lower surface of the base material. The gap between the second die head and the lower surface of the base material is set as the target coating gap, and the base material support device includes a first support member that abuts and supports the lower surface of the base material and a lower surface of the base material. In the double-sided coating method, the base material is supported and moved to the downstream side together with the base material from a specific position near the second die head. Before the one support member is separated from the base material, the second support member is brought into contact with the lower surface of the base material at the specific position, and the second support member supports the base material while being downstream. While moving toward the side, the coating liquid is applied to the lower surface of the base material by the second die head, and the coating of the lower surface coating portion by the second die head is started and the end of the lower surface coating portion is reached. It is characterized in that the first support member that has moved downstream together with the base material is raised to a height exceeding the transfer height of the base material in the period until the base material is reached.

Specifically, it is preferable that the support member of the base material support device abuts on the lower surface uncoated portion formed between the lower surface coated portions of the base material to support the base material.

The double side coating device of the present invention, by the first die head to apply the coating liquid on the upper surface of the base material, coating the coating liquid by the second die head to the lower surface of the substrate, the upper and lower surfaces the substrate coating solution was applied by a double side coating device for drying, it is arranged downstream of the second die head, substrate for supporting the substrate in contact with the lower surface of the substrate A support device is provided, and the base material support device moves downstream together with the base material so that the gap between the second die head and the lower surface of the base material becomes a target coating gap, and the transfer height of the base material is provided. It is characterized in that the base material can be raised to a height exceeding the height.

According to this configuration, the coating liquid is applied to the lower surface of the base material by the second die head while moving toward the downstream side while supporting the base material by the base material support device, so that the base material generated during transportation is supported. It is possible to realize high-quality simultaneous double-sided coating that reduces bending and prevents deterioration of coating weight accuracy in the width direction due to changes in the coating gap of the second die head.

A schematic view showing (a) the whole of a double-sided coating apparatus for executing the double-sided coating method of the present invention and (b) a plan view showing a transport portion thereof. Operation process diagram of the double-sided coating device of the same embodiment Detailed view of the coating liquid pool at the tip of the die head and the behavior of the base material when the discharge of the coating liquid of the second die head is stopped at the time of intermittent in the same embodiment. The operation process diagram which pushes up the support member when the discharge of a coating liquid is stopped at the time of intermittent coating of this invention. (A) Figure when tailing occurs and (b) Figure in good condition without tailing Operation process diagram of the support member that supports the lower surface unpainted part where the upper surface is coated when the coating end part position of the upper surface coated part and the lower surface coated part are different. Operation process diagram of the support member that supports the lower surface unpainted part where the upper surface is not coated when the coating end part position of the upper surface coated part and the lower surface coated part are different. Operation process diagram in which the support member is pushed up when the coating is stopped while supporting the uncoated portion on the lower surface where the upper surface is coated when the positions of the coating end portions of the upper surface coated portion and the lower surface coated portion are different. Operation process diagram in which the support member is pushed up when the coating is stopped while supporting the uncoated portion on the lower surface where the upper surface is not coated when the positions of the coating end portions of the upper surface coated portion and the lower surface coated portion are different. Operation flow diagram that pushes up the support member during the coating of the lower surface (A) A side view of the coating process before coating in the prior art in which both edges of the base material are gripped by the inclined pressing rollers 3a and 3b, (b) a cross-sectional view at positions aa, and (c). Sectional view at position b-bb (A) Side view of the coating process during continuous coating in FIG. 11 (a), (b) cross-sectional view at position aa, (c) cross-sectional view at position bb-, and (d) bottom surface coating. Cross-sectional view of the film in the coating width direction (A) Side view of another conventional example before coating, (b) sectional view at position aa, and (c) sectional view at position bb. Side view during continuous coating according to FIG.

Hereinafter, the double-sided coating method of the present invention will be described based on specific embodiments.

(Embodiment 1)
1 (a) and 1 (b) show a double-sided coating apparatus for carrying out the double-sided coating method of the present invention.

In this double-sided coating device, a coating liquid is applied to both surfaces of a base material 4 which is a core body of electrodes such as a secondary battery and a fuel cell.

From the upstream side to the downstream side in the transport direction, the backup roll 7, the first die head 1 for coating the upper surface of the base material 4, the second die head 2 for coating the lower surface of the base material 4, and the base material 4 It has a base material support device 3 and a drying device 6 that are in contact with the lower surface and define a coating gap X that is a gap between the second die head 2 and the lower surface of the base material 4. The backup roll 7 and the first die head 1 face each other in the horizontal direction. The base material 4 pulled out from the winding body 40 is moved from below to the facing portion between the backup roll 7 and the first die head 1, is further turned by the backup roll 7, and then moved horizontally. Be done. The first die head 1 coats the upper surface of the base material 4 with a coating liquid containing an active substance. The second die head 2 coats the lower surface of the base material 4 with a coating liquid containing an active substance.

The base material support device 3 has first and second support members 30a and 30b that are transferred toward the drying device 6 together with the base material 4 while abutting against and supporting the lower surface of the base material 4. As shown in FIG. 1B, the first and second support members 30a and 30b are rolls longer than the width of the base material 4.

Inside the drying device 6, gas injection nozzles 60 for ejecting a gas for drying the coated surface are provided at the top and bottom, and the double-sided coated base material 4 is suspended by the ejected gas on the downstream side. Dry while transporting to. The double-sided coated base material 4 dried by the drying device 6 is wound on a take-up reel 41.

FIG. 2 shows the operation process.

In the double-sided coated base material to be produced in the first embodiment, the upper surface coating portion A is formed on the upper surface of the base material 4 as shown in step S5 of FIG. 2, and the lower surface is formed on the lower surface of the base material 4. The coated portion B is formed, the lengths of the upper surface coated portion A and the lower surface coated portion B are the same, and the region of the upper surface coated portion A and the region of the lower surface coated portion B are completely formed via the base material 4. overlapping. The upper surface coated portion A and the lower surface coated portion B are manufactured by opening the upper surface uncoated portion A and the lower surface uncoated portion B in the longitudinal direction of the base material 4 and repeatedly coating them, and drying them with the drying device 6. Has been done.

In step S1 of FIG. 2, the starting end of the upper surface coating portion A in which the coating liquid is applied to the upper surface of the base material 4 by the first die head 1 approaches the position of the second die head 2, and is based on the second die head 2. Before or at the same time as the timing to start coating the coating liquid on the lower surface of the material 4, on the lower surface uncoated portion C immediately after the lower surface coating portion B coated immediately before or at the downstream side of the second die head 2. The first support member 30a abuts and supports the base material 4 over the width direction. The position where the first support member 30a abuts on the downstream side of the second die head 2 is referred to as a specific position.

In this state, the coating of the lower surface coating portion B by the second die head 2 is started while moving the base material 4 to the downstream side. The first support member 30a moves downstream together with the base material 4 at the same speed as the base material 4. By supporting the base material 4 by the first support member 30a, the gap between the second die head 2 and the lower surface of the base material 4 is maintained at the target coating gap X0 even during the subsequent movement of the base material 4 to the downstream side. ..

Then, from the time of step S2 when the end of the lower surface coated portion B being coated by the second die head 2 is reached, the coating by the second die head 2 is stopped and the next lower surface uncoated portion C is formed as in step S3. Even so, the first support member 30a moves to the downstream side with the transfer of the base material 4.

Before or at the same time as the start end of the next lower surface coating portion C reaches the position of the second die head 2 and the second die head 2 starts coating the lower surface of the base material 4 with the coating liquid, as in step S4. The second support member 30b abuts on the lower surface uncoated portion C arriving at the specific position immediately after the downstream side of the second die head 2 to support the base material 4 over the width direction. At this point, even when the second support member 30b is in contact with the base material 4, the first support member 30a is in contact with the lower surface coating portion C at the tip of the base material 4.

As shown in steps S4 to S5, while the base material 4 is supported by the first support member 30a and the second support member 30b, the first support member 30a and the second support member 30b are downstream at the same speed as the base material 4. After moving to the side and starting coating on the lower surface of the base material 4 by the second die head 2, the first support member 30a descends and separates from the base material 4. The first support member 30a separated from the base material 4 returns to a specific position near the second die head 2 and stands by in preparation for the next step S1 of coating.

Like the first support member 30a, the second support member 30b is separated from the base material 4 in the next step S5 and returns to a position closer to the second die head 2. The second support member 30b may support the base material 4 before or at the same time as the next coating is started.

By repeating the operations of steps S1 to S5, the coating liquid is applied to the lower surface of the base material 4 by the second die head 2 while supporting the base material 4 by the first and second support members 30a and 30b. Continuously stable transportation and coating are possible without bending of the material 4.

FIG. 3 shows a pool of coating liquid at the tip of the die head when the discharge of the coating liquid of the second die head 2 is stopped in the lower surface uncoated portion C due to the intermittent coating in steps S2 to S4 of FIG. The details regarding the behavior of 8 and the base material 4 are shown.

As shown in FIG. 3A, when the discharge of the coating liquid from the second die head 2 is stopped at the time of intermittent coating, the coating liquid coated on the base material 4 and the tip portion of the second die head 2 are coated. The work liquid reservoir 8 is separated.

At the same time, as shown in FIGS. 3 (b) and 3 (c), the base material 4 is once drawn into the tip of the second die head 2 when the coating liquid pool 8 tries to shrink due to surface tension. After the coating liquid coated on the base material 4 and the coating liquid reservoir 8 are separated, the base material 4 tries to return to the original state, and the second die head 2 is virtually shown in FIG. 3 (d). The base material 4 near the upper part of the tip portion vibrates up and down.

After that, as shown in FIG. 3 (e), the vibration of the base material 4 is caused by abutting and supporting the lower surface uncoated portion C of the base material 4 by the first support member 30a or the second support member 30b. It can be stopped.

As a result, the second support member 30b supports the base material 4 before the next coating is started, so that the vibration of the base material 4 generated at the time of intermittent coating is suppressed by the base material support device 3 and then applied. It is possible to start the construction and further stabilize the coating.

(Embodiment 2)
In the first embodiment, the first support member 30a moves together with the base material 4 in steps S2 to S4 of FIG. 2A, and the first support member 30a is the base material 4 in steps S1 and S2. However, in the second embodiment, the coating quality is further improved by raising and lowering the first support member 30a so as to exceed the transfer height H0 of the base material 4. ..

FIG. 4 shows an operation flow diagram for pushing up the first support member 30a (or the second support member 30b) when the discharge of the coating liquid is stopped at the time of intermittent coating.

Step S1 and step S2 are the same as steps S1 and S2 of the first embodiment. Step S3-1 and step S3-2 of FIG. 4 are different from step S3 of the first embodiment. Steps S4 and S5 of FIG. 4 are the same as steps S4 and S5 of the first embodiment.

In step S3-1 of FIG. 4, at the timing when the coating by the second die head 2 reaches the end of the lower surface coating portion B, the first support member 30a which has moved to the downstream side together with the base material 4 in step S2 is The base material 4 is raised to a height H1 exceeding the transfer height H0 in steps S1 and S2 by a lifting mechanism (not shown), and moves downstream together with the base material 4.

In step S3-2, the first support member 30a is lowered to the transfer height H0 of the base material 4 and returned by the time the start end of the lower surface coating portion B next to the base material 4 reaches the second die head 2.

By doing so, the coating gap X in the state where the coating by the second die head 2 reaches the end of the lower surface coating portion B can be temporarily widened as compared with the case of the first embodiment. As a result, the liquid sharpness of the coating end portion 9 can be improved, so that an effect of suppressing coating defects such as tailing of the coating liquid can be obtained.

Here, the case of the first support member 30a has been described, but the same applies to the case of the second support member 30b.

"Tailing of the coating liquid" will be described by comparing FIGS. 5 (a) and 5 (b).

FIG. 5A shows a good state in which the tailing coating defect does not occur, and FIG. 5B shows a good state in which the tailing coating defect does not occur. For example, when coating a electrode plate with a thick coating thickness and a heavy coating weight, which is desired for increasing the capacity of a battery, or when the coating conditions are such that the coating speed is high in order to achieve high productivity. As shown in FIG. 5A, when the liquid sharpness at the end of the lower surface coated portion B deteriorates, a tailing defect 5 occurs in the lower surface uncoated portion C.

In such a case, as in the second embodiment, the first support member 30a or the second support member 30b is raised to a height H1 that exceeds the transfer height H0 of the base material 4 in step S3-1. As shown in FIG. 5B, it is possible to obtain a good coating state in which tailing does not occur.

(Embodiment 3)
In the first embodiment described above, the top surface coated portion A and the bottom surface coated portion B of the base material 4 have the same length, and the region of the top surface coated portion A and the bottom surface coated portion B pass through the base material 4. Although the regions were completely overlapped, the same applies when the end position of the upper surface coating portion A and the end position of the lower surface coating portion B are different.

6 and 7 show that the starting end position of the upper surface coating portion A and the starting end position of the lower surface coating portion B on the base material 4 are the same, and the length of the lower surface coating portion B is shorter than the length of the upper surface coating portion A. Shows the case.

In steps S1 to S5 of FIG. 6, the first support member 30a or the second support member 30b abuts on the lower surface uncoated portion C adjacent to the lower surface coated portion B on the lower side of the upper surface coated portion A. It differs from steps S1 to S5 in FIG. 2 only in that it supports the base material 4.

In steps S1 to S5 of FIG. 7, the first support member 30a or the second support member 30b is brought into contact with the lower surface unpainted portion C below the upper surface unpainted portion D to support the base material 4. It differs from step S1 to step S5 in FIG. 2 only in that.

(Embodiment 4)
In the second embodiment described above, the top surface coated portion A and the bottom surface coated portion B of the base material 4 have the same length, and the region of the top surface coated portion A and the bottom surface coated portion B pass through the base material 4. Although the regions were completely overlapped, the same applies when the end position of the upper surface coating portion A and the end position of the lower surface coating portion B are different.

8 and 9 show that the starting position of the upper surface coating portion A and the starting end position of the lower surface coating portion B on the base material 4 are the same, and the length of the lower surface coating portion B is shorter than the length of the upper surface coating portion A. Another example is shown.

In steps S1 to S5 of FIG. 8, the first support member 30a or the second support member 30b is brought into contact with the lower surface uncoated portion C adjacent to the lower surface coated portion B under the upper surface coated portion A. It differs from steps S1 to S5 in FIG. 4 only in that it supports the base material 4.

In steps S1 to S5 of FIG. 9, the first support member 30a or the second support member 30b is brought into contact with the lower surface unpainted portion C below the upper surface unpainted portion D to support the base material 4. It is different from steps S1 to S5 in FIG. 4 only in that respect.

As shown in FIGS. 6 to 9, for example, even when the coating end positions of the upper surface and the lower surface are not the same from the design surface of the battery, the position of supporting the base material 4 from the lower surface is the coating of the upper surface. The same effects as those of the first and second embodiments can be obtained regardless of the presence or absence.

However, when supporting the uncoated portion on the lower surface where the upper surface is coated, the weight of the coating liquid on the upper surface coating portion is higher than when supporting the uncoated portion on the lower surface where the upper surface is not coated. As a result, the load applied to the support mechanism 3 becomes large. For this reason, considering the need to increase equipment costs by ensuring equipment strength based on long-term operation at high speed, the unpainted lower surface portion whose upper surface is not coated is designated as the first support member 30a or the first support member 30a. (Ii) It is desirable to support with the support member 30b.

(Embodiment 5)
In the second embodiment, the first support member 30a or the second support member 30b is raised to a height H1 exceeding the transfer height H0 of the base material 4 at the timing when the coating of the lower surface coating portion B is completed. By raising the first support member 30a or the second support member 30b to a height H1 that exceeds the transfer height H0 of the base material 4 during the coating of the coating portion B, the coating weight accuracy does not deteriorate. High quality simultaneous double-sided coating can be achieved.

When the coating conditions are thick and heavy, which is desired for increasing the capacity of batteries, or when the coating speed is high and the tension applied to the base material is high, which is desired to achieve high productivity. FIG. 10 shows a process suitable for the condition.

Step S1 in FIG. 10 is the same as step S1 in FIG.

In step S2 of FIG. 10, the second die head 2 moves downstream together with the base material 4 during the period from when the second die head 2 starts coating the lower surface coating portion B until the second die head 2 reaches the end of the lower surface coating portion B. The first support member 30a or the second support member 30b is raised to a height H1 that exceeds the transfer height H0 of the base material 4, and the coating gap X is maintained at the target coating gap X0.

In step S3 of FIG. 10, since the base material 4 is not supported in the state of step S2 in which the first support member 30a or the second support member 30b is raised, the base material 4 is moved to the downstream side together with the base material 4 and the lower surface coating portion B is used. To paint.

In the section from steps S2 to S4 in FIG. 10, the first support member 30a or the second support member 30b that move downstream together with the base material 4 continues to be gradually increased from the transfer height H0 of the base material 4. May be.

In step S4 of FIG. 10, the second support member 30b or the first support member 30a rises before the first support member 30a or the second support member 30b descends from the height H1 and separates from the base material 4. Then, it comes into contact with the base material 4 having a height H0 immediately after the second die head 2.

In step S5 of FIG. 10, the first support member 30a or the second support member 30b is separated from the base material 4, and the first support member 30a or the second support member 30b separated from the base material 4 is subjected to the following coating. In preparation for step S1 of the above step S1, the device returns to a position closer to the second die head 2 and stands by.

As a result, it is possible to prevent the load due to the weight of the coating liquid and the bending caused by the elongation of the base material 4 due to the tension applied to the base material 4 from affecting the coating gap X0, and the coating weight accuracy does not deteriorate. High quality simultaneous double-sided coating can be achieved.

(Example 1)
In the first embodiment shown in FIG. 2, a copper foil base material having a width of 1300 mm of the base material 4 has a wet film thickness of 200 μm, a coating length of 1 m, an uncoated portion length of 15 cm, and a coating speed of 35 m / min, 1000 m. The maximum film thickness variation in the width direction when coated was 2.5%. As a comparative example, the maximum film thickness variation similarly carried out by the conventional technique shown in FIG. 11 was 7.5%.

In this way, by supporting the base material for a certain section while moving together with the base material 4 on the downstream side of the second die head 2, the coating gap X0 is continuously coated while being kept constant in the coating width direction. By doing so, it is possible to realize high-precision double-sided simultaneous coating.

(Example 2)
According to the second embodiment shown in FIG. 4, when the wet film thickness is 300 μm and the coating speed is 40 m / min in the same manner as in the first embodiment, in the second embodiment, the tailing of the coating liquid at the end of the coating is poor. The rate of occurrence was 0%, but the rate of defective coating liquid tailing at the end of coating in the prior art was 1.2%.

It should be noted that the tail pulling tends to occur more easily as the coating thickness increases and the coating speed increases. Further, as a quality judgment criterion, those having a tail pulling length Y = 1.5 mm in FIG. 5A were regarded as defective.

In this way, in the transport method having a mechanism for supporting the base material for a certain section while moving together with the base material 4 on the downstream side of the second die head 2, the movement is performed while supporting the base material at the timing when the coating is stopped. By pushing up the supporting member, the effect of improving the sharpness of the coating liquid can be obtained even under coating conditions where the film thickness is thick and the coating speed is high, and tailing failure occurs. It is possible to realize high-precision double-sided simultaneous coating.

The double-sided coating method of the present invention contributes to realizing a high capacity of the lithium ion secondary battery electrode plate at low cost.

1 1st die head 2 2nd die head 3 base material support device 30a 1st support member 30b 2nd support member 4 base material 5 tail pull 6 drying device 7 backup roll 8 coating liquid pool 9 coating end part A base material 4 Top surface coated part B Bottom surface coated part of base material 4 C Bottom surface uncoated part D Top surface uncoated part

Claims (4)

Apply the coating liquid to the upper surface of the base material with the first die head,
The coating liquid is applied to the lower surface of the base material by the second die head, and the coating liquid is applied.
It is a double-sided coating method for drying the base material on which the coating liquid is applied to the upper surface and the lower surface.
The second die head is disposed downstream of, the substrate supporting device for supporting in contact with the lower surface of the substrate, to set the gap between the lower surface of the substrate and the second die head to the target coating gap,
The base material support device is
A first support member that abuts and supports the lower surface of the base material and a second support member that abuts and supports the lower surface of the base material are provided.
In the double-sided coating method, the base material is supported from a specific position near the second die head, and the first support member that has moved to the downstream side together with the base material is separated from the base material. The second support member is brought into contact with the lower surface of the base material at the specific position, and the second support member is moved toward the downstream side while supporting the base material on the lower surface of the base material. The first support member, which has been coated with the coating liquid by the second die head and has moved downstream together with the base material at the timing when the coating by the second die head reaches the end of the lower surface coating portion, is subjected to the first support member. A double-sided coating method in which the height exceeds the transfer height of the base material. Apply the coating liquid to the upper surface of the base material with the first die head,
The coating liquid is applied to the lower surface of the base material by the second die head, and the coating liquid is applied.
It is a double-sided coating method for drying the base material on which the coating liquid is applied to the upper surface and the lower surface.
The second die head is disposed downstream of, the substrate supporting device for supporting in contact with the lower surface of the substrate, to set the gap between the lower surface of the substrate and the second die head to the target coating gap,
The base material support device is
A first support member that abuts and supports the lower surface of the base material and a second support member that abuts and supports the lower surface of the base material are provided.
In the double-sided coating method, the base material is supported from a specific position near the second die head, and the first support member that has moved to the downstream side together with the base material is separated from the base material. The second support member is brought into contact with the lower surface of the base material at the specific position, and the second support member is moved toward the downstream side while supporting the base material on the lower surface of the base material. The coating liquid is applied by the second die head, and the coating liquid is moved to the downstream side together with the base material during the period from the start of coating of the lower surface coating portion by the second die head to the end of the lower surface coating portion. A double-sided coating method in which the first support member has been raised to a height exceeding the transfer height of the base material. The support member of the base material support device abuts on the lower surface uncoated portion formed between the lower surface coated portions of the base material to support the base material.
The double-sided coating method according to claim 1 or 2. Apply the coating liquid to the upper surface of the base material with the first die head,
The coating liquid is applied to the lower surface of the base material by the second die head, and the coating liquid is applied.
A double side coating device coating solution drying the substrate that has been coated on upper and lower surfaces,
The second die head is disposed downstream of, comprising a contact base for supporting the base material supporting device on the lower surface of the substrate,
The base material support device is
The base material is moved downstream together with the base material so that the gap between the second die head and the lower surface of the base material becomes the target coating gap, and the base material is raised to a height exceeding the transfer height of the base material. Double-sided coating equipment that can be used.

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