JP6742856B2 - Coating equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating apparatus for coating a coating liquid on one side or both sides of a base material sheet conveyed in the length direction.

A coated sheet in which a coating layer is formed on one side or both sides of a base sheet is used in various industrial fields. For example, in a secondary battery, a coating sheet formed by using a copper foil, an aluminum foil or the like as a base material sheet and forming a coating layer made of an electrode material such as graphite or cobalt on both surfaces of the base material sheet. It is used.

This type of coating sheet is a belt-shaped base material sheet that is continuously conveyed in the lengthwise direction, and a coating liquid is applied to one surface of the base material sheet by a coating device provided in the middle of the conveyance path. It is manufactured by a procedure of solidifying and fixing the coating solution through a drying step, and cut into an appropriate length for use. The coating device includes a coating die that is arranged to face the conveyance path of the base sheet. The coating liquid is discharged from the nozzle opening of the coating die, and is applied to one surface of the base material sheet which is in close proximity to the nozzle opening.

In this coating apparatus, it is important to equalize the coating thickness of the coating liquid, and this equalization keeps the facing distance between the nozzle opening of the coating die and one surface of the base sheet constant. It can be realized. Therefore, a backup roll that rolls on the other surface of the base material sheet being conveyed and is driven to rotate is provided, and the coating die is positioned with respect to the base material sheet supported by the backup roll so that the opposing distance between the two is constant. I try to keep it.

However, in a double-sided coating device that coats both the front and back sides of the base sheet, the back surface coating performed after the front surface coating cannot transfer the backup roll to the coated surface, There is no choice but to carry out without support of the base sheet by the backup roll. In this case, the coating die is positioned with respect to the conveyance path of the base material sheet, but the base material sheet being conveyed is unavoidably displaced with respect to the conveyance path due to fluttering, slack, etc. Since the facing distance between the sheet and the coating die varies, it is difficult to achieve a uniform coating thickness.

The double-sided coating (coating) apparatus disclosed in Patent Document 1 arranges a pinch roller on the downstream side of a coating die that coats the back surface, and uses the pinch roller to remove the edge portions on both sides in the width direction of the base sheet. It is configured to suppress the displacement of the base sheet by gripping each, and it is said that this configuration enables double-sided coating with a uniform coating thickness.

JP, 2016-7599, A

However, in the double-sided coating device disclosed in Patent Document 1, since both end edges of the base sheet are locally gripped by the pinch rolls, defects such as cuts and wrinkles in the base sheet occur at this gripping position. There is a problem that it will occur. In addition, the base sheet may be bent in the width direction between the positions gripped by the pinch rolls, resulting in an uneven distribution of the coating thickness in the width direction.

Furthermore, since the gripping position by the pinch roll is limited to the non-coated parts on both the front and back sides, for example, when the entire width of the base material sheet is the coated part, there is a non-coated part common to the front surface and the back surface. If you don't, you can't handle it.

The above problems are not limited to double-sided coating, and for example, in the case of single-sided coating using a mesh-shaped base sheet having a large number of through holes, the opposite side of the coated surface cannot be supported by a backup roll. The same happens in the case.

The present invention has been made in view of the above circumstances, and coating one surface of a base material sheet with a uniform coating thickness does not cause defects in the base material sheet, and the coating method is not limited. An object of the present invention is to provide a coating device that can be stably applied regardless of the above.

A coating apparatus according to an embodiment of the present disclosure includes a coating die that is arranged to face one surface of a strip-shaped base material sheet that is conveyed in the length direction, and a coating die that is discharged from a nozzle opening of the coating die. In a coating device that coats a liquid on one surface of the base sheet, the entire surface of the base sheet is rolled on the one surface of the base sheet on the upstream side in the transport direction with respect to the coating die, and the position in the transport direction is adjusted. A possible adjusting roll, a tension detector that detects the tension on both sides of the base sheet in the width direction, and a position change in the thickness direction of both side edges of the base sheet in the width direction, the direction of conveyance rather than the coating die. Position detector to detect on the downstream side, the tension difference between the width direction both sides of the base sheet by using the tension detection value by the tension detector Both sides of the base sheet by using the position detection value by the position detector The slack of the edges is calculated respectively, and when the slack is generated, the side where the slack is generated is moved in the upstream direction, and when the slack is not generated , the position of the adjusting roll is moved so that the side with a large tension is moved in the downstream direction. adjust, and a control unit which operates to eliminate the pre-SL was Rumi and before Sulfur butterfly force difference.

Adjusting rolls, rolling in contact with one surface of the base sheet at the upstream side of the coating die, Ru is the position adjustment by the operation of the control unit. The control unit calculates the slack on both side edges of the base sheet and the tension difference on both sides in the width direction, respectively, and when slack is generated, when the slack is not generated so as to move the generated side in the upstream direction. , Adjust the position of the adjusting roll so that the side with the higher tension moves in the downstream direction. The base sheet is pulled to the upstream side on the side with slack, and is loosened on the side with large tension, has no slack, and is placed at the position where the coating die is placed while maintaining tension balance in the width direction. to reach. Therefore, the position variation of the base sheet due to the slack and the difference in tension is suppressed at the arrangement position of the coating die , and the coating by the coating die is kept constant with the facing distance between the nozzle opening and the coating surface. It can be carried out and can form a coating layer having a uniform coating thickness. The adjusting roll is in rolling contact with one surface of the base material sheet before coating over the entire width, does not cause defects such as cuts and wrinkles in the base material sheet, and does not affect the coating layer. ..

The nozzle opening of the coating die, the a base sheet slit-shaped opening formed between the front lip and rear lip conveying direction arranged in direction of the rear lip located on the upstream side, a downstream side It is closer to one surface of the base sheet than the front lip located.

The rear lip closely facing one surface of the base material sheet is located on the upstream side in the transport direction, and prevents the coating liquid discharged from the nozzle port from leaking to the upstream side in the transport direction, and the downstream in the transport direction. Since it has the effect of improving the flow of the coating liquid to the side, it is possible to form a coating layer having a uniform thickness distribution in the length direction.

In the embodiment of the present disclosure, it is possible to cause no defects in the base sheet and to perform coating with a uniform coating thickness on one surface of the base sheet regardless of the coating form. it can.

It is a perspective view showing a schematic structure of a coating device concerning an embodiment. It is a perspective view which shows the structure of a back surface coating die. It is explanatory drawing of the coating state by a back surface coating die. 6 is a flowchart showing a procedure of a position adjusting operation by a control unit. It is explanatory drawing of the verification test implemented with the coating device which concerns on embodiment. It is a chart which shows the result of a verification test.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a perspective view showing a schematic configuration of a coating apparatus according to an embodiment. The illustrated coating apparatus is a double-sided coating apparatus that applies a coating treatment to both sides of a base material sheet 1 in the form of a strip that is continuously conveyed in the length direction, and includes a front surface coating die 2, a back surface coating die 3, and a backup The roll 4 and the adjusting roll 5 are provided.

The base material sheet 1 is, for example, a metal foil such as a copper foil or an aluminum foil, and the coating device applies an electrode material such as graphite or cobalt to both surfaces of the base material sheet 1 for a secondary battery. Used to manufacture coated sheets of.

The backup roll 4 is a large-diameter cylindrical roll supported rotatably around a substantially horizontal axis. The adjusting roll 5 is a small-diameter cylindrical roll, is rotatably supported by the rocking base 50, and is arranged diagonally above the backup roll 4. The rocking table 50 is fixed to the output end of an adjusting mechanism 51 that uses a motor or the like as a drive source, and rocks in a horizontal plane by the operation of the adjusting mechanism 51. The adjusting roll 5 swings together with the base 50, and a position adjusting operation is possible in which both sides in the length direction are moved in opposite directions in a horizontal plane from a reference position parallel to the backup roll 4.

The base material sheet 1 is pulled out from a holding roll (not shown), is wrapped around a part of the outer peripheral surface of the backup roll 4 to change its direction, as indicated by a two-dot chain line in FIG. Is wound around the outer peripheral surface of the upper part of the adjusting roll 5 and is directed in a substantially horizontal direction, and is set so as to be introduced into the drying device 6 which is partially shown in the drawing through the introducing port 60. The base material sheet 1 set in this way is fed with a feed force by the rotation of a feed roller (not shown) arranged on the outlet side of the drying device 6, and guided by the backup roll 4 and the adjusting roll 5, It is continuously conveyed in the direction shown by the blank arrow in FIG.

The surface coating die 2 is arranged so as to face the base material sheet 1 wound around the backup roll 4 from the surface (front surface) opposite to the surface wound around the backup roll 4. Further, the back surface coating die 3 is arranged on the downstream side of the adjusting roll 5 so as to face the surface (rear surface) on the same side as the winding surface around the adjusting roll 5.

FIG. 2 is a perspective view schematically showing the structure of the back surface coating die 3. As shown in the figure, the back surface coating die 3 is provided with a rectangular parallelepiped main body portion 3a that is long in one direction, and a nozzle portion 31 that is connected to one side surface of the main body portion 3a over the entire length. A hollow liquid chamber 30 extending in the longitudinal direction is formed inside the main body 3a. The liquid chamber 30 is connected to a coating liquid supply source (not shown) provided outside. The nozzle portion 3b has a shape that narrows in a taper shape with increasing distance from the main body portion 3a. Two slit-shaped nozzle openings 31 extending in the longitudinal direction are juxtaposed on the tip surface of the nozzle portion 3b, and these nozzle openings 31 are provided on the main body portion 3a via separate communication passages. It communicates with the chamber 30.

The back surface coating die 3 configured as described above serves to discharge the coating liquid fed from the liquid supply source into the liquid chamber 30 through the nozzle port 31. The nozzle opening 31 is closely opposed to the back surface of the base material sheet 1 delivered to the downstream side of the adjusting roll 5 from a lower position, and the coating liquid discharged from the nozzle opening 31 is delivered to the downstream side of the adjusting roll 5. Is applied to the back surface of the base material sheet 1.

FIG. 3 is an explanatory diagram of a coating state by the back surface coating die 3. The outline arrows in the figure indicate the conveyance direction of the base sheet 1 to be coated. The nozzle opening 31 of the back surface coating die 3 is formed as a gap between the front lip 31a on the downstream side in the transport direction and the rear lip 31b on the upstream side in the transport direction.

Here, the rear lip 31b is made higher than the front lip 31a, and a dimensional difference indicated by δ in the figure is set between them. Further, the nozzle port 31 of the back surface coating die 3 may be opposed to the back surface of the base material sheet 1 so that the discharge direction of the coating liquid becomes vertical as shown in FIG. Alternatively, they may face each other with a slight inclination (about 2° to 3°) toward the upstream side.

The coating liquid discharged from the nozzle opening 31 is applied to the lower surface (back surface) of the base material sheet 1 conveyed along the upper side of the nozzle opening 31 to form the coating layer 10. As described above, the rear lip 31b forming the nozzle opening 31 is higher than the front lip 31a, and the rear lip 31b is located closer to the base sheet 1 than the front lip 31a. It is possible to prevent the coating liquid discharged from the substrate from leaking to the upstream side and improve the flow of the coating liquid to the downstream side. The dimensional difference δ between the front lip 31a and the rear lip 31b is set according to the thickness of the coating layer 10, for example, about ½ of the thickness of the coating layer 10.

With the configuration and arrangement of the nozzle openings 31 as described above, in continuous coating, the coating layer 10 having a uniform thickness distribution in the length direction can be formed, and further, the missing portion can be formed at each appropriate length. In the intermittent coating in which the gap is formed, it is possible to suppress the defective shape of the coating layer 10 that occurs at the start end and the end of the cutout portion.

The thickness of the coating layer 10 can be adjusted by changing the facing distance between the lower surface of the base material sheet 1 and the nozzle openings 31. This adjustment can be realized, for example, by moving the adjusting roll 5 in the vertical direction. Further, the vertical movement of the adjusting roll 5 can be performed independently on both sides of the adjusting roll 5 in the length direction (width direction of the base sheet 1), so that the coating in the width direction of the base sheet 1 can be performed. It can also be used for adjusting the thickness distribution of the work layer 10.

The front surface coating die 2 has the same configuration as the back surface coating die 3. The nozzle opening of the surface coating die 2 is opposed to the surface of the base material sheet 1 wound around the backup roll 4, and the surface of the base material sheet 1 is discharged from the nozzle opening of the surface coating die 2. The coating layer 10 is similarly formed by the coating liquid. The front surface coating die 2 has two nozzle openings similarly to the back surface coating die 3, and on the surface of the substrate sheet 1, on the downstream side of the facing position of the front surface coating die 2, as shown in FIG. As shown, two coating layers 10 arranged in the width direction are formed.

The base material sheet 1 having the coating layer 10 formed on the front surface changes its direction after passing through the adjusting roll 5 that rolls over the entire width of the back surface, is conveyed in the horizontal direction, and passes through the opposite position of the back surface coating die 3. On the back surface of the base material sheet 1, two coating layers 10 aligned with the coating layer 10 on the front surface side are similarly formed on the downstream side of the facing position of the back surface coating die 3. A known position deviation correcting device that corrects the position deviation of the base sheet 1 in the width direction is provided on the upstream side of the backup roll 4, and the formation position of the front and back coating layers 10 is adjusted by this adjusting mechanism. Can be matched by the operation of.

The substrate sheet 1 having the coating layers 10 formed on both front and back sides in this manner is fed into the drying device 6 through the inlet 60. The coating layer 10 is solidified and fixed while passing through the inside of the drying device 6, and a coated sheet including the solidified coating layer 10 on both surfaces of the base material sheet 1 is manufactured.

In the operation of the coating apparatus as described above, the coating by the surface coating die 2 is carried out by supporting the base material sheet 1 from the back side by the backup roll 4, so that the nozzle opening of the surface coating die 2 and the base material are The facing interval with the surface of the sheet 1 can be kept constant, and a uniform coating thickness can be realized in the length direction and the width direction.

On the other hand, the coating with the back side coating die 3 is carried out without support by the backup roll 4, but the substrate sheet 1 which is being conveyed and faces the nozzle opening 31 of the back side coating die 3 is flapping, sagging or the like. Since the displacement is unavoidable with respect to the transport path, the facing distance between the nozzle opening 31 of the back surface coating die 3 and the back surface of the base material sheet 1 varies.

The adjustment roll 5 arranged on the upstream side of the back surface coating die 3 suppresses the displacement of the base material sheet 1 at the position facing the back surface coating die 3, and the nozzle opening 31 of the back surface coating die 3 and the base material sheet. It is provided in order to keep the facing distance from the back surface of 1 as constant as possible. As described above, the adjusting roll 5 swings in the horizontal plane together with the base 50 by the operation of the adjusting mechanism 51. By this swinging, the position of the adjusting roll 5 is adjusted such that when one side in the length direction moves to the upstream side in the transport direction of the base sheet 1, the other side moves to the downstream side in the transport direction.

As shown in FIG. 1, the operation command of the control unit 7 is given to the adjustment mechanism 51, and the adjustment mechanism 51 operates according to the operation command from the control unit 7. The control unit 7 includes a CPU, a ROM, and a RAM, and adjusts the position of the adjusting roll 5 by the operation of the CPU according to the control program stored in the ROM.

The controller 7 is supplied with the tension detection value by the tension detector 70 and the position detection value by the position detector 71, respectively. The tension detector 70 is a detector that detects tension on both sides in the width direction of the base material sheet 1 fed from the adjusting roll 5 to the drying device 6, and, for example, by a load cell incorporated in the base 50, The supporting reaction force applied to the supporting portions on both sides can be detected. The position detector 71 is a detector that detects the vertical position of both side edges of the base sheet 1 in the width direction on the downstream side of the back surface coating die 3, and, for example, laser light is applied to both side edges of the base sheet 1 from above. It is possible to use a laser displacement meter that irradiates a laser beam and detects a relative position change of both side edges.

FIG. 4 is a flowchart showing the procedure of the position adjusting operation by the control unit 7. The control unit 7 starts its operation when the coating device starts to operate, takes in the tension detection value by the tension detector 70 and the position detection value by the position detector 71 (step S1), and uses the tension detection value to the substrate sheet. The tension difference on both sides in the width direction of 1 is calculated, and the amount of partial slack is calculated using the position detection value (step S2). The amount of slack on one side is the amount of slack generated on the side edge of the base material sheet 1, and includes which side as the deviation between the positions of the both side edges detected by the position detector 71. Is calculated.

Next, the control unit 7 determines whether or not there is slack (step S3). When it is determined that there is slack (step S3: YES), the position of the adjusting roll 5 is set such that the side with the slack is the base sheet 1 It is adjusted so as to move to the upstream side in the conveyance direction (step S4). In step S3, for example, it is determined that there is slack when the amount of slack calculated in step S2 exceeds a predetermined threshold value. The adjustment in step S4 may be performed, for example, so as to obtain a predetermined movement amount, or may be performed so as to obtain a movement amount corresponding to the amount of one-sided slack.

By the above operation, when one-sided slack is generated in the base material sheet 1, the position adjustment of the adjusting roll 5 is performed, and the side where the slackness is generated is pulled to the upstream side, and the one-sided slack state is eliminated. You can As a result, it is possible to suppress the positional variation of the base material sheet 1 facing the nozzle opening 31 of the back surface coating die 3 and keep the facing distance between the two constant.

The position detector 71 used for calculating the amount of one-sided slack may be arranged at an appropriate position between the back surface coating die 3 and the inlet 60 of the drying device 6, but the slack of the base sheet 1 It is desirable to dispose it near the large inlet 60.

On the other hand, when it is determined in step S3 that there is no slack (step S3: NO), the control unit 7 determines whether there is a tension difference (step S5), and when it is determined that there is a tension difference (step S5: YES). ), and the position of the adjusting roll 5 is adjusted so that the side with a large tension moves to the downstream side in the transport direction of the base material sheet 1 (step S6). In step S5, for example, it is determined whether the tension difference calculated in step S2 is a significant difference. The adjustment in step S6 may be performed, for example, so as to obtain a predetermined movement amount, or may be performed so as to obtain a movement amount corresponding to the tension difference.

By the above operation, when there is a significant difference in tension on both sides in the width direction of the base material sheet 1, the position adjustment of the adjusting roll 5 is performed as described above, the side with a large tension is loosened, and the side with a small tension is pulled in reverse, and The tension of the material sheet 1 can be made uniform over the entire width. As a result, at the position where the back surface coating die 3 is disposed, it is possible to suppress the positional variation of the base material sheet 1 due to the difference in tension, and to keep the facing distance between the back surface coating die 3 and the nozzle opening 31 constant. ..

After the position adjustment in step S4 or step S6, when it is determined that there is no tension difference in step S5 (step S5: NO), the control unit 7 determines whether the operation is completed (step S7). The operation of steps S1 to S6 is continued until it is determined that the operation is completed (step S7: YES).

As described above, the coating apparatus according to the embodiment includes the adjusting roll 5 arranged on the upstream side of the back surface coating die 3, and the adjusting roll 5 is formed on both side edges of the base sheet 1. , And the position adjustment is performed according to the tension difference on both sides in the width direction of the base material sheet 1, so that the coating by the back surface coating die 3 at a position without the support by the backup roll 4 is made to face the nozzle opening 31 and the coating surface. It can be carried out while keeping the distance constant, and the coating layer 10 having a uniform coating thickness in the length direction and the width direction can be formed.

The adjusting roll 5 rolls over the entire width of the base sheet 1, and the base sheet 1 is conveyed without causing defects such as cuts and wrinkles, so that the coating by the back surface coating die 3 can be stably performed. Can be done. Moreover, since the adjusting roll 5 is in contact with the back surface of the base material sheet 1 before coating, there is no risk of affecting the coating layers 10 on both front and back surfaces. Further, since the back surface coating die 3 has the above-described configuration and arrangement and enables stable delivery of the coating liquid from the nozzle port 31, this also realizes uniform coating thickness. It

The base sheet 1 may be displaced in the width direction by performing the position adjustment of the adjusting roll 5 described above. It can be solved by providing it.

FIG. 5 is an explanatory diagram of a verification test carried out by the coating apparatus according to the embodiment, and FIG. 6 is a table showing the results of the verification test. In this verification test, two coating layers 10a and 10b are formed on both surfaces of a base material sheet 1 made of PET (polyethylene terephthalate) as shown in FIG. 5, and each of these coating layers 10a and 10b is As indicated by the circles in FIG. 5, the base sheet 1 was cut out at four locations in the width direction and nine locations in the length direction (only three locations are shown), and a total of 72 circular sample pieces 11 with a diameter of 20 mm were obtained. Then, the procedure of verifying the uniformity of the coating layers 10a and 10b by measuring the weight of these sample pieces 11 was performed.

In FIG. 6, the weights of 72 sample pieces 11 are shown together with their respective sample positions. As shown in the figure, the weight of the sample piece 11 is between the maximum value of 110.1 g and the minimum value of 107.6 g, and the difference between the coating layers 10a and 10b is small. Except for the six sample pieces 11 shown by shading, they are within an error range of ±1% with respect to the average value of 108.9 g. From the results of the above verification test, it was confirmed that the coating layers 10a and 10b have good uniformity inside each other and between them.

The above embodiment has been described as an example of application to a double-sided coating device in which both sides of a base material sheet are coated, but the configuration of the embodiment is, for example, a mesh-shaped base having a large number of through holes. The present invention can be applied to a case where a back-up roll cannot support the opposite side of a coated surface, such as a single-sided coating device for coating a material sheet, and the same effect can be obtained.

It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above meaning but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 Base Material Sheet 2 Front Coating Die 3 Back Coating Die 5 Adjusting Roll 7 Control Unit 31 Nozzle Port 31a Front Lip 31b Rear Lip 70 Tension Detector 71 Position Detector

Claims (2)

A coating die provided with a coating die arranged to face one surface of a strip-shaped base material sheet conveyed in the length direction, and coating the coating liquid discharged from the nozzle opening of the coating die on the one surface of the base material sheet. In engineering equipment,
An adjusting roll that rolls over one surface of the base material sheet on the upstream side in the transport direction with respect to the coating die over the entire width, and is capable of position adjustment in the transport direction.
A tension detector that detects tension on both sides in the width direction of the base sheet,
A position detector that detects a position change in the thickness direction of both side edges in the width direction of the base sheet, on the downstream side in the transport direction with respect to the coating die ,
Using the tension detection value by the tension detector, the tension difference between the widthwise sides of the base sheet is calculated by using the position detection value by the position detector to calculate the slack of both side edges of the base sheet, respectively.
If the slack is caused to move the side occurs in the upstream direction, if the slack is not generated, by adjusting the position of said adjustment roll so as to move the tension larger side in the downstream direction, but before the SL Rumi and coating apparatus, characterized in that it comprises a control unit which operates to eliminate the pre-Sulfur butterfly force difference. The nozzle opening of the coating die is a slit-like opening formed between the front lip and rear lip arranged in the transport Direction of the base sheet, the rear lip located on the upstream side, located on the downstream side the front coating apparatus of claim 1, also are brought close to one surface of the base sheet than lip.

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