JP2018008218A - Intermittent coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermittent coating device enabling intermittent coating with good quality by preventing occurrence of coating defect resulting from droplets remaining on the discharge port of a coating die when shifting to a non-coating state.SOLUTION: An intermittent coating device comprises: a coating die 2 disposed facing a coating face; a liquid supply source 3 supplying a coating liquid 6; and a change-over valve 4 for selectively changing over the supply destination of the coating liquid 6 from the supply source 3 between a path 33 for supplying to the die 2 and the path 34 for returning to the source 3. The change-over valve 4 is equipped with: a housing 40 comprising a delivery chamber continuing in a delivery path 33, a reflux chamber continuing in the returning path 34 and an introduction chamber communicating with the delivery and reflux chambers and introducing the coating liquid from the supply source; and the shuttles 41 which are disposed at the communicating portions between the introduction chamber, and the delivery and reflux chambers, reciprocate between the end-opening and end-closing positions in order to open or close each communication portion, and have the portions entering into and going out from the delivery or reflux chamber while keeping the closing state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intermittent coating apparatus for intermittently coating a coating surface with a coating liquid.

  A coating sheet in which a coating layer is formed on one side or both sides of a base sheet is used in various industrial fields. This type of coating sheet transports a belt-shaped base sheet in the length direction, and coats the coating liquid on one surface (coating surface) of this base sheet with a coating device provided in the middle of the transport path. Then, it is manufactured by a procedure for solidifying and fixing the coating liquid through a subsequent drying step, and is used after being cut into an appropriate length.

  The coating apparatus includes a coating die that is disposed to face the conveyance path of the base sheet, and a liquid supply source that feeds the coating liquid to the coating die. The coating die has a slit-like discharge port that is close to and opposite to the coating surface, and the coating liquid fed from the liquid supply source is discharged from the discharge port of the coating die, and the coating surface of the base sheet Painted on.

  Patent Document 1 discloses a switching valve that switches a coating liquid supply destination between a supply source and a coating die between a supply path to the coating die and a return path to the supply source. There is disclosed an intermittent coating apparatus that includes a valve) and that enables intermittent coating by the operation of the switching valve. The switching valve includes a first valve body that opens and closes a supply path to the coating die, and a second valve body that opens and closes a return path to the liquid supply source. While the valve body is opened and the second valve body is closed, at the time of non-coating, intermittent coating is realized by closing the first valve body and opening the second valve body .

JP2015-112520A

  However, in the intermittent coating apparatus described in Patent Document 1, when the feeding of the coating liquid to the coating die is stopped for the transition from the coating state to the non-coating state, the coating before the stop is performed. There is a possibility that the liquid may remain in the form of droplets outside the opening of the discharge port.

  The liquid droplets remaining at the discharge port come into contact with the non-coated part of the base sheet, resulting in an incomplete coated part with stagnation, and the coating liquid for the transition to the next coated state. When the feeding is resumed, it is applied to the base sheet together with the newly fed coating liquid, and a coating failure such as the formation of a raised part with a large coating thickness at the beginning of the coating part. Cause it to occur.

  In Patent Document 1, the larger the gap between the discharge port and the coating surface, the slower the opening speed of the first valve body at the start of coating, thereby preventing the formation of the raised portion. However, it is difficult to effectively prevent the formation of the swelled portion, rather than a technique that focuses on the presence of the droplets.

  The present invention has been made in view of such circumstances, and prevents the occurrence of coating defects due to droplets remaining in the discharge port of the coating die when shifting to a non-coating state, with good quality. An object of the present invention is to provide an intermittent coating apparatus that enables intermittent coating.

  An intermittent coating apparatus according to an embodiment of the present disclosure includes a coating die disposed opposite to a coating surface, a liquid supply source that supplies a coating liquid, and a supply of the coating liquid from the liquid supply source. In the intermittent coating apparatus including a switching valve that selectively switches a tip between a delivery path to the coating die and a return path to the liquid supply source, the switching valve is a delivery chamber that is continuous with the delivery path. A housing having a return chamber connected to the return path, an introduction chamber that communicates with the delivery chamber and the return chamber and into which a coating liquid is introduced from the liquid supply source, the delivery chamber, the return chamber, and the introduction chamber; And a shuttle that reciprocates between the open end position and the closed end position to open and close each communication part, and the shuttle moves from the closed end position to the open end position. It has a portion that sometimes appears and disappears in the delivery chamber or the reflux chamber while keeping the closed state. .

  The shuttle on the delivery chamber side moves from the open end position to the closed end position and stops sending the coating liquid to the coating die when shifting to the non-coating state. The shuttle enters a closed state that interrupts the communication between the delivery chamber and the introduction chamber in the middle of movement, reaches the closed end position while keeping the closed state, and saturates in the delivery chamber, so that the coating liquid in the coating die is discharged. Pull back. Dispensing of the coating liquid from the coating die is stopped in a state of being drawn into the inner side of the discharge port, so that no liquid droplets remain outside the discharge port, and the liquid droplets come into contact with the coated surface during non-coating. And incomplete coating can be prevented beforehand. The shuttle on the reflux chamber side moves from the closed end position to the open end position to connect the reflux chamber to the introduction chamber. The coating liquid is returned from the reflux chamber to the liquid supply source, and circulates between the liquid supply source and the switching valve.

  The shuttle on the delivery chamber side moves from the closed end position to the open end position when coating is resumed. At this time, the shuttle protrudes into the delivery chamber while keeping the closed state, pushes the coating solution in the delivery chamber to the coating die, and draws the coating solution drawn into the inner side of the discharge port during non-coating at the opening end. Push back to. The coating liquid is discharged from the discharge port immediately after resuming delivery, and can start coating without delay, and there is no risk that the liquid droplets remaining outside the discharge port will form a bulge. Coating with good coating quality is possible.

  In addition, the shuttle is a cylindrical body formed with a concave groove extending in the axial length direction from one end portion on the outer periphery, and can move while maintaining a closed state with a seal ring that elastically contacts the non-formed area of the concave groove. It is as.

  The shuttle can appear and disappear in the range of the non-formation area of the concave groove elastically contacting the seal ring, and the drawing back and extrusion of the coating liquid can be reliably realized with a simple configuration.

  The coating die has a discharge port close to one surface of the belt-shaped base sheet conveyed in the length direction, and the coating liquid discharged from the discharge port by switching to the delivery path is the base. Apply to one side of the material sheet.

  The coating die applies the coating liquid discharged from the discharge port onto one surface of the belt-like substrate sheet conveyed in the length direction. On one surface of the substrate sheet, the coated portion and the non-coated portion can be formed with good quality by the operation of the switching valve.

  In the embodiment of the present disclosure, it is possible to prevent the occurrence of coating failure due to droplets remaining in the discharge port of the coating die at the time of transition to a non-coating state, and realize intermittent coating with good quality Can do.

It is a schematic diagram which shows schematic structure of the coating apparatus which concerns on embodiment. It is operation | movement explanatory drawing of a switching valve. It is operation | movement explanatory drawing of a switching valve. It is operation | movement explanatory drawing of a switching valve. It is explanatory drawing which shows the mode of coating.

  Embodiments of the present invention will be described below. Drawing 1 is a mimetic diagram showing the schematic structure of the coating device concerning an embodiment. As shown in the figure, the coating apparatus is configured to perform a coating process on one surface (coating surface) of the base sheet 1 having a belt shape conveyed in the length direction, and the coating die 2, the liquid supply source 3, and the switching. A valve 4 is provided.

  The base sheet 1 is, for example, a resin sheet such as PET (polyethylene terephthalate), or a metal foil such as copper foil or aluminum foil, and is guided by a pair of guide rolls 11 and 12 and a backup roll 10 between them. And conveyed in the direction indicated by the arrow in the figure.

  The guide rolls 11 and 12 and the backup roll 10 are cylindrical rolls supported so as to be rotatable around axes parallel to each other, and the base sheet 1 is wound around the outer periphery of the backup roll 10 with the coating surface facing outward. It is hung.

  The coating die 2 is disposed so as to face the coating surface of the base sheet 1 wound around the backup roll 10, communicates with the liquid reservoir 20 and the liquid reservoir 20, and has a slit shape close to and opposed to the coating surface. The discharge port 21 is provided.

  The liquid supply source 3 includes a coating liquid tank 30 and a metering pump 31. A coating liquid 6 to be applied to the base sheet 1 is stored inside the coating liquid tank 30. The metering pump 31 is provided in the middle of the liquid feed pipe 32 having one end connected to the bottom of the coating liquid tank 30. The other end of the liquid feeding pipe 32 is connected to the switching valve 4, and the coating liquid 6 in the coating liquid tank 30 is sent to the switching valve 4 through the liquid feeding pipe 32 by the operation of the metering pump 31. .

  The switching valve 4 includes a housing 40 and two shuttles 41 and 41 that reciprocate inside the housing 40. 2-4 is explanatory drawing of operation | movement of the switching valve 4, and the structure of the principal part of the switching valve 4 is shown schematically. As shown in these drawings, an introduction chamber 40a, a delivery chamber 40b, and a reflux chamber 40c are provided inside the housing 40. One side of the introduction chamber 40a is connected to the liquid feeding pipe 32, and the coating liquid 6 fed through the liquid feeding pipe 32 is introduced into the introduction chamber 40a.

  The delivery chamber 40b and the reflux chamber 40c are chambers having a circular cross section that respectively communicate with the other side of the introduction chamber 40a, and are arranged in parallel with the axial length direction being parallel. The delivery chamber 40 b is connected to the liquid reservoir 20 of the coating die 2 by a delivery path 33, and the reflux chamber 40 c is connected to the coating liquid tank 30 of the liquid supply source 3 by a return path 34.

  Both the shuttles 41 and 41 have a cylindrical shape, and are supported by the respective support shafts 42 and 42 so as to be coaxial with the communicating portion of the delivery chamber 40b and the reflux chamber 40c with the introduction chamber 40a. The support shafts 42 and 42 are extended to the outside of the housing 40 and are connected to separate drive devices 43 and 43 (see FIG. 1). The drive devices 43 and 43 include, for example, a motor as a drive source and a transmission mechanism that converts the rotation of the motor into a linear motion and transmits the linear motion to the support shafts 42 and 42. It moves in the axial length direction (direction indicated by an arrow in the figure) in accordance with the operation of the drive devices 43, 43 transmitted through the 42, 42.

  Seal rings 44, 44 projecting inward are provided on the inner peripheral surfaces of the delivery chamber 40 b and the reflux chamber 40 c, and these seal rings 44, 44 are elastically contacted with the outer periphery of the shuttles 41, 41. It is. On the outer periphery of the shuttles 41, 41, a plurality of concave grooves 45 extending in the circumferential direction from one end portion are provided in parallel in the circumferential direction.

  FIG. 2 shows the shuttles 41 and 41 in the initial position. At this time, the seal rings 44, 44 are in elastic contact with the respective shuttles 41, 41 at the end portions of the areas where the concave grooves 45 are formed, and the delivery chamber 40b and the reflux chamber 40c are connected to the seal rings 44, 44 and the shuttle 41, 41 is in a state where communication with the introduction chamber 40a is blocked.

  The shuttles 41 and 41 move in opposite directions from the initial position shown in FIG. FIG. 3 shows a state where the shuttle 41 on the delivery chamber 40b side moves upward to reach the open end position, and the shuttle 41 on the reflux chamber 40c side moves downward to reach the closed end position (delivery state). On the contrary, in FIG. 4, the shuttle 41 on the delivery chamber 40b side moves downward to reach the closed end position, and the shuttle 41 on the reflux chamber 40c side moves upward to reach the open end position (return). State) is shown.

  In the delivery state shown in FIG. 3, the shuttle 41 on the delivery chamber 40 b side is in elastic contact with the seal ring 44 in the middle of the formation area of the plurality of concave grooves 45, and each concave groove 45 is an elastic contact portion of the seal ring 44. The delivery chamber 40b communicates with the introduction chamber 40a through the openings of the plurality of concave grooves 45.

  On the other hand, the shuttle 41 on the reflux chamber 40 c side is in elastic contact with the seal ring 44 in a region where the plurality of concave grooves 45 are not formed, and each concave groove 45 is located in the introduction chamber 40 a below the elastic contact portion of the seal ring 44. The reflux chamber 40c is in a closed state where communication with the introduction chamber 40a is blocked. Accordingly, the coating liquid introduced into the introduction chamber 40a is fed into the delivery chamber 40b and sent to the coating die 2 through the delivery path 33, as indicated by broken arrows in the drawing.

  In the return state shown in FIG. 4, the shuttle 41 on the reflux chamber 40 c side opens in contact with the seal ring 44 in the middle of the formation area of the concave groove 45, and the shuttle 41 on the delivery chamber 40 b side opens in the concave groove 45. The seal ring 44 is elastically contacted and closed in the non-forming region. Therefore, the reflux chamber 40c communicates with the introduction chamber 40a, the delivery chamber 40b maintains a non-communication state with the introduction chamber 40a, and the coating liquid introduced into the introduction chamber 40a is indicated by a broken arrow in the drawing. Then, it is fed into the reflux chamber 40 c and is returned to the coating liquid tank 30 of the liquid supply source 3 through the return path 34.

  The switching valve 4 operates so as to alternately realize the delivery state and the return state as described above, and the coating liquid 6 delivered from the liquid supply source 3 is delivered to the coating die 2 when switching to the delivery state. It is returned to the coating liquid tank 30 when switching to the return state.

  The coating liquid 6 delivered to the coating die 2 is discharged from the discharge port 21 through the liquid reservoir 20 and is applied to the coating surface of the base sheet 1 facing the discharge port 21. Is continuously performed while the switching valve 4 is in the delivery state, and is stopped by switching to the return state. Therefore, the base sheet 1 has a coating portion of the coating liquid 6 as shown in FIG. Non-coated portions are alternately formed, and intermittent coating is realized.

  FIG. 5 is an explanatory view showing the state of coating. FIG. 5A shows a state during coating, and the coating liquid 6 discharged from the discharge port 21 of the coating die 2 is conveyed in the direction indicated by the white arrow in the drawing. It is applied to the coated surface. Since the coating liquid 6 once stored in the liquid reservoir 20 is uniformly dispersed and sent out from the discharge port 21, it is possible to realize coating with an equal thickness.

  The coating thickness of the coating liquid 6 is determined by the conveyance speed of the base sheet 1 and the discharge amount of the coating liquid 6 from the discharge port 21, and the discharge amount of the shuttle 41 on the delivery chamber 40b side in the delivery state. Since it is determined by the moving position, a desired coating thickness can be realized by appropriately setting the moving position of the shuttle 41 according to the conveyance speed of the base sheet 1.

  FIG. 5B shows a state during non-coating. The coating of the coating liquid 6 is stopped by switching the switching valve 4 to the return state and stopping the feeding of the coating liquid 6 to the coating die 2 as described above. At this time, the shuttle 41 on the delivery chamber 40b side moves from the open end position shown in FIG. 3 to the closed end position shown in FIG. 4 through the initial position shown in FIG.

  The delivery of the coating liquid 6 is stopped when the communication between the delivery chamber 40b and the introduction chamber 40a is interrupted by reaching the initial position, but the shuttle 41 on the delivery chamber 40b side further descends after the stop. To reach the closed position. The internal volume of the delivery chamber 40b increases as the shuttle 41 descends, and the coating liquid 6 in the coating die 2 is drawn back to the delivery chamber 40b.

  Therefore, at the discharge port 21 of the coating die 2, as shown in FIG. 5B, the discharge is reliably stopped in a state where the coating liquid 6 is drawn inside the opening end, and is indicated by a broken line in the drawing. Thus, the droplet 6a adhering to the outside of the opening end does not remain. Accordingly, the base sheet 1 is formed with a coating portion of the coating liquid 6 having a substantially constant thickness up to the end (the lower end in the figure), and the droplets 6a remaining in the discharge ports 21 are formed on the base sheet. It is possible to eliminate the risk of contact with the non-coated portion of 1 and incomplete coating.

  On the other hand, when the switching valve 4 is switched to the return state, the shuttle 41 on the reflux chamber 40c side moves to the open end position shown in FIG. As a result, the reflux chamber 40c communicates with the introduction chamber 40a, and the coating liquid introduced into the introduction chamber 40a is returned to the liquid supply source 3 via the reflux chamber 40c and the return path 34, and the coating liquid being uncoated is applied. 6 circulates between the liquid supply source 3 and the switching valve 4. The internal pressure of the introduction chamber 40a can be maintained at a pressure equal to that during coating by appropriately setting the flow path resistance of the return path 34. The flow path resistance can be set, for example, by providing a throttle part in the middle of the return path 34 and changing the throttle opening of the throttle part.

  5C and 5D show a state at the time of resuming coating. Coating of the coating liquid 6 is resumed by switching the switching valve 4 to the sending state and sending the coating liquid 6 to the coating die 2 as described above. At this time, the shuttle 41 on the delivery chamber 40b side moves from the closed end position described above to the open end position through the initial position.

  The delivery of the coating liquid 6 is resumed when the shuttle 41 moves from the initial position to the open end position, and the delivery chamber 40b communicates with the introduction chamber 40a. It has moved to the position, and the non-formation area of the concave groove 45 of the shuttle 41 protrudes into the delivery chamber 40b. As a result, the coating liquid 6 in the delivery chamber 40 b is pushed out by the amount corresponding to the protrusion of the shuttle 41 and fed into the coating die 2.

  Accordingly, at the discharge port 21 of the coating die 2, as shown in FIG. 5C, the coating liquid 6 drawn inwardly during non-coating is pushed back to the open end, and the coating liquid 6 Is discharged from the discharge port 21 immediately after resuming delivery. Since the internal pressure of the introduction chamber 40a is kept substantially constant even during non-coating, a predetermined amount of the coating liquid 6 is discharged from the discharge port 21 immediately after the resumption of coating, and is applied to the coated surface of the base sheet 1. As shown in FIG. 5D, the coating liquid 6 is applied with an appropriate thickness from the starting end (the upper end in the figure).

  At this time, since there is no liquid droplet 6a left at the time of stopping the coating at the discharge port 21 of the coating die 2, at the start of the coating liquid 6 applied to the substrate sheet 1, The raised portion 6b indicated by a broken line in 5D is not formed.

  As described above, according to the coating apparatus of the embodiment, the above-described operation of the switching valve 4 can realize intermittent coating in which the coating liquid 6 is coated with a substantially uniform thickness from the start end to the end. it can. In addition, in embodiment, although the intermittent coating apparatus which makes the coating object one surface of the base material sheet 1 conveyed in the length direction was demonstrated, the structure of embodiment is the coating surface of the stationary target object In addition, the present invention can be applied to an intermittent coating apparatus in which coating is performed with a coating die that moves along the coating surface, and the same effect can be obtained.

  The shuttle 41 is not limited to the configuration shown in the embodiment, and has an appropriate configuration having a portion (a portion corresponding to a non-formation region of the concave groove 45) that appears and disappears in the delivery chamber 40b or the reflux chamber 40c while keeping the closed state. It can be.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Substrate sheet 2 Coating die 3 Supply source 4 Switching valve 6 Coating liquid 21 Discharge port 33 Delivery path 34 Return path 40 Housing 40a Introduction chamber 40b Delivery chamber 40c Reflux chamber 41 Shuttle 44 Seal ring 45 Groove

Claims (3)

A coating die disposed opposite to the coating surface, a liquid supply source for supplying the coating liquid, a delivery path for supplying the coating liquid from the liquid supply source to the coating die, and the liquid supply In the intermittent coating apparatus comprising a switching valve that selectively switches between the return path to the source,
The switching valve is
A housing including a delivery chamber connected to the delivery path, a reflux chamber linked to the return path, and an introduction chamber that communicates with the delivery chamber and the reflux chamber and into which the coating liquid is introduced from the supply source;
A shuttle that is arranged in each of the communicating portions of the delivery chamber and the reflux chamber and the introducing chamber, and reciprocates between an open end position and a closed end position to open and close each communicating portion;
The intermittent coating apparatus, wherein the shuttle has a portion that appears and disappears in the delivery chamber or the reflux chamber while keeping the closed state when moving from the closed end position to the open end position.   The shuttle is a cylindrical body in which a groove extending in the axial length direction from one end portion is formed on the outer periphery, and is movable while maintaining a closed state with a seal ring that elastically contacts a non-formed area of the groove. The intermittent coating apparatus according to claim 1.   The coating die has a discharge port close to one surface of a strip-shaped base sheet conveyed in the length direction, and the coating liquid discharged from the discharge port by switching to the delivery path is the base material The intermittent coating apparatus of Claim 1 or Claim 2 which coats on one surface of a sheet | seat.

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