JP2017156068A - Dyer and drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dryer capable of evenly drying a coating film without any distortion.SOLUTION: A dryer includes a nozzle configured to spray airflow to one surface of a sheet 1, and an air shield wall 4 positioned near end parts on both sides of the sheet and configured to reduce wraparound of airflow to an opposite surface of the sheet. Reducing wraparound is to reduce an air wraparound amount of airflow 2 so that wraparound air does not affect drying.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drying apparatus and a drying method.

  There is a technique in which a liquid coating film is formed on a sheet and dried to form a film. In order to obtain a uniform film by such a film formation technique, it is important to first form a coating film having a uniform thickness and simultaneously perform drying.

  A typical drying device is an air flow drying device. The airflow drying apparatus includes a device that blows airflow directly on a coating film and a device that blows airflow on the back surface where the coating film is not formed. Here, the former is called a surface airflow drying device, and the latter is called a backside airflow drying device.

  The surface airflow drying device has an advantage of high drying efficiency. On the other hand, there is a problem that only the surface of the coating film is dried and the surface film is not dried, and bubbles are likely to be generated due to rapid drying. A backside airflow dryer solves this problem. However, the backside airflow drying apparatus also has a problem that the airflow circulates from the edge of the sheet to the coating film forming surface, the edge is dried quickly, and the uniformity deteriorates.

  The technique of the drying apparatus which solves said problem is disclosed by patent document 1, for example. FIG. 10 is a cross-sectional view showing this drying apparatus. The drying apparatus has a blowing nozzle 104 that blows hot air 103 on the back surface of the sheet 102 on which the coating film 101 is formed. A partition plate 105 for limiting the airflow to a range narrower than the width of the sheet 102 and blowing it to the back surface of the sheet is provided at both ends of the blowing nozzle 104. In Patent Document 1, it is desirable that the range in which the hot air is blown is 80% or more and 100% or less of the width of the coating film, and is symmetric with respect to the center line of the sheet 102. By adopting the above-described configuration, there is no warm air flowing from the end of the sheet 102 to the coating film forming surface, so that the uniformity of drying of the coating film can be ensured.

JP 2014-56840 A

  However, the technique of Patent Document 1 has a problem that distortion occurs at the end of the coating film. In this technique, the portion of the sheet located within the hot air blowing range is heated, and the portion located outside the hot air blowing range is not heated. For this reason, a difference in the amount of expansion or contraction corresponding to the temperature difference occurs between the two parts. This difference causes distortion in the vicinity of the end portion of the coating film located at the boundary between the two. That is, the strain is fixed in the dried coating film.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drying apparatus that uniformly dries a coating film without distortion.

  In order to solve the above problems, a drying apparatus according to the present invention includes a nozzle that blows an airflow on one surface of a sheet, and a windshield that is located near the end of the sheet and reduces the wraparound of the airflow to the opposite surface of the sheet And a wall.

  The effect of the present invention is to provide a drying apparatus that uniformly dries the coating film without distortion.

It is sectional drawing which shows 1st Embodiment. 1 is a side view showing a first embodiment. It is sectional drawing which shows 2nd Embodiment. It is sectional drawing which shows a general drying apparatus. It is sectional drawing which shows 3rd Embodiment. It is sectional drawing which shows 4th Embodiment. It is sectional drawing which shows an example of 5th Embodiment. It is sectional drawing which shows another example of 5th Embodiment. It is sectional drawing which shows 6th Embodiment. It is a top view which shows the specific example of the windshield wall of 6th Embodiment. It is sectional drawing which shows the drying apparatus of patent document 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following. In addition, the same number is attached | subjected to the same component of each drawing, and description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a cross-sectional view showing the first embodiment. The drying device includes a blowout nozzle 3 that blows the airflow 2 on one surface of the sheet 1 and a wind shielding wall 4 that is located near both ends of the sheet 1 and reduces the wraparound of the airflow 2 to the opposite surface of the sheet 1. Have. Here, reducing the wraparound is to reduce the amount of sneak in the airflow 2 to such an extent that the circulated airflow does not affect the drying.

  FIG. 2 is a side view when the drying apparatus is viewed from the direction perpendicular to the sheet traveling direction 5, that is, the lateral direction when the sheet 1 travels in the direction perpendicular to the paper surface in the drying apparatus of FIG. The wind shielding wall 4 has a width that covers at least the air flow blowing range of the blowing nozzle 3. For example, the wind shielding wall 4 is made slightly larger than the blowing nozzle 3. 2 also illustrates the arrangement of the feed roll 6 and the take-up roll 7 when the roll-to-roll method is used.

  By setting it as said structure, an airflow can be reduced, blowing an airflow uniformly on one surface of a sheet | seat. For this reason, the drying apparatus which dries a sheet | seat uniformly without distortion can be provided.

(Second Embodiment)
FIG. 3 is a cross-sectional view showing the second embodiment. The drying device includes a blowing nozzle 30 that blows the airflow 20 on one side of the sheet 10 and a plate-shaped wind shielding wall 40 that extends in the direction opposite to the nozzle from the vicinity of the end of the sheet 10. A coating film 50 is formed on one side of the sheet 10. When the roll-to-roll method is used, the sheet 10 proceeds in a direction perpendicular to the paper surface. That is, in the case of the roll-to-roll method, FIG. 3 shows a cross-sectional view in the width direction of the sheet. Although not shown, the wind shielding wall 40 has a width that covers the air flow blowing range of the blowing nozzle 30 in the direction perpendicular to the paper surface.

  The drying device blows the coating film 50 by blowing the airflow 20 onto a surface (hereinafter also referred to as a back surface) opposite to a coating film forming surface (hereinafter also referred to as a surface). If the coating film 50 is, for example, a resin containing an organic solvent or a thermosetting resin, hot air having a temperature higher than room temperature can be used as the air flow 20. In such a case, the sheet 10 is heated by the hot air, the heat of the sheet 10 propagates to the coating film 50, and the coating film 50 is dried. However, in this embodiment, the temperature of the airflow 20 is arbitrary.

  Here, for comparison, drying using a drying apparatus without the wind shielding wall 40, that is, a general drying apparatus will be described. FIG. 4 is a cross-sectional view showing the above general drying apparatus. The drying device blows the airflow 20 blown from the blowout nozzle 30 onto the back surface of the sheet 10 on which the coating film 50 is formed. The air flow 20 wraps around the surface of the sheet 10 in the vicinity of the widthwise end of the sheet 10 as indicated by the arrow 20a in FIG. By the action of the airflow 20a that circulates in this way, the vicinity of the end portion in the width direction of the coating film 50 dries faster than the center portion in the width direction.

  On the other hand, in the drying apparatus of this embodiment shown in FIG. 3, most of the airflow blown to the widthwise end of the sheet 10 by the windbreak wall 40 is guided to the outside of the windshield wall 40, and the sheet of the airflow 20 10 The wraparound to the surface is suppressed. Therefore, the wind shielding wall 40 is disposed in the vicinity of the width direction end portion of the sheet 10 as long as it does not contact the sheet 10. Specifically, an interval of about 1 to 10 mm is formed between the sheet 10 and the wind shielding wall 40, for example. The reason for providing such an interval is to prevent the windshield wall 40 and the sheet 10 from contacting each other when the sheet 10 travels. Therefore, it may be adjusted according to the blur width of the sheet 10.

  With such an arrangement, a part of the airflow 20 passes through the gap between the sheet 10 and the wind shielding wall 40 to the surface side. In FIG. 2, this is indicated by a dotted arrow. However, the air volume of this air flow is greatly reduced as compared with the case where the wind shielding wall 40 is not provided. Moreover, the component which advances along the wind-shielding wall 40 also arises by the Coanda effect. As a result, excessive drying of the end portion of the coating film 50 due to the air current 20 wrapping around is suppressed, and uniformity is ensured. Further, since the airflow is uniformly blown over the entire sheet 10, the distortion as in Patent Document 1 does not occur in the coating film 50 after drying.

  As described above, according to the present embodiment, it is possible to configure a drying apparatus that uniformly dries the coating film without distortion.

(Third embodiment)
In the second embodiment, the wind shielding wall is formed in a shape extending from the vicinity of the end of the sheet to the side opposite to the blowing nozzle. However, the same effect can be obtained by extending in a different direction. FIG. 5 is a cross-sectional view showing an example of a drying apparatus that realizes this. In the example of FIG. 5, the wind shielding wall 41 has a shape extending from the vicinity of the end of the sheet 10 in a direction substantially parallel to the surface of the sheet 10.

  When the windshield wall 41 is in such a shape and arrangement, the majority of the airflow 20 blown to the end of the sheet 10 passes through the outer edge of the windshield wall 41 and wraps around the surface of the windshield wall 41. Proceed as you go. This state is indicated by an arrow 20b in FIG. In this case, as in a general drying apparatus, the airflow wraps around the surface side, but the distance from the end of the coating film 50 is not so great that the drying of the coating film 50 is not affected. Part of the airflow 20 passes through the gap between the sheet 10 and the wind shielding wall 41. In FIG. 5, this air flow is indicated by a dotted arrow. However, the airflow of the airflow is greatly reduced as compared with the case where the windshield wall 40 is not provided. Therefore, excessive drying of the end portion of the coating film 50 due to the wraparound of the airflow 20 can be suppressed.

  Next, a specific example of the size of the windshield wall will be described. For example, when the temperature of the airflow 20 is 80 ° C. and the wind speed is 25 m / s as drying conditions, the airflow 20 wraps around when the length of the windshield wall 41 extending in the outer direction of the sheet 10 is about 10 cm. The drying of the coating film 50 can be prevented from being affected. When the wind speed is smaller than this, the length of the wind shield wall 41 may be shorter, and when the wind speed is large, the length of the wind shield wall 41 may be adjusted to be longer. The distance between the sheet 10 and the wind shielding wall 41 is set so that the sheet 10 does not contact the wind shielding wall 41. Specifically, if the apparatus has normal accuracy, it can be set to about 1 to 10 mm. In the above description, the extending direction of the windshield wall is substantially parallel to the surface of the sheet, and in the second embodiment, substantially perpendicular to the surface of the sheet. However, the same effect can be obtained in other directions. Is possible.

  As described above, according to the present embodiment, a drying apparatus that uniformly dries the coating film without distortion can be configured as in the second embodiment.

(Fourth embodiment)
It is also possible to extend the windshield wall from the vicinity of the edge of the sheet on the blowing nozzle side in the outward direction of the sheet. An example is shown in FIG. The wind shielding wall 42 has a shape extending from the vicinity of the width direction end of the sheet 10 on the blowing nozzle 30 side in a direction away from the sheet 10. In this case, as in the example of FIG. 5, the airflow 20 heading toward the end in the width direction of the sheet 10 is mostly along the outside of the windbreak wall 42 as indicated by the arrow 20c, and the surface of the windbreak wall 42. Go around to the side. Since the airflow is separated from the end portion of the coating film 50 by the wind shielding wall 42, it does not contribute to drying of the end portion of the coating film 50. For this reason, the same effect as that of the third embodiment can be obtained. In the case of this example as well, a part of the airflow passes through the gap between the sheet 10 and the wind shielding wall 42 indicated by the dotted arrow in FIG. 6, but the air volume is greatly reduced. The effect on the drying of the parts is small.

  As described above, according to the present embodiment, a drying apparatus that uniformly dries the coating film without distortion can be configured as in the third embodiment.

(Fifth embodiment)
In the first to fourth embodiments, the example in which the windshield wall is a solid having no opening has been described, but the windshield wall may have an opening. FIG. 7 shows an example in which a windshield wall 43 having an opening is used as the windshield wall with the same configuration as the second embodiment. Other configurations are the same as those of the second embodiment. Even if the windshield wall 43 is a plate-like body having a plurality of through-holes as shown in FIG. 6, for example, the airflow 20 that wraps around the surface of the coating film 50 through the opening is very small. An effect is obtained.

  Moreover, it is possible to use the wind-shielding wall which has an opening part also in the structure of 3rd Embodiment. An example of such a configuration is shown in FIG. FIG. 8 is a cross-sectional view of the case where a windshield wall 44 having a plurality of through holes is used as the windshield wall. In this configuration, the airflow 20 that escapes to the surface side of the windshield wall 44 through the through-hole indicated by the dotted arrow in the drawing is increased as compared with the third embodiment. However, since the air volume of the flowing airflow is greatly reduced compared with the case where there is no windshield wall, the influence is small.

  As described above, even when a windshield wall having an opening is used, it is possible to configure a drying device that reduces the wraparound of the airflow to the sheet surface side and uniformly dries the coating film without distortion.

(Sixth embodiment)
FIG. 9 is a cross-sectional view showing a drying apparatus according to the sixth embodiment. The present embodiment has substantially the same configuration as the example shown in FIG. 7 of the fifth embodiment, but there is a difference in the structure of the wind shielding wall. The wind shielding wall 45 of the present embodiment has a shape in which the area ratio of the opening gradually increases as the distance from the sheet increases. When the windshield wall does not have an opening, the windshield wall suddenly disappears at the tip of the windshield wall on the side far from the sheet 10, thereby disturbing the airflow. On the other hand, in this embodiment, this disturbance can be reduced by gradually increasing the opening.

  FIG. 10 shows a specific shape example of the wind shielding wall 45. In each figure, the upper side of the drawing is the direction away from the sheet. The wind shielding wall 45a shown in FIG. 10A is formed with a higher density as the circular openings 46a having the same size are separated from the sheet. The wind shield wall 45b of FIG. 9B has an opening 46b whose area increases as the distance from the sheet increases. 9C has a slit-shaped opening 46c whose area increases as the distance from the sheet increases. The wind shield wall 45d in FIG. 9D has a corrugated opening 46d that becomes wider as the distance from the sheet increases. Note that these are merely examples, and various shapes can be used.

  As described above, according to the present embodiment, it is possible to configure a drying device that reduces the turbulence of the airflow.

  The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above embodiment. That is, the present invention can apply various modes that can be understood by those skilled in the art within the scope of the present invention.

1, 10, 102 Sheet 2, 20 Airflow 3, 30, 104 Blowout nozzle 4, 40, 41, 42, 43, 44, 45 Wind shield wall 46 Opening 50, 101 Coating film

Claims (10)

  A drying apparatus comprising: a nozzle that blows an airflow on one surface of the sheet; and a wind shielding wall that is located near an end of the sheet and reduces the wraparound of the airflow to the opposite surface of the sheet.   The drying apparatus according to claim 1, wherein the wind shielding wall has a plate shape extending in a direction away from the sheet from the vicinity of an end of the sheet.   The drying apparatus according to claim 2, wherein a direction away from the sheet is a direction from the one surface toward a surface opposite to the one surface.   The drying apparatus according to any one of claims 1 to 3, wherein the wind shielding wall has an opening.   The drying apparatus according to claim 4, wherein an area of the opening is gradually increased in a direction away from the sheet.   The drying apparatus according to claim 4, wherein the opening is divided into a plurality of parts.   A coating film is formed on the first surface of the sheet, an air current is blown on the second surface that is opposite to the first surface, and the air current wraps around the second surface in the vicinity of the end of the sheet. A method for drying a coating film, comprising disposing a windshield wall to be reduced.   The method for drying a coating film according to claim 7, wherein the wind-shielding wall has a plate shape extending in the direction away from the sheet from the vicinity of the widthwise end of the sheet.   The method for drying a coating film according to claim 8, wherein a direction away from the sheet is a direction from the first surface toward the second surface.   The said wind-shielding wall has an opening part, The drying method of the coating film as described in any one of Claim 7 thru | or 9 characterized by the above-mentioned.

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