JP2012171334A - Drying device and drying method of paint film on roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dry a paint film on an anilox roll efficiently and uniformly.SOLUTION: A controller 6 makes strength adjustment for an air flow of an internal space 2A of a housing 2 by controlling a pressure regulating valve 5008 of each suction path and adjusting a suction force of each suction port 5004 based on the detection result of a detector 3. Namely, the thickness of paint film 4 is made uniform along the longitudinal direction of the anilox roll 1 by strengthening or weakening the entire air flow when the entire thickness of paint film 4 is a threshold or more or less than the threshold or by strengthening the air flow in the position where the thickness of paint film 4 is the threshold or more or weakening the air flow in the position where the thickness of paint film 4 is less than the threshold. Namely, the thickness of paint film 4 is made uniform by adjusting the steam density of the air which touches the paint film 4 according to the strength of the air flow and adjusting the evaporation rate of the solvent contained in the paint film.

Description

  The present invention relates to a drying method capable of performing a drying step in order to obtain a desired film thickness and liquid properties in a coating film (coating film) applied on a roll, and a coating film drying apparatus on the roll. More specifically, the present invention relates to a drying apparatus and a drying method for a coating film on a roll that can supply liquid physical properties and liquid volume suitable for printing to a plate of a relief printing apparatus.

  In recent years, production competition for higher-definition and beautiful displays has intensified. Among them, organic electroluminescent elements (hereinafter referred to as organic EL elements), color filters, and the like are attracting attention as satisfying the demand for higher definition and thinner layers. These organic EL elements and color filters require a fine patterning technique.

  As a typical method for performing the fine patterning required above, there is a photolithography method. In the photolithography method, fine patterning is performed by removing unnecessary portions after forming a coating film on the entire substrate. There is a problem of becoming.

  In addition to the photolithography method, an offset printing method is known in which a silicone blank is used as a printing blanket, and printing ink is transferred from the printing blanket to a substrate such as glass as a substrate to be printed. . However, this method has a drawback that the ink in the non-image area where the pattern is not formed is removed by the printing plate and discarded.

  Therefore, in recent years, a letterpress printing method excellent in ink mileage is attracting attention in place of such a method. The relief printing method is a printing method in which an image line portion has a convex shape, that is, a relief plate is used as a printing plate, ink is held on the projection and transferred to a substrate to be printed.

  This relief printing apparatus includes an anilox roll for supplying a liquid to the relief plate, a rotary plate cylinder on which a relief plate for pattern formation is mounted via an under-print cushion, a substrate surface plate on which a substrate to be printed is placed, The anilox roll has a doctor or the like for scraping off excess ink.

  Here, the amount of ink supplied to the surface of the relief printing plate is greatly influenced by the wettability of the printing plate, the pattern shape of the relief printing plate, the ink viscosity, the number of mesh lines of the anilox roll, and the cell volume (groove volume) of the mesh. . Further, the increase or decrease in the amount of ink supplied to the letterpress surface also increases or decreases the thickness of the print transfer film onto the substrate to be printed that is the final product.

  In a letterpress printing device, in order to form a pattern with high precision from the letterpress to the substrate to be printed and to apply the optimum film thickness required for the product, adjust the physical properties of the ink transferred from the anilox roll to the letterpress, or letterpress It is necessary to control the amount of ink supplied to the surface. In order to perform these controls, there is a method of scraping off liquid other than the anilox roll cell using a doctor blade or a doctor roll as in Patent Document 1 and Patent Document 2. However, in this method, when different ink supply amounts are required, it is necessary to use different anilox roll mesh line numbers or cell volumes.

JP-A-57-2760 JP-A-60-135920 JP 2010-46980

  As described above, regarding the control for optimal transfer from the relief printing plate to the substrate to be printed in the conventional relief printing apparatus, when the control is performed with the number of mesh lines of the anilox roll or the cell volume, the change of the ink material or the process condition With each change, the optimum number of mesh lines and cell volume of the anilox roll must be evaluated each time, and there is a problem that the load becomes very large in terms of cost.

  Further, even when drying on an anilox roll, if it takes time to dry, the productivity is greatly adversely affected. Furthermore, when unevenness occurs in the coating liquid on the anilox roll in the drying process, problems tend to occur in transfer to the substrate to be printed, which is the final product, and an accurate pattern cannot be formed, leading to quality deterioration.

  Also, in the drying process, installing a large device that can control the drying of the entire anilox roll just for drying is not desirable because it takes away the cost and space for other processes, and it is a simpler method. Was desired.

The present invention has been devised in view of the above circumstances, and the invention according to claim 1 dries the coating film on the roll formed by applying the coating liquid to the outer peripheral surface of the rotating roll. A drying apparatus is provided that includes a housing having an internal space capable of accommodating a full length portion of the outer peripheral surface along a longitudinal direction of the roll at a part of the outer peripheral surface of the roll on which the coating film is formed. And
Suction means connected to the housing for sucking air in the internal space and generating an air flow in the internal space is provided.
According to a second aspect of the present invention, a plurality of suction ports for sucking air in the internal space are provided at intervals in the longitudinal direction of the roll, and the coating is applied at a plurality of locations spaced in the longitudinal direction of the roll. Detection means for detecting the thickness of the film is provided, and control means for controlling the suction force at each suction port according to the detection result of the detection means is provided.
According to a third aspect of the present invention, the suction means includes a suction source and a plurality of suction paths that connect the suction ports and the suction source, respectively. It is characterized by including a pressure regulating valve provided in the suction path.
According to a fourth aspect of the present invention, the roll is an anilox roll that supplies ink to a relief printing plate of a relief printing apparatus.
The invention according to claim 5 is characterized in that the thickness of the coating film is 50 μm or less.

The invention described in claim 6 is a drying method for drying a coating film on a roll formed by applying a coating liquid on the outer peripheral surface of a rotating roll, which is formed on the outer peripheral surface. The coating film is exposed to an air flow to reduce the vapor density of the air in contact with the coating film.
In the invention according to claim 7, the thickness of the coating film is detected at a plurality of locations spaced in the longitudinal direction of the roll when the vapor density of the air in contact with the coating film is reduced, and the thickness is detected. The strength of the air flow is adjusted according to the thickness of the coating film.

According to the present invention, a housing that covers a part of the roll is installed on the roll, and suction is performed by a suction means that sucks out air with a high solvent atmosphere inside the housing, thereby improving the drying speed and the process. It was a short time.
Furthermore, the thickness of the coating film on the roll is detected by the detection means, the suction is controlled while checking the state of the left and right unevenness, and the coating film is uniformly dried by rotating the roll and drying it, An appropriate pattern could be created on the substrate to be printed as the final product.
As a result, liquid physical properties and liquid volume on the roll can be quickly controlled, and production efficiency has been improved. In addition, the liquid properties and volume can be controlled in a short time, and the conditions of the coating liquid for generating the pattern are widened, so it is possible to select a coating liquid that improves the performance and cost of the final product. Become.

  By covering a part of the roll with the housing, if the suction speed in the covered housing is uniform only in the width direction, the drying will be performed uniformly. Thus, when left and right unevenness is confirmed during drying, control for eliminating the unevenness is facilitated.

  In addition, since the housing covers a part of the roll, the size of the device itself may be smaller than the device that controls the drying of the entire roll, which is very advantageous in terms of cost and space occupied by the device. is there.

Side view showing the overall configuration of the drying device Sectional drawing which shows the positional relationship of a drying apparatus and a roll Perspective view of drying device Diagram showing viscosity change with drying

In FIG. 1, the housing (suction member) 2 is arranged so as to cover a part of the anilox roll 1. Furthermore, in order to remove the unevenness of the film thickness due to the difference in the drying speed in the width direction, a detecting means 3 for detecting the thickness of the coating film is disposed in the vicinity of the anilox roll 1. Since the anilox roll 1 is rotating, the position of the detection means 3 may be any position as long as observation in the vicinity of the anilox roll 1 is possible.
More specifically, the drying apparatus of the present invention includes a housing 2 and suction means 5.
The housing 2 has an internal space 2A that can accommodate the entire length of the outer peripheral surface along the longitudinal direction of the anilox roll 1 at a part of the outer peripheral surface of the anilox roll 1. An opening 2002 having a size larger than the entire length of the outer peripheral surface is formed.
The suction means 5 is connected to the housing 2 and sucks air in the internal space 2A to generate an air flow in the internal space 2A.
Further, the drying apparatus of the present invention includes a detection unit 3 that detects the thickness of the coating film 4 on the anilox roll 1, and a control unit 6 that controls the suction force by the suction unit 5 according to the detection result of the detection unit 3. It has.
The suction means 5 includes a suction source 5002, a plurality of suction ports 5004 provided in the housing 2 and opening into the internal space 2 </ b> A, and suction paths 5006 that connect the suction ports 5004 and the suction source 5002. The plurality of suction ports 5004 are provided in the housing 2 at intervals in the longitudinal direction of the anilox roll 1.
A pressure adjusting valve 5008 controlled by the control means 6 is attached to a suction path connecting each suction port 5004 and the suction source 5002.
Here, the detecting means 3 for detecting the thickness of the coating film 4 on the anilox roll 1 applies light to the coating film 4 and reflects the reflection angle of the reflected light or the thickness of the coating film 4 based on the amount of reflected light. Various conventionally known methods such as a method for detecting the thickness can be employed. For example, the thickness of the coating film 4 is detected at a plurality of locations at intervals in the longitudinal direction of the anilox roll 1.
The control unit 6 controls the pressure adjustment valve 5008 of each suction path based on the detection result of the detection unit 3 and adjusts the suction force of each suction port 5004 to adjust the strength of the air flow. That is, when the thickness of the coating film 4 is generally equal to or greater than the threshold value and less than the threshold value, the air flow is generally strengthened or weakened, or at a location where the thickness of the coating film 4 is equal to or greater than the threshold value. Or the thickness of the coating film 4 is made uniform along the longitudinal direction of the anilox roll 1 so that the air flow is weakened at a location where the thickness of the coating film 4 is less than the threshold value.
That is, the thickness of the coating film 4 is made uniform by adjusting the vapor density of the air in contact with the coating film 4 according to the strength of the air flow and adjusting the evaporation rate of the solvent contained in the coating film.

  During the suction, the anilox roll 1 is rotated in order to perform uniform drying in the circumferential direction. The speed is adjusted so that the coating does not fall off, and splashing due to rotation or uneven coating does not occur. 100 [mm / sec] or more is desirable.

  In FIG. 2, the housing 2 is installed in the vicinity of the anilox roll 1. At this time, the anilox roll 1 does not need to enter the inside of the housing 2, but it is preferable that the anilox roll 1 enters the inside of the housing 2 in order to increase the drying speed and increase the efficiency.

  As shown in FIG. 3, in order to control drying unevenness in the width direction during the drying process, as a mechanism capable of controlling the air volume in the width direction, for example, a plurality of suction ports 5004 (suction nozzles) are installed, and the drying is slow By increasing the suction speed, uniform drying can be realized.

  The evaporation rate of the solvent in the coating film 4 depends on the vapor pressure of the solvent and the vapor density of the atmosphere, and the vapor pressure of the solvent depends on various conditions such as temperature. Among these, the range in which the temperature and vapor pressure can be implemented is determined by the physical properties and heat resistance of the solvent to be used. Therefore, it is desirable to lower the vapor density in promoting drying. In order to lower the vapor density, an air flow may be artificially generated in the vicinity of the coating film 4.

  In order to perform uniform drying, it is desirable that suction can be performed at a uniform suction speed in the width direction. This is because the suction speed difference in the width direction tends to cause drying unevenness.

  In order to perform uniform suction perpendicular to the width direction, for example, it is more desirable to use the housing 2 having a suction slit having a sufficiently wide width with respect to the anilox roll 11.

As a method of applying the liquid to the anilox roll 1, various conventionally known methods such as die coating and anilox roll 1 coating can be employed. Regardless of the method applied, the film thickness can be controlled by drying according to the present invention.
That is, in the drying method of the present invention, the entire length portion of the outer peripheral surface along the longitudinal direction of the anilox roll 1 in the circumferential direction portion of the anilox roll 1 on which the coating film 4 on the anilox roll 1 is formed is air. By exposing to the flow, the vapor density of the air in contact with the entire length of the outer peripheral surface along the longitudinal direction of the anilox roll 1 in a part of the outer peripheral surface of the anilox roll 1 was lowered.
Therefore, according to this invention, the drying rate of the coating film 4 on the anilox roll 1 can be improved, and it becomes possible to perform a drying process in a short time.
Further, the thickness of the coating film 4 at a plurality of locations along the longitudinal direction of the anilox roll 1 is detected by the detection means 3, and the strength of the air flow is adjusted according to the detected thickness of the coating film 4. Thus, the vapor density of the air in contact with the coating film 4 is adjusted, and the thickness of the coating film 4 is made uniform along the longitudinal direction of the anilox roll 1.

  In order to carry out the present invention, it is more desirable that the film thickness on the anilox roll 1 is very thin, particularly when the film thickness is 50 μm or less. This is because the present invention can be carried out even when the film thickness is thick, but the effect of the present invention is easily exhibited when the film is a thin film in which unevenness and the like are likely to cause problems.

  In order to more specifically describe the present invention, the following examples will be used.

<Example 1>
Each condition is described below.
a) The anilox roll 1 has a diameter L of 100 mm and a width of 300 mm.
b) The rotation speed of the anilox roll 1 was set to 100 [mm / s].
c) The initial film thickness applied to the anilox roll 1 was 16 μm.
d) The surface tension of the coating solution used is 33.7 [mN / m].
e) The viscosity of the coating solution used is 14 [mPa · s] at the time of coating.
f) In order to accurately perform patterning on the substrate to be printed, the viscosity needs to be in the range of 40 to 60 [mPa · s].
g) Since the liquid contains a polymer solute, the viscosity increases with drying. The viscosity change accompanying drying is shown in FIG.

Using the liquid under the above conditions and the anilox roll 1, coating was first performed on the anilox roll 1 using a die, and drying was performed with the apparatus shown in FIG. Thereafter, the liquid was inked into the relief plate, and further patterned into a substrate to be printed. As a result of applying a negative pressure to each suction port 5004 and generating an air flow with an air volume of 0.12 [m ³ / s] in the internal space 2A, a good pattern could be created by a drying process of 23 seconds.

<Comparative Example 1>
When the anilox roll 1 and liquid under the same conditions as in Example 1 were used and the drying apparatus of the present invention was not used, the required drying time was 82 seconds, which was significantly increased compared to Example 1. In addition, in the same 21-second drying step as in Example 1, deterioration in quality was confirmed, for example, the pattern transferred to the substrate to be printed was not cut properly.

  For the production of functional elements in general using a relief printing apparatus, the drying apparatus and the drying method of the present invention can be used, and a higher quality functional element can be produced at low cost and with low load. .

DESCRIPTION OF SYMBOLS 1 ... Anilox roll 2 ... Housing 2A ... Internal space 2B ... Suction chamber 2C ... Suction nozzle 3 ... Detection means 4 ... Coating means 5 ... Suction means 5002 ... Suction source 5004 ... Suction port 5006 ... Suction passage 5008 ... Pressure adjustment valve 6 ... Control means L ... Diameter of the anilox roll 1

Claims (7)

A drying device for drying a coating film on a roll formed by applying a coating liquid on the outer peripheral surface of a rotating roll,
A housing having an internal space capable of accommodating the entire length of the outer peripheral surface along the longitudinal direction of the roll at a part of the circumferential direction of the outer peripheral surface of the roll on which the coating film is formed;
A suction means connected to the housing for sucking air in the internal space and generating an air flow in the internal space;
An apparatus for drying a coating film on a roll. A plurality of suction ports for sucking air in the internal space are provided at intervals in the longitudinal direction of the roll,
Detection means for detecting the thickness of the coating film is provided at a plurality of positions spaced in the longitudinal direction of the roll,
Control means for controlling the suction force at each suction port according to the detection result of the detection means is provided,
The apparatus for drying a coating film on a roll according to claim 1. The suction means includes a suction source and a plurality of suction paths that connect the suction ports and the suction source, respectively.
The control means includes a pressure regulating valve provided in each suction path.
The apparatus for drying a coating film on a roll according to claim 2.   4. The apparatus for drying a coating film on a roll according to claim 1, wherein the roll is an anilox roll that supplies ink to the relief printing plate of the relief printing apparatus.   The apparatus for drying a coating film on a roll according to any one of claims 1 to 4, wherein the thickness of the coating film is 50 µm or less. A drying method for drying a coating film on a roll formed by applying a coating liquid on the outer peripheral surface of a rotating roll,
The coating film formed on the outer peripheral surface was exposed to an air flow, and the vapor density of the air in contact with the coating film was lowered.
A method for drying a coating film on a roll. When reducing the vapor density of the air in contact with the coating film, the thickness of the coating film is detected at a plurality of positions spaced in the longitudinal direction of the roll, and the thickness of the coating film is determined according to the detected thickness of the coating film. I adjusted the strength of the air flow,
The method for drying a coating film on a roll according to claim 6.

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