JP4961785B2 - Method and apparatus for adjusting die head coating gap - Google Patents

Description

  The present invention relates to a coating technique for coating a running web such as a sheet or film using a die head.

  Conventionally, as one of apparatuses for coating a web such as a sheet-like base material with a high viscosity and poor wettability, as shown in FIGS. 5 and 6, a backup roll 1 having a soft rubber film 1 a on its surface. In addition, a coating apparatus including a die head 2 disposed so as to face the backup roll 1 is known. In this coating apparatus, the tip of the die head 2 is pressed against the web 3 supported by the backup roll 1, or the die head 2 is held at a position where a gap of 0 to several tens of microns is generated between the die head 2 and the web 3. A coating gap having an appropriate dimension d is formed between the tip 3 of the die head 2 and the rubber film 1a on the surface of the backup roll 1 by micro-deformation by discharging the coating liquid from the surface. The bead 4a formed in the coating gap is stabilized and the wettability is improved by increasing the pressure of the bead portion, and the web 3 is coated uniformly in the width direction with a desired film thickness.

In this type of coating apparatus, the pressure of the dimensions and the bead portion of the coating gap has a significant impact on the coating characteristics, it is too large coating gap, the pressure of the bead portion is not sufficiently high, on the web 3 A coating film cannot be formed, and stable coating cannot be performed. Further, if the coating gap is not constant in the web width direction, a missing portion or a thick coating portion occurs, and the film thickness unevenness in the web width direction increases. Therefore, conventionally, a displacement sensor (not shown) is attached to both ends of the die head 2, and the distance between the surface of the rubber film 1 a of the backup roll 1 and the tip of the die head is measured with the displacement sensor, and the measured value is based on the measured value. The position of the die head 2 with respect to the backup roll 1 is adjusted, and the amount of pressing of the die head tip against the surface of the backup roll 1 or the gap formed between the surface and the surface of the backup roll without discharging liquid (hereinafter referred to as this pressing amount). Alternatively, the gap dimension is adjusted so that the initial gap dimension is an appropriate value (so that a coating gap capable of forming a coating film is formed during coating). However, with this adjustment method, measurement is performed by directly applying a displacement sensor to the rubber film 1a, which is a soft material that is difficult to produce a cylindricity, so the obtained numerical value is not reliable, and the initial gap size should be adjusted accurately. However, it is actually an inappropriate value.For this reason, a missing portion or a thick coating portion may occur and the film thickness may become uneven in the width direction. In some cases, the film itself could not be formed. Further, the displacement sensor attached to the die head needs to be removed every time the die head is washed. At that time, it is difficult to obtain the reproducibility of the displacement sensor in the left and right direction in units of microns.

  The present invention has been made in view of such a problem, and provides a die head coating gap adjusting method and a coating apparatus that can appropriately adjust a coating gap without using a displacement sensor and perform good coating. Is an issue.

As a result of investigations to solve the above problems, the present inventors have found the following matters. That is, in a state in which performing coating operation the supply flow rate of the coating liquid into die head as constant and gradually changing the distance between the die head and the backup roll, the pressure of the bead portion with the magnitude of the applied gap also changes changes, there is a region where the size and pressure of the bead portion of the coating gap is the value suitable for forming a coating film, moreover, the hydraulic pressure of the coating solution in the die head in response to changes in pressure in the bead portion (e.g. , hydraulic pressure in the manifold) are also changed, from the liquid pressure, the magnitude and pressure bead portion of the coating gap is identifiable whether a value suitable for the film formation. Therefore, in advance, the size and scope of the hydraulic pressure in the die head in a state where the pressure of the bead portion is a value suitable for forming a coating film of the coating gap (hereinafter, referred coatable pressure range) seeking if put to measure the fluid pressure in the die head during the coating operation, by the measured value to adjust the distance between the die head and the backup roll such that the fluid pressure of coatable pressure range, coating the coating gap It can be adjusted to a value suitable for formation, and good coating can be performed. In addition, during the coating operation, there is a difference in the coating gap in the left and right end regions of the die head, and when large film thickness unevenness occurs in the web width direction, there is also a difference in the fluid pressure in the die head in the left and right regions of the die head, The film thickness unevenness can be suppressed by adjusting the inclination of the die head with respect to the backup roll so that this difference is eliminated.

The present invention has been made on the basis of such knowledge, and the die head coating gap adjusting method of the invention according to claim 1 is made to run by supporting a web on a backup roll having a rubber film on the surface and facing the backup roll. The high-viscosity coating liquid is discharged from the arranged die head onto the web supported by the backup roll, and the rubber film is deformed by the discharge pressure to apply a coating gap having an appropriate dimension between the die head tip and the web. In the coating method of forming a bead due to the coating liquid in the coating gap and coating the web running between the backup roll and the die head, during the coating operation of discharging the coating liquid from the die head, The liquid pressure measurement process that measures the liquid pressure of the coating liquid in the die head, and the measured liquid pressure forms the coating film. Is obtained by a structure having a coating gap adjustment step of adjusting the distance of the backup roll and the die head so that the ability pressure.

  The invention according to claim 2 is the die head coating gap adjustment method according to claim 1, wherein the hydraulic pressure measuring step includes a differential pressure measuring step of measuring a hydraulic pressure difference between left and right regions in the die head. The application gap adjusting step includes a left and right application gap adjusting step of adjusting the distance between the backup roll and the die head at the left and right ends of the die head based on the measured hydraulic pressure difference.

The invention according to claim 3 is provided with a backup roll having a rubber film on the surface, and a die head disposed opposite to the backup roll, the web being run on the backup roll, and a high viscosity from the die head. A coating liquid is discharged onto the web supported by the backup roll, and the rubber film is deformed by the discharge pressure to form a coating gap having an appropriate dimension between the tip of the die head and the web. In a coating apparatus configured to apply a bead due to a coating liquid and apply to a web traveling between the backup roll and the die head, a liquid pressure measuring device that measures a liquid pressure of the coating liquid in the die head; and comprising a coating gap adjusting device for adjusting the distance of the backup roll and the die head, said fluid pressure measuring device On left and right areas of the manifold of the die head, there is provided a coating apparatus characterized in that it comprises an arrangement pressure sensors to measure the fluid pressure in the manifold.

According to a fourth aspect of the present invention, in the coating apparatus according to the third aspect , the coating gap adjusting device is provided in each of left and right end regions of the die head, and adjusts the distance between the backup roll and the end of the die head. The application gap adjusting means is provided.

  The die head coating gap adjusting method of the present invention measures the coating liquid pressure in the die head during the coating operation in which the coating liquid is discharged from the die head, and adjusts the distance between the backup roll and the die head based on the measured value. Thus, the coating gap can be set to a value suitable for coating film formation, and satisfactory coating can be performed at all times. Further, since there is no need to use a displacement sensor, problems associated with using a displacement sensor can be avoided.

  Here, in the measurement of the hydraulic pressure in the die head, the hydraulic pressure difference between the left and right areas in the die head is obtained, and the distance between the backup roll and the die head at the left and right ends of the die head is adjusted based on the hydraulic pressure difference. The difference between the coating gaps at the left and right ends of the film can be reduced, and the occurrence of a missing portion or thick coating portion can be suppressed during coating, thereby reducing the film thickness unevenness in the web width direction.

Since the coating apparatus of the present invention includes a fluid pressure measuring device that measures the fluid pressure of the coating liquid in the die head and a coating gap adjusting device that adjusts the distance between the backup roll and the die head, the coating of the present invention described above. By implementing the gap adjustment method, the coating gap can be set to a value suitable for coating film formation, and satisfactory coating can always be performed.

Furthermore, in the coating apparatus according to the present invention, the hydraulic pressure measuring device includes pressure sensors arranged to measure the hydraulic pressure in the manifold in the left and right areas of the manifold of the die head, respectively. The pressure in the region can be measured and the position can be adjusted so that a coating gap is formed so that the die head can be coated as a whole. Here, the application gap adjusting device is provided in each of the left and right end regions of the die head and includes end application gap adjusting means for adjusting the distance between the backup roll and the end of the die head. The gap difference can be adjusted to be small, and the occurrence of a missing portion or a thick coating portion during application can be suppressed, so that the film thickness unevenness can be suppressed small.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention shown in the drawings will be described. 1 is a schematic perspective view of a coating apparatus according to an embodiment of the present invention, FIG. 2 is a schematic plan view of the coating apparatus, FIG. 3 is a schematic sectional view of the coating apparatus, and FIG. It is a schematic sectional drawing which expands and shows an area | region, and attaches | subjects the same code | symbol to the same or similar components as the prior art example shown in FIG. The coating apparatus according to the present embodiment includes a backup roll 1 that conveys a web 3 such as a sheet-like base material wound around a part of the outer peripheral surface, a die head 2 that is disposed to face the backup roll 1, and a die head 2 is provided with a fluid pressure measuring device 11 for measuring the coating fluid pressure in 2 and a coating gap adjusting device 12 for adjusting the distance between the backup roll and the die head.

  The backup roll 1 is provided with a soft rubber film 1a on at least a region of the outer peripheral surface that guides the web 3, and can be deformed by the discharge pressure of the coating liquid from the die head 2. The die head 2 has a slit 6 for discharging the coating liquid 4 and a manifold 7 for supplying the coating liquid to the slit 6. The manifold 7 has an external coating liquid supply device (not shown). A supply pipe 8 for supplying the coating liquid from is connected.

  The hydraulic pressure measuring device 11 is for measuring the coating hydraulic pressure in the die head 2 directly or indirectly. In this embodiment, the hydraulic pressure in the supply pipe is located in the region near the die head 2 of the supply pipe 8. That is, the first pressure sensor 14a provided to measure the liquid pressure in the liquid supply passage leading to the die head manifold and the right and left regions of the manifold 7 in the die head 2 are measured. Pressure sensors 14b and 14c arranged in this manner, a data converter 15 that receives signals from these pressure sensors 14a, 14b, and 14c, and a signal that is input from the data converter 15 and displays the measured hydraulic pressure A control device 16 such as a personal computer having a display unit is provided. The pressure sensors 14b and 14c arranged in the left and right regions of the manifold 7 are used to estimate the size of the coating gap at both ends of the die head from the respective measured values and to make the coating gap at both ends of the die head uniform from the difference in measured values. In order to increase the detection accuracy, it is preferable that the manifold 7 is disposed at a position close to both ends of the manifold 7 and at a symmetrical position with respect to the center line in the width direction of the die head. The control function by the control device 16 will be described later.

  The coating gap adjusting device 12 is for adjusting the distance between the web 3 supported by the backup roll 1 and the tip of the die head 2 by moving the die head 2 so as to approach or separate from the backup roll 1. In this embodiment, end coating gap adjusting means 18a and 18b provided in both end regions of the die head 2 are provided. The end coating gap adjusting means 18a and 18b are respectively attached to the screw head 19 that rotates at a fixed position, a motor 20 that rotationally drives the screw shaft 19 and the die head 2, and meshes with the screw shaft 19. A ball nut 21 and the like are provided. The motors 20, 20 arranged on the left and right sides are controlled by the control device 16 so as to rotate separately, and are also controlled so that both rotate in synchronization. With this configuration, by synchronously rotating the motors 20 and 20, the die head 2 can be moved so as to approach or move away from the backup roll 1 while maintaining a certain posture. By individually rotating, the distance between the tip of the die head 2 and the web 3 on the backup roll 1 at each end of the die head 2 can be adjusted.

  In the control device 16 described above, under various coating conditions, a coating gap suitable for coating film formation is formed in advance, and the fluid pressure in the die head with respect to a state where the bead portion pressure is a value suitable for coating film formation. The range, i.e., the applicable hydraulic pressure range, is entered. This applicable liquid pressure range may be calculated by flow analysis in the die head, or by actually performing a coating test under various conditions and measuring the upper and lower limits of the hydraulic pressure at which good coating can be performed. You may ask for it. In most cases, the upper limit of the liquid pressure is calculated from the allowable pressure limit of the liquid supply device such as a pump, piping, die head or the like.

Next, a coating operation and a coating gap adjustment operation by the coating apparatus having the above configuration will be described. Prior to the start of the coating operation, the controller 16 is operated to operate the end coating gap adjusting means 18a and 18b on both sides of the die head 2 so that the die head 2 is positioned at the initial setting position with respect to the backup roll 1. At the initial setting position, when the discharge of the coating liquid from the die head 2 is started, the rubber film 1a of the backup roll 1 is deformed by the discharge pressure, and a coating gap having a size capable of performing good coating is formed. However, it is not always necessary to use an accurate position. The coating operation is started with the die head 2 in the initial setting position. That is, the discharge of the coating liquid from the die head 2 and the running of the web 3 are started. When the coating liquid is discharged from the die head 2, the rubber film 1 a of the backup roll 1 is deformed by the discharge pressure, and a coating gap is generated between the tip of the die head 2 and the web 3. bead 4a is formed at a position, the coating is carried out. At this time, the dimension d of the coating gap varies depending on the dimension between the tip of the die head and the surface of the backup roll when the coating liquid is not discharged, that is, the initial gap dimension, and the ejection pressure and the liquid in the manifold are accordingly changed. The pressure is also different. As described above, when the die head 2 is set to the initial setting position, the initial gap dimension is not necessarily constant in the web width direction, and does not always have a value that allows good coating. . Therefore, simultaneously with the start of application, the hydraulic pressure measuring device 11 starts measuring the hydraulic pressure in the die head 2, and the control device 16 inputs the hydraulic pressure measured by the pressure sensors 14a, 14b, and 14c. Monitor whether it is within the possible hydraulic range. If the measured hydraulic pressure is out of the applicable hydraulic pressure range, the control device 16 operates one or both of the end application gap adjusting means 18a and 18b to finely adjust the position of the die head 2. Adjust and control the measured hydraulic pressure to be within the applicable hydraulic pressure range. Further, the pressure difference between the pressure sensors 14b and 14c arranged on the left and right sides is obtained, and either one or both of the end coating gap adjusting means 18a and 18b are operated accordingly, and the position of the die head 2 is determined. Are adjusted so that the measured differential pressure becomes small. As a result, during application, the dimension d of the application gap is maintained at a dimension that allows good application, and the left and right variations are reduced, and application with a small film thickness difference can be continuously performed in the width direction.

  In the above-described embodiment, the liquid pressure measured by the three pressure sensors 14a, 14b, and 14c is used for adjusting the coating gap, but the measured values of only the pressure sensors 14b and 14c arranged in the left and right regions of the die head. The application gap may be adjusted using In that case, the central pressure sensor 14a may be omitted, or the measurement value obtained by the pressure sensor 14a may be used for monitoring so that an excessively high pressure is generated in the system and no trouble occurs. May be.

  In the above-described embodiment, the control device 16 controls the end application gap adjusting means 18a and 18b based on the hydraulic pressure measurement result in the die head to automatically adjust the application gap. The invention is not limited to this configuration, and the operator may adjust the coating gap by manually adjusting the end coating gap adjusting means 18a, 18 based on the hydraulic pressure measurement result in the die head at an appropriate period. . Further, in the above embodiment, the hydraulic pressure difference in the left and right regions of the die head 2 is measured, and the left and right positions of the die head 2 are adjusted based on the result. However, uneven coating thickness in the web width direction is allowed. In this case, the right and left positions of the die head are not necessarily adjusted, and the die head 2 may be adjusted as a whole so as to form a coating gap that can be applied. Even in such a case, it is preferable to control the liquid pressure in the die head 2 so that the measurement values at the three positions shown in the illustrated embodiment fall within the preset allowable range. However, in some cases, the number of measurement points is small, and for example, it may be changed to use only the central pressure sensor 14a. Further, in the above description of the operation, the applicationable fluid pressure range, which is a fluid pressure range suitable for application, is input to the control device 16 and the application gap is adjusted based on this range. The hydraulic pressure range is not limited to this, and a configuration may be adopted in which an optimum coating fluid pressure range in which optimum coating can be performed by further narrowing is input and the coating gap is adjusted based on the optimum coating fluid pressure range. By adopting this configuration, it is possible to perform better coating.

  In order to confirm the effect of the present invention, a coating test was performed using a coating apparatus having the configuration shown in FIG. The outer diameter of the backup roll 1 used was 300 mm, the rubber hardness of the rubber film 1a was 70 °, the discharge width of the die head 2 was 920 mm, and the slit gap was 500 μm.

  In this coating apparatus, a polyester film having a thickness of 250 μm was run at a speed of 30 m / min, and UV curable resin having a viscosity of 2000 cp was discharged from the die head 2 at a flow rate of 500 cc / min. During this coating operation, the fluid pressure is measured by the pressure sensors 14b and 14c, and the edge coatings provided on the left and right sides of the die head 2 are set so that the fluid pressure has the values shown in Tests 1, 2, 3, and 4 of Table 1. The gap adjusting means 18a and 18b were operated, the coating gap was adjusted, and the coating film formation state was observed. Moreover, the film thickness nonuniformity of the web width direction was measured about the sample obtained by apply | coating by the tests 3 and 4. FIG. The results are shown in Table 1. In measuring the film thickness unevenness, the entire film thickness including the polyester film is measured, and the film thickness unevenness is obtained from the results. For this reason, the film thickness unevenness of the polyester film itself is obtained. (The film thickness unevenness of a 250 μm polyester film is usually about 5 to 10%).

  As is clear from the results of Tests 1, 2, and 3 in Table 1, when the liquid pressure in the die head was 0.12 MPa, the coating film could not be formed, but the position of the die head 2 was adjusted to adjust the liquid in the die head. Good coating was possible by setting the pressure to 0.24 MPa and 0.48 MPa. Therefore, it was confirmed that good coating can be performed by monitoring the fluid pressure in the die head and adjusting the position of the die head 2 so that the fluid pressure is appropriate. Further, as apparent from Tests 3 and 4 in Table 1, it was confirmed that the film thickness unevenness in the web width direction can be reduced by eliminating the hydraulic pressure difference between the left and right.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and it is needless to say that the present invention can be appropriately changed within the scope of the claims.

Schematic perspective view of a coating apparatus according to an embodiment of the present invention Schematic plan view of the coating apparatus shown in FIG. Schematic sectional view of the coating apparatus shown in FIG. FIG. 1 is an enlarged schematic cross-sectional view showing a coating liquid discharge area in the coating apparatus shown in FIG. Schematic cross-sectional view of a conventional coating device FIG. 5 is a schematic cross-sectional view showing an enlarged coating liquid discharge area in the coating apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Backup roll 1a Rubber film 2 Die head 3 Web 6 Slit 7 Manifold 8 Supply pipe 11 Hydraulic pressure measuring device 12 Coating gap adjustment device 14a, 14b, 14c Pressure sensor 15 Data converter 16 Control device 18a, 18b End coating gap adjustment means 19 Screw shaft 20 Motor 21 Ball nut

Claims (4)

Surface caused to travel by supporting the web on the backup roll having a rubber coating, discharged into the backup roll opposite, a coating solution of a high viscosity from the placed die head on the web which is supported by the backup roll, the discharge pressure The rubber film is deformed to form a coating gap having an appropriate size between the tip of the die head and the web, and a bead is formed in the coating gap by the coating liquid, and the belt runs between the backup roll and the die head. In the coating method for coating on the web, during the coating operation in which the coating liquid is discharged from the die head, a liquid pressure measuring step for measuring the liquid pressure of the coating liquid in the die head and the measured liquid pressure can form a coating film. A coating gap adjusting step of adjusting a distance between the backup roll and the die head so as to be a pressure; Die head coating gap adjustment method characterized by and.   The hydraulic pressure measuring step includes a differential pressure measuring step of measuring a hydraulic pressure difference between left and right regions in the die head, and the coating gap adjusting step is performed at both left and right ends of the die head based on the measured hydraulic pressure difference. 2. The die head coating gap adjusting method according to claim 1, further comprising a left and right coating gap adjusting step of adjusting a distance between the backup roll and the die head. A backup roll provided with a rubber film on the surface, and a die head disposed opposite to the backup roll, and supported by the backup roll and supported by the backup roll. Discharge onto the web, the rubber film is deformed by the discharge pressure to form a coating gap of an appropriate size between the tip of the die head and the web, and a bead of coating liquid is generated in the coating gap. In the coating apparatus configured to apply to the web traveling between the backup roll and the die head, the liquid pressure measuring apparatus for measuring the liquid pressure of the coating liquid in the die head, and the distance between the backup roll and the die head are adjusted. comprising a coating gap adjustment device for the fluid pressure measuring device, Mani said die head On left and right areas of Rudo, coating apparatus characterized in that it comprises an arrangement pressure sensors to measure the fluid pressure in the manifold. The said application | coating gap adjustment apparatus is provided in the right-and-left both ends area | region of the said die head, respectively, The edge part application | coating gap adjustment means which adjusts the distance of the said backup roll and die head edge part is provided. Coating device.

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