JPH0649169B2 - Rod coater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a rod coater for applying a coating liquid to the surface of a sheet-like material to a uniform thickness.

[Prior Art] The surface of a sheet material such as a synthetic resin film, paper, or woven fabric that runs at high speed is first coated with an excessive amount of coating liquid by a coating means such as a kiss roller or fountain, and then the excess liquid is applied. A rod coater for measuring a minute coating liquid with a metering bar to obtain a prescribed thickness has been widely put to practical use because a relatively low-viscosity liquid can be coated thinly with a simple device.

The metering bar is an important measuring means that determines the coating quality of the sheet-like material since it is the final step of determining the coating thickness of the sheet-like material.

Conventionally, as such a metering bar, for example, the metering bar disclosed in Japanese Utility Model Laid-Open No. 60-100069 is known. As shown in FIG. 4, the metering bar 1 is a bar having a relatively small diameter provided in the width direction of the traveling sheet-like material 3. Also, the metering bar 1
A pair of backup rollers 4a and 4b are provided in the lower part of the sheet in order to prevent bending due to the reaction force from the sheet-like material 3 and the own weight of the metering bar 1.

Further, as shown in FIG. 5, the width W (mm) is W = Kη ^-n (K and n are constants on the outer circumferences of the backup rollers 4a and 4b, and the range is 0 <K <
7, 0.1 ≦ n ≦ 0.3. η is the viscosity of the coating liquid, and the unit is centipoise. The brim 6 having the relationship of (1) is provided.

The metaling bar 1 having such a configuration is rotated in the direction opposite to the arrow in the figure, that is, in the direction opposite to the traveling direction of the sheet-like material 3, and the backup rollers 4a and 4b are rotated at substantially the same peripheral speed of the metaling bar. By rotating at a high speed, only the excess coating liquid 2a of the coating liquid 2 applied on the back surface of the sheet-like material 1 is passed through the metalling bar 1 into the grooves 5 of the backup rollers 4a, 4b. It was induced and discharged.

In addition, as another conventional device, there is a device in which the rotating direction of the metering bar is the same as the traveling direction of the sheet-like object. Furthermore, the rotating speed is changed regardless of the rotating direction of the metering bar. Some change the thickness.

[Problems to be Solved by the Invention] However, in the conventional metaling bar 1 described above, even if the brim 6 having the above relationship is provided on the backup rollers 4a and 4b, the metaling bar is provided in the traveling direction of the sheet-like material 3. If the sheet is rotated in the opposite direction to the above, the relative speed difference is large and the sheet-like material is scratched. Therefore, when the metalling bar was rotated in the same direction as the traveling direction of the sheet-like object as indicated by the arrow, and further, the relative speed difference was reduced,
The scratch is gone. However, even in this case, if the sheet-shaped traveling speed becomes as high as 100 m / min or more, the brim 6
Excess coating liquid 2a that has reached the outer peripheral surface is scattered by the centrifugal force of the backup rollers 4a and 4b.
However, there is a problem in that it adheres to the coating surface that is beautifully coated with the specified thickness and deteriorates the coating quality.

Therefore, the present inventors provided a cover 8 behind the metering bar 1 to prevent the droplets 7 from adhering to the sheet-like material. The problem that the droplet 7 leaks occurred. Then, next, the tip of the cover was brought into contact with the metering bar, but scratches were formed on the surface of the metering bar and coating defects occurred on the coated surface, and high-speed coating while maintaining good coating quality by any of the above means. It was impossible to do.

In view of such problems of the prior art, the present invention is a rod coater that is simple and suitable for higher speed, in which excess coating liquid does not scatter from the metalling bar, backup roller, etc. even during high-speed coating of a sheet-like material. The purpose is to provide.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a coating means for applying a coating liquid to the surface of a traveling sheet material, and a rotating means in the same direction as the traveling direction of the sheet material. A metering bar provided in the width direction of the sheet for measuring the coating liquid applied by the applying means to a predetermined thickness, and a backup roller for supporting the metaling bar. In the rod coater, a scraping plate for scraping off the coating liquid adhering to the metalling bar between the sheet-like object and the backup roller is provided on the entry side of the sheet-like object and A gist of a rod coater is characterized in that the rod coater is provided at a position where a gap between the tip end surface of the take-up plate and the outer peripheral surface of the metalling bar is 0.03 to 3 mm.

Here, the rod coater of the present invention is a coating means for coating a coating liquid on the surface of a sheet-like material slightly more than a prescribed coating amount, for example, a kiss roller, a fountain and the like, and this coating liquid is prescribed. It is a coater provided with a metering means for scraping and measuring only the excess coating liquid so as to have a thickness. The metering bar, which is the metering means, is not particularly limited as long as it aims to scrape off the excess coating liquid from the coating liquid applied to the sheet-like material, but specifically, the diameter is 5 to 5. The steel roller has a small diameter of about 30 mm and is provided in contact with the sheet-shaped material in the width direction of the sheet-shaped material. In order to improve the measuring function, there are wires provided with a diameter of 0.07 to 1 mm or spiral grooves on the outer circumference. In the present invention, it is necessary that the metering bar rotates in the same direction as the traveling direction of the sheet-like material.

Further, as the peripheral speed of the metering bar, the viscosity of the coating liquid,
Depending on the conditions of the coating liquid such as temperature, the traveling speed of the sheet material, the conditions of the coated object such as surface roughness, the coating conditions such as coating thickness, coating accuracy, etc. −
It is preferably 10 to + 10%. The reason is that when the metalling bar is rotated in the same direction as the traveling direction of the sheet-shaped material and within the above speed range, the relative speed difference between the metalling bar and the sheet-shaped material becomes small and the scratches do not occur. This is because not only the wire breakage can be prevented.
Here, the same direction refers to the rotation direction of the metalling bar with respect to the sheet-like material at the contact point between the sheet-like material and the metaling bar. The metering bar may be freely rotated or actively driven within the above speed range.

Further, the backup roller is for preventing the metaling bar from bending in the direction opposite to the sheet-shaped material due to the reaction force from the sheet-shaped material and the own weight of the metalling bar itself. Similar to the metering bar, the backup roller may be continuously provided in the width direction of the sheet-like material, or may be intermittently provided. The number may be the minimum number that can prevent the bending of the metering bar from causing a practical problem. The rotation speed of the backup roller is preferably equal to or lower than the peripheral speed of the metering bar. This is because if there is a large difference in the relative speed between the two, the metalling bar is worn, and the abrasion powder adheres to the coated surface of the sheet-like material, causing a coating defect.

The reason why the scraping plate provided on such a metering bar needs to be mounted at the above-mentioned position is as follows.

First, the reason why the position of the scraping plate is on the entry side of the sheet-shaped material and between the sheet-shaped material and the backup roller is that the scraping-plate according to the present invention is the same as the sheet-shaped material. Because it rotates in the direction, the excess liquid accumulated on the upstream side in the traveling direction due to the dam effect of the metering bar needs to be removed by the scraping plate while not flowing down along the metering bar. . Therefore, by disposing the scraping plate behind the metalling bar, the excess coating liquid cannot be scraped effectively.

Further, the reason why the scraping plate is provided at a position where the gap between the tip surface and the outer peripheral surface of the metaling bar is 0.03 to 3 mm is that the metaling bar vibrates at a high speed when the gap is 0.03 mm or less. This is because the metaling bar is damaged and the coating surface is scratched, which is a coating defect, and when it is 3 mm or more, the excess coating liquid leaks out from the gap. The larger the viscosity of the coating liquid, the larger the gap. The size of this gap should be tested in advance according to the type of the coating liquid and the most effective value should be selected. In the study conducted by the present inventors, the coating liquid having a low viscosity of 3 cp was selected. However, it was found that if the gap is set to 0.5 mm, the coating defect does not occur due to the scattering of the coating solution and the re-adhesion to the metaling bar even when the traveling speed of the sheet-like material is 300 m / min.

In addition, the mounting angle of the scraping plate to the metering bar θ
Is set to 3 to 90 degrees, preferably 10 to 90 degrees, and more preferably 45 to 90 degrees with respect to the horizontal plane, although it depends on the surface tension and viscosity of the coating liquid. Mounting angle θ is 3
If it is less than the degree, the excess liquid scraped by the tip of the scraping plate cannot be discharged along the surface of the scraping plate. Incidentally, here, the value of the mounting angle θ in the vicinity of 90 degrees is set to the backup roller 14 as shown in FIG.
When a and 14b are intermittently arranged in the longitudinal direction of the metering bar 13, the values are values provided when the backup roller is not present. That is, in such a case, the scraping plates are the scraping plate 15 and the scraping plate 18.
It is formed and provided. The mounting angle θ shown in FIG.
Is defined on the front surface 20 of the scraping plate 15, but if the scraping plate 15 is not a parallel plate, the back surface 2
It is preferable to set the same value for the mounting angle θ of 2.

Further, it is preferable that the shape of the tip surface of the scraping plate is a flat surface, and that the flat surface is substantially parallel to the tangential plane at the re-approaching point of the metaling bar. By doing this, the length of the leak of the coating liquid in the gap formed by the tip surface of the scraping plate and the outer peripheral surface of the metalling bar becomes long, and the excess liquid that is about to leak from this gap is pressure-lossed. This is because the coating liquid becomes large and the coating liquid does not easily leak. Therefore, from this point of view, when the shape of the tip end surface is formed into a curved surface including a part of the cylindrical surface coaxial with the axis of the metaling bar, it is effective to reduce the amount of leakage from the gap.

The material of the scraping plate is iron, stainless steel,
Examples include metals such as aluminum and copper, nylon, acrylic resins, vinyl chloride resins, synthetic resins such as tetrafluoroethylene, and rubber. Among these, more preferable materials are synthetic resins and rubbers that do not damage the surface of the metaling bar even if they come into contact with the metaling bar when adjusting the gap or attaching the scraping plate.

The sheet material applicable to the rod coater of the present invention described above is not particularly limited, and examples thereof include synthetic resin, film, paper, and woven fabric. As the coating liquid, any known liquid which can be coated with a rod coater can be used, and its viscosity is 0.2 to 1000 c.
p, more preferably 1 to 100 cp can be applied. The traveling speed of the sheet material is not particularly limited, but it is preferably applicable to a traveling speed of 50 to 1000 m / min.

[Operation] When the sheet-like material to which the coating liquid is excessively applied reaches the metaling bar, first, the metalling bar is in contact with the sheet-like material at a constant contact pressure, so that the coating liquid having a specified thickness is applied. Only the liquid passes through, and the excess liquid blocks the passage and stagnates on the entry side of the sheet.

Next, the excess coating liquid is allowed to flow downward along the outer circumference of the metering bar due to gravity, but a scraping plate is provided close to the outer circumference of the metering bar, and the metering bar flows down. Since it is rotating in the direction to scoop up the surplus liquid to be scooped from the bottom,
The excess liquid cannot enter the gap between the metering bar and the scraping plate, and stays on the upper surface of the scraping plate. When the amount of stagnation becomes a certain amount or more, the scraping plate is inclined, so that the excess coating liquid flows down along the upper surface of the scraping plate,
Let it drain.

Here, even if a part of the excess liquid leaks from the gap between the metering bar and the scraping plate, this excess liquid is prevented from being dropped by the shearing force to the coating liquid due to the rotation of the metaling bar, so that the scraping plate And is discharged along the back surface of the scraping plate.

[Embodiment] An embodiment of the present invention will be specifically described below with reference to the drawings.

1 and 2 are sectional views showing an embodiment of a rod coater according to the present invention (a sectional view taken along the line AA in FIG. 2).
FIG.

In the figure, 9 indicates a width of 1 traveling in the direction of the arrow in the figure.
It is a sheet-like material made of a 000 mm polyester film, and the coating liquid 12 is applied to the back surface of the bread 10 by a kiss roller 11.

13 is a stainless metaling bar having a diameter of 20 mm, a wire diameter of 0.15 mm, and a length of 1200 mm. Reference numerals 14a and 14b are backup rollers made of synthetic resin having a diameter of 20 mm and a width of 20 mm, and support the metering bar 13 from below. Although only one pair of pack-up rollers is shown in the figure, actually four pairs are provided in the length direction of the metering bar 13. 15
Is a scraping plate for scraping off the excess coating liquid 16 from the sheet-like material, and the mounting position of the tip end of the scraping board is on the entry side of the sheet-like material and between the sheet-like material and the backup roller. And the mounting angle θ is 15 degrees with respect to the horizontal plane, and the clearance a between the tip surface of the scraping plate and the outer peripheral surface of the metalling bar is a.
Is attached by a bracket (not shown) so as to be 0.5 mm. This scraping plate 15 has a thickness of 3 mm.
Of synthetic resin, and the shape of the tip surface 17 is finished to be a cylindrical surface coaxial with the axis of the metering bar 13. Further, as shown in FIG. 1, the opening portions 15 and 18 are sufficiently effective if they are provided only on the entry side, but a cover 8 as shown in FIG. 4 may be added to the discharge side.

Further, FIG. 3 is a sectional view taken along the line BB of FIG. 2 in which the metalling bar is not supported by the backup roller.

In the figure, 18 is a scraping plate made of synthetic resin and having a thickness of 3 mm. In this position, the scraping plate 18 is formed separately from the scraping plate 15, and 50 mm from the end is attached to overlap with the scraping plate 15 as shown in FIG. The scraping plate 18 is mounted such that the mounting angle θ is 45 degrees with respect to the horizontal plane and the gap b is 0.5 mm, and the shape of the tip surface 19 is a flat surface, and the metaling bar is closest to the scraping plate. Finished almost parallel to the tangent plane at the point. In the present embodiment, the sizes of the gaps a and b are the same, but it goes without saying that they may be different from each other within the scope of the present invention. Further, in the present embodiment, the scraping plates are the scraping plate 15 and the scraping plate 18.
Backup roller 14
At a position where a and 14b are not applied, the scraping plate may be composed of one continuous member.

With a rod coater constructed in this way, the viscosity is 1
An aqueous solution of 0 cp of low melting point polyester was applied to the kiss roller 1
When the coating thickness was 50 μm and the running speed was 150 m / min, the excess coating liquid 15 did not leak from the gap a at the tip of the scraping plate 15, and the excess coating liquid 16 It was discharged along the upper surface 20 of the scraping plate 15. Further, in the scraping plate 18, most of the excess coating liquid was removed, and a part of the excess liquid leaked from the gap b, but since it flowed down along the back surface of the scraping plate along 21,
The coating film after the measurement had a beautiful specified thickness without causing the defect of splashing due to the centrifugal force of the conventional metaling bar and backup roller.

[Effects of the Invention] As described in detail above, the load coater of the present invention scrapes off excess coating liquid on the entry side of the sheet-shaped material and between the sheet-shaped material and the backup roller. Since the scraping plate is attached at a position where the gap between the tip of the scraping plate and the metaling bar is 0.03 to 3 mm,
Excessive coating liquid is removed from the coating surface by the scraping plate, and it is possible to easily prevent the excessive coating liquid from being scattered by the centrifugal force of the metaling bar, the backup roller and the like.

Further, in this case, since the mounting angle of the scraping plate is set to 3 to 90 degrees with respect to the horizontal plane, the excess coating liquid is smoothly discharged. Furthermore, the shape of the tip surface of the scraping plate is a cylindrical surface or a plane coaxial with the axis of the metering bar, and the plane is substantially plane with respect to the tangent plane at the closest point of the metering bar. Therefore, leakage of the excess coating liquid from the gap formed by the metalling bar and the scraping plate is further prevented.

Therefore, the rod coater of the present invention can apply the traveling speed of the sheet material at a high speed of 50 to 1000 m / min, which greatly contributes to the cost reduction of the application cost of the sheet material.

[Brief description of drawings]

1 and 2 are a sectional view (a sectional view taken along the line AA of FIG. 2) and a plan view showing an embodiment of a rod coater according to the present invention, and FIG. It is a BB arrow sectional drawing of a figure. 4 and 5 are a sectional view and a partial side view of a conventional rod coater. Description of reference numerals in the drawings 1, 13 ... Metalling bar 2, 12 ... Coating liquid 2a, 16 ... Excess coating liquid 3, 9 ... Sheet material 4a, 4b, 14a, 14b ... Backup roller 17 , 19 ...... Tip surface of scraping plate 15, 18 …… Scraping plate θ …… Mounting angle of scraping plate a …… Gap between scraping plate 15 and metaling bar 13 b …… Scraping plate 18 Gap with the metering bar 13

Claims (4)

[Claims] 1. A coating means (10, 11) for coating a coating liquid (12) on the surface of a traveling sheet-like article (9), and rotating in the same direction as the traveling direction of the sheet-like article (9), A metering bar (13) provided in the width direction of the sheet-like material (9) for measuring the coating solution (12) applied by the applying means (10, 11) to a predetermined thickness; A rod coater provided with backup rollers (14a, 14b) for supporting a metering bar (13), comprising: the sheet-like material (9) and the backup roller (14).
a, 14b) and a scraping plate (15, for scraping off the coating liquid (12) attached to the metalling bar (13).
18) is the entry side of the sheet-like material (9) and is the tip surface (17, 1) of the scraping plate (15, 18).
A rod coater provided at a position where a gap (a, b) between 9) and the outer peripheral surface of the metalling bar (13) is 0.03 to 3 mm. 2. The rod coater according to claim 1, wherein an attachment angle (θ) of the scraping plates (15, 18) is 3 to 90 degrees with respect to a horizontal plane. 3. A tip surface (1) of a scraping plate (15, 18).
The rod coater according to claim (2), characterized in that the shape of (7, 19) is formed into a curved surface including a part of a cylindrical surface coaxial with the axial center of the metering bar (13). 4. A tip surface (1) of a scraping plate (15, 18).
The shape of (7, 19) is a plane, and the plane is substantially parallel to the tangent plane at the closest point of the metering bar (13). Rod coater.