JPH0975815A - Coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device capable of obtaining an excellent sheet in which thickness of a coated layer is uniform in the cross direction after coating treatment and difference of thickness and thinness is prevented and also capable of being continuously operated for a long period. SOLUTION: Coating liquid 11 is applied to a continuously traveling sheet 8 by a liquid-sticking roll 12 and thereafter coating liquid is weighed and regulated by a weighing instrument 9. The coating device is constituted by installing coaters 6 provided with the surface parts which are expanded by air pressure and brought into contact with the traveling sheet 8 on the uncoated surface side of the sheet 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus, and more particularly to a metering bar type coating apparatus.

[0002]

2. Description of the Related Art Conventionally, when a liquid such as paint is applied to a sheet such as paper or film, it can be applied at a relatively high speed and a smooth coating surface can be obtained. In the following, a coating device is simply used). An applicator roll system has been proposed as such a coating device. An example of an applicator roll type coating device is shown in FIG.

As shown in the figure, the applicator roll type coating device C50 is used for the applicator roll 12
Is rotatably dipped in the paint 11 stored in the paint tank 10. When this applicator roll 12 is rotated, the picked-up paint is transferred on the surface of the applicator roll 12 as it is rotated, and the paint is transferred from the surface of the applicator roll 12 to the back surface of the sheet 8 running. As a result, the sheet 8 continues to run in a state where the coating material is thickly deposited on the back surface of the sheet 8.

When the sheet 8 reaches a predetermined position in the subsequent stage, the metering bar 9 which rotates in reverse comes into contact with the paint placed on the back surface of the sheet 8, and a part of the paint is removed from the back surface of the sheet 8. . Here, by adjusting the position of the metering bar 9, the paint adhered on the back surface of the sheet 8 is weighed to a predetermined amount, excess paint is removed, and the surface of the coating layer is smoothed. is there.

[0005]

However, in the conventional applicator roll type coating apparatus as described above, when the traveling sheet has a partial waviness due to tabbing or ears on the edges, The metering bar cannot evenly measure the paint, and as a result, a problem occurs that excessive paint is applied to the tabbed portion and the corrugated portion. For this reason, a coating layer having a uniform thickness cannot be obtained, and there is a possibility that problems relating to product quality may occur, such as partial drying failure of the coating layer and occurrence of slit processing failure due to difference in thickness of the coated paper. It was

The present invention has been made to solve the above problems and drawbacks of the prior art. The purpose of the present invention is to make the coating layer uniform in the width direction after the coating treatment so that there is no difference in thickness. An object of the present invention is to provide a coating apparatus which can obtain an excellent sheet and can be continuously operated for a long period of time.

[0007]

SUMMARY OF THE INVENTION A coating apparatus according to the present invention is a coating apparatus in which a coating liquid is applied to a continuously running sheet with a liquid applying roll and then the coating liquid is measured by a coating liquid measuring device. It is characterized in that it is provided with a coater having a surface portion which is inflated by air pressure and comes into contact with a traveling sheet on the surface side. Alternatively, the coater that expands due to the air pressure includes a frame and a surface portion. Alternatively, the length of the coating device that expands due to the air pressure is longer than the width of the coated sheet.

Alternatively, the coating device that expands due to the air pressure is installed before and after the coating liquid measuring device. Alternatively, the coating liquid meter is a metering bar. Alternatively, the coating device that expands due to the air pressure is installed before and after the liquid application roll.

The compressive strength of the coater provided with the surface portion which expands by the air pressure is 0.5 kg / cm 2 or more. Alternatively, the dynamic friction coefficient of the surface portion of the applicator in contact with the traveling sheet is 0.2 or less. Alternatively, the surface portion in contact with the running sheet is configured by stacking an elastic sheet having a Young's modulus of 10 5 dyne / square cm or more and a sheet having a dynamic friction coefficient of 0.2 or less. To do.

With the above-mentioned structure, in the coating apparatus according to the present invention, the surface portions of the coating device arranged before and after the metering bar, which is the coating liquid measuring device, are expanded by air pressure and the sheet is not coated. Since the sheet comes into contact with the surface side or is appropriately pressed, tension acts on the sheet to remove the unevenness of the sheet and correct the sheet to a flat surface. Therefore, the contact of the coated sheet with the coating liquid meter is uniformly adjusted in the width direction of the sheet.
This allows the paint to be measured to a uniform thickness across the width,
The excess paint is scraped off, and at the same time, the surface of the coating layer is smoothed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a coating apparatus of the present invention will be described below with reference to the accompanying drawings. First, the structure of the coating apparatus of the present invention will be described.

FIG. 1 is an explanatory view of the constitution of an embodiment of a coating apparatus according to the present invention. As shown in FIG. 1, a coating apparatus 1 according to the present invention is a coating tank 1 in which a coating 11 is stored.
The coating part Pa provided with an applicator roll 12 which is a rotating roll, the lower part of which is dipped in 0, and a guide roll 7 which guides the traveling of the sheet 8, and the coating part Pa which is provided in the latter part of the coating part Pa and measures the thickness of the coating layer. A reverse rotation bar (metering bar) 9 which is a coating liquid meter to be adjusted and coating devices 6 and 6 are arranged, and a coating layer adjustment including a guide roll 7 and a backing roll 13 for guiding the traveling of the sheet 8 is provided. And Ad. The coating portion Pa coats the coating liquid on the coating surface side of the sheet 8 which is the object to be coated, and the coating layer adjusting portion Ad adjusts the coating surface of the sheet 8.

The coaters 6 each having a surface portion 60 that expands by air pressure are provided before and after the reverse rotation bar 9 of the coating layer adjusting portion Ad, and each surface portion of each coater 6, 6 expands. Sometimes, it is arranged so as to be in contact with the non-coated side of the sheet 8.

FIG. 2 is an external view of the coating device 6 incorporated in the coating device 1. The coater 6 includes a box-shaped frame 63 and an inflatable surface portion 60.
0 is provided so as to close the opening of the frame 63. As a result, the inside of the applicator 6 is configured in a sealed state that can withstand the pressure.

Further, a pipe 64 to which the pressure gauge 5 for measuring the pressure inside the frame is attached is attached to the frame 63. The box-shaped frame 63 is preferably configured to have a compressive strength of 0.5 kg / square cm or more, and is further preferably configured not to be deformed even when the air pressure is 3.0 kg / square cm. Further, it is desirable that the dynamic friction coefficient of the surface portion 60 is 0.2 or less. Further, the length of the applicator 6 is preferably longer than the width of the coated sheet 8.

FIG. 3 is a cross-sectional view showing the state of the coating device 6 when low air pressure is supplied. The surface portion 60 has a Young's modulus of 5
A rubber-like elastic body 61, which is an elastic sheet having a power of dyne / square cm or more, and a highly slippery sheet 62 having a dynamic friction coefficient of 0.2 or less with respect to a running base material are stacked.

The rubber-like elastic body 61 is made of natural rubber or various synthetic rubbers, and its characteristics are that the reversible elastic region of the mouse is 50 to 800% and Young's modulus (initial) is 10%.
6 to 10 7 dyne / square cm. Further, the highly slippery sheet 62 more preferably has a dynamic friction coefficient of 0.1 or less.

When air Air having an air pressure of 0.5 kg / cm 2 is supplied through the compressed air pressure adjusting valve 4, the rubber-like elastic body 61 and the highly slippery sheet 62 are about 15 to 25 mm as shown in the drawing. Expands.

FIG. 4 is a cross-sectional view showing the state of the coating device 6 when a relatively high air pressure is supplied. The air pressure is 1 kg / square cm.
When the air Air is supplied, the rubber-like elastic body 61 and the highly slippery sheet 62 are 30 to 40 mm as shown in the figure.
Expands to some extent.

The dimensions (width, length, height) of the coating device 6 according to the present invention are not particularly limited.
It can be realized in any suitable size. Further, the dimensions and characteristics of the rubber 61 and the high slip sheet 62 used for the surface portion 60 are not particularly limited.

In the embodiment, the rubber 61 is 0.5 mm.
A thick neoprene rubber sheet was used, and as the high slip sheet 62, a glass cloth impregnated with a fluorine resin (trade name: Chuko Flow Sheet) was used.

Next, the operation will be described. The sheet 8 unwound from the sheet winding (not shown) is guided by each guide roll 7 and then the coating material 11 is applied to the back surface by the applicator roll 12. The sheet 8 coated with the paint 11 is subsequently measured by the reverse rotation bar 9, but the coating devices 6, 6 provided before and after the reverse rotation bar 9 expand due to air pressure, and the sheet 8 Non-coated side,
That is, it acts on the front surface to give tension to the sheet 8.

As a result, the irregularities formed on the sheet 8 are removed, and the sheet 8 becomes a flat surface and reaches the reverse rotation bar 9. Reverse rotation bar 9 is a flat sheet 8
Therefore, the reverse rotation bar 9 hits the applied sheet 8 uniformly in the width direction of the sheet, and the paint is evenly measured in the width direction. Excess paint is scraped off. Further, the surface of the coating layer is smoothed. The tension applied to the sheet 8 can be adjusted by the air pressure supplied to the coating device 6.

[0024]

【Example】

Example 1 A base paper having a corrugation on one side (a fine paper having a thickness of 70 μm, a width of 1700 mm and a basis weight of 65 g / square meter) was wound up,
The coating device of the present invention is arranged in front of and behind the rotary bar, and air having a pressure of 1.0 kg / square cm is supplied to each coating device to expand it, thereby applying tension to the base paper to coat 100 m / min. The electron-donating colorless dye was applied at a speed, weighed, and dried. The paper tension, the heat-sensitive liquid coating amount, and the color density on the rotary bar at this time are as shown in FIG.

The tension of the paper was measured by measuring the both sides of the paper with a tension pick-up roll, and the tension was applied per cm of paper width. The coating amount of the heat-sensitive liquid was calculated from the weight difference of A4 size after the base paper and the coated paper were dried at 105 ° C. for 2 hours. Color density is 150 degrees Celsius in a thermal gradient tester,
After printing for 2 seconds at a pressure of 2 kg / cm2, Macbeth R after 3 minutes
The concentration was measured with D-914.

Comparative Example 1 When the heat-sensitive liquid was applied under the same conditions as in the examples except that the coating device, which is an essential part of the present invention, was removed, the results shown in FIG. 6 were measured.

FIG. 7 is an explanatory view of the constitution of another embodiment of the coating apparatus according to the present invention. As shown in the figure, the applicators 6, 6 including the surface portion 60 that expands by air pressure are
As described above, in addition to being provided before and after the reverse rotation bar 9 of the coating layer adjusting unit Ad, respectively, it is also provided before and after the applicator roll 12 of the applying unit Pa. That is, it was clarified that the effect is further exhibited by installing the coating device before and after the applicator roll of the coating solution.

[0028]

The coating apparatus of the present invention is provided with a coating device which can apply tension to the non-coating side of the sheet due to expansion due to air pressure at positions before and after the coating liquid meter,
This removes partial tab marks and corrugations on the sheet, so the contact of the sheet with the coating liquid meter can be adjusted uniformly in the width direction. It is possible to obtain an excellent sheet with no difference.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of a coating apparatus according to the present invention.

FIG. 2 is an external view of a coating device incorporated in the coating device according to the present invention.

FIG. 3 is a cross-sectional view showing a state of the applicator shown in FIG. 2 during low air pressure supply.

FIG. 4 is a cross-sectional view showing a state of the applicator shown in FIG. 2 when high air pressure is supplied.

FIG. 5 is a table showing operation results of an example of the coating apparatus according to the present invention.

FIG. 6 is a table showing operation results of a comparative example of a conventional coating device.

FIG. 7 is an explanatory diagram of a configuration of another embodiment of a coating apparatus according to the present invention.

FIG. 8 is an explanatory diagram of a configuration of a conventional coating device.

[Explanation of symbols]

 1 Coating Equipment 6 Coating Machine 7 Guide Roll 8 Sheet 9 Rotation Metering Bar (Coating Liquid Meter) 10 Paint Tank 11 Paint 12 Applicator Roll 13 Backing Roll 15 Coated Sheet

Claims (9)

[Claims] 1. A coating device in which a coating liquid is applied to a continuously traveling sheet by a liquid application roll and then the coating liquid is measured and adjusted by a coating liquid measuring device, and the sheet non-coated surface side is inflated by air pressure and travels. A coating apparatus comprising a coating device having a surface portion in contact with a sheet. 2. The coating apparatus according to claim 1, wherein the coating device that expands due to air pressure comprises a frame and a surface portion. 3. The length of the coating device that expands due to the air pressure is longer than the width of the coated sheet.
Alternatively, the coating device according to claim 2. 4. The coating apparatus according to claim 1, wherein the coating device that expands due to the air pressure is installed before and after the coating liquid meter. 5. The coating apparatus according to claim 4, wherein the coating liquid meter is a metering bar. 6. The coating apparatus according to claim 4, wherein the coating device that expands by the air pressure is also installed before and after the liquid dipping roll. 7. The coating according to any one of claims 1 to 6, wherein a pressure resistance of a coating device having a surface portion that expands by air pressure is 0.5 kg / square cm or more. Engineering equipment. 8. The coating apparatus according to claim 1, wherein a dynamic friction coefficient of the surface portion of the coating device in contact with a running sheet is 0.2 or less. . 9. The surface portion contacting a running sheet,
9. An elastic sheet having a Young's modulus of 10 <5> dyne / square cm or more and a sheet having a dynamic friction coefficient of 0.2 or less are superposed on each other.
The coating apparatus according to the item.