JP4621138B2 - Curtain coating equipment - Google Patents

Description

  The present invention relates to a curtain coating apparatus for dropping a curtain made of a liquid film and coating the film on the surface of a traveling plate.

  In the curtain coating method, a liquid film can be formed by a curtain coating apparatus, the liquid film can be freely dropped as a curtain, the curtain collides with a traveling plate, and the film can be coated on the surface of the plate. Patent Document 1 describes a curtain coating method in which a curtain is formed as a liquid film having a plurality of layers and a plurality of layers are coated on the surface of a traveling plate, and particularly, the production of multilayer photographic materials is handled.

  Curtains that fall freely from the curtain coating device cause a contraction in which the width of the curtain narrows as it goes downwards when the curtain is dropped freely without restraining the end in the width direction of the curtain. Therefore, the end in the width direction of the curtain is regulated by the curtain guide, and the width of the curtain during free fall is held at a predetermined width. The curtain guide is suspended from both ends of the curtain width at the curtain flow position of the curtain coating apparatus. Patent Document 2 describes a curtain guide in which a flexible neck-in preventing member formed of a spherical chain is suspended and a weight is attached to the lower end of the neck-in preventing member.

  If the curtain width is equal to or narrower than the plate width at the coating position on the plate, the thickness of the film coated on the surface of the plate tends to increase at the edge in the width direction. May not be maintained. On the other hand, when the width of the curtain is made wider than the width of the plate at the site of coating on the plate, the thickness of the film coated on the plate can be made uniform in the width direction.

  When the width of the curtain is made wider than the width of the plate, the curtain portion located outside the both ends of the width of the plate will fall below the plate. A pan for receiving the dropped curtain is provided below the plate. Accordingly, the lower end of the curtain guide that guides the width end of the free-fall curtain is positioned below the position of the plate. Patent Document 3 relates to an apparatus for coating a steel sheet with a slide hopper type curtain coating apparatus, characterized in that a chain-shaped curtain guide is provided as a curtain guide, and the distance between the curtain guides is wider than the coating material. Yes. Therefore, the curtain guide hangs down to the bottom of the paint pan below the steel plate.

  If the curtain is wider than the width of the plate, the falling curtain part outside the width of the plate may be recovered and reused as a curtain liquid film material if the curtain is a single-layer liquid film. it can. However, when a plurality of layers of liquid film is applied as described in Patent Document 1, the curtain is a plurality of layers of liquid film even in the curtain portion that falls outside both ends of the width of the plate. It becomes a mixture of two or more different compositions and cannot be reused as a curtain liquid film raw material.

  In the invention described in Patent Document 4, one of the plurality of liquid films constituting the curtain is larger than the width of the web (plate), and the other layer has a width that does not overflow the web. . As a result, since the liquid film overflowing from the edge of the web is a single layer, this overflowing composition can be collected and recycled into the liquid feed of the same composition layer. Here, a layer having a width larger than the width of the web and having the same width as the curtain width is called a wide layer, and a layer having a width that does not overflow the web is called a narrow layer.

Japanese Patent Publication No.49-24133 JP 2001-246300 A JP-A-6-190323 Japanese Patent Publication No.62-47075

  When painting on the surface of a continuous steel strip using a curtain coating device, the strip change part of the steel strip is also continuously coated by welding the steel strip ends of both lots. For such lot changing parts, the width of the steel strip and the coating specifications are often changed, and it is necessary to change the curtain width and curtain film thickness. During such changes, it is convenient to place a shutter between the curtain coating device and the steel strip to prevent the coating liquid falling on the steel strip from the curtain coating device from adhering to the surface of the steel strip. It is. In addition, when two or more multilayer films are coated with a curtain coating apparatus, it is necessary to measure the film thickness of each layer, so a shutter may be disposed between the curtain coating apparatus and the steel strip.

  Since the shutter arranged for the above purpose needs to receive the coating liquid of the entire width of the curtain, the width of the shutter is wider than the width of the curtain and is arranged between the curtain coating apparatus and the steel strip. By the way, when the curtain width is wider than the width of the steel strip, the curtain guides arranged at both ends of the curtain width as described above have their lower ends arranged below the position of the steel strip. Therefore, even if an attempt is made to insert the shutter between the curtain coating device and the steel strip, the shutter cannot be inserted because the curtain guide gets in the way.

  If the curtain guide 5 can be raised, the space between the curtain coating apparatus 1 and the plate 7 is vacant so that a shutter can be inserted into the space. As shown in FIG. 5 (a), when the lower end (weight 5b) of the curtain guide 5 is lifted upward by the string 17, the middle portion of the curtain guide (flexible member 5a) sags downward and remains. In the slack area, the paint drops and contaminates the surface of the board. Further, as shown in FIG. 5B, when the lower end (weight 5b) of the curtain guide 5 is raised in the lateral direction by the string 17, the middle portion of the curtain guide can be avoided, but the paint guide Will be scattered around and will also contaminate the surface of the plate.

  An object of the present invention is to provide a curtain coating apparatus having a curtain guide for guiding both width ends of a free-falling curtain, in which a shutter can be inserted between the curtain coating apparatus and a material to be coated.

That is, the gist of the present invention is as follows.
(1) In the curtain coating apparatus 1 that freely drops the liquid film curtain and coats the surface of the traveling plate 7, the curtain guide 5 that guides both ends of the free-falling curtain 6, and the elevation that moves the curtain guide 5 up and down The curtain guide 5 is formed by suspending a flexible long material 5a, and the lower end portion of the elevating device 8 arranged above the curtain guide 5 is an intermediate position of the curtain guide 5. The curtain coating device is characterized in that the curtain guide 5 can be moved upward by the lifting device 8.
(2) The curtain guide 5 has a weight 5b at the lower end thereof, and the portion of the lifting device 8 connected to the intermediate position of the curtain guide is disposed through the storage guide 10, and the lower end of the storage guide 10 is the curtain coating device. The curtain coating apparatus according to (1), wherein the curtain coating apparatus protrudes downward from the curtain falling part of 1.
(3) The curtain coating apparatus 1 is a slide curtain coating apparatus, and the upper end of the curtain guide 5 is suspended from the inner side in the width direction from both width ends of the slide 3, and the storage guide 10 is placed on the outer side in the width direction at both width ends of the slide 3. The curtain coating apparatus according to (2), wherein the curtain coating apparatus is provided in contact with each other.
(4) Further, a shutter 9 which can be inserted between the curtain coating apparatus 1 and the plate 7 and can receive the coating liquid is provided, and when the shutter 9 is inserted below the curtain coating apparatus 1, The curtain coating apparatus according to any one of (1) to (3), wherein the guide 5 is raised upward.

  In the present invention, the curtain guide of the curtain coating apparatus can be raised upward, and a shutter can be inserted between the curtain coating apparatus and the material to be coated. The curtain guide can be lifted without being scattered or dropped by being tied in the middle position.

  The present invention can be applied to any curtain coating apparatus that forms a film by discharging a film of paint from one or more slits, dropping the film as a free-falling curtain, and applying the film onto a moving plate. Various methods and apparatuses may be used.

  As the curtain coating apparatus 1 of the present invention, a slide curtain coating apparatus as shown in FIG. 1 can be used. The slide curtain coating device has one or more slits 2 and when paint is discharged from each slit 2, the discharged paint becomes a liquid film, which is a single layer film or a multilayer film corresponding to the number of slits. The liquid flows down along the slide 3, leaves the slide 3 at the slide end 4, and falls freely as a liquid film curtain 6. Below the slide curtain coating apparatus 1, a plate 7 as an object to be curtain coated is running. The liquid film curtain 6 that has dropped onto the surface of the plate 7 adheres to the surface of the plate 7 while maintaining a single-layer or multilayer state, and a coating film is formed on the surface of the plate 7.

  As another curtain coating method, it is possible to use a die coater device that forms a multilayer film by discharging paint from multiple adjacent slits without using a slide, and simultaneously forms a multilayer coating film using a free-fall curtain. It is equivalent to a slide curtain coating device in that it can be done.

  In the following, description will be given by taking as an example the case where a coating layer is applied to the surface of a continuous metal plate using a slide curtain coating apparatus.

  The slide curtain coating apparatus 1 has one or two or more slits 2. When the paint is discharged from each slit 2, the discharged paint becomes a liquid film and flows down along the slide. For example, in a slide curtain coating apparatus having three slits as shown in FIG. 1, the liquid film discharged from the first slit 2a flows down on the slide to the position of the second slit 2b, and the second slit 2b. A two-layer liquid film is formed in contact with the liquid film discharged from the second layer, and the two-layer liquid film flows down to the third slit 2c and comes into contact with the liquid film discharged from the second slit 2c. A liquid film is formed. The liquid film formed on the slide 3 includes a liquid film discharged from the first slit 2a in the uppermost layer, a liquid film discharged from the second slit 2b in the next layer, and a third slit in the lowermost layer. It is formed in layers in the order of the liquid film discharged from 2c. The width end of the liquid film on the slide 3 is guided by the edge guide 11. The three-layer liquid film flows down along the slide 2, leaves the slide 3 at the slide end 4, and freely falls as a three-layer multilayer film curtain 6. The width end of the curtain 6 is guided by the curtain guide 5. Below the slide curtain coating apparatus, a metal plate 7 is running as an object to be curtain coated. The multilayer curtain that has fallen on the surface of the metal plate adheres to the surface of the metal plate while maintaining the multilayer state, and a plurality of layers of coating films are formed on the surface of the metal plate.

  When the metal plate travels in the direction of the metal plate traveling direction 22 shown in FIG. 1, the liquid film discharged from the third slit 2c forms the lowest layer closest to the metal plate 7, and is discharged from the first slit 2a. The liquid film thus formed forms the uppermost layer. If the traveling direction of the metal plate is opposite to the direction shown in FIG. 1, the stacking order of the liquid films on the metal plate 7 is reversed.

  As described above, when the curtain coating apparatus 1 is used, as shown in FIG. 1, if the width of the curtain 6 is made wider than the width of the plate 7 at the portion to be coated on the plate 7, the thickness of the film coated on the plate 7 is increased. The thickness can be made uniform in the width direction.

  As described above, when the curtain 6 that freely falls from the curtain coating apparatus 1 is freely dropped without restraining the end in the width direction of the curtain 6, a contracted flow in which the curtain width narrows as it goes downward is generated. Therefore, the end in the width direction of the curtain 6 is regulated by the curtain guide 5, and the width of the curtain during free fall is held at a predetermined width. The curtain guide 5 is suspended from both ends of the curtain width at the curtain flow position of the curtain coating apparatus (or the slide end 4 in the case of the slide curtain coating apparatus). In general, a material that does not have flexibility can be used as the curtain guide 5, but in the present invention, the curtain guide 5 is constituted by a long material having flexibility (flexible member 5a). The chain shown in FIG. 1B, the spherical chain shown in FIG. 1C, and the string can be used. A weight 5b is arranged at the lower end of the curtain guide 5 so that the hanging state of the curtain guide 5 can be stabilized. When the curtain width is narrower than the width of the plate to be painted, the lower end of the curtain guide is placed at the very edge of the plate surface. When the curtain width is wider than the width of the plate to be painted, the lower end portion of the curtain guide 5 is arranged further below the plate surface as shown in FIG.

  The present invention has a lifting device 8 that lifts and lowers the curtain guide 5. The operation will be described with reference to FIG. The lower end of the lifting / lowering device 8 disposed above the curtain guide 5 is connected to an intermediate position (connecting portion 12) of the curtain guide 5, and the curtain guide 5 can be lifted upward by the lifting / lowering device 8. The lifting / lowering device 8 can have a wire portion 8a connected to the curtain guide 5 and a winding portion 8b for winding up the wire. The lower end of the wire part 8a is connected to the connection part 12 at the intermediate position of the curtain guide.

  In the state where the wire portion 8a is rolled down, the curtain guide 5 is not restrained by the elevating device 8 and is kept suspended from the slide end 4 as shown in FIGS. When the wire portion 8a is wound up by the operation of the winding portion 8b, the connecting portion 12 of the curtain guide 5 moves upward, and accordingly, the curtain guide 5 ascends upward as a whole (FIGS. 2C and 2D).

  When the curtain guide 5 is sufficiently wound up, as shown in FIG. 2 (e), all the flexible members 5a having the flexibility of the curtain guide 5 move above the slide end 4, and the curtain guide 5 The lower end weight 5b is positioned near the slide end 4. In this state, if the curtain guide 5 does not exist at all for the free-falling curtain, the situation is the same, so that a stable contracted flow is formed, and the paint drops as shown in FIG. Scattering of paint as shown in (b) does not occur.

  In the state where the curtain guide is sufficiently wound up, as shown in FIGS. 2 (e) and 2 (f), since there is no obstacle between the curtain coating device 1 and the metal plate 7, a shutter 9 is disposed in the space. The falling curtain 6 or paint can be received by the shutter 9.

  For example, when painting a metal plate, before starting painting, a shutter 9 is arranged between the curtain coating device 1 and the metal plate 7 as shown in FIGS. 9 is collected and discarded. When painting continuous strip steel, the painting specifications may change in the middle of the coil. By providing the shutter 9 under the curtain coating apparatus 1, it is possible to prevent the paint from scattering on the adjacent steel strip of different specifications, and to prevent the paint from scattering to the slitting coil. After the welding point of the strip has passed, the shutter 9 is moved and coating on the metal plate 7 is started.

  In addition, if the movement of the metal plate suddenly stops or decelerates due to operational troubles, it is necessary to stop the curtain falling from the curtain coating device to prevent the coating thickness on the metal plate surface from becoming abnormally thick. However, even if the discharge of the paint from the slit 2 of the curtain coating apparatus 1 is stopped, the curtain drop cannot be stopped immediately and the paint drops from the slide end 4. In such a case, if the curtain guide 5 is lifted by the lifting / lowering device 8 of the present invention and the shutter 9 is inserted into the lower part of the curtain coating device, it is possible to prevent the paint from dropping on the stopped metal plate. It becomes possible.

  As an intermediate position (connecting portion 12) for connecting the wire portion 8a of the lifting / lowering device 8 to the curtain guide 5, the weight 5b at the lower end of the curtain guide is raised to the position of the slide end 4 in a state where the curtain guide 5 is sufficiently raised. However, the position may be such that the flexible member (5a) of the curtain guide is exposed and does not dangle. It is preferable that the intermediate point of the flexible member 5a is the connecting portion 12.

  The lifting device 8 of the present invention can be provided with a storage guide 10 as shown in FIG. The storage guide 10 has a cylindrical shape, and the wire portion 8 a of the elevating device 8 is disposed in the storage guide 10. When the wire portion 8a is wound up, the portion connected to the intermediate position (connecting portion 12) of the curtain guide 5 in the lifting device 8, that is, the wire portion 8a is disposed in the storage guide 10, and the curtain guide 5 is adjusted accordingly. The flexible long material (flexible member 5 a) is also stored in the storage guide 10. When the lower end of the curtain guide 5 has the weight 5b, if the inner diameter of the storage guide 10 is made smaller than the outer diameter of the weight 5b, the weight 5b is located below the storage guide 10 in a state where the curtain guide is sufficiently raised. It stabilizes in contact with the tip (FIG. 3B). In the present invention, the lower end portion of the storage guide 10 is preferably protruded downward from the curtain dropping portion of the curtain coating apparatus (the slide end 4 in the case of the slide curtain coating apparatus). Thereby, when the curtain guide 5 is raised to the upper end, the trouble that the weight 5b collides with the slide end 4 and damages the slide end can be avoided. The distance from the slide end 4 to the lower end of the storage guide (distance b in FIG. 3C) is preferably about 1 mm.

  When the curtain coating apparatus is a slide curtain coating apparatus, the upper end of the curtain guide 5 is suspended from the vicinity of both ends of the width of the slide end 4. At this time, it is preferable that the upper end of the curtain guide 5 is hung from the inner portion of the slide end 4 rather than the outermost portion in the width direction. Here, a distance from the outermost portion in the width direction of the slide end to the upper end of the curtain guide is set as a as shown in FIG. If the upper end of the curtain guide 5 is hung from the outermost part in the width direction of the slide end 4 (a = 0), the curtain edge stabilizing effect due to the wraparound of the paint cannot be sufficiently obtained. On the other hand, when the upper end of the curtain guide 5 is hung from a portion 3 mm or more inward from the outermost portion in the width direction of the slide end 4 (a ≧ 3 mm), the curtain edge stabilizing effect can be sufficiently obtained. Here, the curtain edge stabilizing effect is a stabilizing effect due to the curtain film being separated from the curtain guide, and is that a curtain non-forming state is not generated. The drop velocity distribution in the width direction of the curtain film is lower in the vicinity of the curtain guide than in the center due to the viscous resistance of the paint. Therefore, if the paint is not sufficiently supplied to the boundary portion between the curtain film and the curtain guide, the curtain film is cut off from the thinned portion. By placing the upper end position of the curtain guide inside, it is possible to compensate for the shortage of paint supply at the edge due to the wraparound of the paint, and the effect of stabilizing the curtain film can be obtained. On the other hand, when the suspended portion of the curtain guide 5 is disposed at a position exceeding 5 mm inward from the outermost portion in the width direction of the slide end 4 (a> 5 mm), the width of the slide 3 is not fully used and curtain coating is performed. This is not preferable because the possible width becomes narrow and the paint flowing down from the vicinity of both ends in the width direction of the slide does not wrap around the curtain guide and droops unnecessarily.

  Further, the storage guide 10 is provided in contact with the width direction outside of both ends of the width of the slide 3 so that the storage guide itself does not become a factor that hinders the flow of the curtain, and when the curtain guide 5 is raised, it is straight. This is preferable because it can be raised upward.

  In the curtain coating apparatus of the present invention, when the shutter 9 is inserted below the curtain coating apparatus 1, if the curtain guide 5 is lifted upward by the elevating device 8, the shutter 9 is inserted and the curtain guide 5 is lifted. Can be performed simultaneously in conjunction with each other, so that it is possible to quickly change from a steady curtain coating state to a shutter insertion state.

  When forming a multilayer film with a curtain coating apparatus, as shown in FIG. 4, among the liquid films of a plurality of layers constituting the curtain 6, one layer is a wide layer 20 larger than the width of the plate, and the other layers are If the plate is a narrow layer 21 that overflows only a few tens of millimeters, most of the liquid film that overflows from the edge of the plate is a single layer of the wide layer 20, so this overflowing single layer portion is collected by the tray 15. This is preferred because layers of the same composition can be recycled into the liquid feed. That is, there is an advantage that the portion of the wide layer 20 that overflows from the edge of the plate can be recovered and reused. The layer in which the wide layer 20 and the narrow layer 21 are mixed is collected by the tray 16. In the example shown in FIG. 4, the paint discharged from the slits 2 a and 2 b constitutes the narrow layer 21, and the paint discharged from the slit 2 c constitutes the wide layer 20. Even in curtain coating that forms such a wide layer 20 and a narrow layer 21, the effect can be exhibited by applying the present invention.

  The experiment was performed using a slide curtain coater having a width of 1000 mm and two slits. The lower layer paint was a polyester paint and the upper layer was a polyester paint.

Example 1
The lower layer width was set to 1000 mm, the upper layer width was set to 800 mm, the lower layer curtain film thickness was set to 30 μm, and the upper layer curtain film thickness was set to 15 μm. Further, the distance from the curtain falling part of the slide coater to the steel plate was set to 150 mm. The moving speed of the steel sheet was changed in the range of 50 m / min to 70 m / min.

(Example 1-1)
When the lower end of the lifting device is connected to the center of the distance between the curtain falling part of the slide coater of the curtain guide and the steel sheet, and it is rolled up, it is confirmed that the curtain can be lifted without dropping the paint. did it. Also, when the curtain guide was lowered, the paint did not drop and was good.

  It should be noted that when the lower end of the lifting device is connected in the range of 20 mm above and below from the central part of the distance between the curtain falling part of the slide coater of the curtain guide and the steel plate, it is good without dropping off. there were.

(Example 1-2)
The lower end of the storage guide protruded 1 mm from the curtain falling part of the slide coater, the lower end of the lifting device was connected to the center of the distance between the curtain falling part of the slide coater of the curtain guide and the steel plate, and the curtain guide was raised. In this case, it was confirmed that the curtain could be lifted without dropping the paint. In addition, even after storage, the weight of the curtain guide was fixed to the lower part of the storage guide, so the weight could be stabilized.

(Example 1-3)
The lower end of the storage guide protrudes 1 mm from the curtain falling part of the slide coater, the curtain guide is installed at a position 3 mm from the outer end of the slide, and the center part of the distance between the curtain falling part of the curtain guide and the steel plate The lower end of the lifting device was connected to and the curtain guide was raised. In this case, it was confirmed that the curtain could be lifted without dropping the paint. In this case, the curtain edge was further stabilized, and the curtain edge breakage was eliminated.

  The same effect could be confirmed even when the experiment was performed by changing the installation position of the curtain guide to a position 5 mm from the outer end.

(Comparative Example 1-1)
The lower end of the lifting / lowering device is connected to a position shifted 40 mm downward from the center part of the distance between the curtain falling part of the slide coater of the curtain guide and the steel plate, and the rest of the conditions are the same as in Example 1-1. When it was rolled up, a drop of paint occurred.

(Comparative Example 1-2)
The lower end of the storage guide was projected 3 mm from the curtain falling part of the slide coater, and the remaining conditions were tested in the same manner as in Example 1-2. When the weight hits the lower end of the storage guide, paint leaked from the end. There has occurred.

(Comparative Example 1-3)
When the curtain guide was installed at a position 3 mm from the outer end of the slide and the remaining conditions were tested in the same manner as in Example 1-3, the end of the curtain was not frequently cut.

(Example 2)
As a result of conducting an experiment under the same conditions as in Examples 1-1 to 1-3, except that the lower layer width is 1000 mm and the upper layer width is 1000 mm. Good results similar to -3 were obtained.

  In addition, said Example is experimented about the effect of the structure of this invention, The structure of a coating material and the dimension of an apparatus can be applied similarly also in things other than an Example.

It is a figure which shows the curtain coating apparatus of this invention, (a) is a whole perspective view, (b) (c) is a fragmentary figure which shows a curtain guide. It is a figure which shows operation | movement of the curtain coating apparatus of this invention, (a) (c) (e) corresponds to a partial front view, (b) (d) (f) respond | corresponds to (a) (c) (e), respectively. FIG. It is a figure which shows operation | movement of the curtain coating apparatus of this invention, (a) (b) is a partial front view, (c) is the elements on larger scale which show a curtain guide attachment part. It is a figure which shows a curtain coating apparatus. It is a figure which shows the conventional curtain coating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Curtain coating apparatus 2 Discharge slit 3 Slide 4 Slide end 5 Curtain guide 5a Flexible member 5b Weight 6 Curtain 7 Plate (metal plate)
DESCRIPTION OF SYMBOLS 8 Lifting device 8a Wire part 8b Winding part 9 Shutter 10 Storage guide 11 Edge guide 12 Connection part 15 Tray 16 Tray 17 String 20 Wide layer 21 Narrow layer 22 Traveling direction

Claims (4)

  A curtain coating apparatus for freely dropping a liquid film curtain and coating a film on the surface of a traveling plate, comprising: a curtain guide for guiding both width ends of the free fall curtain; and a lifting device for raising and lowering the curtain guide. The guide is a suspension of flexible long material. The lower end of the lifting device located above the curtain guide is connected to the middle position of the curtain guide, and the curtain guide is raised upward by the lifting device. A curtain coating device, which is possible.   The curtain guide has a weight at its lower end, and the part of the lifting device connected to the middle position of the curtain guide is placed through the storage guide, and the lower end of the storage guide is below the curtain dropping part of the curtain coating device. The curtain coating apparatus according to claim 1, wherein the curtain coating apparatus protrudes.   The curtain coating device is a slide curtain coating device. The upper end of the curtain guide is suspended from the inner side in the width direction from both ends of the slide, and the storage guide is provided in contact with the outer side in the width direction at both ends of the slide. The curtain coating apparatus according to claim 2, wherein the apparatus is a curtain coating apparatus. In addition, it has a shutter that can be inserted between the curtain coating device and the plate to receive the coating liquid, and when the shutter is inserted below the curtain coating device, the curtain guide is raised upward by the lifting device The curtain coating apparatus according to any one of claims 1 to 3.

Images