JPH06165963A - Coating applicator - Google Patents

Abstract

PURPOSE:To provide the coating applicator which supplies a sufficient amt. of a coating material onto a roll and can stably apply even a coating film of a small film thickness at a high speed by providing a rising wall near a coating material supplying port opened to a slit shape. CONSTITUTION:The coating applicator which transfers and applies the coating material onto a base traveling in contact with the gravure roll 1 meters the coating material continuously supplied by a nozzle 5 onto the surface of the gravure roll by means of a doctor blade 7. The nozzle 5 has the coating material supplying port 15 opened to the slit shape and is provided with the rising wall 16 near the coating material supplying port. The coating material failing to stick to the gravure roll 1 is dammed up by the rising wall 16, by which the coating material is stored into the space between the wall and the outer peripheral surface of the gravure roll. As a result, the distance and the time at which the gravure roll 1 comes into contact with the coating material increases and the always sufficient amt. of the coating material is therefore supplied onto the roll and the generation of uneven application is obviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for coating a thin coating film at high speed and stably.

[0002]

2. Description of the Related Art Conventionally, a roll-type coating device such as a gravure roll system or a kneader roll system has been widely used for coating a magnetic paint or a back coat agent in the manufacture of a magnetic recording medium.

For example, a direct gravure roll device picks up a coating material by a cell pattern engraved on the surface of the roll, deposits a limited amount of the coating material on the support by the doctor blade, and then rotates the gravure roll. The coating is continuously applied by running the support between the backup roll and the backup roll.

However, since the above-mentioned doctor blade is made of stainless steel or the like having a high rigidity in order to firmly scrape off the paint on the surface of the gravure roll, it has a drawback that it is worn when contacting the gravure roll and is inferior in durability. is there.

Further, in the above apparatus, since the coating material is stored in the coating liquid pan, the surface is always in contact with air. Therefore, with the passage of time, the solvent gradually evaporates on the surface, the composition and viscosity change, and it is difficult to form a coating film having a stable coating thickness and characteristics over a long period of time. . Furthermore, when trying to increase the peripheral speed of the gravure roll in order to increase the coating speed, the rotation of the gravure roll causes the coating liquid surface to turbulently generate bubbles, causing the coating material to scatter. Cannot be improved sufficiently.

On the other hand, the coating by the kneader roll method can stably supply the coating material, but the coating speed is still limited. Further, when the kneader roll is deteriorated, there is a problem that the thickness of the coating film becomes uneven.

[0007]

Since the above-mentioned coating method cannot perform stable coating at a high coating speed, the coating is performed by using a nozzle on the gravure roll surface as a method for supplying the coating to the roll. It is possible. Unlike the direct gravure roll method, the paint supply by the nozzle does not contact the air with air more than necessary, so there is no change in composition and viscosity with time, and there is no risk of deterioration like the kneader roll method. On the other hand, there is an advantage, but when high speed coating of 100 m / min or more is performed, there is also a problem that paint is cut off and a portion which is not coated is formed.

Even if the coating material is supplied to the roll by the nozzle in a non-contact manner, as described above, if the doctor blade is made of metal, abrasion still occurs. Therefore, it can be considered that the doctor blade is made of plastic. However, although the plastic blade does not wear with the gravure roll and can be used for a long period of time, its rigidity is low, and when scraping the paint on the surface of the gravure roll, unevenness tends to occur, resulting in uneven thickness. Therefore, it has been unsuitable for forming a thin coating film at a high speed.

Therefore, the present invention has been proposed in view of the above-mentioned conventional circumstances, and provides a coating apparatus in which a gravure roll or a doctor blade is less worn and a thin coating film can be stably coated at high speed. With the goal.

[0010]

In order to achieve the above-mentioned object, the coating apparatus of the present invention is improved in the nozzle for supplying the paint and the doctor blade for measuring the paint. It is what

That is, the present invention provides the coating apparatus in which the coating material continuously supplied from the nozzle to the surface of the gravure roll is measured by the doctor blade and transfer-coated on the support running in contact with the gravure roll. The nozzle is characterized in that it has a paint supply port opened like a slit, and a rising wall is provided near the paint supply port to form a paint reservoir.

Further, the present invention is a coating apparatus in which a coating material continuously supplied to a surface of a gravure roll by a nozzle is measured by a doctor blade and transfer-coated on a support running in contact with the gravure roll. The sliding contact portion with the gravure roll is made of plastic and has a strain of 30 μm or less.

The plastic plate is characterized in that it is supported by being sandwiched by pressing plates from above and below.

Further, in the coating apparatus of the present invention, the support member travels while receiving a predetermined tension by the pair of rolls,
It is preferable that the roll is in contact with the gravure roll in the middle part between these rolls. At this time, the gravure roll preferably has a diameter of 50 mm or less.

[0015]

In the coating apparatus of the present invention, the nozzle is provided with the rising wall, so that the paint that has not adhered to the gravure roll is dammed against this and the space between the outer peripheral surface of the gravure roll and the rising wall is described above. Paint is stored.
This increases the distance and time for the gravure roll to come into contact with the coating material, so that a sufficient amount of the coating material is always supplied onto the roll and uneven coating does not occur.

Further, the doctor blade of the coating apparatus of the present invention does not wear the gravure roll because the portion which is in sliding contact with the gravure roll is the plastic plate. Furthermore, the parts other than the sliding contact part are sandwiched by the material with high rigidity, and the distortion of the protruding plastic part is 30μ.
Since the thickness is m or less, unevenness in the thickness of the paint does not occur.

Further, when the reverse coating method is applied and the roll diameter of the gravure roll is 50 mm or less, the contact area between the support and the peripheral surface of the coating roll is reduced, and the coating amount is controlled, so that the film is formed. 30 thin coating
It can be formed uniformly and stably even at a high speed coating of 0 m / min or more.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

Example 1 First, the structure of an example of a coating apparatus to which the present invention is applied will be described. As shown in FIG. 1, this coating apparatus 10 supplies a gravure roll 1 having a cell pattern engraved on its surface, a nozzle 5 having a slit-shaped coating material supply port, and a nozzle 5 to the gravure roll 1 surface. It comprises a doctor blade 7 for controlling the amount of the applied paint, a backup roll 2 for pressing a support (hereinafter referred to as a base film) 4 to the gravure roll 1, and the like.

In the above apparatus, the paint is applied to the nozzle 5
And is filled in the cell groove on the surface of the gravure roll 1. After that, the amount is limited to a certain amount by the doctor blade 7 and adheres to the running base film. And gravure roll 1 and backup roll 3
It is crimped by being sandwiched between.

Here, the gravure roll 1 has the base film 4 coated with the paint filled in the cell grooves engraved on the surface.
It is for transferring on top. The gravure roll 1 is composed of a cylindrical roll made of Fe or the like having a relatively low hardness, and a helical annular recess is formed on the outer peripheral surface. Therefore, the protrusion between the recesses is, so to speak, a multiple thread screw. It is carved. Therefore, by rotating the gravure roll 1 in the direction indicated by the arrow in the figure, the paint filled in the cell grooves of the gravure roll 1 can be continuously supplied to the paint applying section.

The width of the gravure roll 1 is larger than that of the base film 4, and the width of the cell groove arrangement portion is smaller than that of the base film 4.

The nozzle 5 supplies the paint to the gravure roll 1. In the present invention, the nozzle 5 is provided with a rising wall near the paint supply port to form a paint reservoir. Is a major feature.

As shown in FIGS. 2 and 3, the nozzle 5 is
A main body 11 in which a paint supply port 15 is arranged so as to face the gravure roll 1, a paint supply pipe 13 for feeding the paint to the main body 11, and a rising wall 1 for damming the paint.
6 etc.

There is a void 12 inside the main body 11 of the nozzle 5, and this void 12 is for pooling the paint 6 supplied from the paint supply pipe 13 and forcing it out evenly in the width direction of the gravure roll 1. The paint supply port 15 is formed by opening the side facing the gravure roll 1 with a predetermined slit width s. On the other hand, there is a hole 14 at the rear of the space 12, and the paint supply pipe 1 is provided through this hole 14.
The paint 6 is supplied to the space 12 from the space 3. A rising wall 16 is provided near the paint supply port 15.
Is provided, and the space between the rising wall 16 and the outer peripheral surface of the gravure roll serves as a paint reservoir 17.

Since the rising wall 16 is provided in the vicinity of the paint supply port 15 in this manner, the paint 6 that has not adhered to the gravure roll 1 is blocked so as not to flow and a paint pool 17 is formed. When the coating material 6 extruded from the nozzle 5 is attached to the gravure roll 1, the coating material is liable to run out, especially when the coating speed is high, resulting in coating loss. However, if the paint reservoir 17 is provided above the paint supply port 15 and the paint 6 stays in the vicinity of the paint supply port 15, the gravure roll 1 is in contact with the paint 6 for a long time, and therefore, it is always sufficient. The amount of the coating material 6 is supplied onto the gravure roll 1.

The height of the rising wall 16 for forming the paint reservoir 17 is preferably 10 mm or more. If it is too low, the distance and time during which the gravure roll 1 comes into contact with the coating material 6 are short, and the effect of providing the coating material reservoir 17 becomes small.

The distance between the paint supply port 15 of the nozzle 5 and the facing gravure roll 1 is preferably 0.5 mm or less. If it is farther than this, the paint 6 cannot be sufficiently adhered to the gravure roll 1, and the paint 6 that has not adhered falls to the bottom because the paint 6 does not adhere.
The effect of setting 7 is not exhibited.

Further, the nozzle 5 provided with the coating material reservoir 17 as described above can stably supply the coating material even at high speed coating, and when performing high speed coating at 300 m / min or more,
The coating material may be supplied to the nozzle 5 at a flow rate of 1 to 3 l / min.

By the way, although the amount of the coating material 6 supplied to the gravure roll 1 as described above is limited by the doctor blade 7, this doctor blade 7 is also characteristic in the present invention, and will be described below. .

First, as shown in FIG. 4, the doctor blade 7 has a plastic plate 21 which directly slides in contact with the gravure roll 1, upper and lower pressing plates 22 and 23 for sandwiching the plastic plate 21, and further, one end of which is sandwiched from above and below for fixed support. It comprises holders 25, 26 and the like. Then, the screws 27 sequentially pass through the holder upper part 25, the pressing plate upper part 22, the spacer 24 having the same thickness as the plastic plate 21, and the pressing plate lower part 23, and then reach the holder lower part 26, whereby these are integrated. There is.

Here, the screw 2 is directly attached to the plastic plate 21.
When 7 is penetrated, distortion is caused and it is inconvenient to evenly scrape the plastic plate 2.
A spacer 24 having the same thickness as 1 is interposed between the upper and lower pressing plates 22 and 23 at a position where the screw 27 penetrates. As shown in FIG. 5, when the screws are screwed in several positions in the width direction (tighten evenly using a torque wrench), the force with which the pressing plates 22 and 23 sandwich the plastic plate 21 can be made uniform in the width direction.

At the end opposite to the one fixed by the holders 25 and 26, the tip of the plastic plate 21 projects 4 mm (± 2 mm) from the upper pressing plate 22. Further, the lower holding plate 23 is retracted from the upper holding plate 22 by about 3 mm so that the stress does not escape upward when a force is applied to the doctor blade 7.

The upper and lower pressing plates 22 and 23 are made of hardened steel having a Rockwell hardness of 55 ° or more and a thickness of 2 mm or more to have a plane accuracy of 15 μm or less. Therefore, the distortion of the protruding plastic plate 21 is also controlled to 30 μm or less. In this embodiment, the plastic plate 21 has a tip portion of 200 μm,
In the other parts, the one manufactured by Esterrum Co. having a thickness of 600 μm was used.

In the doctor blade 7 described above, the plastic plate 21 protruding from the pressing plates 22 and 23 is supported so that the tip thereof contacts the gravure roll 1. Therefore, the coating material 6 supplied onto the gravure roll 1 by the nozzle 5 is limited and made uniform by the gravure roll 1 rotating and sliding contact with the tip of the plastic plate 21.

The above is the configuration of the coating apparatus of the present embodiment,
It is performed by the system as shown in FIG. The nozzle 5 provided with the rising wall 16 is installed on a support base 42 in which a pump for pushing out the paint supply pipe and the paint is housed, and by setting the angle of the support base 42, the nozzle 5 and the gravure roll 1 are desired. Are facing each other. Further, the doctor blade 5 in which the plastic plate 21 is sandwiched between the pressing plates 22 and 23 is connected to the support body 41 whose angle can be freely set, so that the paint on the gravure roll 1 can be appropriately measured. It is arranged as follows.

Here, it was decided to actually perform coating with the coating apparatus of the present embodiment and the conventional coating apparatus for comparison. First, the following results were obtained by comparing the flow of the paint between the coating device of the present embodiment in which the paint reservoir is provided in the nozzle and the coating device of the same configuration except that the paint reservoir is not provided. .

When observing the supply of the paint by the nozzle not provided with the paint reservoir, the paint extruded from the paint supply port and unable to adhere to the gravure roll flowed to the upper surface or the lower part of the nozzle. On the other hand, in the case where the paint puddle 17 is provided, of the paint supplied from the paint supply port 13 to the gravure roll 1, the part not adhered to the roll 1 is accumulated in the paint puddle 17 and the paint puddle 1
It was observed that the coating material 6 flowed out to the rear or both ends of the nozzle 5 only after exceeding the capacity of 7.

Further, when the base film coated with both nozzles was examined, there was paint loss in the one coated with the former nozzle, but there was paint loss in the one coated with the latter nozzle. I couldn't find the blank.

Next, it was decided to examine whether there is a difference in the life of the gravure roll between the case of using the doctor blade as in this embodiment and the case of using the conventional stainless steel doctor blade. Using the doctor blade of the present invention as the coating device of Example 1 and the one using the conventional doctor blade as the coating device of Comparative Example 1, actual coating was performed, and the total coating length until the gravure roll was replaced was changed. Table 1 compares the results with the reason for replacing the gravure roll.
Shown in.

[0041]

[Table 1]

In the coating apparatus using the doctor blade of the present invention, the gravure roll was observed under a microscope of 400 times. As a result, neither scratch nor abrasion was confirmed, and it was found that there is no need to replace it unless it is intentionally scratched. It was

From the above results, it was found that a high quality coating film can be coated at high speed and productivity is high when the coating apparatus of the present invention is used.

Embodiment 2 Next, the structure of another example of the coating apparatus to which the present invention is applied will be described. As shown in FIG. 6, the coating device 40 includes a gravure roll 31 having a cell pattern engraved on the surface thereof, and a predetermined tension applied to the base film 34 to press the base film 34 onto the gravure roll 31. Guide roll 32, a second guide roll 33, a nozzle 35 having a slit-shaped coating supply port, and a doctor blade for controlling the amount of the coating 36 sprayed from the nozzle 35 and supplied to the surface of the gravure roll 31. It is composed of 37.

The first guide roll 32 and the second guide roll 33 are arranged in parallel at a predetermined interval on the upper left and right sides in the figure and have a width substantially the same as that of the base film 34. It is designed to rotate in the same direction as indicated by the middle arrow a. The base film 34 runs in the direction of the arrow b in the figure along the peripheral surfaces of the guide rolls 32 and 33 while receiving a predetermined tension from the guide rolls 32 and 33. Further, the base film 34 has a diameter smaller than that of the guide rolls 32 and 33 so as to push the base film 34 upward in the figure in the middle of traveling from the first guide roll 32 to the second guide roll 33. The gravure roll 1 having a width larger than that of the base film 34 (provided that the width of the coating application portion, that is, the portion where the cell grooves are disposed is smaller than the width of the base film 34) is disposed. Has been done.

The nozzle 35 and the doctor blade 37
Is the same as that of the first embodiment.

By using the above-mentioned apparatus, coating called a reverse coating method is possible, and it becomes possible to stably form a coating film having a small film thickness. In this apparatus, the long-axis base films run on the peripheral surfaces of two rolls arranged in parallel with a predetermined space and rotating in the same direction while receiving a predetermined tension. At this time, the gravure roll is arranged so as to push up the traveling base film in the middle of traveling of the base film from the first guide roll to the second guide roll. Since a predetermined tension is applied from the base film, the base film is pressed against the gravure roll.

The above-mentioned reverse coating method is suitable for forming a coating film having a thin film thickness, and the thinner the coating film is, the smaller the gravure roll diameter is used. This is because when the roll has a small diameter, the contact area between the base film and the peripheral surface of the coating roll becomes small and the coating amount is controlled, so that the accuracy of the film thickness can be improved.

Even when the coating device 40 of this embodiment is used, the same effect as that of the first embodiment can be obtained, but in this embodiment, the diameter of the gravure roll is reduced to 50 mm or less so that the diameter is about 0.3 μm. It becomes suitable for forming a coating film.
Further, it becomes possible to perform uniform and stable coating even at high speed coating of 300 m / min or more. Such a coating device is also characterized in that it is more compact than a kneader roll system or the like.

Further, in the coating device 40, the guide rolls 32 and 33 are rotated in the opposite direction to those described above to reverse the traveling direction of the base film 34 (the positions of the nozzle 35 and the doctor blade 37). And the rotation direction of the gravure roll 31 is the same), and the coating can be performed in the same manner.

The field in which the coating apparatus of the present invention as described above is used is not limited in any way, but since a thin coating film can be uniformly and stably coated, it is a manufacturing process of a magnetic recording medium. It is suitable for use when applying a magnetic paint or applying a back coat layer or a top coat layer. In that case, conventionally known materials can be used for the magnetic powder constituting the non-magnetic support and the magnetic coating film, the resin binder, the material of the back coat layer and the top coat layer,
It is not limited in any way.

[0052]

[Effect] As is apparent from the above description, the coating apparatus of the present invention can stably supply a sufficient amount of coating material onto the gravure roll, and evenly limit the coating material to perform coating. be able to. Therefore, a coating film having a small film thickness can be uniformly and stably formed even in high-speed coating.

Further, the gravure roll is not worn and the productivity is high.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a coating apparatus of the present invention.

FIG. 2 is a sectional view schematically showing the configuration of a nozzle.

FIG. 3 is a perspective view schematically showing the configuration of a nozzle.

FIG. 4 is a sectional view schematically showing the configuration of a doctor blade.

FIG. 5 is a perspective view schematically showing the configuration of a doctor blade.

FIG. 6 is a schematic view showing another configuration example of the coating apparatus of the present invention.

FIG. 7 is a schematic diagram showing an overall image of a coating apparatus of the present invention.

[Explanation of symbols]

 1 ... Gravure roll 2 ... Backup roll 4 ... Base film 5 ... Nozzle 6 ... Paint 7 ... Doctor blade 8 ... Paint coating section 10 ... Coating device 11 ...・ Main body 12 ・ ・ ・ Void portion 13 ・ ・ ・ Paint supply pipe 14 ・ ・ ・ Hole portion 15 ・ ・ ・ Paint supply port 16 ・ ・ ・ Standing wall 17 ・ ・ ・ Paint reservoir 21 ・ ・ ・ Plastic plate 22, 23 ・..Holding plates 24 ... Spacers 25, 26 ... Holders 27 ... Screws

Claims (5)

[Claims] 1. A coating device in which a coating material continuously supplied to a surface of a gravure roll by a nozzle is measured by a doctor blade and transfer-coated on a support running in contact with the gravure roll, wherein the nozzle has a slit shape. An applicator having a paint supply port opened to the inside, and a rising wall is provided near the paint supply port to form a paint reservoir. 2. A coating device in which a coating material continuously supplied from a nozzle to the surface of a gravure roll is measured by a doctor blade and transferred and applied onto a support that runs in contact with the gravure roll, wherein the gravure of the doctor blade is used. An applicator characterized in that a sliding contact portion with a roll is made of a plastic plate and its distortion is 30 μm or less. 3. The coating apparatus according to claim 2, wherein the plastic plate is supported by being sandwiched by pressing plates from above and below. 4. The coating apparatus according to claim 2, wherein the support member travels while receiving a predetermined tension by the pair of rolls, and is in contact with the gravure roll at a midpoint between the rolls. 5. The coating apparatus according to claim 4, wherein the gravure roll has a diameter of 50 mm or less.