JPH07265768A - Coating apparatus - Google Patents

Abstract

PURPOSE:To provide a coating apparatus which can continue a scraping operation well even if the frequency of adjusting the position and the angle of a scraping means and of changing the parts is lowered by producing the scraping means to scrape an excessive paint adhering to a flexible supporting body from a linear material curved to be an arc-like shape. CONSTITUTION:A paint 4 is supplied to a paint pan 5 through a paint supplying nozzle 7 and a gravure roll 1 is rotated. The paint 4 is picked up to the inside of a cell 6 of the gravure roll 1 and the quantity of the paint is regulated to be constant by a doctor blade 8. Further, the gravure roll 1 and a running flexible supporting body 2 are pressed and brought into contact with each other by a back up roll 3 and thus the paint 4 is transferred to the flexible supporting body 2. The excessive paint is scraped by a scraping 8 means 11, and the paint 4 is uniformized by a smoother 10. In a painting apparatus having a structure like that, the scraping means 11 is made of a linear material 12 curved to be an arcuate shape. The linear material 12 is formed so as to have an arcuate shape in which the diameter (e) in the sliding direction is made longer than the diameter (d) in the width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gravure roll type coating device, and more particularly to a scraping means for removing excess paint attached to both ends of a flexible support.

[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.

Among them, a typical direct gravure roll device will be described with reference to FIG. This coating apparatus includes a rotating gravure roll 1, a backup roll 3 for pressing a flexible support 2 onto the gravure roll 1, a paint pan 5 for storing a paint 4, and an excess paint 9 attached to the flexible support 2. The scraping means 111 and the like for removal are the main constituent elements.

A cell 6 is provided on the outer peripheral surface of the gravure roll 1.
Are engraved in a predetermined pattern. When the gravure roll 1 rotates in the direction a in the figure, the paint 4 supplied from the paint supply nozzle 7 to the paint pan 5 is sequentially picked up in the cell 6. . The paint 4 picked up is regulated by the doctor blade 8 to a fixed amount.

The paint 4 in the cell 6 which is regulated to a constant amount is b in the figure in synchronization with the gravure roll 1.
It is sandwiched between a backup roll 3 which rotates in the direction, and transferred and applied to the flexible support 2 which runs in the x direction in the figure.

At this time, due to the pressure of the backup roll 3, a surplus of the picked-up paint 4 overflows to both ends of the gravure roll 1 in the width direction, and a large amount is applied to both ends of the flexible support 2. The surplus paint 9 is attached. For this reason, a scraping means 111 is provided downstream of the crimping point between the gravure roll 1 and the flexible support 2 and upstream of the smoother 10 for uniformizing the paint 4, and scrapes the excess paint 9. The taking is taking place. As shown in the plan view of FIG. 2, the scraping means 111 is in sliding contact with the excess paint 9 at both ends of the flexible support 2.

In this scraping means 111, the effective coating film width is narrowed if it is scraped too much, and if the sliding contact state with the excess paint 9 is improper, the droplets of the scraped excess paint 9 will be removed. Since it scatters and adheres to a range where good coating is applied, optimization of the tip shape, material, slidable contact angle with the flexible support 2 and the like is being studied.

Usually, the scraping means 111 is composed of a plate-like sliding contact member 112 which is in sliding contact with the surplus paint 9 and a holder 113 which holds it, as shown in FIG. The sliding contact member 1
The material forming 12 is steel, stainless steel,
Examples include plastics. As the shape, as shown in FIG. 7, a substantially rectangular shape in a plane, a shape in which the tip portion T is notched obliquely as shown in FIG. 8, and similarly, the tip portion T is curved. And the like (not shown). The thickness of these sliding contact members 112 is 0.5 to 1.0 mm. In addition to the plate-like member as described above, as shown in FIG. 9, it is proposed to use a rolled film of polyethylene terephthalate or the like having a thickness of about 100 μm as the sliding contact member 112.

Then, the holder 113 is held by a jig 20 capable of changing the sliding contact position and the sliding contact angle of the sliding contact member 112, or the jig 20 is connected to an air cylinder 21 so that the front and rear (FIG. It has been devised so that it can be moved in the middle c direction).

[0010]

As described above, the scraped state of the excess paint 9 is optimized, but the excess paint 9 adheres and adheres to the sliding contact member 112 due to long-term use. When it comes, the scraping state changes. For example, when the scraping becomes insufficient, it becomes difficult to make the film thickness uniform by the smoother 10 due to the swelling of the excess paint 9, and as shown in FIG. The coating film 124 having a nonuniform film thickness is also formed on the portion. In this case, naturally, the shape of the winding roll after winding is also defective. Further, even if excessive scraping is performed, scraping becomes uneven, or the droplets of the excess paint 9 easily scatter again, the effective coating width is narrowed and the quality of the coating is deteriorated. I will let you.

In particular, when a magnetic tape is produced by applying a magnetic coating material as the coating material 4, it becomes impossible to use both end portions of the flexible support 2 due to the above-mentioned insufficient scraping or nonuniformity. However, the yield is deteriorated. Further, since the scattered droplets cause dropout, the above-described change with time in the scraped state is a serious problem.

In order to prevent the change in the scraping state as described above, the jig 20 and the air cylinder 21 are adjusted according to the adhesion of the excess paint 9 to sequentially change the position and angle of the sliding contact member 112. Alternatively, it is necessary to periodically replace the sliding contact member 112. However, such management leads to deterioration of productivity.

Therefore, the present invention has been proposed in view of the above-mentioned conventional circumstances, and adjusts the position and angle of the scraping means,
An object of the present invention is to provide a coating apparatus capable of maintaining a good scraped state for a long time even if the frequency of member replacement is significantly reduced.

[0014]

The present invention has been proposed in order to achieve the above-mentioned object, and at least a gravure roll for picking up a coating material in a cell provided on the surface, and running on the gravure roll. In a coating device comprising a backup roll for pressure-bonding the flexible support, and a scraping unit for removing excess paint adhering to both ends of the flexible support in the width direction, the scraping unit is circular. It is composed of a wire rod bent in an arc shape.

That is, the sliding contact member with the excess paint in the scraping means is an arc-shaped wire, and the portion bent in the arc shape scrapes off the excess paint as a free end. At this time, the bent shape of the wire may be an arc of a perfect circle, but in order to reduce the sliding contact range between the wire and the excess paint, the diameter in the sliding contact direction is smaller than the diameter in the width direction. It may be a long elliptical arc.

The cross-sectional diameter of the wire is preferably 0.3 to 1.5 mm, although it varies depending on the viscosity of the coating material and the like. If the wire is too thin, the excess paint scraped off passes through the inside of the arc of the wire and adheres to the flexible support again, so that the effect of the scraping means is small. On the other hand, if it is too thick, the excess paint tends to stagnate in the vicinity of the wire, the excess paint is likely to adhere to the wire, and the scraped-off excess paint droplets are easily scattered.

The wire is preferably made of stainless wire or piano wire which can secure desired strength and does not cause rust. Further, in order to prevent the paint from sticking to the surface of the wire, It is preferable to coat with a chlorinated ethylene resin. As the polyfluorinated ethylene-based resin, tetrafluoroethylene-hexafluoropropylene copolymer and perfluoroalkoxy resin are mainly suitable, but in addition, polytetrafluoroethylene and chlorotrifluoroethylene are also suitable. In addition, copolymers of vinyl fluoride, ethylene trifluoride, vinylidene fluoride, propylene hexafluoride and the like can be used. Further, polyethylene-based resin can also be used.

In order to coat the surface of the wire with the resin as described above, so-called baking coating may be performed by spraying a powder of the resin onto a heated wire.

[0019]

The scraping means in the coating apparatus according to the present invention is provided with a cross-sectional diameter and a circular arc shape of a wire rod which is a sliding contact member with excess paint,
By optimizing the installation position and angle, it is possible to scrape just enough. Further, since there is no resistance to the surplus paint inside the arc, the surplus paint can be dropped without being scattered, without being forced back.
Further, since the wire material has a small contact area with the excess paint and the excess paint is unlikely to stay near the wire material, the excess paint is unlikely to adhere to the surface of the wire material, and thus the scratched state is unlikely to change with time.

By bending the wire into an elliptic arc whose diameter in the sliding contact direction is longer than that in the width direction, the sliding contact range with the paint can be reduced and the scraping range can be reduced. Easy to regulate. Further, by optimizing the material of the wire material and the surface condition thereof, it is possible to further prevent the excess paint from further adhering to the surface of the wire material while ensuring desired strength.

Therefore, when the present invention is applied, it is possible to scrape off the excess paint adhered to the flexible support for a long time without excess or deficiency and without scattering droplets.

[0022]

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.

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 includes a rotating gravure roll 1, a backup roll 3 for pressing a flexible support 2 onto the gravure roll 1, a coating pan 5 for storing a coating 4, and a flexible support. Two
It is composed of a scraping means 11 and the like for removing the excess paint 9 adhered to.

The gravure roll 1 has a relatively low hardness of Fe.
And the like, and the cells 6 are engraved in a predetermined pattern as, for example, quadrangular pyramid-shaped recesses on the outer peripheral surface thereof. Therefore, when the gravure roll 1 rotates in the direction a in the figure, the paint 4 stored in the paint pan 5 is sequentially filled in the cells 6 on the surface of the gravure roll 1, and the paint 4 is continuously picked up. The picked-up paint 4 is regulated to a certain amount by a doctor blade 8 installed so that its tip contacts the outer peripheral surface of the gravure roll 1.

The backup roll 3 is a cylindrical roll made of an elastic material such as rubber. The backup roll 3 faces the outer peripheral surface of the gravure roll 1 with the flexible support 2 interposed therebetween. Is provided. The backup roll 3 rotates in the b direction in the figure in synchronization with the gravure roll 1. Therefore, by pressing the flexible support 2 onto the outer peripheral surface of the gravure roll 1, while transferring the paint 4 filled in the cells 6 of the gravure roll 1 onto the flexible support 2, The flexible support 2 can be sent out in the direction of arrow x in the figure.

The scraping means 11 plays a role of scraping off the excess paint 9 overflowing to both ends of the gravure roll 1 by the pressure of the backup roll 3, and the gravure roll 1 and the flexible support 2 are provided. In the width direction of the flexible support body 2 as shown in the plan view of FIG. 2, on the downstream side of the crimping point, and on the upstream side of the smoother 10 for uniformizing the coating material 4 on the flexible support body 2. It is arranged at both ends.

In the present invention, since the structure of the scraping means 11 is characteristic, it will be described below with reference to FIGS. 3 and 4. The scraping means 11 is composed of a wire 12 and a holder 13 for fixing the wire 12.

The wire 12 is formed by baking and adhering a perfluoroalkoxy resin on the surface of a stainless wire having a cross-sectional diameter of 0.3 to 1.5 mm.
It is bent into an elliptical arc shape having a diameter e of 15 to 20 mm in the sliding contact direction. Then, in order to hold the wire 12 in the holder 13, both end portions of the wire 12 are inserted and fixed in a plate-shaped support body 14, and the support body 14 is fixed by screws in the holder 13. As a result, both ends of the wire 12 are held by the holder 13, and the arc-shaped bent portions project as free ends.

When fixing the support 14 to the holder 13, if the screw is directly penetrated, the wire 12 may be distorted. Therefore, the screw penetrates the spacer having the same thickness as the support 14. It may be configured to intervene at the position where

The scraping means 11 as described above is installed at a position where the arc-shaped bent portion of the wire 12 comes into sliding contact with the surplus coating material 9 adhering to the flexible support 2, as shown in FIG. The holder 13 can be held by a jig 20 whose sliding contact position and sliding contact angle can be changed, or this jig 20 can be connected to an air cylinder 21 so that it can be moved forward and backward (direction c in the figure). It may be possible.

With such a structure, the arc portion of the wire rod 12 in the scraping means 11 comes into sliding contact with the surplus coating material 9 adhered on the flexible support body 2 as the flexible support body 2 travels, and the surplus coating material 9 is deposited. The paint 9 will be scraped off continuously.

Then, in order to carry out coating with the coating device as described above, the coating material 4 is supplied from the coating material supply nozzle 7 into the coating material pan 5, and the gravure roll 1 is rotated. As a result, the paint 4 is picked up in the cell 6 of the gravure roll 1, and the doctor blade 8 regulates this to a fixed amount. Then, the backup roll 3 press-bonds the gravure roll 1 and the traveling flexible support 2 to each other to transfer the coating material 4 to the flexible support 2. Then, the scraping means 11 may scrape off the excess paint 9, and then the smoother 10 may make the paint 4 uniform.

As a result, as shown in FIG. 5, it is possible to form a uniform coating film 24 on both sides of the flexible support 2 without swelling.

<Experiment 1> Here, there is a difference between the case where the coating is carried out by using the coating apparatus of the present invention having the above-mentioned structure and the case where the same coating is carried out by using the conventional coating apparatus. I decided to investigate.

A polyethylene terephthalate film was used as the flexible support 2, and the following magnetic paints (paints A and B) and back coat paint (paint C) were used as the paint 4.

Paint A (solid content: 37%, viscosity: 3500 cps) Magnetic powder: Co-adhered γ-Fe ₂ O ₃ binder: Vinyl chloride copolymer-polyurethane resin Solvent: Methyl ethyl ketone, toluene, cyclohexanone Additive : Lecithin

Paint B (solid content: 50%, viscosity: 7000 cps) Magnetic powder: Metal magnetic powder Binder: Vinyl chloride copolymer-polyurethane resin Solvent: Methyl ethyl ketone, toluene, cyclohexanone Additive: Lecithin

Paint C (solid content: 12%, viscosity: 100 cps) Magnetic powder: carbon binder: vinyl chloride copolymer-polyurethane resin solvent: methyl ethyl ketone, toluene, cyclohexanone additive: lecithin

Using the above-described coating apparatus of the present invention, the case of applying the above-mentioned paint A is Example 1, the case of similarly applying the paint B is Example 2, and the case of similarly applying the paint C. Was set as Example 3. In addition, the wire rod 12 in the coating device
The coating of Examples 4 to 6 was performed in the same manner except that the perfluoroalkoxy resin was not adhered to.

Further, as a conventional coating device, a scraping means in which a plate-like sliding contact member 112 shown in FIG. 7 is fixed by a holder 113 instead of the wire 12 and the support 14 shown in FIG. Comparative Examples 1 to 3 were applied in the same manner except that 111 was used.

In each of the examples and the comparative examples, the coating speed was 300 m / min, and the scattered state of the paint at the time of scraping, the scraping state, and the shape of the take-up roll were observed, respectively, ○, Δ, × Was evaluated. In addition, ○ is 10
Droplets do not scatter even after continuous coating of 10,000 m, good scraping is possible, and no swelling is seen on the winding roll. Δ indicates that droplets scatter in the middle of the scraping state. Deterioration occurs and swelling of the take-up roll is seen, but it can be dealt with by adjusting the position and angle of the scraping means or exchanging members, x indicates
It represents the case where there is severe deterioration and there is a problem with quality. Table 1 shows each evaluation result.

[0042]

[Table 1]

As can be seen from Table 1, the coatings according to Examples 1 to 6 are better than the coatings according to Comparative Examples 1 to 3 regardless of the viscosity of the coating material 4, in the scattered state of the coating material, the scraped state, and the shape of the winding roll. You can see that it is good. From this, it can be seen that it is very effective to form the sliding contact member of the scraping means with the excess paint 9 from the wire 12.

Further, comparing Examples 1 to 3 with Examples 4 to 6, the scraping state and the shape of the winding roll do not change even if the surface of the wire 12 is not coated with the perfluoroalkoxy resin. It can be seen that there is a difference in the paint scattering state. From this, in order to use for a long time, the surface of the wire 12 is coated with the polyfluorinated ethylene resin,
It can be seen that it is effective to prevent the excess paint 9 from sticking.

<Experiment 2> Next, the differences in the paint scattering state, the scraping state, and the winding roll shape depending on the cross-sectional diameter of the wire 12 were examined.

Sectional diameters of 0.1 mm, 0.3 mm, 1.0
The coating material A described above was applied by a coating device using the wire rods 12 having a size of 1.5 mm, 1.5 mm, and 2.0 mm, respectively.
In addition, each application was set to Examples 7-11 according to the cross-sectional diameter of the wire 12 used. When the coated state of each example was evaluated in the same manner as in Experiment 1, the results shown in Table 2 were obtained.

[0047]

[Table 2]

From Table 2, Examples 8 to 10 and Examples 7 and 1
Comparing with No. 1, if the cross-sectional diameter of the wire 12 is too small,
It can be seen that the scraped state and the shape of the winding roll are greatly deteriorated, and conversely, when the cross-sectional diameter is too large, the paint scattering state is greatly deteriorated. From this, the cross-sectional diameter of the wire 12 is 0.3 to
It was found that by controlling the thickness to 1.5 mm, the excess paint 9 can be scraped off sufficiently, and the excess paint 9 is less likely to stick and the paint scattering state can be kept good.

<Experiment 3> Next, the difference in the sliding contact range depending on the bent shape of the wire 12 was examined. Specifically, the relationship between the diameter d in the width direction and the diameter e in the sliding contact direction is d <e, d = e,
When coating was performed using bent wire rods 12 with d> e, it was measured how many mm the scraping width by these wire rods 12 and the width of the usable coating film (effective coating film width) would be. . The results are shown in Table 3.

[0050]

[Table 3]

From Table 3, when d <e, that is, when the diameter d in the width direction is smaller than the diameter e in the sliding contact direction, the wire 12 has an elliptical shape.
Since the sliding contact area with the paint can be reduced when the
It has been found that the scraping width is the smallest and the coating film 24 having a wide effective coating width can be formed.

Although the coating apparatus according to the present invention has been described above, the present invention is not limited to the above embodiments. For example, it is possible to install the above-described smoother in a reverse coating type coating device. Further, the field in which the coating apparatus of the present invention is used is not limited at all, since it is possible to uniformly coat a thin coating film, or to apply a magnetic coating in the manufacturing process of the magnetic recording medium, It is suitable for use when applying a back coat layer or a top coat layer. In that case, the magnetic powder, the resin binder, the back coat layer and the top coat layer, which are materials for the flexible support and the magnetic coating film, may be any conventionally known materials and are not limited in any way. .

[0053]

As is apparent from the above description, when coating is performed by using the coating device according to the present invention, even if the frequency of scraping means position and angle adjustment and member replacement are significantly reduced,
It is possible to stably form a good coating film that is free from swelling or adhesion of scattered paint over a long period of time.

Therefore, when the magnetic coating material is applied using this coating device, it is possible to form a magnetic layer which is excellent in magnetic characteristics and durability and has reduced dropout. Can be promoted.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a coating device.

FIG. 2 is a plan view of a part of the coating device as seen from the surface of the flexible support on which the paint is transferred.

FIG. 3 is a schematic diagram showing a scraping means applied in the coating apparatus of the present invention.

FIG. 4 is a plan view showing a wire rod that constitutes a scraping unit applied in the coating apparatus of the present invention.

FIG. 5 is a cross-sectional view showing a coating film formed by the coating apparatus of the present invention.

FIG. 6 is a schematic view showing a scraping means applied in a conventional coating device.

FIG. 7 is a plan view showing an example of a sliding contact member which constitutes a scraping means applied in a conventional coating device.

FIG. 8 is a plan view showing another example of a sliding contact member that constitutes a scraping unit applied in a conventional coating device.

FIG. 9 is a plan view showing still another example of the sliding contact member which constitutes the scraping means applied in the conventional coating device.

FIG. 10 is a cross-sectional view showing a coating film formed by a conventional coating device.

[Explanation of symbols]

 1 gravure roll 2 flexible support 3 backup roll 4 paint 5 paint pan 6 cell 7 paint supply nozzle 8 doctor blade 9 surplus paint 10 smoother 11 scraping means 12 wire rod 13 holder 14 support

Claims (5)

[Claims] 1. A gravure roll for picking up paint in a cell provided on the surface, a backup roll for pressing a flexible support running on the gravure roll under pressure, and a width direction of the flexible support. A coating device comprising a scraping means for removing excess paint adhering to both ends, wherein the scraping means comprises a wire rod bent in an arc shape. 2. The wire rod has an arc shape whose diameter in the sliding contact direction is longer than that in the width direction.
The coating device described. 3. The cross-sectional diameter of the wire is 0.3 to 1.5 m
It is m, The coating device of any one of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The coating device according to claim 1, wherein the wire is made of stainless wire or piano wire. 5. The coating apparatus according to claim 1, wherein the surface of the wire is covered with a polyfluorinated ethylene resin.