JPH05212336A - Coating device - Google Patents

Abstract

PURPOSE:To make the width of magnetic paint within a slit constant by arranging a plate-shaped filter member to the midway part of the slit of a die having a paint sump and extruding the magnetic paint through the filter member to apply the same to a non-magnetic support. CONSTITUTION:In an extrusion type coating device, the pressure distribution in the lateral direction of a slit 5 of the magnetic paint 3 supplied into the slit 5 from a paint sump 2 is uniformized by the filter member 9 arranged to the midway part of the slit 5 and the stagnation of the paint is eliminated and the pressure distribution in the lateral direction of the slit 5 of the magnetic paint 3 in the slit 5 becomes uniform. As a result, uniform coating thickness distribution is obtained on a non-magnetic support 8 and no stripe is generated on the surface of a paint film. Since the filter member 9 is movable up and down, not only a part of the plate-shaped filter member 9 but also the entire surface thereof can be used and, even at the time of the replacement of the filter member 9, it is unnecessary to disassemble the die 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion type coating apparatus called a die coater.

[0002]

2. Description of the Related Art Conventionally, as a coating method of a magnetic coating material for manufacturing a coating type magnetic recording medium, a roll coating method using a roll is mainly used as represented by a gravure roll method and a reverse roll method. Is becoming However, in these roll coating methods, output fluctuations due to coating thickness unevenness due to poor transfer of paint from the roll to the base film, which is a non-magnetic support, drop-out due to paint scattering, and excess supply paint returned to the mixing process. There is a problem such as deterioration of the paint quality due to this, and these problems tend to become more prominent especially as the coating speed increases.

In recent years, an extrusion (die) method has been attracting attention as a new coating method capable of solving these problems, and it has already been partially put into practical use. The extrusion method has a wide slit at the tip and uses a die with a doctor edge near the tip,
It is a method in which a coating material continuously extruded toward the surface of a moving support is applied onto the support with a uniform thickness by the doctor edge, and has been used in the fields of photographic film and photographic paper. It is a thing.

[0004]

By the way, in the extrusion type coating apparatus, the coating material is supplied to a coating material reservoir of a die called a pocket, and is extruded from this into a slit with a predetermined pressure. The pocket is formed on the back side of the slit as a cylindrical space having a length substantially equal to the width of the slit.

At this time, in order to supply the paint to the pocket, it is general to supply the paint from the central portion of the pocket or from both sides of the pocket. In any case, the paint stays in the pocket. Is likely to occur, and pressure distribution occurs in the width direction of the slit, which causes uneven coating and surface streaks.

Therefore, as one method for solving this, it has been proposed to use the flow analysis of the paint in the die to make the pocket shape along the analysis streamline. However, this method requires advanced flow analysis technology and processing technology, and since the flow shape differs depending on the viscosity characteristics of the paint, the type of paint that can accept one pocket shape is greatly limited, Practicality is not good.

Alternatively, as described in Japanese Examined Patent Publication No. 60-53674, etc., the paint is supplied to the pocket of the die in an amount larger than the coating amount, and the excess paint is caused to flow out from a position farthest from the supply position to cause unevenness in the paint. Attempts have been made to eliminate this. However, even with this method, a coating thickness distribution occurs along with the pressure distribution along the width direction, and when attempting to reuse the excess paint that has flowed out from the die, the paint quality deteriorates and drop out increases. , It will adversely affect the coating quality.

Further, an attempt has been made to insert a cylindrical or plate-shaped filter member into the pocket of the die and supply paint to the slit through the filter member to eliminate the pressure distribution in the width direction of the slit. ing. That is, a cylindrical filtering member having an outer size smaller than the inner diameter of the pocket is arranged in the cylindrical pocket, and the paint is supplied to the pocket via the filtering member. Alternatively, a plate-shaped filter member is arranged at the paint supply port from the pocket to the slit, and the paint is supplied to the slit via this filter member.

However, in the former method, since the filtration area of the paint is large and the area of the filtered paint on the outflow side is also large, the pressure loss is small and the rectification effect is low. Further, since the die needs to be disassembled when the filter member is replaced, and it takes time to replace the die, the productivity is low. Further, in the latter method, since the filtering member is arranged at the paint supply port from the pocket to the slit, the filtration area of the paint is relatively small, and the area on the outflow side of the filtered paint is also relatively small. Although the loss is high and the rectification effect is high, pressure is applied, so that the filter member is more likely to be clogged than the former. At this time, the clogging is a part of the plate-shaped filter member, and although the other part is still usable, the filter member is moved to use the other part because the installation location is in the pocket. Since this is not possible, it is necessary to replace the filtration member, and the loss of the filtration member is large. Furthermore, since the die must be disassembled when the filter member is replaced, and the replacement takes time, the productivity is low.

Therefore, the present invention has been proposed in view of the above-mentioned conventional circumstances, and it is possible to eliminate the pressure distribution in the slit, and obtain a uniform coating thickness and a smooth surface property without streaks or the like. An object of the present invention is to provide a coating device that can be used. Another object of the present invention is to provide a coating apparatus that does not require a special flow analysis technique and can simplify the shape of a paint pool or the like.

Further, according to the present invention, the entire amount of the coating material supplied to the die can be applied, and the coating material can be applied with little loss without degrading the coating material quality, the loss of the filtering member can be reduced, and the filtering member can be replaced. It is an object of the present invention to provide a highly productive coating device that can be easily maintained.

[0012]

In order to achieve the above-mentioned object, a coating apparatus of the present invention comprises a die having a paint reservoir to which paint is supplied, and a non-magnetic support which continuously runs. In an extrusion type coating device that applies coating while extruding paint from a slit provided at the tip of the die above, a plate-like filter member that is vertically movable is arranged in the middle of the slit of the die, and the filtration is performed. The coating material is applied onto the non-magnetic support through the member.

[0013]

In the coating apparatus of the present invention, the pressure distribution in the slit width direction of the coating material supplied from the coating material reservoir into the slit is rectified by the filtering member disposed in the middle of the slit, and the retention is eliminated. , The pressure distribution of the paint in the slit in the slit width direction becomes uniform.

As a result, a uniform coating thickness distribution can be obtained, and no streak or the like is generated on the coating film surface. Further, since the filter member is movable in the vertical direction, it is possible to use not only a part of the plate-shaped filter member but also the entire surface thereof. Further, it is not necessary to disassemble the die even when the filter member is replaced.

[0015]

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. The coating apparatus of this embodiment is used for coating a magnetic coating material in a manufacturing process of a coating type magnetic recording medium, and as shown in FIG. 1, a pocket of a die (extruder) 1 (coating material pool).
The magnetic paint 3 is supplied into the inside 2 and this is supplied to the slit 5. Then, the element box 4 configured such that the plate element 4a can be installed inside the slit 5
Are arranged. Since the slit 22 communicating with the slit 5 is formed in the element box 4,
The magnetic paint 3 passes through a plate element 4a (three sheets in this embodiment) which is a filtering member, is extruded from the tip of the slit 5, and is applied onto a base film 8 which is run through guide rolls 6, 7 and the like. ..

As shown in FIG. 2, the die 1 is made of a metal block having a substantially rectangular parallelepiped having a predetermined width.
The tip portion is shaved obliquely to form a so-called wedge shape, and the tip surface 1a is made of cemented carbide or the like and has a doctor edge. Slits 5 are formed in the die 1 so as to face the tip end surface 1a of the die 1 in accordance with the coating width. The slits 5 serve as gaps for extruding the magnetic paint, and are usually 0. 01-2m
It is a very narrow gap of about m.

On the back side of the slit 5, a pocket 2 communicating with the slit 5 is formed as an orifice-shaped space having a length substantially equal to the width of the slit 5.
At both ends of the pocket 2, paint supply ports 10 and 11 having an inner diameter smaller than that of the pocket 2 are provided so as to open on both side surfaces 1b and 1c of the die 1, from which magnetic paint is applied. It is designed to be supplied in the pocket 2. Therefore, the pocket 2 serves as a space for receiving the paint pressure-fed from the paint supply device and has a function of an accumulator.

Further, in this embodiment, if necessary, a circular tubular filter member 9 is arranged in the pocket 2 of the die 1 having the above-mentioned structure. The filtering member 9 is a tubular body having an outer diameter smaller than the inner diameter of the pocket 2 and an inner diameter larger than the outer diameters of the paint supply ports 10 and 11. Supply port 10,1
It is installed in the pocket 2 so that 1 is located.

Therefore, the magnetic paint supplied from the paint supply ports 10 and 11 first enters the space inside the filter member 9, then oozes from the outer surface of the filter member 9 into the pocket 2, and enters the slit 5. Will be pushed out.
At this time, the widthwise flow of the supplied magnetic paint slit 5 is rectified to some extent by passing through the filter member 9.

The filtering member 9 may be made of any material as long as it has a certain degree of pressure loss, but it is necessary that it has fine pores that allow the magnetic powder contained in the magnetic paint to pass through. Therefore, in addition to a metal sintered filter (for example, a stainless sintered filter), a ceramics filter, etc., a fibrous filter, various foams, etc. can be used.

Further, in this embodiment, the element box 4 in which the plate elements 4a (three in this embodiment) can be installed, constitutes the flow path of the magnetic paint 3, and the slit 5 is formed. It is located midway. The element box 4 is a unit box that can be attached and detached from the side surface 1b or 1c of the die 1 (in this embodiment, it is attached and detached from the side 1b), and has a rectangular parallelepiped shape having substantially the same width as the die 1. It is a thing. Further, the element box 4 is formed with a slit 22 communicating with the slit 5.

Therefore, the paint supplied from the pocket 2 passes through the plate element 4a, which is a plate-like filtering member of the element box 4, is pushed out from the tip of the slit 5, and is applied to the running base film. The state of the flow of the magnetic paint at this time is shown in FIG. As shown in the figure,
The plate element 4a is installed so as to be orthogonal to the slit 22. At this time, since the area of the paint outflow side 22b is smaller than the area of the paint supply side 22a, the flow of the magnetic paint shown by the arrow A in the drawing is significantly narrowed, and the plate element 4a performs filtration, The pressure loss becomes very large and rectification is performed. Therefore, the pressure distribution of the magnetic paint in the width direction of the slit 5 is eliminated, a uniform coating thickness distribution is obtained at the time of coating, and streaks and the like do not occur on the coating film surface.

The structure of the element box at this time is shown in detail in FIG. As described above, the slit 22 is formed so as to penetrate from the side surface 4i to the side surface 4f of the element box 4 having a width substantially the same as that of the die 1, and the slit 22 communicates with the slit 5 of the die. The gap of the slit 22 is gradually reduced from the side surface 4i toward the side surface 4f. Further, an element insertion groove 4b is formed in the element box 4 so as to be orthogonal to the slit 22, and the plate element 4a is inserted into this element insertion groove 4b. Further, on the bottom surface 4h of the element box 4, an adjusting screw 12 not shown in the drawing is provided.
An insertion opening is formed. Therefore, when the plate element 4a is attached to the element box 4, the plate element 4a is inserted into the element insertion groove 4b and is supported by the adjustment screw 12 inserted into the bottom surface 4h. At this time, the O-ring 13 is disposed on the adjusting screw to prevent the paint passing through the plate element 4a from leaking.

Further, a recess 4d is formed in the upper surface 4c of the element box 4 as a space for accommodating the upper portion of the plate element 4a when the plate element 4a is moved in the vertical direction. That is, the open portion of the element insertion groove 4b is formed so as to face the bottom surface 4e of the recess 4d.

Therefore, FIG. 5 shows a sectional view of the plate element 4a mounted on the element box 4. As shown in FIG. As described above, the plate element 4a is inserted into the element insertion groove 4b, and is supported by the adjusting screw 12 provided with the O-ring 13 from the bottom surface 4h. Since the element box 4 has the above-described configuration, the plate element 4a can be moved in the vertical direction by adjusting the adjusting screw 12. Therefore, the plate element 4a
Even if a high pressure is applied to a part of the plate to cause clogging or the like, the plate element 4a is moved in the vertical direction,
By using the other part of a, it is possible to extend the usable period of the plate element 4a which is the plate-like filtering member.

Regarding the size of the plate element 4a,
As shown in FIG. 4, the length L ₁ of _one side is substantially the same as the width of the slit 5, and the length L ₂ of the other side is the slit 5.
It is longer than the gap length. Further, the material of the plate element may be any material as long as it has a pressure loss to some extent, but it is necessary to have fine holes to the extent that the magnetic powder contained in the magnetic paint can be transmitted.

Therefore, in addition to a metal sintered filter (for example, a stainless sintered filter), a ceramics filter, etc., a fibrous filter or various foams can be used.

Further, the outer shape of the element box may be determined according to the die, and the inner shape, for example, the paint path, the installation position and the number and shape of the plate elements, and the specifications may be decided according to the properties of the magnetic paint to be used. Good.

As shown in FIG. 2, the element box 4 is a unit box that can be attached and detached from the die side surface 1b. Here, an enlarged view of the attachment and detachment portion of the element box 4 is shown in FIG. As shown in FIG. 6, the side surface 1b of the die 1 may be provided with holes 14 in accordance with the size of the element box 4, and the element box 4 may be slid to be attached and detached. Further, when the element box 4 is attached or detached, if the handle 15 is attached to the side surface 4g of the element box 4 facing the side surface 1b of the die 1 for attachment and detachment, the attachment and detachment can be performed more easily. Also,
The side surface 1b of the die 1 has a larger area than the hole portion 14,
The recess 16 having a depth reaching the slit forming position of the die 1
When the element box 4 is mounted on the die 1, the O-ring 18 is formed around the recess 16 formed on the side surface 1b of the die 1. Attach the lid 17 with the screw 19 and screw holes 2
When the magnetic paint is applied by screwing the element box 4, the element box 4 is not pushed out by the pressure of the magnetic paint and the magnetic paint does not leak.

When the magnetic coating material is applied on the base film, the die 1 is usually fixed on a support and the magnetic coating material is applied. Therefore, a supporting base suitable for a die in which the element box 4 is arranged in the die 1 as described above will be described. That is, as shown in FIG. 7, the support base 21 is composed of a plate-shaped support portion 21a that supports the die 1 in the width direction and a plate-shaped support portion 21b that supports the die 1 with a height. At this time, since the element box 4 is attached / detached from the hole 14 formed in the side surface 1b of the die 1 as described above, the window 21c for attaching / detaching the element box 4 is attached to the supporting portion 21b facing the side surface 1b of the die 1. And the die 1
21d on the end of the supporting portion 21a that supports the paint in the width direction.
To provide. By disposing the window portion 21c, the element box 4 can be attached / detached while the die 1 is fixed to the support base 21, and the plate element that is the filtering member can be replaced, resulting in high productivity. Furthermore, even if the paint leaks when the element box 4 is attached or detached, the paint receiver 21d
The magnetic paint does not stain the periphery of the device.

As described above, a vertically movable plate-shaped filtering member is arranged in the middle of the slit of the die, and the coating material is extruded through the filtering member to apply the coating on the non-magnetic support. The magnetic paint is extruded with a very high pressure loss, and the pressure distribution in the width direction in the slit of the magnetic paint becomes constant, so that a uniform film thickness distribution and a smooth surface property without streaks can be obtained. You can

Further, since the plate-shaped filter member movable in the vertical direction is used as the filter member, not only a part of the filter member but the entire surface can be used, and the usable period of the filter member is extended. Can and is highly productive. Furthermore, by incorporating the filter member into the unit box that can be detached from the die, without modifying the die,
The installation position, shape, quantity, and specifications of the filtering member can be easily changed only by changing the unit box, and maintenance such as replacement of the filtering member can be easily performed, which is extremely useful.

[0033]

As is apparent from the above description, according to the present invention, a plate-shaped filter member is arranged in the middle of the slit of the die having a paint reservoir, and the magnetic member is provided through this filter member. Since the paint is extruded and applied on the non-magnetic support, the magnetic paint is extruded with a very high pressure loss, and the pressure distribution in the width direction in the slit of the magnetic paint should be constant. It is possible to obtain a uniform film thickness distribution and a smooth surface property without streaks.

Furthermore, since a plate-shaped filter member that can move in the vertical direction is used as the filter member, not only a part of the filter member but the entire surface can be used, and the usable period of the filter member is reduced. It can be extended and has high productivity. Further, in the present invention, it is possible to apply the entire amount of coating material supplied to the die, and it is possible to perform coating without loss,
There is no fear of adversely affecting the coating quality, no advanced flow analysis technology or processing technology is required, the paint pool shape can be made simple, and its practicality is great.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration example of a coating apparatus to which the present invention is applied.

FIG. 2 is a schematic perspective view showing a die partially cut away.

FIG. 3 is a schematic diagram showing a flow of paint when a filter member is arranged.

FIG. 4 is a perspective view showing a configuration example of an element box.

FIG. 5 is a cross-sectional view showing a configuration example of an element box.

FIG. 6 is a perspective view of an essential part showing a detached state of the element box from the die.

FIG. 7 is a perspective view of an essential part showing a configuration example of a support base of a die.

[Explanation of symbols]

 1 ... Die 2 ... Pocket 4 ... Element box 4a ... Plate element 5 ... Slit

Claims (1)

[Claims] 1. An extrusion type which comprises a die having a paint reservoir to which the paint is supplied, and which applies the paint onto a continuously running non-magnetic support while extruding the paint from a slit provided at the tip of the die. In the coating apparatus, the plate-shaped filter member that is movable in the vertical direction is arranged in the middle of the slit of the die, and the coating material is extruded through the filter member and applied onto the non-magnetic support. Coating device.