JP2002254009A - Die head for die coating and die coating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply paint having a strong thixotropy stably and appropriately by restraining variations in thickness of a coating film and coating defects. SOLUTION: A shearing treating means is provided inside a die head 101 that renders a prescribed shearing action to paints. Inside a column-like space 115 formed in a main die body 111, an inner wall face 115a of the space and a rotary axis 116 are arranged with a predetermined gap to form a ring-like circulation space 124. The ring-like circulation space 124 comprises part of a communication channel 114 which communicates a space between a paint supply port 112 and a slit 113a for coating. A rotary axis 116 provides a shearing action against the paint flowing through the ring-like circulation space 124 by rotating at a predetermined revolutionary speed in the arrow A direction, thereby destroying structural viscosity of the paint. This constitution of the paint allows coating in a condition with its viscosity lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die coating die head and a die coating apparatus suitable for use in a step of applying a magnetic paint on a non-magnetic support made of, for example, a plastic film.

[0002]

2. Description of the Related Art Conventionally, a gravure roll coating method, a reverse roll coating method, a die coating method and the like have been used as a method of applying a magnetic layer in a magnetic tape manufacturing process. In the die coating method, there is no rotating part due to its structure, and there is no paint scattering peculiar to the roll coating method, so it can be applied to high speed application,
1000 m / min application is achieved. In addition, since a multilayer film can be simultaneously coated on a wet-on-wet basis and a thin film coating layer according to the required function can be easily produced,
An expensive thin film magnetic layer is used as the outermost layer, and an inexpensive and high-strength lower layer is formed as an underlayer. These are advantages unique to the die coating method, which are difficult to achieve with other conventionally used coating methods.

[0003] However, the die coating method is limited in terms of applicability of the paint, and in the case of a paint having a strong cohesive property or a thixotropic property (hereinafter referred to as a thixotropic property), the roughness of the applied surface after drying is low. In some cases, application to magnetic paint application is difficult due to large size, uneven thickness, or streak-like coating defects.

[0004] These problems can be avoided to some extent by changing the selection or design of the binder or dispersant, which are the compositions of the magnetic paint, in order to improve the coating suitability. However, such restrictions are imposed on the original magnetic tape. It limits the pursuit of required physical properties (eg durability),
It cannot be taken in reality.

Further, recently, as the recording density of a magnetic tape increases, magnetic particles serving as a recording medium tend to be finer. In order to exert the characteristics of tapes using such ultrafine magnetic powders comprehensively, it is required to use a very well-dispersed paint, but such paints often have strong thixotropic properties. Of course, the occurrence of coating defects is further increased.

[0006] In order to solve such a problem, it is necessary to prepare a coating material having coating aptitude which can exert the superiority of die coating without impairing the magnetic and physical characteristics originally required for a magnetic tape, or to prepare a coating material. There has been a need for a die coating method that does not require special application suitability.

[0007] As the latter measure, the structural viscosity of a single line connected between the paint storage tank and the die head is functionally destroyed immediately before entering the die body to improve the applicability of the paint. For example, it is conceivable to install a separate apparatus capable of performing the above operation, for example, a high-pressure homogenizer, a high-speed rotary stirring type disperser, a thin film rotary type disperser, or an ultrasonic wave application type homogenizer.

[0008]

However, in the above-described method, a uniform amount of paint is fed in the coating width direction in the piping system for connecting the single device and the die body, and as a result, the coating is performed. It is necessary to pass through a minimum volume flow path because of designing the paint flow path to suppress the thickness variation, and as a result, a considerable time is required from the end of the shearing process to the actual application. I need it. Specifically, the drying time is 0.2 μm in the dry coating thickness and the coating speed is 25 μm.
When it is 0 m / min, it takes about 1 minute. By this time, the paint recovers its structural viscosity once destroyed,
The effect of improving the viscosity of the paint is weakened, and the occurrence of coating defects cannot be prevented.

Therefore, as shown in FIGS. 11 and 12, for example, a paint supply line 3 and a reflux line 4 are provided between a die head 1 and a paint storage tank 2, while a die body 10 of the die head 1 is provided. Is a supply port 6 and a discharge port 7 connected to the paint supply and reflux lines 3 and 4, respectively, a passage 8 communicating between the supply port 6 and the discharge port 7, and a communication with the passage 8. Forming a slit 9 for coating,
In a die coating apparatus configured with pumps 11 and 12 such that the paint flows through the passage 8 at a sufficiently high flow rate with respect to the amount of the paint applied per unit time from the slit 9, the paint supply port 6 of the die head 1 There is also a configuration example in which a dispersing machine 5 such as the homogenizer is installed in the vicinity to shorten the time (standby time) until the paint is sheared and actually applied (standby time under the above application conditions). Is reduced to a maximum of 30 to 15 seconds).

However, even with the die coating apparatus having the above-described structure, a sufficient effect has not been obtained with respect to a magnetic coating material having strong thixotropy using a metal magnetic powder in recent years, and the waiting time from the shearing treatment to the application is not sufficient. At present, further shortening is desired. However,
Since the shearing effect on the paint is lost due to the volume of the pipe portion from the disperser 5 to the supply port 6 and the volume of the passage 8, the further shortening of the standby time is structurally dependent on the die coating apparatus having the above configuration. It is impossible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a die coating die head and a die capable of stably and appropriately applying a coating material having a strong thixotropy by suppressing the occurrence of coating thickness variations and coating defects. It is an object to provide a coating apparatus.

[0012]

In order to solve the above problems, a die head for die coating according to claim 1 of the present invention comprises a die body, a coating slit formed at one end of the die body, and In a die coating die head formed inside the die body and having a communication passage communicating between a paint supply port to which the paint is supplied and the slit, at least a part of the opposite side wall surfaces of the communication passage is removed. It is characterized in that it is provided with a shearing means for relatively moving each other to apply a shearing action to the paint in the communication passage.

In the present invention, the paint is subjected to a shearing action in the communication passage formed between the paint supply port and the slit, so that the structural viscosity of the paint is destroyed immediately before the paint is discharged from the slit. Thereby, even if the coating material has strong thixotropic properties, it is possible to suppress the occurrence of coating defects such as variations in coating thickness and streak-like defects, and to obtain a stable and proper coating action.

In particular, regarding the structure of the shearing means, the die head for die coating according to claim 2, wherein the communication passage has an inner wall surface of a cylindrical space formed in the width direction of the slit and the cylindrical space. A circular passage formed of an annular gap formed between the rotation shaft and the outer peripheral surface of the rotation shaft having a circular cross section disposed concentrically with the rotation shaft. It is characterized in that it includes a driving means for rotationally driving. As a result, it is possible to suppress an increase in the size of the die head, to simplify the structure, and to design the shearing length of the coating material to be large, so that the coating material can be relatively easily adjusted to a desired viscosity. be able to.

According to another aspect of the present invention, there is provided a die coating apparatus, comprising: a tank for storing paint; a die head for applying paint through a slit having a predetermined width; A die coating apparatus comprising a shearing means for applying a predetermined shearing action to a paint, wherein the shearing means is provided inside a die head.

In the present invention, by providing the shearing means having the above-mentioned structure for applying a shearing action to the paint inside the die head, the waiting time from the shearing treatment of the paint to the application can be greatly reduced compared to the conventional case. Even in the case of a coating material having a thixotropic property, the occurrence of coating defects such as variations in coating thickness and streak-like defects is suppressed, and a stable and proper coating action is obtained.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the present invention is applied to a die coating die head and a die coating apparatus used in a process of applying a magnetic layer on a non-magnetic support in a manufacturing process of a magnetic tape as a tape-shaped magnetic recording medium. An example will be described.

(First Embodiment) FIGS. 1 to 3 show a first embodiment of the present invention. The die coating apparatus 100 in the present embodiment mainly includes a die head 101, a storage tank 102 for magnetic paint, a supply pipe 103 connecting between the die head 101 and the storage tank 102, and a pump 104 for feeding paint. Consists of

The die head 101 has a die body 111 made of a steel material such as die steel.
Has a paint supply port 112 to which the supply pipe 103 is connected.
And a lip portion 113 made of, for example, a cemented carbide, in which a slit 113a for application formed in a predetermined width is formed, and a communication passage 114 communicating between the paint supply port 112 and the slit 113 are provided. I have.

A slit 11 is provided inside the die body 111.
A columnar space 115 is formed over the width direction of 3a,
A rotating shaft 116 facing the inner wall surface 115a of the cylindrical space 115 with a predetermined gap is disposed concentrically with the cylindrical space 115. Inner wall surface 11 of columnar space 115
5a and the outer peripheral surface 116a of the rotating shaft 116 are both mirror-finished, and the distance between the two is 5 μm or more in this embodiment.
0 μm or less. That is, when the thickness is less than 5 μm, the cylindrical space 115 may come into contact with the rotating shaft 116, and when the thickness exceeds 30 μm, a predetermined shearing action on the magnetic paint cannot be obtained as described later. The cylindrical space 115 and the rotating shaft 116 form an annular passage portion 124 formed of an annular gap. The annular passage portion 124 forms a part of the communication passage 114.

The rotating shaft 116 is made of a steel material such as general structural steel, and is preferably subjected to, for example, a ceramic spraying process to impart wear resistance to the outer peripheral surface 116a. Both ends of the rotating shaft 116 are supported in a liquid-tight manner by side plates 128a and 128b attached to both side walls of the die main body 111 via screw members, and one end 116s of the rotating shaft 116 is rotated via a coupling 117. The shaft 115 is connected to a rotation drive unit 118 that rotates the shaft 115 in the direction of arrow A in FIG. 1 (FIG. 2).

The rotation driving unit 118 is configured as a driving unit according to the present invention.
The shaft 12 coupled to the drive shaft of the motor 119 via the pulley 120a, the belt 121a, and the pulley 120b
2a, the pulley 120c and the belt 1 with respect to the shaft 122a.
Shaft 122 connected via 21b and pulley 120d
b, a mechanism for increasing the rotation speed of the motor 119 and transmitting the rotation speed to the rotating shaft 116 is employed.

The columnar space 115, the rotating shaft 116, the rotation driving unit 118 and the like constitute a shearing means according to the present invention.

Referring to FIG. 1, a paint reservoir 125 having a circular cross section for temporarily storing magnetic paint is formed between annular passage portion 124 and paint supply port 112 inside die body 111. . The paint reservoir 125 is formed to have substantially the same width as the width of the annular passage portion 124, and is provided for the purpose of uniformly supplying the magnetic paint to the annular passage portion 124 in the width direction (FIG. 3).

The present embodiment is configured as described above. Next, this operation will be described.

The magnetic paint stored in the storage tank 102 is sequentially supplied at a predetermined pressure to the paint supply port 112 of the die head 101 through the supply pipe 103 under the action of the pump 104. On the other hand, the die body 111
The rotation shaft 116 is rotated at a high speed in the direction of arrow A at a predetermined number of rotations (the number of rotations per unit time, hereinafter the same) by the operation of the rotation drive unit 118.

The magnetic paint supplied to the paint supply port 112 is supplied to the annular passage portion 124 through the paint reservoir 125, and is provided along the rotation direction of the rotating shaft 116.
Flowing inside. After making substantially one round of the annular passage portion 124, the magnetic paint flows into the slit 113a and is applied onto a base film (not shown) running immediately before the lip portion 113.

Here, the magnetic paint flowing through the annular passage portion 124 is subjected to a predetermined shearing action between the stationary wall surface 115a and the wall surface 116a moving with respect to the wall surface 115a. This shearing action is performed over substantially the entire length of the annular passage portion 124, thereby reducing the viscosity of the magnetic paint. The magnitude of the shearing force is determined by the gap and length of the annular passage portion 124, the rotation speed of the rotating shaft 116, and the like.

At this time, the rotary shaft 116 forms a shear flow in the annular passage portion 124 to prevent the magnetic paint from flowing directly from the paint reservoir 125 into the slit 113a.
Is required. In order to stably generate this shear flow, a sufficient paint supply pressure is required to fill the annular passage portion 124 and the passage from its outlet to the slit 113a with magnetic paint. For example, in the embodiment described later, when the rotation speed is 13500 RPM,
The inlet pressure was 0.17 MPa (gauge pressure).

As described above, according to the present embodiment, the magnetic paint is applied after the shearing action is performed on the magnetic paint inside the die head 101. Therefore, the waiting time from the shearing treatment of the magnetic paint to the application is performed. Can be significantly reduced (less than 0.1 second) than before, and even with a magnetic coating material having strong thixotropic properties, the occurrence of coating defects such as variations in coating thickness and streak-like defects is suppressed, and appropriate and stable The application effect of the magnetic paint can be realized.

Further, according to the present embodiment, since the shearing action on the magnetic paint is performed in the annular passage portion 124, the shearing action on the magnetic paint is performed while suppressing the die body 111 from being enlarged. In addition, a sufficient flow path length can be secured, and the magnetic paint can be stably discharged without pulsation. In addition, by adjusting the rotation speed of the rotation shaft 116, the viscosity of the magnetic paint can be arbitrarily adjusted.

(Second Embodiment) FIGS. 4 and 5 show a second embodiment of the present invention.

The die coating apparatus 20 of the present embodiment
0 is mainly a die head 201, a magnetic paint storage tank 202, and supply pipes 203a, 203b connecting between the die head 201 and the storage tank 202.
And a pump 204 for feeding the paint.

The die head 201 of this embodiment has the same configuration as the die head 101 of the above-described first embodiment, and includes a die body 211 having a columnar space 215 formed therein, and a die space 211 having a cylindrical space 215 therein. A rotating shaft 216 arranged concentrically with the cylindrical space 215 at a predetermined gap from the wall surface 215a, and a slit 213 formed at a predetermined width;
and a communication passage 214 communicating between the paint reservoir 225 of the die body 211 and the slit 213a. The annular passage portion 224 formed at a portion forms a part of the communication passage 214.

Although not shown, the rotary shaft 216 is connected to a drive unit having the same configuration as the rotary drive unit 118 described in the first embodiment, and the rotary shaft 216 can rotate in the direction of arrow A in FIG. Is configured.

Die head 201 in the present embodiment
As shown in FIG. 5, a porous tube member 226, such as a sintered metal pipe, having substantially the same length as the formation width of the slit 213a (application width of the coating material) is accommodated in the coating material reservoir 225. , Both ends 226a, 226b of this pipe member 226
Are connected to supply pipes 203a and 203b, respectively, to form paint supply ports. Both ends 226a, 226 of tube member 226
b are side plates 228a, 228 attached to both sides of the die body 211 via seal rings 227a, 227b.
8b are fixed to the mounting holes 229a and 229b.

In the present embodiment configured as described above, by supplying the magnetic paint from both ends 226a and 226b of the pipe member 226, the pressure loss when the magnetic paint passes through the cross section of the pipe member 226 is reduced. Is sufficiently larger than the pressure loss when flows through the inside of the pipe member 226 in the longitudinal direction (application width direction), so that the magnetic paint can be uniformly supplied to the annular passage portion 224 in the width direction. As a result, it has been confirmed that the variation in the coating thickness in the width direction can be reduced, and the experiment by the present inventors can suppress the variation to within ± 5%.

Further, instead of supplying the magnetic paint from both ends of the pipe member 226, an amount of 3 to 10 times the amount required for application is supplied from one end of the pipe member 226, and excess magnetic paint is supplied from the other end. It has been confirmed that the same thickness accuracy can be obtained also by the configuration of collecting and returning to the storage tank 202 again.

At the time of die coating, the die head 201 is arranged such that a part of the annular passage 224 forms the uppermost paint flow passage inside the die body 211 as shown in FIG. Air bubbles (air) remaining inside the die body 211 can be effectively discharged to the outside together with the magnetic paint, and it is possible to prevent the occurrence of coating defects due to insufficient air removal inside the die body 211. Become. In the illustrated example, the slit 213a
Are opened vertically downward, which contributes to reduction in variation in the thickness of the magnetic paint applied on the base film B running in the horizontal direction.

(Third Embodiment) FIGS. 6 and 7 show a third embodiment of the present invention. In the drawings, parts corresponding to those in the above-described second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Die head 301 in the present embodiment
Is provided with a die main body 311 having a configuration basically similar to those of the above-described first and second embodiments, and a rotating shaft 316 arranged in a cylindrical space 215 in the die main body 311. The present embodiment differs from the above embodiments in that cooling means is provided for the die body 311 and the rotating shaft 316 so as to suppress a rise in the temperature of the magnetic paint due to the shearing process and to obtain a stable shearing effect.

That is, in the die body 311, a plurality of water pipes 305 are inserted in the coating width direction as shown in FIG. 6, and cooling water is circulated between the water pipes 305 to form the die body 311. 311 is intended to be cooled. In addition, as shown in FIG. 7, the rotary shaft 316 supplies cooling water to the jacket 307 in the rotary shaft 316 through the water pipe 306 inserted into one end 316t of the rotary shaft 316. By discharging the water, the rotation shaft 316 is cooled.

As described above, the variation in the shearing effect due to the temperature change of the magnetic paint is suppressed, and the magnetic paint adjusted to have a constant viscosity is continuously discharged, so that the desired magnetic properties without the variation in the coating thickness and the coating defect can be obtained. The layer is formed stably.

(Fourth Embodiment) FIG. 8 shows a fourth embodiment of the present invention.
Is shown. The die head 401 of the present embodiment has a multi-layered tape-shaped magnetic recording in which a non-magnetic layer 42 is formed on a main surface of a non-magnetic support 41 as shown in FIG. 9 and a magnetic layer 43 is formed thereon. It is used in a die coating device for producing the medium 40.

Here, the nonmagnetic support 41 is made of, for example, a polyester resin such as polyethylene terephthalate or the like, and forms a base film of the magnetic recording medium 40. In addition, the nonmagnetic layer 42 is formed by dispersing in an organic solvent a nonmagnetic powder such as titanium oxide or hematite (α-Fe ₂ O ₃ ) and a binder as a main component together with a dispersant, a lubricant, or the like, and adjusting the nonmagnetic powder. It is made of a magnetic paint and is applied on the non-magnetic support 41. The magnetic layer 43 is made of, for example, a magnetic paint prepared by dispersing a metal powder containing iron as a main component as a magnetic powder in an organic solvent together with a binder, a dispersant, and a lubricant, and adjusting the magnetic powder. Applied.

The die head 401 includes a die body 411A for applying a non-magnetic paint and a die body 411B for applying a magnetic paint. The die body 411A has a paint supply unit 425A to which a non-magnetic paint is supplied, a slit 413A for application, and a communication passage 414A connecting these. The die main body 411B has a paint supply unit (paint reservoir) 425B to which the magnetic paint is supplied, a slit 413B for application, and a communication passage 414B that connects these, and an annular part that forms a part of the communication passage 414B. Passage 4
24 is a columnar space 415 as in the above embodiments.
And the rotating shaft 416 is formed by an annular gap.

The slits 413A and 413B are arranged adjacent to each other, and a non-magnetic coating material and a magnetic coating material are sequentially applied to the non-magnetic support 41 running immediately before the slits 413A and 413B, so that the magnetic material shown in FIG. The recording medium 40 is manufactured.

At this time, the magnetic paint is subjected to a predetermined shearing action in the annular passage portion 424 of the die body 411B, and is applied in a state where its structural viscosity is destroyed. It is possible to stably form the magnetic layer 43 as thin as 0.3 μm.

[0049]

Embodiments (Embodiments 1 to 5) One embodiment of the present invention will be described below. In this example, the viscosity of the paint discharged from the slit 113a was measured using the die head 101 (see FIGS. 1 to 3) having the configuration of the first embodiment described above.

The conditions for implementation are as follows: the diameter of the cylindrical space 115 in the die body 111 is 40 mm, the diameter of the rotary shaft 116 is 39.98 mm, the size of the gap forming the annular passage 124 is 10 μm, and the opening of the slit 113 a is The gap is 0.1 mm, the slit width is 125 mm, the distance between the exit of the annular passage 124 and the opening of the slit 113a is 45 mm, and the number of rotations of the rotating shaft 116 is 2700-13.
It was varied in the range of 500 RPM. Table 1 shows the change in the viscosity of the coating material subjected to the shearing treatment under these rotation speed conditions, as compared with the case where the coating material was not subjected to the shearing treatment.

[0051]

[Table 1]

The magnetic paint used as the sample was composed of fine metal powder, and usually used a paint having strong thixotropy. The composition of the paint is shown below. <Coating composition for magnetic layer of magnetic recording medium B> Metal magnetic powder: 100 parts by weight (σs = 150 Am ² / k)
g, Hc = 130 kA / m, specific surface area 5 by BET method
5 m ² / g) PVC copolymer: 15 parts by weight (trade name M, manufactured by Zeon Corporation)
R-110) Polyester polyurethane resin: 5 parts by weight (isophthalic acid / terephthalic acid / butanediol-MDI-based polyurethane molecular weight 25,000, polar group: SO ₃ Na = 0.2)
α-Al ₂ O ₃ : 10 parts by weight (trade name: H, manufactured by Sumitomo Chemical Co., Ltd.)
IT-50) Carbon black: 1 part by weight (manufactured by Cabot Corporation, trade name: BP-L) Polyisocyanate: 4 parts by weight (manufactured by Nippon Polyurethane Co., trade name: Coronate L) Myristic acid: 1 part by weight Butyl stearate: 1 part by weight Parts Methyl ethyl ketone: 80 parts by weight Methyl isobutyl ketone: 80 parts by weight Toluene: 80 parts by weight

The above magnetic layer coating composition was kneaded with a continuous kneader and then dispersed using a sand mill. Thereafter, 4 parts by weight of polyisocyanate and 1 part by weight of myristic acid were added, and the mixture was filtered through a filter having an average diameter of 1 μm to obtain a coating material for a magnetic layer.

As is evident from Table 1, when a shear force is applied to the paint, the structural viscosity is destroyed, and the viscosity drops sharply.
It can be seen that increasing the shear rate further reduces the viscosity of the coating. According to the present embodiment, once the shearing treatment is applied, the coating material reaches the application portion only by passing through the slit gap, but the required time is 0.072 seconds when the dry coating thickness is 0.2 μm, That is, the time is 0.1 second or less.

According to this example, compared with the case where no shearing treatment was applied to the paint, the flow of the paint during the coating operation was smooth, so that the coating was easy to apply and there were few or no macro defects such as streaks. Further, according to the present embodiment, a thin coating film which could not be adjusted due to the occurrence of coating defects could be appropriately and stably obtained. Table 2 shows the results.

[0056]

[Table 2]

The number of streak-like defects shown in Table 2 is the number of occurrences per 100 mm of coating width.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.

For example, in each of the above embodiments, the shear processing means according to the present invention is configured as described above. Alternatively, for example, the reciprocating motion of the piston may be used, or the cross-sectional shape of the rotating shaft may be circular. It is also possible to apply a shearing action to the paint by adopting a shape other than the above. In this case, it is desirable to take a means capable of absorbing the pulsation of the discharged paint.

Further, in each of the above embodiments, an example in which the present invention is applied to a die coating die head and a die coating apparatus for applying a magnetic paint has been described. However, the present invention is not limited to this. The present invention is applicable to the application of other paints, especially paints having strong thixotropy.

[0061]

As described above, according to the present invention, the following effects can be obtained.

That is, according to the die head for die coating according to the first aspect of the present invention, it is possible to destroy the structural viscosity of the paint immediately before discharging the paint from the slit, and the paint has a strong thixotropic property. In addition, it is possible to suppress the occurrence of coating defects such as variations in coating thickness and streak-like defects, and to obtain a stable and proper coating action.

According to the second aspect of the present invention, it is possible to secure a sufficient flow path length for performing a shearing action on the paint while suppressing an increase in the size of the die body, and to stabilize the flow without pulsation. To discharge the paint. Also,
The paint can be arbitrarily adjusted to a desired viscosity by adjusting the rotation speed of the rotating shaft.

According to the third aspect of the present invention, the variation in the effect of the shearing treatment due to the change in the temperature of the coating material is suppressed, and the coating material adjusted to a constant viscosity by the shearing processing means is continuously discharged, so that the coating thickness varies. And a desired coating layer without coating defects can be formed stably.

According to the fourth aspect of the present invention, the paint can be uniformly supplied to the annular passage portion in the width direction, and the variation in the coating thickness in the width direction can be reduced.

According to the invention of claim 5, for example, the present invention can be applied to a die head for manufacturing a magnetic recording medium having a multilayer structure,
It is possible to stably form a high-quality thin-film magnetic layer with high film thickness accuracy.

According to the sixth aspect of the present invention, air bubbles (air) remaining inside the die body can be effectively discharged to the outside together with the paint, and a coating defect occurs due to insufficient air release inside the die body. Can be prevented beforehand.

Further, according to the die coating apparatus of the present invention, since the shearing means for applying a shearing action to the paint is provided inside the die head, the coating is started from the shearing of the paint. The waiting time before the application can be greatly reduced compared to the conventional method, and even if the paint has strong thixotropy, it is possible to suppress the occurrence of variations in the coating thickness and the occurrence of streak-like defects, etc., and obtain an appropriate and stable coating action. Can be.

According to the eighth aspect of the present invention, it is possible to secure a sufficient flow path length for performing a shearing action on the coating material while suppressing the enlargement of the die body, and to stabilize the flow without pulsation. To discharge the paint.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a die coating apparatus and a die head according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line [2]-[2] in FIG.

FIG. 3 is a sectional view taken along the line [3]-[3] in FIG.

FIG. 4 is a side sectional view showing a configuration of a die head according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line [5]-[5] in FIG.

FIG. 6 is a side sectional view showing a configuration of a die head according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a rotating shaft according to a third embodiment of the present invention.

FIG. 8 is a side sectional view showing a configuration of a die head according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing a configuration of a magnetic recording medium manufactured by a die head according to a fourth embodiment of the present invention.

FIG. 10 is a side sectional view for explaining a preferable application posture at the time of die coating of the die head according to the embodiment of the present invention.

FIG. 11 is a fragmentary sectional view showing an example of a conventional die coating apparatus.

FIG. 12 is a side sectional view showing a configuration of a die head in the die coating apparatus shown in FIG.

[Explanation of symbols]

100, 200: die coating apparatus, 101, 20
1, 301, 401: die head, 102, 202: storage tank, 103, 203: supply pipe, 111, 21
1, 311, 411: die body, 112: paint supply port,
113a, 213a, 413A, 413B ... slit,
114, 214, 414 ... communication passage, 115, 215
415: cylindrical space, 116, 216, 316, 416
... Rotary shaft, 18 ... Rotation drive unit (drive means), 124, 2
24, 424: annular passage portion, 125, 225, 425B
... paint pool, 226 ... porous tube member, 305, 306 ...
Water pipe (cooling means).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 AC02 AC72 AE23 CA24 CA48 DA04 DB36 DB48 DC28 EA10 EA19 EB01 EB11 EB31 EB52 EB56 EB57 4F041 AA12 AB01 BA12 CA02 5D112 AA01 AA30 CC01 CC08

Claims (8)

[Claims] 1. A die body, an application slit formed at one end of the die body, and a communication between a paint supply port formed inside the die body and supplied with paint, and the slit. A die coating die head provided with a communication passage, comprising: a shearing means for moving at least a part of opposed side walls of the communication passage relative to each other to apply a shearing action to the paint in the communication passage. A die head for die coating, characterized in that: 2. An inner wall surface of a cylindrical space formed over the width direction of the slit, and an outer peripheral surface of a rotary shaft having a circular cross section disposed concentrically with the inside of the cylindrical space. The die according to claim 1, further comprising: an annular passage portion formed of an annular gap formed between the die and the shear processing unit, wherein the shearing unit includes a driving unit that rotationally drives the rotation shaft. Die head for coating. 3. The die head for die coating according to claim 2, wherein cooling means for cooling the die body and the rotating shaft is provided. 4. A paint reservoir for temporarily storing paint is formed between the shearing means and the paint supply port, and one or both ends of the paint reservoir are the paint supply port inside the paint reservoir. The die head for die coating according to claim 1, wherein a porous tube member is arranged. 5. The die coating die head according to claim 1, wherein a die for applying a paint different from the paint is provided adjacent to the die body. 6. The die head for die coating according to claim 2, wherein at the time of die coating, a part of the annular passage forms an uppermost paint flow path inside the die body. 7. A paint storage tank, a die head for applying the paint through a slit formed in a predetermined width,
A die coating apparatus comprising a shearing means for applying a predetermined shearing action to the paint, wherein the shearing means is provided inside the die head. 8. A cross-section in which the shearing means is arranged inside the die head in a columnar space formed over the width direction of the slit, and opposed to an inner wall surface of the columnar space with a predetermined gap therebetween. The die coating apparatus according to claim 7, further comprising: a rotation shaft for driving the rotation shaft;