JPH08150361A - Coating applicator - Google Patents

Abstract

PURPOSE: To provide a coating applicator capable of surely removing deposits, such as dust, which are not removable by air blowing and wet process, etc., with a simple structure. CONSTITUTION: A tacky adhesive revolving roll 11 which removes the deposits F sticking to a flexible substrate (base film) 7 is arranged upstream of a die 1 of a coating applicator of an extrusion system which applies a magnetic coating material under extrusion from a slit 4 onto the flexible substrate (base film) 7 traveling continuously along a front blade 8 surface and smoothing blade 9 surface at the front end of the die.

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 used for manufacturing magnetic recording media and the like.

[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. Has become.

However, in these roll coating methods, fluctuations in output due to coating thickness unevenness due to defective transfer of coating material from the roll to the base film, drop-out due to coating material scattering, and excessive supply of coating material are returned to the mixing process. There are problems such as deterioration of paint quality, and these problems tend to become more prominent especially as high-speed coating is performed.

In recent years, as a new coating method capable of solving these problems, an extrusion (die) method has been attracting attention, and it has already been partially put into practical use in the manufacturing process of a coating type magnetic recording medium.

As shown in FIG. 11, the extrusion method uses a die 101 which has a narrow slit at a tip portion with a predetermined width and has a doctor edge in the vicinity of the tip portion. The coating material continuously extruded toward the substrate is applied to the support 107 with a uniform thickness by the doctor-edged surface, which has been used in the fields of photographic film, photographic paper, etc. Is.

[0006]

By the way, in the extrusion type coating apparatus, the deposit F such as dust adheres to the surface of the moving support due to various factors.

That is, in the coating step, the support 107 wound in a roll shape is unwound, the magnetic paint is applied to the support 107 to a uniform thickness, and the major axis of the magnetic powder in the paint is adjusted. There is winding in which the dried magnetic recording medium is wound after being dried (dryer) in which the magnetic layer is fixed on the support by evaporating the organic solvent in the magnetic coating in a uniform orientation. In addition to the guide roller 105 that guides the support body to each of the above-mentioned steps, and also to the human body, dust and the like adhere due to various factors in the above-mentioned steps. Moreover, since the above process is usually performed at high speed, it is not easy to remove dust and the like.

When such an adhering substance F such as dust adheres to the surface of the moving support 107 and is caught on the die 101 as shown in FIG. 11, the front blade 108 is moved.
On the side, even if it is a streak with a thick coating thickness, it rises in a convex shape,
On the other hand, on the side of the smoothing blade 109, a phenomenon occurs in which the coating thickness is reduced to a concave shape. Then, when these are wound up, they appear as black and white streaks, respectively. When the winding is performed in the state where the streaks are generated, the streaks are stacked, so that the magnetic recording medium is deformed in shape and the characteristics such as yield are deteriorated.

Therefore, a method of removing the adhering matter such as the dust is problematic, and in order to eliminate the streak phenomenon, for example, a method of blowing high-speed air to remove the dust or the like, or As disclosed in Japanese Patent Laid-Open No. 59-150571, there is a method in which a solvent or a solution containing a primer is applied before the magnetic paint is applied to wipe and wash the applied surface by a wet method. .

However, in any method such as the above-mentioned air blowing or wet method, since dust and the like are generated in the coating step due to various factors, the dust and the like cannot be removed sufficiently, In the wet method,
It had the following problems.

First, in the above-mentioned wet method, the characteristics of the magnetic tape cannot be obtained because re-aggregation is caused by the solvent as the characteristics of the coating material, and the magnetic coating material that can be handled by this method is limited.

Further, since a solvent which is more than the solvent contained in the magnetic paint is used, there is a limitation in applying the magnetic paint at high speed due to the processing capability of the drying (dryer) and the solvent recovery device. Even if it is dried before applying the magnetic paint in order to solve this, the result is the same, and if it is attempted to solve this, a new equipment investment is made and the cost is increased.

Therefore, an object of the present invention is to provide a coating apparatus capable of surely removing adhered matters such as dust which cannot be removed by air blowing or a wet method with a simple structure.

[0014]

In order to achieve the above-mentioned object, the inventors of the present invention have studied in detail the factors for the generation of deposits such as dust in the coating process and the mechanism of the generation of streaks in the coating film. It was found that removing adherents with an adhesive rotating roll coated with an adhesive is effective for removing adherents such as dust that cannot be removed by air blowing or a wet method, and the present invention has been completed. It was

In the coating apparatus according to the present invention, the extruding coating is applied while extruding the magnetic coating material from the slit on the flexible support which continuously runs along the front blade surface and the smoothing blade surface at the tip of the die. The rouge type applicator is characterized in that an adhesive rotation roll for removing deposits adhering to the flexible support is arranged upstream of the die.

Further, a plurality of the adhesive rotation rolls are arranged on a rotating member that rotates in an arc shape, and each of the adhesive rotation rolls is rotated and comes into contact with the flexible support alternately. Further, the adhesive rotation rolls are arranged on a plurality of elevating members which are alternately moved up and down, and these adhesive rotation rolls are moved up and down with respect to the flexible support and are alternately contacted.

[0017]

In the coating step, the support wound in a roll shape is sent out at high speed and guided by the guide roller, and then the coating material is coated with the magnetic coating material. In such a process, as a streak caused by a deposit on the coating film, as shown in FIG. 9, a traveling system such as a guide roller arranged in the coating process from the initial mixing of dust or the like, and a die There are various factors such as the tip portion (lip portion) sensitively trapping the adhering matter, and it has not been sufficiently removed by the conventional wet method or the like.

According to the coating apparatus of the present invention, the adherent rotating roll removes the adhering substances such as dust adhering to the flexible support as described above. Therefore, the adhering substances that have not been removed by the conventional wet method are removed, and it is possible to reliably prevent the generation of streaks during winding.

Further, unwinding is usually performed at high speed. For this reason, a plurality of the adhesive rotation rolls are arranged on a rotating member that rotates in an arc shape, and the adhesive rotation rolls are arranged on a plurality of elevating members that alternately move up and down. The deposit can be removed without stopping the apparatus.

[0020]

EXAMPLES A coating apparatus to which the present invention is applied will be specifically described below.

Example 1 In this example, as shown in FIGS. 1 and 2, in a so-called extrusion die coating system, the base film 7 as the flexible support is attached upstream of the die 1. It is characterized in that the adhesive rotation roll 11 for removing the deposit F is arranged.

The coating apparatus of this embodiment is used for coating the magnetic coating material in the manufacturing process of the coating type magnetic recording medium, and the magnetic coating material 3 is placed in the pocket (coating material reservoir) 2 of the die (extruder) 1. It is supplied, is supplied to the slit 4, is extruded, and is applied onto the base film 7 which is run through the guide roller 5 and the like.

As shown in FIG. 6, the die 1 is made of a metal block having a substantially rectangular parallelepiped shape having a predetermined width, and the tip portion thereof is shaved obliquely to form a so-called wedge shape, and its tip end is formed. A front blade 8 and a smoothing blade 9 made of cemented carbide or the like are integrally provided on the portion 1a.

The die 1 has a tip surface 1
A slit 4 is formed so as to face a, depending on the coating width. The slit 4 is a gap through which the paint is extruded, and is usually a very narrow gap of about 0.01 to 2 mm. It

On the back side of the slit 4, a pocket 2 communicating with the slit 4 is formed as a cylindrical space having a length substantially equal to the width of the slit 4. At both ends of the pocket 2, paint supply ports 6 and 10 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 the magnetic paint 3 is formed. Are supplied to the pocket 2. Therefore, the pocket 2 becomes a space for receiving the paint pressure-fed from the paint supply device and has a function of an accumulator. In addition, reference numeral 16 in the figure
A paint supply device for the magnetic paint 3.

In the coating apparatus having such a structure, the magnetic coating material 3 supplied from the precision coating material supplying apparatus to the pocket 2 of the die 1 has its coating pressure uniformized by its accumulator effect and is uniformly extruded into the slit 4. Be done. The base film 7 includes a front blade 8 and a smoothing blade 9 provided at the exit end of the slit 4.
The magnetic paint 3 extruded from the slit 4 is continuously run in a state of being held along with the smoothing blade 9 to form a coating film having a uniform coating thickness and a smooth surface.

In particular, an adhesive rotation roll 11 is arranged upstream of the die 1 at a position where it contacts the base film 7. This adhesive rotation roll 11 is a rotation roll type in which an adhesive 17 is applied to the outer periphery,
The diameter is 80 mm × 700 mm (Length). In addition, FIG. 1 shows the adhesive rotation roll 11 arranged at one position upstream of the die 1, and FIG. 2 shows the adhesive rotation roll 1 at two positions via the guide roller 5.
1 is arranged.

As the adhesive rotation roll 11, for example, the configuration shown in FIGS. 3 and 4 can be considered. First,
3 is a rotary roll type in which an adhesive 17 is applied on the outer circumference, and is equipped with rotary shafts 12, 12 in the front and rear and is rotatably supported by a headstock 13. The adhesive rotation roll 11 shown in FIG. 3 rotates with the movement of the base film 7 and is not provided with a drive means.

On the other hand, the one shown in FIG.
2 and 12, which are rotatably supported by headstocks 13 and 13, and a motor 14 which is a driving means on the rotary shaft 12.
Is provided. According to such an adhesive roll 11 provided with a driving means, tension acts and it is possible to sufficiently cope with high-speed coating.

Next, the position where the adhesive rotation roll 11 is disposed is upstream of the die 1, and in this embodiment, the adhesive rotation roll 11 is fixed from the die 1 through some of the guide rollers 5. It is placed at a distance.

That is, in practice, the position where the adhesive rotation roll 11 is arranged is extremely important in order to effectively remove the adhering matter F such as dust generated by various factors. In this respect, in consideration of the fact that the deposit F is also generated from the guide roller 5, it is theoretically preferable to dispose it in the vicinity of the upstream side of the die 1.

However, since the base film 7 is adhered by the adhesive rotation roll 11 and tension is applied and static electricity is generated, these points are taken into consideration. In this embodiment, the die 11 is used. It is located at a certain distance from. In an actual experiment, it was effective to dispose the adhesive rotation roll 11 as shown in FIG. 5 for removing dust and the like. As shown in FIGS. 2 and 5, the guide roller 5
It is preferable to dispose through the guide roller 5 also from the viewpoint of removing dust and the like generated from the guide roller 5.

Next, the magnetic coating material was actually applied by varying the number of the adhesive rotation rolls, and the effect of the present invention was confirmed. The composition of the die used in the experiment, the coating conditions, the paint, etc. are as follows.

<Structure of Die> Die: Extrusion die with a total width of 700 mm and coating width of 610 mm Pocket: Cylindrical hole with a diameter of 40 mm penetrates in the width direction of the die Slit: Gap of 0.25 mm Front blade: Thickness of 5 mm Cemented Carbide Smoothing Blade: Cemented Carbide with a Wall Thickness of 5 mm The coating conditions and the composition of the coating used are as follows.

<Coating Conditions> Base film: width / length 620 mm × 1000 mm: polyethylene terephthalate film having a thickness of 14.5 μm Coating speed: 350 m / min Coating thickness: 3.0 μm <Paint> Solid content: 39.0 weight % Clay: 2800 cps (B type viscometer) <Paint supply device> High precision gear pump Discharge rate: 70 cc / rev Drive / control: Line speed control using an inverter motor Filter: Set of 7 cylindrical filters with absolute filtration accuracy of 5 μm When actually applying the magnetic coating material 3 to the base film 7 using the coating device having the above-described configuration, the adhesive rotation roll 11 is arranged on the coating surface side upstream of the die 1 via the guide roll 10. To do.

Experimental Results As shown in FIG. 9, the inventors of the present invention have investigated the cause of streaks on the adhered material and the coating film, such as the guide roller 5 arranged in the coating process from the initial mixing of dust or the like. It was clarified that the running system and the tip part (lip part) of the die are sensitive to trapping the adhering substances, and the following experiments were conducted.

Then, the generation of thin and thick streaks of coating thickness caused by foreign matter such as dust caught on the front blade 8 and the smoothing blade 9 was investigated. The specific results are shown in Table 1. Table 1 summarizes the results of the experiment in the case of not using the adhesive rotary roll and in the case of using the adhesive rotary roll and increasing the number of the adhesive rotary rolls.
The following shows the average.

[0038]

[Table 1]

As is clear from Table 1, the more the number of the adhesive rotation rolls 11 increases, the more reliably the occurrence of streaks can be prevented. That is, when the adhesive rotation roll 11 is not used, the occurrence rate (number of streaks /
The number of coating rolls) was 3.5, but 2.2 when one adhesive rotation roll 11 according to the above-mentioned example was arranged,
When two are arranged, the value is 1.5, and when four are arranged, it is 0.6, which shows a gradually lower value.

Therefore, according to this embodiment, the generation of streaks is surely suppressed, and as the number of the adhesive rotation rolls 11 is increased, the streak generation rate is lowered, and even when winding is performed. Example 2 which is to be wound up neatly In the coating apparatus of this example, as shown in FIG. 7, a plurality of adhesive rotation rolls 21 are arranged on a rotating member 22 that rotates in an arc shape. , 21 are rotated with respect to the flexible support 7 and are alternately contacted with each other.

The rotary member 22 is configured so as to be rotatable in an arc shape around the shaft 23 in the arrow direction in the drawing between the guide rollers 5 and 5 upstream of the die 1, and the end portion of the rotary member 22. Two of the above adhesive rotation rolls 2 on the side
1, 21 are arranged respectively.

In this embodiment, two adhesive rotation rolls 21 are arranged, but it is also possible to arrange two or more by changing the shape of the rotation member 22 according to the implementation. In addition, other than that, the configuration of the adhesive 27 and the like is the same as in the case of the first embodiment.

Therefore, when the coating step is actually performed using the embodiment having the above-described structure, first, one adhesive rotation roll 21a is placed in a state of being adhered to the base film 7. Then, after removing the adhering matter F for a certain time or length, the rotating member 22 is rotated about its axis,
The other adhesive rotation roll 21b is placed in a state of being bonded to the base film 7. And such an adhesive rotation roll 21a
In the standby state, the adhesive rotation roll 21a having the adhered matter F attached thereto is replaced.

By removing the adhering substance F while sequentially exchanging in this way, the adhering substance F can be removed without stopping the coating device for cleaning the adhesive rotation roll 21. Therefore, unwinding at high speed
It is particularly significant for modern coating equipment that requires high speed coating.

Then, similarly to the first embodiment, the occurrence rate of streaks was examined. As a condition in this case, the adhesive rotating rolls 21 and 21 having the above-described configuration were arranged at one location upstream of the die 1, and the occurrence rate of streaks (number of streaks /
The coating roll) showed a low value of 1.2. Therefore, it can be seen that a stable coating state is obtained. Since the above-mentioned experimental results are obtained at one place, even better results can be expected when the above-mentioned examples are arranged at two or more places.

Embodiment 3 In the coating apparatus of this embodiment, as shown in FIG. 8, the adhesive rotation rolls 31 are arranged on a plurality of elevating members 32 which are alternately moved up and down, and the adhesive rotation rolls 31, 31 are respectively arranged. Are alternately contacted with the flexible support 7.

The elevating member 32 is arranged between the guide rollers 5 and 5 upstream of the die 1 between the cylinder 33,
It is configured such that it can be moved up and down in the direction of the arrow in the drawing by the reference numeral 33, and 2 is provided on the end side of the lifting member 32 constituted by these.
Each of the above-mentioned adhesive rotation rolls 31 is arranged.

Also in this embodiment, as in the case of the above-described first and second embodiments, the adhesive rotation roll 31 may be composed of two or more. In addition, the adhesive 37
The configurations such as are similar to those in the above-described first and second embodiments.

Therefore, when the coating step is actually performed using the embodiment having the above-described structure, first, one adhesive rotation roll 31a is placed in a state of being bonded to the base film 7. Then, after removing the deposit F for a certain period of time or length, each of the cylinders 33 is moved up and down, and the other adhesive rotation roll 31b is placed in a state of being bonded to the base film 7. Then, in the standby state of the adhesive rotation roll 31a, the adhesion rotation roll 3 to which the attached matter F is attached
Replace 1a.

By removing the adhering material F while sequentially replacing the adhering material in this manner, the adhering material F can be removed without stopping the coating device 1 for cleaning the adhesive rotation roll 11.
It is particularly meaningful for the recent coating apparatus which requires high speed unwinding and high speed coating.

Although the occurrence rate of streaks was not examined in this embodiment, substantially the same result as in the second embodiment can be expected.

By the way, the present inventors consider that it is indispensable to remove the deposit F because there are various factors such as adhesion of dust and the like to the base film 7, and the following analysis and examination are also included. went.

That is, with respect to the adhered substance F adhered to the adhesive rotation roll 11, an example in which the container film traveled 500 m was analyzed. FIG. 10 shows the result. In the figure, the term "contamin" means foreign matter such as dust.
on).

As a result of the above analysis, the human factor is 25.8.
%, Cellulose was 19.4%, and polyethylene terephthalate (PET) was 35.5%.

In this embodiment, the case where the present invention is applied to the method of manufacturing a magnetic recording medium has been described, but it goes without saying that the present invention can also be applied to a method of manufacturing photographic film, photographic paper and the like.

[0056]

EFFECT OF THE INVENTION The coating apparatus according to the present invention is an extruding device for applying magnetic coating material through a slit onto a flexible support which continuously runs along the front blade surface and the smoothing blade surface of the die tip. In the rouge type die coating method, since the adhesive rotation roll for removing the adhered matter adhering to the flexible support is arranged upstream of the die, dust adhered to the flexible support by the adhesive rotation roll. And the like are removed. Therefore, the deposits that were not removed by the conventional wet method are removed,
It is possible to reliably prevent the generation of streaks during winding and obtain a good coating state.

Since no solvent is used as in the prior art, the magnetic properties are not deteriorated by re-aggregation and the magnetic tape properties are not affected.

Further, when a plurality of the above-mentioned adhesive rotation rolls are arranged on a rotating member which makes contact with the flexible support while rotating, or when arranged respectively on a plurality of elevating members which alternately move up and down, the adhesive rotation rolls are rotated. The deposit can be removed without stopping the coating device for cleaning the roll. Therefore, the load is not added to the processing capacity of the dryer (dryer) and the solvent recovery device unlike the conventional device, and moreover, it is possible to effectively cope with the recent application device that requires high-speed unwinding and high-speed application. it can.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a schematic configuration of a coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically showing a schematic configuration in the case where a plurality of adhesive rotation rolls are arranged in the coating apparatus according to the above embodiment.

FIG. 3 is a cross-sectional view showing the structure of the adhesive rotation roll used in the first embodiment.

FIG. 4 is a cross-sectional view showing the configuration of another adhesive rotation roll used in the first embodiment.

FIG. 5 is a diagram showing a schematic configuration in the case where the arrangement positions of a plurality of adhesive rotation rolls are changed in the first embodiment.

FIG. 6 is a schematic perspective view showing the die according to the first embodiment with a part thereof cut away.

FIG. 7 is a diagram schematically showing a schematic configuration of a coating apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram schematically showing a schematic configuration of a coating apparatus of a third embodiment to which the present invention is applied.

FIG. 9 is a diagram showing the results of analysis and examination of adhering substances such as dust using each of the present examples.

FIG. 10 is a diagram schematically showing an adhering matter such as dust and a generation mechanism in which streaks are generated by the adhering matter.

FIG. 11 is a perspective view showing a state in which streaks are generated on a base film due to an attached matter.

[Explanation of symbols]

1 Die 4 Slit 5 Guide Roller 7 Base Film (Support) 8a Front Blade Surface 9a Smoothing Blade Surface 11, 21, 21a, 21b, 31, 31a, 31b
Adhesive rotating roll 17, 27, 37 Adhesive 22 Rotating member 32 Lifting member 33 Cylinder F Adhesion

Claims (3)

[Claims] 1. An extrusion-type coating apparatus for coating a flexible support which runs continuously along the front blade surface and the smoothing blade surface at the tip of a die while extruding a magnetic coating material from a slit. An applicator characterized in that an adhesive rotation roll for removing deposits adhering to the flexible support is disposed upstream of the die. 2. A plurality of the adhesive rotation rolls are arranged on a rotating member that rotates in an arc shape, and each of the adhesive rotation rolls rotates and comes into contact with the flexible support alternately. The coating device according to claim 1. 3. The adhesive rotation rolls are respectively arranged on a plurality of elevating members which are alternately moved up and down, and these adhesive rotation rolls are alternately contacted with a flexible support. 1. The coating apparatus according to 1.