JPH05285437A - Method for applying coating liquid and coater - Google Patents

Abstract

(57) [Abstract] [Purpose] A coating solution applied from an extrusion type coating head onto a base film to make the flow of the coating solution spiral inside the extrusion type coating head. From the coating liquid outflow slit via the reservoir
The composition is discharged onto a film, and uniform coating can be performed under a wide range of coating conditions without causing uneven thickness or coating stripes. A coating liquid coating method using an extrusion type coating head and an apparatus therefor are provided with a coating liquid reservoir for spirally flowing a coating liquid in the extrusion type coating head, and the coating liquid is coated with the coating liquid. A method and apparatus for applying a coating solution, in which the coating solution is discharged from a coating solution outflow slit through a reservoir onto a base film so that uniform coating can be performed under a wide range of coating conditions without causing uneven thickness or coating stripes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating liquid coating method using an extrusion type coating head and an apparatus therefor, and more specifically, it uses an extrusion type coating head to coat a coating liquid over a wide range of coating conditions. The present invention relates to a method and apparatus for uniformly coating without causing unevenness in thickness and coating stripes.

[0002]

2. Description of the Related Art Generally, various aqueous solutions or resin solutions, or various dispersions prepared by mixing and dispersing various powders in a dispersion medium such as water or an organic solvent are coated on a continuously moving base film. As a method, a gravure method and a reversing method
Indirect coating methods such as a scroll method and a kiss coat method have been widely put into practical use. However, in these indirect coating methods, the coating solution is exposed to the air, so there is a problem as a coating method of the coating solution in which property changes easily occur. This tendency is remarkable in the magnetic coating liquid and the like prepared by mixing and dispersing in 2., the property changes due to the waterfall in the air, and the quality of the coating film is likely to deteriorate. Therefore, in recent years, direct coating methods such as an extrusion method have been adopted in place of these indirect coating methods (JP-A-57-84771, JP-A-58-104666,
According to this extrusion method, since the coating solution is completely sealed until it is applied on the base film, it is possible to suppress the change in the properties of the coating solution as much as possible. In addition, it is easy to deal with the speeding up of the coating process.

[0003]

However, in the conventional extrusion method, as shown in FIGS. 7 and 8, the coating liquid 7 is aligned with the center of the cross section of the coating liquid reservoir 2c.
The coating solution injection port 3c for injecting
The coating liquid 7 injected into c is discharged from the slit 6c at the shortest distance as shown by the arrow E, the amount of coating liquid that can be applied and the range of viscosity are narrow, and the coating liquid flowing in the coating liquid outflow slit is However, it becomes difficult to flow due to an increase in pressure loss toward the end portion in the coating width direction, and especially in the wall surface portion,
The friction loss becomes maximum and there is almost no flow of the coating liquid and the liquid stagnates. On the other hand, in the central portion in the coating width direction, the pressure loss becomes minimum and the coating liquid easily flows. For this reason,
The shape distribution in the width direction of the coating film is thicker in the center part and thinner as it goes to the end part, especially uneven coating amount in the width direction tends to occur, and it is difficult to obtain a uniform and high-quality coating film. .. Further, when a sufficient amount of the coating liquid is not supplied to the extrusion type coating head, the flow of the coating liquid at the end of the coating liquid outflow slit is further deteriorated, and coating in the entire coating width direction becomes impossible.

[0004]

SUMMARY OF THE INVENTION The present invention has been made as a result of various studies in view of the above-mentioned current situation, and a coating solution on a base film is continuously moved by using an extrusion type coating head. When applying to the
The coating liquid reservoir provided in the John type coating head makes the flow of the coating liquid injected from the coating liquid inlet into a spiral shape, so that the coating liquid can be applied to the end portion and the wall surface portion of the coating liquid reservoir in the coating width direction. Flow smoothly without stagnation, and the coating liquid is uniformly discharged from the coating liquid outflow slit over the entire width of the base film in the coating width direction, so that there is no uneven thickness or coating streaks. It is possible to perform various coatings, and in particular, to obtain a high quality coating film having a uniform shape distribution in the width direction of the coating film.

An example of a coating liquid coating apparatus used in the present invention will be described below with reference to the drawings. Figure 1
And FIG. 2 shows the extruder used in the present invention.
An example of a John type coating head is shown. The extrusion type coating head 1 is provided with a cylindrical coating liquid reservoir 2 inside, and a coating liquid injection port 3 communicating with the coating liquid reservoir 2 is applied. The liquid pool 2 is bent and provided so as to communicate with the opening in the tangential direction of the lower end inner peripheral wall, and the coating head downstream end 4 and the coating head upstream end 5 are arranged above and below the coating head downstream end 4 and the coating head upstream. A coating liquid outflow slit 6 is formed between the end 5 and the end 5.

Thus, the coating liquid 7 injected from the coating liquid inlet 3 into the coating liquid reservoir 2 is opened in the tangential direction of the inner peripheral wall of the lower end of the coating liquid reservoir 2 and is applied from the center of the cross section of the coating liquid reservoir 2. Since the liquid is injected from the coating liquid injection port 3 which is eccentric in the discharging direction, a spiral flow occurs in the coating liquid reservoir 2 as indicated by arrow B.

Therefore, the coating liquid 7 flows smoothly without stagnation even at the end portion and the wall surface portion of the coating liquid reservoir 2 in the coating width direction, and continuously runs from the coating liquid outflow slit 6.
The coating liquid 7 is uniformly discharged onto the spray film 8 in the entire coating width direction. As a result, even if the coating conditions such as the viscosity, the coating speed, and the coating amount of the coating liquid 7 are changed, uniform coating can be performed without causing unevenness in thickness or coating streaks in the entire coating width direction. A high-quality coating film 9 having a uniform shape distribution in the width direction is formed. Formation of such a high quality coating film 9 is particularly effective when the coating film 9 is thin, and
A high-quality coating film 9 having a uniform shape distribution in the width direction of 0.1 to 1 μm can be easily obtained.

FIGS. 3 and 4 show another example of the extrusion type coating head used in the present invention. The extrusion type coating head 1a is
A cylindrical coating liquid inlet 3a communicating with the coating liquid reservoir 2a
Is formed in the same manner as the extrusion-type coating head 1 shown in FIGS. 1 and 2, except that it is provided eccentrically from the center of the cross section of the coating liquid reservoir 2a in the direction opposite to the direction in which the coating liquid is discharged. ing.

However, also in the extrusion type coating head 1a shown in FIGS. 3 and 4, the coating liquid 7 injected from the coating liquid inlet 3a into the coating liquid reservoir 2a is
As shown by the arrow C, the coating solution pool 2a becomes spiral, and the same effect as that of the extrusion-type coating head 1 shown in FIGS. 1 and 2 is exhibited, and uniform coating is performed in the entire coating width direction. A high quality coating film 9 having a uniform shape distribution in the width direction of the coating film is formed.

FIGS. 5 and 6 show another example of the extrusion type coating head used in the present invention. The extrusion type coating head 1b communicates with the coating liquid reservoir 2b. A columnar coating liquid injection port 3b is provided so as to be aligned with the center of the cross section of the coating liquid reservoir 2b, and a flow adjusting plate that adjusts the direction of the flow of the coating liquid 7 to the communicating portion of the coating liquid reservoir 2b with the coating liquid inlet 3b. It is configured in the same manner as the extrusion-type coating head 1 shown in FIGS. 1 and 2, except that 10 is additionally provided.

Therefore, in the extrusion type coating head 1b shown in FIGS. 5 and 6, the coating liquid 7 is used.
The coating liquid 7 injected into the coating liquid reservoir 2b from the coating liquid inlet 3b by the flow adjusting plate 10 for adjusting the direction of the flow of the coating liquid 7
However, as shown by the arrow D, it becomes spiral in the coating liquid reservoir 2b, and the same effect as that of the extrusion-type coating head 1 shown in FIGS. 1 and 2 is exhibited, and uniform coating is achieved in the entire coating width direction. As a result, a high-quality coating film 9 having a uniform shape distribution in the width direction of the coating film is formed.

The shape of the coating liquid reservoir is not limited to the above embodiment, but may be various shapes. For example, the cross section may be semicircular, fan-shaped or polygonal instead of circular.

[0013]

EXAMPLES Next, examples of the present invention will be described. Example 1 Co-deposited γ-Fe ₂ O ₃ (long axis diameter 0.4 μm, short axis diameter 0.05 500 parts by weight μm, coercive force 600 oersted) Nitrocellulose 50 〃 Pandex T-5250 (Dainippon Ink and Chemicals Incorporated) Made; 30〃 Polyurethane resin) Coronet L (Nippon Polyurethane Industry Co., Ltd .; trifunctional low 20〃 Molecular weight isocyanate compound) Mogal L (Cabot Co .; carbon black) 10〃 Myristic acid 3〃 Butyl stearate 2 〃 Methyl isobutyl ketone 720 〃 Toluene 720 〃 This composition was mixed and dispersed with a ball mill for 72 hours to prepare magnetic paints of Samples 1 to 9 having respective viscosities shown in Table 1 below. As shown in FIGS. 1 and 2, the magnetic paint is communicated with a cylindrical coating liquid reservoir 2 through a coating liquid inlet 3 which is bent so as to open in the tangential direction of the inner peripheral wall of the lower end of the coating liquid reservoir 2. Using the extrusion-type coating head 1 thus prepared, each of the coating liquid injection amounts shown in Table 1 below was discharged, coated on the polyester film 8 and dried to give Samples 1 to 9
Magnetic layer 9 was formed.

[0014]

Example 2 Samples 1 to 1 of each viscosity shown in Table 1 were prepared in the same manner as in Example 1.
9 magnetic paints were prepared. Then, instead of the extrusion-type coating head 1 used in Example 1, the coating liquid is discharged from the center of the cross section of the coating liquid reservoir 2a into a cylindrical coating liquid reservoir 2a as shown in FIGS. 3 and 4. These magnetic coating materials were prepared in the same manner as in Example 1 except that an extrusion-type coating head 1a was used, which was eccentric in the opposite direction to the cylindrical coating liquid injection port 3a and was made to communicate with the coating liquid injection port 3a. Samples 1 to 1 were coated with each coating solution injection amount shown in 1 and dried.
The magnetic layer 9 of No. 9 was formed.

Example 3 In the same manner as in Example 1, Samples 1 to 1 having the respective viscosities shown in Table 1 were prepared.
9 magnetic paints were prepared. Then, instead of the extrusion-type coating head 1 used in Example 1, as shown in FIG. 5 and FIG. 6, the coating liquid reservoir 2b having a cylindrical shape is provided with the coating liquid injection port 3b having a cylindrical shape. Flow adjusting plate 10 for adjusting the flow direction of the coating liquid to the communicating portion of the coating liquid reservoir 2b and the communicating portion of the coating liquid injection port 3b.
These magnetic coating materials were prepared in the same manner as in Example 1 except that the extrusion-type coating head 1b additionally provided was used.
The magnetic layers 9 of Samples 1 to 9 were formed by applying the respective coating liquid injection amounts shown in Table 1 and drying.

Comparative Example 1 In the same manner as in Example 1, Samples 1 to 1 having the respective viscosities shown in Table 1 were prepared.
9 magnetic paints were prepared. Then, instead of the extrusion-type coating head 1 used in Example 1, as shown in FIGS. 7 and 8, a cylindrical coating liquid reservoir 2c was provided with a cylindrical coating liquid inlet 3c. Extrusion-type coating head 1c communicated with the center of the cross section of the
In the same manner as in Example 1 except that the above was used, these magnetic coating materials were applied at the injection amounts of the respective coating liquids shown in Table 1 above and dried to form the magnetic layers 9 of Samples 1 to 9. In the case of Samples 1 and 6, the magnetic paint did not flow out in the coating width direction and the formation of the magnetic layer 9 was incomplete.

In each of the examples and comparative examples, the coating thickness unevenness in the coating width direction of the magnetic layer obtained by coating the magnetic coating material was measured by a fluorescent X-ray micrometer film thickness meter (manufactured by Seiko Electronics Co., Ltd .; S
FT-7105, collimator spot diameter 1.0 mm), and the deviation from the average film thickness was shown as a percentage. Table 2 below shows the results.

[0019]

[0020]

As is clear from Table 2 above, the magnetic layer obtained by the coating apparatus and coating method of the present invention (Example 1)
3 to 3) have smaller coating thickness unevenness than the magnetic layer obtained by the conventional coating method (Comparative Example 1). Therefore, according to the coating apparatus and the coating method of the present invention, the viscosity is different. It can be seen that even if the coating conditions are changed over a wide range using the above paint, good coating can be performed without causing uneven coating thickness, a high quality coating film can be obtained, and it can greatly contribute to productivity improvement. ..

[Brief description of drawings]

FIG. 1 is an extruder showing an example of a coating apparatus of the present invention.
It is a schematic sectional drawing of a John type coating head.

2 is a cross-sectional view of the extrusion-type coating head shown in FIG. 1 taken along the line AA.

FIG. 3 is a schematic sectional view of an extrusion-type coating head showing another example of the coating apparatus of the present invention.

FIG. 4 is a cross-sectional view taken along the line AA of the extrusion-type coating head shown in FIG.

FIG. 5 is a schematic sectional view of an extrusion-type coating head showing another example of the coating apparatus of the present invention.

FIG. 6 is a cross-sectional view taken along the line AA of the extrusion-type coating head shown in FIG.

FIG. 7 is a schematic cross-sectional view showing an example of a conventional extrusion-type coating head.

8 is a cross-sectional view taken along line AA of the extrusion-type coating head shown in FIG.

[Explanation of symbols]

 1,1a, 1b Extrusion type coating head 2,2a, 2b Coating liquid reservoir 3,3a, 3b Coating liquid injection port 4,4a, 4b Coating head downstream end 5,5a, 5b Coating head upstream end 6,6a, 6b Coating liquid outflow slit 7 Coating liquid (magnetic paint) 8 Base film (polyester film) 10 Flow control plate

Claims (4)

[Claims] 1. When applying a coating solution onto a base film that continuously moves by using an extrusion type coating head, a coating solution injection port is provided in a coating solution reservoir provided in the extrusion type coating head. It is characterized in that the flow of the coating liquid injected from the device is made into a spiral shape, and then the coating liquid that has become a spiral flow in the coating liquid reservoir is discharged from the tip of the coating liquid outlet slit and is applied onto the base film. How to apply the coating liquid 2. A coating apparatus for coating a coating film on a base film which continuously moves by using an extrusion coating head, wherein the coating liquid is injected into the extrusion coating head through a coating liquid injection port. A coating liquid reservoir that makes the flow of the coating liquid spiral is provided, and the coating liquid that has become a spiral flow in the coating liquid reservoir is discharged from the coating liquid outflow slit to apply the coating liquid on the base film. Coating device 3. An eccentricity of a coating solution reservoir for making the flow of the coating solution spiral, forward and backward from a center of a cross section of the coating solution reservoir in a direction in which the coating solution is discharged, from a coating solution injection port communicating with the coating solution reservoir. 3. A coating solution reservoir which is made to inject a coating solution from an eccentric coating solution inlet to form a spiral flow.
Coating liquid coating device 4. A coating liquid reservoir for making the flow of the coating liquid spiral, and a flow adjusting plate for adjusting the direction of the coating liquid flow is attached to a communicating portion of the coating liquid inlet of the coating liquid reservoir. The coating liquid coating device according to claim 2, wherein the plate is a coating liquid reservoir that makes the flow of the coating liquid injected from the coating liquid inlet into the coating liquid reservoir spiral.