JP2000202842A - Method and apparatus for manufacture of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a film-making speed and a productivity by preventing air bite from being generated by a method wherein fluctuation of a landing point on a transfer cast surface of a resin film extruded from a slit clearance of a mouthpiece is controlled by at least two suction means which are different from each other. SOLUTION: A suction nozzle 6 for generating a negative pressure region 5 coming in contact with a resin film 2 is arranged to a rear face side of a mouthpiece 1, i.e., an upstream side in a transfer direction from a landing point 4 onto a cast face 3a on a rotary drum 3 of the resin film 2. A means for applying a liquid onto the cast face 3a is arranged to a further upstream side in a transfer direction, which comprises a spray nozzle 10 for applying a solvent equal in quality to the solvent contained in the resin film 2. Then, the resin film 2 is restricted so as to be stably landed at a specific landing point 4 by a negative pressure region 5 generated by the suction nozzle 6 to restrict fluctuation of the landing point 4. Further, the resin film 2 is made easy to be bonded by the solvent which is applied by the spray nozzle 10, and local fluctuation of the landing point 4 is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a film in which a molten resin film or a solution resin film obtained by dissolving a resin in a solvent or a solution is extruded from a slit gap of a die onto a moving cast surface.

[0002]

2. Description of the Related Art Conventionally, there has been known a manufacturing method in which a molten resin or a solution resin is extruded into a sheet shape from a slit gap of a die, brought into close contact with a cast surface, and then cooled or dried to form a resin film. In the production of such a resin film, it is determined whether the adhesion point (landing point) of the resin film discharged from the base to the casting surface is stable.
It has a fundamental effect on subsequent processes and is an important factor in determining product quality.

[0003] That is, if this landing point is unstable,
For example, a phenomenon occurs in which air is caught between the film and the casting surface from a position where the landing point is most delayed (hereinafter, this phenomenon is referred to as "air biting"). When this air biting occurs, there are problems such as uneven thickness of the film surface and stress concentration at the air biting portion in the subsequent stretching process, causing the film to break. This air biting phenomenon becomes more remarkable as the film forming speed increases, which hinders improvement in productivity.

[0004] Such a change in the landing point of the resin film on the moving cast surface, which causes air biting, occurs as shown in, for example, FIGS. 6 and 7. In FIG. 6, when the resin film 103 is cast from the base 101 onto the moving cast surface 102, the width direction of the base 101 at the landing point (the resin film 10).
The landing line 104, which is a locus in the width direction of No. 3), fluctuates in the width direction. When the variation width δ1 increases, air bite occurs locally. The variation width δ1 is particularly problematic in the product portion 105 in the center in the width direction of the resin film 103, and it is difficult to confirm the landing point in the non-product portions 106 which are the ear portions on both sides. Often not. FIG. 7 shows how the landing point 114 fluctuates with time in the product section when the resin film 113 is cast from the base 111 onto the movable cast surface 112. When the fluctuation width δ2 becomes large, the variation width δ2 also increases. Air biting occurs. The variation shown in FIG. 6 and the variation shown in FIG. 7 may occur in combination.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively suppress the above-mentioned fluctuation of the landing point of the resin film, prevent the occurrence of air bite, improve the film forming speed, and improve the productivity. Is to improve.

[0006]

In order to solve the above-mentioned problems, a method of manufacturing a film according to the present invention is characterized in that a resin film extruded from a slit gap of a die is brought into close contact with a moving cast surface, and the film is moved with the movement of the cast surface. The method for producing a film to be sent downstream is characterized in that a variation in the point of attachment of the resin film to the casting surface is suppressed by two or more different adhesion means.

Further, the film manufacturing apparatus according to the present invention is a film manufacturing apparatus in which a resin film extruded from a slit gap of a die is brought into close contact with a moving cast surface and is sent downstream along with the movement of the cast surface. As a close contact means to suppress the fluctuation of the landing point on the cast surface,
It is characterized by having two or more means different from each other.

In other words, two or more contacting means, which were conventionally provided only once, are provided in combination, whereby the variation of the contact point of the resin film is suppressed more effectively. is there. Also, by making the two or more contacting means an optimal combination, for example, by making one contacting means a main contacting means and the other contacting means a subordinate contacting means, Thus, the effect of suppressing the variation of the landing point can be obtained effectively.

As the above-mentioned adhesion means, any of means for suppressing the variation of the landing point in the width direction of the resin film, means for suppressing the variation over time of the landing point, and a combination thereof are used. Can be configured. The variation of the landing point differs depending on the distance between the slit gap of the base and the casting surface, and the variation of the landing point is 5 mm or less when the distance between the slit gap of the base and the casting surface is less than 10 mm. When the distance between the slit gap of the base and the casting surface is 10 mm or more, it is preferable to suppress the variation of the landing point to 10 mm or less. The variation of the landing point is intended for the variation in the product portion at the center in the resin film width direction as shown in FIG.

As a more specific mode of the contacting means, one of the contacting means is provided with a suction nozzle which is located on the upstream side in the moving direction of the casting surface from the landing point and generates a negative pressure area directly in contact with the resin film. Is preferred.

When one of the contacting means is constituted by such a suction nozzle, and when the resin film is a solution film, the other one of the contacting means is applied by liquid application for applying a liquid to the cast surface. Means can be configured. For example, a solvent application unit that applies a solvent equivalent to the solvent contained in the solution film to the cast surface can be used. Alternatively, when the resin film is made of a molten film or a solution film, a negative pressure region which is located on the upstream side of the casting surface moving direction from the landing point and which is not directly in contact with the resin film is generated by another one of the adhesion means. It can also be configured as a suction nozzle. Alternatively, the other one of the adhesion means may be configured as an electrostatic load means for applying an electrostatic charge to the resin film. Furthermore, another one of the contacting means may be constituted by an air knife provided above the landing point or downstream of the landing point in the direction of movement of the casting surface. Further, two or more of these other contacting means may be used in combination.

The moving cast surface may be formed by either a rotating belt or a rotating drum.

In such a method and apparatus for producing a film according to the present invention, by using two or more contacting means in combination, for example, the main contacting means is a suction nozzle provided on the back side of the base, and in addition to this, By providing another contacting means as described above, the landing point is basically stabilized so that the fluctuation is not increased by the main contacting means. It is possible to further suppress the variation of the portion or the variation over time. Therefore, the variation of the landing point can be greatly reduced both in the width direction of the resin film and over time, and by stabilizing the landing point (by making the landing point substantially constant), Biting is prevented, and a film having improved quality without unevenness in thickness can be manufactured, and a film can be formed at a higher speed. Further, since a more remarkable effect appears in a thin film in which landing point variation is liable to occur, the film to be produced can be further thinned.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a film manufacturing apparatus according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a solution resin film 2 containing a solvent (for example, a resin film in a solution film formation of polyamide or polyimide resin).
Is shown, and the discharged resin film 2 has
It is cast on a moving cast surface 3a formed by the surface of the rotating cooling drum 3.

On the back side of the base 2, that is, on the upstream side in the direction of movement of the casting surface from the point of attachment 4 of the resin film 2 to the casting surface 3a, there is a negative pressure area adjacent to the base 2 and in direct contact with the resin film 2. 5 is provided. The suction nozzle 6 has a suction port 7 and a decompression chamber 8, and the inside of the decompression chamber 8 is controlled to a predetermined degree of decompression by air suction by a blower 9. This suction nozzle 6
Constitute the main contacting means.

In this embodiment, a liquid applying means for applying a liquid to the casting surface 3a is provided on the upstream side of the suction nozzle 6 in the direction of movement of the casting surface as a subordinate contact means.
In the present embodiment, the liquid application means is constituted by a spray nozzle 10 as a solvent application means for applying a solvent equivalent to the solvent contained in the solution film 2 (that is, the same or the same type) to the casting surface 3a. I have.

The spray nozzle 10 may extend over substantially the entire width of the resin film 2 in the width direction of the resin film 2. Alternatively, if the location where the landing point 4 becomes unstable is known in advance, it may be provided at the specific position in the width direction.

In the production of a film using such a production apparatus, the resin film 2 immediately before the landing point 4 is stabilized at the predetermined landing point 4 by the negative pressure region 5 generated by the suction nozzle 6 as the main contact means. Thus, the landing point 4 is suppressed from fluctuating in the width direction of the resin film 2 and also over time.

Then, the solvent applied to the casting surface 3a from the spray nozzle 10, which is a close contact means,
The resin film 2 is more easily adhered to the portion at the landing point 4 and the portion immediately adjacent to the portion, and the local fluctuation of the landing point 4 can be suppressed to be smaller.

As a result, as a whole, the fluctuation of the landing point 4 is greatly reduced locally and over time, so that inconvenience such as air biting is prevented, and the quality of the film is improved. At the same time, higher-speed film formation and thinning can be achieved.

FIG. 2 shows a film manufacturing apparatus according to a second embodiment of the present invention. In the present embodiment, as compared with the first embodiment, as a close contact means, instead of the spray nozzle 10, the suction nozzle 6 is in direct contact with the resin film 2 at a position opposite to the base 1. Negative pressure area 11 not
Is provided. The suction nozzle 12 has a suction port 13 that opens to face the casting surface 3a and a decompression chamber 14. The inside of the decompression chamber 14 is controlled to a predetermined degree of decompression by suction of air by a blower 15. It has become. Other configurations are in accordance with the first embodiment.

In the production of a film using such a production apparatus, the resin film 2 immediately before the landing point 4 is stabilized at the landing point 4 by the negative pressure region 5 generated by the suction nozzle 6 as the main contact means. At this time, by further creating a negative pressure region 11 on the back side,
The fluctuation in the negative pressure region 5 is suppressed to be smaller. When the fluctuation of the negative pressure region 5 is suppressed, the fluctuation of the landing point 4 is correspondingly suppressed, and as a result, the fluctuation of the landing point 4 is significantly suppressed locally and over time. Become. Therefore, the occurrence of inconvenience such as air biting is prevented, the quality of the film is improved, and a higher-speed film formation and a thinner film can be realized.

FIG. 3 shows a film manufacturing apparatus according to a third embodiment of the present invention. In the present embodiment, as compared with the first embodiment, the auxiliary contacting means is constituted by static electricity applying means 21 provided above the landing point 4 and for applying an electrostatic charge to the resin film 2. Static electricity applying means 21
Consists of, for example, a conductive wire or a conductive knife edge to which a high DC voltage is applied. Other configurations are first
According to the embodiment.

In the film production using such a production apparatus, the resin film 2 immediately before the landing point 4 is stabilized at the landing point 4 by the negative pressure region 5 generated by the suction nozzle 6 as the main contact means. In addition, the resin film 2 is more strongly adhered to the casting surface 3a at the landing point 4 due to the electrostatic charge given by the static electricity applying means 21, and the variation of the landing point 4 is suppressed to be smaller. . As a result, the fluctuation of the landing point 4 can be greatly reduced both locally and over time. Therefore, the occurrence of inconvenience such as air biting is prevented, the quality of the film is improved, and a higher-speed film formation and a thinner film can be realized.

FIG. 4 shows a film manufacturing apparatus according to a fourth embodiment of the present invention. In this embodiment, as compared with the first embodiment, the auxiliary contact means is constituted by an air knife 31 provided above the landing point 4 or downstream of the landing point 4 in the direction of movement of the casting surface. Clean air (or gas) whose pressure is adjusted is linearly blown from an appropriate pressure air source (not shown) to the air knife 31. Other configurations are in accordance with the first embodiment.

In the production of a film using such a production apparatus, the resin film 2 immediately before the landing point 4 is stabilized at the landing point 4 by the negative pressure area 5 generated by the suction nozzle 6 as the main contact means. However, in addition, the air knife 31 linearly blows air to the landing point 4.
Alternatively, the resin film 2 is pressed against the cast surface 3a at a position immediately adjacent thereto, and the landing point 4 is regulated to a desired position. As a result, the fluctuation of the landing point 4 can be greatly reduced both locally and over time. Therefore, the occurrence of inconvenience such as air biting is prevented, the quality of the film is improved, and a higher-speed film formation and a thinner film can be realized.

In the first to fourth embodiments, the case where the movable casting surface 3a is formed by the rotary drum 3 has been described. However, the present invention is not limited to this, and the movable casting surface 3a is formed by a belt that rotates. The same applies to devices.

For example, an embodiment corresponding to the above-described second embodiment is shown in FIG. 5 as a fifth embodiment. In the present embodiment, the moving cast surface 41a is
It is formed by a belt 41 that is wound around and driven between three belts. This embodiment is suitable for solution casting. Other configurations and operations are similar to those of the second embodiment. Needless to say, the same contact unit structure as in the first, third, and fourth embodiments described above is also applicable to the circulating belt type apparatus.

Further, in each of the above-described embodiments, an example is shown in which two different contact means are provided, but a combination of three or more may be provided.

[0030]

As described above, according to the method and apparatus for producing a film of the present invention, the resin film is brought into close contact with the cast surface by using two or more different contact means. The fluctuation of the landing point on the vehicle is greatly suppressed, and a stable cast state in which the fluctuation is suppressed locally and over time can be achieved. as a result,
It is possible to prevent the occurrence of inconveniences such as air biting, thereby improving the quality of the film, improving the film forming speed, and promoting the thinning of the film.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a film manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a film manufacturing apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a film manufacturing apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a film manufacturing apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a film manufacturing apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a schematic perspective view showing how a landing point changes in a conventional film manufacturing apparatus.

FIG. 7 is a schematic cross-sectional view showing another variation of the landing point in the conventional film manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Resin film 3 Rotary drum 3a Moving cast surface 4 Landing point 5 Negative pressure area 6 Suction nozzle 10 Spray nozzle 11 Negative pressure area 12 Suction nozzle 21 Static electricity applying means 31 Air knife 41 Circulating belt 41a Moving cast surface

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hidetoshi Okagi 1-1-1 Sonoyama, Otsu City, Shiga Prefecture F-term in the Shiga Plant of Toray Industries Co., Ltd. 4F205 AA29 AA40 AC05 AG01 AR07 GA07 GB02 GC02 GC07 GE01 GF01 GF23 GF24 GF30 GF46 GN04 GN24

Claims (14)

[Claims] 1. A method for producing a film in which a resin film extruded from a slit gap of a die is brought into close contact with a moving cast surface and fed downstream along with movement of the cast surface. A method for producing a film, characterized in that a change in a point of landing of a film on a cast surface is suppressed. 2. The film manufacturing method according to claim 1, wherein a variation in the width direction of the landing point in the resin film width direction is suppressed by the adhesion means. 3. The method for producing a film according to claim 1, wherein a time-dependent variation of the landing point is suppressed by a contact means. 4. When the distance between the slit gap of the base and the casting surface is less than 10 mm, the variation of the landing point is suppressed to 5 mm or less, and the distance between the slit gap of the base and the casting surface is 1 mm.
The method for producing a film according to any one of claims 1 to 3, wherein a variation of a landing point is suppressed to 10 mm or less when the distance is 0 mm or more. 5. A film manufacturing apparatus in which a resin film extruded from a slit gap of a die is brought into close contact with a moving casting surface and is sent downstream along with the movement of the casting surface. An apparatus for producing a film, comprising two or more different means as adhesion means for suppressing the film. 6. The film manufacturing apparatus according to claim 5, wherein the adhesion unit suppresses a variation in the width of the landing point in the resin film width direction. 7. The film manufacturing apparatus according to claim 5, wherein the close contact means suppresses a change over time of the landing point. 8. One of the contacting means is a suction nozzle which is located on the upstream side in the moving direction of the casting surface from the landing point and generates a negative pressure region which is in direct contact with the resin film.
An apparatus for producing a film according to any one of the above. 9. The film manufacturing apparatus according to claim 8, wherein the resin film is made of a solution film, and another one of the adhesion means is a liquid applying means for applying a liquid to the cast surface. Another one of the adhesion means is a suction nozzle which is located upstream of the landing point in the direction of movement of the casting surface and generates a negative pressure region which is not directly in contact with the resin film.
An apparatus for manufacturing a film according to claim 8. 11. The film manufacturing apparatus according to claim 8, wherein another one of the adhesion means comprises an electrostatic application means for applying an electrostatic charge to the resin film. 12. The film manufacturing apparatus according to claim 8, wherein the other one of the contacting means comprises an air knife provided above the landing point or downstream of the landing point in the direction of movement of the casting surface. 13. The film manufacturing apparatus according to claim 5, wherein the movable cast surface is formed by a circling belt. 14. The film manufacturing apparatus according to claim 5, wherein the moving cast surface is formed by a rotating drum.