JP2013223947A - Apparatus and method for annealing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus by which the flatness of a film after annealing is improved to a uniform favorable condition in an annealing treatment for flattening the surface of the film even if the distortion of the film before annealing in a width direction is generated nonuniformly.SOLUTION: An annealing apparatus has a heating roll for annealing a moving roll film in a surface-contacting state. The heating roll has a plurality of embedded heaters provided circumferentially on a plane orthogonal to the axis of the heating roll in the inner vicinity of the outer surface of a cylindrical heating roll, and the surface temperature distribution of the area near the end spacing from the center of the axial direction of the heating roll is controlled separately from the other area.

Description

  The present invention relates to an annealing process for surface correction of a film.

  Currently, processing using various plastic films is used in many fields. In particular, anti-reflection films, etc. used for packaging films, transfer ribbon films, display devices, etc., which are mass-produced by printing and coating on the film surface, are suitable for roll-to-roll manufacturing and are inexpensive to produce. Is possible. The roll-to-roll production refers to a series of steps in which various treatments are performed on the film surface where the roll-wound film is unwound, and then continuously wound on other rolls to return to the roll-wound state. In production, it is desirable that the surface of these films is smooth and has no film thickness unevenness or surface waviness.

However, even if film formation processing is performed using a resin material with good surface smoothness and coating conditions to prevent foreign material adhering to the surface in a clean environment, distortion and warpage that occur during film formation processing and surface treatment It may remain in the form of swells. Conventionally, as a means for solving the above problems, it has been generally performed to correct the surface of a film.
For example, in the production process of an antireflection film using a roll-to-roll process including a coating process, the surface to be coated must be flat when the unwinding process, the coating process, the drying / curing process, and the winding process are sequentially performed. Thus, good coating quality cannot be obtained. For this reason, the film surface is previously flattened before coating by performing a film correction process between the unwinding process and the coating process.
In the film correction process, the film that is transported from the unwinding device is heated and tension is applied or a smooth roller is pressed to remove distortion, so that a flat surface is created by so-called annealing treatment. Is.
Patent Document 1 proposes a method for producing an optical film in which the film correction process is performed to improve film thickness unevenness and flatness.

FIG. 2 is a schematic diagram of a main part for explaining an example of the configuration of a conventional annealing apparatus. The annealing treatment apparatus 10 feeds the film 1 unwound from a winding roll (not shown) in the direction of the solid line arrow, and rotates along the outer peripheral surfaces of the heating roll 2 and the heating roll 3 rotated at the same peripheral speed as the film transport speed. While keeping a certain tension and contacting the film, the film is run in this order and annealed. Thereafter, the film 1 is continuously discharged in the direction of the solid line at the bottom and is wound on another winding roll (not shown). The heating roll 2 and the heating roll 3 both have a heating mechanism inside to increase the temperature of the outer peripheral surface, and heat from the contact surface of the film along the outer peripheral surface.
On the other hand, as shown by the upper and lower two block arrows in the figure, the outer surface of the film 1 along the outer peripheral surface of the heating roll can be heated with hot air from outside the heating roll. Uniform heating from both sides of the film is achieved by heating the film 1 with a heating roll and hot air by exchanging the heating surfaces of the film at two locations, upper and lower.

FIG. 3 is a schematic diagram for explaining an example of a heating mechanism of a conventional heating roll.
A heating roll having a heating medium inlet 21 at one of the cylindrical ends of the heating roll 2 and a heating medium outlet 22 at the opposite cylindrical end is provided. In the direction of the block arrow, the heating medium is allowed to pass through the heating roll 2 and the passage inside the heating roll is devised so that the heating medium flows along a path through which heat is easily transmitted to the roll surface. As the heating medium, hot water and water vapor generated by heating externally can be circulated and reused. Moreover, the path | route of a heating medium is equally arrange | positioned inside a heating roll so that the whole roll can be heated uniformly.

JP 2010-99911 A

In the above-described annealing apparatus, by using a heating roll that can uniformly heat the entire roll, the film conveyed along the outer peripheral surface of the heating roll can be heated uniformly. On the other hand, in a film to be annealed, distortion and warpage of the film remaining in the form of surface waviness or the like do not necessarily occur uniformly or randomly over the entire surface.
FIG. 4 is an example showing a general state of distortion of the film to be annealed on the heating roll, and (a) is a schematic diagram of the state during the annealing process in which the film is stacked on the heating roll. Yes, (b) is an enlarged schematic view of the state of occurrence of distortion by position in the width direction of the film. There is a tendency that the state of occurrence of wavy distortion differs depending on the position in the width direction of the film. That is, both end portions A and C in the width direction of the film have large undulations, and in B, which is a central region in the width direction of the film, the undulations are small or almost no undulations.

  When the entire heating roll 2 is used with uniform temperature control as in the prior art for the film 1 in the above-described situation, an area having a large strain, for example, in the figure, is controlled when controlled on a relatively low temperature side. The annealing effect at A and C is insufficient and correction is not completed. Further, when the heating roll 2 is controlled on the relatively high temperature side, heating in a region with a small distortion, for example, B in the figure becomes excessive. In other words, extra heat is applied to the region B that requires only low-temperature correction, which causes new troubles such as heat wrinkles.

  The present invention is proposed in view of the above-mentioned problems, and the problem to be solved by the present invention is that in the annealing process for correcting the surface of the film, the occurrence of distortion in the width direction of the film before the annealing process occurs. The object is to provide a means for improving the flatness of the film after annealing to a uniform good state even if it is not uniform.

  As a means for solving the above-mentioned problems, the invention according to claim 1 is an annealing apparatus having a heating roll for annealing a winding film in running in a surface contact state, wherein the heating roll is a heating roll. Surface temperature distribution in a region closer to the end than the center in the axial direction of the heating roll, having a plurality of embedded heaters provided circumferentially on a plane perpendicular to the axis of the heating roll, near the inside of the outer surface of the cylindrical heating roll The film annealing apparatus is characterized in that it can be controlled separately from other regions.

  The invention according to claim 2 is characterized in that the heating roll has uniform heating means for the entire heating roll provided with a pipe through which the temperature-controlled fluid passes. An annealing apparatus.

  The invention according to claim 3 is characterized in that the plurality of embedded heaters are provided at axial positions of the heating roll corresponding to different widths of the winding film to be annealed. It is an annealing treatment apparatus of the described film.

  The invention according to claim 4 is a film annealing method using the annealing apparatus according to any one of claims 1 to 3, wherein a heater selected from a plurality of embedded heaters is independently provided. By controlling and using, the surface temperature distribution of the area | region near an edge part from the center of the axial direction of a heating roll is controlled to the high temperature side, It is a film annealing process method characterized by the above-mentioned.

  The invention according to claim 5 is characterized in that the surface temperature in the roll circumferential direction of the heating roll is made uniform, and the heating roll is rotated at the same circumferential speed as the conveyance speed of the winding film to be annealed. The film annealing method according to claim 4.

  The present invention relates to an annealing apparatus having a heating roll for annealing a winding film in running in a surface contact state, wherein the heating roll includes an embedded heater provided circumferentially on a plane perpendicular to the axis of the heating roll. Since there are multiple near the inside of the outer surface of the cylindrical heating roll, the surface temperature distribution in the area closer to the end than the center in the axial direction of the heating roll can be controlled separately from other areas. To provide means for improving the flatness of a film after annealing to a uniform and good condition even when the generation of distortion in the width direction of the film before annealing is not uniform in the annealing treatment for surface correction. Can do.

It is a front schematic diagram for demonstrating an example of a structure of the heating roll provided in the annealing treatment apparatus of this invention. It is a schematic diagram of the principal part for demonstrating an example of a structure of the conventional annealing processing apparatus. It is a schematic diagram for demonstrating an example of the heating mechanism of the conventional heating roll. It is an example which shows the general generation | occurrence | production state of the distortion of the film made into the object of annealing treatment on a heating roll, Comprising: (a) is a schematic diagram of the state which accumulated the film on the heating roll, (b) is a film | membrane. It is an expansion schematic diagram of the distortion generating state according to the position of the width direction. It is a cross-sectional schematic diagram for demonstrating an example of a structure of the heating roll provided in the annealing treatment apparatus of this invention by the cut surface. It is a front schematic diagram for demonstrating another example of the structure of the heating roll provided in the annealing treatment apparatus of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic front view for explaining an example of a configuration of a heating roll provided in the annealing apparatus of the present invention. FIG. 5 is a schematic cross-sectional view for explaining an example of the configuration of the heating roll provided in the annealing apparatus of the present invention by its cut surface.

  The present invention is an annealing apparatus having a heating roll 2 that anneals a running winding film in a surface contact state. The heating roll 2 is embedded in a plane in a plane perpendicular to the axis of the heating roll. A plurality of heaters 40, 41, 42, 45, 46 are provided in the vicinity of the inside of the outer surface of the cylindrical heating roll 2, and the surface temperature distribution in the region closer to the end than the center in the axial direction of the heating roll It can be controlled separately. The embedded heater 40 refers to the entire embedded heater, and the other embedded heaters 41 and below individually refer to heaters that are provided separately according to usage modes described later.

  In the present invention, the heating roll 2 has a uniform heating means for the entire heating roll provided with a pipe 24 through which a temperature-controlled fluid functioning as a heating medium is passed. Processing capacity can be increased.

  The heating roll 2 can be used in combination with a plurality of heating rolls in the present invention by the same arrangement as the conventional annealing apparatus 10 shown in FIG. The roll base layer 23 is a main part for maintaining the mechanical strength as the heating roll 2, and supports a pipe 24 through which the temperature-controlled fluid passes inside the roll from the surroundings. The material used as a normal heating roll can also be used. Further, the insulating protective layer 25 representing only a part of the covering portion in FIG. 1 transmits heat from the pipes and the heater to the surface of the heating roll, and evenly contacts and peels off the film 1 as the surface layer of the heating roll. Can provide a chemically stable and smooth surface. The material used for the insulating protective layer 25 can be a fluororesin.

  As the embedded heater 40, a normal resistance heating element can be used, and it can be formed by embedding a wire-shaped heating wire or pattern-printing and stacking a resistance heating element. Also, a plurality of heater terminal portions are provided in the surface area outside the film processing portion near the end of the heating roll 2, connected to the heater main body portion, and provided with a power supply brush so as to be in contact with each terminal portion. Power can be supplied from the power supply unit provided in The embedded heater can be made into one embedded heater by increasing the number of turns, and can be selected according to the required heating power and heater width.

  Furthermore, the present invention can be provided with a pipe 24 that allows the temperature-controlled fluid to pass inside as uniform heating means for the entire heating roll. As indicated by the broken line in FIG. 1 and the small circle in FIG. 5, the piping in multiple spirals facilitates heat exchange inside the heating roll and raises the annealing capability. The pipe 24 is preferably made of a material that flows a heating fluid and has high heat exchange efficiency with the roll base layer 23 and excellent workability, and ceramics or metal materials can be used. Further, the same function as described above can be obtained by processing the roll base layer 23 itself and providing a piping structure inside.

  As the temperature-controlled fluid that flows through the pipe 24 and functions as a heating medium, heated water or heated steam can be used, and these temperatures are adjusted by a heating device provided outside the annealing apparatus. It is desirable to prepare the fluid in advance. In addition to the above-described fluid, a fluid having a large heat capacity and little change due to the use of heating circulation can be used without causing danger in handling. Separate piping from the heating device to the piping inlet of the heating roll and separate piping returning from the piping outlet of the heating roll to the heating device are prepared, and these fluids can be circulated and reused during use.

Next, a method for controlling the surface temperature distribution of the heating roll by the embedded heater 40 will be described.
In FIG. 1, the embedded heaters 41 and 42 and the embedded heaters 45 and 46 are arranged in a region closer to the end than the center in the axial direction of the heating roll 2, and in particular, compared to the embedded heaters 41 and 42, the embedded heaters 45 and 46. Are arranged in a region closer to the end. Each of these heaters is supplied with power from the power supply brush through a dedicated terminal so that the temperature can be controlled independently. Further, if necessary, a temperature sensor corresponding to the surface temperature detection can be provided in the vicinity to measure the surface temperature distribution.

  By controlling each of the embedded heaters independently, the surface temperature distribution in the region closer to the end than the center in the axial direction of the heating roll 2 can be controlled separately from the other regions. Specifically, the surface temperature distribution in the region closer to the end than the center in the axial direction of the heating roll can be controlled to the high temperature side. For example, as shown in FIG. 4 described above, the both ends A and C in the width direction of the film have large undulations, and the undulation is small or almost no undulation in B which is a central region in the width direction of the film. Thus, the present invention is applied to an example in which the occurrence of distortion in the width direction of the film before the annealing treatment is not uniform. By using the annealing apparatus of the present invention, the strength of the annealing treatment to both end portions A and C in the width direction of the film can be made larger than the strength of the annealing treatment to B which is a central region in the width direction of the film. . In addition, the strength of the annealing treatment on the portion closer to the end of the film width can be increased also in the both ends A and C in the width direction of the film. By the above operation, the flatness of the film after the annealing treatment is improved to a uniform good state.

  FIG. 6 is a schematic front view for explaining another example of the configuration of the heating roll provided in the annealing apparatus of the present invention. In this example, when the width of the winding film to be annealed is different, such as the long-width film 11 and the short-width film 12, the heating roll 2 that can cope with both is shown. In the present invention, the region closer to the end than the center in the axial direction of the heating roll 2 can be captured by changing the width of the winding film 11 or 12 to be annealed, and a plurality of embedded heaters can be used to wind the annealing target. It is provided at the axial position of the heating roll corresponding to the different widths of the take-off film.

  That is, the embedded heaters 41 and 42 and the embedded heaters 45 and 46 are provided in the axial position near the end of the heating roll in order to cope with the annealing process of the long film 11. In the long-width film 11 to be annealed, when the occurrence of distortion before annealing is large near the ends in the width direction of 11A and 11C and small near the center in the width direction of 11B, it is closer to the end of the heating roll. Power is supplied independently to the embedded heaters 41 and 42 and the embedded heaters 45 and 46 provided in the axial position. Moreover, by applying a larger power to the embedded heaters 45 and 46 than to the embedded heaters 41 and 42, the surface temperature of the heating roll is controlled closer to the end in the width direction of the film 11 to increase the effect of the annealing treatment. .

  Further, in order to cope with the annealing treatment of the short film 12, the embedded heaters 43 and 44 and the embedded heaters 47 and 48 are provided in the axial position near the end within the range of the corresponding film width of the heating roll. It is done. In the short-width film 12 to be annealed, when the occurrence of distortion before annealing is large near the end in the width direction of 12A and 12C and small near the center in the width direction of 12B, the axis near the end of the heating roll The embedded heaters 43 and 44 and the embedded heaters 47 and 48 provided at the directional positions are independently powered and operated. In addition, by giving a larger power to the embedded heaters 47 and 48 than to the embedded heaters 43 and 44, the surface temperature of the heating roll is controlled closer to the end in the width direction of the film 12 to increase the effect of the annealing treatment. .

  In the present invention, the surface temperature in the roll circumferential direction of the heating roll can be made uniform, and the heating roll can be rotated at the same circumferential speed as the conveyance speed of the winding film to be annealed. As expected from the manufacturing process, the longitudinal direction of the winding film to be annealed is kept uniform during stable production. Therefore, it is not necessary to specifically match the position in the circumferential direction of the heating roll with the position in the film conveyance direction, and an annealing process that can guarantee an arbitrary contact position in the direction is preferable. Therefore, the surface temperature in the roll circumferential direction of the heating roll is preferably as uniform as possible. The circumferential shape of the embedded heater is not disturbed, and the uniformity of the surface temperature in the roll circumferential direction of the heated roll is improved by maintaining the distance from the outer surface of the heated roll to the embedded heater and the uniformity of the insulating protective layer. To do.

  In addition, by rotating the heating roll at the same peripheral speed as that of the winding film to be annealed, friction between the heating roll surface and the contact surface of the film does not occur, and scratches on the film surface caused by rubbing occur. This is also preferable from the viewpoint of preventing the annealing apparatus from being kept in a smooth operation. It is possible to easily match the above two velocities by an instruction from the control system of the annealing apparatus.

DESCRIPTION OF SYMBOLS 1 ... Film 2, 3 ... Heating roll 10 ... Annealing apparatus 11 ... Film (long width)
12 ... Film (short width)
21 ... Heating medium inlet 22 ... Heating medium outlet 23 ... Roll base layer 24 ... Pipe 25 ... Insulating protective layer 40 ... Embedded heater 41, 42 ... Embedded heater (low temperature side) For long film)
43, 44 ... Embedded heater (low temperature side, for short film)
45, 46 ... Embedded heater (high temperature side, for long film)
47, 48 ... Embedded heater (high temperature side, for short film)

Claims (5)

An annealing apparatus having a heating roll that anneals the running winding film in a surface contact state,
The heating roll has a plurality of embedded heaters provided circumferentially on a plane perpendicular to the axis of the heating roll in the vicinity of the inside of the outer surface of the cylindrical heating roll,
An annealing apparatus for a film, characterized in that the surface temperature distribution in a region closer to the end than the center in the axial direction of the heating roll can be controlled separately from other regions.   2. The film annealing apparatus according to claim 1, wherein the heating roll has uniform heating means for the entire heating roll provided with a pipe through which the temperature-controlled fluid passes.   The film annealing apparatus according to claim 1 or 2, wherein a plurality of embedded heaters are provided at positions in the axial direction of the heating roll corresponding to different widths of the winding film to be annealed.   A method for annealing a film using the annealing apparatus according to any one of claims 1 to 3, wherein a heater selected from a plurality of embedded heaters is independently controlled to be used for a heating roll. A method of annealing a film, characterized in that the surface temperature distribution in a region closer to the end than the center in the axial direction is controlled to the high temperature side.   5. The film annealing method according to claim 4, wherein the surface temperature in the roll circumferential direction of the heating roll is made uniform, and the heating roll is rotated at the same peripheral speed as the conveyance speed of the winding film to be annealed. .