JPH11207804A - Apparatus and method for controlling thickness of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To finish the winding form (outer shape) of a roll obtained by taking up a molded film to the optimum state free from unevenness. SOLUTION: In the molding of a film wherein post-treatment such as drying or heat treatment is applied to a raw material soln. extruded from a lip heater type die continuously to obtain a film which is, in turn, taken up in a roll form, a film thickness control apparatus 10 is constituted of a thickness meter 30 measuring the thickness of the film in the lateral direction thereof, a temp. controller 40 individually adjusting the temps. of a plurality of the heaters embedded in the vicinal part of the die lip of a die 22, an outer shape operator 42 calculating the completed outer shape of the film taken up in a roll form from the measured value of the thickness meter 30 and a correction judge device 44 operating the temp. controller 40 on the basis of the calculation result of the outer shape operator 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for controlling the thickness of a film obtained by subjecting a raw material solution continuously extruded from a lip heater type die to post-processing such as drying and heat treatment. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film thickness control device and a control method for finishing a roll (finished outer shape) of a roll obtained by winding a film into an optimum state.

[0002]

2. Description of the Related Art The thickness of a film obtained by subjecting a raw material solution continuously extruded from a lip heater type die to post-treatments such as drying and heat treatment is monitored to see if the film has a desired thickness. Conventionally, when there is a portion having a deviation exceeding a predetermined range from the thickness to be formed, a film is formed using a thickness control device (control method) for automatically correcting the thickness of the portion. These film moldings are shown in FIG.
As shown in FIG. 5, the raw material solution 36 continuously extruded from the die 22 is subjected to post-processing such as drying and heat treatment by a continuous processing device (not shown), and then the obtained film 26 is formed.
In a normal process of forming a roll-shaped roll 32 by a winder (not shown), a thickness gauge 30 for measuring the thickness in the width direction of the film 26 is installed, and the temperature is corrected based on the measured value of the thickness gauge 30. The film thickness correction is performed by the device 4.

In other words, heaters 28 are buried at equal intervals in the width direction of a raw material solution 36 to be extruded in the vicinity of a die lip portion of the die 22, as shown in FIGS.
If any of the thickness values measured by the thickness gauge 30 deviate from the target thickness beyond an allowable range, the temperature of the heater 28 corresponding to the location is adjusted by the temperature correction device 4. Then, by changing the viscosity of the raw material solution 36 extruded through the vicinity of the adjusted heater 28,
The film thickness at the location is corrected.

[0004]

However, in the thickness control device 2, only the thickness of one film is to be controlled, and the management of the winding shape (the completed outer shape of a roll obtained by winding the film) is controlled. Is not done at all. That is, even if the thickness of one film falls within the allowable range, the deviation is accumulated as the film is wound up and the films are stacked in a roll shape, and as shown in FIG. This causes a problem that the appearance is impaired due to the formation of noticeable irregularities.

The inventor of the present invention has conducted intensive studies to solve such problems, and as a result, has arrived at the present invention.

[0006]

The gist of the film thickness control device of the present invention is that a raw material solution continuously extruded from a lip heater type die is subjected to post-treatment such as drying and heat treatment. The thickness of the film is measured in the width direction, and the temperature of a plurality of heaters embedded near the die lip of the die is individually adjusted. A temperature controller to calculate the completed outer shape of the film wound into the roll from the measured values of the thickness gauge, and operate the temperature controller based on the calculation result of the outer shape calculator. And a correction determiner.

The gist of the film thickness control method of the present invention is that a raw material solution continuously extruded from a lip heater type die is subjected to post-treatments such as drying and heat treatment, and then obtained. Used in film forming to wind the film into a roll, measure the thickness of the film in the width direction, calculate the completed outer shape of the film wound into the roll from the measured value, based on the calculation result An object of the present invention is to individually correct the temperatures of a plurality of heaters embedded near a die lip of the die.

For example, as shown in FIG. 9, if the radius of the core 34 of the roll 32 is r and the thickness of the film 26 is d,
The radius H (1) of the scroll 32 at the time of winding the first layer is H (
1) = r + d, the radius H (2) of the scroll 32 when the second layer is wound is H (2) = r + 2d, and the radius H (3) of the scroll 32 when the third layer is wound is H ( 3) = r + 3d, and the radius H (n) of the scroll 32 at the time of winding the n-th layer can be expressed as H (n) = r + nd (Equation 1).

The film length L of the first layer of the scroll 32 is
(1) is L (1) = 2π (r + d / 2), the film length L (2) of the second layer is L (2) = 2π (r + 3d / 2),
The film length L (3) of the third layer is L (3) = 2π (r +
5d / 2), and the film length L (n) of the nth layer is L (n) = 2π {r + (n-1 / 2) d} (Equation 2) Can be represented. Therefore, the total length L (SUM) of the film from the first layer to the n-th layer is represented by L (SUM) = nπ {(2r + d) + (n-1) d} (Equation 3) Can be.

The average winding speed of the film 26 is V
Then, the winding time T (1) of the first layer of the scroll 32
Is T (1) = 2π (r + d / 2) / V, and the winding time T (2) of the second layer is T (2) = 2π (r + 3d / 2) /
V, the time required for winding the third layer T (3) is T (3) = 2π
(r + 5d / 2) / V, and the winding time T (n) of the n-th layer is T (n) = 2π {r + (n-1 / 2) d} / V. · (Equation 4) Therefore, the total required winding time T (SUM) from the first layer to the n-th layer is T (SUM) = nπ {(2r + d) + (n-1) d} / V (Equation 5) Can be expressed as

As described above, by measuring the film thickness d, the winding form (outer shape) of the roll 32 after winding the film 26 for a required number of times (required time, required length) from that point is calculated. can do. Therefore, it is possible to correct the thickness of the film 26 while anticipating the shape of the completed winding 32, and it is possible to produce the winding 32 (outer shape) having a uniform appearance with no noticeable unevenness.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a film thickness control device and a control method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is used for film forming in which a raw material solution continuously extruded from a lip heater type die is subjected to post-treatments such as drying and heat treatment, and then the obtained film is wound into a roll. A thickness gauge 30 for measuring the thickness of the film 26 in the width direction, and a temperature for individually adjusting the temperatures of a plurality of heaters 28 embedded near the die lip of the die 22. A controller 40, an outer shape calculator 42 for calculating a completed outer shape of the film 26 (the roll 32) wound into a roll from the measurement values of the thickness gauge 30, and a temperature controller based on the calculation result of the outer shape calculator 42. And a correction judging device 44 for activating the control signal 40.

The thickness gauge 30 measures the thickness of the film 26 in the width direction at required width intervals.
Any thickness measuring device such as one utilizing X-rays or ultraviolet rays can be used. Further, the temperature controller 40 individually adjusts the temperature of the opposed heaters 28 buried in the vicinity of the die lip as shown in FIGS. 6 and 7. The flow rate is corrected so that the viscosity of the raw material solution passing near the heater decreases and the flow rate increases. When the heater temperature is lowered, the viscosity of the raw material solution passing near the heater increases and the flow rate is corrected so as to decrease. .

The outer shape calculator 42 is calculated by the above equations (1) to (5).
Based on the film thickness value measured by the thickness gauge 30, the outer shape (winding shape) of the completed scroll 32 is obtained by calculation using the method described above. Note that the outer shape (rolling shape) referred to herein means irregularities of the scroll 32 caused by a difference in the outer diameter (rolling thickness) of the scroll 32 with respect to the width direction of the scroll 32, and the scroll corresponding to each measurement position of the thickness gauge 30. The outer diameter (roll thickness) is calculated.

The correction judging unit 44 is provided with a contour computing unit 42.
Based on the calculation result, the deviation of the completed winding shape (outer shape of the scroll) corresponding to each thickness measurement point is obtained. If there is a point where this deviation exceeds the allowable range, the temperature controller 40 is turned off. By actuating it, the temperature of the heater 28 corresponding to that location is adjusted to correct the film thickness.

Next, the operation of the case where the film thickness is controlled by using such a film thickness control device and control method will be described.

First, similarly to the conventional film thickness control device, the thickness of the film 26 in the width direction is measured at a required width interval by the thickness gauge 30. Then, assuming that the current film thickness is constant to the end, the outer shape computing unit 42 performs an expected calculation of the winding form when the remaining number of windings of the film 26 from the present to the completion is wound. Then, since the winding form (outer shape) of the completed scroll 32 is known, the deviation of the scroll thickness (radius of the scroll 32) corresponding to each location where the thickness is measured is obtained by the correction determiner 44. If there is a location where the deviation exceeds the allowable range, the temperature of the heater 28 corresponding to the location is adjusted by the temperature controller 40, and the viscosity (flow rate) of the raw material solution 36 passing through the temperature adjustment location is adjusted. ) Is changed to perform the film 26 thickness correction.

As described above, by performing the thickness correction based on the deviation of the winding shape formed by winding the film instead of the deviation with respect to one film, it is possible to obtain a roll having an excellent appearance with less noticeable unevenness. . In addition, as for the method of calculating the deviation of the winding form 32, an average value of the thickness (the radius of the winding form) of the winding form 32 is calculated, and a portion separated from the average value by a value (ratio) or more is determined. It is a correction candidate.

In the apparatus and method for controlling film thickness of the present invention, a die 22 of a lip heater system is used. Then, the lip heater type die 22
Since the thickness is corrected by adjusting the viscosity of the raw material solution 36 by changing the heater temperature, the lip portion of the die 22 such as a heat bolt system, a push-pull bolt system, or a piezoelectric device system is mechanically opened and closed. It is possible to perform finer thickness adjustment as compared with other methods of performing thickness adjustment by using a conventional method. further,
Due to such a structural difference, the die 22 of the lip heater type has an adjustment interval pitch (heater 28) compared to other types.
(Interval) can be reduced, and the thickness can be adjusted at smaller intervals in the width direction of the film 26. Accordingly, the local thickness adjustment of the film 26 can be performed with high accuracy, and the thickness adjustment of the film 26 can be performed with higher accuracy than in the other methods described above.

Although the embodiment of the present invention has been described above, the film thickness control apparatus and control method according to the present invention can be implemented in other modes. For example, film thickness measurement with a thickness gauge can be performed at any width interval. However, the smaller the measurement interval of the thickness gauge, the more accurate the expected outer shape of the completed roll.

In addition to calculating the deviation of the winding form at the time of completion, based on the deviation from the average value, for example, an arbitrary value such as a median value between the maximum value and the minimum value of the measured values may be used. The deviation can be determined by the method. Further, the thickness measurement by the thickness gauge may be continuously performed in real time, or may be performed at required time intervals.

Further, in the above-described embodiment, the winding shape of the roll is controlled for the thickness, but it is of course possible to use the roll in combination with a conventional apparatus and method for controlling the thickness of one film. . In this case, the thickness control is performed for both the thickness of one film and the roll of the roll.

The film thickness control device and the control method according to the present invention can be used for any film formation. Preferably, the film thickness control device and the control method use a reaction-curable resin film, particularly preferably a polyamic acid in an organic solvent solution. It can be applied to the production of an imidized PI film.

As described above, various embodiments of the film thickness control device and control method according to the present invention have been described with reference to the drawings. However, the present invention is not limited to the illustrated film thickness control device and control method. For example, as shown in FIG. 2, a thickness gauge 30 for measuring the thickness of the film 26 in the width direction, and a temperature controller 40 for individually adjusting the temperatures of a plurality of heaters 28 embedded near the die lip of the die 22.
And a calculation / correction unit 46 that calculates the completed outer shape of the film 26 (the roll 32) wound into a roll from the measurement value of the thickness gauge 30 and operates the temperature controller 40 based on the calculation result. As shown in FIG. 3, the film thickness control device 12 is configured to measure the thickness in the width direction of the film 26, and the film 26 wound into a roll from the measured value of the thickness meter 30. A film thickness controller using a thickness corrector that calculates a completed outer shape of the (scroll 32) and individually adjusts the temperature of a plurality of heaters 28 embedded near the die lip of the die 22 based on the calculation result. 14 can be configured. In addition, the present invention can be implemented in various modified, modified, and modified embodiments based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0026]

According to the film thickness control apparatus of the present invention, the appearance of the completed scroll can be calculated by the outer shape calculator based on the measurement value of the thickness gauge. As a result, the film thickness can be controlled not only for one film but also for the finished roll.

Further, according to the film thickness control method of the present invention, it is possible to control the film thickness not only for one film but also for the finished roll. Thereby, even if the deviation of one film falls within the allowable range, it is possible to prevent the deviation from accumulating to cause a significant unevenness in the winding form, and to provide an excellent winding form in which the unevenness is not conspicuous. You can get a scroll.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a film thickness control device and a control method according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the film thickness control device and the control method according to the present invention.

FIG. 3 is a block diagram showing still another embodiment of the film thickness control device and the control method according to the present invention.

FIG. 4 is a side view showing an outline of a conventional film thickness control device and control method.

FIG. 5 is a top view of the film thickness control device and control method shown in FIG.

6 is an enlarged XX line sectional view of a main part of the film thickness control device and the control method shown in FIG. 4;

FIG. 7 is an enlarged Y-Y sectional view of a main part of the film thickness control device and control method shown in FIG.

FIG. 8 is a perspective view of a conventional scroll.

FIG. 9 is an explanatory view showing a film lamination state of the scroll shown in FIG. 8;

[Explanation of symbols]

 2: Conventional thickness control device 4: Temperature correction device 10, 12, 14: Thickness control device 20: Liquid supply device 22: Die 24: Roll 26: Film 28: Heater 30: Thickness gauge 32: Scroll 34: Roll core 36 : Raw material solution 40: temperature controller 42: outer shape calculator 44: correction determiner 46: calculation / corrector 48: thickness corrector

Claims (2)

[Claims] 1. A raw material solution continuously extruded from a lip heater type die is subjected to post-treatments such as drying and heat treatment, and then the obtained film is used for film forming to be wound into a roll. A thickness gauge for measuring the thickness in the width direction of the film, a temperature controller for individually adjusting the temperature of a plurality of heaters embedded in the vicinity of the die lip of the die, and a roll formed from the measured values of the thickness gauge. A film thickness control device comprising: an outer shape calculator for calculating a completed outer shape of a taken film; and a correction determiner for operating the temperature controller based on a calculation result of the outer shape calculator. 2. A raw material solution continuously extruded from a lip heater type die is subjected to post-treatments such as drying and heat treatment, and then the obtained film is used for film forming to be wound into a roll. Measure the thickness of the film in the width direction, calculate the completed outer shape of the film wound into a roll from the measured value, based on the calculation result, the heater of the plurality of heaters embedded near the die lip of the die A film thickness control method that individually controls the temperature.