JPH09300431A - Slit gap adjusting device of cap, control of thickness of resin film and manufacture of resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a resin film excellent in thickness accuracy over the total width of a cap. SOLUTION: In a resin film producing line, the slit gap adjusting bolt 12 provided to a cap 1 emitting a thermoplastic resin is connected to a drive motor 23. The drive motor 23 is operated by the command value from a motor control unit 31 and the command value is operated by taking the thickness irregularity data in the width direction of the film measured by a motor controlled thickness meter 33 in an operation part 30. The rotary direction and quantity of rotation of the drive motor 23 are controlled on the basis of the command value of the motor control unit 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a slit gap adjusting device of a die for controlling the thickness of a resin film, a method of controlling the thickness of the resin film and a method of manufacturing the resin film in a resin film manufacturing line.

[0002]

2. Description of the Related Art Generally, not only improving the film thickness accuracy but also improving the film quality, the winding shape of a take-up roll is improved, and as a result, the production yield is improved. It is extremely important to improve the accuracy of.
The method for adjusting the thickness unevenness of the die for adjusting the thickness unevenness of the film can be roughly classified into the following three types.

The first method is to adjust the thickness by changing the viscosity of the thermoplastic resin discharged from the die. The basic configuration of the device is generally that a heater is provided in the die near the resin,
The resin viscosity is changed by heating the die. The second method is to adjust the thickness by changing the slit gap by utilizing thermal expansion of a bolt or the like. Since the operation amount is larger than that of the viscosity change method and the adjusting device can be designed relatively compact, it can be densely arranged in the mouth width direction, and each bolt can be controlled simultaneously, which is an excellent adjusting method.

The third method is a method of mechanically adjusting the slit gap by using a motor or the like to normally or reversely rotate the slit gap adjusting bolt.

[0005]

When the first method is adopted, the structure of the device is relatively simple, but the types of thermoplastic resin whose thickness can be adjusted are limited, and changes in the physical properties of the resin are taken into consideration. Then, the temperature control range is limited, and there is a drawback that the thickness adjustable range is small. When the second method is adopted, the film edge portion generally requires a larger operation amount than the product portion, so that there is a problem that the edge portion may not have a sufficient operation amount in some cases.

When the third method is adopted, a large operation amount can be obtained, but since the motor for rotating the slit gap adjusting bolt is traversed in the width direction of the mouthpiece and the bolts to be sequentially adjusted are operated, The thickness accuracy, which takes time to adjust the thickness, is often inferior to that of the thermal expansion type, which allows simultaneous operation over the entire width of the die. As described above, the conventional film thickness unevenness adjusting device for a spinneret has advantages and disadvantages.Therefore, when actually used in production, the type of thermoplastic, the production amount, the capital investment scale, the number of production personnel, etc. Considering the above, the above method is appropriately selected, but it does not always achieve the predetermined purpose.

Therefore, in the present invention, the thickness of the film edge, which is extremely important for stabilizing the film formation of the resin film, can be controlled with high precision in a short time, and the slit gap of the die is excellent for adjusting the thickness of the film product portion. An adjusting device, a resin film thickness control method, and a resin film manufacturing method are provided. Specifically, after unmanning the film thickness adjustment work that was conventionally done manually, in the actual production, the time from the start of film formation to the commercialization is shortened, and the film tear is also reduced. As a result, a high quality film can be manufactured with a small number of production personnel while maintaining high productivity.

[0008]

According to a first aspect of the present invention, there is provided a slit gap adjusting device for a die which adjusts a slit gap of a die for discharging a thermoplastic resin from the slit to form a resin film. A plurality of slit gap adjusting bolts provided on one of the lips for adjusting the thickness of the film, and a plurality of driving means provided to rotate or reverse each slit gap adjusting bolt. A driving means controlling thickness measuring means for measuring the thickness of the resin film during the film manufacturing process, and a difference between a measurement result obtained by the driving means controlling thickness measuring means and a predetermined reference value. Is calculated, and the drive means to be rotationally operated is selected from the plurality of drive means,
It includes a calculation means for instructing an optimum operation amount and a control means for controlling the operation direction and the operation amount of the selected drive means based on the calculation result of the calculation means.

According to a second aspect of the present invention, there is provided a slit gap adjusting device for a die, wherein the drive means is provided so as to correspond to only the slit gap adjusting bolts corresponding to the film edge portions among the plurality of slit gap adjusting bolts. As the thickness measuring means for controlling the driving means, the thickness of the film product portion of 10
The measurement range used is more than double.

According to another aspect of the present invention, there is provided a slit gap adjusting device for a die, wherein a difference between a measurement result obtained by the driving means controlling thickness measuring means and a predetermined reference value is calculated, and the plurality of driving means are controlled. Select the drive means that should be rotated,
A keyboard capable of inputting an instruction value to the arithmetic means necessary for calculating the optimum operation amount, a measurement result of the drive means controlling thickness measuring means, an arithmetic result of the arithmetic means, and a control state of the control means And a CRT display capable of displaying, and an external storage device capable of storing the measurement result of the driving means controlling thickness measuring means, the calculation result of the calculating means, and the control state of the control means.

According to a fourth aspect of the invention, there is provided a slit gap adjusting device for a mouthpiece, comprising a plurality of rods each having a heater provided on the other of the lips forming the slit of the mouthpiece and capable of adjusting the slit gap by thermal expansion. A thermal expansion slit gap adjusting means, a heater control thickness measuring means for measuring the thickness of the film provided during the film manufacturing process, and the heater control thickness. Based on the measurement result obtained by the measuring means, the difference from a predetermined reference value is calculated, and the thermal expansion slit gap adjusting means for thermally expanding the rod among the plurality of thermal expansion slit gap adjusting means. And a heater included in the selected thermal expansion type slit gap adjusting means based on the calculation result of the calculating means and the calculating means for selecting the optimum thermal expansion amount. And further comprising a heater control means for controlling the heating value.

According to a fifth aspect of the present invention, there is provided a slit gap adjusting device for a die, wherein the driving means controlling thickness measuring means is arranged upstream of a stretching step in a resin film manufacturing line, and the heater controlling thickness measuring means is provided. It is arranged on the downstream side of the stretching step in the resin film production line. Claim 6
The method of controlling the thickness of the resin film is, a plurality of slit gap adjusting bolts for adjusting the thickness of the film, which are provided on one of the lips that form the slits of the die, and the slit gap adjusting bolts are rotated normally or A thermal expansion slit gap composed of a plurality of driving means provided for reversing and a plurality of rods each having a heater provided on the other of the lips forming the slit of the mouthpiece and capable of adjusting the slit gap by thermal expansion. A method for controlling the thickness of a resin film to be formed by using a device including an adjusting means, wherein the driving means and the thermal expansion slit gap adjusting means are controlled by a predetermined command value before starting the film formation. Is operated to set the slit gap to a substantially predetermined value over the width direction of the die.

According to a seventh aspect of the present invention, in the resin film thickness control method, the thickness of the film product portion is adjusted by the thermal expansion slit gap adjusting means, and the film edge portion is adjusted by the driving means of the resin film out of the entire width of the resin film. In this method, the thickness is adjusted by rotating the bolt for adjustment, and the operation of the thermal expansion type slit gap adjusting means and the operation of the driving means for rotating the slit gap adjusting bolt are selectively performed.

In the method for controlling the thickness of the resin film according to the eighth aspect, a motor is adopted as the driving means, and when the motor is operated, the operation is stopped by the motor whose current value exceeds a predetermined upper limit value. A command value for operating the motor is assigned to a motor in the vicinity of the motor, and in a motor in which the current value of the motor is equal to or lower than a predetermined lower limit value, the command value is ignored until the current value exceeds the lower limit value. This is a method of energizing the motor and operating the motor according to the predetermined command value after the current value exceeds the lower limit value.

According to a ninth aspect of the present invention, there is provided a method of controlling the thickness of a resin film, wherein the film production process is performed only under the film production conditions in which the amount of the thermoplastic resin discharged from the die is constant and the film production rate is constant. The film thickness is respectively measured by the driving means controlling thickness measuring means and the heater controlling thickness measuring means for measuring the film thickness provided in the film, and the driving means or the thermal expansion slit gap adjusting means is controlled. Is the way to do it. The method for producing a resin film according to claim 10, wherein a plurality of slit gap adjusting bolts for adjusting the thickness of the film, which are provided on one of the lips that form the slits of the die, and the respective slit gap adjusting bolts are straightened. A thermal expansion type comprising a plurality of driving means provided for turning or reversing and a plurality of rods each having a heater provided on the other of the lips forming the slit of the mouthpiece and capable of adjusting the slit gap by thermal expansion. A method of manufacturing a resin film using an apparatus including slit gap adjusting means, wherein a film product portion has a thickness adjusted by the thermal expansion type slit gap adjusting means, and a film edge portion has a slit gap by the driving means. It is a method of manufacturing a resin film in which the thickness is controlled by rotating the adjusting bolt to adjust the thickness.

[0016]

In the slit gap adjusting device of the die according to the first aspect of the present invention, in adjusting the slit gap of the die which discharges the thermoplastic resin from the slit to form the resin film, the driving means controlling thickness measuring means. By measuring the thickness of the resin film during the film manufacturing process, the calculating means calculates the difference between the measurement result obtained by the driving means controlling thickness measuring means and the predetermined reference value to adjust the slit gap. A drive means to be rotationally operated is selected from among a plurality of drive means for driving the utility bolt, an optimum operation amount is instructed, and the control means causes the operation means to calculate
The operation direction and operation amount of the selected drive means are controlled. Then, the gap between one lip and the other lip (slit gap of the die) can be adjusted by the slit gap adjusting bolt driven by the driving means.

Therefore, it is possible to increase or decrease the slit gap, reduce the thickness unevenness of the slit gap, and automate these processes. Further, even at a film edge portion that requires a large amount of movement, it is possible to perform thickness adjustment with high accuracy without insufficient amount of movement. In the slit gap adjusting device for a die according to claim 2, among the plurality of slit gap adjusting bolts, only the slit gap adjusting bolts corresponding to the film edge portions are provided with the driving means.
As the thickness measuring means for controlling the driving means, one having a measuring range of 10 times or more of the thickness of the film product portion is used, so that the thickness of the film edge portion is appropriate with a small amount of equipment investment. The film tear can be reduced without making the film edge thicker than necessary, and the film can be efficiently produced.

According to another aspect of the present invention, in the slit gap adjusting device of the die, the difference between the measurement result obtained by the driving means controlling thickness measuring means and a predetermined reference value is calculated, and the plurality of driving means are driven. A keyboard capable of selecting a driving means to be rotationally operated among the means and inputting an instruction value to the arithmetic means necessary for calculating the optimum operation amount; and a measurement result of the driving means controlling thickness measuring means. A CRT display capable of displaying a calculation result of the calculation means and a control state of the control means, a measurement result of the driving means controlling thickness measuring means, a calculation result of the calculation means and a control state of the control means are stored. Since it further includes an external storage device capable of controlling, the control constants of the calculation means can be arbitrarily and simply set and changed, and an accurate situation determination can be performed. Can accumulate production know-how by saving over data, it can be produced efficiently and thus high precision resin film.

According to another aspect of the invention, there is provided a slit gap adjusting device for a die, wherein a plurality of heaters are provided on the other of the lips forming the slits of the die, respectively, and the slit gap can be adjusted by thermal expansion. Thermal expansion slit gap adjusting means consisting of a rod, heater control thickness measuring means for measuring the thickness of the film provided during the film manufacturing process, and measurement results obtained by the heater controlling thickness measuring means Based on the above, a difference from a predetermined reference value is calculated, and a thermal expansion slit gap adjusting means for thermally expanding the rod is selected from among the plurality of thermal expansion slit gap adjusting means, and an optimum thermal expansion amount is calculated. A heater for controlling the heat generation amount of the heater included in the selected thermal expansion type slit gap adjusting means based on the operation unit for instructing and the operation result of the operation means. Since it further includes a control means, it can be arranged at a small pitch in the width direction of the die by adopting a thermal expansion type slit gap adjusting means that can be made compact, and at the same time, it can be operated simultaneously over the entire width of the die. Therefore, it is possible to easily achieve the adjustment of minute thickness unevenness in the width direction of the die, and it is possible to obtain a desired resin film having excellent thickness accuracy.

In the slit gap adjusting device of the die according to the present invention, the driving means controlling thickness measuring means is arranged upstream of the stretching step in the resin film manufacturing line to measure the heater controlling thickness. Since the means is arranged on the downstream side of the stretching step in the resin film production line,
It is possible to prevent film breakage in the stretching device and reduce thickness unevenness of the final product.

According to the resin film thickness control method of the present invention, a plurality of slit gap adjusting bolts for adjusting the film thickness, which are provided on one of the lips forming the slit of the die, and the slits are provided. A plurality of driving means provided for rotating the gap adjusting bolt in the normal direction or the reverse direction, and a plurality of heaters provided on the other of the lips forming the slits of the mouthpiece, each of which is provided with a heater for adjusting the slit gap by thermal expansion A method of controlling the thickness of a resin film to be formed by using a device including a thermal expansion type slit gap adjusting means made of a rod, wherein the driving means and the driving means are set at a predetermined command value before the start of film formation. By operating the thermal expansion type slit gap adjusting means and setting the slit gap to a substantially predetermined value in the die width direction, the resin film is formed immediately after the start of film formation. Only the accuracy can be schematically uniform, it is possible to improve productivity by greatly reducing the time to market.

According to the resin film thickness control method of the seventh aspect, of the entire width of the resin film, the thickness of the film product portion is adjusted by the thermal expansion slit gap adjusting means, and the film edge portion is slit by the driving means. Since the thickness is adjusted by rotating the gap adjusting bolt, the operation of the thermal expansion type slit gap adjusting means and the operation of the driving means for rotating the slit gap adjusting bolt are selectively performed. It is possible to eliminate the inconvenience that the adjustment by the adjusting means interferes with each other in each part of the film, and it is possible to improve the thickness accuracy of the resin film finally obtained.

According to the resin film thickness control method of the present invention, a motor is adopted as the driving means, and when the motor is operated, the operation is stopped by the motor whose current value exceeds a predetermined upper limit value. , Assigning a command value for operating the motor to a motor in the vicinity of the motor and ignoring the command value until the current value exceeds the lower limit value in a motor in which the current value of the motor becomes equal to or lower than a predetermined lower limit value. Then, the motor is energized, and the motor is operated according to the predetermined command value after the current value exceeds the lower limit value, so that the slit gap of the mouthpiece can be efficiently and accurately performed without performing unnecessary operation. It is possible to adjust, moreover, the interference between the slit gap adjusting bolts can be weakened to protect the bolts, and further a predetermined film edge profile can be obtained. It is possible to perform long-term production and continue to.

According to the method of controlling the thickness of the resin film of claim 9, the film production is performed only under the film production conditions in which the discharge amount of the thermoplastic resin discharged from the die is constant and the film production rate is constant. The driving means for measuring the thickness of the film provided during the process and the heater controlling thickness measuring means respectively measure the film thickness, and the driving means or the thermal expansion slit gap adjusting means. Therefore, the thickness of the resin film can be accurately measured over the entire width, and the thickness of the resin film can be controlled with high accuracy.

According to the method of manufacturing a resin film of claim 10, a plurality of slit gap adjusting bolts for adjusting the thickness of the film, which are provided on one of the lips forming the slits of the die, and the slit gaps. A plurality of rods each having a plurality of driving means provided for rotating the adjusting bolt in the normal direction or the reverse direction and a heater provided on the other of the lips forming the slit of the mouthpiece and capable of adjusting the slit gap by thermal expansion. A method for producing a resin film, using a device including a thermal expansion slit gap adjusting means consisting of: a film product portion, the thickness of which is adjusted by the thermal expansion slit gap adjusting means; Since the thickness is adjusted by rotating the slit gap adjusting bolt with the driving means, the resin film with controlled thickness is manufactured. Immediately after start of film can be a resin film thickness precision in the schematic uniform, it is possible to improve productivity by greatly reducing the time to market.

[0026]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a sectional view of a die to which the slit gap adjusting device of the present invention is applied. In FIG. 1, a thermoplastic resin supplied from an extruder (not shown) is caused to flow into a manifold 10 provided in the die 1,
After widening in the mouth width direction with the manifold 10, the lip 14
The liquid is discharged from the slit 11 composed of a and 14b.
A large number of slit gap adjusting bolts 12 are provided in the vicinity of the slits 11 in the die width direction. Generally, the slit gap adjusting bolts 12 corresponding to the thickness unevenness positions are normally rotated or By reversing, the slit gap is increased or decreased to adjust the thickness unevenness.

FIG. 2 shows a slit gap adjusting device for a die according to an embodiment of the present invention. The slit gap adjusting bolt 12 is connected to the chuck portion 20, and
0 is a drive motor 23 via a drive shaft 21 and a speed reducer 22.
Is connected to The drive motor 23 is capable of normal rotation or reverse rotation and is equipped with a position detector 24. The drive motor 23 is operated by a command value from the motor control device 31, and the command value is calculated by the motor control thickness meter 3
The thickness unevenness data in the film width direction measured in 3 is fetched through the interface 41 by the arithmetic unit 30. The operation amount of the drive motor 23, which is normally rotated or inverted according to a command value from the motor control device 31, is fed back from the position detector 24 to the calculation unit 30 via the motor control device 31. The calculation unit 30 is connected to the internal storage device 37, and necessary data is stored as appropriate.

In this case, the slit gap adjusting bolt 12
Since the drive motor 23 and the drive motor 23 are connected in a one-to-one manner, the drive motor 23 can simultaneously adjust the thickness in the mouth width direction based on the film thickness unevenness data measured by the motor control thickness gauge 33, and thus high precision is achieved. The thickness of the film edge portion can be adjusted with high precision, and the thickness of the film edge portion requiring a large amount of operation can be adjusted with high accuracy without a shortage of the amount of operation.

FIG. 3 shows another embodiment of the present invention. In order to increase the productivity of the resin film, it is naturally necessary to upsize the device. In this case, the mouthpiece width is also widened,
The number of slit gap adjusting bolts 12 is several tens, and a large number of drive motors 23 are required in the above-described embodiment.
In such an apparatus, the equipment cost rises and the apparatus itself becomes complicated, so that the work time for maintenance and the like becomes long and the productivity is lowered. Therefore, if the drive motor 23 is provided only on the slit gap adjusting bolts 12 at both ends of the die corresponding to the film edge portion and is controlled exclusively for the film edge portion, the characteristic of the motor drive system that allows a large operation amount is utilized. It becomes an effective device.

A specific description will be given with reference to FIG. FIG. 3 shows one end of the base. The base 1 is provided with a large number of slit gap adjusting bolts 12, of which bolts 12a to 12g are shown. Here, 12a-
It is assumed that 12e corresponds to the film edge portion.
Chuck portions 20a to 20e are connected to the slit gap adjusting bolts 12a to 12e, respectively.
Drive motors 23a to 23e are connected via 1a to 21e and speed reducers 22a to 22e. Drive motor 2
3a to 23e are controlled by the command values of the motor control devices 31a to 31e, and the calculation of the command values takes in the thickness data in the film width direction measured by the motor control thickness gauge 33 through the interface 41. The calculation unit 30 performs this. The thickness of the film edge is 10 compared to the product
Although the thickness is about double, the motor control thickness gauge 33 can measure the thickness of the film edge accurately because it has a measuring range that is 10 times or more that of the product portion.

In this embodiment, since the thickness of the film edge portion can be appropriately controlled with a small amount of capital investment, the film tear can be reduced without making the film edge thicker than necessary, and the production can be performed efficiently. Become. FIG.
Shows another embodiment of the present invention. A CRT display 38 and an external storage device 39 in the arithmetic unit 30.
And the keyboard 40 are connected to each other, the control constants and the like of the arithmetic unit 30 can be arbitrarily set and changed.
By displaying the calculation result on the T display, the situation can be accurately determined. Further, by connecting the external storage device 39, detailed data thereof can be stored, and by accumulating production know-how, a highly accurate film can be efficiently produced.

Yet another embodiment of the present invention is shown in FIG. A thermal expansion type slit gap adjusting device comprising a plurality of rods each having a slit gap adjusting bolt 12 on one lip of the slit of the base 1 and a heater on the other lip, and adjusting the slit gap by utilizing thermal expansion. 13 is provided. As described above, the slit gap adjusting bolt 12 includes the chuck portion 20, the drive shaft 21, and the speed reducer 2.
The drive motor 23 is connected via 2 and is driven by the command value output from the motor control device 31 based on the calculation result of the calculation unit 30. Further, the thermal expansion slit gap device 13 is connected to a heater control device 32 that controls a heater provided on the rod, and the calculation unit 30.
The amount of thermal expansion of the rod is controlled on the basis of the calculation result of, and the slit gap can be appropriately adjusted over the entire width of the die.
The computing unit 30 includes interfaces 41 and 42, respectively.
The motor control thickness gauge 33 and the heater control thickness gauge 34 are connected via the motor control thickness gauge 33, and the measurement result of the motor control thickness gauge 33 is arithmetically processed by the arithmetic unit 30 and then the motor control unit 31. To the heater control thickness gauge 34.
The measurement result of 1 is also processed by the calculation unit 30 and then transmitted to the heater control device 32.

By disposing the slit gap adjusting bolt 12 and the thermal expansion slit gap device 13 which are driven by the driving motor 23 on both sides of the slit of the die 1 over the entire width of the die, a film having excellent thickness accuracy can be obtained. However,
The device becomes complicated and expensive. Therefore, the chuck part 2
0, the drive shaft 21, the speed reducer 22 and the drive motor 23 are provided only on the slit gap adjusting bolts 12 at both ends of the die corresponding to the film edge portion and are used for controlling the thickness of the film edge portion, the operation amount is large. , It is possible to obtain a predetermined film edge profile. On the other hand, the thermal expansion type slit gap device 1 is used for controlling the thickness unevenness of the film product portion.
If the thermal expansion type slit gap device 13 is used, a compact device design can be generally made. Therefore, the thermal expansion slit gap device 13 can be arranged at a small pitch in the width direction of the mouthpiece, and further, simultaneous operation can be performed over the entire width of the mouthpiece. It is also possible to adjust minute thickness unevenness in the direction, and it is possible to obtain a desired film having excellent thickness accuracy.

Yet another embodiment of the present invention is shown in FIG. FIG. 6 shows a schematic layout of the resin film production line after being discharged from the thermoplastic resin die 1 and wound by the winding device 4 via the longitudinal stretching device 2 and the transverse stretching device 3. In FIG. 6, a longitudinal stretching device 2 and a lateral stretching device 3
In order to prevent the film from being torn, it is extremely important to control the thickness of the film edge before entering the longitudinal stretching device 2. The thickness unevenness of the film edge portion in FIG. 6 is adjusted by using a driving motor 23 (not shown), and the motor controlling thickness gauges 33a and 33b are arranged in front of the longitudinal stretching device 2. Is important.By controlling the thickness of the edge profile before film stretching, it is possible to prevent film tearing without increasing the film thickness more than necessary, so it is not only in terms of product quality but also in terms of process stabilization. It will be preferable. On the other hand, it is preferable that the heater controlling thickness gauge 34 for measuring the thickness unevenness of the film product portion is arranged before the winding device 4 which is before the final product, that is, after the transverse stretching device 3.

Further, since the production of the resin film is usually repeated and produced on each production line,
The rotation amount of the motor of the drive motor 23 and the output value of the heater of the thermal expansion type slit gap device 13 which make the thickness accuracy of the product good in each type are approximately known. Therefore, as a method for controlling the thickness of the resin film, the rotation amount of the known motor and the heater output value known in the previous period that make the thickness accuracy good before starting the film formation are respectively the drive motor 23 and the thermal expansion slit gap device. If given as an initial value to 13, the film thickness accuracy becomes almost uniform immediately after the start of film formation,
The time to commercialization can be greatly shortened and productivity can be improved.

Further, for example, when the thickness of the film edge portion is manipulated, the flow rate of the thermoplastic resin corresponding to the changed film thickness flows into and out of the film product portion side, so that the thickness of the film product portion changes. . On the contrary, when the thickness of the film product portion is manipulated, the thickness of the film edge portion changes. That is, if the thicknesses of the film edge portion and the film product portion are adjusted at the same time, they will interfere with each other, and as a result, it will be very difficult to adjust the thickness. Therefore, the operation of the thermal expansion type slit gap adjusting device provided for adjusting the thickness of the film product portion and the operation of the drive motor for rotating the slit gap adjusting bolt provided for adjusting the thickness of the film edge portion are If it is limited to only one of them, good controllability can be obtained without interfering with each other, and as a result, the accuracy of the thickness of the arriving film is also high.

Further, since the slit gap is adjusted by rotating the slit gap adjusting bolt 12, the slit gap adjusting bolt 12 has a mechanical play in the screw portion. Therefore, when the drive motor 23 is operated, if the slit gap adjusting bolt 12 is in a mechanical backlash state, the current value of the drive motor 23 becomes a smaller value than when the slit gap is actually changed. Therefore,
Bolt for adjusting slit gap 12 in mechanical looseness
Current value of the motor required to rotate the motor is measured, and a current value slightly larger than the measured value is set as the lower limit value. If the current value of the drive motor 23 is equal to or lower than the lower limit value, the current value is the lower limit value. If the drive motor 23 is energized while ignoring the rotation amount of the motor until it exceeds, and the drive motor 23 is energized to reach a predetermined rotation amount after the current value exceeds the lower limit value, mechanical play Since the slit gap does not change in the portion, the slit gap of the die can be adjusted efficiently and accurately without performing unnecessary operations. Further, when the slit gap adjusting bolts 12 are arranged at a small pitch in the die width direction, finer thickness unevenness can be adjusted, but the smaller the pitch, the more easily the bolts interfere with each other, and in some cases the interference of neighboring bolts. Therefore, an operating force exceeding the bolt strength may be required in order to give an operation amount for correcting the thickness unevenness. In this case, if the bolts are operated excessively, the bolts will be damaged, and it will take a long time to repair them, resulting in a great hindrance to production. Therefore, when the current value of the drive motor 23 is equal to or higher than a predetermined upper limit value, the operation of the slit gap adjusting bolt 12 is stopped, and the command amount to be operated by the drive motor 23 is allocated to the drive motors 23 in the vicinity. In this case, mutual interference is weakened and not only the slit gap adjusting bolt 12 can be protected but also a predetermined film edge profile can be obtained in the same manner, which enables continuous long-term production.

Further, when the thickness of the film is measured while traversing the thickness gauge provided in the film production line in the width direction of the die, the film thickness changes when the discharge amount of the thermoplastic resin discharged from the die changes. , It becomes impossible to correctly measure the thickness distribution in the width direction of the die.
Also, since the film thickness changes even if the film production speed changes, it becomes impossible to measure the thickness distribution in the die width direction as well. Therefore, the thickness gauge for motor control 33
a, 33b and the heater control thickness gauge 34, when the film thickness is measured, only under the film manufacturing conditions in which the discharge amount of the thermoplastic resin discharged from the die is constant and the film production speed is constant. It is extremely important to operate the drive motor 23 and the thermal expansion slit gap adjusting device 13 on the basis of the measurement data described above in order to correctly control the film thickness.

[0039]

According to the first aspect of the present invention, the slit gap can be increased or decreased, and the thickness unevenness of the slit gap can be reduced. Moreover, these processes can be automated, and a large operation can be performed. Even in a film edge portion that requires a large amount, it is possible to achieve a unique effect that the thickness can be adjusted with high accuracy without a shortage of the movement amount.

According to the second aspect of the present invention, the thickness of the film edge portion can be properly controlled with a small amount of capital investment, the film tear can be reduced without making the film edge thicker than necessary, and the film can be efficiently produced. It has the unique effect of being able to do it. According to the invention of claim 3, the control constants of the calculation means can be arbitrarily and simply set and changed, and moreover, it is possible to make an accurate situation judgment, and further, by storing these detailed data, the production know-how. Therefore, it is possible to efficiently accumulate a high-precision resin film and to produce a unique effect.

According to the invention of claim 4, the thermal expansion type slit gap adjusting means which can be made compact can be adopted and can be arranged at a small pitch in the width direction of the die, and moreover, the simultaneous operation can be carried out over the entire width of the die. Therefore, it is possible to easily achieve the adjustment of the minute thickness unevenness in the width direction of the die, and it is possible to obtain a desired resin film having excellent thickness accuracy.

The invention of claim 5 has a unique effect that it is possible to prevent the film from breaking in the stretching device and to reduce the thickness unevenness of the final product. The invention of claim 6 has a peculiar effect that the accuracy of the thickness of the resin film can be made substantially uniform immediately after the start of film formation, the time required for commercialization can be greatly shortened, and the productivity can be improved. .

According to the invention of claim 7, it is possible to eliminate the inconvenience that the adjustments by the gap adjusting means interfere with each other in the respective portions of the film, and consequently the accuracy of the thickness of the finally obtained resin film can be improved. It has the unique effect of being able to do it. According to the invention of claim 8, the slit gap of the die can be adjusted efficiently and accurately without performing unnecessary operation, and furthermore, the interference between the slit gap adjusting bolts is weakened to protect the bolt. Further, it is possible to obtain a predetermined film edge profile, and it is possible to achieve continuous production over a long period of time, which is a unique effect.

The invention of claim 9 has a unique effect that the thickness of the resin film can be accurately measured over the entire width, and that the thickness of the resin film can be controlled with high accuracy. The invention of claim 10 has a unique effect that the accuracy of the resin film thickness can be made substantially uniform immediately after the start of film formation, and the time required for commercialization can be greatly shortened to improve the productivity. .

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a resin film die.

FIG. 2 is a schematic configuration diagram of a slit gap adjusting device for a die according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a slit gap adjusting device for a die according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a slit gap adjusting device for a die according to still another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a slit gap adjusting device for a die according to still another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a slit gap adjusting device for a die according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Die 2 Vertical stretching device 3 Horizontal stretching device 11 Slits 12a, 12b, ..., 12g Slit gap adjusting bolt 13 Thermal expansion slit gap adjusting device 14a, 14
b lip 23a, 23b, ..., 23e drive motor 30 arithmetic unit 31 motor control device 32 heater control device 33a, 33b motor control thickness meter 34 heater control thickness meter 38 CRT display 39 external storage device 40 keyboard

Claims (10)

[Claims] 1. A device for adjusting a slit gap of a die (1) for forming a resin film by discharging a thermoplastic resin from the slit (11), the lip constituting the slit (11) of the die (1). (14
a) A plurality of slit gap adjusting bolts (12) provided on one side of (14b) for adjusting the thickness of the film.
a) (12b) ... (12g) and the slit gap adjusting bolts (12a) (12b).
.. (23a) (23b) ... (23) provided to rotate (12g) forward or reverse
e) and driving means controlling thickness measuring means (33a) (3) for measuring the thickness of the resin film during the film manufacturing process.
3b), and the thickness measuring means (33a) (33b) for controlling the driving means.
The difference between the measurement result obtained by and the predetermined reference value is calculated, and the plurality of driving means (23a) (23b)
.. (23e) selecting driving means to be rotationally operated and instructing an optimum operation amount; operation means (30); and operation of the selected drive means based on the operation result of the operation means (30). A slit gap adjusting device for a die, comprising: a control means (31) for controlling a direction and an operation amount. 2. The slit gap adjusting bolt (12) corresponding to the film edge portion among the plurality of slit gap adjusting bolts (12a) (12b) ... (12g).
a) (12b) ... (12e) only, the driving means (23a) (23b) ... (23e) are provided, and the driving means controlling thickness measuring means (33a) is provided.
The slit gap adjusting device for a die according to claim 1, wherein (33b) has a measuring range of 10 times or more the thickness of the film product portion. 3. A thickness measuring means for controlling the driving means (33)
a) The difference between the measurement result obtained by (33b) and a predetermined reference value is calculated, and the plurality of drive means (23)
a) (23b) ... (23e) A keyboard (40) capable of selecting a driving means to be rotationally operated and inputting an instruction value to the arithmetic means (30) necessary for calculating an optimum operation amount. ) And the driving means controlling thickness measuring means (33a) (33b)
CRT display (38) capable of displaying the measurement result of 1., the calculation result of the calculation means (30) and the control state of the control means (31), and the thickness measurement means (33a) (33b) for controlling the drive means.
The base according to claim 1 or 2, further comprising an external storage device (39) capable of storing the measurement result of 1., the calculation result of the calculation means (30), and the control state of the control means (31). Slit gap adjusting device. 4. A plurality of rods, each having a heater, provided on the other of the lips (14a) (14b) forming the slit (11) of the base (1) and capable of adjusting the slit gap by thermal expansion. A thermal expansion type slit gap adjusting means (13), a heater control thickness measuring means (34) for measuring the thickness of the film provided during the film manufacturing process, and the heater control thickness measuring means ( 34) calculates a difference from a predetermined reference value based on the measurement result obtained by 34), and the plurality of thermal expansion type slit gap adjusting means (13)
Among them, a thermal expansion type slit gap adjusting means (13) for thermally expanding the rod is selected, and an arithmetic unit (30) for instructing an optimum thermal expansion amount, and the selection based on the arithmetic result of the arithmetic means (30). Heater control means (3) for controlling the heat generation amount of the heater included in the thermal expansion type slit gap adjusting means (13).
2) The slit gap adjusting device for a die according to any one of claims 1 to 3, further comprising: 5. A thickness measuring means for controlling the driving means (33)
a) (33b) is arranged upstream of the stretching steps (2) and (3) in the resin film production line, and the heater controlling thickness measuring means (34) is disposed in the resin film production line. 2) The slit gap adjusting device for a die according to claim 4, which is arranged on the downstream side of (3). 6. A plurality of slit gap adjusting bolts (12a) (12b) provided on one of the lips (14a) (14b) constituting the slit (11) of the die (1) for adjusting the film thickness. ) ... (12g) and the slit gap adjusting bolts (12a) (12b).
.. (23a) (23b) ... (23) provided to rotate (12g) forward or reverse
e) and a plurality of rods which are provided on the other of the lips (14a) and (14b) constituting the slit (11) of the base (1) and each of which has a heater and which can adjust the slit gap by thermal expansion. Inflatable slit gap adjusting means (13)
A method for controlling the thickness of a resin film to be formed by using a device including, wherein the driving means (23
a) (23b) ... (23e) and the thermal expansion slit gap adjusting means (13) are operated to set the slit gap to a substantially predetermined value in the die width direction. Thickness control method. 7. The thickness of a film product portion of the entire width of the resin film is adjusted by the thermal expansion slit gap adjusting means (13), and the film edge portion is the driving means (23a).
(23b) ... (23e) rotate the slit gap adjusting bolts (12a), (12b) ... (12e) to adjust the thickness, and operate the thermal expansion slit gap adjusting means (13). And slit gap adjustment bolt (12
The method for controlling the thickness of a resin film according to claim 6, wherein the driving means (23a) (23b) ... (23e) for rotating a) (12b) ... (12e) are selectively operated. 8. The drive means (23a) (23b) ...
-(23e) is a motor (23a) (23b) ... (2
3e) and the motors (23a) (23b) ... (2
3e), when the current value of the motor exceeds the predetermined upper limit value, the operation is stopped, and the command value for operating the motor is assigned to the motor in the vicinity of the motor. For motors that are below the specified lower limit value, the command value is ignored until the current value exceeds the lower limit value, and the motor is energized.After the current value exceeds the lower limit value, the motor is operated according to the predetermined command value. The method for controlling the thickness of a resin film according to claim 6 or 7, which is operated. 9. The thickness of the film provided during the film manufacturing process is set only under the film manufacturing conditions in which the discharge amount of the thermoplastic resin discharged from the die (1) is constant and the film manufacturing rate is constant. The film thickness is measured by the driving means controlling thickness measuring means (33a) (33b) and the heater controlling thickness measuring means (34) for measuring,
The method for controlling the thickness of a resin film according to any one of claims 6 to 8, wherein the driving means (23a) (23b) ... (23e) or the thermal expansion slit gap adjusting means (13) is controlled. 10. A plurality of slit gap adjusting bolts (12a) (12b) provided on one of the lips (14a) (14b) constituting the slit (11) of the die (1) for adjusting the film thickness. ) (12e) and the slit gap adjusting bolts (12a) (12b).
.. (23e) (23a), (23b), ... (23) provided to rotate (12e) forward or reverse
e) and a plurality of rods which are provided on the other of the lips (14a) and (14b) constituting the slit (11) of the base (1) and each of which has a heater and which can adjust the slit gap by thermal expansion. Inflatable slit gap adjusting means (13)
A method for producing a resin film by using a device including, wherein the film product portion has its thickness adjusted by the thermal expansion slit gap adjusting means (13), and the film edge portion has the driving means (23a) ( 23b) ... (23e) and slit gap adjusting bolts (12a) (12b) ... (12
A method for producing a resin film, characterized in that the thickness is adjusted by rotating e) to produce a resin film having a controlled thickness.