JP2007303979A - Device for measuring film characteristics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring film characteristics, capable of measuring accurately online a characteristic value in the circumferential direction of a blown film. <P>SOLUTION: This measuring device for film characteristics for measuring the profile of a cylindrical film formed continuously is equipped with an orientation degree measuring means for measuring the orientation degree in the circumferential direction of the cylindrical film, and a generation means for orientation profile or the thickness profile of a film, based on a signal from the orientation degree measuring means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is applied to, for example, an inflation apparatus for forming a hollow blown film or a cast film forming apparatus for forming a sheet-like film, and more specifically, by controlling the orientation characteristics of the blown film or cast film. The present invention relates to an inflation apparatus and a cast film forming apparatus that form a sheet having a uniform thickness.

  FIG. 6 is a basic configuration diagram of the inflation device. In FIG. 6, the plastic raw material extruded from the extruder 1 is formed into a sheet 3 a formed into a cylindrical shape by the ring die 2. 4 is an air supply / exhaust device.

  This cylindrical sheet is folded by a pinch roll 5. The sheet 3b that has been folded and flattened into two layers is transferred in the P direction via an appropriate stationary roll 6 and wound on a winder (not shown).

  In order to uniformly control the film thickness of such a cylindrical sheet, the film thickness must be measured. The thickness measurement must be performed not only in the sheet length direction but also in the width direction, that is, in the circumferential direction of the cylinder.

  In order to measure the thickness, a sensor for measuring the thickness is installed at a predetermined position. In this format, a predetermined angle 90 ° is rotated four times (for example, 360 °) clockwise (arrow R), and then reversely reciprocated counterclockwise (arrow R ′) by the same angle to thereby rotate the predetermined angle of each zone. The sensor 8 measures the characteristic value of the sheet folded at the position.

  For this reason, the characteristic (thickness) of two sheets is measured at the position where the characteristic value of the sheet in each zone is measured by the sensor at the predetermined position S of the edge portion of the folded sheet.

  In FIG. 6, reference numeral 10 denotes an oscillation position information unit that holds rotation information of the pinch roll 5. Reference numeral 11 denotes a folding position information unit, which holds virtual zone information for folding a sheet based on rotation information.

  An arithmetic unit 12 calculates the characteristic value of the edge by calculating the half of the folded zone information and the measurement value Ei of the two sheets overlapped at the edge S of the folded sheet. Estimate the value. This estimation calculation is executed in all zones, and the characteristic value in the circumferential direction of the sheet 3a is calculated by statistical processing (for example, average value).

  In addition, the following patent documents are known as prior art of the film characteristic measuring apparatus in the inflation apparatus.

JP 2003-315025 A JP 2003-315169 A JP 2004-025767 A

However, since it can be measured only after it is folded, it must be used in combination with rotating equipment. When the turning angle is less than 360 degrees with a swivel roll or the like, one sensor cannot measure the entire circumference. A device such as using two sensors was necessary.

  Also, since the profile generation time is determined by the rotation speed of the ring die and the operation speed of the pinch roll, it is not possible to take an early action to the operation end, and if the film deposition speed is slow, the delay time As a result, control wasted time was long. Therefore, advanced control such as model predictive control was necessary to improve controllability.

In addition, it is conceivable to measure the cylindrical film part (before folding) with a thickness by holding a drive unit. However, when using γ-ray post-scattering as a radiation source, it is an RI source. Management of operation and maintenance was difficult.
Furthermore, when using a capacitance type sensor, there are difficulties such as being easily affected by humidity and additives.

  An object of the present invention is to provide a film property measuring apparatus capable of accurately measuring a circumferential characteristic value (for example, thickness) of a blown film on-line.

In order to solve such a problem, a film characteristic measuring apparatus according to claim 1 of the present invention is a film characteristic measuring apparatus for measuring a profile of a continuously formed cylindrical film. An orientation degree and orientation angle measuring means for measuring the orientation degree and orientation angle in the circumferential direction, and a profile generating means for generating an orientation profile or a thickness profile of the film based on signals from the orientation degree and orientation angle measuring means. An apparatus for measuring film characteristics, comprising:

In Claim 2, In the film characteristic measuring apparatus of Claim 1,
The orientation degree and orientation angle measuring means is applied to an inflation device that folds a film formed with a ring die with a pinch roll and winds the folded film with a winder, and is arranged between the ring die and the pinch roll. It is characterized by that.

In Claim 3, In the film characteristic measuring apparatus of Claim 1 or 2,
The orientation degree and orientation angle measuring means is configured to rotate around the outer periphery of the cylindrical film.

In Claim 4, In the film characteristic measuring apparatus in any one of Claims 1 thru | or 3,
At least one of the ring die, the extruder, the take-up speed, and the blown air amount is operated based on outputs of the orientation degree and orientation angle measuring means and profile generating means.

The film property measuring apparatus according to claim 5 of the present invention is
In a film property measuring apparatus for measuring a profile of a continuously formed sheet-like film, an orientation degree and orientation angle measuring means for measuring the orientation degree and orientation angle in the width direction of the sheet-like film, and the orientation degree and orientation A film characteristic measuring apparatus comprising profile generating means for generating a thickness profile of the film based on a signal from an angle measuring means.

In Claim 6, In the film characteristic measuring apparatus of Claim 5,
The degree of orientation and the orientation angle measuring means are applied to a cast film forming apparatus for forming a sheet-like film, and are arranged in the vicinity of the sheet-like film.

In claim 7, in the film property measuring apparatus according to claim 5 or 6,
The orientation degree and orientation angle measuring means are driven to reciprocate in the width direction of the sheet-like film.

In Claim 8, In the film characteristic measuring apparatus in any one of Claim 5 thru | or 7,
It is characterized in that at least one of an extruder, a T-die, a take-up speed, and a draw ratio is operated based on outputs of the orientation degree and orientation angle measuring means and profile generating means.

According to the first to fourth aspects of the present invention, the orientation degree measuring means for measuring the degree of orientation of the film in the circumferential direction is arranged between the ring die and the pinch roll, and the outer periphery of the cylindrical film is rotated. And configured to operate at least one of a ring die, an extruder, and a take-off speed based on the outputs of the orientation degree measuring means and the profile generating means, based on the circumferential orientation characteristic value. Film characteristics can be controlled. As a result, the characteristic value in the circumferential direction of the blown film can be accurately measured online.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 (a, b) is a principal part block diagram which shows one Example of the film characteristic measuring apparatus of this invention. In addition, the same code | symbol is attached | subjected to the same element as the conventional apparatus demonstrated in FIG. 6, and description is abbreviate | omitted.

  In FIGS. 1A and 1B, reference numeral 20 denotes an orientation meter disposed between the ring die 2 and the pinch roll 5 in the vicinity of the outer peripheral portion of the cylindrical blown film 3a, along a ring-shaped member (not shown). It rotates in the circumferential direction indicated by the arrow in FIG.

  That is, for example, the orientation meter rotates about half a circle in the direction of arrow B starting from point A, then reverses in the C direction, rotates about half a circle from point A to point D through point A, and further in the direction E. Invert and repeat the action toward point A. Such an operation is based on wiring with respect to the orientation meter. However, if the orientation meter is moved wirelessly, it may be continuously rotated in one direction.

Here, the configuration of the orientation meter will be briefly described.
FIG. 2 is a cross-sectional view of a generally known orientation meter. In FIG. 2, a light source 111 is an LED, a laser, or the like installed substantially perpendicular to the measurement target object 112, and collects light emitted from the light source 111 using the condenser lens 113 on the measurement target object 112. Shine.

  The light receiving element 114 is, for example, 8 to 12 light receiving diodes with the light source 111 as the center, and receives the reflected light from the measurement object 112 and converts it into an electrical signal. For example, the reflection angle formed with the optical axis The orientation direction is measured by selecting θ as about 55 degrees.

In the above-described configuration, light is irradiated from the light source 111 to the measurement target object 112, and the light reflected by the measurement target object 112 is reflected by using the light receiving element 114 disposed along the optical axis irradiated from the light source 111. Measure the light distribution.
FIG. 3 shows the flow of signals. A signal converted into an electric signal by the light receiving element 114 is input to the A / D converter 131 as an element signal 130, and a light distribution measurement is performed by the distribution measuring means 132. Thereafter, the orientation calculation unit 133 calculates the orientation direction and outputs a measurement value 134.

FIG. 4 shows an example of an operation end control method for controlling the relationship between the elongation and the orientation characteristics during film formation and the degree of orientation, which are the basis of the present invention.
The relationship between the elongation during film formation and the orientation characteristics is as follows.

1) When the temperature of the film film is high, the elongation increases, and when it is low, the elongation decreases.
2) When the film thickness is thin, the elongation increases, and when it is thin, the elongation decreases.
3) When the elongation is large, the orientation is dispersed (the orientation angle spreads to the left and right), and when the elongation is small, the orientation is concentrated (the orientation angle is centered ... see the chain image).
4) When the elongation angle is large, if the orientation angle profile is positive in the clockwise direction, it becomes an S-shape that rises to the right. When the elongation rate is small, if the orientation angle profile is positive in the clockwise direction, it becomes an S-shape with a downward slope.
5) When the elongation percentage is large, the orientation angle becomes large. Conversely, when the elongation percentage is small, the orientation degree becomes small.

Next, the relationship of the operation end control method when controlling the degree of orientation is as follows.
1) When it is desired to weaken (reduce) the degree of orientation: a. Die operating direction: lower temperature or open lip b. As the operation direction of the extruder: Increase the extrusion amount.
As the operating direction of the take-up speed: slow down the take-up speed.

2) To increase (or increase) the degree of orientation: a. Die operation: raise temperature or squeeze lip b. As the operation of the extruder: Reduce the extrusion amount.
As the operation of the take-up speed: Increase the take-up speed.

That is, in general, when a film is formed, the following properties appear.
Hot → Elongation → Thin → Dispersion direction (orientation angle widens) → Strong cross-linking (strong orientation)
Cold → Elongation → Thickening → Condensation direction (Orientation angle gathers) → Weak crosslinking (Orientation is weak)
Thus, a close relationship appears between the orientation characteristics and the film thickness due to the stretching of the film raw material during film formation.
Therefore, the thickness displacement of the film can be controlled based on the orientation characteristics of the film.

  Returning to FIG. 1, reference numeral 30 denotes a weight controller that determines the weight of the raw material supplied from the extruder 1 to the ring die 2, and is omitted in the figure, but is an actuator unit, a raw material metering unit, and an extruder motor control unit. It is configured. The weight signal M from the weight controller is input to the signal processing unit 25 and used for calculation of the thickness profile signal DP.

  FIG. 5 is a functional block diagram illustrating a configuration example of the signal processing unit 25. Reference numeral 21 denotes an orientation profile generator, which receives the signal H from the orientation meter 20 and the position signal S from the measurement position information unit 22 and outputs the orientation angle and orientation degree profile HP described with reference to FIG.

  Reference numeral 23 denotes a thickness profile converter, which receives an orientation angle and orientation degree profile signal HP, and outputs a thickness profile EP in combination with the overall thickness described later. Reference numeral 24 denotes a blown film total thickness calculation unit which inputs the weight signal M and the roll speed signal RS from the weight controller 30 and calculates and outputs the total thickness H.

  As described above, according to the present invention, since it is possible to measure the cylindrical blown film without contact, the thickness profile of the blown film in the film circumferential direction can be measured online. In addition, in the configuration in which the orientation meter is fixedly disposed in the equipment having the rotating structure, the structure of the sensor driving unit or the like is not required, and an inexpensive system can be configured.

  Since the measurement can be performed quickly without taking the trouble of measuring offline, the feedback to the film thickness control can be accelerated and the product quality can be improved. In addition, since it is not necessary to unfold the film itself, the product yield can be improved.

  The foregoing descriptions are merely specific preferred embodiments for the purpose of describing and illustrating the present invention. In the embodiments, the example in which the film property measuring apparatus of the present invention is applied to an inflation apparatus has been described. However, the present invention may be applied to, for example, a cast film forming apparatus, and is not limited to this application example.

In addition, the orientation meter may have another configuration.
Therefore, the present invention is not limited to the above-described embodiments, and includes many changes and modifications without departing from the essence thereof.

It is a principal part block diagram which shows one Example of the film characteristic measuring apparatus which concerns on this invention. It is principal part sectional drawing which shows the general structural example of an orientation meter. It is a signal flow of the orientation meter in FIG. It is a figure which shows an example of the investigation end control method when controlling the relationship between the elongation at the time of film film-forming, an orientation characteristic, an orientation degree, and an orientation angle. 3 is a functional block diagram illustrating a configuration example of a signal processing unit 25. FIG. It is a principal part block diagram which shows an example of the conventional orientation meter.

Explanation of symbols

1 Extruder 2 Ring die 3a Sheet (cylindrical)
3b sheet (double stack)
DESCRIPTION OF SYMBOLS 4 Supply / exhaust apparatus 5 Pinch roll 6 Stationary roll 8 Sensor 10 Oscillation position information part 11 Folding position information part 12 Calculation part 20 Orientation meter 21 Orientation profile production | generation means 22 Measurement position information detection means 23 Thickness profile conversion means 24 Thickness calculation Part 30 Weight control part

Claims (8)

In a film property measuring apparatus for measuring a profile of a cylindrical film that is continuously formed, an orientation degree and orientation angle measuring means for measuring the orientation degree and orientation angle in the circumferential direction of the cylindrical film, and the orientation degree and A film characteristic measuring apparatus comprising profile generating means for generating an orientation profile or thickness profile of the film based on a signal from an orientation angle measuring means.   The orientation degree and orientation angle measuring means is applied to an inflation device that folds a film formed with a ring die with a pinch roll and winds the folded film with a winder, and is arranged between the ring die and the pinch roll. The film characteristic measuring apparatus according to claim 1, wherein   3. The film characteristic measuring apparatus according to claim 1, wherein the orientation degree and orientation angle measuring means are configured to rotate on the outer periphery of the cylindrical film.   4. The apparatus according to claim 1, wherein at least one of the ring die, the extruder, the take-up speed, and the blown air amount is operated based on outputs of the orientation degree and orientation angle measuring means and profile generating means. The film characteristic measuring device according to 1.   In a film property measuring apparatus for measuring a profile of a continuously formed sheet-like film, an orientation degree and orientation angle measuring means for measuring the orientation degree and orientation angle in the width direction of the sheet-like film, and the orientation degree and orientation A film characteristic measuring apparatus comprising profile generating means for generating a thickness profile of the film based on a signal from an angle measuring means.   6. The film characteristic according to claim 5, wherein the degree of orientation and the orientation angle measuring means are applied to a cast film forming apparatus for forming a sheet-like film, and are arranged in the vicinity of the sheet-like film. measuring device.   7. The film property measuring apparatus according to claim 5, wherein the orientation degree and orientation angle measuring means are driven to reciprocate in the width direction of the sheet-like film. The operation according to any one of claims 5 to 7, wherein at least one of an extruder T die, a take-off speed, and a draw ratio is operated based on outputs of the orientation degree and orientation angle measuring means and profile generating means. Film characteristic measuring device.

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