JP6965194B2 - Film molding equipment - Google Patents

Description

The present invention relates to a film molding apparatus.

A film molding apparatus is known in which a molten resin extruded in a tube shape from a die discharge port is solidified to form a film. In the film forming apparatus, the cooling air volume, which is the air volume of the cooling air blown by the air ring onto the molten resin, and the film by the taker so that the film thickness and the film width of the folded film are the required thickness and width. Adjust the pick-up speed, which is the pick-up speed (pull).

JP-A-2017-177348

The present inventor has come up with a method for enhancing the convenience of a film forming apparatus.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a film molding apparatus with enhanced convenience.

In order to solve the above problems, the film molding apparatus according to an embodiment of the present invention is a die apparatus for extruding a molten resin to mold a film, and a control for estimating a resin viscosity based on data acquired during film molding. It is equipped with a device.

It should be noted that any combination of the above components and those in which the components and expressions of the present invention are mutually replaced between methods, devices, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a film molding apparatus capable of shortening the adjustment time.

It is a figure which shows the schematic structure of the film forming apparatus which concerns on embodiment. It is sectional drawing which shows the die and a cooling device of FIG. 1 and the periphery thereof. It is a top view which shows the die of FIG. It is a block diagram which shows the function and structure of the control device of FIG.

Before concretely explaining the present invention, an outline will be described. An embodiment of the present invention is a film molding apparatus that extrudes a molten resin from a die and solidifies the molten resin to form a film. The film forming apparatus is based on the data acquired during the forming of the film, specifically, for example, the data on the film, and the shear viscosity and the extensional viscosity of the resin (hereinafter, when these are collectively referred to, or when not particularly distinguished, "resin". Estimate the viscosity). When molding a film by changing to a different type of resin than before, the resin viscosity estimated this time (after changing the resin) and the resin viscosity estimated this time (after changing the resin) are estimated when the film was molded in the past with a different resin. Considering the difference from the resin viscosity of the other resin, the cooling air volume and take-up speed when the film thickness and film width were adjusted to meet the requirements when the film was molded from the other resin, this time. Estimate the cooling air volume and take-up rate for the film thickness and film width to meet the requirements when molding the film with the resin of.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted as appropriate.

FIG. 1 shows a schematic configuration of a film forming apparatus 1 according to an embodiment. The film forming apparatus 1 forms a tubular film. The film forming apparatus 1 includes a die apparatus 2, a cooling apparatus 3, a pair of stabilizers 4, a take-up machine 5, a thickness measuring sensor 6, a width measuring sensor 22, a camera 26, a control device 7, and a winding device. The taking machine 20 is provided.

The die device 2 forms a molten resin supplied from an extruder (not shown) into a tube shape. The die device 2 particularly forms the molten resin into a tube shape by extruding the molten resin from a ring-shaped slit 18 (described later in FIG. 2). The cooling device 3 is arranged above the die device 2. The cooling device 3 blows cooling air from the outside onto the molten resin extruded from the die device 2. The molten resin is cooled and a film is formed.

The pair of stabilizers 4 are arranged above the cooling device 3 and guide the formed film to the take-up machine 5. The take-up machine 5 is arranged above the stabilizer 4. The pick-up machine 5 includes a pair of pinch rolls 38. The pair of pinch rolls 38 are driven by a motor (not shown) to rotate, and fold the guided film flat while pulling it up. The winder 20 winds the folded film to form the film roll body 11.

The thickness measurement sensor 6 is arranged between the cooling device 3 and the stabilizer 4. The thickness measurement sensor 6 measures the film thickness at each position in the circumferential direction while rotating around the tubular film. The value measured by the thickness measurement sensor 6 is sent to the control device 7.

The width measurement sensor 22 is arranged between the take-up machine 5 and the take-up machine 20 and detects the film width of the folded film. The value measured by the width measurement sensor 22 is sent to the control device 7.

The camera 26 is arranged between the cooling device 3 and the stabilizer 4 and takes a film image. The camera 26 is particularly arranged to capture a film image at the frost line, where the resin hardens. The film image taken by the camera 26 is sent to the control device 7.

The control device 7 estimates the resin viscosity based on the data acquired during the molding of the film. Further, the control device 7 sends a control command according to the measured value received from the thickness measurement sensor 6 to the die device 2, and the width of the slit 18 (particularly its discharge port) so as to reduce the variation in the film thickness in the circumferential direction. To adjust.

FIG. 2 is a cross-sectional view showing the die device 2 and the cooling device 3 and their surroundings. FIG. 3 is a top view of the die device 2. In FIG. 3, the display of the cooling device 3 is omitted.

The die device 2 includes a die main body 10, an inner peripheral member 12, an outer peripheral member 14, and a plurality of (32 in this case) adjusting units 16. The inner peripheral member 12 is a substantially columnar member mounted on the upper surface of the die main body 10. The outer peripheral member 14 is an annular member and surrounds the inner peripheral member 12. A ring-shaped slit 18 extending in the vertical direction is formed between the inner peripheral member 12 and the outer peripheral member 14. The molten resin flows upward through the slit 18, the molten resin is extruded from the discharge port (that is, the upper end opening) 18a of the slit 18, cooled by the cooling device 3, and a film having a thickness corresponding to the width of the discharge port 18a. Is formed.

The plurality of adjusting units 16 are arranged so as to surround the upper end side of the outer peripheral member 14 with almost no gap in the circumferential direction. The adjusting unit 16 is particularly cantilevered and attached to the outer peripheral member 14. A cooling device 3 is fixed above the plurality of adjusting units 16. Each of the plurality of adjusting units 16 is configured to be able to apply a radial inward pressing load or a radial outward tensile load to the outer peripheral member 14. The outer peripheral member 14 is elastically deformed by applying a pressing load or a tensile load. Therefore, by adjusting the plurality of adjusting units 16, the width of the discharge port 18a can be partially adjusted in the circumferential direction, and the film thickness can be partially controlled in the circumferential direction. When the film thickness varies in the circumferential direction, for example, a tensile load is applied to the outer peripheral member 14 from the adjusting unit 16 corresponding to the thin portion (for example, located below the thin portion). The gap of the discharge port 18a below the thin portion is increased. As a result, the variation in film thickness is reduced.

As an example, as shown in FIG. 2, the adjusting unit 16 has an actuator 24 that is driven based on a control command from the control device 7, and a lever 34 that is supported with the rotation shaft 32 as a fulcrum and receives the rotational force of the actuator 24. And the actuating rod 36 supported by the outer peripheral member 14 so as to be displaceable in the axial direction and supported by the action point of the lever 34. Then, the rotational force of the lever 34 is converted into a force in the axial direction of the operating rod 36, the force in the axial direction becomes a load on the inner peripheral member 12 or the outer peripheral member 14, and the lever 34 becomes the operating rod 36 at the point of action of the lever 34. Gives power directly to.

The cooling device 3 includes an air ring 8 and an annular rectifying member 9. The air ring 8 is a ring-shaped housing having an inner peripheral portion recessed downward. A ring-shaped outlet 8a opened on the upper side is formed on the inner peripheral portion of the air ring 8. The air outlet 8a is particularly formed so as to be concentric with the ring-shaped slit 18 centered on the central axis A.

A plurality of hose ports 8b are formed on the outer peripheral portion of the air ring 8 at equal intervals in the circumferential direction. A hose (not shown) is connected to each of the plurality of hose ports 8b, and cooling air is sent into the air ring 8 from a blower (not shown) via this hose. The cooling air sent into the air ring 8 is blown out from the air outlet 8a and blown onto the molten resin.

The rectifying member 9 is arranged in the air ring 8 so as to surround the air outlet 8a. The rectifying member 9 rectifies the cooling air sent into the air ring 8. As a result, the cooling air is blown out from the outlet 8a at a uniform flow rate and wind speed in the circumferential direction.

FIG. 4 is a block diagram schematically showing the functions and configurations of the control device 7. Each block shown here can be realized by elements such as the CPU of a computer or a mechanical device in terms of hardware, and can be realized by a computer program or the like in terms of software, but here, it is realized by their cooperation. The functional block is drawn. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

The control device 7 receives an operation input by a user and a communication unit 40 that executes communication processing with the thickness measurement sensor 6, the width measurement sensor 22, and the camera 26 according to various communication protocols, and displays various screens on the display unit. Referenced and updated by the U / I unit 42 to be displayed, the data processing unit 46 that executes various data processing based on the data acquired from the communication unit 40 and the U / I unit 42, and the data processing unit 46. A storage unit 48 for storing data is included.

The storage unit 48 includes a correspondence storage unit 64 and a resin viscosity storage unit 66. The correspondence storage unit 64 stores the film thickness and the load that the adjusting unit 16 should apply to the outer peripheral member 14 in order to make the film having the film thickness a target film thickness in association with each other. The resin viscosity storage unit 66 stores the type of resin, the resin viscosity, the take-up speed when the resin viscosity is measured, and the cooling air volume in association with each other. The resin viscosity storage unit 66 may be able to distinguish whether these data are the data before the adjustment of the cooling air volume and the take-up speed is completed or the data after the adjustment is completed.

The data processing unit 46 includes an acquisition unit 50, a determination unit 52, an adjustment operation control unit 54, a resin viscosity estimation unit 56, and a display control unit 58. The acquisition unit 50 acquires the film thickness measured by the thickness measurement sensor 6, the film width measured by the width measurement sensor 22, and the film image captured by the camera 26.

The determination unit 52 determines the load to be applied to the outer peripheral member 14 by each adjustment unit 16 in order to reduce the variation in the film thickness in the circumferential direction. In particular, the determination unit 52 determines the load to be applied to the outer peripheral member 14 with reference to the film thickness at each position in the circumferential direction measured by the thickness measurement sensor 6 and the correspondence storage unit 64.

The adjustment operation control unit 54 transmits a control command to the adjustment unit 16 so as to apply the load determined by the determination unit 52 to the outer peripheral member 14.

The resin viscosity estimation unit 56 includes a shear viscosity estimation unit 60 and an extensional viscosity estimation unit 62.

The shear viscosity estimation unit 60 estimates the shear viscosity (μ). In the present embodiment, the shear viscosity estimation unit 60 estimates the shear viscosity (μ) by the following equation (1).
μ = t / γ (1)
here,
t: Shear stress γ: Shear velocity.

In the present embodiment, it is considered that the following equations (2) and (3) are satisfied for the shear stress (t) and the shear rate (γ).
t = F / S ・ ・ ・ (2)
γ = v / H ・ ・ ・ (3)
here,
F: The pulling force [N], which is the force at which the film is picked up (pulled) by the picking machine 5.
S: Cross-sectional area of the molded film [m ² ]
v: Pick-up speed (moving speed of the film in the frost line) [m / s], which is the speed at which the film is picked up (pulled) by the pick-up machine 5.
H: Film thickness [m]
Is.

The cross-sectional area (S) is represented by the following formula (4) using the circumference (2πy) of the film and the film thickness (H).
S = 2πy × H
= 2πyH ・ ・ ・ (4)
here,
y: Radius of the molded film [m]
Is.

The radius (y) of the film is represented by the following formula (5).
y = w / π ・ ・ ・ (5)
here,
w: Film width [m]
Is.
Equation (5) is derived from the fact that the circumference (2πy) of the film is equal to twice the film width (w).

Therefore, the equation (1) can be rewritten as the following equation (6).
μ = F / 2wv ・ ・ ・ (6)

The extensional viscosity estimation unit 62 estimates the extensional viscosity (η). In the present embodiment, the extensional viscosity estimation unit 62 estimates the extensional viscosity (η) by the following equation (7).
η = σ / ε (7)
here,
σ: Elongation stress ε: Elongation speed.

In the present embodiment, it is considered that the following equations (8) and (9) are satisfied for the elongation stress (σ) and the elongation rate (ε).
σ = F / S ・ ・ ・ (8)
ε = v / L ・ ・ ・ (9)
here,
L: Frost line height [m], which is the height from the discharge port 18a of the die device 2 to the frost line.
Is.

Therefore, the equation (7) is rewritten into the following equation (10).
η = FL / 2wHv ・ ・ ・ (10)

When the shear viscosity and the extensional viscosity are estimated by the shear viscosity estimation unit 60 and the extensional viscosity estimation unit 62, respectively, they are stored in the resin viscosity storage unit 66 in association with the take-up speed and the cooling air volume.

When estimating the shear viscosity (μ) and the extensional viscosity (η) by the equations (6) and (10), the values to be input to the parameters of the equations (6) and (10) can be specified as follows. The take-up force F can be specified by detecting the drive current flowing through the motor that drives the pair of pinch rolls 38 of the take-up machine 5. The film width w is measured by the width measurement sensor 22. The take-up speed v can be specified by detecting the rotation speed of the motor that drives the pair of pinch rolls 38. The frost line height can be visually specified by the user from the film image taken by the camera 26. The film thickness H is measured by the thickness measuring sensor 6. That is, the shear viscosity (μ) and the extensional viscosity (η) can be estimated from the measured values from the apparatus generally provided in the film forming apparatus 1.

The frost line height L can also be estimated from the following equation (11) if the heat transfer coefficient (HTC) is known. In this case, the camera 26 becomes unnecessary.
_{L = mCp / HTC × ln {} - (T die -T air) / (- T solid + T air)} × 1 / 2πy ··· (11)
here,
m: Mass flow rate Cp: Heat capacity [J / Kg / K]
T _die : The temperature of the molten resin extruded from the die device 2 T _air : The temperature of the cooling air blown by the cooling device 3 _{onto the molten resin T solid} : The temperature at which the resin solidifies.

The display control unit 58 causes a predetermined display unit to display the resin viscosity estimated by the resin viscosity estimation unit 56. At this time, the display control unit 58 refers to the resin viscosity storage unit 66, and refers to the resin viscosity of the other resin estimated when the film was molded in the past with a resin different from this time, and the other resin. The cooling air volume and take-up rate when the film thickness and film width are adjusted to meet the requirements when the film is formed by the above are displayed together with the resin viscosity estimated this time. Although not particularly limited, the display control unit 58 may display the average values of the resin viscosity, the take-up speed, and the cooling air volume estimated after the adjustment is completed as the resin viscosity, the take-up speed, and the cooling air volume in the past molding. good.

The operation of the film forming apparatus 1 configured as described above will be described.
When molding a film by changing to a different type of resin than before, the user first has the take-up speed, the extrusion amount, which is the amount of resin extruded from the die device 2 per unit time, and the extruded amount. The amount of air blown out per unit time from an air outlet (not shown) formed on the inner peripheral member 12 for expanding the molten resin and the amount of cooling air are determined.

Once the film formation is initiated, the user adjusts the take-up rate, extrusion rate, blowout rate and cooling air volume so that the film thickness and film width meet the requirements. At this time, when adjusting the take-up speed and the cooling air volume, the user determines the resin viscosity estimated by the control device 7 at a predetermined cycle, and the resin viscosity, the take-up speed, and the cooling air volume estimated in the past molding. Adjust with reference. Specifically, the user considers the difference between the resin viscosity estimated this time and the resin viscosity of the other resin estimated when the film was molded in the past with a resin different from this time. From the cooling air volume and take-up speed when the film thickness and film width are adjusted to meet the requirements when the film is molded with the resin of this time, the film thickness and film width meet the requirements when molding the film with the resin this time. Estimate the cooling air volume and take-up speed for this.

As an example, the user may calculate the ratio of the extensional viscosity to the shear viscosity for each of the resin viscosity estimated this time and the resin viscosity estimated in the past molding. The larger this ratio is, the more difficult it is for the film to stretch. Therefore, the larger the ratio for the resin used in this molding is for the resin used in the past molding, the higher the cooling air volume and / or the take-up speed. However, the smaller the amount, the lower the cooling air volume and / or the take-up speed may be. If there are multiple types of resin viscosities such as resin viscosities in past molding, the current cooling air volume and take-up rate can be estimated from the cooling air volume and take-up rate of the resin with the closest resin viscosity. You may.

Even after the above adjustment is completed, the control device 7 continues to estimate the resin viscosity at a predetermined cycle, and stores the estimated resin viscosity in the resin viscosity storage unit 66 in association with the take-up speed and the cooling air volume. This time, the data stored in the resin viscosity storage unit 66 is used for adjustment such as when changing to another resin.

Further, in parallel with the above-mentioned adjustment or after the above-mentioned adjustment is completed, the control device 7 sends a control command according to the value measured by the thickness measurement sensor 6 to the die device 2, and the variation in the film thickness in the circumferential direction is small. The width of the slit 18 is adjusted so as to be.

Subsequently, the effect of the present embodiment will be described. According to the film molding apparatus 1 according to the present embodiment, the resin viscosity is estimated based on the data acquired during molding. Therefore, for example, when the film is molded by exchanging with a different type of resin than before, the resin viscosity estimated this time and the difference estimated when the film was molded in the past with a resin different from this time. Considering the difference from the resin viscosity of the resin in the above, when the film is molded from the other resin, the film thickness and the film width are adjusted to meet the requirements. It is possible to estimate the cooling air volume and the take-up speed for the film thickness and film width to meet the requirements when molding. This makes it possible to adjust the film forming apparatus 1 in a relatively short time.

Further, according to the film forming apparatus 1 according to the present embodiment, the resin viscosity can be basically estimated from the measured value or the like from the apparatus generally provided in the film forming apparatus 1. Generally, in order to obtain the resin viscosity, a dedicated device for that purpose is prepared for measurement, or a specialized contractor is requested to perform the measurement. According to the film forming apparatus 1 according to the present embodiment, since they are unnecessary, the cost can be suppressed.

The configuration and operation of the film forming apparatus according to the embodiment have been described above. It will be appreciated by those skilled in the art that these embodiments are exemplary and that various modifications are possible in the combination of their respective components, and that such modifications are also within the scope of the present invention.

In the embodiment, the case where the discharge port 18a of the die device 2 is a so-called round die having an annular shape has been described, but the present invention is not limited to this. At least a part of the technical idea of the embodiment can be applied to a so-called T-die having a linear discharge port.

Although not particularly mentioned in the embodiment, the control device 7 may calculate the molding stability by a predetermined formula using the resin viscosity. For example, the control device 7 may calculate the ratio of the extensional viscosity to the shear viscosity as the molding stability. The smaller the ratio, the easier it is for the control device 7 to stretch the film, and the more likely it is that the control device 7 receives the cooling air from the cooling device 3 and vibrates. Therefore, the control device 7 sets a threshold value for the cooling air volume according to the magnitude of the ratio, and sounds that the film is an unstable setting that can vibrate when the user sets the cooling air volume exceeding the threshold value. The display may warn the user.

Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from the combination have the effects of the combined embodiments and variants.

1 film forming device, 2 die device, 7 control device, 56 resin viscosity estimation unit, 60 break viscosity estimation unit, 62 extensional viscosity estimation unit.

Claims (4)

A die device that extrudes molten resin to form a film,
Equipped with a control device,
The control device is
A resin viscosity estimation unit that estimates the resin viscosity of the resin used for film molding based on the data acquired during film molding, and a resin viscosity estimation unit.
Stores resin viscosity information including the type of resin used for film molding, the resin viscosity of the resin estimated by the resin viscosity estimation unit, and the take-up speed and cooling air volume when the resin viscosity is estimated. Including a resin viscosity storage unit
The resin viscosity storage unit stores resin viscosity information when a film was molded in the past with a resin different from this time.
The control device further
The resin viscosity of the other resin estimated when the film was molded with a different resin in the past, and the film thickness and film width are adjusted to meet the requirements when the film is molded with the other resin. A display control unit that displays the take-up speed and cooling air volume at the time together with the resin viscosity estimated this time.
A film molding apparatus including an input unit that receives input of a take-up speed and a cooling air volume by a user. When the take-up force, which is the force with which the film is taken up, is F, and the cross-sectional area of the film is S, the resin viscosity estimation unit regards F / S as shear stress, and sets the take-up speed, which is the speed at which the film is taken up, as v. when the thickness of the film and H, the v / H and all the shear rate, when the shear stress t, the shear rate and gamma, and the estimating means estimates the t / gamma and shear viscosity as a tree fat viscosity The film forming apparatus according to claim 1. When the take-up force, which is the force with which the film is taken up, is F, and the cross-sectional area of the film is S, the resin viscosity estimation unit regards F / S as an extensional stress, and sets the take-up speed, which is the speed at which the film is taken up, as v. when the frost line height and L, v / L was elongation rate and all, the tensile stress sigma, when the elongation rate and epsilon, to estimate the sigma / epsilon and elongational viscosity as a tree fat viscosity The film forming apparatus according to claim 1 or 2. The resin viscosity storage unit according to any one of claims 1 to 3, wherein the resin viscosity storage unit can distinguish whether the adjustment of the take-up speed and the cooling air volume is before or after the completion. Film molding equipment.

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