JP2002225132A - Apparatus for molding blown film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a blown film stable in quality by controlling the position of a caking point to be stable. SOLUTION: An apparatus for molding the blown film is fitted with a mold 4 for molding a resin 2 extruded from an extruder into a tube, and a cooling ring 6 for cooling the tubular resin 2 discharged from the mold 4 by air supplied through an air supply system 11. A thermometer 12 for measuring the temperature of the tubular resin 2; and a control unit 15 which stabilizes the position of the caking point 13 of the resin 2, by adjusting the amount or temperature of air to be ejected from the cooling ring 6 on the basis of the comparison between the measured temperature of the resin 2 and the caking temperature of the resin 2; are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflation film forming facility capable of forming a blown film of stable quality.

[0002]

2. Description of the Related Art Inflation film forming equipment has conventionally been used for forming a tubular film (inflation film).

[0003] This blown film molding equipment uses a mold for molding resin extruded from an extruder into a tube, and a tube-like resin discharged from the mold by air supplied through an air supply system. A cooling ring for cooling.

According to such a configuration, the resin extruded from the extruder is formed into a tube shape using a mold.
Then, by blowing air from a cooling ring toward the tubular resin, the resin is cooled and a tubular blown film is formed.

Here, the position (solidification point or frost line) where the tubular resin discharged from the mold solidifies.
Has important implications for the quality of the blown film.

For example, when the position of the solidification point is far from the mold, the time required for the resin to solidify becomes longer, so that crystallization proceeds and the transparency of the product decreases, or the orientation of the resin changes. Adversely affect physical properties such as tensile strength.

On the other hand, when the position of the solidification point is close to the mold, the time required for the resin to be solidified is shortened, which makes it difficult to expand the blown film to a desired diameter.

Therefore, conventionally, a worker monitors the position of the solidification point visually and adjusts the air volume manually.

[0009]

However, as described above, it is inefficient for an operator to visually monitor the position of the solidification point and to perform the adjustment manually, which requires a great deal of labor. .

[0010] In addition, since the temperature of the air changes due to the temperature difference between day and night in the factory, the cooling capacity also changes.
This change in cooling capacity has caused the position of the solidification point to fluctuate and become unstable. Therefore, the worker had to perform the adjustment work frequently.

Accordingly, an object of the present invention is to provide an inflation film forming equipment capable of forming a blown film of stable quality by controlling the position of the solidification point to be stabilized by solving the above problems. Is to provide.

[0012]

According to the first aspect of the present invention, there is provided a mold for forming a resin extruded from an extruder into a tube and discharging the resin from the mold. Thermometer for measuring the temperature of the tubular resin discharged from the mold, in a blown film forming facility having a cooling ring for cooling the tubular resin by air supplied through an air supply system. And a control unit for stabilizing the position of the solidification point of the resin by comparing the temperature measured by the thermometer with the solidification temperature of the resin and adjusting the air volume or air temperature of the air injected from the cooling ring. It is characterized by having been provided.

According to the first aspect of the present invention, the temperature of the tubular resin discharged from the mold is measured by a thermometer, and the control unit measures the temperature measured by the thermometer and the resin. To adjust the air volume or temperature of the air injected from the cooling ring by comparing with the solidification temperature. Thereby, the position of the solidification point of the resin can be automatically stabilized. Therefore, it is possible to improve efficiency by eliminating manual adjustment work, and to form a blown film of stable quality.

According to the second aspect of the present invention, the control unit sends a control signal to an air flow control valve or a blower provided in the air supply system to thereby control the opening degree of the air flow control valve or the rotation speed of the blower. Is adjusted so that the air volume can be controlled.

According to the second aspect of the present invention, the control unit sends a control signal to an air flow control valve or a blower provided in an air supply system to open the air flow control valve. The air volume can be controlled by adjusting the rotation speed of the blower. Thus, the same function and effect as the first aspect can be obtained.

According to a third aspect of the present invention, the control unit can control a wind temperature by sending a control signal to a temperature control unit provided in the air supply system.

According to the third aspect of the present invention, the control unit sends a control signal to the temperature control unit provided in the air supply system,
Wind temperature can be controlled. Thus, the same function and effect as the first aspect can be obtained.

[0018]

First Embodiment A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.

First, the construction will be described. The blown film forming equipment comprises a resin 2 extruded from an extruder 1.
Is formed into a tubular inflation film 3. In this case, the resin 2 is pulled upward from the mold 4, but may be pulled downward. In addition, a pinch roll 5 for crushing and flattening the inflation film 3 and taking it out is disposed above the mold 4.

Further, a cooling ring 6 for cooling the tubular resin 2 discharged from the mold 4 by air is provided on an outer peripheral portion of the mold 4. The cooling ring 6 is connected to an air supply system 11 including an air volume control valve 7, a hose 8, a duct 9, a blower 10, and the like.

In the first embodiment, a thermometer 12 for measuring the temperature of the tubular resin 2 discharged from the mold 4 is provided. The thermometer 12 indicates the solidification point 13 of the resin 2.
It is preferable to dispose it near the side of the designated position of the (frost line). The thermometer 12 may be movable in the direction in which the position of the solidification point 13 fluctuates (in this case, it can be moved up and down). It is preferable to use a thermometer 12 such as a non-contact radiation thermometer as the thermometer 12.

A temperature control unit 14 such as a heat exchanger for controlling the temperature of air is provided in the air supply system 11.

The position of the solidification point 13 of the resin 2 is stabilized by comparing the temperature measured by the thermometer 12 with the solidification temperature of the resin 2 and adjusting the amount or temperature of the air injected from the cooling ring 6. Control unit 15
Is provided.

By sending control signals 16 and 17 to the air volume control valve 7 or the blower 10, the control unit 15 can control the air volume by adjusting the opening of the air volume control valve 7 or the rotation speed of the blower 10. .

The control unit 15 can control the wind temperature by sending a control signal 18 to the temperature control unit 14.

Next, the operation of the first embodiment will be described.

The resin 2 extruded from the extruder 1 is
And formed into a tube shape. Then, by blowing air from the cooling ring 6 toward the tubular resin 2, the resin 2 is cooled, and the tubular blown film 3 is formed. The formed blown film 3 is flattened by being crushed by the pinch roll 5 and is taken to the downstream side.

At this time, the temperature of the tubular resin 2 discharged from the mold 4 is measured by a thermometer 12. Then, the control unit 15 compares the temperature measured by the thermometer 12 with a preset solidification temperature of the resin 2 to adjust the amount or temperature of the air injected from the cooling ring 6.

Thus, regardless of the change of the surrounding environment,
The position of the solidification point 13 of the resin 2 can be automatically stabilized. Therefore, it is possible to improve efficiency by eliminating manual adjustment work, and to form the blown film 3 with stable quality.

At this time, the control unit 15 sends control signals 16 and 17 to the air flow control valve 7 or the blower 10 provided in the air supply system 11 to control the opening degree of the air flow control valve 7 or the rotation speed of the blower 10. The air volume is controlled by adjusting.

The control unit 15 sends a control signal 18 to a temperature control unit 14 provided in the air supply system 11 to control the air temperature.

More specifically, when the temperature measured by the thermometer 12 is higher than the solidification temperature of the resin 2, the solidification point 13
Is higher than the designated position, the cooling capacity is increased to lower the position of the solidification point 13 to the designated position. Conversely, if the temperature measured by the thermometer 12 is lower than the solidification temperature of the resin 2, the position of the solidification point 13 is lower than the specified position. Raise to the specified position.

In order to increase the cooling capacity, first, the air flow is increased by adjusting the opening of the air flow control valve 7 or the rotation speed of the blower 10. If the air volume is increased too much, the shapes of the resin 2 and the blown film 3 become unstable, so that when the air volume increases to a certain extent, the subsequent control is performed by lowering the air temperature with the temperature control unit 14.

In order to weaken the cooling capacity, the air temperature is first raised by the temperature control unit 14, contrary to the above.
In the subsequent control, the opening degree of the air volume control valve 7 or the rotation speed of the blower 10 is adjusted to reduce the air volume.

As described above, by giving priority to the air volume, it is possible to control the position of the solidification point 13 while preventing the shape of the blown film 3 from becoming unstable due to air.

[0037]

As described above, according to the first aspect of the present invention, the temperature of the tube-shaped resin discharged from the mold is measured by the thermometer, and the temperature measured by the control unit is different from the temperature measured by the thermometer. The air volume or temperature of the air injected from the cooling ring is adjusted by comparing with the solidification temperature of the resin. Thereby, the position of the solidification point of the resin can be automatically stabilized. Therefore, it is possible to improve efficiency by eliminating manual adjustment work, and to form a blown film of stable quality.

According to the second aspect of the present invention, the control unit sends a control signal to the air flow control valve or the blower provided in the air supply system to adjust the opening of the air flow control valve or the rotation speed of the blower. Thus, the air volume can be controlled. Thus, the same function and effect as the first aspect can be obtained.

According to the third aspect of the present invention, the control unit can send a control signal to the temperature control unit provided in the air supply system to control the air temperature. Thereby, a practically useful effect that the same effect as that of the first aspect can be obtained can be exhibited.

[Brief description of the drawings]

FIG. 1 is a device configuration diagram according to a first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extruder 2 Resin 4 Die 6 Cooling ring 7 Air flow control valve 10 Blower 11 Air supply system 12 Thermometer 13 Solidification point 14 Temperature control unit 15 Control unit 16 Control signal 17 Control signal 18 Control signal

Claims (3)

[Claims] 1. A mold for molding a resin extruded from an extruder into a tubular shape, and a cooling ring for cooling the tubular resin discharged from the mold by air supplied through an air supply system. In a blown film molding equipment comprising: a thermometer for measuring the temperature of the tubular resin discharged from the mold, and comparing the temperature measured by the thermometer with the solidification temperature of the resin, the cooling ring And a control unit for stabilizing the position of the solidification point of the resin by adjusting the amount or temperature of the air injected from the blower. 2. The control unit sends a control signal to an air flow control valve or a blower provided in the air supply system to control the air flow by adjusting the opening of the air flow control valve or the number of revolutions of the blower. 2. The blown film molding equipment according to claim 1, wherein: 3. The blown film according to claim 1, wherein the control unit sends a control signal to a temperature control unit provided in the air supply system to control the air temperature. Molding equipment.