JP2981633B2 - Tubular film manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular film manufacturing apparatus, and more particularly, to a die head having a ring nozzle and an outer blowing nozzle, and a thermoplastic machine provided with a measuring apparatus for measuring the film thickness of the tubular film. The present invention relates to an apparatus for producing a resin-made tubular film.

[0002]

2. Description of the Related Art The device mentioned above is a German patent (DE 26).
58518C2). In this apparatus, a measuring device for measuring the thickness of a processed film is disposed after a device for folding a processed tubular film flat. The air flow rate of the nozzle of the air nozzle wheel, which is located above the outer blowing ring and directs the nozzle of the outer blowing ring toward the area of the tubular film, is controlled based on the measurement result by the film thickness measuring device. It is supposed to be.

In the area of the tubular film,
The tubular film has an expansion region whose diameter gradually increases. That is, the resin exiting from the ring nozzle extends uniformly in the transverse direction and the longitudinal direction. With this device, the formation of uneven bulges in the tubular film must be avoided. The tubular film cooled by the nozzle of the air nozzle ring forms a thick region when the tubular film is finished, and the warmed region forms a thin region when the tubular film is finished.

[0004]

Blowing air on the tubular film in the expansion region, i.e., the region extending in the transverse and longitudinal directions, involves a longitudinal and transverse extension which is affected by the blowing. There is a problem that the finished thickness cannot be easily controlled. Even in the optimal case, the thickness error will be ± 20%. Furthermore, in the area of the air nozzle ring, when air is blown from the side, the processed film bubble is not pressed from the center direction toward the outer diameter, so that the inside of the film bubble must be stabilized. There is. For this purpose, in the above-mentioned prior art, a ring for blowing air from the inside of the film is provided at a high position above the air nozzle wheel, and the inside of the film bubble is stabilized by blowing the air therefrom. Furthermore, the above-mentioned prior art has a problem that the dead time determined by the time required for the tube to move from the air nozzle wheel to the thickness measuring device is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tubular film manufacturing apparatus capable of correcting the above-mentioned drawbacks of the prior art and effectively controlling the film thickness so as to further reduce the error in the finished film thickness.

Further, it is an object of the present invention to provide a long necked HDPE (shape in which it is difficult to obtain a uniform dimensional accuracy, especially a uniform thickness due to a difference in melt tension due to a temperature difference, in particular). It is an object of the present invention to provide an apparatus for manufacturing a tubular film made of HDPE or the like, which realizes uniform spreadability in processing a tubular film made of high-density polyethylene) or the like and has high uniformity in film thickness dimensional accuracy.

[0007]

According to a first aspect of the present invention, there is provided a tubular film manufacturing apparatus, comprising: an air nozzle according to a measurement result of the measuring apparatus; The flow rate of air passing through the nozzles of the group wheel is controlled, and the nozzle faces the tubular film, and the air nozzle wheel moves between the ring nozzle and the outer blowing nozzle. That is, they are arranged close to each other.

Furthermore, the measuring device, after the frost line of the tubular film, and is arranged in front of the folding device the tubular film, the tubular off
Ensures stability during molding of the film
Internal cooling for introducing air to cool the film
The air nozzle group wheel has a cooling capacity within the above range.
Same or smaller than the cooling capacity of cooling air in the area of
It is configured at last.

Further, in order to achieve the above object, the characteristic configuration of the tubular film manufacturing apparatus according to the second invention is as follows.
In the above-described apparatus for manufacturing a tubular film, the tubular film forms a long neck portion before its expansion.
In the end region of the long neck portion, an air nozzle group ring facing the outside of the tubular film and an inner stabilizer constituting an internal stabilizer located in this region are arranged. Controlling the air flow rate through the nozzles of the air nozzle group wheel according to the measurement result of the measuring device, further comprising a cooling device inside the die head, the outer diameter of the inner stabilizer is The cooling capacity of the outer blowing nozzle is at least 10 times greater than the cooling capacity of the air nozzle group in the area of the inner film, which is slightly smaller than the inner diameter of the tubular film.

[0010] The internal stabilizer introduces cooling air into the tubular film, the flow rate of which is adjusted in accordance with the measurement result of the measuring device, to form a nozzle group that can control the cooling of the inner surface of the tubular film. Preferably, it is provided in a stable body. Further, the internal stabilizer is
Advantageously, the height is adjustable.

[0011]

According to the first aspect of the present invention, since the film thickness can be adjusted effectively, the melt can be affected immediately after it exits the ring nozzle, that is, at the point where the film thickness is the thickest. According to the measurement result of the measuring device, the air flow rate passing through the nozzle of the air nozzle group wheel is controlled, and an internal stabilizer that cools the inner surface of the tubular film is provided.
Since the film is provided, a film having a small error in the finished film thickness can be reliably obtained.

Since the second invention has the above configuration,
Uniform spreadability not only results in a film of uniform thickness, but also balances the longitudinal and transverse strength of the film. Furthermore, high productivity is obtained because the air flow rate of the outer blowing nozzle is optimized. The cooling by means of the nozzles of the air nozzle group, preferably by means of point cooling, reduces the longitudinal and transverse extension of the material at the cooling point, where the film is thicker than at the uncooled point.

The cooling by the group of air nozzles takes place just before the material extends laterally. In this case, a temperature equilibrium between the strongly cooled and weakly cooled areas is essential,
The thermal effect on the film is exerted relatively precisely where it is needed. Further, the material extends along the extrusion direction and is cooled by the air nozzle group in a region having a relatively large area with respect to its thickness.

What can be achieved by the inner stabilizer is that when the tubular film is sprayed from one side by the group of air nozzles, the tubular film does not deviate from its vertical axis. in this way,
It is important that the cooling capacity of the outer blowing nozzle is greater than the cooling capacity of the air nozzle group in the end region of the neck.

[0015]

According to the first aspect of the present invention, it is possible to provide an apparatus for manufacturing a tubular film having a small error in finished film thickness.

If the measuring device is disposed after the cooling line for the tubular film and before the folding device for the tubular film, the dead time in the control system becomes extremely small , and furthermore, the time before the folding is reduced. To
Thickness of a tubular film with a circular cross section
Can be measured, so measurement accuracy can be improved
Can be. In addition, it has an internal stabilizer,
Cooling capacity is lower than that of cooling air in the area of internal stabilizer
By being configured to be the same or smaller, the air nozzle group
In the area of the ring, when air is blown from the side, the internal stability
Depending on the body, whether the processed film bubble is toward the center
Is pressed toward the outside diameter to stabilize. In addition, the tube
By cooling the inside of the film and solidifying it to some extent,
The tubular film is shifted from its vertical axis,
To the downstream side.

According to the second aspect, the H forming the long neck portion
Even in the processing of DPE or the like, it was possible to provide a tubular film manufacturing apparatus having high uniformity of spreadability.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the die head 1 includes a ring nozzle 2 from which a plastic resin comes out. Here, the tubular film 3 is formed. In the expansion region 4 of the tubular film 3, the tubular film 3 is forcibly cooled by an outer blowing nozzle 5 supplied with air through a connection port 6.

Further, between the ring nozzle 2 and the outer blowing nozzle 5, for example, an air nozzle group 7 having 32 radially inwardly directed nozzles 8 is provided.
The nozzle 8 is connected to a ring-shaped chamber 9 to which air is supplied through a connection port 10. Ring-shaped chamber 9
A control valve 11 for controlling the flow rate of air passing through each nozzle 8 is provided between the nozzle 8 and the nozzle 8.

A measuring device 12 is provided above the cooling line of the tubular film 3 and below the film folding device, and its measuring probe can be rotated forward and backward.
Changes in film thickness can be detected around the circumference of the tube. The measurement result is sent to a computer 13 that controls the control valve 11. If the measuring device 12 measures a rather thick area of the tubular film, the nozzle 8 located below this area is supplied with little or no air. On the contrary,
When measuring a very thin area of a tubular film,
The valve 11 is largely opened so that a large amount of air is supplied to a nozzle located below this region. Thus, the range of the error of the thickness of the apparatus according to the present embodiment could be reduced to almost half as compared with the case of using the conventional apparatus. This is due to a direct effect on the molten resin after exiting from the ring nozzle 2.

As is particularly apparent from FIG. 2, the nozzle opening 14 of the nozzle 8 faces obliquely upward in the direction of the tubular film. The nozzle opening 14 is a ring-shaped wall 15
The wall 15 forms a boundary with the lower side of the outer blowing nozzle 5. The opening 16 of the outer blowing nozzle 5 extends upward. The wall 17 forming the opening 16 outward has an edge above the edge of the ring-shaped wall 15. Above the outer blowing nozzle 5, there is provided a throttle 18 which is adjusted according to the diameter of the tubular film 3. Cooling air is supplied from the storage chamber 9 along the extended area of the tubular film 3.

The ports 6 and 10 are connected to separate air supply systems. In order to effectively adjust the film thickness, it is necessary that the melt is affected in the vicinity of the ring nozzle 2, that is, where the melt is relatively thick. In addition, the air flowing out of the nozzle opening 14 works sufficiently for the ring-shaped wall 15. Since the measuring device 12 is arranged after the cooling line and before the tubular film folding device, the dead time in the control system is extremely small.

[Alternative Embodiment] The present invention can be configured as follows. As shown in FIG. 3, the apparatus includes a die head 1 including a ring nozzle 2 and an outer blowing nozzle 5 surrounding the ring nozzle 2. A throttle 18 is provided above the ring nozzle 2 and the outer blowing nozzle 5. The die head 1 has an internal stabilizer 20 provided with a pipe inside thereof and having an inner stabilizer 25.
Is installed. In addition, the die head 1 has a cooling air passage (not shown).

The die head 1 is provided with an air nozzle group 7 on the outside thereof. The air nozzle group is constituted by a ring-shaped chamber 9, and a pipe-shaped air nozzle 8 is provided radially inward from the chamber 9. Is extending. Chamber 9 and air nozzle 8
And a valve 11 for controlling a flow rate flowing through each nozzle 8.
Are provided for each. The nozzle 8 is telescopically extendable and retractable in the radial direction. In this embodiment, for example, 32
Nozzles 8 are provided. Outside blowing nozzle 5
And the air nozzle group wheel 7 are connected to a separate air supply system. A rotating measuring device 12 is attached to the upper side of the air nozzle group 7 by a support member (not shown) for measuring the film thickness. This measuring device 12
Measures the film thickness using, for example, capacitance or far infrared rays. The device 12 can rotate in a reversible manner.

The material emerging from the gap in the ring nozzle 2 first creates a tapered long neck 22 in which the material extends long. Expansion is performed at the end of the long neck to form an expansion 4, where the material is laterally stretched. The long neck part 22 is cooled by the air of the outer blowing nozzle 5,
The throttle 18 serves as an air guide. At the same time, the long neck 2
The inside of 2 is cooled by cooling air coming out of the center of the die head 1. This cooling air enters and exits from the end of the pipe 26 that protrudes above the inner stabilizer 25 through a narrow gap with the inner stabilizer 25. The height-adjustable air nozzle wheel 7 is provided with a nozzle 8 before the lateral elongation of the material begins.
Are arranged so as to match the position of the long neck portion 22.

The measuring device 12 continuously measures the thickness of the completed film while rotating, and sends the measured value to the control device. The control device controls the valve 11 according to the thickness obtained,
As a result, the air amount of the nozzle 8 is controlled. The cooling capacity of the outer blowing nozzle 5 and the end region of the long neck portion 22 is as follows:
The cooling capacity of the outer blowing nozzle 5 is at least 10 times, preferably 2 times, the cooling capacity of the end region of the long neck portion 22.
It is set to be 0 times. In the end region of the long neck portion 22, the cooling capacity of the air nozzle group wheel 7 is preferably equal to or smaller than the cooling capacity of the cooling air flowing around the inner stabilizer 25.

If desired, the inner stabilizer 25 can be provided with a group of air nozzles having radially outwardly directed nozzles. In this case, the pipe 26 is formed as a double pipe through which the cooling air of this nozzle flows,
Or spill as shown. Since the measuring device 12 is arranged only immediately above the extension 4, signal processing is performed with a small dead time. That is, the signal processing is performed within a time that is not longer than the time when the material moves from the air nozzle group wheel 7 to the measuring device 12. If the inner stabilizer 25 has a group of air nozzles as described above, the flow rate through the individual nozzles is similarly controlled according to the measurement result of the measuring device 12. The heights of the inner stabilizer 25 and the air nozzle group wheel 7 can be adjusted so as to match the height of the end of the long neck portion 22. The radial adjustment of the nozzle 8 also makes it possible to adapt to different diameters of the tubular film at the end of the long neck.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the accompanying drawings.

[Brief description of the drawings]

FIG. 1 is a schematic view of a blowing part of a film manufacturing apparatus.

FIG. 2 is an enlarged sectional view of a die head portion.

FIG. 3 is a schematic view of a blowing part of a film manufacturing apparatus according to another embodiment.

[Explanation of symbols]

 Reference Signs List 1 die head 2 ring nozzle 3 tubular film 5 outer blowing nozzle 7 air nozzle group 8 nozzle of air nozzle group 12 measuring device 22 long neck 25 inner stabilizer

Continued on the front page (72) Inventor Manfret Gerner Germany 8900 Augsburg 22 Neudekerstrasse 13 (72) Inventor Andres Gumpert Germany 8900 Augsburg 22 Rungestrasse 22 (56) References JP JP-A-49-88954 (JP, A) JP-A-57-174214 (JP, A) JP-A-3-150128 (JP, A) JP-A-55-84632 (JP, A) JP-B-52-23365 (JP, A) , B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 55/28

Claims (4)

(57) [Claims] 1. A thermoplastic resin comprising a die head (1) having a ring nozzle (2) and an outer blowing nozzle (5), and a measuring device for measuring the film thickness of a tubular film (3). The tubular film manufacturing apparatus according to (1), wherein the tubular film (3) forms a long neck portion (22) before its expansion, and an end region of the long neck portion (22) is provided with the tubular film (3). An air nozzle group wheel (7) facing outward and an inner stabilizer (25) constituting an inner stabilizer (20) located in this region are arranged, and the measuring device (12) is arranged. The air flow passing through the nozzle (8) of the air nozzle group (7) is controlled in accordance with the measurement result of (1). Further, a cooling device is provided inside the die head (1), and the inside of the die head (1) is stabilized. Body (2 The outer diameter of) is formed slightly smaller than the inner diameter of the tubular film in the region of the inner stabilizing member (25), wherein the inner stabilizing member cooling capacity of the air nozzle group wheels (7)
The same or smaller than the cooling capacity of the cooling air in the area
A tubular film manufacturing apparatus configured as described above . 2. A cooling capacity of the outer blowing nozzle (5).
The force is the cooling capacity in the area of the air nozzle group (7).
2. The method of claim 1, wherein said at least ten times greater.
3. The apparatus for producing a tubular film according to item 1. 3. The internal stabilizer (20) introduces cooling air whose flow rate is adjusted according to the measurement result of the measuring device into the inside of the tubular film (3), and cleans the inner surface of the tubular film (3). The tubular film production apparatus according to claim 1 or 2, wherein the inner stabilizer (25) is provided with a nozzle group wheel capable of controlling cooling. Wherein said inner stabilizing member (25) is tube-shaped film production apparatus according to any one of claims 1 to 3 which is height-adjustable.