JPH1128764A - Method and apparatus for manufacturing inflation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a biaxially oriented film having transparency and high strength in various types. SOLUTION: The method for manufacturing an inflation film comprises the steps of bringing an outer peripheral surface of a melt tubular film 4 extruded from an annular die 1 into contact with an inner peripheral wall of a managing cooling cylinder 6a to cool temperature of the film 4 while managing it, then partitioning the film into an upstream side area and downstream side area at a partition of the pressurizing as a boundary by pressurizing an inner peripheral surface side of the film by a pressurizing board in which a pressurizing unit 8 is brought into contact with the inner periphery of the film, blowing hot air from its outer periphery to the film output to the downstream side via the partition to heat is so that the film is extended and oriented, and blowing extending and orienting air into the film to orient the film biaxially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing a thermoplastic synthetic resin film, and more particularly to a method and an apparatus for producing a blown film.

[0002]

2. Description of the Related Art Conventionally, a method for producing a blown film has been known. FIG. 11 is a schematic configuration diagram showing a conventional blown film manufacturing apparatus. The manufacturing apparatus 81 includes an extruder 82 for extruding a polymer, an annular die 84 attached to the extruder 82, an air ring 86 for cooling the tubular film 85, a guide plate 87 for folding the tubular film 85, and a take-off device 88. And a film winding device 89. The take-off device 88 includes a pinch roll 90 and a guide roll 91. In addition, the annular die 84
The air supply pipe 92 which feeds air for expanding the molten tubular film 85 under pressure is penetrated therethrough. The melting point of the resin is set to 100 from the annular slit 83 of the annular die 84.
The molten tubular film 85 heated to a temperature higher than about ° C. is extruded, air is blown into the molten tubular film 85 immediately after being extruded from the air supply pipe 92 to expand the molten tubular film 85, and the stretching temperature is increased by an air ring 86. Then, the film is cooled down and pulled in the machine direction by a take-off device 88 to achieve uniaxial stretching to produce an inflation film.

[0003]

However, the above-mentioned conventional apparatus and method for producing a blown film have the following problems. In the above-described apparatus, air is simply blown into the molten tubular film 85 immediately after being extruded from the annular die 84, so that the molten tubular film 85
In order to achieve biaxial stretching in the configuration shown in FIG. 11, the thickness of the film becomes uneven in the vertical and horizontal directions, and the film strength is different in the vertical and horizontal directions because the vertical and horizontal balance of the film is poor. When the pressurized air is sent downstream from the air ring 86, the pressurized air reaches the low-viscosity molten annular film 85 immediately after melting, and the diameter of the pipe becomes large before the start of the expansion and stretching. Can not. There is a problem that. Therefore, it was impossible to produce a biaxially oriented film having high strength and stable quality by the inflation film forming method.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for producing a blown film and an apparatus therefor, which can solve the above problems. An example of a specific purpose is as follows. (a) In the case of producing a film by biaxially stretching the tubular film as it is, eliminating the point where the stretching direction depends on the stretching direction of the take-up device, and achieving a balance that is not biased in any of the vertical and horizontal directions. To provide a biaxially stretched oriented film having high strength. (b) To provide a method and a manufacturing apparatus for manufacturing a transparent and high-strength biaxially stretched oriented film over a wide variety of products by controlling the biaxially stretched orientation and the resin gradient. (c) No need to change the material and properties of the thermoplastic synthetic resin,
In addition, a method and an apparatus which can use a conventional resin extruder or the like and can produce a transparent and high-strength biaxially oriented film by mounting some new jigs are provided. It should be noted that the problems of the invention other than those described above and the means for solving the problems will be described in detail in the description in the following specification.

[0005]

The present invention will be described with reference to FIGS. 1 to 10 showing an embodiment of the present invention, for example. The first invention is a method for producing an inflation film in which a molten tubular film is extruded from an annular die 1 having an annular slit 3 and air is blown into the molten tubular film through the annular die 1. A control cooling body 6 having a peripheral wall abutting on the outer peripheral surface of the film is provided outside the tubular film, and the temperature of the film resin is controlled and cooled by the control cooling body 6, and the inner peripheral surface of the film is formed inside the tubular film. A pressurizing body 8 having a peripheral wall that abuts on the tubular film is provided, and the tubular film held by the control cooling body 6 is pressurized by the pressurizing body 8, so that the tubular film is separated from the upper and lower parts by a partition by the pressurization. The tubular film is expanded by blowing hot air from the outer circumference to the tubular film that has come out to the upper side through the partition With heating to allow extension, and wherein the blowing extended draw air 9 into the interior of the tubular film.

A second invention is to extrude a molten tubular film from an annular die 1 having an annular slit 3,
In the method for producing an inflation film in which air is blown into a molten tubular film through an annular die 1, a controlled cooling body 6 having a peripheral wall in contact with an inner peripheral surface of the film inside the tubular film extruded from the annular die 1.
Is cooled while controlling the temperature of the film resin by the control cooling body 6, and a pressurizing body 8 having a peripheral wall abutting on the outer peripheral surface of the film is provided outside the tubular film. The tubular film is pressurized by the pressurizing body 8 to partition the tubular film into an upper portion and a lower portion at a partition by the pressurization, and to apply hot air from the outer periphery to the tubular film that has exited to the upper side through the partition. The method is characterized in that the tubular film is heated so that it can be stretched and stretched by spraying, and that the air 9 for expanding and stretching is blown into the inside of the tubular film. In addition, as the management cooling body 6 in the first invention, a management cooling cylinder 6a and the like can be exemplified, and as the pressurizing body 8, a pressurizing plate 8a can be exemplified. Further, the controlled cooling body 6 in the second invention can be exemplified by a managed cooling body 6ba having an outer peripheral wall, and the pressurized body 8 can be exemplified by a pressurized cylinder 8b.

A third invention is to extrude a molten tubular film from an annular die 1 having an annular slit 3,
In the method for producing an inflation film in which air is blown into the molten tubular film through the annular die 1, the inner peripheral surface or the outer peripheral surface of the tubular film extruded from the annular die 1 is brought into contact with the peripheral wall of the control cooling body 6. After cooling while controlling the temperature of the resin, the tubular film is pressed by the pressing body 8 from the film surface side opposite to the film surface in contact with the peripheral wall, so that the tubular film is separated from the partition by the pressure. The film is partitioned into an upstream region and a downstream region, and heated so that the tubular film can be expanded and stretched by blowing hot air from the outer periphery onto the tubular film that has come out downstream through the partition,
It is characterized in that the air for expansion and stretching 9 is blown into the inside of the tubular film.

A fourth aspect of the present invention is characterized in that the tubular film stretched and stretched by the stretching air is held on the inner peripheral wall of the stretching and holding cylinder 19. The apparatus for manufacturing a blown film according to the fifth invention comprises an annular die 1 for extruding a molten tubular film from an annular slit 3, an expansion-stretching air supply passage 52 for blowing air for expansion-stretching through the annular die 1, and an annular die 1. A management cooling body 6 that is installed on the downstream side and holds the tubular film by the peripheral wall to cool while controlling the temperature thereof, and a tubular film held in a peripheral wall of the management cooling body 6 in combination with the management cooling body 6 A pressurizing member 8 for pressing the film surface from the side opposite to the peripheral wall, an annular hot air blowing device 54 for blowing hot air from the outer periphery to the tubular film that has come out downstream through the pressurization by the pressurizing member 8, and an annular hot air An expansion and stretching holding cylinder 19 for holding an expansion and stretching tubular film that has been expanded and stretched by heating by the blowing device 54 and blowing in the expansion and stretching air 9. It is characterized in.

In a sixth aspect of the present invention, the management cooling body 6 is a management cooling cylinder 6a provided outside the tubular film.
It is characterized in that the pressing body 8 is a pressing plate 8a which comes into contact with the inner peripheral surface of the tubular film. The seventh invention is characterized in that the control cooling body 6 is provided inside a tubular film, and the pressurizing body 8 is a pressurizing cylinder 8b abutting on the outer peripheral surface of the tubular film. The eighth invention is characterized in that the pressing body 8 includes a heating means. The ninth invention is characterized in that an auxiliary air supply passage 53 capable of supplying auxiliary air 64 is provided through the annular die 1 inside the molten tubular film 4 from the annular die 1 to the control cooling body 6. The tenth invention is based on the diameter of the peripheral wall of the management cooling body 6,
It is characterized in that the pressure body 8 has a diameter difference in the range of 5 mm to 1 mm, and a pressure resistance is given to the tubular film held on the peripheral wall of the control cooling body 6 by the diameter difference.

According to an eleventh aspect of the present invention, an auxiliary air 64 supplied to the inside of the molten tubular film 4 and expansion / expansion air 9 for expanding / expanding the tubular film are applied to the control cooling body 6 by applying a pressurizing body 8. It is characterized in that the film is produced by applying pressure to cut off the pressure so that one air pressure does not affect the other air pressure. Twelfth
The present invention sets the diameter of the control cooling body 6 in the range of 0.7 to 2.3 times the diameter of the annular slit 3 of the annular die 1 and brings the tubular film into close contact with the control cooling body 6. Characterized in that the stretching is performed.

According to a thirteenth aspect, a gradient is provided by making the diameter of the outlet and the diameter of the inlet of the management cooling body 6 different from each other.
It is characterized in that the tubular film has a take-up resistance. The fourteenth invention is characterized in that a raised peripheral portion 62 is provided on a peripheral wall of the management cooling body 6 where the tubular film contacts, and the convex peripheral portion 62 controls the take-up resistance of the tubular film. The fifteenth invention is characterized by increasing the frictional resistance of the expansion / stretch holding cylinder 19 by making the upstream diameter of the expansion / stretch holding cylinder 19 smaller than the downstream diameter. The contents of the first to fifteenth inventions described above can be implemented by combining any one of the contents of the invention with at least one invention other than the invention.

[0012]

According to the first and second aspects of the present invention, since the temperature of the tubular film resin extruded from the annular die 1 can be controlled and controlled by the control cooling body 6, the temperature can be controlled to the most suitable temperature for the extension and stretching. As a result, the gradient and crystallization of the resin before the extension and stretching can be controlled. Further, in the temperature controlled state, the pressing body 8
, The tubular film is partitioned into an upper part and a lower part, so that the expansion / stretching air 9 blown at the upper side does not reach the lower side where the control cooling body 6 is located. That is, since the air for expansion and stretching does not flow toward the molten resin as in the conventional apparatus shown in FIG. 11, the film diameter before expansion and stretching does not increase. Furthermore, the tubular film that has come out to the upper side through the partition is heated so that it can be extended and stretched by blowing hot air from the outer periphery thereof, and the air 9 for extended stretching is blown into the inside of the tubular film. Stable stretching can also be performed in a transverse direction that is substantially orthogonal. As described above, according to this production method, biaxial stretching orientation can be realized, and a blown film having high strength can be produced. Here, in this manufacturing method, since the pressurizing body is provided, the tubular film has a vertical direction,
In the case of stretching biaxially in the horizontal direction, stable braking can be obtained in the vertical and horizontal directions, and the quality of biaxial stretching can be improved. Further, since the pressurizing member can be constituted by a simple and inexpensive member such as a pressurizing plate and a pressurizing cylinder, there is an advantage that a biaxially stretched film can be manufactured at low cost.

According to the third aspect of the present invention, the present invention can be applied not only to a configuration in which the tubular film flows from the lower side to the upper side, but also to a configuration in which the tubular film flows from the upper side to the lower side. The basic operation and effects are substantially the same as those of the first and second inventions. According to the fourth aspect of the invention, since the expanded and stretched tubular film is held on the inner peripheral wall of the expanded and stretched holding cylinder 19, the fluctuation and the like of the expanded and stretched tubular film are suppressed, and a uniform and stable film having properties is obtained. Can be provided. According to the fifth aspect, the molten tubular film extruded from the annular die 1 is held by the peripheral wall of the management cooling body 6 installed on the downstream side of the annular die 1 and cooled while controlling its temperature. This makes it possible to accurately control the orientation and crystallization of the resin immediately before the expansion and stretching of the molten tubular film. When the film surface of the tubular film is pressurized by the pressurizing body 8, the tubular film is partitioned into an upstream area and a downstream area, and the expansion and stretching air 9 performed in the downstream area is controlled by the control cooling body 6. So that it does not reach the upstream area with That is, since the air for expansion and stretching does not flow toward the molten resin as in the conventional apparatus shown in FIG. 11, the film diameter before expansion and stretching does not increase. Then, the annular hot air blowing device 54 blows hot air from the outer periphery of the tubular film to the downstream side through the pressurization by the pressurizing member 8 and the annular die 1 from the expansion / stretching air supply path 52.
, The tubular film can be biaxially stretched by blowing air for expansion and stretching. Therefore, also in the fifth invention, it is possible to produce a biaxially oriented film having stable properties and characteristics which could not be produced conventionally. Further, the braking pressure of the pressurizing member 8 acts in two directions, a longitudinal direction which is a method of moving the tubular film, and a lateral direction which expands by blowing the expansion / stretching air 9. There is an advantage that the quality of the expanded and stretched tubular film is improved.

As in the sixth invention, the control cooling body 6 is a control cooling cylinder 6a provided outside the tubular film, and the pressurizing body 8 is a pressurizing plate 8a contacting the inner peripheral surface of the tubular film. Experiments have confirmed that the adoption of the above configuration is preferable in the case of producing a resin having high melt elasticity, for example, medium-low pressure polyethylene. By adopting a configuration in which the control cooling body 6 is provided inside the tubular film and the pressurizing body 8 is a pressurizing cylinder 8b abutting on the outer peripheral surface of the tubular film as in the seventh invention, Experiments have confirmed that this is preferable when producing a resin having low elasticity, for example, polyamide, polyethylene terephthalate, ultra-thin low-pressure polyethylene and the like. According to the eighth aspect, since the pressurizing member 8 includes the heating means, when the temperature of the softened tubular film is increased to a temperature required for the expansion and stretching, heat can be supplied from the heating means in addition to the temperature rise by the hot air. Therefore, a stable temperature rise can be achieved.

According to the ninth aspect, the auxiliary air 64 is provided inside the molten tubular film from the annular die 1 to the control cooling body 6.
Can be supplied, so that the close contact between the management cooling body 6 and the tubular film can be controlled by the auxiliary air 64. When the control cooling body 6 is provided outside the tubular film, it is preferable to use the auxiliary air 64 in order to bring the outer peripheral surface of the molten tubular film into close contact with the inner peripheral wall of the control cooling body 6.
Further, when the control cooling body 6 is inside the tubular film, the inner peripheral surface of the molten tubular film naturally adheres to the outer peripheral wall of the control cooling body 6 due to the neck-in effect due to the normal pressure generated by the viscoelasticity of the molten tubular film. Because of the close contact, the blowing of the auxiliary air 64 can be used to control the degree of close contact.

According to the tenth aspect, since a pressure resistance is given by the difference in diameter, partitioning can be performed with a simple configuration, and the expansion / extension air 9 does not affect the upstream side of the control cooling body 6. Can be According to the eleventh aspect, since the partitioning is performed by pressurizing the pressurizing body 8 with respect to the control cooling body 6, even if there is a considerably large pressure difference between the auxiliary air 64 and the expansion / extension air 9, the Air pressure does not affect the other air pressure. According to the twelfth aspect, the diameter of the control cooling body 6 is 0.7 times to 2.3 times the diameter of the annular slit 3 of the annular die 1.
By setting it in the double range, it is possible to maintain good film take-up and adhesion.

According to the thirteenth aspect, an appropriate tubular film take-up resistance can be provided with a simple structure, and stable and uniform cooling by the control cooling body 6 can be achieved. According to the fourteenth aspect, with a simple configuration in which the convex peripheral portion 62 is provided, the take-up resistance of the tubular film is controlled,
Stable and uniform cooling in the management cooling body 6 can be achieved. According to the fifteenth aspect, it is possible to suppress the swing of the expanded stretched film by increasing the frictional resistance of the expansion stretch holding cylinder 19. As described above, according to the present invention described above, it is possible to develop a method and apparatus for controlling the biaxial resin gradient, which cannot be achieved by the conventional inflation film forming method shown in FIG. Was. According to the present invention,
It is possible to provide a high-quality biaxially oriented film having a uniform thickness and excellent strength in the vertical and horizontal directions. Furthermore, by combining with the recent multilayer extrusion technology, it is possible to economically produce a thinner and stronger film for use in bags, packaging materials, packaging materials, and the like than before. Further, the present invention can be implemented by attaching a new jig such as the management cooling body 6, the pressurizing body 8, the hot air blowing device 54, and the expansion / stretch holding cylinder 19 to a conventional inflation film forming apparatus, so that the cost is low. Also,
ADVANTAGE OF THE INVENTION According to this invention, there exists an advantage that not only the resin type which is not on the market but also a conventionally-known synthetic resin can be used to produce a unique new film product.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of a blown film manufacturing apparatus according to a first embodiment of the present invention, and FIG.
FIG. This manufacturing apparatus is roughly divided into an annular die 1 for extruding the molten resin 2 in order from the upstream side when viewed from the traveling direction of the tubular film 35, a controlled cooling body 6 for cooling while controlling the temperature of the tubular film 35, a tubular film 35. The structure includes a pressurizing body 8 that pressurizes 35, an expanded extension portion 51 that expands the tubular film 35 with pressurized air, and heats the tubular film 35 from the outer periphery with hot air 40 (see FIG. 2). In addition, the tubular film 35 becomes the molten tubular film 4 when the molten resin 2 is extruded from the annular slit 3 of the annular die 1, and becomes the softened tubular film 7 by being brought into contact with the management cooling body 6 and being managed and cooled, which is not shown. An expanded stretched tubular film 10 is formed by the stretching force of the take-up device and the expansion stretching of the expansion stretching air 9. The extended extension portion 51 includes the outer cylinder 2
An expansion-stretching holding tube 19 for holding the expansion-stretching tubular film 10 is arranged inside 1, and a hot-air blowing device 54 is attached to a bottom wall 56 of the outer tube 21.

The annular die 1 is mounted on a resin extruder (not shown). The annular die 1 includes an annular slit 3 through which the molten resin 2 is extruded, an expanded air supply pipe 52 to which the expanded air 9 is supplied, and an auxiliary air supply pipe 53 to supply auxiliary air 64. The extended stretch air supply pipe 52 and the auxiliary air supply pipe 53 are formed by the annular slit 3.
It is provided inside. An air ring 5 for cooling the molten tubular film 4 extruded from the annular die 1 by wind is provided above the annular die 1. Further, a pressurizing plate 8 a as an example of the pressurizing body 8 is provided upright at the upper position of the annular die 1. The pressing plate 8a is formed in a disk shape, and the outer peripheral wall of the pressing plate 8a presses the tubular film 35 from the inner peripheral surface side. The extended expansion air supply pipe 52 penetrates through the pressure plate 8a, and the compressed air port 18 of the expansion expansion air supply pipe 52 is provided on the upper wall of the pressure plate 8a.

The control cooling cylinder 6a is arranged so that the outer peripheral wall of the pressurizing plate 8a is fitted at the downstream position. The management cooling cylinder 6a is shown as an example of the management cooling body 6. A temperature control medium 57 such as water is circulated in the management cooling cylinder 6a. The temperature control medium supply pipe 31 for introducing the temperature control medium 57 into the management cooling cylinder 6a, and the management cooling cylinder 6a
And a temperature control medium recovery pipe 32 for discharging a temperature control medium 57 from the apparatus. The tubular film 35 sandwiched between the control cooling cylinder 6a and the pressure plate 8a is pressed by the pressure plate 8a. As shown in FIG. 2, an elastic ring 41 is mounted on the outer peripheral wall of the pressure plate 8a, and the ring 41 presses the tubular film 35 to separate (seal) it.

Next, the specific configuration of each component will be described. The hot air blowing device 54 is provided with the management cooling cylinder 6a,
The pressurizing plate 8a is provided in an annular shape so as to surround the outer periphery thereof, and the hot air blowing device 54 is connected to the bottom wall 56 of the outer cylinder 21. The annular hot-air outlet 16 of the hot-air blowing device 54 is for heating the tubular film 35 from the outer periphery, and is configured to guide the outside air taken in from the outside air inlet 22 to the annular hot-air outlet 16 through the air passage 13a. . That is, the hot air blowing device 54 guides the outside air into the air passage 13 a by the blower 12, turns the air into hot air by the electric heater 14, manages the temperature in the air passage 13 a by the thermocouple 15, and controls the air passage 13 a by the buffer tube 58. By changing the flowing hot air into rectification corresponding to the annular hot air outlet 16, uniform dynamic pressure and static pressure are obtained, and a desired air volume is obtained. In the configuration shown in FIGS. 1 and 2, a fine control heater 17 is provided in order to keep the temperature of the tubular hot air outlet 16 constant. In the configuration shown in FIG. 1, the management cooling cylinder 6a and the hot air outlet 1
6, an annular auxiliary heater 55 is provided.
The auxiliary heater 55 is not always necessary, but is provided as needed.

A bottom wall 56 in the outer cylinder 21 has an extended extension 51
An annular extended portion ensuring heater 36 for guaranteeing the temperature in the inside is provided. Further, an annular buffer space portion 25 is provided in the outermost peripheral area of the bottom wall 56, and the buffer space portion 25 is provided with the circulation recovery port 23 that draws in the heated air of the expansion extension portion 51. The heating air in the outer cylinder 21 is sucked into the blower 12 through the buffer space 25 and the air passage 13b. Inside the outer cylinder 21, an extended extension holding cylinder 19 is arranged concentrically with the center axis of the outer cylinder 21. Further, an annular heating device 20 is externally fitted to the expanded and stretch holding cylinder 19 at an upstream position, and an annular cooling device 37 is externally fitted to a downstream position thereof. A boundary peripheral groove 28 is provided between the heating device 20 and the cooling device 37.

As the heating device 20, a device that heats by induction heat generation or a temperature control medium liquid can be adopted, and as the cooling device 37, for example, a configuration that circulates cooling water can be adopted. Outer cylinder 21, heating device 20 and cooling device 3
7, a partition cylinder 29 is provided. Partition cylinder 2
9, the annular air passage 59 can be formed between the partition cylinder 29 and the outer cylinder 21 and the annular air passage 59 can be formed.
Can be prevented from being affected by the heating device 20 and the cooling device 37 mutually. In addition, the extension and extension holding cylinder 1
9 is located downstream of the circulation recovery port 23, the hot air from the annular hot air outlet 16 is in a state where the expanded stretched tubular film 10 is held by the expanded stretch holding cylinder 19. After the tubular film 35 is heated, it is branched into hot air recovered from the circulation recovery port 23 and hot air flowing toward the environment holding outlet 24.

FIG. 3 is a schematic longitudinal sectional view showing a second embodiment of the present invention. In the first embodiment, the management cooling body 6 is a management cooling cylinder 6 a provided outside the tubular film 35, and the pressurizing body 8 is a pressure plate 8 a contacting the inner peripheral surface of the tubular film 35. The configuration shown is
In the second embodiment, the control cooling body 6b is provided inside the tubular film 35, and the pressing body 8 is
5 is different from that of FIG. Furthermore, in the second embodiment, the management cooling body 6
b is disposed inside the tubular film 35, so that the supply pipe 31 for supplying the temperature control medium 57 and the recovery pipe 3
Numeral 2 is configured to communicate with the outside through an annular die 1. In the second embodiment, the configuration of the extension and extension portion 51 and the like is substantially the same as in the first embodiment.

FIG. 4 is a diagram showing the ratio of the length of each component when the diameter D of the annular slit 3 of the annular die 1 is set to the reference length 1.0, taking the second embodiment as an example. The range of the length of each component is preferably set as follows. Distance E between annular die 1 and control cooling body 6 E = 2.5D
~ 3.5D Diameter G of inlet side of management cooling body 6 = 0.7D ~ 2.3D Length F from entrance to outlet of management cooling body 6 = 0.5D ~
2.0D In addition, the length J of the extended stretch holding cylinder 19 is set to be from 0.5 K to 0.67 K with respect to the diameter K of the stretched tubular film 10. In FIG. 4, the position indicated by (I) is the position where the molten resin 2 exits from the annular slit 3, and (I)
The position shown in I) is the position of the inlet of the controlled cooling body 6, the position shown in (III) is the position of the outlet of the controlled cooling body 6, and the position shown in (IV) is the position of the expanded stretched film 10 that has been expanded and stretched. . The lengths of A and B in FIG. 4 will be described later.

Next, with reference to the structures of the first and second embodiments shown in FIGS. 1 and 2, the characteristic structure and operation of the blown film manufacturing method and the blown film manufacturing apparatus of the present invention will be described in more detail. explain. First, in FIGS. 1 and 2, the molten tubular film 4 is extruded into the atmosphere from the annular slit 3 of the annular die 1, and is brought into contact with the inlet of the control cooling body 6 while cooling the molten tubular film 4 by the air ring 5. Here, the annular die 1
The temperature of the molten resin 2 coming out of the resin is +100 of the melting point of the resin.
It is about ° C. Naturally, the resin at this time has no orientation or crystallinity, and the thickness of the film is, for example, about 2 m.
m to about 0.5 mm.

(1) Operation of Controlled Cooling Body When the molten tubular film 4 reaches the inlet position (indicated by (II) in FIG. 4) of the controlled cooling body 6 shown in FIGS. 1 and 2, FIG. As shown in FIG. 5, when the temperature range between the resin melting point and the resin softening point is divided into three equal parts, the temperature range is ／ of the softening point below the resin melting point (indicated by the dashed hatched area 66 in FIG. 5). Set to be. At this time, the resin of the molten tubular film 4 has no orientation or crystallinity, and the thickness of the film is, for example, about 1 mm to 0.25 mm.

The molten tubular film 4 is then cooled by the control cooling body 6, and at the outlet position of the control cooling body 6 (see (III) in FIG. 4), a temperature range of 1/3 of the melting point side above the softening point (see FIG. 4). 5 is indicated by a dashed line area 60). By this rapid cooling, the resin is microcrystallized, and the resin is ready for extended stretching. In addition, in the case of the configuration shown in FIG. 1, the molten tubular film 4 adheres to the inner peripheral wall of the control cooling cylinder 6a by supplying auxiliary air from the auxiliary air supply pipe 53 of the annular die 1 into the molten tubular film 4. Then, the molten tubular film 4 is uniformly transferred to the softened tubular film 7. In the case of the configuration shown in FIG. 2, the molten tubular film 4 has a tubular film diameter expanded to the diameter of the control cooling body 6 b and is brought into close contact with the outer peripheral wall of the control cooling body 6 b, so that the molten tubular film 4 is uniformly formed. To the softened tubular film 7. By these actions, the molten tubular film 4 increases the hardness and viscoelasticity, and converts the softened tubular film into a pressure of 59 mAq to 8 mAq in terms of the pressure of the pressing plate 8 a (see FIG. 1) or the pressing cylinder 8 b (see FIG. 2). Can be pressed.

(2) Preferred Structure of Controlled Cooling Body It is preferable that the managed cooling body 6 be made of pig iron or pig iron coated with copper. Also, Sandplast # 240 ± 60
, The softened tubular film 7 is uniformly cooled, and can be maintained in a state free from scratches due to contact. In addition, you may coat | cover the management cooling body 6 with a natural fiber as needed. The control cooling body 6 can change the diameter of the film inlet (upstream port) and the diameter of the film outlet (downstream port) on the peripheral wall with which the film contacts, and make a gradient so as to connect those diameters. preferable. Specifically, after determining the length F of the management cooling body 6 shown in FIG. 4, as shown in FIG.
1.7% to 7.6% of the outlet diameter with respect to the inlet diameter
It is preferable that the diameter of the outlet is reduced by 1.7% to 7.6% with respect to the diameter of the inlet of the control cooling cylinder 6a as shown in FIG.

By providing this gradient, the discharge amount of the film varies, the internal pressure of the molten tubular film 4 varies, the thermoelasticity of the resin of the molten tubular film 4 varies, the take-up speed varies, and the expanded portion of the tubular expanded stretched film 10 increases. 11 can be suppressed. By suppressing these fluctuations, the cooling from the molten tubular film 4 to the softened tubular film 7 can be made uniform, and the production of the inflation film can be controlled to be constant, and finally the uniform inflation can be achieved. Film can be manufactured. The gradient varies depending on the required film width and film thickness. That is, the gradient must be smaller as the film width is smaller and the film is thinner, and the gradient is larger as the film width is larger and the film is thicker.

However, due to a problem in resin properties from the molten tubular film 4 to the softened tubular film 7, if the gradient is increased beyond 7.6%, the performance of the expanded film cannot be sufficiently exhibited. If it is less than 1.7%, the purpose of braking cannot be achieved. Depending on the type of resin to be formed, the sway of the molten tubular film may be large, but in order to compensate for the shortage, as shown in FIGS. 6 (A) and 6 (B), the longitudinal section has a substantially hemispherical shape. By providing the convex peripheral portion 62 having a semi-waterdrop-shaped vertical cross section as shown in FIG. 6C, the take-up resistance can be increased and the ejection and the take-up film can be prevented from shaking. In this case, as shown in FIG. 6B, the height h of the convex peripheral portion 62 from the peripheral surface 63 is 0.3 m.
It is preferable to set the range of m to 4.9 mm. In addition,
FIG. 6 shows the case of the first embodiment, but it goes without saying that in the second embodiment, the convex peripheral portion 62 is provided on the outer peripheral wall of the management cooling body 6b.

(3) Regarding the contrivance of the temperature for increasing the softening degree of the tubular film, as described above, the temperature of the tubular film at the outlet position of the control cooling body 6 (the position (III) in FIG. 4) is as shown in FIG. Is controlled within the temperature range indicated by the dashed-dotted hatched portion 60. The temperature of the softened tubular film 7 is raised to a temperature in a range of 3/6 to 5/6 on the melting point side above the softening point as shown by a solid hatched portion 61 in FIG. It was confirmed by an experiment that biaxial stretching of satisfactorily was performed. The hot air 40 from the annular hot air outlet 16 controlled to be heated in that temperature range.
While the heating is performed, the expansion and stretching are performed by introducing the expansion and stretching air 9 and pulling in the longitudinal direction.

(4) Adoption of a partition by pressurization When performing the extension stretching, if the pressurizing member 8 is not provided,
The pressure of the expansion / stretching air 9 blown into the expanded / stretched film 10 flows out to the management cooling body 6 side, and the softened tubular film 7 that is in close contact with the management cooling body 6 is separated, and the cooling by the management cooling body 6 and In some cases, lateral stretching cannot be performed. Therefore, in the present invention, the film is pressurized by the pressurizing body 8 paired with the control cooling body 6,
A partition is provided so that the pressure of the expansion / stretching air 9 in the expansion / stretching film 10 does not flow out to the control cooling body 6 side. This partition can be said to be a seal having a predetermined strength.

(5) Types of Partitions There are a method of partitioning by pressurizing only hot air from the annular hot air outlet 16 and a method of partitioning by the pressurizing body 8 paired with the management cooling body 6. Without using the pressing body 8,
The method of partitioning only with hot air can be used for forming a thin film. (6) Configuration of Pressing Body By using an elastic body as the pressing body 8, it is possible to improve the confidentiality at the film contact portion. Also, by making the pressing body 8 elastic, for example, the thickness of the film is reduced from 200 μm to 5 μm.
In the range of 0 micron, the setting of the pressurizing body 8 can be made constant, and it is not necessary to perform complicated pressure setting, which is convenient. As a typical example of the structure of the pressing body 8, a configuration in which a metal cylinder is coated with silicon rubber or fluorine rubber having a hardness of 60 to 75 degrees can be exemplified.

In general, silicone rubber and fluorine rubber are provided on the peripheral wall of the pressure member 8 in a ring shape. In addition, a ring having hollow air inside, a ring coated with an elastic natural fiber material or the like can be used, or an elastic body made of an integrated pressurized material such as a paper material or a natural fiber material can be used. The pressurizing body 8 provided can also be employed. The pressurizing body 8 can be configured to include a heating means inside as necessary. Examples of such a heating unit include a configuration in which a commercially available jig such as an electric heater and an induction heating ring is incorporated, and a configuration in which a temperature control medium is circulated. By using the pressurizing body 8 provided with such a heating means, the temperature of the tubular film can be uniformly raised in a short time,
There is an effect that the resin thermoelasticity of the film can be made uniform. Further, by providing the heating means, there is an advantage that the pressurizing pressure of the pressurizing body 8 can be stabilized and the necessary pressurizing pressure can be reduced.

In the configuration shown in FIGS. 1 and 2, the diameter of the peripheral wall of the control cooling body 6 and the diameter of the pressurizing body 8 are 5 mm to 1 mm.
It is assumed that there is a diameter difference within a range of mm, and the pressure difference is applied to the tubular film held on the peripheral wall of the control cooling body 6 by the diameter difference. That is, a predetermined pressure resistance is applied to the tubular film by the deformation of the elastic body of the pressure body 8. As shown in FIG. 7, in a configuration in which the diameter L1 of the pressurizing cylinder 8b is smaller than the outlet diameter L2 of the control cooling body 6b, the pressurizing cylinder 8b
It is also possible to displace the pressurizing cylinder 8b to the downstream side so as not to fit outside.

(7) Specific Examples of Partition by Hot Air and Partition by Pressing Body Note that, depending on the type of film, the annular hot air outlet 1
It is also possible to perform partitioning only with the hot air from 6 or to use both pressurization by the pressurizing body 8 and hot air. In addition, by performing the pressurization by the pressurizing member 8, the film pressurization resistance due to the hot air can be reduced. In the case of a film having a thickness of 100 microns or less, a pressurizing body 8 having a heating means therein.
It is preferable to use hot air from the annular hot air outlet 16 in combination. For a film having a thickness of 60 μm or less, film production can be achieved by using the pressurizing body 8 and hot air together or in a selective manner. On the other hand, in the formation of a film having a thickness of 20 μm or less, the partition can be achieved only by the pressure resistance of the hot air from the tubular hot air blow-out port 16 which is controlled in heating without using the pressing body 8.

(8) Details of hot air blown from annular hot air outlet 16 As shown in FIGS. 1 and 2, the lip diameter of annular hot air outlet 16 is 15 mm or more from the diameter of the outlet of control cooling body 6. 77
The diameter is wide in the range of mm. The gauge pressure of hot air is
It has been found by experiments that if the pressure is in the range of 0.009 MPa to 0.035 MPa, the influence of the auxiliary air 64 supplied into the molten tubular film 4 and the effect of the expansion / stretching air 9 can be cut off by the pressure of the partition. The internal pressure of the expanded stretched air 9 of the expanded stretched film 10 is 0.001.
Experiments have confirmed that when the pressure is 0.0037 MPa or more, the movement for taking up the tubular film is stopped. Furthermore, in the hot air from the diameter of the tubular lip which is 78 mm or more larger than the diameters of the control cooling body 6 and the pressurizing body 8, the relation of lip width × circumference × air volume is:
Since the hot air is diffused, and the blow in the expanded stretched portion 11 of the stretched stretched film 10 fluctuates, a problem occurs in that unevenness occurs in the heating temperature of the tubular film. Therefore,
As a result of many experiments, the static air pressure in the hot air lip was set to 8 mA.
0.009 to 0.035 in the range of q to 59 mAq.
The result that the film pressure of MPa can be achieved was obtained. In order to obtain this condition, the capacity of the blower must be set at a static pressure of 74.
90 cubic meters / min in the range of mAq to 9 mAq to 2.1
It can be achieved at cubic meters / minute. Further, in a configuration having a pressurizing body, 0.009MP
In order to achieve a film pressure of a to 0.035 MPa, in the case of an elastic pressing body, 0.73 kg / cm ²
It was found that setting to ~ 5.78 kg / cm ² is sufficient.

(9) Regarding the configuration of the portion where the hot air from the annular hot air blow-out port raises the temperature of the tubular film and the portion where the tubular film is expanded and stretched, the above two portions are the same as those described above in the present embodiment. This is performed by the unit 51. Hereinafter, this configuration will be described. When the tubular film by hot air reaches a predetermined temperature and the stretching air is supplied to the inside of the tubular film in preparation for the stretching, the tubular film is stretched in the longitudinal direction by pulling and the transverse direction of the stretching air. Is stretched biaxially. Then, the tubular film expands the expanded stretch diameter and expands the stretch stretch holding cylinder 19.
Touch The diameter of the expansion / stretch holding cylinder 19 is set to the film folding width.

(10) Installation of Extended Stretch Assurance Heater The hot air from the annular hot air outlet 16 is
In order to overcome the problem of hot air diffusion and the problem of the hot air temperature becoming unstable in the expansion and stretching section 51 until the diameter of a predetermined size is reached, diffusion and stretching assisting hot air The heater 36 was installed on the bottom wall 56. By installing the diffusion stretching ensuring heater 36, the temperature of the expanded portion 11 of the expanded stretched film 10 can be made substantially uniform, and can be maintained at a preferable temperature for the stretch stretching. Further, by collecting the hot air from the circulation recovery port 23 as described above, the convection of the hot air can be maintained in the cylinder. On the other hand, when trying to heat the tubular film only with hot air, stretching irregularities such as temperature irregularities, diffusion irregularities, and wind pressure irregularities occur. Further, if the tubular film is heated only by the heater without using hot air, unevenness of the surface temperature of the induction heating ring, the electric heater or the like causes unevenness in the tubular film. Further, in the first and second embodiments, the inside of the expansion / stretching holding cylinder 19 is maintained at a slightly positive pressure by the hot air 40 and the diffusion / stretching assurance heater 36 to stably suppress various spots. Heating is to be achieved.

(11) Flow of Heated Air in the Outer Cylinder Regarding the convection, if the amount of air blown from the blower tube 13 is 1, the amount of hot air recovered from the circulation recovery port 23 is 4/5. It is preferable to set the range so as to fall within the range of １ ／, and make up the shortage with fresh air in the outside air intake 22. After the convection of the hot air supplied by the annular hot air outlet 16, a part of the hot air flows into an environment holding outlet 24 toward a guide plate (not shown) for folding the film.
It is naturally discharged as. The discharged air is very effective in maintaining the quality at the time of folding, particularly for forming a hard film.

(12) Configuration for Preventing Minute Fluctuation of Expanded Stretched Tubular Film Held in Extended Stretch Holding Tube For the purpose of preventing the above minute fluctuation in the stretch stretching holding tube 19, the present invention provides: For example, as shown in FIG. 2, the diameter of the inlet 26 of the extension / stretch holding cylinder 19 is
The diameter of the outlet 27 of No. 9 was widened in the range of 6, 5% to 1.2% to give pulling resistance to the tubular film, thereby suppressing the fluctuation of the film. In addition, as described above, the cylindrical heating device 20 is mounted on the outer periphery of the inlet side of the extension / stretch holding tube 19, and the cylindrical cooling device 37 is mounted on the outer periphery of the outlet side of the extension / holding tube 19. A boundary peripheral groove 28 is provided from the outer peripheral side. With such a configuration, the heating region corresponding to the region where the heating device 20 is provided and the cooling region corresponding to the region where the cooling device 37 is provided can be clearly partitioned, and the retained expanded stretched film 1 is held.
There is an effect that the fluctuation of 0 can be suppressed or prevented. Further, a partition tube 29 is provided between the outer tube 21 and the extension / stretch holding tube 19.
Is provided between the partition cylinder 29 and the outer cylinder 21.
Providing the heating and cooling device 3 of the heating device 20
7 is effective in maintaining good cooling, and is also effective in suppressing the fluctuation of the held expanded stretched film 10. Further, the film contacting surface of the extension / stretch holding cylinder 19 is made of Sandplast # 240.
By setting the surface in the polished state in the range of 0, it was possible to maintain a contact state in which there is no particular problem in the film lifting operation.

(13) In the present invention, an example of a configuration capable of sufficiently exhibiting performance will be described. First, A = [diameter of stretched tubular film−diameter of unstretched tubular] / 2 in FIG. 4 indicates transverse stretching, and B in FIG. 4 from the start of stretching (the upper surface of the outlet of the control cooling body 6) to the end of the stretching extension point. Indicates the longitudinal stretching. Here, the stretching gradient = B ÷ A, and the vertical and horizontal stretching magnification difference = B−A. Depending on the blow ratio of the molten tubular film, it is possible to achieve 3.2 to 3.5 times the stretching and gradient of each resin type. Further, it is possible to develop an extended stretching technique by an inflation film forming method, which can set the difference in the stretching ratio in the vertical and horizontal directions in the range of 0.5 to 1.2, and achieve the stretching gradient in the range of 1.2 to 1.4. Was.

[0044]

EXAMPLES A typical example of the present invention will be described, and a comparative example with a conventional method will be described. (Example 1) Resin High-density polyethylene (commercially available)
MI3.5 Density 0.956 Vicat Softening point 127 ° C Annular slit diameter D = 200mm Management cooling cylinder ratio G = l. 6 (G = 1.6D = 3
20mm) Film thickness 15 microns Film forming result is good

Example 2 Resin High-density polyethylene (commercially available)
MI3.2 Density 0.950 Vicat Softening point 125 ° C Annular slit diameter D = 200 mm Management cooling cylinder ratio G = l. 6 Film thickness 15 microns Film forming result good (Example 3) Resin Polystyrene (commercially available) Ml
4.1 Density 1.05 Vicat Softening point 98 ° C Annular slit diameter D = 200mm Control cooling cylinder ratio G = 1.6 Film thickness 15 microns Film forming result good

Example 4 Resin Nylon 6 (commercially available copolymer) Density 1.16 Vicat Softening point 122 ° C. Annular slit diameter D = 200 mm Controlled cooling cylinder ratio G = 1.5 Film thickness 15 μm

(Comparative Example 1) A melt blow-up manufacturing method of a conventional unstretched film forming method as shown in FIG. 11 was used. Resin Polystyrene (the same resin as in Example 3,
(Same density and softening point) Annular slit diameter D = 200 mm (same as in Example 3) Degree of expansion 2.8 times of blow-up limit Film formation result Longitudinal tearing strong, changing from vertical tearing to lateral tearing Balance film cannot be manufactured (Comparative Example 2) A melt blow-up method of a conventional unstretched film forming method as shown in FIG. 11 is employed. Resin High-density polyethylene (the same resin, density and softening point as in Example 1) Annular slit diameter D = 200 mm (same as in Example 1) Expansion degree 4.5 times the blow-up limit Film-forming result The film was translucent without any directionality in both the vertical and horizontal directions and without crystal restrictions. (Comparative Example 3) A melt blow-up method of a conventional unstretched film forming method as shown in FIG. 11 is employed. Resin Nylon 6 (the same resin, density and softening point as in Example 4) Annular slit diameter D = 200 mm (Same as in Example 4) Expansion degree 1.6 times of blow-up limit Film formation result Longitudinal tearing, changing from horizontal tearing to vertical tearing Balance film cannot be manufactured

FIG. 8 shows Examples 1 to 4 and Comparative Example 1.
-For each sample of Comparative Example 3, thickness (mm), haze (%), tensile strength at break (gram / m ² ), tensile elongation at break (%), tear strength (R16), water vapor permeability at 40 ° C (Grams / m ² ) are compared in a table. FIG. 9 is a diagram comparing the film thickness in the vertical direction between Example 1 and Comparative Example 1, and FIG. 10 is a diagram comparing the film thickness in the horizontal direction between Example 1 and Comparative Example 1. Yes, the film of Example 1 is Comparative Example 1
It can be seen that the variation in the thickness in both the vertical and horizontal directions is smaller than that in FIG.

Finally, the manufacturing method of the third embodiment will be described in detail. A resin material obtained by adding a small amount of a modifier to a commercially available polystyrene resin and obtaining a blend for a biaxially stretched film,
It is extruded at 190 ° C. by a 0.8 mm lip of the annular slit 3 of the annular die 1 to form a molten tubular film 4.
The diameter G of the inlet of the control cooling cylinder 6 is set to 1.6 times the diameter D of the annular slit of the annular die 1, and the molten tubular film 4 is blown up.
Contact was initiated at ° C. Then, at the exit of the control cooling cylinder 6a, 1
It was rapidly cooled to 00 ° C. ± 1 ° C., and the working pressure of the pressure plate 8a was used at a converted value of 56 mmAq. The temperature of the heating cylinder 8a was set to 125 ° C., and hot air 40 was supplied from the tubular hot air outlet 16 at 126 ° C. at 0.37 cubic meters / minute. In addition, the stretch-guaranteed heater 36 is set to 125 ° C., and the extension-stretch is set to twice, so that the extension-stretch holding cylinder 1 is set.
9 was held. Then, the heating device 20 controlled the inlet temperature of the extension / stretch holding tube 19 to 130 ° C., and the cooling device 37 controlled the outlet temperature of the extension / stretch holding tube 19 to 60 ° C. to form a film.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a blown film manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the first embodiment.

FIG. 3 is a schematic vertical sectional view of a blown film manufacturing apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining the length relationship of components related to the blown film manufacturing apparatus.

FIG. 5 is a diagram for explaining a temperature range realized by a management cooling body and a temperature range mainly realized by hot air.

6 (A) is a longitudinal sectional view of a cooling management cylinder, FIG.
(B) and (C) are the longitudinal section partial enlarged views, respectively.

FIG. 7 is a vertical sectional view of a main part showing a configuration of a blown film manufacturing apparatus according to another embodiment of the present invention.

FIG. 8 is a table showing film characteristics of Examples and Comparative Examples according to the present invention.

FIG. 9 is a diagram comparing the thicknesses of the films according to Example 1 and Comparative Example 1 in the vertical direction.

FIG. 10 is a diagram comparing the thicknesses of the films according to Example 1 and Comparative Example 1 in the horizontal direction.

FIG. 11 is a schematic view showing a conventional apparatus for producing a blown film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Circular die, 3 ... Circular slit, 4 ... Molten tubular film, 6,6b ... Control cooling body, 6a ... Control cooling cylinder, 8 ...
Pressing body, 8a ... Pressing board, 8b ... Pressing cylinder, 9 ... Expansion and stretching air, 19 ... Extension and extension holding cylinder, 52 ... Expansion and extension air supply pipe, 54 ... Circular hot air blowing device, 62 ... Convex peripheral part , 6
4 ... Auxiliary air.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 7:00

Claims (15)

[Claims] An annular die having an annular slit (3).
A method for producing an inflation film in which a molten tubular film is extruded from (1) and air is blown into the molten tubular film through an annular die (1), wherein an outer periphery of the film is provided outside the tubular film extruded from the annular die (1). A control cooling body (6) having a peripheral wall abutting against the surface is provided, and the temperature of the film resin is controlled and cooled by the management cooling body (6), and the peripheral wall abuts on the inner peripheral surface of the film inside the tubular film. A pressurizing body (8) provided with a pressure member is provided, and the tubular film held by the control cooling body (6) is pressurized by the pressurizing body (8). And a lower part, and by heating the tubular film by expanding the tubular film by blowing hot air from the outer periphery to the tubular film that has come out to the upper side through the partition, Air for expansion and stretching (9)
Is blown into the inside of the tubular film. 2. An annular die having an annular slit (3).
A method for producing an inflation film in which a molten tubular film is extruded from (1) and air is blown into the molten tubular film through an annular die (1), wherein the inside of the tubular film extruded from the annular die (1) A control cooling body (6) having a peripheral wall abutting on the peripheral surface is provided, and the temperature of the film resin is controlled and cooled by the management cooling body (6), and the peripheral wall abuts on the outer peripheral surface of the film outside the tubular film. A pressurizing body (8) provided with a pressure member is provided, and the tubular film held by the control cooling body (6) is pressurized by the pressurizing body (8). And a lower part, and by heating the tubular film by expanding the tubular film by blowing hot air from the outer periphery to the tubular film that has come out to the upper side through the partition, Air for expansion and stretching (9)
Is blown into the inside of the tubular film. 3. An annular die having an annular slit (3).
A method for producing an inflation film in which a molten tubular film is extruded from (1) and air is blown into the molten tubular film through an annular die (1), wherein the inner peripheral surface or the outer periphery of the tubular film extruded from the annular die (1) The surface is brought into contact with the peripheral wall of the cooling body (6), and cooled while controlling the temperature of the film resin. The film opposite to the film surface that abuts the tubular film on the peripheral wall by the pressing body (8) By pressurizing from the surface side, the tubular film is partitioned into an upstream area and a downstream area at the boundary by the pressure, and hot air is blown from the outer periphery to the tubular film that has flowed downstream through the partition. Is heated so that the tubular film can be stretched and stretched, and air for stretching and stretching (9)
Is blown into the inside of the tubular film. 4. The method of manufacturing a blown film according to claim 1, wherein the tubular film expanded and stretched by the expansion and stretching air (9) is an expanded and stretched holding cylinder (19). A) a method for producing a blown film, the method comprising: 5. An annular die (1) for extruding a molten tubular film from an annular slit (3), and an expansion-stretching air supply passage for blowing expansion air through the annular die (1).
(52), a control cooling body (6) installed downstream of the annular die (1), holding the tubular film by the peripheral wall, and cooling while controlling the temperature thereof; and a control cooling body (6). A pressurizing body for pressing the film surface of the tubular film held on the peripheral wall of the control cooling body (6) from the side opposite to the peripheral wall
(8), an annular hot air blowing device (54) for blowing hot air from the outer periphery to the tubular film which has flowed out to the downstream side through the pressurization by the pressing body (8), and heating and expansion by the annular hot air blowing device (54) An extended stretch holding cylinder that holds an extended stretched tubular film that has been extended and stretched by blowing air for stretching (9).
(19) An apparatus for producing a blown film, comprising: 6. The apparatus for producing a blown film according to claim 5, wherein the control cooling body (6) is a control cooling cylinder (6a) provided outside a tubular film, and (8) An apparatus for producing a blown film, wherein the pressure plate (8a) is in contact with the inner peripheral surface of the tubular film. 7. The blown film manufacturing apparatus according to claim 5, wherein the control cooling body (6) is provided inside the tubular film, and the pressurizing body (8) contacts an outer peripheral surface of the tubular film. An inflation film manufacturing apparatus, characterized in that it is a pressurized cylinder (8b) in contact therewith. 8. The apparatus for producing a blown film according to claim 5, wherein said pressurizing member (8) is provided with a heating means. 9. The apparatus for manufacturing a blown film according to claim 5, wherein auxiliary air (64) can be supplied to the inside of the molten tubular film (4) from the annular die (1) to the control cooling body (6). An apparatus for producing a blown film, wherein an auxiliary air supply passage (53) is provided through the annular die (1). 10. The blown film manufacturing apparatus according to claim 5, wherein the diameter of the peripheral wall of the control cooling body (6) and the diameter of the pressurizing body (8) are in a range of 5 mm to 1 mm. An apparatus for producing a blown film, characterized in that a pressure difference is applied to the tubular film held on the peripheral wall of the control cooling body (6) by the difference in diameter. 11. The blown film manufacturing apparatus according to claim 9, wherein the molten tubular film (4).
The auxiliary air (64) supplied to the inside of the tube and the expansion / stretching air (9) for expanding / stretching the tubular film are separated by a controlled cooling body.
(6) The film is manufactured by applying pressure to the pressurizing body (8) to partition the film and shutting off the pressure so that one air pressure does not affect the other air pressure. Production equipment for blown film. 12. The method for producing a blown film according to claim 1, wherein the control cooling body (6) is provided with respect to the diameter of the annular slit (3) of the annular die (1). Is set in the range of 0.7 times to 2.3 times, and after the tubular film is brought into close contact with the control cooling body (6),
A method for producing an inflation film, comprising extending and stretching a tubular film. 13. The method for producing a blown film according to any one of claims 1 to 3, wherein a gradient is provided by making the diameter of the outlet and the diameter of the inlet of the control cooling body (6) different. A method for producing a blown film, wherein the tubular film has a take-up resistance. 14. A blown film manufacturing apparatus according to claim 5, wherein a raised convex portion (62) is provided on a peripheral wall of the management cooling body (6) where the tubular film abuts, and the convex peripheral portion (62) is provided. 62) An apparatus for manufacturing a blown film, wherein the take-up resistance of the tubular film is controlled according to 62). 15. The method for producing a blown film according to claim 4, wherein the extended stretch holding cylinder is provided.
A method of manufacturing a blown film, characterized by increasing the frictional resistance of the extended stretch holding cylinder (19) by making the diameter of the upstream side smaller than the diameter of the downstream side.