JP2009269382A - Thickness deviation adjusting air ring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thickness deviation adjusting air ring that optimally controls a cooling air temperature, without interrupting a cooling air flow, in the circumferential direction under passage of time, thereby producing a synthetic resin film excellent in thickness deviation, physical properties, etc., in an inflation film production apparatus. <P>SOLUTION: A number of arc plates 12 are set in ring form at a prescribed gap to cross the cooling air flow at right angle inside a cooling air channel of an air ring 4, in parallel with uniting each arc plate 12 in ring form by filling a heat insulator 12a to the gaps and electrical heating rods 9 for thickness deviation adjustment are embedded to each of the arc plates 12, wherein the air ring is mounted on a die 2 of an inflation film production apparatus 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is placed on a die of an inflation film manufacturing apparatus for forming (manufacturing) a synthetic resin film, and cooling air is blown around the extruded synthetic resin tube to cool and solidify, thereby forming the synthetic resin film. In particular, the present invention relates to a thickness adjustment type air ring that partially controls the temperature of the cooling air in the circumferential direction to adjust the thickness deviation (thickness variation) of the synthetic resin film.

  In blown film production equipment, when a synthetic resin film is formed by cooling and solidifying a molten synthetic resin tube extruded from a die slit with an air ring, a partial temperature difference is caused in the circumferential direction against the cooling air. Thus, adjusting the uneven thickness of the synthetic resin film has been conventionally performed.

As a first example of this type of air ring, for example, as shown in FIG. 4 (see Patent Document 1 and Patent Document 2), the cooling air flow path in the air ring 100 is subdivided into a fan shape by a large number of plate-like bodies 101. Extruded melt synthesis by heating the plate-like body 101 itself (in the case of Patent Document 2) or by heating with the electric heating rod 102 provided between adjacent plate-like bodies 101 (in the case of Patent Document 1) The cooling air directed to the resin tube can be partially temperature controlled in the circumferential direction. In FIG. 4, reference numeral 103 denotes a hose port through which cooling air from a blower (not shown) is introduced through a hose connected to the hose port 103. In the illustrated example, four hose openings 103 are formed at predetermined intervals in the circumferential direction.
US Pat. No. 5,288,219 Japanese Patent Publication No. 7-71817

In addition, as a second example of this type of air ring, for example, as shown in FIG. 5 (see Patent Document 3), heating by an electric heating rod 202 embedded in a ring-shaped baffle plate 201 in the air ring 200 is performed. The cooling air directed to the extruded molten synthetic resin tube can be partially temperature controlled in the circumferential direction.
JP 2004-330537 A

  However, in the air ring 100 having the above-described configuration of the first example, the flow of the cooling air divided by the plate-like body 101, the electric rod 102, or the like (refer to the streamline indicated by the arrow in FIG. 4). There is a problem that the turbulent state is disturbed and adversely affects the uneven thickness and physical properties of the synthetic resin film which depends on the state of the cooling air flow.

  Further, in the air ring 200 having the configuration of the second example described above, there is no problem that the flow of the cooling air is in a turbulent state as in the first example. However, in order to heat the baffle plate 201 with the electric heating rod 202 and indirectly heat the cooling air with the heat, the material of the baffle plate 201 needs to be a heat conductor. The heat of the electric heating rod 202 at a given position is transmitted to a circumferential portion that does not require heating of the baffle plate 201 as time passes, and a partial temperature in the circumferential direction of the baffle plate 201 is used for the purpose. You can no longer control the street. Therefore, since the partial temperature of the cooling air in the circumferential direction cannot be optimally controlled, there is a problem that the uneven thickness of the synthetic resin film cannot be adjusted accurately.

  Therefore, the present invention can control the partial temperature in the circumferential direction of the cooling air accurately and optimally according to the purpose without dividing the flow of the cooling air and with the passage of time. It is an object of the present invention to provide a thickness adjustment type air ring capable of stably producing a synthetic resin film excellent in physical properties and the like even for a long time operation.

  In order to solve the above problems, a synthetic resin film is placed on a die of an inflation film manufacturing apparatus for forming a synthetic resin film, and cooled and solidified by blowing cooling air around the extruded synthetic resin tube. In forming an uneven thickness adjustment type air ring that adjusts the uneven thickness of the synthetic resin film by partially controlling the temperature of the cooling air in the circumferential direction when molding, the cooling air flows into the cooling air flow path of the air ring. A large number of arc plates are annularly arranged with a predetermined gap so as to be orthogonal to the flow, and at the same time, the gap is filled with a heat insulating material so that the arc plates are integrated into a ring shape. A heating element for adjusting uneven thickness is embedded in the plate.

  According to the present invention, a large number of arc plates are integrated in a ring shape via a heat insulating material, and there is no occurrence of turbulence in the flow of cooling air due to dividing the flow of cooling air, In addition, since heat conduction to the adjacent arc plates is prevented by the heat insulating material filling the gaps between the arc plates, each arc plate can be accurately controlled at the required temperature, and the temperature of the cooling air can be controlled in the circumferential direction. Can be partially controlled optimally, and a synthetic resin film excellent in uneven thickness and physical properties can be stably produced even during long-time operation.

  Hereinafter, an embodiment of an uneven thickness adjusting type air ring according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view around a thickness adjusting type air ring according to the present invention used in the inflation film manufacturing apparatus shown in FIG. 3, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 3, in the inflation film manufacturing apparatus 1, the molten synthetic resin 3 a supplied to the die 2 from an extruder (not shown) is extruded as a molten synthetic resin tube 3 from the die slit 2 a (see FIG. 1) and flows. Is stretched thinly in both the circumferential direction and the circumferential direction, and is cooled by cooling air 5 from a blower (not shown) blown out from the air rig 4 to become a tube-shaped synthetic resin film 3b, which is taken up by a pinch roll 6 and wound up (not shown) Rolled up by the machine. At this time, air of a predetermined pressure is sealed inside the melted synthetic resin tube 3 (tube-shaped synthetic resin film 3b).

  The upstream portion of the pinch roll 6 is provided with an electrostatic thickness sensor 7 that measures the thickness of the tube-shaped synthetic resin film 3b while reversing 360 °, and the detection signal is composed of a microcomputer or the like. Input to the control unit 8.

  Based on the thickness deviation information of the synthetic resin film 3b obtained by the detection signal from the thickness sensor 7, the control unit 8 is a required electric heating rod (heating element) 9 (see FIG. 1 and FIG. 2), the temperature is partially controlled in the circumferential direction with respect to the cooling air flowing in the air ring 4, and the uneven thickness of the synthetic resin film 3b is as small and uniform as possible. It tries to become.

  As shown in FIGS. 1 and 2, the air ring 4 described above is composed of a ring-shaped housing having a concave inner peripheral portion, and a ring-shaped outlet 4 a formed in the inner peripheral portion is a ring in the die 2. It is fixed on the die 2 by an appropriate means so as to be concentric with the shaped die slit 2a.

  The outer peripheral side inside the air ring 4 is defined by the ring-shaped perforated rectifying plate 10 into an outer cooling air passage 4b and an inner cooling air passage 4c. Four hose ports 11 are formed at equal intervals in the outer cooling air flow path 4b in the circumferential direction, and cooling air 5 from a blower (not shown) is introduced through the hoses connected to the hose ports 11. It has become.

  In the inner cooling air flow path 4c, a large number of arc plates 12 made of aluminum alloy or the like having a high thermal conductivity are provided in a predetermined manner so as to be orthogonal to the flow of the cooling air (see arrows in FIGS. 1 and 2). The gap is annularly arranged, and the gap is filled with a heat insulating material 12a bonded to the arc plate 12 with a heat-resistant adhesive or the like, and a large number of the arc plates 12 are integrated in a ring shape, The aforementioned electric heating rod 9 as a heating element for adjusting the thickness deviation is embedded in each of the large number of arc plates 12. A ring-shaped heat insulating plate 14 is disposed between the arc plate 12 and the housing. The heat insulating material 12a and the heat insulating plate 14 are preferably made of a material having a thermal conductivity of 10 W / mk or less.

  Due to this configuration, the cooling air 5 from the blower is branched into four hoses and introduced into the outer cooling air flow path 4 b of the air ring 4 from the hose port 11. From here, the baffle plate 13 and the circular arc plate 12 in the inner cooling air flow passage 4c meander up and down as shown by arrows in FIG. Then, it passes through the blowout port 4a and is blown to the molten synthetic resin tube 3.

  Therefore, the cooling air rectified by the perforated flow straightening plate 10 or the like is melted while being in a uniform flow state without being divided by the circular arc plate 12 and the heat insulating material 12a formed integrally in the ring shape. The synthetic resin tube 3 is cooled and solidified.

  Furthermore, the heat of the electric heating rod 9 is prevented from being transmitted to other than the required location by the heat insulating material 12a filling the gaps between the arc plates 12 and the heat insulating plate 14 between the arc plates 12 and the housing. Therefore, the temperature of the cooling air can be partially and accurately controlled in the circumferential direction corresponding to the thickness of the molten synthetic resin tube 3 (tube-shaped synthetic resin film 3b) even in continuous operation.

  Here, the solidified portion of the melted synthetic resin tube 3 pushed out from the die slit 2a is not stretched and is not further thinned. However, the unsolidified portion is stretched and thinned until solidified. Therefore, if the temperature of the cooling air corresponding to the thick portion in the circumferential direction of the tube-shaped synthetic resin film 3b is increased, the cooling / solidification of the portion of the molten synthetic resin tube 3 is delayed and thinned. The meat can be controlled.

  That is, based on the thickness deviation information of the thickness sensor 7, the electric heating rod 9 corresponding to the thick portion of the tube-shaped synthetic resin film 3b is energized and controlled by the control unit 8 so as to increase the temperature of the cooling air. That portion of the resin tube 3 is thinned to form a uniform tube-shaped synthetic resin film 3b with a small uneven thickness.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the temperature of the cooling air may be lowered using a Peltier element or the like instead of the heating rod 9. Further, the arc plate 12 in which the electric heating rod 9 is embedded may be arranged in multiple stages.

[Effect of the embodiment]
According to this embodiment, since a large number of arc plates 12 are integrated in a ring shape with the heat insulating material 13 filled in the gaps between the arc plates 12, a uniform flow without division of the cooling air can be obtained. Due to the heat insulating effect of the material 13, partial temperature control in the circumferential direction of the cooling air can be maintained in an optimum state even during long-time operation.

  Using LLDPE with an MFR of 1 as the raw material, tube thickness of 830 mm, thickness of 80 μm, and continuous operation for 30 hours under the manufacturing conditions of 14 m / min, uneven thickness of ± 5.3% to ± 5.8% (based on average thickness) As a result, it was possible to form a synthetic resin film.

It is sectional drawing around the thickness adjustment type | mold air ring which concerns on embodiment of this invention. Similarly, it is the sectional view on the AA line of FIG. It is a schematic block diagram of an inflation film manufacturing apparatus. It is a plane sectional view of the conventional uneven thickness adjustment type air ring. Similarly, it is a plane sectional view of a conventional uneven thickness adjustment type air ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inflation film manufacturing apparatus 2 Die 2a Die slit 3 Molten synthetic resin tube 3a Molten synthetic resin 3b Synthetic resin film 4 Air ring 4a Outlet 4b Outer cooling air flow path 4c Inner cooling air flow path 5 Cooling air 6 Pinch roll 8 Control unit 9 Electricity Heating rod 10 Perforated current plate 11 Hose port 12 Arc plate 12a Heat insulating material 13 Baffle plate 14 Heat insulating plate

Claims (1)

When the synthetic resin film is formed on the die of an inflation film manufacturing apparatus for forming the synthetic resin film, the cooling air is blown around the extruded synthetic resin tube to cool and solidify the molded resin film. In the uneven thickness adjustment type air ring that partially controls the temperature in the circumferential direction to adjust the uneven thickness of the synthetic resin film,
A large number of arc plates are annularly arranged with a predetermined gap in the cooling air flow path of the air ring so as to be orthogonal to the flow of the cooling air. Is integrated into a ring shape, and a heating element for adjusting the thickness deviation is embedded in each arc plate.

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