JPS6168223A - Air ring for producing tubular film - Google Patents

Abstract

PURPOSE:To make it possible to regulate the height of a frost line to an arbitrary desired position, by providing a ring shaped perforated cylinder on the inside lip of the slit of a cooling medium chamber or between the lip and a molten tube. CONSTITUTION:The molten tube 5 extruded from a ring shaped die 1 is preliminarily cooled in the space constituted by a ring shaped cooling medium chamber 2 and a ring shaped perforatedcylinder 4. A part of the cooling medium blown off toward the cylinder 4 from a lip 2 through a slit 3 passes through the cylinder 4 to flow to the space 6 and the cooling medium flowing outside said space 6 is met with the aforementioned cooling medium. When the speed of the medium passing through the gap 11 between the adjusting ring 9 provided to the upper part of a ring shaped cylinder 7 and the tube 5 is increased to perform final cooling, the tube 5 abruptly expands by Venturi effect to form a frost line. By this method, the height of the frost line is adjusted to a desired position to enable the stable manufacturing of a tubular film.

Description

[Detailed Description of the Invention] [Field of Application in the Ornamental Industry] The present invention relates to a bubble cooling ring made of tubular film made of thermoplastic resin, and more specifically, it relates to a ring for bubble cooling made of tubular film made of thermoplastic resin, and more specifically, it relates to a bubble cooling ring made of a tubular film made of thermoplastic resin, and more specifically, it relates to a bubble cooling ring made of a tubular film made of thermoplastic resin. In the production of thermoplastic resin films such as polyamide, polyethylene terephthalate, etc., when blowing out bubble cooling medium from a cooling ring, even if the blowing speed of the cooling medium increases, the bubbles may be crushed due to the influence of the pressure. Hunting and making friends, the desired 7
This invention relates to a cooling ring that can produce films with a zero-strain height.

[Conventional technology]

In the conventional manufacturing method of tubular film using the conventional single-stage cooling ring and the tube inflation method, the higher the film manufacturing speed and the higher the transparency of the film, the more the air blows out of the cooling ring. It is necessary to increase the blowing speed of the bubble cooling medium, which often causes the bubbles to be crushed under the pressure of the blowing cooling medium, thereby impairing the stable production of the film. The resin has a very low melt tension, and it has been extremely difficult to produce a film in a substantially satisfactory state.

As shown in FIG. 7, a cooling ring capable of solving the above-mentioned problem includes an annular cooling medium chamber 2 provided on an annular die 1 and an outer lip 2 constituting a slit 3 of the medium chamber.
a with a non-porous cylindrical body 4' connected thereto, or as shown in FIG. Examples include a so-called dual ring consisting of an annular cooling medium chamber 2 having an inner lip 2c and an inner lip 2b.

[Problem that the invention seeks to solve]

However, as shown in Fig. 7 and Fig. g8, these cooling rings have a space 6 consisting of a hollow top 5 and a non-porous cylindrical body 4', or a space 6 consisting of a hollow cylinder 5 and a non-porous cylinder 4', The 70-string design utilizes the so-called Venturi effect, which is a negative pressure generated in proportion to the flow rate of the cooling medium flowing through the space 6 formed by the outer lip 2a, to rapidly expand the bubble and prevent the bubble from shaking. It is extremely difficult to arbitrarily adjust the height of the bubble to a desired position, and from the above-mentioned principle of bubble stabilization, it naturally has the disadvantage that the bubble is not stable unless high-speed production is performed.

[Means and effects for solving the problem] The present inventors,
As a result of intensive research into a cooling ring that does not have the above-mentioned drawbacks, we have developed an annular cooling medium chamber and an annular porous tube disposed on the inner lip of the slit of the cooling medium chamber or between the lip and the melting tube. and a length-changeable structure having a ring disposed on the outside of the annular porous cylinder at the top = 1),
Furthermore, if an annular cylinder or a serpentine air ring is used that has air holes that allow air to be taken in substantially uniformly from the circumferential direction at arbitrary positions, the blowing speed of the cooling medium will be reduced when the cooling medium is blown out from the air ring. We have completed the present invention by discovering that even if the pressure increases, the tubes will not be crushed or hunted by the pressure, and it is possible to produce a film that has the desired height of 7 ct strings and does not block.

That is, the present invention provides a nine-annular cooling medium chamber provided with slits for blowing out the cooling medium, and an annular cooling medium chamber disposed on the inner lip of the slit of the cooling medium chamber or between the lip and the melting tube. Between the perforated cylinder and the annular perforated cylinder or tube which is disposed outside the annular perforated cylinder and is connected to the annular cooling medium chamber 1! It has a length equal to or longer than the annular porous cylinder, which has an adjustment ring on the top that can change li within an appropriate range, and the length can be changed arbitrarily. and an annular cylinder having air holes that allow air to be taken in substantially uniformly from the circumferential direction.

In the cooling medium chamber of the cooling ring of the present invention, the angle of the slit is preferably cf' to 6rf from the traveling direction of the tubular film to the central direction of the tubular film.

If it is less than σ, the film cooling efficiency will be poor, and if it is more than 6(f), the cooling medium will directly hit the tube, making stable film production difficult. The ninth position is 30°~6 [
f is preferred. The gap between the slits is usually 2 to 1011 II.
The degree is appropriate. Furthermore, the angle of the annular porous cylinder is from -3 cf to 60 degrees from the running direction of the Tuplar film to the center direction of the Tubular film, which means that the expansion of the Tuplar film is 0 for the bi-neck vibro-type.
This is because a low-neck low (or high) blow film with a low neck strength of 3 cf' is preferable for stable production of 131f-cl) film.

The length of the annular porous cylinder is 0.5 to 1.5D (here, D
If the inner diameter of the slit is less than 0.5D, the pressure of the blown out high-speed cooling medium cannot be sufficiently reduced, and if it is more than 1.5D, the cooling efficiency will deteriorate. Examples of the structure of the annular porous cylinder include a sintered body, punched metal, and a mesh body. From the viewpoint of stable production of the film and cooling effect, the perforated cylinder has holes arranged at substantially equal intervals and preferably has a porosity in the range of 15 to 60 inches. The holes arranged at substantially equal intervals may have any structure, regardless of their shape, as long as they can blow out the gaseous cooling medium uniformly in the circumferential direction of the porous cylinder.

Here, the porosity is the ratio of the area of the aperture to the total area of the annular porous tube, which is based on the height t of the annular porous tube located above the upper end of the inner lip of the slit of the annular coolant chamber.

Note that the porosity of the sintered body is defined as the porosity.

If the porous tube is placed on the inner lip of the slit, it is screwed or fitted into the lip, and if it is placed between the lip and the melting tube, the ring is attached. For those in contact with the lip or in the space formed by the lip and the melting tube, examples include screwing or fitting into the upper surface of the annular die.
However, the present invention is not limited to this, and it may be installed in such a manner that the pressure of the cooling medium blown out from the slits in the cooling medium chamber can be reduced.

Further, in the case where a joint with the cooling ring is provided on the annular die for the purpose of heat insulation and alignment, the annular porous tube may be attached by screwing or fitting into the joint.

The structure of the adjustment ring provided on the upper part of the annular cylinder connected to the annular cooling medium chamber may be any structure as long as the gap between the annular porous cylinder or tube can be changed within an appropriate range. Generally, one having an aperture mechanism is practical.

In addition, structures in which the length of the annular cylinder can be arbitrarily changed include those in which the contact part is a flexible bellows mechanism, or in which there are multiple sleeves of different diameters, each of which can be adjusted according to the feldspar of the cylinder. Examples include, but are not limited to, those that have a mechanism that allows them to be pulled out.

The part where the length of the annular cylinder can be arbitrarily changed may extend over the entire length of the annular cylinder or may be partial. O Air can be taken in substantially evenly from the circumferential direction to any position of the annular cylinder. The air hole structure is formed by perforating the annular tube, and the shape of the hole may be any shape, such as a round fox rectangle, as long as it can take in air substantially evenly from the circumferential direction, Further, it may be possible to adjust the opening degree of the hole.

Air is generally used as the cooling medium, but mist may also be used to increase the cooling capacity.

One embodiment of the invention is shown in FIG.

FIG. 1 is a cross-sectional view when the tube is expanded at low-neck high blow. The d-melt tube 5 extruded from the annular die 1 is precooled by a space 6 consisting of a yield-shaped cooling medium chamber 2 and an annular porous cylinder 4. Ru.

The cooling medium passes through the slit 3t consisting of the inner lip 2b and the outer lip 2a and is blown out toward the annular porous tube 4, and a part of the coolant passes through the annular porous tube 4t and is formed into the annular porous tube 4 and the melting tube 5. A part of the flow flows through the outer space 6t of the annular porous cylinder 4.

The cooling medium flowing outside 111J of the annular porous tube 4 then merges with the cooling medium that has passed through the annular porous tube 4 in the space 10 consisting of the annular porous holes f1M4 and the li-shaped housing tube 7, forming a turbulent flow. The melting tube 5t'' is further cooled.

An adjustment ring 9 provided at the top of the annular tube 7 is fixed at any position in the Tuegler film running direction by an adjustment ring support rod 8, and forms a gap 11 with the melting tube 5 to adjust the flow rate of the cooling medium. At the same time, the frost line 12 is formed while the tube is rapidly expanded by the Venturi effect.

FIGS. 2 and 3 are cross-sectional views of an embodiment of the present invention showing how the annular porous cylinder is attached, which is different from that shown in FIG. 1.

FIG. 2 shows a Q'ra-shaped simple porous annular coolant chamber 2 in which it is placed in contact with the inner lip 2b and is fitted onto the top surface of the annular die 1, and FIG.
An annular porous cylinder 4 is arranged in a space formed by an inner lip 2b provided in an annular cooling medium chamber 2 and a melting tip 5,
It is attached to the top surface of an annular die 1 with a screw.

Fig. 4 shows the structure of the A4') ring 9, which is configured to move forward and backward toward the center by rotating the rotation plate 9b. It has a wringer 4@ consisting of blades 9C.

FIG. 5 is a perspective view of one embodiment of the annular porous tube 4 constituting the cooling ring of the present invention, and its structure is made of punched metal.

FIG. 6 is a cross-sectional view of one embodiment of the annular tube 7 constituting the cooling ring of the present invention, the material of which is aluminum for the ring portion and the tube portion having air holes, and the rubber-coated portion for the flexible chamfer. It's cloth.

The air passes through the air hole 7dz, which is also perforated with γdK, and rises along the shielding cylinder 7d2 provided in the cylinder part 7d.

The shielding cylinder 7d2 prevents the cooling medium rising inside the annular cylinder 7 from flowing out from the air hole 7dl, and also prevents the cooling medium flow from flowing in the space formed by the cylinder part 7d and the shielding cylinder 7d2. This effect promotes the generation of negative pressure.

〔Example〕

Next, using the cooling ring of the present invention, a copolymer of ethylene and 1-octene is used. -(v-technique 1-ag/10m1n density 0.9209/7IL3, product name Dowr, gx 2
045) The stability of film production and the high 70-strain performance when manufacturing a film, using a conventional single-stage cooling ring, and when manufacturing a film T-S by disposing a non-porous cylinder on this ring. Table 1 shows a comparison of the adjustment ranges of height.

(Margins below) Table 1 The film manufacturing conditions are as follows: 50φ extruder with 150 blades in diameter;
Attach a spiral die with a die gap of 1 mm,
Extrude! 35kl? /hour, resin temperature 210℃, blow ratio 2
．． 0, film thickness is 35μ. The dimensions of the cooling ring according to the present invention used in this practical example are shown in Table 2.

Table 2 [Effects] The annular porous tube placed on the inner lip of the slit in the cooling medium chamber or between the lip and the bath melting tube reduces the pressure of the blown out high-speed cooling medium and cools it. It not only reduces the impact of the medium on the tube and prevents the tube 7' from being crushed 9 or hunting 11;
To improve the cooling efficiency by creating an extremely complicated flow of a cooling medium in a space composed of an annular porous cylinder and a tube to disturb the heat flow flowing along the tube; Since the venturi effect that causes the tube to expand rapidly does not occur in the space and at the exit of the porous tube, the height of the crossline can be adjusted to any desired position to easily change the deformation ratio of the film. It becomes possible.

The annular tube disposed outside the annular porous tube and connected to the annular cooling medium chamber has an adjustment ring at the top that can change the gap between the annular holes or with the tube within an appropriate range. Therefore, the gap formed between the annular porous cylinder and the adjustment ring or the tube and the adjustment ring can be changed and adjusted within an appropriate range, so that the flow rate of the cooling medium can be increased and the tube can be adjusted in the vicinity of the gap. This creates a Venturi effect that causes rapid expansion, and the tube is cooled completely efficiently.

In addition, since the annular cylinder has a structure that allows its length to be changed arbitrarily, the synergistic effect with the annular pores allows the height of the frost line to be adjusted to any desired position and the film to be deformed. Since the ratio can be easily changed, the mechanical properties such as tensile strength and tear strength of the film can be balanced vertically and horizontally extremely well even in high-speed production.

Furthermore, by providing air holes at arbitrary positions of the annular cylinder that can take in air substantially uniformly from the circumferential direction, low-temperature outside air is introduced into the annular cylinder, so that the bath melting tube can be heated inside the annular cylinder. The cooling medium, which absorbs heat from the air and accumulates heat to reach a high temperature, is also taken in through the air hole mentioned above and is connected to the outside air.
Since the temperature of the molten tube is lowered by IL exchange or heat exchange, the position of the cross line is correspondingly lowered, and the cooling zone from the frost line to the nip roll becomes substantially longer. The degree of curling of the tubular film that is folded and wound with the nip rolls will be reduced.

[Brief explanation of drawings]

Figure 1 shows one version of the cooling ring according to the present invention! sectional view of
FIGS. 2 and 6 are cross-sectional views of an embodiment of the present invention showing how the annular holes are attached, which is different from that shown in FIG. 1. FIG. 4 is a plan view of an embodiment of the adjusting ring used in the cooling ring of the present invention, FIG. 5 is a perspective view of an embodiment of the adjustment ring used between the annular holes used in the cooling ring of the present invention, and FIG. 6 is a plan view of an embodiment of the adjusting ring used in the cooling ring of the present invention. 7 and 8, which are cross-sectional views of one embodiment of the annular cylinder used, are cross-sectional views of a conventional cooling ring in use. In the figure, 1 is an annular die, 2 is an annular cooling medium chamber, 2a is an outer lip, 2b is an inner lip, 2C is an intermediate lip, 3,
3' is a slit, 4 is an annular hole, 4' is a cylinder, 5 is a melting tube, 6 is a space, 7 is an annular cylinder, 7d1 is an air hole, 7d2 is a shielding cylinder, 8 is an adjustment ring support rod, 9 is a In the adjustment ring, 10 is a space, 11 is a gap, and 12 is a frost line. Patent applicant: Asahi Kasei Kogyo Co., Ltd. Figure 1 Figure 2 Cause Figure 3 Figure 4 Figure 5 Figure 6 a

Claims (1)

[Claims] 1. An annular cooling medium chamber provided with a slit for blowing out a cooling medium, and an annular cooling medium disposed on the inner lip of the slit of the cooling medium chamber or between the lip and the melting tube. An adjustment ring is provided on the upper part of the porous tube and the annular porous tube is arranged outside the annular porous tube and connected to the annular cooling medium chamber, and can change the gap between the annular porous tube or the tube within an appropriate range. , has a length equal to or longer than the annular porous cylinder, and has a structure that allows the length to be changed arbitrarily, and further allows air to be taken in substantially uniformly from the circumferential direction at any position. The air ring 2 for manufacturing tubular film is characterized in that it is composed of an annular tube having a structure having holes, and the annular porous tube is made up of holes arranged at substantially equal intervals, and the porosity thereof is The air ring for manufacturing tubular film according to claim 1, characterized in that the ratio is 15 to 60%.