JPS5857923A - Air cooling ring for forming tubular film - Google Patents

Abstract

PURPOSE:To form an excellent tubular film by a method wherein a charged air cooling section, a cooled air compressing section, a cooled air discharging section are installed from the outer periphery of air cooling rings toward the center and charged air is cooled and rectified by repetition of adiabatic compression and expansion. CONSTITUTION:While refrigerant 6 is charged from an inlet 3 and is let into the internal part of a double walls of a periphery wall 1 and a refrigerant tank 7, air is charged from an inlet 15 into the 1st cooling room 11 of the charged air cooling section A. The air flows into a cooled air passage room 12 through communicating holes 14 of the refrigerant tank 7 and into the 2nd cooling room 13. At this time the refrigerant tank 7 having many communicating holes 14 is provided on the charged air cooling section A, the peripheral wall 1 also has a cooling function, therefore, cooling effect is extremely high by heat transmission and adiabatic expansion. Rectifying effect is constituted to be given by many communicating holes 14 and so rectified and cooled air is blown against molten resin material discharged from a die.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air cooling ring for forming tubular films.

During tubular film molding, particularly blown film molding, an air cooling ring is used to continuously blow cooling air onto the outer peripheral surface of a molten resin material extruded from an extrusion die. In this air cooling ring for blown film molding, excellent physical properties are determined by how low the temperature of all the discharged air is cooled and how the discharged air is rectified and blown onto the outer peripheral surface of the resin material. Inflated film 't4 [This is extremely important for forming with good properties, and many improvements have been made over the past.

For example, as a tool to improve the rectification function,
No. 14948 discloses an air cooling ring in which an air introduction passage is provided in the tangential direction and a rectifying pipe is provided inside the ring. However, in such an air cooling ring, although the Ii flow effect of the discharged air was observed, the cooling effect was extremely low.

In addition, as a means to improve the cooling effect,
No. 4147, by direct contact with the refrigerant! It is known that air is cooled. However, if such an air cooling ring is used for high-speed molding, the flow rate of air will be large and the flow velocity will be high in high-speed molding, so water droplets, which are the refrigerant, will be entrained in the discharged air. As a result, the molded film had a defect such as spots and spots. Furthermore, the gas-liquid contact filler in the air cooling ring is contaminated and must be replaced, resulting in low workability.

The object of the present invention is to produce a tubular film which has both a remarkable rectifying effect and a cooling effect, and therefore has extremely excellent physical properties, especially an air cooling ring for forming a tubular film that can be used to form the entire blown film and has great applicability to high-speed forming. It's on the side.

In the present invention, an inlet air cooling section, a cooling air pressure moving section, and a cooling air discharge section are provided in this order from the ring outer circumferential side toward the ring center, and the inlet air cooling section includes a plurality of inlet air cooling sections. A cooling 1s paddle is provided which is divided into chambers and has a large number of communication holes that communicate the plurality of chambers with each other, and the air introduced into the introduced air cooling section is fed through all the communication holes to repeat adiabatic compression and adiabatic expansion. The purpose of cooling and rectifying the introduced air is to achieve the above object by dividing the air into separate chambers and then passing the air into each chamber.Hereafter, embodiments of the present invention will be explained based on all the drawings.

FIGS. 1 and 2 show a plan view and a sectional view of an embodiment of the present invention taken along a half plane surrounding the central axis.

In these figures, each of the air cooling rings is formed in an annular shape, and cooling air in the introduced air cooling section A1 is sequentially arranged from the outer circumference of the ring, that is, the left side in the figure, toward the center of the ring, that is, the right side in the figure. It is composed of a compression section B1 and a cooling air discharge section C.

The peripheral wall 1 of the introduced air cooling section A has a double-walled hollow shape over its entire area, into which the refrigerant flows from the inlet 3 of the lower wall 2 and the refrigerant outlet 5 of the upper wall 4. The refrigerant 6 to be discharged is full. This refrigerant 6 is a commonly used refrigerant such as cold water or chlorofluorocarbon gas.

A refrigerant tank 7 is located approximately at the center of the introduced air cooling section A.
is provided. This refrigerant tank γ is formed in a hollow shape similar to the peripheral wall 1, and is connected through an upper partition wall 8 and a first and second lower partition wall 9 and 10, each of which is formed in a hollow shape to allow the refrigerant 6 to pass therethrough. The refrigerant 6 is in communication with the hollow part of the peripheral wall 1, and the refrigerant 6 flowing in from the refrigerant inlet 3 flows into the refrigerant tank 7.

The introduced air cooling section A includes a refrigerant tank T and the partition wall 8.9.
10 from the left side to the right side in FIG.
1, a cooling air passage chamber 12, and a second cooling chamber 13, and these chambers 11, 12, and 13 are communicated with each other through a number of communication holes 14 provided in the refrigerant tank 7.

The plurality of communication holes 14 are provided so as to be located on a virtual plane including the ring center axis of the air cooling ring, and are arranged so as to be located on a virtual plane including the ring center axis of the air cooling ring, and are arranged to allow air to be introduced through the air inlet 15 provided in the first cooling chamber 11 into the air cooling section. The air introduced into A flows from the first cooling chamber 11 to the cooling air passage chamber 12 and from the cooling air passage chamber 12 to the second cooling chamber 13, thereby being cooled while repeating adiabatic compression and adiabatic expansion. It is configured to be rectified as well as to be rectified.

The size and number of the communication holes 140 are appropriately selected depending on the overall size of the air cooling ring, the size of the die to be applied, the necessary cooling air blowing noise, etc.
, the cooling air passage chamber 12 and the second cooling chamber 13 are provided with condensed water drain ports 16 and 1 at predetermined positions on the lower wall 2 side, respectively.
7, and 18 are provided, each room 11, 12.1
The structure is such that even if condensed water is present in the tank, the condensed water is quickly drained and removed. In addition, there is a drain port 16.17.18 at the bottom of each chamber 11.12.13 so that condensed water can easily collect in the drain port 16.17.18.
In particular, at the drain port 18 of the second cooling chamber 13, the recess is formed by the second lower partition wall 10 and the inner wall 24 of the purification air compression section B. , and the drain port 18 may be located deep within this recess.

The cooling air flow path formed by the inner wall 21 of the self-cooling air compression section B is narrower on the ring center side than on the ring outer circumference side of the air cooling ring, and the cold air is narrower on the ring center side than on the ring outer circumference side of the air cooling ring. It is constructed so that it is compressed as it goes toward the end, and the pressure necessary for discharge is accumulated.

Further toward the center of the cooling air compression section B, a cooling air discharge section C is formed integrally with the compression section B. This cooling air discharge part C is connected to two of the first slit 31 and the second slit 32 provided on the outer peripheral side of the first slit 31.
It is a so-called double slit type having two slits, the first and Wc2 slits 31 and 32.
The cooling air rectified from #2 is discharged upward in FIG. 2 at a predetermined angle. In addition,
The cooling air discharge part C is not limited to a so-called double slit type, but may be a single slit type.

Next, the effect of this example will be explained. This example is applicable to highly concentrated, low-density polyethylene, polypropylene, ethylene-α-olefin copolymer,
Tubular molding of polyvinyl chloride, polyvinylidene chloride, polystyrene, etc. is used, but extrusion molding of thermoplastic resin pipes, etc. may also be used.

Refrigerant 6' from refrigerant inlet 3? ! : Air is introduced from the air inlet 15 while flowing the cold 1s6 inside the double wall of the peripheral wall 1 and the refrigerant tank 7 into the first cooling chamber 1 of the air cooling section A.
1. Then, the introduced air passes through the communication hole 14 of the refrigerant tank 7 to the cooling air passage chamber 12, and then to the passage chamber 1.
2 to @2 cooling chamber 13. At this time, when the introduced air passes through the communication hole 14, the introduced air is cooled by heat transfer and passes through the communication hole 14 to the passage chamber 12.
The adiabatic expansion e when flowing into the second cooling chamber 13 results in rough cooling, and since the communication hole 14 is provided so as to be located on a virtual plane including the ring center axis, the first cooling chamber 11 No matter from which direction the air is introduced, all the cooling air flowing through the second cooling chamber 13 is rectified and flows from the outer circumferential side of the ring toward the center of the ring.

In addition, the peripheral wall 1 of the introduced air cooling section A has a double wall structure over the entire area VC, and the refrigerant 6 is flowed through the inside of the double wall, and the introduced air reaches all the chambers of the introduced air cooling section A. That is, all of the first cooling chamber 11, cooling air passage chamber 12, and second cooling chamber 13 are also cooled.

The cooling air that has been extremely cooled and rectified in the introduced air cooling section A is once compressed in the cooling air compression section B, and then discharged into circular tube shapes from the slits 31 and 32 of the cooling air discharge section.

This embodiment has the following effects.

The introduction air cooling section A is provided with a refrigerant tank 1 having a large number of communication holes 14, and the peripheral wall 1 is also configured to have a cooling function, so that heat transfer and adiabatic expansion in the introduction air cooling section A are prevented. This has the effect that the cooling effect of the introduced air is extremely high. Moreover, the plurality of communication holes 1
4, it is configured to have a rectifying effect, and together with the cooling effect described above, extremely rectified and cooled air is continuously blown onto the outer peripheral surface of the molten resin material discharged from the die. I can go. Therefore, it has become possible to form a blown film that has no wrinkles or sagging, has uniform and excellent physical properties, and has a uniform thickness.

Furthermore, in the molding of transparent films, particularly in the molding of films of ethylene-α-olefin copolymers, etc., there is an effect that the transparency of the film can be significantly improved.

Moreover, since it has excellent rectification effect and cooling effect, it has the effect that it can be particularly applied to high-speed molding.

t1.During cooling, the introduced air and refrigerant are not brought into direct contact.9th, there is no risk of the refrigerant being entrained in the cooling air discharged through the slits 31 and 32 and having an adverse effect on the film. .

Furthermore, even if condensed water is generated in the introduced air cooling section A, the condensed water is quickly discharged through the drain port 16.17゜18, so that the condensed water becomes sludge).
There is no fear that the air will be entrained in the cooling air that is discharged further.

In the above-described embodiment, the peripheral wall 1 has a double wall structure over its entire area, and the refrigerant 6 is flowed inside the double wall to have a cooling function. The entire area of the peripheral wall 1 does not necessarily have to have a double wall structure, but depending on the required cooling capacity, for example, only the lower wall 2 or only the upper wall 4 may have a double wall structure. The circumferential wall 1 may have a double-walled structure only in one area, or the peripheral wall 1 may not have a double-walled structure at all.

Furthermore, the air inlet 15 may be attached at any angle in the first cooling chamber 11 at any desired location.

Furthermore, although only one refrigerant tank 7 is provided, there is also a second refrigerant tank 7 depending on the customer of the extruder to which it is applied. A plurality of refrigerant tanks such as a sixth refrigerant tank may be provided, and the inside of the introduced air cooling section A may be further divided into a large number of chambers.

Further, although the drain ports 16, 17, and 18 are not necessarily required, it is extremely convenient to remove condensed water if all or part of the drain ports 16, 17, and 18 are provided.

As described above, according to the present invention, both the rectifying effect and the cooling effect are excellent, and as a result, a tubular film with extremely excellent physical properties can be formed, and the tube two-film forming method is highly applicable to high-speed forming. can provide air cooling rings for use.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of an embodiment of the air cooling ring for tubular film molding according to the present invention, and FIG.
It is a sectional view taken along the line -■. A...Introduction air cooling section, B...Cooling air compression section,
C... Cooling air discharge part, 1... Peripheral wall, 6.
... Refrigerant, 7... Refrigerant tank, 11... First cooling chamber, 12° cooling air passage chamber, 13... Second cooling chamber, 14... Communication hole, 16, 17. 18.・
・Drain port. Agent: Patent Attorney Minoru Kinoshita Third Procedural Amendment: December 3, 1980 Haruki Shimada, Commissioner of the Japan Patent Office] Display of the case: 1982 Patent Application No. 157776 3, Person making the amendment Relationship with the case: Patent issuer 4. Agent 6: No increase in the number of inventions due to amendment 1) Change "molten resin material" in line 6 of page 2 of the specification to "molten resin material." (2) Add "melting" to the age of "resin piece" on page 2, line 11 of the specification. (3) "Tubular molding" in the 8th negative 9th line of the specification has been changed to "inflation molding". that's all

Claims (1)

[Scope of Claims] (1) The introduced air cooling section, the cooling air discharge section, and the cooling air discharge section are provided in this order from the outer ring side toward the center of the ring, and the introduced total air cooling J4I is The refrigerant tank is divided into a plurality of chambers, and the plurality of chambers are provided in the refrigerant tank and have a 7'C communication hole. An air cooling ring for tubular film molding, characterized by being connected to each other. (2) %1ff - In claim 1, all features include the fact that the entire or part of the peripheral wall of the stl air cooling section is formed by a double wall forming a refrigerant circulation section. Air cooling ring for tubular film molding. (8) The air cooling ring for forming a tubular film according to claim 1 or 2, wherein the introduced air cooling section is provided with a condensed water outlet.