JP2000158516A - Lip clearance regulator for t-die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately finely regulate a thickness of a resin film in a short time by expanding or contracting an expansion bolt by heating or cooling in a lengthwise direction, moving a pushing and pulling piece based on the expansion or contraction, and regulating a lip interval. SOLUTION: A lip clearance regulator B is newly added to a lip clearance regulator B. Its expansion bolt 81 is heated by an included heater 82, and expanded in a lengthwise direction. Then, air 83 is introduced into a cover 84 to cool and contract the bolt 81 in the lengthwise direction. A pushing and pulling piece 85 made of steel is moved by the expansion and contraction of the bolt 81 in the lengthwise direction to regulate a lip interval, or to particularly finely regulate it. The bolt 81 is heated or cooled by changing a voltage based on thicknesses of parts of a resin film and operating a heater or the air. The regulator B is adopted suitably for a resin relatively difficult to be controlled in thickness of the film such as, for example, a polyethylene or ethylene-vinyl acetate copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lip clearance adjustment device for a T-type extrusion die (T die) used for forming a film from a synthetic resin such as polyethylene, and more particularly, to a method for shortening the fine adjustment of the thickness of a resin film. The present invention relates to a lip clearance adjustment device for a T-die that can be performed with high accuracy and time.

[0002]

2. Description of the Related Art There are a T-die method and an inflation method for forming a resin film such as polyethylene or polypropylene. In the T-die method, a resin film such as polyethylene is extruded and formed, and while the formed resin film is hot, it is superimposed on metal foil, cellophane paper, kraft paper, or the like, pressed with a roll, laminated, fertilized, and damped. It is used for manufacturing bags and the like, and is also widely used for packaging materials such as medicine packaging materials and food packaging materials.

In this T-die, it is essential to adjust the extrusion width and thickness of the resin film. Conventionally, there are an inner deckle type and an outer deckle type as means for adjusting the extrusion width. For the inner deckle type, for example, the inner deckle is placed at the round part of the T-die, and the inner deckle bar is placed at the lip part,
The inner deckle and the inner deckle bar regulate the width of the resin while preventing leakage of the molten resin.

FIG. 3 is a schematic sectional view of a front part showing an example of the above-mentioned inner deckle type T-die. In the figure, 11 is a T-die main body, 12 is a manifold part,
13 is a round portion, 14 is a lip portion, 15 is an inner deckle, 15a is a first stage inner deckle (embedded inner deckle), 15b is a second stage inner deckle (inner deckle with a flag), 16 is an inner deckle bar, and 17 is an inner deckle bar. Each side plate is shown. C is an extruder.

[0005] In FIG. 3, the arrows indicate the flow of the resin,
The molten resin extruded from the extruder C flows into the round part 13 via the manifold part 12, the flow width of the resin is regulated by the inner deckle 15, and finally the inner deckle rod 16 arranged on the lip part 14. The width of the resin is strictly determined, and the thickness of the resin is controlled by the lip interval of the lip portion 14, whereby a resin film is obtained.

In the T-die shown in FIG. 3, the inner deckle 15 has a first-stage inner deckle (embedded inner deckle).
It is of a two-stage inner deckle type of 15a and a second-stage inner deckle (inner deckle with flag) 15b. By making the inner deckle two-stage, individual adjustment of the inner deckle becomes possible, The adjustment of the extrusion width of the resin can be facilitated, and the generation of ear height (ear balls generated at both ends of the obtained film) can be prevented.

On the other hand, in the outer deckle type, for example, a jig is attached to the outer surface of the lip portion of the T-die so as to be press-fitted with a clamp, and the seal portion in the jig is brought into close contact with the lip to prevent resin leakage. The width of the resin is regulated. Thus, a resin film having a certain width is obtained from the molten resin.

[0008] The thickness of the resin film is adjusted by adjusting the lip interval of the lip portion which is the resin outlet of the T-die. The lip gap is adjusted by using a plurality of lip clearance adjustment bolts provided on the nip roll side in the width direction of the T die and automatically or manually adjusting the lip clearance adjustment bolts. Is adjusted to set the thickness of the resin film, and the resin film is extruded from the lip at a constant temperature and molded.

The resin film thus obtained at the start of molding is wound on a roll, and the thickness of each part of the roll on which the resin film is wound is measured. , Calculate the thickness deviation, T
A plurality of heaters installed in the width direction of the die adjust the resin temperature of each portion to correct uneven thickness.

However, it takes time to correct the uneven thickness by adjusting the resin temperature of each part, and during this time, a resin film having a non-uniform thickness (300 m / m) wound up at a high speed.
Min) was wasted.

In the T-die method, it is necessary to adjust the thickness of the resin film during operation in addition to the adjustment of the thickness at the time of starting the resin film molding. In other words, generally, the range in which one heater controls the temperature is:
Normally, 4 to 5 lip clearance adjustment bolts are installed. If there is unevenness in the film within the range of one heater, the lip clearance adjustment bolt is used to finely adjust the lip interval (correction). )There is a need to.
Conventionally, this fine adjustment of the lip interval has required fine adjustment after the molding of the resin film was interrupted. For this reason 30
The molding of the resin film must be interrupted for more than
Time loss was great.

Further, the adjustment of the lip clearance adjusting bolt is inefficient and complicated by manual work because the number of bolts is as large as 30 to 60. In addition, since the T-die has a high temperature of 200 to 340 ° C. during operation, the operation of adjusting the bolt is dangerous and the workability is extremely poor.

For this reason, attempts have been made to automate all of the fine adjustment of the lip interval. However, since the automation device is very expensive and requires a high level of skill in handling it, it is not practical. Was.

On the other hand, the synthetic resins used in the T-die method have become very diversified, and high-density polyethylene, medium-density polyethylene, low-density polyethylene, polypropylene,
A wide variety of resins such as ethylene-vinyl acetate copolymer and polyethylene terephthalate are used, and their properties and properties are different. Also, in the resin production method, for example, the characteristics and properties of the synthetic resin obtained also differ depending on the type of the autoclave type reactor and the tubular type reactor.

Therefore, in the conventional T-die method, there is a problem that the thickness tends to be non-uniform depending on the type of resin used, and particularly when polypropylene or ethylene-vinyl acetate copolymer is used. This phenomenon occurs remarkably.

Accordingly, an object of the present invention is to provide a lip clearance adjusting device for a T-die capable of performing fine adjustment of the thickness of a resin film in a short time and with high accuracy.

[0017]

As a result of the study, the inventors of the present invention have studied the use of a stretchable bolt, which is expanded and contracted by controlling the temperature of the stretchable bolt, and the lip interval is finely adjusted based on the stretchable bolt. It has been found that the above object can be achieved.

The present invention has been made based on the above findings, and comprises a telescopic bolt, heating means for heating the telescopic bolt, cooling means for cooling the telescopic bolt, and a cover for covering a part for heating or cooling the telescopic bolt. A push-pull piece for transmitting the expansion and contraction of the telescopic bolt to the lip part, and expanding or contracting the telescopic bolt in the longitudinal direction by heating or cooling the telescopic bolt, and moving the push-pull piece by the expansion and contraction to reduce the lip interval. An object of the present invention is to provide a lip clearance adjusting device for a T-die, which is characterized in that it is adjusted.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a lip clearance adjusting device for a T-die according to the present invention will be specifically described below with reference to the drawings. FIG. 1 is a side view showing one embodiment of a T-die to which the lip clearance adjusting device of the present invention is applied. In the figure, 1 is a T-die main body, 2 is a manifold portion, 3 is a round portion, 4 is a lip portion, 5 is a nip roll, 6 is a cooling roll (cooling roll),
Reference numeral 7 denotes a side plate. A is a lip clearance adjustment device for primary adjustment, and B is a lip clearance adjustment device for fine adjustment (secondary adjustment), which is the lip clearance adjustment device of the present invention.

In the embodiment shown in FIG. 1, a lip clearance adjustment device A for primary adjustment is provided on the nip roll 5 side in the width direction of the T-die, and a lip clearance adjustment device B for fine adjustment is provided on the cooling roll 6 side. ing. The nip roll 5 is made of silicone resin and has a diameter of 300 m.
m is used. The cooling roll 6 is made of metal and cools the temperature of the resin film to about 10 to 15 ° C. by water cooling, and has a diameter of about 800 mm. As described above, since the cooling roll is large, the space on the cooling roll side in the width direction of the T die is narrow. Therefore, conventionally, there was no T die provided with a lip clearance adjusting device on the cooling roll side.

As the lip clearance adjusting device A, the above-described conventional lip clearance adjusting device is used as it is. On the other hand, the lip clearance adjustment device B of the present invention is newly provided. The lip clearance adjustment device B may be provided at the time of manufacturing the T-die or may be provided on the existing T-die. .

FIG. 2 is a schematic sectional view of the lip clearance adjusting device B of the present invention. In the same figure, 81 is a telescopic bolt, 82 is a heating means (heater), 83 is a cooling means (air), 84 is a cover, and 85 is a push / pull sesame.

The extendable bolt 81 is made of special stainless steel, and expands and contracts in the longitudinal direction by heating and cooling. In other words, the telescopic bolt 81 is heated by the included heater 82 and extends in the longitudinal direction, and by introducing the air 83 into the cover 84, the telescopic bolt 81 is cooled and contracts in the longitudinal direction. The steel push-pull piece 85 is moved by the expansion and contraction of the expansion and contraction bolt 81 in the longitudinal direction to adjust the lip interval, particularly to finely adjust it.

The heating and cooling of the telescopic bolts 81 operate the heaters and air by changing the voltage based on the thickness of each part of the resin film wound up on the roll. These operations are performed by remote operation using a touch panel, and the lip intervals of each portion are finely adjusted by simultaneously operating a plurality of lip clearance adjustment devices B.

The lip clearance adjusting device B of the present invention
Is particularly preferably adopted when a resin in which the thickness of the resin film is difficult to control using only the lip clearance adjusting device A, specifically, a polypropylene or an ethylene-vinyl acetate copolymer is used.

[0026]

As described above, the fine adjustment of the thickness of the resin film can be performed in a short time and with high accuracy by the lip clearance adjusting device for a T-die according to the present invention.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a T-die to which a lip clearance adjusting device of the present invention is applied.

FIG. 2 is a schematic sectional view of the lip clearance adjusting device of the present invention.

FIG. 3 is a schematic sectional view of a front part showing an example of a conventional T-die.

[Explanation of symbols]

1, 11: T-die body 2, 12: Manifold part 3, 13: Round part 4, 14: Lip part 5: Nip roll 6: Cooling roll 7, 17: Side plate 81: Telescopic bolt 82: Heating means (heater) 83 : Cooling means (air) 84: Cover 85: Push / pull piece 15 a: First stage inner deckle (embedded inner deckle) 15 b: Second stage inner deckle (Inner deckle with flag) 16: Inner deckle bar A: Primary adjustment lip Clearance adjustment device B: Lip adjustment device for fine adjustment C: Extruder

Claims (3)

[Claims] 1. A telescopic bolt, a heating means for heating the telescopic bolt, a cooling means for cooling the telescopic bolt, a cover for covering a part for heating or cooling the telescopic bolt, and transmitting the telescopic movement of the telescopic bolt to a lip. A lip for a T-die, comprising: a push-pull piece, wherein the telescopic bolt is expanded or contracted in the longitudinal direction by heating or cooling the telescopic bolt, and the push-pull piece is moved by the expansion or contraction to adjust a lip interval. Clearance adjustment device. 2. The lip clearance adjusting device for a T-die according to claim 1, wherein said heating means is a heater contained in said telescopic bolt, and said cooling means is air introduced into said cover. 3. A T-die comprising a plurality of the lip clearance adjusting devices according to claim 1 provided in a width direction.