JP2520632Y2 - Film manufacturing equipment - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a film manufacturing apparatus for forming a thermoplastic resin into a film, and in particular, a molten thermoplastic resin is extruded from a die, and bubbles extruded from the die are discharged to the downstream side of the die. The present invention relates to a film manufacturing apparatus adapted to be brought into contact with a mandrel provided to be stabilized.

[0002]

2. Description of the Related Art Conventionally, a T-die method or an inflation method has been generally used to form a thermoplastic resin into a film.

However, in the case of the T-die method, the manufacturing cost is high, and if the take-up speed during film formation is high, the neck-in becomes large and the thickness of the film to be formed is limited, so that a thin film is formed. Was difficult to produce, and in particular, it was difficult to form a thermoplastic resin such as ethylene vinyl alcohol copolymer or nylon having a very low melt tension into a film.

Further, the production cost is lower in the case of using the inflation method than in the case of using the T-die method, but even in this method, it is difficult to form a thermoplastic resin having a very small melt tension as described above into a film. Met.

Therefore, in recent years, even in the case of using a thermoplastic resin such as ethylene vinyl alcohol copolymer or nylon having a very low melt tension in the inflation method, it is possible to successfully form a film. Therefore, various research and development were conducted.

As a result, as shown in Japanese Patent Publication No. 57-201330, a mandrel is provided on the downstream side of the die for extruding the molten thermoplastic resin so that the bubbles extruded from the die come into contact with the mandrel. In the inflation method, the thermal conductivity of the portion of the mandrel that comes into contact with the bubbles is 1.0 kcal / mhr.
What was made to be below ℃ was developed. Then, as shown in this publication, if a mandrel having a thermal conductivity of 1.0 kcal / mhr ° C. or less at a portion in contact with the bubble is used, the bubble extruded from the die is stabilized by the mandrel. The uneven cooling in the produced film is suppressed by suppressing uneven cooling due to the mandrel, and even when a thermoplastic resin having a very small melt tension such as ethylene vinyl alcohol copolymer or nylon is used, Thin films are now available.

Here, the thermal conductivity of the portion of the mandrel which is in contact with the bubble is 1.0 kcal / m.
In order to reduce the temperature to hr ° C. or lower, conventionally, as shown in the publication, the mandrel is formed of wood or paper having a low thermal conductivity, or the surface of the mandrel which comes into contact with bubbles has a low thermal conductivity of cotton cloth, It was performed by coating with a nonwoven fabric such as wool or meta-aramid fiber.

However, when the mandrel is formed of wood, paper or the like, the mandrel has poor wear resistance and heat resistance, the mandrel is damaged in a short period of time due to contact with the bubble, and the mandrel contacting with the bubble is deteriorated. Even when the surface is covered with a non-woven fabric such as cotton cloth, wool, or meta-aramid fiber, the covering material covering the surface of the mandrel does not have sufficient abrasion resistance or heat resistance. Have gradually been worn and fluffed, and are cured by heat, and these coating materials are gradually deteriorated, resulting in uneven thickness and wrinkles in the produced film, which makes it impossible to produce a stable film. .

Further, in order to perform stable film production, when the mandrel or these coating materials for coating the surface of the mandrel are replaced, the apparatus for producing the film must be stopped each time, Even when the operation of the device is restarted, it takes time for the film production to stabilize, and if these replacements are frequently performed, the production efficiency of the film is significantly reduced and the waste of the thermoplastic resin as the raw material is reduced. There was a problem that there were many.

[0010]

This invention was made in order to solve various problems in forming a thermoplastic resin into a film. The thermoplastic resin in a molten state is extruded from a die and then extruded from this die. In the film manufacturing apparatus by the inflation method, in which the formed bubbles are brought into contact with the mandrel provided on the downstream side of the die, as described above in the case of coating the surface of the mandrel in contact with the bubbles with a material having a low thermal conductivity. The problem is to solve the problem.

That is, the present invention is a study on the coating material for coating the surface of the mandrel which comes into contact with the bubble in the film manufacturing apparatus by the inflation method as described above. The coating material does not gradually wear and fluff, and does not gradually deteriorate due to heat curing, the coating material can be used stably for a long period of time, and stable film production can be continuously performed for a long period of time. It is an object of the present invention to provide a film manufacturing apparatus that improves the production efficiency of a film and reduces the waste of a thermoplastic resin as a raw material.

[0012]

In the present invention, in order to solve the above problems, a molten thermoplastic resin is extruded from a die 1, and a bubble 2 extruded from the die 1 is discharged downstream of the die 1. In the film manufacturing apparatus, which is brought into contact with and stabilized by the mandrel 3 provided on the side, at least the bubble 2 of the mandrel 3 is provided.
The surface in contact with is coated with the coating material 4 made of a string-like product or a woven or knitted fabric made of para-aramid fiber.

Here, the mandrel 3 in contact with the bubble 2
The coating material 4 made of para-aramid fiber was used to coat the surface of the mandrel because the para-aramid fiber was used to coat the surface of the mandrel 3 conventionally with cotton or wool. This is because it is superior in wear resistance and heat resistance to meta-aramid fiber and the like.

However, even if the para-aramid fiber is composed of the para-aramid fiber as described above, the para-aramid fiber forming the non-woven fabric is gradually fluffed by the contact with the bubble 2 to be manufactured. Since uneven thickness, wrinkles, etc. occur in the film, making it impossible to manufacture a stable film, in the present invention, a string-like product or a woven or knitted product was formed using the para-aramid fiber as described above. I chose to use one.

Then, by using the covering material 4 composed of a string-like product or a woven or knitted fabric composed of the para-aramid fiber as described above,
When coating the surface of the mandrel 3 that comes into contact with the bubble 2, this coating material 4 is wrapped around or covered on the surface of the mandrel 3 that comes into contact with the bubble 2, and the bubble 2 extruded from the die 1 is the surface of the mandrel 3. To be in contact with this coating material 4.

The string-like article used for coating the surface of the mandrel 3 which comes into contact with the bubble 2 is a non-twisted yarn if it is made of para-aramid fiber as described above.
Twisted single yarn and draw-aligned yarn made by combining these
It may be any string-shaped product such as a twisted yarn, a braid, or a cord or rope obtained by combining a plurality of these.

[0017]

In the film producing apparatus according to the present invention, in the mandrel 3 provided on the downstream side of the die 1 as described above, at least the surface of the mandrel 3 in contact with the bubble 2 is made of para-aramid fiber. Since the coating material 4 made of a string-like product or a woven or knitted material is used for coating, the coating material 4 reduces the thermal conductivity on the surface of the mandrel 3 that comes into contact with the bubbles 2.

Therefore, the bubble 2 extruded from the die 1 comes into contact with the surface of the mandrel 3 covered with the coating material 4 made of a string-like article or woven or knitted fabric made of para-aramid fiber as described above. However, the uneven cooling of the mandrel 3 is suppressed, the uneven thickness of the produced film does not occur, and the bubble 2 is stabilized by the contact with the mandrel 3, and the ethylene vinyl alcohol copolymer An ultrathin film can be obtained even when a thermoplastic resin having a very low melt tension such as coalescence or nylon is used.

Further, the coating material 4 made of a para-aramid fiber used for coating the surface of the mandrel 3 which comes into contact with the bubbles 2 and made of a woven or knitted material, has a wear resistance and Since it has excellent heat resistance, the coating material 4 does not wear and fluff when contacted with the bubbles 2 or is hardened and deteriorated by heat, and can be used stably for a long period of time. The number of replacements of No. 4 is extremely small, stable film production can be continuously performed for a long time, the production efficiency of the film is improved, and the waste of the thermoplastic resin as a raw material is reduced.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

In the film manufacturing apparatus of this embodiment shown in FIG. 1, a molten thermoplastic resin is fed from an extruder (not shown) to the die 1, and the molten thermoplastic resin thus fed is fed. The resin was extruded above the die 1 at a predetermined extrusion speed V ₁ through an annular slit provided in the die 1.

Then, the bubble 2 thus extruded from the die 1 and formed into a tubular shape is cooled while being guided above the die 1.

Further, in this embodiment, a column 5 is erected from the center of the die 1 upward, that is, toward the downstream side of the bubble 2 in the feeding direction, and the column 5 is placed above the die 1. A first mandrel 3a that is slightly upwardly contracted in a slightly tapered shape is provided at a position slightly above, and a second mandrel that is upwardly tapered is provided at a position further above the first mandrel 3a. 3b is provided, and as shown in FIG. 2, the outer peripheral surfaces of the first and second mandrels 3 are covered with a covering material 4 composed of a string-like article or woven or knitted fabric composed of para-aramid fiber. .

Then, the bubbles 2 sent upward from the die 1 are covered with the covering material 4 composed of a string-like article or a woven or knitted fabric made of the para-aramid fiber as described above. The mandrel 3 was sequentially brought into contact with the outer periphery of each mandrel 3 to stabilize it, and then while the bubble 2 was further cooled, it was wound up at a predetermined take-up speed V ₂ by a roller (not shown) provided above.

Next, concrete Examples 1 and 2 in which a film is manufactured by using the above-described film manufacturing apparatus, and the outer peripheral surfaces of the first and second mandrels 3 are covered. The coating material 4 was compared with a comparative example in which a material other than a string-like article or a woven or knitted material made of para-aramid fiber was used.

In Examples 1 and 2 and Comparative Example, a high-molecular-weight high-density polyethylene (HIZEX 7000F, manufactured by Mitsui Petrochemical Co., Ltd.) having a specific gravity of 0.950 was used as a raw material for the thermoplastic resin. An extruder manufactured by Placo Co., Ltd. in which the diameter of the resin extrusion port was 40 mmφ was used, and a 75 mmφ spiral die was used as the die 1.

In the column 5 standing upright in the center of the die 1, the diameter of the lower end is 75 mmφ, the diameter of the upper end is 60 mmφ, and the first mandrel 3a is shrunk slightly upward and has a diameter of the lower end. Is 35 mmφ and the upper end has a diameter of 55 mmφ, and a second mandrel 3b bulging upward in a tapered shape is provided.

As the covering material 4 for covering the outer peripheral surfaces of the first and second mandrels 3 provided on the columns 5 as described above, the para-aramid fiber (Japanese aramid fiber) of Example 1 was used. Limited company, Twaron) 100%
Using the braid that twisted 40 pieces of 20 English count twin yarn of
This is wound around the outer peripheral surface of each of the mandrels 3 described above, and in the second embodiment, four 20-type count twin yarns of 100% para aramid fiber (manufactured by Nippon Aramid Co., Ltd., Twaron) are drawn. A straight sleeve of 96 strokes aligned was used, and this was wound around the outer peripheral surface of each mandrel 3 described above. On the other hand, in the comparative example, when coating the outer peripheral surfaces of the first and second mandrels 3, the meta-aramid fiber (manufactured by DuPont, 1-Mex) was 100% and the basis weight was 200 g / m ^2.
This non-woven fabric was used to be wound around the outer peripheral surface of each mandrel 3.

In Examples 1 and 2 and the comparative example, when the film was produced, the take-up speed V ₂ was 100 m / min, and the take-up speed V ₂ and the extrusion speed V ₁ were the ratio (V ₂ / V ₁ ) 13, expansion ratio (BU
R) was set to 3 to produce a film having a thickness of 10 μm.

As a result, each of the first and second mandrels 3
In the comparative example in which the outer periphery of the above was covered with a non-woven fabric composed of meta-aramid fiber, the non-woven fabric was deteriorated after 72 hours of operation, resulting in uneven thickness in the produced film. In Examples 1 and 2 in which the outer periphery of each second mandrel 3 is covered with a braid or knitted fabric made of para-aramid fiber, the produced film has uneven thickness even after operating for 240 hours. It did not occur, and a stable film could be continuously produced.

[0031]

As described in detail above, in the film manufacturing apparatus according to the present invention, the molten thermoplastic resin is extruded from the die, and the bubbles extruded from the die are provided on the downstream side of the die. In contacting and stabilizing in contact with the bubble, the surface of the mandrel in contact with the bubble is covered with a string-like article or woven or knitted fabric composed of para-aramid fiber, and the thermal conductivity of the mandrel surface in contact with the bubble is lowered, Even when the bubble extruded from the die comes into contact with the surface of the mandrel, uneven cooling due to the mandrel is suppressed, and uneven thickness does not occur in the film produced, such as ethylene vinyl alcohol copolymer and nylon. It has become possible to produce an extremely thin film even when a thermoplastic resin having a very low melt tension is used.

Further, in the film manufacturing apparatus according to the present invention, since the surface of the mandrel which comes into contact with the bubble is covered with the string-like article or the woven or knitted fabric made of the para-aramid fiber as described above, Compared with the conventional ones in which the surface of the contacting mandrel is coated with cotton cloth, wool, or non-woven fabric such as meta-aramid fiber, the wear resistance and heat resistance of the covering material are higher, and By contact with the bubbles, the coating material that coats the surface of the mandrel is not worn and fluffed, nor is it hardened and deteriorated by heat, and stable use can be achieved for a long time.

As a result, in the film manufacturing apparatus according to the present invention, it is not necessary to frequently replace the coating material that covers the surface of the mandrel that comes into contact with the bubbles, unlike the conventional case, and stable film manufacturing can be performed for a long time. Since it can be continuously performed, the production efficiency of the film is significantly improved as compared with the conventional one, and the waste of the thermoplastic resin as a raw material is reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a part of a film manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cut front view showing a state in which the outer periphery of a mandrel used in the embodiment is covered with a covering material.

[Explanation of symbols]

 1 Die 2 Bubble 3 Mandrel 4 Covering material

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuo Suzuki 8-13 Shimbashicho, Fuji City, Shizuoka Prefecture Sankyo Kasei Kogyo Co., Ltd. (72) Inventor Masato Saito 8-13 Shimbashicho, Fuji City, Shizuoka Prefecture Kyosei Co., Ltd. (56) Reference JP 61-262115 (JP, A) Actual Kaihei 1-68821 (JP, U) JP 57-20130 (JP, B2)

Claims (1)

(57) [Scope of utility model registration request] 1. A film manufacturing method in which a molten thermoplastic resin is extruded from a die 1, and a bubble 2 extruded from the die 1 is brought into contact with a mandrel 3 provided on the downstream side of the die 1 for stabilization. In the apparatus, at least the surface of the mandrel 3 that comes into contact with the bubbles 2 is coated with a coating material 4 made of a string-shaped article or a woven or knitted fabric made of para-aramid fiber, and the film manufacturing apparatus.