JPH0550490A - Manufacture of film like cylindrical body - Google Patents

Abstract

PURPOSE:To obtain an excellent seamless film like cylindrical body having no fold. CONSTITUTION:A tubular film 20 is extruded from an annular die and molded in a vacuum molding tank 4 so as to have a predetermined diameter. In this case, the temp. control tank 24 of the tubular film 20 is provided to the front stage of a sizing sleeve 21. The tubular film 20 is gradually cooled by the temp. control tank 24 and subsequently sent to the sizing sleeve 21 to be subjected to vacuum molding by suction force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suitable method for producing a film-like tubular body which is seamless and has no folds.

[0002]

2. Description of the Related Art For functional belts made of synthetic resin used in the fields of precision equipment, electronic equipment, electric equipment, etc., a thin film-like tubular body is required, and such a thin film-like tubular body is required. The present applicant has previously proposed a method for producing a shaped body as Japanese Patent Application No. 3-40244. In this method, a tubular film extruded from an annular die is simply vacuum-formed by a submerged vacuum water tank.

[0003]

However, in the case of vacuum forming with a submersion type vacuum water tank, since the cooling water directly contacts the tubular film, the cooling rate of the film is large and the film is rapidly cooled. There was a problem that the film was resisting at the entrance, causing waviness, deformation, and cutting.

Further, when only the middle portion of the tubular film is nipped by a nip roller in order to pull the tubular film without folds, there is a problem that the circularity of the tubular film becomes poor and nip wrinkles occur. It was The present invention, in view of the above problems, without rapidly cooling the tubular film extruded from the annular die, by feeding at a film temperature in an optimal state for vacuum forming and vacuum forming, a wavy film is generated or It is a first object of the present invention to provide a method for manufacturing a film-shaped tubular body by vacuum forming that does not deform or cut.

The present invention also provides a manufacturing method for forming a thin film-like tubular body with good dimensional accuracy by reducing the film take-up resistance at the time of vacuum forming the film-like tubular body. This is the second purpose. Furthermore,
A third object of the present invention is to improve the roundness of a vacuum formed film and to provide a method for producing a film-shaped tubular body that can be drawn without folding.

[0006]

In order to achieve the above-mentioned first object, the present invention provides a method of forming a tubular film by extrusion from an annular die, and forming it into a predetermined diameter in a vacuum forming tank. A temperature control tank for the tubular film was installed in front of the sizing sleeve, and the temperature of the tubular film was gradually cooled and sent to the sizing sleeve for vacuum forming.

Further, in order to achieve the second object of the present invention, in a method of extruding from a circular die to form a tubular film into a film and forming it into a predetermined diameter in a vacuum forming tank, a sizing sleeve is provided in front of the film. A temperature control tank for the tubular film is provided, and the temperature of the tubular film is gradually cooled and sent to a sizing sleeve for vacuum forming.At this time, a plurality of annular grooves are provided on the film contact wall surface of the vacuum forming tank, We adopted a configuration that reduces the film take-up resistance.

Further, in order to achieve the third object of the present invention, a tubular film extruded from an annular die is formed into a tube having a predetermined diameter, and only a middle portion of the tubular film is nipped by a nip roll. In a method for producing a film-shaped tubular body that is drawn without folding, at least one circular shaped body is inserted into a tubular film in a vacuum forming tank to maintain the roundness of the vacuum-formed tubular film. Adopted the configuration.

[0009]

According to the first aspect of the present invention, the temperature adjusting tank is provided in the preceding stage of the sizing sleeve, and the temperature of the tubular film is gradually cooled and fed into the sizing sleeve. Molding is possible even if the suction force at the time of molding is smaller.

According to the second aspect of the present invention, since a plurality of annular grooves are provided on the film contact wall surface of the vacuum forming tank, the contact area becomes small and the film take-up resistance at the time of forming becomes small. According to the invention of claim 3, when only the intermediate portion of the formed tubular film is nipped and pulled without folding, at least one circular shaped article is inserted into the tubular film in the vacuum forming tank. Therefore, the influence of the nip portion on the vacuum-formed film is eliminated, and the roundness is maintained.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 show a front view and a side view of an apparatus for carrying out the method of the present invention, in which a thermoplastic resin is charged into an extruder 1 and a spiral annular die 3 through a gear pump 2.
The tube film 20 is melt extruded, the tube film is cooled from the outside while the diameter of the tube film is regulated by the vacuum forming tank 4, and then only the middle part of the tube film is nipped by multiple nip rolls 5 without folding. It shows a state in which it is taken and cut into a predetermined size. At this time, the gear pump 2 is for quantitatively guiding the molten resin to the die 3, and a commercially available one can be used.

As shown in FIG. 4, for example, the spiral die 3 is composed of a mandrel 6 having a spiral groove 10 formed on the extruder side and a die body 7, and a gap 8 between them.
A molten resin flows as shown by an arrow and is extruded to the outside from a slit port 9 of the die 3. At this time, spiral groove 10
Is either the mandrel 6 side or the die body 7 side,
Alternatively, they may be provided on both sides, and the position thereof is not particularly limited, but generally, as shown in the figure, the mandrel is used.
It may be installed up to the middle of the die on the extruder side of 6.

The spiral die 3 is provided for the purpose of uniformizing the flow of the molten resin and performing the quantitative extrusion, and the effect is further exerted by the interaction with the gear pump 2. Further, it is preferable that the die 3 is arranged and attached so as to be extruded directly below in order to improve the dimensional accuracy such as the film thickness accuracy and the diameter, but of course the arrangement and installation other than the above may be adopted.

The vacuum forming tank 4 is, for example, as shown in FIG.
It is a structure having a sizing sleeve 21 and a temperature adjusting tank 24 whose inside is depressurized by a vacuum pump or the like, and the inner ring surface of the vacuum forming tank 4, that is, the surface in contact with the tube is made of a material having good smoothness, for example, A plurality of annular grooves 23 and 27 are provided, which are made of metal or fluororesin having a mirror finish. The plurality of annular grooves 23 provided on the inner surface of the sizing sleeve 21 have relatively large dimensions (for example, a width of 2 m
m, depth 0.5 mm), pores 22 (for example 1 mm
60 pieces are provided in the diameter and circumferential direction. The annular groove 27 provided on the inner surface of the temperature / adjustment tank 24 has a relatively small size (for example, a width of 1 mm and a depth of 0.5 mm) and is appropriately provided in a plurality of stages. The dimensions of these grooves and holes are not particularly limited to these numerical values and may be set appropriately.

The temperature control tank 24 may be a general one, but an annular structure having a jacket through which a cooling medium (water, hot water, etc.) flows in and out is preferable. The inner surface of the control tank 24 is coated with Teflon to reduce the contact resistance of the film and to thicken the Teflon coat (for example, thickness 100 to 200 μ) to reduce the heat transfer efficiency and gradually cool the film. .. That is, the temperature of the film can be kept within the optimum molding temperature range. At this time, it is usually controlled by warm water (60 to 80 ° C.) in the control tank 24, but it is also possible to control by the amount of cooling water.

Pores 22 provided in the sizing sleeve 21
Is a decompression chamber 28 provided inside the sizing sleeve 21.
Is sucked by a vacuum pump (for example, a water circulation type vacuum pump) connected to suction ports 29, 29 provided in the decompression chamber 28 to vacuum-form the tubular film. The temperature control tank 24 is provided with hot water inlets / outlets 25, 26 and a temperature sensor (not shown) to control the temperature of the control tank 24.

Further, as shown in FIG. 5, a plate-shaped circular molded body 30, 31 is provided in the tube-shaped film 20 in the vacuum molding tank 4 connected to the mandrel 6 of the die 3. The formed body 31 provided at the position of the outlet of the vacuum forming tank 4 is a nip roll that nips the central portion of the tubular film 20.
It is provided so that the influence of the film 20 deformed into a flat shape by 5 does not affect the film 20 at the time of vacuum forming. On the other hand, the molded body 30 provided corresponding to the position of the inlet of the vacuum forming tank 4 guides the tubular film 20 extruded from the die 3 so as not to shrink too much before entering the vacuum forming tank 4. Is.

Therefore, by providing the molded bodies 30 and 31, the roundness of the tubular film at the time of vacuum molding is secured. The molded bodies 30 and 31 are not limited to disk shapes, and may be conical shapes. Occurs when the tube-shaped film is nipped by the nip roll 5 into a state close to a flat shape by being connected to the circular shaped body 31 and provided with a conical guide 32 consisting of two pieces corresponding to the axial end of the nip roll 5. Prevents easy nip wrinkles.

The take-up portion 13 has one or a plurality of nip rolls 5. The nip roll 5 nips only the intermediate portion of the tubular film 20 and takes it in a shape as shown in FIG. Film
There will be no folds at both ends 14,14 of 20. At this time, if the tubular film 20 is thin or has no elasticity, it will be flat and creaseable as a whole when the middle part is nipped, so the material and thickness of the tubular film 20, waist, elasticity, etc. It may be meaningless to adapt unless it has a certain value. In short, any material can be applied as long as it has elasticity and waist to the extent that folds are not formed on both sides with the center of the tubular film 20 pressed from both sides.

The nip roll 5 is a pair of rolls 5a and 5b.
The rolls 5a and 5b may have any diameter. The shape and material of the nip roll are not particularly limited, but in this example, by adopting the configuration as shown in FIG. 6, it is possible to cope with a tubular film having any diameter. That is,
FIG. 6 shows a structure in which a large number of annular bodies 15 are provided on the core 16 of the nip roll 5. When the annular body 15 is left only in the main part and the others are removed, depending on the number of removed annular bodies 15. It can be used for tubular films of any diameter.

For example, it is possible to leave the annular body 15 in the portion surrounded by the reference numeral 17 and remove the others, and it is also possible to leave the portion surrounded by the reference numeral 18 and remove the other, and the tubular shape. It is convenient because it can be used immediately depending on the size of the film. The material of the nip roll 5 can be selected and used as appropriate such as metal and rubber, but usually, one roll 5a is made of metal,
Rubber is used for the other rolls 5b, or both rolls 5a, 5b are made of rubber. Even when a large number of annular bodies 15 are used as in this example, the material of each annular body may be appropriately determined as in the above. It is preferable to have a plurality of nip rolls 5 so as to prevent shaking and the like, but of course one piece is also applicable.

The tubular film thus taken off by the nip roll 5 is cut into a predetermined length along the circumferential direction of the tube. The cutting member 19 can be exemplified by a blade cutter, a hot wire cutter, etc. and is not particularly limited. It is used as, for example, the above-mentioned functional belt as a film-shaped tubular body of a cut tube-shaped film, or is used for other appropriate uses.

The gear pump 2 and the spiral die 3 described above may be provided if necessary.
May be omitted, and a normal annular die may be used instead of the spiral die 3. However, in order to obtain a tubular film which is excellent in dimensional accuracy such as thickness and diameter and has a better surface condition, it is more preferable to use the configuration as shown in FIGS.

Examples of the material of the cylindrical body according to the present invention include thermoplastic resins such as polycarbonate, polyester, polyamide such as nylon 12, and thermoplastic resin such as polyether sulfone, but there is no particular limitation, and any material that can be melt extruded may be used. Can be used for. Further, addition of a conductive substance such as carbon black or graphite or other suitable filler to such material may be appropriately determined depending on the intended use, and other suitable third component may be added. None of them are within the scope of the present invention.

Further, as the use of the film-shaped tubular body according to the present invention, as mentioned above, functional belts in the fields of precision equipment, electronic equipment, electrical equipment and the like are suitable, but there is no particular limitation and application to all other fields. Is expected. (Example 1) Polycarbonate resin with L / D = 29 is 65 mm
The mixture was put into an extruder, introduced into a spiral annular die as shown in FIG. 4 through a gear pump, and melt-extruded into a tube shape directly under a slit port (600 mm). Then, the tubular film was gradually cooled by a temperature control tank in a vacuum forming tank having an inner diameter of 500 mm, and the tubular film was vacuum-formed by a sizing sleeve. At this time, insert two circular moldings with an outer diameter of 480 mm into the tubular film to be molded, and
Nip rolls of 3 mm were used to nip and take out only the middle part. The decompression chamber of the sizing sleeve was sucked at −400 mmHg. The contact resistance in the vacuum forming tank was reduced, and a uniform film with an excellent surface condition and excellent dimensional accuracy could be formed. The film-shaped film-shaped tubular body has a diameter of 500 mm and an axial length of 400.
mm, thickness 150 μ, circumference difference of diameter of such a tubular body is 200 μ
Below, thickness variation is 3μ or less, surface roughness is 1-2μ
It was about.

The tubular body thus produced was suitable as a functional belt for electronic equipment, electric equipment, copying machines, precision equipment and the like.

[0027]

According to the present invention, when a tubular film is extruded from an annular die to control the temperature in a tube state, the contact resistance in the vacuum forming tank is reduced, and vacuum forming is performed with a smaller suction force. Then, insert a circular molded body into the tubular film to ensure the roundness at the time of molding, use the nip roll to nip only the middle part of the tubular film, pull it without folds, and cut it to the specified size. Since the film-shaped tubular body is manufactured, the obtained film-shaped tubular body has no joints and no folds, has excellent dimensional accuracy, and has good surface smoothness. Is also good.

[Brief description of drawings]

FIG. 1 is an overall front view showing an embodiment of an apparatus for carrying out the method of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is an explanatory diagram of a nip state.

FIG. 4 is a partially cutaway perspective view of a spiral annular die.

FIG. 5 mainly shows a cross-sectional view of a vacuum forming tank.

FIG. 6 is a plan view of a nip roll.

[Explanation of symbols]

 1 Extruder 2 Gear pump 3 Spiral annular die 4 Vacuum forming tank 5 Nip roll 20 Tubular film 21 Sizing sleeve 22 Pore 23 Annular groove 24 Temperature control tank 27 Annular groove 30 Circular molded body 31 Circular molded body

Front page continuation (72) Inventor Naoki Nishiura 163 Morikawahara-cho, Moriyama-shi, Shiga Gunshi Co., Ltd. Shiga Research Institute (72) Inventor Satoshi Wanaka Nakano, Higashi, Konan-shi, Aichi Pref. Gunze Development Business Department Engineering Plastics Business Center (72) Inventor Hiroyuki Ono 3-11-21 Hikawa-cho, Toda City, Saitama Prefecture Ono Manufacturing Co., Ltd. (72) Inventor Masanori Kaku 3-11-21 Hikawa-cho, Toda City, Saitama Prefecture Ono Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A method of forming a tube-shaped film by extrusion from an annular die and forming the tube-shaped film into a predetermined diameter in a vacuum forming tank, wherein a temperature-adjusting tank for the tube-shaped film is provided in front of the sizing sleeve. A method for producing a film-shaped cylindrical body, which comprises gradually cooling the temperature of the film and feeding it into a sizing sleeve for vacuum forming. 2. The method for producing a film-shaped tubular body according to claim 1, wherein a plurality of annular grooves are provided on the film contact wall surface of the vacuum forming tank to reduce the film take-up resistance during forming. 3. A method for producing a tubular film, which comprises extruding a tubular film extruded from an annular die into a tube having a predetermined diameter and nipping only the intermediate portion of the tubular film with a nip roll to draw it without folds. ,
A method for producing a tubular film body, wherein at least one circular shaped article is inserted into a tubular film in a vacuum forming tank to maintain the roundness of the tubular film to be vacuum formed.