JPH04278327A - Manufacture of film-like tubular body - Google Patents

Abstract

PURPOSE:To provide proper manufacturing method for obtaining excellent film-like tubular body having neither seam nor fold. CONSTITUTION:When a tubular film 20 extruded from an annular die is formed, the constitution, wherein the tubular film is taken without making folds by nipping only the intermediate part of the tubular film 20 with nip rolls 5 after the film is cooled to a predetermined diameter under tubular state and, after that, cut to the predetermined dimensions.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preferred method for producing a film-like cylindrical body that is seamless and has no creases.

0002

[Prior Art] For example, in the fields of precision equipment, electronics, electrical equipment, etc., there is a demand for the development of functional belts made of synthetic resin. The mainstream was those that were joined together in the shape of a shape, but these had problems such as the joints making it difficult to create a flexible design and not meeting market needs in terms of functionality.

[0003] Therefore, it was decided to pursue these functional belts that have no seams and no creases.
A method of manufacturing a cylindrical body by centrifugal molding, or a method of manufacturing a cylindrical body by forming a film on a tube-shaped film and then cutting it into a predetermined size while taking it off using a sponge-like soft take-up roll or the like to avoid creases. A film-like cylindrical body used for functional belts and the like has been manufactured by this method.

0004

[Problems to be Solved by the Invention] However, in the conventional methods described above, a tubular film with a relatively thin wall tends to become flat, and therefore creases are likely to occur. It was difficult to manufacture a cylindrical body.

Furthermore, these functional belts are generally required to have excellent dimensional accuracy in terms of thickness, diameter, etc., good smoothness, and good surface condition, and it has been necessary to pursue these qualities.

Based on this technical background, the present inventors have repeatedly conducted various studies in order to obtain a film-like cylindrical body suitable for, for example, functional belts, and as a result, have finally arrived at the present invention. Therefore, an object of the present invention is to provide a suitable manufacturing method for obtaining an excellent film-like cylindrical body that is seamless and has no creases.

[0007]

[Means for Solving the Problems] As a means for achieving the above object, the present invention provides, when forming a tubular film by extruding it from an annular die, after cooling the tubular film to a predetermined diameter. A configuration was adopted in which only the middle part of the tubular film was nipped using nip rolls, taken off without creases, and cut into predetermined dimensions. At this time, in order to obtain a film-like cylindrical body with excellent dimensional accuracy, smoothness, and a good surface condition, it is necessary to extrude it from a spiral-shaped annular die, and then, if necessary, to form a tube in a submerged vacuum water tank. It is desirable to cool the film externally, and even more preferably to extrude it from a spiral annular die via a gear pump if necessary. Furthermore, it is more desirable that a plurality of nip rolls be installed.

[0008]

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 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 thermoplastic resin is introduced into an extruder 1 and transferred to a spiral annular die 3 via a gear pump 2. The tubular film is melt-extruded as a tubular film 20, cooled from the outside while regulating the diameter of the tubular film in a submerged vacuum water tank 4, and then nipped only at the middle part of the tubular film using a plurality of nip rolls 5 to eliminate creases. This shows the state in which it is taken over and cut into predetermined dimensions. At this time, 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, the spiral die 3 consists of a mandrel 6 with spiral grooves 10 carved on the extruder side and a die body 7, and the gap 8 is filled with molten resin. flows like an arrow and dice 3
is pushed out from the slit opening 9. At this time, the spiral groove 10 is formed on the mandrel 6 side or on the die body 7 side.
It may be provided on either or both sides, and its position is not particularly limited, but generally it may be provided on the extruder side of the mandrel 6 up to the middle of the die as shown in the figure. Note that this spiral die 3 is provided for the purpose of uniformizing the flow of the molten resin and performing quantitative extrusion, and its effect is further demonstrated by interaction with the gear pump 2. Also, dice 3
In order to improve dimensional accuracy such as film thickness accuracy and diameter, it is preferable to arrange and attach it so as to push it out directly below, but of course, other arrangements other than the above may also be used.

As shown in FIG. 5, for example, the submerged vacuum water tank 4 has a structure including a sizing sleeve 19 and a cooling water tank 24, the inside of which is reduced in pressure by a vacuum pump or the like, and the inner ring surface of the sizing, that is, The surface in contact with the tube is made of a material with good smoothness, such as mirror-finished metal or fluororesin, and is provided with pores. The pores always keep the surface in contact with the tubular film in a reduced pressure state, thereby regulating the outer diameter of the tubular film to be constant along the inner ring surface of the sleeve. If necessary, supply a small amount of water to the inner ring surface of the sleeve to form a thin water film between the inner ring of the sleeve and the outer surface of the tubular film. It can also be expected to improve the contact resistance with the surface. The inner ring surface is an important element to improve the surface condition of the tubular film, and by using such a submerged vacuum water tank, the outer diameter of the tubular film is accurately regulated and cooled, while also maintaining its surface condition in good condition. Become something. At this time, there is no particular restriction on the ratio of the outer diameter of the slit 9 in the die 3 to the inner diameter of the sizing sleeve 19 of the vacuum water tank, but it is easier to obtain a product with excellent thickness accuracy if the ratio is as close as possible. As a preferable value of the above-mentioned ratio, about 1.0 to 1.2 can be exemplified.

[0012]Also, although the cooling water tank is a general type and has a structure in which the outer surface of the tubular film is in direct contact with water,
It may be an annular structure having a jacket into which a cooling medium enters and exits, and is not particularly limited.

FIG. 5 shows a preferable example of such a submerged vacuum water tank 4, in which 19 is a sizing sleeve, at least the inner ring surface 28 of which is made of mirror-finished brass in this example, and is made of thin metal. A hole 21 is provided. This pore 21 is in a reduced pressure state and reaches the inner ring surface 28 of the sleeve 19 via a reduced pressure chamber 22 by a vacuum pump (for example, a water circulating vacuum pump) or the like. Reference numeral 23 denotes a supply section for water, etc., from which water, etc. is supplied, and a thin water film is formed between the outer surface of the tubular film 20 and the inner ring surface 28 of the sleeve. At this time, water droplets enter the vacuum chamber 2 from the pores 21.
2, but there is no particular problem, and in this case, it is possible to prevent the intrusion as much as possible by adjusting the degree of vacuum, water amount, pore size, etc. 24 is a cooling water tank in which water is circulated from an inlet 25 to an outlet 26. The water in the water tank 24 and the outer surface of the tubular film 20 are in direct contact, and at this time, if the sealing mechanism 27 of the water tank 24 is insufficient, water may ooze out through the tubular film. Of course, even if water oozes out, it does not particularly affect the quality.

The take-up section 13 has one or more nip rolls 5.
Since only the middle portion of the tubular film 20 is nipped and taken off into the shape as shown in FIG. At this time, if the tubular film 20 is thin or has no elasticity, if the middle part is nipped, the whole will become flat and prone to creases, so the material, thickness, elasticity, etc. of the tubular film 20 may If it does not have a certain value, there may be no point in adapting it. In short, any material can be used as long as it has enough elasticity and stiffness to prevent creases from forming on both sides when the center of the tubular film 20 is pressed from both sides. The nip roll 5 is a pair of rolls 5
The diameters of the rolls 5a and 5b may be arbitrary. There are no particular restrictions on the shape or material of the nip roll, but in this example, by adopting the configuration as shown in FIG. 6, it is possible to handle a tubular film of 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. By leaving only the essential parts of the annular bodies 15 and removing the rest, the annular bodies 15
It is possible to handle tubular films of any diameter depending on the number of removed. For example, the annular body 1 of the part surrounded by the symbol 17
You can leave 5 and remove the others, or you can leave the code 1
It is also possible to leave the part surrounded by 8 and remove the rest, which is convenient and can be done immediately depending on the diameter of the tubular film. The material of the nip roll 5 can be selected from metal, rubber, etc., but usually one roll 5a is made of metal and the other roll 5b is made of rubber, or both rolls 5 are made of metal.
Both a and 5b are made of rubber, and the annular body 1 as in this example
5, the material of each annular body may be appropriately determined as described above. It is preferable to have a plurality of nip rolls 5 to prevent shaking, etc., but of course one
It can also be applied to individuals. The tubular film thus taken up by the nip rolls 5 is cut into predetermined lengths 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. The cut tubular film may be used as a film-like cylindrical body, for example, in the above-mentioned functional belt, or for other appropriate uses.

[0015] As described above, it is preferable that such a film-like cylindrical body has smoothness and a good surface condition, but this is not particularly limited.

The gear pump 2, spiral die 3, and submerged vacuum water tank 4 described above may be provided if necessary, or the gear pump 2 may be omitted, or a normal annular die may be used in place of the spiral die 3. Alternatively, instead of the submerged vacuum water tank 4, an inside mandrel method, a reduced pressure former method, or any other appropriate method may be used to regulate the diameter or cool it, and there are no particular limitations. However, in order to obtain a tubular film with excellent dimensional accuracy in terms of thickness, diameter, etc., and a better surface condition, the structures shown in FIGS. 1 and 2 are more preferable.

The above-mentioned reduced pressure former system has a structure in which cooling water 31 passes through the former 30 as shown in FIG. 7, while the reduced pressure section 29 directly reaches the inner ring surface of the former via a separate route. This limits the outer diameter of the tubular film 20.

Examples of the material for the cylindrical body according to the present invention include polycarbonate, polyester, polyamide such as nylon 12, and thermoplastic resin such as polyether sulfone, but there is no particular restriction, and any material that can be melt extruded may be used. It can be used for Furthermore, it is perfectly acceptable to add conductive substances such as carbon black and graphite and other appropriate fillers to such materials, as long as they are determined as appropriate depending on the application, and it is also possible to add other appropriate third components. All are within the scope of the present invention.

As mentioned above, the film-like cylindrical body according to the present invention is preferably used as a functional belt in the fields of precision equipment, electronics, electrical equipment, etc., but there is no particular restriction, and it can be applied to all other fields. is expected.

Further, in the present invention, the expression ``film-like cylindrical body'' is used in all cases, but it goes without saying that the term ``film-like'' herein includes all sheet-like objects.

[0021] The above description has been limited to exemplifying preferred embodiments of the present invention, and it goes without saying that the present invention is not limited to these descriptions.

Next, more specific embodiments of the present invention will be described.

(Example 1) Polycarbonate resin L/
The material was put into a 65 mm extruder at D=29, passed through a gear pump, introduced into a spiral annular die as shown in FIG. 4, and melted and extruded into a tube directly from a slit opening (outer diameter 155 mm). Next, the diameter of the tubular film was regulated and cooled using a sizing sleeve in a submerged vacuum tank with an inner diameter of 158 mm, and 12 nip rolls with a width of 80 mm were used to nip only the middle part and take it off without creating creases. Cut to length with a hot wire and have a diameter of 1
A film-like cylindrical body having a diameter of 58 mm, an axial length of 400 mm, and a thickness of 150 μm was obtained. The diameter of such a cylindrical body is the difference in circumferential length: 20
The thickness was less than 0 μm, and the variation in thickness was less than ±5 μm, and the dimensional accuracy was extremely excellent. Furthermore, the surface roughness was approximately 1 to 2 microns, and the surface condition was extremely good.

(Example 2) In the same manner as in Example 1, polyester resin (polyethylene terephthalate) was extruded into a tube directly below a spiral annular die with an outer diameter of 144 mm, and passed through a sizing sleeve in a submerged vacuum water tank with an inner diameter of 148 mm. After that, only the middle part is nipped and taken out using 12 nip rolls with a width of 60 mm, and cut into 300 mm lengths with a diameter of 148 mm, an axial length of 300 mm, and a thickness of 1.
A film-like cylindrical body having a diameter of 0.00 μm was obtained.

The diameter of the cylindrical body had a circumferential length difference of 200 μm or less, and the thickness had a variation of 3 μm or less, showing extremely excellent dimensional accuracy. Furthermore, the surface roughness was approximately 1 to 2 μm, and the surface condition was extremely good.

The submerged vacuum water tank used in Examples 1 and 2 above is as shown in FIG. 5, and a small amount of water is supplied through the upper part 23 at the location where the tubular film faces the sizing sleeve. As a result, a thin water film was formed, and the water acted as a lubricant, which was convenient for obtaining a better surface condition.

Further, the nip roll has a nip portion as shown in FIG. 6 in which a large number of annular bodies each having a width of 10 mm are provided. In Example 1, eight such annular bodies were used, in Example 2, six such annular bodies were used, and in the other embodiments, eight such annular bodies were used. It was removed and used. Both of these nip rolls were made of a material coated with urethane rubber. By doing so, both Examples 1 and 2 could be operated using the same device by simply increasing or decreasing the number of annular bodies, which was extremely convenient.

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

[0029]

Effects of the Invention: When forming a tubular film by extruding it from an annular die, the tubular film is cooled to a predetermined diameter in a tube state, and then only the middle part of the tubular film is nipped with nip rolls to avoid creases. Pick up,
Since the film-like cylindrical body is manufactured by cutting into predetermined dimensions, the obtained film-like cylindrical body has no seams and creases, has excellent dimensional accuracy, and has good smoothness. Products with good surface conditions can be obtained, and the productivity is also good.

[Brief explanation of the drawing]

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 the spiral annular die.

FIG. 5 is a sectional view of a submerged vacuum water tank.

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

FIG. 7 is a sectional view showing another embodiment of a cooling means for a tubular film.

[Explanation of symbols]

1 Extruder 2 Gear pump 3 Spiral annular die 4 Immersion type vacuum water tank 5 Nip roll 19 Sizing sleeve 20 Tubular film 24 Cooling water tank

Claims (4)

[Claims] Claim 1: When forming a tubular film by extruding it from an annular die, the tubular film is cooled to a predetermined diameter in a tube state, and then only the middle part of the tubular film is nipped with nip rolls and taken off without creases. 1. A method for producing a film-like cylindrical body, characterized in that the cylindrical body is obtained by cutting it into dimensions. 2. The method for producing a film-like cylindrical body according to claim 1, wherein the tubular film is formed by extruding from a spiral annular die with or without a gear pump. 3. The method for producing a film-like cylindrical body according to claim 1, wherein the tubular film is made to a predetermined diameter and cooled in a submerged vacuum water tank. 4. The method for producing a film-like cylindrical body according to claim 1, wherein a plurality of nip rolls are provided.