JPH0332599A - Film cutting method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for cutting a film, and more specifically, to a method for cutting a film, which improves cutting stability and increases productivity when continuously cutting a film in the transport direction. This invention relates to a method for cutting a film.

<Prior art> In general, in a film that is continuously transported, such as a stretched film that is continuously formed, in order to remove edges or cut into desired strips, a continuous film is continuously transported in the transport direction. Cutting is done in a precise manner.

Conventionally, for stretched film during film production, a cutter was usually installed on the film free path between the conveyor rolls just before the winder, or a cutter was installed on the film free path between the conveyor rolls, or a cutter was installed in the cooling area of the widening machine for horizontal stretching heat treatment, or the widening gripping device was used to remove the cutter. A commonly used method is to install a cutter in the intermediate region between the release of the conveyor roll and between the conveyor rolls or between the conveyor rolls to continuously cut and remove the edges.

However, with conventional cutting methods, if wrinkles occur in the cut section or film tension is applied diagonally to the running direction, a sharp notch will form in the cut surface of the film, and the notch will become the starting point, causing the film to tear. There was a problem. In addition, since the cutting resistance of the film against the cutter is large, it is necessary to apply a certain amount of tension to the film at the cutting part. Therefore, if a notch occurs on the cut surface of the film, the tension will cause the notch to form a tear. There was also the problem that the film could run more easily, which could even lead to film tearing. Such notches occur because the cutter blade momentarily acts on the film being fed in a relatively unfavorable direction due to wrinkles, flapping, or tension fluctuations in the film at the cutting point, and large or sharp notches occur. When this occurs, the film is torn due to propagation from the notch. especially,
In a thin film of 3 μm or less, the tear strength is low, so the tear easily propagates from the notch, and the film is likely to break.

As a means to solve this problem, for example, Japanese Patent Application Laid-Open No. 63
-77697 proposes preventing tension fluctuations in a part of the cutter, but with only this method, for example, 3
It is difficult to cut ultra-thin films of μm or less at high speed without causing tears. In addition, non-contact cutting methods are disclosed, for example, in JP-A-56-151189 and JP-A-60-12.
No. 1090 proposes laser cutting. Since this method is non-contact, there is almost no breakage due to minute tension fluctuations or wrinkles, but since the film is fused at high temperatures, it produces a large amount of black smoke, and the cut edge of the film is fused, resulting in bead-like bulges. When wound as a continuous body, a good winding shape cannot be obtained, and in reality, this method has not been industrialized.

<Objective of the Invention> An object of the present invention is to provide a cutting method that improves cutting stability and increases productivity when cutting a film during high-speed conveyance or during production of thin products.

<Structures and Effects of the Invention> According to the present invention, an object of the present invention is to continuously cut a transported film in the transport direction of the film, and to perform the cutting using high-pressure water sprayed from a narrow nozzle. It is distantly related to the film cutting method characterized by

The principle of cutting with high pressure water applied in the present invention is usually 50
Ultra-high pressure water of 0 to 4000Kg/cr & inner diameter 0.1 to 0
, from a 5 mm nozzle at several times the speed of sound, and the film is cut by this impact energy. Therefore, in the conventional cutting method using a cutter, the film tends to break frequently due to tension fluctuations and wrinkles applied to the cutting edge, but the method of the present invention uses impact energy to cut, so there is no cutting resistance in the running direction of the film. Tears due to minute tension fluctuations or wrinkles are less likely to occur.

Furthermore, the cutting method using a cutter has the problem that chips are generated when cutting the film, and when these chips are rolled up into the film roll, they cause lump-like defects and deteriorate quality, but in the present invention, chips are generated. is greatly reduced, and there are almost no lump-like defects on the film roll. In addition, when cutting using a laser or the like, there is a problem that the cut end of the film melts and bulges into a bead shape.
In the present invention, since cutting is performed at room temperature, there is no problem with beads.

As mentioned above, nozzles that spray ultra-high pressure water are generally used with an inner diameter of about 0.1 to 0.5 mm.
When the purpose is to cut a thin film, a smaller inner diameter is more economical because the amount of water sprayed can be reduced. The pressure varies depending on the properties of the film to be cut, but for a thickness of 10u
A cutting speed of about 500 to 1500 Kg/cd is sufficient for cutting a film of 150 to 200 m/min or less. Further, the water jetting speed may be normally about 0.1 to 1 ρ/min, although it depends on the thickness of the film.

In the present invention, scattered moisture usually adheres to the film during cutting. However, since the sprayed water has strong directionality and the amount of water used is small, the amount of water adhering to the film surface is minute and is usually naturally evaporated and removed while the film is running. However, it is preferable to remove this moisture quickly and reliably; for example, if moisture remains attached for a long time, it may cause some trouble. For example, if there is a lot of moisture attached and this is carried along with the film up to the process of winding it into a roll,
Blocking may occur between the films, which may cause problems when later removed and processed. Therefore, in the present invention, it is preferable to use means for preventing moisture from scattering or for removing moisture.

Although a biaxially stretched film is suitable as the film in the present invention, a -axially stretched film may also be used. The polymer constituting the film is not particularly limited, but crystalline polymers such as aromatic polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyetheretherketones such as PEEK (ICI: trade name), etc. are preferred. The thickness of the film is preferably 10 μm or less, more preferably 3 μm or less, and particularly preferably 0.5 to 2.5 μm.The effects of the present invention are particularly noticeable when the film is easily torn.

Furthermore, one example of the embodiment will be explained using the drawings.

FIG. 1 is a schematic diagram in which a method according to an embodiment of the present invention is applied to an edge cutting step in a film manufacturing process.

In FIG. 1, 1 is an oriented film that is continuously conveyed. 2 and 3 are rolls for conveying the oriented film 1 with ears, which apply an appropriate tension to the film while it is running. In addition, in order to increase the tension stability between the rolls 2 and 3, the rubber roll 4 is partially or completely disposed in the width direction of the roll 3.
It is common to nip at Reference numeral 5 denotes a nozzle for spraying high-pressure water, and a pump unit 6 generates ultra-high water pressure, and the ultra-high-pressure water is supplied via a pressure-resistant hose 7.

Pressure is applied in the surface direction of the film by the water jet during cutting, and a roll 8 is placed at the cutting part to receive this pressure. FIG. 2 is a partial cross-sectional view of the part where the roll 8 is provided, viewed from the film running direction. Grooves 13 are provided in the circumferential direction in the part corresponding to the high-pressure water to be sprayed to prevent the water from scattering. A cover 9 is disposed around the roll 8 and is vacuum-suctioned to prevent moisture from adhering to the film during cutting.

The edges of the oriented film 1 with edges are continuously cut on both sides in the width direction by ultra-high pressure water jetted from the nozzle 5, and the edges 10 are conveyed to a suitable processing machine (not shown). Further, the product portion 11 from which the ears have been removed is wound up as a film roll by a winding machine (not shown). Reference numeral 12 designates an air duct for removing trace amounts of water adhering to the film, which sends room temperature or heated air to the film to evaporate the water adhering to the film before reaching the roll 3.

According to the present invention, it is possible to stably cut even high-speed transport films, thin films, films with low tear strength, and the like. As a result, it is possible to improve productivity at high speed in the film forming process.

<Example> The present invention will be further explained below with reference to practical examples.

Example Using the apparatus shown in Figures 1 and 2, a biaxially stretched polyethylene terephthalate film with a thickness of 1.3 μm that had been biaxially stretched and heat-set at 200°C by a conventional method was transported at a conveyance speed of 20.
Conveyed with roll 2.3 at 0 m/min, inner diameter 9.1 mm
A water pressure of 1500 Kg/- was applied to the nozzle 5 of the film to cut the film edges. At that time, vacuum suction was performed so that the inside of the cover 9 shown in FIG. 1 was -200 n+mAq. Furthermore, hot air of 70° C. was blown from the air duct 12 at a speed of about 1 m/sec to remove moisture adhering to the edges of the film. As a result, the film tear at the cut part is ○~
Extremely stable continuous film formation could be performed once a day. Furthermore, there was no occurrence of any lump-like defects on the surface of the roll on which the film was wound, and no adverse effects due to attached moisture were observed.

Comparative example A conventional cutter was used to cut the ears, and the ventilation duct 1
Continuous film formation was carried out under the same conditions as in Example except that the air supply from No. 2 was stopped.
~7 times/day, resulting in extremely low productivity9
Further, about 5% of the film roll surface had minute defects.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for cutting edges of a film, showing one example of an embodiment of the present invention. FIG. 2 is a partial sectional view of the roll 8 in FIG. 1, viewed from the film running direction. 1: Oriented film with ears, 2.3: Conveyance roll, 4: Nip roll, 5: Nozzle, 6: Pump unit, 7: Pressure resistant hose, 8: Roll, 9; Cover 10: ears, 11:
v High part, 12: Air duct, 13: Groove made in 0-ru 8. Figure 1 Figure 2

Claims (2)

[Claims] (1) A method for cutting a film, characterized in that when the film being transported is continuously cut in the transport direction of the film, the cutting is performed using high-pressure water sprayed from a narrow nozzle. (2) The method for cutting a film according to claim 1, wherein means for removing moisture adhering to the film is provided near the nozzle to remove the moisture.