JPH04193500A - Cutting device for film - Google Patents

Abstract

PURPOSE:To execute cutting with good stability, by providing a means which prevents the film displacement due to the injection press of a high pressure water at cutting time in the state of coming into contact with the face at the opposite side to the face where the slender nozzle of a film is provided and at the vicinity of the slender nozzle. CONSTITUTION:Small type rotating rolls 11-1, 11-2 are arranged before and behind the transfer direction at the nozzle 5 vicinity of the film 1 lower part. The film 1 is thus pushed up upward by the rotating rolls 11-1, 11-2 from the position of the film which travels between transfer rolls 2, 3, and the displacement to the lower part of the film 1 by the high pressure water from the upper part is prevented. In addition, the wrincles in this transfer roll 2 or those of the travelling film 1 coming from the upper stream further are reduced as well.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applied to a film cutting device, and more specifically, it improves cutting stability and productivity when continuously cutting a film in the transport direction. This invention relates to an elevated film cutting device.

<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 centering machine for transverse stretching heat treatment, or in the width extension gripping device (clip). A commonly used method is to install a cutter in the intermediate region between the conveyance roll after release or between the subsequent conveyance rolls to continuously cut and remove the ears.

However, with the conventional cutting method, if wrinkles occur in the cut section or film tension is applied diagonally to the running direction, sharp notches will form on the cut surface of the film, and the notches will easily become the starting point for film tearing. was there. 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 to stretch the film. 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 tear.

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 a wl thin film of μm or less at high speed without causing tearing. In addition, as a non-contact cutting method, for example, Japanese Patent Application Laid-Open No. 56-151189 and Japanese Patent Application Laid-Open No. 60-1
No. 21090 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.

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

<Configuration/Effects of the Invention> According to the present invention, an object of the present invention is to provide an apparatus that continuously cuts a conveyed film with high-pressure water sprayed from a narrow nozzle in the conveyance direction. A film cutting device characterized in that a means for preventing film displacement due to spray pressure is provided in contact with a surface of the film opposite to the surface on which the thin nozzle is provided and in the vicinity of the thin nozzle. achieved.

The principle of cutting by jetting high-pressure water applied in the present invention is that high-pressure water is jetted at ultra-high speed (subsonic speed to several times the speed of sound) from a thin nozzle with an inner diameter of approximately 0.1 to 0.5 mm, and this impact energy is used to This is for cutting film. Therefore, with 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 when using high-pressure water jetting, cutting is performed using impact energy, so there is no cutting resistance in the running direction of the film. Therefore, tears due to minute tension fluctuations or wrinkles are less likely to occur. Furthermore, the method of cutting with a cutter has the problem that chips are generated when cutting the film, and when these are rolled up into the film roll, they create lump-like defects and reduce quality, but when using high-pressure water jetting, the chips are The occurrence is greatly reduced, and there are almost no lump-like defects in the film roll.

Furthermore, when using a fusing method such as a laser, there is a problem in that the cut end surface of the film melts and swells into a bead shape, but when cutting using a high-pressure water jet, there is no problem with beads because the cutting is done at room temperature.

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 thin films, a smaller inner diameter is preferable because the amount of water sprayed is small and the cutting condition is stable.

When cutting a film by jetting high-pressure water, the cutting energy of the high-pressure water is applied perpendicular to the surface of the film to be cut. For example, when cutting from the top of the film, thin films with no rigidity It tries to be displaced downward by the pressure of the high-pressure water jet. Normally, this displacement does not have a direct adverse effect on cutting, but when the film is extremely thin with a thickness of about 5 μm or less, the vertical vibration of the film at the cutting part becomes significant. For this reason, the cut surface is not a straight line, but a sinusoidal, wavy cutting line. Since this part is not a notch, the film will not normally be torn during transport, but if the transport tension is high or has large fluctuations, the film may tear. Especially in the case of ultra-thin films, the film itself is thin and easily tears, so
The frequency of occurrence of the above phenomenon increases.

The above-mentioned vertical displacement of the film varies depending on the properties of the film to be cut, its thickness, conveyance speed, tension, the distance between the conveyance rolls before and after the cutting section, the pressure of the high-pressure water used for cutting, etc., but in order to prevent this, For example, when cutting a film by spraying high-pressure water from above, it is effective to provide a means for preventing the film from being displaced on the lower tray of the film.

It is effective to provide this means near the cutting part, but it may also be a pair of rolls or other rotating bodies, or a pair of fixed objects, such as semicircular fixed plates. Further, the mounting direction may be in the front and back of the narrow nozzle in the film transport direction, or in the left and right direction of the narrow nozzle. However, in the case of an ultra-thin film, contact resistance increases when the film comes into contact with the displacement prevention means, leading to increased running tension and tension fluctuations at the cutting site, so it is preferable to keep the contact area as small as possible. . Further, it is desirable that the distance between the front and rear nozzles of the displacement preventing means or the distance between the left and right sides of the nozzles be as small as possible in order to minimize displacement of the cutting portion. For example, it is desirable to set it as 5-50 mm.

A biaxially stretched film is suitable as the film to be cut by the apparatus of the present invention, but 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 PE and EK (ICI: trade name), etc. It is highly recommended. It is preferable to use a thin film with a thickness of 10 to 20 μm or less, and in particular, if the film is 3 μm or less, the film itself will tear even under low tension, so the effect of the displacement prevention means of the present invention is likely to be exhibited. Further, even if the film is thick, the apparatus of the present invention is effective in applying the apparatus of the present invention to a high-strength film that has a high stretching ratio in the longitudinal or transverse directions and is easily torn.

Further, the present invention will be explained using the drawings.

FIG. 1 is a schematic diagram in which cutting using high-pressure water is generally applied to an edge cutting step in a film manufacturing process. In FIG. 1, 1 is an oriented film that is continuously conveyed. 2,
3 is a roll for conveying the oriented film 1 with ears, which applies an appropriate tension to the film while it is running. Further, in order to improve the tension stability between the rolls 2 and 3, the roll 3 is generally nipped entirely or partially in the middle direction with a rubber roll 4. 5 is a nozzle that injects high-pressure water, and a pump unit 6 generates high water pressure.
High pressure water is supplied via a pressure hose 7.

Here, a water receiver 8 is arranged so that the water that has passed through the cutting 2 of the film does not scatter elsewhere, and by vacuum suction, the water that has passed through the cutting 2 is prevented from adhering to the film.

In addition, if the distance between the nozzle 5 and the film is too large, water will diffuse and the actual cutting diameter will increase, so it is preferably 10 mm or less, and preferably 5 mm or less if there is no problem due to flapping or wrinkles while the film is running. . The angle of the nozzle 5 is usually perpendicular to the film, but in some cases it may be inclined by about 20 to 50 degrees.

The oriented film 1 with ears is continuously cut at both sides in the width direction by high pressure water jetted from the nozzle 5, and the ears 9 are cut continuously.
is transported to a suitable processing machine (not shown). Further, the product portion 10 from which the ears have been removed is wound up as a film roll by a winding machine (not shown).

FIG. 2 shows an embodiment in which the present invention is applied to the edge cutting process shown in FIG. 1, in which small-diameter rotating rolls 11-1.
-2 is arranged. Normally, the rotating rolls push the film upwards from the position of the film running between the transport rolls (indicated by a broken line in the figure) to prevent the film from being displaced downward by high-pressure water from above. This also makes it possible to reduce wrinkles in the running film coming from the transport roll 2 or further upstream.

FIG. 3 shows an example of an embodiment in which the present invention is applied to the edge cutting process, in which semicircular fixing plates 12 are provided at both ends of the water receiver 8, and this is similar to that in FIG. 2. The film is pushed upwards to prevent it from being displaced by high-pressure water from above.

FIG. 4 is a view of the vicinity of the cutting position in FIG. 3 viewed from the film conveyance direction, and shows fixing plates 12-1, 12-
2 is placed.

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 speed up the film forming process and improve productivity.

<example> The present invention will be further explained below by giving examples.

Example After biaxial stretching by a conventional method using the apparatus shown in FIG.
A biaxially stretched polyethylene terephthalate film with a thickness of 1.2 μm heat-set at °C was conveyed with rolls 2 and 3 at a conveyance speed of 150 m for 7 minutes, and a water pressure of 500 kg/- was applied to a nozzle 5 with an inner diameter Q of 15 mm. The edges of the film were cut. In addition, small diameter rotating roll 11-1.11
-2 has an outer diameter of 30 mm and a length of 50 mm, and is placed at a distance of 40 mm from the front and rear of the nozzle! did.

As a result, the vertical vibration of the film at the cutting part was very slight, and the film was torn at the cutting part 0 to 1 time/day, which was extremely stable.

In addition, when the cut surface of the film was observed under a microscope,
The shape was straight and good. Furthermore, there were no lump-like defects on the surface of the roll on which the film was wound, which usually occurs when a cutter is used.

Comparative Example When the small-diameter rolls 11-1 and 11-2 in the example were removed and the edges were cut under the same conditions as in the example, the film at the cut portion was displaced downward by the high-pressure water and vibrated up and down. The cut surface was a sine curve, and there were occasional notches.

Furthermore, the film was torn at the cut portion 2 to 3 times/day, which was more than in Examples.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram in which cutting using high-pressure water is applied to a film manufacturing process. FIG. 2 is a schematic diagram showing an embodiment in which the present invention is applied to the edge cutting process shown in FIG. 1, and is an example in which a rotating small diameter roll is used as a displacement prevention means. FIG. 3 is a schematic view showing one embodiment of the present invention, and is an example in which a semicircular fixing plate is used as the displacement prevention means. FIG. 4 is a view of the vicinity of the cutting position in FIG. 3 as viewed from the film transport direction. 1: Oriented film with edges, 2, 3: Conveyance roll. 4: Nip roll, 5: Nozzle, 6: Pump unit,
7: Pressure resistant hose, 8: Water receiver, 9: Ear, 10: Product department,
11-1.11-2: Rotating small diameter roll, 12.12
-1°12-2: Fixed plate.

Claims (1)

[Claims] 1. In an apparatus that continuously cuts a transported film in the transport direction using high-pressure water sprayed from a narrow nozzle, means for preventing film displacement due to the pressure of the high-pressure water jet during cutting, A film cutting device characterized in that it is provided near the narrow nozzle and in contact with a surface of the film opposite to the side on which the narrow nozzle is provided. 2. The film cutting device according to claim 1, wherein said means is a pair of rolls.