JPH10316776A - Plastic film roll used for vacuum treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart a good unwindability to a plastic film roll used for a vacuum treatment by specifying the expansion power of the roll to a certain value or lower. SOLUTION: This plastic film roll is prepd. so as to have an expansion power of 180 Pa or lower. Pref., the film has a thickness of 0.5-15 μm and is a vacuum-metallizable one, e.g. a polyester film. Such a roll is prepd. by winding the film under such conditions of temp, humidity, and pressure that the distance between layers of the wound film is made as small as possible, the amt. of air entrapped is reduced to as small as possible, and the characteristics of air entrapped are suitable for the vacuum treatment. More specifically, the roll is prepd. by winding and drying while decreasing the winding tension from 24.5 Pa to 19.6 Pa linearly with the increase in the roll diameter and increasing the plane pressure from 539 N/m to 637 N/m linearly with the increase in the roll diameter or without changing the plane pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic film wound body which is subjected to a vacuum treatment in which a plastic film is wound into a roll using a core.

[0002]

2. Description of the Related Art Plastic films are widely used in various applications including magnetic recording applications, electrical insulation applications, printing / graphic applications, photographic applications, and capacitor applications because of their excellent mechanical, thermal, and electrical properties. Used. Particularly, the surface of a plastic film is covered with a magnetic material or a conductive metal thin film under vacuum, and is used for magnetic recording and capacitor applications. In this processing step, a processing method called vapor deposition or sputtering is employed.In this step, a plastic film winding body obtained by winding a continuous body of plastic film into a roll using a core is depressurized in a chamber. While the film is being rewound, one side of the film is cooled by a roll, and the opposite side is treated with the material by vapor deposition or sputtering. When the film is unwound in the vacuum, the air entrapped in the plastic film roll expands due to the pressure difference from the pressure in the chamber, and the film may be shifted laterally on the plastic film roll. . Such a shift causes meandering of the plastic film running in the vacuum chamber, resulting in uneven end faces during winding after vapor deposition or a shift in a margin position during vapor deposition.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic film roll which gives a good rewinding property to a plastic film roll subjected to a vacuum treatment, focusing on the above-mentioned problems. It is in.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies and found that a specific winding state is necessary for the film winding body to run well in the vacuum processing step without winding deviation. Found and arrived at the present invention.

[0005] That is, the plastic film wound layered body of the present invention is one which is subjected to a vacuum treatment wound in a roll having an expansion force of 180 Pa or less.

The thickness of the plastic film is as follows:
The thickness is preferably in the range of 0.5 to 15 μm, and the plastic film is preferably formed by vacuum deposition. Here, the plastic film is, for example, a polyester film.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the plastic wound body of the present invention will be described in more detail. The plastic film wound layer body of the present invention is obtained by, for example, slitting a heat-treated plastic film after biaxial stretching to a predetermined width and length by applying a predetermined tension and / or surface pressure, and winding the film on a core. It is a thing. Since this plastic film winding body is generally wound under atmospheric pressure, air exists between the winding layers. The gap between the winding layers and the amount of entrained air are determined by winding conditions such as winding tension, surface pressure, and speed.
It is determined by the characteristics of the film, such as the film surface roughness and the film rigidity, and the temperature, humidity, pressure, etc. of the air, but the plastic film winding body subjected to the vacuum treatment including all these conditions is wrinkled. The index for winding up without defects such as temperature, humidity, pressure, etc. is such that the gap between the winding layers is as narrow as possible, the amount of entrapped air is minimized, and the characteristics of air itself are also suitable during vacuum processing. If it is possible to wind the film, a plastic film wound body which is subjected to the most preferable vacuum treatment can be obtained.

When the plastic film roll is rewound under vacuum, the air between the plastic film roll layers expands under vacuum due to the pressure difference between the pressure in the chamber (vacuum pressure) and the plastic film roll is removed. Inflate.
This expansion force applies a stress to the film, and the expansion force P (1
0 ³ Pa), the film thickness is t (μm), the radius of the wound body is R (mm), and the stress of the film per sectional area is T (μm).
In the case of (MPa), P = (t × T) / R (1) That is, if the value of P is large, the film floats from the wound body with a stress, so that the plastic film easily shifts during rewinding.

In order to avoid this, for example, Japanese Patent Publication No. Sho 59
A method in which a plastic film wound body is wound in advance under a vacuum as disclosed in JP-A-4335 is proposed as one of the most effective methods. However, in order to take up under vacuum, the take-up device must be placed in a vacuum chamber, and a break in the vacuum state is required every time a product roll is attached or detached. Many. Also,
It is known that since no air is interposed under vacuum during the winding and transporting, there may be strict restrictions on the transport conditions of the plastic film and the like, and it is necessary to finely adjust the degree of vacuum.

The present invention provides a plastic film wound body having good running properties in a vacuum, and has intensively studied a method for reducing the stress T of the film due to the expansion force P of air to suppress running. The present invention has been achieved.
As a result of repeatedly confirming with a vacuum processing apparatus, it was found that the plastic film wound body subjected to the vacuum processing in which P was 180 Pa or less performed good running without winding deviation, which is the object of the present invention. Here, P depends on the winding condition in the slitting process, and the film residual stress due to the tension at the time of winding,
It is known that it is governed by the ease of air release, the viscosity of the air, the slipperiness of the film, and the like. Further, as a winding method for reducing the film stress, it is effective to reduce the residual stress strain of the film at low tension and to apply a high surface pressure to directly suppress the amount of air taken in. Further, a method of lowering the film stress T by lowering the strength (Young's modulus) of the plastic film itself to reduce the film stress against the expansion force of air may be used. Further reducing the temperature of the air during or after winding to reduce the air viscosity between the winding layers;
Alternatively, a method of lowering the humidity of air or the like is also effective. Naturally, the design of a plastic film with good air release is also important, and the surface design, rigidity, etc. of the plastic film are also important indicators.

As described above, in the present invention, the object of the present invention is achieved by suppressing the expansion force due to the air pressure wound in the plastic film winding body to 180 Pa or less and reducing the film stress T.

That is, the plastic film wound body of the present invention having an expansion force of 180 Pa or less is a good plastic film wound body in which entrapped air is sufficiently removed and no residual stress remains in the film. It is possible to provide a plastic film wound body that runs well without any deviation in the processing steps.

In the present invention, the film stress T and the expansion force P under vacuum can be measured by the following methods. As shown in FIG. 1, a plastic film roll 2 is fixed in a chamber 1 capable of reducing the pressure to 1 torr or less, and 15.5 N is applied to the plastic film 3 to be rewound.
The load cell 4 to which a tension of / m was applied was set via a guide roll 5 rotatably supported, and the indicated value of the load cell was recorded while evacuating from the exhaust hole 6 by a vacuum pump 7. FIG. 2 shows a typical characteristic example of the film stress T due to the expansion force of air. Here, the value T of the load cell 4 was read at the position where the equilibrium was reached, and the expansion force P due to the air pressure was obtained by the above-mentioned equation (1).

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments, but the present invention is not limited to these embodiments. The following method was used to evaluate the running property of the plastic film in the vacuum chamber.

When the degree of vacuum is 1 torr or less, the plastic film wound body 2 is unwound at a speed of 200 m / min and a tension on the unwinding side of 9.8 N / m as shown in FIG. It was wound up as a take-up roll 10. At this time, the displacement amount 11 (FIG. 4) of the plastic film 3 on the unwinding side from the glass window 8 of the chamber 1 is read by a cassette meter. In FIG. 4, the shift amount 11 is exaggerated. Good if the deviation value is less than 2mm, 2m
If it is not less than m, it is determined to be bad.

The evaluation of the vacuum running property and the measurement of the expansion force were carried out using the following standards. The size of the wound layer body used here was 1.9 μm in thickness, 315 mm in width, and 18,000 m in winding length.
Is a wound layer of a polyester film which has been biaxially stretched and heat-treated after being wound around a core having an outer diameter of 160 mm.

Hereinafter, Examples and Comparative Examples will be described. Example 1 The winding tension was linearly reduced from 24.5 to 19.6 MPa with respect to the winding diameter, and the surface pressure was reduced from 539 to 637 with respect to the winding diameter.
It was raised linearly to N / m and wound up.

Comparative Example 1 Winding tension (24.5 MPa) and surface pressure (539 N / m)
Was wound without changing the winding diameter.

Example 2 The film wound body of Comparative Example 1 was sealed in a bag in which silica gel was put and a polyethylene film was laminated with an aluminum foil, and the film wound body was sufficiently dried.

Comparative Example 2 The film wound body of Example 1 was left in a room controlled at room temperature of 40 ° C. and humidity of 90% for 24 hours.

Example 3 In the film forming process, the film had a Young's modulus of 4.7 G in the winding direction.
A film having a thickness of Pa or less was formed and wound under the conditions of Comparative Example 1.

Comparative Example 3 In the film forming process, the film had a Young's modulus of 4.9 G in the winding direction.
A film of Pa or more was formed and wound under the conditions of Comparative Example 1.

Table 1 summarizes the expansion force P and the vacuum running property of the obtained film wound body due to the air pressure involved.
It was shown to. Further, the film thickness is 0.9, 1.2, 1..
4, 1.9 μm, a film wound up in the same winding pattern as in Example 1 (Example), and a film wound up in the same winding pattern as in Comparative Example 1 (Comparative Example) ) Are shown in Table 2 (Examples 4 to 5).
7, Comparative Examples 4 to 7).

[0024]

[Table 1]

[0025]

[Table 2]

As is clear from Tables 1 and 2, when the expansion force of the film wound body is 180 Pa or less, good vacuum running properties can be obtained.

[0027]

According to the rolled plastic film of the present invention, a good running property without winding deviation in the vacuum processing step can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for measuring a film stress T.

FIG. 2 is a relationship diagram between a film stress T and a chamber decompression time.

FIG. 3 is a schematic configuration diagram of a vacuum processing apparatus.

FIG. 4 is an explanatory diagram of observation of a winding deviation amount during rewinding in a vacuum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Plastic film winding layer 3 Film 4 Load cell 5 Guide roll 6 Exhaust hole 7 Vacuum pump 8 Glass window 9 Take-up roll 10 Holding roll 11 Winding deviation

Claims (4)

[Claims] 1. A roll of plastic film which is subjected to a vacuum treatment wound in a roll having an expansion force of 180 Pa or less. 2. The plastic film has a thickness of 0.5 to 0.5.
The plastic film roll according to claim 1, which is in a range of 15 µm. 3. The plastic film roll according to claim 1, wherein the plastic film is processed by vacuum deposition. 4. The plastic film roll according to claim 1, wherein the plastic film is a polyester film.