JP3456872B2 - Winding method of plastic film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for winding a plastic film, and more particularly, a contact pressure roller installed in parallel with a winding film roll is brought into close contact with the film while pressing the film to wind the film into a roll shape. The present invention relates to a winding method.

[0002]

2. Description of the Related Art Since a plastic film is required to have various processability such as coating, printing and laminating, a film roll is required to have a good winding shape without wrinkles and an appropriate winding hardness. The wrinkles that occur on the film roll are usually likely to occur at the center of the roll, and even if there are no wrinkles immediately after winding, they may occur over time or wrinkles may grow. Conventionally, as a method of winding a plastic film into a roll, the pressure of the contact roller is controlled to be wound based on empirical knowledge, but the appearance quality of the film roll varies depending on the skill of the operator. Moreover, wrinkles are liable to occur particularly when the width of the film is wide or when the film is wound at a high speed, and it has been necessary to reduce the winding speed at the sacrifice of productivity.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems and to provide a method capable of stably producing a plastic film roll having a good winding shape without wrinkles at a high speed.

[0004]

Means for Solving the Problems The present invention can solve the above-mentioned problems by winding the film while suppressing the thickness variation of the air layer between the film and the pressure roller in the film width direction to a certain value or less. The inventors have found what can be done and have reached the present invention. That is, the present invention is a winding device that presses a contact roller against a take-up roll to wind a film in a roll shape while applying surface pressure, in a center portion in the film width direction between the film and the contact roller. When the thickness of the air layer is t _c and the thickness of the air layer between the film and the pressure roller at the edge in the width direction of the film is t _s , take up under the condition of t _c −t _s ≦ 200 μm. And

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Generally, in a winding method using a contact pressure roller, a film passing over the contact pressure roller is contacted with the film under the influence of an accompanying air flow introduced between the contact pressure roller and the film. It is wound up slightly floating on the roller. This phenomenon becomes noticeable when winding a wide film or at high speed. On this occasion,
At the edges of the film in the width direction, the air taken in easily escapes, but the air taken in at the center is difficult to escape,
A phenomenon occurs in which the film floats in an arcuate shape on the contact roller, which easily causes wrinkles near the center of the winding film roll.

In the present invention, as shown in FIG. 1, in the winding device for pressing the contact pressure roller 3 against the winding film roll 4 to wind the film 1 into a roll while applying a surface pressure, the film width Thickness (t _c ) of the air layer between the film 1 and the pressure roller 3 at the center in the width direction, and thickness (t _s ) of the air layer between the film 1 and the pressure roller 3 at the edge in the width direction of the film. It is necessary to wind it under the condition that the difference of is less than 200 μm.

In order to suppress the difference between t _c and t _s to be not more than 200 μm by positively letting the entrained air brought between the pressure contact roller and the film, the surface roughness of the pressure contact roller, the film It is necessary to adjust the take-up tension, etc., to a value within an appropriate range.

That is, in the present invention, it is necessary to adjust the maximum surface roughness (SRmax) of the pressure contact roller to 6 to 10 μm. If SRmax is less than 6 μm, it is difficult for the accompanying air introduced between the pressure roller and the film to escape, and if it is greater than 10 μm, the unevenness of the pressure roller is transferred to the film, which is not preferable. As a preferable material for the pressure contact roller, for example, a hard chrome-plated surface having a satin finish is used.

The film winding tension (F) is an important factor closely related to the phenomenon that the film floats in a bow shape on the pressure roller, and is preferably 3 to 20 kgf / m. If F is less than 3 kgf / m, the film may float on the contact roller and may be wrinkled, causing folding and wrinkling. If F is greater than 20 kgf / m, stress remains in the wound film roll,
The film gradually shrinks and wrinkles easily occur over time.

In the present invention, the friction coefficient of the surface of the pressure contact roller with respect to the plastic film is preferably 0.5 or less. If the friction coefficient is larger than 0.5, the thickness of the air layer on the contact roller tends to fluctuate, and (t _c −
It becomes difficult to wind up with t _s ) kept below 200 μm.

Further, in the present invention, it is preferable that the holding angle (θ) of the film on the contact roller is 5 to 180 °. It is preferable to make the included angle as small as possible because the accompanying air can easily escape. Above 180 °,
The placement of the film roll is mechanically difficult and unrealistic.

The thickness of the plastic film used in the present invention is not particularly limited, but is usually 6 to 25.
It is effective when used for a film having a thickness of .mu.m, and is particularly effective for a thin product having a thickness of 9 to 12 .mu.m, which is likely to cause wrinkles. Also,
There is no particular limitation on the width of the film, and it is particularly effective when applied to a wide film of 800 mm or more.

There is no particular limitation on the film to which the method of the present invention can be applied.
Examples of the film include polyolefin films. Also,
These films may be subjected to various surface treatments such as corona treatment and easy adhesion coating.

[0014]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 1 A carbon fiber reinforced plastic (CFRP) having a hard chromium plating on its surface was roughened to have an SRmax of 7 μm, and a contact pressure roller was used to make the thickness 12 μm and the width 1000 m.
A polyethylene terephthalate film having a length of 12000 m was wound under the conditions of a winding tension of 5 kgf / m, a winding contact pressure of 40 kgf / m, and a winding speed of 400 m / min. The friction coefficient of the contact pressure roll was 0.3, and the holding angle of the film was 120 °. The thickness of the air layer between the film being wound and the pressure roller was measured using an ultrasonic displacement sensor (manufactured by Keyence Corp.), t _c was 210 μm and t _s was 50 μm. The film roll obtained had no wrinkles at all and had a good winding appearance.

Example 2 A contact roller made of rubber having a friction coefficient of 0.4 was used, and the winding speed was changed.
A film roll was wound in the same manner as in Example 1 except that the speed was 240 m / min. The thickness of the air layer between the film being wound and the pressure contact roller was t _c of 200 μm and t _s of 50 μm. The film roll obtained had no wrinkles at all and had a good winding appearance.

Comparative Example 1 A film roll was wound in the same manner as in Example 1 except that a pressure roller (SRmax 7 μm) having a mirror-finished surface was used. The thickness of the air layer between the film being wound and the contact roller was 350 μm for t _{c and} 50 μm for t _s . The obtained film roll had vertical stripe-shaped wrinkles at the center.

[0018]

According to the present invention, in the contact pressure roller winding system, the film roll on the contact pressure roller is prevented from being lifted up so that a film roll having a good winding shape without wrinkles can be stabilized. It can be produced at high speed.

[Brief description of drawings]

FIG. 1 is a side view of an example of a winding device for carrying out the method of the present invention.

[Explanation of symbols]

1 film 2 winding core 3 Contact roller 4 Winding film roll 5 Ultrasonic displacement sensor 6 Pressing device

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 18/26 B65H 18/28

Claims (5)

(57) [Claims] 1. A winding device for pressing a contact roller against a take-up roll to wind a film in a roll shape while applying a surface pressure, wherein air between the film and the contact roller at a central portion in the width direction of the film. When the layer thickness is t _c , and the thickness of the air layer between the film and the pressure roller at the edge in the film width direction is t _s , the film is wound under the condition of t _c −t _s ≦ 200 μm. Winding method for plastic film. 2. The maximum height of surface roughness of the contact roller (SR
The winding method according to claim 1, wherein max) is 6 to 10 µm. 3. The winding method according to claim 1, wherein the friction coefficient of the surface of the pressure roller against the film is 0.5 or less. 4. The wrapping angle (θ) of the film on the pressure roller
Is 5 to 180 °. The winding method according to claim 1. 5. The winding method according to claim 1, wherein the film tension (F) at the time of winding the film is 3 to 20 kgf / m.