JPH04106057A - Winding method for web - Google Patents

Abstract

PURPOSE:To reliably prevent production of wrinkles during the initial stage of winding when a web is wound by using a touch roll by effecting the web such that the press force of a touch roll is substantially reduced to zero during the initial stage of winding of the web and thereafter effecting winding in a manner that a pressure force is increased to a given value. CONSTITUTION:In a process wherein a film 1 is wound around a core 3 in a state that the core 3 pivotally supported to a bearing 5 is rotated by a drive device, the film is wound in a state to press the film 1 against a touch roll as a touch roll 2 is pressed toward the core 3 side through the working of a cylinder 4. In winding, winding is effected by means of the press force of the touch roll 2, reduced to substantially zero, until a point of time when the number of winding layers is increased to a value approximate 1/80 of the total number of winding layers available upon completion of winding of the web wound around the core, and thereafter winding is carried out in a state that a press force is increased to a given value. This time is influenced by a winding speed, a film material, a film width, and the thickness of the film. Since winding with a press force, reduced to substantially zero, for a long period reduces production of the original effect of touch roll winding, a period in which the winding is effected is reduced to a value being as low as possible.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a web winding method.

[Conventional technology]

In recent years, when it comes to winding webs, especially thin films,
The main cause is air entrainment during the winding process, which causes wrinkles inside the roll due to misalignment or tightness of the winding. This tendency has become more pronounced as webs have been wound up at higher speeds in recent years.

Therefore, in order to solve this problem, conventionally, as shown in FIG. Many winding methods have been adopted.

[Problem to be solved by the invention]

However, in this touch roll winding method,
Since a pressing force is applied to the film 1, there is a problem in that wrinkles occur at the initial stage of winding. In other words, during the initial period of film winding, it is difficult to set the film l in a completely accurate position with respect to the winding core 3, and distortion is likely to occur due to misalignment (the film is susceptible to the effects of this distortion). in a state.

Further, the pressing force of the touch roll 2 acts on this distortion, and a restricting force in the width direction due to an increase in the frictional force between the films acts, reducing the degree of freedom of the film 1, especially in the width direction. Further, the deflection of the touch roll 2 itself in the longitudinal direction acts directly on the film at the initial stage of winding. These factors are intertwined in a complicated manner, and wrinkles are likely to occur particularly in the initial stage of film winding. The wrinkles that occur at this early stage of winding are compared to wrinkles caused by air entrainment.
This has a great effect on the quality of the film, and quality problems such as sensitization (fogging) and desensitization become apparent, especially in films with coated layers in photographic light-sensitive materials.

Furthermore, these problems have become more apparent due to thinner films and higher speed winding in recent years.

Therefore, an object of the present invention is to reliably prevent wrinkles that occur at the initial stage of winding when a touch roll is used for winding.

[Means to solve the problem]

The above-mentioned problem is that in a method for winding a continuous web while pressing a touch roll, during the initial period of web winding, the web is wound with substantially zero pressing force, and then a predetermined amount of pressure is applied to the web. This can be solved by winding up with the suppressing power increased.

Further, it is preferable that the period of winding with the pressing force of the touch roll being substantially zero is a period of 1/80 or less of the total number of layers at the end of winding of the web wound around the core. .

[For production]

In the present invention, at the initial stage of winding, winding is performed with the pressing force of the touch roll being substantially zero, and thereafter, winding is performed with the pressing force increased to a predetermined pressing force.

Therefore, at the early stage of winding, when the film is easily affected by distortion of the film or deflection of the touch roll itself, the touch roll exerts almost no regulating force on the film, so that wrinkles that occur at the early stage of winding can be reliably prevented.

In addition, in order to make the most of the original effect of the touch roll winding method that prevents air entrainment, when the winding period ends with the pressing force of the touch roll being essentially zero, the original touch roll winding is performed. Since the process moves to remove the paper, it is possible to prevent the occurrence of wrinkles due to air entrainment.

[Specific structure of the invention]

The present invention will be explained in more detail below with reference to a specific example shown in FIG.

In the present invention, the above-mentioned so-called touch roll winding method is adopted in order to prevent the occurrence of wrinkles at the initial stage of winding. That is, as shown in FIG. 1, the touch roll 2 is rotated by a cylinder 4 or the like in the process of winding the film 1 onto the core 3 while rotating the core 3 supported by a bearing 5 by a drive device (not shown). While pressing the film 1 against the core 3 side, wind it up.

During winding, the pressing force of the touch roll is substantially zero until the total number of layers at the end of winding of the web wound around the core reaches 1780, and then,
Winding is performed with the pressing force increased to a predetermined level. During this period, the winding speed, film material, film width,
Although it is influenced by the film thickness, etc., winding with substantially zero pressing force for a long period of time weakens the original effect of touch roll winding, so it is preferable to shorten the time as much as possible.

Thus, at the initial stage of winding, even if there is distortion due to positional deviation during position setting, the pressing force of the touch roll 2 does not act on the film 1 and no regulating force acts on the film 1, so that no wrinkles occur.

When the pressing force of the touch roll is substantially zero, it is substantially the same as when no pressing force is applied from the viewpoint of preventing the occurrence of wrinkles, which is the objective of the present invention. The upper limit of the pressing force at which the pressing force can be considered to be substantially 0 varies depending on the various winding conditions (for example, winding speed, film thickness, film material, film width), but if the pressing force is 5 kgf.
/m or less, which is considerably lower than the predetermined pressing force.

In addition, as a method to make the pressing force substantially zero, there is also a method of separating the touch roll 2 from the core 3 so that it does not come into contact with the film 1;
When bringing the film into contact with the film 1, it is preferable to accelerate the circumferential speed of the touch roll 2 to the circumferential speed of the winding surface of the winding core 3 in advance, and then bring it into contact and press it to avoid scratches. .

Of course, it is also possible to keep the touch roll in contact with the film surface from the start of winding.
It may be set to be less than gf/m.

On the other hand, when the period in which the pressing force is essentially zero ends, the process moves to a pressing stage with a predetermined pressing force. In this case, the higher the pressing force, the better the effect of discharging the entrained air, but if the pressing force is excessively high. and film quality problems will occur.
Generally, 60 kgf/m or less is preferable.

Further, the surface material of the touch roll 2 used is preferably an elastic material in order to avoid scratches during winding.

〔Example〕

Next, the effects of the present invention will be clarified through examples.

(Example 1) Using polyethylene terephthalate films of two different thicknesses, 75 μm and 100 μm, the winding speed was changed to 60 m/win and 100 m/min, respectively. Press with a touch roll in various pressing patterns shown in Figure 2 to produce 10 rolls each, and compare the length and initial pressure area of 0 initial pressing force (number of winding layers with pressing force of 0/final total number of winding layers). The frequency of wrinkle occurrence was investigated.

Winding conditions: core diameter; φ180 mm; tension, 100 kgf/width; steady pressure of touch roll: 20 kgf/width; film width: 2100 mm; winding length; 5000 m. Note that the touch roll has a core diameter of φ100 mm.
Made of iron with 100111 elastic rubber with a hardness of 50° on the surface.
One coated with a thickness of 1 was used.

As a result, the line ■ shown in Figure 3 indicates a film thickness of 100.
The results are shown when the film was wound at a winding speed of 60 m/min using a film with a film thickness of 100 μm.
The results are shown when winding was carried out at a winding speed of 100 m/min. Also, line ■ indicates film thickness 7
The results are shown when a film with a thickness of 5 μm is used and wound at a winding speed of 60 m/min, and the line ■ shows the results when a film with a thickness of 75 μm is used and wound at a winding speed of 100 m/min. .

Incidentally, the incidence of wrinkles is proportional to the film thickness and winding speed; the thinner the film, the more likely wrinkles will occur, and the faster the winding speed, the more likely wrinkles will occur.

Therefore, from the result of line ■, the area where the pressing force of the touch roll is practically 0 is 1/80 of the total number of layers at the end of winding.
The following is sufficient to reduce the frequency of wrinkles to 0%.

(Example 2) Two types of polyethylene terephthalate films with different thicknesses, 75 μm and 100 μm, were used and the winding speed was changed to 60 m/min and 100 m/win, respectively, for 4 cases under the following conditions. Press with a touch roll in the same pressing pattern, and roll each product one by one.
0 pieces were produced and the frequency of initial wrinkles was investigated.

・A method of winding while applying a pressing force of 20 kgf/width from the start of winding to the end of winding (Comparative Example 1) ・The pressing force is applied until the 30th winding, which is 1/80 of the total number of layers at the end of winding. 0, and then winding while applying a pressing force of 20 kgf/width (Example 2) Winding conditions - Core diameter: φ180 mm - Tension: 100 kgf/width - Desired pressing force of touch roll: 20 kgf / Width/Film width; 2100 mm Rolling length: 5000 m The touch roll 2 has a core diameter of 100 m.
A material made of steel with a hardness of 50° and coated with elastic rubber having a hardness of 10 mm was used.

As a result, as shown in Table 1, in Comparative Example 1,
Winding speed 60m/m i for film thickness 100μm
When wound at a winding speed of 100 m/win, wrinkles were confirmed in 5 of the 10 films produced. Similarly, when a film with a thickness of 100 μm was wound at a winding speed of 100 m/win, wrinkles were observed in 5 of the 10 films produced. Wrinkles were confirmed on 8 of the films. For films with a thickness of 75 μm, wrinkles were observed in 10 out of 10 films regardless of the winding speed.

On the other hand, in Example 1, no wrinkles were observed in any case.

Table 1 4...Cylinder

Claims (2)

[Claims] (1) In a method of winding a continuous web while pressing a touch roll, during an initial period of web winding, winding is performed with the pressing force of the touch roll being substantially zero;
A web winding method characterized in that the web is then wound while increasing the pressing force to a predetermined pressure. (2) A claim in which the period of winding with substantially zero pressing force of the touch roll is a period of 1/80 or less of the total number of layers at the end of winding of the web wound around the core. 1. The web winding method described in 1.