JP2003145621A - Method for stretching film or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stretching a film or the like in which a production efficiency is good by a clip chain method and a maintenance is easy and which can longitudinally and laterally stretch the film. SOLUTION: The method for stretching the film or the like comprises the steps of aligning in series a pair of front stage clip chain mounting a plurality of clips oppositely via a substantially width size of the film or the like feeding in a longitudinal direction by an independent drive source and a rear stage clip chain having the same constitution as that of the front stage clip chain, sequentially supplying the film or the like to the front stage clip chain and then to the rear stage clip chain between the pair of the clip chains, and longitudinally stretching the film or the like according to V2>=V1, wherein V1 is the front stage clip chain feeding speed and V2 is the rear stage clip chain feeding speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretching method for grasping and stretching both ends of a plastic film or sheet in the width direction with clips.

[0002]

2. Description of the Related Art Conventional stretching methods for films, sheets, etc. (hereinafter referred to as films, etc.) are a longitudinal stretching method for stretching the film in the running direction, and a sequential stretching method for further stretching the longitudinally stretched film in the width direction. A simultaneous biaxial stretching method in which stretching is performed simultaneously in the longitudinal and transverse directions is well known.

Explaining each method, the longitudinal stretching method is as shown in FIG. 5, in which a film 3 or the like is longitudinally stretched between rolls 1 and 2 which rotate at speeds v1 and v2 (v2 ≧ v1). A method of forming a longitudinally stretched film or the like 4. As for the transverse stretching method, the width dimension of the film or the like 5 which has not been stretched or which has been longitudinally stretched in advance by the above-described longitudinal stretching method is set so that the vicinity of the entrance is substantially the width W of the film or the like 5 toward the back (in the right direction in the figure) as shown in FIG. A pair of clip chains 7 having a plurality of clips 6 (6a, 6b, 6c, ...) that are made larger and face each other to have a predetermined width Wn are gripped at both ends in the width direction of the film 5 by a pair of clip chains 7. 8 is a method of running in the direction of arrow d and stretching laterally.

A simultaneous biaxial stretching method for simultaneously stretching in the longitudinal and lateral directions is a link mechanism in which a plurality of clips 9a, 9b, 9c, ..., Which hold both ends in the width direction of a pair of opposed films, as shown in FIG. 7, are attached. 10 is parallel in the vicinity of the entrance, and is guided by grooves 11 and 12 that widen to a predetermined width as it goes deeper,
As shown by arrow d, the film is transferred in the film running direction by a chain (not shown). Therefore, the clips 9a, 9b, 9c
.. The pitch P between them is expanded to the pitch Pn and is stretched because it moves in the lateral direction. The pair of clips 9a, 9b, 9c facing each other ... This is a method in which a predetermined film width Wn is achieved and longitudinal and transverse stretching can be performed at one time.

[0005]

Since the conventional longitudinal stretching method described above stretches on the surface of the roll, fine scratches (scratches) can be formed on the surface of the film or the like, and particularly in recent optical films, scratches are extremely scratched. There was a drawback that I could not use it because I hate him. In the case of a resin with a high crystallization rate (eg, nylon 6), it is necessary to quench the crystallization after longitudinal stretching to suppress crystallization, and then heat again for transverse stretching, or depending on the type of resin, transverse stretching itself may occur. There was also the drawback that it would not be possible.

In the simultaneous biaxial stretching method of stretching in the longitudinal and transverse directions at the same time, since the edges of the film in the width direction are gripped by clips, there is no fear of scratches and there is a drawback that stretching cannot be performed even if the crystallization speed is high. However, the link mechanism and its control for increasing the pitch of adjacent clips for longitudinal stretching in order and changing the facing width of a pair of facing clip chains for lateral stretching have been eliminated. Not only is it complicated and expensive, but its structure is complicated, so there are many failures and its maintenance is troublesome. Moreover, not only the stretching speed is limited to about 150 m / min, but also the distance between the front and rear clips after stretching becomes large,
The film edge between the front and rear clips was greatly deformed inward, and only the central portion of the film was a product, so the yield was low and the productivity was poor.

The object of the present invention is to provide a longitudinal stretching method that can be used for optical films and the like, which is free from scratches by rolls that are present in the conventional longitudinal stretching method for films and the like, and the problem of crystallization during lateral stretching and the mechanism are complicated. There are many failures and maintenance is troublesome, and the disadvantages of slow drawing speed and poor productivity and poor yield in the width direction of the film are eliminated, and the clip chain method provides high production efficiency and easy maintenance. An object of the present invention is to provide a method for stretching a film or the like that can be longitudinally and laterally stretched.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention has a plurality of clips which are opposed to each other by an independent driving source at intervals of a substantially constant width such as a film running in the longitudinal direction. A pair of attached front-stage clip chains and a rear-stage clip chain having the same configuration as this front-stage clip chain are arranged in series, and films and the like are supplied between the front-stage clip chain and the rear-stage clip chain in order between each pair of clip chains. The speed of the front clip chain
When V1 and the traveling speed of the rear clip chain are V2, V
A film or other stretching method is characterized in that the film or the like is longitudinally stretched with 2 ≧ V1.

Further, a pair of front-stage clip chains having a plurality of clips attached to each other, which face each other with a substantially constant width dimension, such as films running in the longitudinal direction by independent driving sources, and a substantially film near the entrance. A pair of second-stage clip chains, which become gradually wider as they go deeper from the same width dimension, are arranged in series, and the film is supplied between the first-stage clip chain and then the second-stage clip chain in order between each pair of clip chains. If the traveling speed of the front clip chain is V1 and the traveling speed of the rear clip chain is V2, V2 ≧ V1
As a method for stretching a film or the like, the film or the like is longitudinally stretched, and the film or the like is stretched laterally by a rear clip chain.

As a result, it becomes possible to perform longitudinal stretching and transverse stretching of a film or the like which has high production efficiency and is easy to maintain.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. The longitudinal stretching device 20 includes a pair of clip chains 21a and 21b facing each other with a film width W, which is a front clip chain 21.
Similarly, a rear clip chain 22 including another pair of clip chains 22a and 22b facing each other with a film width W is arranged in series. 1
Pair of clip chains 21a and 21b
Are each a plurality of clips 23 (23a, 23b, 23c
……) [Explain only one side of a pair] is attached,
The film 24 is gripped at both ends in the width direction, and speed is applied in the direction of the arrow through the sprocket 26 by a drive source (not shown).
It is moving at V1.

The other pair of clip chains 22a and 22b respectively include a plurality of clips 25 (25
a, 25b, 25c ...) are attached to the film 24
Is gripped at both ends in the width direction, and is moved at a speed V2 in the arrow direction via the sprocket 27 by a drive source (not shown). Here, if the speed V1 and the speed V2 are V2 ≧ V1, the pre-stage clip chain 21 and the post-stage clip chain 2 are made to pass by passing the film 24 through the pre-stage clip chain 21 and the post-stage clip chain 22.
Between the two, the film 24 is stretched in the running direction (longitudinal direction) to become the longitudinally stretched film 28.

As described above, since the longitudinally stretched film 27 is not stretched by a roll as in the conventional method, scratches do not occur and it can be used as a recent optical film.

Next, another embodiment of the present invention will be described with reference to FIGS. The longitudinal / horizontal stretching device 30 includes a front clip chain 31 including a pair of clip chains 31a and 31b facing each other with a film width W, and a width gradually increasing from a width of the film near the entrance to a predetermined width as it goes deeper. The other clip chain 32a and the clip chain 32b, which are opposite to each other, are arranged in series.

The pair of clip chains 31a and 31b respectively include a plurality of clips 33a and 33a.
b, 33c ... Are attached, the film 34 is gripped at both ends in the width direction, and is moved at a speed V1 in the arrow direction via a sprocket 35 by a drive source (not shown).

The other pair of clip chains 32a and 32b includes a plurality of clips 36a and 3a, respectively.
6b, 36c, etc. are attached, and both ends of the film 34 in the width direction are gripped by the film width dimension W in the vicinity of the entrance, and the width is gradually widened to a predetermined width dimension Wn as it goes deeper ( It is configured to be laterally stretched) and is moved at a speed V2 in the arrow direction via a sprocket 37 by a drive source (not shown).

Here, the speed V1 and the speed V2 are V2 ≧ V1
In this case, the film 34 is longitudinally stretched between the front clip chain 31 and the rear clip chain 32 by passing the film 34 through the front clip chain 31 and the rear clip chain 32, which are arranged in series. Film 38, which is then laterally stretched to a predetermined width Wn and biaxially stretched in the longitudinal and transverse directions.

As described above, this device is capable of biaxial stretching in the longitudinal and transverse directions without the occurrence of scratches, and the pitches of adjacent clips, which are present in the conventional simultaneous biaxial stretching method, are sequentially increased to face each other. There is no complicated link mechanism for changing the facing width of the pair of clip chains, so the film take-up speed is up to 450 m / min, productivity is improved, and the structure is simple and there are few failures.
It has become easier to maintain.

[0019]

As described above, in the present invention, there are the drawbacks that the film or the like which was initially fried by the longitudinal stretching method could not be used for optics due to the scratches by the rolls, the crystallization problem and the mechanism of the lateral stretching method. It is complicated, has many failures, is troublesome to maintain, and eliminates the disadvantages of slow drawing speed and poor productivity.The clip chain method allows for efficient production and easy maintenance, such as films that can be longitudinally and horizontally stretched. It became a stretching method.

[Brief description of drawings]

FIG. 1 is an explanatory view of a longitudinal stretching method showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing an embodiment of the present invention, in which “a”
FIG.

FIG. 3 is an explanatory diagram of a biaxial stretching method for performing longitudinal and transverse stretching according to another embodiment of the present invention.

FIG. 4 is an explanatory view of a biaxial stretching method in which longitudinal and transverse stretching is performed according to another embodiment of the present invention, and is a detailed view of “B” part.

FIG. 5 is a diagram illustrating a conventional longitudinal stretching method using rolls.

FIG. 6 is an explanatory view of a lateral stretching method using a conventional clip chain.

FIG. 7: Stretching 2 vertically and horizontally by a conventional clip chain
It is explanatory drawing of the axial stretching method.

[Explanation of symbols] 20 Vertical stretching device 21, 31 Front clip chain 22, 32 Rear clip chain 23, 25, 33, 36 clips 24, 34 film 26, 27, 35, 37 sprockets 28, 38 longitudinally stretched film 30 Vertical and horizontal stretching device 39 Biaxially stretched film

Claims (2)

[Claims] 1. A pair of front-stage clip chains, each having a plurality of clips attached thereto, which face each other with a substantially constant width dimension of films or the like running in the longitudinal direction by independent drive sources, and the front-stage clip chains. The second stage clip chains having the same structure as the above are arranged in series, and the film and the like are supplied between the first stage clip chain and then the second stage clip chain between each pair of clip chains. When traveling speed V2,
A method for stretching a film or the like, which comprises longitudinally stretching the film or the like with V2 ≧ V1. 2. A pair of front-stage clip chains having a plurality of clips attached to each other, which are opposed to each other by an independent drive source with a substantially constant width dimension of the film or the like traveling in the longitudinal direction, and a pair of front-stage clip chains. A pair of second-stage clip chains that gradually become wider as they go deeper from the width dimension of the film, etc. are arranged in series, and the film and the like are placed between the first-stage clip chain and the second-stage clip chain in that order. V2 ≧ V1 when the supply speed is V1 and the travel speed of the rear clip chain is V2
The method for stretching a film or the like is characterized in that the film or the like is longitudinally stretched and the film is laterally stretched by a rear clip chain.