JP2003236927A - Simultaneous biaxial tenter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simultaneous biaxial tenter capable of setting a plurality of longitudinal draw ratios by low cost constitution. <P>SOLUTION: Both ends of a film are fixed by a plurality of clip mechanisms 10 arranged in a row in a feed direction, and the interval between a plurality of the clip mechanisms 10 is expanded and contracted using pantograph structures 12-14 to perform longitudinal stretching. A plurality of longitudinal draw ratios are obtained by freely changing the grasping and release positions of the clip mechanisms 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretching device used for producing a film or the like, and more particularly to a simultaneous biaxial tenter capable of varying a stretching ratio.

[0002]

2. Description of the Related Art In addition to increasing strength during film production,
In order to obtain a film having an appropriate thickness, it is customary to carry out stretching. As for the stretching, there are a method of stretching in the transport direction with a roll while transporting, and a method of stretching in the direction orthogonal to the transport direction with a tenter. In addition, there is a method called a simultaneous biaxial tenter in which a special tenter is used to simultaneously stretch in the conveying direction and the orthogonal direction.
The simultaneous biaxial tenter is used during the production of films of nylon, PET, polyolefin, etc. In such a simultaneous biaxial stretching tenter, a pantograph or a screw is usually used as a clip mechanism for fixing the film at both ends thereof and for carrying and stretching.

However, since the clip mechanism in the simultaneous biaxial tenter has a complicated structure, the transverse stretching within the moving range of the rail is provided by providing a means for varying the rail interval with which the clip mechanism follows the transverse stretching ratio of the film. Although the degree of freedom in magnification can be obtained, there is a problem in that the longitudinal stretching ratio must be fixed.

A linear motor tenter has been introduced in recent years in order to make this longitudinal stretching ratio freely (for example, Katsuya Ito,
"Technical trends of flat film stretch molding", plastic age, P107, Aug 2000), cost increase of manufacturing equipment is inevitable, and introduction is not progressing.

[0005]

SUMMARY OF THE INVENTION The present invention was created in view of the above problems of the prior art, and provides a coaxial biaxial tenter capable of setting a plurality of longitudinal stretching ratios with a low cost structure. It is to be.

[0006]

In order to solve the above problems, the present invention provides the following simultaneous two-axis tenter.
That is, a tenter capable of simultaneously biaxially stretching a film while it is being stretched, and fixing both ends of the film by a plurality of fixing devices arranged in a line in the feeding direction, and fixing the gap between the fixing devices with a pantograph structure. In the configuration in which stretching is performed to perform stretching in the longitudinal direction, the releasing position of stretching stress can be freely changed. The method of releasing the stretching stress is arbitrary, but for example, the film may be slit.

In the simultaneous biaxial tenter, the fixing position of the film by the fixing device can be freely changed. With this configuration, it is possible to obtain a desired draw ratio by adjusting the disposition position of the fixing device.

In the structure in which the fixing device holds the film, the fixing device is provided with a fixing device operating member for applying an external force to the fixing member to start or release the holding at least at the start or the end of the holding. The container operation member may be installed at an arbitrary site during transportation.

In the simultaneous biaxial tenter, one or more shrinkage suppressors may be provided. The shrinkage suppressor includes a pair of rollers for holding the film after fixing by the fixing device in the vicinity of both ends thereof, and the rollers hold the film to suppress the shrinkage of the film. Thereby, the optimal draw ratio can be obtained.

The shrinkage suppressor is configured to be retractable before the stretching process, and after the stretching process is started, a transfer means is provided which is capable of transporting the retracted position to a position most suitable for suppressing the shrinkage. May be.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings. According to the present invention, it is within the design longitudinal stretching ratio range, but without replacing the pantograph, rail, etc.
A coaxial biaxial tenter capable of achieving a desired longitudinal stretching ratio can be provided. The embodiment of the present invention can be arbitrarily modified and is limited to the following.

FIG. 1 is a plan view showing an example of a simultaneous biaxial tenter (hereinafter referred to as tenter) according to the present invention. In this embodiment, a PET film is produced by using a tenter having a design draw ratio of 7 × 7 and two kinds of draw ratios of 7 × 7 and 5 × 5. The material of the film is arbitrary and may be nylon-based, polyolefin-based or the like. The unstretched film (1) enters the tenter in the direction of the arrow in the figure, and is conveyed while being gripped at both ends by the conveying mechanisms (2) and (3) arranged on the left and right of the tenter.

FIG. 2 is a plan view illustrating a clip mechanism of the transport mechanisms (2) and (3), FIG. 3 is a front view of the same, and FIG. 4 is a side view showing a gripping / releasing state of each clip mechanism. Indicates. In FIG. 2, each clip mechanism (10) (10)
(10) (10) are pantographs (11) (12) (1
4) connected by an end (1) of the pantograph (12)
2a) is fitted in the groove (13a) of the clip mechanism crosspiece (13).

FIG. 2 shows a state in which the pantographs (11) and (12) are expanded. When the pantographs (11) and (12) are contracted, the end portion (12a) slides in the groove (13a), and the pantographs (11) (1).
Both 2) are substantially parallel to the cross section (13), and the pantograph (14) is refracted at the connection section (14a) with the adjacent pantograph (14) and is substantially parallel to the cross section (13).

A large number of clip mechanisms (10) connected by such pantographs are very continuous and constitute the transport mechanisms (2) and (3) in FIG. As shown in FIGS. 3 and 4, wheels (15) and (15) are provided on the bottom of the cross section (13) of the clip mechanism, and the rails (4), (4), (5), and (5) shown in FIG. Each clip mechanism (10) is transferred by rotating it upward. Especially the transport mechanism (2)
Protrusions (16) (16) near position A in (3)
A guide (not shown) that narrows the space between the rails is laid between the rails to contract the pantograph, while the guide that widens the space between the protrusions (16) (16) near the position B expands the pantograph.

Further, FIG. 4A shows a state in which the gripping portion 17 for fixing the film is gripped, and FIG. 4A shows a released state. The gripping part (17) is composed of an iron disk body on both the upper surface (17a) and the lower surface (17b), and since it is magnetized, the film can be strongly fixed in the gripping state.

The upper surface (17a) is connected to the chuck (19) by the link portion (18). While the chuck is tilted in the gripping state as shown in (a), the chuck (19) is erected in the released state and the upper surface ( At the same time, 17a) moves up and moves to the pantograph side, and withdraws from the magnetic attraction. As described above, the clip mechanism (10) that effectively holds and releases the chuck (19) by inverting it is configured.

The transport mechanisms (2) and (3) in the present embodiment have the above-described structure to grip both ends of the film (1) at the position A and transport the film (1) in accordance with the transport of the clip mechanism (10). And at position B the rail (4)
The film (1) is stretched in the lateral direction by widening the gap between the (4) and the rails (5) and (5), while being stretched in the longitudinal direction in accordance with the expansion of the pantographs (11), (12) and (13). To be done. This is the configuration of simultaneous biaxial stretching.

In the conventional simultaneous biaxial stretching, gripping by the clip mechanism continues to the end portion (corresponding to position D) of the transport mechanism, and a chuck opening device is provided at the end portion.
As the chuck is opened, the film shrinks due to stress.
The dotted line (1 ′) in FIG. 1 shows the shape of the film in the conventional structure.

As described above, in the conventional simultaneous biaxial tenter, the stretching ratio of the film is fixed, and even if the lateral stretching ratio is changed by changing the rail interval, the longitudinal stretching depends on the interval of the clip mechanism. The magnification was unchanged. Therefore, the tenter structure must be changed in order to cope with a plurality of draw ratios, and a very high cost and flexible manufacturing process cannot be realized.

In the present invention, the chuck opener (2
0) is created in which a tenter capable of being arranged at any position is created, and a filter having a plurality of draw ratios is manufactured. The chuck opener (20) is made of a resin having an approximately three-sided pyramid shape, and one side surface thereof abuts the pantograph side of the chuck (19) to gradually erect the chuck (19) to hold the gripper (1
Release 7). The state of FIG. 3a shows a state in which the chuck opening device (20) has started to contact, and the state of b shows a state in which the chuck is upright and the grip is released. The state of b in FIG.
It is a state of the clip mechanism (10) at the position C in the middle.

This tenter having a design draw ratio of 7 × 7 is
In the conventional configuration, after passing the position D, it is contracted and adjusted so as to reach the design magnification. However, according to this configuration,
Since the gripping can be finished at any position in the transport mechanisms (2) and (3), for example, when a stretching ratio of 5 × 5 is desired, the clip mechanism (10) is released at the position C and stress is increased. The desired shrinkage of 5 × 5 is obtained by shrinking with.

Similarly, according to this structure, it is possible to realize an arbitrary draw ratio simply by appropriately changing the arrangement position of the chuck opening device (20). The chuck opener (20) is arranged on the basis of the desired longitudinal stretching ratio, and the distance between the rails (4), (4) and (5) (5) is adjusted in order to obtain the desired lateral stretching ratio. The change in the rail interval can be easily dealt with by moving the transport mechanisms (2) and (3).

The arrangement position of the chuck opener (20) may be selected according to the material of the film in consideration of shrinkage stress in advance and selected for each longitudinal stretching ratio. That is, when PET is used at a draw ratio of 3 to 10 times suitable for using the tenter of the present invention,
The chuck opener position for obtaining a draw ratio of 3 times, the position of 4 times, etc., can be specified in advance, and a desired draw ratio can be realized immediately.

In the above embodiment, the clip mechanism (10) is used as the fixing device and the stretching stress is released by releasing the grip. However, in the present invention, the stretching stress is not always released depending on the presence or absence of the fixing by the fixing device. Alternatively, for example, the film may be slit and released. When slitting the film, it is preferable to dispose a member for preventing the propagation, for example, a roller, immediately before the cutter so that the slit does not propagate to the upstream side of the conveyance.

Further, in the present invention, the shrinkage suppressor (30) shown in FIG. 5 may be provided to realize a more accurate stretching ratio. The shrinkage suppressor (30) is a pinch guider (31) consisting of two rollers that sandwich the film.
And a support base (32) for pivotally supporting the pinch guider (31)
A transfer part (33) for moving the support base (32) substantially parallel to the film transport direction by screw feeding, and a guide rail (34) for holding the support base (32) during transfer.

The guide rail (34) is fixed to the angle (21) provided on the transport mechanism (2) by the pin (22), and slightly inward as the film (1) shrinks, as shown in FIG. Install it at an angle. Plural pairs of pin guiders (31) are arranged at appropriate intervals with respect to the screws of the transfer section (33) at positions facing each other on the transport mechanism (2) side and the (3) side.

The two rollers of the pinch guider (31) press against each other and sandwich the film (1) between them. Since the film (1) is being transported, the roller is restrained from contracting in the width direction of the film (1) while rotating. At this time, the pinch guider (31) acts so as to stretch the film (1) by inclining the open end side so as to be the upstream side in the transport direction of the film (1), and the shrinkage can be suppressed more effectively.

Here, the guide rail (34) can be appropriately set in the present invention, but it is desirable that the guide rail (34) has an inclination of approximately 5 to 20 degrees inward from the transport direction of the film, and an angle smaller than that. The film cannot follow the shrinkage of the film, and at a larger angle, the shrinkage is too large, so there is a problem in the release position of the grip or the position of the angle (21).

Pinch guide (31) and support (32)
The arrangement interval can be appropriately set depending on the characteristics of the material, the temperature, etc., but it is generally preferable to provide the interval of about 50 cm to 100 cm from the time when the grip is released.
More preferably, the distance is about 50 cm near the release point, and the distance is about 100 cm near the end of the transport mechanism. This is because the shrinkage of the film is severe near the release point and a lot of support is required, while the shrinkage is suppressed near the end part, and the main purpose is to stably convey the film. is there. In particular, since the pinch guider has a function of stretching the film, it is likely to cause distortion and is not preferably arranged more than necessary.

The tenter according to the present invention has the above-mentioned structure, and a specific operation example is shown below. For example, when it is desired to draw at a draw ratio of 5 × 5, first draw at a design ratio (7 × 7 in this case), and then pass line is performed. Next, the chuck opener (20) is made to work, and both ends of the film (1) that has come out are sandwiched by the pinch guiders (31), and the transfer section (33) is operated, so that the pinch guiders (31) are placed in the tenter. Transfer in sequence.

When the pinch guider (31) is transferred in this way, the shrinkage of the film is suppressed, so the inclination of the guide rail (34) is adjusted according to the amount of suppression. Through the above steps, the desired 5 × 5 film is transferred to the transport mechanism (2) (3).
Is discharged from the end of the.

A pinch guider is used as a fixture,
The film is conveyed and stretched by grasping and releasing the pinch guider, but the present invention is not limited to the above, and the film can be fixed, and the stretching ratio can be changed by changing the position of the fixing device in the tenter. If so, it is included in the present invention. The structure of the fixing device and the like can be arbitrarily changed.

[0034]

As described above, the simultaneous biaxial tenter of the present invention is provided with the above-mentioned structure, so that it is possible to realize a variable draw ratio, which is difficult with the conventional simultaneous biaxial tenter. That is, it is possible to obtain a desired longitudinal stretching ratio within the design longitudinal stretching ratio range by only changing the stretching stress releasing position and without changing the pantograph or the rail at high cost. This contributes to the cost reduction of the manufacturing system and
Various films can be manufactured quickly.

In particular, the structure for changing the position of the fixing device for applying / releasing the stretching stress can adopt the above-mentioned structure using the existing fixing device, so that the cost can be reduced and the introduction is extremely easy. .

Further, by providing a shrinkage suppressor in the present invention, unstable shrinkage of the film is suppressed, which contributes to accurate film production. A film with high precision brings about a high added value of the product and can improve the production efficiency.

[Brief description of drawings]

FIG. 1 is a plan view of a simultaneous biaxial tenter according to the present invention.

FIG. 2 is a plan view illustrating a clip mechanism.

FIG. 3 is a front view of the same.

FIG. 4 is a side view showing a gripping / releasing state of each clip mechanism.

FIG. 5 is a perspective explanatory view of a contraction suppressor.

[Explanation of symbols] Position of clip mechanism Position of clip mechanism 10 clip mechanism 12 Pantograph 13 cross section 14 Pantograph 14a same, connection part 15 wheels 20 Chuck opener 21 angle 22 screws 31 pinch guide 32 support 33 Transfer Department 34 Guide rail

Claims (5)

[Claims] 1. A tenter capable of carrying a film while stretching and carrying out simultaneous biaxial stretching, wherein both ends of the film are fixed by a plurality of fixing devices arranged in a line in the feeding direction, and the distance between the fixing devices is fixed. A simultaneous biaxial tenter wherein the releasing position of the stretching stress can be freely changed in a configuration in which stretching is performed in the longitudinal direction by expanding and contracting using a pantograph structure. 2. The simultaneous biaxial tenter according to claim 1, wherein in the simultaneous biaxial tenter, the fixing position of the film by the fixing device can be freely changed. 3. A structure for holding a film by the fixing device, further comprising a fixing device operating member for applying an external force to the fixing member to start or release the holding at least at the start or end of the holding. The simultaneous 2 according to claim 2, wherein the fixing device operating member can be installed at an arbitrary site during transportation.
Axis tenter. 4. A contraction suppressor in the simultaneous biaxial tenter, comprising a pair of rollers capable of suppressing the contraction of the film, which holds the film after being fixed by the fixing device in the vicinity of both ends thereof. 4. The simultaneous biaxial tenter according to claim 1, wherein one or a plurality of units are arranged. 5. The contraction suppressor is configured to be retractable before the stretching process, and after the stretching process is started, a transfer means capable of transferring the retracted position from the storage position to an optimum position for suppressing the contraction. The simultaneous biaxial tenter according to claim 4, which is provided.