JPH0118347Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a stretching device for stretching various film-like or web-like materials such as plastic films, mesh webs, and horizontally parallel bodies of thread-like materials.

Stretching is a technology that improves the properties of plastic films, such as strength, transparency, and gas barrier properties, thereby increasing added value and enhancing performance. Conventionally, as a stretching device used for this type of processing,
In general, two methods are used: the clip tenter method, in which both sides of the flat film are held with clips, etc., and stretched uniaxially in the width direction while being fed in the longitudinal direction, and the other is the clip tenter method, in which expansion force is applied from inside to the tubular film, etc. A tubular inflation method is used in which the film is stretched in both the longitudinal and lateral directions at the same time. However, in the former method, the heating furnace, clip chain running mechanism, and other equipment are large-scale and expensive, while in the latter method, although the equipment cost is relatively low, it is difficult to control the stretching, and the stretching ratio and film thickness are difficult to control. There were disadvantages such as the tendency to cause variations in the quality of the stretched product and the difficulty in obtaining a high-quality stretched product.

Recently, a device that enables high-precision stretching with a simple structure has been developed, which includes a pair of disks arranged at a predetermined distance on substantially the same plane and rotating in opposite directions, and a rotation direction of the outer periphery of both disks. The material to be stretched is moved along each of the disks by means of gripping and moving the material to be stretched over a roughly semicircular range that diverges toward each other along the periphery of each disk, with both sides of the material being attached to the periphery of each disk. An apparatus has been developed in which the stretched material is sent in a widening direction in the direction of rotation, and the stretched material is taken out to the outside via a take-out turn roll and a take-off nip roll. By the way, in this device, the material to be stretched is stretched while being fed along the circular arc-shaped rotational path, so that the material contracts in the width direction after stretching, and the widthwise central part of the material shrinks on both sides. There was a problem that uneven stretching tends to remain where the thickness is thicker than in the vicinity of the area. As a countermeasure to this problem, the area between the take-out turn roll and the take-off nip roll is equipped with a means for heating the stretched material and a width regulating means such as a plurality of adjacent rolls, thereby controlling the width of the stretched material. Although some proposals have been made to achieve uniformity, in this case, it is difficult to avoid shrinkage of the stretched material in the section from the point where the stretched material is taken out of both stretching disks until it reaches the width regulating means.
Problems such as insufficient reliability of the stretching uniformity effect remained.

In view of these circumstances, the present invention ensures uniform stretching in a type of device that uses a pair of stretching disks to spread the material to be stretched over a roughly semi-circumferential range of the outer periphery. The object of the present invention is to provide an apparatus for stretching plastic films, etc., which can easily carry out the stretching process and produce high-quality stretched products.

That is, in the device of the present invention, a pair of stretching disks are arranged in the heating area of the material to be stretched so as to rotate in opposite directions to each other at a predetermined interval in the left and right directions in substantially the same plane, and the periphery of both the stretching disks is While holding both sides of the material to be stretched in a state in which they are attached to the periphery of each stretching disc over a stretching range of approximately a semi-circumference that diverges from each other along the direction of rotation of both discs, By providing stretching gripping means that move with the rotation of the stretching disk, a stretching mechanism is constructed that sends the material to be stretched to the end and stretches it, and the gripping means are arranged substantially parallel to each other and synchronized in a predetermined direction. A pair of rotating disks for uniform stretching are arranged close to the end positions of the stretching range of each disk for stretching, and substantially perpendicular to each of the disks for stretching, and a pair of endless belts for uniform stretching, respectively. At a point where the stretching disk and the stretching uniformity disk are close to each other, the belt is transferred from the stretching disk to the stretching uniformity disk, and is passed over each stretching disk, each stretching uniformity disk, and the guide pulley. Each belt transfers both sides of the stretched material from each stretching disk to each stretching uniformity disk, and the peripheral surface of each disk and each belt are transferred over a predetermined range of the stretching uniformity disk. The device is characterized in that it is configured so that it can be moved while being held in between.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3, 1 and 1' are a pair of stretching disks, 2 and 2' are stretching uniformity disks, 3,
Reference numeral 3' denotes a pair of endless stretching uniformity belts, which are arranged within the heating chamber 4. The inside of the heating chamber 4 is heated to an appropriate temperature using heated steam, hot air, hot water, etc., and the raw film inlet 4a at the upper end of the heating chamber 4 is heated.
A feeding nip roll 5 is arranged nearby.

Both of the stretching disks 1 and 1' are arranged at a predetermined interval on the left and right sides on substantially the same plane.
0 and 10', and are interlocked and connected to each other via gears etc. so as to rotate in opposite directions as shown by arrows A and A' in the figure. connected to the drive unit.
Each of the stretching disks 1 and 1' has a plurality of gripping tools 11 as stretching gripping means facing the back surface of the front peripheral edge of the disks 1 and 1', as will be described in detail later.
... and a pneumatic gripping device operating mechanism, and the both sides of the film to be supplied between gripping starting points A and A' at the inner ends of both discs 1 and 1' are The disks 1 and 1' are gripped and fed over a substantially semicircular area on the lower half side of the disks 1 and 1'. Further, both the stretching uniformity disks 2 and 2' face each other substantially parallel to each other,
Moreover, it is arranged close to the outer end of each stretching disc 1, 1' and substantially perpendicular to each stretching disc 1, 1', and is connected to fixed walls on both sides of the heating chamber 4 via rotating shafts 20, 20'. It is connected to a drive device (not shown) so as to rotate in the directions indicated by arrows ``b'' and ``b'' in the figure.

Further, each of the stretching uniformity belts 3, 3' has respective stretching discs 1, 1', respective stretching uniformity discs 2, 2', guide pulleys 31, 32, and 31', 32'. As shown in the diagram, it is stretched across the entire length of the building. That is, for each stretching disk 1, 1', a belt is attached to the outer periphery of the stretching disk 1, 1' over a predetermined range along the rotation direction from the vicinity of its upper end to the vicinity of points B, B' near the stretching uniformity disks 2, 2'. 3 and 3' are engaged, and the belts 3 and 3' are transferred from the stretching discs 1 and 1' to the stretching uniformity discs 2 and 2' at the proximal points B and B', and each stretching uniformity disc 2 , 2', the disk 2,
Belts 3, 3' are engaged with the outer periphery over a predetermined range in the rotational direction up to near the lower end of belt 2'. In this state, the belts 3, 3' are stretched and each disc 1,
The guide pulleys 31, 32 and 31', 3
2' is located. It is desirable that one of the left and right guide pulleys 31, 31' be a tensioner so that the tension of the belts 3, 3' can be adjusted appropriately.

Also, predetermined positions in the lower front portions of the stretching uniformity disks 2, 2' are designated as film take-out points C, C', and cutters 6, 6' cut both sides of the film at these film take-out points C, C'. At the same time, a turn roll 7 for take-out is arranged below the film take-out points C and C', and a nip roll 8 for take-off is arranged in front of the turn roll 7. The film is taken out to the outside. In addition, 9 is the cutter 6,
This is a nip roll for taking off both sides of the film cut at 6'.

4 to 6 show specific structures of the stretching mechanism and the stretching uniformity mechanism. In these figures, only the stretching disk 1 and the stretching uniformity disk 2 on one side are shown, but the disks 1' and 2' on the other side are similarly constructed. In these figures, the outer rim part of the stretching disk 1 is formed in a substantially U-shaped cross section with a recess 1a opening on the outer periphery over the entire circumference, and the back surface of the front edge is the gripping surface 1b, and the rear edge The holding portion 1c is the holding portion 1c. This holding part 1c
, a large number of gripping tools 11 are arranged at regular intervals in the circumferential direction.
are held movably in the axial direction of the stretching disk 1, and the head 11a of each gripper 11 is in the recess 1a.
It faces the gripping surface 1b inside. Inside the holding part 1c, a pneumatic cylinder part 12 is formed separately for each gripping tool 11, and in each cylinder part 12, a shaft part 11b of the gripping tool 11 is formed.
An air distributor is equipped with a piston 13 connected to a piston 13 and a spring 14 that biases the piston 13 backward, and supplies and discharges compressed air to and from each cylinder portion 12 through an air supply passage 15. 16 is installed around the boss portion 1d of the stretching disk 1. This air date distributor 16
The stretching disk 1 is kept stationary even when it rotates, and the space formed around the boss portion 1d is connected to a lower part of the stretching disk 1 which is connected to a compressed air supply source (not shown) by means of a seal plate 16a. Compressed air storage section 16b and upper atmosphere opening section 1 communicating with the atmosphere
It is divided into 6c. Then, by supplying compressed air to the cylinder portion 12 in a range approximately semi-circumferential at the bottom of the stretching disk 1, the head portion of the gripping tool 11 is
1a against the gripping surface 1b, and stretch the stretching disk 1.
By removing compressed air from the cylinder portion 12 in a certain upper range, the gripping tool 11 is separated from the gripping surface 1b by the restoring force of the spring 14.

Further, a belt groove 17 is provided on the outer circumferential surface of the front edge of the outer circumferential rim portion of the stretching disk 1 over the entire circumference. This belt groove 17 is formed to a depth that allows the belt 3 to be buried below the outer peripheral surface of the disk. On the other hand, in the stretching uniformity disk 2, a belt engagement groove 21 is formed at the center of the outer circumferential surface of the disk 2 over the entire circumference. Then, the stretching uniformity belt 3
is engaged with the belt groove 17 of the stretching disk 1 and the belt engagement groove 21 of the stretching uniformity disk 2 over the aforementioned predetermined range. The belt 3 is made of solid rubber, rubber with various reinforcing core materials, fiber rope,
It is made of materials with high strength and heat resistance, such as resin-impregnated fiber rope and steel wire, and has a circular cross-section. In addition, if necessary, in order to smooth the transfer operation of the belt 3 at a point close to the disks 1 and 2, a belt transfer guide bar (not shown) or the like may be provided near the point close to the disks 1 and 2, or as shown in FIG. As shown in FIG. 2, steps may be provided on the circumferential surfaces of both the front and rear sides of the belt groove 17 in the stretching disk 1.

Next, the operation of this device will be explained.

First, a flat film F ₀ is fed into the heating chamber 4 by the feeding nip roll 5, heated to a temperature suitable for stretching, and placed between both stretching disks 1 and 1'. Both sides are each disk 1,
1' along the gripping surface 1b. Then, at the gripping start points A and A', the gripping tool 11 operated by the gripping tool operating mechanism moves forward, and its head 11a is pressed against the gripping surface 1b, so that the original film _F0 is The sides are gripped. Then, the film is transported over a substantially semicircular range on the lower half side of both stretching disks 1, 1' with both sides of the film being gripped as described above. As a result, the film F is gradually stretched laterally while being sent downward along the downwardly expanding arcuate trajectory until it reaches the lowest point of the stretching disks 1, 1'.
From the lowest point of the sheet, the sheet is turned upside down and then sent upward along an upwardly expanding arcuate trajectory and further horizontally stretched. In this case, the stretching uniformity belt 3,
3' does not grip the film F at the portion that engages with the stretching discs 1, 1', but moves in the direction of rotation of the stretching discs 1, 1' while being immersed in the belt groove 17;
The vicinity of both sides of the film F comes to lie along the outer surface of the belts 3, 3'.

After this stretching process, when the stretching disks 1, 1' and the stretching uniformity disks 2, 2' reach the proximity point B, B', the gripping tool is released from the gripping surface 1b of the stretching disks 1, 1'. 11, the film is released from being gripped by the stretching disks 1, 1'. At the same time, as the belts 3 and 3' move, the side _E1 of the film F is guided by the belts 3 and 3' and is reversed and moved toward the outer peripheral surface of the stretching uniformity disks 2 and 2'. Then, it enters between the belt engagement groove 21 of the stretching uniformity disks 2, 2' and the belts 3, 3'.

The both sides of the film F transferred to the stretching uniformity disks 2, 2' continue from the vicinity of the above-mentioned proximal points B, B' to the film take-out points C, C', and the film F is transferred to the stretching uniformity disks 2, 2'. , 2' and each belt 3,
3', it moves approximately parallel to the outer periphery of the stretching uniformity disks 2, 2'.
Therefore, the stretched film F is kept at a substantially constant width and moved within a certain range while being heated, during which the stretching unevenness is eliminated and the stretching is made uniform. In other words, immediately after stretching, uneven stretching and variations in internal stress remain due to the difference in moving speed between both sides of the film in the width direction and the center in the width direction during the stretching process. If the stretched film is simply taken out via a take-out turn roll or the like, the film will shrink after being stretched and the stretching ratio, wall thickness, etc. will become non-uniform. On the other hand, if the stretching uniformity mechanism is used to move the stretched film over a fixed width while heating it over a certain period, uneven stretching and variations in internal stress can be absorbed, and the stretching ratio, wall thickness, etc. can be made uniform. be converted into In particular, by directly connecting the stretching mechanism and the stretching uniformity mechanism, the stretching uniformity effect is effectively performed, and moreover, the film can be transferred from the stretching mechanism to the stretching uniformity mechanism by the belts 3, 3'. The film can be easily and reliably replaced and held by the stretching and uniformizing mechanism.

Film F after stretching and stretching uniformization process
The cutter 6,
After the side edge portions F ₁ are separated by 6', they are taken out to the outside via the turn roll 7 and the nip roll 8 for take-up, and the edge portion F ₁ is separately discharged via the nip roll 9 and the like.

The both stretching uniformity disks 2, 2' are basically arranged parallel to each other and perpendicular to the stretching disks 1, 1', but they may be arranged inwardly or inwardly to the extent that the stretching uniformity effect is not impaired. It may be arranged so as to be slightly inclined outward.

Further, as a processing means for the film after stretching and uniformization, as shown in FIG. A subsequent step for heat treatment can also be incorporated. In this step, when obtaining a heat-shrinkable film, all roll groups 41 to 46 are cooled, or the first and second roll groups are cooled.
The rolls 41 and 42 are heated to the stretching temperature and the other rolls 43 to 46 are cooled, and when complete heat treatment is performed, the first to third rolls 41 to 43 are heated to the heat treatment temperature and the other rolls 44 to 46 are cooled. 46 should be cooled. Alternatively, the film may be rapidly cooled after being stretched uniformly, and then heat treated using a separate heat treatment apparatus.

The specific structure of the device of the present invention can be modified in various ways other than the above embodiments, and some examples will be explained below.

When the gripping tool 11 is used as the stretching gripping means, its operating mechanism may include the above-mentioned pneumatic operating mechanism or, although not shown, a fixed cam disk that may be used to move the gripping tool in the circumferential direction. A cam-type actuation mechanism for advancing and retracting can also be used.

Further, as another example of the holding means for stretching, the ninth
As shown in the figure, on the outer periphery of a pair of left and right stretching disks (one not shown), a large number of gripping tools 51 that can move forward and backward in the radial direction of the disks 50 are arranged at equal intervals in the circumferential direction. The tool 51 is operated by a pneumatic or cam-type operating mechanism according to the rotation of the stretching disk 50, and the inner peripheral surfaces on both front and rear sides of the head 51a of the gripping tool 51 and the outer peripheral gripping surface 50a of the stretching disk 50 are connected. The side portion of the film F may be gripped in between. According to this structure, two films F,
It is also possible to simultaneously stretch F, or to simultaneously stretch the tubular film by dividing it into two parts, front and back. In this case, a stretching uniformity mechanism may be used on both the front and rear sides of the stretching disk 50. Or again,
As shown in FIG. 10, a stretching belt engagement groove 61 is provided in the center of each outer circumferential surface of a pair of left and right stretching discs (one not shown), and a stretching belt engagement groove 61 is provided on the lower half side of the stretching disc. Stretching belt 62 over a predetermined range
The belt 61 may be engaged with the stretching disk 60 so that the side portion of the film can be gripped between the belt 61 and the stretching disk 60. According to this structure, it is also possible to stretch the tubular film f. In this case, a stretching uniformity mechanism is provided on both the front and back sides of the stretching disk 60, and the stretching is performed near a point near the stretching disk 60 and the stretching uniformity disk. A cutter 63 that cuts the finished film into two parts may be provided.

The apparatus of the present invention can similarly stretch not only plastic films but also mesh webs, horizontal parallel bodies of filamentous materials, and the like.

As explained above, the stretching device of the present invention uses a pair of stretching disks arranged at a predetermined distance in substantially the same plane and a stretching gripping means to feed a material to be stretched in a direction that spreads out. Due to the mechanism,
It has a compact structure that enables high-magnification and high-accuracy stretching, and it also has a pair of stretching uniformity disks that are substantially parallel to each other and are placed at a right angle to the stretching disk and close to the end position of the stretching range of the disk. Since the stretched film is moved over a certain range while maintaining a substantially constant width using the stretching uniformity belt, it is possible to eliminate stretching unevenness. In particular, since the stretching process and the stretching uniformity process are made almost continuous, the stretching uniformity effect is high, and the film after stretching is guided by the belt to the stretching uniformity disc, and the film is guided to the stretching uniformity disc by the belt. Since it is gripped upward, it has many excellent effects, such as being able to reliably uniformize the stretching despite its simple structure.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the overall structure of an embodiment of the device of the present invention, FIG. 2 is a front view of the same, FIG. 3 is a side view of the same, and FIG. 4 is an enlarged partially sectional plan view of the main parts. Fifth
The figure is a sectional view showing the state of the belt transition point part after the transition, FIG. 6 is a sectional view taken along the - line in FIG. 4,
Fig. 7 is a cross-sectional view showing another example of the shape of the belt groove of the stretching disk, Fig. 8 is a side view showing an example in which cooling and heat treatment of the film after uniform stretching is incorporated, and Fig. 9 is a sectional view showing another example of the shape of the belt groove of the stretching disk. FIG. 10 is an enlarged sectional view of the main part showing another embodiment of the holding means for stretching. FIG. 10 is an enlarged sectional view of the main part showing still another embodiment of the holding means for drawing. 1, 1', 50, 60... Stretching disk, 11,
51, 62... Gripping means for stretching, 2, 2'... Disc for uniformizing stretching, 3, 3'... Belt for uniformizing stretching.

Claims (1)

[Scope of utility model registration request] A pair of stretching disks are arranged in the heating area of the material to be stretched so as to rotate in opposite directions at a predetermined interval on the left and right in substantially the same plane, and a While holding both sides of the material to be stretched in a state where they are attached to the periphery of each stretching disk over a stretching range of approximately semi-circumference that diverges from each other along the rotation direction, as both stretching disks rotate. By providing a stretching gripping means for moving the stretching material, a stretching mechanism is constructed that sends the material to be stretched to the end and stretches it, and a pair of stretching equalizing means that face each other in parallel and rotate synchronously in a predetermined direction are provided. The disks are arranged close to the end positions of the stretching ranges of the respective stretching disks and substantially perpendicular to each of the stretching disks, and a pair of endless stretching uniformity belts are connected to the stretching disks and the stretching uniformity belts, respectively. The belt is passed over each stretching disk, each stretching uniformizing disk, and the guide pulley in such a state that the belt is transferred from the stretching disk to the stretching uniformity disk at a point close to the disk, and each belt is used to transfer the stretched material to the stretching disk. Transfer both sides of the material from each stretching disk to each stretching uniformity disk, and move it over a predetermined range of the stretching uniformity disk while holding it between the circumferential surface of each disk and each belt. A stretching device for plastic film, etc., characterized in that it is configured as follows.