KR101213521B1 - Manufacturing method for biaxial stretched film and manufacturing equipment for biaxial stretched film - Google Patents

Abstract

The biaxially stretched film manufacturing apparatus is elastically provided with the pair of elastic support rolls 81 which elastically support both ends of the base film 2 in the width direction outer side of the base film 2 in the upstream of the heat processing apparatus 40. The support apparatus 80 is provided. The elastic support roll 81 is comprised of two sets, the cylindrical shape which can reversely rotate with each other with advancing of the base film 2 while applying the linear pressure by interposing the base film 2 from both surfaces. It has a rotating part.

Description

Manufacturing method of biaxially-stretched film, and biaxially-stretched film manufacturing apparatus {MANUFACTURING METHOD FOR BIAXIAL STRETCHED FILM AND MANUFACTURING EQUIPMENT FOR BIAXIAL STRETCHED FILM}

1 is a schematic view of a biaxially stretched film production apparatus according to an embodiment of the present invention.

2 is a side view of a clip in the above embodiment.

3 is a schematic view of the elastic support device in the embodiment as seen in the horizontal direction.

It is a figure which shows the trouble example of the elastic support roll in the said embodiment.

It is a figure which shows the trouble example of the elastic support roll in the said embodiment.

5 is a schematic view of the heat treatment apparatus and the elastic support apparatus of the above embodiment as viewed from above.

<Explanation of symbols for main parts of drawing>

1: disc film 2: base film

3: biaxially oriented film 10: tubular stretching device

11: guide board 12: pinch roll

20: preheating furnace 30: separation device

31: guide roll 32: trimming device

33A, 33B: Separation Roll 34A, 34B, 34C: Groove Forming Roll

40: heat treatment device 41: tenter

42: heating furnace 50: tension control device

51A, 51B: Free Roll 52: Dancer Roll

60: winding device 61: guide roll

62: winding roll 80: elastic support device

81A, 81B: Elastic support roll 100: Biaxially stretched film production apparatus

The present invention relates to a method for producing a biaxially oriented film and a biaxially oriented film production apparatus.

Generally, since a biaxially stretched film is excellent in mechanical strength and heat resistance, it is used as what is called a marking material in the field of packaging materials. Especially, since a biaxially stretched nylon film is especially excellent in mechanical strength and puncture resistance, it is widely used for liquid packaging, heavy weight packaging, etc.

When manufacturing such a biaxially stretched film, it is common to heat-process (heat fixation) to the base film after extending | stretching. By heat processing, the heat resistance of a base film etc. improve remarkably, and it becomes a biaxially stretched film excellent in practical use. As the heat treatment method, a tenter method is generally used. Specifically, heat treatment is performed by traveling in the heat treatment apparatus while fixing both ends of the base film after biaxial stretching with a clip or the like.

Even when manufacturing a biaxially stretched nylon film, the tenter system is generally employ | adopted for heat processing. On the other hand, it is known that if the base film biaxially stretched by the tubular method is folded as it is and heat treatment is performed as a two-layer laminated film, thermal fusion is caused during the heat treatment. Therefore, the tube-shaped base film after biaxial stretching is cut once, the inner surface of the base film is exposed to the outside air, and preheating treatment is performed, whereby subsequent heat treatment can be performed smoothly (for example, Japanese Patent Laid-Open No. 2-141225).

However, although the method of Unexamined-Japanese-Patent No. 2-141225 introduces two upper and lower base films into a heat processing apparatus after preheating, the two upper and lower base films shift | deviate, or the base film bends by moisture in the air at that time. It may become difficult to introduce into a heat processing apparatus. Furthermore, in the case where the heat treatment apparatus is a tenter system, if the gripping of the base film end portion by the clip is unstable, there may be a problem such that the base film itself is pulled out of the clip by the contracting force of the base film itself, or the base film breaks in the vicinity of the clip. .

Therefore, the main objective of this invention is providing the manufacturing method of the biaxially stretched film which introduce | transduces the base film after biaxial stretching smoothly into a heat processing process, and the biaxially stretched film manufacturing apparatus for it.

The manufacturing method of the biaxially stretched film of this invention is a manufacturing method of the biaxially stretched film containing the biaxially stretching process and the heat processing process of heat-processing the base film after biaxial stretching, The said base material in the upstream of the said heat processing process And an elastic support step having a pair of elastic support means for elastically supporting both ends of the film to the outside in the width direction of the base film.

Here, a pair of elastic support means should just be able to elastically support with respect to the both ends of a base film in the width direction outside, For example, a strong wind is projected from both surfaces of a base film through something like a thin slit, and a base film The means for elastically supporting this may be sufficient.

According to the manufacturing method of the biaxially stretched film of this invention, when introducing a base film into a heat processing process, elastic support which has a pair of elastic support means which respectively elastically support both ends of a base film in the width direction outer side of a base film Since the process provides a process, even if both ends of a base film are bent, relaxed, or the whole base film shakes left and right, a base film can be introduce | transduced into a heat processing process reliably.

Therefore, the position of this elastic support process should be closer to a heat processing process. For example, when the heat treatment step adopts the tenter method, the position of the elastic support step is preferably within 1 m from the starting point of the insertion of the base film by the clip in the tenter, more preferably within 50 cm.

Moreover, a plurality of pairs of elastic support means mentioned above may exist in an elastic support process. For example, when a pair of elastic support means is arrange | positioned several times in the advancing direction of a base film, the elastic support effect with respect to a base film is more excellent.

In the present invention, the elastic support means is a pair of elastic support rolls having a cylindrical rotating portion that is inserted into both sides of the base film on both sides to apply a linear pressure, and can be reversely rotated with the progress of the base film desirable.

According to this invention, two cylindrical rotating parts are parallel to each other, and the base film is crimped together from both surfaces. Moreover, since this pair of elastic support rolls is a pair at both ends of the advancing direction of a base film, an elastic support roll can elastically support both ends of a base film to the outside of the width direction reliably. Specifically, both ends of the base film are strongly pulled outward in the width direction, and even if both ends of the base film are bent, the effect of preventing warpage is strongly acted on. For example, if the heat treatment apparatus is a tenter system, both ends of the base film can be smoothly guided to the clip of the tenter.

Moreover, it is preferable that the rotating part of this elastic support roll is what is called free roll which rotates freely. Since the free roll rotates automatically by advancing of the base film itself, and the force which elastically supports a base film outside the width direction acts, an unnatural force does not act on a base film. That is, the elastic support effect by an elastic support roll can be exhibited at the natural rotational speed suitable for the advancing speed of a base film.

In this invention, it is preferable that it is 6-500 gf / cm, and, as for the linear pressure applied to the said base film by the said cylindrical rotating part, it is more preferable that it is 50-200 gf / cm.

According to the present invention, since the linear pressure applied to the base film by the cylindrical rotating part is in a predetermined range of 6 to 500 gf / cm, the elastic support effect to the base film is sufficiently exhibited, and the cause of film breakage, etc. There is little concern.

In this invention, the said base film is conveyed substantially horizontally to the said heat processing process, The longitudinal direction length (L1) of the rotation part located above the said base film with respect to the said two sets of elastic support rolls, and of the said base film It is preferable that ratio L1 / L2 of the longitudinal direction L2 of the rotating part located in the lower side is 1-3.

Here, L1 and L2 are the length from the base (base film end side) of a rotating part to the top part (base film center side), and the bases of both rotating parts are at about the same position mutually in an up-down direction.

According to this invention, since ratio (L1 / L2) of the longitudinal direction length L1 of the rotation part located in the upper side of a base film, and the longitudinal direction length L2 of the rotation part located in the lower part of a base film is 1-3, When the base film is in progress, so-called film breaking is rarely caused. That is, although the length of the rotation part of mutually elastic support roll mutually may be the same, when changing length, it is better to make L1 (upper) side longer than L2 (lower side) as mentioned above.

When L2 (lower side) is longer than L1 (upper side), there exists a possibility that the front-end | tip of the rotation part of the elastic support roll located above the base film may damage the base film surface by the vibration at the time of operation.

Moreover, when this cylindrical rotation part is not parallel with respect to a base film surface, but has the angle which the front-end | tip hits with respect to a base film surface, it is easy to be damaged in a film surface, and it becomes easy to be a cause of breakage. Therefore, it is preferable that the longitudinal direction of a rotating part maintains the angle within 10 degrees with respect to a base film surface.

In this invention, it is preferable that the angle formed in the downstream side by the longitudinal direction of the said elastic support roll and the width direction of the said base film is 20-70 degrees.

According to this invention, since the angle formed by the longitudinal direction of an elastic support roll and the width direction of a base film exists in the specific range at 20-70 degrees, both ends of a base film can be elastically supported effectively outside the width direction. . If this angle is less than 20 degrees, the tensile force in the width direction of a base film will run short, and it will become difficult to introduce a base film into a heat processing apparatus smoothly. For example, when a tenter system is used as a heat processing apparatus, a base film will fall easily from a clip. On the contrary, when this angle exceeds 70 degrees, the force which pulls a base film to the left and right of a flow direction is too strong, causing left and right shake, and lacks stability.

This angle becomes like this. Preferably it is 30-60 degrees, More preferably, it is 30-50 degrees.

Moreover, when the rotating part of an elastic support roll is a free roll, since the free roll itself acquires a rotational force by the flow of a base film, and an elastic support effect is exhibited by the rotational force, this angle setting is more important.

In this invention, it is preferable that biaxial stretching is a tubular system.

According to the present invention, since biaxial stretching is a tubular system, simultaneous biaxial stretching in the MD direction (moving direction of the film) and the TD direction (direction orthogonal to the moving direction of the film) can be performed, and the resulting biaxial stretching is obtained. The film is excellent in the strength balance of the MD direction and the TD direction.

The biaxially stretched film manufacturing apparatus of this invention is a biaxially stretched film manufacturing apparatus containing the heat processing apparatus which heat-processes the base film after biaxial stretching, and the both ends of the said base film are respectively the upstream side of the said heat processing apparatus, The said base film And an elastic support device having a pair of elastic support means for elastic support on the outside in the width direction thereof.

According to the biaxially stretched film manufacturing apparatus of this invention, when introducing a base film into a heat processing apparatus, the elastic support apparatus which has a pair of elastic support means which respectively elastically support both ends of a base film in the width direction outer side of a base film. Since the both ends of the base film are bent, relaxed, or the whole base film shakes from side to side, the base film can be introduced into the heat treatment apparatus reliably.

In this invention, it is preferable that the said elastic support means is a set of two elastic support rolls which have the cylindrical rotation part which can pinch | interpose said base film from both surfaces, apply a linear pressure, and can reverse-rotate with each other with advancing of a base film.

According to this invention, the rotation part of two sets of elastic support rolls pinches a base film from both surfaces, and applies linear pressure. That is, two cylindrical rotating parts are parallel to each other, and the base film is pressed against both surfaces. Moreover, this pair of elastic support rolls are a pair of both ends of the advancing direction of a base film, and an elastic support roll can elastically support both ends of a base film to the outside of a width direction reliably.

Embodiments of the Invention

EMBODIMENT OF THE INVENTION Below, the best form for implementing the manufacturing method of the biaxially stretched film which is this invention is explained in full detail based on drawing. Specifically, the apparatus and its operation constituting each step of biaxially oriented film production will be described in detail.

[Summary of biaxially stretched film manufacturing apparatus]

FIG. 1: is a schematic diagram which shows the biaxially-stretched film manufacturing apparatus 100 of the tubular system as an example of this invention.

As a raw material of the biaxially stretched film manufactured by this biaxially stretched film manufacturing apparatus 100, polyolefins, such as polypropylene (PP) and polyethylene (PE), polyester, such as PET and PBT, nylon 6, nylon 66, etc. Polyamide resin and the like are preferably used. Among these, application to the polyamide resin in which the curvature of the base film after biaxial stretching becomes a problem is preferable.

The biaxially stretched film production apparatus 100 includes a biaxially stretched apparatus (tubular stretching apparatus) 10 for stretching the unstretched raw film 1 (hereinafter also referred to as the master film 1), A preheating apparatus (preheater) 20 for preheating the folded base film 2 (hereinafter also referred to simply as film 2) after stretching, and a separation device for separating the preheated film 2 into two sheets above and below ( 30, a heat treatment apparatus 40 for heat treating (heat-setting) the separated film 2, and a tension control apparatus 50 for applying tension to the film 2 from the downstream side when the film 2 is heat treated. And a winding device 60 for winding up the biaxially stretched film 3 (hereinafter, also simply referred to as film 3) in which the film 2 is heat treated.

The tubular stretching apparatus 10 is an apparatus for producing the film 2 by biaxially stretching the tubular disc film 1 produced by an extruder (not shown) by the pressure of internal air. And the guide plate 11 and the pinch roll 12 are provided as a means of folding this film 2 flat and sending it to the downstream preheating furnace 20.

The preheating furnace 20 is an apparatus for preliminarily heat treating the flattened film 2. The film 2 is heat-treated in advance at a temperature of about 30 ° C. lower than the melting point of the film 2 or lower than the shrinkage start temperature of the film 2. By this preliminary heat treatment, the crystallinity of the film 2 increases, and the lubricity of superimposed films becomes favorable.

The separation device 30 includes a guide roll 31, a trimming device 32, separation rolls 33A and 33B, and groove forming rolls 34A to 34C.

The trimming device 32 has a blade 321, and cuts both ends of the flat film 2 sent through the guide roll 31 and separates it into two base films 2A and 2B. And these are isolate | separated, with air interposed between the both films 2A and 2B sent through the guide roll 31 by the pair of separation rolls 33A and 33B which are separated up and down. The cutting of this flat film 2 may be performed so that a partial part may be formed by positioning the blade 321 slightly inward at both ends, or the blade 321 at the fold portion of the film 2. You may perform so that a tooth part may not generate | occur | produce.

Next, both films 2A and 2B are stacked again by three groove forming rolls 34A to 34C sequentially positioned in the advancing direction of both films 2A and 2B. Moreover, these groove formation rolls 34A-34C give a plating process to the surface after groove formation process. Through this groove, a good contact state between the films 2A and 2B and air is obtained.

The film 2 sent out from the separating apparatus 30 is introduced into the heat treatment apparatus 40 through the elastic support apparatus 80 mentioned later.

The heat treatment apparatus 40 is a tenter 41 which is a means for holding both ends of two films 2A and 2B, and a heating furnace 42 that is a heating means for heat treatment of two films 2A and 2B held at both ends. ). This heating furnace 42 is a hot stove here.

The films 2 (2A, 2B) in the overlapped state are about 30 ° C. at or below the melting point of the resin constituting the film 2 while holding both ends with the clip 411 (FIG. 2) of the tenter 41. It heat-processes (heat-fixes) above low temperature, and becomes the biaxially stretched film 3 (henceforth called the film 3) with stable physical properties.

2, the side view of the clip 411 used by the tenter 41 is shown.

The clip 411 is made of metal, and the base portion 411A, the arm portion 411B extending from the base portion 411A, the support shaft 411C positioned at the tip of the arm portion 411B, and the support shaft 411C. It is configured to include a wing 411D and a wing 411E which can freely rotate by a predetermined angle in conjunction with only a predetermined direction around the. A part of the upper surface of the base portion 411A is a plate 411A1 made of silicon rubber.

The clip 411 performs predetermined opening / closing operation | movement with respect to the blade | wing 411D, and the wing | tip 411E which cooperates performs opening / closing operation | movement, and the edge part of the film 2 is strongly strengthened by the blade | wing 411E and the plate 411A1. Cooperate. When the film 2 undergoes heat treatment and tries to shrink, this clamping force is configured to be stronger.

The tension control device 50 (FIG. 1) is provided with two free rolls 51A and 51B and the dancer roll 52 which is located in the middle and which can be displaced (moved) up and down.

The film 3 sent out from the heat treatment apparatus 40 is sent out from the free roll 51B to the winding device 60 after passing through the free roll 51A and the dancer roll 52.

The free rolls 51A and 51B only rotate freely in accordance with the progress of the film 3 from the heat treatment apparatus 40, but the dancer roll 52 is displaceable up and down. Therefore, when the dancer roll 52 is displaced downward, the tension of the film 3 becomes large, and conversely, when the dancer roll 52 is displaced upward, the tension of the film 3 becomes small. That is, by the up-and-down displacement of the dancer roll 52, tension control with respect to the film 2 heat-treated in the heat processing apparatus 40 located upstream is attained.

The winding device 60 is equipped with the guide roll 61 and the winding roll 62. As shown in FIG. The heat-fixed film 3 is wound as two films 3A and 3B on the two winding rolls 62 via the tension control device 50 via the guide roll 61.

[Summary of elastic support apparatus]

3 is a schematic view of the elastic support device 80 viewed in the horizontal direction.

The elastic support apparatus 80 has the elastic support roll 81 as a pair of elastic support means which elastically support the both ends of the folded film 2 (2A, 2B) to each outside in the width direction. In this embodiment, this pair of elastic support rolls are symmetrical in both the shape and arrangement | positioning. In addition, as shown in FIG. 3, the elastic support roll 81 is arrange | positioned one by one above and below film (2) (2A, 2B), and the upper side elastic support roll 81A and the lower side elastic support roll 81B. There is one set of.

The elastic support roll 81A is comprised with the shaft center 811A and the cylindrical rotation part 812A fixed to the shaft center 811A by rotating materials. The elastic support roll 81B is also provided with the shaft center 811B and the cylindrical rotating part 812B exactly the same. The base 812A1 of the rotating part 812A and the base 812B1 of the rotating part 812B are at the same position in the up-down direction.

The rotating portion 812A is, for example, a cylindrical structure having a diameter of about 1 to 5 cm and a longitudinal length L1 of about 10 to 30 cm, and the rotating portion 812B has a diameter of, for example, 1 to 5 cm. It is a cylindrical structure with a length of about 5 cm and a length L2 of about 3 to 20 cm. If the longitudinal lengths L1 and L2 of the rotating portions 812A and 812B are too long, the film 2 may flow along the width of the heat treatment apparatus 40, but there is a fear that the resistance to flow becomes too large. In addition, when the longitudinal lengths L1 and L2 of the rotating portions 812A and 812B are too short, the elastic support effect to the film 2 is not sufficient, and the warpage and the like at the ends of the film 2 are not fully controlled, and furthermore, the film (2) An end part is easy to be pulled out from the clip 411 (FIG. 5) in the heat processing apparatus 40. FIG.

Here, it is preferable that ratio (L1 / L2) of the longitudinal length L1 of the rotating part 812A, and the longitudinal length L2 of the rotating part 812B is 1-3. Although the length of the rotation part 812A and the rotation part 812B may be the same, when changing length, it is better to make L1 longer than L2. L1 / L2 is more preferably 1.5 to 2.5.

When L1 and L2 are the same length, the elastic support roll tip parts may contact each other through the film 2 by the vibration at the time of a driving | operation, and a possibility of being damaged on the film 2 surface by a blade effect (edge effect). There is this. In addition, as shown in FIG. 4A, even when the rotating part 812B (lower side) is longer than the rotating part 812A (upper side), the tip of the rotating part 812A located above the film 2 is driven by the vibration at the time of operation. There is a risk of scratching the surface of the film 2A. For example, in FIG. 3, when L2 is longer than 20 cm, it is necessary to make L1 about 30-60 cm. However, in that case, the resistance with respect to the film 2 flowing in the heat processing apparatus 40 will become excessive.

As a material of the rotating parts 812A and 812B, metals, such as stainless steel, and heat resistant plastics, such as bakelite, are used preferably. In the case of using a metal, durability is improved by chromium plating on the surface.

As the material of the rotating portions 812A and 812B, both metals may be used from the viewpoint of durability, but one of them is preferably a heat-resistant plastic that is softer than the metal. In the case where the materials of the rotating portions 812A and 812B are all made of metal, when continuous operation is performed for a long time, fine scratches may occur on the surface of the rotating portion, and the scratches may cause breakage (notch generation) with respect to the film 2. There is this.

In addition, since a heat resistant plastic is hard to scratch a surface of the film 2, it is preferable to use it as a material of the rotating part 812B located under the film 2. As shown in FIG.

In addition, as shown to FIG. 4B, this rotating part 812A or the rotating part 812B is not parallel with respect to the surface of the film 2, and the front-end | tip is angled with respect to the surface of the film 2 at an angle (Φ). If it has, it will be easy to be damaged in a film surface, and it will be easy to cause a film break.

Therefore, it is preferable that this angle (phi) is 10 degrees or less. Angle (phi) becomes like this. More preferably, it is 5 degrees or less.

Moreover, although these rotating parts 812A and 812B apply the linear pressure by sandwiching the film 2 from both surfaces, about 6-500 gf / cm is preferable as linear pressure. If linear pressure is less than 6 gf / cm, the deflection prevention effect of the edge part of the film 2 and the anti-deviation effect of the film 2 will be lacking. In addition, the film 2 is easily detached from the clip 411. On the other hand, when the linear pressure exceeds 500 gf / cm, the film 2 tends to break.

Moreover, since rotation part 812A, 812B is what is called a free roll, it rotates in a reverse direction mutually, applying a linear pressure to film 2 with advancing (flow) of film 2.

5 is a schematic view from above of the film 2 introduced into the heat treatment apparatus 40 through the elastic support apparatus 80, the heat treatment apparatus 40, and the elastic support apparatus 80. The film 3 after the heat treatment is sent out from the heat treatment apparatus 40 and wound around the winding apparatus 60 (FIG. 1).

The elastic support roll 81 is set to the angle (θ) formed downstream by the longitudinal direction of the elastic support roll 81 and the width direction of the film 2. It is preferable that angle (theta) is 20-70 degrees here.

If this angle is less than 20 degrees, the tensile force in the width direction of a base film will become short, and it will become difficult to introduce a base film into a heat processing apparatus smoothly. For example, in this embodiment, since the tenter system is used as a heat processing apparatus, the film 2 will fall easily from the clip 411. On the contrary, when this angle exceeds 70 degrees, the force which pulls the base film to the left and right of a flow direction is too strong, causing left and right shake, and lacking stability.

This angle (theta) becomes like this. Preferably it is 30-60 degrees, More preferably, it is 30-50 degrees. Moreover, this elastic support roll 81 can change the angle of a horizontal direction and a vertical direction freely.

In addition, since it is better to immediately transfer the film 2 to the heat treatment apparatus 40 after both ends of the film 2 are elastically supported, the elastic support apparatus 80 is disposed near the inlet of the heat treatment apparatus 40. It is. It is preferable that it is within 1 m from the insertion start point of the base film by the clip 411 in the tenter 41 specifically, More preferably, it is within 50 cm.

According to embodiment mentioned above, the following effects can be exhibited.

(1) The biaxially stretched film manufacturing apparatus 100 has the elastic support apparatus 80 which has a pair of elastic support rolls 81 which elastically support both ends of the film 2 in the width direction outer side of the film 2 Since both ends of the film 2 are bent or the whole film 2 deviates from side to side, the heat treatment process in the heat treatment apparatus 40 is stabilized, and the continuous molding of the biaxially stretched film is performed for a long time. This becomes possible.

(2) Since the rotating parts 812A and 812B of the elastic support roll 81 are so-called free rolls which rotate freely, the rotating parts 812A and 812B automatically rotate by the progress of the film 2 itself, and the film 2 ) Acts elastically on the outside in the width direction, so that unnatural force is not applied to the film 2. That is, the elastic support effect by the elastic support roll 81 can be exhibited at the natural rotational speed suitable for the advancing speed of the film 2.

(3) The rotating parts 812A and 812B of the two sets of elastic support rolls 81 are mutually parallel, and the film 2 is crimped | bonded from both surfaces, Moreover, this set of elastic support rolls 81 is a film Since there is a pair at both ends of the advancing direction of (2), the elastic support roll 81 can elastically support both ends of the film 2 to the outside in the width direction reliably.

(4) Since the angle (theta) of the downstream side formed by the longitudinal direction of the elastic support roll 81, and the width direction of the film 2 exists in the specific range in 20-70 degrees, both ends of the film 2 Can be elastically supported to the outside in the width direction effectively.

(5) Since the linear pressure applied to the film 2 is in a predetermined range of 6 to 500 gf / cm, the elastic support effect to the film 2 is fully acting, and there is a fear of causing film breakage or the like. little.

(6) Ratio L1 of the longitudinal length L1 of the rotating part 812A located above the base film 2, and the longitudinal length L2 of the rotating part 812B located below the base film 2; Since / L2 is 1-3, so-called film breaking is rarely caused during the progress of the base film.

(7) Since the position of the elastic support device 80 is near the insertion start point of the base film by the clip 411 in the tenter 41, the elastic support effect by the elastic support device 80 is sufficiently exhibited. easy.

Although the best structure for implementing this invention, etc. are disclosed by the above description, this invention is not limited to this. That is, the present invention has been mainly described with respect to specific embodiments, but those skilled in the art will appreciate that various changes in the structure, materials, and other detailed configurations of the above-described embodiments are possible without departing from the technical spirit and desired range of the present invention. It can be modified.

Accordingly, the descriptions limiting the structures, materials, and the like described above are described by way of example in order to facilitate understanding of the present invention, and are not intended to limit the present invention. The description excepting names are included in the present invention.

For example, in this embodiment, although the elastic support apparatus 80 is comprised by the pair of elastic support rolls 81 (one pair), even if two pairs, three pairs, or more elastic support rolls are arrange | positioned, do.

In addition, in this embodiment, although the pair of elastic support rolls 81 symmetrically with respect to the flow direction of the film 2, it does not necessarily need to be symmetrical. If the property of a film is not symmetrical with respect to a flow direction, you may change so that the shape of an elastic support roll may differ from right to left accordingly.

The rotary parts 812A, 812B of the elastic support roll 81 need not have a cylindrical shape, and may be, for example, a cone shape or a truncated cone shape.

In addition, in this embodiment, although the tubular system was employ | adopted as a biaxial stretching method, a tenter system may be sufficient. Further, the stretching method may be simultaneous biaxial stretching or successive biaxial stretching.

Moreover, in this embodiment, although the hot stove was used as the heat processing apparatus 40, well-known heating systems, such as infrared heating or roll heating, can be employ | adopted.

Example

Next, an Example and a comparative example demonstrate this invention further in detail. However, this invention is not limited at all by these examples. In addition, the part which is common as an apparatus etc. used the code | symbol same as the code | symbol in embodiment.

Example 1

In above-mentioned embodiment (FIG. 1, FIG. 5), specific conditions were set and the biaxially stretched nylon film 3 was manufactured.

As the crystalline thermoplastic resin, extruded from a 60 mm diameter cyclic die using polyamide-based nylon 6 (relative viscosity 3.7), followed by quenching in 15 ° C. cooling water, and a disc having a diameter of 90 mm and a thickness of 120 μm. The film 1 (tubular nylon film, shrinkage start temperature 45 degreeC, melting | fusing point 215 degreeC) was produced. While simultaneously heating the master film 1 using an infrared heater in the tubular stretching apparatus 10, the film was simultaneously biaxially stretched at a draw ratio MD (moving direction of the film) / TD (orthogonal direction) = 3.0 / 3.2 to a thickness. The 15-micrometer film (2) was obtained.

Next, this film 2 was continuously supplied to the guide plate 11 and the pinch roll 12, and it was folded, and it was set as the flat tube-like film 2.

Next, the flattened film 2 was transferred to a preliminary heat treatment apparatus (preheater) 20, and preheated at 170 ° C. for the film 2, and preliminarily processed. The inside of the preheating furnace 20 is provided with the clip 411 which runs by holding the edge part of the film 2 to the left and right.

Next, both ends of the flat film 2 are cut out by the trimming device 32 attached to the separating device 30 and separated into two films 2A and 2B, and then the films 2A and 2B are separated. It isolate | separated by the roll 33A, 33B, and made the inner surface contact with air, and was overlap | superposed again by passing through between the grooveless rolls 34A-34C. Next, the film 2A, 2B was introduce | transduced into the heat processing apparatus 40 at 80 m / min through the elastic support apparatus 80 which has a specification mentioned later.

In the heat treatment apparatus, the biaxially stretched nylon film 3 (film) is subjected to heat treatment (heat fixation) at 210 ° C. while holding both ends of the films 2A and 2B with a tenter 41 having a clip 411. (3A, 3B) was obtained.

And the continuous molding time in the heat processing (production of the film 3) of the film 2 was measured. Specifically, the biaxially oriented film is formed from the point of time when the winding of the film 3 by the winding device 60 is stabilized by the removal of the films 2 and 3 from the clip 411 and the breaking of the films 2 and 3. The time until manufacture was stopped was measured and it was set as continuous molding time.

Here, each specification regarding the elastic support apparatus 80 is as follows.

Shape of Rotating Part 812A

L1 = 20 cm, diameter 4 cm, stainless steel (surface is chrome plated)

Shape of Rotating Part 812B

L2 = 15 cm, diameter 4 cm, stainless steel (surface is chrome plated)

? Linear pressure T between the rotating parts 812A, 812B:

T = 134 gf / cm

Angle (acute angle) θ formed between the longitudinal direction of the elastic support roll 81 and the width direction of the film 2:

θ = 40 °

Angle (acute angle) Φ that the longitudinal direction of the elastic support roll 81 forms with the horizontal surface (the surface of the film 2):

Φ = 0 ° (both elastic support rolls (81A, 81B))

In Table 1, the specifications and continuous molding time of the elastic support apparatus 80 used by Example 1 and Examples 2-6 mentioned later and Comparative Examples 1 and 2 were shown.

Example 2

In Example 1, it carried out similarly to Example 1 except having changed the specification of the elastic support apparatus 80 as follows.

Shape of Rotating Part 812B

L2 = 10 cm, 4 cm in diameter, made of bakelite

Angle (acute angle) θ formed between the longitudinal direction of the elastic support roll 81 and the width direction of the film 2:

θ = 20 °

? Linear pressure T between the rotating parts 812A, 812B:

 T = 200gf / cm

[Example 3]

In Example 1, it carried out similarly to Example 1 except having changed the specification of the elastic support apparatus 80 as follows.

Shape of Rotating Part 812B

L2 = 10 cm, 4 cm in diameter, made of bakelite

Angle (acute angle) θ formed between the longitudinal direction of the elastic support roll 81 and the width direction of the film 2:

θ = 60 °

? Linear pressure T between the rotating parts 812A, 812B:

T = 200gf / cm

Example 4

In Example 1, it carried out similarly to Example 1 except having changed the specification of the elastic support apparatus 80 as follows.

Shape of Rotating Part 812B

L2 = 10 cm, 4 cm in diameter, made of bakelite

? Linear pressure T between the rotating parts 812A, 812B:

 T = 200gf / cm

[Example 5]

In Example 1, it carried out similarly to Example 1 except having changed the specification of the elastic support apparatus 80 as follows.

Shape of Rotating Part 812B

L2 = 10 cm, 4 cm in diameter, made of bakelite

Angle (acute angle) Φ in which the longitudinal direction of the elastic support roll 81 forms a horizontal plane:

 Φ = 10 ° (only elastic support roll (81A))

[Example 6]

In Example 1, it carried out similarly to Example 1 except having changed the specification of the elastic support apparatus 80 as follows.

Shape of Rotating Part 812A

L1 = 1Ocm, diameter 5cm, stainless steel (surface is chrome plated)

Shape of Rotating Part 812B

L2 = 10 cm, 4 cm in diameter, made of bakelite

Angle (acute angle) θ formed between the longitudinal direction of the elastic support roll 81 and the width direction of the film 2:

θ = 30 °

? Linear pressure T between the rotating parts 812A, 812B:

T = 160gf / cm

Comparative Example 1

In Example 1, it carried out similarly to Example 1 except not having provided the elastic support apparatus 80.

Comparative Example 2

In Example 1, it carried out similarly to Example 1 except having removed the elastic support roll 81A (upper roll) from the elastic support apparatus 80.

Installation of the elastic support roll Angle of Resilient Support Roll (θ) (°) Rotating part length ratio L1 / L2 Continuous Molding Time (Hr) Example 1 Yes ^{1 )} 40 20/15 ³⁾ 8 Example 2 Yes ^{1 )} 20 20/10 ³⁾ 12 Example 3 Yes ^{1 )} 60 20/10 ³⁾ 15 Example 4 Yes ^{1 )} 40 20/10 ³⁾ 24 Example 5 Yes ^{1 )} 40 20/10 ³⁾ 13 Example 6 Yes ^{1 )} 30 10/10 ³⁾ 20 Comparative Example 1 none - - 1.5 Comparative Example 2 Yes ^{2 )} (40) (-/ 15) 2.0

1) A set of elastic support rolls is installed above and below the base film

2) Install the elastic support roll only on the lower side of the base film

3) Ratio of rotation part length in upper and lower elastic support rolls

[result]

As shown in Table 1 and FIG. 3, in each Example, since the elastic support apparatus 80 (elastic support roll 81 satisfies predetermined conditions), the film 2 is smoothly introduced into the heat treatment apparatus. The breakage of the film 2 or the film 3 after the heat treatment hardly occurs, and the continuous molding time until the biaxially stretched film production apparatus stops is sufficiently long, that is, the elastic support roll 81 is a film. The film 2 is smoothly guided to the clip 411 at the inlet of the heat treatment apparatus 40 because it exhibits excellent elastic support effect (tension effect to the outside in the width direction) with respect to both ends of (2).

On the other hand, in the comparative example 1, since the elastic support roll is not provided at all, the both ends (this part) of the film 2 become unstable, and the films 2 and 3 are easy to pull out from the clip 411 of the tenter 41, The continuous molding time is very short.

Moreover, even if the elastic support roll 81B is provided only in the lower side of the film 2 like the comparative example 2, the elastic support effect to the film 2 hardly works, and continuous molding time does not improve.

As explained above, according to this invention, the manufacturing method of the biaxially stretched film which introduce | transduces the base film after biaxial stretching smoothly into a heat processing process, and the biaxially stretched film manufacturing apparatus for it are provided.

Claims (8)

As a manufacturing method of a biaxially stretched film containing a biaxial stretching process and the heat processing process of heat-processing the base film after biaxial stretching, An elastic support step having a pair of elastic support means for elastically supporting both ends of the base film to the outside in the width direction of the base film on an upstream side of the heat treatment step, The said elastic support means are two sets of elastic support rolls which apply the linear pressure by sandwiching the said base film between both surfaces, and have a cylindrical rotation part which can reversely rotate with each other with advancing of a base film. , The longitudinal length L1 of the rotary part located in the upper side of the said base film horizontally conveyed at the said heat processing process is larger than the longitudinal length L2 of the rotating part located in the lower side of the said base film, The biaxial axis characterized by the above-mentioned. Method for producing a stretched film. The method of claim 1, The ratio (L1 / L2) of the longitudinal length L1 of the rotary part located above the said base film, and the longitudinal length L2 of the rotary part located below the said base film is 1.5-3, It is characterized by the above-mentioned. The manufacturing method of a biaxial stretched film. The method of claim 1, The linear pressure applied to the said base film by the said cylindrical rotating part is 6-500 gf / cm, The manufacturing method of the biaxially stretched film characterized by the above-mentioned. The method of claim 1, The angle formed in the downstream side by the longitudinal direction of the said elastic support roll, and the width direction of the said base film is 20-70 degrees, The manufacturing method of the biaxially stretched film characterized by the above-mentioned. The method according to any one of claims 1 to 4, Biaxial stretching is a tubular system, The manufacturing method of the biaxially stretched film characterized by the above-mentioned. A biaxially stretched film manufacturing apparatus including a biaxial stretching apparatus and a heat treatment apparatus for heat treating a base film after biaxial stretching, An elastic support device having a pair of elastic support means for elastically supporting both ends of the base film to the outside in the width direction of the base film on an upstream side of the heat treatment apparatus, The said elastic support means are two sets of elastic support rolls which have the cylindrical rotation part which can pinch | interpose said base film from both surfaces, and apply a linear pressure, and can reverse-rotate with each other with advancing of a base film, The longitudinal length L1 of the rotating part located in the upper side of the said base film horizontally conveyed to the said heat processing apparatus is larger than the longitudinal length L2 of the rotating part located in the lower side of the said base film, The biaxial axis characterized by the above-mentioned. Stretched film production apparatus. delete delete

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