KR20090103700A - Method and apparatus for stretching polymer film, and solution film-forming method - Google Patents

Abstract

PURPOSE: A method and an apparatus for stretching a polymer film, and a solution film-forming method are provided to evenly stretch a polymer film by preventing the edge of the film from being crumpled. CONSTITUTION: A method and an apparatus for stretching a polymer film(3) and a solution film-forming method include a holding stabilizing process and a stretching process. A polymer film is gripped by a holder in the holding stabilizing process. The gripped width is stretched by gradually increasing the gripped width of the polymer film in the holding stabilizing process. The holding is stabilized by biasing the holder to the closed direction by the retraction of the stretched polymer film in the holding stabilizing process.

Description

Drawing method and apparatus of a polymer film, and solution film forming method TECHNICAL FIELD OF METHOD AND APPARATUS FOR STRETCHING POLYMER FILM, AND SOLUTION FILM-FORMING METHOD}

The present invention relates to a method for stretching a polymer film, an apparatus, and a solution film forming method.

Among the various polymer films used for optical purposes, in particular, the cellulose acylate film is produced by a solution film forming method. In this solution film-forming method, a dope is cast on a support body using a casting die, and after peeling this from a support body, a film is manufactured by winding up through a drying process.

The cellulose acylate film produced by the solution film forming facility is stretched in the film width direction in order to improve planarity, mechanical strength, optical properties, and the like. This extending | stretching is performed by pulling in the film width direction, holding both edge parts of a film with a clip, and conveying.

During film stretching, the film around the portion sandwiched by the clip is thinned by stretching, so that the film gripping force of the clip is reduced, and the film may come out of the clip during or after stretching. For this reason, in patent document 1, the tenter apparatus which provided the clip closure which applies the force in the direction which closes a clip in the range from the holding start position of a clip to a holding open position is proposed.

(Patent Document 1) Japanese Unexamined Patent Publication No. 2004-106422

However, as in Patent Literature 1, in order to bias the clip in the direction of closing the clip in order to eliminate the loosening of grip, it is necessary to provide a gripping force applying means, resulting in a complicated device configuration. In addition, in Patent Literature 1, which has a configuration that adds gripping force in order to eliminate gripping looseness, when the film is 110 μm or less or a film having a low volatility region having a low solvent content, the deformation margin of the film decreases, so that a sufficient effect cannot be obtained. Has a problem.

In addition, when holding a film by a clip, the film holding part of a clip needs to be fitted to a film without a gap. If there is a gap nonuniformity in this film holding part, it will become impossible to hold a film in this gap nonuniformity part. 5 is an enlarged display of the film 100 in which gripping nonuniformity has occurred, (A) shows a state in which one side is bitten, and (B) shows a state in which the middle is missing. The part indicated by hatching shows the holding area 101 by a clip. In (A), it can be seen that the right and left gripping areas 101a and 101b hold the film 100 without a gap, but in the gripping area 101c in the center, a gap is generated on the right side in (A). As a result, the right area cannot be gripped, and the film 100 is held only in the left area of the clip. In this way, if a gap is formed on one side of the clip in the center, the film 100 cannot be gripped at this gap generation portion, so that the film side edge 100a corresponding to this portion is recessed toward the center side. Crumpling 102 occurs.

Similarly, as shown in (B), even in the case where a gap is generated in the center of the clip holding area 101d, the film side edge 100a corresponding to this center portion is recessed toward the center side. Likewise, edge wrinkles 104 occur. The edge wrinkles 102 and 104 have a higher draw ratio, for example, in the case of (A), the stress at the time of stretching is concentrated in the gripping portion of the clip in which the gap is formed on one side, and the bite is taken as the starting point of the clip gripping portion. Tearing occurs. Also in the case of (B), bite tear occurs.

If biting tear occurs, the stretching of the portion is not sufficiently performed, and thus, unevenness may occur in the optically insufficient portion, which is not preferable. Moreover, the film 100 may be broken from the bite tear part, and in this case, it leads to drawing stop, which is a problem.

This invention is made | formed in order to solve the said subject, and an object of this invention is to provide the extending | stretching method, apparatus, and solution film forming method of a polymer film which suppressed generation | occurrence | production of an edge wrinkle with a simple structure.

In order to achieve the above object, the stretching method of the polymer film of the present invention stretches the polymer film at a predetermined magnification in the width direction by gripping both edges of the polymer film by an openable and open gripper moving in the running direction of the polymer film. In the stretching method of the polymer film, after holding the said polymer film with the said holding | gripping tool, the holding | gripping width of the said polymer film is gradually extended and extended | stretched below the said predetermined magnification, and the said shrinkage force of the stretched said polymer film is said, It is characterized by having a holding | maintenance process which stabilizes a grip by biasing a holding | gripping tool in the closing direction, and this extending process provided after the said holding | maintenance stabilization process, and extending | stretching at the said predetermined magnification by gradually increasing the holding width of the said polymer film, It is characterized by the above-mentioned. .

Moreover, it is preferable that the said holding | maintenance stabilization process starts extending | stretching within 10 second after holding | gripping the said polymer film by the said holding | gripping tool.

Moreover, it is preferable to have a conveyance process which maintains and hold | maintains the holding width of the said polymer film substantially constant between the said holding | maintenance stabilization process and the said main stretching process.

Moreover, the said polymer film is a cellulose acylate film in which a solvent remains, It is preferable to make the residual solvent amount of the said cellulose acylate film into 5% or more and 12.5% or less in the said holding | maintenance stabilization process and the said extending process.

Further, the cellulose acylate film has a film thickness of 70 µm or more and 110 µm or less before stretching, wherein the predetermined magnification is 130% or more and 140% or less, and the stretching magnification of the gripping stabilization step is 101.5% or more and 125% or less. It is preferable. Moreover, as for the draw ratio of the said holding | maintenance stabilization process, 101.5% or more and 110% or less are more preferable, and 101.5% or more and 105% or less are the most preferable.

In addition, the solution film forming method of the present invention casts a dope containing a polymer and a solvent on a support that runs endlessly, forms a cast film from the dope on the support, and peels off the gelled cast film from the support by cooling. And extending | stretching the said polymer film using the said flexible film peeled from the said support body as a polymer film, It is characterized by the above-mentioned.

Moreover, the extending | stretching apparatus of the polymer film of this invention extend | stretches the both sides of the said polymer film by the opening-closing holding | gripping tool which moves to the running direction of a polymer film, and extends the polymer film which extends the said polymer film at a predetermined magnification in the width direction. In the apparatus, after the polymer film is held by the gripping tool, the gripping width of the polymer film is gradually increased to extend below the predetermined magnification, and the gripper is closed by the contracting force of the stretched polymer film. And gripping stabilization means for biasing and stabilizing the gripping, and the main stretching means provided behind the gripping stabilization means and stretching at the predetermined magnification by gradually increasing the gripping width of the polymer film.

(Effects of the Invention)

According to the present invention, since the gripper is biased in the closing direction by the contracting force of the stretched polymer film to stabilize the grip, the gripping defect of the polymer film caused by the gripper can be prevented. Thereby, generation | occurrence | production of the edge wrinkle of a polymer film can be suppressed, and a polymer film can be reliably extended without unevenness.

1 is a plan view showing a clip tenter.

2 is a side view showing the clip.

3 is a perspective view of the clip, clip opener, and clip closure.

4 is a schematic view of a solution film production facility.

5 shows an example of a bite failure, (A) shows an example of one bite, and (B) shows an example in which the middle is missing.

(Explanation of the sign)

2: clip tenter

2a: preheating zone

2b: Phage stable zone

2c: width maintenance zone

2d: This stretch zone

2e: Elongation relief zone

3: polymer film

5: Clip (holding zone)

11: first rail

12: the second rail

72: flexible drum (support)

As shown in FIG. 1, the clip tenter 2 stretches in the film width direction B, holding both edge parts of the polymer film 3 with the clip (gripping tool) 5, and conveying it in the film conveyance direction (A). In addition, the polymer film 3 is dried.

The clip tenter 2 includes a first rail 11, a second rail 12, and first and second chains (endless chains) 13 and 14 guided to these rails 11 and 12. have.

The clip tenter 2 is arrange | positioned in the drying chamber not shown. The drying chamber is partitioned into the preheating zone 2a, the gripping stability zone 2b, the width maintaining zone 2c, the main stretching zone 2d, and the stretching relaxation zone 2e in the film conveying direction A. FIG. In the preheating zone 2a, the polymer film 3 is preheated at a predetermined temperature of, for example, 80 ° C. or more and 145 ° C. or less. In the preheating zone 2a and the width maintaining zone 2c, the distance between the pair of clips does not change, and stretching in the film width direction B by the clip 5 is not performed.

In the holding | maintenance stable zone 2b, the width retention zone 2c, and this extending | stretching zone 2d, the polymer film 3 is heated at 80 degreeC or more and 145 degrees C or less, for example. In the holding | maintenance stable zone 2b and this extending zone 2d, the distance between a pair of clips gradually increases, and the polymer film 3 is extended in the film width direction B by the clip 5. In the stretch relaxation zone 2e, the polymer film 3 is heated, for example at 80 ° C or more and 145 ° C or less, and the distance between the pair of clips is unchanged, or gradually decreases, thereby stretching relaxation.

In the gripping stable zone 2b, the residual solvent amount of the polymer film 3 is stretched in a state of 12%, and in the stretching zone 2d, the residual solvent amount of the polymer film 3 is stretched in a state of 10%. In addition, it is not limited to the said amount of residual solvent, In the holding | maintenance stable zone 2b and this extending | stretching zone 2d, it can change within the range of 5-12.5% of residual solvent amount. In addition, in this embodiment, the amount of residual solvent of the polymer film 3 shall show the amount of the solvent remaining in a film on a dry basis. The measurement method takes out a sample from the film of object, and computes it as {(x-y) / y} * 100, when making the weight of this sample x and the weight after drying a sample y.

A plurality of clips 5 are attached to the first and second chains 13 and 14 at regular intervals. The clip 5 extends the polymer film 3 in the film width direction B by moving along the rails 11 and 12 while holding the side edge portions of the polymer film 3. Moreover, in this embodiment, when the thickness of the polymer film 3 before extending | stretching is 70 micrometers and width is 100%, it extends so that the width after extending | stretching may be 140%, but it is not limited to this, A draw ratio is a desired optical characteristic. It changes suitably according to etc., and it is preferable that they are 130% or more and 140% or less.

The first and second chains 13 and 14 span between the prime sprockets 21 and 22 and the driven sprockets 23 and 24, and between these sprockets 21 to 24 the first chain 13 is the first one. By the rail 11, the second chain 14 is guided by the second rail 12. The prime sprockets 21 and 22 are provided on the tenter outlet 27 side, and they are rotationally driven by a drive mechanism (not shown), and the driven sprockets 23 and 24 are provided on the tenter inlet 26 side.

As shown in FIG. 2, the clip 5 is comprised from the clip main body 31 and the rail attachment part 32. As shown in FIG. The clip main body 31 is comprised from the substantially U-shaped frame 33 and the flapper 34, and the flapper 34 is rotatably attached to the frame 33 by the attachment shaft 33a. The flapper 34 rotates between the film gripping position that is approximately vertical (see FIG. 3) and the open position (see FIG. 2) where the engaging head 34a contacts the clip opener 40 and is in an oblique rotation. Usually, it is biased so that it may become a film holding position by its own weight. In the film holding start position PA, the polymer film 3 is gripped by the film holding surface 33b and the flapper lower surface 34b.

The rail attachment part 32 is comprised from the attachment frame 35 and the guide rollers 36,37,38. The attachment frame 35 is attached to the first chain 13 or the second chain 14. The guide rollers 36 to 38 rotate in contact with the support surfaces of the prime sprockets 21 and 22 or in contact with the support surfaces of the first rail 11 or the second rail 12. As a result, the clip main body 31 is guided along the rails 11 and 12 without falling off from the sprockets 21 and 22 and the rails 11 and 12.

As shown in FIG. 1, the clip opener 40 for opening the clip 5 near the sprockets 21-24 is arrange | positioned. As shown in FIG. 2, the clip opener 40 contacts the engaging head 34a of the clip 5 in front of the film holding start position PA at the driven sprockets 23 and 24 of the tenter inlet 26 and opens it. The side edge portion of the polymer film 3 can be accommodated. Then, when passing through the film holding start position PA, the clip opener 40 is separated from the engaging head 34a so that the clip 5 is set at the holding position from the open position by its own weight to the side of the polymer film 3. The edge is gripped. Similarly, in the sprocket 21, 22 of the tenter outlet 27, the clip 5 is brought into the open position by the clip opener 40 at the grip open position PB of the polymer film 3 so that the polymer film 3 can be opened. The grip of the side edge of the is opened.

In the clip tenter 2, the stretching of the polymer film 3 is started at the stretching start position PC (see FIG. 1), and the stretching of the polymer film 3 is finished at the stretching ending position PD. The polymer film 3 is conveyed without extending | stretching in the preheating zone 2a from film holding start position PA to extending | stretching start position PC. In addition, the polymer film 3 is conveyed without extending | stretching in the extending | stretching relaxation zone 2e from extending | stretching end position PD to the gripping opening position PB.

As shown in FIG. 1, between the extending | stretching start position PC and the extending | stretching pause position PE becomes the holding stability zone 2b, and is between the extending | stretching pause position PE and the extending | stretching resume position PF. It becomes the width retention zone 2c, and the extending | stretching zone 2d is from the extending | stretching restart position PF to the extending | stretching end position PD. The extending | stretching start position PC is provided in the position which the clip 5 which grasped the polymer film 3 reaches in 4 second after the film holding start position PA. The number of seconds is not limited to 4 seconds and can be changed as appropriate within 10 seconds.

In the holding | maintenance stable zone 2b, when the width | variety of the polymer film 3 before extending | stretching is 100%, it extends | stretches so that the width after extending | stretching may be 104%. As shown in FIG. 3, the shrinkage force generate | occur | produces in the original shape in the shrinkage direction C in the polymer film 3 extended in the width direction. The polymer film 3 is sandwiched between the film holding surface 33b and the flapper lower surface 3 (4b), and the clip 5 in which the polymer film 3 moves along the rail 11 by the contracting force in the shrinking direction C is provided. ), The flapper 34 is rotated clockwise, and in the case of the clip 5 moving along the rail 12, the flapper 34 is rotated counterclockwise so that the clips 5 are respectively closed. Biased in the direction. As a result, the holding force by the clip 5 is increased, and the film holding by the clip 5 is stabilized. In this embodiment, the 1st, 2nd rails 11 and 12 of the part of the holding | maintenance stabilization zone 2b function as a holding | gripping tool which stabilizes the holding | gripping by the clip 5. Moreover, the draw ratio in the holding | maintenance stable zone 2b changes suitably, It is preferable that they are 101.5% or more and 125% or less.

In the width maintenance zone 2c, the polymer film 3 is conveyed while maintaining the stretched state at 104%. For this reason, in the width maintenance zone 2c, the force which rotates the clip 5 to the closing direction by the contracting force of the polymer film 3 becomes larger than the holding | maintenance stability zone 2b, and the film holding by the clip 5 is further increased. It is stable.

In the stretching zone 2d, when the width of the polymer film 3 before stretching in the gripping stability zone 2b is 100%, the stretching is performed so that the width after stretching is 140% (predetermined magnification). When the width | variety of the polymer film 3 before extending | stretching in the holding | maintenance stable zone 2b is 100%, the polymer film 3 extended | stretched to 104% is conveyed to this extending | stretching zone 2d. That is, in this drawing zone 2d, when the polymer film 3 before stretching in the gripping stability zone 2b is 100%, the width of the polymer film 3 is stretched from 104% to 140%. In this embodiment, the 1st, 2nd rail 11 and 12 of the part of this drawing zone 2d function as this extending means which extends the polymer film 3 by 140% as a predetermined | prescribed magnification.

Next, the manufacturing method of the said polymer film 3 is demonstrated. However, the manufacturing method and manufacturing apparatus which are described below are an example of this invention, It is not limited to this.

[Solution forming method]

The schematic diagram of the solution film forming installation 50 used by this embodiment in FIG. 4 is shown. The solution film forming facility 50 includes a stock tank 51, a flexible chamber 52, a pin tenter 53, a clip tenter 2, a drying chamber 54, a cooling chamber 55, and a winding chamber 56.

The stock tank 51 is provided with the stirring blade 51b and the jacket 51c which rotate by the motor 51a, and the dope 61 used as a raw material of the polymer film 3 is stored inside. The dope 61 in the stock tank 51 is adjusted by the jacket 51c so that temperature may become substantially constant. In addition, the doping 61 is maintained at a uniform quality while the coagulation of the polymer or the like is suppressed by the rotation of the stirring blade 51b. Downstream of the stock tank 51, the gear pump 65 and the filtration apparatus 66 are provided, and the dope 61 is sent to the casting die 70 through these.

The casting chamber 52 is provided with a casting die 70, a casting drum 72, a peeling roller 74, temperature regulating devices 75 and 76, and a pressure reduction chamber 77. The casting drum 72 is rotated by a driving apparatus (not shown), and the dope 61 is discharged from the casting die 70 toward the circumferential surface 72b of the casting drum 72 during this rotation, thereby causing the casting drum. The flexible film 73 is formed in the circumferential surface 72b of the 72.

The casting chamber 52 and the casting drum 72 are set to a temperature at which the casting membrane 73 is easily gelled by the temperature regulating devices 75 and 76. And while the casting drum 72 rotates about 3/4, the casting film 73 reaches the gel strength which has self-support, and is peeled from the casting drum 72 by the peeling roller 74. As shown in FIG.

The pressure reduction chamber 77 is arrange | positioned with respect to the casting | dye die | dye 70 in the drum run direction upstream, and maintains the chamber 77 in negative pressure. This reduces the back side of the flexible bead (later, the surface in contact with the circumferential surface 72b of the flexible drum 72) to a desired pressure, thereby reducing the influence of the accompanying air generated by rotating the flexible drum 72 at high speed. A small amount of stable cast beads are formed between the cast die and the cast drum, and a cast film 73 with a small variation in film thickness is formed. And after the casting film 73 becomes self-supporting, the peeling roller 74 peels off the casting film on the casting drum 72 as a wet film 78.

The material of the flexible die 70 is formed of a material having high corrosion resistance and low thermal expansion coefficient with respect to a mixed electrolyte solution such as an aqueous electrolyte solution, dichloromethane or methanol. As for the finishing precision of the contact surface of the casting die 70, it is preferable to use 1 micrometer or less in surface roughness, and 1 micrometer / m or less of straightness in either direction.

The peripheral surface 72b of the casting drum 72 is subjected to chromium plating to have sufficient corrosion resistance and strength. In addition, the temperature regulating device 76 circulates the heat transfer medium in the casting drum 72 in order to maintain the temperature of the peripheral surface 72b of the casting drum 72 at a desired temperature. The heat transfer medium is maintained at a desired temperature, and by passing through the heat transfer medium flow path in the casting drum 72, the temperature of the circumferential surface 72b of the casting drum 72 is maintained at the desired temperature.

Although the width | variety of the casting drum 72 is not specifically limited, It is preferable to use the thing of the range of 1.1 times-2.0 times the casting width of dope. It is preferable that the material of the casting drum 72 is stainless steel, and it is more preferable that it is made of SUS316 so that it may have sufficient corrosion resistance and strength. It is preferable that the chromium plating process performed on the peripheral surface 72b of the casting drum 72 is Vickers hardness Hv700 or more, film thickness of 2 micrometers or more, what is called hard chromium plating.

In the flexible chamber 52, a condenser (condenser) 79 for condensing and recovering the evaporated organic solvent and a recovery device 80 for recovering the condensed liquefied solvent are provided. The organic solvent condensed and liquefied in the condenser 79 is recovered by the recovery device 80. The solvent is recycled in the regeneration apparatus and then reused as a solvent for dope preparation.

Downstream of the flexible chamber 52, the moving part 81, the pin tenter 53, and the clip tenter 2 are provided in order. The moving part 81 introduces the wet film 78 peeled by the conveyance roller 82 into the pin tenter 53. As shown in FIG. The pin tenter 53 has a plurality of pin plates that hold both ends of the wet film 78, and the pin plates travel on the track. During this run, dry wind is sent to the wet film 78 so that the wet film 78 is dried while traveling to form the polymer film 3.

The desired optical characteristic is imparted to the polymer film 3 which exited the clip tenter 2 by the stretching treatment under the predetermined conditions in the clip tenter 2. In addition, provision of the optical characteristic to the polymer film 3 may be performed offline after winding up the polymer film 3, and in this case, the clip tenter 2 may be omitted from the solution film-forming installation 50.

The edge cutting device 83 is provided downstream of the pin tenter 53 and the clip tenter 2, respectively. The edge cutting device 83 cuts the edge which is both ends of a film. This cut edge is sent to the crusher 84 by blowing, and it is pulverized here and recycled as raw materials, such as dope.

A plurality of rollers 87 are provided in the drying chamber 54, and drying is performed by winding the polymer film 3 around them and transporting them. An adsorption recovery apparatus 88 is connected to the drying chamber 54, and the solvent evaporated from the polymer film 3 is recovered by adsorption.

The cooling chamber 55 is provided in the exit side of the drying chamber 54, and is cooled in this cooling chamber 55 until the polymer film 3 turns to room temperature. Downstream of the cooling chamber 55, a forced static elimination device (antistatic bar) 89 is provided so that the polymer film 3 is statically charged. Moreover, the knurling provision roller 90 is provided in the downstream of the forced static elimination device 89, and a knurling is provided in the both edge part of the polymer film 3. As shown in FIG. In the winding chamber 56, the winding machine 91 which has the press roller 92 is provided, and the polymer film 3 is wound by the winding core in roll shape.

Next, an example of the method of manufacturing the polymer film 3 by the solution film-forming installation 50 is demonstrated. In the stock tank 51, the temperature of the dope 61 is adjusted to 25-35 degreeC by making a heat transfer medium flow inside the jacket 51c, and it is always uniformized by the rotation of the stirring blade 51b. An appropriate amount of dope 61 is sent from the stock tank 51 to the filtration device 66 by the gear pump 65 and filtered to remove impurities in the dope 61. Then, the dope 61 is cast on the circumferential surface 72b of the cast drum 72 cooled to a predetermined surface temperature while forming cast beads from the cast die 70. It is preferable that the temperature of the dope 61 at the time of casting | maintenance is kept substantially constant in the range of 30-35 degreeC.

The flexible drum (support) 72 is rotated about the axis 72a by the drive apparatus. By this rotation, the circumferential surface 72b is traveling at a constant speed (30 m / min or more and 200 m / min or less) in the direction Z1. Moreover, the temperature of the circumferential surface 72b of the casting drum 72 is adjusted so that it may become substantially constant in the range of -10-10 degreeC. By using the cooled drum 72 cooled in this manner, the flexible membrane 73 can be gelled to provide self-supportability. Moreover, management of the temperature of the circumferential surface 72b is performed by the temperature control device 76, and maintains the temperature of the circumferential surface 72b of the casting drum 72 at a predetermined value. As cooling of the casting film 73 proceeds, a crosslinking point serving as a base of the crystal is formed to promote gelation of the casting film 73.

After the flexible film 73 becomes self-supporting by the progress of gelation, it peels from the casting drum 72 by the peeling roller 74, and turns into the wet film 78, and conveys this wet film 78 It feeds to the pin tenter 53 by the roller 82.

The internal temperature of the flexible chamber 52 is adjusted so that it may become substantially constant in the range of 10-57 degreeC by the temperature control apparatus 75. FIG. Inside the casting chamber 52, the solvent in the casting dope 61 and the casting film 73 which are cast is volatilized, and it floats. Therefore, in this embodiment, after condensing and liquefying this floating solvent with the condenser 79, it collect | recovers with the collection | recovery apparatus 80, regenerates with a regeneration apparatus, and recycles it as a dope preparation solvent.

In the pin tenter 53, a plurality of pins are fixed by being plugged at both side ends of the wet film 78, and then drying is promoted to convey the wet film 78 to the polymer film 3. And the polymer film 3 of the state which still contains a solvent is sent to the clip tenter 2. At this time, it is preferable that the amount of residual solvent of the polymer film 3 just before being sent to the clip tenter 2 is 50 to 150 weight%.

In the clip tenter 2, the polymer film 3 is stretched in the width direction. Thus, the molecule | numerator in the polymer film 3 is orientated by the extending | stretching process to the width direction of the polymer film 3, and a desired retardation value can be provided to the polymer film 3.

The polymer film 3 having emerged from the pin tenter 53 and the clip tenter 2 is cut at both sides by the edge cutting device 83. The polymer film 3 whose both ends are cut is wound up by the winding machine 91 in the winding chamber 56 via the drying chamber 54 and the cooling chamber 55. In addition, both side ends cut by the edge cutting device 83 are crushed by the crusher 84 to be used as chips for dope preparation.

It is preferable that the polymer film 3 wound up by the winding machine 91 shall be at least 100 m or more in a longitudinal direction (flexion direction). Moreover, it is preferable that the width | variety of the polymer film 3 is 600 mm or more, and it is 1400 mm or more and 3000 mm or less, and it is more preferable that they are 1700 mm or more and 2100 mm or less. In addition, the present invention is effective even if the width is wider than 3000mm. Moreover, this invention is effective when manufacturing the thin film whose polymer thickness of the polymer film 3 is 110 micrometers or less.

The present invention can also be applied to a method for forming a solution using a flexible band wound around a rotating drum instead of the flexible drum 72. Also in this case, as a method of imparting self-supportability to the flexible film, drying may be performed by spraying dry air in addition to cooling gelation. When providing self-supportability to the film on a support body by drying, the pin tenter 53 is abbreviate | omitted and it dries with the clip tenter 2.

Hereinafter, the raw material used when preparing the dope 61 in this invention is demonstrated.

In this embodiment, cellulose acylate is used as a polymer, and cellulose triacetate (TAC) is particularly preferable as the cellulose acylate. And it is more preferable that the substitution degree of the acyl group to the hydroxyl group of a cellulose satisfy | fills all of following formula (I)-(II) also in a cellulose acylate. In the following formulas (I) to (III), A and B represent a degree of substitution of an acyl group with respect to a hydrogen atom in the hydroxyl group of cellulose, A is a degree of substitution of an acetyl group, and B has 3 carbon atoms It is substitution degree of the acyl group which is -22. Moreover, it is preferable that 90 weight% or more of TAC is 0.1-4 mm particle | grains. However, the polymer which can be used for this invention is not limited to a cellulose acylate.

(I) 2.5≤A + B≤3.0

(II) 0≤A≤3.0

(III) 0 ≦ B ≦ 2.9

The glucose units bound to β-1,4 constituting the cellulose have hydroxyl groups liberated at 2-position, 3-position and 6-position. Cellulose acylate is a polymer (polymer) in which some or all of these hydroxyl groups are esterified by acyl groups having 2 or more carbon atoms. Acyl substitution degree means the ratio (the substitution degree 1 is the case of 100% esterification) in which the hydroxyl group of a cellulose is esterified about 2, 3, and 6 positions, respectively.

As for the total acylation substitution degree, ie, the value of DS2 + DS3 + DS6, 2.00-3.00 are preferable, More preferably, it is 2.22-2.90, Especially preferably, it is 2.40-2.88. The value of DS6 / (DS2 + DS3 + DS6) is preferably 0.28 or more, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. Here DS2 is the ratio (henceforth the acyl substitution degree of 2-position) in the hydrogen of the 2-position hydroxyl group in a glucose unit is called the acyl substitution degree of 2 position, DS3 is the hydrogen of the 3-position hydroxyl group in a glucose unit Is the ratio substituted by the acyl group (henceforth 3-position acyl substitution degree), DS6 is the ratio in which the hydrogen of the 6-position hydroxyl group is substituted by the acyl group (henceforth 6-position acyl in a glucose unit). Called degree of substitution).

Only one kind of acyl group may be used for the cellulose acylate of the present invention, or two or more kinds of acyl groups may be used. When using two or more types of acyl groups, it is preferable that one is an acetyl group. The total amount of hydroxyl groups at the 2, 3, and 6 positions is substituted by the acetyl group, and the total amount of hydroxyl groups at the 2, 3, and 6 positions is substituted by the acyl groups other than the acetyl group. In the case of DSB, the value of DSA + DSB is preferably 2.22 to 2.90, particularly preferably 2.40 to 2.88.

Moreover, it is preferable that DSB is 0.30 or more, Especially preferably, it is 0.7 or more. Moreover, it is preferable that 20% or more of DSB is a substituent of a 6-position hydroxyl group, More preferably, it is 25% or more, More preferably, 30% or more is especially 33% or more. Moreover, the value of DSA + DSB in the 6-position of a cellulose acylate is 0.75 or more, More preferably, it is 0.80 or more, Especially the cellulose acylate of 0.85 or more is also preferable, and it is excellent in solubility by using these cellulose acylates. You can make dope. In particular, when a non-chlorinated organic solvent is used, dope which exhibits excellent solubility and excellent filterability at low viscosity can be produced.

The cellulose which is a raw material of cellulose acylate may be obtained from any one of a linter and a pulp.

The acyl group having 2 or more carbon atoms of the cellulose acylate in the present invention may be an aliphatic group or an aryl group, and is not particularly limited. For example, alkyl carbonyl ester, alkenyl carbonyl ester, aromatic carbonyl ester, aromatic alkyl carbonyl ester of cellulose, etc. are mentioned, You may have a further substituted group, respectively. As these preferable examples, a propionyl group, butanoyl group, pentanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, iso -Butanoyl group, t-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group, etc. are mentioned. Among these, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, t-butanoyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group, and the like are more preferable, and particularly preferably propionyl group Butanoyl group.

As a solvent for preparing the dope, an aromatic hydrocarbon (for example, benzene, toluene, etc.), a halogenated hydrocarbon (for example, dichloromethane, chlorobenzene, etc.), an alcohol (for example, methanol, ethanol, n-propanol, n-butanol, Diethylene glycol, etc.), ketones (e.g. acetone, methyl ethyl ketone, etc.), esters (e.g. methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (e.g. tetrahydrofuran, methylcellosolve Etc.) can be mentioned.

Among the halogenated hydrocarbons, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. From the viewpoints of physical properties such as solubility of TAC, peelability from the support of the flexible membrane, mechanical strength and optical properties of the film, it is preferable to mix one or several kinds of alcohols having 1 to 5 carbon atoms in addition to dichloromethane. As for content of alcohol, 2-25 weight% is preferable with respect to the whole solvent, More preferably, it is 5-20 weight%. Examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, and the like, but methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

In recent years, the preparation of a solvent which does not use dichloromethane for the purpose of minimizing the influence on the environment is also examined. In this case, ethers having 4 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and alcohols having 1 to 12 carbon atoms are preferable, and these may be appropriately mixed. have. For example, a mixed solvent of methyl acetate, acetone, ethanol and n-butanol can be mentioned. These ethers, ketones, esters and alcohols may have a cyclic structure. Moreover, the compound which has two or more of functional groups of ether, ketone, ester, and alcohol (namely, -O-, -CO-, -CO0-, and -OH) can also be used as a solvent.

Details of the cellulose acylate are described in paragraphs [0195] of the Japanese Patent Laid-Open No. 2005-104148, and these descriptions can also be applied to the present invention. [0196] Similarly, additives such as solvents and plasticizers, anti-degradants, ultraviolet absorbers (UV agents), optically anisotropic control agents, retardation control agents, dyes, matting agents, peeling agents, and peeling accelerators are similarly disclosed in Japanese Patent Application Laid-Open No. 2005-104148. The paragraphs are described in detail in the paragraphs, and these descriptions can also be applied to the present invention.

In the solution film forming method of the present invention, when the dope is cast, simultaneous lamination co-bonding in which two or more types of dopes are cast and laminated at the same time, or sequential lamination co-bonding in which a plurality of dope are sequentially co-coated and laminated can be performed. In addition, you may combine both covalent bonds. When performing simultaneous lamination sharing, a flexible die with a feed block may be used, or a multi-manifold type flexible die may be used. However, it is preferable that at least one of the thickness of the layer of an air plane side, and the thickness of the layer of a support body side is 0.5-30% of the film thickness in the film which consists of multilayers by covalent edge. In the case of performing simultaneous lamination co-bonding, when the dope is cast from the die slit to the support, it is preferable that the high-viscosity dope is wrapped by the low-viscosity dope, and the dope in contact with the outer space among the flexible beads formed from the die slit over the support. It is preferable that the composition ratio of alcohol is larger than internal dope.

Japanese Patent Laid-Open Patent Publication No. 2005-104148 from structures such as casting dies, pressure reducing chambers, supports, covalent lead, peeling, stretching, drying conditions of each step, handling methods, curling, winding after planarity correction, solvent recovery methods, and film recovery methods. Paragraphs [0617] to [0889] are described in detail, and their description is also applicable to the present invention.

Example 1

[Film production]

In the solution film-forming installation 50 shown in FIG. 4, chromium plating and mirror-mirror processing are given to the surface, and thickness 70 micrometers before extending | stretching dope 61 on the surface of the cylindrical casting drum 72 of diameter 1000mm. The flexible film 73 was formed by being flexible. It peeled, supporting the flexible film 73 which has self-supportability with the peeling roller 74, and obtained the wet film 78. FIG.

In the pin tenter 53, pins were held at both side ends of the wet film 78 near the inlet, and the wet film 78 was dried to obtain a polymer film (TAC film) 3. Subsequently, it is sent to the clip tenter 2, and the preheating zone 2a, the gripping stability zone 2b, and the width holding zone 2c of which drying temperature is 120 degreeC is carried out, maintaining both ends of the polymer film 3 with the clip 5, and so on. ) It was sent to the stretching zone 2d and the stretching relaxation zone 2e to preheat, stretch, and relax.

When the width | variety of the polymer film 3 before extending | stretching was 100%, the draw ratio in the gripping stability zone 2b was 104.7%, and the draw ratio in this stretch zone 2d was 140%. In the gripping stable zone 2b, the polymer film 3 was stretched to 12% of the residual solvent, and in the stretching zone 2d, it was stretched to 10% of the residual solvent.

After cutting both side ends of the polymer film 3 with the edge cutting device 83 provided downstream of the clip tenter 2, the polymer is wound around the plurality of rollers 87 in the drying chamber 54 and then transported. The drying of the film 3 was fully promoted. After cooling the polymer film 3 to approximately room temperature in the cooling chamber 55, it is sent to the winding chamber 56, wound on a winding core while pressing with a press roller 92, and rolled polymer film 3 ) Moreover, before winding up, the strong voltage was adjusted by the forced static elimination device 89, and the knurling provision roller 90 provided the knurling.

[Dope]

The raw material of the dope used in Example 1 is as follows.

Cellulose triacetate… 100 parts by weight

Dichloromethane… 320 parts by weight

Methanol… 83 parts by weight

1-butanol... 3 parts by weight

Plasticizer A 7.6 parts by weight

Plasticizer B 3.8 parts by weight

UV agent a... 0.7 parts by weight

UV b ... 0.3 parts by weight

Fine particles… 0.05 parts by weight

The cellulose triacetate is a powder having a substitution degree of 2.84, a viscosity average degree of polymerization of 306, a water content of 0.2% by weight, a viscosity of 6% by weight in a dichloromethane solution of 315 mPa · s, an average particle diameter of 1.5 mm, and a standard deviation of 0.5 mm. Triphenylphosphate, plasticizer B is diphenylphosphate, UV agent a is 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, UV agent b is 2 (2') -Hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, the citric acid ester compound is a mixture of citric acid, monoethyl ester, diethyl ester and triethyl ester, and the fine particles have an average particle diameter This is 15 nm and silicon dioxide whose Mohs' Hardness is about 7.

In Example 1, when the film thickness before extending | stretching of the polymer film 3 which is a TAC film is made into 70 micrometers, and the width | variety of the polymer film 3 before extending | stretching is made into 100%, the draw ratio in the holding | maintenance stability zone 2b. Silver 104.7% and the draw ratio in this drawing zone 2d was 140%. The film holding stability of the clip 5 in this drawing zone 2d at that time was observed with a television camera, and when there was a tearing of the film by visual observation, x when there was a film omission, ○ Hereinafter, about Example 1, Examples 2-5 and Comparative Examples 1 and 2 were obtained by changing the film thickness before extending | stretching and the draw ratio in the holding | maintenance stable zone 2b. Other film production conditions were the same as in Example 1. The results of this experiment are shown in Table 1.

Table 1

As a result of this experiment, the film holding stability was favorable in Examples 1-5. Moreover, in Comparative Examples 1 and 2, the tearing of the film or the dropping of the film occurred, resulting in poor film holding stability. Moreover, the same result was obtained when the holding | maintenance stable zone 2b and this extending | stretching zone were directly connected, without providing the width maintenance zone 2c.

As described above, since the grip of the clip 5 is stabilized by biasing the clip 5 in the closing direction by the contracting force of the polymer film 3 in the gripping stability zone 2b, the film is torn and missing. The film can be stably held in the drawing zone 2d without this. Thereby, the polymer film 3 can be reliably stretched even if the film thickness before stretching is thin (for example, 70 micrometers) or the high draw ratio (for example, 130 to 140%), and an edge is obtained. It is possible to produce a polymer film 3 free of wrinkles and stretching unevenness.

Moreover, since the width | variety holding zone 2c was provided between the holding | maintenance stable zone 2b and this extending | stretching zone 2d, a film can be hold | maintained more stably in this drawing zone 2d more reliably.

Claims (7)

A stretching method of a polymer film, wherein the polymer film is stretched at a predetermined magnification in a width direction by gripping both edges of the polymer film by an openable and open gripper moving in the running direction of the polymer film. After gripping the polymer film by the gripping hole, the gripping width of the polymer film is gradually increased to draw below the predetermined magnification, and the gripping hole is biased in the closing direction by the contracting force of the stretched polymer film. A phage stabilization step of stabilizing phage; And It is provided after the said holding | maintenance stabilization process, and has the this extending process which extends | stretches at the said predetermined magnification by gradually increasing the holding width of the said polymer film, The extending | stretching method of the polymer film characterized by the above-mentioned. The method for stretching a polymer film according to claim 1, wherein the gripping stabilization process starts stretching within 10 seconds after gripping the polymer film by the gripping tool. The extending | stretching method of the polymer film of Claim 1 or 2 which has a conveyance process which keeps and conveys the holding width of the said polymer film substantially constant between the said holding | maintenance stabilization process and the said main stretching process. The method of any one of claims 1 to 3, wherein the polymer film is a cellulose acylate film in which a solvent remains, In the said holding | maintenance stabilization process and the said extending | stretching process, the residual solvent amount of the said cellulose acylate film was made into 5% or more and 12.5% or less, The extending | stretching method of the polymer film characterized by the above-mentioned. The said cellulose acylate film is a film thickness before extending | stretching 70 micrometers or more and 110 micrometers or less, The said predetermined magnification is made into 130% or more and 140% or less, and the draw ratio of the said gripping stabilization process is 101.5% or more and 125. The stretching method of the polymer film characterized by the below-mentioned. The dope containing the polymer and the solvent were casted on an endless running support, A flexible film is formed from the dope on the support, The said flexible film gelled by cooling is peeled from the said support body, The film forming method of the polymer film as described in any one of Claims 1-5 is performed using the said flexible film peeled from the said support body as a polymer film. In the stretching apparatus of the polymer film which grips both edge parts of the said polymer film by the opening-closing holding | gripping tool which moves to the running direction of a polymer film, and extends the said polymer film by the predetermined magnification in the width direction: After gripping the polymer film by the gripping hole, the gripping width of the polymer film is gradually increased to draw below the predetermined magnification, and the gripping hole is biased in the closing direction by the contracting force of the stretched polymer film. Gripping stabilization means for stabilizing gripping; It is provided behind the said holding | maintenance stabilization means, The extending | stretching apparatus of the polymer film provided with this extending means which extends | stretches at the said predetermined magnification by gradually increasing the holding width of the said polymer film.