JPWO2012114820A1 - Film manufacturing method and film manufacturing apparatus - Google Patents

Abstract

It is intended to provide a film production method and production apparatus using a solution casting film forming method capable of improving the optical properties of the film. In order to achieve this object, a thermoplastic resin solution is cast on the surface of a support to form a cast film, and the cast film is solidified on the surface of the support, and then the surface of the support is formed. A web is formed by peeling from the web, and the web is dried and then stretched, and the stretched web is further dried. Here, in the step of drying the former web, a portion including the vicinity of both ends except for the central portion of the web at least in the short direction by the driving roll in a state where the content of the solvent in the web is 5% by weight or more. The web is conveyed in the longitudinal direction while being sucked and / or pinched. And the drive roll has the surface of the mirror surface state which contacts the center part of a web.

Description

  The present invention relates to a film manufacturing technique using a solution casting film forming method.

  In recent years, films using thermoplastic resins (also referred to as thermoplastic resins) have been used in liquid crystal display devices and the like that are widely spread. As a film forming method using a thermoplastic resin, a highly productive film forming method such as a solution casting film forming method is known.

  In a film manufacturing method using the solution casting film forming method, a thermoplastic resin solution (also referred to as a thermoplastic resin solution or a dope) is used as a raw material for manufacturing the film. The dope is cast from the casting die to the surface (also referred to as the support surface) of the metal support (also referred to as the support) made of a metal or an alloy to form a cast film of thermoplastic resin. The In the present invention, a film that is cast from a casting die onto a support and peeled off from the support is expressed as a casting film. The cast film is cooled and dried to some extent and then peeled off from the support to form a web. The film is manufactured by appropriately drying, stretching, cooling, and the like on the web and then winding the web with a winder. In the present invention, the film peeled from the support is expressed as a web, and the wound film is expressed as a film.

  In this film manufacturing method, a tension in the conveyance direction (also referred to as MD tension) is applied to the web from the support to the winder. The purpose of the web is to smoothly convey the web and to adjust the MD tension applied to the web. The web is reliably conveyed by the driving force while holding the web by suction (suction) and / or nipping (nip). A roll (also called a drive roll or a feed roll) is provided as appropriate.

  By the reliable conveyance of the web by the driving roll, the web can be conveyed at high speed, and as a result, the production speed of the film can be increased. Moreover, MD tension of the web in the process before and behind this drive roll can be interrupted by the drive roll, and the MD tension of the web can be adjusted to a desired tension.

  And about the drive roll, the suction roll in which the suction port has comprised the slit shape continuous over the range which does not exceed the width | variety of a web in the width direction of a roll is proposed (for example, patent document 1 etc.). . Thereby, the surface property of the web is not impaired, and a stable quality film can be obtained by stably transporting the web without wrinkles and / or creases.

  In addition, in the web drying process, a technique has been proposed in which web scratches caused by threading with the suction roll are suppressed by adjusting the surface temperature of the suction roll and the temperature of the web (for example, Patent Document 2).

  In addition, a suction roller is proposed in which the suction width is adjusted according to the width of the web and dust is prevented from scattering (for example, Patent Document 3).

  Furthermore, a technique has been proposed in which the occurrence of scratches on the web is suppressed by adjusting the diameter of the suction holes provided in the suction roller and chamfering (for example, Patent Document 4).

Japanese Patent Laid-Open No. 08-133536 JP 2002-194107 A Japanese Patent Laid-Open No. 2003-072997 JP 2006-297888 A

  However, in the techniques of Patent Documents 1 to 4, since many suction ports are provided over the entire surface of the suction roll in contact with the web, the surface of the web is scratched by rubbing with the many suction ports. Will be attached. In addition, Patent Document 2 suggests that if a press roll is used in order to avoid scratches caused by rubbing with a large number of suction ports, a fatal failure such as a press wound is likely to occur on the surface of the web, which is not preferable. Has been. Therefore, a technique for improving the optical characteristics of the film is desired in the film manufacturing technique using the solution casting film forming method.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a film manufacturing method and a film manufacturing apparatus using a solution casting film forming method capable of improving the optical properties of the film. And

  In order to solve the above-mentioned problem, a method for producing a film according to a first aspect includes: (a) a film in a solution casting film forming method on a surface of a support composed of a metal or an alloy; A step of forming a cast film by casting a thermoplastic resin solution as a raw material; and (b) a step of solidifying the cast film formed in the step (a) on the surface of the support. (C) peeling the film solidified in the step (b) from the surface of the support to form a web; and (d) drying the web formed in the step (c). And (e) stretching the web dried in the step (d), and (f) drying the web stretched in the step (e). In the film production method, in the step (d), with the solvent content in the web being 5% by weight or more, the driving roll removes at least the central portion of the web in the short direction. And while sucking and / or pinching the portion including the vicinity of both ends, the web is conveyed in the longitudinal direction of the web perpendicular to the short direction, and the driving roll is in a mirror surface state in contact with the central portion. Having a surface.

  The method for producing a film according to the second aspect is the method for producing a film according to the first aspect, wherein the driving roll has a first rotation axis parallel to the short direction of the web, and the first A first holding part that sucks and / or pinches the web provided on one end side along the rotation axis, and is provided on the other end side opposite to the one end side along the first rotation axis. A second holding portion that sucks and / or pinches the web, and in the driving roll, a first separation distance between the first holding portion and the second holding portion is W1, and the web When the width in the lateral direction is W2, the relationship of 0.97 ≧ W1 / W2 ≧ 0.90 is satisfied.

  The manufacturing method of the film which concerns on a 3rd aspect is a manufacturing method of the film which concerns on a 1st or 2nd aspect, Comprising: The said drive roll contains a suction roll.

  The film manufacturing method according to the fourth aspect is the film manufacturing method according to any one of the first to third aspects, wherein the driving roll sandwiches the web between the pressing roll. Includes roles.

  The film manufacturing method according to the fifth aspect is the film manufacturing method according to any one of the first to fourth aspects, wherein the web is conveyed by the two or more driving rolls in the step (d). To do.

  The film manufacturing method according to the sixth aspect is the film manufacturing method according to the fifth aspect, wherein the first separation distance of the drive roll is gradually increased in the order in which the web contacts in the step (d). Or shortened step by step.

  A film manufacturing method according to a seventh aspect is the film manufacturing method according to any one of the first to sixth aspects, wherein in the step (d), the web is not driven and is not driven The non-driving rolls are conveyed while sequentially contacting the rolls, and each non-driving roll comes into contact with a second rotating shaft parallel to the short direction of the web and the vicinity of both ends of the web in the short direction. 1 and a second non-mirror surface portion, and the first non-mirror surface portion is provided on the first end side along the second rotation axis of each of the non-driving rolls, and the second non-mirror surface portion A first end portion of the first non-specular surface portion is provided on a second end side opposite to the first end side along the second rotation axis of each of the non-driving rolls. The second separation distance between the outer edge on the side and the outer edge on the second end side of the second non-specular surface portion is the step (d). In the order of the non-driven roll which the web is in contact you are, gradually or stepwise shorter.

  The film manufacturing apparatus according to the eighth aspect is configured by using a metal or an alloy, and is cast by casting a thermoplastic resin solution that is a raw material of the film in the solution casting film forming method on the surface. A support for forming a film, the cast film solidified on the surface was peeled off, a web was formed, and the web was dried, and the first drying area was dried by the first drying area A stretching section for stretching the web; and a second drying region section for drying the web stretched by the stretching section. The film manufacturing apparatus is configured such that the first drying region portion sucks and / or clamps a portion of the web excluding at least a central portion in a short direction and including the vicinity of both end portions. Is driven in the longitudinal direction of the web perpendicular to the short direction, and the drive roll has a mirror-finished surface in contact with the central portion.

  The film production method according to any one of the first to seventh aspects also suppresses the occurrence of scratches and deformations in the web, so that the optical properties of the film are improved.

  According to the method for producing a film according to the second aspect, an improvement in the optical properties of the film and an improvement in the production speed by high-speed web conveyance are achieved.

  According to the film manufacturing method of the fifth aspect, since the tension acts stably in the transverse direction of the web in the drying step, the optical properties of the film are further improved.

  According to the film manufacturing method of the sixth aspect, since a stable tension acts in the short direction of the web in the drying step, the optical characteristics of the film are further improved.

  According to the manufacturing method of the film which concerns on a 7th aspect, the stable conveyance of a web and the improvement of the optical characteristic of a web are achieved.

  According to the film manufacturing apparatus of the eighth aspect, since the occurrence of scratches and deformation in the web is suppressed, the optical characteristics of the film are improved.

Drawing 1 is a mimetic diagram showing the film manufacture device concerning a 1st embodiment. FIG. 2 is a schematic diagram illustrating a configuration example of the first drying zone. FIG. 3 is a schematic diagram illustrating a configuration example of the drive roll. FIG. 4 is a schematic diagram showing a modification of the drive roll. FIG. 5 is a schematic diagram illustrating a configuration example of a non-driving roll. FIG. 6 is a schematic view showing a film manufacturing apparatus according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, parts having the same configuration and function are denoted by the same reference numerals, and redundant description is omitted in the following description. Further, the drawings are schematically shown, and the sizes, positional relationships, and the like of various structures in the drawings are not accurately illustrated. Further, for the purpose of clarifying the azimuth relationship of each figure, the coordinate axes of the right-handed XYZ orthogonal coordinate system are attached to FIGS.

<(1) Outline of measures for improving optical properties of film>
In a general film production method using a solution casting film forming method, a thermoplastic resin solution (dope) is cast on the surface of a metal support (also simply referred to as a support) (also referred to as a support surface). The casting film is formed, the casting film is peeled from the support surface to form a web (also referred to as a peeling process), and the web is dried (also referred to as a first drying process). ), A step in which the web is stretched in the short direction (that is, the width direction) (also referred to as a stretching step), a step in which the web is dried (also referred to as a second drying step), a web is wound, A process to be formed (also referred to as a winding process) is sequentially performed. Note that the direction in which the web is stretched in the stretching step may include, for example, a longitudinal direction and an oblique direction in addition to the lateral direction.

  Here, in the first drying step, for example, the solvent remains in the web, and the drive roll is in a state where the content (also referred to as residual solvent ratio) of the solvent (also referred to as residual solvent) in the web is 5% by weight or more. The web is conveyed by. At this time, the web is transported in the longitudinal direction perpendicular to the width direction while the drive roll excluding the central portion in the width direction and including the vicinity of the end in the width direction is sucked and / or pinched. . And the surface of the part which contacts the center part of the width direction of a web among this drive roll is made into the mirror surface state.

  With such a configuration, the web is less likely to be damaged at the center in the width direction. As a result, the optical properties of the film are improved.

<(2) First Embodiment of Film Manufacturing Apparatus>
<(2-1) Outline of Film Manufacturing Apparatus>
FIG. 1 is a schematic diagram of a film manufacturing apparatus 100 according to the first embodiment. In the film manufacturing apparatus 100, the film is manufactured using the solution casting film forming method.

  As shown in FIG. 1, a film manufacturing apparatus 100 includes a first drum 102, a second drum 104, an endless belt 106, a peeling roll 108, a first drying zone 110, a tenter 112, a second drying zone 114, and a winder. 116, a casting die 118, and a dope supply mechanism 120 are provided.

  The casting die 118 is close to and faces the outer surface (also referred to as a belt outer surface) 130 of the endless belt 106. The endless belt 106 is an example of a metal support 500, and the belt outer surface 130 is an example of a support surface 502.

In the film manufacturing apparatus 100, when the film _FOP is manufactured, the first and second drums 102 and 104 rotate, so that the endless belt 106 looped around the first and second drums 102 and 104 circulates. The outer surface 130 travels in the vicinity of the casting die 118. At this time, the doped doped supplying mechanism 120 to the casting die 118 is supplied, casting film from the casting die 118 doped been doped cast against the belt outer surface 130 on the belt outer surface 130 F _C Is formed.

Here, of the belt outer surface 130 of the support surface 502, (also referred to as a first _section) interval along the casting position _{P A} in the running direction of the belt outer surface 130 reaches the peeling position _{P B} in _{R AB,} doped casting film _{F C} is formed. Incidentally, the casting position _{P A,} of the belt outer surface 130, a position where the dope is cast by the casting die 118, the peeling position _{P B} is the casting film _{F C} is peeled from the belt outer surface 130 located It is. The temperature in the first section _RAB of the belt outer surface 130 is adjusted by a temperature adjusting device including a heater or the like.

Casting film F _C is dried and solidified on the belt outer surface 130, is peeled off from the belt outer surface 130, the web is formed. The peeled web F _C includes a further drying in the first drying zone 110 (first drying), and stretching in the tenter 112, further dried (second drying) in the second drying zone 114 Are sequentially applied and wound by the winder 116. Thus, a roll of the film _{F OP} is produced. The contents of the processing for a web F _C peeled from the belt outer surface 130 is modified as necessary.

<(2-2) Measures for improving optical properties of film in first drying>
<(2-2-1) Configuration of the first drying zone>
FIG. 2 is a schematic diagram illustrating a configuration example of the first drying zone 110.

As shown in FIG. 2, the first drying zone 110 includes a box-shaped drying device main body Db1, and the drying chamber Dr1 in the drying device main body Db1 includes N n-th driving rolls FRn and M M-th non-driving roll Rm is arranged. Here, N and M are arbitrary natural numbers, n is a natural number equal to or less than N, and m is a natural number equal to or less than M. In FIG. 2, when N = 5 and M = 46, that is, one configuration in which the first to fifth drive rolls FR1 to FR5 and the first to 46 non-drive rolls R1 to R46 are arranged in the first drying zone 110. Is illustrated. Hereinafter, this one configuration will be described as an example. Although are not shown, the front of each drive roll FRn, web F _C is a device for controlling the tension (also referred to as transport tension) applied to the web F _C when to be transported ( A tension control device).

Here, from the viewpoint of the amount of the desired amount of residual solvent in the web F _C in the first drying zone 110, and the number of the m non-driven roll Rm, and the length of a section in which the first m undriven roll Rm provided It only has to be set. Further, the number of the n-th driving roll FRn may be set to the number corresponding to the length of the path for transporting the web F _C, the n-th driving roll FRn, the setting of the tension applied to the web F _C Should be installed in each section.

In the first drying zone 110, the web _{F C} is carried into the drying chamber Dr1 from upstream is drying apparatus one end of the body Db1 transport path (in FIG. 2 -X side). Then, the web F _C is dried while being conveyed by the first m undriven roll R1m of the n drive roll FRn and the M arranged in the drying chamber Dr1 N present as meandering up and down transport path It is carried out from the other end side (+ X side in FIG. 2) of the drying apparatus main body Db1 which is downstream. At this time, the atmosphere in the drying chamber Dr1 may be an inert gas such as nitrogen or normal air.

Here, the n driving roll FRn is a roll that rotates in drive itself, for example, to convey the web F _C by rotating by a driving source such as a motor. The m-th non-driving roll Rm is a roll that is not driven by itself and is freely rotatable according to an external force.

The m-th non-driven rolls Rm, for example, rotatably provided with respect to the drying apparatus body Db1, supported by the contact web F _C, while rotating by the friction with the web F _C traveling, conveying the web F _C To do. The n-th driving roll FRn and the m-th non-driving roll Rm are mainly composed of a metal or an alloy, for example.

N-th driving roll FRn is from upstream to downstream of the transport path of the web F _C, are arranged in the order of numbers fitted to n. Further, the m non-driven rolls Rm is from upstream to downstream of the transport path of the web F _C, they are arranged in the order of numbers to be fitted to m.

In the drying chamber Dr1 illustrated in Figure 2, the most upstream side of the conveying path of the web F _C, the first non-driven roll R1 is disposed on the most downstream side of the transport path of the web F _C, 46 non-drive roll R46 is arranged. Further, between the first drive roller FR1 second driving roll FR2, the 2-12 undriven roll R2~R12 are arranged in this order along the conveying path of the web _{F C.} Between the second drive roller FR2 third driving roll FR3, the 13 to 23 non-driven roll R13~R23 are arranged in this order along the conveying path of the web _{F C.} Between the third driving roll FR3 and fourth driving roll FR4, the 24 to 34 non-driven roll R24~R34 are arranged in this order along the conveying path of the web _{F C.} Between the fourth driving roll FR4 and fifth drive roller FR5, a 35 to 45 non-driven roll R35~R45 are arranged in this order along the conveying path of the web _{F C.}

<(2-2-2) Drive roll configuration>
FIG. 3 is a schematic diagram illustrating an example of the n-th driving roll FRn. In Figure 3, as an example of the n-th driving roll FRn, suction roll for transporting the web F _C by rotating while sucking the web F _C is shown. In Figure 3, a transparent web F _C is shown a state being conveyed by the n-th driving roll FRn. The n-th driving roll FRn has almost the same configuration, and therefore, here, the first driving roll FR1 will be described as an example.

The first drive roll FR1, together with a rotary shaft P _FR parallel to the transverse direction of the web F _C (i.e. the width direction), the cross section perpendicular (in Fig. 3 XZ cross-section) is substantially circular in this rotation axis P _FR And rotate around the rotation axis _PFR . The first drive roll FR1 is on the curved surface web F _C contacts (cylindrical surface), the first suction portion on the end side of the one-way parallel to the rotation axis P _FR (FIG. 3 + Y side) has a SA _L, a second suction unit SA _R on the end side in the opposite direction (in FIG. 3 -Y side) to the one direction parallel to the rotation axis _{P FR.} In other words, the first driving roll FR1, the rotary shaft first suction portion SA _L is provided along one end side P _FR, opposite the other end side to the one end side along the rotation axis P _FR first suction unit SA _R is provided.

The first and second suction portions SA _L, SA _R is the number of holes provided in the surface (also referred to as the suction holes), by sucking the web F _C, part (holding section both for holding the web F _C Play a role. The first and second suction portions _SA L, SA _R is while sucking the web _{F C,} since the first drive roll FR1 is rotated about the axis of rotation _{P FR,} web _{F C} is reliably conveyed. In Figure 3, the direction of the web F _C is transported is shown by black arrows.

Further, according to the first driving roll FR1, first and second suction portions _SA L, since the web _{F C} is held by suction by the SA _R, longitudinal web _{F C} in the previous step of the first driving roller FR1 a tension is applied to the direction, the tension being applied in the longitudinal direction of the web F _C may become as discontinuous in the subsequent step of the first drive roll FR1. That is, tension is applied to the longitudinal direction of the web F _C is arbitrarily changed.

The first suction unit SA _L, provided in an annular shape around the rotation axis _{P FR,} has a width _{W SL} in a direction parallel to the rotation axis _{P FR.} Further, the second suction unit SA _R, provided in an annular shape around the rotation axis _{P FR,} has a width _{W SR} in a direction parallel to the rotation axis _{P FR.} Width _{W SL, W SR} may be independently identical or different, but for the web _{F C} is conveyed stably, it be the same width _{W SL, W SR,} the first and second 2 suction unit _SA L, who web _{F C} is uniformly sucked evenly preferably by SA _R. In order to secure the suction force, the widths W _SL and W _SR are preferably set within a range of 20 to 100 mm, for example.

Note that the shapes of the first and second suction portions SA _L, the suction holes provided in the SA _R, is not particularly limited, from the viewpoint of the occurrence of scratches in the web F _C is suppressed, it is applied various shapes Also good. For example, the suction hole may have a slit shape extending in a direction parallel to the rotation axis _PFR , or may have a chamfered shape.

Further, (also referred to as _distance) distance to the first suction portion SA _L and the second suction portion SA _R are spaced away _{W1 FR1} is, the width in the short direction of the web _{F C} in contact with the first drive roll FR1 W2 It is set to be narrower than _FR1 . Here, speaking from a different point of view, the separation distance _{W1 FR1} includes an outer edge portion of the other end of the first suction unit SA _L (FIG. 3 -Y side), one end (Fig second suction unit SA _R 3 corresponds to the distance from the outer edge on the + Y side). The distance of the outer edge of one end of the first suction unit SA _L outer edge and the other end side of the second suction unit SA _R of (in FIG. 3 + Y side) (in FIG. 3 -Y side) is separated Is set to be narrower than the width W2 _FR1 . Then, the center line of the outer edge portion of the outer edge and one end of the second suction unit SA _R of the other end of the first suction unit SA _L (FIG. 3 -Y side) (in FIG. 3 + Y side), the 1 one end of the suction unit SA _L and the center line of the outer edge portion of the outer edge portion and the other end side of the second suction unit SA _R of (in FIG. 3 + Y side) (in FIG. 3 -Y side), the first drive roll and the center line of the lateral direction of the web F _C in contact with the FR1 is preferably matches.

Thus, the first and second suction portions SA _L, in SA _R, a region which is not sucked region for sucking the web F _C is set to not mix. As a result, it is possible to suppress the occurrence of problems in the suction force and the suction mechanism. The route of the web _{F C} is conveyed, so that trouble even deviated in the width direction of the web _{F C} hardly occurs, and the distance _{W1 FR1} and width _{W2 FR1, 0.97 ≧ W1 FR1 /} W2 FR1 It is preferable to satisfy the relationship. By this relationship is satisfied, fast transport of the web F _C is stably possible.

Further, at both ends in the width direction of the web F _C, enough to be wider if wider outer portion than the portion that is sucked first and second suction portions SA _L, the SA _R, the web F _C is When conveyed, wrinkles are likely to be generated and folded at both ends. For this reason, it is preferable that the relationship of W1 _FR1 / W2 _FR1 ≧ 0.90 is satisfied. By this relationship is satisfied, it is possible to speed the transport of the web F _C, improvement in the productivity of the film F _OP is achieved.

Also, of the curved (cylindrical surface) of the web _{F C} contacts the first driving roll FR1, central FR1 _c between the first suction unit SA _L and the second suction unit SA _R is a mirror surface There, for example, a value indicating the roughness of the central portion FR1 _c, may be equal to or less than a predetermined threshold. When the ten-point average roughness (Rz) defined in B0601 (2001 revision) of the Japanese Industrial Standard (JIS) is used as a value indicating the roughness of the central portion FR1 _c , the predetermined threshold is, for example, It may be 0.8 μm. Thus, by contact with a central portion FR1 _c and the web F _C, scratches and deformation hardly occurs on the surface of the web F _C. As a result, the optical characteristics of the film _FOP are improved.

That is, in the n-th driving roll FRn, central FRn _c is a curved surface (cylindrical surface) between the first suction unit SA _L and the second suction portion SA _R is preferably a mirror surface.

<(2-2-3) Relationship among a plurality of driving rolls>
As described above, so as to allow high-speed in the transport of the web _{F C,} the first driving roll FR1, it is preferable that satisfy the relationship of _{0.97 ≧ W1 FR1 / W2 FR1 ≧} 0.90. For the same purpose, it is preferable that the same relationship is satisfied in any of the n-th driving rolls FRn.

Here, in the n-th driving roll FRn, distance the first suction portion SA _L and the second suction portion SA _R is spaced (distance) _is shown as _{W1 FRn,} the n driving roll FRn contacts width of the web _{F C is} a functional group represented as _{W2 FRn.} In this case, so it is possible to speed up the transport of the web _{F C,} is preferably satisfied relationship _{0.97 ≧ W1 FRn / W2 FRn ≧} 0.90. In other words, when the separation distance W1 _FRn is collectively referred to as the separation distance W1, and the width W2 _FRn is collectively referred to as the width W2, it is preferable that the relationship of 0.97 ≧ W1 / W2 ≧ 0.90 is satisfied.

Incidentally, in the first drying zone 110, degree of web F _C is dried when it is dry, the amount of residual solvent is reduced, indicating a gradual narrowing trend width of the web F _C. In other words, in the first drying zone 110, the web F _C is, the more from the upstream conveying path you go downstream, indicating a gradual narrowing trend width of the web F _C. For example, in the first drying zone 110, the width of the web _{F C} narrows about 5 to 10%.

Specifically, than the width _{W2 FR1} of the web _{F C} of the first drive roll FR1 contacts, towards the width _{W2 FR2} of the web _{F C} is narrower that the second drive roll FR2 contacts. Moreover, than the width _{W2 FR2,} towards the width _{W2 FR3} of the web _{F C} is narrower third driving roll FR3 contacts. Additionally, than the width _{W2 FR3,} towards the width _{W2 FR4} of the web _{F C} is narrower fourth driving roll FR4 contacts. Then, than the width _{W2 FR4,} towards the width _{W2 FR5} of the web _{F C} is narrow fifth driving roll FR5 contacts.

Therefore, in order relation of 0.97 ≧ W1 / W2 ≧ 0.90 is maintained in the order of the drive roll web _{F C} contacts, i.e. with increasing n, gradually or stepwise is separation W1 It is preferable to shorten it. For example, it is preferable that the relationship of W1 _FR1 > W1 _FR2 > W1 _FR3 > W1 _FR4 > W1 _FR5 is satisfied. Note that the width _{W SR} width _{W SL} and the second suction portion SA _R of the first suction unit SA _L, to the upstream of the transport path of the web _{F C} may become gradually or stepwise shorter toward the downstream, It may be constant.

According to such a configuration, the width of the web F _C, the relative position of n-th driving roll FRn held by suction is substantially constant. Accordingly, stable tension is applied in the width direction of the web F _C in the first drying step, the optical properties of the film are further improved.

<(2-2-4) One Modification of Driving Roll>
FIG. 4 is a schematic diagram showing a modification of the nth drive roll FRn. In Figure 4, as a modification of the n-th driving roll FRn, and a drive roll for conveying the web F _C by rotating while nipping the web F _C between the n-th press roll PRn is shown. Here, an example in which a natural number equal to or less than N is applied to n and N is 5 will be described. In Figure 4, similar to FIG. 3, a transparent web F _C is shown a state being conveyed by the n-th driving roll FRn. The n-th driving roll FRn has almost the same configuration, and therefore, here, the first driving roll FR1 will be described as an example.

The first drive roll FR1, together with a rotary shaft P _FR parallel to the transverse direction of the web F _C (i.e. the width direction), the cross section perpendicular (in FIG. 4 XZ cross-section) is substantially circular in this rotation axis P _FR And rotate around the rotation axis _PFR . The first press roll PR1, along with parallel rotation axes _{P PR} in the width direction of the web _{F C,} a cross-section perpendicular to the rotation axis _{P PR} (in Fig. 4 XZ cross-section) has a substantially circular, rotating It rotates about the axis _PPR . In addition, it is preferable that 1st press roll PR1 rotates by driving itself.

First press roll PR1 includes a first pressing portion PR _L parallel direction end portion side to the rotation axis _{P PR} (in Fig. 4 + Y side), opposite to the one direction parallel to the rotation axis _{P PR} a second pressing portion PR _R in the direction of the end side (in FIG. 4 -Y side). Then, the first pressing portion PR _L, first rotation axis P parallel direction end side _FR of the curved web F _C contacts the driving roller FR1 (cylindrical surface) (in FIG. 4 + Y by the portion of the side), the web F _C is held. Further, the second pressing portion PR _R, the rotation axis direction opposite to the end side to the one direction parallel to the P _FR of the curved web F _C contacts the first driving roll FR1 (cylindrical surface) ( by the portion of Figure 4 in the -Y side), the web _{F C} is held.

That is, the first press roll PR1 is part which holds the web _{F C} by sandwiching the web _{F C} between the first pressing portion PR _L (also referred to as a first holding portion) and the HP _L, the second pressing portion PR to sandwich the web _{F C} between _R (also referred to as a second holding portion) portion for holding the web _{F C} in and an HP _R. The first press roll PR1, the first and second clamping portions _HP L, while nipping the web _{F C} in HP _R, since the first drive roll FR1 is rotated about the axis of rotation _{P FR,} web F _C is transported securely. In Figure 4, the direction of the web F _C is transported is shown by black arrows.

In the first press roll PR1, width in a direction parallel to the rotation axis _{P FR} of the first holding portion HP _L is equivalent to the width _{W SL,} a direction parallel to the rotation axis _{P FR} of the second holding portion HP _R The width at corresponds to the width _WSR . Further, the outer edge of the other end of the first holding portion HP _L (FIG. 4 in the -Y side), and the outer edge portion of one end side of the second holding portions HP _R (in FIG. 4 + Y side) is separated The distance (separation distance), that is, the separation distance between the first clamping part HP _L and the second clamping part HP _R corresponds to the separation distance W1 _FR1 . The distance of the outer edge portion of one end side of the first holding portion HP _L outer edge and the other end side of the second holding portion HP _R of (in FIG. 4 + Y side) (in FIG. 4 -Y side) is separated Is set to be narrower than the width W2 _FR1 .

In this configuration, the intermediate point between the outer edge of the other end of the first holding portion HP _L outer and one end side of the second holding portion HP _R of (in FIG. 4 -Y side) (Fig. 4, the + Y side) When an intermediate point between the outer edge of the outer edge portion and the other end side of the second holding portion HP _R at one end of the first holding portion HP _L (in FIG. 4 + Y side) (Fig. 4 in the -Y side), the the lateral direction of the center line of the web F _C that contacts the first drive roll FR1 is preferably matches. Then, so as to allow high-speed conveyance of the web _{F C,} distance _{W1 FR1} is set to be narrower than the width _{W2 FR1} in the lateral direction of the web _{F C} in contact with the first drive roll FR1 It is preferable that 0.97 ≧ W1 _FR1 / W2 _FR1 is satisfied. Further, from the viewpoint of improving the productivity of high-speed conveyance by the film _{F OP} of the web _{F C} can be _achieved, the relationship of W1 _{FR1 / W2} FR1 ≧ 0.90 is it is preferred that satisfied.

Furthermore, among the curved (cylindrical surface) of the web _{F C} contacts the first driving roll FR1, the central portion FR1 _c between the first clamping portion HP _L and the second clamping portion HP _R, a mirror-like There, for example, a value indicating the roughness of the central portion FR1 _c is a predetermined threshold value (e.g., Rz = 0.8 [mu] m) may be any less. Thus, by contact with a central portion FR1 _c and the web F _C, scratches and deformation hardly occurs on the surface of the web F _C. As a result, the optical characteristics of the film _FOP are improved.

That is, in the n-th driving roll FRn, central FRn _c is a curved surface (cylindrical surface) between the first holding portion HP _L and the second clamping portion HP _R is preferably a mirror surface.

In the n-th driving roll FRn, the distance (separation distance) between the first clamping part HP _L and the second clamping part HP _R corresponds to the separation distance W1 _FRn , and the n-th driving roll FRn is in contact with the n-th driving roll FRn. the width of the web _{F C} that _corresponds to a _{W2 FRn.} In this case, so as to enable high-speed transport of the web _{F C,} is preferably satisfied relationship _{0.97 ≧ W1 FRn / W2 FRn ≧} 0.90. In other words, when the separation distance W1 _FRn is collectively referred to as the separation distance W1, and the width W2 _FRn is collectively referred to as the width W2, it is preferable that the relationship of 0.97 ≧ W1 / W2 ≧ 0.90 is satisfied.

Further, in the first drying zone 110, in response to a decrease of the width of the web _{F C} due to drying of the web _{F C,} for the relationship 0.97 ≧ W1 / W2 ≧ 0.90 is maintained, the web _{F C} is It is preferable that the separation distance W1 gradually or stepwise decreases in the order of the driving rolls in contact, that is, with an increase in n. According to this structure, the n-th driving roll FRn, the ends of the web F _C is maintained substantially the same manner. Therefore, is suppressed variation in tension in the width direction of the web F _C, uniform retardation (Retardation) is realized by the width direction in the film F _OP after winding. Furthermore, the web F _C is, since the variation in the degree of shrinkage is suppressed in the width direction during the drying, a high retardation in the film F _OP after winding is realized.

Then, according to the above-described n-th driving roll FRn, for example, for those width of the film F _OP after winding is wide such 1800~4000mm like also, the improvement of improvement and productivity of the optical properties Figure Can be.

Incidentally, when the relationship of 0.97 ≧ W1 / W2 ≧ 0.90, which is described above is realized, the first in the drying zone 110 can hardly meanders web F _C is the width direction contrivance is performed Is desirable. For example, uniformity of the degree of drying in the width direction of the web F _C, that such improvement of the dimensional accuracy and mounting accuracy of the n-th driving roll FRn and the m non-driven roll Rm is achieved desirable.

Meanwhile, the film manufacturing apparatus, generally, if reduced number of drive rolls being used, in order to transport the stable web F _C is achieved, a larger tension to the web F _C along the transport direction It tends to be hung. In this case, longitudinally extending web F _C is along the conveying direction, it is easy reduction in retardation R ₀ is generated. At this time, as reduction in retardation R ₀ is suppressed, countermeasure is also considered to be the web F _C Gayori greater stretching with a tenter 112, since the haze is increased, undesirably. Therefore, the reduction of the tension applied in the longitudinal direction of the web F _C, from the viewpoint of improvement in optical characteristics can be achieved, it the number of driving rolls used are often preferred.

<(2-2-5) Non-driving roll>
FIG. 5 is a schematic diagram illustrating an example of the m-th non-driving roll Rm. In Figure 5, a transparent web F _C is a state which is conveyed while in contact with the m non-driven rolls Rm is shown. Note that the m-th non-driving roll Rm has substantially the same configuration as each other, and therefore, here, the first non-driving roll R1 will be described as an example.

The first non-driven rolls R1, together with a rotary shaft P _R parallel to the transverse direction of the web F _C (width direction), the cross section perpendicular (in Fig. 5 XZ cross-section) is substantially circular in this rotation axis P _R a, it rotates around the rotation axis P _R. The rotation of the first non-driven roll R1, the web F _C is conveyed. In Figure 5, the direction of the web F _C is transported is shown by black arrows.

The first non-drive roll R1 is in the curved (cylindrical surface) of the web F _C contacts, first non on the end side of the one-way parallel to the rotation axis P _R (in FIG. 5 + Y side) has a mirror surface portion IA _L, the direction parallel to the rotation axis P _R having a second non-mirror surface portion IA _R on the end side in the opposite direction (in FIG. 5 -Y side). In other words, the first non-driven roll R1, the rotation shaft first non-specular portion IA _L is provided on one end side along the P _R, reverse of the other end side to the one end side along the rotation axis P _R the second non-specular portion IA _R is provided.

The first and second non-mirror surface portions IA _L and IA _R have a surface that is not smooth due to, for example, a concave portion and / or a convex portion, and have, for example, a plurality of groove portions along the circumferential direction of the first non-driving roll R1. . The first and second non-specular unit IA _L, IA _R is provided in an annular shape around the rotation axis P _R, it has a constant width in a direction parallel to the rotation axis P _R. These first and second non-specular unit _IA L, IA _R acts as a shape for assisting the transport of the web _{F C} (also referred to as transport assisting shape). The first and second non-specular unit _IA L, IA _R is in contact with the vicinity of both end portions widthwise of the webs _{F C.} In FIG. 5, the first and second non-specular unit IA _L, IA _R is, the state in contact with both end portions and near both ends in the width direction of the web F _C is shown.

Also, the first non-driven roll R1, among the curved (cylindrical surface) in contact with the web F _C, a portion between the first non-mirror surface portion IA _L and the second non-specular unit IA _R, mirror-like It has become.

In the first non-drive roll R1 having the above structure, first and second non-specular unit _IA L, the presence of IA _R, when the web _{F C} is conveyed, the web _{F C} in the first non-driven rolls R1 Air becomes difficult to get caught in between. Thus, when the web F _C is conveyed, between the first non-drive roll R1 and the web F _C, hardly occurs variation in the friction coefficient, the web F _C hardly slip. Therefore, the transport speed of the web F _C becomes stable possible at high speed, meandering in the width direction of the web F _C is suppressed, occurrence of abrasion of wrinkles and surface of the web F _C is suppressed. Moreover, the central portion of the web _{F C} is not damaged by the first non-mirror surface portion of the first non-driven rolls R1 IA _L and the second non-specular unit IA _R. Therefore, the optical characteristics of the film _FOP are improved.

<(2-2-6) Relationship among a plurality of non-driven rolls>
In the first drying zone 110, the width _{W2 Rm} of the web _{F C} that contact with the m non-driven rolls Rm as drying of the web _{F C} progresses decreases. Here, the order of the width _W2 R1 _{~W2 R46,} i.e. with increasing m, width _{W2 Rm} of the web _{F C} becomes narrow.

Therefore, the order of the non-drive roll web F _C contacts, i.e. with increasing m, shorter first non-specular portion IA _L and distance W3 between the second non-specular portion IA _R is gradually or stepwise It is preferable. Specifically, the separation distance W3 _Rm between the first non-mirror surface portion IA _L and the second non-mirror surface portion IA _R in the m-th non-driving roll Rm is in the order of the separation distance W3 _R1 to the separation distance W3 _R46 , that is, m It is preferable to narrow gradually or stepwise with increasing. Thus, the support of the web F _C by the m non-driven roll Rm becomes more uniform. As a result, the maintenance of a more stable and the optical properties of the film F _OP by the m non-driven roll Rm transport of the web F _C is achieved.

In addition, the following aspect can be considered as an example in which the separation distance W3 _Rm is gradually reduced. The separation distances W3 _{R2 to} W3 _{R12 in the second} to twelfth non-driving rolls _{R2 to R12} disposed between the first driving roll FR1 and the second driving roll FR2 are constant. The separation distances W3 _{R13 to} W3 _R23 in the thirteenth to twenty-third non-driving rolls _{R13 to R23} arranged between the second driving roll FR2 and the third driving roll FR3 are constant. The separation distances W3 _{R24 to} W3 _{R34 in the} 24th to 34th non-driving rolls _{R24 to R34} disposed between the third driving roll FR3 and the fourth driving roll FR4 are constant. The separation distances W3 _{R35 to} W3 _{R45 in the} 35th to 45th non-drive rolls _{R35 to R45} arranged between the fourth drive roll FR4 and the fifth drive roll FR5 are constant. The separation distances W3 _{R13 to} W3 _R23 are narrower than the separation distances W3 _{R2 to} W3 _R12 , the separation distances W3 _{R24 to} W3 _R34 are narrower than the separation distances W3 _{R13 to} W3 _R23 , and the separation distances W3 _{R24 to} W3 _R34 are smaller than the separation distances W3 _{R24 to} W3 _R34. The distances W3 _{R35 to} W3 _R45 are narrow.

<(3) Second Embodiment of Film Manufacturing Apparatus>
<(3-1) Outline of Film Manufacturing Apparatus>
FIG. 6 is a schematic diagram of a film manufacturing apparatus 200 according to the second embodiment. In the film manufacturing apparatus 200, the film is manufactured using the solution casting film forming method.

  As shown in FIG. 6, the film manufacturing apparatus 200 includes a drum 202, a peeling roll 204, a first drying zone 206, a tenter 208, a second drying zone 210, a winder 212, a casting die 214, and a dope supply mechanism. 216.

  The casting die 214 is close to and faces the outer surface (also referred to as drum outer surface) 224 of the drum 202. The drum 202 is an example of a metal support 500 and the drum outer surface 224 is an example of a support surface 502. The drum outer surface 224 as the support surface 502 has a mirror shape.

In the film manufacturing apparatus 200, when the film _FOP is manufactured, the drum 202 rotates and the drum outer surface 224 travels in the vicinity of the casting die 214. At this time, the doped doped supply mechanism 216 to the casting die 214 is supplied, casting film F _C from doped dope is cast drum outer surface 224 with respect to the drum outer surface 224 of the casting die 214 It is formed.

Here, of the drum outer surface 224 of the support surface 502, the first section _{R AB} of up to the stripping position _{P B} along the casting position _{P A} in the running direction of the drum outer surface 224, cast film _{F C} Is formed. Incidentally, the casting position _{P A,} of the drum outer surface 224, a position where the dope is cast by the casting die 214, the peeling position _{P B} is the casting film _{F C} is peeled off from the drum outer surface 224 located It is. Temperature in the first section R _AB of the drum outer surface 224 is adjusted by a temperature adjusting device or the like including a heater or the like.

Casting film _{F C} is dried and solidified on the drum outer surface 224, it is peeled from the drum outer surface 224 web _{F C} is formed. The peeled web F _C is further dried and in the first drying zone 206, and stretching in the tenter 208, and further drying in the second drying zone 210 is sequentially subjected winder 212 It is wound up by. Thus, a roll of the film _{F OP} is produced. The contents of the processing for a web F _C peeled from the drum outer surface 224 is modified as necessary.

<(3-2) Measures for improving optical properties of film in first drying>
The first drying zone 206 has the same configuration (FIG. 2) as the first drying zone 110 according to the first embodiment. Thus, the improvement of the optical characteristics in the winding of the film after F _OP, and improve the productivity of the film F _OP is achieved.

<(4) Material of metal support>
The material of the metal support 500 may be a metal or an alloy. When the material of the metal support 500 is an alloy, the alloy is preferably stainless steel such as SUS304 or SUS316. Further, a mode in which a plating process such as hard chrome plating or amorphous chrome plating is performed on the drum outer surface 224 is also conceivable.

<(5) Casting die>
Casting die 118,214, it is not particularly limited, from the viewpoint that the thickness of the rolled film F _C metal support 500 Ueno flow becomes uniform, a coat hanger die, pressure die, etc. T-die Is desirable. Blade, the thickness of the casting film F _C at a reverse roll coater or the like may be adjusted.

<(6) Dope>
The dope is a viscous fluid in which a thermoplastic resin and necessary additives are dissolved or dispersed in a solvent. In the film manufacturing apparatus 100, the dope is sent from the dope tank 150 to the casting die 118 by the liquid feeding pump 152, and in the film manufacturing apparatus 200, the dope is sent from the dope tank 250 to the casting die 214 by the liquid feeding pump 252.

  The thermoplastic resin is not particularly limited, but is desirably a cellulose ester such as cellulose triacetate or cellulose acetate propionate.

  The solvent is not particularly limited, but is preferably a mixture of a good solvent and a poor solvent. When the thermoplastic resin is a cellulose ester, for example, methylene chloride or the like may be employed as a good solvent, and methanol, ethanol, or the like may be employed as a poor solvent.

The additive may be, for example, a plasticizer, an ultraviolet absorber, fine particles, and the like. Examples of the plasticizer include phosphate ester type plasticizers. Examples of ultraviolet absorbers include benzotriazole compounds. Examples of the fine particles include a matting agent for imparting slipperiness, and examples thereof include fine particles of a compound containing silicon dioxide. Furthermore, other additives for adjusting the retardation (R _t ) in the thickness direction may be added to the dope.

<(7) Target of application of measures for improving optical properties of film in first drying>
Measures to improve the optical properties of the film F _OP in the first drying zone 110,206 is applied to the production of films, in particular, is suitably applied to the manufacture of optical film improve the uniformity of the physical properties it is expected . For example, it can be suitably applied to the production of polarizing plate protective films, polarizing films, retardation films, antireflection films, alignment films, antireflection films used in plasma display panels, and electromagnetic shielding films used in liquid crystal display panels. It is.

  In addition, a polarizing plate is manufactured by affixing the polarizing plate protective film prepared according to said film manufacturing method on the surface of the polarizer which consists of PVA (polyvinyl alcohol). Thereby, a high quality polarizing plate can be manufactured. Furthermore, a display device such as a liquid crystal display panel in which the polarizing plate is incorporated can be manufactured. Thereby, a high-quality display device can be manufactured.

  It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

<Production conditions for Examples and Comparative Examples>
In the film manufacturing apparatus in which the configuration of the first drying zone 106 is appropriately changed based on the film manufacturing apparatus 100 shown in FIGS. 1 and 2, a cellulose triacetate film (TAC) having a film thickness of 40 μm and a width of 2800 mm is used. (Also called a film) was produced by a solution casting method. That is, here, as an example of the film manufacturing apparatus, a configuration in which there are five n-th driving rolls FRn and 46 m-th non-driving rolls Rm is used as a base. Here, the suction roll was used as a drive roll, and the manufactured TAC film was made into Examples 1-10 and Comparative Examples 1-3.

  Here, as shown in Tables 1 and 2 below, (Condition 1) Surface roughness at the center of the drive roll, (Condition 2) Number of drive rolls used, (Condition 3) Separation distance in the drive roll The ratio (W1 / W2) between W1 and width W2 and (Condition 4) separation distance W3 of the non-driving roll were changed.

Specifically, with respect to the condition 1, in the manufacture of Examples 1 and 2 and Comparative Examples 1 and 2, the surface roughness Rz at the central portion FR1 _c of the first drive roll FR1 is 0.6, 0.8, It was changed to 1.0 and 1.2. In the production of Comparative Example 3, a suction roll and a plurality of suction holes on substantially the entire surface is provided in contact with the web F _C of the first drive roll FR1 (also referred to as entire suction roll) was used. In each preparation of other embodiments 3-10, in the same manner as in Example 2, the surface roughness Rz is 0.8 in the central portion _FR1 c of the driving roll _{(FR2 c ~FR5} c). In each manufacture of Examples 1 to 10 and Comparative Examples 1 and 2, the widths W _SL and W _SR of the first and second suction portions SA _L and SA _R in each drive roll were set to 30 mm.

  Regarding condition 2, in each of the manufacture of Examples 1, 2, 8, 9 and Comparative Examples 1 to 3, the first driving roll FR1 is adopted among the first to fifth driving rolls FR1 to FR5, and the second to fifth driving is performed. A configuration in which rolls FR2 to FR5 were replaced with non-driven rolls was used. In manufacture of Example 3, 1st and 5th drive rolls FR1 and FR2 are employ | adopted among 1st-5th drive rolls FR1-FR5, and the 3rd-5th drive rolls FR3-FR5 are substituted by the non-drive roll. Was used. In manufacture of Example 4, 1st-3rd driving roll FR1-FR3 is employ | adopted among 1st-5th driving roll FR1-FR5, and the 4th, 5th driving roll FR4, FR5 was substituted by the non-driving roll. Was used. In each manufacture of Examples 5 to 7, first to fifth drive rolls FR1 to FR5 were employed. Here, in each manufacture of Examples 2, 3, 4, and 5, the value of W1 / W2 in each drive roll is set to a constant 0.95, and the number of drive rolls used is 1, 2, 3 in order. , Increased to five.

  For condition 3, in each manufacture of Examples 1 to 5, 10 and Comparative Examples 1 and 2, each drive roll satisfied the relationship of W1 / W2 = 0.95. At this time, in each manufacture of Examples 1 to 5 and Comparative Examples 1 and 2, each non-driving roll satisfied a relationship of W3 / W2≈0.96. Further, in the manufacture of Example 8, the first drive roll FR1 was changed to satisfy the relationship of W1 / W2 = 0.90 based on the manufacturing conditions of Example 2. At this time, each non-driving roll satisfied the relationship of W3 / W2≈0.91. Further, in the manufacture of Example 9, the first drive roll FR1 was changed to satisfy the relationship of W1 / W2 = 0.89, based on the manufacturing conditions of Example 2. At this time, each non-driving roll satisfied a relationship of W3 / W2≈0.90.

  Moreover, in each manufacture of Examples 6 and 7, the separation distance W1 in each drive roll was made constant at 1800 mm, and the value of W1 / W2 increased as it became downstream of the transport path. Specifically, in the manufacture of Example 6, the value of W1 / W2 is 0.89 for the first drive roll FR1, 0.897 for the second drive roll FR2, and 0.904 for the third drive roll FR3. Thus, it was 0.911 for the fourth drive roll FR4 and 0.916 for the fifth drive roll FR5. At this time, each non-driving roll satisfied a relationship of W3≈1820 mm. On the other hand, in the manufacture of Example 7, the value of W1 / W2 is 0.95 for the first drive roll FR1, 0.952 for the second drive roll FR2, 0.959 for the third drive roll FR3, It was 0.966 for the 4-drive roll FR4 and 0.972 for the fifth drive roll FR5. At this time, each non-driving roll satisfied a relationship of W3≈1850 mm.

  Regarding condition 4, in the manufacture of Example 5, each non-driven roll satisfied the relationship of W3 / W2≈0.96. On the other hand, in the manufacture of Example 10, the manufacturing condition of Example 5 was used as a base, and the separation distance W3 in each non-driving roll was changed to be constant at 1800 mm. That is, in the manufacture of Example 10, the value of W3 / W2 increased as the value became downstream of the transport path. Specifically, in the manufacture of Example 10, the maximum value of W3 / W2 was 0.98 and the minimum value was 0.93.

Further, the residual solvent content of the web F _C is 15% when in contact with the first drive roll FR1, upon contact with the second drive roll FR2 is 12%, in contact with the third driving roll FR3 10%, 7% when contacting the fourth drive roll FR4, and 5% when contacting the fifth drive roll FR5. Note that the residual solvent rate in time of the web F _C is drying, conveying speed, drying time in the film production apparatus 100 was determined by actual measurement by sampling the conditions according to the temperature. The residual solvent amount can be obtained from the following equation.

Residual solvent amount (% by mass) = {(M _f −N _f ) / N _f } × 100
Here, M _f is the mass when the mass at any time, the N _f which was dried 3 hours at 110 ° C. having a mass M _f of the film.

As described above, when the web F _C is conveyed in the first drying zone 110, together with the drying of the web F _C, the width WB of the web F _C when peeled from the belt outer surface 130 is a reference, The shrinkage rate (also referred to as width shrinkage rate) increases. The width shrinkage of the web _{F C} is becomes 3.0% when in contact with the first drive roll FR1, becomes 3.8% when in contact with the second drive roll FR2, contact the third driving roll FR3 And 4.5% when contacted with the fourth drive roll FR4, and 5.8% when contacted with the fifth drive roll FR5.

Furthermore, in each preparation of Example 1～5,8,10 and Comparative Examples 1 to 3, the speed of the web _{F C} is transported (also referred to as the conveying speed) was set to 100 m / min. Further, in the preparation of Example 6, 7, 9, the web F _C is transported at a high speed, since the problem such as folding and wrinkles are generated in both end portions in the width direction, so that this problem does not occur, the conveying speed However, it was 50 m / min.

<Other manufacturing conditions>
The material of the endless belt 106 is SUS316 stainless steel, and the belt outer surface 130 of the endless belt 106 is a super mirror surface. A coat hanger die was used as the casting die 118.

  The composition of the dope, that is, the content of each component in the dope is shown below.

Cellulose acetate propionate (acetyl group substitution degree + propionyl group substitution degree = 2.45) (Mn = 60000, Mw = 18000, Mw / Mn = 3.00): 100 parts by weight Triphenyl phosphate: 8 parts by weight Ethylphthalic acid Ruethyl glycolate (EPEG): 4 parts by weight Tinuvin 109 (manufactured by Ciba Specialty Chemicals): 0.5 part by weight Tinuvin 171 (manufactured by Ciba Specialty Chemicals): 0.5 part by weight Methylene chloride: 418 weights Methanol: 23 parts by weight Aerosil (AEROSIL R972V manufactured by Nippon Aerosil Co., Ltd.): 0.1 parts by weight.

Here, the temperature of the endless belt 106 was set to 25 ° C., and the traveling speed of the endless belt 106 was set to a desired speed within a range of 50 to 150 m / min. In addition, the drying temperature in the first drying zone 110 was 90 ° C., and the drying temperature in the second drying zone 114 was 125 ° C. Stretching of the web F _C in the tenter 112 was performed under the conditions web F _C is stretched 1.60 times in the width direction in an atmosphere of 180 ° C. When the residual solvent content of about 5 wt%. Further, with respect to near both ends of the web _{F C} emerging from the second drying zone 114, width 10 mm, the knurling height 8μm decorated.

<Measuring method of optical characteristics according to Examples and Comparative Examples>
For the films of Examples 1 to 10 and Comparative Examples 1 to 3 manufactured as described above, in-plane retardation R ₀ , retardation R _{t in the} thickness direction, haze, and width The in-plane retardation R ₀ variation in the direction was measured.

Retardations R ₀ and R _t were obtained by the following method.

  First, after a film of a predetermined size cut out from a wound roll-shaped film is left in an environment of a temperature of 23 ° C. and a humidity of 55% RH for 24 hours, a sample as a measurement target (also called a measurement sample) ) The optical characteristics of the measurement sample were measured in an environment where the temperature was 23 ° C. and the humidity was 55% RH.

Specifically, the film thickness d (unit: nm) of the measurement sample was measured with a contact-type film thickness meter. Here, as a contact-type film thickness meter, an ultra-sensitive film thickness measuring device manufactured by Seiko EM Co. was used. Moreover, the average refractive index in the measurement sample was measured with an Abbe refractometer. Next, when the measured average refractive index and film thickness are input with the measurement sample set in the automatic refractive index measuring machine, each angle (irradiation) with which the measurement sample is irradiated with light The refractive index is measured for (angle), and the refractive index _nx , refractive index _ny , and refractive index _nz in the measurement sample are calculated. Then, the following equation (1), according to (2), the retardation _R 0, _{R t} was determined.

_{R 0 = (n x -n y} ) × d ··· (1)
R _t = {(n _× 10 n _y ) / 2−n _z } × d (2).

Here, the refractive index _nx is the refractive index in the direction of the slow axis in the film plane, and the refractive index _ny is the refractive index in the direction of the fast axis perpendicular to the slow axis in the film plane. The refractive index _nz is the refractive index in the direction perpendicular to the film surface. Further, KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd. was used as an automatic refractive index measuring device, and retardations R ₀ and R _t for light having a wavelength of 590 nm were determined.

In the measurement of the retardation R _0, R _t, are arranged in the substantially straight line in the width direction in the measurement sample containing the full width of the film F _OP, spaced apart and central position in the width direction, from the position of the center by 100mm position And the measurement position. Then, for all the measurement positions, the retardation R ₀ in the manner described _above, R _t is measured, the average value was the retardation R _0, R _t as a measurement result in the measurement sample.

At this time, for each measurement sample, the retardation R ₀ is determined for each measurement position in the width direction, is the average value R _0M is the reference, the variation V _{R0 (in%)} of the retardation R ₀ is I was asked. Here, the maximum value of the retardation _{R 0} is the _{R 0max} in the width direction, the minimum value of the retardation _{R 0} is an _{R 0min} in the width direction, the variation _{V R0} is the relation of the following formula (3) Have.

_{V R0 = {(R 0max -R} 0min) / R 0M} × 100 ··· (3).

  The haze of the measurement sample was measured using a 1001DP type haze meter manufactured by Nippon Denshoku Industries Co., Ltd. This haze measurement was performed according to the method defined in JIS K6714.

<Measurement of Conveyable Speed According to Examples and Comparative Examples>
In each manufacturing apparatus according to Examples 1 to 10 and Comparative Examples 1 to 3, the transport speed of the web _{F C} is in the range of 50 to 150 m / min, conveying speed by 50 m / min to 25 m / min is increased, the web whether folding or wrinkles was confirmed at both ends in the width direction of the F _C. Then, the maximum value of the transport speed folding or wrinkle is not generated at both ends in the width direction of the web F _C were determined.

<Measurement results>
The measurement results obtained for Examples 1 to 10 and Comparative Examples 1 to 3 are shown in Table 3 below.

As shown in Table 3, in each of Examples 1 to 10 and Comparative Examples 1 to 3, the in-plane retardation R ₀ was 45 or more and the thickness direction retardation R _t was 120 or more. It was.

As shown in the measurement results of Examples 1 and 2 and Comparative Examples 1 and 2, the haze tends to decrease as the surface roughness Rz at the central portion FR1 _c of the first drive roll FR1 decreases. It was. Then, the surface roughness Rz at the center FR1 _c is less 0.8μm which corresponds to the mirror state haze was greatly reduced. Thus, by the central portion FR1 _c is a mirror surface, it was found that the optical properties are greatly improved. Further, as shown by the measurement results of Comparative Example 3, it was found that if the first drive roll FR1 is a full-surface suction roll, the haze increases rapidly and the optical characteristics are significantly reduced. This phenomenon, a plurality of suction holes provided on the entire surface suction roll, is inferred to be due to that caused scratches and / or variations on the surface of the web F _C.

As shown in the measurement results of Examples 2, 3, 4, and 5, as the number of driving rolls used in the first drying zone 110 increases, the retardations R ₀ and R _t increase. Haze was reduced, and variation in retardation _R0 in the width direction was also reduced. Thereby, it turned out that an optical characteristic improves with the increase in the number of the drive rolls used in the 1st drying zone 110. FIG. Such improvement in optical properties, with an increase in the number of driving rolls used in the first drying zone 110, is inferred to be due to tension applied in the width direction of the web F _C is more uniform It was. Further, by the number of driving rolls used increases, also by tension applied in the longitudinal direction of the web F _C is reduced, which is assumed that the optical properties are improved.

As shown by the measurement results of Examples 2, 8, and 9, as the value of W1 / W2 in the first drive roll FR1 increased, the variation in retardation _R0 in the width direction decreased. Such improvement in the optical properties, by partial closer to the end of the web F _C is held by the first drive roll FR1, the affected parts of the holding by the first drive roll FR1 in the web F _C reduction while it is, was inferred to be due to uniform tension is multiplied by the width direction with respect to the wider portion of the web F _C.

Further, when the value of W1 / W2 is less than 0.90, the transportable speed is 50 m / min or less, whereas when the value of W1 / W2 is 0.90 or more, the transportable speed is 150 m / min. It became the following. This is because the portion closer to the end of the web F _C is held by the first drive roll FR1, presumed to be due to Orekomi and / or wrinkles in the end portions of the web F _C is suppressed It was done.

As shown in the measurement results of Examples 5 to 7, both the haze and the variation in retardation R ₀ in the width direction were suppressed in Example 5 than in Examples 6 and 7. Here, in each manufacture of Examples 6 and 7, the separation distance W1 was constant in common with the first to fifth drive rolls FR1 to FR5, whereas in the manufacture of Example 5, 0.97 ≧ W1 / W2. In order to maintain the relationship of ≧ 0.90, the value of W1 / W2 is set to a constant value of 0.95 in common with the first to fifth drive rolls FR1 to FR5. This will suppress variation in the tension applied to the width direction of the web F _C, uniform retardation R ₀ is inferred to have been achieved by the width direction.

Further, in the manufacturing conditions of Examples 6 and 7, the transportable speed was 50 m / min or less, whereas in the manufacturing conditions of Example 5, the transportable speed was 150 m / min or less. Under the manufacturing conditions of Example 6, the W1 / W2 value in the first and second drive rolls FR1 and FR2 was less than 0.9, so it was assumed that the transportable speed was reduced. Furthermore, in the manufacturing conditions of Example 7, the value of W1 / W2 in the fifth driving roll FR5 exceeds 0.97, further, the variation of the tension applied in the width direction of the web _{F C,} in the transport of the web _{F C} It was presumed that meandering in the width direction was likely to occur and the transportable speed was reduced.

As shown by the measurement results of Examples 5 and 10, both the haze and the variation in retardation R ₀ in the width direction were lower in Example 5 than in Example 10. Such improvement in optical characteristics, in accordance with the contraction of the width of the web _{F C,} W3 in 1-32 undriven roll R1~R46 stepwise narrowed, in the 1-46 undriven rolls R1~R46 the value of W3 / W2 is more uniform, was speculated to be due to the support aspects of the web F _C is more uniform by 1-32 undriven rolls R1～R46. Further, the transportable speed of Example 5 was higher than that of Example 10. Such result was assumed that the transport of the web F _C by 1-32 undriven roll R1~R46 is due to more uniform and stable it.

DESCRIPTION OF SYMBOLS 100,200 Film manufacturing apparatus 106 Endless belt 110,206 1st drying zone 112,208 Tenter 114,210 2nd drying zone 130 Belt outer surface 202 Drum 224 Drum outer surface 500 Metal support body (support body)
502 support surface F _C casting film web FR1~FR5 first to fifth drive roller FR1 _c ~FR5 _c central FRn n-th driving roll HP _L first holding portion HP _R second sandwiching portion IA _L first non-specular part IA _R second non-specular portion PR1~PR5 first to fifth press roll PR _L first pressing portion PR _R second pressing part _{P FR,} P R, P _PR rotary shaft R1~R46 1-32 non-driven rolls Rm _M- th non-driving roll SA _L first suction part SA _R second suction part

Claims (8)

(a) A step of forming a casting film by casting a thermoplastic resin solution, which is a raw material of a film in a solution casting film forming method, on the surface of a support composed of a metal or an alloy. When,
(b) solidifying the cast film formed in the step (a) on the surface;
(c) peeling the cast film solidified in the step (b) from the surface to form a web;
(d) drying the web formed in step (c);
(e) stretching the web dried in the step (d);
(f) drying the web stretched in the step (e);
With
In the step (d), in a state where the content of the solvent in the web is 5% by weight or more, a portion including the vicinity of both ends of the web except for at least a central portion of the web in a short direction. Conveying the web in the longitudinal direction of the web perpendicular to the short direction, while sucking and / or pinching;
The manufacturing method of the film in which the said drive roll has the surface of the mirror surface state which contacts the said center part. A first rotating shaft that is parallel to the short direction of the web; and a first holding portion that sucks and / or clamps the web provided on one end side along the first rotating shaft. A second holding portion that sucks and / or clamps the web provided on the other end side opposite to the one end side along the first rotation axis,
In the drive roll, when the first separation distance between the first holding part and the second holding part is W1, and the width of the web in the short direction is W2, 0.97 ≧ W1 / The manufacturing method of the film of Claim 1 which satisfy | fills the relationship of W2> = 0.90.   The manufacturing method of the film of Claim 1 or Claim 2 in which the said drive roll contains a suction roll.   The method for producing a film according to any one of claims 1 to 3, wherein the drive roll includes a drive roll that sandwiches the web with a pressing roll.   The method for producing a film according to any one of claims 1 to 4, wherein the web is conveyed by the two or more drive rolls in the step (d).   The method for producing a film according to claim 5, wherein the first separation distance of the drive roll is gradually or stepwise reduced in the order in which the web contacts in the step (d). In the step (d), the web is conveyed while sequentially contacting a plurality of non-driven rolls that are not driven,
Each non-driving roll has a second rotation axis parallel to the short direction of the web, and first and second non-mirror surface portions that are in contact with the vicinity of both ends of the web in the short direction. And
The first non-mirror surface portion is provided on the first end side along the second rotation axis of each non-driving roll,
The second non-mirror surface portion is provided on the second end side opposite to the first end side along the second rotation axis of each non-driving roll,
A second separation distance between an outer edge of the first non-mirror surface portion on the first end portion side and an outer edge of the second non-mirror surface portion on the second end portion side is determined so that the web contacts in the step (d). The method for producing a film according to any one of claims 1 to 6, wherein the film becomes shorter gradually or stepwise in the order of the non-driving rolls. A support that is formed using a metal or an alloy and that forms a casting film by casting a thermoplastic resin solution that is a raw material of a film in a solution casting film formation method on the surface;
A first drying region for drying a web formed by solidifying and peeling the cast film on the surface;
A stretching section for stretching the web dried by the first drying area section;
A second drying region portion for drying the web stretched by the stretching portion;
With
The first drying region portion is at least perpendicular to the short direction while sucking and / or sandwiching a portion of the web excluding at least the central portion in the short direction and including the vicinity of both ends. Having a drive roll for conveying in the longitudinal direction of the web;
The manufacturing apparatus of the film in which the said drive roll has the surface of the mirror surface state which contacts the said center part.

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