JP5862687B2 - Manufacturing method of long stretched film - Google Patents

Description

  The present invention relates to a method for producing a long stretched film.

  A stretched film formed by stretching a resin is used as an optical film that performs various optical functions in various display devices by utilizing its optical anisotropy. For example, in a liquid crystal display device, the stretched film is used as an optical compensation film for optical compensation such as anti-coloring and viewing angle expansion, or by bonding the stretched film and a polarizer, It is known to use as a retardation film that also serves as a polarizing plate protective film.

  On the other hand, in recent years, a self-luminous display device such as an organic electroluminescence display device has attracted attention as a new display device. Self-luminous display devices have room to reduce power consumption compared to liquid crystal display devices in which the backlight is always lit. Further, self-luminous display devices such as organic electroluminescence display devices are lit with light sources corresponding to respective colors. In the light emitting display device, since it is not necessary to install a color filter that causes a reduction in contrast, the contrast can be further increased.

  However, in an organic electroluminescence display device, a reflector such as an aluminum plate is provided on the back side of the display in order to increase the light extraction efficiency, and external light incident on the display is reflected by this reflector so that an image is displayed. There arises a problem that the contrast is lowered. For this reason, a technique is known in which a stretched film and a polarizer are bonded to each other and a circularly polarizing plate is used on the surface side of the display in order to improve contrast of light and darkness by preventing external light reflection.

  Such a circularly polarizing plate needs to be bonded in such an arrangement that the in-plane slow axis of the stretched film is inclined at a desired angle with respect to the transmission axis of the polarizer.

  However, a general polarizer (polarizing film) is obtained by stretching at a high magnification in the transport direction, and its absorption axis coincides with the transport direction, and the conventional retardation film is longitudinally stretched, or Manufactured by transverse stretching, the in-plane slow axis is in principle 0 ° or 90 ° with respect to the longitudinal direction of the film. For this reason, in order to make the relationship between the absorption axis of the polarizer and the slow axis of the stretched film a desired angle as described above, a long polarizing film and / or a stretched film is cut out at a specific angle. A batch method in which the pieces are bonded one by one has to be performed, and problems such as deterioration in productivity due to variations in slow axis and reduction in product yield due to adhesion of chips and the like have been cited as problems.

  Therefore, in Patent Document 1, production of a long retardation film that is stretched obliquely at a desired angle and whose slow axis is freely controllable in a direction that is neither 0 ° nor 90 ° with respect to the longitudinal direction of the film. A method has been proposed. By this method, the polarizing film and the stretched film can be bonded to each other by roll-to-roll, so that the yield is not reduced and stable production can be performed.

  However, when high-speed production / thin film quality products were produced by the above-described obliquely stretched film forming method, there was a problem that scratches and dents were generated in the stretched film when the appearance quality of the finished film was evaluated. When this is incorporated in the above-described display device, there is a problem that the product cannot be manufactured, such as generation of spot-like color leakage.

International Publication No. 2007/111313

  The purpose of the present invention is to reduce film pieces and debris that adhere to the film at the time of slitting at both ends of a long stretched film by oblique stretching, while preventing flaws from sticking to the film surface and suppressing the risk of production stoppage. An object of the present invention is to provide a method for producing a long stretched film capable of securing a sufficient product width.

  When this problem was investigated, it was found that the position where the flaws and dents were generated was after the slit process for cutting the film edge. As a countermeasure against this, it was found that when the cutting width of the slit was changed, scratches and dents were improved if the cutting width was widened, and on the contrary, if the cutting width was narrowed, the scratches and dents were worsened. Generally, in a film manufacturing method in which an end portion is gripped and stretched, the end portion of the film gripped by a clip or the like is deformed by the clip gripping and cannot be used as a product. It is necessary to cut and remove with a cutting tool called. However, if the cutting width is wide enough to eliminate scratches and dents, an effective film width as a product cannot be secured, which is a new problem.

  As a result of further investigation, it was discovered that the cut cross section of the film on the inner peripheral side in the oblique stretching apparatus was rougher, and the occurrence of scratches and dents was also remarkable on the inner peripheral side. As a result of examination of the factors, it was found that the above-mentioned problem occurs when slitting a film stretched obliquely.

  On the other hand, in a method of stretching obliquely by a stretching device having a different film feeding direction and winding direction as described in Patent Document 1, the inner circumference side (the side that is held short by the gripping tool) Is preceded at the time of stretching, it is possible to obtain a film in which the film is stretched obliquely and the resin constituting the film is obliquely oriented and the slow axis is obliquely oriented. At that time, on the inner peripheral side, the orientation direction of the resin (molecules) is inclined to the downstream side in the film transport direction. In addition, since it is strongly pulled in the transport direction in the vicinity of the end portion gripped by the gripping tool, the resin is oriented in a direction further inclined to the downstream side in the transport direction as compared with the central portion of the film. When the resin of the film is greatly inclined to the downstream side in the film transport direction, the resin film exhibits a characteristic of being easily torn in the orientation direction, so when applying the cutting force from the film traveling direction, the cutting force or cutting When a minute vibration of the film occurs, tearing and roughening are likely to occur at the end.

  On the other hand, on the outer peripheral side (the side on which the length gripped by the gripping tool is long), a force is generated that pulls the film upstream in the transport direction during oblique stretching, so the resin near the film end is upstream in the film transport direction. The inclination to For this reason, it is difficult for the outer peripheral side to tear or rough the cut surface during cutting. Therefore, when the same width is cut from the end portion by the slitter, the inner peripheral side is easily torn, and the problems such as scratches and dents are increased by the film pieces generated from the end portion.

  Even in a method for producing a stretched film that stretches a general film laterally, a phenomenon called so-called bowing occurs in which the center of the film slightly bends in the upstream side in the transport direction, and the end portion slightly extends in the transport direction of the film. Although it may incline to the downstream side, it is slight, and the problem at the time of the slit as described above has not been recognized.

  As a result of intensive studies to achieve the above object, the present inventor has reduced the number of film pieces and debris adhering during the slitting process and prevented the adhesion of scratches to the surface by the following configuration. It has been found that a method for producing a long stretched film capable of securing a sufficient product width can be obtained, and the present invention has been completed.

That is, the manufacturing method of the long stretched film which concerns on 1 aspect of this invention is the process different from the winding direction of the film after extending | stretching the said long film, the process which forms the long film containing a thermoplastic resin The long film is extended from 0 ° to less than 90 ° with respect to the width direction while the both ends of the long film in the width direction are gripped and conveyed by the gripping tool of the obliquely stretched tenter. Long stretch having at least a step of obliquely stretching in the direction, a slit step of cutting both ends of the long film after the oblique stretch step with a slit device, and a step of winding the long stretched film after the slit step In the film manufacturing method, in the slit step, the cutting width on the inner peripheral side of the end of the long stretched film is larger than the cutting width on the outer peripheral side. It is characterized by cutting. In the slitting process, the inner peripheral side of the long stretched film is cut under conditions of a higher temperature than the outer peripheral side .

  That is, according to the present invention, the inner peripheral side is cut so as to avoid a position where the inclination of the end portion is large, in addition to cutting a portion due to the deformation of the grip portion in the same manner as normal stretching, and the outer peripheral side Providing a method for producing a long stretched film capable of producing a high quality film even under a thin film / high film forming speed by ensuring the product width by narrowing the cutting width from the inner peripheral side. Is possible.

  The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

Schematic diagram of film orientation distribution when cutting horizontally stretched film or obliquely stretched film Schematic top view showing the configuration of the oblique stretching device Schematic side view showing the configuration of the oblique stretching device Schematic which shows an example of the rail pattern of the diagonally stretched tenter used for the manufacturing method of the elongate stretched film which concerns on embodiment of this invention. Schematic showing the configuration of the slit process Schematic which shows an example of a structure of an organic electroluminescent image display apparatus. Diagram showing the synthesis of sugar ester compounds

  The present inventors have found and studied that the cause of trouble in oblique stretching film formation as described above is in the orientation angle direction of the film in the case where the film is formed by changing the oblique angle.

  Fig.1 (a) is the schematic of the film orientation distribution at the time of cut | disconnecting the film stretched laterally. The central part of the film is horizontally oriented by lateral stretching, but the end of the film is inclined several degrees from the central part of the film due to bowing (becomes a bow). Therefore, as the cutting width in this case, as shown by the wavy arrow in FIG. 1A, the film is slit using a slitting device or the like from the opposite side of the conveying direction so as to leave several tens of mm from the range satisfying the product standard. It is common to do.

  Then, the schematic of the film orientation distribution at the time of cut | disconnecting the film which carried out the above-mentioned diagonal stretch film forming in FIG.1 (b) is shown. In each case, the right side of the film in FIG. 1B is the inner side during oblique stretching, and the left side is the outer side. In this case, since the orientation direction of the film is inclined, the film has a characteristic of being easily torn in an oblique direction, and is more easily torn than in the case of cutting the laterally stretched film. In particular, when cutting the film inner side (slits 3, 4), since it has a characteristic that it is easy to tear to the film side when viewed from the cutting direction side compared to the case of cutting the film outer side (slits 1, 2), In particular, the film productivity is easily affected. Furthermore, since the slit 4 is a position having a larger inclination than the slit 3 due to the influence of bowing, the film is likely to tear due to minute vibrations and angular deviation of the slit.

  As described above, when cutting both ends of the obliquely stretched film, film pieces and debris due to insufficient cutting of the film adhere to the slit portion, and the debris rises during the cutting, so that the film pieces and debris rise. Is transported while adhering to the film. For this reason, there is a problem in that the roll being transported and the film are rubbed, and the film surface is scratched. In addition, the film ends after the slits are torn, and the film is eventually broken to stop the film formation.

  In particular, when the inclination angle in the stretching direction becomes large with respect to the width direction of the film, the frequency of occurrence of the above problems has increased. Further, when the film production speed is increased, the stretching stress increases and the orientation angle on the film end side is further inclined, so that the above problem is more likely to occur. In addition, even when the film is thinned, the above-mentioned problems are likely to occur because the film physical properties are weakened.

  The present invention has been completed as a result of studies to solve such problems.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

  Below, the manufacturing method of the elongate stretched film which concerns on this embodiment is demonstrated.

<Method for producing long stretched film>
The method for producing a long stretched film of the present invention includes a step of forming a long film containing a thermoplastic resin, the long film is fed out from a specific direction different from the winding direction of the film after stretching, A slanting film that obliquely stretches the long film in a direction greater than 0 ° and less than 90 ° with respect to the width direction while holding and transporting both ends in the width direction of the long film with a gripping tool of an oblique stretching tenter. In the method for producing a long stretched film having at least a stretching step, a slit step of cutting both ends of the long film after the oblique stretching step with a slitting device, and a step of winding the long stretched film after the slit step, In the slitting process, the cutting is performed such that the cutting width on the inner peripheral side of the end of the long stretched film is larger than the cutting width on the outer peripheral side. The

  Here, the inner peripheral side indicates the shorter travel distance of the gripping tool, and the outer peripheral side indicates the longer travel distance of the gripping tool. Here, FIG. 4 is a schematic diagram showing the rail pattern of the obliquely stretched tenter, where the left and right gripping tools Ci and Co are positioned at the end of stretching from the obliquely stretched tenter entrance (position A in FIG. 4) (in FIG. 4). Travel on asymmetric rails Ri, Ro connecting to B). Since the rail pattern of FIG. 4 is a case of turning to the left, the inner peripheral side is the rail Ri side, and the outer peripheral side is the Ro side. Further, when the rail pattern turns to the right, Ri and Ro change in the opposite direction.

  Here, the “long” means a film having a length of at least about 5 times the width of the film, preferably a length of 10 times or more, and specifically wound in a roll shape. And a length (film roll) that can be stored or transported.

  The present invention can also be applied to a case where slitting is performed when rewinding is performed again after a step of winding without slitting after the oblique stretching step.

  2 and 3 are diagrams schematically showing an oblique stretching apparatus used in each step of the method for producing a long stretched film according to an embodiment of the present invention. However, this is an example, and the present invention is not limited to this.

  2 and 3, reference numerals represent the following members, devices, and the like. DESCRIPTION OF SYMBOLS 1 Diagonal stretching apparatus, 2 Diagonal stretching tenter, 3 Film feeding apparatus, 4 Film winding apparatus, 5, 8 Conveyance roll, 6 Inner guide rail, 7 Outer guide rail, 9 Inner slit blade, 10 Outer slit blade 11, 12 Guide rail start position, 13, 14 Guide rail end position, 15 Long film (long stretched film).

  Hereafter, each process of the film forming method of this invention is demonstrated.

[Film forming process]
The film forming step according to the production method of the present invention is a step of forming a long film containing a thermoplastic resin. The film forming step is performed by various means depending on the type of the thermoplastic resin, and the details will be described later.

[Diagonal stretching process]
The oblique stretching step according to the production method of the present invention is such that the film is unwound from a film unwinding device from a specific direction different from the film winding direction after stretching, and the both ends of the long film in the width direction are gripped by the oblique stretching tenter. This is a step of providing an in-plane slow axis at an arbitrary angle greater than 0 ° and less than 90 ° with respect to the width direction of the film by obliquely stretching the film while being held and conveyed by a tool.

  Here, the angle with respect to the width direction of the film is an angle in the film plane. Since the slow axis is usually expressed in the stretching direction or a direction perpendicular to the stretching direction, in the production method according to the present invention, an angle of more than 0 ° and less than 90 ° with respect to the direction perpendicular to the film transport direction, A stretched film having such a slow axis can be produced by stretching at a desired angle.

(Feeding device)
As shown in FIGS. 2 and 3, the film feeding device 3 can be slid and swiveled so that the film can be fed at a predetermined angle with respect to the obliquely stretched tenter inlet. The film feeding device 3 is slidable, and it is preferable that the film can be fed to the entrance of the obliquely stretched tenter by the transport direction changing device. By making the film feeding device 3 and the transport direction changing device in such a configuration, it becomes possible to finely control the feeding position and angle of the film, and to produce a long stretched film with small variations in film thickness and optical value. Can be obtained. In addition, by making the film feeding device 3 and the transport direction changing device movable, it is possible to effectively prevent a gripping tool from being caught in the film.

(Transport roll)
The transport roll 5 is a roll that sends the film fed from the feeding device to the guide rail start positions 11 and 12.

  The number of the transport rolls 5 is not particularly specified, and a slitter process for cutting the film end part in the middle of arranging the transport rolls may be provided. Moreover, you may provide the static elimination apparatus for neutralizing a film before and behind arrangement | positioning of a conveyance roll, or between several conveyance rolls. The said static elimination apparatus can use the same thing as the static elimination apparatus used by the slit process demonstrated later.

(Obliquely stretched tenter)
In the manufacturing method according to this embodiment, an obliquely stretched tenter is used to impart an oblique orientation to the long film. The oblique stretching tenter used in the present embodiment is preferably a film stretching apparatus that can freely set the orientation angle of the film by variously changing the rail pattern. Furthermore, it is preferable that the film stretching apparatus is capable of highly accurately orienting the orientation axis of the film across the width direction of the film and controlling the film thickness and retardation with high precision.

  FIG. 4 is a schematic view showing an example of a rail pattern of an obliquely stretched tenter used in the method for producing a long stretched film according to an embodiment of the present invention. However, this is an example, and the present invention is not limited to this.

  The feeding direction D1 of the long film is different from the winding direction D2 of the long stretched film after stretching, and forms a feeding angle θi. The feeding angle θi can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.

  The long film is gripped by the right and left gripping tools at the obliquely stretched tenter entrance (position A in FIG. 4) and travels as the gripping tool travels. The left and right gripping tools are diagonally stretched tenter inlets (position A in FIG. 4), and the left and right gripping tools Ci and Co that are opposed to a direction substantially perpendicular to the film traveling direction (feeding direction D1) are: The film travels on the left and right asymmetric rails Ri and Ro, and the film gripped at the position at the end of stretching (position B in FIG. 4) is released.

  At this time, as the left and right gripping tools facing each other at the obliquely extending tenter entrance (position A in FIG. 4) travel on the asymmetrical rails Ri and Ro, the gripping tool Ci traveling on the Ri side becomes Ro The positional relationship is advancing with respect to the gripping tool Co traveling on the side.

  That is, the gripping tools Ci and Co that are opposed to the direction D1 of the film at the oblique stretching tenter entrance (the gripping start position by the film gripping tool) A are positioned at the position B when the film stretching ends. In a certain state, a straight line connecting the grippers Ci and Co is inclined by an angle θL with respect to a direction substantially perpendicular to the film winding direction D2.

  With the above operation, the long film is obliquely stretched in the direction of θL. Here, “substantially vertical” indicates that the angle is in a range of 90 ± 1 °.

  The obliquely stretched tenter can heat the long film to any temperature at which it can be stretched. The diagonally stretched tenter includes a heating zone, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rail. Both ends of the film sequentially supplied to the entrance portion of the tenter are gripped by a gripping tool, the film is guided into the heating zone, and the film is released from the gripping tool at the exit portion of the tenter. The film released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the exit portion of the tenter travels outside and is sequentially returned to the entrance portion.

  In addition, the rail pattern of the tenter has an asymmetric shape on the left and right, so that the rail pattern can be adjusted manually or automatically according to the orientation angle θ, the draw ratio, etc. given to the long stretched film to be manufactured. It has become. In the obliquely stretched tenter used in the manufacturing method according to the embodiment of the present invention, it is preferable that the position of each rail portion and the rail connecting portion can be freely set and the rail pattern can be arbitrarily changed.

  In the embodiment of the present invention, the tenter gripping tool travels at a constant speed with a constant distance from the front and rear gripping tools.

  The traveling speed of the gripping tool can be selected as appropriate, but is usually 1 to 150 m / min. Under high-speed production conditions, the inclination of the orientation angle on the inner peripheral side becomes larger, so the problem of scratches and dents at the time of slitting becomes more prominent. Therefore, when the present invention is implemented in a range where the traveling speed is 25 to 150 m / min, the effect of the present invention can be further improved. When the present invention is implemented in a range where the traveling speed is 50 to 150 m / min, the effect of the present invention is achieved. Can be further improved.

  The difference in travel speed between the pair of left and right grippers is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed between the left and right sides of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the right and left gripping tools is required to be substantially the same speed. Because. In general tenter devices, etc., there are speed irregularities that occur in the order of seconds or less depending on the period of the sprocket teeth that drive the chain, the frequency of the drive motor, etc. This does not correspond to the speed difference described in the embodiment of the invention.

  In the obliquely stretched tenter used in the manufacturing method according to the embodiment of the present invention, a high bending rate is often required for the rail that regulates the trajectory of the gripping tool, particularly in a portion where the film is transported obliquely. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws a curve at the bent portion.

  In the embodiment of the present invention, the long film is sequentially gripped by the left and right gripping tools at the obliquely stretched tenter entrance (position A in FIG. 4), and travels as the gripping tool travels. The left and right gripping tools facing the direction substantially perpendicular to the film traveling direction D1 at the oblique stretching tenter entrance (position A in FIG. 4) run on the left and right asymmetric rails, and the preheating zone and stretching zone Through a heating zone having a heat setting zone.

  The preheating zone refers to a section that travels while maintaining a constant interval between the gripping tools that grip both ends at the entrance of the heating zone.

  In addition, the stretching zone refers to a section in which the interval between the gripping tools gripping both ends starts to reach a predetermined interval.

  At this time, the oblique stretching as described above is performed, but the stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching as necessary.

  The heat setting zone refers to a section in which the gripping tools at both ends run in parallel with each other in a period in which the interval between the gripping tools after the stretching zone becomes constant again.

  You may pass through the area (cooling zone) by which the temperature in a zone is set to below the glass transition temperature Tg degreeC of the thermoplastic resin which comprises a film, after passing through a heat setting zone.

  At this time, in consideration of shrinkage of the film due to cooling, a rail pattern that narrows the gap between the opposing grippers in advance may be used.

  The temperature of each zone is Tg to Tg + 30 ° C., the temperature of the stretching zone (stretching temperature) is Tg to Tg + 30 ° C., and the temperature of the cooling zone is Tg-30 to Tg of the glass transition temperature Tg of the thermoplastic resin. It is preferable to set to Tg ° C.

  In order to control the thickness unevenness in the width direction, a temperature difference may be given in the width direction in the stretching zone. In order to create a temperature difference in the width direction in the stretching zone, a method of adjusting the opening degree of the nozzle for sending warm air into the temperature-controlled room so as to make a difference in the width direction, or controlling the heating by arranging the heaters in the width direction is known. Can be used. The length of the preheating zone, the stretching zone and the cooling zone can be appropriately selected. The length of the preheating zone is usually 100 to 150% and the length of the fixed zone is usually 50 to 100% with respect to the length of the stretching zone. .

  The draw ratio (W / W0) in the oblique stretching step is preferably 1.3 to 3.0, more preferably 1.5 to 2.8. If the draw ratio is in this range, thickness unevenness in the width direction is reduced, which is preferable. In the stretching zone of the oblique stretching tenter, if the stretching temperature is differentiated in the width direction, the thickness unevenness in the width direction can be further improved. W0 represents the width of the film before stretching, and W represents the width of the film after stretching.

[Slit process]
The slit process which concerns on the manufacturing method of this invention is a process of cut | disconnecting the both ends of the elongate stretched film after the diagonal stretch process mentioned later with a slit apparatus.

  Since both ends of the long stretched film are deformed by the gripping tool in an oblique stretching process described later, it is necessary to excise both end portions whose shapes are unstable. Moreover, in the slit process of this invention, it is necessary to cut | disconnect so that the cutting width in the inner peripheral side of a long stretched film edge part may become larger than the cutting width in an outer peripheral side.

  The cutting width is the distance from the extreme end in the width direction of the long stretched film to the position to be cut.

  In the production method of the present invention, the slitting process is not particularly limited as long as it is a process of cutting so that the cutting width on the inner peripheral side of the long stretched film is larger than the cutting width on the outer peripheral side. It is preferable to have.

  FIG. 5 is a schematic view showing the configuration of one embodiment of the slitting process of the present invention.

  The slit device of the present embodiment is a device that cuts both ends of the long stretched film 15 in a direction along the transport direction (the arrow F direction in FIG. 5).

  Two slit devices are arranged on the extension lines of the inner guide rail 6 and the outer guide rail 7 of the obliquely extending tenter 2, respectively. Further, the inner slit device is a circular shape for supporting the upper blade 9a disposed on the upper side inside the long stretched film 15, the lower blade 9b disposed on the lower side, and the long stretched film 15 from the lower side. A support member (not shown) is provided. Similarly, the outer slit device supports the upper blade 10a disposed on the upper side inside the long stretched film 15, the lower blade 10b disposed on the lower side, and the long stretched film 15 from the lower side. A circular support member (not shown) is provided.

  The upper blade 9a (10a) and the lower blade 9b (10b) are circular blades that are rotatably supported. Here, the upper blade 9a (10a) is rotatably supported so as to be passively rotated according to the conveyance of the long stretched film 15, and the lower blade 9b (10b) is elongated by a drive motor (not shown). It is driven to rotate in accordance with the conveyance of the long stretched film 15 so as to coincide with the conveyance speed of the film 15. However, these are opposite, that is, the lower blade 9b (10b) is rotatably supported so as to passively rotate according to the conveyance of the long stretched film 15, and the upper blade 9a (10a) is driven by a drive motor (not shown). You may make it rotationally drive in the reverse rotation direction with respect to conveyance of the elongate stretched film 15 so that it may correspond with the conveyance speed of the elongate stretched film 15 roughly.

  Further, both the upper blade 9a (10a) and the lower blade 9b (10b) may be rotationally driven so as to substantially coincide with the conveying speed of the long stretched film 15, or both may be rotated without being rotationally driven. You may make it support freely. Further, one or both of the upper blade 9a (10a) and the lower blade 9b (10b) may be driven in reverse rotation.

  The upper blade 9a (10a) and the lower blade 9b (10b) may be so-called dish-shaped blades, saddle-shaped blades, or other shapes of circular blades. Here, the upper blade 9a (10a) is a dish-shaped blade. The lower blade 9b (10b) is a saddle blade. The material of the upper blade 9a (10a) and the lower blade 9b (10b) may be made of metal or ceramic, but it is preferable to use cemented carbide or high-speed steel. From the viewpoint of the amount of cut residue generated and the smoothness of the cut surface, it is preferable to use a cemented carbide blade made of a cemented carbide. The upper blade 9a (10a) has a diameter of about 90 mm to 150 mm and a thickness of about 1 mm to 5 mm. The diameter of the lower blade 9b (10b) is about 90 mm to 150 mm, and the thickness is about 1 mm to 10 mm.

  The conveyance speed at the time of cutting by the mechanism can be appropriately selected depending on the film forming conditions, and it is preferably carried out in the range of 1 to 150 m / min.

  In order to divide the long stretched film 15 into a plurality along the transport direction to form a narrow long stretched film, the slit device may be further provided at a single or a plurality of locations inside.

  Next, the cutting width of the present invention cut by the slitting device will be described.

  The end of the film in film formation by normal transverse stretching or longitudinal stretching is deformed by gripping the clip and cannot be used as a product, so it must be discarded. The cutting width is generally set to be slightly wider than the width that can be effectively used as a product without deformation of the grip portion.

  However, the cutting width on the inner peripheral side in the obliquely stretched film formation of the present invention is preferably cut at a position avoiding the position where the inclination of the orientation is steep from the deformed portion.

  The width in which the inclination of the orientation is steep is appropriately changed depending on the stretching conditions of the film, so that the cutting width can be appropriately selected within a range in which the film does not have scratches or dents. The cutting width when the film width after stretching is in the range of 500 mm to 3000 mm is preferably 55 mm to 350 mm, and more preferably 85 mm to 250 mm.

  On the outer peripheral side, there is no problem of defective slits due to the large inclination of the orientation angle as on the inner peripheral side, so it is sufficient to cut only the part that has been deformed by gripping the clip, and the cutting width on the inner peripheral side It can be appropriately selected depending on the stretching conditions so as to be narrower.

  The cutting width on the outer peripheral side is preferably 50 mm to 250 mm, more preferably 80 mm to 150 mm, when the film width after stretching is in the range of 500 mm to 3000 mm.

  By setting it as the above cutting width structure, it can manufacture without the deterioration of external appearance quality, such as a crack and a dent, ensuring the effective film width used as a product.

  Moreover, in the slit process of this invention, it is preferable to cut | disconnect the inner peripheral side of a elongate stretched film on the conditions of temperature higher than an outer peripheral side. In other words, by heating the film position where the slit blade hits before the inner peripheral side slit blade contacts the film, it becomes possible to perform cutting of the long stretched film on the inner peripheral side under high temperature conditions, Film pieces and debris are less likely to adhere to the slit blade.

  It is preferable that the temperature is adjusted by heating with a heat generator before cutting. The heat generator is not particularly limited as long as the resin film to be conveyed can be heated to a predetermined temperature. For example, an infrared heater is used, or heated constant temperature air is circulated to obtain a predetermined temperature. Good.

  The temperature is preferably adjusted by adjusting the elapsed time from the oblique stretching step. The temperature during the oblique stretching step is performed under the condition of Tg-30 to Tg + 30 ° C., and then the substrate is conveyed in the region temperature set near room temperature. Therefore, if it adjusts so that the film edge part of an inner peripheral side may be cut | disconnected earlier than the film edge part of an outer peripheral side, a long stretched film can be cut | disconnected on the conditions of high temperature. As a result, film pieces and debris are less likely to adhere to the slit blades when cutting on the inner peripheral side of the film.

  It is preferable that the slit device has a mechanism that follows in accordance with the stretching direction of the long stretched film. In the oblique stretching tenter described later, the stretching direction and the winding direction can be arbitrarily set in order to obtain a long stretched film in which the orientation axis has an inclination as required with respect to the width direction of the film. Therefore, the slit device of the present invention is also required to have a mechanism that operates following the conveyance in the stretching direction and the winding direction.

  Thus, when the slit device has the following mechanism, both ends of the long stretched film can be easily cut. In particular, when the cutting width on the inner peripheral side and the cutting width on the outer peripheral side are different as in the present invention, the slit device is removed or reconstructed when changing the inclination angle in the stretching direction and the winding direction. This eliminates the need to perform such a process, resulting in excellent productivity.

  As a specific example of the following mechanism, for example, the guide roll end positions of 13 and 14 including the slitter devices of transport rolls 8 and 9 and 10 to 4 winding devices are fixed on a movable plate shape. Or fixed on a movable rail, and a single movable unit. That is, there is a method such as allowing the movement from the terminal position of the guide rails 13 and 14 to the winding device 4 to move together, but is not particularly limited.

  Moreover, it is preferable that the said slit apparatus has a mechanism which can confirm the position of the angle of the extending direction of the said elongate stretched film, and the advancing direction of a slit blade. By having such a confirmation mechanism, the slit device can be more easily operated with conveyance in the stretching direction.

  As a specific example of the confirmation mechanism, a light source is installed in the slitter unit, and a sensor installed in 4 winding devices or 2 heating zones detects the light from the light source to confirm the position. is there. The light source may be a commercially available one such as a laser, and is not particularly limited.

  The slit device may be provided between the transport rolls 8 as shown in FIGS. 2 and 3, and may be installed anywhere between the transport rolls 8.

  The number in particular of the said conveyance roll 8 is not prescribed | regulated, You may provide the process of sticking the protective sheet which protects a elongate stretched film in the middle of arrangement | positioning of a conveyance roll. Moreover, before winding up a film, you may provide the process of giving a embossing part (not shown) to a film edge part by giving a knurling process to the film right and left both ends by an embossing ring and a back roll.

  In the middle of the arrangement of the transport rolls, a film thickness meter or an optical value measuring machine capable of online measurement may be arranged. Moreover, you may provide the static elimination apparatus for neutralizing a long stretched film before and behind arrangement | positioning of a conveyance roll, or between several conveyance rolls. The static eliminator can be configured to apply a reverse potential by the static eliminator or the forced charging device at the time of winding so that the charging potential when the original winding is redrawn is ± 2 kV or less. It can also be set as the structure which static-eliminates with the static elimination device converted into positive / negative alternately at 1-150Hz. Moreover, it can replace with said static elimination device and can utilize the ionizer and static elimination bar which generate | occur | produce ion wind. Here, the ionizer static elimination is performed by blowing an ion wind toward the film wound up from the embossing device via the transport roll. The ion wind is generated by a static eliminator. Any known static eliminator can be used without limitation.

[Winding process]
The winding process which concerns on the manufacturing method of this invention is a process of winding up the elongate stretched film after the said slit process. Below, the winding apparatus used for a winding process is demonstrated.

(Winding device)
As shown in FIGS. 2 and 3, the take-up device 4 can be finely controlled for the film take-up position and angle by forming the take-up device 4 so that the film can be taken at a predetermined angle with respect to the obliquely stretched tenter outlet. Thus, it is possible to obtain a long stretched film with small variations in film thickness and optical value. Therefore, the generation of wrinkles in the film can be effectively prevented, and the winding property of the film is improved, so that the film can be wound up in a long length.

  In the present embodiment, the take-up tension T (N / m) of the stretched film is preferably adjusted between 100 N / m <T <300 N / m, preferably 150 N / m <T <250 N / m. . When the take-up tension is 100 N / m or less, sagging and wrinkles of the film are likely to occur, and retardation and the profile in the width direction of the orientation axis are also deteriorated. On the other hand, when the take-up tension is 300 N / m or more, the variation in the orientation angle in the width direction is deteriorated, so that the width yield (taken efficiency in the width direction) is deteriorated.

  In the present embodiment, it is preferable to control the fluctuation of the take-up tension T with an accuracy of less than ± 5%, preferably less than ± 3%. When the fluctuation of the take-up tension T is ± 5% or more, the variation in the optical characteristics in the width direction and the flow direction becomes large. As a method for controlling the fluctuation of the take-up tension T within the above range, general PID control is performed so that the load applied to the first roll at the tenter outlet, that is, the film tension is measured and the value is kept constant. A method of controlling the rotation speed of the take-up roll by a method is mentioned. Examples of the method for measuring the load include a method in which a load cell is attached to a bearing portion of a roll and a load applied to the roll, that is, a film tension is measured. As the load cell, a known tensile type or compression type can be used.

  The stretched film is released from the tenter outlet after being gripped by the gripper, cut off at both ends (both sides) of the film, and then wound around a winding core (winding roll) in order to be a long stretched film The wound body can be made. Moreover, the winding process of the present invention may be rewound again after being wound without passing through the slit process of the present invention, and at that time, the slitting process of the present invention can also be performed.

  Further, before winding, for the purpose of preventing blocking between the films, the masking film may be overlapped and wound up at the same time, or at least one of the long stretched films, preferably while winding tape or the like on both ends. You may take it. The masking film is not particularly limited as long as it can protect the film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

  The static elimination at the time of film-forming winding may use the static elimination method and the static elimination apparatus described in the slit process.

[Thermoplastic resin and film forming method]
As the thermoplastic resin that can be used in the present embodiment, polycarbonate resin, polyether sulfone resin, polyethylene terephthalate resin, polyimide resin, polymethyl methacrylate resin, polysulfone resin, polyarylate resin, Examples thereof include polyethylene resins, polyvinyl chloride resins, olefin polymer resins having an alicyclic structure, and cellulose ester resins.

  Among these, polycarbonate resins, olefin polymer resins having an alicyclic structure, and cellulose ester resins are preferable from the viewpoints of transparency and mechanical strength. Among them, an olefin polymer-based resin and a cellulose ester-based resin having an alicyclic structure, which can easily adjust the phase difference when an optical film is used, are more preferable.

  Below, the structure about the olefin polymer-type resin and cellulose-ester-type resin which have an alicyclic structure, and the film forming method of the elongate film each containing these are shown.

(Olefin polymer resin)
Examples of alicyclic olefin polymer resins include cyclic olefin random multi-component copolymers described in JP-A No. 05-310845, hydrogenated polymers described in JP-A No. 05-97978, and JP-A No. 11 And thermoplastic dicyclopentadiene ring-opening polymer and hydrogenated product thereof described in JP-A-124429.

  The olefin polymer resin having an alicyclic structure will be described more specifically. The alicyclic olefin polymer resin is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable.

  The proportion of the repeating unit containing the alicyclic structure in the alicyclic olefin polymer may be appropriately selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it. If the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is within this range, the transparency and heat resistance of an optical material such as a long stretched film obtained from the stretched film of the present invention are improved. preferable.

  Examples of olefin polymer resins having an alicyclic structure include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. it can. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. An addition polymer of a monomer having a monomer, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly preferable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, and lightness. It can be used suitably.

  Monomers having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.12,5] deca-3,7-diene ( Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.12,5] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0.12, 5.17,10] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; and cyclic such as cyclohexadiene and cycloheptadiene. And conjugated dienes and derivatives thereof.

  A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Other monomers capable of addition copolymerization with a monomer having a norbornene structure include, for example, ethylene, propylene, α-olefins having 2 to 20 carbon atoms such as 1-butene and derivatives thereof; cyclobutene, cyclopentene And cycloolefins such as cyclohexene and derivatives thereof; and non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 5-methyl-1,4-hexadiene. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

  An addition polymer of a monomer having a norbornene structure and an addition copolymer of a monomer having a norbornene structure with another monomer copolymerizable with a monomer having a norbornene structure are prepared in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  A hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, a hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and another monomer capable of ring-opening copolymerization thereof, Hydrogenated products of addition polymers of monomers having a norbornene structure, and hydrogenated products of addition copolymers of monomers having a norbornene structure and other monomers copolymerizable therewith It can be obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to the polymer solution and hydrogenating carbon-carbon unsaturated bonds, preferably 90% or more.

  Among norbornene-based resins, as a repeating unit, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.12,5] decane-7, 9-diyl-ethylene structure, the content of these repeating units is 90% by weight or more with respect to the entire repeating unit of the norbornene-based resin, and the content ratio of X and the content ratio of Y It is preferable that the ratio is 100: 0 to 40:60 by weight ratio of X: Y. By using such a resin, the optical material obtained from the stretched film of the present invention can be made long-term without dimensional change and excellent in optical property stability.

  The molecular weight used for the norbornene-based resin is appropriately selected according to the purpose of use, but is converted to polyisoprene measured by gel permeation chromatography using cyclohexane (toluene if the thermoplastic resin does not dissolve) as the solvent (the solvent is In the case of toluene, it is a weight average molecular weight (Mw) in terms of polystyrene, and is usually 10,000 to 100,000, preferably 15,000 to 80,000, more preferably 20,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the optical material obtained by the stretched film of the present invention are highly balanced and suitable.

  The glass transition temperature of the norbornene-based resin may be appropriately selected depending on the purpose of use, but is preferably 80 ° C. or higher, more preferably in the range of 100 to 250 ° C. When the glass transition temperature is in such a range, the optical material obtained by the stretched film of the present invention can be made excellent in durability without causing deformation or stress in use at high temperatures.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the norbornene resin is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 4.0, more preferably 1. The range is from 2 to 3.5.

The absolute value of the photoelastic coefficient C of norbornene-based resin is preferably ¹⁰ × 10 -12 ^{Pa -1} or less, more preferably 7 × ¹⁰ -12 ^{Pa -1} or less, 4 × ¹⁰ -12 Pa Particularly preferably, it is ⁻¹ or less. The photoelastic coefficient C is a value represented by C = Δn / σ where birefringence is Δn and stress is σ. When the photoelastic coefficient of the thermoplastic resin is in such a range, the variation in retardation (Re) in the in-plane direction, which will be described later, can be reduced.

  The thermoplastic resin used in the present invention includes colorants such as pigments and dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, and the like. These compounding agents may be appropriately blended.

  The content of the residual volatile component in the stretched film of norbornene resin is not particularly limited, but is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. is there. By setting the content of the volatile component in such a range, the dimensional stability can be improved, the change with time of Re and Rth can be reduced, and the optical film obtained from the stretched film of the present invention. The deterioration of the polarizing plate or the organic electroluminescence display device can be suppressed, and the display on the display device can be stably and satisfactorily maintained for a long time. The residual volatile component is a substance having a molecular weight of 200 or less contained in a trace amount in the film, and examples thereof include a residual monomer and a solvent. The content of residual volatile components can be quantified by analyzing the film by gas chromatography as the sum of the substances having a molecular weight of 200 or less contained in the film.

  The saturated water absorption of the stretched film of norbornene resin is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, and particularly preferably 0.01% by weight or less. If the saturated water absorption is in the above range, the change with time of Re and Rth can be reduced, and further, deterioration of the optical film, polarizing plate or organic electroluminescence display device obtained from the stretched film of the present invention can be suppressed, The display on the display device can be kept stable and good for a long time.

  Saturated water absorption is a value expressed as a percentage of the mass of the test piece before immersion, after the test piece of the film is immersed in water at a constant temperature for a fixed time. Usually, it is measured by immersing in 23 ° C. water for 24 hours. The saturated water absorption rate in the stretched film of the present invention can be adjusted to the above value by, for example, reducing the amount of polar groups in the thermoplastic resin, but is preferably a resin having no polar groups. Is desired.

(Film forming method of olefin polymer resin)
As a method for forming a film using the preferred norbornene-based resin described above, a solution casting method or a melt extrusion method is preferred. Examples of the melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

  The extrusion molding method using a T-die is a method for maintaining retardation and orientation by a method of keeping a molten thermoplastic resin in a stable state when closely contacting a cooling drum, as described in JP-A-2004-233604. It is possible to produce a film having favorable optical characteristics such as corners.

  Specifically, 1) When producing a long film by the melt extrusion method, a sheet-like thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less; 2) melting When producing a long film by extrusion, the enclosure member covers from the die opening to the first cooling drum that is in close contact, and the distance from the enclosure member to the die opening or the first contact cooling drum is 100 mm or less. Method: 3) Method of heating the temperature of the atmosphere within 10 mm to a specific temperature from the sheet-like thermoplastic resin extruded from the die opening when producing a long film by the melt extrusion method; A sheet-like thermoplastic resin extruded from a die so as to satisfy the above condition is brought into close contact with a cooling drum under a pressure of 50 kPa or less; 5) a long film by a melt extrusion method A method of blowing a wind having a speed difference of 0.2 m / s or less from the cooling speed of the cooling drum that is first brought into contact with the sheet-like thermoplastic resin extruded from the die opening during the production; .

  The long film containing the above olefin polymer resin may be a single layer or a laminated film of two or more layers. The laminated film can be obtained by a known method such as a coextrusion molding method, a co-casting molding method, a film lamination method, or a coating method. Of these, the coextrusion molding method and the co-casting molding method are preferable.

(Cellulose ester resin)
A preferable cellulose ester-based resin film contains cellulose acylate satisfying the following formulas (1) and (2) and contains a compound represented by the following general formula (A). Can be mentioned.

Formula (1) 2.0 <= Z1 <3.0
Formula (2) 0.5 <= X
(In formulas (1) and (2), Z1 represents the total acyl substitution degree of cellulose acylate, and X represents the sum of the propionyl substitution degree and butyryl substitution degree of cellulose acylate.)

<Compound of general formula (A)>
Hereinafter, the general formula (A) will be described in detail.

In the general formula (A), L ₁ and L ₂ each independently represent a single bond or a divalent linking group.

Examples of L ₁ and L ₂ include structures represented by the following formulas. (The following R represents a hydrogen atom or a substituent.)

L ₁ and L ₂ are preferably —O—, —COO—, and —OCO—.

R ₁ , R ₂ and R ₃ each independently represent a substituent. Specific examples of the substituent represented by R ₁ , R ₂ and R ₃ include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, Isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.) , Cycloalkenyl groups (2-cyclopenten-1-yl, 2-cyclohexen-1-yl groups, etc.), alkynyl groups (ethynyl group, propargyl group, etc.), aryl groups (phenyl group, p-tolyl group, naphthyl group, etc.) , Heterocyclic groups (2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group, etc.), cyano group, hydro Xyl group, nitro group, carboxyl group, alkoxy group (methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, etc.), aryloxy group (phenoxy group, 2- Methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), acyloxy group (formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group) , P-methoxyphenylcarbonyloxy group, etc.), amino group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group etc.), acylamino group (formylamino group, acetylamino) Group, pivaloylamino group, Uroylamino group, benzoylamino group, etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group) Etc.), mercapto group, alkylthio group (methylthio group, ethylthio group, n-hexadecylthio group etc.), arylthio group (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group etc.), sulfamoyl group (N-ethylsulfuryl group) Famoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′phenylcarbamoyl) Sulfa Yl group, etc.), sulfo group, acyl group (acetyl group, pivaloylbenzoyl group, etc.), carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-) Octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group and the like.

R ₁ and R ₂ are preferably a substituted or unsubstituted phenyl group or a substituted or unsubstituted cyclohexyl group. More preferred are a phenyl group having a substituent and a cyclohexyl group having a substituent, and further preferred are a phenyl group having a substituent at the 4-position and a cyclohexyl group having a substituent at the 4-position.

R ₃ is preferably a hydrogen atom, halogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, cyano group, amino group, More preferably, they are a hydrogen atom, a halogen atom, an alkyl group, a cyano group, and an alkoxy group.

Wa and Wb represent a hydrogen atom or a substituent,
(I) Wa and Wb may be bonded to each other to form a ring, (II) at least one of Wa and Wb may have a ring structure, or (III) at least one of Wa and Wb is alkenyl It may be a group or an alkynyl group.

  Specific examples of the substituent represented by Wa and Wb include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert- Butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.), cycloalkenyl group ( 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group etc.), alkynyl group (ethynyl group, propargyl group etc.), aryl group (phenyl group, p-tolyl group, naphthyl group etc.), heterocyclic group ( 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group, etc.), cyano group, hydroxyl group Nitro group, carboxyl group, alkoxy group (methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, etc.), aryloxy group (phenoxy group, 2-methylphenoxy group) 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), acyloxy group (formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p- Methoxyphenylcarbonyloxy group, etc.), amino group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group, etc.), acylamino group (formylamino group, acetylamino group, pivaloylamino) Group, Lauroy Amino group, benzoylamino group, etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group) Etc.), mercapto group, alkylthio group (methylthio group, ethylthio group, n-hexadecylthio group etc.), arylthio group (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group etc.), sulfamoyl group (N-ethylsulfuryl group) Famoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′phenylcarbamoyl) Sulfamoyl group Etc.), sulfo group, acyl group (acetyl group, pivaloylbenzoyl group, etc.), carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl) Group, N- (methylsulfonyl) carbamoyl group, etc.).

  The above substituents may be further substituted with the above groups.

  (1) When Wa and Wb are bonded to each other to form a ring, the following structures are exemplified.

  When Wa and Wb are bonded to each other to form a ring, it is preferably a nitrogen-containing 5-membered ring or a sulfur-containing 5-membered ring, particularly preferably represented by the following general formula (1) or general formula (2). It is a compound.

In the general formula (1), A ₁ and A ₂ each independently represent —O—, —S—, —NRx— (Rx represents a hydrogen atom or a substituent) or —CO—. The example of the substituent represented by Rx is synonymous with the specific example of the substituent represented by said Wa and Wb. Rx is preferably a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group.

  In the general formula (1), X represents a nonmetallic atom belonging to Groups 14-16.

  X is preferably ═O, ═S, ═NRc, ═C (Rd) Re. Here, Rc, Rd, and Re represent substituents, and examples thereof are synonymous with specific examples of the substituents represented by Wa and Wb.

_{L 1, L 2, R 1} , R _{2, R} 3, n is _{L 1, L 2, R 1} , same meanings as R _{2, R} 3, n in the general formula (A).

In the general formula (2), _{Q 1} is -O -, - S -, - NRy- (Ry represents a hydrogen atom or a substituent), - CRaRb- (Ra and Rb represents a hydrogen atom or a substituent), or -CO- is represented. Here, Ry, Ra, and Rb represent substituents, and examples are synonymous with specific examples of the substituents represented by Wa and Wb.

  Y represents a substituent.

  Examples of the substituent represented by Y are the same as the specific examples of the substituent represented by Wa and Wb.

  Y is preferably an aryl group, a heterocyclic group, an alkenyl group, or an alkynyl group.

  Examples of the aryl group represented by Y include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group. A phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable.

  Examples of the heterocyclic group include heterocyclic groups containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group. Group, pyrrolyl group, thienyl group, pyridinyl group and thiazolyl group are preferred.

  These aryl groups or heterocyclic groups may have at least one substituent. Examples of the substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, and 1 to 1 carbon atoms. 6 alkylsulfinyl groups, C 1-6 alkylsulfonyl groups, carboxyl groups, C 1-6 fluoroalkyl groups, C 1-6 alkoxy groups, C 1-6 alkylthio groups, C 1 -6 N-alkylamino group, C2-C12 N, N-dialkylamino group, C1-C6 N-alkylsulfamoyl group, C2-C12 N, N-dialkylsulfa Examples include a moyl group.

_{L 1, L 2, R 1} , R _{2, R} 3, n is _{L 1, L 2, R 1} , same meanings as R _{2, R} 3, n in the general formula (A).

  (2) In the general formula (A), a specific example when at least one of Wa and Wb has a ring structure is preferably the following general formula (3).

In the general formula (3), Q ₃ represents ═N— or ═CRz— (Rz represents a hydrogen atom or a substituent), and Q ₄ represents a nonmetallic atom belonging to Groups 14-16. Z represents a nonmetallic atom group that forms a ring with Q ₃ and Q ₄ .

The ring formed from Q ₃ , Q ₄ and Z may be condensed with another ring.

The ring formed from Q ₃ , Q ₄ and Z is preferably a nitrogen-containing 5-membered ring or 6-membered ring condensed with a benzene ring.

_{L 1, L 2, R 1} , R _{2, R} 3, n is _{L 1, L 2, R 1} , same meanings as R _{2, R} 3, n in the general formula (A).

  (3) When at least one of Wa and Wb is an alkenyl group or an alkynyl group, a vinyl group having a substituent or an ethynyl group is preferable.

  Of the compounds represented by the general formula (1), general formula (2) and general formula (3), the compound represented by the general formula (3) is particularly preferable.

  The compound represented by the general formula (3) is superior in heat resistance and light resistance to the compound represented by the general formula (1), and is an organic solvent compared to the compound represented by the general formula (2). The solubility with respect to and the compatibility with a polymer are favorable.

  The compound represented by the general formula (A) according to the present invention can be contained by appropriately adjusting the amount for imparting desired wavelength dispersibility and anti-bleeding property. The content is preferably 1 to 15% by mass, and particularly preferably 2 to 10% by mass. If it is in this range, sufficient wavelength dispersibility and anti-bleeding property can be imparted to the cellulose derivative of the present invention.

  In addition, the compound represented by General formula (A), General formula (1), General formula (2), and General formula (3) can be performed with reference to a known method. Specifically, it can be synthesized with reference to Journal of Chemical Crystallography (1997); 27 (9); 512-526, JP 2010-31223 A, JP 2008-107767 A, and the like.

<Cellulose acylate>
The cellulose acylate film used in the production method of the present invention contains cellulose acylate as a main component.

  The cellulose acylate film preferably contains cellulose acylate in a range of 60 to 100% by mass with respect to 100% by mass of the total mass of the film. Further, the total acyl group substitution degree of cellulose acylate is 2.0 or more and less than 3.0, and more preferably 2.2 to 2.7.

  Examples of the cellulose acylate include esters of cellulose and an aliphatic carboxylic acid and / or aromatic carboxylic acid having about 2 to 22 carbon atoms, and in particular, an ester of cellulose and a lower fatty acid having 6 or less carbon atoms. Preferably there is.

  The acyl group bonded to the hydroxyl group of cellulose may be linear or branched, and may form a ring. Furthermore, another substituent may be substituted. In the case of the same substitution degree, birefringence decreases when the number of carbon atoms described above is large. Therefore, the number of carbon atoms is preferably selected from acyl groups having 2 to 6 carbon atoms, and the propionyl substitution degree and the butyryl substitution degree. Is a sum of 0.5 or more. The cellulose acylate preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.

  Specifically, cellulose acylate includes propionate group, butyrate group or phthalyl group in addition to acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate or cellulose acetate phthalate. Bound cellulose mixed fatty acid esters can be used. The butyryl group forming butyrate may be linear or branched.

  In the present invention, cellulose acetate, cellulose acetate butyrate, or cellulose acetate propionate is particularly preferably used as the cellulose acylate.

  Moreover, the cellulose acylate according to the present invention preferably satisfies the following mathematical formulas (i) and (ii).

Formula (i) 2.0 ≦ X + Y <3.0
Formula (ii) 0.5 ≦ X
In the formula, Y represents the degree of substitution of the acetyl group, and X represents the degree of substitution of the propionyl group or butyryl group or a mixture thereof.

  Further, in order to obtain optical characteristics that meet the purpose, resins having different degrees of substitution may be mixed and used. In this case, the mixing ratio is preferably 1:99 to 99: 1 (mass ratio).

  Among those mentioned above, cellulose acetate propionate is particularly preferably used as the cellulose acylate. In cellulose acetate propionate, 0 ≦ Y ≦ 2.5 and 0.5 ≦ X ≦ 3.0 (where 2.0 ≦ X + Y <3.0) are preferable, and 0 More preferably, 0.5 ≦ Y ≦ 2.0 and 1.0 ≦ X ≦ 2.0 (where 2.0 ≦ X + Y <3.0). In addition, the substitution degree of an acyl group can be measured according to ASTM-D817-96.

  The number average molecular weight of the cellulose acylate is preferably in the range of 60,000 to 300,000 because the mechanical strength of the resulting film becomes strong. More preferably, cellulose acylate having a number average molecular weight of 70,000 to 200,000 is used.

  The weight average molecular weight (Mw) and number average molecular weight (Mn) of cellulose acylate are measured using gel permeation chromatography (GPC). The measurement conditions are as follows. In addition, this measuring method can be used also as a measuring method of the other polymer in this invention.

Solvent: methylene chloride;
Column: Three Shodex K806, K805, K803G (made by Showa Denko KK) are connected and used;
Column temperature: 25 ° C .;
Sample concentration: 0.1% by mass;
Detector: RI Model 504 (manufactured by GL Sciences);
Pump: L6000 (manufactured by Hitachi, Ltd.);
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 100000 to 500 samples are used. Thirteen samples are used at approximately equal intervals.

  The residual sulfuric acid content in the cellulose acylate is preferably in the range of 0.1 to 45 mass ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. If the residual sulfuric acid content exceeds 45 ppm by mass, there is a tendency to break during hot stretching or slitting after hot stretching. The residual sulfuric acid content is more preferably in the range of 1 to 30 mass ppm. The residual sulfuric acid content can be measured by the method prescribed in ASTM D817-96.

  Moreover, it is preferable that the free acid content in a cellulose acylate is 1-500 mass ppm. The above range is preferable because it is difficult to break as described above. In addition, it is preferable that free acid content is the range of 1-100 mass ppm, and also it becomes difficult to fracture | rupture. The range of 1-70 mass ppm is especially preferable. The free acid content can be measured by the method prescribed in ASTM D817-96.

  By washing the synthesized cellulose acylate more sufficiently than when used in the solution casting method, the residual alkaline earth metal content, residual sulfuric acid content, and residual acid content are within the above ranges. And can be preferable.

Moreover, it is preferable that a cellulose acylate has few bright spot foreign materials when it is made into a film. Bright spot foreign matter means that when two polarizing plates are placed in a crossed Nicol state, an optical film or the like is placed between them, light is applied from one polarizing plate side, and observation is performed from the other polarizing plate side. It means a point (foreign matter) where light from the opposite side appears to leak. The number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less, more preferably 100 / cm ² or less, and 50 / cm ² or less. Is more preferably 30 pieces / cm ² or less, particularly preferably 10 pieces / cm ² or less, and most preferably none.

Further, the bright spots having a diameter of 0.005 to 0.01 mm or less are also preferably 200 pieces / cm ² or less, more preferably 100 pieces / cm ² or less, and 50 pieces / cm ² or less. Is more preferably 30 pieces / cm ² or less, particularly preferably 10 pieces / cm ² or less, and most preferably none.

  The cellulose as a raw material for cellulose acylate is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose acylate obtained from them can be mixed and used at an arbitrary ratio.

  Cellulose acylate can be produced by a known method. Specifically, for example, it can be synthesized with reference to the method described in JP-A-10-45804.

  Cellulose acylate is also affected by trace metal components in cellulose acylate. These trace metal components are thought to be related to the water used in the production process, but it is preferable that there are few components that can become insoluble nuclei, in particular, metal ions such as iron, calcium, magnesium, An insoluble matter may be formed by salt formation with a polymer degradation product or the like that may contain an organic acidic group, and it is preferable that the amount is small. In addition, the calcium (Ca) component easily forms a coordination compound (that is, a complex) with an acidic component such as a carboxylic acid or a sulfonic acid, and many ligands. Insoluble starch, turbidity) may be formed.

  Specifically, for the iron (Fe) component, the content in cellulose acylate is preferably 1 mass ppm or less. Moreover, about calcium (Ca) component, content in a cellulose acylate becomes like this. Preferably it is 60 mass ppm or less, More preferably, it is 0-30 mass ppm. Furthermore, regarding the magnesium (Mg) component, too much is also insoluble, so the content in the cellulose acylate is preferably 0 to 70 ppm by mass, and particularly preferably 0 to 20 ppm by mass. .

  It should be noted that the content of metal components such as the content of iron (Fe) component, the content of calcium (Ca) component, the content of magnesium (Mg) component, etc., is a micro digest wet cracking device ( After pretreatment with sulfuric acid decomposition (sulfuric acid decomposition) and alkali fusion, analysis can be performed using ICP-AES (inductively coupled plasma emission spectrometer).

<Additive>
The long stretched film obtained by the production method according to the embodiment of the present invention may be obtained by appropriately mixing polymer components other than the cellulose ester described later. The polymer component to be mixed is preferably one having excellent compatibility with the cellulose ester, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and further preferably 92% or more.

  Additives added to the dope include plasticizers, ultraviolet absorbers, retardation modifiers, antioxidants, deterioration inhibitors, peeling aids, surfactants, dyes, fine particles, and the like. In the present embodiment, additives other than the fine particles may be added during the preparation of the cellulose ester solution, or may be added during the preparation of the fine particle dispersion. It is preferable to add a plasticizer, an antioxidant, an ultraviolet absorber, or the like that imparts heat and moisture resistance to the polarizing plate used in the liquid crystal image display device.

  It is preferable that these compounds are contained so that it may become 1-30 mass% with respect to a cellulose ester, Preferably it is 1-20 mass%. In order to suppress bleeding out during stretching and drying, a compound having a vapor pressure at 200 ° C. of 1400 Pa or less is preferable.

  These compounds may be added together with the cellulose ester or the solvent during the preparation of the cellulose ester solution, or may be added during or after the solution preparation.

<Retardation adjuster>
The compound added to adjust the retardation of the cellulose ester resin film used in the production method of the present invention has two or more aromatic rings as described in the specification of European Patent 911,656A2. Aromatic compounds can be used.

  Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. Particularly preferred is an aromatic heterocycle, and the aromatic heterocycle is generally an unsaturated heterocycle. Of these, a 1,3,5-triazine ring is particularly preferred.

<Polymer or oligomer>
The cellulose ester resin film used in the production method of the present invention has a cellulose ester and a substituent selected from a carboxyl group, a hydroxyl group, an amino group, an amide group, and a sulfonic acid group and has a weight average molecular weight of 500 to 500. It is preferable to contain a polymer or oligomer of a vinyl compound in the range of 200,000. The mass ratio of the content of the cellulose ester and the polymer or oligomer is preferably in the range of 95: 5 to 50:50.

<Matting agent>
The cellulose ester-based resin film used in the production method of the present invention can contain fine particles as a matting agent in a stretched film, thereby facilitating transportation and winding when the stretched film is a long film. be able to.

  The particle size of the matting agent is preferably primary particles or secondary particles of 10 nm to 0.1 μm. A substantially spherical matting agent having a primary particle acicular ratio of 1.1 or less is preferably used.

  As the fine particles, those containing silicon are preferable, and silicon dioxide is particularly preferable. As fine particles of silicon dioxide preferable for this embodiment, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) manufactured by Nippon Aerosil Co., Ltd. And commercially available products such as Aerosil 200V, R972, R972V, R974, R202, and R812 can be preferably used. Examples of polymer fine particles include silicone resin, fluorine resin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. Examples include Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.). Can do.

  The fine particles of silicon dioxide preferably have a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / L or more. The average diameter of the primary particles is more preferably 5 to 16 nm, further preferably 5 to 12 nm. A smaller primary particle average diameter is preferred because haze is low. The apparent specific gravity is preferably 90 to 200 g / L or more, and more preferably 100 to 200 g / L or more. Higher apparent specific gravity makes it possible to produce a high-concentration fine particle dispersion, which is preferable because no haze or aggregates are generated.

The addition amount of the matting agent in the present embodiment is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and still more preferably 0.08 to 0.16 g per 1 m ^{2 of the} long stretched film.

<Other additives>
In addition, heat stabilizers such as inorganic fine particles such as kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, and alumina, and alkaline earth metal salts such as calcium and magnesium may be added. Further, a surfactant, a peeling accelerator, an antistatic agent, a flame retardant, a lubricant, an oil agent and the like may be added.

(Film forming method of cellulose ester resin)
The cellulose ester resin film used in the production method of the present invention may be formed by either a solution casting method or a melt casting method.

  The solution casting method and the melt casting method will be described below.

<Solution casting method>
In the solution casting method, a dope is prepared by dissolving a resin and an additive in an organic solvent, the dope is cast on a belt-shaped or drum-shaped metal support, and the cast dope is dried as a web. It is performed by a step, a step of peeling from a metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.

  The solution casting method is preferably used because it is excellent in suppressing coloration of the film, suppressing foreign matter defects, suppressing optical defects such as die lines, flatness of the film, and transparency.

  The concentration of cellulose acetate in the dope is preferably higher because the drying load after casting on a metal support can be reduced. However, if the concentration of cellulose acetate is too high, the load during filtration increases and the filtration accuracy increases. Becomes worse. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%. The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

  The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. Higher temperatures are preferable because the web can be dried faster, but if the temperature is too high, the web may foam or flatness may deteriorate.

  The preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the cellulose ester-based resin film to exhibit good planarity, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130. It is mass%, Most preferably, it is 20-30 mass% or 70-120 mass%.

  The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  In the drying step of the cellulose resin film, the web is peeled off from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less. Particularly preferably, it is 0 to 0.01% by mass or less.

  In the film drying step, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

  The organic solvent useful for forming the dope when the cellulose ester resin film according to the present invention is produced by the solution casting method is used without limitation as long as it dissolves cellulose acetate and other additives at the same time. Can do.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels and becomes easy to peel off from the metal support. When the proportion of alcohol is small, the role of promoting cellulose acetate dissolution in non-chlorine organic solvent systems There is also.

  In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, at least 15 to 45 mass in total of at least three kinds of acrylic resin, cellulose ester resin, and acrylic particles are used. It is preferable that the dope composition is dissolved in%.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

<Melt casting method>
The melt film forming method is a preferable film forming method from the viewpoints that it is easy to reduce the retardation Rt in the thickness direction after oblique stretching, the amount of residual volatile components is small, and the dimensional stability of the film is excellent. The melt film-forming method refers to heating and melting a composition containing an additive such as a resin and a plasticizer to a temperature exhibiting fluidity, and then casting a melt containing fluid cellulose acetate. Methods formed by melt casting can be classified into melt extrusion molding methods, press molding methods, inflation methods, injection molding methods, blow molding methods, stretch molding methods, and the like. Among these, the melt extrusion method is preferable, in which a film having excellent mechanical strength and surface accuracy can be obtained.

  It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

  Pelletization may be performed by a known method. For example, dry cellulose acetate, a plasticizer, and other additives are fed to an extruder with a feeder and kneaded using a single-screw or twin-screw extruder, and formed into a strand form from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

  A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

  The extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (decrease in molecular weight, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

  A film is formed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

  Using a single or twin screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C., filtered through a leaf disk filter, etc. to remove foreign matter, and then formed into a film from a T die. The film is nipped by a cooling roll and an elastic touch roll, and solidified on the cooling roll.

  When introducing from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

  The extrusion flow rate is preferably performed stably by introducing a gear pump or the like. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances. The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

  Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

  The film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.

  The elastic touch roll is also called a pinching rotator. As the elastic touch roll, a commercially available one can be used.

  When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

  The long film containing the above cellulose ester resin may be a single layer or a laminated film of two or more layers. The laminated film can be obtained by a known method such as a coextrusion molding method, a co-casting molding method, a film lamination method, or a coating method. Of these, the coextrusion molding method and the co-casting molding method are preferable.

<Long stretched film>
The elongate stretched film which concerns on this invention is manufactured by the said manufacturing method.

  Hereinafter, the long film containing a thermoplastic resin will be described.

  The film thickness of the long film before oblique stretching is preferably 30 to 300 μm, more preferably 40 to 150 μm.

  In the present invention, the thickness unevenness σm in the flow direction of the long film supplied to the oblique stretching apparatus keeps the film take-up tension at the entrance of the oblique stretching tenter, which will be described later, and stabilizes the optical characteristics such as the orientation angle and retardation. From the viewpoint, it is necessary to be less than 0.30 μm, preferably less than 0.25 μm, more preferably less than 0.20 μm. When the thickness unevenness σm in the flow direction of the long film before oblique stretching is 0.30 μm or more, variations in optical properties such as retardation and orientation angle of the long stretched film are remarkably deteriorated. Here, σm is a value represented by an average value of the standard deviation σ in the flow direction at each width position.

  Moreover, a film having a thickness gradient in the width direction may be supplied as the long film before oblique stretching. The gradient of the thickness of the long film before the oblique stretching is to stretch a film with various thickness gradients experimentally changed so that the film thickness at the position where stretching in the subsequent process is completed can be made the most uniform. This can be determined empirically. The gradient of the thickness of the long film before oblique stretching can be adjusted, for example, so that the thickness of the end on the thick side is about 0.5 to 3% thicker than the end on the thin side. it can.

  The width of the long film after oblique stretching is not particularly limited, but may be 500 to 3000 mm, preferably 1000 to 2000 mm.

  The preferable elastic modulus at the stretching temperature at the time of oblique stretching of the long film is 0.01 Mpa or more and 5000 Mpa or less, more preferably 0.1 Mpa or more and 500 Mpa or less, expressed as Young's modulus. If the elastic modulus is too low, the shrinkage rate during stretching and after stretching will be low, and wrinkles will be difficult to disappear.If it is too high, the tension applied during stretching will increase, and the strength of the part holding both side edges of the film will be increased. It is necessary to increase the load, and the load on the tenter in the subsequent process increases.

  As the long film before oblique stretching, a non-oriented film may be used, or a film having an orientation in advance may be supplied. Further, if necessary, the width distribution of the orientation of the long film before oblique stretching may be a bow shape, so-called bowing. In short, the orientation state of the long film before oblique stretching can be adjusted so that the orientation of the film at the position where stretching in the subsequent step is completed can be made desirable.

  Further, the long stretched film of the present invention has an orientation angle θ that is inclined in a range of greater than 0 ° and less than 90 °, preferably in a range of 30 ° or more and 60 ° or less, with respect to the winding direction. It is preferable to incline in the range of 40 ° or more and 50 ° or less. Moreover, the variation of the orientation angle θ of the long stretched film according to the present invention is preferably less than 0.6 °, and more preferably less than 0.4 °. A long stretched film with a variation in orientation angle θ of less than 0.6 ° is bonded to a polarizer to obtain a circularly polarizing plate, and when this is installed in an image display device such as an organic electroluminescence display device, the display quality is improved. It becomes possible to make the uniformity good.

  Moreover, it is preferable that the retardation value Ro (550) measured at wavelength 550nm of the elongate stretched film of this invention exists in the range of 120 nm or more and 160 nm or less, More preferably, it is the range of 130 nm or more and 150 nm or less. Moreover, the variation of the in-plane retardation Ro of the long stretched film according to the present invention is 4 nm or less, preferably 3 nm or less. By setting the variation of the in-plane retardation Ro within the above range, it is possible to improve the uniformity of display quality when used as a film for an organic electroluminescence display device.

  The in-plane retardation Ro of the long stretched film according to the present invention is selected to be an optimum value depending on the design of the display device used. Note that Ro is a value obtained by multiplying the difference between the refractive index nx in the in-plane slow axis direction and the refractive index ny in the direction perpendicular to the slow axis by the average thickness d of the film (Ro = (nx −ny) × d).

  The average thickness of the long stretched film according to the present invention is preferably 5 to 100 μm, more preferably 10 to 80 μm from the viewpoint of mechanical strength, etc., but the slit is caused by the inclination of the orientation angle on the inner peripheral side. The problem of scratches and dents at the time becomes prominent when producing a thin long stretched film from the viewpoint of mechanical strength. Therefore, the production method of the present invention is particularly preferably used when producing a thin film in which the average thickness of the long stretched film is in the range of 10 to 35 μm.

  Moreover, since the thickness unevenness in the width direction affects the availability of winding, it is preferably 3 μm or less, more preferably 2 μm or less.

<Circularly polarizing plate>
The circularly polarizing plate when the long stretched film according to this embodiment is used will be described.

  In the circularly polarizing plate, a polarizing plate protective film, a polarizer, a λ / 4 retardation film, and an adhesive layer are laminated in this order, and the slow axis of the λ / 4 retardation film and the absorption axis of the polarizer Is an angle of 45 °.

  A long polarizing plate protective film, a long polarizer, and a long λ / 4 retardation film (stretched film) using the long stretched film according to this embodiment are laminated in this order. It is preferable.

  The circularly polarizing plate using the long stretched film according to the present embodiment uses a stretched polyvinyl alcohol doped with iodine or a dichroic dye as a polarizer, and is a λ / 4 retardation film / polarizer. It can be manufactured by pasting in a configuration.

  The film thickness of the circularly polarizing plate is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

  The circularly polarizing plate can be produced by a general method. The λ / 4 retardation film subjected to the alkali saponification treatment is preferably bonded to one surface of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution.

  The circularly polarizing plate can be configured by further bonding a release film on the opposite surface of the polarizing plate protective film of the polarizing plate. The protective film and the release film are used for the purpose of protecting the polarizing plate at the time of shipment of the polarizing plate, product inspection, and the like.

<Display device>
By incorporating a circularly polarizing plate produced using the long stretched film according to the present embodiment into a display device, various display devices with excellent visibility can be produced. The display device is preferably an organic EL display.

  Although an example of a structure of the said organic EL image display apparatus is shown in FIG. 6, as an organic EL image display apparatus in the case of using the elongate stretched film which concerns on this embodiment, it is not limited to this.

  A polarizer is formed on an organic electroluminescence element having a metal electrode 102, a light emitting layer 103, a transmissive electrode (ITO) 104, and a sealing layer 105 in this order on a substrate 101 made of glass, polyimide, or the like via an adhesive tank 106. An organic electroluminescence image display device is configured by providing a circularly polarizing plate in which 108 is sandwiched between a λ / 4 retardation film 107 and a protective film 109. The protective film 108 is preferably laminated with a cured layer. The cured layer not only prevents scratches on the surface of the organic electroluminescence image display device but also has an effect of preventing warpage due to the circularly polarizing plate. Further, an antireflection layer may be provided on the cured layer. The thickness of the organic electroluminescence element itself is about 1 μm.

  Generally, in an organic electroluminescence image display device, a metal electrode, a light emitting layer, and a transparent electrode are sequentially laminated on a transparent substrate to form an element (organic electroluminescence element) that is a light emitter. Here, the light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or Structures with various combinations, such as a laminate of such a light-emitting layer and an electron injection layer composed of a perylene derivative, and / or a laminate of these hole injection layer, light-emitting layer, and electron injection layer, are known. ing.

  In an organic electroluminescence image display device, holes and electrons are injected into the light emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by the recombination of these holes and electrons is reduced by the fluorescent material. It emits light on the principle that it is excited and emits light when the excited fluorescent material returns to the ground state. The mechanism of recombination on the way is the same as that of a general diode, and as can be expected from this, the current and the light emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic electroluminescence image display device, in order to extract light emitted from the light emitting layer, at least one of the electrodes must be transparent, and usually a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is used. Used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic electroluminescence image display device having such a configuration, the light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the light emitting layer transmits light almost completely like the transparent electrode. As a result, the light that is incident from the surface of the transparent substrate when not emitting light, passes through the transparent electrode and the light emitting layer, and is reflected by the metal electrode again exits to the surface side of the transparent substrate. The display surface of the electroluminescence image display device looks like a mirror surface.

  The circularly polarizing plate for an organic electroluminescence display device using the long stretched film according to this embodiment is suitable for a display device for organic electroluminescence in which such external light reflection is particularly problematic.

  The present specification discloses various aspects of the technology as described above, and the main technologies are summarized below.

  The manufacturing method of the elongate stretched film which concerns on 1 aspect of this invention is the process of forming the elongate film containing a thermoplastic resin, the specific direction different from the winding direction of the film after extending | stretching the said elongate film. The both ends of the long film in the width direction are gripped by a gripping tool of an obliquely stretched tenter and conveyed while the long film is moved in a direction greater than 0 ° and less than 90 ° with respect to the width direction. In the manufacturing method having at least a step of obliquely stretching, a slit step of cutting both ends of the long stretched film after the oblique stretching step with a slit device, and a step of winding the long stretched film after the slit step, In the slit process, the cutting is performed so that the cutting width on the inner peripheral side of the end portion of the long stretched film is larger than the cutting width on the outer peripheral side.

  According to such a configuration, it is possible to reduce film pieces and debris that adhere to the film when slitting both ends of the long stretched film by oblique stretch film formation, to prevent flaws from sticking to the film surface, and to suppress the risk of production stoppage It becomes.

  Moreover, in the manufacturing method of the elongate stretched film of this invention, it is suitable to cut | disconnect the inner peripheral side of a elongate stretched film on the conditions of temperature higher than an outer peripheral side in the said slit process.

  According to such a configuration, the effect of the present invention can be further enhanced.

  Moreover, in the manufacturing method of the elongate stretched film of this invention, it is suitable that adjustment of the said temperature is performed by heating with a heat generator before a cutting | disconnection, or adjusting the elapsed time from a diagonal stretch process. is there.

  According to such a structure, the temperature adjustment at the time of a slit process can be performed more simply.

  Moreover, in the manufacturing method of the elongate stretched film of this invention, it is suitable for the said slit apparatus to have a mechanism which follows according to the change of the turning angle of the said elongate stretched film.

  According to such a configuration, it is not necessary to remove or reconstruct the slit device when changing the inclination angle of the winding direction with respect to the feeding direction, resulting in excellent productivity.

  Moreover, in the manufacturing method of the elongate stretched film of this invention, it is suitable for the said slit apparatus to have a mechanism which can confirm the angle of the conveyance direction of the said elongate stretched film, and the advancing direction of a slit blade.

  According to such a structure, a slit apparatus can operate | move more simply and accurately with the movement of a feeding apparatus and a winding apparatus.

  Moreover, in the manufacturing method of the elongate stretched film of this invention, it is suitable in the said diagonal stretch process that the travel speed of the holding tool which travels on the left-right asymmetric rail of the said diagonal stretch tenter is 25-150 m / min. is there.

  According to such a configuration, the effects of the present invention can be further improved.

  The long stretched film which concerns on 1 aspect of this invention is manufactured by the said manufacturing method, and a film thickness is 10-35 micrometers, It is characterized by the above-mentioned.

  According to such a structure, even if it is a thin elongate stretched film, the film without the crack at the time of a slit and a dent can be obtained.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

[Long stretched film 1]
(Manufacture of cycloolefin film)
In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane, 1.2 parts of 1-hexene, 0.15 part of dibutyl ether, and 0.30 part of triisobutylaluminum were mixed in a reactor at room temperature, and then kept at 45 ° C. 20 parts of tricyclo [4.3.0.12,5] deca-3,7-diene (dicyclopentadiene, hereinafter abbreviated as DCP), 1,4-methano-1,4,4a, 9a-tetrahydrofluorene ( Hereinafter, a norbornene-based monomer comprising 140 parts of MTF) and 40 parts of 8-methyl-tetracyclo [4.4.0.12, 5.17,10] -dodec-3-ene (hereinafter abbreviated as MTD). The mixture and 40 parts of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours for polymerization. To the polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to deactivate the polymerization catalyst and stop the polymerization reaction.

  Next, 270 parts of cyclohexane is added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and further 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst. The mixture was heated to 200 ° C. while being pressurized and stirred, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP / MTF / MTD ring-opening polymer hydrogenated polymer. After removing the hydrogenation catalyst by filtration, a soft polymer (manufactured by Kuraray; Septon 2002) and an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) are added and dissolved in the resulting solution. (Both 0.1 parts per 100 parts polymer).

  Next, cyclohexane and other volatile components, which are solvents, are removed from the solution using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), the hydrogenated polymer is extruded in a strand form from an extruder in a molten state, and pellets after cooling. And recovered. When the copolymerization ratio of each norbornene monomer in the polymer was calculated from the composition of residual norbornenes in the solution after polymerization (by gas chromatography method), it was almost charged at DCP / MTF / MTD = 10/70/20. It was equal to the composition. This hydrogenated ring-opened polymer had a weight average molecular weight (Mw) of 31,000, a molecular weight distribution (Mw / Mn) of 2.5, a hydrogenation rate of 99.9%, and a Tg of 134 ° C. The obtained pellets of the ring-opened polymer hydrogenated product were dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove moisture.

  Next, the pellets were melt extruded using a short shaft extruder having a coat hanger type T die (Mitsubishi Heavy Industries, Ltd .: screw diameter 90 mm, T die lip material is tungsten carbide, peel strength 44N from molten resin). A cycloolefin polymer film having a thickness of 100 μm was produced by molding. In extrusion molding, a long film original fabric A having a width of 900 mm was obtained in molding conditions of a molten resin temperature of 240 ° C. and a T die temperature of 240 ° C. in a clean room of class 10,000 or less. The long film original fabric A was wound up on a roll.

(Oblique stretching process)
The long film original fabric A of norbornene-based resin obtained above was stretched by the method shown below using the oblique stretching apparatus according to the present invention to obtain a stretched film.

  First, the angle (swivel angle) formed by the film feeding direction and the winding direction was set to 47 °. And the both ends of the elongate film A sent from a film delivery apparatus were hold | gripped with the 1st clip (the inner peripheral side of a rail) and the 2nd clip (the outer peripheral side of a rail).

  In addition, when gripping a long film, the long film is gripped by moving the clip levers of the first and second clips with a clip closer. When gripping a clip, both ends of the long film are simultaneously gripped by the first and second clips at the same time, and the line drawing connecting the gripping positions at both ends is parallel to the axis parallel to the lateral direction of the film. Grip like so.

  Next, the gripped unstretched film was heated by passing the preheating zone, the stretching zone, and the heat setting zone in the heating zone with the first and second clips, and stretched in the width direction to obtain a stretched film. . In addition, the film conveyance speed at the time of a heating and extending | stretching was 5 m / min, and the extending | stretching temperature was 141 degreeC.

  Moreover, the stretch ratio of the film before and after stretching was doubled so that the film after stretching had a thickness of 50 μm and a width of 1800 mm.

  The long stretched film of cycloolefin obtained by the above steps was designated as stretched film 1.

[Long stretched film 2-4]
In the stretched films 2 to 4, the film thickness of the film as shown in Table 1 below, the width of the film thickness, the orientation angle after stretching, the film thickness after stretching, the transport speed, the stretching temperature, and the turning angle are changed. A long stretched film of each cycloolefin was prepared in the same manner as in Production Example 1 except that was obliquely stretched.

  Table 1 below describes the stretching conditions for each long stretched film. The stretching conditions are as follows.

Orientation angle after stretching (°): average orientation angle measured at a pitch of 50 mm in the film width direction.
Film thickness after stretching (μm): Average film thickness measured at 20 mm pitch in the film width direction.
Conveying speed (m / min): Traveling speed of the gripping tool that travels on the left-right asymmetric rail of the obliquely stretched tenter.
Swivel angle (°): Angle formed by the film feeding direction and the film winding direction.
Stretching temperature (° C.): Temperature at which the film is stretched.
Stretch ratio: A value represented by W / W0 when the width of the film before oblique stretching is W0 and the film width after oblique stretching is W.

[Long stretched film 5]
(Manufacture of cellulose ester film)
<< Synthesis of Sugar Ester Compound 1 >>
Four-headed Kolben equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube were charged with 34.2 g (0.1 mol) of sucrose, 180.8 g (0.6 mol) of benzoic anhydride, 379. 7 g (4.8 mol) was charged, the temperature was raised while bubbling nitrogen gas from a nitrogen gas introduction tube with stirring, and an esterification reaction was carried out at 70 ° C. for 5 hours. Next, the inside of the Kolben was depressurized to 4 × 10 ² Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 × 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off. Finally, 100 g of water was added to the collected toluene layer, and after washing with water at room temperature for 30 minutes, the toluene layer was collected, and toluene was distilled off at 60 ° C. under reduced pressure (4 × 10 ² Pa or less). A mixture of compounds A-1, A-2, A-3, A-4 and A-5 as shown in 7 was obtained.

  When the obtained mixture was analyzed by HPLC and LC-MASS, A-1 was 1.3% by mass, A-2 was 13.4% by mass, A-3 was 13.1% by mass, and A-4 was 31%. 0.7% by mass and A-5 was 40.5% by mass. The average degree of substitution was 5.5.

  Moreover, the measurement conditions of the said HPLC-MASS are as follows.

1) LC section Device: JASCO CO., LTD. Column oven (JASCO CO-965), detector (JASCO UV-970-240 nm), pump (JASCO PU-980), degasser (JASCO DG-980-50)
Column: Inertsil ODS-3 Particle size 5 μm 4.6 × 250 mm (manufactured by GL Sciences Inc.)
Column temperature: 40 ° C
Flow rate: 1 ml / min
Mobile phase: THF (1% acetic acid): H ₂ O (50:50)
Injection volume: 3 μl
2) MS unit Device: LCQ DECA (manufactured by Thermo Quest Co., Ltd.)
Ionization method: Electrospray ionization (ESI) method Spray Voltage: 5 kV
Capillary temperature: 180 ° C
Vaporizer temperature: 450 ° C

<< Synthesis of Ester Compound 1 >>
251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with a thermometer, stirrer, and slow cooling tube The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. The ester compound 1 was obtained by making it dehydrate-condense for 15 hours, and depressurizingly distilling unreacted 1, 2- propylene glycol at 200 degreeC after completion | finish of reaction. The ester compound 1 has an ester of benzoic acid at the end of a polyester chain formed by condensation of 1,2-propylene glycol, phthalic anhydride and adipic acid. The ester compound 1 had an acid value of 0.10 and a number average molecular weight of 450.

<< Preparation of fine particle additive liquid 1 >>
After 11 parts by mass of fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) and 89 parts by mass of ethanol were stirred and mixed with a dissolver for 50 minutes, dispersion was performed with Manton Gorin to prepare a fine particle dispersion 1.

  Subsequently, 1 part by mass of the fine particle dispersion 1 was slowly added while sufficiently stirring the dissolution tank containing 99 parts by mass of methylene chloride. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

<Adjustment of main dope>
Methylene chloride, ethanol, cellulose acetate propionate, compound (C) represented by the following chemical formula 6, sugar ester compound 1, ester compound 1 and fine particle additive solution 1 are sealed in a sealed container so that the composition described below is obtained. And dissolved with stirring to prepare a dope solution.

Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate propionate (acetyl group substitution degree 1.39, propionyl group substitution degree 0.50, total substitution degree 1.89)
100 parts by mass Compound (C) 5.0 parts by mass Sugar ester compound 1 5.0 parts by mass Ester compound 1 2.5 parts by mass Particulate additive liquid 1 1 part by mass

  Subsequently, the dope solution was uniformly cast on a stainless steel belt support using an endless belt casting apparatus. On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and the film was peeled off from the stainless steel belt support.

  The peeled cellulose ester film was stretched 1.1 times in the width direction by a transverse stretching tenter. The temperature conditions of the transverse stretching tenter oven at that time were adjusted to 160 ° C for the preheating zone, 165 ° C for the stretching zone, 172 ° C for the holding zone, and 110 ° C for the cooling zone.

  Next, the tenter clip traces at both ends of the film are trimmed, the drying temperature is 130 ° C., and drying is finished while the long film is conveyed in the drying zone using a number of rolls. Rolled up as B. As described above, a long film original fabric B having a thickness of 100 μm and a width of 900 mm was obtained.

[Long stretched film 6]
In the long stretched film 6, the stretching temperature of the film as shown in Table 1 above, the film thickness of the original film, the width of the original film, the orientation angle after stretching, the film thickness after stretching, the transport speed, the stretching temperature, and the swirl Each stretched film of cellulose ester was prepared in the same manner as in Production Example 1 except that the film was obliquely stretched at different angles.

[Example 1]
After the long stretched film 1 was formed, the long film 1 was continuously sent to the slitting process, and both ends of the film 1 were slit. The slit device consists of a disk-shaped rotating upper blade and a roll-shaped rotating lower blade. The rotating upper blade is made of super steel, and the diameter of the rotating upper blade is 200 mm. The thickness of the blade at the place was 0.5 mm. On the other hand, the material of the roll-shaped rotary lower blade was a super steel material, and the roll diameter of the rotary lower blade was 100 mm. The inner peripheral cut width was 80 mm, the outer peripheral cut width was 60 mm, and the final film width (effective width) was 1660 mm.

  Moreover, the cutting rate (cutting width / total film width before cutting) of the long stretched film after cutting was 7.8%.

[Examples 2-9, Comparative Examples 1-6]
In Examples 2 to 9 and Comparative Examples 1 to 6, the slit process was performed by changing the types of long stretched films as shown in Tables 2 to 5 below, the cutting width on the inner peripheral side, and the cutting width on the outer peripheral side. Cut each long stretched film in the same manner as in Production Example 1. In Examples 4 and 7, the blower opening was heated with a φ30 mm heat gun so that the temperature was 110 ° C., and the inner peripheral side of the film was cut.

(Evaluation of film residue adhesion)
It was determined according to the following evaluation criteria by visually observing whether or not cut chips were attached to the slit blade after the slit process.

A: No cutting residue is seen on the slit blade.
B: Scraps are slightly attached to the slit blade.
C: A lot of cutting residue is attached to the slit blade.

(Evaluation of smoothness of film edge)
The smoothness of the end of the film was determined according to the following evaluation criteria by touching the cut surface of the end of each elongated stretched film after the slitting step with the naked eye and by hand.

A: The film cross section of the cutting part is smooth.
B: When the film section of the cutting part is traced with a finger, it feels rough.
C: When the film cross section of the cutting part is visually observed, tearing or the like occurs in a very small part of the cutting part.

(Appearance evaluation)
In addition, each long stretched film after the slitting process is unwound, and the stretched film is visually or point-projected in a dark room by a point light source projection method to determine whether the following evaluation criteria are present. went.

A: Under visual observation and point light source projection method, even if the film is moved and held over, it is neither pressed nor scratched.
B: Pressed and visually not seen. In addition, under the projection of a point light source, when the film is moved and viewed, it is slightly pressed and scratches are seen.
C: Pressed and visually not seen. Further, under the point light source projection, the film is slightly pressed and scratched while the film is stationary.
D: It is not visually observed and neither scratched nor seen. Moreover, it is clearly pressed and scratched under the point light source projection.
E: Pressed and scratched under visual and point light source projection.

  The said evaluation result is shown to the following Tables 2-5.

  As is clear from the results in Table 2, Comparative Example 1 cut using the same long stretched film 1 as Example 1 has the same cutting rate, but the outer peripheral side cutting width and the inner peripheral side cutting width are the same. For this reason, defective cutting is likely to occur, and the film was scratched.

  Moreover, from the results of Table 3, Comparative Example 2 cut using the same long stretched film 2 as in Example 2 has the same cutting rate, but the cutting width on the outer peripheral side and the cutting width on the inner peripheral side are the same. , Cutting defects were likely to occur, and the film was scratched.

  Comparative Example 3 using the same long stretched film 2 as in Example 3 has the same cutting rate, but the cutting width on the outer peripheral side and the cutting width on the inner peripheral side are the same, so cutting defects are likely to occur and the film is scratched. Had occurred. In Comparative Example 4 using the same long stretched film 2 as in Example 3, the cut width on the inner peripheral side is the same as that in Example 3, but the film width becomes narrower because the cut width on the outer peripheral side and the inner peripheral side is the same. Can't get effective range.

  In addition, Example 2 using the same long stretched film 2 as Example 3 has a narrower cutting width on the inner peripheral side in order to increase the effective width, and the quality is lower than that of Example 3, but there is a problem. There is no level, and the effective range has expanded. Further, in Example 4 heated before slitting under the conditions of Example 2, the cutting rate did not change, but the occurrence of scratches and dents was reduced, and a good film could be obtained with a wide width. However, in Comparative Example 2 in which the cutting widths on the inner peripheral side and the outer peripheral side are the same with respect to the cutting conditions for obtaining this effective width, scratches and dents are increased, and a good film can be obtained. lost.

  That is, Example 3 using the same long stretched film 2 as Example 2 has a constant cut width on the outer peripheral side, while taking a larger cut width on the inner peripheral side, Occurrence decreased. Moreover, Example 4 using the same elongate stretched film 2 as Example 2 has the same cutting rate as Example 2, but by heating at the time of cutting, the cutting width on the inner peripheral side was widened with Example 3 and Equivalent film quality could be obtained.

  As is clear from the results in Table 4, Comparative Example 5 has a wider cutting width than Comparative Example 3, but long stretched film 3 of Comparative Example 5 is long stretched film 2 of Comparative Example 3. On the other hand, since the inclination in the orientation direction is large, the ease of tearing at the time of inserting the slit blade is remarkable, and adhesion residue and scratches are generated more severely.

  Further, Comparative Example 6 has a wider cutting width than that of Comparative Example 3, but the long stretched film 4 of Comparative Example 6 has a high speed film formation relative to the long stretched film 2 of Comparative Example 3. Since the tilt angle in the orientation direction on the film edge side is increased due to the high stretching stress because it is carried out under the conditions, the ease of tearing when inserting the slit blade is remarkable, so adhering debris and scratches However, it was severely generated from Comparative Example 3.

  However, Example 5 cut using the same elongated stretched film 3 as Comparative Example 5 has the same cutting rate, but even under conditions where the inclination in the orientation direction is increased by widening the cutting width on the inner peripheral side. As a result, it was difficult for cutting defects to occur, and it was possible to obtain a film of good quality free from scratches and dents. Moreover, Example 6 cut using the same long stretched film 4 as Comparative Example 6 also has the same cutting rate, but the cutting width on the inner peripheral side is widened, so that cutting defects are less likely to occur even under high-speed production conditions. Thus, it was possible to obtain a film of good quality with few scratches and dents. Moreover, in Example 7 heated before cutting | disconnection with respect to Example 6, the film without a crack and a dent could be obtained.

  Moreover, also in Examples 8 and 9 manufactured using a long stretched film containing a cellulose ester, a film having no scratches or dents is desired by ensuring the inner peripheral side cutting width wider than the outer peripheral side cutting width. Can be obtained with a film width of.

  From the above results, since the long stretched films of Examples 1 to 9 were cut so that the cut width on the inner peripheral side of the end of the long stretched film was larger than the cut width on the outer peripheral side, the occurrence of film residue was generated. It was possible to produce a long stretched film of good quality with little scratches and dents. Moreover, Example 4 and Example 7 which heated the inner peripheral side before cutting | disconnection can suppress generation | occurrence | production of a crack and a dent more compared with the case where it does not heat, and finally a crack and a dent are not seen at all. Things were obtained.

In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized as gaining. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

Claims (6)

The step of forming a long film containing a thermoplastic resin, the long film is unwound from a specific direction different from the winding direction of the film after stretching, and both end portions in the width direction of the long film are slanted An oblique stretching process in which the long film is obliquely stretched in a direction greater than 0 ° and less than 90 ° with respect to the width direction while being gripped and conveyed by a gripper of a stretching tenter, and the long stretch after the oblique stretching step In the method for producing a long stretched film having at least a slitting step of cutting both ends of the film with a slitting device, and a step of winding the long stretched film after the slitting step, the end of the long stretched film in the slitting step Cutting so that the cutting width on the inner peripheral side is larger than the cutting width on the outer peripheral side ,
In the slitting process, the inner peripheral side of the long stretched film is cut under a temperature condition higher than that of the outer peripheral side . In the said slit process, the adjustment of the said temperature is performed by heating with a heat generating apparatus before a cutting | disconnection, or adjusting the elapsed time from a diagonal stretch process, The manufacture of the elongate stretched film of Claim 1 Method. The manufacturing method of the elongate stretched film of Claim 1 or 2 which has a mechanism in which the said slit apparatus follows according to the change of the turning angle of the said elongate stretched film in the said slit process. In the slitting step, the slit device has a mechanism that can confirm the angle between the traveling direction of the traveling direction and slit blade of the long stretched film, a long stretched film according to any one of claims 1 to 3 Production method. In the oblique stretching step, the oblique traveling speed of gripping tools running on asymmetric rails stretching tenter is 25～150M / min, the production of long stretched film according to any one of claims 1-4 Method. The method for producing a long stretched film according to any one of claims 1 to 5 , wherein a film thickness of the long stretched film is 10 to 35 µm.

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