JP2010149362A - Solution film forming method and facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the reuse of chips and a various film production correspondence compatible. <P>SOLUTION: In a raw material dope preparation unit 11, raw material dope 44 is prepared. The raw material dope 44 of a flow rate Q1 is sent to an addition part 52. A chip dope supply part 50 classifies chip dope of a flow rate Q2 into chip dope 68a of a flow rate Q2a and chip dope 68b of a flow rate Q2b and sends them to the addition part 52. The addition part 52 comprises a passage through which the raw material dope 44 flows and nozzles 82a and 82b which are arranged in the passage. The nozzles 82a and 82b are arranged in turn in the flow direction of the raw material dope 44. The chip dope 68a of the flow rate Q2a is ejected in the raw material dope 44 by the nozzle 82a, and the chip dope 68b of the flow rate Q2b is ejected in the raw material dope 44 by the nozzle 82b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solution casting method facility for mixing a raw material dope containing a solvent and a polymer and a crushed dope containing a crushed product of a solvent and a polymer former.

  Polymer films (hereinafter referred to as films) are widely used as optical functional films because of their excellent light transmittance, flexibility, light weight and thin film. Among them, cellulose ester-based films using cellulose acylate have toughness and low birefringence, so that the composition of liquid crystal display devices whose market is expanding in recent years, including photographic photosensitive films. It is used for optical functional films such as a protective film for a polarizing plate as a member or an optical compensation film.

  As a main method for producing a film, there is a solution casting method. In the solution casting method, a polymer solution (hereinafter referred to as a dope) in which a polymer is dissolved in a solvent is discharged onto a support using a casting die, and the cast film formed on the support has self-supporting properties. Then, the film is peeled off from the support to form a wet film, and the wet film is further dried to form a film. The solution casting method is excellent in optical isotropy and thickness uniformity of film thickness, and can obtain a film with few contained foreign substances.

  In addition, as one step of the film manufacturing method, both ends of the film in the width direction (hereinafter referred to as ears) using clips or the like so that the wrinkles and tarmi of the film are removed or the optical properties of the film are within a desired range. In many cases, a stretching process is performed in which the sheet is gripped and stretched in the width direction. The ears of the film subjected to such stretching treatment cannot be used as a product film because grip marks such as clips remain. Then, the ear | edge part was removed from the film which passed through the extending | stretching process, and the part except an ear | edge part was used as a product film.

  Discarding the ears separated from the film causes problems such as increased costs and environmental pollution. Therefore, the dough was made by reusing the chip by dissolving the chip in a solvent together with the raw material polymer purified from the raw material cotton etc. by cutting the ear part finely using a crusher. (For example, patent document 1).

  In recent years, with the rapid increase in demand for liquid crystal display devices, a wide variety of liquid crystal display devices have been developed. Therefore, establishment of a method for producing a wide variety of films is required in accordance with all liquid crystal display devices.

  However, since the film often contains an additive, the chip obtained from the film contains an additive (for example, a retardation control agent). Therefore, when the chip is reused, it is necessary to prepare the dope by determining the mixing ratio of the chip and the raw material polymer according to the type of film to be produced.

  Also, in order to cope with the production of a wide variety of films, it is necessary to switch to a wide variety of dopes according to the film to be produced, and to perform a solution casting method. Switching from the old dope to the new dope Sometimes it is necessary to remove old dope and additives remaining in each facility. In order to reduce the burden of this removal work, just before the casting die, the tip dope in which the tip is dissolved in the solvent using a nozzle or the like is added to the raw material dope in which the raw polymer is dissolved in the solvent, and after mixing, Although this was sent to a casting die and a solution casting method was performed, as a result of pressure increase occurring in the dope during addition and mixing unevenness of both dopes due to pressure loss in the nozzle, chips and raw materials It was difficult to set a wide mixing ratio with the polymer.

  The present invention solves the above-described problems, and provides a solution casting method and equipment that make it possible to achieve both the reuse of chips and the ability to produce a wide variety of films.

  The solution film-forming method of the present invention includes a raw material dope preparation step for preparing a raw material dope containing a solvent and a raw material polymer, and a split that divides a crushed material formed from the raw material polymer and a crushed material dope containing the solvent into a plurality of parts. A step of adding each of the crushed material dopes that have passed through the dividing step to the raw material dope flowing through the flow path, and a flow including the crushed material dope and the raw material dope immediately after the adding step. A film forming step of discharging the cast dope onto a support using a casting die to form a cast film on the support, and a drying step of drying the cast film peeled off from the support. It is characterized by having.

  In the addition step, it is preferable that a plurality of the crushed dope is added to the raw material dope at a plurality of locations in a plane orthogonal to the flowing direction of the raw material dope. Further, in the adding step, it is preferable to add a plurality of the crushed dopes to the source dope in a plurality of times in the direction in which the source dope flows.

  In the adding step, it is preferable that the crushed material dope is injected toward the downstream side in the direction in the raw material dope. Further, the crushed material dope is sprayed so as to spread in the first radial direction of the flow path, and the crushed material dope is spread so as to spread in a second radial direction of the flow path that intersects the first radial direction. It is preferable to inject. Furthermore, in the addition step, it is preferable that the crushed material dope is joined to the raw material dope from the outside of the flow path. In addition, when the flow channel capacity from the raw material dope preparation step to the casting die is C1, {(1/280) × C1} or more with respect to the casting die {(1/7) × It is preferable to perform the addition step at a position where the channel capacity is C1} or less.

  The solution casting apparatus of the present invention includes a raw material dope preparation unit that prepares a raw material dope containing a solvent and a raw material polymer, and a split that divides a crushed material formed from the raw material polymer and a crushed material dope containing the solvent into a plurality of parts. And a flow path through which the raw material dope flows, an addition section provided in the flow path and having a plurality of addition devices for adding the divided crushed material dope to the raw material dope, and in communication with the flow path The casting dope including the crushed dope and the raw material dope is discharged onto a support using a casting die provided near the downstream side in the flow direction of the raw material dope of the addition unit, And a film forming unit for forming the cast film and drying the cast film peeled off from the support.

  It is preferable that a plurality of the addition devices are provided in a plane orthogonal to the direction in which the raw material dope flows. Moreover, it is preferable that a plurality of the addition devices are provided in the direction in which the raw material dope flows.

  The addition device preferably includes a nozzle having an injection port for injecting the crushed material dope in the raw material dope toward the downstream side in the direction. In addition, the plurality of addition devices include a first nozzle having a first injection port extending long in the first radial direction of the flow path, and the second radial direction intersecting the first radial direction. And a second nozzle having a second jet port extending long. Furthermore, it is preferable that an outlet of the crushed material dope flow channel through which the crushed material dope flows is provided on the inner wall of the flow channel. In addition, when the channel capacity from the raw material dope preparation unit to the casting die is C1, {(1/280) × C1} or more with respect to the casting die {(1/7) × It is preferable to provide the addition portion at a position where the channel capacity is less than or equal to C1}.

  According to the present invention, the crushed dope is divided into a plurality of pieces, and the plurality of crushed dopes are individually added to the raw material dope. Therefore, both dopes caused by pressure increase generated during the addition of the tip dope and pressure loss in the nozzle The mixing unevenness of can be suppressed. Therefore, according to the present invention, it is possible to set a wide mixing ratio of the chip and the raw material polymer, and it is possible to achieve both the reuse of the chip and the production of various kinds of films.

(Solution casting equipment)
As shown in FIG. 1, the solution casting apparatus 10 includes a raw material dope preparation unit 11, an addition unit 12, and a film forming unit 13.

(Raw material dope preparation unit)
The raw material dope preparation unit 11 includes a mixing unit 15, a dissolving unit 16, a concentration unit 17, and a storage unit 18, and prepares a raw material dope using a raw material polymer and a solvent. The mixing unit 15 includes first and second tanks 21 and 22, a dissolution tank 23, a storage tank 24, and a pump 25. A raw material polymer 26 is placed in the first tank 21, and a predetermined amount of the raw material polymer 26 is charged into the dissolution tank 23 by an attached meter. A solvent 27 is placed in the second tank 22, and a predetermined amount of the solvent 27 is introduced into the dissolution tank 23 by an attached metering pump.

  The dissolution tank 23 includes a stirring blade, and the raw material polymer 26 and the solvent 27 in the dissolution tank 23 are stirred by the rotation of the stirring blade. By this stirring, a crude solution in which the solute such as the raw material polymer 26 is not completely dissolved in the solvent 27 is obtained.

  The crude solution in the dissolution tank 23 is temporarily stored in the storage tank 24. As a result, the dissolution tank 23 is emptied, and a continuous batch system that repeatedly forms a crude solution is possible. The storage tank 24 also includes a stirring blade. By rotating the stirring blade, the crude solution is stirred and made uniform.

  The crude solution in the storage tank 24 is sent to the first heater 31 of the dissolution unit 16 via the pump 25. The first heater 31 is an in-line mixer such as a multi-tube heat exchanger or a static mixer. The crude solution is heated by the first heater 31. The heating temperature is preferably 50 to 120 ° C., and the heating time is preferably 5 to 30 minutes. By this heating, the solute such as the raw material polymer 26 necessary for the solution film formation is completely dissolved without modification, and the raw material dope is prepared. The solid content concentration of the raw material polymer contained in the raw material dope thus prepared is set to 14% by mass to 24% by mass.

  The raw material dope heated by the first heater 31 is sent to the cooler 32. The cooling device 32 cools the material dope to the boiling point or less of the main solvent. The cooled raw material dope is sent to the first filter 34 by the pump 33.

  Although not shown in the drawings, the first filter 34 includes a plurality of filter main bodies for switching and use, a cleaning device for these filter main bodies, and the like, while performing filtration on the one hand and cleaning / replacement of the filter on the other hand. Do. This enables continuous filtration of the raw material dope. The filtration method is not particularly limited. The raw material dope after filtration is sent to the concentration unit 17 by the pump 35.

  The filtered material dope is heated by the second heater 40 of the concentration unit 17 and then sent to the flash tank 41, where the material dope is concentrated by a flash concentration method. The concentrated material dope is stored in the storage tank 43 of the storage unit 18 by the pump 42. The raw material dope 44 stored in the storage tank 43 is sent to the addition unit 12 by a pump 45. In addition, the concentration part 17 is provided as needed and may be omitted.

(Additive unit)
The addition unit 12 includes a chip dope supply unit 50, an additive liquid supply unit 51, an addition unit 52, and a second filter 53.

(Chip dope supply unit)
The chip dope supply unit 50 includes third and fourth tanks 61 and 62, a dissolution tank 63, a storage tank 64, pumps 65a and 65b, and open / close valves 66a and 66b. Chips 67 are placed in the third tank 61, and a predetermined amount of chips 67 is placed in the dissolution tank 63. A solvent 27 is placed in the fourth tank 62, and a predetermined amount is charged into the dissolution tank 63 by an attached metering pump. The dissolution tank 63 and the storage tank 64 have the same structure as the dissolution tank 23 and the storage tank 24. In the dissolution tank 63, a chip dope in which the chip 67 is dissolved in the solvent 27 is prepared. Once stored. A controller (not shown) sends the chip dope 68a and the chip dope 68b to the adding unit 52 at a predetermined flow rate by controlling the opening / closing of the opening / closing valves 66a and 66b and the pumps 65a and 65b.

  In addition, it is preferable to perform a defoaming process on the chip dope between the dissolution tank 63 and the storage tank 64 or in the storage tank 64. As the defoaming treatment, it is preferable to perform centrifugal defoaming or vacuum defoaming from the viewpoint of applying as little heat as possible to the polymer. Centrifugal defoaming uses a centrifugal defoaming apparatus. The centrifugal defoaming apparatus includes a container for storing the chip dope and a stirrer that is rotatably provided and stirs the dope in the container, and the bubbles in the chip dope are removed by the centrifugal force generated by the stirring of the chip dope. Air bubbles can be removed from the chip dope by collecting them in the vicinity of the rotating shaft of the stirrer. The vacuum defoaming is performed by placing the container storing the chip dope in a reduced pressure environment lower than the atmospheric pressure. Thereby, bubbles can be removed from the chip dope. Furthermore, during vacuum defoaming, it is preferable to use a capacitor to recover the solvent evaporated from the chip dope and liquefy it, and then return it to the chip dope. In addition, when the solvent is evaporated from the chip dope in vacuum defoaming and the polymer concentration of the chip dope increases by ΔCt, a chip dope in which ΔCt is added to the target polymer concentration is prepared in advance. Above, this chip dope may be subjected to vacuum defoaming. In addition, a centrifugal defoaming device may be arranged in a reduced pressure environment, and centrifugal defoaming and vacuum defoaming may be performed simultaneously.

(Additive liquid supply unit)
The additive liquid supply unit 51 includes additive preparation systems 72 a to 72 c, open / close valves 73 a to 73 c, and a pump 74. By providing a plurality of additive preparation systems 72a to 72c, it is possible to input a plurality of types of additive liquids according to the film type. A controller (not shown) controls open / close valves 73a to 73c provided in predetermined additive blending systems 72a to 72c, and an additive liquid 77 corresponding to the film type is sent to the adding section 52 by a pump 74.

(Addition part)
As shown in FIGS. 2 and 3, the adding portion 52 includes a flow path 81 provided in the pipe 80, chip dope nozzles 82 a and 82 b, an additive liquid nozzle 83, and an inline mixer 84. A casting dope 85 is formed from the dope 44, the chip dopes 68 a and 68 b, and the additive solution 77. The channel 81 communicates the raw material dope preparation unit 11 (see FIG. 1) and the film forming unit 13 (see FIG. 1). In the flow path 81, chip dope nozzles 82a and 82b, an additive liquid nozzle 83, and an in-line mixer 84 are sequentially provided from the upstream side in the X1 direction in which the raw material dope 44 flows. The chip dope nozzles 82a and 82b are connected to the pumps 65a and 65b via a chip dope pipe (not shown), and the additive liquid nozzle 83 is connected to the pump 74 via an additive pipe (not shown). The additive liquid nozzle 83 may be provided on the upstream side in the X1 direction of each nozzle 82a, or may be provided between the nozzles 82a and 82b. Further, the chip dope pipe may be provided with a check valve or an on-off valve for preventing the backflow of the chip dopes 68a and 68b, if necessary.

(Chip dope nozzle)
The chip dope nozzle 82a has an ejection port 86a from which the chip dope 68a is ejected, and is disposed so that the ejection port 86a faces the downstream side in the X1 direction. The shape of the injection port 86a on the surface orthogonal to the X1 direction is substantially circular. In addition, it is preferable that the shape of the injection port 86a and the shape of the flow path 81 are concentric circles on the surface orthogonal to the X1 direction. The chip dope nozzle 82b has the same structure as the chip dope nozzle 82a, has an injection port 86b from which the chip dope 68b is ejected, and is arranged in the flow path 81 in the same manner as the chip dope nozzle 82a. In addition, in the plane orthogonal to the X1 direction, the cross-sectional area of the injection port 86a and the cross-section of the injection port 86b is preferably 5% or more and 100% or less, and more preferably 5% or more and 50% or less.

  The additive liquid nozzle 83 is formed so as to be flattened at the tip, and a flat injection port 87 extending in the radial direction of the flow path 81 is formed at the flat tip. The in-line mixer 84 includes a split-mixing mixer 84a and a torsion-mixing mixer 84b arranged in series in order from the upstream side. The additive liquid nozzle 83, the split mixing mixer 84a, and the torsion mixing mixer 84b are described in detail in Japanese Patent Application Laid-Open No. 2006-117904, and detailed description thereof is omitted. In addition, when the additive liquid 77 is not added to the raw material dope 44 to form the casting dope 85, the additive liquid supply unit 51 and the additive liquid nozzle 83 may be omitted. Further, when mixing the dopes 44, 68a, 68b and the like having substantially the same viscosity, the in-line mixer 84 may be omitted.

(Film forming unit)
As shown in FIG. 4, the film forming unit 13 includes a casting chamber 100, a transfer portion 101, a tenter 102, a drying chamber 103, and a winder 104, and a film 106 using a casting dope 85. Is made. In the casting chamber 100, a casting die 107 in which a discharge port for the casting dope 85 is formed, a casting drum 108 acting as a support, and a peeling roller 109 are arranged.

  The casting dope 85 is cast on the casting drum 108 that is rotating endlessly through the casting die 107 to form a casting film 111. The surface temperature of the casting drum 108 is preferably substantially constant within a range of −10 ° C. to 10 ° C. When the casting dope 85 is discharged onto such a casting drum 108, a gel-like casting film 111 is formed on the casting drum 108 by cooling the casting dope 85. The casting film 111 having self-supporting property due to gelation is peeled off as the wet film 113 from the casting drum 108 while being supported by the peeling roller 109.

  In the crossover part 101, the wet film 113 is supported by a large number of rollers, and drying proceeds while being transported. In the tenter 102, both end portions of the wet film 113 are held by holding means such as pins. An ear clip device 115 is provided downstream of the tenter 102. The ear clip device 115 cuts and removes the ear portion of the wet film 113. The cut ear portion is sent to a crusher (not shown) by air blowing, and is crushed or crushed to form a chip 67. The chip 67 is sent to the chip dope supply unit 50 (see FIG. 1) by a blower (not shown). The remaining portion is transported to the drying chamber 103 as a film 106 and subjected to a drying process in the drying chamber 103. Thereafter, the film 106 is wound up in a roll shape around the core 117 of the winder 104.

  Solvent recovery from casting chamber 100, casting die 107, casting drum 108, etc. structure, co-casting, peeling method, stretching, drying conditions of each process, handling method, curling, winding method after flatness correction The method and the film recovery method are described in detail in paragraphs [0617] to [0889] of JP-A-2005-104148, and these descriptions can also be applied to the present invention. In the above-described embodiment, the cooling gelation method is adopted in which the casting film 111 is cooled and gelled on the casting drum 108 to provide the self-supporting property. However, the casting film is dried on the band or the drum to be self-supporting. The present invention can be carried out in the same manner even with a drying method that provides support.

  Next, the operation of the present invention will be described. As shown in FIGS. 1 and 2, when the material dope 44 having a flow rate Q <b> 1 is supplied from the material dope preparation unit 11 to the adding unit 52, the material dope 44 flows in the flow path 81. The controller obtains the chip dope supply flow rate Q2 (= Q2a + Q2b), sends the chip dope 68a at the flow rate Q2a from the chip dope supply unit 50 to the chip dope nozzle 82a, and sends the chip dope 68b at the flow rate Q2b to the chip dope nozzle 82b. Thereafter, the chip dope nozzle 82 a injects a chip dope 68 a having a flow rate Q 2 a into the material dope 44, and the chip dope nozzle 82 b injects a chip dope 68 b having a flow rate Q 2 b into the material dope 44. Thus, the chip dope 68a and the chip dope 68b are sequentially added to the raw material dope 44 flowing through the flow path 81 from the upstream side in the X1 direction toward the downstream side. The additive liquid supply unit 51 sends an additive liquid 77 having a predetermined flow rate to the additive liquid nozzle 83, and the additive liquid nozzle 83 injects the additive liquid 77 into the raw material dope 44. Next, the in-line mixer 84 mixes the raw material dope 44, the respective chip dope nozzles 82a and 82b, and the additive liquid 77 to produce a casting dope 85 having a target concentration Cx.

  The chip dope supply flow rate Q2 is determined based on the target concentration Cx of the chip dope in the casting dope 85 and the flow rate Q1 of the raw material dope 44. Here, the target density Cx is expressed by Q2 / (Q1 + Q2) · 100 (%). Note that the flow rates Q2a and Q2b of the chip dopes 68a and 68b may be the same or different from each other. Further, the flow rate of the raw material dope 44 flowing in the vicinity of the injection ports 86a and 86b of the chip dope nozzles 82a and 82b is V1, the flow rates of the chip dopes 68a and 68b injected from the chip dope nozzles 82a and 82b are V2a and V2b, and the flow path 81. Q1 is represented by {V1 · (S1−S2a−S2b)}, and Q2 is represented by (V2a · S2b), and the cross sectional areas S2a and S2b of the injection ports 86a and 86b of the chip dope nozzles 82a and 82b. S2a + V2b · S2b). In order to uniformly mix the raw material dope 44 and the chip dopes 68a and 68b, it is preferable to determine Q2a and Q2b so that V1 and V2a and V1 and V2b are substantially equal.

  When the chip dope is added once to the raw material dope 44, if the target concentration Cx is large (for example, Cx is 50% or more and 90% or less), a local pressure increase occurs in the vicinity of the nozzle of the chip dope nozzle. End up. When a large chip dope nozzle having a large cross-sectional area of the injection port is used to prevent a pressure increase, although the occurrence of a local pressure increase can be suppressed, the target concentration Cx is small (for example, Cx is 3% or more and 50%). % Or less), it becomes difficult to stabilize the amount of chip dope added. On the other hand, in order to stabilize the addition amount of the chip dope when the target concentration Cx is small, a small chip dope nozzle having a small cross-sectional area of the injection port may be used, but when the target concentration Cx is large, the chip is added. The pressure loss in the dope nozzle is increased.

  In the present invention, a plurality of chip dope nozzles for adding chip dope to the raw material dope 44 are provided, and the flow rate of the chip dope ejected from the chip dope nozzle can be adjusted independently according to the target concentration Cx. The target concentration Cx can be set in a wide range (0% or more and 100% or less) while avoiding adverse effects due to pressure increase due to the addition position and pressure loss at the nozzle. Therefore, according to the present invention, it is possible to achieve both the reuse of the chip and the production of various kinds of films.

  As shown in FIG. 1, the position where the adding portion 52 is provided is preferably a position where the pipe capacity C2 is 1/280 to 1/7 of the pipe capacity C1, and more specifically, the nozzles 82a, 82b, It is preferable that the position of the most upstream nozzle among 83 is a position where the pipe capacity C2 is 1/280 to 1/7 of the conventional pipe capacity C1. Thereby, the amount of removal work that occurs when switching from the old dope to the new dope can be reduced.

  In the above-described embodiment, two chip dope nozzles are used. However, the present invention is not limited to this, and three or more chip dope nozzles are used to connect opening / closing valves and pipes connecting each chip dope nozzle and the storage tank 64. A pump may be provided. Further, when the target concentration Cx is relatively small, the chip dope injection may be stopped at some of the chip dope nozzles, and the chip dope injection may be performed at the remaining chip dope nozzles. And when target density | concentration Cx is 0%, what is necessary is just to stop the injection | pouring of the chip dope from all the chip dope nozzles, and all are included in this invention.

  In the above embodiment, a plurality of chip dope nozzles are sequentially provided from the upstream side in the X1 direction, and the chip dope is added to the raw material dope in a plurality of times from the X1 direction, but the present invention is not limited to this and is shown in FIG. Thus, in the flow channel 81, a plurality of chip dope nozzles 151 to 153 are arranged so that the respective injection ports 151a to 153a are positioned in a plane orthogonal to the X1 direction (see FIG. 2), and a plurality of chip dope nozzles are arranged. From 151 to 153, a plurality of chip dopes having independently adjusted flow rates may be injected into the raw material dope. The plurality of chip dope nozzles 151 to 153 are preferably arranged in the radial direction of the flow path 81. A bundle of a plurality of chip dope nozzles arranged so that the injection ports are positioned in a plane orthogonal to the X1 direction may be sequentially arranged in the X1 direction.

  In the above-described embodiment, the addition unit 52 having the chip dope nozzles 82a and 82b having the substantially circular discharge port on the surface orthogonal to the X1 direction is used. However, the present invention is not limited to this, and the addition shown in FIG. The part 161 or the addition part 162 shown in FIG. 7 may be used. The addition part 161 and the addition part 162 are the addition part 52 except using the chip dope nozzles 167a and 167b having the flat injection ports 166a and 166b similar to the additive liquid nozzle 83 instead of the chip dope nozzles 82a and 82b. The configuration is the same as (see FIG. 2), and detailed description and illustration of the same parts are omitted. In addition part 161, as shown in Drawing 6, chip dope nozzles 167a and 167b are provided so that the longitudinal direction of flat injection port 166a and the longitudinal direction of flat injection port 166b may become parallel. Further, in the adding section 162, as shown in FIG. 7, the chip dope nozzles 167a and 167b are arranged such that the longitudinal direction of the flat injection port 166a and the longitudinal direction of the flat injection port 166b intersect at an angle θ (see FIG. 8). Is provided. The crossing angle θ is not particularly limited, but the chip dope nozzle may be provided so that the longitudinal direction of the flat nozzles of all the chip dope nozzles equally divides the circumferential direction of the flow path when viewed from the X1 direction. preferable.

  In FIG. 7, the additive liquid nozzle 83 and the chip dope nozzle 167b are provided so that the longitudinal direction of the flat ejection port 87 and the longitudinal direction of the flat ejection port 166b intersect, but the present invention is not limited to this. The additive liquid nozzle 83 and the chip dope nozzle 167b may be provided so that the longitudinal direction of the flat ejection port 87 and the longitudinal direction of the flat ejection port 166a are parallel to each other.

  In addition, as a plurality of chip dope nozzles, a nozzle having a flat ejection port and a nozzle having a substantially circular ejection port may be combined. In this case, the nozzle having the flat ejection port may be disposed on the upstream side in the X1 direction, and the nozzle having the discharge port having a substantially circular cross-sectional shape may be disposed on the downstream side in the X1 direction, or vice versa.

  In the above embodiment, the chip dope nozzle is provided as an adding device in the flow path through which the raw material dope 44 flows. However, the present invention is not limited to this, and as shown in FIG. You may use the addition part 180 which merges chip dope from the outside. The addition unit 180 includes a raw material dope pipe 181 through which the raw material dope 44 flows, chip dope pipes 182a through 182b through which the chip dopes 68a to 68b flow, and junctions 183a through 183b that are sequentially provided in the raw material dope pipe 181 toward the direction X1. Consists of Outlet 183a-183b of chip dope piping 182a-182b is provided in the inner wall surface of raw material dope piping 181 in merge part 183-183b, respectively, and raw material dope piping 181 and chip dope piping 182a-182b are connected. By using the addition unit 180, a plurality of chip dopes can be sequentially added to the raw material dope 44 from the X1 direction. Any one of the chip dope pipes 182a to 182b may be replaced with the above-described chip dope nozzle. Note that the flow rate of the raw material dope 44 flowing in the vicinity of the outlets 183a and 184b of the chip dope nozzles 182a and 182b is V1, and V2a and V2b of the chip dopes 68a and 68b flowing into the raw material dope pipe 181 via the outlets 183a and 184b, If the cross-sectional area S1 of the raw material dope pipe 181 in the cross section orthogonal to the X1 direction and the cross-sectional areas S2a and S2b of the outlets 183a and 184b in the cross section orthogonal to the X1 direction, Q1 is represented by (V1 · S1), Q2 is represented by (V2a · S2a + V2b · S2b).

  In the above embodiment, the outlets of the chip dope pipes 182a to 182b are sequentially provided in the X1 direction on the inner wall of the raw material dope pipe 181 constituting the flow path of the raw material dope 44. However, the present invention is not limited to this, and the chip You may provide the exit of dope piping 182a-182b in the circumferential direction of the inner wall of the raw material dope piping 181. FIG.

(Polymer concentration)
The polymer concentration of the raw material dope 44 is preferably 18% by mass or more and 25% by mass or less. The polymer concentration of the chip dopes 68a and 68b is preferably 18% by mass or more and 25% by mass or less. Note that the polymer concentrations of the chip dope 68a and the chip dope 68b may be the same or different.

(Raw polymer)
Hereinafter, the raw material polymer used when preparing the raw material dope 44 in the present invention will be described.

In the present embodiment, cellulose acylate is used as a raw material polymer, and cellulose triacetate (TAC) is particularly preferable as the cellulose acylate. Among cellulose acylates, those in which the substitution degree of the acyl group to the hydroxyl group of cellulose satisfies all of the following formulas (I) to (III) are more preferable. In the following formulas (I) to (III), A and B represent the substitution degree of the acyl group with respect to the hydrogen atom in the hydroxyl group of cellulose, A is the substitution degree of the acetyl group, and B is 3 carbon atoms. The substitution degree of the acyl group of ˜22. In addition, it is preferable that 90 weight% or more of TAC is a particle | grain of 0.1-4 mm. However, the polymer that can be used in the present invention is not limited to cellulose acylate.
(I) 2.5 ≦ A + B ≦ 3.0
(II) 0 ≦ A ≦ 3.0
(III) 0 ≦ B ≦ 2.9

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group having 2 or more carbon atoms. The degree of acyl substitution means the ratio at which the hydroxyl groups of cellulose are esterified at each of the 2-position, 3-position and 6-position (the substitution degree is 1 in the case of 100% esterification).

  The total degree of acylation substitution, that is, the value of DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. Further, the value of DS6 / (DS2 + DS3 + DS6) is preferably 0.28 or more, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. Here, DS2 is a ratio in which the hydroxyl group at the 2-position in the glucose unit is substituted with an acetyl group (hereinafter referred to as the acyl substitution degree at the 2-position), and DS3 is the hydroxyl group at the 3-position in the glucose unit. The DS6 is a ratio in which the hydroxyl group at the 6-position is substituted with an acetyl group in the glucose unit (hereinafter referred to as the acyl substitution degree at the 6-position). Called).

  Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more kinds of acyl groups are used, it is preferable that one of them is an acetyl group. The sum of the degree of substitution of the hydroxyl groups at the 2nd, 3rd and 6th positions by acetyl groups is DSA, and the sum of the degree of substitution of the hydroxyl groups at the 2nd, 3rd and 6th positions by acyl groups other than acetyl groups When DSB is DSB, the value of DSA + DSB is preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88.

  The DSB is preferably 0.30 or more, particularly preferably 0.7 or more. Further, 20% or more of DSB is preferably a substituent at the 6-position hydroxyl group, more preferably 25% or more, further preferably 30% or more, and particularly preferably 33% or more. Further, the value of DSA + DSB at the 6-position of cellulose acylate is 0.75 or more, more preferably 0.80 or more, and particularly preferably cellulose acylate of 0.85 or more. These cellulose acylates By using, a solution (dope) having better solubility can be produced. In particular, when a non-chlorine organic solvent is used, a dope having excellent solubility, low viscosity and excellent filterability can be produced.

  Cellulose, which is a raw material for cellulose acylate, may be obtained from either linter or pulp.

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

(solvent)
Solvents for preparing the dope include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol, Diethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (eg, tetrahydrofuran, methyl cellosolve, etc.). In the present invention, the dope refers to a polymer solution or dispersion obtained by dissolving or dispersing a raw polymer or chip in a solvent.

  Among the above halogenated hydrocarbons, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. From the viewpoint of physical properties such as solubility of TAC, peelability of cast film from the support, mechanical strength and optical properties of the film, one or several kinds of alcohols having 1 to 5 carbon atoms are mixed in addition to dichloromethane. It is preferable to do. The content of alcohol is preferably 2 to 25% by weight, more preferably 5 to 20% by weight, based on the entire solvent. Examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, etc., but methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

  Recently, a solvent composition not using dichloromethane has been studied for the purpose of minimizing the influence on the environment. In this case, an ether having 4 to 12 carbon atoms, a ketone having 3 to 12 carbon atoms, an ester having 3 to 12 carbon atoms, and an alcohol having 1 to 12 carbon atoms are preferable. Sometimes used. For example, a mixed solvent of methyl acetate, acetone, ethanol, and n-butanol can be mentioned. These ethers, ketones, esters and alcohols may have a cyclic structure. A compound having two or more functional groups of ether, ketone, ester and alcohol (that is, —O—, —CO—, —COO— and —OH) can also be used as the solvent.

  Details of cellulose acylate are described in paragraphs [0140] to [0195] of JP-A-2005-104148, and these descriptions can also be applied to the present invention. The same applies to additives such as solvents and plasticizers, deterioration inhibitors, UV absorbers (UV agents), optical anisotropy control agents, retardation control agents, dyes, matting agents, release agents, and release accelerators. JP-A-2005-104148 describes in detail in paragraphs [0196] to [0516], and these descriptions can also be applied to the present invention.

  In the above embodiment, a dope composed of a raw material polymer and a solvent is used as a raw material dope, but the present invention is not limited to this, and a dope composed of additives such as a matting agent and a plasticizer in addition to the raw material polymer and the solvent. May be used as a raw material dope.

  Next, in order to confirm the presence or absence of the effect of the present invention, Experiments 1 to 4 were performed. Detailed description will be given in Experiment 1, and in Experiments 2 to 4, description of the same conditions as in Experiment 1 will be omitted, and only different parts will be described.

(Experiment 1)
In Experiment 1, using the addition part 52 shown in FIG. 2, the tip dopes 68a and 68b are added to the raw material dope 44 to prepare casting dopes having the target concentration Cx shown in Table 1, respectively. The solution casting method was performed using In order to evaluate the mixing unevenness of the casting dope, the colorant was added to the chip dope 68a, and the colorant was added to the chip dope 68b. The flow rates V2a and V2b of the chip dopes 68a and 68b were in a range of ± 30% of the flow rate V1 of the raw material dope 44. The cross-sectional area ratio of the flow path 81 and the injection ports 86a and 86b was 5: 1: 1, respectively.

(Experiment 2)
Experiment 2 was the same as Experiment 1 except that the addition section 162 shown in FIG. The cross-sectional area ratio of the flow path 81 and the flat injection ports 166a and 166b was 10: 3: 3.

(Experiment 3)
Experiment 3 was the same as Experiment 1 except that the addition unit 180 shown in FIG. 9 was used instead of the addition unit 52. However, instead of the chip dope pipe 182b of the addition unit 180, the chip dope nozzle 167b shown in FIG. 6 is provided at a position corresponding to the merge part 183b of the raw material dope pipe 181. The cross-sectional area ratio of the flow path of the raw material dope pipe 181, the flat injection port 166 a, and the flow path of the chip dope pipe 182 a was 4: 1: 4.

(Experiment 4)
Experiment 4 was the same as Experiment 1 except that only the chip dope nozzle 82a was used as the addition device.

In Table 1, the evaluation result of the mixing nonuniformity of casting dope in Experiments 1-4 is shown. Utilizing the fact that the measured value of the haze of the film varies depending on the addition concentration of the chip dope, the method for evaluating the mixing unevenness was performed as follows. A 200 mm long × 200 mm wide sample film was cut out from the film obtained by the solution casting method of each experiment 1-4. The sample film was divided into 5 parts in the longitudinal direction and the transverse direction, and haze was measured for a total of 25 sample pieces. A direct reading type haze meter HGM-2DP manufactured by Suga Test Instruments Co., Ltd. was used for haze measurement. Among the measured values of the obtained haze, the difference between the maximum value and the minimum value was taken as the range. The mixing unevenness was evaluated based on the following criteria for this range.
A: The range was 0.1 or less.
○: The range was greater than 0.1 and less than or equal to 0.2.
(Triangle | delta): The range was larger than 0.2 and was 0.4 or less.
X: The range was larger than 0.4.

  As shown in Table 1, according to the present invention, it was found that the target concentrations of the raw material dope and the chip dope can be set widely while suppressing the occurrence of uneven mixing.

It is explanatory drawing which shows the outline | summary of a solution casting apparatus and demonstrates the detail of a raw material dope preparation unit and an addition unit. It is a perspective view which shows the outline | summary of a 1st addition part. It is sectional drawing of the flow path in the surface orthogonal to X1 direction. It is explanatory drawing which shows the outline | summary of a film forming unit. It is sectional drawing of the 2nd addition part in the surface orthogonal to X1 direction. It is a perspective view which shows the outline | summary of a 3rd addition part. It is a perspective view which shows the outline | summary of a 4th addition part. It is sectional drawing about the surface orthogonal to the X1 direction of a 4th addition part. It is a perspective view which shows the outline | summary of the 5th addition part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solution film forming equipment 11 Raw material dope preparation unit 12 Addition unit 13 Film forming unit 26 Raw material polymer 27 Solvent 44 Raw material dope 52, 161, 162, 180 Addition part 67 Tip 68a, 68b Tip dope 81 Channel 82a, 82b Tip dope nozzle 84 In-line mixer 85 Casting dope 86a, 86b Injection port

Claims (14)

A raw material dope preparation step for preparing a raw material dope including a solvent and a raw material polymer;
A dividing step of dividing the crushed material formed of the raw material polymer and the crushed material dope containing the solvent into a plurality of parts;
An addition step of individually adding a plurality of the crushed material dopes that have undergone the dividing step to the raw material dope flowing through the flow path,
Immediately after the adding step, a casting dope containing the crushed material dope and the raw material dope is discharged onto a support using a casting die, and a film forming step of forming a casting film on the support,
And a drying step of drying the cast film peeled off from the support.   2. The solution casting method according to claim 1, wherein in the adding step, a plurality of the crushed material dopes are added to the raw material dope at a plurality of locations in a plane orthogonal to the flow direction of the raw material dope.   3. The solution casting method according to claim 1, wherein in the adding step, a plurality of the crushed material dopes are added to the raw material dope in a plurality of times in a direction in which the raw material dope flows.   4. The solution casting method according to claim 2, wherein in the adding step, the crushed material dope is sprayed toward the downstream side in the direction in the raw material dope. Injecting the crushed material dope so as to spread in the first radial direction of the flow path,
The solution casting method according to claim 4, wherein the crushed material dope is sprayed so as to spread in a second radial direction of the flow path intersecting the first radial direction.   6. The solution casting method according to claim 2, wherein in the adding step, the crushed material dope is joined to the raw material dope from the outside of the flow path.   When the flow path capacity from the raw material dope preparation step to the casting die is C1, {(1/280) × C1} or more and {(1/7) × C1} or less based on the casting die The solution casting method according to any one of claims 1 to 6, wherein the adding step is performed at a position where the flow path capacity becomes. A raw material dope preparation unit for preparing a raw material dope including a solvent and a raw material polymer;
A division part for dividing the crushed material formed from the raw material polymer and the crushed material dope containing the solvent into a plurality of parts,
A flow path through which the raw material dope flows, and an addition unit having a plurality of addition devices provided in the flow path and adding the divided crushed material dope to the raw material dope,
The casting dope including the crushed dope and the raw material dope is discharged to a support using a casting die that is in communication with the flow path and is provided in the vicinity of the addition portion downstream in the flow direction of the raw material dope. And a film-forming unit for forming a cast film on the support and drying the cast film peeled off from the support.   9. The solution casting apparatus according to claim 8, wherein a plurality of the addition devices are provided in a plane orthogonal to the direction in which the raw material dope flows.   The solution casting apparatus according to claim 8 or 9, wherein a plurality of the addition devices are provided in a direction in which the raw material dope flows.   The said addition apparatus contains the nozzle which has an injection nozzle which injects the said crushed material dope toward the downstream of the said direction in the said raw material dope, The any one of Claims 8 thru | or 10 characterized by the above-mentioned. Solution casting equipment.   The plurality of addition devices include a first nozzle having a first injection port extending long in the first radial direction of the flow path, and a length in the second radial direction that intersects the first radial direction. The solution casting apparatus according to claim 11, further comprising a second nozzle having a second injection port extending.   The solution casting apparatus according to any one of claims 8 to 12, wherein an outlet of the crushed dope flow channel through which the crushed dope flows is provided on an inner wall of the flow channel.   When the channel capacity from the raw material dope preparation unit to the casting die is C1, {(1/280) × C1} or more and {(1/7) × C1} or less based on the casting die The solution casting apparatus according to any one of claims 8 to 13, wherein the addition section is provided at a position where the flow path capacity is reduced.

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