JP2009066982A - Solution film forming method and cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean the periphery of a casting drum certainly without reducing productivity. <P>SOLUTION: A drum cleaning apparatus 38 is installed above the periphery 32a of a casting drum and between a stripping-off roller and a decompressing chamber. A cleaning gas 76 is blown against the periphery 32a of the casting drum. In the cleaning gas 76 dry ice particles 73 are contained. The foreign substances adhering to the periphery 32a are removed from the periphery 32a by collision with the dry ice particles 73. The removed foreign substances flow in the X or Y direction together with the cleaning gas 76. A counter wind 91 prevents the cleaning gas 76 flowing in the X direction from leaking out of the chamber 63. A counterwind 91 prevents the cleaning gas 76 flowing in the Y direction from leaking out of the chamber 63. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solution film forming method and a cleaning apparatus for cleaning a support by removing foreign substances adhering to the surface of the support.

  Polymer films (hereinafter referred to as “films”) are widely used as optical functional films because they have excellent light transmission properties and flexibility and can be reduced in weight. Among them, cellulose ester film using cellulose acylate has toughness and low birefringence, so that it is a component of liquid crystal display devices whose market has been expanding in recent years, including photographic photosensitive films. It is used for an optical functional film such as a protective film for a polarizing plate or an optical compensation film.

  One method for producing a film is a solution casting method. In this solution casting method, a dope is prepared by dissolving a polymer such as cellulose triacetate in a mixed solvent containing dichloromethane or methyl acetate as a main solvent. The dope is discharged from a casting die to form a casting bead and cast on a metal support such as a casting drum or an endless band to form a casting film (hereinafter referred to as “casting process”). The cast film is dried or cooled on the support to become self-supporting, and then peeled off from the support as a film (hereinafter referred to as “wet film”). The dried product is wound up as a film.

  In the casting process, foreign substances mainly composed of fatty acids, fatty acid esters, fatty acid metal salts, and the like are precipitated from the casting film by continuous operation for a long time, and so-called plate-out occurs in which the foreign substances adhere to the support surface. . When plate-out occurs, foreign matter on the surface of the support is transferred to the film. As the foreign matter is transferred to the film surface, the optical characteristics become uneven.

Conventionally, as a cleaning method of the support surface, a wet treatment method (Patent Document 1) in which the support surface is continuously wiped using a nonwoven fabric soaked with an organic solvent or the like, a solvent treatment, corona discharge treatment, plasma on the film surface. A foreign matter removal method (Patent Document 2) is disclosed in which treatment such as discharge treatment and flame treatment is performed to remove foreign matter on the film surface.
JP 2003-1654 A JP 2001-89590 A

However, in the wet processing method disclosed in Patent Document 1, it is necessary to interrupt the continuous casting and periodically perform the cleaning operation of the support, resulting in a reduction in production efficiency. In the foreign matter removing method of Patent Document 2, it is desirable to perform the foreign matter removing process under conditions that do not affect the film characteristics, but it is not easy to find such conditions.

  In recent years, in order to cope with the further increase in demand for film, it is strongly desired to increase the film forming speed. Therefore, there has been a demand for reliably washing the support without decreasing the film forming speed.

  An object of this invention is to provide the solution casting method and washing | cleaning apparatus which can wash | clean a support body reliably, without reducing productivity.

  In order to achieve the above object, the present invention forms a casting film by casting a dope containing a polymer and a solvent on a support that runs endlessly, and peels the casting film from the support. In the solution casting method for producing a film by taking and drying, the film is sublimable with respect to the surface of the support after the casting film is peeled off and before the dope is cast. A cleaning gas spraying member is sprayed with a cleaning gas spraying member to remove foreign matter adhering to the surface of the support, and an opposing wind is applied to the cleaning gas flowing along the surface of the support by an opposing wind spraying member. It is characterized by spraying.

  The counter air blowing member includes a first counter air blowing member provided on the upstream side in the running direction of the support relative to the cleaning gas spray member, and a downstream side in the running direction of the support relative to the cleaning gas spray member. It is preferable to consist of the 2nd opposing wind blowing member provided in the side. It is preferable that a chamber covers an area where the cleaning gas and the counter air flow are performed.

  It is preferable to prevent the cleaning gas and the counter air from leaking out of the chamber by a labyrinth seal provided between the chamber and the support.

  The foreign matter is preferably sucked by suction means. It is preferable that the ratio of the wind speed Vi of the cleaning gas and the wind speed Vc of the counter wind is 0.3 or more and less than 5.0. The sublimable particles are preferably dry ice particles.

  The present invention provides a film by casting a dope containing a polymer and a solvent on a support that runs endlessly to form a cast film, and then peeling the cast film from the support and drying it. In a cleaning apparatus that removes foreign matter on the surface of the support and cleans the surface of the support, after the casting film is peeled off, A cleaning gas spraying member that sprays a cleaning gas containing sublimable particles on the surface of the support before the dope is cast, and a counter air flow against the cleaning gas that flows along the surface of the support It sprays with a counter wind spray member, It is characterized by the above-mentioned.

  According to the present invention, the cleaning gas containing sublimable particles is sprayed onto the surface of the support after the cast film has been peeled off and before the dope is cast on the surface of the support. By removing the foreign matter, the support can be cleaned without stopping the production of the film. Moreover, scattering of foreign matters can be prevented by blowing counter air against the cleaning gas flowing along the surface of the support. Thereby, a support body can be wash | cleaned reliably, without affecting manufacture of a film.

[First Embodiment]
FIG. 1 shows a schematic diagram of a solution casting apparatus 10 used in the first embodiment. The solution casting apparatus 10 includes a stock tank 11, a casting chamber 12, a pin tenter 13, a clip tenter 14, a drying chamber 15, a cooling chamber 16, and a winding chamber 17.

  The stock tank 11 includes a stirring blade 11b and a jacket 11c that are rotated by a motor 11a, and a dope 21 that is a raw material for the film 20 is stored therein. The dope 21 in the stock tank 11 is adjusted by the jacket 11c so that the temperature is substantially constant. Further, the rotation of the stirring blade 11b keeps the dope 21 in a uniform quality while suppressing the aggregation of polymers and the like. A gear pump 25 and a filtration device 26 are installed downstream of the stock tank 11, and the dope 21 is sent to the casting die 30 through these.

  In the casting chamber 12, a casting die 30, a casting drum 32 as a support, a peeling roller 34, temperature control devices 35 and 36, a decompression chamber 37, and a drum cleaning device 38 are installed. The casting drum 32 is rotated in the X direction by a driving device (not shown), and the dope 21 is discharged from the casting die 30 toward the peripheral surface 32a of the rotating casting drum 32 during rotation, and the peripheral surface 32a. A casting film 33 is formed on the surface.

  The temperature in the casting chamber 12 and the casting drum 32 is set to a temperature at which the casting film 33 is easily cooled and solidified (gelled) by the temperature control devices 35 and 36. The casting film 33 is peeled off from the casting drum 32 by the peeling roller 34 when the gel strength having self-supporting properties is reached.

  The decompression chamber 37 is disposed on the upstream side in the X direction with respect to the casting die 30 and keeps the inside of the chamber 37 at a negative pressure. As a result, the back surface of the casting bead (the surface that comes into contact with the peripheral surface of the casting drum 32 later) is reduced to a desired pressure, and the influence of the accompanying wind generated by the casting drum 32 rotating at high speed is reduced. Then, a stable casting bead is formed between the casting die 30 and the casting drum 32, and the casting film 33 with little film thickness unevenness is formed.

  The material of the casting die 30 is formed of a material having high corrosion resistance against a mixed solution of electrolyte aqueous solution, dichloromethane, methanol, and the like, and a low coefficient of thermal expansion. It is preferable to use a liquid contact surface finishing accuracy of the casting die 30 of 1 μm or less in terms of surface roughness and a straightness of 1 μm / m or less in any direction.

  The peripheral surface 32a of the casting drum 32 is subjected to a chrome plating process and has sufficient corrosion resistance and strength. The temperature control device 36 circulates the heat transfer medium in the heat transfer medium flow path in the casting drum 32 in order to keep the temperature of the peripheral surface 32a of the casting drum 32 at a desired temperature. The heat transfer medium is maintained at a desired temperature, and the temperature of the peripheral surface 32a of the casting drum 32 is maintained at a desired temperature by passing through the heat transfer medium flow path in the casting drum 32.

  The width of the casting drum 32 is not particularly limited, but it is preferable to use a casting drum having a width within a range of 1.1 to 2.0 times the casting width of the dope. The material of the casting drum 32 is preferably made of stainless steel, and more preferably made of SUS316 so as to have sufficient corrosion resistance and strength. The chrome plating treatment applied to the peripheral surface 32a of the casting drum 32 is preferably so-called hard chrome plating with a Vickers hardness of Hv 700 or more and a film thickness of 2 μm or more.

  In the casting chamber 12, a condenser (condenser) 53 for condensing and recovering the evaporated organic solvent and a recovery device 54 for recovering the condensed and liquefied solvent are provided. The organic solvent condensed and liquefied by the condenser 53 is recovered by the recovery device 54. The recovered solvent is regenerated by a regenerator and then reused as a dope preparation solvent.

  As shown in FIGS. 1 and 2, the drum cleaning device 38 is provided above the peripheral surface 32 a of the casting drum and between the peeling roller 34 and the decompression chamber 37. The drum cleaning device 38 removes foreign matter adhering to the peripheral surface 32a of the casting drum and cleans the casting drum 32. The foreign matters mainly include fatty acid esters, fatty acids, fatty acid metal salts and the like precipitated from the casting film on the casting drum.

  The drum cleaning device 38 includes a dry ice generation unit 60, a gas supply unit 61, a cleaning nozzle 62, a chamber 63, an exhaust unit 64, counter air nozzles 65 and 66, and air blowing units 67 and 68. The gas supply unit 61 and the first supply port 62 a of the cleaning nozzle are connected by a pipe 70. The dry ice generator 60 and the first supply port 62 b of the cleaning nozzle are connected by a pipe 71.

  The dry ice generator 60 generates dry ice particles 73 having a predetermined particle size. The generated dry ice particles 73 are supplied to the second supply port 62 b of the cleaning nozzle 62 via the pipe 71. The gas supply unit 61 includes a gas tank and is filled with a carrier gas 74 compressed to a predetermined pressure. The carrier gas 74 is composed of an inert gas such as nitrogen. The gas supply unit 61 supplies a predetermined amount of carrier gas 74 to the first supply port 62 a of the cleaning nozzle 62 via the pipe 70. The carrier gas need not be limited to an inert gas, and may be air, for example. In addition, the dry ice particles are generated in advance by the dry ice generator, and then the dry ice particles are sent to the nozzle. However, the present invention is not limited to this. For example, liquid carbon dioxide may be fed into a nozzle, and solid dry ice particles may be generated in the nozzle.

  The cleaning nozzle 62 is attached to the center of the chamber 63 in the X direction, and the outlet 62c of the cleaning nozzle 62 is directed to the peripheral surface 32a of the casting drum. The cleaning nozzle 62 is formed with a first flow path (not shown) that communicates between the first supply port 62a and the outlet 62c, and a second flow path that communicates between the second supply port 62b and the first flow path. Two flow paths (not shown) are formed. The carrier gas 74 supplied to the first channel is mixed with the dry ice particles 73 from the second channel. A gas 76 mixed with the dry ice particles (hereinafter referred to as “cleaning gas”) is blown onto the peripheral surface 32a of the casting drum through the blowout port 62c. Hereinafter, the area where the cleaning gas 76 is blown is referred to as a cleaning area 78.

  When the cleaning gas 76 is sprayed onto the peripheral surface 32a of the casting drum, the dry ice particles 73 contained in the cleaning gas 76 collide with foreign matter attached to the peripheral surface 32a. Due to this collision, the foreign matter is crushed and removed from the peripheral surface. Thereby, the foreign material adhering to the surrounding surface of a casting drum can be removed, without leaving a washing trace. The removed foreign matter flows together with the cleaning gas 76 in the X direction or the Y direction opposite to the X direction.

  The chamber 63 is substantially box-shaped, and an exhaust port 63a is formed on the upper surface thereof. The exhaust port 63 a is connected to the exhaust part 64 by a pipe 80. The exhaust unit 64 exhausts the inside of the chamber 63 to reduce the pressure to a predetermined pressure. A suction port 63 b is formed on the lower surface of the chamber 63. Through the suction port 63b, the vicinity of the cleaning area 78 is sucked by the reduced pressure in the chamber 63. Due to the suction in the vicinity of the cleaning area 78, the foreign matter is sucked into the chamber 63 together with the cleaning gas 76.

  A plurality of labyrinth seals 83 are attached to the periphery of the lower surface of the chamber 63 to seal between the chamber 63 and the peripheral surface 32a of the casting drum. The labyrinth seal 83 prevents the cleaning gas 76 from leaking out of the chamber 63.

  As described above, by sucking the foreign matter together with the cleaning gas 76, the foreign matter is prevented from scattering out of the chamber 63. Even if foreign matter is not sucked together with the cleaning gas 76, the labyrinth seal 83 prevents the cleaning gas 76 containing foreign matter from flowing out of the chamber 63. Thus, the foreign matter removed from the peripheral surface 32a of the casting drum does not scatter outside the chamber 63, and the cleaning gas 76 used for removing the foreign matter is prevented from flowing out of the chamber 63. Even during the casting of the dope 21, the casting drum 32 can be cleaned without affecting the casting film 33 or the casting bead.

  Further, while the cleaning gas 76 and the foreign matter are sucked continuously for a long time, the air around the chamber 63 is drawn into the chamber 63 by the suction. When the amount of wind drawn into the chamber 63 increases, condensation occurs in the chamber 63 that has become extremely cold due to the use of the dry ice particles 73. If this condensation falls on the peripheral surface 32a of the casting drum, the surface shape of the casting film 33 may be affected. With respect to this problem, by providing a labyrinth seal 83 at the peripheral edge of the lower surface of the chamber 63, the inflow of wind drawn into the chamber 63 is prevented and the occurrence of condensation is suppressed.

  The counter air nozzle 65 is attached to the X direction end of the chamber 63 and downstream of the cleaning nozzle 62 in the X direction. The air outlet 65a of the counter wind nozzle 65 is directed to the peripheral surface 32a of the casting drum. On the other hand, the counter air nozzle 66 is attached to the X direction end of the chamber 63 and upstream of the cleaning nozzle 62 in the X direction. The air outlet 66a of the counter wind nozzle 66 is directed to the peripheral surface 32a of the casting drum. These opposed wind nozzles 65 and 66 are connected to the blower section by pipes 85 and 86.

  The counter air 90 from the counter air nozzle 65 is blown against the cleaning gas 76 flowing in the X direction. By the blowing of the counter air 90, the cleaning gas 76 and the counter air 90 rise into the chamber 63 together with the foreign matter and are sucked. The counter air 91 from the counter air nozzle 66 is blown against the cleaning gas 76 flowing in the Y direction. As the counter air 91 is blown, the cleaning gas 76 and the counter air 90 rise to the chamber 63 together with the foreign substances and are sucked.

  The blowing of the counter winds 90 and 91 prevents the cleaning gas 76 flowing in the X direction or the Y direction from leaking out of the chamber 63. Further, foreign matter flowing in the X direction or the Y direction together with the cleaning gas 76 is prevented from being scattered outside the chamber 63. In addition, as an opposing wind, inert gas, such as air and nitrogen gas, is mentioned. The counter air may include dry ice particles as in the cleaning gas.

  Here, the wind speed Vi of the cleaning gas 76 is not less than 80 m / sec and not more than 200 m / sec. Moreover, the wind speed Vc of the opposing winds 90 and 91 is 10 m / sec or more and 250 m / sec or less. Further, the ratio (Vi / Vc) between the wind speed Vi of the cleaning gas and the wind speed of the counter wind Vc is preferably 0.3 or more and 4.5 or less, more preferably 0.3 or more and 3.0 or less, and 0.3 or more and 1 .5 or less is most preferable. If the ratio (Vi / Vc) is less than 0.3, the amount of air that forms CO2 snow is too low, and cleaning becomes impossible. On the other hand, if the ratio (Vi / Vc) exceeds 4.5, the air volume of CO2 snow is too high, so even if the chamber exists, the outside air leakage cannot be suppressed and there is a possibility of causing the casting stop. high.

Moreover, it is preferable that the blowing angle β of the opposing winds 90 and 91 is 20 ° or more and 80 ° or less. The distance L1 between the cleaning nozzle outlet 62c and the counter-air nozzle outlet 65a (or the distance between the cleaning nozzle outlet 62c and the counter-air nozzle outlet 66a) L1 is 0.02 m to 0.6 m. Preferably there is.

  On the downstream side of the casting chamber 12, a crossover part 41, a pin tenter 13, and a clip tenter 14 are installed in this order. The crossover part 41 introduces the wet film 39 peeled off by the conveying roller 42 into the pin tenter 13. The pin tenter 13 has a large number of pin plates that pass through and hold both ends of the wet film 39, and the pin plates travel on the track. During this traveling, dry air is sent to the wet film 39, and the wet film 39 is dried while traveling to become the film 20.

  The clip tenter 14 has a number of clips that hold both ends of the film 20, and these clips travel on the stretching track. During this traveling, a drying air is sent to the film 20, and the film 20 is dried while being stretched in the film width direction. Desired optical characteristics are imparted to the film 20 exiting the clip tenter 14 by the stretching process under the predetermined conditions in the clip tenter 14.

  An ear clip device 43 is provided downstream of the pin tenter 13 and the clip tenter 14, respectively. The ear clip device 43 cuts off the ears at both ends of the film. The cut ears are sent to the crusher 44 by air sending, and are crushed and reused as a raw material such as a dope.

  A large number of rollers 47 are provided in the drying chamber 15, and drying is performed by winding the film 20 around these rollers and transporting them. An adsorption recovery device 48 is connected to the drying chamber 15, and the solvent evaporated from the film 20 is absorbed and recovered.

  A cooling chamber 16 is provided on the outlet side of the drying chamber 15, and the film 20 is cooled in this cooling chamber 16 until it reaches room temperature. A forced static elimination device (static elimination bar) 49 is provided downstream of the cooling chamber 16 to neutralize the film 20. Further, a knurling roller 50 is provided on the downstream side of the forced static eliminating device 49, and knurling is applied to both side edges of the film 20. A winding machine 51 having a press roller 52 is installed in the winding chamber 17, and the film 20 is wound around the winding core in a roll shape.

  Next, an example of a method for producing a film with the solution casting apparatus 10 will be described. In the stock tank 11, the temperature of the dope 21 is adjusted to 25 ° C. to 35 ° C. by flowing a heat transfer medium inside the jacket 11c, and is always uniformed by the rotation of the stirring blade 11b. The dope 21 appropriately applied is passed through the stock tank 11 from the stock tank 11 to the filtration device 26 by the gear pump 25, thereby removing impurities in the dope 21. Then, the dope 21 is cast from the casting die 30 onto the peripheral surface of the casting drum 32 cooled to a predetermined surface temperature while forming a casting bead. The temperature of the dope 21 at the time of casting is preferably kept substantially constant within a range of 30 ° C to 35 ° C.

  The casting drum 32 is rotated in the X direction by a driving device (not shown). By this rotation, the peripheral surface 32a of the casting drum is traveling at a constant speed (30 m / min or more and 200 m / min or less). Further, the temperature of the peripheral surface 32a of the casting drum is adjusted so as to be substantially constant within a range of −10 ° C. to + 10 ° C. When the casting drum 32 cooled in this way is used, the casting film 33 can be gelled to have a self-supporting property. The temperature of the peripheral surface is managed by the temperature adjustment device 36, and the temperature of the peripheral surface is held at a predetermined value. As the casting film 33 is cooled, a cross-linking point that forms a crystal base is formed, and gelation of the casting film 33 is promoted.

  After the casting film 33 becomes self-supporting due to the progress of gelation, it is peeled off from the casting drum 32 by the peeling roller 34 to form a wet film 39, and this wet film 39 is pinned by the conveying roller 42. 13 is sent.

  The internal temperature of the casting chamber 12 is adjusted by the temperature control device 35 so as to be substantially constant within a range of 10 ° C. to 57 ° C. Inside the casting chamber 12, the dope 21 to be cast and the solvent in the casting film 33 are volatilized and floated. Therefore, in the present embodiment, this floating solvent is condensed into a condensate by the condenser 53, then recovered in the recovery device 54, further regenerated by the regenerator, and reused as a dope preparation solvent.

  As shown in FIG. 2, the cleaning gas 76 is blown onto the peripheral surface 32 a of the casting drum by the drum cleaning device 38. The cleaning gas 76 is mixed with dry ice particles 73 so that the dry ice particles collide with foreign matter adhering to the peripheral surface 32a. The foreign particles are removed from the peripheral surface 32a by the collision of the dry ice particles. The removed foreign matter flows in the X direction or the Y direction together with the cleaning gas 76. The chamber 63 is used to suck in foreign substances that flow in the X direction or the Y direction together with the cleaning gas. Further, the blowing of the counter air 90 prevents the cleaning gas 76 flowing in the X direction from leaking out of the chamber 63. Similarly, the blowing of the counter air 91 prevents the cleaning gas 76 flowing in the Y direction from leaking out of the chamber.

  In the pin tenter 13, a large number of pins are inserted and fixed to both side ends of the wet film 39, and then the drying is promoted while the wet film 39 is conveyed to form the film 20. Then, the film 20 still containing the solvent is fed into the clip tenter 14. At this time, it is preferable that the residual solvent amount of the film 20 immediately before being sent to the clip tenter 14 is 50 to 150% by weight.

  In the clip tenter 14, drying is promoted while the film 20 is conveyed after the both ends of the film 20 are sandwiched by a large number of clips that run endlessly by the movement of the chain. At this time, the film 20 is stretched by increasing the distance between the facing clips (film width) and applying tension in the width direction of the film 20. Thus, by the stretching process in the width direction of the film 20, the molecules in the film 20 are oriented, and a desired retardation value can be imparted to the film 20.

  The film 20 that has exited the pin tenter 13 and the clip tenter 14 is cut at both end portions by the edge-cutting device 43. The film 20 whose both end portions are cut is wound up by the winder 51 of the winding chamber 17 through the drying chamber 15 and the cooling chamber 16. Further, both end portions cut by the ear-cutting device 43 are crushed by the crusher 44 to be reused as a dope preparation chip.

  The film 20 wound up by the winder 51 is preferably at least 100 m in the longitudinal direction (casting direction). The width of the film 20 is preferably 600 mm or more, and more preferably 1400 mm or more and 2500 mm or less. The present invention is also effective when the width is greater than 2500 mm. Furthermore, the present invention is also applied when manufacturing a thin film having a thickness of 20 μm to 80 μm.

  Hereinafter, the raw materials used when preparing the dope 21 in the present invention will be described.

In the present embodiment, cellulose acylate is used as the polymer, and cellulose triacetate (TAC) is particularly preferable as the cellulose acylate. And among the cellulose acylates, the substitution degree of the acyl group to the hydroxyl group of cellulose is represented by the following formulas (I) to (III), and A and B represent the substitution degree of the acyl group to the hydrogen atom in the hydroxyl group of cellulose. , A is the degree of substitution of the acetyl group, and B is the degree of substitution of the acyl group having 3 to 22 carbon atoms. 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 group of cellulose is 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, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. Here, DS2 is a ratio in which the hydrogen of the hydroxyl group at the 2-position in the glucose unit is substituted by an acyl group (hereinafter referred to as “acyl substitution degree at the 2-position”), and DS3 is the hydroxyl group at the 3-position in the glucose unit. The hydrogen is substituted with an acyl group (hereinafter referred to as “acyl substitution degree at the 3-position”), and DS6 is the ratio of the hydrogen at the 6-position hydroxyl group substituted with an acyl group (hereinafter referred to as “acyl substitution degree at the 3-position”). "The 6-position acyl substitution degree").

  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 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 of a hydroxyl group at the 6-position, more preferably 25% or more, further preferably 30% or more, and particularly preferably 33% or more. Further, the DSA + DSB value at the 6-position of the cellulose acylate is 0.75 or more, more preferably 0.80 or more, and particularly preferably cellulose acylate of 0.85 or more. By using it, a dope with 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 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, olenoyl 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.

  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.).

  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 from cast film support, mechanical strength and optical properties of film, one or several kinds of alcohols having 1 to 5 carbon atoms are mixed in addition to dichloromethane. It is preferable. 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, and n-butanol, but methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

  Recently, a solvent composition that does not use dichloromethane has been studied for the purpose of minimizing the impact 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. In addition, 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 a 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. It is described in detail in paragraphs [0196] to [0516] of Kai 2005-104148, and these descriptions can also be applied to the present invention.

  In the solution casting method of the present invention, when casting a dope, two or more types of dopes are simultaneously co-cast and laminated, or a plurality of dopes are sequentially co-cast. Sequential lamination co-casting can be performed. In addition, you may combine both casting. When performing simultaneous lamination and co-casting, a casting die to which a feed block is attached may be used, or a multi-manifold casting die may be used. However, it is preferable that at least one of the thickness of the layer on the air surface side and the thickness of the layer on the support side is 0.5 to 30% of the thickness of the entire film in the film composed of multiple layers by co-casting. . In addition, when performing simultaneous lamination and co-casting, it is preferable that the high-viscosity dope is enveloped by the low-viscosity dope when the dope is cast from the die slit to the support, and is formed from the die slit to the support. Of the casting beads, the dope in contact with the outside world preferably has a higher alcohol composition ratio than the inner dope.

  From casting die, decompression chamber, support structure, co-casting, peeling method, stretching, drying conditions for each process, handling method, curl, winding method after flatness correction, solvent recovery method, film recovery method Until now, it is described in detail in paragraphs [0617] to [0889] of JP-A-2005-104148, and these descriptions can also be applied to the present invention.

[Second Embodiment]
As shown in FIG. 3, unlike the first embodiment, the drum cleaning device 98 of the second embodiment of the present invention cleans the casting drum without using a chamber. Since the components other than the drum cleaning device are the same as those in the first embodiment, description thereof will be omitted.

  The drum cleaning device 98 includes a dry ice generation unit 100, a gas supply unit 101, a cleaning nozzle 102, counter air nozzles 105 and 106, and air blowing units 107 and 108. The gas supply unit 101 and the first supply port 102a of the cleaning nozzle are connected by a pipe 110. The dry ice generator 100 and the second supply port 102b of the cleaning nozzle are connected by a pipe 111.

  The dry ice generation unit 100 generates dry ice particles 113 having a predetermined particle size. The generated dry ice particles 113 are supplied to the second supply port 62 b of the cleaning nozzle 102 via the pipe 111. The gas supply unit 101 is composed of a gas tank and is filled with a carrier gas 114 compressed to a predetermined pressure. The carrier gas 114 is composed of an inert gas such as nitrogen. The gas supply unit 101 supplies a predetermined amount of carrier gas 114 to the first supply port 102 a of the cleaning nozzle 102 via the pipe 110.

  The cleaning nozzle 102 is installed so that the air outlet 102c faces the peripheral surface 32a of the casting drum. The cleaning nozzle 102 is formed with a first channel (not shown) that communicates between the first supply port 102a and the outlet 102c, and a second channel that communicates between the second supply port 102b and the first channel. Two flow paths (not shown) are formed. The carrier gas 114 supplied to the first channel is mixed with the dry ice particles 113 from the second channel. A gas 116 (hereinafter referred to as “cleaning gas”) mixed with the dry ice particles 113 is blown onto the peripheral surface 32a of the casting drum through the blowout port 102c.

  The counter air nozzle 105 is attached to the downstream side of the cleaning nozzle 102 in the X direction. The air outlet 105a of the counter wind nozzle 105 is directed to the peripheral surface 32a of the casting drum. On the other hand, the counter air nozzle 106 is attached to the upstream side of the cleaning nozzle 102 in the X direction. The air outlet 106a of the counter wind nozzle 66 is directed to the peripheral surface 32a of the casting drum. These opposed wind nozzles 105, 106 are connected to the air blowing units 107, 108 by pipes 118, 119.

  The counter air 120 from the counter air nozzle 105 is blown against the cleaning gas 116 flowing in the X direction. By spraying the counter air 120, the cleaning gas 116 and the counter air 120 rise together with the foreign matter above the peripheral surface 32a. The soared foreign matter, cleaning gas 116 and counter air 120 are sucked by a suction nozzle 124. The counter air 121 from the counter air nozzle 106 is blown against the cleaning gas 116 flowing in the Y direction. By blowing the counter air 121, the cleaning gas 116 and the counter air 121 rise above the peripheral surface 32a together with the foreign matter. The soaring foreign matter, cleaning gas 116 and counter air 121 are sucked by the suction nozzle 125.

  The cleaning gas 116 flowing in the X direction or the Y direction is prevented from reaching the casting film 33 and the casting bead by the blowing of the counter winds 120 and 121. In addition, foreign matters flying up by blowing the opposing winds 120 and 121 are sucked by the suction nozzles 124 and 125, so that the foreign matters are prevented from being scattered.

  Here, the wind speed Vi of the cleaning gas 116 is 80 m / sec or more and 200 m / sec or less. Moreover, the wind speed Vc of the counter winds 120 and 121 is 10 m / sec or more and 250 m / sec or less. The ratio (Vi / Vc) between the wind speed Vi of the cleaning gas and the wind speed of the counter wind Vc is preferably 0.3 or more and 3.0 or less, more preferably 0.3 or more and 2.5 or less, and 0.3 or more and 1 .5 or less is most preferable. If the ratio (Vi / Vc) is less than 0.3, the amount of air that forms CO2 snow is too low, and cleaning becomes impossible. On the other hand, if the ratio (Vi / Vc) exceeds 3.0, the air volume of the CO2 snow is too high, so that the effect of wind leakage on the product part occurs and the corresponding part does not become a product.

  Moreover, it is preferable that spray angle (beta) of the opposing winds 120 and 121 is 20 degrees or more and 80 degrees or less. The distance L2 between the cleaning nozzle outlet 102c and the counter-air nozzle outlet 105a (the distance between the cleaning nozzle outlet 102c and the counter-air nozzle outlet 106a) L2 is 0.02 m to 0.6 m. It is preferable.

[Third Embodiment]
As shown in FIG. 4, the drum cleaning device 138 of the third embodiment of the present invention cleans the casting drum without using a chamber, unlike the first embodiment. Further, unlike the first and second embodiments, the number of opposed wind nozzles is reduced from two to one. Since the components other than the drum cleaning device are the same as those in the first embodiment, description thereof will be omitted.

  The drum cleaning device 138 includes a dry ice generation unit 140, a gas supply unit 141, a cleaning nozzle 142, a counter air nozzle 145, and a blower unit 147. The gas supply unit 141 and the first supply port 142a of the cleaning nozzle are connected by a pipe 150. The dry ice generator 140 and the second supply port 142b of the cleaning nozzle are connected by a pipe 151.

  The dry ice generator 140 generates dry ice particles 153 having a predetermined particle size. The generated dry ice particles 153 are supplied to the second supply port 142b of the cleaning nozzle 142 via the pipe 151. The gas supply unit 141 includes a gas tank, and is filled with a carrier gas 154 compressed to a predetermined pressure. The carrier gas 154 is composed of an inert gas such as nitrogen. The gas supply unit 141 supplies a predetermined amount of carrier gas 154 to the first supply port 142 a of the cleaning nozzle 142 via the pipe 150.

  The cleaning nozzle 142 is installed such that the air outlet 142c faces the peripheral surface 32a of the casting drum. The cleaning nozzle 142 is formed with a first flow path (not shown) that communicates between the first supply port 142a and the blowout port 142c, and a second flow path that communicates between the second supply port 142b and the first flow path. Two flow paths (not shown) are formed. The carrier gas 154 supplied to the first flow path is mixed with the dry ice particles 153 from the second flow path. A gas 156 mixed with the dry ice particles 153 (hereinafter referred to as “cleaning gas”) is blown onto the peripheral surface 32a of the casting drum via the blowout port 142c.

  The counter air nozzle 145 is attached to the downstream side of the cleaning nozzle 142 in the X direction. The air outlet 145a of the counter wind nozzle 145 is directed to the peripheral surface 32a of the casting drum. The counter wind nozzle 145 is connected to the blower 147 by a pipe 158.

  The counter air 160 from the counter air nozzle 145 is blown against the cleaning gas 156 flowing in the X direction. By the blowing of the counter air 160, the cleaning gas 156 and the counter air 160 rise above the peripheral surface 32a together with the foreign matter. The soared foreign matter, cleaning gas 156 and counter air 160 are sucked by the suction nozzle 164. Thereby, the cleaning gas 156 flowing in the X direction is prevented from reaching the casting film 33 and the casting bead. In addition, the foreign matter flying up by the blowing of the counter air 160 is sucked by the suction nozzle 164, thereby preventing the foreign matter from scattering.

  Here, the wind speed Vi of the cleaning gas 156 is 80 m / sec or more and 200 m / sec or less. Moreover, the wind speed Vc of the counter wind 160 is 10 m / sec or more and 250 m / sec or less. The ratio (Vi / Vc) between the wind speed Vi of the cleaning gas and the wind speed of the counter wind Vc is preferably 0.3 or more and 1.7 or less, and more preferably 1.0 or more and 1.5 or less. If the ratio (Vi / Vc) is less than 0.3, the amount of air that forms CO2 snow is too low, and cleaning becomes impossible. On the other hand, when the ratio (Vi / Vc) exceeds 1.5, the air volume of the CO2 snow increases, and the film has a very slight influence such as wind unevenness.

  Further, the spray angle α of the cleaning gas 156 is preferably 70 ° or more and 110 ° or less. Further, the spray angle β of the counter air 160 is preferably 20 ° or more and 80 ° or less. Moreover, it is preferable that the distance L3 between the air outlet 142c of the cleaning nozzle and the air outlet 145a of the counter wind nozzle is 0.02 m or more and 0.6 m or less.

  Hereinafter, the present invention will be specifically described with reference to examples. Here, Examples 1 to 9 and Comparative Examples 1 and 2 correspond to the first embodiment, Examples 10 to 17 and Comparative Examples 3 to 5 correspond to the second embodiment, and Example 18 To 20 and Comparative Examples 6 to 9 correspond to the third embodiment. However, the present invention is not limited to these examples.

[Example 1]
As shown in FIG. 1, as the casting drum 32 used in the solution casting apparatus 10, a cylindrical drum having a diameter of 1000 mm and the peripheral surface 32a subjected to chrome plating and mirror finishing was used. The dope 21 was cast with a dry thickness of 80 μm to form a cast film 33. The casting film 33 having self-supporting property was peeled off by the peeling roller 34 to obtain a wet film 39. In the pin tenter 13 and the clip tenter 14, the wet film 39 was dried to a predetermined residual solvent amount to obtain the film 20. In addition to visual observation, it was confirmed by a video camera or the like whether foreign matter had adhered to the peripheral surface 32a of the casting drum. Moreover, it was confirmed using IR (infrared spectrophotometer), GCMS (gas chromatograph gravimetric analyzer), and NMR (nuclear magnetic resonance apparatus) whether or not the fatty acid was contained in the foreign matter.

  As shown in FIGS. 1 and 2, the drum cleaning device 38 is installed above the peripheral surface 32 a of the casting drum and between the peeling roller 34 and the decompression chamber 37. A cleaning nozzle 62 was attached to the chamber 63 of the drum cleaning device, and a cleaning gas 76 was sprayed from the cleaning nozzle 62 onto the peripheral surface 32 a of the casting drum in the chamber 63. Dry ice particles 73 were mixed in the cleaning gas 76. By spraying the cleaning gas 76, the foreign matter adhering to the peripheral surface 32a of the casting drum was removed. The removed foreign matter was sucked from the suction port 63b of the chamber. Further, a labyrinth seal 83 is provided on the peripheral edge of the lower surface of the chamber 63, and the labyrinth seal 83 prevents the cleaning gas 76 from flowing out of the chamber 63. In addition, the labyrinth seal 83 prevents the air around the chamber 63 from flowing into the chamber 63. Further, the counter air 90 was blown against the cleaning gas 76 flowing in the X direction, and the counter air 91 was sprayed against the cleaning gas 76 flowing in the Y direction.

  Also, the wind speed Vi of the cleaning gas is 100 m / second, the wind speed Vc of the counter wind is 100 m / second, the ratio (Vi / Vc) of the wind speed Vi of the cleaning gas to the wind speed Vc of the counter wind is 1, and the spray angle β of the counter wind is The distance L1 between the air outlet 62c of the cleaning nozzle and the air outlet 65a of the counter air nozzle (the distance between the air outlet 62c of the cleaning nozzle and the air outlet 66a of the counter air nozzle) L1 was 0.1 m.

[Example 2]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 1, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 150 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Example 3]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 1, the cleaning gas wind speed Vi is 30 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Was 0.3, the blowing angle β of the counter wind was 45 °, and the distance L1 was 0.1 m.

[Example 4]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of the first embodiment, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the counter air blowing angle β is 45 °, and the distance L1 is 0.1 m.

[Example 5]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of the first embodiment, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the blowing angle β of the counter wind is 20 °, and the distance L1 is 0.1 m.

[Example 6]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of the first embodiment, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the blowing angle β of the counter wind is 70 °, and the distance L1 is 0.1 m.

[Example 7]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of the first embodiment, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the counter air blowing angle β is 45 °, and the distance L1 is 0.05 m.

[Example 8]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 1, the cleaning gas wind speed Vi is 250 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 2.5, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Example 9]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 1, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 50 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 3, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 1]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 1, the cleaning gas wind speed Vi is 250 m / sec, the counter wind speed Vc is 50 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 5, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 2]
The conditions were the same as in Example 1 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning device of Example 1, the cleaning gas wind speed Vi is 250 m / sec, the counter wind speed Vc is 55 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 4.55, the counter wind blowing angle β is 45 °, and the distance L1 is 0.1 m.

[Example 10]
As shown in FIG. 3, the drum cleaning device 98 was installed between the peeling roller 34 and the decompression chamber 37 above the peripheral surface 32 a of the casting drum. A cleaning gas 116 was sprayed from the cleaning nozzle 102 of the drum cleaning device onto the peripheral surface 32a of the casting drum. Dry ice particles 113 were mixed in the cleaning gas 116. By spraying the cleaning gas 116, foreign matter adhering to the peripheral surface 32a of the casting drum was removed. Further, the counter wind 120 was blown against the cleaning gas 116 flowing in the X direction, and the counter wind 121 was blown against the cleaning gas 116 flowing in the Y direction. Further, the foreign matter that has risen above the peripheral surface 32 a due to the blowing of the counter air 120 and 121 was sucked by the suction nozzles 124 and 125.

  Also, the wind speed Vi of the cleaning gas is 100 m / second, the wind speed Vc of the counter wind is 100 m / second, the ratio (Vi / Vc) of the wind speed Vi of the cleaning gas to the wind speed Vc of the counter wind is 1, and the spray angle β of the counter wind is The distance L1 between the air outlet 102c of the cleaning nozzle and the air outlet 105a of the counter air nozzle (the distance between the air outlet 102c of the cleaning nozzle and the air outlet 106a of the counter air nozzle) L1 was 0.1 m.

[Example 11]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 150 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Example 12]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the counter air blowing angle β is 45 °, and the distance L1 is 0.1 m.

[Example 13]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the blowing angle β of the counter wind is 20 °, and the distance L1 is 0.1 m.

[Example 14]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the blowing angle β of the counter wind is 70 °, and the distance L1 is 0.1 m.

[Example 15]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Is 1.5, the blowing angle β of the counter wind is 45 °, and the distance L1 is 0.5 m.

[Example 16]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 30 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). Was 0.3, the blowing angle β of the counter wind was 45 °, and the distance L1 was 0.1 m.

[Example 17]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 250 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 2.5, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 3]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 50 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 3, the counter air blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 4]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions related to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 250 m / sec, the counter wind speed Vc is 80 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 3.125, the blowing angle β of the counter wind was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 5]
The conditions were the same as in Example 10 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 10, the cleaning gas wind speed Vi is 100 m / sec, the counter wind speed Vc is 35 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 2.86, the counter wind blowing angle β was 45 °, and the distance L1 was 0.1 m.

[Example 18]
As shown in FIG. 4, the drum cleaning device 138 was installed between the peeling roller 34 and the decompression chamber 37 above the peripheral surface 32 a of the casting drum. A cleaning gas 156 was blown from the cleaning nozzle 142 of the drum cleaning device onto the peripheral surface 32a of the casting drum. Dry ice particles 153 were mixed in the cleaning gas 156. By spraying the cleaning gas 156, foreign matter adhering to the peripheral surface 32a of the casting drum was removed. Further, the counter air 160 was blown against the cleaning gas 116 flowing in the X direction. In addition, the foreign matter that has risen above the peripheral surface 32 a due to the blowing of the counter air 160 is sucked by the suction nozzle 164.

  Further, the cleaning gas wind speed Vi is 100 m / second, the counter wind speed Vc is 100 m / second, the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc) is 1, and the cleaning gas spray angle α is 30 °, the blowing angle β of the counter air was 45 °, and the distance L1 between the air outlet 142c of the cleaning nozzle and the air outlet 145a of the counter air nozzle was 0.1 m.

[Example 19]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 100 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1, the cleaning gas spray angle α was 30 °, the counter air spray angle β was 45 °, and the distance L1 was 0.1 m.

[Example 20]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1.5, the cleaning gas spray angle α was 30 °, the counter air spray angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 6]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 30 m / sec, the counter wind speed Vc is 100 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 0.3, the cleaning gas spray angle α was 30 °, the counter wind spray angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 7]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 80 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1.875, the cleaning gas spray angle α is 30 °, the counter air spray angle β is 45 °, and the distance L1 is 0.1 m.

[Comparative Example 8]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 150 m / sec, the counter wind speed Vc is 85 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1.76, the cleaning gas spray angle α was 30 °, the counter air spray angle β was 45 °, and the distance L1 was 0.1 m.

[Comparative Example 9]
The test was performed under the same conditions as in Example 18 except for the conditions related to the drum cleaning apparatus. Of the conditions relating to the drum cleaning apparatus of Example 18, the cleaning gas wind speed Vi is 200 m / sec, the counter wind speed Vc is 115 m / sec, and the ratio of the cleaning gas wind speed Vi to the counter wind speed Vc (Vi / Vc). 1.74, the cleaning gas spray angle α was 30 °, the counter air spray angle β was 45 °, and the distance L1 was 0.1 m.

表１は実施例１〜９及び比較例１〜２の結果を、表２は実施例１０〜１７及び比較例３〜５の結果を、表３は実施例１８〜２０及び比較例６〜９の結果を示す。表１〜表３の「評価」のうち「◎」は、フイルムの製造に流延ドラムの洗浄を行っても、そのフイルムの製造には影響を与えないことを示している。「○」は、フイルムの製造に流延ドラムの洗浄を行っても、そのフイルムの製造にはほとんど影響を与えないことを示している。「△」は、流延ドラムの洗浄を行ってもドープの流延を停止には至らないが、その間に製造されたフイルムは製造品にはならないことを示している。「×」は、流延ドラムの洗浄を行うと、ドープの流延の停止に至ることを示している。 [Results of Examples and Comparative Examples]

Table 1 shows the results of Examples 1-9 and Comparative Examples 1-2, Table 2 shows the results of Examples 10-17 and Comparative Examples 3-5, and Table 3 shows Examples 18-20 and Comparative Examples 6-9. The results are shown. Of the “evaluations” in Tables 1 to 3, “◎” indicates that even if the casting drum is washed in the production of the film, the production of the film is not affected. “◯” indicates that even if the casting drum is washed in the production of the film, the production of the film is hardly affected. “Δ” indicates that the casting of the dope does not stop even if the casting drum is washed, but the film produced during that time does not become a manufactured product. “X” indicates that the casting of the dope is stopped when the casting drum is cleaned.

It is the schematic which shows a solution casting apparatus. It is a front view which shows the drum cleaning apparatus of 1st Embodiment. It is a front view which shows the drum cleaning apparatus of 2nd Embodiment. It is a front view which shows the drum cleaning apparatus of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solution casting apparatus 32 Casting drum 32a (casting drum) peripheral surface 38 Drum cleaning apparatus 60,100,140 Dry ice production | generation part 61,101,141 Gas supply part 62,102,142 Cleaning nozzle 63 Chamber 64 Exhaust Portions 65, 66, 105, 106, 145 Opposed air nozzles 67, 68, 107, 108, 147 Air blowing portions 73, 113, 153 Dry ice particles 74, 114, 154 Carrier gas 76, 116, 156 Cleaning gas 83 Labyrinth seal 90 , 91, 120, 121, 160 Counter air flow 124, 125, 164 Suction nozzle

Claims (8)

A solution for producing a film by casting a dope containing a polymer and a solvent on a support that runs endlessly to form a cast film, and peeling the cast film from the support and drying it. In the film forming method,
After the casting film is peeled off and before the dope is cast, a cleaning gas containing sublimable particles is sprayed by a cleaning gas spraying member on the surface of the support, and the support To remove foreign matter adhering to the surface of
A solution casting method, wherein an opposing wind is blown against the cleaning gas flowing along the surface of the support by an opposing wind blowing member.   The counter air blowing member includes a first counter air blowing member provided on the upstream side in the running direction of the support relative to the cleaning gas spray member, and a downstream side in the running direction of the support relative to the cleaning gas spray member. The solution casting method according to claim 1, comprising a second opposing wind blowing member provided on the side.   3. The solution casting method according to claim 1, wherein an area where the cleaning gas and the counter air are blown is covered with a chamber.   4. The solution casting method according to claim 3, wherein a labyrinth seal provided between the chamber and the support prevents the cleaning gas and the counter air from leaking out of the chamber.   5. The solution casting method according to claim 1, wherein the foreign matter is sucked by a suction means.   6. The solution casting method according to claim 1, wherein a ratio of a wind speed Vi of the cleaning gas and a wind speed Vc of the counter wind is 0.3 or more and less than 5.0.   The solution casting method according to any one of claims 1 to 6, wherein the sublimable particles are dry ice particles. A solution for producing a film by casting a dope containing a polymer and a solvent on a support that runs endlessly to form a cast film, and peeling the cast film from the support and drying it. In a cleaning apparatus that is used for film-forming equipment, removes foreign matter on the surface of the support, and cleans the support.
A cleaning gas spraying member that sprays a cleaning gas containing sublimable particles on the surface of the support after the casting film is peeled off and before the dope is cast,
A cleaning apparatus comprising: an opposing wind blowing member that blows an opposing wind against the cleaning gas flowing along the surface of the support.

Images