KR20140042652A - Solution film-forming method - Google Patents

Abstract

Coat a drum (29) with dope (13) having cellulose acylate (11) dissolved in a solvent (12). Harden a coated film (32) by gelling on the circumference surface (29a) of the drum (29) and then detach the coated film. Maintain the temperature of the coated film (32) not to lower below (gelling point (TG) of the dope (13) - 3)°C till the detached point. Adjust the temperature of the coated film (32) by temperature control of the circumference surface (29a) of the drum (29). By a first intake air part (35), send, to the coated film (32), gas in a fair wind within the range of 15-30 m/s inclusive as a relative speed with respect to movement speed of the coated film. Make an angle between the direction of the gas in a fair wind and the direction perpendicular to the film surface of the coated film to be in a range of greater than 0 degrees and less than or equal to 45 degrees. By the supply of the gas, foam the coated film on the film surface of the coated film (32). [Reference numerals] (11) Cellulose acylate; (12) Solvent; (13) Dope; (137) Air blower; (18) First tender; (19) Second tender; (34) Temperature controller; (37) Air blower; (38) Controller; (42) Aspirator

Description

SOLUTION FILM-FORMING METHOD

The present invention relates to a solution film forming method for producing a cellulose acylate film.

A cellulose acylate film is cut | disconnected to the dimension according to a use, and is used. Although cutting | disconnection may consist only of a cellulose acylate film before combining with another member, after combining with another member, it may be made with the member. An example of the latter is a case where a polarizing plate is produced. When manufacturing a polarizing plate, after bonding a polarizing film and the cellulose acylate film used as a protective film which protects this, a cutting process is performed. The same applies to a case where one of the pair of protective films disposed on both sides of the polarizing film is replaced by an optical compensation film (including a retardation film). In this way, the optical compensation film is sometimes used as a protective film.

In order to obtain a polarizing plate, when cut | disconnecting to the objective for the film of the multilayer structure which consists of bonding of a polarizing film and a protective film (henceforth a multilayer structure film), it cut | disconnects from one film surface with respect to a multilayer structure film. Press the blade tightly to cut it. When the multilayer structure film is cut in this manner, cracks may occur from the cut surface formed by the cutting into the protective film. The protection film which a crack generate | occur | produces in this way by cutting is evaluated that processability is bad, and the commodity value also becomes remarkably low also about the polarizing plate obtained.

Moreover, in various display products, such as a personal computer, a liquid crystal television, and a tablet, thickness reduction and cost down progress, and with this flow, there is a request for further thinning also in a protective film. By the way, the generation | occurrence | production of such a crack is easy to occur especially when the very thin protective film in the range of 25 micrometers or more and 40 micrometers or less is used.

As a manufacturing method of the cellulose acylate film used for optical uses, such as a polarizing plate as mentioned above, there exists a solution film forming method. In the solution film forming method, a dope in which a polymer is dissolved in a solvent is cast on a support to form a cast film, the cast film is hardened and peeled off, and the peeled cast film, that is, a wet film, is dried to produce a polymer film. to be. As the support for softening the dope, a drum which rotates in the circumferential direction with the rotational axis at the center of the circular cross section, or a belt that rotates in the longitudinal direction over the circumferential surfaces of at least two rollers, is used. From the manufacturing limit, the size of the drum is about 3.5 m in cross-sectional circular shape, and the circumferential length of the circumferential surface on which the flexible film is formed is only about 3.5 pi (unit; m). On the other hand, the belt can be produced with a length of 100 m or more, and can make the distance (hereinafter referred to as the casting film conveying distance) longer than the drum until the film is peeled off after the casting film is formed. The solution film is largely divided into a dry gelation method and a cooling gelation method by the method of hardening the cast film.

In the dry gelation method, the cast film is dried to a desired dry level, and the cast film is gelled and hardened by this drying. That is, a casting film is dried and hardened to the extent that the wet film after peeling can be conveyed. It is common to perform drying by blowing dry air into a casting film. In order to further accelerate this drying, the drying air is heated to warm air, or further, the casting film is heated by heating the support. In order to harden a flexible film | membrane by drying, since it requires longer time than hardening by the following cooling gelation method, it is customary to use a belt instead of a drum as a support body.

On the other hand, in the cooling gelation method, by actively cooling the casting membrane, the gel is formed in a state in which the solvent residual rate is very high, and the gelation proceeds until it hardens to the extent that it can be transported even when peeled off. This method can harden a cast film | membrane in a shorter time according to a dry gelation method, and as a support body, a drum may be sufficient in some cases.

As described above, in either of the dry gelation method and the cooling gelation method, the cast film is gelled and hardened.

In comparison with the dry gelation method and the cooling gelation method described above, the latter can be peeled off from the support while the solvent residual rate is high, which is remarkably superior in terms of production efficiency. However, the cellulose acylate film obtained by the cooling gelation method is inferior to the cellulose acylate film obtained by the dry gelation method from the viewpoint of the above processability.

Many proposals are made about the solution film forming method using a dry gelation method and the solution film forming method using a cooling gelation method, respectively. For example, as a solution film formation method using a dry gelation method, in the method of JP-A-2000-239403, the temperature of the support is in the range of 1 ° C. or higher and 80 ° C. or lower, and at the peeling position at which the flexible film is peeled off from the support. , Spray the gas stream. According to this method, the film which has a desired retardation can be manufactured efficiently.

In addition, Japanese Patent Laid-Open No. 2006-306059 proposes a method of gelling a cast membrane by performing both drying and cooling. In Japanese Patent Laid-Open No. 2006-306059, the surface temperature of the belt as the support is set to -20 to 40 ° C. This Japanese Patent Laid-Open No. 2006-306059 winds a belt around a pair of rollers, and casts and peels on one roller. A blower is provided to face the belt from the one roller toward the other roller, and the drying wind is sent from the blower. A cooler is provided so as to face the belt that faces the peeling position from the other roller, and blows cooling air from the cooler to cool the cast film. In this way, in Japanese Patent Laid-Open No. 2006-306059, the flexible film on the belt is dried in an upstream region in the conveying path and cooled immediately before peeling. According to this method, the film excellent in the optical characteristic can be manufactured efficiently.

Moreover, the surface smoothness is calculated | required by the film used for optical uses, such as a polarizing plate. Various proposals are already made about the method of improving the surface smoothness. For example, Japanese Patent Laid-Open No. 2006-306055 discloses that a blower for drying the cast membrane is arranged on the conveying path of the cast membrane, and the time for passing the breeze zone until the cast membrane reaches the blower is 10 seconds or less. I'm suggesting how. In addition, Japanese Patent Laid-Open No. 2003-053750 discloses a solution forming method using a cooling gelation method, wherein the average drying rate from casting to peeling is higher than 300 mass% / min and lower than 1000 mass% / min. In order to achieve this average drying speed, Japanese Laid-Open Patent Publication No. 2003-053750 discloses, for example, drying the casting membrane with a wind of 0.5 m / sec or less for one second immediately after casting, and then rotating the drum serving as a support. The flexible membrane is dried with a wind velocity of 15 m / sec facing the direction.

In addition, the drying method of a casting film is described, for example in Unexamined-Japanese-Patent No. 2010-082993, The method of this Unexamined-Japanese-Patent No. 2010-082993 has a relative velocity with respect to a moving flexible membrane in a cooling gelation system. The flexible membrane is gelled with a wind of 5 m / sec or less, and the downstream of the gelled position advances drying of the flexible membrane at a higher wind speed than before gelation.

However, even if the methods of Japanese Patent Laid-Open No. 2000-239403 and Japanese Patent Laid-Open No. 2006-306059 are applied, workability cannot be reliably improved. Specifically, according to the method of Japanese Patent Laid-Open No. 2000-239403, the processing suitability may be relatively good, but in many cases it is very bad, and the method of Japanese Patent Laid-Open No. 2000-239403 does not reliably improve the processing suitability. . Moreover, also about the method of Unexamined-Japanese-Patent No. 2006-306059, processability differs with the film obtained, and it is hard to say that the method of Unexamined-Japanese-Patent No. 2006-306059 contributes to these improvement.

Therefore, the present applicant is a solution film forming method for improving the processability, the temperature of the flexible film is maintained until the peeling point so as not to be lower than {(gelling point of the dope) -3} ℃, the flexible film is such that the transfer of the wet film is possible A method of advancing drying of the flexible membrane to harden has already been proposed in Japanese Patent Application No. 2011-278053 (currently being published: Japanese Patent Laid-Open No. 2013-082192).

However, according to the method of Japanese Patent Application No. 2011-278053, the smoothness of the membrane surface of a flexible membrane may be lost. For this reason, it turned out that only one film surface of a film can provide only the smoothness which is inadequate for use for the precise coating use which requires high performance quality. As shown in FIG. 11, it turned out that the elongate recessed part 3 extended in the longitudinal direction Z1 of the film 2 generate | occur | produces in one film surface 2a. This recessed part 3 is a length (length in length direction Z1) LL of several cm, and width (length LW in width direction Z2) of several mm. The film surface 2a in which the recessed part 3 arises respond | corresponds to the exposed one film surface in a flexible film, ie, the surface on the opposite side to the surface which contact | connects a support body.

The recessed part 3 of such an aspect has not been confirmed until now, and it generate | occur | produced for the first time by the method of Unexamined-Japanese-Patent Application 2011-278053. The recessed part 3 of such an aspect cannot be improved by the method of Unexamined-Japanese-Patent No. 2006-306055, Unexamined-Japanese-Patent No. 2003-053750, and Unexamined-Japanese-Patent No. 2010-082993. The combination of the methods of Japanese Patent Application Laid-Open No. 2006-306055, Japanese Patent Application Laid-Open No. 2003-053750, and Japanese Patent Application Laid-Open No. 2010-082993 does not improve the smoothness of the film surface.

Therefore, an object of this invention is to provide the solution film forming method which improves the processability of a film and the smoothness of a film surface.

In order to solve the above problems, the solution film forming method of the present invention comprises a casting step, a temperature holding step, a pure air drying step, a peeling step, and a film drying step, and the thickness ranges from 25 µm to 40 µm. Prepare endogenous film. The casting step forms the casting film by continuously casting the dope in which the cellulose acylate is dissolved in the solvent on the support. The temperature holding step is maintained until the temperature of the cast film is peeled off from the support so as not to be lower than {(dope gel point TG) -3} 占 폚. The forward air drying step starts sending gas from the state in which the solvent residual ratio is 300 mass% or more with respect to the casting film, and advances drying of the casting film. The gas to be sent to the flexible membrane has a direction of flow within a range of greater than 0 degrees and 45 degrees or less with a direction perpendicular to the membrane surface of the flexible membrane, and the relative speed to the moving speed of the flexible membrane is 15 m / sec or more and 30 m / sec. It is sent to a casting film as a pure wind in the following ranges. The peeling step forms the wet film by peeling the cast film in the state where the solvent remains from the support. In the film drying step, the wet film is dried to obtain a film.

It is preferable to adjust the temperature of a cast film by controlling the temperature of a support body.

It is preferable that the temperature of the gas sent as pure wind exists in the range of 20 degreeC or more and 70 degrees C or less.

It is preferable to send a gas by the pure wind until the elastic modulus of the flexible film reaches 50 MPa, and then send the gas by counter-wind with respect to the flexible film after the elastic modulus becomes 50 MPa or more.

It is more preferable to suck the atmosphere around the flexible membrane by the suction part which is arrange | positioned downstream from the position where the elasticity modulus of a flexible membrane becomes 50 MPa or more, and draws the opening which draws the atmosphere around the flexible membrane toward the upstream side in the movement direction of a flexible membrane. Do.

Upstream of the suction part, it is preferable to form the film by drying the film surface of the flexible film by pure air.

According to the solution film forming method of the present invention, a film excellent in processability and smoothness of a film surface can be produced.

The above objects and advantages will be readily understood by those skilled in the art by reading the detailed description of the preferred embodiment with reference to the accompanying drawings.
1 is a schematic diagram of a solution film forming facility in accordance with the present invention.
2 is a partial cross-sectional view of the nozzle of the air supply unit.
3 is a graph showing the relationship between the processability and the orientation of the film.
4 is a graph showing the relationship between the degree of orientation and the temperature of the drum.
5 is a graph illustrating a method for obtaining a gel point.
6 is a partial cross-sectional side view showing the outline of the path control unit.
7 is a plan view schematically illustrating the path control unit.
8 is a partial cross-sectional view showing an outline of the flexible chamber.
9 is a graph showing the relationship between the viscosity of the dope and the temperature.
10 is a schematic view of the flexible chamber.
It is explanatory drawing about the film surface, (A) is a top view of a film, (B) is sectional drawing along the line (b)-(b) of (A).

EMBODIMENT OF THE INVENTION The solution film forming equipment which implements this invention is demonstrated, referring FIG. 1 and FIG. The solution film forming equipment 10 includes a wet film forming apparatus 17, a first tenter 18, a second tenter 19, a roller drying apparatus 22, and a winding device 24. The wet film forming apparatus 17 is for forming the wet film 16 from the dope 13 in which the cellulose acylate 11 is dissolved in the solvent 12. The solvent 12 is made into the organic solvent. The first tenter 18 supports drying of the formed wet film 16 by a supporting member (not shown), and transports the wet film 16 until it reaches a constant solvent residual ratio. It is to let. The second tenter 19 is for supporting the side of the wet film 16 with a supporting member (not shown) to further advance the drying while appropriately applying tension in the width direction. The roller drying apparatus 22 further advances drying while conveying the wet film 16 which passed through the 2nd tenter 19 to the roller 21, and makes it the film 23. FIG. The winding apparatus 24 is for winding up the dried film 23 in roll shape.

The solution film forming equipment 10 is provided with a wet film 16 and a transfer path between the second tenter 19 and the roller drying apparatus 22 and between the roller drying apparatus 22 and the winding apparatus 24. Although the slit device (not shown) which cut | disconnects each side end part with the film 23 is provided, illustration is abbreviate | omitted. Moreover, the solvent residual ratio is {(M1-M2) / M2} × when the mass of the cast film or the wet film is M1 (unit; g), and the mass of the film obtained by drying them is M2 (unit; g). It is a percentage obtained by 100 and is a value of a so-called dry weight standard.

The wet film forming apparatus 17 includes a drum 29 as a support, a casting die 31, and a first air supply unit 35. It is preferable that the wet film forming apparatus 17 further includes a suction unit 39, a path control unit 41, and a second air supply unit 135. The drum 29 has the rotating shaft 29b, and the rotating shaft 29b is being fixed to the center of the circular side surface. The rotary shaft 29b rotates in the circumferential direction by a drive unit (not shown), whereby the drum 29 rotates in the circumferential direction. By this rotation, the circumferential surface 29a becomes an endless flexible surface to which the dope 13 is flexible.

The drive part of the drum 29 has a controller (not shown) which controls the drive part so that the drum 29 may rotate at the desired speed.

Above the drum 29, the casting die 31 which flows out the dope 13 is provided. An outlet (not shown) of the flexible die 31 through which the dope 13 flows out is a slit shape extending in the longitudinal direction of the rotating shaft 29b so that the outlet faces the peripheral surface 29a of the drum 29. The flexible die 31 is disposed. The dope 13 is cast on the drum 29 by continuously flowing the dope 13 from the casting die 31 to the rotating drum 29. By this casting, the casting film 32 is formed on the peripheral surface 29a which is the casting surface of the drum 29. The dope 13 flows out from the casting die 31 so that the thickness of the film 23 obtained may be in the range of 25 micrometers or more and 40 micrometers or less. In addition, the longitudinal direction of the rotating shaft 29b is the depth direction of the paper surface of FIG.

Regarding the dope 13 from the casting die 31 to the drum 29, a decompression chamber 44 (see FIG. 8) is provided upstream in the rotational direction of the drum 29. Omit. The decompression chamber 44 sucks the atmosphere of the upstream area of the dope 13 which flowed out, and depressurizes this area. By the pressure reduction by the pressure reduction chamber 44, the shape of the dope 13 is stabilized.

A plurality of rollers 48 are provided at the connecting portion between the drum 29 of the wet film forming apparatus 17 and the first tenter 18. After the casting film 32 is hardened on the drum 29 to such an extent that conveyance by these rollers 48 is possible, it peels off from the drum 29 in the state containing a solvent.

The drum 29 has a temperature controller 34 that controls the temperature of the circumferential surface 29a. By controlling the temperature of the circumferential surface 29a by the temperature controller 34, the temperature of the flexible film 32 in contact with the circumferential surface 29a is controlled.

The first air supply part 35 is for supplying dry gas to the casting film 32. The first air supply unit 35 includes a duct 36, a blower 37, and a controller 38. The duct 36 has a duct main body 36a and the some nozzle 36b. The duct body 36a has a shape along the circumferential surface 29a of the drum 29 so as to cover the flexible film 32 passing therethrough, and is provided to face the circumferential surface 29a of the drum 29.

Each nozzle 36b protrudes and is provided in the opposing surface which opposes the circumferential surface 29a of the drum 29 of the duct main body 36a. Each nozzle 36b is a shape extended in the width direction of the drum 29 corresponding to the longitudinal direction of the rotating shaft 29b, ie, the width direction of the casting film 32, The some nozzle 36b has the circumferential direction of a drum. It is configured to be listed as. As shown in FIG. 2, the slit 36d is formed in the front-end | tip of the nozzle 36b which faces the circumferential surface 29a of the drum 29. As shown in FIG. This slit 36d is an opening extended in the width direction of the drum 29. Each slit 36d flows out the gas supplied to the duct main body 36a.

The duct body 36a is a flexible die 31 as far as possible in a range in which adverse effects on the dope 13 are not caused, such as the dope 13 coming out of the flexible die 31 by the gas discharged from the nozzle 36b. It is preferable to arrange close to). For example, the duct body 36a is disposed close to the casting die 31 so that the casting film 32 contacts the gas from the nozzle 36b in a state in which the casting film 32 has a solvent residual ratio of 300% by mass or more.

The nozzle 36b extends toward the downstream side in the rotational direction of the drum 29. Specifically, when the nozzle 36b is viewed from the side as shown in FIG. 2, the angle formed by the direction of the gas flowing out of the slit 36d and the direction perpendicular to the film surface of the flexible film 32 (hereinafter referred to as a blowing angle). The nozzle 36b extends toward the downstream side in the rotational direction of the drum 29 so that θ1 is larger than 0 ° and within a range of 45 ° or less. Thereby, the gas from the nozzle 36b is supplied as pure wind with respect to the casting film 32 which moves according to the rotation of the drum 29. As shown in FIG. The blowing angle θ1 is more preferably greater than 0 ° and in the range of 30 ° or less. In addition, in FIG. 2, the perpendicular | vertical line with respect to the film surface of the flexible film 32 is attached | subjected with the code | symbol L. As shown in FIG.

However, the direction of the gas which flows out from the nozzle 36b generally corresponds substantially to the direction in which the tip of the nozzle 36b faces. For this reason, in order to make blowing angle (theta) 1 into the said range, the front end of the nozzle 36b faces downstream in the rotational direction of the drum 29, and the direction which the front end faces is directed to the film surface of the flexible film 32. What is necessary is just to be in the range of larger than 0 degree and 45 degrees or less with respect to a perpendicular direction, and it is more preferable to set it in the range of larger than 0 degree and 30 degrees or less.

The blower 37 supplies gas to the duct body 36a. The controller 38 controls the temperature, humidity, and flow rate of the gas sent from the blower 37 to the duct body 36a. By this control, the temperature, humidity, flow rate and flow rate of the gas from the nozzle 36b are adjusted. For example, the gas of the blower 37 is heated by the controller 38, and the heated gas is sprayed on the flexible membrane 32 as warm air, thereby drying the flexible membrane 32, in particular, on the membrane surface of the flexible membrane 32. Proceed to drying. However, drying of the flexible membrane 32 can also be advanced by cooling the gas of the blower 37 with the controller 38, and spraying this cooled gas into the flexible membrane 32 as cold air.

It is preferable that the gas from the slit 36d is adjusted so that the speed with respect to the moving speed of the flexible film 32, ie, the relative speed, is within a range of 15 m / sec or more and 30 m / sec or less. Due to such a high speed pure wind, the film surface of the flexible film 32 is dried before the inside, and a smooth and dried film is quickly and reliably formed on the film surface of the flexible film 32. More preferably, the gas from the nozzle 36b is supplied to the flexible film 32 at a relative speed within a range of 15 m / sec or more and 30 m / sec, and at a relative speed within a range of 20 m / sec or more and 30 m / sec or less. It is more preferable to supply.

It is preferable that the temperature of the gas from the nozzle 36b exists in the range of 20 degreeC or more and 70 degrees C or less. As a result, a smooth and dried film is formed on the film surface of the cast film 32 more quickly and more reliably. As for the temperature of the gas from the nozzle 36b, it is more preferable to exist in the range of 25 degreeC or more and 60 degrees C or less, and it is more preferable that the temperature of the gas from the nozzle 36b exists in the range of 30 to 40 degreeC.

The duct 36 may be replaced with another blowing member. As another blowing member, for example, there are a plurality of blowing nozzles (not shown) in which openings are formed at the tip, and the tip is directed to the drum 29. In this case, the plurality of blow nozzles may be connected to the blower 37, and the gas guided by the blower 37 may be discharged from the openings of the respective tips. As another blowing member, there are, for example, blowing nozzles (not shown) and suction nozzles (not shown) arranged alternately in the rotational direction of the drum 29. The suction nozzle sucks gas, and in this case, the opening of the tip of the blowing nozzle is directed to the downstream side, and the tip of the suction nozzle is directed to the upstream side. By such a nozzle pair between the blowing nozzle and the suction nozzle, it is possible to reliably flow the gas from the blowing nozzle along the flexible membrane 32.

Moreover, in this embodiment, although the nozzle 36b uses the duct 36 which protruded toward the drum 29 from the lower surface of the duct main body 36a, you may replace it with another duct. As another duct, the nozzle (not shown) may have a shape extending from the lower surface of the duct body (not shown) into the duct body, that is, it is formed accommodated in the duct body.

As described above, in the case of using another duct instead of the duct 36, it is preferable that the nozzle be formed so that the gas flows out within a range in which the blowing angle θ1 is larger than 0 ° and is 45 ° or less.

The suction part 39 is for making the gas which flowed out from the nozzle 36b reliably flow along the conveyance path of the casting film 32. The suction part 39 is provided with the duct 40 and the suction device 42. The duct 40 is arrange | positioned downstream of the duct 36 in the rotation direction of the drum 29, and is provided opposite the circumferential surface 29a of the drum 29. As shown in FIG. The duct 40 extends in the width direction of the circumferential surface 29a to cover the entire width direction of the flexible film 32. The duct 40 is formed with an opening 40a for sucking in the atmosphere on the flexible film 32, and the duct 40 is disposed such that the opening 40a faces the upstream side in the rotational direction of the drum 29. do. The opening 40a extends in the width direction of the circumferential surface 29a. The aspirator 42 sucks gas, and by this suction, the atmosphere on the casting film 32 is sucked from the opening 40a. Thereby, the gas which flowed out from the nozzle 36b flows more reliably along the conveyance path of the casting film 32, and the dried film is formed faster and more reliably on the film surface of the casting film 32.

The 2nd air supply part 135 is for supplying gas so that it may become counterwind with respect to the casting film 32 toward the peeling position PP (refer FIG. 6). The second air supply part 135 is disposed downstream of the suction part 39. The second air supply unit 135 has a duct 136 and a blower 137 having the same configuration as the blower 37. The duct 136 has a duct body 136a through which the gas from the blower 137 is fed, and a nozzle 136b formed in the duct body 136a. The nozzle 136b has the same structure as the nozzle 36b, and the duct 136 is arrange | positioned so that the opening of the front end of the nozzle 136b may face an upstream side in the rotation direction of the drum 29. As shown in FIG. Thereby, the 2nd air supply part 135 sends the gas dried by counterwind with respect to the casting film 32. As shown in FIG.

The second air supply section 135 is operated when drying of the flexible film 32 by the first air supply section 35 is insufficient at the peeling position PP. Insufficient drying at the peeling position PP means that conveyance by the roller 48 of the wet film 16 formed by peeling is impossible or unstable. When the drying of the flexible membrane 32 is insufficient in this manner, the flexible membrane 32 is operated to the extent that the wet film 16 can be conveyed by operating the second air supply unit 135 and supplying gas to the flexible membrane 32. To dry. Therefore, when not operating the 2nd air supply part 135, the suction part 39 is arrange | positioned near the downstream side in the rotation direction of the drum 29, and arrange | positioned as close as possible to the 2nd air supply part 135. It is desirable to.

The elasticity modulus of the cast film 32 increases as drying advances. When gas is sent to the flexible membrane 32 by the 2nd air supply part 135, the duct 40 of the suction part 39 is arrange | positioned downstream from the position where the elasticity modulus of the flexible membrane 32 becomes 50 Mpa or more. In the case where the second air supply section 135 is operated, the duct 40 of the suction section 39 is sized to cover the entire width direction of the flexible membrane 32 passing therethrough, and thus acts as a switching member for switching the wind direction. do. As a result, in the upstream of the duct 40, forward wind is supplied to the flexible membrane 32 toward the peeling position PP, and inversely downstream of the duct 40. Thus, when the elasticity modulus of the flexible film 32 is 50 Mpa or more, it is preferable to change the direction of the gas supplied to the flexible film 32 from pure wind to reverse wind.

As mentioned above, in the upstream of the duct 40, the membrane surface of the flexible membrane 32 is rapidly dried compared with the inside by the pure wind of the said predetermined speed | rate, and the dried film is formed in the membrane surface of the flexible membrane 32. As shown in FIG. By contraction of this film, the flexible film 32 becomes a smooth surface. Moreover, since the flexible film 32 which passed through the duct 40 has a dried film, downstream of the duct 40, even if gas is sent by a backwind, the flexible film 32 does not generate | occur | produce the unevenness | corrugation in the film surface of the flexible film 32. Drying proceeds, and the peeled wet film 16 is stably conveyed by the roller 48.

When the rotational speed of the drum 29 is slowed down, the dope 13 is brought into contact with the peripheral surface 29a of the drum 29 to move from the flexible position PC to the peeling position PP where the flexible film 32 starts to form. Leading time to lengthen. If the casting time is long, only the gas supplied from the first air supply unit 35 causes the casting film 32 to be sufficiently dried to reach the peeling position PP. Therefore, when the rotational speed of the drum 29 is relatively slow, it is not necessary to operate the second air supply section 135. For example, when the film 23 whose thickness is 25 micrometers or more and 40 micrometers or less is manufactured using the drum 29 whose diameter of a circular cross section is about 3.5 m, the peripheral surface of the drum 29 ( If the speed of 29a) is less than 0.5 m / s, the second air supply section 135 may not be operated.

On the other hand, when the rotational speed of the drum 29 is relatively high, the casting time is shortened, and when the casting film 32 is insufficient in drying at the peeling position PP, in addition to the first air supply unit 35, the second The air supply unit 135 is operated. For example, when the film 23 whose thickness is 25 micrometers or more and 40 micrometers or less is manufactured using the drum 29 whose diameter of the circular cross section of the drum 29 is about 3.5 m, the drum 29 It is preferable to operate the 2nd air supply part 135 as the speed of the circumferential surface 29a of () is 0.5 m / s or more.

The elastic modulus of the flexible film 32 is made of a sample of the flexible film 32, and the sample is obtained by using a commercially available elastic modulus measuring instrument (e.g., 5582 type manufactured by Instron Co., Ltd.). The sample is made into a sheet shape, and the production conditions correspond to the gas supply conditions by the first air supply unit 35. Thereby, the position on the conveyance path of the flexible film 32 whose elasticity modulus becomes 50 Mpa is specified. The duct 40 of the suction part 39 may be arrange | positioned downstream from a specific position or this position.

Instead of the suction part 39, you may provide the windshield (not shown) arrange | positioned with respect to the circumferential surface 29a. The windshield preferably extends in the width direction of the circumferential surface 29a so as to block the flow of gas on the entire width region of the flexible membrane 32 passing therethrough. As a result, the windshield acts as a switching member for switching the wind direction.

Instead of the duct 36, when the blowing nozzles (not shown) and the suction nozzles (not shown) arranged alternately in the rotational direction of the drum 29 as described above are used, the blowing nozzles and the suction nozzles By arranging a plurality of nozzle pairs on the conveying path until reaching the duct 40, the suction part 39 and the above-mentioned windscreen do not need to be provided.

The wet film forming apparatus 17 includes a flexible chamber (casing) 45 surrounding the flexible die 31, the drum 29, the duct 36, and the path control unit 41. The blower 37, the controller 38, and the temperature controller 34 are preferably disposed outside the flexible chamber 45. The flexible chamber 45 includes an air supply / exhaust unit 88 (see FIG. 8), and the air supply / exhaust unit 88 supplies an air supply unit 91 (see FIG. 8) for supplying gas thereinto, and an internal gas. It has the exhaust part 92 (refer FIG. 8) discharged | emitted to the exterior. By this air supply / exhaust unit 88, the inside of the flexible chamber 45 is controlled by temperature, humidity, and solvent gas concentration to a predetermined range, respectively. Although the drying of the flexible membrane 32 advances to some extent according to this control, since it cannot be said that it is enough, it is preferable to use the 1st air supply part 35. FIG. However, the solvent gas means that the solvent 12 evaporates and becomes a gas.

As the temperature of the drum 29 is set higher, drying of the casting film 32 proceeds. In addition, depending on the type of the solvent 12, the casting film 32 may be easily evaporated, and drying of the casting film 32 may be easy. However, there is a limit to the amount of the solvent 12 to evaporate. Therefore, when evaporating more solvent, the 1st air supply part 35, the 1st air supply part 35 and the suction part 39, the 1st air supply part 35 and the 2nd air supply part 135, or Drying is promoted by the first air supply unit 35, the suction unit 39, and the second air supply unit 135.

The temperature of the flexible film 32 is not at all influenced by the gas caused by the first air supply unit 35 and the second air supply unit 135, but the temperature of the circumferential surface 29a of the drum 29 in contact with each other is not limited. The impact is very large. In addition, since the flexible film 32 is thin, when formed, the temperature of the flexible film 32 becomes substantially the same as the temperature of the circumferential surface 29a of the drum 29, and at the peeling position PP (refer FIG. 6). Until this, the temperature of the circumferential surface 29a of the drum 29 is maintained. That is, the temperature of the casting film 32 from the casting position PC to the peeling position PP is maintained at the same temperature as the circumferential surface 29a of the drum 29. For this reason, the temperature of the flexible film 32 may not be detected by the detection apparatus, and the set temperature of the peripheral surface 29a of the drum 29 may be regarded as the temperature of the flexible film 32. Therefore, the temperature control apparatus of the flexible film 32 is the drum 29 as a support body. The set temperature of the drum 29 will be described later with reference to other drawings.

At the time of peeling, as shown in FIG. 1, the wet film 16 is supported by the peeling roller (hereinafter referred to as peeling roller) 33, and the peeling position at which the flexible film 32 is peeled from the drum 29 ( PP) (refer FIG. 6) is kept constant.

The path control part 41 is provided upstream of the peeling roller 33, and is for controlling the path | route of the wet film 16 toward the peeling roller 33. As shown in FIG. The duct 136 of the 2nd air supply part 135 is arrange | positioned upstream of the path control part 41, and is near to the downstream side in the rotation direction of the drum 29 so that it may be as close as possible to the path control part 41. FIG. To place. The path control part 41 and the method of peeling the flexible film 32 from the drum 29 are mentioned later using another figure.

The wet film 16 formed by peeling is conveyed by the roller 48 and guided to the 1st tenter 18. As shown in FIG. In the first tenter 18, the side end portion of the wet film 16 is supported by a support member (not shown), and the wet film 16 is dried while being conveyed to the support member. The support member is a plurality of pins (not shown). The wet film 16 is supported by passing the pin through the side end portion of the wet film 16. The pin of each side end part moves to a conveyance direction, applying the tension | tensile_strength to the width direction of the wet film 16 suitably. The tension is set based on the optical performance (for example, retardation) of the film 23 to be manufactured. For example, in the case where the width of the wet film 16 is widened at a predetermined width enlargement ratio in order to express the desired optical performance on the film 23, the wet film 16 is in the width direction so as to have a predetermined width enlargement ratio. To give tension.

The second tenter 19 downstream of the first tenter 18 is also provided with a plurality of supporting members for supporting each side end of the wet film 16. This supporting member is a clip for holding the side end of the wet film 16. The plurality of clips impart a predetermined tension to the width direction of the wet film 16 at a predetermined timing. The tension given in the 2nd tenter 19 is also set based on the optical performance (for example, retardation) of the film 23 to be manufactured.

The 1st, 2nd tenters 18 and 19 all have the chamber (not shown) which surrounds a conveyance path. Ducts (not shown) are provided inside the chambers of the first and second tenters 18 and 19, respectively, and these ducts (not shown) face the conveying path of the wet film 16. A plurality of air supply nozzles (not shown) and suction nozzles (not shown) are respectively formed. By the delivery of the dry gas from the air supply nozzle and the suction of the gas from the suction nozzle, the interior of the chambers of the first and second tenters 18 and 19 is maintained at a constant humidity and solvent gas concentration. By passing through the inside of each chamber of the 1st, 2nd tenters 18 and 19, drying of the wet film 16 is advanced. In the first tenter 18, the wet film 16 is dried to such an extent that the clip of the second tenter 19 can be gripped. In contrast, in the second tenter 19, the degree of drying to be reached is determined in consideration of the timing of tension provision in the width direction.

In the slit device (not shown), the wet film 16 which passed through the 2nd tenter 19 removes each side end part with a support mark by a support member by continuously cutting with a cutting blade. The center part between one side end part and the other side end part is sent to the roller drying apparatus 22.

When the wet film 16 is sent to the roller drying apparatus 22, it is supported by the circumferential surface of the some roller 21 arrange | positioned in the conveyance direction. In these rollers 21, there exists a drive roller which rotates in a circumferential direction, and it is conveyed by rotation of this drive roller.

The roller drying apparatus 22 has a duct (not shown) which flows out the dried gas, and has a chamber (not shown) which partitions the space into which the dry body is supplied from the outside. The plurality of rollers 21 are housed in this chamber. A gas introduction port (not shown) and an exhaust port (not shown) are formed in the chamber of the roller drying apparatus 22, and the roller drying apparatus 22 is supplied by supplying a dry gas from the duct and exhausting from the exhaust port. The chamber's chamber is maintained at a constant humidity and solvent gas concentration. By passing through the chamber inside of the roller drying apparatus 22, the wet film 16 is dried to become a film 23.

The film 23 dried by the roller dryer 22 is removed by a slit device (not shown) by continuously cutting each side end portion with a cutting blade. The center part between one side end part and the other side end part is sent to the winding-up apparatus 24, and is wound up in roll shape.

In FIG. 1, the case where the drum 29 is used as a support body is shown. However, the support may be an annular belt (also referred to as a band, not shown) wound around the circumferential surface of a plurality of rollers (not shown). When the belt is used as the support, at least one of the plurality of rollers on which the belt is wound is a driving roller that rotates in the circumferential direction. By rotation of this drive roller, a belt is conveyed in a longitudinal direction and it circulates continuously.

When using a belt as a support body, the temperature of the circumferential surface can be adjusted with the roller by which the belt was wound, and what is necessary is just to control the temperature of a belt by this roller. As such, the support is not limited to the drum 29. However, the case where a belt is used is mentioned later using another figure.

The casting time from the casting position PC at which the dope 13 contacts the peripheral surface 29a of the drum 29 to start forming the casting film 32 from the casting position PC to the peeling position PP is determined by the drum ( Depends on the speed of rotation. For example, the greater the rotational speed of the drum 29, the shorter the casting time. In addition, since the size of the drum 29 is limited, the cast film conveying distance from the flexible position PC to the peeling position PP is extremely short compared with the belt. Therefore, when using the drum 29 as a support body, it is preferable to gelatinize by setting the temperature of the circumferential surface 29a which is a casting surface low, and cooling the casting film 32 actively. However, even if the flexible membrane 32 is cooled, the lower the temperature is, the better. The lower limit of the temperature and the setting method will be described later. On the other hand, when using a belt as a support body, the casting film conveyance distance from the casting position PC to the peeling position PP depends on the length of a belt. Therefore, for example, when using a short belt of less than 10 m as a support, gelation may be performed by setting the belt to a low temperature and actively cooling the cast film as in the case of using the drum 29. However, as described above, even if the flexible film 32 is cooled, the lower the temperature, the better. The lower limit of the temperature and the setting method will be described later.

On the other hand, when using a long belt of 10 m or more as a support, for example, the belt may be set to a high temperature, and the gel may be dried by drying the cast film. In the case where the temperature of the belt is set high in order to advance the drying, the flexible membrane is not actively and intentionally cooled because the emphasis is on increasing the drying rate of the flexible membrane (the amount of solvent evaporating from the flexible membrane per unit time). However, when manufacturing a cellulose acylate film, the temperature of a cast film becomes low compared with the dope 13 at the time of flowing out from the casting die 31 by the component of dope 13, etc. In this sense, even in the case of gelation by drying, as a result, the casting film has a lower temperature than the dope 13 at the time of outflow from the casting die 31.

The setting method of the temperature of the circumferential surface 29a of the drum 29 is demonstrated below using FIGS. The processability and the degree of orientation of the film are related to each other. First, the relationship between processability and the orientation degree of a film is calculated | required. In addition, the orientation degree here is the grade of the orientation in the direction along a film surface. This relationship may be shown, for example as a graph like FIG. In FIG. 3, the vertical axis | shaft is workability, and workability is so favorable that it goes downward. The horizontal axis is the degree of orientation, and the degree of orientation is higher toward the right side.

In FIG. 3, the curve A shown by a broken line and the curve B shown by a solid line are graphs regarding the films obtained from the dope 13 of the prescription which differs mutually on the same manufacturing conditions, respectively. Curve A and curve B differ from each other in the relationship between orientation and workability. In this way, the relationship between the orientation and the processability depends on the prescription of the dope 13. In either of curves A and B, the degree of orientation is higher as the workability is poor. Therefore, in order to raise workability, what is necessary is just to manufacture a film so that orientation degree may become lower.

However, when gelling by cooling, the casting film 32 is peeled from the drum 29 in a state where the solvent residual ratio is very high as compared with the case of gelling by drying. For this reason, when peeling the casting film 32 from the drum 29, there exists a tendency for the wet film 16 to expand | stretch larger in the conveyance direction of the wet film 16 corresponding to the peeling direction. Therefore, this elongation becomes one of the causes, and the film 23 obtained by gelling by cooling tends to show a high degree of orientation rather than the film 23 obtained by condensation by drying. However, the relationship between the workability and the degree of orientation is common, and the higher the degree of orientation, the worse the processability. Moreover, the relationship between processability and orientation degree has a correlation with prescription of dope 13, regardless of whether it cools and drys. For this reason, the relationship between workability and orientation degree is sufficient for every prescription of dope 13.

Here, the target processing level is MT, and the degree of orientation corresponding to the target level MT is obtained. Since the obtained orientation degree is an orientation degree corresponding to the target level MT of workability, this is called objective orientation degree PT after that. In order to achieve the target level MT of the workability, the film 23 is manufactured to have an orientation of less than or equal to the target orientation PT. Thus, the objective value of the orientation degree of the film 23 to manufacture is set from the level of the target processability. The target orientation in the curve A is PTa, and the target orientation in the curve B is PTb.

Moreover, the relationship between the temperature of the drum 29 and the orientation degree of the film obtained is calculated | required. This relationship may be shown, for example as a graph like FIG. In FIG. 4, the vertical axis | shaft is an orientation degree and the orientation degree is low, so that it goes down. The horizontal axis is the temperature of the support, and the higher the temperature is toward the right side. In FIG. 4, the case where the dope 13 which manufactures the film of the curve A of FIG. 3 is used is shown. However, the same tendency is obtained also when the dope 13 which manufactures the film of the curve B of FIG. 3 is used. That is, the relationship between the temperature of the drum 29 and the orientation degree of the film obtained becomes the same tendency regardless of the prescription of the dope 13 to be used.

As shown in FIG. 4, the higher the temperature of the drum 29 is, the lower the orientation degree of the film obtained. Therefore, in order to make orientation degree lower, what is necessary is just to manufacture the film 23 by making the temperature of the drum 29 higher, maintaining the temperature of the casting film 32 at a higher temperature. Moreover, with respect to the film obtained from the dope 13 of a certain prescription, as shown in FIG. 3, processability and an orientation degree correspond to 1 to 1, and as shown in FIG. 4, the orientation degree and the temperature of the drum 29 are It is one-to-one correspondence. Therefore, with respect to the film obtained from the dope 13 of a certain prescription, processability and the temperature of the drum 29 are one-to-one correspondence.

Here, the temperature of the circumferential surface 29a of the drum 29 corresponding to the target orientation degree PT is obtained. The temperature of the peripheral surface 29a of this drum 29 is set to T1. The higher the temperature of the circumferential surface 29a of the drum 29, the lower the orientation of the film obtained, so that the temperature of the circumferential surface 29a of the drum 29 is expressed from the viewpoint of developing an orientation of less than or equal to the target orientation PT. What is necessary is just T1 or more. Therefore, T1 becomes a lower limit of the temperature which should be set of the circumferential surface 29a of the drum 29. FIG. Therefore, the temperature T1 of the circumferential surface 29a of the drum 29 obtained as described above is referred to as the minimum set temperature. However, the upper limit value (hereinafter, referred to as the highest set temperature) of the set temperature of the peripheral surface 29a of the drum 29 is denoted by a symbol T2 in FIG. 4, and the maximum set temperature will be described later.

In this way, the lower limit of the set temperature of the circumferential surface 29a of the drum 29 is set from the target level of workability through the degree of orientation. In addition, as mentioned above, the temperature of the flexible film 32 and the temperature of the circumferential surface 29a of the drum 29 can be considered to be the same. Therefore, in order to manufacture the film 23 whose workability satisfies the target level MT, it is maintained so as not to be lower than T1 until the temperature of the flexible film 32 peels off (until the peeling position PP is reached). In order to do this, the temperature of the circumferential surface 29a of the drum 29 is made higher than or equal to the minimum set temperature T1. As a result, a film is produced whose processability satisfies the target level MT.

In addition, the gelation point TG with respect to the dope 13 of a certain prescription can be calculated | required by the following method. This method finds the gel point from the storage modulus (G ') and the loss modulus (G'), and has already been widely used as a method for obtaining the gel point. In FIG. 5, the vertical axis indicated by the solid line on the left is the storage modulus G ′, and the vertical axis indicated by the broken line on the right is the loss modulus G ′ ′. Any vertical axis shows a higher value as it goes upward. The horizontal axis is the temperature of the dope, and the higher the temperature is toward the right side. The method for calculating the storage modulus G 'and the loss modulus G' 'is not particularly limited and may be a known method. In the present embodiment, however, the storage modulus G 'and the loss modulus G' 'are determined by a viscoelasticity measuring device (model: MCR-300) manufactured by Physica.

In FIG. 5, the curve g1 shown by the solid line is a graph showing the relationship between the storage modulus G 'and the temperature of the dope 13, and the curve g2 shown by the broken line shows the loss modulus G' 'and the dope. It is a graph which shows the relationship with the temperature of (13). The storage modulus G 'and the loss modulus G' 'both decrease as the temperature of the dope 13 increases. Thus, the storage modulus G 'and the loss modulus G' 'of the dope 13 each have a dependency on temperature, that is, a temperature dependency. However, the storage modulus (G ') and the loss modulus (G' ') have different dependences on the temperature of the dope 13, and in a polymer solution such as the dope 13, an intersection exists when graphing both. do. The temperature indicating this intersection is the gelation point TG of the dope 13. As described above, the gelation point TG of the dope 13 is obtained from the intersection point when the storage modulus G 'and the loss modulus G' 'are graphed.

According to each relationship shown in FIG. 3, FIG. 4, etc., when the relationship between the minimum set temperature T1 calculated | required previously and the gel point TG (unit; degreeC) is calculated | required, the minimum set temperature T1 (unit; degreeC) will be And {(gel point (TG))-3} ° C. (T 1 = (TG-3) ° C.). Thus, since the minimum set temperature T1 coincides with the gel point TG for the dope of any given prescription, if the gel point TG is obtained, the peripheral surface of the drum 29 from the processing suitability through the degree of orientation is obtained. It is not necessary to determine the lower limit of the set temperature of (29a). That is, the set temperature of the circumferential surface 29a of the drum 29 may be {(gel point TG) -3} ° C. or more from the viewpoint of improving workability.

However, the relationship that the minimum set temperature T1 coincides with a temperature lower by 3 ° C than the gel point TG is for the film 23 having a thickness of 25 µm and 25 µm, for example, 40 µm or 60 µm, It is based on the objective level of the objective level MP of processability required in the present. In the future, there is a strong possibility that the required level of workability will be higher than the current level. In this case, what is necessary is just to calculate | require the temperature of the support body corresponding to the level of processability requested | required similarly through an orientation degree. When the level of required workability rises, the difference between the gel point TG (= TG-T1) and the minimum set temperature T1 of the support similarly determined through the degree of orientation becomes smaller than 3 ° C. For this reason, the set temperature of the peripheral surface 29a of the drum 29 becomes temperature higher than {(gel point TG) -3} degreeC. Moreover, although the thinnest thickness is currently 25 micrometers among the films currently requested | required, there exists a possibility that the thickness of a film required may become thinner in the future. As the thickness of the film becomes thinner, fine crystallization of the cellulose acylate molecule tends to proceed, and according to this tendency, the processability may be lowered. For this reason, when the film 23 thinner than 25 micrometers is manufactured and workability becomes low, the set temperature of the peripheral surface 29a of the drum 29 is less than {(gel point TG) -3} degreeC. It is good to make it higher temperature.

In view of the above-described setting method of the minimum set temperature T1 and improvement of workability, the temperature of the peripheral surface 29a of the drum 29 is set to {(gel point TG) -3} ° C. or more, Applicable to any solution film which gels and casts a casting film | membrane. Moreover, setting the circumferential surface 29a of the drum 29 and the belt temperature by setting the minimum set temperature T1 as described above, and making these temperatures above a constant temperature reliably improves the workability. . Moreover, according to these methods, since the film 23 to be manufactured does not affect the optical performance (for example, retardation) made into the objective, in the 1st tenter 18 or the 2nd tenter 19, Stretching or drying in the roller drying apparatus 22 may be performed without changing the conditions set so far.

However, in the case of gelation by cooling, the gelation is less likely to proceed as the temperature of the peripheral surface 29a of the drum 29 is set higher. Therefore, in the conventional cooling gelation method, it is common to focus on the efficiency of manufacture, and to cool a flexible film | membrane by setting the temperature of a support body in especially low temperature among the well-known temperature range of a support body. For example, in the cooling gelation method in which the cellulose acylate is cellulose triacetate (TAC), when the drum 29 having a flexible film conveying distance is about 10 m, the temperature of the peripheral surface 29a is cooled to about -10 ° C. do. By the way, the lower the temperature of the drum 29, the higher the degree of orientation and worsening the processability. Therefore, in the present invention, even if the drum 29 is actively cooled as in the case of gelation by cooling, The temperature is not lower than the minimum set temperature T1.

Therefore, in the case of actively cooling the drum 29 to achieve gelation by cooling, in order to harden the flexible film 32 to the extent that conveyance of the peeled wet film 16 is possible, that is, self-supportability is expressed, The casting film 32 is dried. That is, in order to express self-supportability, the casting film 32 is dried in addition to cooling. As described above, in the present invention, in the case of actively cooling the drum 29 including the viewpoint of production efficiency, the gelling effect due to cooling is lower than that in the conventional cooling gelation method by the lowest set temperature T1. As it loses, it replenishes the gelling effect by drying. In other words, the drying step of the casting membrane 32 is a step of gelling supplementation in which the cooling gelling effect (gelling action) is supplemented to solidify the casting membrane. However, even when the drum 29 as the support is replaced with the support by a belt having a flexible film conveying distance of, for example, 100 m, the belt is actively cooled, {(gel point TG) -3} ° C. At the above temperature, gelation does not progress to the extent that the flexible film 32 exhibits self-supportability. For this reason, the drying process for supplementing the gelling effect by cooling is performed. In addition, in this embodiment, drying which supplements a gelling effect is performed with respect to the casting | flow_spread film 32 cooled. That is, cooling and drying are performed in parallel.

However, if the solvent residual ratio at the time of peeling is too small, the tension of the wet film 16 required for peeling will be forced to be high. When the tension of the wet film 16 required for peeling is too high, the orientation degree may increase. Therefore, it is preferable to advance drying of the casting film 32 so that the solvent residual ratio at the time of peeling may not be less than 100%.

Drying of the casting film 32 advances by supply of gas by the 1st air supply part 35 first. The progress of drying of the casting film 32, that is, the drying speed, is adjusted by controlling the temperature, flow rate, and flow rate of the gas from the nozzle 36b of the duct 36 of the first air supply unit 35. In addition, as described above, by using the suction unit 39 or the second air supply unit 135 in addition to the first air supply unit 35, the drying speed is further increased.

Next, the maximum set temperature T2 (see FIG. 4) will be described. This highest set temperature T2 is significant in the case where importance is placed on manufacturing efficiency. The maximum set temperature T2 is {(dope gel point TG) + 3} 占 폚. Thereby, the film 23 is reliably manufactured at the manufacturing speed at the same level as the conventional cooling gelation method. That is, the temperature of the cast film 32 is set by setting the temperature of the circumferential surface 29a to be in the range of {(dope gel point TG) -3} ° C. or more and {(dope gel point TG) +3} ° C. or less. Is maintained in the range of {(dope gelation point (TG))-3} ° C or more {(dope gelation point (TG)) + 3} ° C or less until peeling. Thereby, the film which improved the processability is manufactured at the speed similar to the manufacturing speed of the conventional cooling gelation method. For example, when the casting film conveying distance is 10 m and the thickness of the film to be produced is 40 µm, the temperature of the peripheral surface 29a of the drum 29 is set to {(dope gel point TG) +3} ° C. or less. In this case, the film 23 is produced at a speed of approximately 80 m / min. The same applies to the case of using a belt instead of the drum 29. However, when the maximum set temperature is {(gel point TG) +3} ° C., the longer the flexible film conveying distance is, the faster the film 23 is produced. Moreover, manufacturing efficiency improves further by using the 2nd air supply part 135.

In addition, you may change said highest set temperature T2 to a higher temperature according to the prescription of the dope 13 and the manufacturing speed made into the objective as mentioned above.

As mentioned above, this invention is applicable as long as it is the solution film which gelatinizes and casts the casting film 32. Moreover, this invention is applicable also when using the drum 29 as a support body like this embodiment. When a drum manufactures a film with wider width, it can manufacture a larger thing more easily than manufacturing a wider belt. Therefore, the request for widening of the film 23 can be met.

In addition, this invention is applicable also when manufacturing the film 23 in the range whose thickness is 25 micrometers or more and 40 micrometers or less by sharing dope 13 from which prescription differs. In this case, the gelation point TG is obtained for the dope softened in contact with the drum 29, and the minimum setting temperature T1 or the maximum setting temperature T2 is obtained based on this gelation point TG.

The above method is particularly effective in producing a cellulose acylate film having a low in-plane retardation (Re) or a thickness direction retardation (Rth). This is because, in the case of a cellulose acylate film having a low Re or Rth, the influence of the smoothness of the film surface is particularly remarkable. Low Re or Rth means that Re is about 5 nm or less and Rth is about 50 nm or less. Thus, the cellulose acylate film with low Re and Rth is used for the polarizing plate arrange | positioned on the viewing side opposite to the light source side among a pair of polarizing plates in a liquid crystal display, for example, and a pair of protective film in this polarizing plate It is used as a protective film arrange | positioned at the visual recognition side opposite to the middle light source side.

As for the long film 23 obtained by continuous solution film forming like this embodiment, nx is a refractive index of the longitudinal direction of the film 23, ny is a refractive index of the width direction of the film 23, and nz is a film 23 Re and Rth are calculated | required with the following formula, respectively, when the refractive index of the thickness direction of d), and d is made into the thickness of the film 23. In this specification, the value of Re and Rth is calculated | required by KOBRA 21 ADH (made by Oji Scientific instruments).

Re = (ny-nx) × d

Rth = ((ny + nx) / 2-nz) × d

However, in order to improve processability more reliably or to improve more, it is preferable to peel the casting film 32 from the drum 29 by the following method.

The process of peeling is demonstrated concretely, referring FIG. 6 and FIG. In FIG. 6, FIG. 7, the arrow Z1 shows the conveyance direction of the wet film 16, and the arrow Z2 shows the width direction of the wet film 16. In FIG. However, the width direction of the circumferential surface 29a corresponds to the width direction Z2 of the wet film 16. 6 and 7 are schematic views, and the peeling roller 33 is drawn small with respect to the thickness of the wet film 16.

In the following description, the space on one film surface side peeled off from the drum 29 of the wet film 16 is referred to as the first space 51 and the space on the other film surface side is referred to as the second space 52. FIG. 7: is the figure which looked at the wet film 16 and the path control part 41 from the 1st space 51 side. The peeling roller 33 is arrange | positioned so that the longitudinal direction may correspond to the width direction of the circumferential surface of the drum 29. The peeling roller 33 is provided on the opposite side to the drum 29 with respect to the conveyance path of the wet film 16. That is, since the drum 29 is provided in the 1st space 51, the peeling roller 33 is provided in the 2nd space 52. As shown in FIG.

The peeling roller 33 is provided with the drive member 70 and the controller 71 which controls this drive member 70. The peeling roller 33 rotates in the circumferential direction by a predetermined rotational speed by the drive member 70. The controller 71 controls the drive member 70 so that the peeling roller 33 rotates at the set speed, when the signal of the rotational speed of the set peeling roller 33 is input.

The peeling roller 33 supports the wet film 16 which was guided by the circumferential surface, and rotates and conveys the wet film 16. As shown in FIG. The drum 29 and the peeling roller 33 are arrange | positioned so that the wet film 16 may be wound up to the peeling roller 33, and the conveyance path downstream of the peeling roller 33 is defined. In this way, the wet film 16 is wound around the peeling roller 33 and the wet film 16 is conveyed to the peeling roller 33, thereby peeling off the cast film 32 from the drum 29.

However, the peeling roller 33 may not necessarily be a driving roller, or may be a so-called driven roller driven by the circumferential surface contacting the wet film 16 being conveyed. In this case, another conveying apparatus is installed downstream of the peeling roller 33. And the wet film 16 is supported by the peeling roller 33, and the wet film 16 is conveyed by the conveying apparatus provided, and the casting film 32 is peeled from the drum 29. As shown in FIG.

The path control part 41 is provided in the 2nd space 52 between the drum 29 and the peeling roller 33, and controls so that the wet film 16 may be conveyed to the desired path | route, ie, the target path | route. do. The path controller 41 controls the chamber 55 for dividing the space to be decompressed from the external space, the pump 56 for sucking the atmosphere inside the chamber 55, and the suction force of the pump 56. 57 is provided. When the signal corresponding to the value of the set pressure in the inside of the chamber 55 is input, the controller 57 adjusts the suction force of the pump 56 so that it may become set pressure.

The chamber 55 includes a first member 61 for dividing the second space 52 to be reduced in pressure from the upstream outer space in the conveying direction Z1 of the wet film 16 and the downstream side. A second member 62 partitioning from the outer space, a third member 63 and a fourth member 64 partitioning from the outer space on each side of the width direction Z2, and a lower partition spaced from the outer space below. Five members 65 are provided. The 1st-5th members 61-65 are plate shape, and among these, the 1st-4th members 61-64 are arrange | positioned in the standing posture. In addition, in the chamber 55, a first opening 68 facing the wet film 16 is formed so as to be surrounded by the first to fourth members 61 to 64, and the outside of the chamber 55 is formed. Gas is sucked in from this first opening 68.

The first member 61 is disposed to face the drum 29 and has a curved surface along the circumferential surface 29a of the drum 29. The 1st member 61 is arrange | positioned so that the distance with the drum 29 may be 100 micrometers or more and 2500 micrometers or less in consideration of the thickness of the flexible film 32. As shown in FIG. 61U of upstream ends of the 1st member 61 in the conveyance direction Z1 is located upstream rather than the downstream end 29D of the drum 29. As shown in FIG.

The second member 62 is disposed to face the peeling roller 33 and has a curved surface along the circumferential surface of the peeling roller 33. The 2nd member 62 is arrange | positioned so that the distance with the peeling roller 33 may be 100 micrometers or more and 2500 micrometers or less. The downstream end 62D of the second member 62 in the conveyance direction Z1 is located downstream from the upstream end 33U of the peeling roller 33. In the second member 62, a second opening 69 through which gas inside the chamber 55 flows is formed. The second opening 69 is connected to the pump 56. In addition, in FIG. 7, illustration of the 2nd opening 69 is abbreviate | omitted in order to avoid the trouble of drawing.

When the wet film 16 is seen from above in FIG. 6, as shown in FIG. 7, the third member 63 and the fourth member 64 each have side edges of the wet film 16. It is arrange | positioned so that it may become outside rather than 16e). As a result, the wet film 16 until the path is stabilized does not strike the third member 63 and the fourth member 64. When the opposing surface of the third member 63 and the fourth member 64 that faces the wet film 16 is viewed from the side, in this embodiment, as shown in FIG. 6, the desired surface of the wet film 16 Although it is curved so as not to overlap with a path, it is not necessarily a curved surface.

The interior of the chamber 55 is depressurized by gas being sucked by the pump 56 through the second opening 69. When the inside of the chamber 55 is depressurized, the second space 52 between the drum 29 and the peeling roller 33 is also depressurized, so that the pressure is lower than that of the first space 51. Thereby, the wet film 16 toward the peeling roller 33 is pulled toward the chamber 55 side, and is converted from the straight path (symbol A shown by the broken line in FIG. 6) to the curved path (indicated by the solid line in FIG. 6). When changing a path | route and seeing from the side like FIG. 6, a conveyance path becomes a convex shape to the 2nd space 52 side. Thus, the path control part 41 is a suction unit which sucks the gas of the 2nd space 52 between the drum 29 and the peeling roller 33, and by this suction, the drum 29 and the peeling roller ( The 2nd space 52 between 33) is depressurized, and the conveyance path of the wet film 16 is made convex on the 2nd space 52 side.

By making the conveyance path of the wet film 16 into the convex shape to the 2nd space 52 side, the force applied to the wet film 16 in the longitudinal direction of the force applied to the wet film 16 for peeling is larger than before. By making it small in width, more force is used for peeling among the force provided. For this reason, the orientation in the direction along the film surface of the cellulose acylate which is a polymer of the wet film 16 is suppressed, and as a result, a processability is improved more reliably or it improves significantly.

In the conventional method, when the peeling force is excessively large, the wet film 16 may be cut at the time of peeling. In the case where the production speed is increased, the solvent residual ratio at the time of peeling is higher, so that the adhesion between the cast film 32 and the drum 29 is greater. Therefore, the faster the film forming speed is, the larger the peeling force is, so that the cutting is easier. On the other hand, according to the said method, since the force given for peeling under a fixed manufacturing speed can be made smaller, as a result, there also exists an effect that a manufacturing speed can be made larger. In addition, according to the above method, since the spraying of gas is not performed on the wet film 16 having a very high solvent residual ratio such as immediately after peeling, the smoothness of the film surface of the wet film 16 is maintained, Pollution caused by this can also be avoided.

By controlling the conveyance path of the wet film 16 toward the peeling roller 33 as described above, the tangent of the circumferential surface 29a of the drum 29 at the peeling position PP and the wet film 16 form. Angle (theta) 2 can be enlarged, and it becomes easy to suppress the force required for peeling low.

As for angle (theta) 2 which the tangent of the peripheral surface 29a of the drum 29 in the peeling position PP and the wet film 16 make, it is more preferable to set it as the range of 30 degrees or more and 80 degrees or less.

When the angle θ2 formed between the tangent of the circumferential surface 29a of the drum 29 at the peeling position PP and the wet film 16 is increased, the winding center angle θ3 relative to the peeling roller 33 is It becomes larger than the winding center angle which is the case of the linear path A. FIG. When winding center angle (theta) 3 is easy to maintain large, the shape of the conveyance path between the drum 29 and the peeling roller 33 will also be more easy to hold | maintain in convex shape.

In addition, the winding center angle (theta) 3 is a center angle in the linear form which consists of the winding area 72 which the wet film 16 wound on the peeling roller 33, and the cross section circular center of the peeling roller 33. As shown in FIG.

From the viewpoint of making the angle θ2 formed by the tangent of the circumferential surface 29a of the drum 29 at the peeling position PP and the wet film 16 and the winding center angle θ3 larger, As described above, it is more preferable that the peeling roller 33 be a driving roller instead of the driven roller. What is necessary is just to reduce the rotational speed of the peeling roller 33 used as a driving roller in the case of maintaining the shape of the conveyance path which made it convex on the 2nd space 52 side, or making it larger convex. Thus, the angle (theta) 2 which the tangent of the circumferential surface 29a of the drum 29 in the peeling position PP and the wet film 16 make, and the winding center angle (theta) 3 make the peeling roller 33 In addition to the method of making the conveying path of the wet film 16 directed only by suction by the chamber 55, it can be made larger by controlling the rotational speed of the drive roller by using the release roller 33 as the drive roller. .

In this embodiment, although the 2nd space 52 was depressurized so that the 2nd space 52 may be lower than the 1st space 51, this invention is not limited to this. For example, you may pressurize the 1st space 51 instead of the pressure reduction of the 2nd space 52, or in addition. However, this pressurization is pressurization by the static pressure, not pressurization by dynamic pressure.

The pressurization as the positive pressure causes the straight path A of the first space 51 and the wet film 16 to be separated from the chamber 29 so that the downstream portion of the drum 29 and the portion upstream of the peeling roller 33 are included. It is possible to carry out by repeating the feeding operation for feeding the gas into the chamber for a certain time and stopping operation for stopping the feeding operation for a certain time. According to this method, generation | occurrence | production of the dynamic pressure like injection of gas can be suppressed largely, and pressure can be applied to the wet film 16 from the 1st space 51 side. In addition, even in the case where the gap between the drum 29 and the peeling roller 33 is a very small gap of about several millimeters, according to this method, a pressure difference is reliably applied to the first space 51 and the second space 52. I can make it. Moreover, the smoothness of a film surface can be maintained more reliably than a gas is sucked in from a 2nd space side through the slit-shaped opening extended in the width direction Z2.

There is another method as a method for forming a pressure difference in the first space 51 and the second space 52 up to the drum 29 and the peeling roller 33. For example, a wet film forming apparatus without using the chamber 55 or the chamber (not shown) for pressurization surrounding the straight path A of the first space 51 and the wet film 16. In the chamber (not shown) which comprises (17) (refer FIG. 1), the partition member which partitions an internal space is provided, and there exists a method of making the pressure difference. By controlling the pressure of each space formed by the partition member, the pressure difference can be made to the 1st space 51 and the 2nd space 52 below from the conveyance path of the wet film 16, respectively. However, the chamber (not shown) constituting the wet film forming apparatus 17 covers the drum 29, the flexible die 31, the duct 36, and the peeling roller 33 so as to be partitioned from the external space. It can be formed. When the distance between the drum 29 and the peeling roller 33 is 5000 micrometers or more, it is more preferable to make the pressure difference using the chamber 55, and when it is less than 5000 micrometers, the chamber 55 and the 1st space A chamber (not shown) constituting the wet film forming apparatus 17 is used as a partition member without using the chamber (not shown) surrounding the straight path A of the 51 and the wet film 16. It may be a method of dividing the pressure difference.

The difference in pressure between the first space 51 and the second space 52 is determined by the wet film 16 from the peeling position PP until it passes through the winding area 72 of the peeling roller 33. It is preferable to determine based on solvent residual rate. It is preferable to make a conveyance path larger and convex by increasing a pressure difference, so that a solvent residual rate is large. This is because the greater the solvent residual ratio, the stronger the adhesion between the drum 29 and the cast film 32, and the easier the wet film 16 is to break.

The peeling position PP is formed in the downstream side in the rotational direction of the drum 29 so that it may go toward the center in the width direction Z2. For this reason, the force applied in the longitudinal direction of the wet film 16 at the time of peeling becomes large toward the center in the width direction Z2, and surface orientation becomes large. Therefore, in the peeling position PP, it is more preferable to make the pressure of the 2nd space 52 lower as it goes to the center. Thereby, the film 23 whose surface orientation is constant in the width direction Z2 can be manufactured. In order for the pressure of the second space 52 to be lowered toward the center at the peeling position PP, for example, an independent chamber (not shown) is further provided inside the chamber 55. There is a method of independently controlling each internal pressure between the chamber and the chamber 55. In other words, the pressure in the chamber (not shown) provided in the chamber 55 is lower than the pressure in the chamber 55.

The film 23 obtained by the above method satisfies the practical level sufficiently for the uniformity of the thickness. However, in the future, there is a possibility that further improvement in thickness uniformity may be required depending on the use or the like. What is necessary is just to perform the following method in order to improve the thickness uniformity of the film 23 further. However, the following method can be performed even when the path control part 41 is not arrange | positioned, and only one solution film and a tenter which do not hold | maintain the temperature of a flexible film to (TG-3) degreeC or more are used. It is also applicable to other well-known solution films, such as a solution film not used and a solution film using a belt instead of the drum 29 as the flexible support.

As shown in FIG. 8, the flexible die 31, the drum 29, the duct 36, and the path control part 41 are accommodated in the flexible chamber 45. As shown in FIG. The above-mentioned pressure reduction chamber 44 is arrange | positioned at the upstream of the casting die 31 in the rotation direction of the drum 29, and this pressure reduction chamber 44 is also accommodated in the casting chamber 45. As shown in FIG.

The flexible chamber 45 is provided with the 1st sealing member 81 between the flexible die 31 and the duct 36, and the 2nd sealing member 82 between the peeling roller 33 and the pressure reduction chamber 44. As shown in FIG. ). The first seal member 81 and the second seal member 82 are provided on the inner wall of the flexible chamber 45 in an upright position toward the drum 29. By the first seal member 81 and the second seal member 82, the inside of the flexible chamber 45 includes a first area 83 including a flexible die 31 and a pressure reducing chamber 44, and a duct ( 36 and the second area 84 including the peeling roller 33. However, a slight gap considering the thickness of the flexible film 32 between the tip of the first seal member 81 and the drum 29 so that the flexible film 32 passing through and the first seal member 81 do not contact each other. Is formed. In addition, a slight gap is formed between the tip of the second seal member 82 and the drum 29 so that the drum 29 and the second seal member 82 do not contact each other.

In the present embodiment, the flexible chamber 45 is divided into two areas of the first area 83 and the second area 84. However, the sealing member (not shown) which is the same as the first sealing member 81 or the second sealing member 82 in the second area 84 in accordance with the purpose of adjusting the speed of cooling or drying the flexible film 32 or the like. ) May be further provided to divide the second area 84 into more areas.

The first seal member 81 has a partition plate 81a and a labyrinth seal 81b, and the second seal member 82 has a partition plate 82a and a labyrinth seal 82b. The partition plate 81a and the partition plate 82a are respectively attached to the inner wall of the flexible chamber 45, and are extended in the upright position toward the drum 29. As shown in FIG. The labyrinth seal 81b is attached to the front end of the drum 29 side of the partition plate 81a, and the labyrinth seal 82b is attached to the front end of the drum 29 side of the partition plate 82a.

The flexible chamber 45 is provided with the viscosity control apparatus 87 connected to the 1st area 83, and the air supply / exhaust unit 88 connected to the 2nd area 84. As shown in FIG.

The air supply / exhaust unit 88 includes an air supply unit 91, an exhaust unit 92, and a control unit 93. The air supply unit 91 supplies gas to the second area 84. The exhaust unit 92 discharges the gas of the second area 84 to the outside. The control unit 93 controls the air supply unit 91 and the exhaust unit 92. For example, the control unit 93 controls the on / off of the air supply by the air supply unit 91, the air supply flow rate, the temperature, humidity, and solvent gas concentration of the gas to be sent out, and thus the gas suction by the exhaust unit 92. Control on / off and exhaust flow rate. By this supply / exhaust unit 88, the temperature, humidity, and solvent gas concentration of the second area 84 are respectively controlled in a predetermined range.

The viscosity control device 87 has a viscosity calculation unit 95 and a temperature control unit 96. The viscosity calculation unit 95 includes a flow meter 97, a detection unit 98, and a viscosity calculation unit 99.

The flowmeter 97 is provided in the piping upstream of the flexible die 31 to measure and output the flow rate of the dope 13. The detection part 98 is provided in the piping between the flowmeter 97 and the flexible die 31. As shown in FIG. The position of the detection part 98 may be upstream of the flowmeter 97. The pressure loss of the dope 13 from the casting die 31 toward the drum 29 is detected. Specifically, the detection unit 98 detects the pressure of the dope 13 guided to the casting die 31, and detects the pressure loss from the detected value and the pressure of the dope 13 flowing out of the casting die 31. Calculate and output However, the pressure of the dope 13 which flowed out from the casting die 31 does not need to be measured, and atmospheric pressure may be regarded as the pressure value of the dope 13 which flowed out from the casting die 31.

As for the viscosity calculation part 99, the input side is connected to the flowmeter 97 and the detection part 98, and the output side is connected to the temperature calculation part 101 of the temperature control unit 96. When the flow rate of the dope 13, the pressure loss in the casting die 31, and the flow path shape parameter of the casting die 31 which flows out the dope 13 are input, the viscosity calculation part 99 receives these input signals. Based on this, the viscosity of the dope 13 is calculated and output. A viscosity is computed by the following formula (1) well-known. In this way, the viscosity calculating unit 95 calculates the viscosity from the pressure loss with respect to the dope 13 flowing out from the casting die 31.

In the following formula (1), Q is the flow rate of the dope 13 (unit: mm ³ / s), ΔP is the pressure loss in the casting die 31, h, L and W is the dope (13) ) Is a flow path shape parameter of the flexible die 31 which flows out. h is the space | interval (unit: mm) of the clearance gap in the slit-shaped outlet of the casting die 31, and when the outlet is rectangular, the length of a short side corresponds to this. η is the viscosity (unit; Pa · s). L is the plate length in mm. The flow path of the dope 13 in the casting die 31 is a block (not shown) and an upstream block (not shown) and the downstream block (not shown) in the rotation direction of the drum 29 as well known, It is formed by enclosing the side plate arrange | positioned at each side part of these blocks. The width | variety of the flow path (length in the width direction of a drum) is constant in the fixed range from the outlet to the flow direction upstream of the dope 13 in the casting die 31. As shown in FIG. The length in the flow direction of the dope 13 of this flow path of fixed width corresponds to L. FIG. W is the length (unit: mm) of the gap in the slit-shaped outlet of the casting die 31, and when the outlet is rectangular, the length of a long side corresponds to this.

ΔP = 12? LQ / Wh ³ ... (One)

The viscosity of the dope 13 which flows out from the casting die 31 can also be calculated | required by another well-known method. In the case of obtaining the viscosity by another known method, there is a constant correlation between the viscosity by the other method to be used and the viscosity by the above method, so that the viscosity of the other method to be used and the viscosity by the above method may be corresponded. However, in the solution film which casts the dope 13, since high shear is applied with respect to the dope 13 in the casting die 31, viscosity is calculated | required by said method from a viewpoint of controlling a viscosity more precisely. It is preferable.

The temperature control unit 96 includes a temperature calculating unit 101, a control unit 102, and an air supply unit 103. The temperature control unit 96 may be provided with the exhaust part 104. When temperature and a flow volume are input, the air supply part 103 outflows the gas of the input temperature, for example, air at the input flow volume. When the flow rate is input, the exhaust part 104 sucks gas at the input flow rate and discharges it to the outside.

The control unit 102 is connected to the air supply unit 103 and the flexible die 31. When the temperature of the dope 13 made into the objective (henceforth dope object temperature) is input, the control part 102 calculates the temperature and flow volume of the gas which should flow out from the air supply part 103, and supplies the air supply part 103. ) To control the air supply unit 103. The flexible die 31 is provided with a temperature regulator (not shown) for adjusting the temperature of the flow path of the dope 13 formed in the inside, and when the dope target temperature is input, the control part 102 will receive a flexible die ( The set temperature of 31 is calculated, and the set temperature of the flexible die 31 is output to the temperature controller of the flexible die 31 to control the temperature regulator.

If there is an exhaust section 104, the control unit 102 also connects to the exhaust section 104. When the dope target temperature is input, the control unit 102 calculates the flow rate of the gas to be sucked by the exhaust unit 104, outputs the result to the exhaust unit 104, and controls the exhaust unit 104.

The temperature calculation unit 101 has an input side connected to the viscosity calculation unit 99 of the viscosity calculation unit 95 and an output side connected to the control unit 102. In the temperature calculation part 101, the relationship between the viscosity and temperature for every prescription of the dope 13 is input. When the viscosity of the dope 13 is input, the temperature calculation part 101 determines whether this viscosity is a range of 7 Pa * s or more and 9 Pa * s or less. When the viscosity is in the range of 7 Pa · s or more and 9 Pa · s or less, the dope target temperature is not output to the control unit 102, but when the viscosity is less than 7 Pa · s or larger than 9 Pa · s, the control unit 102 Output the dope target temperature. The detail of the output of the dope target temperature in the temperature calculation part 101 is mentioned later using another figure.

The viscosity control apparatus 87 of the said structure controls the temperature of the dope 13 cast by the drum 29 as follows. First, the flowmeter 97 of the viscosity calculation unit 95 measures the flow rate of the dope 13 which faces the casting die 31, and outputs it to the viscosity calculation part 99. FIG. The detection unit 98 detects the pressure loss of the dope 13 from the casting die 31 toward the drum 29 and outputs it to the viscosity calculation unit 99. The viscosity calculation unit 99 is a flow rate of the dope 13 guided to the casting die 31, the pressure loss in the casting die 31, and the flow path shape parameter of the casting die 31 flowing out the dope 13 Is input, the viscosity of the dope 13 from the casting die 31 toward the drum 29 is calculated from these input signals. The viscosity calculation unit 99 outputs the calculation signal to the temperature calculation unit 101 of the temperature control unit 96.

In the temperature calculation unit 101, the relationship between the viscosity of the dope 13 and the temperature is input in advance. The temperature calculation part 101 specifies the temperature range of the dope 13 corresponding to a predetermined viscosity range based on this relationship. When the calculation signal of the viscosity calculation part 99 is input, the temperature calculation part 101 determines whether the viscosity of the dope 13 corresponding to this calculation signal is a predetermined viscosity range. When it is determined that the viscosity is larger than the upper limit of the predetermined viscosity range, first, the temperature extracted from the temperature range of the dope specified is output to the control unit 102 as the dope target temperature. When it is determined that the viscosity is a predetermined temperature range, the temperature calculation unit 101 does not output to the control unit 102.

When the dope target temperature is input, the control unit 102 calculates the temperature and flow rate of the gas to flow out of the air supply unit 103, and outputs it to the air supply unit 103. The air supply unit 103 adjusts the temperature of the gas to the input temperature, and supplies the temperature adjusted gas to the first area 83 at the input flow rate. By this supply, the temperature of the first area 83 is adjusted. The temperature of the dope 13 out of the casting die 31 is influenced by the temperature of the atmosphere. For example, when the dope 13 comes out of the casting die 31, it may become substantially equal to the ambient temperature, and in this case, what is necessary is just to make the temperature of the 1st area 83 into the dope objective temperature. When making the temperature of the 1st area 83 into the dope object temperature, the control part 102 calculates the temperature of the gas which should flow out from the air supply part 103, for example to the same temperature as the dope object temperature.

When the dope target temperature is input, the control unit 102 calculates the set temperature of the flexible die 31 and outputs it to the temperature controller of the flexible die 31. The temperature controller adjusts the temperature of the flexible die 31 to be the input set temperature. By adjusting the temperature of the flexible die 31, the temperature of the dope 13 is adjusted while passing through the internal flow path. The control unit calculates the set temperature of the flexible die 31 to the same temperature as the dope target temperature, for example.

In this embodiment, by adjusting the temperature of both the 1st area 83 and the casting die 31, the temperature of the dope 13 is precisely adjusted so that it may become a dope object temperature. However, in the case where the temperature of the dope 13 is adjusted to be the dope target temperature by any one of the first area 83 and the flexible die 31, the temperature adjustment of any one may be sufficient.

However, the temperature of the dope 13 can be adjusted also by injecting the temperature-regulated gas into the dope 13 which flowed out from the casting die 31. FIG. However, in this method, the shape of the dope 13 which flowed out from the casting die 31 is disturbed by the dynamic pressure by the injection of gas, and the casting film 32 often does not smooth the membrane surface. Not. On the other hand, according to this embodiment which temperature-adjusts the whole atmosphere of the 1st area 83 by gas supply from the air supply part 103 to the 1st area 83, the pressure applied to the casting film 32 is dynamic pressure. Since the pressure is not static, the shape of the dope 13 flowing out from the casting die 31 is not disturbed, which is preferable.

When the exhaust part 104 exists, the control part 102 calculates the flow volume of the gas which should be attracted to the exhaust part 104, and outputs it to the exhaust part 104, when a dope target temperature is input. The exhaust unit 104 sucks the atmosphere of the first area 83 at the input flow rate. By this suction, the temperature of the first area 83 is adjusted more quickly.

The temperature of the dope 13 which is flexible to the drum 29 is adjusted to the dope objective temperature as mentioned above, and the viscosity is controlled in a predetermined range by this. The predetermined viscosity range is a viscosity range of 7 Pa · s or more and 9 Pa · s or less. When the viscosity is 7 Pa · s or more, the uniformity of the thickness of the film is very excellent as compared with less than 7 Pa · s. In addition, when the viscosity is larger than 9 Pa · s, the film surface of the film 23 often becomes a rough (sharkskin) shape, but the sharkskin is reliably prevented by setting the viscosity to 9 Pa · s or less.

The calculation method of the dope target temperature by the temperature calculation part 101 is demonstrated, referring FIG. In FIG. 9, the vertical axis | shaft is the temperature of the dope 13, and it means that temperature is higher so that it may be upward. The horizontal axis is the viscosity (unit: Pa · s) of the dope 13.

The curve A shown by a broken line and the curve B shown by a solid line are graphs which show the relationship between the temperature and viscosity which were respectively obtained about the dope 13 of the prescription which mutually differs. The relationship between the temperature and the viscosity is input to the temperature calculating section 101 in advance. Curve A and curve B differ from each other in the relationship between temperature and a viscosity. In this way, the relationship between the temperature and the viscosity depends on the prescription of the dope 13. Therefore, for each prescription of the dope 13, the relationship between temperature and viscosity is calculated | required, and the calculated relationship is input into the temperature calculation part 101, respectively.

The temperature calculation part 101 specifies the temperature of the dope 13 corresponding to the predetermined temperature range that the viscosity of the dope 13 is 7 Pa * s or more and 9 Pa * s or less. For example, about the curve A of FIG. 9, the temperature of the dope 13 whose viscosity is 7 Pa.s is specified, this is set to TA7 (degreeC), and the temperature of the dope 13 whose viscosity is 9 Pa.s. Is specified and this is set to TA9 (° C). As shown in FIG. 9, since the viscosity of dope 13 is so high that temperature is low, the viscosity of dope 13 corresponds to the predetermined temperature range that the viscosity of dope 13 is 7 Pa * s or more and 9 Pa * s or less. The temperature range is specified in the range of TA9 (° C) or more and TA7 (° C) or less. Thus, when the temperature corresponding to each of the lower limit and the upper limit of the predetermined viscosity range is specified, the temperature range corresponding to the predetermined viscosity range is specified. In FIG. 9, the code | symbol TAR is attached | subjected to the specified temperature range with respect to the dope 13 of the curve A. In FIG.

The temperature calculation unit 101 extracts one temperature from a specific temperature range TAR, and outputs the extracted temperature as the dope target temperature. The temperature to extract is not specifically limited, What is necessary is just arbitrary. However, the closer the viscosity is to 9 Pa · s, the more the thickness of the film 23 tends to be more uniform. Therefore, in consideration of this tendency, the temperature calculation section (1) to extract the temperature (TA9 (° C.)) corresponding to 9 Pa · s is considered. The output of 101) can be controlled. However, when the mass ratio of the solvent 12 in the dope 13 is very high, the temperature at which a viscosity becomes 9 Pa.s is too low, and a limit may arise in a manufacturing speed. In such a case, the output of the temperature calculating section 101 may be controlled so as to extract the temperature at which the viscosity is lower than 9 Pa · s in preference to the manufacturing speed or the like.

Also in the case of the dope 13 of the curve B, the dope target temperature is output similarly to the case of the dope 13 of the curve A mentioned above. That is, it is as follows. First, the temperature of the dope 13 whose viscosity is 7 Pa.s is specified, this is TB7 (degreeC), the temperature of the dope 13 whose viscosity is 9 Pa.s is specified, and this is TB9 (degreeC). Thereby, the temperature range of the dope 13 corresponding to the predetermined temperature range whose viscosity of the dope 13 is 7 Pa * s or more and 9 Pa * s or less is specified in the range of TB9 (degreeC) or more and TB7 (degreeC) or less. In FIG. 9, the code | symbol TBR is attached | subjected to the specified temperature range with respect to the dope 13 of the curve B. In FIG. The temperature calculation unit 101 extracts one temperature from a specific temperature range TBR and outputs the extracted temperature as the dope target temperature.

In order to make the thickness of the film 23 more uniform, the thickness of the cast film 32 is made more uniform. Conventionally, in order to make the thickness of a cast film more uniform, the method of making the viscosity of dope lower and thereby making the height of one film surface to which a cast film exposed is constant (leveling) is used. In addition, conventionally, in order to lower the viscosity of the dope, the mass ratio of the solvent in the dope is increased in a range where excessive load is not applied in the drying step of drying the wet film (to lower the mass ratio of solid content). ) There were many cases. Moreover, the temperature of the flexible dope has been conventionally set to the comparatively high temperature of the grade which the solvent contained in dope does not evaporate rapidly. For example, in the case of dope of the cellulose acylate which uses dichloromethane as one component of a solvent, the dope made into the temperature of about 35 degreeC was flexible. In contrast, in the present invention, the viscosity of the dope 13 is set to a range of 7 Pa · s or more and 9 Pa · s or less than conventionally. And control of a viscosity is performed by adjusting the temperature of dope 13, without changing the mass ratio of the solvent 12 (refer FIG. 1) in dope 13. For this reason, temperature adjustment of the dope 13 is performed for viscosity control, and the temperature of the dope 13 is set very much lower than before.

According to the above method, even if the prescription of dope 13 is not changed, the uniformity of the thickness of the film 23 improves more. For example, in order to smooth the exposed membrane surface of a flexible membrane, the conventional method which raises the mass ratio of the solvent in dope further does not need to be used by said method. For this reason, there is no need to change the conditions of the post-process according to the change of prescription of the dope 13, and there is no fear of lowering a manufacturing speed. The conditions of the post-process are, for example, blowing conditions in the duct 36 and blowing conditions and stretching conditions in the first tenter 18. Moreover, since the temperature of the dope 13 can be easily adjusted by said method irrespective of the prescription of dope, a viscosity is controlled easily. Moreover, in the said method, since the viscosity is set to said predetermined range higher than the conventional, the temperature of dope is adjusted to be lower than conventional. For this reason, it is not necessary to be concerned about foaming of the dope 13 and the casting film 32 by the rapid evaporation of the solvent 12. FIG.

As described above, a belt may be used instead of the drum 29 (see FIG. 1) as the support. An example in the case of using a belt is demonstrated referring FIG. In addition, in FIG. 10, the same code | symbol is attached | subjected about the apparatus, member, etc. which are the same as FIG. 1, FIG. 2, FIG. 8, and description is abbreviate | omitted. In the flexible chamber 45, a belt 105 as a support, rotating rollers 106 and 107, a duct 111, a duct 40, and a temperature control device 113 are housed. The flexible chamber 45 has the temperature control installation 110 which adjusts internal temperature.

The rotary roller 107 is a drive roller which rotates in a circumferential direction. The belt 105 is wound on the circumferential surfaces of the rotary rollers 106 and 107, is conveyed in the longitudinal direction by the rotation of the rotary roller 107, and continuously rotates.

Inside the rotary rollers 106 and 107, flow paths through which the heat transfer medium flows are formed, and the temperatures of the peripheral surfaces 106a and 107a of the rotation rollers 106 and 107 are sent by sending the heat transfer medium with temperature adjustment to the flow paths. Is controlled. The belt 105 is in contact with the circumferential surfaces of the rotary rollers 106 and 107 and is temperature controlled by this contact.

On the surface 105a facing the outer side of the belt 105 to be circumscribed, the dope 13 is flexible, and the flexible film 32 is formed. A temperature regulating device 113 is provided opposite to the back surface of the belt 105 (the belt surface opposite to the belt surface 105a) 105b. This temperature control apparatus 113 is equipped with the temperature control mechanism of heat_generation | fever and cooling. The temperature of the band 105 from one side of the rotary roller 106 and the rotary roller 107 to the other passes through the vicinity of the temperature regulating device 113. Thus, the band 105 is temperature-controlled by the rotating rollers 106 and 107 and the temperature control apparatus 113, and the temperature of the flexible film 32 is controlled by this temperature adjustment.

The duct 111 is used instead of the duct 36 and is connected to the blower 37 (refer FIG. 1). The duct 111 is provided with the duct main body 111a and the nozzle 111b. The duct body 111a is disposed to face the conveying path of the belt 105 that faces the rotary roller 106 from the rotary roller 107 facing the flexible die 31. The opposing surface of the duct 111 that faces the belt 105 is formed to be substantially parallel to the conveying path of the belt 105, and a nozzle 111b is formed on the opposing surface.

The duct 40 is disposed on the rotary roller 106. The duct 40 is arrange | positioned so that the opening 40a may face the upstream side in the conveyance direction of the belt 105. FIG.

The flexible chamber 45 may be connected to the second tenter 19 without passing through the first tenter 18. That is, when using the belt 105 as a support body, the 1st tenter 18 does not need to be installed in solution film forming equipment (not shown).

Below, the Example as this invention and the comparative example with respect to this invention are described.

[Example 1]

Using the solution film forming facility 10 shown in FIG. 1, the film 23 whose thickness is 40 micrometers was manufactured from the dope 13 of the following prescription. However, in this embodiment, the viscosity calculation unit 95 disposed in the solution film forming facility 10, the temperature calculation unit 101 of the temperature control unit 96, and the second air supply unit 135 are not used. Did. In the flexible chamber 45, the suction part 39 was not provided and the above-mentioned windscreen used instead of the suction part 39 was not provided. 35 degreeC was input into the control part 102 as the dope object temperature, and the temperature of the dope 13 which flows out from the casting die 31 was adjusted so that it might become equal to the dope object temperature. Therefore, the temperature of the flexible dope 13 (dope 13 at the time of flowing out from the flexible die 31) is 35 degreeC. Gel point TG of the dope 13 was 6 degreeC.

<Prescription of dope 13>

Solid ingredients ... Mass ratio in dope 13 is 20 mass%

Solvent… It is a mixture of dichloromethane and alcohol, and the volume ratio is dichloromethane: alcohol = 80: 20

Said solid component is TAC as the cellulose acylate 11, a plasticizer, a mat agent, and an ultraviolet (UV) absorber. The composition of a solid component is as follows specifically, TTP and BDP are a plasticizer and the silica particle of a silica particle dispersion liquid is a mat agent.

100 parts by mass of TAC (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

7.8 parts by mass of triphenyl phosphate (TTP)

3.9 parts by mass of biphenyl diphenyl phosphate (BDP)

1.6 parts by mass of an ultraviolet absorber (UV-1) (represented by Chemical Formula (S1))

0.4 mass part of ultraviolet absorbers (UV-2) (represented by chemical formula (S2))

0.1 mass part of silica particle dispersion (average particle diameter 16nm, AEROSIL R972, Nippon Aerosil Co., Ltd. product)

A drum 29 having a diameter of 3.5 m was used, and the drum 29 was rotated so that the moving speed of the circumferential surface 29 a was 1.3 m / s. The temperature of the dried gas which flowed out from the nozzle 36b was 40 degreeC. The solvent residual ratio of the casting film 32 which gas starts to supply from the 1st air supply part 35 was 320 mass%.

Experiments 1 to 12 were performed in which the temperature of the peripheral surface 29a of the drum 29, the flow velocity of the gas from the nozzle 36b, and the blowing angle θ1 were different. The temperature of the circumferential surface 29a of the drum 29 is shown in the "Drum circumferential temperature" column of Table 1, the flow velocity of the gas from the nozzle 36b is the "flow rate" column of Table 1, and the blowing angle (theta) 1 is It shows in the "(theta) 1" column of Table 1, respectively. Other conditions are the same as in Example 1. However, the "flow velocity" of each table | surface in the following example and comparative example containing this Example 1 is a relative speed with respect to the moving speed of a casting membrane.

About the film 23 obtained by each experiment, processability and the smoothness of the film surface were evaluated with the following method and reference | standard. About a result, it shows in Table 1.

(A) Evaluation of workability

The obtained film 23 was laminated | stacked and adhere | attached on both surfaces of a polarizing film via an adhesive agent, and the polarizing plate was produced. The polarizing plate was punched out in a rectangle of 10 cm x 10 cm with a knife to obtain a sample for evaluation. From the edge of the evaluation sample, that is, the cut surface, whether or not cracks were generated inside the film 23 and the degree of the identified cracks were evaluated, and this was evaluated as workability. Evaluation was performed based on the following criteria. A crack may be a crack which goes inward from the cut surface of the film 23, and may be peeling between the polarizing film and the film 23. FIG. In the following reference | standards, A-C is a level with which workability is a pass, and D is a level with which workability is a failure.

A: No cracks were found, or although cracks are occurring, the range of cracks generated is less than 25% of the length of one side of the sample.

B: The range in which the crack occurs is in the range of 25% or more and less than 50% of the length of one side of the sample.

C: The range where a crack occurs is in the range of 50% or more and less than 75% of the length of one side of a sample.

D: The range where a crack is generated is 75% or more of the length of one side of a sample.

(B) film smoothness

About the obtained film 23, the smoothness of the film surface was evaluated. The evaluation method is as follows. First, the rectangular sample film whose one side is 6 cm was cut out from the obtained film 23. The refractive index difference of the sample film was measured using the apparatus which converts the refractive index difference of a sample film into thickness difference. The apparatus used is FX-03 FRINGEANALYZER (made by FUJINON Corporation). The refractive index difference was measured over the whole area | region of a sample film, and the average value of the measured value was converted into thickness difference. The thickness difference with respect to the thickness of a film sample was calculated | required, and it was set as evaluation of the smoothness of a film surface. In addition, the thickness of a film sample measures the thickness of six places of a film sample, and is an average value of these measured values. Thickness in six places was measured using the micrometer, respectively. And the smoothness of the film surface was evaluated based on the following criteria. In the following references | standards, A-C is a level with which the smoothness of a film surface is passing, and D is a level with which the smoothness of a film surface is rejected.

A: When thickness difference is less than 1.2% with respect to the thickness TH of a film

B: When the thickness difference is 1.2% or more and less than 1.5% with respect to the thickness TH of the film

C: When the thickness difference is 1.5% or more and less than 1.8% with respect to the thickness TH of the film

D: When the thickness difference is 1.8% or more with respect to the thickness TH of the film

room
city
Yes
·
ratio
School
Yes

pole
Lee
what
of

Bell
Flow
Phil
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two
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rum

second
re
if

On
Degree
(° C)
for
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glass
Flow
rate


(mass%)


U
genus




(m / s)


θ1





(°)
Phil
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castle


end
ball
enemy
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Experiment 1 TAC 40 TG-3 320 30 10 A A Experiment 2 TAC 40 TG-3 320 30 20 A A Experiment 3 TAC 40 TG-3 320 30 30 A A Experiment 4 TAC 40 TG-3 320 30 45 B A Experiment 5 TAC 40 TG-3 320 25 30 A A Experiment 6 TAC 40 TG-3 320 15 30 B A Experiment 7 TAC 40 TG-3 320 15 45 C A Experiment 8 TAC 40 TG-2 320 30 30 A A Experiment 9 TAC 40 TG-1 320 30 30 A A Experiment 10 TAC 40 TG 320 30 30 A A Experiment 11 TAC 40 TG + 1 320 30 30 A A Experiment 12 TAC 40 TG + 2 320 30 30 A A Comparative Example 1



Comparative Experiment 1 TAC 40 TG-3 320 10 30 D A Comparative Experiment 2 TAC 40 TG-3 260 30 30 D A Comparative Experiment 3 TAC 40 TG-3 320 30 50 D A Comparative Experiment 4 TAC 40 TG-4 320 30 30 A D Comparative Experiment 5 TAC 40 TG-5 320 30 30 A D Comparative Experiment 6 TAC 40 TG-6 320 30 30 A D

[Comparative Example 1]

The temperature of the circumferential surface 29a of the drum 29, the solvent residual ratio of the flexible membrane 32 at which gas from the first air supply unit 35 starts to be supplied, the flow rate of the gas from the nozzle 36b, As shown in Table 1, blowing angle (θ1), different comparative experiments 1 to 6 were carried out. Other conditions are the same as in Example 1.

About the film obtained by each comparative experiment, processability and the smoothness of the film surface were respectively evaluated by the same method and reference | standard as Example 1. Table 1 shows the results of processability and smoothness of the film surface.

[Example 2]

The cellulose acylate 11 in the dope 13 of Example 1 was replaced with cellulose diacetate (DAC). The gel point (TG) of the dope 13 was -25 degreeC. From this dope 13, the film 23 whose thickness is 40 micrometers was manufactured. Experiments 1 to 12 were performed in which the temperature of the peripheral surface 29a of the drum 29, the flow velocity of the gas from the nozzle 36b, and the blowing angle θ1 were different. The temperature of the circumferential surface 29a of the drum 29 in each experiment, the flow velocity of the gas from the nozzle 36b, and the blowing angle θ1 are shown in Table 2. Other conditions are the same as in Example 1.

About the film 23 obtained by each experiment, the processability and the smoothness of the film surface were respectively evaluated by the method and reference | standard similar to Example 1. Table 2 shows the results of processability and film smoothness.

room
city
Yes
·
ratio
School
Yes
pole
Lee
what
of

Bell
Flow
Phil
The
of

two
To


(탆) De
rum

second
re
if

On
Degree
(° C)
for
My

glass
Flow
rate


(mass%)


U
genus




(m / s)


θ1





(°)
Phil
The
if
of

Flat
bow
castle


end
ball
enemy
castle Example 2








Experiment 1 DAC 40 TG-3 320 30 10 A A Experiment 2 DAC 40 TG-3 320 30 20 A A Experiment 3 DAC 40 TG-3 320 30 30 A A Experiment 4 DAC 40 TG-3 320 30 45 B A Experiment 5 DAC 40 TG-3 320 25 30 A A Experiment 6 DAC 40 TG-3 320 15 30 B A Experiment 7 DAC 40 TG-3 320 15 45 C A Experiment 8 DAC 40 TG-2 320 30 30 A A Experiment 9 DAC 40 TG-1 320 30 30 A A Experiment 10 DAC 40 TG 320 30 30 A A Experiment 11 DAC 40 TG + 1 320 30 30 A A Experiment 12 DAC 40 TG + 2 320 30 30 A A Comparative Example 2



Comparative Experiment 1 DAC 40 TG-3 320 10 30 D A Comparative Experiment 2 DAC 40 TG-3 260 30 30 D A Comparative Experiment 3 DAC 40 TG-3 320 30 50 D A Comparative Experiment 4 DAC 40 TG-4 320 30 30 A D Comparative Experiment 5 DAC 40 TG-5 320 30 30 A D Comparative Experiment 6 DAC 40 TG-6 320 30 30 A D

[Comparative Example 2]

The temperature of the circumferential surface 29a of the drum 29, the solvent residual ratio of the flexible membrane 32 at which gas from the first air supply unit 35 starts to be supplied, the flow rate of the gas from the nozzle 36b, As shown in Table 2, blowing angle (θ1), different comparative experiments 1 to 6 were carried out. Other conditions are the same as in Example 2.

About the film obtained by each comparative experiment, processability and the smoothness of the film surface were respectively evaluated by the same method and reference | standard as Example 1. Table 2 shows the results of processability and film smoothness.

[Example 3]

The cellulose acylate 11 in the dope 13 of Example 1 was replaced with the cellulose acetate propionate (CAP). Gel point TG of the dope 13 was -10 degreeC. From this dope 13, the film 23 whose thickness is 40 micrometers was manufactured. Experiments 1 to 12 were performed in which the temperature of the peripheral surface 29a of the drum 29, the flow velocity of the gas from the nozzle 36b, and the blowing angle θ1 were different. The temperature of the peripheral surface 29a of the drum 29 in each experiment is shown in Table 3. Other conditions are the same as in Example 1.

About the film 23 obtained by each experiment, the processability and the smoothness of the film surface were respectively evaluated by the method and reference | standard similar to Example 1. Table 3 shows the results of processability and film smoothness.

room
city
Yes
·
ratio
School
Yes
pole
Lee
what
of

Bell
Flow
Phil
The
of

two
To


(탆) De
rum

second
re
if

On
Degree
(° C)
for
My

glass
Flow
rate


(mass%)


U
genus




(m / s)


θ1





(°)
Phil
The
if
of

Flat
bow
castle


end
ball
enemy
castle Example 3








Experiment 1 CAP 40 TG-3 320 30 10 A A Experiment 2 CAP 40 TG-3 320 30 20 A A Experiment 3 CAP 40 TG-3 320 30 30 A A Experiment 4 CAP 40 TG-3 320 30 45 B A Experiment 5 CAP 40 TG-3 320 25 30 A A Experiment 6 CAP 40 TG-3 320 15 30 B A Experiment 7 CAP 40 TG-3 320 15 45 C A Experiment 8 CAP 40 TG-2 320 30 30 A A Experiment 9 CAP 40 TG-1 320 30 30 A A Experiment 10 CAP 40 TG 320 30 30 A A Experiment 11 CAP 40 TG + 1 320 30 30 A A Experiment 12 CAP 40 TG + 2 320 30 30 A A Comparative Example 3



Comparative Experiment 1 CAP 40 TG-3 320 10 30 D A Comparative Experiment 2 CAP 40 TG-3 260 30 30 D A Comparative Experiment 3 CAP 40 TG-3 320 30 50 D A Comparative Experiment 4 CAP 40 TG-4 320 30 30 A D Comparative Experiment 5 CAP 40 TG-5 320 30 30 A D Comparative Experiment 6 CAP 40 TG-6 320 30 30 A D

[Comparative Example 3]

The temperature of the circumferential surface 29a of the drum 29, the solvent residual ratio of the flexible membrane 32 at which gas from the first air supply unit 35 starts to be supplied, the flow rate of the gas from the nozzle 36b, As shown in Table 2, blowing angle (θ1), different comparative experiments 1 to 6 were carried out. The temperature of the peripheral surface 29a of the drum 29 in each comparative experiment is shown in Table 3. Other conditions are the same as in Example 3.

About the film obtained by each comparative experiment, processability and the smoothness of the film surface were respectively evaluated by the same method and reference | standard as Example 1. Table 3 shows the results of processability and film smoothness.

[Example 4]

As the support, a belt 105 shown in FIG. 10 was used instead of the drum 29. The belt 105 is an endless (endless) belt made of stainless steel having a width of 2.1 m and a length of 70 m. The film 23 whose thickness is 40 micrometers from the dope 13 of the following prescriptions by the solution film forming facility (not shown) which connected the flexible chamber 45 shown in FIG. 10 to the 2nd tenter 19 shown in FIG. ) Was prepared. The first tenter 18 was not installed in this solution film forming facility. In addition, in the present Example, the viscosity calculation unit 95 arrange | positioned at the solution film forming facility, the temperature calculation part 101 of the temperature control unit 96, and the 2nd air supply part 135 were not used. In the flexible chamber 45, the duct 40 was provided, and the aspirator 42 was disposed outside the flexible chamber 45. However, the above-mentioned windshield used in place of the suction unit 39 is not provided. 35 degreeC was input into the control part 102 as the dope object temperature, and the temperature of the dope 13 which flows out from the casting die 31 was adjusted so that it might become equal to the dope object temperature. Therefore, the temperature of the flexible dope 13 (dope 13 at the time of flowing out from the flexible die 31) is 35 degreeC. Gel point TG of the dope 13 was 6 degreeC.

<Prescription of dope 13>

Solid ingredients ... Mass ratio in dope 13 is 20 mass%

Solvent… It is a mixture of dichloromethane and alcohol, and the volume ratio is dichloromethane: alcohol = 80: 20

In addition, said solid component is TAC as a polymer 11, a plasticizer, a mat agent, and a UV absorber.

The flexible band 105 was rotated by the driving of the rotary roller 107. The rotating roller 107 was rotated so that the moving speed of the circumferential surface 107a might be 0.7 m / s. The rotary rollers 106 and 107 were supposed to be able to feed the heat transfer medium therein so that the temperature of the flexible band 105 could be adjusted. The heat transfer medium was flowed to the rotating roller 107 facing the casting die 31, and the heat transfer medium was flowed to the other rotating roller 106 for drying the casting film 32. The internal temperature of the flexible chamber 45 was maintained at 40 degreeC using the temperature control installation 110. As shown in FIG. The temperature control device 113 provided on the back surface 105b side of the flexible band 105 is provided with functions of heat generation and cooling. By this function, the temperature of the flexible film 32 until the peeling time on the flexible band 105 was adjusted to become substantially constant, adjusting the temperature control apparatus 113 to predetermined temperature.

The dope 13 was cast on the flexible band 105, and the flexible film 32 was formed. The temperature of the dried gas which flowed out from the nozzle 111b was 40 degreeC. The solvent residual ratio of the flexible membrane 32 which gas starts to supply from the duct 111 was 330 mass%.

The temperature of the circumferential surface 107a of the rotary roller 107, the flow rate of the gas from the nozzle 111b, the direction perpendicular to the membrane surface of the flexible film 32, and the direction of the gas flowing out of the nozzle 111b. Experiment 1-experiment 5 which differed in the angle (blow angle (theta)) which make | form is made. The respective temperatures of the circumferential surface 106a of the rotary roller 106, the circumferential surface 107a of the rotary roller 107, and the surface 105a that is the outer circumferential side of the flexible band 105 are shown in Table 4, "Roller circumferential surface." Flow rate of the gas from the nozzle 111b in the respective fields of “temperature of 106a”, “temperature of rotary roller circumferential surface 107a”, and “temperature of surface 150a of flexible band”. ", And the blowing angle (theta) 1 are shown in the" (theta) 1 "column of Table 4, respectively. Other conditions are the same as in Example 1.

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second
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Experiment 1 TAC 40 TG-3 TG-3 TG-3 330 30 30 A A Experiment 2 TAC 40 TG TG TG 330 30 30 A A Experiment 3 TAC 40 TG + 2 TG + 2 TG + 2 330 30 30 A A Experiment 4 TAC 40 TG-3 TG-3 TG-3 330 30 45 B A Experiment 5 TAC 40 TG-3 TG-3 TG-3 330 15 30 B A

EXAMPLE 5

Instead of the solid component of the dope 13 of Example 1, it was set as the solid component of the following composition. The film 23 was manufactured from the obtained dope 13 by the same method and conditions as the experiment 3 of Example 1. Let this be experiment 1.

100 parts by mass of TAC (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

7.8 parts by mass of triphenyl phosphate

3.9 parts by mass of biphenyl diphenyl phosphate

0.5 mass part of optical performance expression agents (TA-1) (it shows by chemical formula (S3))

0.1 mass part of silica particle dispersion (average particle diameter 16nm, AEROSIL R972, Japan Aerosil Co., Ltd. make)

Instead of the solid component of the dope 13 of Example 1, it was set as the solid component of the following composition. The film 23 was manufactured from the obtained dope 13 by the same method and conditions as the experiment 3 of Example 1. Let this be Experiment 2.

100 parts by mass of TAC (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

6.0 mass parts of sugar ester compound 1 (it shows by chemical formula (S4))

2.0 mass parts of sugar ester compound 2 (it shows with chemical formula (S5))

Ultraviolet absorber (UV-1) 1.0 parts by mass

1.0 part by mass of an ultraviolet absorber (UV-3) (represented by Chemical Formula (S6))

0.1 mass part of silica particle dispersion (average particle diameter 16nm, AEROSIL R972, Japan Aerosil Co., Ltd. make)

Instead of the solid component of the dope 13 of Example 1, it was set as the solid component of the following composition. The film 23 was manufactured from the obtained dope 13 by the same method and conditions as the experiment 3 of Example 1. Let this be Experiment 3.

100 parts by mass of TAC (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

9.0 mass parts of polycondensation ester (shown in Table 5)

1.0 mass part of sugar ester compounds 2

Ultraviolet absorber (UV-1) 1.0 parts by mass

Ultraviolet absorber (UV-3) 1.0 parts by mass

0.1 mass part of silica particle dispersion (average particle diameter 16nm, AEROSIL # R972, Japan Aerosil Co., Ltd. make)

Polycondensation esters Furtherance Dicarboxylic Acid Unit Dior unit Words
only
phrase
article Flat
Germ
minute
character
Amount Terephthalic acid Adipic acid Ethylene glycol Propylene glycol constitutional formula Represented by the chemical formula (S7) Represented by chemical formula (S8) Represented by the formula (S9) Represented by the chemical formula (S10) Molar ratio in the unit One One One One Acetic acid ester 1200

About the film 23 obtained by each experiment, the processability and the smoothness of the film surface were respectively evaluated by the method and reference | standard similar to Example 1. In either experiment, the workability and the smoothness of the film surface were A, which was good as in Experiment 3 of Example 1.

[Example 6]

The film 23 was manufactured by the three-layer covalent lead. The layer which centers the layer of thickness direction between a core layer and a core layer is called surface layer. The dope 13 for core layers is made of dope 13D-1, and the dope 13 for surface layers is made of dope 13D-2, and dope 13D-3. However, these dope 13D-1-13D-3 are put together, and it is set as dope 13D, and the film 23 manufactured by the present Example is made into the film 23D.

<Preparation of TAC Solution (A-1)>

The following composition was put into a mixing tank (not shown), it stirred while heating, each component was melt | dissolved and TAC solution (A-1) was prepared.

The composition of the TAC solution (A-1) is as follows.

100 parts by mass of TAC (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

7.8 parts by mass of triphenyl phosphate

3.9 parts by mass of biphenyl diphenyl phosphate

375 parts by mass of methylene chloride

Methanol 82 parts by mass

5 parts by mass of butanol

<Preparation of Matting Dispersion Liquid (B-1)>

The following composition was put into a disperser (not shown), it stirred, each component was melt | dissolved, and the mat dispersing liquid (B-1) was prepared.

The composition of the matting dispersion (B-1) is as follows.

10.0 parts by mass of silica particle dispersion (average particle diameter 16 nm, AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)

62.5 parts by mass of methylene chloride

Methanol 14.1 parts by mass

Butanol 0.8 parts by mass

10.3 parts by mass of TAC solution (A-1)

<Preparation of ultraviolet absorber solution (C-1)>

The following composition was put into another mixing tank (not shown), it stirred while heating, each component was melt | dissolved and the ultraviolet absorber solution (C-1) was prepared.

The composition of the ultraviolet absorber solution (C-1) is as follows.

10.0 parts by mass of ultraviolet absorber (UV-1)

10.0 parts by mass of ultraviolet absorber (UV-2)

Methylene chloride 54.3 parts by mass

12 parts by mass of methanol

Butanol 0.7 parts by mass

12.9 parts by mass of TAC solution (A-1)

<Preparation of dope 13D-1 for core layer>

To the TAC solution (A-1), an ultraviolet absorber solution (C-1) is added so that 1.6 parts by mass of the ultraviolet absorber (UV-1) and 0.4 parts by mass of the ultraviolet absorber (UV-2) are added per 100 parts by mass of TAC. (13D-1) was prepared.

<Preparation of dope (13D-2) for surface layer>

To the TAC solution (A-1), an ultraviolet absorber solution (C-1) was added to 100 parts by mass of TAC so that 1.6 parts by mass of the ultraviolet absorber (UV-1) and 0.4 parts by mass of the ultraviolet absorber (UV-2) were added. The dope (13D-2) was prepared for matting dispersion (B-1) so that a silica particle might be 0.026 mass part per 100 mass parts of TAC.

<Preparation of dope (13D-3) for surface layer>

To the TAC solution (A-1), an ultraviolet absorber solution (C-1) was added to 100 parts by mass of TAC so that 1.6 parts by mass of the ultraviolet absorber (UV-1) and 0.4 parts by mass of the ultraviolet absorber (UV-2) were added. The dope (13D-3) was prepared for matting dispersion (B-1) so that a silica particle might be 0.078 mass part per 100 mass parts of TAC.

The obtained dope 13D was co-lead in a three-layered constitution by the same method and conditions as in Experiment 3 of Example 1. The first layer in contact with the drum 29 has the surface layer dope 13D-3 having a dry film thickness of 6 μm, and the second layer has a core layer dope 13D-1 having a dry film thickness of 29 μm. The film 23D was produced so that the 3rd layer may be the surface layer which is 5 micrometers in thickness of surface layer dope 13D-2 so that it may become a core layer.

About the obtained film 23D, processability and the smoothness of the film surface were respectively evaluated by the method and the reference | standard similar to Example 1. The processability of the film 23D and the smoothness of the film surface were both A, and were similar to those of the film 23 of Experiment 3 of Example 1.

[Example 7]

The film 23 was manufactured by the three-layer covalent lead. The dope 13 for core layer is made into dope 13E-1, and the dope 13 for surface layer is made into dope 13E-2 and dope 13E-3. However, these dope 13E-1-13E-3 are put together, and it is set as dope 13E, and the film 23 manufactured by the present Example is made into the film 23E. In this example, however, the TAC solution (A-1), matte dispersion (B-1), and ultraviolet absorber solution (C-1) described in Example 6 were used.

<Preparation of dope 13E-1 for core layer>

UV absorber solution (C-1) was added to TAC solution (A-1) so that it may be 1.6 mass parts of ultraviolet absorbers (UV-1) and 0.4 mass parts of ultraviolet absorbers (UV-2) per 100 mass parts of TAC, and dope (13E-1) was prepared.

<Preparation of dope (13E-2) for surface layer>

To the TAC solution (A-1), an ultraviolet absorber solution (C-1) was added to 100 parts by mass of TAC so that 1.6 parts by mass of the ultraviolet absorber (UV-1) and 0.4 parts by mass of the ultraviolet absorber (UV-2) were added. The mat agent dispersion (B-1) was added so that silica particles might be 0.03 mass parts per 100 mass parts of TAC, and methylene chloride became 85 weight% of the dope solvent, and dope (13E-2) was prepared.

<Preparation of dope (13E-3) for surface layer>

To the TAC solution (A-1), an ultraviolet absorber solution (C-1) was added to 100 parts by mass of TAC so that 1.6 parts by mass of the ultraviolet absorber (UV-1) and 0.4 parts by mass of the ultraviolet absorber (UV-2) were added. The mat powder dispersion (B-1) was added so that silica particles might be 0.08 mass part per 100 mass parts of TAC, and methylene chloride became 85 weight% of the dope solvent, and dope was prepared.

The obtained dope 13E was co-lead in a three-layered constitution by the same method and conditions as in Experiment 3 of Example 1. The first layer in contact with the drum 29 has the surface layer dope 13E-3 as a surface layer having a dry film thickness of 6 μm, and the second layer has a core layer application dope 13E-1 as a dry film thickness of 29 μm. The 3rd layer produced the film 23E so that a 3 micrometer-thick-film thickness might become surface layer so that a 3rd layer might become a core layer.

About the obtained film 23E, processability and the smoothness of the film surface were respectively evaluated by the method and the reference | standard similar to Example 1. The processability of the film 23E and the smoothness of the film surface were both A, and were similar to those of the film 23 of Experiment 3 of Example 1.

[Example 8]

The film 23 was manufactured by the three-layer covalent lead. The dope 13 for core layers is set to dope 13F-1, and the dope 13 for surface layers is set to dope 13F-2, and dope 13F-3. The following changes were made from Example 7 to prepare the dope 13F-1 to 3. However, these dope 13F-1-13F-3 are put together, and it is set as dope 13F, and the film 23 manufactured by the present Example is made into the film 23F.

<Preparation of dope 13F-1 for core layer>

Dope (13F-1) was prepared so that 6 mass parts of sugar ester compounds 1, 2 mass parts of sugar ester compounds 2, and 2.4 mass parts of ultraviolet absorbers (UV-1) per 100 mass parts of TAC.

<Preparation of dope (13F-2) for surface layer>

Per 100 mass parts of TAC, 3 mass parts of sugar ester compounds 1, 1 mass part of sugar ester compounds 2, 2.4 mass parts of ultraviolet absorbers (UV-1), and 0.03 mass parts of silica particles were made, and methylene chloride was added to the dope solvent. In addition, it became 85 weight% and dope (13F-2) was prepared.

<Preparation of dope (13F-3) for surface layer>

Per 100 mass parts of TAC, 3 mass parts of sugar ester compounds 1, 2 mass parts of sugar ester compounds 2, 2.4 mass parts of ultraviolet absorbers (UV-1), and 0.08 mass parts of silica particles were made, and methylene chloride was used as a dope solvent. In addition, it became 85 weight% and dope (13F-3) was prepared.

The obtained dope 13F was co-lead in the three-layered constitution by Experiment 3 of Example 1. The first layer in contact with the drum 29 has the surface layer dope 13F-3 as the surface layer having a dry film thickness of 6 μm, and the second layer has the core layer dope 13F-1 as the core having a dry film thickness of 29 μm. The film 23F was produced so that the 3rd layer might be the surface layer of 5 micrometers of film thickness dope 13F-2 so that it might become a layer.

About the obtained film 23F, the processability and the smoothness of the film surface were respectively evaluated by the method and the reference | standard similar to Example 1. The processability of the film 23F and the smoothness of the film surface were all A, and were similar to the film 23 of the experiment 3 of Example 1.

[Example 9]

The film 23 was manufactured by the three-layer covalent lead. The dope 13 for a core layer is made into dope 13G-1, and the dope 13 for surface layers is made into dope 13G-2 and dope 13G-3. The following changes were made from Example 7 to prepare dope 13G-1 to 3. However, these dope 13G-1-13G-3 are made into combined heat dope 13G, and the film 23 manufactured by the present Example is made into the film 23G.

<Preparation of dope (13G-1) for core layer>

The dope (13G-1) was prepared so that 9 mass parts of polycondensation esters and 2.1 mass parts of ultraviolet absorbers (UV-3) per 100 mass parts of TAC.

<Preparation of dope (13G-2) for surface layer>

Per 100 mass parts of TAC, 4 mass parts of polycondensation esters, 2.1 mass parts of ultraviolet absorbers (UV-3), and 0.08 mass part of silica particles were added, and methylene chloride was added so that it might be 85 weight% of a dope solvent, and dope (13G) -2) was prepared.

<Preparation of dope (13G-3) for surface layer>

6 mass parts of sugar ester compound 1, 2.1 mass parts of ultraviolet absorbers (UV-3), and 0.03 mass part of silica particles were added per 100 mass parts of TAC, and methylene chloride was added so that it might become 85 weight% of a dope solvent, and dope ( 13G-3) was prepared.

The obtained dope 13G was co-lead in a three-layered constitution by the same method and conditions as in Experiment 3 of Example 1. The first layer in contact with the drum 29 has the surface layer dope 13G-3 as the surface layer having a dry film thickness of 6 μm, and the second layer has the core layer dope 13G-1 as the core having a dry film thickness of 29 μm. The film 23G was produced so that the 3rd layer may be the surface layer of 5 micrometers of film thickness dope 13G-2 so that it might become a layer.

About the obtained film 23G, processability and the smoothness of the film surface were respectively evaluated by the method and the reference | standard similar to Example 1. The processability of the film 23G and the smoothness of the film surface were both A, which was similar to that of the film 23 of Experiment 3 of Example 1 (both A evaluation).

Claims (9)

As a solution film forming method for producing a film having a thickness in the range of 25 μm or more and 40 μm or less,
Forming a cast film by continuously casting a dope in which cellulose acylate is dissolved in a solvent on a support;
Maintaining the temperature of the flexible film until peeled from the support so as not to be lower than {(gel point TG of the dope) -3} ° C .;
Starting to send gas from the state in which the solvent residual ratio is 300 mass% or more with respect to the said flexible membrane, and advancing drying of the said flexible membrane;
Forming a wet film by peeling the flexible film in the state where the solvent remains from the support; And
Drying the wet film to form the film;
Having;
The gas has a direction of flow within a range of greater than 0 ° and 45 ° or less with a direction perpendicular to the membrane surface of the flexible membrane and has a relative speed with respect to the moving speed of the flexible membrane of 15 m / sec or more and 30 m / sec or less. Sent to the flexible membrane as a pure wind in the range
Solution film formation method. The method according to claim 1,
By controlling the temperature of the support, to adjust the temperature of the flexible film
Solution film formation method. 3. The method according to claim 1 or 2,
The temperature of the said gas sent as said pure wind exists in the range of 20 degreeC or more and 70 degrees C or less.
Solution film formation method. 3. The method according to claim 1 or 2,
The gas is sent in the forward wind until the elastic modulus of the flexible film reaches 50 MPa, and the gas is sent in a counterwind to the flexible film after the elastic modulus is 50 MPa or more.
Solution film formation method. 5. The method of claim 4,
It is arranged downstream from the position where the elastic modulus of the flexible membrane becomes 50 MPa or more, and the opening for sucking the atmosphere around the flexible membrane is sucked by the suction part facing upstream in the moving direction of the flexible membrane to suck the atmosphere around the flexible membrane.
Solution film formation method. 6. The method of claim 5,
Upstream of the suction unit, the membrane surface of the flexible membrane is dried by the pure air to form a coating film.
Solution film formation method. The method of claim 3, wherein
The gas is sent in the forward wind until the elastic modulus of the flexible film reaches 50 MPa, and the gas is sent in a counterwind to the flexible film after the elastic modulus is 50 MPa or more.
Solution film formation method. The method of claim 7, wherein
It is arranged downstream from the position where the elastic modulus of the flexible membrane becomes 50 MPa or more, and the opening for sucking the atmosphere around the flexible membrane is sucked by the suction part facing upstream in the moving direction of the flexible membrane to suck the atmosphere around the flexible membrane.
Solution film formation method. The method of claim 8,
Upstream of the suction unit, the membrane surface of the flexible membrane is dried by the pure air to form a coating film.
Solution film formation method.

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