JP2010158788A - Apparatus for adjusting property and state of polymer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a retardation film which has uniform optical properties and the retardation of which hardly fluctuates before and after a moist-heat endurance test. <P>SOLUTION: A TAC film 3 to be stored in a feed chamber 4 is sent to a tenter part 5. The TAC film 3 is stretched to the Y direction in the tenter part 5. The TAC film 3 sent out of the tenter part 5 is sent to a property/state adjustment unit 6. A steam contact casing 40 is arranged in the property/state adjustment unit 6. A steam feeder 64 feeds steam 400 into the steam contact casing 40. An inlet 41 and an outlet 42 are formed on the steam contact casing 40. A film conveying route is formed from the inlet 41 to the outlet 42. Receiving parts 51, 52 are arranged on the inner wall surface of the steam contact casing 40 in the upper parts of the inlet 41 and the outlet 42, respectively. A water droplet, which is generated by condensation on inner wall surface of the steam contact casing 40 and falls down toward the film conveying route, is received in each of the receiving parts 51, 52. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a property adjusting device for a polymer film.

  Polymer films (hereinafter referred to as “films”) are widely used as optical films because of their features such as excellent light transmission, flexibility, and reduction in weight. Among them, a TAC film formed from cellulose acylate, particularly cellulose triacetate (hereinafter referred to as TAC) having an average degree of acetylation of 57.5% to 62.5% is a photograph because of its toughness and flame retardancy. It is used as a support for a film of photosensitive material. Moreover, since the TAC film is excellent in optical isotropy, it is used for optical films such as a protective film for a polarizing plate, a retardation film, and a viewing angle widening film of a liquid crystal display device whose market is rapidly expanding. .

  As a main method for producing a film, a solution casting method and a melt casting method are known. In the solution casting method, a polymer solution containing a polymer and a solvent (hereinafter referred to as a dope) is cast on a support to form a cast film, and the cast film has self-supporting properties. Thereafter, this is peeled off from the support to form a wet film, and the wet film is dried and wound up as a film. The solution casting method is superior to the melt extrusion method in which a melted polymer is extruded with an extruder to produce a film, and is excellent in optical property isotropy and film thickness uniformity, and obtains a film containing less foreign matter. Therefore, a solution casting method is adopted as a method for producing a film, particularly an optical functional film.

  Further, the solution casting method is roughly classified into a drying method and a cooling gelation method depending on a method for expressing self-supporting property in a cast membrane. In the drying method, the solvent is evaporated from the cast film on the support until the amount of the residual solvent in the cast film falls within a predetermined range. On the other hand, in the cooling gelation method, the casting film on the support is cooled to gel the dope forming the casting film (for example, Patent Document 1).

Furthermore, as a method for adjusting the optical properties of the film, a method of immersing the film in water or exposing the film to water vapor and stretching the film having a moisture content within a predetermined range is known (for example, patents). References 2, 3).
JP 2002-179819 A JP 2003-90915 A JP 2003-62899 A

  By the way, a wet heat durability test is performed on the liquid crystal display device to check whether or not certain characteristics and quality can be ensured under predetermined environmental conditions. Similarly, a wet heat durability test is performed on a film used in a liquid crystal display device or the like. However, it was found that when the wet heat endurance test was performed on this film, the optical characteristics of the film varied. In particular, before and after the wet heat endurance test under high temperature and high humidity conditions (for example, a temperature of 60 ° C. or higher and a humidity of 90% RH), the amount of variation in the thickness direction retardation Rth increases. There were many phenomena that deviated greatly from the range suitable for the device.

  Patent Document 1 discloses a method in which a film obtained by a solution casting method is subjected to a humidification treatment to suppress a dimensional change of the film in a high temperature and high humidity environment. This is to remove the strain in the film by utilizing the phenomenon that the glass transition temperature Tg is lowered due to the increase in the moisture content of the film. By performing such a humidification process, it is considered that the in-plane retardation Re and the thickness direction retardation Rth, which are important optical characteristics in the retardation film, vary, but in Patent Document 1, a letter resulting from the humidification process is used. No mention is made of variations in the foundation Re, Rth. Therefore, the method described in Patent Document 1 does not take into consideration fluctuations in retardation Re and Rth of the retardation film.

  The methods described in Patent Document 2 and Patent Document 3 relate to a method for producing a film that obtains a different Nz factor with a retardation Re in the vicinity of λ / 4, and suppresses fluctuations in optical properties before and after the wet heat durability test. This is not a consideration.

  This invention solves the said subject, and provides the property adjustment apparatus of the polymer film which can manufacture the retardation film with the small variation | change_quantity of the retardation Rth before and behind a wet heat durability test.

  The polymer film property adjusting device of the present invention includes an outer casing, an inner casing disposed in a hollow portion of the outer casing, a water vapor supply unit for supplying water vapor to the hollow portion of the inner casing, and a hollow of the outer casing. The temperature of the first atmosphere is adjusted so that the temperature of the first atmosphere outside the inner casing is higher than the dew point of the second atmosphere in the hollow portion of the inner casing. It is provided with an adjustment part.

  It is preferable to provide a heat insulating material in the inner casing. Moreover, it is preferable to have an inner casing temperature adjustment part which adjusts the temperature of the said inner casing so that the temperature of the said inner casing may be in a state higher than the dew point of the said 1st atmosphere.

  According to the present invention, since the water vapor contact treatment for bringing water vapor into contact with the stretched polymer film is performed, it is possible to produce an optical film having a small variation in retardation Rth before and after the wet heat durability test. Moreover, since the casing in which the water vapor contact treatment is performed has a through hole and a receiving part above the through hole, even if a water droplet generated in the casing due to condensation flows toward the through hole, the receiving part receives the water drop. As a result, the water droplet does not reach the polymer film passing through the through hole. Therefore, according to the present invention, it is difficult for foreign matters to adhere to the surface of the polymer film, so that an optical film having a good surface state can be manufactured.

(Offline stretching equipment)
As shown in FIG. 1, the offline stretching equipment 2 stretches the TAC film 3, and includes a supply chamber 4, a tenter unit 5, a property adjusting device 6, a cooling chamber 7, and a winding chamber 8. Prepare. In the supply chamber 4, a long TAC film 3 manufactured by a film manufacturing facility described later is stored in a state of being wound around a winding core. The supply roller 9 takes out the TAC film 3 from the winding core and supplies it to the tenter unit 5.

(Tenter part)
As shown in FIG. 2, the tenter unit 5 has a film transport path for transporting the TAC film 3 in the X direction, and the TAC film 3 in the film transport path is in a direction orthogonal to the X direction (hereinafter referred to as Y direction). The first rail 11, the second rail 12, and a pair of endless chains (hereinafter referred to as first and second chains) guided by the rails 11 and 12. ) 13 and 14. A plurality of clips 15 are attached to the first and second chains 13 and 14 at regular intervals.

  The rails 11 and 12 are provided along both ends of the film transport path in the Y direction, and are arranged to face each other via the film transport path. A tenter inlet 26 is provided on the upstream side of the rails 11 and 12 in the X direction, and a tenter outlet 27 is provided on the downstream side of the rails 11 and 12 in the X direction. Driving sprockets 21 and 22 are provided on both sides of the tenter outlet 27 in the Y direction of the film conveyance path, and driven sprockets 23 and 24 are provided on both sides of the tenter inlet 26 in the Y direction of the film conveyance path. The first and second chains 13 and 14 are spanned between the driving sprockets 21 and 22 and the driven sprockets 23 and 24, and the first chain 13 is connected by the first rail 11 between these sprockets 21 to 24. The second chain 14 is guided by the second rail 12. When the sprockets 21 to 22 rotate, the first and second chains 13 and 14 move along the rails 11 and 12. As the first and second chains 13 and 14 move, the clip 15 moves along the rails 11 and 12.

  The rails 11 and 12 near the tenter inlet 26 are provided with a grip start position Pa, and the rails 11 and 12 near the tenter outlet 27 are provided with a grip release position Pb. When the clip 15 passes the grip start position Pa, the clip 15 is in a state of gripping the ear portion of the TAC film 3. When the clip 15 passes the grip release position Pb, the clip 15 is in a state of releasing the grip of the ear portion of the TAC film 3. The rails 11 and 12 are arranged such that the Y-direction width Wb of the TAC film 3 at the grip release position Pb is larger than the Y-direction width Wa of the TAC film 3 at the grip start position Pa. From the grip start position Pa to the grip release position Pb, the TAC film 3 is stretched in the Y direction by the clips 15 moving along the rails 11 and 12. A position Pc may be provided between the position Pa and the position Pb in the X direction, and the rails 11 and 12 may be arranged so that the width Wc in the Y direction of the TAC film 3 at the position Pc is larger than the width Wa. . The width Wc may be larger than the width Wb or may be equal to the width Wb.

  An air conditioner (not shown) holds the condition of the atmosphere inside the tenter unit 5 so as to be constant within a predetermined range. Further, if necessary, the tenter unit 5 may divide a plurality of zones in the X direction and change the film heating conditions for each zone. For example, in the X direction, a preheating zone for preheating the TAC film 3, a heating zone for heating the TAC film 3 to a stretchable degree, and a stretching zone for stretching the TAC film 3 may be provided. In addition to these, a heat relaxation zone for stopping the stretching of the TAC film 3 and heating the TAC film 3 so as to relax the strain remaining in the TAC film 3 may be provided on the downstream side in the X direction from the stretching zone. .

  As shown in FIG. 1, an ear clip device 30 is provided between the tenter unit 5 and the property adjusting device 6. The ear clip device 30 cuts off the side edge portion of the TAC film 3 in the Y direction (see FIG. 2) as slit-shaped ear dust. The cut blower 31 connected to the ear clip device 30 cuts the ear dust finely. The air sending device (not shown) sends the ear dust that has passed through the cut blower 31 to the crusher 32, and the crusher 32 cuts the ear dust further finely into chips. Since this chip is reused for dope preparation, this method is effective in terms of cost.

  The TAC film 3 sent to the property adjusting device 6 is subjected to a predetermined process, and the TAC film 3 becomes an optical film 35. Details of the predetermined processing performed in the property adjusting device 6 will be described later. The optical film 35 is sent to the cooling chamber 7, cooled to a predetermined temperature, and then sent to the winding chamber 8.

  In the winding chamber 8, a winding machine 36 having a winding shaft and a press roller 37 are provided. A winding core 36a is attached to the winding shaft. The optical film 35 sent to the winding chamber 8 is wound around the winding core 36 a while being pressed by the press roller 37.

(Property adjuster)
As shown in FIG. 1, the property adjusting device 6 has a property adjusting casing 6a. A water vapor contact casing 40 is provided in the hollow portion of the property adjusting casing 6a.

(Steam contact casing)
The water vapor contact casing 40 is formed of stainless steel (for example, SUS304) or the like, and has a first through hole 41 and a second through hole 42 on a side surface. The ceiling of the water vapor contact casing 40 is formed so as to become lower toward the side surface having the first through hole 41 and the second through hole 42. The plurality of rollers 43 are provided in the hollow portion of the water vapor contact casing 40, and are arranged in a staggered manner from the first through hole 41 toward the second through hole 42. By the plurality of rollers 43, a film transport path is formed in the water vapor contact casing 40 from the first through hole 41 to the second through hole 42. A first receiving portion 51 and a second receiving portion 52 are provided in the steam contact casing 40 above the first through hole 41 and above the second through hole 42, respectively.

  The plurality of rollers (not shown) are provided in the hollow portion of the property adjustment casing 6a, and are directed from the first through hole 41 toward the upstream side in the X direction and from the second through hole 42 toward the downstream side in the X direction. , Each is lined up. A film conveyance path is formed in the property adjustment casing 6a by the plurality of rollers. The film conveyance path of the property adjustment casing 6 a is connected to the film conveyance path of the water vapor contact casing 40 through the first through hole 41 and the second through hole 42.

  As shown in FIGS. 3 and 4, the second receiving portion 52 includes a receiving plate 52 a and first to third side plates 52 b to 52 d. The receiving plate 52 a is provided so as to protrude from the inner wall surface 40 a of the water vapor contact casing 40. The protruding direction of the receiving plate 52a may be a horizontal direction from the inner wall surface 40a, or may be a direction obliquely upward from the inner wall surface 40a with respect to the horizontal direction. Further, the height of the upper surface of the receiving plate 52a may be constant in the Y direction or may be different in the Y direction. The length of the backing plate 52a in the Y direction is preferably longer than the length in the Y direction of the film conveyance path of the water vapor contact casing 40.

  The first to second side plates 52b to 52c are provided substantially vertically and are disposed at both ends of the receiving plate 52a in the Y direction. The third side plate 52d is provided substantially vertically and is disposed on the downstream side in the X direction of the receiving plate 52a. Thus, a second reservoir 57 surrounded by the receiving plate 52a, the first to third side plates 52b to 52d, and the inner wall surface 40a is formed above the second through hole 42. The first to third side plates 52b to 52d may be omitted.

  The inner wall surface 40a above the receiving plate 52a is provided with a ridge 61 that guides water droplets on the inner wall surface 40a to the second reservoir 57. The protrusion 61 is formed in the vertical direction and extends to the second reservoir 57. The ridges 61 may be formed in an oblique direction with respect to the vertical direction.

  A through hole (not shown) is formed in the thickness direction in the receiving plate 52a, and a drain pipe 62 is inserted into the through hole. When the upper surface of the receiving plate 52a intersects the horizontal direction, it is preferable to provide a through hole so as to penetrate the lowest portion of the upper surface of the receiving plate 52a.

  The water collected in the reservoirs 56 and 57 is discharged to the outside through the drain pipe 62. The discharged water may be reused as water vapor after being sent to the water vapor feeder and after a predetermined treatment.

  Similarly, a first reservoir portion 56 (see FIG. 1) similar to the second reservoir portion 57 is formed by the first receiving portion 51 above the first through hole 41. And although illustration is abbreviate | omitted, the protruding item | line similar to the protruding item | line 61 is provided also in the inner wall surface above the 1st through-hole 41. FIG.

(Steam supply machine)
As shown in FIG. 1, the steam supply machine 64 includes a heating unit, a control unit, and a feeding unit. The heating unit heats water to obtain water vapor 400 having a predetermined temperature. The feeding unit supplies water vapor 400 having a predetermined flow rate to the hollow part of the water vapor contact casing 40. The control unit reads the temperature and humidity from a temperature / humidity sensor provided in the hollow portion of the water vapor contact casing 40. And based on the read temperature and humidity, a control part is the heating amount by a heating part, and the flow volume by a sending part so that the temperature T1 and humidity H1 of the atmosphere of the hollow part of the water vapor | steam contact casing 40 may become a desired range. Adjust.

  Next, the effect | action of this invention in the offline extending | stretching equipment 2 is demonstrated. As shown in FIG. 1, the supply roller 9 supplies the TAC film 3 from the supply chamber 4 to the tenter unit 5.

  As shown in FIG. 2, an air conditioner (not shown) adjusts the temperature, humidity, and the like of the atmosphere in the tenter unit 5. Thereby, the temperature of the TAC film 3 which passes the tenter part 5 can be adjusted in a desired range. A drive mechanism (not shown) rotationally drives the sprockets 21 to 24, and the first and second chains 13 and 14 move along the first and second rails 11 and 12. The clip 15 attached to the first and second chains 13 and 14 grips both side edges in the direction Y of the TAC film 3 at the grip start position Pa, and releases the grip of both side edges at the grip release position Pb. . Thus, in the tenter unit 5, the stretching process in the direction Y is performed on the TAC film 3 between the grip start position Pa and the grip release position Pb. The stretching ratio Lx {= (Wb / Wa) × 100} of the TAC film 3 in the tenter portion 5 is preferably 100.5% or more and 300% or less, and more preferably 110% or more and 180% or less.

  As shown in FIG. 1, the side edges of the TAC film 3 sent from the tenter unit 5 are cut by the ear-cutting device 30 and sent to the property adjusting device 6. A predetermined process is performed in the property adjusting device 6. Details of this processing will be described later. The TAC film 3 sent out from the property adjusting device 6 is sent to the cooling chamber 7. The TAC film 3 is cooled to approximately room temperature in the cooling chamber 7. The cooled TAC film 3 becomes an optical film 35, is sent to the winding chamber 8, and is wound around the core 36 a of the winder 36 while being pressed by the press roller 37.

  As shown in FIGS. 1 and 3, the TAC film 3 sent to the property adjusting device 6 is guided to a film transport path provided in the property adjusting casing 6 a and the water vapor contact casing 40. The steam supplier 64 supplies the steam 400 to the steam contact casing 40. In the steam contact casing 40, the wet gas adjusted to a predetermined temperature T1 and humidity H1 comes into contact with the TAC film 3. Thus, the steam contact treatment is performed in the steam contact casing 40.

  By the water vapor contact treatment, the TAC film 3 absorbs water molecules, the glass transition temperature Tg is lowered, and thermal energy of a certain level or more is obtained, so that the diffusion of water molecules in the TAC film 3 is promoted. As a result of promoting the diffusion of water molecules in the TAC film 3, the higher order structure of the polymer molecules is likely to transition to a more stable structure. As a result, the structure of the polymer molecules is stabilized as compared to the process of simply heating the dried TAC film 3. Can be performed in a short time.

  Therefore, according to the present invention, it is possible to produce the TAC film 3 having a small variation in the thickness direction retardation Rth before and after the wet heat durability test.

  In addition, when the temperature of the inner wall surface 40a of the water vapor contact casing 40 is lower than the dew point of the atmosphere in the hollow portion of the water vapor contact casing 40, dew condensation occurs on the inner wall surface 40a. A water droplet generated above the second through hole 42 in the inner wall surface 40 a flows down toward the second through hole 42. If the water droplets reach the TAC film 3 that passes through the second through-hole 42, finally, the foreign matter attached to the water droplets remains on the optical film 35.

  In the present invention, since the second receiving portion 52 is provided on the inner wall surface 40a above the second through-hole 42, the water droplets flowing toward the second through-hole 42 have a receiving plate 52a before reaching the TAC film 3. Received by. In this way, water droplets flowing toward the second through hole 42 can be collected by the second reservoir 57. Similarly, since the first receiving portion 51 is provided on the inner wall surface 40a above the first through hole 41, the water droplets flowing toward the first through hole 41 are first received before reaching the TAC film 3. It is received by the part 51. Therefore, according to the present invention, it is possible to prevent water droplets generated by condensation from reaching the TAC film 3, so that foreign matter remains on the surface of the optical film 35, and finally the surface state is good. An optical film can be manufactured.

  In order to avoid a decrease in the temperature of the inner wall surface 40 a due to a temperature difference from the atmosphere outside the steam contact casing 40, it is preferable to provide a heat insulating material in the steam contact casing 40. In particular, it is preferable to provide a heat insulating material above the first through hole 41 and the second through hole 42 in the water vapor contact casing 40. The heat insulating material may be provided on either the inner wall surface 40a or the outer wall surface of the water vapor contact casing 40, or may be provided inside the water vapor contact casing 40, that is, between the inner wall surface and the outer wall surface. By providing a heat insulating material in the water vapor contact casing 40, it is possible to prevent the heat in the water vapor contact casing 40 and the hollow portion from diffusing to the outside of the water vapor contact casing 40, so that the temperature of the inner wall surface 40a is reduced. As a result, it is possible to suppress the occurrence of condensation on the inner wall surface 40a.

  For example, glass wool or rock wool is preferably used as the material for the heat insulating material.

  Moreover, in order to avoid that the temperature of the inner wall surface 40a falls by the temperature difference with the atmosphere outside the steam contact casing 40, a temperature controller for adjusting the temperature of the steam contact casing 40 may be provided. Any one of these heat insulating materials and temperature controllers may be used, or may be used in combination.

  In the said embodiment, although the 1st through-hole 41 and the 2nd through-hole 42 were formed in the rectangular shape (refer FIG. 4), this invention is not restricted to this, The upper part is horizontal among the inner wall surfaces of each through-hole. You may form in the shape which becomes diagonal with respect to a direction. As a result, the water droplets generated on the upper portion of the inner wall surface of the through hole flow toward the lower portion, that is, the side portion of the inner wall surface of the through hole. As a result, the TAC film 3 passing through the through hole, etc. Can prevent water droplets from flowing down.

  In the said embodiment, although one water vapor | steam contact casing 40 was provided in the hollow part of the property adjustment casing 6a, this invention is not restricted to this, You may provide two or more water vapor contact casings in the hollow part of the property adjustment casing 6a. The direction in which the plurality of water vapor contact casings are arranged is preferably provided on a film conveyance path provided in the property adjustment casing 6a, and may be a horizontal direction or a vertical direction.

  Next, a second embodiment of the present invention will be described. As shown in FIG. 5, a plurality of rollers 43 are arranged in the property adjustment casing 6 a, and a plurality of water vapor contact casings 70 are provided in the film conveyance path between the rollers 43. Each of the plurality of steam contact casings 70 is connected to a steam supply machine 64 (see FIG. 1). The steam supply unit 64 individually supplies the steam contact casing 70 with the steam 400 having a predetermined temperature at a predetermined flow rate so that the temperature and humidity of the atmosphere in each steam contact casing 70 are within a predetermined range. To do. The temperature and flow rate of the water vapor 400 may be adjusted individually for each water vapor contact casing 70 to be supplied.

  The water vapor contact casing 70 includes a top plate 70a, a bottom plate 70b, and a side plate 70c. The top plate 70a is provided with a first through hole 71, and the bottom plate 70b is provided with a second through hole 72. A film conveyance path is formed in the water vapor contact casing 70 from the first through hole 71 to the second through hole 72.

  It is preferable that the upper surface and the lower surface of the top plate 70a are formed so as to become lower from the portion where the first through hole 71 is formed toward the side plate 70c. Similarly, the upper surface and the lower surface of the bottom plate 70b are preferably formed so as to become lower toward the side plate 70c from the portion where the second through hole 72 is formed.

  Further, the discharge hole 73 penetrating the side plate 70 c is formed so as to become lower from the lowest part of the inner wall surface of the steam contact casing 70 toward the outer wall surface of the steam contact casing 70. A container 74 that receives water droplets generated by condensation is provided below the lowest part (hereinafter referred to as the lowest part) of the lower surface of the bottom plate 70b. The water droplets in the container 74 are sent to the outside of the water vapor contact casing 70 by a liquid feeding device (not shown). Instead of the discharge hole 73 that penetrates the side plate 70c, a discharge hole that penetrates the bottom plate 70b may be provided.

  Since the top and bottom surfaces of the top plate 70a and the bottom plate 70b forming the water vapor contact casing 70 are formed so as to be lowered from the portion where the through holes 71 and 72 are formed toward the side plate 70c, the top plate 70a and the bottom plate 70b. Water droplets generated by condensation on the upper and lower surfaces of the liquid flow toward the side plate 70c. On the inner surface and the outer surface of the side plate 70c, water droplets generated by condensation on the side plate 70c flow down along with water droplets from the top plate 70a. Water droplets flowing down the inner surface of the side plate 70 c reach the outer surface of the side plate 70 c through the discharge hole 73. Thus, the water droplets generated in the water vapor contact casing 70 gather at the lowest part of the bottom plate 70b. In the present invention, since the container 74 is provided below the lowest part of the bottom plate 70b, the container 74 can receive water droplets generated by condensation in the water vapor contact casing 70. Therefore, according to the present invention, it is possible to prevent water droplets generated by condensation from reaching the TAC film 3, so that an optical film having a good surface condition can be finally produced.

  Details of each process will be described below.

(Water vapor contact treatment)
The lower limit of the temperature Tf1 of the TAC film 3 in the steam contact treatment is preferably 100 ° C. or higher, more preferably 102 ° C. or higher, and particularly preferably 104 ° C. or higher. The upper limit of the temperature Tf1 is preferably 150 ° C. or less, more preferably 140 ° C. or less, and particularly preferably 130 ° C. or less. If the temperature Tf1 is less than 100 ° C., it is not preferable because the time required for the water vapor contact treatment to reduce the amount of change in the optical properties before and after the wet heat durability test is increased. When the temperature Tf1 exceeds 150 ° C., curling of the TAC film 3 becomes remarkable, which is not preferable. Therefore, the temperature T1 of the atmosphere in the steam contact casing 40 may be adjusted as appropriate so that the temperature Tf1 falls within the above range.

The relative humidity H1 of the atmosphere in the water vapor contact casing 40 is preferably 20% RH or more and 100% RH or less, more preferably 40% RH or more and 100% RH or less, and 70% RH or more and 100% RH or less. It is particularly preferred that When the relative humidity H1 is less than 20% RH, the effect of suppressing ΔRth _WET is small, which is not preferable.

  Moreover, the range of the treatment time P1 of the water vapor contact treatment is not particularly limited, but is preferably as short as possible from the viewpoint of production efficiency as long as the effect of the present invention is exhibited. For example, the upper limit of the processing time P1 is preferably 60 minutes or less, and more preferably 10 minutes or less. On the other hand, the lower limit of the processing time P1 is, for example, preferably 5 seconds or more, more preferably 10 seconds or more, and particularly preferably 30 seconds or more.

(Condensation prevention treatment)
In the hollow portion of the property adjusting casing 6a, a dew condensation prevention zone for performing a dew condensation prevention process may be provided upstream of the water vapor contact casing 40. Further, a partition plate that partitions the hollow portion of the property adjusting casing 6a into a plurality of zones in the X direction may be provided, and a dew condensation prevention zone and a water vapor contact zone may be provided in order from the upstream side in the X direction. When the dew point of the atmosphere in the dew condensation prevention zone is higher than the temperature of the water vapor contact casing 40, dew condensation occurs on the outer wall surface of the water vapor contact casing 40. In such a case, a receiving portion having the same structure as that of the first receiving portion 51 may be provided in a portion of the outer wall surface of the water vapor contact casing 40 above the first through hole 41.

  In order to suppress dew condensation on the TAC film 3 during the water vapor contact treatment, the high temperature gas is applied to the TAC film 3 before the water vapor contact treatment is performed, so that the temperature of the TAC film 3 of the above embodiment falls within a predetermined range. It is preferable to perform a prevention process. It is preferable to sequentially perform the dew condensation prevention treatment and the water vapor contact treatment sequentially.

  The range of the temperature Tf0 of the TAC film 3 at the completion of the dew condensation prevention treatment is preferably set to a temperature higher by ΔT0 than the dew point of the atmosphere in the water vapor contact casing 40. ΔT0 is preferably 5 ° C. or higher and 150 ° C. or lower, and more preferably 10 ° C. or higher and 150 ° C. or lower. When ΔT0 is less than 5 ° C., the effect of preventing condensation is reduced, which is not preferable. If ΔT0 exceeds 150 ° C., the film tends to soften, which is not preferable. More specifically, Tf0 is preferably 80 ° C. or higher and 160 ° C. or lower, and more preferably 100 ° C. or higher and 140 ° C. or lower.

(Heat treatment)
Similarly, a heat treatment zone for performing heat treatment may be provided downstream of the water vapor contact casing 40 in the hollow portion of the property adjusting casing 6a. Moreover, a partition plate that partitions the hollow portion of the property adjusting casing 6a into a plurality of zones in the X direction may be provided, and a water vapor contact zone and a heat treatment zone may be provided in order from the upstream side in the X direction. A receiving portion having the same structure as that of the receiving portion 51 may be provided on the outer wall surface of the water vapor contact casing 40 above the second through hole 42.

  It is preferable to apply a dry gas to the TAC film 3 that has been subjected to the water vapor contact treatment, and perform a heat treatment to bring the temperature of the TAC film 3 within a predetermined range. It is preferable to sequentially perform the steam contact treatment and the heat treatment sequentially. By this heat treatment, it is possible to produce a TAC film 3 having a small amount of variation in each retardation, dimensional change in the X direction, or Y direction not only before and after the wet heat durability test but also before and after the dry heat durability test. Here, the dry heat durability test refers to a durability test performed under conditions of high temperature and low humidity (for example, a temperature of 80 ° C. or higher and a humidity of 5% RH or lower).

  The lower limit of the temperature Tf2 of the TAC film 3 in the heat treatment is preferably 110 ° C. or higher, and more preferably 120 ° C. or higher. Moreover, it is preferable that the upper limit of temperature Tf2 is 160 degrees C or less, and it is more preferable that it is 150 degrees C or less. Therefore, it is preferable that the temperature of the dry gas is within a range equivalent to the temperature Tf2. When the temperature Tf2 is less than 110 ° C. or the temperature Tf2 exceeds 160 ° C., the amount of variation in retardation before and after the wet heat durability test and the dry heat durability test, the dimensional change in the X direction, and the dimension in the Y direction This is not preferable because the amount of change cannot be suppressed. Further, the temperature Tf2 is preferably higher than the temperature Tf1.

  The relative humidity H2 of the dry gas in the heat treatment is preferably 20% RH or less, and more preferably 10% RH or less. When the relative humidity H2 of the dry gas exceeds 20% RH, the moisture content of the film is increased, and the roll shape of the roll is deformed with time.

  The upper limit of the heat treatment time P2 is preferably 5 minutes or less, and more preferably 4 minutes or less. On the other hand, the lower limit of the processing time P2 is preferably 1 minute or longer. When the treatment time P2 exceeds 5 minutes or less than 1 minute, the amount of variation in each retardation before and after the wet heat endurance test and the dry heat endurance test, and the dimensional change amount in the X or Y direction can be suppressed. It is not preferable because it cannot be done.

  In the said embodiment, although the property adjustment apparatus 6 comprised from the property adjustment casing 6a and the water vapor | steam contact casing 40 distribute | arranged to the hollow part of the property adjustment casing 6a was used, this invention is not limited to this, Property adjustment casing 6a may be omitted and the water vapor contact casing 40 may be used as a property adjusting device.

  In the stretching process of the above embodiment, the TAC film 3 is stretched in the Y direction. However, the present invention is not limited to this, and the TAC film 3 may be stretched in the X direction, and the TAC film 3 may be stretched in the X direction and the Y direction. It may be stretched. The stretching means may be any means that can apply a predetermined tension to the TAC film 3 like the tenter unit 5.

  As the TAC film 3 to be subjected to the steam contact treatment, it is preferable to use a TAC film that has been sufficiently dried, that is, a solvent in which almost no solvent remains and the fluidity of polymer molecules has almost disappeared. The amount is preferably 5% by weight or less, more preferably 2% by weight or less, and particularly preferably 0.3% by weight or less. Here, the dry solvent-based residual solvent amount indicates the amount of solvent remaining in the wet film or the TAC film 3. The amount of residual solvent is {(xy) / y} × where x is the weight of the sample film at the time of collection, and y is the weight after drying the sample film. 100.

  The width of the TAC film 3 is preferably 600 mm or more, more preferably 1400 mm or more and 2500 mm or less, and the effect of the present invention is exhibited even when the width is larger than 2500 mm. Further, the thickness of the TAC film 3 is preferably 20 μm or more and 200 μm or less, and more preferably 40 μm or more and 100 μm or less.

  As the TAC film 3, it is preferable to use a film manufactured by a solution casting method, and it is particularly preferable to use a film manufactured by a cooling gelation method. Hereinafter, an outline of the cooling gelation method will be described. In addition, the same code | symbol is attached | subjected to the same member as the said embodiment, and the detailed description is abbreviate | omitted.

  As shown in FIG. 6, the film manufacturing facility 80 performs a cooling gelation type solution film forming method. The temperature of the casting dope 81 containing the polymer and the solvent is maintained to be substantially constant within a range of 30 ° C. or more and 40 ° C. or less. Under the control of a control unit (not shown), the casting drum 82 rotates around the shaft 82a. By this rotation, the peripheral surface 82b travels in the direction Z1 at a predetermined speed (from 50 m / min to 200 m / min). Moreover, the temperature of the peripheral surface 82b is kept substantially constant within a range of −10 ° C. or more and 10 ° C. or less by the heat transfer medium circulation device 83.

  The casting die 84 discharges the casting dope 81 to the peripheral surface 82b. The decompression chamber 85 decompresses the downstream side in the direction Z1 of the bead formed by the discharged casting dope 81 to stabilize the bead. A cast film 86 is formed on the peripheral surface 82b by the cast dope 81 thus discharged. The casting dope 81 forming the casting film 86 is gelled by cooling on the peripheral surface 82b. As a result of the gelation of the casting dope 81, the casting film 86 exhibits self-supporting properties. In the present specification, gelation means that the fluidity of the casting dope 81 is lost while the solvent contained in the casting dope 81 is retained in the molecular chain of the polymer. As a result, the fluidity of the casting dope 81 is lost. It means being in a state. After the casting film 86 has a self-supporting property, it is peeled off from the peripheral surface 82 b while being supported by the peeling roller 89 as a wet film 88. The residual solvent amount of the cast film 86 at the time of peeling is preferably 250% by weight or more and 280% by weight or less.

  The wet film 88 in which the gelled state is maintained is sequentially sent to the crossover unit 90, the pin tenter 91, and the tenter unit 5. The tenter unit 5 may be omitted. In the transfer part 90, the pin tenter 91, and the tenter part 5, predetermined dry air is applied to the wet film 88 to evaporate the solvent contained in the wet film 88. The draw tension (= V2 / V1) in the transition part 90 is preferably set to 1.00 or more and 1.05 or less. Here, V1 is the peripheral speed of the first transport roller, and V2 is the peripheral speed of the second transport roller provided on the downstream side of the first transport roller.

  The pin tenter 91 and the tenter unit 5 perform a stretching process for stretching the wet film 88 in a predetermined direction while evaporating the solvent. The residual solvent amount of the wet film 88 introduced into the pin tenter 91 is preferably 200% by weight or more and 250% by weight or less. The residual solvent amount of the wet film 88 introduced into the tenter unit 5 is preferably 30% by weight or more and 200% by weight or less.

  In the drying chamber 97, predetermined dry air is applied to the wet film 88 to evaporate the solvent contained in the wet film 88. The temperature of the wet film 88 in the drying chamber 97 is preferably 140 ° C. or higher and 180 ° C. or lower.

  The wet film 88 sufficiently dried in the drying chamber 97 becomes the TAC film 3 and is cooled in the cooling chamber 7 until a predetermined temperature is reached. In addition, the forced neutralization device 98 neutralizes the voltage so that the charged voltage of the TAC film 3 falls within a predetermined range (for example, −3 kV to +3 kV). The knurling roller 99 imparts knurling to both edges of the TAC film 3 by embossing. Thereafter, the TAC film 3 is sent to the winding chamber 8 and is wound around the winding core 36 a of the winding machine 36 while being pressed by the press roller 37.

  In the film manufacturing facility 80, the tenter unit 5 is provided between the pin tenter 91 and the drying chamber 97, but the present invention is not limited to this, and may be provided between the drying chamber 97 and the cooling chamber 7.

  In the above embodiment, in the off-line stretching facility 2 (see FIG. 1), the TAC film 3 produced by the solution casting method is subjected to stretching treatment and then subjected to water vapor contact treatment, but the present invention is limited to this. Absent. When the TAC film 3 accommodated in the supply chamber 4 (see FIG. 1) has undergone the stretching process in the offline stretching facility 2, the tenter unit 5 is omitted, and the TAC film 3 taken out from the winding core is left as it is. Steam contact treatment may be performed.

  In the said embodiment, although the casting drum 82 was used as a support body in the film manufacturing equipment 80, this invention is not limited to this, You may use the endless band which drive | works. Alternatively, the casting film 86 may be allowed to exhibit self-supporting properties by bringing dry air into contact with the casting film 86 and evaporating the solvent from the casting film 86.

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

  In the above embodiment, the TAC film is used. However, the present invention is not limited to the TAC film, and is composed of other polymers such as cellulose acylate and cyclic olefin, and can be obtained by a solution casting method or a melt casting method. It can also be used for polymer films produced by

  The polymer that can be used in the melt film-forming method is not particularly limited as long as it is a thermoplastic resin, and examples thereof include cellulose acylate, lactone ring-containing polymer, cyclic olefin, and polycarbonate. Of these, cellulose acylate and cyclic olefin are preferred, cellulose acylate containing an acetate group and propionate group, and cyclic olefin obtained by addition polymerization, more preferably cyclic olefin obtained by addition polymerization. It is.

(Cellulose acylate)
As the cellulose acylate, triacetyl cellulose (TAC) is particularly preferable. Of the cellulose acylates, those in which the hydroxyl group of cellulose is esterified with a carboxylic acid, that is, the substitution degree of the acyl group satisfies all of the following formulas (I) to (III) are more preferable. In the following formulas (I) to (III), A and B represent the substitution degree of the acyl group, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 to 22 carbon atoms. It is. In addition, it is preferable that 90 weight% or more of TAC is a particle | grain of 0.1 mm-4 mm.
(I) 2.5 ≦ A + B ≦ 3.0
(II) 0 ≦ A ≦ 3.0
(III) 0 ≦ B ≦ 2.9

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

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

  Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more kinds of acyl groups are used, it is preferable that one of them is an acetyl group. When the sum of the substitution degrees by the hydroxyl groups at the 2nd, 3rd and 6th positions is DSA, and the sum of the substitution degree by an acyl group other than the acetyl group at the 2nd, 3rd and 6th hydroxyl groups is DSB, the value of DSA + DSB is More preferably, it is 2.22 to 2.90, and particularly preferably 2.40 to 2.88. The DSB is 0.30 or more, particularly preferably 0.7 or more. Further, 20% or more of DSB is a substituent at the 6-position hydroxyl group, more preferably 25% or more is a substituent at the 6-position hydroxyl group, more preferably 30% or more, and particularly 33% or more is a 6-position hydroxyl group. It is preferable that it is a substituent. Furthermore, the cellulose acylate having a substitution degree of 6-position of cellulose acylate of 0.75 or more, further 0.80 or more, and particularly 0.85 or more can be mentioned. With these cellulose acylates, a solution having a preferable solubility (dope) can be produced. In particular, a good solution can be prepared in a non-chlorine organic solvent. Furthermore, it is possible to produce a solution having a low viscosity and good filterability.

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

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

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

  Among these, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. One kind of alcohol having 1 to 5 carbon atoms in addition to dichloromethane from the viewpoint of physical properties such as solubility of TAC, peelability of cast film from the support, mechanical strength of the film, and optical properties of the film It is preferable to mix several kinds. The content of the alcohol is preferably 2% by weight to 25% by weight and more preferably 5% by weight to 20% by weight with respect to the whole solvent. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, but methanol, ethanol, n-butanol or a mixture thereof is preferably used.

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

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

(Cyclic olefin)
The cyclic olefin is preferably polymerized from a norbornene compound. This polymerization can be carried out by either ring-opening polymerization or addition polymerization. Examples of the addition polymerization include those described in Japanese Patent No. 3517471, Japanese Patent No. 3559360, Japanese Patent No. 3867178, Japanese Patent No. 3817721, Japanese Patent No. 3907908, Japanese Patent No. 3945598, Japanese Patent Publication No. 2005-527696, Japanese Patent Laid-Open No. 2006-2006. No. 28993 and International Publication No. 2006/004376 pamphlet. Particularly preferred is the one described in Japanese Patent No. 3517471.

  As the ring-opening polymerization, WO 98/14499 pamphlet, Japanese Patent No. 30605532, Japanese Patent No. 3320478, Japanese Patent No. 3273046, Japanese Patent No. 3404027, Japanese Patent No. 3428176, Japanese Patent No. 3687231, Japanese Patent No. 3873934, Patent No. 3912159 is mentioned. Among them, those described in WO98 / 14499 pamphlet and Japanese Patent No. 30605532 are preferable.

  Of these cyclic olefins, those of addition polymerization are more preferred.

(Lactone ring-containing polymer)
This refers to those having a lactone ring structure represented by the following (General Formula 1).

In (General Formula 1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.

  The content ratio of the lactone ring structure of (General Formula 1) is preferably 5 to 90% by weight, more preferably 10 to 70% by weight, and still more preferably 10 to 50% by weight.

  In addition to the lactone ring structure represented by (General Formula 1), at least selected from (meth) acrylic acid esters, hydroxyl group-containing monomers, unsaturated carboxylic acids, and monomers represented by the following (General Formula 2). A polymer structural unit (repeating structural unit) constructed by polymerizing one kind is preferred.

In General Formula 2, R ⁴ represents a hydrogen atom or a methyl group, X is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ⁵ group, or an -C-O-R ⁶ group, Ac group represents an acetyl group, R ⁵ and R ⁶ represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms.

  For example, those described in International Publication No. 2006/025445, JP 2007-70607 A, JP 2007-63541 A, JP 2006-171464 A, and JP 2005-162835 A can be used. .

(Use)
The optical film of the present invention is useful as a polarizing plate protective film or a retardation film. An optically anisotropic layer, an antireflection layer, an antiglare function layer, and the like may be added to the optical film to form a high function film such as a viewing angle widening film and an antiglare film.

  When used as a retardation film, the in-plane retardation Re is preferably 30 nm to 100 nm, and the thickness direction retardation Rth is preferably 70 nm to 300 nm.

It is explanatory drawing which shows the outline | summary of an offline extending | stretching installation. It is a top view which shows the outline | summary of a tenter part. It is a perspective view which shows the outline | summary of the inside of a 1st water vapor | steam contact casing. It is a disassembled perspective view of the receiving part provided in the inside of the 1st water vapor contact casing. It is a fragmentary sectional view showing the outline of the 2nd steam contact casing. It is explanatory drawing which shows the outline | summary of a film manufacturing equipment.

2 offline stretching equipment 3 TAC film 5 tenter part 6 property adjusting device 35 optical film 40 water vapor contact casing 41, 42 through hole 51, 52 receiving part 56, 57 reservoir 64 water vapor feeder 80 film production equipment 400 water vapor

Claims (3)

An outer casing,
An inner casing disposed in the hollow portion of the outer casing;
A steam supply section for supplying steam to the hollow portion of the inner casing;
Of the hollow part of the outer casing, the temperature of the first atmosphere so that the temperature of the first atmosphere outside the inner casing is higher than the dew point of the second atmosphere in the hollow part of the inner casing. An apparatus for adjusting the property of a polymer film, comprising: an atmospheric temperature adjusting unit for adjusting the temperature.   The property adjusting device for a polymer film according to claim 1, wherein a heat insulating material is provided in the inner casing.   3. The polymer film according to claim 1, further comprising an inner casing temperature adjusting unit that adjusts the temperature of the inner casing so that the temperature of the inner casing is higher than a dew point of the first atmosphere. Property adjusting device.

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