JP5402958B2 - Method for producing cellulose acylate film - Google Patents

Description

  The present invention relates to a method for producing a cellulose acylate film (hereinafter sometimes simply referred to as a film) used as a base for silver halide photographic light-sensitive materials and liquid crystals.

  Solution casting film forming methods for producing films include, for example, JP-A-62-46625, JP-A-46646, JP-A-4-52125, JP-A-11-90944, JP-A-11-235728, and JP-A-11. No.-323017 and the like.

  The production of the film by the solution casting film forming method will be described with reference to FIG. In addition, the adjustment process of the cellulose acylate solution (hereinafter also abbreviated as “dope”) such as mixing and stirring is omitted.

  In FIG. 10, reference numeral 10 denotes a storage pot, in which dope is introduced from the introduction port 11, additive is introduced from the introduction port 12, a predetermined temperature is maintained by the heat insulation jacket 13, and the gear pump 15 is opened by opening the discharge port 14. Then, the liquid is fed through the casting die 16 and discharged onto the endless support 17 to form a coating film. The coating is cooled as the support 17 travels, and is peeled off from the support 17 at the peeling point 18 and drawn out as a web 19. The drawn-out web 19 is sent to a drying device 21 through a tenter (width regulating device) 20 and dried, and becomes a roll-shaped original winding product by a winding device 22.

  The above manufacturing method is an example, and there is also a manufacturing method in which the adjusted additive line is mixed with the dope liquid feeding line and sent to the casting die.

  In the method for producing a film by the above-described solution casting film forming method, a method or an apparatus for controlling winding is known. For example, JP-A-63-74850 discloses embossing, JP-A-4-85249. Publications and the like disclose that emboss touch winding is performed.

Regarding the roll-shaped winding of the product, there is no known prior art document that refers to the winding diameter itself from the form of the product. There are known techniques for measuring the winding hardness itself in winding.
It is also known about the charging potential that the roll-shaped product is charged with winding.

Regarding the tape transfer of the core part, there is no description about the relationship between the film thickness and the tape thickness and the position where the tape is applied.
It is known about the cleanliness of the winding part when winding the product.

  Although the evaporation / condensation of the plasticizer in the drying or thermal straightening process and the contamination caused thereby are known, there is no known document that mentions the method for suppressing the contamination of the equipment.

JP 62-46625 A JP-A 62-46646 JP-A-4-52125 JP-A-11-90944 JP-A-11-235728 JP 11-323017 A JP-A-63-74850 Japanese Patent Laid-Open No. 4-85249

  In recent years, the cellulose ester film is moving in the direction of thinning, but on the basis of the winding tension of a conventional 120 μm thick film, for example, when trying to wind a 40 μm thick film on the extension of the film cross section and tension stress. The tension is too weak, the roll-shaped product form becomes a horse's spine in a loosely wound state, and the film is deformed into a polygonal shape, and in such a state, the film of the deformed part is fixed as time passes. The deformed portion remained, causing a problem in flatness quality. As a solution to solve this problem, when winding is performed with a tension higher than the conventional tension stress, the band shape is caused by tape transfer based on the tape thickness or slight film thickness unevenness due to radial stress. The production loss is increased due to the deformation of the adhesive film and the partial blocking that causes the pyramidal base deformation based on the partial adhesion improvement.

  The winding tension condition that solves the above problem is a pinpoint condition when the film thickness is in the direction of thinning to 85 to 20 μm, and the number of products increases more and more. It is in a difficult state.

  That is, the problems associated with the winding of the thin film film are accompanied by great difficulty whether the winding tension is lowered or increased. The embossing touch winding method taught in the above-mentioned Japanese Patent Laid-Open No. 4-85249 can set the initial winding tension to be low and is suitable for winding a thin film. However, in order to perform this method, it is necessary to prepare and replace several types of touch rolls corresponding to films of various width sizes, and time loss associated with replacement work, and several types of touch rolls are prepared. Therefore, there is a problem that the production cost increases.

  In addition, if the product (original winding) wound up in a roll shape is not sufficiently neutralized, when the film is taken out from the original winding and secondary processing is performed, for example, a coating for forming a functional film is applied. If it is carried out, there is a case where a group is formed on the coated surface due to uneven charge amount, resulting in an increase in manufacturing loss. In recent years, in particular, the direction of high-speed coating is aimed at improving productivity, and the charging potential when the film is unwound from the original winding becomes higher and charging unevenness is more likely to occur. It is connected to the outbreak.

  Although a small amount of foreign matter is adhering to the roll-shaped original film itself, it is not preferable for secondary processing. In particular, in the process of drying and heat correction (including cooling), a small amount of foreign matter is transported. If the film is attached to a roll or film, the film surface temperature at the process entrance is 100 to 160 ° C. and the film is in a softened state. Since it becomes a blister and it becomes a manufacturing loss, it is very unpreferable.

In the process of drying and thermal straightening (including cooling), the film plasticizer evaporates because it is performed at a high temperature, but when it comes into contact with a low temperature part such as a wall or equipment, it condenses depending on the type of plasticizer and is in a liquid state. Or it becomes a powder state and it becomes a wall surface and equipment contamination. When a plasticizer in a liquid state or a powder state drops from such a contaminated portion and adheres to the film surface, it causes a quality problem, resulting in a production loss. For this reason, it is necessary to stop the operation of the process to clean the contamination of the wall surface and equipment, which not only increases the maintenance load but also reduces the manufacturing efficiency. Further, for example, when circulating air is used in the drying process, the concentration of the plasticizer in the gaseous state becomes high, and the problem of contamination of the equipment is more prominent.

  When winding a film formed, a tape having a thickness of 100 to 150 μm is conventionally used as a tape for bonding the film tip to a core (core) in consideration of workability. In the case of a film having a thickness of 120-100 μm to 20-85 μm, the problem of transfer to the film surface due to the thickness of the tape becomes significant, and a solution is required.

  As the winding is completed, the winding speed of the finished product (original winding) is reduced and eventually becomes zero. With this change in the conveying speed, the film conveying position is changed to the edge position control (E.P.C. Even if the control of) works, it changes slightly. Even after changing to a new core, the film transport position changes slightly with rapid acceleration. For this reason, a phenomenon that wrinkles are generated on the film due to abrupt change of the conveyance position particularly at the start of winding has occurred. This causes a situation in which wrinkles are generated on the film because rapid control works to correct the change in the winding position at the time of the increased deceleration. Since the occurrence of such a situation also leads to a manufacturing loss, a solution is demanded.

  As is apparent from the above, the present invention is a film that winds the film without loosening, prevents deformation such as horseback spine and pyramid blocking failure, removes static electricity from the wound film, reduces charge amount, and prevents foreign matter from entering. The objective is to clarify the manufacturing method of film such as thin TAC film that can clean the surface and prevent the contamination of the equipment by the evaporated plasticizer, especially the prevention of equipment contamination by the evaporated plasticizer. It is an object to clarify a method for producing a film such as a thin TAC film that has been made possible.

The above object of the present invention can be achieved by the following constitution.
1. In a method for producing a cellulose acylate film by a solution casting film forming method, a drying and / or heat straightening step is performed when a web peeled from a casting support is dried and heat-corrected as necessary and wound on a core. web by arranging the means for removing the plasticizer evaporates during winding gastric row, means for removing the plasticizer, of the total feed air flow in the drying and / or heat straightening process 5% to 50% of A method for producing a cellulose acylate film, which is a means for adding fresh air .

2 . 2. The method for producing a cellulose acylate film as described in 1 above, wherein the thickness of the cellulose acylate film is from 20 to 85 μm.

The following configurations are listed as reference inventions of the present invention.
(A) The method for producing a cellulose acylate film as described in 1 above, wherein the means for removing the plasticizer is a means for lowering the vapor pressure of the plasticizer during the drying and / or thermal straightening process.
(B) The method for producing a cellulose acylate film as described in 1 above, wherein the means for removing the plasticizer is a heating means for the metal surface to which the plasticizer comes into contact during the drying and / or thermal straightening step.
(C) The means for removing the plasticizer is means for circulating the air supplied during the drying and / or heat straightening process and removing the plasticizer evaporated in the circulation process. A method for producing the cellulose acylate film described in 1.
Furthermore, the following is mentioned as reference invention of this invention.
(1) In a method for producing a cellulose acylate film by a solution casting film forming method, when the web peeled from the casting support is dried and heat-corrected as necessary, it is embossed on the web. In addition, at the start of the initial winding, the winding is performed so that 280 N / m width> pressing force (N / m width) + winding initial tension (N / m width)> 60 N / m width by touch roll winding A method for producing a cellulose acylate film, comprising:

(2) The method for producing a cellulose acylate film as described in (1) above, wherein a flat roll that is substantially in contact with only the emboss formed on the web is used as the touch roll.

(3) The embossing formed on the web is characterized in that the height is set to 0.05 to 0.3 of the web film thickness, and the width is set to 0.005 to 0.02 of the film width. A method for producing a cellulose acylate film described in 1) or (2).

(4) The cellulose acylate as described in (1), (2) or (3) above, wherein the pressing force of the touch roll against the embossing formed at both ends of the web can be adjusted independently at both ends. A method for producing a film.

(5) In a method for producing a cellulose acylate film by a solution casting film forming method, when the web peeled from the casting support is dried and heat-corrected as necessary, it is wound on a winding core. A method for producing a cellulose acylate film, wherein the product is wound so that the diameter of the original roll is different at both ends.

(6) The method for producing a cellulose acylate film as described in (5) above, wherein a difference in radius between both ends of the product original winding is within 5 mm.

(7) In the method for producing a cellulose acylate film by a solution casting film forming method, when the web peeled from the casting support is dried and heat-corrected as necessary, it is wound on a winding core. A method for producing a cellulose acylate film, wherein the winding hardness of the original roll of the product is wound so that the hardness of the embossed portion is equal to (the embossed portion hardness-the hardness of the midpoint between the film end portion and the central portion) <170.

(8) In a method for producing a cellulose acylate film by a solution casting film forming method, when the web peeled from the casting support is dried and heat-corrected as necessary, the web is wound on the winding core. The thickness of the tape to be bonded to the tape is 50 μm or less, and the tape is bonded over the entire width of the core width, or the adhesive tape is attached only on one side of the emboss applied to both ends of the web, and the web is wound. A method for producing a cellulose acylate film.

(9) In a method for producing a cellulose acylate film by a solution casting film forming method, when a web peeled from a casting support is dried and heat-corrected as necessary, a neutralizing device or forced A method for producing a cellulose acylate film, comprising: arranging a charging device; and winding a web so that a charging potential of the film is within ± 2 kV when the film is re-drawn from the original winding.

(10) In the method for producing a cellulose acylate film by a solution casting film-forming method, when the web peeled from the casting support is dried and, if necessary, heat-corrected, it is wound on a core, a drying device, or A method for producing a cellulose acylate film, characterized by disposing a film cleaning device before introduction into a heat straightening device and / or after carrying it out to remove dust adhering to a web.

(11) The method for producing a cellulose acylate film as described in any one of (1) to (10) above, wherein the cellulose acylate film has a thickness of 20 to 85 μm.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of films, such as a thin film TAC film which enabled the contamination prevention of the apparatus by the evaporated plasticizer, etc. was provided. Similar effects can be obtained by the reference inventions (A), (B), and (C) of the present invention. And in the winding of the film by the method of the reference invention of the present invention, the double-sided adhesive tape of the core is on the embossed part, the touch roll is touched to the embossed part, the center part is not touched, and the film in the original roll Since the close contact is governed by the winding tension, the occurrence of tape transfer can be reduced. In addition, the original roll product with no difference in the upper and lower radius ratio can be supplied even with low tension winding, and production loss due to a band-like failure or a tape transfer failure is reduced, resulting in an improvement in production yield. Further, the winding diameter of the original winding is uniform left and right and is not in a loose winding state, so that a horse back failure does not occur.

  It is possible to suppress the charge potential of the film when the original winding is re-drawn by neutralizing and adding the matting agent, thereby suppressing the occurrence of uneven coating due to the charging of the film, and it is possible to reduce loss and improve yield.

  Thermal straightening and film cleanup prevent the occurrence of film blistering due to foreign matter, and the installation of a foreign matter removal device in the final process can most effectively prevent foreign matter from being caught. Further, it is possible to prevent the occurrence of a coating failure at the time of new coating of the functional layer film due to re-feeding.

  In particular, according to the present invention, by suppressing the condensation of the plasticizer, it is possible to suppress the contamination on the film by the condensation liquid, the drying, the contamination of the wall in the heat correction process, etc. Can be reduced.

Schematic diagram of an apparatus to which the present invention is applied Schematic diagram of the drying process section Schematic diagram of cleaning equipment Main section schematic cross-sectional view of winding device Enlarged cross section of web (film) Schematic cross-sectional view of the core and film former Outline side view of winding device Schematic front view showing the connection of the film to the core Schematic front view showing the connection of the film to the core Schematic diagram showing a conventional device

A method for producing a film according to the present invention will be described with reference to the accompanying drawings. In addition, the reference invention is also described.
FIG. 1 schematically shows an apparatus for carrying out the method for producing a film according to the present invention, and the basic configuration is the same as that of the conventional solution casting film forming apparatus described according to FIG.

  A characteristic point of the apparatus for carrying out the present invention is that the apparatus and equipment for various points presented as problems to be solved by the invention are provided, and is as follows.

  First, the apparatus and apparatus for the problem relating to the roll-up of the product is embodied in the embossing device 30 and the winding device 70, and secondly, the adjustment of the dope for charging and discharging. And thirdly, the cleaning of the film surface is embodied in the cleaning device 50, and fourthly, the plasticizer in the drying or heat straightening process is provided. Concerning equipment contamination due to evaporation / condensation, it is embodied in a drying device 40 and a heat straightening device (including a cooling means) 60. Hereinafter, specific description will be given sequentially.

The solution of the problem regarding the first film winding will be described.
The film to be handled is a cellulose acylate film having a thickness of 20 to 85 μm.

The embossing will be described.
The film that has passed through the drying device 40 and, if necessary, the heat straightening device 60 is subjected to processing for forming the emboss 31 by the embossing device 30 in the previous stage of introduction into the winding process. As the embossing apparatus 30, an apparatus described in JP-A-63-74850 can be used.

  The emboss 31 is formed as shown in FIG. That is, the height H (μm) of the emboss 31 is set in the range of 0.05 to 0.3 of the film thickness T, and the width W is set in the range of 0.005 to 0.02 of the film width L. For example, when the film thickness is 40 μm and the film width is 100 cm, the thickness of the emboss 31 is set to 2 to 12 μm and the emboss width is set to 5 to 30 mm. The relationship with the touch roll 72 will be described later.

  As shown in FIG. 5-B, the emboss 31 may be formed on both sides of the film. In this case, the height H1 + H2 (μm) of the emboss 31 is set in the range of 0.05 to 0.3 of the film thickness T, and the width W is set in the range of 0.005 to 0.02 of the film width L. For example, when the film thickness is 40 μm, the height H1 + H2 (μm) of the emboss 31 is set to 2 to 12 μm. The emboss width is set to 5 to 30 mm.

  As for the lower limit of the embossing height, it is necessary to prevent partial uneven adhesion between the films. On the other hand, since the embossing is too high if the upper limit is higher than this, the rolled product form becomes a polygonal shape like the back of a horse. This is because it deforms and induces a failure.

  As for the width of the emboss, the embossed part will eventually become a loss part, so we want to reduce it. For example, when the film thickness is reduced from 80 μm to 40 μm, the frictional force between the film and the roll is 50 μm. It became clear that the grip force decreased extremely at the boundary, and when the film forming speed was further increased to 30 m / min or more, the friction force between the film and the roll was extremely reduced especially at 50 m / min or more. It has been found. For this reason, the emboss width is the minimum necessary for suppressing slippage of the film, particularly when a thin film of 50 μm or less is formed at a high speed of 50 m / min or more. However, it is also linked to the height of the above-mentioned embossing, and the embossing height × embossing width for clearing all of the pyramid shape, horse back, polygonal shape, and winding failure are determined.

The emboss 31 can be arranged not only at both ends of the film but also at the central portion.
About connecting the end of the film to the core:
In order to take up the film, it is first necessary to connect the leading end to the core 71. The configuration will be described with reference to FIGS.

  The mode shown in FIG. 8 is a mode in which the double-sided adhesive tape 75 is disposed over substantially the entire length of the core 71. In this embodiment, a double-sided adhesive tape 75 having a film thickness (paste thickening) of 20 to 55 μm and a width of 5 to 50 mm is applied to the entire surface in the core width direction to adhere the film to the core. The length of the double-sided adhesive tape 75 is set to a film width ± 50 mm.

  The tape 75 for adhering the web to the core may be a method of adhering the web and the core with a single-sided adhesive tape instead of the double-sided adhesive tape.

  In the embodiment shown in FIG. 9-A, a double-sided adhesive tape 75 having a width of 5 to 50 mm and a length of 10 to 50 cm is attached to one end of the core 71 at a position on one emboss 31, Just connect. In this embodiment, the leading edge of the film connected to the core 71 is cut obliquely in the range of θ = 10 to 60 degrees.

  FIG. 9B is an aspect given as a comparative example, in which a double-sided adhesive tape 75 is disposed only at the center of the core 71. A double-sided adhesive tape 75 having a width of 5 to 50 mm and a length of 10 to 50 cm was used. Moreover, the tip of the film was cut into a reverse parabola.

  For example, by reducing the film thickness from 80 μm film to 40 μm, the tape transfer to the film by the winding core tape has increased to 3 times more than expected. By reducing the tape thickness from the conventional 100 μm thickness to 20 to 55 μm, the transfer of the winding core tape can be performed with the conventional 80 μm film even if the 80 μm thickness film is reduced to 40 μm. It was found that the number of tapes was reduced more than the 100-thick tape was used, leading to loss reduction.

  Further, it was found that the transfer distance of the tape is drastically reduced by changing to the present system described here as compared with the film setting method of the comparative example. In particular, in the method of setting on one-side embossing, there is almost no loss due to this tape transfer. Even with the method of tape setting on a horizontal straight line, it was possible to keep it within the conventional loss due to the tape thinning.

  As shown in FIG. 4, the film is wound around the core 71 under pressing by the touch roll 72, but the pressing by the touch roll 72 is performed only on the emboss 31 portion (the emboss 31 of the emboss 31). There is a gap between the non-existing film surface and the touch roll 72).

  The air conditioning / atmosphere of the winding unit is set to a temperature of 20 to 45 ° C. and a humidity of 40 to 80% RH.

  Winding is performed so that the winding tension and the touch roll pressing force at the start of initial winding satisfy the following conditions.

  280 N / m width> Only the embossed part is wound so that the pressing force of the touch roll winding + winding initial tension> 60 N / m width.

With respect to the winding condition range of 280 N / m or more, the radial pressure applied to the embossed portion is too large due to the tension during winding and the pressing force of the touch roll. This is because when the film is unwound, the film peeling charge amount is too large, and the film charge amount becomes ± 2 KV or more, thereby inducing uneven coating. On the other hand, at 60 N / m or less, the take-up tension is too weak, especially when the take-up is longer than 2000 m, and the product rolls off when transporting the finished product roll, or unwinds due to the take-out tension at the time of re-feeding. .

  The pressing pressure of the touch roll 72 is monitored by installing a pressing pressure detector, and is set to 3 to 100 N / m width.

  As a pressing means of the touch roll 72, for example, a double-acting low friction cylinder or a servo motor is used to apply tension feedback.

  Press so that it can be controlled independently from both sides. It is preferable to measure the pressure on both sides with a pressure detector.

  The tension at the initial stage of winding is set to a low tension such as 60 to 180 N / m width.

  The shape of the touch roll 72 is a flat roll that contacts the entire width of the film at the beginning of winding, and is a roll that substantially contacts only the embossed portion by embossing. Alternatively, only the embossing may be contacted, but in this case, if the film width changes, it is necessary to shift the touch roll position in accordance with the embossing position.

  To control the tension, a taper tension setting, a function control tension setting or the like is used. The means / method may be a known technique.

  As described above, the embossing width is set to 5 to 30 mm, and it is preferable that the roll width = film width + (0 to +400) mm with a full width flat roll. Or it is preferable to set it as 10-40 mm as a contact width with the roll 72 touched only by an embossed part.

  The material of the touch roll 72 is metal or hard synthetic resin. The position to be touched is preferably the position immediately after the tangent line where the film contacts the product roll.

  The direction in which the touch roll 72 moves as it rolls up is more preferably the normal direction from the winding core.

  It is preferable to perform winding by setting the control of the edge point control (EPC) of the winding unit to be fixed automatically from 0 to 5 seconds before the winding end and 0 to 5 seconds after the winding start. .

  Next, the winding shape without slack will be described.

  As shown in FIG. 6, the winding diameter difference between the upper and lower ends of the core 71 is (Y1−X1) <5 mm, and / or the left / right difference in the core lowering winding diameter is (Y2−Y1) <5 mm. Take up. In the drawing, the case where the winding diameter difference or the left / right difference is zero is indicated by an imaginary line.

  In addition, said numerical value is a case where the product roll diameter at the time of winding up assumes 1000 mm or less. The above numerical values are experimentally determined according to the difference in the rolled diameter.

The reason for making it within 5 mm is that, as a result of diligent study, if the difference in winding diameter between the upper and lower ends exceeds 5 mm, the winding itself is in a loosely wound state, causing a winding slip during transportation of the product roll and causing loss. is there. Also, if the difference between the left and right core winding diameters is within 5 mm, the gap between the films will increase, and polygonal or horse spine failure will start to occur, and the radius will be smaller. This is because the radial direction stress is biased, so that peeling electrification at the embossed portion is increased at the time of re-feeding, and application unevenness due to charging is induced at the time of functional film coating. As a method of setting the difference in winding diameter between the upper and lower ends within 5 mm, the initial winding tension and the embossing touch pressing force are within the above-mentioned ranges, while the adjustment method is set so that the left-right difference of the core lower winding diameter is within 5 mm. The adjustment is performed by adjusting the left and right emboss thickness or adjusting the left and right touch roll pressing force.

  In order to form the winding diameter difference or the left / right difference as described above, the left / right contact pressure of the touch roll 72 with respect to the emboss 31 is adjusted. The touch roll pressure is detected by measuring means with left and right winding diameters installed on the left and right, for example, an optical displacement measuring instrument, or measured by a measure after winding, and the difference between the left and right winding diameters is calculated by the above formula. Adjust the pressing pressure to satisfy Therefore, the left and right pressing pressures of the touch roll 72 can be controlled independently.

(Radius under the core-Radius on the core) <5mm
In order to wind up so that it may satisfy | fill, it is necessary to wind up in the range with which the following winding hardness is satisfy | filled.

The winding hardness at the time of winding will be described.
Winding is performed so that (winding hardness of 31 parts of embossed-winding hardness of the middle position from the film edge to the center) <170.

  This is because when the hardness is 170 or more, the adhesion strength of the embossed portion is too large, and when the product roll is re-drawn, the peel charge amount is too high and the above-mentioned film charge amount cannot be within ± 2 KV. Moreover, it is because the winding state of the original winding intermediate part is a cover state, and the product roll causes a polygonal shape failure.

  Considering environmental considerations, when thinning from a conventional 80 μm film to a half-thickness of 40 μm, the winding diameter at the time of winding is the same as that of the conventional 80 μm film from the viewpoint of production efficiency. It is important to manage the above-mentioned emboss thickness, emboss width, take-up tension, touch pressing force, winding diameter, and winding hardness within the specified range. It becomes.

  The hardness can be measured according to a JIS standard viscous hardness tester or Swiss, PROCEQ S.H. A. An electronic film hardness tester, an echo chip, or a Paro tester 2 manufactured by the company can be used. The impact device uses the D type.

The hardness value L is measured by the rebound speed V / the striking speed V ₀ . The repulsion speed V is the rebound speed from the impact body specimen, and the impact speed V ₀ is the impact speed from the impact body specimen, and the average value of 10-point measurement was calculated. In addition, since the hardness of the central part has a large variation in the hardness measurement point in the original winding, the hardness was measured at the upper surface of the embossed part and the intermediate part between the embossed part and the central part.

  Regarding the second charging and static elimination, a known method can be used without any particular limitation for the dope adjustment for antistatic.

  Next, according to FIG. 7, the static elimination means arrange | positioned at the winding apparatus 70 is demonstrated. A static eliminator 74 is installed before winding and immediately after the winding unit. In particular, it is preferable to install the static eliminator 74 </ b> A at a position to be wound in the winding source winding tangent.

The static eliminator 74 can be configured to apply a reverse potential by a static eliminator or a forced charging device at the time of winding so that the charging potential when the original winding is redrawn is <± 2 KV. Further, it is possible to adopt a configuration in which static elimination is performed by a static eliminator that is alternately converted between positive and negative at 1 to 150 Hz.

  Instead of the static eliminator 74 described above, an ionizer or a static eliminator that generates ion wind can be used.

  Ionizer static elimination is performed by blowing ion wind onto the web fed from the embossing device 30 through the guide roller 73 to the core 71. The ion wind is generated by the static eliminator 74. As the static eliminator 74, a known one can be used without limitation.

  When the film roll is re-drawn, if the film charge is ± 2 KV or more, uneven coating may be induced when the functional film is applied. To prevent this, slow power is required during film winding. It becomes. In particular, when pursuing a thin film and high speed, film peeling electrification at the time of re-feeding becomes high, so that slow charging during film formation is essential.

  Next, regarding the reduction of the charge amount, the reduction of the peeling charge when the original roll product is re-drawn can be dealt with by adding a matting agent and reducing the contact area between the film surfaces.

The cleaning of the third film surface will be described with reference to FIG.
The cleaning device 50 is disposed in the front and / or rear of the drying device and / or the heat correction device 60, and applies ultrasonic vibrations to the film by the cleaning device 51 on the web in the middle of conveyance and blows high-pressure air on the surface. It applies and blows off the adhering matter and sucks it to remove the adhering dust. In addition, the cleaning means to arrange | position may be single and may be two or more.

  As cleaning means, methods other than vibration / high-pressure air supply / suction method, flame treatment (corona treatment, plasma treatment) method, adhesive roll installation method, etc. are used without any particular limitation. be able to.

  Since adhesion of dust or the like to the web is often due to the action of static electricity, it is preferable to remove static electricity from the web by disposing a static elimination means, for example, a static elimination bar 52 in front of the cleaning means 51 described above. As the static elimination bar 52, a well-known thing can be used without a special restriction | limiting.

  Next, a description will be given of how to condense the plasticizer. First, a configuration for preventing contamination of the equipment due to the evaporation / condensation of the plasticizer in the drying / thermal correction process will be described.

As a measure to suppress the phenomenon that the plasticizer evaporates and condenses on the rolls and wall surfaces in the drying / correction process where high temperature is applied, it is supported by injecting a certain amount or more of fresh air with respect to the supply air volume per unit time. Then, the amount of fresh air supply, to set at 5% to 50% of the total feed air flow.

  The reason why the fresh air supply amount is set to 5% to 50% is that if the amount is less than 5%, the amount of fresh air is too small to suppress the plasticizer condensation. If the amount exceeds 50%, the amount of fresh air is large. This is because it is an optimum range in which waste is increased in running cost.

In addition to the above measures, for example, the following configuration can be adopted. First, a configuration in which a part of the air in the drying / correction process chamber is circulated and the plasticizer is forcibly removed by passing it through a cooler coil or the like and then raised to a specified temperature with a heater. A configuration in which the temperature of the portion in contact with the metal surface is increased, for example, a configuration in which the temperature of the portion in contact with the metal surface is increased by a steam / surface heater or the like. Third, fresh air is supplied to lower the vapor pressure of the plasticizer on the roll surface. As a means for supplying fresh air, a configuration in which a slit is provided in the width direction in the vicinity of the roll, air air is supplied from the punch plate box, and the air velocity distribution of the supplied air is suppressed is used. Is not to be done.

  The temperature of the film when the film is taken out from the correction process chamber or the cooling process is preferably 60 ° C. or less.

  This is because, when the straightening and cooling process box is carried out at a temperature exceeding 60 ° C., the plasticizer is still condensed.

  Prevention of charging by adding a matting agent can be achieved by forming a film with a dope having a matting agent added to the uppermost layer and winding the film.

Examples of the reference invention of the present invention will be described below together with comparative examples.
Reference Example 1
Winding was performed by the apparatus shown in FIGS. At the time of winding, an embossed touch roll is used. This touch roll is a touch roll that presses the entire film, but basically, only the embossed portion is lightly pressed.

  The thickness of the TAC film was set to 40 μm, and the thickness of the emboss was set to 5 μm. A double-sided adhesive tape with a thickness of 40 μm and a width of 30 mm is bonded to only one embossed part with a length of 100 mm on the winding core, the web is fixed, the initial winding tension is 160 N / m, the taper is 50%, and the pressing pressure is The left and right gauge was set to 20N. The film was wound up under the above conditions. The results are shown in Table 1.

Comparative Example 1
Winding was performed by the apparatus shown in FIGS. The film was wound under the same conditions as in Reference Example 1 except that the initial winding tension was set to 250 N / m. The results are shown in Table 1.

Comparative Example 2
Winding was performed by the apparatus shown in FIGS. The film was wound under the same conditions as in Reference Example 1 except that the initial winding tension was set to 100 N / m (however, the touch roll was not performed). The results are shown in Table 1.

Comparative Example 3
Basically, the film was wound by the apparatus shown in FIGS. 1 to 8, but the thickness of the embossment was 13 μm except that the touch roll having the convex roll portion that contacted only the embossed portion of the film was used. The film was wound under the same conditions as in Reference Example 1 except that the initial winding tension was set at 180 N / m. The results are shown in Table 1.

Note 1: Horse back failure = deformation deformation of horse back due to loose winding Note 2: Polygon failure = polygonal deformation failure due to loose winding Note 3: Each evaluation is indicated by the following symbols.
○: No failure.

Δ: There is no problem in practical use, but a failure is observed.
×: There is a practical failure.

10-Storage tank 11-Dope inlet 12-Additive inlet 13-Insulation jacket 14-Discharge port 15-Gear pump 16-Pressure die 17-Support 18-Release point 19-Web 20-Tenter 21-Drying device 22 -Winding device 30-Embossing device 31-Embossing 40-Drying device 50-Cleaning device 51-Cleaning means 52-Static elimination bar 60-Thermal straightening device 70-Winding device 71-Core (core)
72-touch roll 73-guide roller 74-static eliminator 75-double-sided adhesive tape

Claims (2)

In the method for producing a cellulose acylate film by a solution casting film forming method, a drying and / or heat straightening step is carried out when the web peeled from the casting support is dried and heat-corrected as necessary and wound on a core. web by arranging the means for removing the plasticizer evaporates during winding gastric row, means for removing the plasticizer, of the total feed air flow in the drying and / or heat straightening process 5% to 50% of A method for producing a cellulose acylate film, which is a means for adding fresh air . The method for producing a cellulose acylate film according to claim 1, wherein the thickness of the cellulose acylate fill is 20 to 85 µm.

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