JP4082116B2 - Film manufacturing method - Google Patents

Description

表１に示すように、実施例１、２では、皺状変形群が検出されず、良好な平面性であった。一方、比較例においては、皺状変形群が検出され、特に４０ｍ／分以上で製造した比較例１は使用に耐えないものであった。
【００３８】
【発明の効果】
以上説明したように本発明に係るフィルム製造方法によれば、幅方向の中央部が一定の径で形成されるとともに、その中央部よりも端部が大きな径で形成されている剥離ロールを接触させるので、剥離直後のフィルムを安定させることができる。これにより、４０ｍ／分以上の製造速度においても高品質のフィルムを製造することが可能になる。
【図面の簡単な説明】
【図１】本発明に係るフィルム製造装置を示す構成図
【図２】剥離ロールを示す正面図
【図３】図２と異なる剥離ロールの特徴部分を示す正面図
【図４】図２と異なる剥離ロールを示す正面図
【図５】従来方法で製造したフィルムを示す図
【符号の説明】
１０…フィルム製造装置、１２…バンドゾーン、１４…乾燥ゾーン、１６…支持ローラ、１８…流延バンド、２０…流延ダイ、２２…フィルム、２４…剥離ロール、２６…ガイドロール、３０…テンター乾燥装置、３２…ローラ、３４…巻き取り機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film manufacturing method, and more particularly to a film manufacturing method for manufacturing a cellulose ester film by a solution casting method.
[0002]
[Prior art]
Cellulose ester films, particularly cellulose acetate films, are widely used for electronic display applications, photographic support applications, and other optical applications. Such a cellulose ester film is generally produced by a solution casting method.
[0003]
In the solution casting method, cellulose ester is first dissolved in a solvent together with a plasticizer, UV absorber, slip agent, and other additives to form a concentrated solution (hereinafter referred to as a dope), and this dope is endless such as a band or a drum. A film is produced by casting on a support and peeling off from the support where the cast dope has self-supporting property and drying. In this solution casting method, it is important in terms of the quality of the film product to stabilize the film immediately after peeling from the support.
[0004]
Therefore, conventionally, the film immediately after peeling is stabilized by bringing a peeling roll into contact therewith. For example, Japanese Patent Laid-Open No. 2001-198933 describes a method in which a drum-shaped peeling roll whose roll diameter decreases toward the center is brought into contact with the film peeled from the support from the support side. According to this method, it is possible to prevent the both ends of the film immediately after peeling from being broken, and it is possible to stabilize the conveyance of the film.
[0005]
[Problems to be solved by the invention]
However, the solution casting method has a problem that the higher the film production rate, the more the amount of residual solvent immediately after peeling and the softer the film, so that the film becomes unstable. In particular, when the production speed exceeds 40 m / min, this phenomenon becomes remarkable, and there arises a problem that warp deformation occurs at the end in the width direction of the film immediately after peeling. This slip deformation is fixed on the peeling roll, and causes a deformation group of short ridges 1 shown in FIG.
[0006]
In addition, since the drum-shaped peeling roll described in Japanese Patent Application Laid-Open No. 2001-198933 has a complicated shape, it has a problem that it is very difficult to process with high accuracy and the processing cost is high. Further, when a drum-shaped peeling roll is used, since the peeling point at which the film peels from the support increases as it becomes the center, the center of the film becomes unstable and the film may not be manufactured.
[0007]
The present invention has been made in view of such circumstances, and it is possible to stably peel the cast dope from the support and to produce a high-quality film even when the production rate is 40 m / min or more. It aims at providing the film manufacturing method which can be manufactured.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 casts a solution of a polymer material on a support, peels the cast solution from the support as a film, and contacts the release roll. In the film manufacturing method, the peeling roll has a central portion in the width direction in the contact portion with the film having a constant diameter, and an end portion in the width direction in the contact portion is larger in diameter than the central portion. is formed, the width of the central portion is characterized in that the der 90% the width of the contact portion is, the production rate of the film is 40 m / min or more.
[0009]
According to the peeling roll of Claim 1, since the edge part of the width direction in the contact part with a film is formed with a larger diameter than a center part, it conveys while the film which contacted the peeling roll is pulled outside Is done. Thereby, the edge part of a film can be stabilized and it can prevent that a wrinkle generate | occur | produces in the edge part of a film. In addition, according to the first aspect of the present invention, since the central portion occupying 90% or more of the width dimension of the contact portion is formed with a constant diameter, the peeling state of the central portion of the film is stable. Thereby, since the whole film is stabilized, a high-quality film can be produced even at a production rate of 40 m / min or more.
[0010]
Since the peeling roll described above has a simple shape, it can be easily processed. Therefore, a peeling roll can be manufactured at low cost.
[0011]
Moreover, as for a peeling roll, it is preferable that the level | step difference formed between an edge part and a center part is 0.1 mm or more and 200 times or less of the dry thickness of a film. If the level difference is within this range, it is possible to reliably prevent wrinkles from occurring at the end of the film, and to cause new defects due to the level difference, for example, wrinkles at the center of the film. Can be prevented.
[0012]
Moreover, it is preferable to make a peeling roll contact the film surface on the opposite side to the side which was in contact with the support body. Since the film immediately after peeling is easily curled to the side that is in contact with the support, if the peeling roll having the above shape is brought into contact from the opposite side, the entire film is easily brought into contact with the peeling roll, thereby further stabilizing the film. be able to.
[0013]
According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a taper is formed between the central portion and the end portion. According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the peeling roll includes a cylindrical roll and two ring-shaped members that are externally fitted to the roll. It is characterized by that. The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the surface of the end portion is subjected to dimple processing or groove processing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of a film manufacturing method according to the present invention will be described below with reference to the accompanying drawings.
[0015]
FIG. 1 is a schematic view showing a film production apparatus 10 of the present invention.
[0016]
As shown in the figure, the film manufacturing apparatus 10 includes a band zone 12 and a drying zone 14.
[0017]
The band zone 12 is provided with a pair of support rollers 16, 16, a casting band (corresponding to a support) 18, and a casting die 20. At least one of the pair of support rollers 16 and 16 is connected to a driving device (not shown). The casting band 18 is formed endlessly with a stainless steel plate or the like, and is wound around the pair of support rollers 16 and 16. Therefore, by rotating the support roller 16, the casting band 18 can travel between the pair of support rollers 16 and 16.
[0018]
The casting die 20 is provided above the casting band 18, and a cellulose ester dope is supplied to the casting die 20. The dope is prepared, for example, by dissolving cellulose ester in a solvent together with a plasticizer, a UV absorber, a slip agent, and other additives, and is cast from the casting die 20 onto the casting band 18 at a constant thickness. The cast dope is transported together with the casting band 18, and the organic solvent evaporates from the surface opposite to the casting band 18 (hereinafter referred to as air surface) during the transport. When the dope has a self-supporting property, the film 22 is peeled off from the casting band 18.
[0019]
The peeled film 22 first comes into contact with a peeling roll (roll that first comes into contact with the peeled film 22) 24, and then comes into contact with guide rolls 26, 27, and 28 in order. At that time, the peeling roll 24 and the guide rolls 26 and 28 are in contact with the air surface, and the guide roll 27 is in contact with the surface that is in contact with the casting band 18 (hereinafter referred to as a support surface). The film 22 can be stabilized by bringing the peeling roll 24 and the guide rolls 26 to 28 into contact with each other as described above. The contacted film 22 is introduced into the tenter drying apparatus 30 and the end in the width direction is held by a clip or a pin. And it conveys and dries in the state to which tension | tensile_strength was provided.
[0020]
The film 22 dried by the tenter drying device 30 is sent to the drying zone 14. The inside of the drying zone 14 is controlled to a temperature range of 50 to 150 ° C., and the film 22 sent to the drying zone 14 is wound around a plurality of rollers 32, 32. The dried film 22 is taken up by a winder 34.
[0021]
In the above-described embodiment, the casting band 18 is used as a support, but a casting drum may be used. That is, the dope may be cast on the surface of the drum while rotating the drum whose surface is smoothed by chrome plating or the like.
[0022]
Next, the peeling roll 24 which is a characteristic part of the present invention will be described.
[0023]
As shown in FIG. 2, the peeling roll 24 includes a central portion 24 </ b> A in the width direction and end portions 24 </ b> B and 24 </ b> B provided on both outer sides thereof. The central portion 24A is formed with a constant diameter, and the end portion 24B is formed with a larger diameter than the central portion 24A. Therefore, a step is formed between the end portion 24B and the central portion 24A. If the size H is small, it is difficult to obtain the effect of preventing wrinkles due to the increase in the diameter of the end 24B. If the size H is large, there is a possibility that new wrinkles may occur due to the effect of the step. is there. Therefore, the step size H is preferably 0.1 mm or more and 200 times or less of the dry film thickness of the film 22, more preferably 0.5 mm or more and 100 times or less of the dry film pressure of the film 22. . The thickness of the film is not particularly limited, but it is preferable when the finished film thickness is 125 μm or less because the film rigidity is particularly low and deformation is easily fixed. The thickness of the film is more preferably 85 μm or less and more preferably 65 μm or less.
[0024]
It is preferable that a taper 24C having a predetermined angle (for example, 45 °) is provided between the central portion 24A and the end portion 24B, and the diameter of the peeling roll 24 is gradually changed. Thereby, it can prevent that the film 22 between 24 A of center parts and the edge part 24B bend | folds by stress concentration. The shape between the central portion 24A and the end portion 24 is not limited to the taper 24C, and may be an arc shape as shown in FIG. 3, for example. Moreover, the peeling roll 24 without the taper 24C between the center part 24A and the end part 24B may be used.
[0025]
The width dimension W1 of the central portion 24A is set to be 90% or more of W2 with respect to the width dimension W2 of the contact portion with which the film 22 contacts. Thereby, 90% or more of the film 22 is conveyed while contacting the central portion 24A. In addition, the width dimension W1 of the central portion 24A is more preferably 95% or more, and still more preferably 97% or more.
[0026]
The above-described peeling roll 24 is rotatably supported, and is rotated by being driven by contact with the film 22 being conveyed. In addition, it is preferable that the peeling roll 24 is rotationally driven by connecting a driving device (not shown) such as a motor to the peeling roll 24.
[0027]
Next, the operation of the peeling roll 24 configured as described above will be described.
[0028]
The dope cast on the casting band 18 is dried as the organic solvent in the dope evaporates from the air surface side of the film 22. Therefore, when the traveling speed of the casting band 18 is increased and the drying time is shortened, the amount of the solvent remaining in the film 22 increases, and the film 22 at the time of peeling becomes soft. For this reason, the film 22 at the time of peeling is unstable, and wrinkles are likely to occur at the ends. When the film 22 in this state is brought into contact with the peeling roll 24, the peripheral speed at the end 24 </ b> B of the peeling roll 24 is faster than that at the center, so that the film 22 is conveyed while being pulled outward. Thereby, the film 22 immediately after peeling can be stabilized, and especially the both ends can be stabilized. In addition, the edge part of the film 22 which contacted the edge part 24B is cut | disconnected by a post process as an ear | edge part, and is removed.
[0029]
Moreover, since the central part 24A is formed with a constant diameter in the peeling roll 24, the take-up speed of the central part of the film 22 that contacts the central part 24A does not slow down. Therefore, the central part of the film 22 immediately after peeling is stable. Further, since the width dimension W1 of the central portion 24A is 90% or more of the width dimension W2 of the contact portion, the film 22 has a portion to be a product (that is, an end portion of 10% or less cut as an ear portion in a later step) A very high quality can be obtained in the (excluding portion).
[0030]
Thus, if the peeling roll 24 of this Embodiment is used, the film 22 immediately after peeling can be stabilized. Therefore, a high-quality film 22 free from wrinkles can be produced even at a production rate of 40 m / min or more. The high-quality film 22 produced in this way can be preferably used for photographic supports and other general optical applications as well as electronic display applications.
[0031]
In addition, the peeling roll 24 in embodiment mentioned above may form the center part 24A and the edge part 24B integrally, or may form it by a separate member. For example, as shown in FIG. 4, the peeling roll may be formed by fitting ring-shaped members 38, 38 to a cylindrical roll 36. In this case, by adjusting the interval between the ring-shaped members 38, 38, the width dimension W1 of the central portion can be adjusted, and the film 22 having various width dimensions can be handled. Further, by attaching the ring-shaped member 38 having a different outer diameter size, the size H of the step between the central portion and the end portion can be easily changed. In place of the ring-shaped member 38, a tape may be overlapped and wound. In this case, the step size H can be easily changed by the number of windings of the tape.
[0032]
Moreover, the shape of the edge part 24B of the peeling roll 24 is not limited to embodiment mentioned above, What is necessary is just to protrude outside 24A of center parts. Therefore, the surface of the end portion 24B may be subjected to processing that increases friction with the film 22, for example, dimple processing or groove processing. Thereby, since the force with which the end 24B pulls the film 22 is increased, wrinkling of the film 22 can be more reliably prevented.
[0033]
In the embodiment described above, at least one of the guide rolls 26 to 28 may be formed in the same manner as the peeling roll 24. That is, the center part in the width direction that forms 90% or more of the contact part with the film 22 may be formed with a constant diameter, and the end parts on both sides thereof may be formed with a larger diameter than the center part. Thereby, the film 22 until it is introduced into the tenter drying apparatus 30 after peeling can be stabilized.
[0034]
In addition, it is preferable that the amount of residual solvents of the film 22 at the time of contacting the peeling roll 24 is 40-120 mass%, and this can improve the quality of the film 22 more.
[0035]
【Example】
92 parts by weight of dichloromethane for 100 parts by weight of solid content comprising 89.3% by weight of cellulose acetate (substitution degree 2.8), 7.1% by weight of triphenyl phosphate and 3.6% by weight of biphenyl diphenyl phosphate % And a mixed solvent consisting of 8% by weight of methanol was appropriately added, and dissolved by stirring to prepare a dope. The solid content concentration of the dope was 19.5%. This dope is filtered through a filter paper (# 63) manufactured by Toyo Filter Paper Co., Ltd., and further filtered through a sintered metal filter (06N manufactured by Nippon Seisen Co., Ltd., nominal pore diameter 10 μm), and further a mesh filter (Nihon Pole) The product was filtered through RM manufactured by Co., Ltd. (nominal pore diameter: 45 μm).
Example 1
The above dope was cast using the same film production apparatus as in FIG. Then, after the cast dope was dried with hot air until it had self-supporting properties, it was peeled off as a film, and this film was introduced into a tenter dryer through four rolls such as a peeling roll and a guide roll. At that time, the moving speed of the casting band was 45 m / min. Further, as the peeling roll, a tape having a stepped portion having a height of 1 mm was formed by overlappingly attaching a tape to both ends of the portion in contact with the film. Moreover, the edge part of the film was made to contact the edge part of a peeling roll 15 mm at a time. The width of the film on the peeling roll was about 1550 mm.
[0036]
The film introduced into the tenter dryer was sufficiently dried in a roll drying zone and wound up as a film. The film thickness was 79 μm. The finished film width was adjusted to 1336 mm by cutting off both ends in the process.
(Example 2)
A film was produced in the same manner as in Example 1 with a band moving speed of 35 m / min.
(Comparative Example 1)
A cylindrical roll (that is, a roll having a central portion and an end portion having the same diameter) was used as a peeling roll, and a film was produced in the same manner as in Example 1.
(Comparative Example 2)
A cylindrical roll (that is, a roll having a central portion and an end portion formed with the same diameter) was used as a peeling roll, and a film was produced in the same manner as in Example 2.
(Comparative Example 3)
A film having a concave shape (a shape having a smaller diameter toward the center) was used as a peeling roll, and a film was produced in the same manner as in Example 1. In Comparative Example 3, since the peeling point at which the film peeled from the casting band increased in the central portion in the width direction, it was difficult to maintain the process, and film production was stopped.
[0037]
The films of Examples 1 and 2 and Comparative Examples 1 and 2 produced as described above were spread on an inspection table covered with a black cloth, and the presence or absence of deformation under a fluorescent lamp was visually inspected. Then, the number of occurrences of sag deformation in the group was counted as a “sag-shaped deformation group” and evaluated. The results are shown in Table 1 below. In the determination of the same table, it was assumed that ○ was good, Δ was slightly defective, and X was defective.
[Table 1]

As shown in Table 1, in Examples 1 and 2, no hook-shaped deformation group was detected, and the flatness was good. On the other hand, in the comparative example, a saddle-shaped deformation group was detected, and in particular, Comparative Example 1 manufactured at 40 m / min or more was unusable.
[0038]
【The invention's effect】
As described above, according to the film manufacturing method of the present invention, the central part in the width direction is formed with a constant diameter, and the peeling roll whose end part is formed with a larger diameter than the central part is contacted. Therefore, the film immediately after peeling can be stabilized. This makes it possible to produce a high quality film even at a production speed of 40 m / min or more.
[Brief description of the drawings]
FIG. 1 is a structural view showing a film manufacturing apparatus according to the present invention. FIG. 2 is a front view showing a peeling roll. FIG. 3 is a front view showing a characteristic part of a peeling roll different from FIG. FIG. 5 is a front view showing a peeling roll. FIG. 5 is a diagram showing a film manufactured by a conventional method.
DESCRIPTION OF SYMBOLS 10 ... Film manufacturing apparatus, 12 ... Band zone, 14 ... Drying zone, 16 ... Support roller, 18 ... Casting band, 20 ... Casting die, 22 ... Film, 24 ... Peeling roll, 26 ... Guide roll, 30 ... Tenter Drying device, 32 ... roller, 34 ... winder

Claims (6)

In a film manufacturing method in which a solution of a polymer material is cast on a support, and the cast solution is peeled from the support as a film and brought into contact with a peeling roll.
In the peeling roll, the widthwise center portion of the contact portion with the film is formed with a constant diameter, and the widthwise end portion of the contact portion is formed with a larger diameter than the center portion. width parts are Ri der 90% of the width of the contact portion,
The method for producing a film, wherein a production rate of the film is 40 m / min or more .   2. The film manufacturing method according to claim 1, wherein a step formed between the end portion and the central portion is 0.1 mm or more and 200 times or less of a dry thickness of the film.   The film manufacturing method according to claim 1, wherein the peeling roll is in contact with a film surface opposite to the side in contact with the support. The film manufacturing method according to claim 1, wherein a taper is formed between the central portion and the end portion. 5. The film manufacturing method according to claim 1, wherein the peeling roll is configured by a cylindrical roll and two ring-shaped members that are externally fitted to the roll. 6. The film manufacturing method according to claim 1, wherein dimple processing or groove processing is performed on a surface of the end portion.

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