JP2001113546A - Method and apparatus for producing film, and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide film producing technique capable of stably and efficiently obtaining a film of high quality with a thickness of below 85 μm. SOLUTION: A method for producing a film with a thickness of below 85 μm by utilizing a solution casting method has a dope casting process for casting a dope being a raw material solution of the film on a support, a peeling process for peeling the web formed on the support by the dope casting process from the support, a drying process for drying the web peeled from the support by the peeling process while feeding the same through a plurality of feed rolls and a taking-up process for taking up the film obtained by drying the web in the drying process and, in the drying process, the web is dried so as to hold the elastic modulus of the web to 0.1 kgf/mm2 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing a film suitable as, for example, a protective film for a polarizing plate of a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display (LCD) has a low voltage and a low power consumption, can be directly connected to an IC circuit, and can be particularly thinned. Widely used as display devices for word processors, personal computers, and the like. This LCD basically has a structure in which polarizing plates are provided on both sides of a liquid crystal cell.

[0003] The above-mentioned polarizing plate has a property of transmitting only light having a polarization plane in a certain direction. Therefore, in the LCD, the polarizer plays an important role of visualizing a change in the orientation of the liquid crystal due to the electric field. That is, the performance of the LCD largely depends on the polarizing plate.
Here, a structure of a general polarizing plate is shown in FIG. In FIG. 12, reference numeral 31 denotes a polarizer, and a polarizer protective film 32 is laminated on both sides of the polarizer 31. By laminating a polarizing plate having such a configuration on a liquid crystal cell, the LCD is configured.

The polarizer 31 is obtained by adsorbing iodine or the like on a polymer film and stretching it. That is, after a solution called an H ink containing a dichroic substance (iodine) is wet-adsorbed to a polyvinyl alcohol film, the film is uniaxially stretched to orient the dichroic substance in one direction. It was done.

On the other hand, among the components of the polarizing plate, the polarizing plate protective film 32 is made of a cellulose resin, especially cellulose triacetate. Such a polarizing plate protective film 32 is generally manufactured by using a band casting type apparatus shown in FIG. That is, FIG.
In the band casting apparatus shown in FIG. 3, a casting die 34 is provided near a casting band 33 and
5, a drying unit 36 and a take-up roll 37 are provided. Then, after casting the dope from the casting die 34 into the casting band 33, the film (web) is peeled off by the peeling roll 35 and further dried completely by the roll drying unit 36, and then the film is wound up. It is configured to be wound by a roll 37.

Incidentally, the polarizing plate protective film 32 which is practically used has a relatively large thickness of 85 μm or more. However, recently, a thin polarizing plate protective film having a thickness of less than 85 μm has been increasingly required. However, it has been difficult to obtain a polarizing plate protective film having a thickness of less than 85 μm and a high quality by using a conventional band casting apparatus. In other words, when a thin polarizing plate protective film having a thickness of less than 85 μm is manufactured using a conventional band casting method apparatus, the surface of the obtained polarizing plate protective film may have fatal effects such as wrinkles, breaks, and scratches. Failure (failure) often occurred.

Accordingly, an object of the present invention is to provide a film manufacturing technique capable of stably and efficiently obtaining a high-quality film having a thickness of less than 85 μm. Another object is to provide a high-quality film having a thickness of less than 85 μm.

[0008]

An object of the present invention is to provide a method for producing a film having a thickness of less than 85 μm by using a solution casting method, wherein a dope which is a raw material solution of the film is provided on a support. A dope casting step of casting, a web formed on the support by the dope casting step, a peeling step of peeling the web from the support, and the web peeled from the support by the peeling step. The web includes a drying step of drying while being transported via a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step, wherein the drying step includes: The elastic modulus of the web is 0.1k
The problem is solved by a film manufacturing method characterized in that the web is dried so as to be maintained at gf / mm ² or more.

In the above method for producing a film,
In order to further improve the quality of the product, at least one step between the dope casting step and the peeling step, or between the peeling step and the drying step, or between the drying step and the winding step In the meantime, it is preferable to apply a reduced pressure treatment to the web. Further, the above-mentioned problem is a method for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope is formed by casting a dope, which is a raw material solution of the film, on a support. An elongation step, a stripping step of separating the web formed on the support by the dope casting step from the support, and a plurality of conveyances of the web separated from the support by the stripping step. A drying step of drying while transporting via a roll, and a winding step of winding a film obtained by drying the web by the drying step, acting on the web in the transport direction. Tension Tkgf / mm ² and elastic modulus Ykgf / m of the web
m ² satisfies the following formula: T ≦ 20Y (when 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (when 0.1 ≦ Y) The problem is solved by a film manufacturing method characterized in that the film is transported.

Another object of the present invention is to provide an apparatus for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope as a raw material solution of the film is cast on a support. Dope casting means, a web formed on the support by the dope casting means, a peeling means for peeling off the support, and the web was peeled from the support by the peeling means. A drying unit for drying the web while being transported through a plurality of transport rolls, and a winding unit for winding a film obtained by drying the web by the drying unit, By at least a part of the transport rolls provided in the drying means, the web,
The problem is solved by a film manufacturing apparatus characterized by being configured to be stretched in the width direction.

In this film manufacturing apparatus,
In order to further improve the quality of the product, the tension Tkgf / mm ² acting on the web along the web transport direction and the elastic modulus Ykgf / mm ^{2 of the} web are expressed by the following equation: T ≦ 20Y (where 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (when 0.1 ≦ Y), it is preferable that the web is conveyed.

Further, the above-mentioned object is to provide an apparatus for producing a film having a thickness of less than 85 μm, utilizing a solution casting method, wherein a dope as a raw material solution of the film is cast on a support. Dope casting means for doping, the web formed on the support by the dope casting means,
Peeling means for peeling off the support, drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls, and drying means for drying the web A winding unit for winding a film obtained by drying the web, and a tension acting on the web, which is provided in the middle of the web transport path, along the web transport direction. And a total of mechanical losses caused by rotational frictional resistance of a transport roll existing between the transport tension control means and the winding means, for a transport path length of the web of 200 m. And a film manufacturing apparatus characterized in that it is configured to be 5 kgf or less per 1 m of web width.

Another object of the present invention is to provide a method for producing a film having a thickness of less than 85 μm by using a solution casting method, wherein a dope as a raw material solution of the film is cast on a support. Dope casting step, a web formed on the support by the dope casting step, a separation step of separating the support from the support, and the web separated from the support by the separation step, A drying step of drying while being transported via a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step, wherein the web in the drying step, The contact pressure to the transfer rolls except for the drive rolls that generate the driving force is
The problem is solved by a film manufacturing method characterized by being 0.0001 to 0.5 kgf / cm ² .

Another object of the present invention is to provide a method for producing a film having a thickness of less than 85 μm by using a solution casting method, wherein a dope which is a raw material solution of the film is cast on a support. Dope casting step, a web formed on the support by the dope casting step, a peeling step of peeling from the support, and the web peeled from the support by the peeling step, A drying step of drying while being transported via a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step, wherein in the drying step, the transport rolls in 80 percent or more locations of all points that are present, and the web Zan溶W _s represented by × 100 (absolute dry weight of the residual in the web solvent weight / web), before And forming embracing angle theta of two perpendicular to each other that down the center of rotation of the conveyor the conveying roll from the portion which is tangent to the roll at the web, when the following relationship W _s> 30 is, 5 ° <θ ≦ 180 When 0 ≦ W _s ≦ 30, the problem is solved by a film manufacturing method characterized in that the web is transported so as to satisfy 5 ° ≦ θ ≦ 270 °.

Another object of the present invention is to provide an apparatus for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope as a raw material solution of the film is cast on a support. Dope casting means for doping, the web formed on the support by the dope casting means,
Peeling means for peeling off the support, drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls, and drying means for drying the web And a winding means for winding a film obtained by drying the web, and between the peeling means and the drying means and / or between the drying means and the winding means,
Tension control means for controlling the tension acting on the web is interposed along the transport direction of the web, and the difference between the tension acting on the web before and after the tension control means is a web width of 1 m. The above problem can be solved by a film manufacturing apparatus characterized in that the film manufacturing apparatus is configured to have a weight of 1 kgf or more.

In this film manufacturing apparatus,
In order to further improve the quality of the product, the tension control means includes a drive roll also serving as a transport roll as a component, and one or more drive rolls are provided per 500 m of a web transport path length. Preferably. Further, the above object is a method for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope flow for casting a dope as a raw material solution of the film on a support. An elongation step, a stripping step of separating the web formed on the support by the dope casting step from the support, and a plurality of conveyances of the web separated from the support by the stripping step. A drying step of drying while being transported through a roll, and a winding step of winding a film obtained by drying the web by the drying step, between the peeling step and the drying step, Alternatively, between the drying step and the winding step, or between the peeling step and the winding step, or during the drying step,
A tension control process is performed. In the tension control process, the tension acting on the web is controlled along the transport direction of the web such that the difference in tension before and after the tension control process is 1 kgf or more per 1 m of the web width. The problem is solved by a film manufacturing method characterized by the following.

Another object of the present invention is to provide a method for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope as a raw material solution of the film is cast on a support. Dope casting step, a web formed on the support by the dope casting step, a separation step of separating the support from the support, and the web separated from the support by the separation step, A drying step of drying while being transported through a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step, wherein the drying step comprises: What is dried by passing through a drying area controlled to a predetermined drying temperature,
The problem is solved by a film manufacturing method characterized in that the temperature difference inside the drying area is set to be 10% or less of the temperature of the low-temperature (or high-temperature) drying area.

In this method for producing a film,
In order to further improve the quality of the product, at the inlet portion for entering the web into the drying zone and / or at the outlet portion for discharging the web from within the drying zone,
It is preferable that air having a temperature within the temperature range of the drying region is supplied to the web in a curtain shape. The above problem is further solved by using a solution casting method and having a thickness of 85 μm.
An apparatus for producing a film having a thickness of less than m, comprising: a dope casting means for casting a dope as a raw material solution of the film on a support; and a dope casting means formed on the support by the dope casting means. A separating unit for separating the separated web from the support, and a drying unit for drying the web separated from the support by the separating unit while transporting the web through a plurality of transport rolls. And a winding means provided with a winding core for winding a film obtained by drying the web by the drying means, and a peripheral surface of the winding core provided in the winding means has A film manufacturing apparatus, wherein a step is formed along the rotation axis direction of the winding core, and a height dimension of a step surface in the step is equal to a thickness of the film. Therefore, it is resolved.

Another object of the present invention is to provide an apparatus for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope, which is a raw material solution for the film, is cast on a support. Dope casting means, and the web formed on the support by the dope casting means,
Peeling means for peeling off the support, drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls, and drying means for drying the web Winding means provided with a winding core for winding a film obtained by drying the web by the above, as a winding core provided in the winding means, in a state where the winding of the film is completed , [(The amount of deflection of the central portion in the longitudinal direction of the core / core diameter) × 100] is used.

Further, the above object is a method for producing a film having a thickness of less than 85 μm using a solution casting method, wherein a dope which is a raw material solution of the film is cast on a support. Dope casting step, a web formed on the support by the dope casting step, a separation step of separating the support from the support, and the web separated from the support by the separation step, A drying step of drying while being transported through a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step using a winding core, wherein the winding is performed. In the process, an index R represented by [thickness of wound film layer / (number of winding times × film thickness)]
Is solved by a film manufacturing method, wherein the film is wound around the winding core so that 1.0 ≦ R ≦ 1.3.

In the above-mentioned film manufacturing method,
Examples of the film to be produced include a film composed of a lower fatty acid ester. In the above-described film production apparatus, the film produced may be a film composed of a lower fatty acid ester. Furthermore, in the above-described film production method, the produced film may include a polarizing plate protective film.

Similarly, in the above-mentioned film manufacturing apparatus, a polarizing plate protective film can be mentioned as a film to be manufactured. The problem to be solved by the present invention was obtained by using the above-described film manufacturing method.
The problem is solved by a film having a thickness of less than 85 μm, wherein the difference between the maximum thickness of the smooth portion excluding the side edge portion to be embossed and the average thickness is 5 μm or less. .

Another problem to be solved by the present invention is that a film having a thickness of less than 85 μm, which is obtained by using the above-mentioned film manufacturing apparatus, except for a side edge portion to be embossed. The problem is solved by a film characterized in that the difference between the maximum thickness of the smooth portion and the average thickness is 5 μm or less.

That is, in the present invention, when producing a film having a thickness of less than 85 μm, the various techniques as described above were used, so that all the disadvantages of the prior art could be solved. More specifically, when producing a film using a solution casting method, a soft web containing a solvent is dried while being conveyed along a very long path, and is finally wound into a roll. . However, when a thin film having a thickness of less than 85 μm is manufactured using the prior art, the surface quality of the obtained film is significantly reduced due to various factors. This tendency becomes more pronounced as the film thickness decreases. Specifically, when a large transport tension acts on the highly residual web immediately after being peeled from the support, the web is easily stretched in the transport direction and wrinkles are generated on the surface. Also, during the conveyance, the web is also stretched by the conveyance tension, and wrinkles are formed on the surface. Further, depending on the shape of the transport roll and the angle between the portion before and after the return of the web folded by the transport roll, a force acting toward the center of the web along the width direction of the web acts. Sometimes. Naturally, also in this case, wrinkles and breaks occur on the surface of the web. In addition to these points, the prior art has the following problems. That is, the bending stiffness of the film sharply decreases in inverse proportion to the cube of its thickness. For this reason, the thickness is 85μ.
Thin films of less than m have significantly reduced stiffness, resulting in various problems. For example, a wound body obtained by winding a film into a roll shape, that is, a depression in the center of the original winding, a non-circular cross section, that is, a polygonal shape, and a problem such as generation of scratches caused by such a phenomenon have occurred. . In short, it has been extremely difficult to obtain a high-quality film having a thickness of less than 85 μm using the conventional film manufacturing technology.

However, the techniques of the present invention employing the various methods listed above solve all of the problems of the prior art. That is, when the web is peeled off from the support, or when the web is dried while being conveyed, and when it is wound into a roll, a highly residual web or a sufficiently dried web (film) is wrinkled or broken. Fatal defects such as scratches (failures) do not occur. As a result, a high-quality film having a thickness of less than 85 μm can be stably and efficiently obtained. And it becomes possible to provide a high quality film having a thickness of less than 85 μm.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A film manufacturing method described below as a first embodiment of the present invention uses a solution casting method and a film having a thickness of less than 85 μm (particularly a liquid crystal display member such as a polarizing plate protective film). A film having a thickness of less than 85 μm), and a dope casting step of casting a dope which is a raw material solution of the film on a support; A stripping step of separating the web formed on the support from the support, and drying the web separated from the support by the stripping step while transporting the web through a plurality of transport rolls A drying step, and a winding step of winding a film obtained by drying the web in the drying step, wherein the elastic modulus of the web is 0.1 k in the drying step. The method is characterized in that the web is dried so as to be maintained at gf / mm ² or more. In particular,
In this film manufacturing method, between the dope casting step and the peeling step, or between the peeling step and the drying step, or between at least one of the drying step and the winding step The web is subjected to a decompression treatment.

On the other hand, a film production method described below as a second embodiment of the present invention utilizes a solution casting method.
For producing a film having a thickness of less than 85 μm, a dope casting step of casting a dope, which is a raw material solution of the film, on a support, A peeling step of peeling the formed web from the support, and a drying step of drying the web peeled from the support by the peeling step while transporting the web through a plurality of transport rolls,
And a winding step of winding a film obtained by drying the web in the drying step, wherein a tension Tkgf / mm acting on the web in a transport direction thereof is provided.
² and the elastic modulus Ykgf / mm ^{2 of the} web satisfy the following equation: T ≦ 20Y (provided that 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (provided that 0.1 ≦ Y) The web is transported in a state satisfying (time).

The film production apparatus described below as a third embodiment of the present invention utilizes a solution casting method.
A dope casting means for casting a dope, which is a raw material solution of the film, on a support, for producing a film having a thickness of less than 85 μm; The web formed on the peeling means for peeling the web from the support, the web peeled from the support by the peeling means,
A drying unit for drying while being transported via a plurality of transport rolls, and a winding unit for winding a film obtained by drying the web by the drying unit, the drying unit includes: The web is configured to be pulled in the width direction by at least a part of the transport rolls provided. In particular, the film manufacturing apparatus of the present embodiment has a tension Tkgf / m acting on the web in the web transport direction.
m ² and the elastic modulus Ykgf / mm ^{2 of the} web satisfy the following equation: T ≦ 20Y (provided that 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (provided that 0.1 ≦ Y) The web is transported in a state satisfying (time).

Further, a film production apparatus described below as a fourth embodiment of the present invention utilizes a solution casting method.
A dope casting means for casting a dope, which is a raw material solution of the film, on a support, for producing a film having a thickness of less than 85 μm; The web formed on the peeling means for peeling the web from the support, the web peeled from the support by the peeling means,
A drying unit for drying while being transported through a plurality of transport rolls, a winding unit for winding a film obtained by drying the web by the drying unit, and in the middle of a transport path of the web. A transport tension control unit for controlling tension acting on the web along a transport direction of the web, the transport existing between the transport tension control unit and the winding unit. It is characterized in that the total mechanical loss caused by the rotational frictional resistance of the roll is 5 kgf or less per 1 m of web width per 200 m of the web transport path length.

The method for producing a film described below as a fifth embodiment of the present invention utilizes a solution casting method.
For producing a film having a thickness of less than 85 μm, a dope casting step of casting a dope, which is a raw material solution of the film, on a support, A peeling step of peeling the formed web from the support, and a drying step of drying the web peeled from the support by the peeling step while transporting the web through a plurality of transport rolls,
A winding step of winding a film obtained by drying the web by this drying step, comprising: The contact pressure is set to 0.
0001 to 0.5 kgf / cm ² .

A film production method described below as a sixth embodiment of the present invention is for producing a film having a thickness of less than 85 μm by using a solution casting method, and is provided on a support. A dope casting step of casting a dope that is a raw material solution of the film, a web formed on the support by the dope casting step, a stripping step of stripping the web from the support, and a stripping step. A drying step of drying the web separated from the support while transporting the web through a plurality of transport rolls, and a winding step of winding a film obtained by drying the web by the drying step. In the drying step, at least 80% of all the locations where the transport rolls are present, ((weight of residual solvent in web / absolute of web) And the web Zan溶W _s represented by燥重amount) × 100, wherein from the tangential and going on portions of the conveying roller and forms embracing angle θ of two perpendicular to each other that down the center of rotation of the conveyor rolls in the web When W _s > 30, the web is conveyed to satisfy 5 ° <θ ≦ 180 ° and when 0 ≦ W _s ≦ 30, 5 ° ≦ θ ≦ 270 °.

The film production apparatus described below as a seventh embodiment of the present invention utilizes a solution casting method.
A dope casting means for casting a dope, which is a raw material solution of the film, on a support, for producing a film having a thickness of less than 85 μm; The web formed on the peeling means for peeling the web from the support, the web peeled from the support by the peeling means,
A drying unit for drying while being transported via a plurality of transport rolls, and a winding unit for winding a film obtained by drying the web by the drying unit, comprising: Between the drying means and / or between the drying means and the winding means, a tension control means for controlling a tension acting on the web is provided along a transport direction of the web. And a difference in tension acting on the web before and after the tension control means is 1 kgf or more per 1 m of web width. In particular, in the present embodiment, the tension control means includes a drive roll also serving as a transport roll as a component, and the drive roll includes:
One or more webs are provided for every 500 m of web transport path length.

Further, the film manufacturing method according to the seventh embodiment of the present invention uses a solution casting method and has a thickness of 8 mm.
For producing films of less than 5 μm,
A dope casting step of casting a dope, which is a raw material solution of the film, on a support, and a peeling step of peeling the web formed on the support by the dope casting step from the support, A drying step of drying the web peeled from the support in the peeling step while being transported through a plurality of transport rolls, and a winding step of winding a film obtained by drying the web in the drying step And, between the peeling step and the drying step, or between the drying step and the winding step, or between the peeling step and the winding step, or During the drying step, a tension control process is performed, and the tension control process is performed so that a difference in tension before and after the tension control process is 1 kgf or more per 1 m of web width. , Along the conveying direction of the web,
It is characterized in that the tension acting on the web is controlled.

The method for producing a film described below as an eighth embodiment of the present invention utilizes a solution casting method.
For producing a film having a thickness of less than 85 μm, a dope casting step of casting a dope, which is a raw material solution of the film, on a support, A peeling step of peeling the formed web from the support, and a drying step of drying the web peeled from the support by the peeling step while transporting the web through a plurality of transport rolls,
A winding step of winding a film obtained by drying the web by the drying step, wherein the drying step is performed by passing the web through a drying area controlled at a predetermined drying temperature. Wherein the temperature difference inside the drying area is set to be 10% or less of the temperature of the low-temperature (or high-temperature) drying area. In particular, in this embodiment, at an inlet portion for allowing the web to enter the drying area and / or at an outlet portion for discharging the web from the drying area,
Air having a temperature within the temperature range of the drying area is supplied to the web in a curtain shape.

Further, a film manufacturing apparatus described below as a ninth embodiment of the present invention utilizes a solution casting method.
A dope casting means for casting a dope, which is a raw material solution of the film, on a support, for producing a film having a thickness of less than 85 μm; The web formed on the peeling means for peeling the web from the support, the web peeled from the support by the peeling means,
Drying means for drying while being transported via a plurality of transport rolls, and winding means having a winding core for winding a film obtained by drying the web by the drying means; A step is formed on the peripheral surface of the winding core provided in the winding means along the rotation axis direction of the winding core. It is characterized by being equal to the thickness of the film.

A film manufacturing apparatus described below as a tenth embodiment of the present invention is for manufacturing a film having a thickness of less than 85 μm using a solution casting method, and is provided on a support. A dope casting means for casting a dope, which is a raw material solution of the film, and a web formed on the support by the dope casting means,
Peeling means for peeling off the support, drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls, and drying means for drying the web A winding unit having a winding core for winding a film obtained by drying the web according to the above, wherein the winding of the film is completed as a winding core provided in the winding unit. The present invention is characterized in that a core having a core bending ratio represented by [(the amount of bending in the center in the longitudinal direction of the core / core diameter) × 100] of 5% or less is used.

The method for producing a film described below as an eleventh embodiment of the present invention is for producing a film having a thickness of less than 85 μm by using a solution casting method. A dope casting step of casting a dope that is a raw material solution of the film, a web formed on the support by the dope casting step, a stripping step of stripping the web from the support, and a stripping step. A drying step of drying the web peeled from the support while transporting the web through a plurality of transport rolls, and winding the film obtained by drying the web by the drying step using a winding core. Winding step, wherein the index R represented by [thickness of wound film layer / (number of winding times × film thickness)] is 1.0 ≦ R ≦ It is characterized by winding the film on the winding core so as to be .3.

The film to be produced by the above-mentioned film production method is a polarizing plate protective film made of a lower fatty acid ester. The film to be manufactured by the film manufacturing apparatus is also a polarizing plate protective film made of a lower fatty acid ester. Furthermore, the film described below as an embodiment of the present invention is a film having a thickness of less than 85 μm, obtained by using the above-described film manufacturing method or the above-described film manufacturing apparatus, and on the side to be embossed. The difference between the maximum thickness of the smooth portion excluding the edge portion and the average thickness is 5 μm or less.

Now, although the content partially overlaps with the above description,
The film targeted by the present invention is made of, for example, cellulose ester. In particular, it comprises a lower fatty acid ester of cellulose. Here, the lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms, for example, cellulose acetate such as cellulose diacetate and cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate protate. Mixed fatty acid esters such as pionate and cellulose acetate butyrate are exemplified. Among these, the most preferred lower fatty acid ester of cellulose is cellulose triacetate, particularly cellulose triacetate having an acetylation degree of 54 to 62% (more preferably 59 to 62%). More preferred is cellulose triacetate having a degree of polymerization of 250 to 400.

The film contains a matting agent such as fine particles of silicon oxide, if necessary, in addition to the cellulose ester. Further, the film is preferably 1
Contains one or more UV absorbers. The ultraviolet absorber has a wavelength of 370 n from the viewpoint of preventing deterioration of the liquid crystal.
It is preferable that the compound has excellent absorption capacity for ultraviolet light having a wavelength of 400 nm or less and has low absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Examples include oxybenzophenone-based compounds, benzotriazole-based compounds, salicylic acid ester-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, nickel complex-based compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole-based compounds and benzophenone-based compounds. Among them, benzotriazole-based compounds are most preferable because unnecessary coloring of cellulose ester is small.

The film preferably contains one or more plasticizers. For example, phosphate plasticizers such as triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, diethyl phthalate, dimethoxy ethyl phthalate, dimethyl phthalate, Phthalate plasticizers such as dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl Glycolic acid ester type plasticizers such as butyl glycolate and the like can be mentioned. Among them, phthalic acid ester type and glycolic acid ester type plasticizers are particularly preferable because they hardly cause hydrolysis of cellulose ester. In addition, the freezing point (the true freezing point described in Kyoritsu Shuppan's Dictionary of Chemistry) is 20.
It is preferable that a plasticizer having a temperature of not more than ° C is included. Such plasticizers include, for example, tricresyl phosphate,
Examples include cresyl phenyl phosphate, tributyl phosphate, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, triacetin, and ethyl phthalyl ethyl glycolate.

From the viewpoint of dimensional stability, the content of the plasticizer is preferably 1 to 10% by weight, more preferably 3 to 7% by weight, based on the cellulose ester. In addition, the flexibility of the cellulose ester film is improved, and the workability of the film (slitting or punching. If the workability is poor, the cut surface becomes saw-toothed, and a large amount of chips is generated.) , The liquid crystal display performance is deteriorated when the film adheres to the film), and therefore, it is preferable that the amount of the plasticizer having a freezing point of 20 ° C or lower, particularly 14 ° C or lower is large. From this viewpoint, all of the plasticizers have a freezing point of 20 ° C. or less, particularly 14 ° C.
The following may be used.

Examples of the solvent constituting the dope composition include alcohols (especially lower alcohols) such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and n-butanol, and cyclohexane, dioxane, methylene chloride and the like. Examples thereof include aliphatic hydrocarbons and chlorides. The ratio of the solvent is preferably about 70 to 95 wt% for methylene chloride and about 30 to 5 wt% for other solvents. On the other hand, the concentration of the cellulose ester is preferably about 10 to 50 wt%.

The heating temperature after the addition of the solvent is preferably a temperature not lower than the boiling point of the solvent used and within a range where the solution does not boil. Specifically, the temperature is set to 60 ° C. or higher, particularly 80 to 110 ° C. The pressure is determined so that the solution does not boil at the set temperature. After the dissolution, it is taken out of the container while cooling, or is taken out of the container by a pump or the like, cooled by a heat exchanger, and then subjected to filtration.

After filtering the dope composition in which the above-mentioned film constituting materials (cellulose ester, plasticizer, ultraviolet absorber, matting agent, etc.) are dissolved in a solvent, a film is formed by a solution casting method. A film of the present invention, having a thickness of 10 to 85 μm and made of a lower fatty acid ester as a raw material, is obtained. In the production of the film, for example, US Patents 2,492,978 and 2,73
9,070, 2,739,069, 2,49
No. 2,977, No. 2,336,310, No. 2,36
7,603, 2,607,704, British Patent 6
4,071 and 735,892, JP-B-45-90
No. 74, No. 49-4554, No. 49-5614, No. 60-27562, No. 61-39890, No. 62-
No. 4208 can be used.

However, when forming a film, it is essential to use a film manufacturing apparatus schematically shown in FIG. Hereinafter, the film manufacturing method according to the first embodiment of the present invention will be described in more detail with reference to FIG. The film manufacturing method according to the present embodiment (hereinafter, simply referred to as the present film manufacturing method) uses a solution casting method (particularly, a band casting method) and has a thickness of less than 85 μm, more specifically, a thickness of 20 μm.
This is for producing a film having a thickness of not less than μm and less than 85 μm, in particular, a polarizing plate protective film comprising a lower fatty acid ester (hereinafter also referred to as a film used for a liquid crystal display member).

Here, the structure of a film manufacturing apparatus used for carrying out the present film manufacturing method (hereinafter, simply referred to as the present film manufacturing apparatus) will be described. As can be seen from FIG. 1 showing the schematic structure of this film manufacturing apparatus,
Dope casting means 1, circulating casting band (support)
2, a peeling roll (peeling means) 3, at least one or more (here two) drying boxes (drying means) 4, 5,
The main components are a winding means 7 having a winding core 6 for winding the obtained film F, and a decompression box (decompression means) M provided between the peeling roll 3 and the drying box 4. .

The dope casting means 1 includes a tank 8 having a stirring function, a liquid feed pump 9, and a casting solution for casting a dope as a raw material solution of the film F on the casting band 2. It has a die 10. That is, the dope casting means 1 is capable of casting the dope in the tank 8 from the casting die 10 onto the casting band 2 by a predetermined amount. On the other hand, the casting band 2 on which the dope is cast is an endless belt that circulates and moves as described above.
It is stretched between 1a and 11b. Driving means (not shown) is connected to one of the drums 11a and 11b. By operating the driving means, the belt 2 circulates in the direction of the arrow in FIG. It has become.

The stripping roll 3 provided in the vicinity of the casting band 2 helps the web W formed on the surface of the casting band 2 by the dope casting means 1 to be separated from the casting band 2. I do. That is, the transport direction of the web W, which has not been sufficiently dried and is still in a soft state, is changed to the drying boxes 4 and 5 by the peeling tension and the action of the peeling roll 3.

The drying boxes 4 and 5 have the same structure. That is, a plurality of transport rolls 12 are provided above and below the inside thereof (the transport rolls 12 also exist before and after the drying boxes 4 and 5). Therefore,
The web W is in close contact with the peripheral surface of the transport roll 12,
In addition, the paper is conveyed while being sewn during that time. In addition, the drying boxes 4 and 5 are adapted to be able to introduce and discharge drying air, respectively.

The winding means 7 is for winding the film F obtained through the drying boxes 4 and 5, and has the winding core 6 on which the film F is directly wound as described above. That is, a driving unit (not shown) is connected to the winding core 6, and by operating the driving unit, the winding core 6 rotates to wind the film F at a constant speed. ing.

The decompression box M is for performing decompression processing on the web W, that is, for promoting drying of the web W. Therefore, the decompression box M is actually connected to a vacuum pump (not shown), and by operating the vacuum pump, the internal pressure can be reduced below the ambient pressure. Although the decompression box M is provided between the stripping roll 3 and the drying box 4 here, the dope casting means 1 and the stripping roll 3
Or between the drying box 5 and the winding means 7. In other words, the pressure reduction process for the web W can be performed not only between the peeling step and the drying step described below, but also between the dope casting step and the peeling step, or between the drying step and the winding step. May be.

Now, the present film manufacturing method using the above-described film manufacturing apparatus is performed in the following procedure. That is, first, a dope, which is a raw material solution of a film, is cast from the casting die 10 onto the casting band 2 (dope casting step). Next, the web W having a uniform thickness formed on the casting band 2 by the dope casting step is peeled off from the casting band 2 (peeling step), and the web W is passed through the decompression box M. And send it to drying boxes 4 and 5. That is, the web W is dried while being transported through the plurality of transport rolls 12 (drying step). Thereby, the web W becomes a film F having a thickness of less than 85 μm. Thereafter, the film F may be wound by the winding core 6 provided at the end of the production line (winding step), and finally, the film F becomes a winding roll (film winding body).

In the present embodiment, the web W is dried in the drying step so that the elastic modulus of the web W is maintained at 0.1 kgf / mm ² or more. Therefore, even when the thin film F having a thickness of less than 85 μm is manufactured, wrinkles do not occur during the transport of the web W. Therefore, by using this film production method, a high-quality film having a thickness of less than 85 μm, particularly a polarizing plate protective film composed of a lower fatty acid ester, can be stably produced.
It becomes possible to obtain efficiently.

Next, a second embodiment of the film production method according to the present invention will be described. However, the film manufacturing method of the present embodiment is the same as that of the first embodiment described above with respect to the basic process and the equipment used. Therefore, the following description is made again with reference to FIG. In this film manufacturing method, first, a dope is cast on the casting band 2 by a casting die 10.
Then, the web W thus formed on the casting band 2 is peeled from the casting band 2 (peeling step). Then, the web W peeled off from the casting band 2 in this peeling step is sent to the drying boxes 4 and 5, and dried while being transported through the plurality of transport rolls 12 (drying step). Thereafter, the film F obtained by drying the web W in the drying step may be wound by the winding core 6 provided at the end of the production line (winding step). This results in a thickness of 8
A roll of a thin film (polarizing plate protective film) F of less than 5 μm is obtained.

In the present embodiment, the tension Tkgf / mm ² acting on the web W in the transport direction is given by:
The elastic modulus Ykgf / mm ^{2 of the} web W is expressed by the following equation: T ≦ 20Y (when 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (when 0.1 ≦ Y) The web W is transported in a state of being filled. Therefore, even when the thin film F having a thickness of less than 85 μm is manufactured, wrinkles do not occur during the transport of the web W. Therefore, by using this film production method, it is possible to stably and efficiently obtain a high-quality film having a thickness of less than 85 μm, particularly a polarizing plate protective film made of a lower fatty acid ester.

Next, a film manufacturing apparatus according to a third embodiment of the present invention will be described. However, even in the film manufacturing apparatus of the present embodiment, the basic film forming process using the same is the same as in the first embodiment. Accordingly, in the following, FIG. 1 and FIG.
The following description will focus on the differences from the first embodiment. (Other embodiments described hereinafter will use the reference numerals given in FIG.
Only the differences from the embodiment will be described).

The present film manufacturing apparatus is also provided with a dope casting means 1, a circulating casting band (support) 2, a peeling roll (peeling means) 3, and two stages in front and rear along the transport direction. The main components are the drying boxes (drying means) 4 and 5 and the winding means 7 having the winding core 6 for winding the obtained film F. At least a part of the transport rolls 12 is provided with a mechanism for applying a pulling force to the web W in its own width direction by rotating the web W when transporting the web W. I have. For example, on the peripheral surface of the transport roll 12, one continuous spiral first groove 13 intersects with the first groove 13.
A single continuous spiral second groove 14 is also formed. That is, the transport roll 12 has a shape in which a plurality of V-shaped grooves having an opening angle θ are formed on the peripheral surface. Therefore, the web W transported in contact with the transport roll 12 is:
The first groove 13 and the second groove 14 cooperate to be pulled in their own width direction.

Further, in the present film manufacturing apparatus, the tension T acting on the web W along the transport direction of the web W
kgf / mm ² and the elastic modulus Ykgf / mm ^{2 of the} web W satisfy the following equation: T ≦ 20Y (when 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (provided that 0.1 ≦ (When Y) The web W is configured to be transported in a state where Therefore, even when the film manufacturing apparatus of the present embodiment is used, wrinkles do not occur during the transport of the web W (because even if wrinkles are formed, the web W can be immediately extended by the action of the V-shaped groove, and ), It is possible to stably and efficiently obtain a high-quality film having a thickness of less than 85 μm, particularly a polarizing plate protective film made of a lower fatty acid ester.

Next, a film manufacturing apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. 3 which shows a schematic configuration thereof (however, most of the reference numerals use those given in FIG. 1). . The present film manufacturing apparatus is also provided with dope casting means 1, a circulating casting band (support) 2, a peeling roll (peeling means) 3, and two stages of back and forth along the transport direction. Drying boxes (drying means) 4 and 5, winding core 6 for winding the obtained film F
And a winding means 7 provided with

In addition to the above components, the present film manufacturing apparatus includes a transport tension control means K for controlling the tension acting on the web W along the transport direction of the web W along the transport direction of the web W. (The position of the transport tension control means K is arbitrary). The total mechanical loss caused by the rotational frictional resistance of the transport roll 12 present between the transport tension control means K and the winding means 7 is 5 kgf per 1 m of web width per 200 m of transport path length of the web W. It is configured so that the following is true, in other words, the transport tension is not excessive.

Therefore, even in the film manufacturing apparatus of this embodiment, wrinkles do not occur during the conveyance of the web W, and a high-quality film having a thickness of less than 85 μm, particularly a polarizing plate protective film made of a lower fatty acid ester, is used. It can be obtained stably and efficiently. Next, a film manufacturing method according to a fifth embodiment of the present invention will be described.

The film manufacturing method of the present embodiment also includes a dope casting step, a peeling step, a drying step, and a winding step. The type in which the contact pressure of the web W in the drying step, in particular, the contact pressure of the web W with respect to the transport rolls 12 excluding the drive roll that generates the driving force, that is, the type in which the web W is passively rotated as the web W travels The contact pressure of the web W to the transport roll 12 is 0.0001 to
0.5 kgf / cm ² .

For this reason, in the film manufacturing apparatus of this embodiment, during the transport of the web W, the web W
It does not stick to the surface of. Therefore, no defects such as wrinkles are generated on the web W, and the thickness of the web W is 85 μm.
It is possible to stably and efficiently obtain a high-quality film of less than 3, especially a polarizing plate protective film comprising a lower fatty acid ester.

Next, a film manufacturing method according to a sixth embodiment of the present invention will be described with reference to FIG. The film manufacturing method of the present embodiment also includes a dope casting step, a peeling step, a drying step, and a winding step. In the drying step, at 80% or more of all the locations where the transport rolls 12 are present, the web residual solution represented by (weight of residual solvent in web W / absolute dry weight of web W) × 100 W _s and the holding angle θ between two perpendiculars lowered from the portion of the web W that is tangent to the transport roll 12 to the rotation center O of the transport roll 12.
(See FIG. 4), when the following relationship W _s > 30, the web W is conveyed so as to satisfy 5 ° ≦ θ ≦ 270 ° when 5 ° <θ ≦ 180 ° and 0 ≦ W _s ≦ 30. I have to.

Therefore, in the film manufacturing method of the present embodiment, no harmful force is exerted on the web W while the web W is being conveyed, especially the force along the width of the web W itself. Therefore, defects such as wrinkles and breaks do not occur in the web W, and a high-quality film having a thickness of less than 85 μm, in particular, a polarizing plate protective film made of a lower fatty acid ester can be stably and efficiently obtained. is there.

Next, a film manufacturing apparatus (film manufacturing method) according to a seventh embodiment of the present invention will be specifically described with reference to FIG. Regarding this film production equipment,
As main components, a dope casting means 1, a circulating casting band (support) 2, a peeling roll (peeling means) 3,
Drying boxes (drying means) 4 and 5 provided in two stages in front and rear along the transport direction, and winding means 7 having a winding core 6 for winding the obtained film F are provided.

Now, in addition to these components, in the present film manufacturing apparatus, between the peeling roll 3 and the drying box 4, between the drying box 4 and the drying box 5, and between the drying box 5 and the winding means 7, Any one of the places between
Alternatively, tension control means K for controlling the tension acting on the web W is interposed at a plurality of locations along the transport direction of the web W. The difference between the tension acting on the web W before and after the tension control means K is 1 kgf or more per 1 m of the web width.

On the other hand, the film manufacturing method of this embodiment using the film manufacturing apparatus having such a structure is also described as follows.
Generally, the method includes a dope casting step, a peeling step, a drying step, and a winding step. And furthermore, stripping roll 3
Between the drying box 4 and the drying box 5, and between the drying box 5 and the winding means 7 at one or a plurality of positions, using the tension control means K. Control processing is performed. That is, the tension acting on the web W is controlled along the transport direction of the web W so that the tension difference before and after the tension control processing is 1 kgf or more per 1 m of the web width.

In this embodiment, a pair of a drive roll also serving as a transport roll, that is, a drive roll, and a non-drive roll that sandwiches the web W in cooperation with the drive roll are main components of the tension control means K. . By the way,
In the present embodiment, the calculation is such that one or more drive rolls are provided per 500 m of the transport path length of the web W.

In the film manufacturing apparatus (film manufacturing method) configured as described above, the transport tension is made appropriate by the operation of the tension control means K, so that wrinkles do not occur during the transport of the web W. Therefore, a high-quality film having a thickness of less than 85 μm, in particular, a polarizing plate protective film made of a lower fatty acid ester can be stably and efficiently obtained.

For reference, as the tension control means K, besides the above-mentioned type (so-called nip roll type),
Various types can be adopted. For example, FIG. 5 shows a main part of tension control means configured to temporarily adsorb the web W to the roll surface by using a negative pressure and thereby control the tension. More specifically, the tension control means of the type shown in FIG. 5 includes a hollow roll 16 provided with a partition 15 therein and a vacuum pump (not shown) connected to the internal space of the roll 16. Main components. Among them, the roll 16 is a roll having an infinite number of fine holes formed on the peripheral surface (for example, an outer blade shape of an electric shaver) and is rotatable with respect to the internal partition 15 (partition). 15 is immobile). Therefore,
When the vacuum pump is operated, air is exhausted from the space above the partition 15, and the space becomes negative pressure. Therefore, the portion of the web W that contacts the roll 16 is adsorbed on the surface of the roll 16, and as a result, the tension difference before and after the tension control means is controlled to be optimal.
In FIG. 5, for convenience, the front end face of the roll 16 is opened to show the internal partition 15, but actually, a lid for closing the end face is provided on both the front side and the back side.

In addition, when adopting a form in which the web W is temporarily adsorbed to the roll surface by negative pressure as the tension control means, various types of rolls other than those having the above structure can be used. An example is the roll shown in FIGS. However, FIG. 6 is an external view of a roll of another embodiment, and FIG. 7 is a sectional view of a main part of the roll.

The roll 17 shown in FIG. 6 and FIG. 7 is also disposed in the middle of the production line and used for tension control as in the previous case. A plurality of grooves 18 are formed at predetermined intervals. As shown in FIG. 7, through holes 19 are formed in the groove 18 at predetermined intervals. In other words, the roll 17 has a structure in which the internal space and the groove 18 are connected by the through hole 19. Therefore, the tension control means using this roll 17 also
By operating the vacuum pump and making the internal space a negative pressure,
The web W can be adsorbed on the surface.

Further, as the tension control means, a means as shown in FIG. 8 can be used. That is, the tension control means does not use the clamping by the roll pair or the suction by the negative pressure, but controls the front and rear tensions by the plurality of movable clips 20 which grip the left and right edges of the web W. ing. More specifically, the movable clip 20 has a bifurcated distal end that grips the web W, and has a proximal end implanted on the endless belts 21 and 22. For the endless belt 21, the pulley 2
3 and a pair of pulleys (not shown), and for the endless belt 22, a pulley 24
And a pair of pulleys (not shown)
Each is stretched. Therefore, this pulley 2
By rotating the plates 3 and 24 in opposite directions, the web W whose left and right ends are gripped by the movable clip 20 is forcibly conveyed while receiving a tensile force in the width direction. Therefore, the continuity of the tension acting on the web W is optimal when the tension difference between before and after the tension control means is the same as in the case where the web is cut off at this position, and the web is sandwiched by the pair of rolls or the case where the web W is attracted to the roll surface. It is possible to control so that

Next, a film manufacturing method according to an eighth embodiment of the present invention will be specifically described with reference to FIG.
First, regarding the film manufacturing apparatus used in carrying out the present film manufacturing method, as can be seen from FIG. 9, the apparatus includes, as main components, dope casting means 1,
A circulating casting band (support) 2, a peeling roll (peeling means) 3, drying boxes (drying means) 4, 5 provided in two stages in front and rear along the transport direction, and winding the obtained film F. A winding means 7 having a winding core 6 to be taken is provided. Further, in addition to such components, the film manufacturing apparatus includes a plurality of air curtain forming means G. The air curtain forming means G is arranged at each of the entrance and exit of the drying box 4 and the entrance and exit of the drying box 5, or at either the entrance or the exit, and supplies air at a predetermined temperature to the web W in a curtain shape. I can do it.

The film manufacturing method of this embodiment using the film manufacturing apparatus having such a structure generally includes a dope casting step, a peeling step, a drying step, and a winding step. Of these, the drying process is performed by the web W
Is dried by passing it through a drying area, that is, drying boxes 4 and 5. In particular, in this embodiment, the temperature difference inside the box in each drying box,
At the entrance and / or exit of each drying box, air at a temperature within the temperature range in each drying box is supplied in a curtain shape to the running web W, so that the temperature in the low-temperature side (or high-temperature side) drying area is increased. 10% or less.

Therefore, in the above-mentioned film manufacturing method,
The drying process of the web W is performed very well. That is, the web W does not have defects such as wrinkles during the drying process. Therefore, it is possible to stably and efficiently obtain a high-quality film having a thickness of less than 85 μm, particularly a polarizing plate protective film made of a lower fatty acid ester. Next, a film manufacturing apparatus according to a ninth embodiment of the present invention will be specifically described with reference to FIG.

Also in the present film manufacturing apparatus, the dope casting means 1, the circulating casting band (support) 2, the peeling roll (peeling means) 3, and the two steps in the transport direction Drying boxes (drying means) 4 and 5 provided in the apparatus, and a winding core 6 for winding the obtained film F
And winding means 7 provided with Now, in the present embodiment, as the winding core 6 provided in the winding means 7, FIG.
The shape shown below is used. That is, a step 25 is formed on the peripheral surface of the winding core 6 along the direction of the rotation axis (indicated by N in FIG. 10), and
The height of the step surface 26 in the step 25 (see FIG. 10)
(Indicated by h in the drawing) is equal to the thickness of the film F to be wound.

Therefore, in this embodiment, the film F
At the start of winding, the thickness of its own can be completely offset. That is, the film F is wound around the winding core 6.
The resulting curved surface is very smooth. Therefore, unlike a case where a winding core having a mere round cross section is used, a trouble such that a step corresponding to the thickness of the film F is successively transferred does not occur. As a result, the thickness is 85μ.
m, in particular, a polarizing plate protective film comprising a lower fatty acid ester can be stably and efficiently obtained.

Next, a film manufacturing apparatus according to a tenth embodiment of the present invention will be specifically described with reference to FIG. The present film manufacturing apparatus is also provided with dope casting means 1, a circulating casting band (support) 2, a peeling roll (peeling means) 3, and two stages of back and forth along the transport direction. Drying box (drying means) 4,
5. It has a winding means 7 provided with a winding core 6 for winding the obtained film F. However, in the present embodiment, the winding core 6 is hollow.

In this embodiment, as the take-up core 6 provided in the take-up means 7, in the state where the winding of the film F is completed, [(the amount of deflection in the center in the longitudinal direction of the core / core diameter) × 100] Is used whose core deflection rate is 5% or less. Therefore, the central part of the roll (original roll) formed by winding the film F into a roll does not fall. Accordingly, defects such as scratches do not occur in the wound film F, and a high-quality film having a thickness of less than 85 μm, in particular, a polarizing plate protective film made of a lower fatty acid ester can be stably and efficiently obtained. It is.

The material constituting the winding core 6 includes, for example, metal such as stainless steel, bakelite, glass-wool-lined plastic, and ceramic. Next, a film manufacturing method according to an eleventh embodiment of the present invention will be specifically described with reference to FIG.

The film manufacturing method of this embodiment also includes a dope casting step, a peeling step, a drying step, and a winding step. In the winding step, in particular, the film F is adjusted so that the index R represented by [thickness of wound film layer / (number of winding times × film thickness)] satisfies 1.0 ≦ R ≦ 1.3. It is wound around the winding core 6. That is, the size obtained by subtracting the radius of the winding core 6 from the actual radius of the original winding is set to be 1.0 to 1.3 times the product of the number of windings of the film F and its thickness.

Therefore, the film roll is wound to a moderate hardness while maintaining a perfect circular shape. Therefore, the occurrence of defects such as scratches due to winding deviation is suppressed, and the thickness is reduced to 85%.
It is possible to stably and efficiently obtain a high-quality film having a thickness of less than μm, particularly a polarizing plate protective film comprising a lower fatty acid ester. Next, FIG. 11 shows a cross section (a cross section along the width direction) of a film obtained by using the film manufacturing technique of the above embodiment.

As can be seen from the figure, a film having a thickness of less than 85 μm, particularly a polarizing plate protective film made of a lower fatty acid ester, according to an embodiment of the present invention, has a side edge portion (see FIG. (Not shown), the difference between the maximum thickness t _max of the smooth portion and the average thickness t _avg is 5 μm or less. By the way, a liquid crystal display member comprising a film obtained by using the above film manufacturing technology as a constituent element,
For example, a polarizing plate is manufactured as follows.

That is, for example, a cellulose ester film obtained as described above and further subjected to an alkali treatment is attached to both surfaces of a polarizer having iodine or the like adsorbed and stretched on a polymer film using a completely saponified polyvinyl alcohol aqueous solution. Good. Instead of the alkali treatment, a method described in JP-A-6-94915 or JP-A-6-118232 may be used.

For reference, the “liquid crystal display member” in this specification is a member used for a liquid crystal display device. For example, in addition to the polarizing plate, a polarizing plate protective film, a retardation plate,
Examples include a reflection plate, a viewing angle improving film, an antiglare film, an antireflection film, an antistatic film, and the like. In particular, the technology of the present invention is particularly suitable for producing a polarizing plate protective film.

[0089]

EXAMPLES First, samples and evaluation methods used in the following examples will be described (basically common to almost all examples). The sample, i.e., the lower fatty acid ester film, was obtained using a dope consisting of 100 parts by weight of cellulose triacetate, 350 parts by weight of methylene chloride, and 12 parts by weight of ethanol and triphenyl phosphate. That is, this dope is cast from a casting die onto a mirror-finished casting band, and a dope film is formed thereon. Next, the dope film is peeled off from the casting band, and then passed through a plurality of drying zones to be sufficiently dried. The sample is obtained through such a process, and is finally wound on a winding core and provided as a roll.

Next, regarding the evaluation, this was performed by ranking the samples in five stages of A to E shown below. The sample used at this time had a width of 90c.
m and a length of 100 cm. On the other hand, the equipment used was such that five 50 W fluorescent lamps were arranged in parallel, and set at a height of about 1.5 m above the sample so as to illuminate the sample from a 45 ° angle. However, the quality of the film (the presence or absence of a defect) was determined by visually observing the film surface.

A: All five fluorescent lamps look straight. B: The fluorescent lamp appears to be partially bent. C: The fluorescent lamp appears to be bent as a whole. D: The fluorescent lamp looks large and undulating. E: The fluorescent lamp looks greatly bent, and fine undulation is also observed.

The evaluation of the original volume is based on another criterion,
That is, “○”, “△”, “×”, and “XX” were used.
The meaning of each symbol is as follows. ：: No defect was observed, indicating a normal state. Δ: When observed very carefully, slight defects are observed. ×: Defects are clearly observed.

XX: Defects are clearly observed, and the degree is extremely large. For reference, "residual film" in the following examples means the residual solvent ratio in the film. This film residual solution is calculated as follows. That is, first, a film (or web) extracted as a sample is weighed. Next, the sample was heated at 115 ° C. for 1 hour.
Heat and dry for 30 minutes, weigh again after cooling. When the film weight obtained by the previous weighing is α, and when the film weight obtained by the subsequent weighing is β,
The above-mentioned film residual γ is calculated by γ (%) = [(α−β) / β] × 100.

Example 1 When the residual film content of the film became 20% or less, the drying temperature was changed, thereby changing the elastic modulus of the subsequent web to produce films having different thicknesses. The conditions and results are as shown in Tables 1 and 2, respectively. Tables 1 and 2 also show comparative examples.

-Table 1-Drying temperature (° C) Lower limit of elastic modulus (kgf / mm ² ) Example 1 80 5.0 Comparative example 1 160 0.07-Table 2-Thickness 40 µm Thickness 60 µm Thickness 80 µm Example 1 A A A Comparative Example 1 EDD [Evaluation] Example 1 had extremely good surface quality, while Comparative Example 1 had many wrinkles in the transport direction and was poor in surface quality.

Example 2 Films having different thicknesses were manufactured under the conditions shown in Table 3. The results are as shown in Table 4. Tables 3 and 4 also show comparative examples. Here, “elastic modulus” in Table 3 is the elastic modulus of the web being conveyed, and “tension” is the tension acting on the web being conveyed (all units are kgf / mm ² ).

-Table 3-Film residual solution (%) Elastic modulus Tension Example 2 5 160 3.4 Comparative example 2 28 80 3.0-Table 4-Thickness 40 µm Thickness 60 µm Thickness 80 µm Example 2 A A A Comparative Example 2 E D D [Evaluation] Example 2 had extremely good surface quality, whereas Comparative Example 2 had many wrinkles in the transport direction and had poor surface quality.

Example 3 Films having different thicknesses were manufactured using a film manufacturing apparatus employing the transport rolls described in the third embodiment of the present invention. The results are as shown in Table 5. Table 5 also shows a comparative example (a film manufactured using a conventional apparatus).

Table 5: Thickness: 40 μm, Thickness: 60 μm, Thickness: 80 μm Example 3 AAA Comparative Example 3 DCC [Evaluation] Example 3 has no wrinkles or fixation and has extremely good surface quality. In contrast, Comparative Example 3 had many wrinkles in the transport direction and had poor surface quality.

Example 4 Films having different thicknesses were measured using a film manufacturing apparatus configured so that the total mechanical loss of the transport rolls was 1.8 kgf per 1 m of web width per 200 m of web transport path length. Was manufactured. The results are as shown in Table 6. In Table 6, the sum of the mechanical losses is 5.8 as a comparative example.
The results in the case of using the conventional device of kgf are also shown.

Table 6 Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 4 B AA Comparative Example 4 C C C [Evaluation] Had many wrinkles in the transport direction and the surface quality was poor.

Example 5 The contact pressure of the web with the transport roll was 0.1 kgf / cm ² and 0.2 kgf / cm 2
As No. ² , films having different thicknesses were produced. The results are as shown in Table 7 (the former is Example 5-1 and the latter is Example 5-2). Table 7 shows that the contact pressure was 0.6 kgf / cm ² and 0.8 kgf as comparative examples.
/ Cm ² are also shown (the former is Comparative Example 5-1 and the latter is Comparative Example 5-2).

-Table 7- Thickness: 40 μm Thickness: 60 μm Thickness: 80 μm Example 5-1 AAA Example 5-2 BB A Comparative Example 5-1 CCC Comparative Example 5-2 DCC [Evaluation The surface quality of Example 5 was extremely good, whereas the surface quality of Comparative Example 5 was poor.

Example 6 Films having different thicknesses were manufactured under the conditions shown in Table 8. The results are as shown in Table 9. Tables 8 and 9 also show comparative examples. In addition, in Table 8, the term "hugging angle" means an angle formed by two perpendiculars lowered from the tangent of the transport roll to the rotation center of the transport roll on the web.

-Table 8- Residual film holding angle (°) Example 6-1 Over 30% 10 Example 6-2 Over 30% 120 Example 6-3 30% or less 5 Example 6-4 30% or less 270 Comparative Example 6-1 Over 30% 3 Comparative Example 6-2 Over 30% 200 Comparative Example 6-3 30% or less 3 Comparative Example 6-4 30% or less 300 -Table 9- Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 6-1 A AA Example 6-2 BB A Example 6-3 BB A Example 6-4 BB B Comparative Example 6-1 Scratches Scratches Scratches Comparative Example 6-2 DC C Comparative Example 6-3 Scratched Scratched Scratched Comparative Example 6-4 DCC [Evaluation] Example 6 had extremely good surface quality, while Comparative Example 6 had many wrinkles in the transport direction. Also, many scratches and the like were observed, and the surface quality was poor.

Example 7 Films having different thicknesses were manufactured under the conditions shown in Table 10. Table 11 shows the results.
As shown in FIG. Tables 10 and 11 also show comparative examples. In Table 10, "presence / absence of tension control section" refers to presence / absence of a section in which the difference in tension acting on the web is controlled to be 1 kgf or more per 1 m of web width (in this case, two or more sections have "presence". "). On the other hand, the “drive roll usage ratio” is the number of drive rolls (= components of the tension control means) per 1000 m of web transport path length.

-Table 10-Presence or absence of tension control section Drive roll use ratio (book) Example 7-1 Yes 3 Example 7-2 Yes 2 Comparative example 7 No 0-Table 11-Thickness 40 µm Thickness 60 µm Thickness 80 μm Example 7-1 A AA Example 7-2 B AA Comparative Example 7 DCC [Evaluation] Example 7 has extremely good surface quality, whereas Comparative Example 7 has wrinkles in the transport direction. And the surface quality was poor.

Example 8 The temperature difference (temperature deviation) inside the drying area where the web was dried was ± 3% and ± 9%.
As films having different thicknesses. The results are as shown in Table 12 (the former is Example 8-1 and the latter is Example 8-2). Incidentally, the temperature deviation was adjusted by forming an air curtain at the entrance and exit of the drying box. The temperature deviation is obtained by measuring the temperature in the drying box every other minute for 30 minutes, and dividing the difference between the maximum value and the minimum value of the temperature by the average value. Table 12 shows the temperature deviation as ± 13 as a comparative example.
The results in the case of% are also shown.

Table 12- Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 8-1 A AA Example 8-2 BB A Comparative Example 8 CCC [Evaluation] Example 8 has extremely good surface quality. On the other hand, Comparative Example 8 had many wrinkles and poor surface quality.

Example 9 Films having different thicknesses were manufactured using the film manufacturing apparatus employing the winding core described in the ninth embodiment of the present invention. The results are as shown in Table 13. Table 13 also shows a comparative example (a film manufactured using a conventional apparatus). However, the "transfer mark" in Table 13 means a mark formed by successively transferring the steps at the beginning of film winding onto the film overlying it.

Table 13 Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 9 No Transfer Trace No Transfer Trace No Transfer Trace Comparative Example 9 With Transfer Trace With Transfer Trace [Evaluation] In contrast, the surface quality was extremely good, while Comparative Example 9 was 2
Transfer marks were formed up to the point of mm.

[Example 10] Films having different thicknesses were formed using a film manufacturing apparatus employing the take-up core (core deflection rate: 0.5%) described in the tenth embodiment of the present invention. Manufactured. The results are as shown in Tables 14 and 15. However, the winding core is made of SUS and has a diameter of 20 cm. The width of the wound film is 2 m, and the final thickness of the film layer formed by winding the film is 50 cm. Further, the winding tension is initially 20 kgf per 1 m of the film width, and finally the winding tension is 1 kg.
It was adjusted to be 0 kgf. After the winding of the film was completed, the core deflection was measured after the end of the wound core was placed on a gantry and stored for 30 days so that the horizontal state was maintained. For reference, the measurement of the bending ratio was performed by directly inserting a pair of bars arranged in parallel into a core hole (a hollow portion along the axial direction). In addition, the evaluation of the surface quality was performed at a position near 1 cm from the surface of the winding core, 25 cm.
A total of three locations including a nearby location and a location near 50 cm were measured. Tables 14 and 15 also show, as a comparative example, results of using a conventional device (a device employing a plastic winding core having a core deflection rate of 6.2%). However, the term "bent" in Table 14 means a deformation of the original winding obtained by winding a predetermined amount of the film around the winding core (inverted curved shape).

Table 14 Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 10 No Fold No Fold No Fold Comparative Example 10 Folded Folded Folded Table 15- Thickness 40 μm Thickness 60 μm Thickness 80 μm Example 10 A A A Comparative Example 10 EDC [Evaluation] In Example 10, there was no break in the original roll and the surface quality was extremely good, whereas in Comparative Example 10, the original roll was broken. The surface quality was also poor.

[Example 11] The film manufacturing method described in the eleventh embodiment of the present invention was used.
2 and 1.3 (by adjusting the winding tension)
Films of different thickness were produced. The results are as shown in Table 16 (the former is Example 11-1 and the latter is Example 11-2). Table 16 also shows, as a comparative example, the results when the conventional method (index R was set to 1.4) was used.

Table 16- Thickness: 40 μm Thickness: 60 μm Thickness: 80 μm Example 11-1 ○ ○ ○ Comparative Example 11-2 ○ ○ ○ Comparative Example 11 ×× × × [Evaluation] No collapse or the like occurred, but in Comparative Example 11, the occurrence of winding deviation was clearly observed, and the original winding also had a problem of being bent in an inverted C shape.

[Example 12] A film having a variation in thickness obtained immediately after the production line was started,
With respect to a film having almost no variation in thickness obtained after the production line was put into operation, the surface quality was examined by changing the desired thickness. The results are as shown in Table 17 (the former is Comparative Example 12 and the latter is Example 12). Note that “variable in thickness” means that the difference between the maximum thickness and the average thickness of the smooth portion excluding the side edge portion on which embossing is performed is larger than 5 μm, and “variation in thickness” The difference between the maximum thickness and the average thickness of the smooth portion except for the side edge portion on which embossing is performed is also 5 ".
μm or less. In addition, as a method of evaluating the surface quality, a method usually performed for a color photographic material, that is, an undercoating evaluation method was adopted because it is easy to visually discriminate it.

Incidentally, the undercoating coating evaluation method is as follows.
Generally speaking, the procedure is as follows. That is, first, an undercoat layer is formed on a film by using an undercoat coating solution comprising 3 parts by weight of a vinyl acetate-maleic anhydride alternating copolymer, 810 parts by weight of acetone, and 150 parts by weight of isopropanol. On the other hand, tin oxide
Antimony oxide composite fine particles (average particle size 0.05 μm) 1
A back layer is formed on the film by using a back layer coating solution comprising 4 parts by weight, 6 parts by weight of cellulose diacetate, 800 parts by weight of acetone, and 200 parts by weight of cyclohexane. After sufficiently drying the undercoat layer and the back layer, 4 parts by weight of gelatin and 10 parts of water were placed on the undercoat layer.
0 parts by weight, 0.2 parts by weight of methyl violet (dye),
Then, a gelatin solution containing a dye consisting of 0.1 part by weight of saponin is applied and dried.

Next, the thus-processed film is subjected to sharksten (a white board illuminated by a white light source).
And the following surface quality evaluations of A to E are made based on unevenness of transmitted light observed on the film surface. A: There is no unevenness, and the surface is very smooth. B: Fine unevenness is barely observed.

C: Fine unevenness is relatively easily recognized. D: Fine unevenness is clearly visible. E: Extremely large unevenness is observed. -Table 17- Thickness: 40 μm Thickness: 60 μm Thickness: 80 μm Example 12 AAA Comparative Example 12 DCC [Evaluation] In Example 12, there was no unevenness and very good surface quality was obtained. In Example 12, unevenness was conspicuous, and favorable surface quality was not obtained.

Although not particularly mentioned when each embodiment of the present invention has been described above, as a film manufacturing apparatus, a film interposing a tenter between drying boxes or a casting band surface from above and below is used. There is a device provided with a heater, a drying blower or the like so as to sandwich it, and a device using a drum instead of a casting band as a support (that is, a device configured to directly cast a dope onto a drum). Incidentally, the evaluation of the sample (film) was almost the same in any case of using any of these manufacturing apparatuses.

[0121]

According to the present invention, a high-quality film having a thickness of less than 85 μm can be stably and efficiently obtained.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram of a film manufacturing apparatus used when performing a film manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing the appearance of a transport roll according to a third embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a film manufacturing apparatus according to a fourth embodiment of the present invention.

FIG. 4 is a side view showing a main part of a film manufacturing apparatus used when performing a film manufacturing method according to a sixth embodiment of the present invention.

FIG. 5 is a perspective view showing the structure of a tension control unit according to a seventh embodiment of the present invention.

FIG. 6 is an external view of a roll used in tension control means (another embodiment) according to a seventh embodiment of the present invention.

FIG. 7 is a sectional view of a main part of the roll shown in FIG. 6;

FIG. 8 is a perspective view showing the structure of a tension control means (still another form) according to a seventh embodiment of the present invention.

FIG. 9 is a schematic structural diagram of a film manufacturing apparatus used when performing a film manufacturing method according to an eighth embodiment of the present invention.

FIG. 10 is an external view of a main part of a film manufacturing apparatus according to a ninth embodiment of the present invention.

FIG. 11 is a sectional view of a film according to an embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a general structure of a polarizing plate.

FIG. 13 is a schematic structural diagram of a conventional film manufacturing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 dope casting means 2 casting band (support) 3 peeling roll (peeling means) 4, 5 drying box (drying means) 6 winding core 7 winding means 8 tank 9 liquid sending pump 10 casting die 11a, 11b Drum 12 Transport roll M Decompression box (decompression means) W Web F Film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/30 G02B 5/30 // G02F 1/1335 510 G02F 1/1335 510 B29K 1:00 B29K 1: 00 B29L 7:00 B29L 7:00 C08L 101: 00 C08L 101: 00

Claims (22)

[Claims] 1. A thickness of 85 μm using a solution casting method.
A dope casting step of casting a dope, which is a raw material solution of the film, on a support, and a web formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, A winding step of winding a film obtained by drying the web, wherein the elastic modulus of the web is 0.1 kgf in the drying step.
/ Mm ² or more, wherein the web is dried so as to be maintained at not less than / mm ² . 2. The method according to claim 1, wherein the web is formed between the dope casting step and the peeling step, or between the peeling step and the drying step, or between the drying step and the winding step. The method for producing a film according to claim 1, wherein a pressure reduction treatment is performed. 3. A thickness of 85 μm using a solution casting method.
A dope casting step of casting a dope, which is a raw material solution of the film, on a support, and a web formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, A winding step of winding a film obtained by drying the web, wherein a tension Tk acting on the web in a transport direction thereof.
gf / mm ^2, and the elastic modulus Ykgf / mm ^{2 of the} web.
Conveys the web in a state that satisfies the following formula: T ≦ 20Y (when 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (when 0.1 ≦ Y) A method for producing a film, comprising: 4. A thickness of 85 μm using a solution casting method.
A dope casting device for casting a dope, which is a raw material solution of the film, on a support, wherein the dope is formed on the support by the dope casting device. A separating unit for separating the web from the support, and a drying unit for drying the web separated from the support by the separating unit while transporting the web through a plurality of transport rolls. And a winding means for winding a film obtained by drying the web by the drying means, wherein the web has a width of at least a part of transport rolls provided in the drying means. A film manufacturing apparatus characterized in that it is configured to be pulled in a direction. 5. A tension Tkgf / mm ² acting on the web along the web transport direction and an elastic modulus Y of the web.
kgf / mm ² satisfies the following equation: T ≦ 20Y (when 0 ≦ Y ≦ 0.1) or T ≦ 0.01Y + 1.999 (when 0.1 ≦ Y) The film manufacturing apparatus according to claim 4, wherein the apparatus is configured to convey a web. 6. A thickness of 85 μm using a solution casting method.
A dope casting device for casting a dope, which is a raw material solution of the film, on a support, wherein the dope is formed on the support by the dope casting device. A separating unit for separating the web from the support, and a drying unit for drying the web separated from the support by the separating unit while transporting the web through a plurality of transport rolls. A winding means for winding a film obtained by drying the web by the drying means; and acting on the web along a transport direction of the web provided in the middle of a transport path of the web. Transport tension control means for controlling tension, caused by rotational frictional resistance of a transport roll existing between the transport tension control means and the winding means. The sum of the mechanical losses, per conveyance path length 200m of the web, film manufacturing apparatus characterized by comprising been configured to be less 5kgf per web width 1 m. 7. A thickness of 85 μm using a solution casting method.
A dope casting step of casting a dope, which is a raw material solution of the film, on a support, and a web formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, A winding step of winding a film obtained by drying the web, wherein a contact pressure of the web in the drying step with respect to the transport rolls excluding a driving roll that generates a driving force is set to 0. A method for producing a film, wherein the pressure is 0001 to 0.5 kgf / cm ² . 8. A thickness of 85 μm using a solution casting method.
A dope casting step of casting a dope, which is a raw material solution of the film, on a support, and a web formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, And a winding step of winding a film obtained by drying the web. In the drying step, at least 80% of all the locations where the transport rolls are present, (weight of residual solvent in web) / Absolute dry weight of web) ×
The following relationship is established between the web residual solution W _s represented by 100 and the holding angle θ between two perpendiculars lowered from the portion of the web tangent to the transport roll to the rotation center of the transport roll. When W _s > 30, 5 ° <θ ≦ 180 °. When 0 ≦ W _s ≦ 30, the film is transported so as to satisfy 5 ° ≦ θ ≦ 270 °. 9. A thickness of 85 μm using a solution casting method.
A dope casting device for casting a dope, which is a raw material solution of the film, on a support, wherein the dope is formed on the support by the dope casting device. A separating unit for separating the web from the support, and a drying unit for drying the web separated from the support by the separating unit while transporting the web through a plurality of transport rolls. A winding unit for winding a film obtained by drying the web by the drying unit, wherein a winding unit is provided between the peeling unit and the drying unit and / or the drying unit and the winding unit. Tension control means for controlling the tension acting on the web is interposed along the transport direction of the web, and before and after the tension control means. The difference between the tension acting on that the web,
A film manufacturing apparatus characterized in that the film width is 1 kgf or more per 1 m of web width. 10. The apparatus according to claim 1, wherein the tension control means includes a drive roll also serving as a transport roll, and one or more drive rolls are provided for every 500 m of a web transport path length. 10. The film manufacturing apparatus according to 9. 11. A thickness of 85 μm using a solution casting method.
A method for producing a film having a thickness of less than m, comprising: a dope casting step of casting a dope as a raw material solution of the film on a support; and a dope casting step formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, and a drying step of drying the web. A winding step of winding a film obtained by drying the web, between the peeling step and the drying step, or between the drying step and the winding step, or A tension control process is performed between the peeling process and the winding process or in the middle of the drying process, and the difference in tension before and after the tension control process is the web width 1. So as to be hit 1kgf above, wherein in the tension control processing, along said conveying direction of the web, the film manufacturing method characterized by controlling the tension applied to the web. 12. The thickness of 85 μm using a solution casting method.
A method for producing a film having a thickness of less than m, comprising: a dope casting step of casting a dope as a raw material solution of the film on a support; and a dope casting step formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, A winding step of winding a film obtained by drying the web, wherein the drying step is to dry the web by passing through a drying area controlled at a predetermined drying temperature, A method for producing a film, wherein a temperature difference inside the drying area is set to be 10% or less of a temperature of a low-temperature (or high-temperature) drying area. 13. An inlet portion for entering the web into the drying zone and / or an outlet portion for discharging the web from the drying zone, wherein the web has a temperature within the temperature range of the drying zone. 13. The film production method according to claim 12, wherein the air having the following is supplied in a curtain shape. 14. A thickness of 85 μm using a solution casting method.
An apparatus for producing a film having a thickness of less than m, comprising: a dope casting means for casting a dope as a raw material solution of the film on a support; and a dope casting means formed on the support by the dope casting means. Peeling means for peeling the separated web from the support; and drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls. And a winding means provided with a winding core for winding a film obtained by drying the web by the drying means, wherein the winding surface of the winding core provided by the winding means has A step is formed along the rotation axis direction of the winding core,
Further, the height dimension of the step surface in the step portion is equal to the thickness of the film. 15. A thickness of 85 μm using a solution casting method.
An apparatus for producing a film having a thickness of less than m, comprising: a dope casting means for casting a dope as a raw material solution of the film on a support; and a dope casting means formed on the support by the dope casting means. Peeling means for peeling the separated web from the support; and drying means for drying the web peeled from the support by the peeling means while transporting the web through a plurality of transport rolls. And a winding means provided with a winding core for winding a film obtained by drying the web by the drying means, wherein the winding means comprises a winding core provided in the winding means. Is completed, the core deflection rate represented by [(the amount of central portion deflection in the core longitudinal direction / core diameter) × 100] is 5% or less. Film production equipment. 16. A thickness of 85 μm using a solution casting method.
A method for producing a film having a thickness of less than m, comprising: a dope casting step of casting a dope as a raw material solution of the film on a support; and a dope casting step formed on the support by the dope casting step. A peeling step of peeling the web from the support, a drying step of drying the web peeled from the support in the peeling step while transporting the web through a plurality of transport rolls, And a winding step of winding a film obtained by drying the web using a winding core. In the winding step, [thickness of wound film layer / (number of winding times × film thickness)] A film manufacturing method, wherein the film is wound around the winding core such that an index R represented by: 1.0 ≦ R ≦ 1.3. 17. The film according to claim 1, wherein the film comprises a lower fatty acid ester.
Claim 3, Claim 7, Claim 8, Claim 11, Claim 1
2. The method for producing a film according to any one of claims 13 and 16. 18. The film according to claim 4, wherein the film comprises a lower fatty acid ester.
The film manufacturing apparatus according to any one of claims 6, 9, 9, 10, 14, and 15. 19. The film according to claim 1, wherein the film is a protective film for a polarizing plate.
3. The method for producing a film according to claim 16. 20. The film according to claim 4, wherein the film is a protective film for a polarizing plate. The film manufacturing apparatus according to the above. 21. The method of claim 1, 2, 3,
The thickness obtained by using the film manufacturing method according to any one of claims 7, 8, 11, 11, 12, 13, 16, 17, and 19, 8
A film having a thickness of less than 5 μm, wherein a difference between a maximum thickness of a smooth portion excluding a side edge portion to be embossed and an average thickness is 5 μm or less. 22. The method of claim 4, claim 5, claim 6,
A film having a thickness of less than 85 μm, obtained by using the film manufacturing apparatus according to any one of claims 9, 10, 14, 15, 18, and 20. A film, wherein a difference between a maximum thickness of a smooth portion excluding a side edge portion to be embossed and an average thickness is 5 μm or less.