JP6955304B2 - Optical film manufacturing method - Google Patents

Description

The present disclosure relates to a method for producing an optical film.

In recent years, the demand for optical films has been increasing. Typical optical films include retardation films, antireflection films, antiglare films and the like.

The optical film is manufactured by a roll-to-roll continuous process using a long film-like support (hereinafter, "continuous film support") in order to improve productivity.
As an example of a method for producing an optical film, a coating film forming step of applying a coating liquid having a composition cured by active energy rays to the surface of a continuous film support and drying the coating film to form a coating film, and the formed coating film. Examples thereof include a method having a curing step of irradiating a film with active energy rays to cure the film, and forming a target optical functional layer on the surface of a continuous film support.

As a method for curing a coating film applied to a method for producing an optical film, for example, there is a method described in Patent Document 1.
In Patent Document 1, a coating film made of an active ray-curable resin formed on the surface of a traveling strip-shaped flexible support is irradiated with active rays by a plurality of active ray irradiating means to cure the coating film. In the method of curing a film, a coating film is kept in a deoxidized atmosphere until a flexible support irradiated with active rays by one or more active ray irradiation means is run on a next-stage active ray irradiation means. A method for curing a film is disclosed. Then, in Patent Document 1, a closed space is formed between a plurality of active ray irradiating means, the inert gas is supplied into the closed space, and the coating film is irradiated with the active ray. It is disclosed that the flexible support having the above-mentioned is wound around a heated backup roll.

Further, Patent Document 2 is a method for producing an optical film including a long base film and a cured layer, which includes a base film and a pre-cured layer that can be cured by active energy rays. The base film of the film is heated in a state where the effective part of the base film is in the air, and the heated base film is brought into contact with a back roll at 30 ° C. or higher to form a pre-curing layer. A method for producing an optical film is disclosed, which includes a step of curing a pre-curing layer to obtain a cured layer by irradiating an active energy ray. Further, Patent Document 2 also discloses that the pre-curing layer is irradiated with active energy rays in an inert gas atmosphere.

Further, in Patent Document 3, after providing the active energy ray-curable resin layer on the resin film, the active energy ray-curable resin layer is cured by irradiating the active energy ray-curable resin layer with active energy rays from a light source while transporting the resin film. This is a method for manufacturing a hard coat film, in which an inert gas is irradiated with an active energy ray by using a gas supply pipe installed so that the axial direction is parallel to the width direction of the resin film. A method for producing a hard coat film to be supplied to the surface of a curable resin layer is disclosed. Further, Patent Document 3 also discloses that while supporting and transporting a resin film on the back surface of the resin film with a backup roll, irradiation of active energy rays and supply of an inert gas are performed.

In addition, Patent Document 4 describes in the energy ray irradiation region in an energy ray irradiating device for irradiating an adhesive sheet having an energy ray-curable adhesive layer attached to an adherend surface of an adherend with energy rays. An energy ray irradiation device including a heating means for heating the inert gas before supplying the inert gas is disclosed.

Japanese Unexamined Patent Publication No. 2006-247530 Japanese Unexamined Patent Publication No. 2017-111394 JP-A-2009-240921 Japanese Unexamined Patent Publication No. 2013-141651

In the production of the optical film, in the above-mentioned curing step, in order to suppress the inhibition of the curing reaction by oxygen, for example, the continuous film support on which the coating film is formed is conveyed and passed through the reaction chamber filled with the inert gas. It is done during the process.
Further, the coating film is cured by irradiation with active energy rays in order to accelerate the curing reaction by wrapping a support on which the coating film is formed around a heated backup roll in the above reaction chamber. There is.
However, when the continuous film support on which the coating film is formed comes into contact with the backup roll heated in the reaction chamber, a temperature difference is formed between the side on which the coating film is formed and the side in contact with the backup roll, and this temperature. Wrinkles may occur due to the difference.
If the generated wrinkles are large or large, the optical performance of the optical film becomes non-uniform, and the quality of the product deteriorates.
Here, the wrinkles caused by the above temperature difference refer to wrinkles having a wavy shape, which are generated by arranging several to several hundreds of wrinkles in a size of several mm in the width direction on the continuous film support. This wrinkle tends to occur constantly regardless of the joint portion in the continuous film support (that is, the joint portion in which the films are joined to make the film longer). If the wrinkles are large (strong), the wrinkles may be continuous in the longitudinal direction.

In the method for curing a coating film described in Patent Document 1, when the coating film of a flexible support having a coating film is irradiated with active rays, the side on which the coating film is formed and the side in contact with a heated backup roll There is a temperature difference between and, and wrinkles occur.
Also in the case of the method for producing an optical film described in Patent Document 2, when the pre-curing layer of the base film having the pre-curing layer is irradiated with active energy rays, the side on which the pre-curing layer is formed and the heated back are used. There is a temperature difference between the side that comes into contact with the roll, and wrinkles occur.
In the method for producing a hard coat film described in Patent Document 3, heating of a backup roll is not mentioned.
The energy ray irradiating apparatus described in Patent Document 4 does not mention that the energy ray irradiation is performed by wrapping a resin film having an energy ray-curable adhesive layer around a backup roll.

Therefore, the problem to be solved by one embodiment of the present invention has been made in view of the above circumstances, and the occurrence of wrinkles is reduced in the method for producing an optical film including a step of curing a coating film with active energy rays. It is an object of the present invention to provide a method for producing an optical film.

Means for solving the above problems include the following embodiments.
<1> A coating film forming step of forming a coating film cured by active energy rays on a continuous film support, and
In the reaction chamber where the inert gas is supplied and filled and the internal atmosphere is heated by the heating means, the coating film is formed in the region where the continuous film support on which the coating film is formed is wound around the heated backup roll. The curing process of irradiating the film with active energy rays to cure the coating film,
A method for producing an optical film having.

<2> The method for producing an optical film according to <1>, wherein the heating means for heating the internal atmosphere in the reaction chamber is the heating means for heating the inert gas.
<3> The method for producing an optical film according to <1> or <2>, wherein the heating means heats the inert gas supplied to the reaction chamber to heat the internal atmosphere in the reaction chamber.

<4> A coating film forming step of forming a coating film cured by active energy rays on a continuous film support, and
In the reaction chamber to which the inert gas is supplied and filled, the surface of the continuous film support on which the coating film is formed is heated, and the continuous film support on which the coating film is formed is wound on a heated backup roll. A curing step of irradiating the coating film with active energy rays in the applied area to cure the coating film,
A method for producing an optical film having.

<5> The method for producing an optical film according to <4>, wherein the surface on which the coating film of the continuous film support is formed is heated by the heated inert gas.
<6> A heated inert gas is applied to the surface of the continuous film support on which the coating film is formed to heat the surface of the continuous film support on which the coating film is formed. <4> or <5> The method for producing an optical film according to.

<7> In the reaction chamber, a heated inert gas is applied to the surface of the continuous film support on which the coating film is formed up to the separation point between the continuous film support and the backup roll, and the continuous film support is subjected to. The method for producing an optical film according to <6>, wherein the surface on which the coating film is formed is heated.
<8> In the reaction chamber, a heated inert gas is applied to the surface of the continuous film support on which the coating film is formed up to the contact point between the continuous film support and the backup roll, and the continuous film support is subjected to. The method for producing an optical film according to <6> or <7>, wherein the surface on which the coating film is formed is heated.

<9> The method for producing an optical film according to any one of <1> to <8>, wherein the total thickness of the continuous film support on which the coating film is formed is 3 μm or more and 115 μm or less.
<10> The method for producing an optical film according to any one of <1> to <9>, wherein the surface temperature of the backup roll in the reaction chamber is 80 ° C. or higher and 250 ° C. or lower.

<11> in the reaction chamber, when the temperature at the contact point between the continuous film support and the backup roll and T ₁ ° C., the surface temperature of the backup roll which is heated to a T ₂ ° C., T ₁ is T ₂ -20 The method for producing an optical film according to any one of <1> to <10>, wherein the temperature is not less than or equal to _{T 2 and not} more than 20 ° C.

<12> The temperature at the contact point between the continuous film support and the backup roll in the reaction chamber is T ₁ ° C, the surface temperature of the heated backup roll is T ₂ ° C, and the continuous film support on which the coating film is formed. The method for producing an optical film according to any one of <1> to <10>, which satisfies the following formula (1) when the total thickness of the body is tμm.
Equation (1) 0 ≤ | T _2- T ₁ | ≤ t

<13> The optical film according to any one of <1> to <12>, further comprising a preheating step of heating the continuous film support on which the coating film is formed after the coating film forming step and before the curing step. Manufacturing method.

According to one embodiment of the present invention, there is provided a method for producing an optical film in which the occurrence of wrinkles is reduced in the method for producing an optical film including a step of curing a coating film with active energy rays.

It is the schematic which shows each process of the manufacturing method of the optical film of 1st Embodiment. It is the schematic which shows each process of the manufacturing method of the optical film of 2nd Embodiment. It is the schematic for demonstrating the discharge direction of the inert gas in Example 26.

Hereinafter, embodiments of a method for manufacturing an optical film will be described. However, the present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within the scope of the object of the present invention.

The numerical range indicated by using "~" in the present disclosure means a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
Each element in each of the drawings presented in this disclosure is not necessarily on an exact scale, with an emphasis on clearly showing the principles of this disclosure and some emphasis.
Further, in each drawing, components having the same function are designated by the same reference numerals, and duplicate description will be omitted.
In the present disclosure, "warming" means raising the temperature of an object to a desired temperature.

≪Manufacturing method of optical film≫
The present inventors have studied a method for producing an optical film including a step of curing a coating film with active energy rays in a continuous process of a roll-to-roll method, and as a result, the occurrence of wrinkles is reduced by the following method. I found out what I could do.
That is, the coating film of the continuous film support on which the coating film is formed is irradiated with active energy rays, and the support having the coating film formed on the back-up roll heated in the reaction chamber filled with the inert gas is applied. In the curing step of winding, the atmospheric temperature in the reaction chamber is heated by a heating means, or the surface on which the coating film of the continuous film support is formed is heated in the reaction chamber.
By adopting the above method, when the continuous film support on which the coating film is formed comes into contact with the backup roll heated in the reaction chamber, the side where the coating film is formed and the side which comes into contact with the backup roll The temperature difference between them can be reduced indirectly or directly. As a result, it is possible to reduce the occurrence of wrinkles due to the temperature difference formed between the side on which the coating film is formed and the side in contact with the backup roll.

[First Embodiment and Second Embodiment]
From the above, the method for producing an optical film of the first embodiment is a coating film forming step of forming a coating film cured by active energy rays on a continuous film support (hereinafter, "coating film forming step (1)". ) ”), And the continuous film support on which the coating film is formed is wrapped around the heated backup roll in the reaction chamber where the inert gas is supplied and filled and the internal atmosphere is heated by the heating means. This is a method for producing an optical film, which comprises a curing step (hereinafter, also referred to as “curing step (1)”) of irradiating the coating film with active energy rays to cure the coating film in the region.

Further, the method for producing an optical film of the second embodiment is also referred to as a coating film forming step (hereinafter, "coating film forming step (2)") for forming a coating film cured by active energy rays on a continuous film support. In the reaction chamber to which the inert gas was supplied and filled, the surface of the continuous film support on which the coating film was formed was heated, and the continuous film support on which the coating film was formed was heated. A method for producing an optical film, which comprises a curing step (hereinafter, also referred to as "curing step (2)") of irradiating the coating film with active energy rays in a region wound around a backup roll to cure the coating film. Is.

According to the method for producing an optical film of the first embodiment and the second embodiment, a cured film is formed on the continuous film support through the curing step (1) or the curing step (2). ..
The cured film formed becomes an optical functional layer (for example, an optically anisotropic layer, an antireflection layer, an antiglare layer, a lenticular lens layer, etc.) in the optical film.
).

Hereinafter, details of the coating film forming step (1) and the curing step (1) in the method for producing an optical film of the first embodiment will be described first.

[Coating film forming step (1)]
In the coating film forming step (1), a coating film cured by active energy rays is formed on the continuous film support.
The coating film forming step (1) is preferably carried out by using a coating liquid having a composition that is cured by active energy rays, applying this coating liquid on a continuous film support, and drying the coating liquid.

An example of the coating film forming step (1) will be described with reference to FIG.
As shown in FIG. 1, when the tip of the wound continuous film support F is sent out, the coating means 1 first applies a coating liquid having a composition that is cured by active energy rays, and then the film is dried. It is dried in the drying area by means 2. In this way, a coating film obtained by applying and drying a coating liquid having a composition that is cured by active energy rays is formed on the continuous film support.

-Continuous film support-
A known polymer film can be used as the continuous film support used in the production of the optical film.
Examples of polymer film materials used as continuous film supports include cellulose acylate (eg, cellulose triacetate (triacetyl cellulose, refractive index 1.48), cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate. ), Polyethylene such as polyethylene and polypropylene, Polyester terephthalate, Polyester such as polyethylene naphthalate, Acrylic resin such as polyethersulfone and polymethylmethacrylate, Polysulfone, Polysulfone, Polysulfone, Polyether, Polymethylpentene, Polyetherketone, Poly ( Meta) Acrylic nitrile, polymer having an alicyclic structure (for example, norbornene resin (trade name "Arton (registered trademark)", JSR), amorphous polyolefin (for example, trade name "Zeonex (registered trademark)"), Japan Zeon Co., Ltd.)), etc.
Of these, triacetyl cellulose, polyethylene terephthalate (PET), and a polymer having an alicyclic structure are preferable, and triacetyl cellulose is particularly preferable, from the viewpoint of low optical anisotropy.

The thickness of the continuous film support may be determined according to manufacturing suitability, application, user's request, etc., and for example, a film in the range of 3 μm to 250 μm is used. In particular, when the thickness of the continuous film support is thin, wrinkles tend to occur. However, by adopting the curing step (1) described later, a thin continuous film support in the range of 3 μm to 100 μm can be obtained. It is preferably used.
From the viewpoint of high applicability to winding on a backup roll, 15 μm or more is more preferable, and from the viewpoint of material cost, 80 μm or less is preferable.

-Applying-
Known coating means are applied for coating.
Specific examples of the coating means include curtain coating method, dip coating method, spin coating method, printing coating method, spray coating method, slot coating method, roll coating method, slide coating method, blade coating method, gravure coating method, and wire. The bar method and the like can be mentioned.

− Drying −
Known drying means are applied to the drying.
Specific examples of the drying means include a method using an oven, a warm air blower, an infrared (IR) heater, and the like.
In drying with a warm air blower, warm air may be applied from the surface of the continuous film support opposite to the surface on which the coating liquid is applied, and the surface of the applied coating liquid is diffused so as not to flow with the warm air. A board may be installed.
The drying conditions may be determined according to the type of coating liquid used, the coating amount, the transport speed, and the like. For example, the drying conditions are preferably carried out in the range of 30 ° C. to 140 ° C. for 10 seconds to 10 minutes.

Through the above coating film forming step (1), an uncured coating film that is cured by active energy rays is formed.
The total thickness of the continuous film support on which the coating film is formed, which is obtained through the coating film forming step (1), is preferably 3 μm or more and 115 μm or less, and more preferably 3 μm or more and 80 μm or less.
The smaller the total thickness of the continuous film support on which the coating film is formed, the more likely it is that wrinkles will occur in the curing process. Therefore, the thinner the total thickness as described above, the easier it is to obtain the effect of suppressing the occurrence of wrinkles by the curing step (1) described later.
Here, the total thickness of the continuous film support on which the coating film is formed is the thickness of the continuous film support itself when a plurality of coating films are laminated on the continuous film support. The total thickness of the layers.

[Curing step (1)]
In the curing step (1), the continuous film support on which the coating film is formed is wound around a heated backup roll in the reaction chamber in which the inert gas is supplied and filled and the internal atmosphere is heated by the heating means. The coating film is cured by irradiating the coating film with active energy rays in the region.
Here, the heating means in the curing step (1) is a means for heating the internal atmosphere of the reaction chamber as described above, and is a means provided for suppressing the occurrence of wrinkles.

An example of the curing step (1) will be described with reference to FIG.
As shown in FIG. 1, the continuous film support F on which the coating film is formed is irradiated with active energy rays in the reaction chamber 3.
Specifically, the continuous film support F on which the coating film is formed is wound around the backup roll 34 in the reaction chamber 3, and in this region, the active energy ray is applied to the coating film by the exposure light source 32. Is irradiated.
A heated inert gas is supplied from the nozzle 36a into the reaction chamber 3, and the inert gas is filled in the reaction chamber 3. The heated inert gas heats the internal atmosphere of the reaction chamber 3.

FIG. 1 shows an embodiment in which the internal atmosphere of the reaction chamber 3 is heated by supplying the heated inert gas from the nozzle 36a and filling the reaction chamber 3 with the heated inert gas. The step (1) is not limited to this.
In the curing step (1), the internal atmosphere may be heated by the heating means, and examples thereof include a mode in which the inert gas is heated by the heating means and a mode in which the inner wall of the reaction chamber is heated by the heating means.
The internal atmosphere of the reaction chamber can be adjusted by appropriately adjusting the heating conditions by the heating means, the temperature of the inert gas, the supply amount of the inert gas, the discharge amount of the inert gas, the transport speed of the continuous film support, and the like. The temperature of the can be controlled.

When the embodiment in which the inert gas is heated by the heating means is adopted in the curing step (1), the means for the heating means to preheat the inert gas supplied from the nozzle 36a into the reaction chamber 3 as described above. The heating means may be a means for heating the inert gas supplied to the reaction chamber in the reaction chamber. In the latter case, the heating means is, for example, a heating plate installed in the reaction chamber, and a method of applying an inert gas to the heating plate to heat the inert gas in the reaction chamber can be mentioned.

-Active energy ray-
The active energy ray used in the curing step (1) is not particularly limited as long as it can impart energy capable of generating active species to the coated film to be irradiated. Specific examples of the active energy ray include α-rays, γ-rays, X-rays, ultraviolet rays, infrared rays, visible rays, and electron beams. Of these, ultraviolet rays or electron beams are preferable, and ultraviolet rays are more preferable, as the active energy rays used in the curing step (1) from the viewpoint of curing sensitivity and availability of an apparatus.

-Inert gas-
Examples of the inert gas used in the curing step (1) include nitrogen gas, argon gas, neon gas, carbon dioxide gas and the like, and among them, nitrogen gas is preferable.

-Exposure light source-
Examples of the exposure light source used for irradiating the active energy ray in the curing step (1) include the above-mentioned light source of the active energy ray. From the viewpoint of curing sensitivity and availability of the apparatus, an ultraviolet light source is preferable as the exposure light source.
Examples of the light source of ultraviolet rays include tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps, mercury xenon lamps, carbon arc lamps and other lamps, and various lasers (eg, semiconductor lasers, helium neon lasers, argon ions). Examples include lasers, helium cadmium lasers, YAG (Yttrium Aluminum Garnet) lasers), light emitting diodes, and cathode wire tubes.
The peak wavelength of ultraviolet rays emitted from the light source of ultraviolet rays is preferably 200 nm to 400 nm.

-Backup roll-
The backup roll used in the curing step (1) is not particularly limited, and known ones can be used.
As the backup roll, for example, one having a hard chrome-plated surface can be preferably used.
The thickness of the plating is preferably 40 μm to 60 μm from the viewpoint of ensuring conductivity and strength.
The surface roughness of the backup roll is preferably 0.1 μm or less in terms of surface roughness Ra from the viewpoint of reducing the variation in the frictional force between the continuous film support and the backup roll.

The backup roll in the curing step (1) is heated in order to increase the curing rate and curing efficiency of the coating film.
The surface temperature of the backup roll may be determined according to the composition of the coating film, the curing performance of the coating film, the heat resistance of the continuous film support, etc., and is preferably 60 ° C. to 250 ° C., more preferably 80 ° C. to 250 ° C. It is preferable, and more preferably 80 ° C. to 150 ° C.
By setting the surface temperature of the backup roll to the above temperature, the curing speed of the coating film can be increased, and the temperature of the continuous film support to be wound can be controlled.
The surface temperature of the backup roll is measured as follows.
That is, the surface temperature of the surface of the backup roll is measured with a radiation thermometer (for example, FT-H30 manufactured by KEYENCE) at any five points in the width direction of the backup roll. The average value of the measured values is taken as the surface temperature of the backup roll.

It is preferable that the backup roll detects the surface temperature and the surface temperature of the backup roll is maintained by the temperature control means based on the temperature.
The temperature control means of the backup roll includes a heating means and a cooling means. Induction heating, water heating, oil heating and the like are used as the heating means, and cooling with cooling water is used as the cooling means.

The diameter of the backup roll is preferably 100 mm to 1000 mm, more preferably 100 mm to 800 mm, from the viewpoints of easy winding of the continuous film support, easy irradiation of active energy rays, and manufacturing cost of the backup roll. , 200 mm to 700 mm is more preferable.

In the curing step (1), since the continuous film support in a stretched state is irradiated with active energy rays, tension is applied in the longitudinal direction to the continuous film support around which the backup roll is wound. It is preferable to have.
The tension applied in the longitudinal direction of the continuous film support on the backup roll is preferably 100 N / m to 600 N / m.

The transport speed of the continuous film support on the backup roll is preferably 10 m / min or more and 100 m / min or less from the viewpoint of ensuring productivity and improving the accuracy of irradiation with active energy rays. It is more preferably 20 m / min or more and 60 m / min or less.

The lap angle of the continuous film support with respect to the backup roll is preferably 60 ° or more, more preferably 90 ° or more.
The lap angle is defined as the transport direction of the continuous film support when the continuous film support comes into contact with the backup roll and the transport direction of the continuous film support when the continuous film support is separated from the backup roll. The angle that becomes.

-Nozzle-
The nozzle for supplying the inert gas into the reaction chamber may be installed at any position in the reaction chamber, and the discharge direction of the inert gas is not limited.
As described above, if the internal atmosphere of the reaction chamber is heated by heating the inert gas supplied to the reaction chamber, the occurrence of wrinkles can be efficiently reduced. It is preferable that the method is the same as in the preferred embodiment of the nozzle installation position and the ejection direction of the inert gas discharged from the nozzle in the method for producing the optical film of the second aspect.
Here, in order to heat the inert gas supplied into the reaction chamber 3, the piping of the inert gas leading to the nozzle may be heated by a heating means (for example, a coil heater or the like).

-Internal atmosphere temperature-
If the temperature of the internal atmosphere of the reaction chamber is warmer than the outside air temperature of the reaction chamber, the effect of reducing the occurrence of wrinkles can be obtained, but the closer it is to the surface temperature of the backup roll, the less the occurrence of wrinkles. The effect is high.

Specifically, the reaction chamber, the temperature at the contact point between the continuous film support and the backup roll and T ₁ ° C., if the surface temperature of the backup roll was T ₂ ° C., T ₁ is T ₂ -20 ° C. or higher It is preferably T ₂ + 20 ° C. or lower. That is, the temperature T ₁ is preferably within ± 20 ° C. with respect to the temperature T _2. In particular, in the curing step (1), it is most preferable that _{the temperature T 1} = the temperature T _{2.
Here, the "temperature T 1} at the contact point between the continuous film support and the backup roll" in the present disclosure refers to the coating film surface at the contact point between the continuous film support and the backup roll (point P in FIG. 1). Refers to the temperature measured at a position separated by 1 mm.
The temperature T ₁ is set at a position 1 mm away from the coating film surface at the contact point between the continuous film support and the backup roll (point P in FIG. 1) in the reaction chamber, and a thermometer (for example, a thermoelectric pair) is installed. Just install and measure.

It is also preferable that the temperature of the internal atmosphere of the reaction chamber satisfies the following formula (1).
That is, the temperature at the contact point between the continuous film support and the backup roll in the reaction chamber is T ₁ ° C, the surface temperature of the heated backup roll is T ₂ ° C, and the continuous film support on which the coating film is formed is formed. When the total thickness of is tμm, it is preferable to satisfy the following formula (1).
Equation (1) 0 ≤ | T _2- T ₁ | ≤ t
According to the formula (1), the smaller the total thickness of the continuous film support on which the coating film is formed, the smaller the difference between _{the temperature T 2} and the temperature T _{1 is preferably.} Further, when the total thickness of the continuous film support on which the coating film is formed is large, it means that the permissible range of the difference between the _{temperature T 2} and the temperature T _{1 becomes large.} This is because the smaller the total thickness of the continuous film support on which the coating film is formed, the more likely it is that wrinkles will occur.
Further, it is more preferable that the temperature of the internal atmosphere of the reaction chamber 3 satisfies the following formula (2).
Equation (2) 0 ≤ | T _2- T ₁ | ≤ t / 2
Here, the total thickness of the continuous film support on which the coating film is formed is preferably 3 μm or more and 115 μm or less (more preferably 3 μm or more and 80 μm or less).
Further, the surface temperature of the heated backup roll is T ₂ , and it is preferably 80 ° C. or higher and 250 ° C. or lower (more preferably 80 ° C. or higher and 150 ° C. or lower).

Through the above curing step (1), the coating film is cured, and a cured film (that is, an optical functional layer) is formed on the continuous film support.

Subsequently, the details of the coating film forming step (2) and the curing step (2) in the method for manufacturing the optical film of the second embodiment will be described.

[Coating film forming step (2)]
In the coating film forming step (2), a coating film cured by active energy rays is formed on the continuous film support.

An example of the coating film forming step (2) will be described with reference to FIG.
As shown in FIG. 2, when the tip of the wound continuous film support F is sent out, the coating means 1 first applies a coating liquid having a composition that is cured by active energy rays, and then the film is dried. It is dried in the drying area by means 2. In this way, a coating film obtained by applying and drying a coating liquid having a composition that is cured by active energy rays is formed on the continuous film support.

As shown in FIG. 2, the coating method, the drying method, and the like in the coating film forming step (2) are the same as those in the above-mentioned coating film forming step (1), and the preferred embodiments are also the same, so detailed description thereof will be omitted. do.

Through the above coating film forming step (2), an uncured coating film that is cured by active energy rays is formed.
The total thickness of the continuous film support on which the coating film is formed, which is obtained through the coating film forming step (2), is the total thickness of the continuous film support on which the coating film is formed, which is obtained through the coating film forming step (1). It is the same as the total thickness, and the preferable range is also the same.

[Curing step (2)]
In the curing step (2), in the reaction chamber to which the inert gas is supplied and filled, the surface of the continuous film support on which the coating film is formed is heated, and the continuous film support on which the coating film is formed is added. The coating film is cured by irradiating the coating film with active energy rays in a region wound around a warmed backup roll.

An example of the curing step (2) will be described with reference to FIG.
As shown in FIG. 2, the continuous film support F on which the coating film is formed is irradiated with active energy rays in the reaction chamber 3.
Specifically, the continuous film support F on which the coating film is formed is wound around the backup roll 34 in the reaction chamber 3, and in this region, the active energy ray is applied to the coating film by the exposure light source 32. Is irradiated.
A heated inert gas is supplied from the nozzle 36b into the reaction chamber 3, and the heated inert gas hits the surface of the continuous film support F on which the coating film is formed. Has been done. That is, by applying the heated inert gas, the surface of the continuous film support F on which the coating film is formed is heated.

FIG. 2 shows an embodiment in which the inert gas heated from the nozzle 36b is supplied into the reaction chamber 3 and the inert gas is applied to the surface of the continuous film support F on which the coating film is formed. 2) is not limited to this.
In the curing step (2), in addition to the above aspect, another aspect of heating the surface on which the coating film of the continuous film support is formed by the heated inert gas is the inert activity heated in the reaction chamber. An embodiment in which gas is supplied, the gas is applied to the surface of the continuous film support opposite to the surface on which the coating film is formed, and the surface of the continuous film support on which the coating film is formed is indirectly heated. .. In addition to this, a mode in which a heated roll, belt, etc. is applied to the surface on which the coating film of the continuous film support is formed or the opposite surface, and the coating film of the continuous film support is formed by utilizing radiant heat. A method of heating the surface can be mentioned.
The temperature of the inert gas, the shape and position of the outlet of the inert gas, the supply amount of the inert gas, the discharge amount of the inert gas, the surface temperature of the roll, belt, etc., the transport speed of the continuous film support, etc. By adjusting as appropriate, the temperature of the surface on which the coating film of the continuous film support is formed can be controlled.

In the case of the mode in which the surface on which the coating film of the continuous film support is formed is heated by the heated inert gas in the curing step (2), the following is preferable.
That is, in the reaction chamber, the surface on which the coating film of the continuous film support is formed up to the separation point between the continuous film support and the backup roll (corresponding to the point Q in FIG. 2) is heated and inert. A gas is applied to heat the surface of the continuous film support on which the coating film is formed.
For this method, the installation position of the nozzle in the reaction chamber and the position of the outlet of the inert gas may be adjusted.
That is, the heated inert gas is applied to the coating film of the continuous film support conveyed into the reaction chamber up to the separation point (point Q in FIG. 2) between the continuous film support and the backup roll. .. By applying the warmed inert gas at this timing, the coating film is applied on the continuous film support having a coating film, as compared with the case where the heated inert gas is applied after the continuous film support and the backup roll are separated from each other. The temperature difference between the side on which the gas is formed and the side in contact with the backup roll becomes difficult to form, and the occurrence of wrinkles can be effectively suppressed.

Further, in the reaction chamber, the inert gas heated on the surface on which the coating film of the continuous film support is formed up to the contact point between the continuous film support and the backup roll (corresponding to the point P in FIG. 2). It is more preferable to heat the surface of the continuous film support on which the coating film is formed.
For this method, the installation position of the nozzle in the reaction chamber and the position of the outlet of the inert gas may be adjusted.
That is, the heated inert gas is applied to the coating film of the continuous film support F that has been conveyed into the reaction chamber up to the contact point between the continuous film support and the backup roll. By applying the warmed inert gas at this timing, the surface of the continuous film support on which the coating film is formed comes into contact with the backup roll in a heated state, so that the coating film is formed. The temperature difference between the side and the side in contact with the backup roll becomes more difficult to form, and the occurrence of wrinkles can be suppressed more effectively.

In the embodiment in which the surface on which the coating film of the continuous film support F is formed is heated by the heated inert gas, the coating film of the continuous film support is formed from an outlet having a width longer than the width of the continuous film support. It is preferable to apply the warmed inert gas to the entire width direction of the surface on which the film is formed.
Further, it is preferable that the outlet is installed so that the discharge direction of nitrogen gas is substantially perpendicular to the coating film surface.
Further, the outlet is slit-shaped or has holes arranged in one or more rows from the point of uniformly applying the inert gas to the entire width direction of the surface on which the coating film of the continuous film support is formed. The shape is preferable.

The active energy rays, the inert gas, the exposure light source, the backup roll, the temperature of the internal atmosphere, etc. in the curing step (2) are the same as those in the curing step (1) described above, and the preferred embodiments are also the same. The description is omitted.

Through the above curing step (2), the coating film is cured, and an optical functional layer (that is, an optical functional layer) is formed on the continuous film support.

[Preheating process]
In the method for producing an optical film of the first embodiment and the second embodiment, there is a preheating step of heating the continuous film support on which the coating film is formed after the coating film forming step and before the curing step. Is preferable.
By having this step, the continuous film support F having the coating film is conveyed to the curing step in a heated state and comes into contact with the backup roll, so that the side on which the coating film is formed and the backup roll It becomes difficult to make a temperature difference with the side that comes into contact with the film, and the occurrence of wrinkles can be effectively suppressed.

-Heating method-
The method for heating the continuous film support on which the coating film is formed in the preheating step is not particularly limited, and a contact heating method or a non-contact heating method may be used.
Examples of the contact heating method include a method in which a continuous film support on which a coating film is formed is brought into contact with a heated roll, belt, or the like. The non-contact heating method includes a method of blowing warm air onto a continuous film support on which a coating film is formed, a method of heating a continuous film support on which a coating film is formed by radiant heat, and a heating zone such as an oven. Examples thereof include a method of passing a continuous film support on which a coating film is formed.
Specific examples of the preheating step include, as shown in FIGS. 1 and 2, a method in which the continuous film support F on which the coating film is formed is brought into contact with the heated roll 4. In order to improve the temperature control performance of the continuous film support F on which the coating film is formed, the continuous film support F on which the coating film is formed may be wound around the roll 4 and conveyed.

In the preheating step, the temperature of the coating surface or the opposite surface (that is, the back surface of the continuous film support) of the continuous film support on which the coating film is formed is close to the surface temperature of the backup roll in the curing step. It is preferable that it is heated so as to become.
That is, the temperature of the coating film surface or the opposite surface of the continuous film support on which the coating film is formed by heating in the preheating step is preferably 60 ° C. to 250 ° C., preferably 80 ° C. to 250 ° C. More preferably, it is more preferably 80 ° C. to 150 ° C.
Further, when the temperature of the coating film surface or the opposite surface of the continuous film support on which the coating film is formed is T ₃ ° C. and the surface temperature of the heated backup roll is T ₂ ° C., T ₃ is T. ₂ is preferably -20 ° C. or more _T 2 + 20 ° C. or less. That is, the temperature T ₃ is preferably within ± 20 ° C. with respect to the temperature T _2. Further, considering that the temperature drops during transportation to the reaction chamber after the continuous film support on which the coating film is formed is heated, it is preferable to satisfy the relationship of _{temperature T 3} > temperature T _2. ..

As described above, the optical functional layer which is a cured film is formed on the continuous film support.
Examples of the optical functional layer formed by the methods for producing the optical film of the first embodiment and the second embodiment include an optically anisotropic layer in a retardation film, an antireflection layer in an antireflection film, and an antiglare layer in an antiglare film. Examples include a glare layer and a lenticular lens layer of a lenticular sheet.
That is, according to the method for producing an optical film according to the first embodiment and the second embodiment, a retardation film having an optically anisotropic layer, an antireflection film having an antireflection layer, and an antiglare having an antiglare layer. A film, a lenticular sheet having a lenticular lens layer, or the like can be obtained.

[Manufacturing method of retardation film]
Hereinafter, a method for producing a retardation film will be described as an example of the method for producing an optical film according to the first embodiment and the second embodiment.
The retardation film is an optically anisotropic layer containing an oriented and immobilized liquid crystal compound and an alignment layer having an orientation regulating force for arranging the liquid crystal compounds of the liquid crystal layer in a certain direction on a continuous film support (hereinafter referred to as an optically anisotropic layer). , Also referred to as a liquid crystal layer), are provided in this order.

(Orientation layer and its formation method)
The alignment layer in the retardation film is not particularly limited as long as it has an orientation regulating force for arranging the liquid crystal compounds in the liquid crystal layer in a certain direction.
Examples of the alignment layer in the retardation film include an alignment layer to which an orientation regulating force is applied to a liquid crystal compound by a rubbing method, specifically, a layer of an organic compound (preferably a polymer) subjected to a rubbing treatment. can.
Here, the rubbing method is a method of restricting the orientation of a liquid crystal compound on a coating film by rubbing the surface of a coating film containing a material for forming an alignment layer (hereinafter, also referred to as a coating film for an alignment layer) with a rubbing cloth in a certain direction. It is a method of giving power. Further, a process of rubbing the surface of the coating film for an alignment layer with a rubbing cloth in a certain direction is called a rubbing process.

-Material for forming an orientation layer-
The material for forming the alignment layer used for forming the alignment layer preferably contains the following organic compound and a solvent for dissolving the organic compound. Examples of the organic compound include polymethylmethacrylate and acrylic acid / styrenic acid. Polymer, styrene / maleinimide copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyl toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, Examples thereof include polymers such as vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, polyethylene, polypropylene, and polycarbonate, and compounds such as silane coupling agents.
Examples of preferred polymers include polyimides, polystyrenes, polymers of styrene derivatives, polyvinyl alcohols, and alkyl-modified polyvinyl alcohols having an alkyl group (preferably an alkyl group having 6 or more carbon atoms).
As the polymer used as the material for forming the alignment layer, alkyl-modified polyvinyl alcohol is particularly preferable, and the alkyl group having 6 to 14 carbon atoms is -S-,-(CH ₃ ) C (CN)-, or-(. C ₂ H ₅ ) Alkyl-modified polymer alcohol bonded to the terminal or side chain of polyvinyl alcohol via N-CS-S- is preferable.

As the coating film for the alignment layer, the same methods as the coating method and the drying method in the coating film forming step (1) or (2) described above can be used, and the preferred embodiment is also the same.
The film thickness of the coating film for the alignment layer is preferably 0.1 μm to 5 μm, more preferably 0.2 μm to 1 μm.

-Giving orientation control force-
In the case of the rubbing method, the surface of the coating film for the alignment layer formed on the continuous film support may be rubbed with a rubbing cloth in a certain direction.
The rubbing treatment is not particularly limited, and a known method can be applied. Specifically, as the rubbing treatment, a method of rubbing the surface of the coating film for the alignment layer with a rubbing cloth such as paper, gauze, felt, rubber, nylon, or polyester fiber in a certain direction can be mentioned. Generally, a rubbing treatment such as rubbing the surface of the coating film for an alignment layer several times is performed using a rubbing cloth on which fibers of a uniform length and thickness are evenly transplanted.
As described above, the alignment layer having the orientation regulating force for the liquid crystal compound is formed.

(Liquid crystal layer and its formation method)
On the oriented layer formed as described above, a coating film of a material for forming a liquid crystal layer (hereinafter, also referred to as a coating film for a liquid crystal layer) is formed. After that, the liquid crystal compound in the liquid crystal layer coating film is oriented and fixed to obtain a liquid crystal layer (that is, an optically anisotropic layer).

-Material for forming a liquid crystal layer-
The material for forming a liquid crystal layer is a material containing a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound and cured by electron energy rays. The material for forming the liquid crystal layer may be a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound, as well as other known materials such as a polymerizable compound, a crosslinkable compound, a chiral agent, an orientation control agent, a polymerization initiator, and an orientation auxiliary, if necessary. May contain the components of.

-Stick-shaped liquid crystal compounds Examples of rod-shaped liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidins, and alkoxy-substituted ones. Phenylpyrimidines, phenyldioxans, trans and alkenylcyclohexylbenzonitriles are preferably used.
Not only low molecular weight liquid crystal molecules as described above, but also high molecular weight liquid crystal molecules can be used.

It is more preferable to fix the orientation of the rod-shaped liquid crystal compound by polymerization, and therefore it is preferable to use a rod-shaped liquid crystal compound having a polymerizable group.
Examples of the polymerizable rod-shaped liquid crystal compound include Makromol. Chem. , 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 562,648, 5770107, International Publication 95/22586, 95 / 24455, 97/00600, 98/23580, 98/52905, Japanese Patent Application Laid-Open No. 1-272551, 6-16616, 7-110469, 11- Examples thereof include compounds described in Japanese Patent Application Laid-Open No. 80081 and Japanese Patent Application Laid-Open No. 2001-328973.
Further, as the rod-shaped liquid crystal compound, for example, those described in JP-A No. 11-513019, JP-A-2007-279688, etc. can be preferably used.

-Disc-shaped liquid crystal compound As the disk-shaped liquid crystal compound, for example, those described in JP-A-2007-108732, JP-A-2010-2404038 and the like can be preferably used.

As the coating film for the liquid crystal layer, the same methods as the coating method and the drying method in the coating film forming step (1) or (2) described above can be used, and the preferred embodiment is also the same.
When the method for producing the optical film of the first embodiment and the second embodiment is the method for producing a retardation film, the formation of the coating film for the liquid crystal layer is the coating film forming step (1) described above or It corresponds to (2).

-Orientation of liquid crystal compounds-
Before fixing the orientation of the liquid crystal compound in the liquid crystal layer coating film, it is preferable to perform the orientation treatment of the liquid crystal compound in the liquid crystal layer coating film.
The orientation treatment can be performed by drying at room temperature or the like or by heating.
In the case of a liquid crystal compound having thermotropic properties, the liquid crystal formed by the orientation treatment can generally be transferred by a change in temperature or pressure. Further, in the case of a liquid crystal compound having a lyotropic property, it can be transferred by a composition ratio such as the amount of solvent.

When the rod-shaped liquid crystal compound expresses the smectic phase, the temperature range in which the nematic phase is expressed is usually higher than the temperature range in which the rod-shaped liquid crystal compound expresses the smectic phase. Therefore, the rod-shaped liquid crystal compound is heated to the temperature range in which the rod-shaped liquid crystal compound expresses the nematic phase, and then the heating temperature is lowered to the temperature range in which the rod-shaped liquid crystal compound expresses the smectic phase, whereby the rod-shaped liquid crystal compound is brought into the nematic phase. Can be transferred to the smectic phase. By setting the smectic phase in this way, a liquid crystal in which the liquid crystal compounds are oriented with high order can be obtained.

In the temperature range where the rod-shaped liquid crystal compound expresses the nematic phase, it is necessary to heat for a certain period of time until the rod-shaped liquid crystal compound forms a monodomain. The heating time is preferably 10 seconds to 5 minutes, more preferably 10 seconds to 3 minutes, and most preferably 10 seconds to 2 minutes.
In the temperature range in which the rod-shaped liquid crystal compound expresses the smectic phase, it is necessary to heat for a certain period of time until the rod-shaped liquid crystal compound expresses the smectic phase. The heating time is preferably 10 seconds to 5 minutes, more preferably 10 seconds to 3 minutes, and most preferably 10 seconds to 2 minutes.

The orientation of the liquid crystal compound may be performed by drying when forming the coating film for the liquid crystal layer. That is, in the drying when forming the coating film for the liquid crystal layer, both the drying of the material for forming the liquid crystal layer coated on the alignment layer and the orientation of the liquid crystal compound may be performed.
Of course, the orientation of the liquid crystal compound may be performed separately from the drying when forming the coating film for the liquid crystal layer.

-Fixing the orientation of liquid crystal compounds-
The orientation of the liquid crystal compound in the liquid crystal layer coating is preferably fixed by curing the liquid crystal layer coating by thermal polymerization or polymerization with active energy rays.
When the method for producing the optical film of the first embodiment and the second embodiment is the method for producing a retardation film, fixing the orientation of the liquid crystal compound using active energy rays is the curing step described above. It corresponds to 1) or (2).
When a polymerizable liquid crystal compound is used, if the irradiation amount of the active energy ray is small, the unpolymerized liquid crystal compound remains, which causes temperature change of optical characteristics, deterioration with time, and the like. Therefore, it is preferable to determine the irradiation conditions so that the proportion of the remaining unpolymerized liquid crystal compound is 5% or less.
The irradiation conditions, the formulation of the liquid crystal layer forming material, and depending on the thickness of the liquid crystal layer coating film, the active energy ray irradiation amount is ^{preferably 50mJ / cm 2 ~1000mJ / cm 2} , 100mJ / cm 2 ~ 500 mJ / cm ² is more preferable.

As the light source used for irradiating the active energy rays, the exposure light source in the coating film forming step (1) or (2) described above can be applied, and the preferred embodiment is also the same.

In addition, for details of the liquid crystal layer, the description of JP-A-2008-225281 and JP-A-2008-026730 can be referred to.

In the retardation film obtained as described above, wrinkles generated when the orientation of the liquid crystal compound is fixed are reduced.
Therefore, it can be a retardation film having excellent in-plane uniformity of optical performance.

An example of applying the methods for producing an optical film of the first embodiment and the second embodiment to obtain a liquid crystal layer of a retardation film has been described above, but in addition to the above-mentioned antireflection film. It can also be applied to obtain an antireflection layer, an antiglare layer of an antiglare film, a lenticular lens layer of a lenticular sheet, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[Examples 1 to 24 and Comparative Examples 1 to 2]
(Formation of coating film for alignment layer and rubbing treatment)
Alkyl-modified polyvinyl alcohol (Poval MP- A 2% by mass aqueous solution of 203, Kuraray Co., Ltd.) was ^{applied to 25 ml per 1 m 2} of a continuous film support and then dried at 60 ° C. for 60 seconds to form a coating film for an alignment film having a dry film thickness of 0.5 μm. Then, while transporting the continuous film support on which the coating film for the alignment film is formed at a transport speed of 30 m / min, the surface of the coating film for the alignment film is subjected to a rubbing treatment to form an alignment film having a thickness of 0.5 μm. bottom.

(Formation of coating film for liquid crystal layer: coating film forming process)
Subsequently, a coating film forming step, a preheating step, and a curing step were performed in an apparatus having each step as shown in FIG. 1 or FIG.
Specifically, a liquid crystal layer forming material prepared with the following composition was applied onto the alignment layer using a bar coater.
The continuous film support coated with the liquid crystal layer forming material was heated and dried at a film surface temperature of 150 ° C. for 60 seconds to form a liquid crystal layer coating film having a dry film thickness of 2 μm.

-Composition of material for forming liquid crystal layer-
Reverse wavelength dispersion liquid crystal compound R-2 100 parts by mass Photopolymerization initiator 3.0 parts by mass (Irgacure 819, BASF)
Fluorine-containing compound A 0.8 parts by mass Crosslinkable polymer O-2 (Tg: 10 ° C) 0.3 parts by mass Chloroform 588 parts by mass

(Preheating process)
Then, a continuous film support having a coating film for a liquid crystal layer was wound around a heating roll (diameter 600 mm) having a surface temperature shown in Table 1 below to heat the continuous film support having a coating film for a liquid crystal layer.

(Ultraviolet irradiation: curing process)
Subsequently, in the reaction chamber, a backup roll (diameter 500 mm, material stainless steel) was wrapped around the wrap angle at 90 ° C., and an air-cooled metal halide lamp (Igraphics Co., Ltd.) was applied to the coating film for the liquid crystal layer in the wrapped area. Used to irradiate ultraviolet light. The irradiation amount of ultraviolet rays was 300 mJ / cm ² .
^{Nitrogen gas was supplied into the reaction chamber at a supply amount of 100 m 3} / h from a slit-shaped outlet of 2 mm × 2000 mm, and nitrogen gas was applied over the entire width direction of the continuous film support. The slit-shaped outlet was installed so that the short (2 mm) side was along the transport direction of the continuous film support and the long (2000 mm) side was along the width direction of the continuous film support. Further, the slit-shaped outlet is installed at a position 5 mm away from the coating film surface at the contact point between the continuous film support and the backup roll, and the nitrogen gas discharge direction is substantially perpendicular to the coating film surface (in the case of FIG. 2). The direction shown by the arrow).
In the case of Examples 1 to 24, the nitrogen gas supplied to the reaction chamber was heated to the temperature shown in Table 1 below, and in the case of Comparative Examples 1 to 2, the nitrogen supplied to the reaction chamber was used. The gas was unheated.

As described above, the atmospheric temperature in the reaction chamber is the thermocouple installed at a position 1 mm away from the coating film surface at the contact point between the continuous film support and the backup roll in the reaction chamber (Ninomiya Electric Wire Industry Co., Ltd., Supermarket). It was measured with an extra-fine -01-K).

As described above, the curing step was carried out to fix the orientation of the liquid crystal compound and form a liquid crystal layer to obtain a retardation film.

[Example 25]
A retardation film was obtained in the same manner as in Example 5 except that the preheating step was not performed in Example 5.

[Example 26]
A retardation film was obtained in the same manner as in Example 5 except that the irradiation of ultraviolet rays in Example 5 was changed as follows.

(Ultraviolet irradiation)
In the reaction chamber, wrap it around a backup roll (diameter 500 mm, material stainless steel) at a wrap angle of 90 ° C. Was irradiated. The irradiation amount of ultraviolet rays was 150 mJ / cm ² .
A heated nitrogen gas at 100 ° C. was supplied into the reaction chamber from a slit-shaped outlet of 2 mm × 2000 mm with a supply amount of 100 m ^{3 / h.} As shown in FIG. 3, the slit-shaped outlet (36c in FIG. 3) is installed near the outlet of the reaction chamber at a position 50 mm away from the coating film surface, and the nitrogen gas discharge direction is the coating film. It was made to be substantially parallel to the surface and opposite to the transport direction.

[Evaluation: Occurrence of wrinkles]
The wrinkle state of the retardation films produced in the above Examples and Comparative Examples was evaluated based on the following methods and evaluation criteria.
The results are shown in Table 1.

The state of wrinkles was visually observed and evaluated in the entire width direction from 0 m to 1 m from the end (end on the winding end side) of the obtained retardation film.
More specifically, the retardation film is sandwiched between two polarizing plates, and the angle of the polarizing plate is adjusted while allowing transmitted light to be darkened as a whole to increase the intensity of light transmitted from the wrinkled portion. Observation was performed, and sensory evaluation was performed based on the observation.

-Evaluation criteria-
A: No wrinkles B: Wrinkles are slightly visible C: Wrinkles are visible, but there is no effect on the quality when mounted on products such as liquid crystal display devices D: Wrinkles are visible, for example, liquid crystal display There is a slight effect when mounted on products such as devices, but the quality of the product is at a practically acceptable level. E: Wrinkles are large or many, and the effect when mounted on products such as liquid crystal display devices is Large and product quality is impractical

In Table 1, the "thickness of the support" is the thickness of the continuous film support itself, and in Table 1, the "total thickness of the support and the coating film" is on the continuous film support and the continuous film support. It is the total thickness of the provided coating film, and "the degree of contact point between the support and the roll T _{1 " is the temperature T 1} at the contact point between the continuous film support and the backup roll, and "the surface of the roll". “Temperature T ₂ ” is the surface temperature T ₂ of the backup roll.

As is clear from Table 1, it can be seen that the retardation film of the example suppresses the occurrence of wrinkles as compared with the retardation film of the comparative example.
In particular, _{it can be seen that when the difference between the temperature T 1} and the temperature T ₂ is small and the temperature T ₁ is within ± 20 ° C. with respect to the temperature T ₂ , the occurrence of wrinkles is suppressed.
Further, it can be seen that the larger the total thickness t between the continuous film support and the coating film, the more wrinkles can be suppressed even if the difference between _{the temperature T 1} and the temperature T _{2 is large.}

1 Coating means 2 Drying means 3 Reaction chamber 4 Heating roll 32 Exposure light source 34 Backup roll 36a, 36b, 36c Nozzle (outlet)
F Continuous film support P Contact point between continuous film support and backup roll Q Separation point between continuous film support and backup roll

Claims (16)

A coating film forming step of forming a coating film cured by active energy rays on a continuous film support,
In the reaction chamber where the inert gas is supplied and filled and the internal atmosphere is heated by the heating means, the coating film is formed in the region where the continuous film support on which the coating film is formed is wound around the heated backup roll. The curing process of irradiating the film with active energy rays to cure the coating film,
In Yes, and curing step a method for producing an optical film in which the first contact point between the backup roll which is a heated continuous film support is in the reaction chamber. The method for producing an optical film according to claim 1, wherein the heating means for heating the internal atmosphere in the reaction chamber is the heating means for heating the inert gas. The method for producing an optical film according to claim 1 or 2, wherein the heating means heats the inert gas supplied to the reaction chamber to heat the internal atmosphere in the reaction chamber. A coating film forming step of forming a coating film cured by active energy rays on a continuous film support,
In the reaction chamber to which the inert gas is supplied and filled, the surface of the continuous film support on which the coating film is formed is heated, and the continuous film support on which the coating film is formed is wound on a heated backup roll. A curing step of irradiating the coating film with active energy rays in the applied area to cure the coating film,
In Yes, and curing step a method for producing an optical film in which the first contact point between the backup roll which is a heated continuous film support is in the reaction chamber. The method for producing an optical film according to claim 4, wherein the surface on which the coating film of the continuous film support is formed is heated by the heated inert gas. The fourth or fifth aspect of the present invention, wherein the heated inert gas is applied to the surface of the continuous film support on which the coating film is formed to heat the surface of the continuous film support on which the coating film is formed. A method for manufacturing an optical film. In the reaction chamber, a heated inert gas is applied to the surface on which the coating film of the continuous film support is formed up to the separation point between the continuous film support and the backup roll, and the coating film of the continuous film support is formed. The method for producing an optical film according to claim 6, wherein the formed surface is heated. In the reaction chamber, the surface on which the coating film of the continuous film support is formed up to the first contact point between the continuous film support and the backup roll is applied with a warmed inert gas to coat the continuous film support. The method for producing an optical film according to claim 6 or 7, wherein the surface on which the film is formed is heated. The method for producing an optical film according to any one of claims 1 to 8, wherein the total thickness of the continuous film support on which the coating film is formed is 3 μm or more and 115 μm or less. The method for producing an optical film according to any one of claims 1 to 9, wherein the surface temperature of the backup roll in the reaction chamber is 80 ° C. or higher and 250 ° C. or lower. The reaction chamber, if the temperature at the initial contact point between the continuous film support and the backup roll and T ₁ ° C., the surface temperature of the backup roll which is heated to a T ₂ ° C., T ₁ is T ₂ -20 ° C. The method for producing an optical film according to any one of claims 1 to 10, wherein the temperature is _{T 2 + 20 ° C. or lower.} The temperature at the first contact point between the continuous film support and the backup roll in the reaction chamber was set _{to T 1} ° C, the surface temperature of the heated backup roll was set to T ₂ ° C, and the continuous film support on which the coating film was formed was formed. The method for producing an optical film according to any one of claims 1 to 10, wherein the total thickness of the film is tμm, which satisfies the following formula (1).
Equation (1) 0 ≤ | T _2- T ₁ | ≤ t The production of the optical film according to any one of claims 1 to 12, further comprising a preheating step of heating the continuous film support on which the coating film is formed after the coating film forming step and before the curing step. Method. The temperature of the coating film surface of the continuous film support on which the coating film was formed in the preheating step or the surface opposite to the coating film surface is set to T. ₃ The temperature was set to ° C, and the surface temperature of the heated backup roll in the reaction chamber was set to T. ₂ At ° C, T ₃ Is T ₂ -20 ° C or higher T ₂ The method for producing an optical film according to claim 13, wherein the temperature is + 20 ° C. or lower. In the preheating step, the temperature of the coating film surface or the surface opposite to the coating film surface of the continuous film support on which the coating film is formed is raised to 60 ° C. to 250 ° C. by heating the continuous film support on which the coating film is formed. The method for producing an optical film according to claim 13 or 14. The method for producing an optical film according to any one of claims 1 to 15, wherein the coating film is a coating film of a material for forming a liquid crystal layer.

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