JP7004802B2 - Optical film manufacturing method - Google Patents

Description

The present disclosure relates to a method for manufacturing 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 continuous process in a roll-to-roll method using a long film-like support (hereinafter referred to as "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 and drying an active energy ray-curable resin composition on the surface of a continuous film support to form a coating film, and an activity on the formed coating film. A method comprising an active energy ray irradiation step of irradiating an energy ray to cure a coating film and forming a target optical functional layer on the surface of a continuous film support can be mentioned.
When an optical film is manufactured by a continuous process using a roll-to-roll method, the continuous film support comes into contact with various rolls, so that the width is prevented from shifting the transport position of the continuous film support. It is preferable to use a continuous film support having a portion where minute protrusions called knurled portions are formed along both ends in the direction.

For example, Japanese Patent Application Laid-Open No. 2017-32756 describes a layer having a first region formed by knurling on a base film and a layer having a fine concavo-convex structure formed between the first regions on the surface. A transparent film having a second region provided with a knurled film is disclosed. Further, as a method for producing this transparent film, the active energy ray-curable resin composition is coated on the base film on which the first region is formed in the second region, and the applied active energy ray-curable resin is applied. A method is disclosed in which a transfer mold is pressed against a composition and irradiated with active energy rays to cure the active energy ray-curable resin composition, and then the transfer mold is separated.

Further, for example, in Japanese Patent Application Laid-Open No. 2010-139824, a hard coat layer coating composition is applied on a long cellulose triacetate film that has been knurled, and after drying, the coating layer is applied with an ultraviolet lamp. A method of curing is disclosed.

When manufacturing an optical film, in the active energy ray irradiation step, the irradiation amount of the active energy ray applied to the coating film may be uneven in the width direction of the continuous film support. When the irradiation amount of the active energy ray in the width direction of the continuous film support is uneven, the amount of the active energy ray-curable resin composition applied in the width direction of the continuous film support is usually in the coating film forming step. Is adjusted according to the unevenness of the irradiation amount. Then, by this adjustment, the variation of the optical characteristics in the width direction of the manufactured optical film can be suppressed.
However, in the active energy ray irradiation step, when the transport position is displaced in the width direction of the continuous film support, the adjustment position of the coating amount of the active energy ray curable resin composition performed in the coating film forming step is performed. This causes a problem that it is difficult to suppress variations in optical characteristics in the width direction in the manufactured optical film. The deviation of the transport position in the width direction of the continuous film support is reduced by using, for example, a continuous film support having a knurling portion.
On the other hand, in the active energy ray irradiation step, a means of wrapping the continuous film support around the temperature control roll and irradiating the coating film on the temperature control roll with the active energy ray may be taken. This means can irradiate the coating film in a stretched state along the shape of the temperature control roll with active energy rays, and because the continuous film support is in contact with the temperature control roll, the continuous film support can be used. It is effective in that it is easy to control the temperature.
However, when a continuous film support having a knurling portion is used, if the knurling portion is in contact with the temperature control roll, only the widthwise end of the continuous film support may float due to the presence of the knurling portion. In the active energy ray irradiation step, if only the widthwise end of the continuous film support is floating, there will be a difference in the irradiation amount of the active energy ray between the center and the end in the width direction, and the optical film also manufactured. In, there arises a problem that the optical characteristics vary in the width direction.

In neither Japanese Patent Application Laid-Open No. 2017-32756 and Japanese Patent Application Laid-Open No. 2010-139824, it is not specified whether or not the knurled portion of the continuous film support is in contact with the temperature control roll, and in the active energy ray irradiation step, it is not specified. It has not been investigated at all that the transport position shifts in the width direction of the continuous film support or that only the width end of the continuous film support floats. Therefore, it is considered that the techniques described in JP-A-2017-32756 and JP-A-2010-139824 cause variations in optical characteristics in the width direction in the manufactured optical film as described above. Be done.

Therefore, the problem to be solved by one embodiment of the present invention has been made in view of the above circumstances, and the coating film is cured by irradiation with active energy rays using a continuous process in a roll-to-roll method. It is a method for manufacturing an optical film including a step, and an object of the present invention is to provide a method for manufacturing an optical film in which variations in optical characteristics in the width direction are reduced.

Means for solving the above problems include the following embodiments.
<1> A step of applying and drying the active energy ray-curable resin composition on the surface of a continuous film support having knurled portions along both ends in the width direction, which is continuously conveyed, to form a coating film. When,
A step of wrapping the surface of the continuous film support on which the coating film is formed, which is opposite to the surface having the knurled portion, in contact with the temperature control roll and irradiating the coating film on the temperature control roll with active energy rays. When,
A step of bringing the surface of the continuous film support having a knurled portion into contact with a roll member provided on the downstream side of the continuous film support in the transport direction from the temperature control roll.
Have,
The transport speed of the continuous film support on the temperature control roll is U, the viscosity of the air at the surface temperature of the temperature control roll is μ, the radius of the temperature control roll is R, the height of the knurling portion is h _k , and the temperature is high. When the tension applied to the continuous film on the adjusting roll is T and the distance from the separation point between the continuous film support and the temperature controlling roll to the contact point between the continuous film support and the roll member is L, the following relational expression A method for manufacturing an optical film that satisfies (1).

In the relational expression (1), the unit of U is m / min, the unit of μ is Pa · sec, the unit of h _k is m, the unit of R is m, and the unit of T is N / sec. m.

<2> The method for manufacturing an optical film according to <1>, wherein the transport speed U of the continuous film support on the temperature control roll is 5 m / min to 40 m / min.
<3> The method for producing an optical film according to <1> or <2>, wherein the radius R of the temperature control roll is 0.2 m to 0.4 m.
<4> The method for producing an optical film according to any one of <1> to <3>, wherein the surface temperature of the temperature control roll is 80 ° C. to 160 ° C.

<5> The method for producing an optical film according to any one of <1> to <4>, wherein the height h _k of the knurled portion of the continuous film support is 1 μm to 20 μm.
<6> The method for producing an optical film according to any one of <1> to <5>, wherein the tension T applied to the continuous film on the temperature control roll is 100 N / m to 600 N / m.

<7> The method for producing an optical film according to any one of <1> to <6>, wherein the thickness of the portion where the knurled portion of the continuous film support is not formed is 20 μm to 100 μm.
<8> The method for manufacturing an optical film according to any one of <1> to <7>, wherein the width length of the continuous film support is 50 mm to 2000 mm.
<9> The method for manufacturing an optical film according to any one of <1> to <8>, wherein the radius of the roll member is 20 mm to 70 mm.

According to one embodiment of the present invention, there are variations in optical characteristics in the width direction in a method for producing an optical film, which comprises a step of curing a coating film by irradiation with active energy rays using a continuous process in a roll-to-roll method. A method for manufacturing an optical film in which the amount of energy is reduced is provided.

It is a schematic diagram which shows each process of the manufacturing method of the optical film of one Embodiment. It is a top view of the continuous film support used in the manufacturing method of the optical film of one Embodiment. It is an enlarged sectional view of the knurling part in the continuous film support used in the manufacturing method of the optical film of one Embodiment.

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 one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. 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 shown in this disclosure is not necessarily on an exact scale, with a focus 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, the "width direction" refers to a direction orthogonal to the longitudinal direction of a long continuous film support and an optical film.
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

≪Manufacturing method of optical film≫
The present inventors have investigated a method for producing an optical film including a step of curing a coating film by irradiation with active energy rays using a continuous process of a roll-to-roll method. It has been found that the variation in optical characteristics in the width direction is reduced.
That is, in the method for producing an optical film of one embodiment, the active energy ray-curable resin composition is applied to the surface of a continuous film support having a knurling portion along both ends in the width direction, which is continuously conveyed. A temperature control roll is formed on the surface opposite to the surface of the continuous film support on which the coating film is formed, which is opposite to the surface having the nerling portion. A step of irradiating the coating film on the temperature control roll with active energy rays (hereinafter also referred to as "active energy ray irradiation step") and a surface of the continuous film support having a nerling portion. The continuous film on the temperature control roll has a step of contacting the roll member provided on the downstream side of the continuous film support in the transport direction with respect to the temperature control roll (hereinafter, also referred to as "nulling portion contact step"). The transport speed of the support is U, the viscosity of the air at the surface temperature of the temperature control roll is μ, the radius of the temperature control roll is R, the height of the _narling portion is hk, and the continuous film on the temperature control roll is formed. When the applied tension is T and the distance from the separation point between the continuous film support and the temperature control roll to the contact point between the continuous film support and the roll member is L, the following relational expression (1) is satisfied. This is a film manufacturing method.

In the relational expression (1), the unit of U is m / min, the unit of μ is Pa · sec, the unit of h _k is m, the unit of R is m, and the unit of T is N / sec. m.

In the above method for manufacturing an optical film, a continuous film support having a knurling portion is used. Then, the continuous film support is wound by bringing the surface opposite to the surface having the knurled portion into contact with the temperature control roll, and in that region, the coating film on the temperature control roll is irradiated with active energy rays. do. By adopting this method, in the active energy ray irradiation step, only the end in the width direction does not float in the continuous film support on the temperature control roll. Therefore, it is possible to suppress the difference in the irradiation amount of the active energy rays caused by this floating between the central portion and the terminal portion in the width direction.
Further, in the above-mentioned optical film manufacturing method, in the knurling portion contacting step, the continuous film support is provided with a surface having the knurling portion on the downstream side of the continuous film support in the transport direction with respect to the temperature control roll. Contact the member. In the knurling portion contacting step, the contact of the knurling portion with the roll member prevents the transport position from shifting in the width direction of the continuous film support.
Here, by satisfying the relational expression (1), even in the active energy ray irradiation step performed on the upstream side in the transport direction of the continuous film support from the knurling portion contact step, the film is transported in the width direction of the continuous film support. It is possible to prevent the position from shifting.

The details of the above relational expression (1) will be described.
In the relational expression (1), ha is generated because air is _entrained between the continuous film support and the temperature control roll when the continuous film support is wound on the temperature control roll in the active energy ray irradiation step. , Corresponds to the thickness of the air layer (so-called air film) between the continuous film support and the temperature control roll.
The larger the thickness _ha of this air film, the more likely it is that the transport position shift of the continuous film support on the temperature control roll will occur.
On the other hand, h _k indicates the height of the knurled portion of the continuous film support. _If the height h _k of the knurling portion becomes smaller than the thickness ha of the air film, the effect of suppressing the transfer position shift due to the contact between the knurling portion and the roll member in the knurling portion contacting process becomes difficult to be obtained. That is, if the height h _k of the _knurling portion becomes smaller than the thickness ha of the air film, the grip force of the knurling portion with respect to the roll member does not function easily, and the transfer position deviation cannot be sufficiently suppressed. ..
Therefore, the present inventors paid attention to " _a value obtained by dividing the thickness h _a of the air film by the height h _k of the knurling portion (that is, the value of ha / h _k )", and this value and the transport position deviation. Considering that there is a correlation with the likelihood of occurrence, we conducted a survey. As _a result, when the relationship between the "value of ha / h _k " and the "displacement amount of the transport position" was investigated, the coefficient "2.38" and the multiplier "0" were given to the "value of _ha / h _k ". When ".9" was applied, a correlation was obtained between the distance L from the separation point between the continuous film support and the temperature control roll and the contact point between the continuous film support and the roll member. I came to find (1).
When the above relational expression (1) is satisfied, it is possible to prevent the transport position from being displaced in the width direction of the continuous film support in the active energy ray irradiation step.

Here, "U", "μ", and "T" in the relational expression (1) will be described.
“U (unit: m / min)” in the relational expression (1) is a continuous film on the temperature control roll (that is, a continuous film from the contact point with the temperature control roll to the separation point with the temperature control roll). Refers to the transport speed of the support).
“Μ (unit: Pa · sec)” in the relational expression (1) refers to the viscosity of air at the surface temperature of the temperature control roll. The viscosity of air in the present disclosure is a value calculated by calculation based on the literature value or the literature value described in "Fluid Dynamics (Corona Publishing Co., Ltd., 2002)".
“T (unit: N / m)” in the relational expression (1) is a continuous film on the temperature control roll (that is, a continuous film support from the contact point with the temperature control roll to the separation point with the temperature control roll). ) In the longitudinal direction (that is, the transport direction), that is, the tension.

As a result of the above, according to the method for manufacturing an optical film of one embodiment, it is possible to manufacture an optical film in which variations in optical characteristics in the width direction are reduced.

Hereinafter, the details of the coating film forming step, the active energy ray irradiation step, and the nerling portion contacting step in the method for manufacturing an optical film of one embodiment will be described.
Here, a cured film is formed on the continuous film support through the coating film forming step and the active energy ray irradiation step. The cured film formed becomes an optical functional layer (for example, an optically anisotropic layer, an antireflection layer, an antiglare layer, etc.) in the optical film.

[Coating film forming process]
In the coating film forming step, the active energy ray-curable resin composition is applied and dried on the surface of the continuous film support having knurling portions along both ends in the width direction, which is continuously conveyed, to form a coating film. Form.

An example of the coating film forming step will be described with reference to FIG.
As shown in FIG. 1, when the tip of the wound continuous film support 10 is sent out, the active energy ray-curable resin composition is first applied to the surface opposite to the surface having the knurled portion by the coating means 1. Is applied, and then dried in the drying area by the drying means 2. In this way, a coating film obtained by applying and drying the active energy ray-curable resin composition is formed on the continuous film support.
In the active energy ray irradiation step described later, the continuous film support brings the surface opposite to the knurling portion into contact with the temperature control roll. Therefore, in the present coating film forming step, the surface on which the active energy ray-curable resin composition is applied is the surface having the knurled portion of 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, Polyethylene and other polyolefins, Polyethylene terephthalate, Polyethylene naphthalate and other polyesters, Polyethersulfone, Polymethylmethacrylate and other acrylic resins, 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))) and so on.
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 and the like.

The thickness of the portion where the knurled portion of the continuous film support is not formed may be determined according to the manufacturing suitability, application, etc., and is preferably in the range of 3 μm to 250 μm, for example. The thickness of the continuous film support is more preferably 20 μm or more from the viewpoint of high applicability to winding on the temperature control roll.
In particular, when the thickness of the continuous film support is thin, the transfer position tends to be displaced. However, by satisfying the relational expression (1), a thin continuous film support in the range of 20 μm to 100 μm can be obtained. It can be preferably used.
From the viewpoint of material cost, the thickness of the continuous film support is preferably 80 μm or less.
From the above, the thickness of the continuous film support is preferably 20 μm to 80 μm, more preferably 20 μm to 60 μm.

The width and length of the continuous film support may be determined according to manufacturing suitability, application, etc., and is preferably in the range of, for example, 50 mm to 2000 mm. The larger the width, the greater the influence of the displacement of the transport position. However, by satisfying the relational expression (1), a continuous film support having a width of 800 mm to 1500 mm can be preferably used.

The continuous film support has knurled portions along both ends in the width direction, as shown in FIG. 2A.
Here, the "knurling portion" means a portion (12 in FIG. 2A) of the continuous film support in which minute protrusions as shown in FIG. 2B are provided.

The height of the knurled portion (that is, h _k in the relational expression (1)) is preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm, and 4 μm to 10 μm from the viewpoint of preventing the transfer position of the continuous film support from shifting. More preferred.
The height of the knurled portion is 5000 mm from the tip in the longitudinal direction of the continuous film support in the knurled portion of the continuous film support (that is, one at each end in the width direction), and It refers to the average value of the maximum heights at two locations (that is, one at each end in the width direction) of 5000 mm from the end in the longitudinal direction of the continuous film support, for a total of four locations.
The specific measurement method is as follows.
First, the thickness of the continuous film support is continuously measured from the inside to the outside by 100 mm from both ends in the width direction of the continuous film support at a position of 5000 mm from the tip in the longitudinal direction of the continuous film support. By this measurement, the thickness of the continuous film support can be measured from the portion where the knurling portion is not formed to the region where the knurling portion is formed and the thickness is large. Then, the average value of the thickness of the portion where the knurling portion is not formed is subtracted from the largest value measured in the region where the knurling portion is formed and the thickness is large, that is, the thickness of the portion having the largest thickness. Let the value be the maximum height. This is the maximum height of the knurled portion of the continuous film support at two locations (that is, one at each end in the width direction) of 5000 mm from the longitudinal tip of the continuous film support.
Subsequently, the same measurement as above is performed at a position of 5000 mm from the end in the longitudinal direction of the continuous film support to obtain the maximum height. This is the maximum height of the knurled portion of the continuous film support at two locations (that is, one at each end in the width direction) of 5000 mm from the longitudinal end of the continuous film support.
Here, a contact type thickness measuring instrument (Fujiwork Co., Ltd., S-2270) is used for the measurement. A strip with a width of 5 mm including a position of 5000 mm from the tip or end of the continuous film support in the longitudinal direction is applied to the contact-type thickness measuring device for measurement.

Here, the ratio of the sum of the widths of the knurled portions (w1 + w2 in FIG. 2A) supports the continuous film from the viewpoint of developing the function of preventing the displacement of the transport position, ensuring the effective width as a product, and improving the yield. The range of 0.5% to 5.0% is preferable, and the range of 0.7% to 4.0% is more preferable with respect to the total width of the body.

The distance from the widthwise end of the continuous film support to the knurled portion is preferably 0 mm to 15 mm.
Here, the distance from the widthwise end of the continuous film support to the knurled portion is the distance from the widthwise end of the continuous film support to the widthwise outer end of the knurled portion (distance d in FIG. 2A). Equivalent to). That is, as shown in FIG. 2A, the knurling portion is preferably formed at a position where the distance d from each end portion in the width direction of the continuous film support is 0 mm to 15 mm. The distance d from the widthwise end of the continuous film support to the knurled portion is generally 0 mm or more because the knurled portion is easy to form, the effective width as a product is secured, and the yield is improved. It may be 20 mm, preferably 0 mm to 15 mm, and more preferably 2 mm to 15 mm.

The protrusions in the knurling portion are formed according to the shape of the convex portion of the knurling roll pressed against the continuous film support when the knurling portion is formed. The shape of the convex portion includes a pyramid base, a truncated cone, and the like.
For example, if the shape of the convex portion of the narling roll is a quadrangular pyramid (that is, a shape in which the quadrangular pyramid is cut in a plane parallel to the bottom surface and the pyramid portion having the apex is removed), the continuous film support is also a quadrangle. A convex portion (nerling) is formed along the shape of.
The convex portion formed on the continuous film support may have a shape in which only the edge portion in the shape of the convex portion of the knurling roll protrudes.

The number of convex portions (knurling) formed on the continuous film support is continuous from the viewpoint of developing grip force on the roll member and ensuring the strength of the continuous film support in the region where the knurling portion is formed. When the knurling portion of the film support is viewed from above, the number is preferably 10 to 200 per 1 cm ² , and more preferably 80 to 150 per 1 cm ² .
The method of observing the convex portions and obtaining the number of the convex portions can be performed by the following method.
That is, since the convex portions are continuously arranged to form the knurled portion, the number of the repeating minimum units is referred to as the number of convex portions (also referred to as "convex portion density").
The number of protrusions (convex density) is two at the tip in the longitudinal direction (that is, one at each end in the width direction) and two at the end in the narling portion of the continuous film support. (That is, one place at each end in the width direction), 5 mm square is observed and counted with a 5x magnifying glass for a total of 4 places, and the average value of each measurement point is multiplied by 4. The obtained value is rounded off to the first decimal place, and this is taken as the number of convex portions (convex portion density).
The measurement points are 5000 mm from the tip in the longitudinal direction of the continuous film support, two points of 5 mm square including each of both outer ends of the knurled portion in the width direction, and the end in the longitudinal direction of the continuous film support. There are two places of 5 mm square including each of both outer ends of the knurled portion in the width direction at 5000 mm.
When the width of the knurled portion is less than 5 mm, the number of convex portions (convex portion density) is counted by observing the maximum length square including both outer ends of the knurled portion with a 5x magnifying glass. It may be converted into a number per 1 cm ² . For example, if the width of the knurled portion is 3 mm, the number of convex portions (convex portion density) is counted by observing 3 mm squares at 4 locations with a 5x magnifying glass, and the average value of each measurement location is 100/9. Just double it. The obtained value is rounded off to the first decimal place, and this is taken as the number of convex portions (convex portion density).

As shown in FIG. 2A, the knurling portion may be formed by a single band from the tip to the end in the longitudinal direction of the continuous film support along both ends of the continuous film support, but the knurling portion may be formed. As long as the sum of the widths does not deviate from the above range, it may be formed by a plurality of bands.

The method for forming the knurling portion is not particularly limited, and a known knurling device can be used.
Specifically, as the knurling device, the device described in JP-A-2014-21801 can be used.

-Apply-
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. An example is a coating device using the bar method or the like.

-Drying-
Known drying means are applied to the drying.
Specific examples of the drying means include 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 opposite to the surface on which the coating liquid of the continuous film support is applied, and the surface of the applied coating liquid is diffused so as not to flow with the warm air. It may be configured by installing a board.
The drying conditions may be determined according to the type of coating liquid used, the coating amount, the transport speed, and the like, and are preferably carried out in the range of, for example, 30 ° C. to 140 ° C. for 10 seconds to 10 minutes.

Through the above coating film forming step, an uncured coating film that is cured by active energy rays is formed.
The thickness of the coating film obtained through the coating film forming step may be determined according to the use of the optical film. If the coating film is a liquid crystal layer coating film described later, the film thickness of the coating film after drying (so-called dry film thickness) to be subjected to the active energy ray irradiation step may be 0.5 μm to 10 μm. It is preferably 1 μm to 5 μm, and more preferably 1 μm to 5 μm.
Further, in the coating film forming step, when forming a coating film for a liquid crystal layer to be described later, the film thickness immediately after coating (so-called wet film thickness) is preferably 3 μm to 30 μm, preferably 5 μm to 15 μm. Is more preferable.

[Active energy ray irradiation process]
In the activation energy ray irradiation step, the surface of the continuous film support on which the coating film is formed, which is opposite to the surface having the nerling portion, is brought into contact with the temperature control roll and wound around the coating film on the temperature control roll. Irradiate with active energy rays.

An example of the active energy ray irradiation step will be described with reference to FIG.
As shown in FIG. 1, the continuous film support 10 on which the coating film is formed is wound around the temperature control roll 34, and in this region, the coating film on the temperature control roll 34 is activated by the exposure light source 32. The energy ray is irradiated.
At this time, the surface of the continuous film support 10 opposite to the knurled portion is in contact with the temperature control roll 34. Therefore, the widthwise end portion of the continuous film support 10 is lifted by the knurling portion with respect to the temperature control roll 34 and does not float.
Here, in FIG. 1, P indicates a contact point between the continuous film support 10 and the temperature control roll 34, and Q indicates a separation point between the continuous film support 10 and the temperature control roll 34. That is, the continuous film support 10 is in contact with the temperature control roll 34 from the contact point P to the separation point Q.

-Active energy ray-
The active energy ray used in the active energy ray irradiation step is not particularly limited as long as it can impart energy capable of generating active species to the irradiated coating film. 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 active energy ray irradiation step from the viewpoint of curing sensitivity and availability of the apparatus.

-Exposure light source-
Examples of the exposure light source used for irradiating the active energy ray in the active energy ray irradiation step include the above-mentioned light source for irradiating the active energy ray. From the viewpoint of curing sensitivity and availability of the apparatus, a light source that irradiates ultraviolet rays is preferable as the exposure light source.
Examples of the light source for irradiating 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, etc.). Examples thereof include an argon ion laser, a helium cadmium laser, a YAG (Yttrium Aluminum Garnet) laser), a light emitting diode, and a cathode wire tube.
The peak wavelength of ultraviolet rays emitted from a light source that irradiates ultraviolet rays is preferably 200 nm to 400 nm.

-Temperature control roll The temperature control roll used in the activation energy ray irradiation step is not particularly limited, and known ones can be used.
As the temperature control 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.
Further, the surface roughness of the temperature control roll is preferably 0.1 μm or less in terms of the surface roughness Ra from the viewpoint of reducing the variation in the frictional force between the continuous film support and the temperature control roll.

The surface temperature of the temperature control 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., preferably 60 ° C to 250 ° C, preferably 80 ° C to 160 ° C. More preferably, 80 ° C to 140 ° C is further preferable.
By setting the surface temperature of the temperature control 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. Further, the viscosity of air in the relational expression (1) changes depending on the surface temperature of the temperature control roll.
The surface temperature of the temperature control roll is measured as follows.
That is, the surface temperature of the surface of the temperature control roll is measured with a radiation thermometer (for example, FT-H30 manufactured by KEYENCE CORPORATION) at any five points in the width direction of the temperature control roll. The average value of the measured values is taken as the surface temperature of the temperature control roll.

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

The radius of the temperature control roll (that is, R in the relational expression (1)) is that the continuous film support is easy to wind, the activation energy ray is easy to irradiate, and the manufacturing cost of the temperature control roll is high. Therefore, 0.1 m to 0.5 m is preferable, and 0.2 m to 0.4 m is more preferable.

In the activation energy ray irradiation step, since the irradiation of the active energy ray is performed on the continuous film support in a stretched state, the longitudinal direction (that is, the transport direction) with respect to the continuous film support around which the temperature control roll is wound. Tension (also called tension) is applied to.
The tension applied to the continuous film support on the temperature control roll (that is, T in the relational expression (1)) is preferably 100 N / m to 700 N / m, more preferably 100 N / m to 650 N / m, and 300 N / m. -600 N / m is more preferable, and 400 N / m to 600 N / m is particularly preferable.
Since the tension (that is, tension) applied in the longitudinal direction of the continuous film support on the temperature control roll cannot be directly measured, the value measured as follows is adopted.
That is, the tension sensor provided on the downstream side of the continuous film support in the transport direction (for example, at a position 5000 mm away from the separation point between the continuous film support and the temperature control roll) with respect to the temperature control roll is used on the temperature control roll. Measure the tension applied in the longitudinal direction of the continuous film support at. Here, as the tension sensor, for example, a tension sensor having a built-in load cell is suitable, and specific examples thereof include an MB tension sensor manufactured by Nireco Corporation.

The transport speed of the continuous film support on the temperature control roll (that is, U in the relational expression (1)) is 5 m / from the viewpoint of ensuring productivity and improving the accuracy of irradiation of active energy rays. It is preferably min to 40 m / min or less, more preferably 10 m / min to 30 m / min or less, and further preferably 15 m / min to 25 m / min or less.
Since the transport speed of the continuous film support on the temperature control roll matches the rotation speed of the temperature control roll (so-called peripheral speed), the value of the rotation speed of the temperature control roll may be adopted.

The lap angle of the continuous film support with respect to the temperature control roll is preferably 60 ° or more, more preferably 90 ° or more.
The upper limit of the lap angle is, for example, 180 °.
The lap angle is the transport direction of the continuous film support when the continuous film support comes into contact with the temperature control roll, and the transport direction of the continuous film support when the continuous film support is separated from the temperature control roll. , The angle consisting of.

Through the above active energy ray irradiation step, the coating film is cured, and a cured film (that is, an optical functional layer) is formed on the continuous film support.

[Knurling part contact process]
In the knurling portion contacting step, the surface of the continuous film support having the knurling portion is brought into contact with the roll member provided on the downstream side of the continuous film support in the transport direction with respect to the temperature control roll.

An example of the knurling portion contacting process will be described with reference to FIG.
As shown in FIG. 1, the continuous film support 10 on which the coating film is formed is separated from the temperature control roll 34 and then wound around the roll member 4.
At this time, the knurling portion of the continuous film support 10 is in contact with the roll member 4, and the grip performance of the knurling portion to the roll member 4 is exhibited, and the displacement of the transport position of the continuous film support 10 is suppressed. ..
Here, in FIG. 1, S indicates a contact point between the continuous film support 10 and the roll member 4. That is, the distance L from the separation point between the continuous film support and the temperature control roll to the contact point between the continuous film support and the roll member means the distance from the separation point Q in FIG. 1 to the contact point S.

-Roll member-
The roll member may be provided at a position satisfying the relational expression (1).
That is, the distance L from the separation point between the continuous film support and the temperature control roll to the contact point between the continuous film support and the roll member is 2.38 × (ha _a / h _k ) ⁰ in the relational expression (1). It may be provided so as to be less than ^0.9 .
By providing the roll member at the position as described above, it is possible to prevent the transport position from being displaced in the width direction of the continuous film support in the above-mentioned active energy ray irradiation step.

As the roll member, a known transfer roll can be used without particular limitation.
The material of the roll member is not particularly limited, and the surface may be plated.
As the roll member, for example, the surface roughness, for example, 0.4 μm to 1.6 μm at the maximum height Rz is preferable in order to suppress the deviation of the transport position due to the knurling portion.

The radius of the roll member is preferably 10 mm to 100 mm, more preferably 20 mm to 70 mm, from the viewpoint of easy winding of the continuous film support, the development of grip force by the knurled portion, and the like.

The lap angle of the continuous film support with respect to the roll member is preferably 60 ° or more, and more preferably 90 ° or more, from the viewpoint of easily suppressing the deviation of the transport position in the width direction of the continuous film support.
The upper limit of the lap angle is, for example, 180 °.

After the above knurling portion contacting step, the continuous film support on which the cured film (that is, the optical functional layer) is formed is wound into a roll, for example, as shown in FIG.

Examples of the optical functional layer formed by the method for producing an optical film of one 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.
That is, according to the method for manufacturing an optical film of one embodiment, a retardation film having an optically anisotropic layer, an antireflection film having an antireflection layer, an antiglare film having an antiglare layer, and the like can be mentioned.

[Manufacturing method of retardation film]
Hereinafter, a method for manufacturing a retardation film will be described as an example of a method for manufacturing an optical film according to an embodiment.
The retardation film is an optically anisotropic layer containing an oriented and immobilized liquid crystal compound and an alignment layer having an orientation restricting 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 the alignment restricting force is applied to arrange the liquid crystal compounds of 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 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 to regulate the orientation of the coating film with respect to a liquid crystal compound. 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 alignment 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 / methacrylic acid. Polymers, styrene / maleinimide copolymers, polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyl toluene copolymers, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefins, polyesters, polyimides, 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 oriented 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 above-mentioned coating film forming step 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 in a fixed direction with a rubbing cloth.
The rubbing treatment is not particularly limited, and a known method can be applied. Specifically, as a rubbing treatment, a method of rubbing the surface of the coating film for an 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 in which fibers of uniform length and thickness are transplanted on average.
As described above, an alignment layer having an orientation regulating force with respect to the liquid crystal compound is formed.

(Liquid crystal layer and its formation method)
On the alignment 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).
When the method for producing an optical film of one embodiment is a method for producing a retardation film, the formation of a coating film for a liquid crystal layer corresponds to the above-mentioned coating film forming step, and is used for forming a coating film for a liquid crystal layer. The liquid crystal layer forming material used corresponds to an active energy ray-curable resin composition.

-Material for forming a liquid crystal layer-
The liquid crystal layer forming material is a material that contains a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound and is 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 aid, if necessary. It may contain the component of.

-Stick-shaped liquid crystal compounds Examples of the rod-shaped liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted compounds. Phenylpyrimidines, phenyldioxans, trans and alkenylcyclohexylbenzonitriles are preferably used.
Not only small molecule 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. No. 4,683,327, 5,622,648, 5770107, International Publication 95/22586, 95. / 24455, 97/00600, 98/23580, 98/52905, Japanese Patent Application Laid-Open No. 1-272551, No. 6-16616, No. 7-110469, No. 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 also be preferably used.

-Disc-shaped liquid crystal compound As the disc-shaped liquid crystal compound, for example, those described in JP-A-2007-108732, JP-A-2010-244038 and the like can be preferably used.

As the liquid crystal layer coating film, the same methods as the coating method and the drying method in the above-mentioned coating film forming step can be used, and the preferred embodiment is also the same.

-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 alignment treatment can be performed by drying or heating at room temperature or the like.
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 region in which the nematic phase is expressed is usually higher than the temperature region 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 forming the smectic phase by such a method, a liquid crystal in which the liquid crystal compound is 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 at the time of forming the coating film for the liquid crystal layer.

-Fixing the orientation of liquid crystal compounds-
It is preferable to fix the orientation of the liquid crystal compound in the liquid crystal layer coating film by curing the liquid crystal layer coating film by thermal polymerization or polymerization with active energy rays.
When the method for producing an optical film of one embodiment is a method for producing a retardation film, fixing the orientation of the liquid crystal compound using active energy rays corresponds to the above-mentioned active energy ray irradiation step.
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 ratio of the remaining unpolymerized liquid crystal compound is 5% or less.
The irradiation conditions depend on the formulation of the material for forming the liquid crystal layer and the thickness of the coating film for the liquid crystal layer, but the amount of active energy rays irradiated is preferably 50 mJ / cm ² to 1000 mJ / cm ² , preferably 100 mJ / cm ² to. 500 mJ / cm ² is more preferable.

As the light source used for irradiating the active energy rays, the exposure light source in the above-mentioned coating film forming step can be applied, and the preferred embodiment is also the same.

In addition, the details of the liquid crystal layer can be referred to in JP-A-2008-22281 and JP-A-2008-026730.

The retardation film obtained as described above has little variation in optical characteristics (for example, lettering) in the width direction.
Therefore, it can be a retardation film having excellent in-plane uniformity of optical characteristics (for example, letteration).

An example of applying the method for producing an optical film of one embodiment to obtain a liquid crystal layer of a retardation film has been described above. In addition, the antireflection layer of the antireflection film and the antiglare film described above have been described. It can also be applied when obtaining an antiglare layer or 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.

<Continuous film support with knurling part>
[Continuous film support (1)-(3)]
A continuous film support (cellulose triacetate film TJ40, FUJIFILM Corporation) on which the knurled portion shown in Table 1 below was formed was prepared.
The width length of the prepared continuous film support was 1.34 m, and the length was 1000 m.
In Table 1, the "number of bands" is the number of bands formed by the narling portion formed from the tip to the end in the longitudinal direction of the continuous film support along one end in the width direction of the continuous film support. The "convex density" means the number of convex portions existing per 1 cm ² when the nerling portion of the continuous film support is viewed from above, and the "thickness" means the continuous film support. The thickness of the portion where the knurling portion is not formed is shown.

[Measurement of knurling part]
For the continuous film supports (1) to (3), the height of the knurled portion and the number of convex portions (“convex portion density”) were measured as described above.
The measurement results are shown in Table 1.

[Example 1]
(Formation of coating film for alignment layer and rubbing treatment)
A continuous film support with a length of 1000 m, a width of 1340 mm, and a 2% by mass aqueous solution of alkyl-modified polyvinyl alcohol (Poval MP-203, Kuraray Co., Ltd.) on one side (the side having a knurling portion) of the continuous film support (1). After applying 25 ml per 1 m ² , it was dried at 60 ° C. for 60 seconds to form a coating film for an alignment layer having a dry film thickness of 0.5 μm. Then, while transporting the continuous film support on which the coating film for the alignment layer is formed at a transport speed of 30 m / min, the surface of the coating film for the alignment layer is subjected to a rubbing treatment to form an alignment layer having a thickness of 0.5 μm. did.

(Formation of coating film for liquid crystal layer: coating film forming process)
Subsequently, a coating film forming step, an active energy ray irradiation step, and a knurling portion contacting step were performed with the apparatus configured as shown in 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-
The following inverse wavelength dispersion liquid crystal compound R-2: 100 parts by mass Photopolymerization initiator: 3.0 parts by mass (Irgacure 819, BASF)
The following fluorine-containing compound A: 0.8 parts by mass The following crosslinkable polymer O-2 (Tg: 10 ° C): 0.3 parts by mass Chloroform: 588 parts by mass

(Irradiation of ultraviolet rays: activation energy ray irradiation process)
Subsequently, a continuous film support on which a coating film for a liquid crystal layer was formed was placed on a temperature control roll (radius R: 0.3 m, material stainless steel) having a surface temperature of 120 ° C., and a surface having a narling portion on the temperature control roll. Wrapped at a lap angle of 90 ° with the opposite surfaces in contact. Then, the coating film for the liquid crystal layer in the wound region was irradiated with ultraviolet rays using an air-cooled metal halide lamp (Igraphics) to fix the orientation of the liquid crystal compound, and a liquid crystal layer was obtained. The irradiation amount of ultraviolet rays was 300 mJ / cm ² .
Here, the transport speed U of the continuous film support on which the coating film for the liquid crystal layer is formed on the temperature control roll is 20 m / min, and the continuous film support on which the coating film is formed on the temperature control roll is formed. The tension T applied in the longitudinal direction was 450 N / m.
Here, the viscosity μ of air at a surface temperature of 120 ° C. of the temperature control roll was set to 2.299 × ^10-5 Pa · sec.

(Knurling part contact process)
After the activation energy ray irradiation step, the continuous film support on which the liquid crystal layer is formed is conveyed to the roll member (radius 50 mm, material stainless steel) side, and the narling portion on the same surface as the liquid crystal layer is brought into contact with the roll member. , Wrapped at a lap angle of 90 °.
The distance L from the separation point between the continuous film support and the temperature control roll to the contact point between the continuous film support and the roll member was 2 m.

As described above, the retardation film of Example 1 was obtained.
Each condition in Example 1 is summarized in Table 2.

[Examples 2 to 7 and Comparative Examples 1 to 8]
The continuous film support (1) was replaced with any of the continuous film supports (2) to (3) shown in Table 2 below, and / or the values of each condition were changed to the values shown in Table 2 below. A retardation film was produced in the same manner as in Example 1 except for the above.

[Evaluation: Evaluation of variations in optical characteristics]
With respect to the retardation films produced in the above Examples and Comparative Examples, the variation in optical characteristics in the width direction was evaluated based on the following method and evaluation criteria. The results are shown in Table 2.

13 points in the width direction (specifically, from one end in the width direction) at three locations of 1 m, 500 m, and 999 m in the longitudinal direction from the end (that is, the end on the winding end side) of the obtained retardation film. Letterings were measured at 6 points at 100 mm intervals, 1 point at 50 mm intervals, 1 point at 50 mm intervals, and 5 points at 100 mm intervals, for a total of 13 points).
The difference between the maximum value and the minimum value was obtained from the measured values of the lettering at 13 points in the width direction, and the one having the maximum difference among the above three points was evaluated. The larger the difference, the larger the variation in optical characteristics in the width direction.
For measurement of letteration, automatic birefringence index meter (KOBRA-21ADH, Oji Measuring Instruments Co., Ltd.)

As is clear from Table 2, it can be seen that the retardation film of the example suppresses the variation in the optical characteristics in the width direction as compared with the retardation film of the comparative example.

[Explanation of sign]
1 Applying means 2 Drying means 10 Continuous film support 12 Knurling part 32 Exposure light source 34 Temperature control roll 4 Roll member d Distance from each end of the continuous film support of the knurling part in the width direction w1 knurling part width w2 Narling part Width P Contact point between continuous film support and temperature control roll Q Separation point between continuous film support and temperature control roll S Contact point between continuous film support and roll member

The disclosure of Japanese application 2018-062709 filed on 28 March 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated by reference herein.

Claims (9)

A step of applying and drying the active energy ray-curable resin composition on the surface of a continuous film support having knurled portions along both ends in the width direction, which is continuously conveyed, to form a coating film.
A step of wrapping the surface of the continuous film support on which the coating film is formed, which is opposite to the surface having the knurled portion, in contact with the temperature control roll and irradiating the coating film on the temperature control roll with active energy rays. When,
A step of bringing the surface of the continuous film support having a knurled portion into contact with a roll member provided on the downstream side of the continuous film support in the transport direction from the temperature control roll.
Have,
The transport speed of the continuous film support on the temperature control roll is U, the viscosity of the air at the surface temperature of the temperature control roll is μ, the radius of the temperature control roll is R, the height of the knurling portion is h _k , and the temperature is high. When the tension applied to the continuous film on the adjusting roll is T and the distance from the separation point between the continuous film support and the temperature controlling roll to the contact point between the continuous film support and the roll member is L, the following relational expression A method for manufacturing an optical film that satisfies (1).

In the relational expression (1), the unit of L is m, the unit of U is m / min, the unit of μ is Pa · sec, the unit of h _k is m, and the unit of R is m. Yes, the unit of T is N / m. The method for manufacturing an optical film according to claim 1, wherein the transport speed U of the continuous film support on the temperature control roll is 5 m / min to 40 m / min. The method for producing an optical film according to claim 1 or 2, wherein the radius R of the temperature control roll is 0.2 m to 0.4 m. The method for producing an optical film according to any one of claims 1 to 3, wherein the surface temperature of the temperature control roll is 80 ° C to 160 ° C. The method for producing an optical film according to any one of claims 1 to 4, wherein the height h _k of the knurled portion of the continuous film support is 1 μm to 20 μm. The method for producing an optical film according to any one of claims 1 to 5, wherein the tension T applied to the continuous film on the temperature control roll is 100 N / m to 600 N / m. The method for producing an optical film according to any one of claims 1 to 6, wherein the thickness of the portion where the knurled portion of the continuous film support is not formed is 20 μm to 100 μm. The method for manufacturing an optical film according to any one of claims 1 to 7, wherein the width length of the continuous film support is 50 mm to 2000 mm. The method for manufacturing an optical film according to any one of claims 1 to 8, wherein the radius of the roll member is 20 mm to 70 mm.

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