KR102350418B1 - Manufacturing method of optical film - Google Patents

Abstract

The step of forming a coating film on the surface having the knurled portion of the continuous film support, and the surface opposite to the surface having the knurled portion of the continuous film support on which the coating film is formed is wound in contact with the temperature control roll, and the coating film on the temperature control roll is irradiated with active energy rays and a step of bringing the surface having the knurled portion of the continuous film support into contact with the roll member, the conveying speed U of the continuous film support, the viscosity μ of the air at the surface temperature of the temperature control roll, and the radius R of the temperature control roll And, the height h _{k of the} knurled portion, the tension T applied to the continuous film, and the distance L from the separation point of the temperature control roll of the continuous film support to the contact point of the roll member, the method for manufacturing an optical film satisfying the following relational expression (1) .

Description

Manufacturing method of optical film

The present disclosure relates to a method of manufacturing an optical film.

In recent years, the demand for optical films is increasing. As a typical example of an optical film, retardation film, an antireflection film, an anti-glare film, etc. are mentioned.

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 manufacturing an optical film, a coating film formation step of coating and drying an active energy ray-curable resin composition on the surface of a continuous film support to form a coating film, and irradiating active energy rays to the formed coating film to cure the coating film It has an energy-beam irradiation process and the method of forming the objective optical function layer in the surface of a continuous film support body is mentioned.

And, when manufacturing an optical film by a continuous process in a roll-to-roll method, since the continuous film support is in contact with various rolls, in order to prevent a shift in the conveying position of the continuous film support, knurled along both ends in the width direction It is preferable to use the continuous film support body which has the site|part in which the so-called micro-projection|protrusion was formed.

For example, in Japanese Patent Application Laid-Open No. 2017-032756, a first region formed by knurling on a base film and a second region formed by sandwiching the first region with a layer having a microrelief structure on its surface are provided. A transparent film having Moreover, as a manufacturing method of this transparent film, in the 2nd area|region, an active energy ray-curable resin composition is apply|coated on the base film in which the 1st area|region was formed, and an active energy ray-curable resin composition is pressed against the applied active energy ray-curable resin composition, and active energy A method of curing an active energy ray-curable resin composition by irradiating it with radiation and then separating a transfer mold is disclosed.

Moreover, in Unexamined-Japanese-Patent No. 2010-139824, a hard-coat layer coating composition is apply|coated on the elongate cellulose triacetate film to which the knurling process was given, and after drying, an ultraviolet lamp hardens an application layer. A method is disclosed.

When manufacturing an optical film, it is an active energy ray irradiation process WHEREIN: A dispersion|variation may generate|occur|produce in the irradiation amount of the active energy ray irradiated with respect to a coating film in the width direction of a continuous film support body. When there is variation in the amount of active energy ray irradiation in the width direction of the continuous film support, usually in the coating film forming step, in the width direction of the continuous film support, the application amount of the active energy ray cured resin composition is adjusted according to the variation in the amount of irradiation. are adjusting And the optical film manufactured by this adjustment WHEREIN: The nonuniformity of the optical characteristic in the width direction is suppressed.

However, in the active energy ray irradiation step, when the conveying position in the width direction of the continuous film support is shifted, the adjustment position of the application amount of the active energy ray cured resin composition performed in the coating film forming step shifts, and the optical film produced WHEREIN: The subject that it is difficult to suppress the nonuniformity of the optical characteristic in the width direction arises. The shift|offset|difference of the conveyance position of the width direction of a continuous film support body is reduced by using the continuous film support body which has a knurling part, for example.

On the other hand, active energy ray irradiation process WHEREIN: A continuous film support body is wound around a temperature control roll, and the means of irradiating an active energy ray with respect to the coating film on a temperature control roll may be taken. This means is capable of irradiating an active energy ray with respect to the coating film in a state extending along the shape of the temperature control roll, and at the point where the continuous film support is in contact with the temperature control roll, the temperature of the continuous film support is adjusted It is effective in terms of ease.

However, when using the continuous film support body which has a knurling part, if a knurling part is in contact with a temperature control roll, only the width direction end of a continuous film support body may float by presence of a knurling part. In the active energy ray irradiation step, if only the width direction end of the continuous film support floats, a difference occurs between the central portion and the end portion in the width direction in the amount of active energy ray irradiation, and the optical properties in the width direction in the optical film to be produced The subject that nonuniformity will generate|occur|produce arises.

In Unexamined-Japanese-Patent No. 2017-032756 and Unexamined-Japanese-Patent No. 2010-139824, in both, it is not specified whether the knurling part of a continuous film support body is in contact with a temperature control roll, but it is an active energy ray irradiation process WHEREIN: A continuous film support body It is not examined at all that a conveyance position shifts|deviates in the width direction of , or that only the width direction end of a continuous film support body floats. Therefore, in the technique of Unexamined-Japanese-Patent No. 2017-032756 and Unexamined-Japanese-Patent No. 2010-139824, it is thought that the nonuniformity of the optical characteristic in the width direction will generate|occur|produce in the above optical films manufactured.

Therefore, the problem to be solved by one embodiment of the present invention is made in view of the above circumstances, and using a continuous process in a roll-to-roll method, an optical film comprising a step of curing a coating film by irradiation with active energy rays It is to provide the manufacturing method of the optical film by which the nonuniformity of the optical characteristic in the width direction was reduced as a manufacturing method.

Means for solving the said subject include the following embodiment.

<1> a step of forming a coating film by coating and drying an active energy ray cured resin composition on a surface having a knurled portion of a continuous film support having knurled portions along both ends in the width direction, which is continuously conveyed;

A step of winding the surface opposite to the surface having the knurled portion of the continuous film support on which the coating film is formed in contact with a temperature control roll and irradiating an active energy ray to the coating film on the temperature control roll;

a step of bringing the surface having the knurled portion of the continuous film support into contact with a roll member provided on the downstream side in the conveyance direction of the continuous film support from the temperature control roll;

Let the conveying speed of the continuous film support on the temperature control roll be 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 part is h _k , and the temperature control roll An optical film that satisfies the following relational expression (1) when the tension applied to the continuous film manufacturing method.

[Equation 1]

In 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/m.

<2> The manufacturing method of the optical film as described in <1> whose conveyance speed U of the continuous film support on a temperature control roll is 5 m/min - 40 m/min.

<3> The method for producing the 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 manufacturing method of the optical film in any one of <1>-<3> whose surface temperature of a temperature control roll is 80 degreeC - 160 degreeC.

<5> The manufacturing method of the optical film in any one of <1>-<4> whose _{height h k} of the knurling part of a <5> continuous film support is 1 micrometer - 20 micrometers.

<6> The method for producing the 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.

The manufacturing method of the optical film in any one of <1>-<6> whose thickness of the location in which the knurling part of the <7> continuous film support body is not formed is 20 micrometers - 100 micrometers.

<8> The manufacturing method of the optical film in any one of <1>-<7> whose width length of a continuous film support body is 50 mm - 2000 mm.

The manufacturing method of the optical film in any one of <1>-<8> whose radius of a <9> roll member is 20 mm - 70 mm.

According to one embodiment of the present invention, in a method for manufacturing an optical film including a step of curing a coating film by irradiation of an active energy ray using a continuous process in a roll-to-roll system, the optical characteristic in the width direction is The manufacturing method of the optical film with which nonuniformity was reduced is provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic 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 body used for 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 body used for the manufacturing method of the optical film of one Embodiment.

Hereinafter, embodiment of the manufacturing method of an optical film is demonstrated. However, this invention is not limited at all to the following embodiment, In the range of the objective of this invention, it can add and implement a change suitably.

In the present disclosure, the numerical range indicated using “to” means a range including the numerical values before and after “to” as the minimum and maximum values, respectively.

In the numerical range described in steps in the present disclosure, the upper limit or lower limit described in a certain numerical range may be substituted with the upper limit or lower limit of the numerical range described in another stepwise manner. In addition, in the numerical range described in this indication, you may substitute the value shown in the Example for the upper limit or lower limit described in a certain numerical range.

Each element in each drawing shown in this disclosure is not necessarily to the exact scale, emphasis is placed on clearly showing the principle of the present disclosure, and there are places where emphasis is placed on.

In addition, in each figure, the same code|symbol is attached|subjected to the component which has the same function, and overlapping description is abbreviate|omitted.

In this indication, the "width direction" refers to the direction orthogonal to the longitudinal direction of a long continuous film support body and an optical film.

In this indication, the combination of two or more preferable aspects is a more preferable aspect.

≪Method for producing optical film≫

Although the present inventors examined the manufacturing method of the optical film including the process of hardening a coating film by irradiation of an active energy ray using the continuous process in a roll-to-roll system, by the following method, in the width direction found that the non-uniformity of the optical properties of

That is, in the manufacturing method of the optical film of one Embodiment, the active energy ray cured resin composition is apply|coated and dried to the surface which has a knurled part of the continuous film support body which has a knurling part along both ends of the width direction, which is continuously conveyed, and forms a coating film. Step (hereinafter, also referred to as “coating film forming step”), and the surface opposite to the side having the knurled portion of the continuous film support on which the coating film is formed is wound in contact with the temperature control roll, and the coating film on the temperature control roll is irradiated with active energy rays (hereinafter also referred to as "active energy ray irradiation process"), and a step of bringing the surface having the knurled portion of the continuous film support into contact with a roll member provided on the downstream side in the conveying direction of the continuous film support rather than the temperature control roll (hereinafter, " knurling part contact process"), the conveying speed of the continuous film support on the temperature control roll is U, the viscosity of air at the surface temperature of the temperature control roll is μ, the radius of the temperature control roll is R, When the height of the knurling part is h _k , the tension applied to the continuous film on the temperature-controlled roll is T, and the distance from the separation point between the continuous film support and the temperature-controlled roll to the contact point between the continuous film support and the roll member is L, It is a manufacturing method of an optical film which satisfy|fills relational expression (1) of.

[Equation 2]

In 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/m.

In the manufacturing method of said optical film, the continuous film support body which has a knurling part is used. And the continuous film support body is wound by making the surface opposite to the surface which has a knurling part contact a temperature control roll, and an active energy ray is irradiated with respect to the coating film on a temperature control roll in that area|region. By employing this method, in the active energy ray irradiation step, in the continuous film support on the temperature control roll, only the end in the width direction does not float. Therefore, it can suppress that a difference arises in the central part and the terminal of the width direction in the irradiation amount of an active energy ray resulting from this rise.

Moreover, in the manufacturing method of said optical film, in a knurling part contacting process, the continuous film support body makes the surface which has a knurling part contact the roll member provided on the downstream side in the conveyance direction of a continuous film support body rather than a temperature control roll. A knurling part contact process WHEREIN: It suppresses that a conveyance position shifts|deviates to the width direction of a continuous film support body by a knurling part contacting with respect to a roll member.

Here, by satisfying the relational expression (1), it is suppressed that the conveyance position shifts in the width direction of the continuous film support body also in the active energy ray irradiation step performed on the upstream side in the conveyance direction of the continuous film support from the knurled portion contacting step can do.

The detail of the said relational expression (1) is demonstrated.

In the relational formula (1), h _a is, in the active energy ray irradiation step, when the continuous film support is wound around the temperature-controlled roll, the continuous film support is generated because air is drawn between the continuous film support and the temperature-controlled roll, and It corresponds to the thickness of the air layer (so-called air film) between the temperature control rolls.

It means that the conveyance position shift of the continuous film support body on a temperature control roll becomes easy to occur, so that _{the thickness h a} of this air film is large.

In addition, h _k shows the height of the knurling part of a continuous film support body. If I becomes a knurled portion height h _k small relative to the thickness h _a of the air film, due to the contact of the board with the knurling roll member in the ring contact process, it is difficult to appear the inhibitory effect of the transfer position deviation. In other words, if I becomes a knurled portion height h _k small relative to the thickness h _a of the air film, difficult to grip the knurled portion of the roll member function, it is impossible to sufficiently suppress the transfer position deviation.

Thus, the correlation to the present inventors, noting the "divided by the thickness h _a knurled height h _k portion of the air film (i.e., the value of h _a / h _k)", generating the ease of the value and transfer the displacement I thought that there was, and research was conducted. As a result, _{when examining the relationship between "the value of h a} /h _k " and "the amount of displacement of the conveying position", the coefficient "2.38" and the multiplier "0.9" were obtained for "the value of _{h a} /h _k". In the case of application, since a correlation was obtained between 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, the relational expression (1) was found.

When the said relational expression (1) is satisfied, it is an active energy ray irradiation process. WHEREIN: It can suppress that a conveyance position shifts|deviates to the width direction of a continuous film support body.

Here, "U", "μ", and "T" in relational expression (1) will be described.

"U (unit: m/min)" in the relational expression (1) refers to the conveying speed of the continuous film support on the temperature control roll (that is, the continuous film support from the point of contact with the temperature control roll to the point apart from the temperature control roll).

“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 a literature value described in "Mechanics of a fluid (Corona published, published in 2002)" or a literature value.

"T (unit: N/m)" in relational expression (1) is the longitudinal direction (ie, conveying) with respect to the continuous film on the temperature control roll (that is, the continuous film support from the point of contact with the temperature control roll to the point apart from the temperature control roll) direction), that is, the tension applied to it.

As a result, according to the manufacturing method of the optical film of one Embodiment, the optical film by which the nonuniformity of the optical characteristic in the width direction was reduced can be manufactured.

Hereinafter, in the manufacturing method of the optical film of one Embodiment, the detail of a coating-film formation process, an active energy ray irradiation process, and a knurling part contact process is demonstrated.

Here, a cured film is formed on a continuous film support body by passing through a coating-film formation process and an active energy ray irradiation process. The cured film formed turns into an optical function layer (For example, an optically anisotropic layer, a reflection prevention layer, a glare-proof layer, etc.) in an optical film.

[coating film formation process]

In a coating film formation process, an active energy ray cured resin composition is apply|coated and dried to the surface which has a knurling part of the continuous film support body which has a knurling part along the both ends of the width direction continuously conveyed, and a coating film is formed.

An example of a coating-film formation process is demonstrated with reference to FIG.

As shown in FIG. 1, the wound continuous film support body 10, when the front-end|tip is sent out, first, on the surface opposite to the surface which has a knurling part, the active energy ray cured resin composition by the application|coating means 1 Application is carried out, and thereafter, it is dried in a drying area by means of drying means 2 . In this way, on the continuous film support body, the coating film obtained by apply|coating and drying an active energy ray cured resin composition is formed.

In the active energy ray irradiation process mentioned later, a continuous film support body makes the surface opposite to a knurling part contact with respect to a temperature control roll. Therefore, in this coating-film formation process, the surface to which an active energy ray cured resin composition is apply|coated turns into the surface which has a knurling part of a continuous film support body.

-Continuous Film Support-

A well-known polymer film can be used for the continuous film support body used for manufacture of an optical film.

Examples of the material of the polymer film used as the continuous film support include cellulose acylate (e.g., cellulose triacetate (triacetylcellulose, refractive index 1.48), cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate), Polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, acrylic resins such as polyethersulfone and polymethyl methacrylate, polyurethane, polycarbonate, polysulfone, polyether, Polymethylpentene, polyetherketone, poly(meth)acrylonitrile, polymer having an alicyclic structure (eg, norbornene-based resin (trade name "Aton (registered trademark)", JSR), amorphous polyolefin (eg For example, a brand name "Zeonex (trademark)", Nippon Zeon Corporation), etc. are mentioned.

Among these, from points, such as low optical anisotropy, triacetyl cellulose, polyethylene terephthalate (PET), and the polymer which has an alicyclic structure are preferable, and triacetyl cellulose is especially preferable.

As thickness of the location in which the knurling part of a continuous film support body is not formed, what is necessary is just to decide according to manufacturing aptitude, a use, etc., For example, the range of 3 micrometers - 250 micrometers is preferable. The thickness of the continuous film support is more preferably 20 µm or more from the viewpoint of high applicability to winding on a temperature control roll.

In particular, when the thickness of the continuous film support is small, shift in the conveying position tends to occur easily, but by satisfying the relational expression (1), a thin continuous film support in the range of 20 µm to 100 µm can be preferably used.

In addition, from the viewpoint of material cost, the thickness of the continuous film support is preferably 80 µm or less.

From said point, as thickness of a continuous film support body, 20 micrometers - 80 micrometers are preferable, and 20 micrometers - 60 micrometers are more preferable.

As width length of a continuous film support body, what is necessary is just to determine according to manufacturing aptitude, a use, etc., For example, the range of 50 mm - 2000 mm is preferable. Although the influence of the shift|offset|difference of a conveyance position is so large that width length is large, the continuous film support body of the width length of 800 mm - 1500 mm can be used preferably by satisfying relational expression (1).

A continuous film support body has a knurling part along the both ends of the width direction as shown to FIG. 2A.

Here, in the continuous film support body, a "knurling part" means the site|part (symbol 12 in FIG. 2A) in which the minute processus|protrusion as shown to FIG. 2B is provided.

The height of the knurled portion (that is, h _k in the relational formula (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 shift in the conveyance position of the continuous film support. more preferably.

The height of the knurled portion is, in the knurled portion of the continuous film support, 5000 mm from the longitudinal tip of the continuous film support (that is, each one of both ends in the width direction), and the end of the continuous film support in the longitudinal direction It points to the average value of the maximum height of a total of 4 places of 5000 mm from 2 places (that is, each one place of both ends in the width direction).

A specific measurement method is as follows.

First, at a position of 5000 mm from the front end of the continuous film support in the longitudinal direction, 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. By this measurement, the thickness of a continuous film support body can be measured from the location in which the knurling part is not formed to the area|region in which the knurling part is formed and thickness is large. Then, the largest value measured in the region where the knurling portion is formed and the thickness is large, that is, the value obtained by subtracting the average value of the thickness of the portion where the knurling portion is not formed from the thickness of the largest portion, is the maximum height do. This becomes the maximum height of the knurling part which a continuous film support body has in two places of 5000 mm from the front-end|tip of the longitudinal direction of a continuous film support body (that is, each one place of the both ends of the width direction).

Then, also in the position of 5000 mm from the terminal of the longitudinal direction of a continuous film support body, the measurement similar to the above is performed and the maximum height is calculated|required. This becomes the maximum height of the knurling part which a continuous film support body has at two places of 5000 mm from the end of the longitudinal direction of a continuous film support body (that is, each one place of the both ends of the width direction).

Here, for the measurement, a contact-type thickness gauge (Fuji Works, S-2270) is used. In addition, a thin piece of width 5mm including a position of 5000mm from the front-end|tip or end of the longitudinal direction of a continuous film support body is applied to a contact thickness measuring machine, and measurement is performed.

Here, the ratio of the sum of the widths of the knurled portions (w1 + w2 in Fig. 2A) is the function of preventing displacement of the conveying position, securing the effective width as a product, and improving the yield, the whole of the continuous film support With respect to width, the range of 0.5% - 5.0% is preferable, and the range of 0.7% - 4.0% is more preferable.

It is preferable that the distance from the edge part of the width direction of a continuous film support body to a knurling part is 0 mm - 15 mm.

Here, the distance from the edge part of the width direction of a continuous film support body to a knurling part refers to the distance (corresponding to distance d in FIG. 2A) from the edge part of the width direction of a continuous film support body to the outer edge of the width direction of a knurling part. . That is, it is preferable that a knurling part is provided in the position whose distance d from each edge part of the width direction of a continuous film support body is 0 mm - 15 mm, as shown to FIG. 2A. The distance d from the end of the continuous film support in the width direction to the knurled portion is easy to form the knurled portion, secures the effective width as a product, and improves the yield, in general, 0 mm to 20 mm is sufficient, 0 mm to 15 mm is preferable, and 2 mm - 15 mm are more preferable.

The protrusion in a knurling part is formed according to the shape of the convex part which a knurling roll has with respect to the continuous film support body at the time of formation of a knurling part. As a shape of a convex part, there exist a truncated pyramid, a truncated cone, and the like.

For example, if the shape of the convex part of the knurling roll is a quadrangular truncated pyramid (that is, a shape in which a quadrangular pyramid is cut in a plane parallel to the base and a pyramidal part having a vertex is removed), the convex part follows the shape of a quadrangle even on the continuous film support. (knurling) is formed.

The shape in which only the edge part of the shape of the convex part which a knurling roll has protrudes may be sufficient as the convex part formed in this continuous film support body.

The number of convex portions (knurling) formed on the continuous film support is determined from the point of expression of gripping force to the roll member, and from the viewpoint of securing the strength of the continuous film support in the region where the knurled portion is formed, the knurled portion in the continuous film support is as seen from the upper surface, 1cm ² 10 ~ 200 gae personal preferably sugar, more preferably 80-150 individuals per 1 cm ^2.

In addition, observation and the method of calculating|requiring the number of this convex part can be performed with the following method.

That is, since the convex parts are continuously arranged to form a knurled part, the number of this repeating minimum unit is made into the number of convex parts (it is also called "convex part density").

The number of convex portions (convex portion density) is, in the knurling portion of the continuous film support, two places at the tip in the longitudinal direction (that is, one each at both ends in the width direction) and two places at the end (i.e., in the width direction). Observe and count 5 mm squares with a 5x magnifying glass for a total of 4 places at both ends of each), and multiply the average value of each measuring point by 4 In addition, the obtained value rounds off 1st decimal place, and let this be the number of convex parts (convex part density).

In addition, the measurement location is 5000 mm from the front-end|tip in the longitudinal direction of the continuous film support body, and is 5000 mm from the end of the longitudinal direction of 2 places of 5 mm square including each of both outer ends of the knurling part in the width direction, and the continuous film support body. , let it be two places of 5 mm square including each of the both outer ends of the knurling part in the width direction.

In addition, when the width of the knurling part is less than 5 mm, the number of convex parts (convex part density) is counted by observing the maximum length four directions including both outer ends of the knurling part with a 5x magnifying glass, and converting this into the number per ^{1 cm 2 .} For example, if the width of the knurling part is 3 mm, the number of convex parts (density of convex parts) is counted by observing 3 mm in 4 places with a 5 times magnifying glass, and what is necessary is just to multiply the average value of each measurement location 100/9 times. In addition, the obtained value rounds off 1st decimal place, and let this be the number of convex parts (convex part density).

As shown in Fig. 2a, the knurled portion may be formed in one 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 if the sum of the widths of the knurled portion does not deviate from the above range, It may be formed in several strip|belts.

There is no restriction|limiting in particular in the formation method of a knurling part, A well-known knurling apparatus can be used.

As a knurling apparatus, the apparatus of Unexamined-Japanese-Patent No. 2014-218016 etc. can be used specifically,.

-apply-

A well-known application means is applied for application|coating.

As the application means, specifically, 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, wire bar The coating apparatus using the coating method etc. is mentioned.

-dry-

A well-known drying means is applied for drying.

Specific examples of the drying means include an oven, a hot air machine, an infrared (IR) heater, and the like.

In drying with a warm air machine, the continuous film support may have a configuration in which warm air is blown from the opposite side to the coated side of the continuous film support, and a diffuser plate is installed so that the surface of the applied coating solution does not flow with warm air. You can do it.

Drying conditions should just be determined according to the kind of coating liquid used, application amount, conveyance speed, etc., For example, it is 30 degreeC - 140 degreeC, and it is preferable to carry out for 10 seconds - 10 minutes.

A non-hardened coating film hardened|cured by an active energy ray through the above coating-film formation process is formed.

What is necessary is just to determine the thickness of the coating film obtained through a coating-film formation process according to the use of an optical film. If the coating film is a coating film for a liquid crystal layer described later, the film thickness (so-called dry film thickness) of the coating film after drying provided in the active energy ray irradiation step (so-called dry film thickness) is preferably 0.5 μm to 10 μm, more preferably 1 μm to 5 μm.

In addition, 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 application (so-called wet film thickness) is preferably 3 µm to 30 µm, and more preferably 5 µm to 15 µm.

[Active energy ray irradiation process]

In an active energy ray irradiation process, the surface opposite to the surface which has a knurling part of the continuous film support body with a coating film is made to contact a temperature control roll, and is wound, and an active energy ray is irradiated with respect to the coating film on a temperature control roll.

An example of an active energy ray irradiation process is demonstrated with reference to FIG.

As shown in Fig. 1, the continuous film support 10 on which the coating film was formed is wound around a temperature control roll 34, and in this region, the coating film on the temperature control roll 34 is irradiated with an active energy ray from the exposure light source 32. .

At this time, the surface opposite to the knurling part of the continuous film support body 10 is contacting with the temperature control roll 34. As shown in FIG. Therefore, the width direction edge part of the continuous film support body 10 is lifted up by the knurling part with respect to the temperature control roll 34, and it does not float up.

Here, in FIG. 1, P represents the contact point of the continuous film support body 10 and the temperature control roll 34, and Q represents the separation point of the continuous film support body 10 and the temperature control roll 34. In FIG. That is, the continuous film support body 10 will be in contact with the temperature control roll 34 from the contact point P to the separation point Q.

-Active energy rays-

There will be no restriction|limiting in particular as an active energy ray used in an active energy ray irradiation process, if the energy which can generate|occur|produce active species in the coating film to irradiate can be provided. Specific examples of active energy rays include α-rays, γ-rays, X-rays, ultraviolet rays, infrared rays, visible rays, and electron beams. Among these, as an active energy ray used in an active energy ray irradiation process from a viewpoint of hardening sensitivity and the availability of an apparatus, an ultraviolet-ray or an electron beam is preferable and an ultraviolet-ray is more preferable.

-Exposure light source-

In an active energy ray irradiation process, as an exposure light source used in order to irradiate an active energy ray, the light source which irradiates the above-mentioned active energy ray is mentioned. From the viewpoint of curing sensitivity and availability of an apparatus, as an exposure light source, a light source irradiating an ultraviolet ray is preferable.

Examples of the light source for irradiating ultraviolet light include lamps such as tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps, mercury xenon lamps, carbon arc lamps, and various lasers (eg, semiconductor lasers, helium neon lasers, Argon ion laser, helium cadmium laser, YAG (Yttrium Aluminum Garnet) laser), a light emitting diode, a cathode ray tube, etc. are mentioned.

As for the peak wavelength of the ultraviolet-ray emitted from the light source which irradiates an ultraviolet-ray, 200 nm - 400 nm are preferable.

-Temperature Roll-

There is no restriction|limiting in particular as for the temperature control roll used in an active energy ray irradiation process, A well-known thing can be used.

As a temperature control roll, the thing by which the hard chromium plating was carried out on the surface can be used preferably, for example.

As for the thickness of plating, 40 micrometers - 60 micrometers are preferable from a viewpoint of ensuring electroconductivity and strength.

Moreover, as for the surface roughness of a temperature control roll, 0.1 micrometer or less is preferable in surface roughness Ra from a point which reduces the nonuniformity of the frictional force between a continuous film support body and a temperature control roll.

The surface temperature of the temperature control roll may be determined according to the composition of the coating film, curing performance of the coating film, heat resistance of the continuous film support, etc., preferably 60°C to 250°C, more preferably 80°C to 160°C, 80°C to 140°C C is more preferred.

By making the surface temperature of a temperature control roll into said temperature, the curing rate of a coating film can be raised and the temperature control of the continuous film support body to be wound can also be performed. Moreover, the viscosity of the air in relational formula (1) changes with the surface temperature of a 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 five arbitrary points in the width direction of the temperature control roll. Let the average value of the measured values be the surface temperature of the temperature control roll.

It is preferable that the surface temperature of a temperature control roll is detected, and the surface temperature of the temperature control roll is maintained by a 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, etc. are used, and as the cooling means, cooling by cooling water is used.

The radius of the temperature control roll (that is, R in the relational formula (1)) is preferably 0.1 m to 0.5 m from the viewpoint of easy winding of the continuous film support, easy irradiation with active energy rays, and manufacturing cost of the temperature control roll. And 0.2m - 0.4m are more preferable.

In the active energy ray irradiation step, since it is carried out with respect to the continuous film support in a state in which irradiation with active energy rays is applied, the tension (also referred to as tension) in the longitudinal direction (that is, in the conveying direction) with respect to the continuous film support on which the temperature control roll is wound. is hanging

The tension (ie, T in relational formula (1)) applied to the continuous film support on the temperature control roll is preferably 100 N/m to 700 N/m, more preferably 100 N/m to 650 N/m, and 300 N/m to 600 N/m is more preferable, and 400 N/m - 600 N/m are especially preferable.

Since the tension|tensile_strength (that is, tension|tensile_strength) applied to the longitudinal direction of the continuous film support body on a temperature control roll cannot directly measure, the value measured as follows is employ|adopted.

That is, the length of the continuous film support on the temperature control roll by the tension sensor provided on the downstream side in the conveying direction of the continuous film support (for example, a position 5000 mm away from the separation point between the continuous film support and the temperature roll) with respect to the temperature control roll Measure the tension in the direction. Here, as the tension sensor, for example, a tension sensor having a built-in load cell is suitable, and specifically, an MB tension sensor manufactured by Nireco Corporation is exemplified.

The conveying speed of the continuous film support on the temperature control roll (that is, U in the relational formula (1)) is 5 m/min or more and 40 m/min or less from the viewpoint of securing productivity and increasing the accuracy of irradiation with active energy rays. It is preferable that they are 10 m/min or more and 30 m/min or less, It is more preferable that they are 15 m/min or more and 25 m/min or less.

Moreover, since the conveyance speed of the continuous film support on the temperature control roll coincides with the rotation speed (so-called circumferential speed) of the temperature control roll, what is necessary is just to employ|adopt the value of the rotation speed of the temperature control roll.

Moreover, 60 degrees or more are preferable and, as for the wrap angle of the continuous film support body with respect to a temperature control roll, 90 degrees or more are more preferable.

The upper limit of the lap angle is, for example, 180°.

In addition, the wrap angle means the angle which consists of the conveyance direction of the continuous film support body when a continuous film support body contacts with a temperature control roll, and the conveyance direction of a continuous film support body when the continuous film support body separates from a temperature control roll.

Through the above active energy ray irradiation process, a coating film is hardened|cured and a cured film (namely, optical function layer) is formed on a continuous film support body.

[Knurling part contact process]

In a knurling part contact process, the surface which has a knurling part of a continuous film support body is made to contact the roll member provided in the conveyance direction downstream of a continuous film support body rather than a temperature control roll.

An example of a knurling part contacting process is demonstrated with reference to FIG.

As shown in FIG. 1, the continuous film support body 10 with a coating film is wound around the roll member 4, after separating from the temperature control roll 34. As shown in FIG.

At this time, the knurled part of the continuous film support body 10 is in contact with the roll member 4, the grip performance to the roll member 4 by the knurling part is expressed, and the shift|offset|difference of the conveyance position of the continuous film support body 10 is corrected. restrain

Here, in FIG. 1, S represents the contact point of the continuous film support body 10 and the roll member 4. FIG. 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.

-No roll-

The roll member should just be provided in the position which satisfy|fills 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 may be provided so as to be less than _{2.38×(h a} /h _k ) ^{0.9 in the relational formula (1).}

By providing a roll member in the above positions, it is the active energy ray irradiation process demonstrated above. WHEREIN: It can suppress that a conveyance position shifts|deviates to the width direction of a continuous film support body.

There is no restriction|limiting in particular as a roll member, A well-known conveyance roll can be used.

There is no restriction|limiting in particular as a material of a roll member, What was plated on the surface may be sufficient.

As a roll member, for suppression of the shift|offset|difference of the conveyance position by a knurling part, 0.4 micrometer - 1.6 micrometers are preferable in surface roughness, for example, maximum height Rz, for example.

As a radius of a roll member, 10 mm - 100 mm are preferable and 20 mm - 70 mm are more preferable from points, such as the point which a continuous film support body is easy to wind, and expression of the grip force by a knurling part.

60 degrees or more are preferable at the point which it is easy to suppress the shift|offset|difference of the conveyance position of the width direction of a continuous film support body, and, as for the wrap angle of the continuous film support body with respect to a roll member, 90 degrees or more are more preferable.

The upper limit of the lap angle is, for example, 180°.

After the above knurling part contact process, the continuous film support body in which the cured film (namely, optical function layer) was formed is wound up in roll shape, as shown, for example in FIG.

As an optical function layer formed by the manufacturing method of the optical film of one Embodiment, the optically anisotropic layer in retardation film, the reflection prevention layer in an antireflection film, the glare-proof layer in an anti-glare film, etc. are mentioned.

That is, according to the manufacturing method of the optical film of one Embodiment, the retardation film which has an optically anisotropic layer, the antireflection film which has an antireflection layer, the antiglare film which has an antiglare layer, etc. are mentioned.

[Method for producing retardation film]

Hereinafter, as an example of the manufacturing method of the optical film of one Embodiment, the manufacturing method of retardation film is demonstrated.

The retardation film is, on a continuous film support, an alignment layer having an orientation regulating force in order to align the liquid crystal compound of the liquid crystal layer in a certain direction, and an optically anisotropic layer (hereinafter also referred to as a liquid crystal layer) comprising a liquid crystal compound oriented and immobilized ) are provided in this order.

(Orientation layer and its formation method)

There is no restriction|limiting in particular as long as the orientation regulating force is provided for the orientation layer in retardation film in order to line up the liquid crystal compound of a liquid crystal layer in a fixed direction.

The alignment layer in the retardation film is, for example, an alignment layer to which an alignment regulating force with respect to a liquid crystal compound is imparted by a rubbing method, specifically, a layer of an organic compound (preferably a polymer) subjected to a rubbing treatment. .

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) in a certain direction with a rubbing cloth, thereby imparting an alignment regulating force to the liquid crystal compound to the coating film. Moreover, the process of rubbing the surface of the coating film for alignment layers in a fixed direction with a rubbing cloth is called a rubbing process.

-Material for forming alignment layer-

It is preferable that the solvent which melt|dissolves the organic compound and organic compound shown below as a material for orientation layer formation used for formation of an orientation layer is preferable.

Examples of the organic compound include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/maleimide copolymer, polyvinyl alcohol, poly(N-methylolacrylamide), styrene/vinyltoluene. copolymers, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, carboxymethylcellulose, polyethylene, polypropylene, and Polymers, such as polycarbonate, and compounds, such as a silane coupling agent, are mentioned.

Preferred examples of the polymer include polyimide, polystyrene, a styrene derivative polymer, polyvinyl alcohol, and alkyl-modified polyvinyl alcohol having an alkyl group (preferably an alkyl group having 6 or more carbon atoms).

The polymer used for the material for forming the alignment layer is particularly preferably alkyl-modified polyvinyl alcohol, and an alkyl group having 6 to 14 carbon atoms is -S-, -(CH ₃ )C(CN)-, or -(C ₂ H ₅ ) Alkyl-modified polyvinyl alcohol bonded to the terminal or side chain of polyvinyl alcohol through N-CS-S- is preferable.

As for the coating film for orientation layers, the method similar to the application|coating method and drying method in the coating-film formation process demonstrated above can be used, and a preferable aspect is also the same.

0.1 micrometer - 5 micrometers are preferable and, as for the film thickness of the coating film for alignment layers, 0.2 micrometer - 1 micrometer are more preferable.

-Grant of orientation regulation-

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 certain direction with a rubbing cloth.

There is no restriction|limiting in particular as a rubbing process, A well-known method is applicable. Specific examples of the rubbing treatment include a method of rubbing the surface of the coating film for the alignment layer in a certain direction with a rubbing cloth such as paper, gauze, felt, rubber, nylon, or polyester fiber. In general, a rubbing treatment of rubbing the surface of the coating film for an orientation layer about several times is performed using a rubbing cloth in which fibers of uniform length and thickness are implanted on average.

As mentioned above, the orientation layer provided with the orientation regulating force with respect to a 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. Then, orientation and fixation of the liquid crystal compound in the coating film for liquid crystal layers are made, and a liquid crystal layer (namely, optically anisotropic layer) can be obtained.

When the manufacturing method of the optical film of one embodiment is the manufacturing method of the retardation film, the formation of the coating film for a liquid crystal layer corresponds to the coating film formation process described above, and the material for forming a liquid crystal layer used to form the coating film for a liquid crystal layer is active It corresponds to an energy-beam curable resin composition.

-Material for forming liquid crystal layer-

The material for forming a liquid crystal layer contains a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound, and is a material that is cured with an electron energy ray. In addition to the rod-shaped liquid crystal compound or disk-shaped liquid crystal compound, the material for forming the liquid crystal layer contains, if necessary, other known components such as a polymerizable compound, a crosslinkable compound, a chiral agent, an orientation control agent, a polymerization initiator, and an orientation aid. may contain.

· Rod-shaped liquid crystal compound

Examples of the rod-like liquid crystal compound include azomethines, azoxyls, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, and cyano-substituted phenylpyrimidines. , alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolans, and alkenylcyclohexylbenzonitriles are preferably used.

Not only the low-molecular liquid crystalline molecules described above, but also high-molecular liquid crystalline molecules can be used.

As for the rod-shaped liquid crystal compound, it is more preferable to fix the orientation by superposition|polymerization, Therefore, it is preferable to use the rod-shaped liquid crystal compound which has a polymeric group.

As a rod-shaped liquid crystal compound which has polymerizability, Makromol. Chem., Vol. 190, p. 2255 (1989), Advanced Materials Vol. 5, p. 107 (1993), U.S. Patent Publication Nos. 4683327, 5622648, 5770107, International Publication No. 95/022586, the same 95/024455, 97/000600, 98/023580, 98/052905, Japanese Patent Laid-Open Nos. 1-272551, 6-016616, 7-110469, 11 -080081 and the compound of Unexamined-Japanese-Patent No. 2001-328973, etc. are mentioned.

Moreover, as a rod-shaped liquid crystal compound, the thing of Unexamined-Japanese-Patent No. 11-513019, Unexamined-Japanese-Patent No. 2007-279688, etc. can be used preferably, for example.

Discoid liquid crystal compound

As a discotic liquid crystal compound, the thing of Unexamined-Japanese-Patent No. 2007-108732, Unexamined-Japanese-Patent No. 2010-244038, etc. can be used preferably, for example.

As for the coating film for liquid crystal layers, the method similar to the application|coating method and drying method in the coating-film formation process demonstrated above can be used, and a preferable aspect is also the same.

-Orientation of liquid crystal compound-

Before fixing the orientation of the liquid crystal compound in the coating film for liquid crystal layers, it is preferable to perform the orientation process of the liquid crystal compound in the coating film for liquid crystal layers.

The orientation 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 in the alignment treatment can generally be transferred by a change in temperature or pressure. Moreover, in the case of the liquid crystal compound which has a lyotropic property, it can be made to transfer also with composition ratio, such as an amount of solvent.

When the rod-shaped liquid crystal compound expresses a 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, by heating the rod-shaped liquid crystal compound to a temperature range where the rod-shaped liquid crystal compound expresses a nematic phase, and then lowering the heating temperature to a temperature range where the rod-shaped liquid crystal compound expresses a smectic phase, the rod-shaped liquid crystal compound is removed from the nematic phase It can metastasize to tics. By setting it as a smectic phase by such a method, the liquid crystal in which the liquid crystal compound was oriented with high order can be obtained.

In the temperature range where the rod-shaped liquid crystal compound exhibits a 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 from 10 seconds to 5 minutes, more preferably from 10 seconds to 3 minutes, and most preferably from 10 seconds to 2 minutes.

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

The orientation of a liquid crystal compound may be performed by drying at the time of forming the coating film for liquid crystal layers. That is, by drying at the time of forming the coating film for liquid crystal layers, you may perform both drying of the material for liquid crystal layer formation apply|coated on the orientation layer, and the orientation of a liquid crystal compound.

Of course, you may perform the orientation of a liquid crystal compound separately from drying at the time of forming the coating film for liquid crystal layers.

-Fixation of orientation of liquid crystal compound-

It is preferable to perform the fixation of the orientation of the liquid crystal compound in the coating film for liquid-crystal layers by hardening the coating film for liquid-crystal layers by thermal polymerization or polymerization by an active energy ray.

When the manufacturing method of the optical film of one Embodiment is the manufacturing method of retardation film, fixation of the orientation of the liquid crystal compound using an active energy ray corresponds to the active energy ray irradiation process demonstrated above.

In the case of using a liquid crystal compound having polymerizability, when the amount of active energy ray irradiation is small, an unpolymerized liquid crystal compound remains and causes temperature change of optical properties, 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.

As irradiation conditions, although it also changes with the prescription of the material for liquid-crystal layer formation, and the thickness of the coating film for liquid-crystal layers, 50 mJ/cm ² -1000 mJ/cm ² are preferable, as for the amount of active energy ray irradiation, 100 mJ/cm ² -500 mJ/cm ² is more preferable.

As a light source used for irradiation of an active energy ray, the exposure light source in the coating-film formation process demonstrated above is applicable, and a preferable aspect is also the same.

In addition, description of Unexamined-Japanese-Patent No. 2008-225281 and Unexamined-Japanese-Patent No. 2008-026730 can be considered into the detail of a liquid crystal layer.

The retardation film obtained as mentioned above has few nonuniformity of the optical characteristic (for example, retardation) in the width direction.

Therefore, it can become a retardation film excellent in the in-plane uniformity of an optical characteristic (for example, retardation).

As mentioned above, when obtaining the liquid crystal layer of retardation film, although the example of applying the manufacturing method of the optical film of one Embodiment was demonstrated, in addition, the antireflection layer of the antireflection film, the antiglare layer of an antiglare film, etc. which were demonstrated previously were obtained It can also be applied when

Example

Hereinafter, the present invention will be more specifically described by way of Examples. Materials, usage amounts, ratios, treatment details, treatment procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Continuous film support having knurled part>

[Continuous film support (1) to (3)]

A continuous film support (cellulose triacetate film TJ40, Fujifilm) with knurled portions described in Table 1 was prepared.

The width and length of the prepared continuous film support was 1.34 m, and the length was 1000 m.

In Table 1, "the number of bands" means the number of bands by knurled portions 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, and "convex" ^{The "buffer density" means the number of convex portions present per 1 cm 2} of the knurled portion in the continuous film support when viewed from the top, and the "thickness of the support" is the thickness of the location where the knurled portion of the continuous film support is not formed. indicates

[Table 1]

[Measurement of knurled part]

With respect to 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.

A measurement result is shown in Table 1.

[Example 1]

(Formation of coating film for alignment layer and rubbing treatment)

Length 1000 m, width 1340 mm, 2 mass % aqueous solution of alkyl-modified polyvinyl alcohol (Poval MP-203, Kurares Corporation) on one side (surface having knurled portion) of the continuous film support 1 per ^{1 m 2 of the continuous film support} After 25 ml of application, the coating film for an orientation layer with a dry film thickness of 0.5 µm was formed by drying at 60°C for 60 seconds. And conveying the continuous film support body with the coating film for orientation layers at a conveyance speed of 30 m/min, the surface of the coating film for orientation layers was rubbed, and the orientation layer with a thickness of 0.5 micrometer was formed.

(Formation of coating film for liquid crystal layer: coating film formation process)

Then, with the apparatus comprised as shown in FIG. 1, the coating-film formation process, the active energy ray irradiation process, and the knurling part contact process were performed.

Specifically, the material for forming a liquid crystal layer prepared with the following composition was applied onto the alignment layer using a bar coater.

The continuous film support to which the material for forming a liquid crystal layer was applied was heated to a film surface temperature of 150° C. for 60 seconds and dried to form a coating film for a liquid crystal layer having a dry film thickness of 2 μm.

-Composition of material for forming liquid crystal layer-

The following reverse wavelength dispersion liquid crystalline compound R-2: 100 mass parts

Photoinitiator: 3.0 mass parts

(Irgacure 819, BASF)

The following fluorine-containing compound A: 0.8 parts by mass

The following crosslinkable polymer O-2 (Tg: 10 degreeC): 0.3 mass part

Chloroform: 588 parts by mass

[Formula 1]

[Formula 2]

[Formula 3]

(Irradiation of ultraviolet rays: active energy ray irradiation process)

Then, to a temperature control roll having a surface temperature of 120°C (radius R: 0.3 m, material stainless steel), the continuous film support on which a coating film for a liquid crystal layer is formed is brought into contact with the surface opposite to the surface having a knurled portion on the temperature control roll, and the lap angle is 90° wrapped with 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 to obtain a liquid crystal layer. The irradiation amount of ultraviolet rays was 300 mJ/cm ² .

Here, the conveying speed U of the continuous film support with a coating film for a liquid crystal layer on the temperature control roll was 20 m/min, and the tension T applied in the longitudinal direction of the continuous film support with a coating film on the temperature control roll was 450 N/m.

Here, the viscosity μ of the air at a surface temperature of 120° C. of the temperature control roll was 2.299×10 ⁻⁵ Pa·sec.

(Knurled part contact process)

After the active energy ray irradiation process, the continuous film support on which the liquid crystal layer was formed was transferred to the roll member (radius 50 mm, material stainless steel), and the knurled part on the same side as the liquid crystal layer was contacted with a roll member, and wound at a wrap 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 was put together in Table 2.

[Examples 2-7, and Comparative Examples 1-8]

Example 1, except that the continuous film support (1) was changed to any one of the continuous film supports (2) to (3) shown in Table 2, and/or the value of each condition was changed to the value shown in Table 2 below In the same manner, retardation film was produced.

[Evaluation: Evaluation of Non-uniformity of Optical Properties]

About the retardation film produced by the said Example and the comparative example, the nonuniformity of the optical characteristic in the width direction was evaluated based on the following method and evaluation criteria. A result is shown in Table 2.

From the end of the obtained retardation film (that is, the end on the winding end side) in the longitudinal direction, at 3 points of 1 m, 500 m, and 999 m, 13 points in the width direction (specifically, 6 at 100 mm intervals from one end in the width direction) Retardation was measured with respect to the point, 1 point|piece with 50 mm space|interval, and 1 point with a 50-mm space|interval, and 13 points|pieces of 5 points|pieces successively, with 100 mm space|interval).

The difference between the maximum value and the minimum value was calculated|required from the measured value of the retardation of 13 points|pieces of the width direction, and the thing which this difference is the largest among said three places was made into evaluation object. The greater the difference, the greater the non-uniformity of the optical properties in the width direction.

An automatic birefringence meter (KOBRA-21ADH, Oji Keisoku Kiki Co., Ltd.) was used for the measurement of retardation.

[Table 2]

As is clear from Table 2, the retardation film of an Example turns out that the nonuniformity of the optical characteristic in the width direction is suppressed compared with the retardation film of a comparative example.

As for the indication of the Japanese application 2018-062709 for which it applied on March 28, 2018, the whole is taken in into this specification by reference.

All documents, patent applications, and technical standards described in this specification are incorporated by reference in this specification to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually indicated to be incorporated by reference. do.

1 means of application
2 means of drying
10 continuous film support
12 knurled part
32 exposure light source
34 temperature roll
4 Roll member
d distance from each end in the width direction of the continuous film support of the knurled part
w1 Width of knurled part
w2 width of knurled part
P Contact point of continuous film support and temperature roll
Q Difference between continuous film support and temperature roll
Contact point of S continuous film support and roll member

Claims (9)

A step of forming a coating film by coating and drying an active energy ray-curable resin composition on a surface having knurled portions of a continuous film support having knurled portions along both ends in the width direction, which is continuously conveyed;
A step of winding the surface of the continuous film support on which the coating film is formed, 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;
a step of bringing the surface having the knurled portion of the continuous film support into contact with a roll member provided on the downstream side in the conveyance direction of the continuous film support from the temperature control roll;
Let the conveying speed of the continuous film support on the temperature control roll be 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 part is h _k , and the temperature control roll An optical film that satisfies the following relational expression (1) when the tension applied to the continuous film manufacturing method.
[Equation 1]

In 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/m. The method according to claim 1,
The manufacturing method of the optical film whose conveyance speed U of the continuous film support on a temperature control roll is 5 m/min - 40 m/min. The method according to claim 1 or 2,
The manufacturing method of the optical film whose radius R of a temperature control roll is 0.2m - 0.4m. The method according to claim 1 or 2,
The manufacturing method of the optical film whose surface temperature of a temperature control roll is 80 degreeC - 160 degreeC. The method according to claim 1 or 2,
The manufacturing method of the optical film whose _{height h k} of the knurling part of a continuous film support is 1 micrometer - 20 micrometers. The method according to claim 1 or 2,
A method for producing an optical film, wherein the tension T applied to the continuous film on the temperature control roll is 100 N/m to 600 N/m. The method according to claim 1 or 2,
The manufacturing method of the optical film whose thickness of the location in which the knurling part of the continuous film support body is not formed is 20 micrometers - 100 micrometers. The method according to claim 1 or 2,
The manufacturing method of the optical film whose width length of a continuous film support is 50 mm - 2000 mm. The method according to claim 1 or 2,
The manufacturing method of the optical film whose radius of a roll member is 20 mm - 70 mm.

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