KR102221032B1 - Optical multilayer body, flexible display device and method for producing optical multilayer body - Google Patents

Abstract

를 충족시키는, 광학 적층체.[Problem] An optical laminate excellent in optical homogeneity, a flexible display device including the optical laminate, and a method for producing the optical laminate are provided.
[Solution means] An optical laminate comprising an optical film comprising a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one side of the optical film,
The line profiles in directions h and v that are orthogonal to each other in the film inverse space obtained by Fourier transform of the projection image obtained by projection using the optical film or optical laminate are referred to as line profile h and line profile v, respectively. In the projection method, a background image obtained without using the film or an optical layered body is Fourier transformed, and the line profiles in the directions h'and v'perpendicular to each other in the background inverse space obtained are each line profile h 'And line profile v', and the maximum intensity of the line profile (h-h') obtained by subtracting the line profile h'from the line profile h is _{called Y mh} , and the frequency representing the _{maximum intensity Y mh} is called _{X mh,} If the maximum intensity of the line profile (v-v') obtained by subtracting the line profile v'from the line profile v is _{called Y mv} , and the frequency representing the _{maximum intensity Y mv is called X mv} , then _{both Y mh} and Y _mv are 40 or less. Where Y _mh , Y _mv , X _mh and X _mv are in the following relationship:

To meet the optical laminate.

Description

An optical laminated body, a flexible display device, and a manufacturing method of an optical laminated body TECHNICAL FIELD [OPTICAL MULTILAYER BODY, FLEXIBLE DISPLAY DEVICE AND METHOD FOR PRODUCING OPTICAL MULTILAYER BODY}

The present invention relates to an optical laminate, a flexible display device including the optical laminate, and a method of manufacturing the optical laminate.

An optical film used in an image display device such as a liquid crystal display device or an organic EL display device is required to have very high optical homogeneity because a user directly visually recognizes an image displayed with the naked eye through the optical film.

As a manufacturing method of such an optical film, a method of applying a solution containing a volatile solvent and a resin constituting the optical film on a substrate, drying, and then peeling is used (for example, Patent Document 1). In the manufacturing method accompanying such coating and drying, thickness unevenness and orientation unevenness may occur depending on coating conditions and drying conditions. Even if the film has a level of non-uniformity that is unlikely to be visible with the naked eye, when finally assembled as an optical film in an image display device, optical homogeneity is impaired due to such non-uniformity, resulting in image distortion, etc. Sometimes it is admitted. For this reason, a film used as an optical film in an image display device is required to have extremely high precision optical homogeneity at a level that is difficult to check with the naked eye. Because of this, there is also a need for further improvement of the optical homogeneity of the film.

As an optical film in which non-uniformity of the film is suppressed, for example, in Patent Document 1, in a rectangular area cut out from a projection image of a polyimide optical film, the standard deviation σ of gray scale and the blackness in the binarized image of the rectangular area A polyimide-based optical film in which the area of the portion is adjusted within a predetermined range is described. Patent Document 2 describes a transparent film for optics in which the non-uniformity in the luminance of transmitted light in the film plane is within 15% of the average luminance in terms of standard deviation. In Patent Document 3, light from a light source is irradiated onto a grating plate, the light transmitted through the grating plate is projected as a grating, and the grating image is photographed to quantify the three-dimensional shape of the object to be measured from the distortion of the grating. A method of measuring a shape by a fringe projection method is described.

International Publication No. 2016/152459 Japanese Unexamined Patent Application Publication No. Hei 9-48866 Japanese Unexamined Patent Application Publication No. 2011-226871

However, none of the methods described in the above patent documents are sufficient methods for evaluating the optical homogeneity of the film with very high precision required for an optical film as used in an image display device. Since the method described in Patent Document 1 is an evaluation in an analysis area of 1 cm x 5 cm, it is not a method capable of sufficiently evaluating the decrease in optical homogeneity caused by non-uniformity occurring in the longitudinal direction. The method described in Patent Literature 2 is not a method capable of accurately evaluating the decrease in optical homogeneity caused by non-uniformity in which the difference in luminance of transmitted light is small.

Since the method described in Patent Literature 3 is a method of detecting a shape, it is not possible to evaluate the decrease in optical homogeneity due to non-uniformity in the refractive index. Therefore, it cannot be said that all films obtained by evaluating by these methods have sufficient optical homogeneity.

The present invention has been made in view of the problems of the prior art, and is suitably used as an optical film in an image display device and the like, an optical laminate excellent in optical homogeneity, a flexible display device including the optical laminate, and It is a subject to provide the manufacturing method of the said optical laminated body.

In order to solve the above problems, the inventors of the present invention earnestly examine an evaluation method capable of evaluating the optical homogeneity of an optical film or optical laminate with high precision, and a method of increasing the optical homogeneity and optical properties of the optical film or optical laminate. Did. As a result, it was found that an optical laminated body that satisfies the following requirements has excellent optical homogeneity, and the present invention was completed. That is, the following aspects are included in this invention.

[1] An optical laminate having an optical film containing a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one surface of the optical film,

The line profiles in directions h and v perpendicular to each other in the film inverse space obtained by Fourier transform of the projection image obtained by the projection method using the optical film are referred to as line profile h and line profile v, respectively, and the projection method In the background inverse space obtained by Fourier transform of the background image obtained without using the film, the line profiles in the directions h'and v'perpendicular to each other are referred to as line profile h'and line profile v', respectively. , a line is called the maximum strength of the profile h line profile h 'line profile (h-h obtained by subtracting') from the said Y _mh, the frequency showing the maximum intensity Y _mh X _mh, line profile v line profile v from ' If the maximum intensity of the line profile (v-v') obtained by subtracting is Y _mv , and the frequency representing the _{maximum intensity Y mv is X mv} , _{both Y mh} and Y _mv are 40 or less, and Y _mh , Y _mv , X _mh and X _mv have the following relationship:

To meet the optical laminate.

[2] An optical laminate comprising an optical film containing a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one side of the optical film,

The line profiles in directions h and v that are orthogonal to each other in the film inverse space obtained by Fourier transform of the projection image obtained by the projection method using the optical laminate are referred to as line profile h and line profile v, respectively, In the projection method, the line profiles in the directions h'and v'that are orthogonal to each other in the background inverse space obtained by Fourier transform of the background image obtained without the use of the optical layered body are defined as the line profile h'and the line profile v. The maximum strength of the line profile (h-h') obtained by subtracting the line profile h'from the line profile h is _{called Y mh} , and the frequency representing the _{maximum strength Y mh is called X mh} , and the line profile v If the maximum intensity of the line profile (v-v') obtained by subtracting the profile _v'is called Y mv, and the frequency representing the _{maximum intensity Y mv} is called _{X mv , both Y mh} and Y _mv are 40 or less, and Y _mh , Y _mv , X _mh and X _mv have the following relationship:

To meet the optical laminate.

(3) At least one of the functional layers is a layer having at least one function selected from the group consisting of a hard coating function, an antistatic function, an antiglare function, a low reflection function, an antireflection function, and an antifouling function, The optical laminate according to [1] or [2] above.

[4] The optical laminate according to any one of [1] to [3], wherein the pencil hardness of at least one surface of the optical laminate is H or more.

[5] The optical laminate according to any one of [1] to [4], wherein the surface resistivity of at least one surface of the optical laminate is 1.0×10 ^{13 Ω/sq or less.}

[6] The optical laminate according to any of [1] to [5], wherein the optical laminate has a yellowness of 3.0 or less.

[7] The optical laminate according to any one of [1] to [6], wherein the length in the width direction is 20 cm or more and the length in the length direction is 1 m or more.

[8] The optical laminate according to any one of [1] to [7], which is a film for a front plate of a flexible display device.

[9] A flexible display device comprising the optical laminate according to any one of [1] to [8].

[10] The flexible display device according to [9], further comprising a touch sensor.

[11] The flexible display device according to [9] or [10], further comprising a polarizing plate.

[12] As a method for producing an optical laminate according to any one of [1] to [8],

(a) a process of applying a varnish containing at least a polyimide resin and/or a polyamide resin, and a solvent on a support and drying to form a coating film,

(b) the step of peeling the coating film from the support,

(c) heating the peeled coating film to obtain a film, and

(d) A manufacturing method including at least a step of laminating a functional layer on at least one side of the film to obtain an optical laminate.

ADVANTAGE OF THE INVENTION According to this invention, the optical laminated body excellent in optical homogeneity, the flexible display device provided with the said optical laminated body, and the manufacturing method of the said optical laminated body can be provided.

1 is a schematic diagram showing an example of an arrangement in a step of obtaining a projection image.
Fig. 2 is a schematic diagram for explaining an arrangement in a step of obtaining a projection image in Examples and Comparative Examples.
3 is a diagram for explaining _{Y max} , X _max, and X _cen in a line profile.
4 is a diagram showing a line profile before normalization obtained from the projection image of Example 1. FIG.
5 is a diagram showing a normalized line profile obtained from the projection image of Example 1. FIG.
6 is a diagram showing a normalized line profile obtained from a background image of Example 1. FIG.
7 is a diagram showing a line profile obtained by subtracting the normalized line profile obtained from the background image of Example 1 from the normalized line profile obtained from the projection image of Example 1. FIG.
8 is a diagram showing a line profile obtained by smoothing the line profile obtained by subtracting the normalized line profile obtained from the background image of Example 1 from the normalized line profile obtained from the projection image of Example 1. FIG.

Hereinafter, an embodiment of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiments described herein, and various changes can be made without departing from the spirit of the present invention.

In one aspect of the present invention, the optical laminate of the present invention includes an optical film containing a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one side of the optical film. as,

Line profiles in directions h and v perpendicular to each other in the film inverse space obtained by Fourier transform of the projection image obtained by the projection method using the optical film are referred to as line profiles h and v, respectively, in the projection method Line profiles in directions h'and v'that are orthogonal to each other in a background inverse space obtained by Fourier transform of a background image obtained without using the optical film are referred to as line profiles h'and v', respectively, and line profiles line profile h from h to maximum intensity of the "by subtracting the obtained line profile (h-h ') is called Y _mh, and the frequency showing the maximum intensity Y _mh called X _mh, obtained by subtracting the line profile v' from the line profile v _Assuming that the maximum intensity of the line profile (v-v') is _{Y mv} and the frequency representing the maximum intensity Y _{mv is X mv} , _{both Y mh} and Y _mv are 40 or less, and Y _mh , Y _mv , X _mh and X _mv is the relationship:

It is an optical laminated body that satisfies.

In another aspect of the present invention, the optical laminate of the present invention has an optical film containing a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one side of the optical film. As a sieve,

The line profiles in directions h and v perpendicular to each other in the film inverse space obtained by Fourier transform of the projection image obtained by the projection method using the optical laminate are referred to as line profiles h and v, respectively, and in the projection method In the background inverse space obtained by Fourier transform of the background image obtained without using the optical laminate, the line profiles in directions h'and v'perpendicular to each other are referred to as line profiles h'and v', respectively, a line for the maximum strength of the profile line profile h 'line profile (h-h obtained by subtracting') from h and that Y _mh, the frequency showing the maximum intensity Y _mh called X _mh, line profile v 'from the line profile v If the called a maximum intensity of the line profile (v-v ') obtained by subtracting Y _mv, and the frequency showing the maximum intensity Y _mv as X _mv, Y _mh and Y _mv are all less than _{40, Y mh, Y mv,} X _mh and X _mv have the following relationship:

It is an optical laminated body that satisfies. Here, directions h and h'are directions corresponding to each other, and directions v and v'are directions corresponding to each other. Corresponding to these directions means that the azimuth angles are the same.

The optical laminate of the present invention satisfies the above characteristics as a result of using the optical film contained in the optical laminate of the present invention or the optical laminate of the present invention as a measurement film _{and evaluating the Y mh etc.} It is an optical laminate. The optical laminate of the present invention satisfying such characteristics has high optical homogeneity. The optical layered product of the present invention has excellent optical homogeneity and is particularly preferably used as an optical layered product in an image display device. Here, the optical homogeneity of the film is closely related to the non-uniformity of the plane shape, the thickness of the film, the non-uniformity of orientation, and the like, and when these non-uniformities occur, the optical homogeneity decreases. For this reason, the optical laminated body of the present invention having excellent optical homogeneity can be said to be a film in which unevenness such as surface shape unevenness, thickness unevenness, and orientation unevenness is reduced.

The optical film contained in the optical laminate of the present invention, or a film inverse spatial image obtained by Fourier transform of a projection image obtained by a projection method using the optical laminate of the present invention as a measurement film, and in the projection method, the The background inverse space image obtained by Fourier transform of a background image obtained without using a measurement film is not particularly limited as long as it is obtained by Fourier transform from a projection image and a background image, respectively, but, for example,

(1) a step of obtaining a projection image by a projection method in which light from a light source is irradiated onto a measurement film (optical film or optical laminate), and light transmitted through the measurement film is projected onto a projection surface,

(2) The step of obtaining a background image by projecting light from a light source onto a projection surface without using a measurement film in the projection method of step (1),

And,

(3) The projection image obtained in step (1) and the background image obtained in step (2) are digitized by gray scale, respectively, and the digitized image data is Fourier transformed to form an inverse space image (film inverse space image and background inverse space). It can be obtained by the process of obtaining phase). By evaluating the surface quality of the measurement film using the reverse spatial image, it is possible to analyze the shade and period of non-uniformity.

A method of obtaining an inverse spatial image by Fourier transform from a projection image by a projection method of a measurement film is not particularly limited, but for example, a method described later for the evaluation process may be used.

Next, (4) each line profile in the two directions orthogonal in the inverse space of the background image is subtracted from each line profile in the two directions orthogonal in the inverse space of the projection image, and the blank-corrected line profile is obtained. obtaining process, and, (5) the maximum intensity of the blank, the corrected line profile obtained in step (4), Y _max (respectively, Y _mh and Y _mv), and the maximum intensity in each of the line profiles Y _max (Y _mh and Y _mv ) And measure the frequency X _max (X _mh and X _mv ). For example, a case where a line profile is created in each of the horizontal direction (h1 direction) and vertical direction (v1 direction) passing through the center of the reverse space will be described below. The line profile is shown, for example, as a graph showing the frequency on the X-axis and the intensity on the Y-axis as shown in FIG. 3. _{And, the maximum intensity Y max} in the line profile in the horizontal direction (h1 direction) is _{called Y mh1} , and the median value X _cen of all frequencies in the blank corrected line profile is subtracted from the frequency representing the maximum intensity Y _{mh1. Let max} be X _mh1 . _{In addition, the maximum intensity Y max} in the line profile in the vertical direction (v1 direction) is _{called Y mv1} , and the median value X _cen of all frequencies in the blank corrected line profile is subtracted from the frequency representing the maximum intensity Y _{mv1, X Let max} be X _mv1 . In the above example, the horizontal direction (h1 direction) and the vertical direction (v1 direction) passing through the center of space are selected as two orthogonal directions, but if the two directions (h direction and v direction) are orthogonal to each other, It is not limited and may be two directions not passing through the center, and may not be a horizontal direction and a vertical direction. In addition, in this specification, the "blank-corrected line profile" means each line in the two directions orthogonal in the reverse space of the background image from the line profile in two directions orthogonal in the reverse space of the projection image. It means the line profile obtained by subtracting each profile. By the above operation, the baseline of the line profile in the reverse space of the projected image can be corrected.

_{The Y mh} and Y _mv obtained by using the optical film contained in the optical laminate of the present invention as a measurement film are both 40 or less. When Y _mh or Y _mv exceeds 40, it cannot be said that the optical homogeneity of the optical film is sufficient, and the optical homogeneity of the optical laminate is sometimes insufficient. In particular, it cannot be said that the optical homogeneity of the optical layered product including such an optical film is sufficient for use in an image display device, and distortion of an image cannot be sufficiently reduced. From the viewpoint of easy to increase the optical homogeneity of the optical laminate and to improve image visibility in an image display device, Y _mh and Y _mv are preferably 35 or less, more preferably 32 or less, and still more preferably 30 or less. , More preferably 28 or less, particularly preferably 26 or less. The _{smaller Y mh} and Y _mv are, the better, and the lower limit is not particularly limited and may be 0 or more, and usually 1 or more. _{About the said Y mh} and Y _mv obtained using the optical laminated body of this invention as a measurement film, the said preferable base material is similarly suitable.

Using the optical film contained in the optical laminate of the present invention as a measurement film, Y _mh , Y _mv , X _mh and X _mv obtained as described above have the following relationship:

Meets. If the value of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 exceeds 30, the optical homogeneity is not sufficient, so distortion of the screen is likely to occur. The upper limit of the value of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 is preferably 25 or less, more preferably 22 or less, and more preferably, from the viewpoint of increasing optical homogeneity more easily. 20 or less, more preferably 19.5 or less, more preferably 19 or less, more preferably 18 or less, still more preferably 17 or less, more preferably 16 or less, more preferably 14 or less, more preferably 13 Hereinafter, it is particularly preferably 9 or less. The smaller the value of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 is better, and the lower limit thereof is not particularly limited and may be 0 or more, and usually 0.5 or more. _{About the said Y mh} , Y _mv , X _mh and X _mv obtained using the optical laminated body of this invention as a measurement film, the said preferable base material is similarly suitable.

As the measurement film, the median of the total frequency in the blank-corrected line profile obtained as described above using the optical film contained in the optical laminate of the present invention or the optical laminate of the present invention is referred to _{as X cen.} For example, in the line profile shown in Fig. 3, the total frequency is 90 cm ^-1 , and the median value of 45 cm ^-1 is X _cen . Here, X _{cen and X mh} and X _mv obtained as described above have the following relationship:

It is desirable to meet. In addition, in the above formulas, it is preferable that _{X m} represents X _mh or X _mv , and _{both of X mh} and X _{mv satisfy the above formula.} The lower limit of |X _m -X _cen | is more preferably 0.5 cm ^-1 or more, and still more preferably 1.0 cm ^-1 or more. In addition, _{the upper limit of |X m} -X _cen | is more preferably 8.0 cm ^-1 or less, and still more preferably 6.0 cm ^-1 or less. _{It is preferable that X mh} and X _mv in an optical film or an optical laminate satisfy the above relationship in view of providing optical homogeneity that is not visually recognized as non-uniformity and considering productivity.

The pencil hardness of at least one surface of the optical laminate of the present invention is preferably H or more, more preferably 2H or more, still more preferably 3H or more, and particularly preferably 4H or more. When the pencil hardness of at least one surface of the optical laminate is equal to or higher than the above hardness, it is easy to prevent scratches and the like on the surface of the optical laminate. It is preferable that the said pencil hardness is the pencil hardness of the side which has a functional layer (preferably a hard coat layer) of the optical laminated body of this invention. In addition, pencil hardness can be measured according to JIS K 5600-5-4:1999, for example, it can be measured by the method described in Examples.

The surface resistivity of at least one surface of the optical laminate of the present invention is preferably 1.0×10 ¹³ Ω/sq or less, more preferably 5.0×10 ¹² Ω/sq or less, and more preferably 1.0×10 ¹² Ω /sq or less. When the surface resistivity is less than or equal to the above upper limit, it is easy to obtain a sufficient antistatic function. ^{The surface resistivity of at least one surface of the optical laminate of the present invention is preferably 1.0×10 7} Ω from the viewpoint of easy to ensure operability of the touch panel when the optical laminate of the present invention is used in combination with a touch panel. /sq or more, more preferably 5.0×10 ⁷ Ω/sq or more, and still more preferably 1.0×10 ⁸ Ω/sq or more. It is preferable that the said surface resistivity is the surface resistivity of the surface which has a functional layer (preferably an antistatic functional layer) of the optical laminated body of this invention. In addition, the surface resistivity can be measured according to JIS K 6911, for example, it can be measured by the method described in Examples.

In the optical laminate of the present invention, the reflectance of the optical laminate when light is incident from the surface having the functional layer is preferably 3.0% or less, more preferably 2.0% or less, and still more preferably 1.0% or less. to be. In addition, the reflectance in this specification means a luminous sensitivity correction reflectance, and specifically, a spectral reflectance in the range of 350 to 900 nm wavelength at a reflection angle of 12 degrees when light is incident at an incident angle of 12 degrees (i.e. It refers to the reflectance obtained by correcting the luminous intensity of the positive reflectance in the figure) using a 2-degree field of view (C light source) of JIS Z 8701. Reflectance can be measured using a spectrophotometer or the like. In measuring the reflectance, for the purpose of excluding the possibility that reflection from a surface opposite to the surface of the functional layer through which light is incident may affect the measured value, and for the purpose of preventing warpage of the optical laminate, the , A sample bonded to a black plate (such as a black acrylic plate) using an optically transparent adhesive on the side opposite to the surface of the functional layer to which light is incident is used as a sample for measurement.

The yellowness (YI value) of the optical layered product of the present invention is preferably 3.0 or less, more preferably 2.7 or less, still more preferably 2.5 or less, and particularly preferably 2.0 or less. When the yellowness of the optical laminate is equal to or less than the above upper limit, transparency is easily improved, and visibility is easily improved when used for, for example, a front plate of a display device. The yellowness is usually -5 or more, preferably -2 or more, more preferably 0 or more, still more preferably 0.3 or more, still more preferably 0.5 or more, and particularly preferably 0.7 or more. Yellowness (YI) is based on JIS K 7373:2006, using an ultraviolet-visible near-infrared spectrophotometer to measure the transmittance of light of 300 to 800 nm, and obtain the three stimulus values (X, Y, Z). , YI = 100 × (1.2769X-1.0592Z) / Y can be calculated based on the equation.

The total light transmittance of the optical layered product of the present invention is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. When the total light transmittance is more than the above lower limit, it is easy to increase the visibility when the optical laminate is assembled into an image display device. Since the optical laminate of the present invention exhibits high optical homogeneity and high transmittance, it is possible to suppress the luminous intensity of a display element, etc., required to obtain a constant brightness, compared to the case of using a film having a low transmittance, for example. It becomes. For this reason, power consumption can be reduced. For example, in the case of assembling the optical laminate of the present invention in a display device, there is a tendency that a bright display can be obtained even when the amount of light of the backlight is reduced, which can contribute to energy saving. The upper limit of the total light transmittance is usually 100% or less. In addition, the total light transmittance can be measured using a haze computer according to JIS K7361-1:1997, for example. The total light transmittance may be a total light transmittance in the range of the thickness of the optical laminate to be described later.

The haze of the optical layered product of the present invention is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, even more preferably 0.5% or less, particularly preferably 0.3% or less. . When the haze of the optical laminate is equal to or less than the above upper limit, transparency becomes good, and when used for, for example, a front plate of an image display device, the visibility of an image is easily improved. In addition, the lower limit of haze is usually 0.01% or more. In addition, haze can be measured using a haze computer according to JIS K 7136:2000.

The thickness of the optical laminate of the present invention may be appropriately adjusted according to the application, but is preferably 25 µm or more, more preferably 27 µm or more, still more preferably 30 µm or more, preferably 100 µm or less, more It is preferably 90 µm or less, more preferably 85 µm or less. The thickness of the optical laminate can be measured by a film thickness meter or the like, for example, by the method described in Examples.

The optical layered product of the present invention has an optical film containing a polyimide resin and/or a polyamide resin, and a functional layer laminated on at least one surface of the optical film. From the viewpoint of easy production of an optical film with high homogeneity having the above characteristics related to Y _mh, etc., and/or from the viewpoint of easy production of an optical laminate having high homogeneity having the above characteristics, the optical layer in the optical laminate of the present invention The film is preferably a cast film. In the present specification, a cast film means, for example, casting a solution, dispersion, or melt containing the resin on a suitable support to form a coating film by heating, cooling, drying, etc. The film obtained by peeling the said coating film from the said support body is shown. The film thus obtained contains at least a polyimide-based resin and/or a polyamide-based resin, and optionally a trace amount of a solvent.

The optical film in the optical layered product of the present invention contains a polyimide resin and/or a polyamide resin. In the optical laminate of the present invention, the optical film may contain one type of polyimide type resin or polyamide type resin, or may contain two or more types of polyimide type resin and/or polyamide type resin.

<Polyimide resin and polyamide resin>

In the optical laminate of the present invention, the optical film contains a polyimide resin and/or a polyamide resin. A polyimide resin is a resin containing a repeating structural unit containing an imide group (hereinafter, sometimes referred to as a polyimide resin), and a resin containing a repeating structural unit containing both an imide group and an amide group ( Hereinafter, at least one resin selected from the group consisting of polyamide-imide resins in some cases) is shown. In addition, the polyamide-based resin refers to a resin containing a repeating structural unit containing an amide group.

In a preferred embodiment of the present invention, the polyimide resin is a polyimide resin having a structural unit represented by formula (1), or a structural unit represented by formula (1) and a structural unit represented by formula (2). It is preferably a polyamideimide resin having. Moreover, it is preferable that the polyamide resin is a polyamide resin which has a structural unit represented by Formula (2). Hereinafter, formulas (1) and (2) will be described, but the description of formula (1) relates to both polyimide resin and polyamideimide resin, and the description of formula (2) is poly It relates to both an amide resin and a polyamide-imide resin.

The structural unit represented by formula (1) is a structural unit formed by reacting a tetracarboxylic acid compound and a diamine compound, and the structural unit represented by formula (2) is a structural unit formed by reacting a dicarboxylic acid compound and a diamine compound to be.

In formula (2), Z is a divalent organic group, preferably a C 1 to C 8 hydrocarbon group or a fluorine-substituted C 1 to C 8 hydrocarbon group may be substituted, and a C 4 to C 40 divalent oil It is a device, and more preferably, it may be substituted with a C1-C8 hydrocarbon group or a fluorine-substituted C1-C8 hydrocarbon group, and it is a C4-C40 divalent organic group having a cyclic structure. As a cyclic structure, an alicyclic, an aromatic ring, and a heterocyclic structure are mentioned. As the organic group of Z, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( Among the bond hands of the groups represented by 28) and formula (29), a group in which two non-adjacent groups are substituted with hydrogen atoms and a divalent chain hydrocarbon group having 6 or less carbon atoms are exemplified, and the heterocyclic structure of Z has a thiophene ring skeleton. Gi is illustrated. From the viewpoint of easily suppressing the yellowness of the optical film (reducing the YI value), groups represented by formulas (20) to (27) and groups having a thiophene ring skeleton are preferred.

In one embodiment of the present invention, the polyamide resin and the polyamideimide resin may contain a plurality of types of Z, and the plurality of types of Z may be the same or different from each other. In particular, from the viewpoint of easy to increase the surface hardness of the optical film and from the viewpoint of easy to improve the optical properties, at least a part of Z is represented by formula (3)

[In formula (3), R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ¹ to R ^{The hydrogen atoms contained in 8} may be each independently substituted with a halogen atom,

A is, independently of each other, a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, R ⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m is an integer from 0 to 4,

* Indicates a bond hand]

It is preferable to appear as.

In formula (3), A is a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C( CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, and from the viewpoint of the bending resistance of the optical film, preferably -O- or -S- , More preferably -O-.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 6 It represents the aryl group of -12. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 2-methyl-butyl group , 3-methylbutyl group, 2-ethyl-propyl group, and n-hexyl group. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, and cyclohexyloxy group. Time, etc. As a C6-C12 aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, etc. are mentioned, for example. From the viewpoint of the surface hardness and flexibility of the optical film, R ¹ to R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms And more preferably a hydrogen atom. Here, ^{the hydrogen atoms contained in R 1} to R ⁸ may be each independently substituted with a halogen atom.

R ⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 2-methyl -Butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group, n-heptyl group, n-octyl group, tert-octyl group, n-nonyl group, n-decyl group, and the like. And these may be substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The polyimide resin or polyamide resin may contain a plurality of types of A, and the plurality of types of A may be the same or different from each other.

In Formula (3), m is an integer in the range of 0 to 4, and when m is within this range, the bending resistance and elastic modulus of the optical film tend to be favorable. In addition, in the formula (3), m is preferably an integer in the range of 0 to 3, more preferably 0 to 2, still more preferably 0 or 1, and particularly preferably 0. When m is within this range, it is easy to improve the bending resistance and elastic modulus of the optical film. In addition, Z may contain 1 type or 2 or more types of structural units represented by Formula (3), and especially the value of m from a viewpoint of improvement of the elastic modulus and bending resistance of an optical film, and reduction of yellowness (YI value) These different two or more kinds of structural units, preferably two kinds of structural units having different values of m may be included. In that case, it is preferable that the resin contains a structural unit represented by formula (3) in which m is 0 in Z from the viewpoint of easy expression of high elastic modulus, bending resistance, and low yellowness (YI value) of the optical film. , In addition to the structural unit, it is more preferable to further contain a structural unit represented by formula (3) in which m is 1.

In a preferred embodiment of the present invention, the resin has a structural unit in which m = 0 and R ⁵ to R ⁸ are hydrogen atoms as a structural unit represented by formula (3). In a more preferred embodiment of the present invention, the resin is a structural unit represented by formula (3), m=0, and a structural unit in which R ⁵ to R ⁸ is a hydrogen atom, and formula (3'):

It has a constituent unit represented by In this case, it is easy to improve the surface hardness and the bending resistance of the optical film, and it is easy to reduce the yellowness.

In a preferred embodiment of the present invention in which the optical laminate has an optical film containing a polyamideimide resin, the sum of the structural units represented by formula (1) and the structural units represented by formula (2) of the polyamideimide resin When is set to 100 mol%, the proportion of the constituent units represented by the formula (3) is preferably 20 mol% or more, more preferably 30 mol% or more, more preferably 40 mol% or more, particularly preferably It is 50 mol% or more, most preferably 60 mol% or more, preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less. When the ratio of the structural units represented by the formula (3) is equal to or greater than the above lower limit, it is easy to increase the surface hardness of the optical film, and it is easy to increase the bending resistance and the elastic modulus. When the ratio of the structural units represented by the formula (3) is less than or equal to the above upper limit, an increase in the viscosity of the resin-containing varnish due to hydrogen bonding between amide bonds derived from the formula (3) is suppressed, and the workability of the film is easily improved.

In addition, when the polyamideimide resin has a structural unit of formula (3) in which m = 1 to 4, the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) of the polyamideimide resin is 100 When set to mol%, the proportion of the constituent units of formula (3) in which m is 1 to 4 is preferably 3 mol% or more, more preferably 5 mol% or more, more preferably 7 mol% or more, particularly It is preferably 9 mol% or more, preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, particularly preferably 30 mol% or less. When the ratio of the structural unit of formula (3) in which m is 1 to 4 is not less than the above lower limit, it is easy to increase the surface hardness and the bending resistance of the optical film. When the ratio of the constituent units of formula (3) in which m is 1 to 4 is less than or equal to the above upper limit, the increase in viscosity of the resin-containing varnish due to hydrogen bonding between the amide bonds derived from formula (3) is suppressed, and the processability of the film is improved. Easy to do In addition, the content of the structural unit represented by Formula (1), Formula (2), or Formula (3) ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of the raw material.

In a preferred embodiment of the present invention, the Z in the polyamide resin or polyamideimide resin is preferably 30 mol% or more, more preferably 40 mol% or more, still more preferably 45 mol% or more, further Preferably 50 mol% or more, particularly preferably 70 mol% or more is a structural unit represented by formula (3) wherein m is 0 to 4. If more than the said lower limit of Z is a structural unit represented by Formula (3) in which m is 0-4, it is easy to increase the surface hardness of an optical film, and it is easy to increase bending resistance and elastic modulus. Further, 100 mol% or less of Z in the polyamide resin or polyamide-imide resin may be a structural unit represented by formula (3) in which m is 0 to 4. In addition, the ratio of the structural unit represented by formula (3) in which m is 0 to 4 in the resin ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of the raw material.

In a preferred embodiment of the present invention, the Z in the polyamide resin or polyamideimide resin is preferably 5 mol% or more, more preferably 8 mol% or more, still more preferably 10 mol% or more, particularly Preferably, 12 mol% or more is represented by formula (3) wherein m is 1 to 4. When the above lower limit of Z of the polyamideimide resin is expressed by the formula (3) in which m is 1 to 4, it is easy to increase the surface hardness of the optical film, and also it is easy to increase the bending resistance and elastic modulus. Further, of Z, preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, particularly preferably 30 mol% or less, m is 1 to 4 formula (3 It is preferable to appear as ). When the above upper limit of Z is represented by formula (3) in which m is 1 to 4, the viscosity increase of the resin-containing varnish due to hydrogen bonds between amide bonds derived from formula (3) in which m is 1 to 4 is suppressed, It is easy to improve the processability of the film. In addition, the ratio of the structural unit represented by Formula (3) in which m is 1 to 4 in the resin ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of the raw material.

In formulas (1) and (2), X represents, independently of each other, a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms, more preferably 4 to 40 carbon atoms having a cyclic structure Represents a divalent organic group of. As a cyclic structure, an alicyclic, an aromatic ring, and a heterocyclic structure are mentioned. In the organic group, the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in that case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. In one embodiment of the present invention, the polyimide resin or polyamideimide resin may contain a plurality of types of X, and the plurality of types of X may be the same or different from each other. As X, a group represented by formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) and formula (18) ; A group in which a hydrogen atom in the groups represented by formulas (10) to (18) is substituted with a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group; And a chain hydrocarbon group having 6 or less carbon atoms.

In formulas (10) to (18), * represents a bond hand,

V ¹ , V ² and V ³ are each independently a single bond, -O-, -S-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -CO-, or -N(Q)-. Here, Q represents a C1-C12 monovalent hydrocarbon group which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include the groups described above for ^{R 9.}

In one example, V ¹ and V ³ are a single bond, -O- or -S-, and V ² is -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) _2- Or -SO ₂ -. The ^{bonding positions for each ring with V 1} and V ² , and the bonding positions for each ring with V ² and V ³ are independently of each other, preferably meta-position or para-position with respect to each ring, and more preferably Hagi is the para position.

Among the groups represented by formulas (10) to (18), formulas (13), formulas (14), formulas (15), formulas (16) and formulas ( The group represented by 17) is preferred, and the group represented by formula (14), formula (15) and formula (16) is more preferred. In addition, V ¹ , V ² and V ³ are preferably a single bond, -O- or -S- independently of each other from the viewpoint of easy to increase the surface hardness and flexibility of the optical film, and a single bond or -O- It is more preferable that it is.

In a preferred embodiment of the present invention, at least a part of a plurality of X in formulas (1) and (2) is formula (4):

[In formula (4), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ¹⁰ to R ¹⁷ The hydrogen atoms contained in may be independently of each other and may be substituted with a halogen atom, and * indicates a bonding hand]

It is a structural unit represented by. When at least a part of a plurality of X in formulas (1) and (2) is a group represented by formula (4), it is easy to increase the surface hardness and transparency of the optical film.

In formula (4), R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and 1 to 6 carbon atoms. Represents an alkoxy group or an aryl group having 6 to 12 carbon atoms. As a C1-C6 alkyl group, a C1-C6 alkoxy group, or a C6-C12 aryl group, the C1-C6 alkyl group in formula (3), a C1-C6 alkoxy group, or C6-C12 Examples of the aryl group of are exemplified. R ¹⁰ to R ¹⁷ independently of each other, preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, wherein R ¹⁰ to R ¹⁷ The contained hydrogen atoms may be substituted with halogen atoms independently of each other. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. R ¹⁰ to R ¹⁷ are, independently of each other, more preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group, particularly preferably from the viewpoint of surface hardness, transparency and bending resistance of the optical film. R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are a hydrogen atom, R ¹¹ and R ¹⁷ are a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, particularly preferably R ¹¹ and R ¹⁷ are methyl or trifluoromethyl groups.

In a preferred embodiment of the present invention, the structural unit represented by formula (4) is formula (4'):

It is a structural unit represented by, that is, at least a part of a plurality of X is a structural unit represented by Formula (4'). In this case, the solubility of the polyimide resin or the polyamide resin in the solvent is increased by the skeleton containing the fluorine element, and the viscosity of the varnish is reduced while it is easy to improve the storage stability of the varnish containing the resin. It is easy to do, and it is easy to improve the workability of an optical film. Moreover, it is easy to improve the optical properties of an optical film by the skeleton containing a fluorine element.

In a preferred embodiment of the present invention, X in the polyimide resin or polyamide resin is preferably 30 mol% or more, more preferably 50 mol% or more, and still more preferably 70 mol% or more. It is represented by formula (4), especially formula (4'). When X in the above range in the polyimide resin or polyamide resin is represented by formula (4), particularly formula (4'), the solubility of the resin in the solvent is easily improved by the skeleton containing a fluorine element, While it is easy to improve the storage stability of the varnish containing the resin, the viscosity of the varnish is easily reduced, and the processability of the optical film is easily improved. Moreover, the optical properties of the optical film are also easily improved by the skeleton containing the fluorine element. Further, preferably, 100 mol% or less of X in the polyimide resin or polyamide resin is represented by formula (4), particularly formula (4'). X in the polyamideimide resin may be a formula (4), particularly a formula (4'). The ratio of the structural unit represented by Formula (4) of X in the resin ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of the raw material.

In the formula (1), Y represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms, and more preferably a tetravalent organic group having a cyclic structure and having 4 to 40 carbon atoms. As a cyclic structure, an alicyclic, an aromatic ring, and a heterocyclic structure are mentioned. The organic group is an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in that case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. In one embodiment of the present invention, the polyimide resin may contain a plurality of types of Y, and the plurality of types of Y may be the same or different from each other. As Y, the following formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and A group represented by formula (29); A group in which a hydrogen atom in the groups represented by the formulas (20) to (29) is substituted with a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group; And a tetravalent C6 or less chain hydrocarbon group.

In equations (20) to (29),

* Represents a bond hand,

W ¹ is a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) _{2 -Ar-} Or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom may be substituted with a fluorine atom, and a phenylene group is exemplified as a specific example.

Among the groups represented by formulas (20) to (29), groups represented by formula (26), formula (28) or formula (29) are preferred from the viewpoint of surface hardness and bending resistance of the optical film, and formula (26) The group represented by is more preferable. In addition, W ¹ _{is, independently of each other, single bonds, -O-, -CH 2} -, -CH ₂ -CH ₂ -from the viewpoint of easy to increase the surface hardness and bending resistance of the optical film and easy to reduce the yellowness. , -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -is preferably a single bond, -O-, -CH ₂ -, -CH(CH ₃ )- , -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -is more preferable, and it is more preferable that it is a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -.

In a preferred embodiment of the present invention, at least a part of a plurality of Y in formula (1) is formula (5):

[In formula (5), R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ¹⁸ to R ²⁵ The hydrogen atoms contained in may be independently of each other and may be substituted with a halogen atom,

* Indicates a bond hand]

It is a structural unit represented by. If at least a part of a plurality of Y in formula (1) is a group represented by formula (5), the solubility of the polyimide resin in the solvent is increased, and the viscosity of the varnish containing the polyimide resin is easily reduced, and the optical film It is easy to improve the workability of In addition, it is easy to improve the optical properties of the optical film.

In formula (5), R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and 1 to 6 carbon atoms. Represents an alkoxy group or an aryl group having 6 to 12 carbon atoms. As a C1-C6 alkyl group, a C1-C6 alkoxy group, and a C6-C12 aryl group, the C1-C6 alkyl group in Formula (3), a C1-C6 alkoxy group, or C6-C12 Examples of the above are mentioned as the aryl group of. R ¹⁸ to R ²⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, wherein R ¹⁸ to R ²⁵ The contained hydrogen atoms may be substituted with halogen atoms independently of each other. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R ¹⁸ to R ²⁵ are each independently a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group from the viewpoint of easy improvement of the surface hardness, bending resistance and transparency of the optical film, Even more preferably R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ and R ²⁵ are a hydrogen atom, R ²¹ and R ²² are a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, Particularly preferably, R ²¹ and R ²² are a methyl group or a trifluoromethyl group.

In a preferred embodiment of the present invention, the structural unit represented by formula (5) is formula (5'):

It is a group represented by, that is, at least a part of a plurality of Y is a structural unit represented by Formula (5'). In this case, the solubility of the polyimide resin in the solvent is increased by the skeleton containing the fluorine element, and the storage stability of the varnish containing the resin is easily improved, and the viscosity of the varnish is easily reduced. It is easy to improve the workability of Moreover, it is easy to improve the optical properties of an optical film by the skeleton containing a fluorine element.

In a preferred embodiment of the present invention, of Y in the polyimide resin, preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably 70 mol% or more, formula (5), In particular, it is represented by the formula (5'). When Y within the above range in the polyimide resin is represented by formula (5), particularly formula (5'), the solubility of the polyimide resin in the solvent is increased by the skeleton containing the fluorine element, and the resin is contained. It is easy to reduce the viscosity of the varnish to be performed, and it is easy to improve the workability of the optical film. Moreover, it is easy to improve the optical properties of an optical film by the skeleton containing a fluorine element. Further, preferably, 100 mol% or less of Y in the polyimide resin is represented by formula (5), particularly formula (5'). Y in the polyimide resin may be a formula (5), particularly a formula (5'). The ratio of the structural unit represented by the formula (5) of Y in the polyimide resin ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of the raw material.

The polyimide resin or polyamide resin may include a structural unit represented by formula (30) and/or a structural unit represented by formula (31) in addition to the structural units represented by formulas (1) and (2). .

In formula (30), Y ¹ is a tetravalent organic group, and preferably, a hydrogen atom in the organic group is an organic group in which a hydrocarbon group or a fluorine-substituted hydrocarbon group may be substituted. As Y ¹ , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and formula A group represented by (29), a group in which a hydrogen atom in the groups represented by formulas (20) to (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and a tetravalent chain hydrocarbon having 6 or less carbon atoms Gi is illustrated. In one embodiment of the present invention, a polyimide resin or a polyamide-based resin may include a plurality of types of Y ^1, Y ¹ of a plurality of species, and may be same or different from each other.

In formula (31), Y ² is a trivalent organic group, and preferably, a hydrogen atom in the organic group is an organic group in which a hydrocarbon group or a fluorine-substituted hydrocarbon group may be substituted. As Y ² , the above formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) And a group in which any one of the bond hands of the group represented by formula (29) is substituted with a hydrogen atom, and a trivalent chain hydrocarbon group having 6 or less carbon atoms are exemplified. In one embodiment of the present invention, a polyimide resin or a polyamide-based resin may include a plurality of types of Y ^2, Y ² is a plurality of types, and may be same or different from each other.

In formulas (30) and (31), X ¹ and X ² are each independently a divalent organic group, and preferably, a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. It is a device. As X ¹ and X ² , the above formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) and formula The group represented by (18); A group in which a hydrogen atom in the groups represented by formulas (10) to (18) is substituted with a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group; And a chain hydrocarbon group having 6 or less carbon atoms.

In one embodiment of the present invention, the polyimide resin or polyamide resin is a structural unit represented by formula (1) and/or formula (2), and in some cases, formula (30) and/or formula (31). It consists of structural units represented by ). In addition, from the viewpoint of optical properties, surface hardness and bending resistance of the optical film, in the polyimide resin or polyamide resin, the structural units represented by formulas (1) and (2) are formulas (1) and Based on formula (2), and optionally all structural units represented by formulas (30) and (31), preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% % Or more. In addition, in the polyimide resin or polyamide resin, the structural units represented by formulas (1) and (2) are formulas (1) and (2), and in some cases, formulas (30) and/or It is usually 100% or less based on all the structural units represented by Formula (31). In addition, the ratio ^{can be measured using, for example, 1} H-NMR, or can be calculated from the introduction ratio of raw materials.

In one embodiment of the present invention, the content of the polyimide resin and/or polyamide resin in the optical film is preferably 10 parts by mass or more, and more preferably 30 parts by mass, based on 100 parts by mass of the optical film. It is mass part or more, more preferably 50 mass parts or more, preferably 99.5 mass parts or less, more preferably 95 mass parts or less. When the content of the polyimide resin and/or the polyamide resin is within the above range, it is easy to improve the optical properties and elastic modulus of the optical film.

The weight average molecular weight (Mw) of the polyimide resin or the polyamide resin is preferably 230,000 or more, more preferably 250,000 or more, in terms of standard polystyrene, from the viewpoint of easy to increase the surface hardness and bending resistance of the optical film. , More preferably 270,000 or more, particularly preferably 300,000 or more. In addition, from the viewpoint of easiness of improving the solubility of the polyamide resin or polyimide water in the solvent, and the ease of improving the stretchability and processability of the optical film, the weight average molecular weight of the resin is preferably 1,000,000 or less. , More preferably 800,000 or less, still more preferably 700,000 or less, and particularly preferably 500,000 or less. The weight average molecular weight can be obtained by performing GPC measurement, for example, in terms of standard polystyrene, and may be calculated, for example, by the method described in Examples.

In the polyamideimide resin, the content of the structural unit represented by the formula (2) is preferably 0.1 mole or more, more preferably 0.5 mole or more, and more preferably with respect to 1 mole of the structural unit represented by formula (1). Is 1.0 mol or more, particularly preferably 1.5 mol or more, preferably 6.0 mol or less, more preferably 5.0 mol or less, and still more preferably 4.5 mol or less. When the content of the structural unit represented by Formula (2) is more than the above lower limit, it is easy to increase the surface hardness of the optical film. In addition, when the content of the structural unit represented by the formula (2) is equal to or less than the above upper limit, thickening due to hydrogen bonds between the amide bonds in the formula (2) is suppressed, and workability of the optical film is easily improved.

In a preferred embodiment of the present invention, the polyimide resin or polyamide resin contained in the optical film in the optical laminate of the present invention can be introduced by, for example, the fluorinated substituent described above. A halogen atom such as a fluorine atom may be included. When the polyimide resin or the polyamide resin contains a halogen atom, it is easy to improve the elastic modulus of the optical film and also reduce the yellowness (YI value). When the elastic modulus of the optical film is high, when the optical film is used in, for example, a flexible display device, it is easy to suppress the occurrence of scratches and wrinkles in the film. Moreover, when the yellowness of an optical film is low, it becomes easy to improve the transparency and visibility of the said optical film. The halogen atom is preferably a fluorine atom. Preferred fluorine-containing substituents in order to contain a fluorine atom in the polyimide resin or polyamide resin include, for example, a fluoro group and a trifluoromethyl group.

The content of the halogen atom in the polyimide resin or polyamide resin is based on the mass of the polyimide resin or polyamide resin, preferably 1 to 40 mass%, more preferably 5 to 40 It is mass%, more preferably 5-30 mass%. When the content of the halogen atom is more than the above lower limit, the elastic modulus of the optical film is further improved, the absorption rate is lowered, the yellowness is further reduced, and transparency and visibility are more easily improved. When the content of the halogen atom is less than or equal to the above upper limit, synthesis of the resin becomes easy.

The imidation ratio of the polyimide resin and the polyamideimide resin is preferably 90% or more, more preferably 93% or more, and still more preferably 96% or more. From the viewpoint of easy to increase the optical homogeneity of the optical film and/or optical laminate, it is preferable that the imidation ratio is more than the above lower limit. In addition, the upper limit of the imidation ratio is 100% or less. The imidation ratio is the ratio of the molar amount of imide bonds in the polyimide resin and the polyamideimide resin to a value of twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide resin or the polyamideimide resin. Show. In addition, when the polyimide resin and the polyamideimide resin contain a tricarboxylic acid compound, a value of twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide resin and the polyamideimide resin, and tricar The ratio of the molar amount of imide bonds in the polyimide resin and the polyamide-imide resin to the sum of the molar amounts of the structural units derived from the present acid compound is shown. In addition, the imidation ratio can be calculated|required by an IR method, an NMR method, etc., and, for example, in an NMR method, it can measure by the method described in Examples.

For the polyimide resin and the polyamide resin, a commercial item may be used. As a commercial product of a polyimide resin, Neopurim (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd. and KPI-MX300F manufactured by Kawamura Industrial Co., Ltd. are mentioned, for example.

Regarding various properties of the optical laminate of the present invention, properties such as yellowness, surface hardness, optical properties, bending resistance, flexibility, elastic modulus, transparency, visibility, and water absorption of the optical laminate are determined by the yellowness of the optical film and the surface. When hardness, optical properties, bending resistance, flexibility, elastic modulus, transparency, visibility, water absorption, etc. are improved, it tends to be possible to improve similarly. Characteristics such as surface hardness and pencil hardness of the surface having a functional layer of the optical laminate are likely to be influenced by the kind of the functional layer.

<The manufacturing method of resin>

The polyimide resin can be produced using, for example, a tetracarboxylic acid compound and a diamine compound as main raw materials, and the polyamideimide resin includes, for example, a tetracarboxylic acid compound, a dicarboxylic acid compound, and a diamine compound. It can be manufactured using a raw material, and a polyamide resin can be manufactured using, for example, a dicarboxylic acid compound and a diamine compound as main raw materials. Here, it is preferable that the dicarboxylic acid compound contains a compound represented by at least formula (3").

[In formula (3"), R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ¹ to The ^{hydrogen atoms contained in R 8} may be each independently substituted with a halogen atom,

A is a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -,- SO ₂ -, -S-, -CO- or -N(R ⁹ )-,

R ⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m is an integer from 0 to 4,

R ³¹ and R ³² are, independently of each other, a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group or a chlorine atom. Show.]

In a preferred embodiment of the present invention, the dicarboxylic acid compound is a compound represented by formula (3") in which m is 0. As a dicarboxylic acid compound, in the compound represented by formula (3") in which m is 0 In addition, it is more preferable to use a compound represented by formula (3") in which A is an oxygen atom. Further, in another preferred embodiment, the dicarboxylic acid compound is a formula wherein R ³¹ and R ³² are chlorine atoms. It is a compound represented by (3"). Moreover, you may use a diisocyanate compound instead of a diamine compound.

Examples of the diamine compound used in the production of resin include aliphatic diamine, aromatic diamine, and mixtures thereof. In addition, in this embodiment, "aromatic diamine" refers to a diamine in which an amino group is directly bonded to an aromatic ring, and an aliphatic group or other substituent may be included in a part of the structure. This aromatic ring may be a monocyclic ring or a condensed ring, and although a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, etc. are illustrated, it is not limited to these. Among these, preferably, it is a benzene ring. In addition, "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and an aromatic ring or other substituent may be included in a part of the structure.

Examples of aliphatic diamines include acyclic aliphatic diamines such as hexamethylenediamine, and 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine and 4, Cyclic aliphatic diamines, such as 4'-diaminodicyclohexylmethane, etc. are mentioned. These can be used alone or in combination of two or more.

As an aromatic diamine, for example, p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2, Aromatic diamines having one aromatic ring, such as 6-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-dia Minodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis (4-(4-aminophenoxy)phenyl) sulfone, bis ( 4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane , 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (sometimes referred to as TFMB), 4,4'-bis(4- Aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3- And aromatic diamines having two or more aromatic rings, such as chlorophenyl)fluorene and 9,9-bis(4-amino-3-fluorophenyl)fluorene. These can be used alone or in combination of two or more.

The aromatic diamine is preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether. , 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis (4-(4-aminophenoxy)phenyl] Sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy) )Phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (TFMB), 4,4'-bis (4-aminophenoxy) Si) biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diamino Diphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl] Propane, 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (TFMB), 4,4'-bis (4-aminophenoxy) ratio It is phenyl. These can be used alone or in combination of two or more.

Among the diamine compounds, it is preferable to use at least one selected from the group consisting of aromatic diamines having a biphenyl structure from the viewpoints of high surface hardness, high transparency, high flexibility, high bending resistance and low colorability of the optical film. Consisting of 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-diaminodiphenyl ether It is more preferable to use one or more selected from the group, and even more preferably 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB).

Examples of the tetracarboxylic acid compound used in the production of the resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic acid dianhydride; And aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride and the like. Tetracarboxylic acid compounds may be used alone or in combination of two or more. The tetracarboxylic acid compound may be a tetracarboxylic acid compound analog such as an acid chloride compound other than dianhydride.

Specific examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydride, monocyclic aromatic tetracarboxylic dianhydride, and condensed polycyclic aromatic tetracarboxylic dianhydride. As non-condensed polycyclic aromatic tetracarboxylic dianhydride, for example, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3 ,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl) Propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'- (hexafluoroisopropylidene) diphthalic acid dianhydride (6 FDA may be stated) , 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl) )Ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride And 4,4'-(p-phenylenedioxy)diphthalic acid dianhydride, and 4,4'-(m-phenylenedioxy)diphthalic acid dianhydride. In addition, examples of monocyclic aromatic tetracarboxylic dianhydride include 1,2,4,5-benzenetetracarboxylic dianhydride, and condensed polycyclic aromatic tetracarboxylic dianhydride include, for example 2,3,6,7-naphthalene tetracarboxylic dianhydride is mentioned.

Among these, preferably 4,4'-oxydiphthalic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2',3,3'-benzophenone tetracarboxylic acid Dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-di Phenylsulfonetetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis( 3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane Dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-di Carboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic acid 2 Anhydride and 4,4'-(m-phenylenedioxy)diphthalic dianhydride, more preferably 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyl Tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), bis(3,4) -Dicarboxyphenyl)methane dianhydride and 4,4'-(p-phenylenedioxy)diphthalic acid dianhydride. These can be used alone or in combination of two or more.

As the aliphatic tetracarboxylic dianhydride, a cyclic or acyclic aliphatic tetracarboxylic dianhydride can be mentioned. Cyclic aliphatic tetracarboxylic dianhydride is tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4- Cycloalkanetetracarboxylic dianhydrides such as cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3, 5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, and positional isomers thereof. These can be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, and 1,2,3,4-pentanetetracarboxylic dianhydride, and the like. It can be used as or in combination of two or more. Further, a cyclic aliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride may be used in combination.

Among the tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,3',4, from the viewpoint of high surface hardness, high transparency, high flexibility, high flexural resistance, and low colorability of the optical film. 4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3 ',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid 2 Anhydrides, and mixtures thereof are preferred, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, and mixtures thereof This is more preferable, and 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) is more preferable.

As the dicarboxylic acid compound used in the production of the resin, terephthalic acid, 4,4'-oxybisbenzoic acid, or an acid chloride compound thereof is preferably used. In addition to terephthalic acid, 4,4'-oxybisbenzoic acid, or their acid chloride compounds, other dicarboxylic acid compounds may be used. Examples of other dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their related acid chloride compounds, acid anhydrides, and the like, and may be used in combination of two or more. As a specific example, isophthalic acid; Naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; A dicarboxylic acid compound of a chain hydrocarbon having 8 or less carbon atoms and two benzoic acids are linked with a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or a phenylene group Compounds and acid chloride compounds thereof. As a specific example, 4,4'-oxybis (benzoyl chloride) and terephthaloyl chloride are preferable, and it is more preferable to use a combination of 4,4'-oxybis (benzoyl chloride) and terephthaloyl chloride.

In addition, the polyimide-based resin may be obtained by further reacting tetracarboxylic acid and tricarboxylic acid, and anhydrides and derivatives thereof, in addition to the tetracarboxylic acid compound, within a range that does not impair the various physical properties of the optical laminate. .

Examples of the tetracarboxylic acid include a water adduct of an anhydride of the tetracarboxylic acid compound.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and their related acid chloride compounds, acid anhydrides, and the like, and may be used in combination of two or more. As a specific example, an anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; Phthalic anhydride and benzoic acid are a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or a phenylene group.

In the production of the resin, the amount of the diamine compound, the tetracarboxylic acid compound and/or the dicarboxylic acid compound to be used can be appropriately selected according to the ratio of the respective structural units of the desired polyimide resin and polyamide resin.

In the production of the resin, the reaction temperature of the diamine compound, the tetracarboxylic acid compound, and the dicarboxylic acid compound is not particularly limited, but, for example, 5 to 350°C, preferably 20 to 200°C, more preferably 25 to It is 100℃. The reaction time is also not particularly limited, but is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be carried out in an inert atmosphere or under reduced pressure conditions. In a preferred embodiment, the reaction is carried out while stirring under normal pressure and/or an inert gas atmosphere. Moreover, it is preferable to perform reaction in a solvent inert to reaction. The solvent is not particularly limited as long as it does not affect the reaction, and examples include water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy- Alcohol solvents such as 2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, γ-valerolactone, propylene glycol methyl ether acetate, and ethyl lactate; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; Aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; Alicyclic hydrocarbon solvents such as ethylcyclohexane; Aromatic hydrocarbon solvents such as toluene and xylene; Nitrile solvents such as acetonitrile; Ether solvents such as tetrahydrofuran and dimethoxyethane; Chlorine-containing solvents such as chloroform and chlorobenzene; Amide solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF); Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; Carbonate-based solvents such as ethylene carbonate and propylene carbonate; And combinations thereof (mixed solvents), and the like. Among these, from the viewpoint of solubility, an amide solvent can be suitably used.

In the imidization step in the production of a polyimide resin, imidization can be performed in the presence of an imidization catalyst. Examples of the imidation catalyst include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; Alicyclic amines (monocyclic) such as N-ethylpiperidine, N-propylpiperidine, N-butylpyrrolidine, N-butylpiperidine, and N-propylhexahydroazepine; Alicyclic amines (polycyclic) such as azabicyclo[2.2.1]heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane, and azabicyclo[3.2.2]nonane; And pyridine, 2-methylpyridine (2-picoline), 3-methylpyridine (3-picoline), 4-methylpyridine (4-picoline), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine. , 2,4-dimethylpyridine, 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and aromatic amines such as isoquinoline. . Further, from the viewpoint of facilitating the imidation reaction, it is preferable to use an acid anhydride together with the imidation catalyst. Examples of the acid anhydride include conventional acid anhydrides used in the imidation reaction, and specific examples thereof include aliphatic acid anhydrides such as acetic anhydride, propionic anhydride and butyric anhydride, and aromatic acid anhydrides such as phthalic acid.

Polyimide resins and polyamide resins are isolated by conventional methods such as filtration, concentration, extraction, crystallization, recrystallization, and separation means such as column chromatography, or a combination of these. (單離) (separation and purification) may be used, and in a preferred embodiment, a large amount of alcohol such as methanol is added to a reaction solution containing a transparent polyamideimide resin to precipitate the resin, and concentrating, filtering, drying, etc. , Can be isolated.

<filler>

In the optical laminated body of the present invention, the optical film may contain at least one type of filler. Examples of the filler include organic particles and inorganic particles, and preferably inorganic particles. Examples of inorganic particles include metal oxide particles such as silica, zirconia, alumina, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide, and metals such as magnesium fluoride and sodium fluoride. Fluoride particles, and the like. Among these, silica particles, zirconia particles, and alumina particles are preferable from the viewpoint of increasing the elastic modulus and/or tear strength of the obtained optical film and improving the impact resistance. There is, more preferably, silica particles are used. These fillers can be used alone or in combination of two or more.

In the optical layered product of the present invention, the optical film may contain, for example, at least one filler having an average primary particle diameter of 5 to 35 nm. In addition to having high optical properties, such an optical film also has a high tensile modulus. The tensile modulus of the optical film is preferably 4,000 MPa or more, more preferably 5,000 MPa or more, still more preferably 5,500 MPa or more, and particularly preferably 6,000 MPa or more. When the tensile modulus is more than the above lower limit, defects such as dents are less likely to occur in the optical film, and the strength of the optical film is easily increased, and durability is easily improved. The tensile modulus is preferably 10,000 MPa or less, more preferably 9,000 MPa or less. When the tensile modulus is less than or equal to the above upper limit, it is easy to improve the bending resistance of the optical film. In addition, the tensile modulus of the optical film can be measured using a tensile tester at room temperature in accordance with JIS K 7127. From the viewpoint of easy to increase the homogeneity, transparency, elastic modulus, and strength of the optical film, the average primary particle diameter of the filler is preferably 10 nm or more, more preferably 15 nm or more, and still more preferably 20 nm or more. In addition, from the viewpoint of easily enhancing the transparency of the optical film, the average primary particle diameter of the filler is preferably 30 nm or less.

The average primary particle diameter of the filler can be measured by the BET method. Specifically, the specific surface area (BET specific surface area) measured by the BET method (nitrogen adsorption BET method) can be calculated by converting the average primary particle diameter. Here, if the average primary particle diameter is d (nm), the density of the filler is ρ (g/cm ³ ), and the BET specific surface area is S (m ² /g), then d=6000/ The relationship of (S×ρ) is established. For example, when the filler is silica, the average primary particle diameter can be calculated from the BET specific surface area from the formula of d=2070/S. Further, the primary particle diameter (average primary particle diameter) may be measured by image analysis of a transmission electron microscope (TEM) or a scanning electron microscope (SEM). The average primary particle diameter of the filler contained in the optical film may be the average primary particle diameter of the filler used as a raw material, or may be the average primary particle diameter measured from the optical film. In the case of measuring the average primary particle diameter of the filler from the optical film, the average primary particle diameter of the filler in the optical film may be measured by image analysis of a transmission electron microscope or a scanning electron microscope using the film as a measurement sample. If necessary, the pulverized and crushed film is dissolved in a solvent capable of dissolving the resin in the film (for example, γ-butyrolactone), and the dispersed particles are transferred to a transmission electron microscope (TEM) or a scanning electron microscope ( SEM) may be observed and measured, or the filler may be taken out from the film, dried, and the average primary particle diameter may be calculated from the BET specific surface area in the same manner as above. When the average primary particle is measured by, for example, image analysis of an electron microscope, the average value of the result of measuring the primary particle diameter for each of 100 particles existing in a predetermined area may be used as the average primary particle diameter.

The content of the filler is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 5% by mass or more, more preferably 10% by mass or more, further preferably, based on the mass of the optical film. Is 15 mass% or more, more preferably 20 mass% or more, more preferably 25 mass% or more, particularly preferably 30 mass% or more. When the content of the filler is more than the above lower limit, it is easy to improve the impact resistance and durability of the optical film. The content of the filler is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 45% by mass or less based on the mass of the optical film. When the content of the filler is less than or equal to the above upper limit, the haze and yellowness of the optical film are easily reduced, transparency and optical properties are easily improved, and bending resistance is easily improved.

<Ultraviolet absorber>

The optical laminate of the present invention may contain at least one type of ultraviolet absorber. The ultraviolet absorber can be appropriately selected from those commonly used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light with a wavelength of 400 nm or less. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone compounds, salicylate compounds, benzotriazole compounds, and triazine compounds. The ultraviolet absorber may be used alone or in combination of two or more. When the optical film contains an ultraviolet absorber, deterioration of the resin is suppressed, and thus visibility can be improved when the optical film of the present invention is applied to an image display device or the like. In this specification, the "system compound" refers to a derivative of the compound to which the "system compound" is added. For example, the "benzophenone-based compound" refers to a compound having benzophenone as a parent skeleton and a substituent bonded to the benzophenone.

In the optical laminate of the present invention, when the optical film contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, more preferably 1, based on the mass of the resin contained in the optical film. It is -8 mass parts, More preferably, it is 2-7 mass parts. When the content of the ultraviolet absorber is more than the above lower limit, it is easy to improve ultraviolet absorbance. When the content of the ultraviolet absorber is less than or equal to the above upper limit, decomposition of the ultraviolet absorber due to heat during the production of the substrate can be suppressed, it is easy to improve optical properties, and for example, it is easy to reduce haze.

<Other additives>

The optical layered product of the present invention may further contain other additives other than a filler and an ultraviolet absorber. As other additives, for example, antioxidants, release agents, stabilizers, coloring agents such as bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, and leveling agents. When other additives are contained, the content may be preferably 0.005 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, and still more preferably 0.1 to 10 parts by mass, based on the mass of the optical film.

<Functional layer>

The optical laminated body of the present invention has an optical film and a functional layer laminated on at least one side of the optical film. The function of the functional layer is not particularly limited, and a hard coating function, an antistatic function, an anti-glare function, a low reflection function, an antireflection function, an antifouling function, a gas barrier function, a primer function, an electromagnetic wave shielding function, an undercoat function, and an ultraviolet absorption function. It may be a general function employed in an optical film such as a function, an adhesion function, and a color adjustment function. The functional layer may be a layer having one type of function or a layer having two or more types of functions. From the viewpoint of easy use as a front plate of a flexible display device, at least one of the functional layers is at least one selected from the group consisting of a hard coating function, an antistatic function, an antiglare function, a low reflection function, an antireflection function, and an antifouling function. It is preferable that it is a layer having a function of. The functional layer may have a plurality of functions as one layer, or two or more layers having each function may be laminated. When two or more layers are laminated, the order of lamination is appropriately set according to the function. These layers are laminated on one side or both sides of the optical film. In the case of lamination on both sides, the thickness, function, and order of lamination of the layers laminated on each side may be the same or different.

The thickness of the functional layer may be appropriately set depending on the intended function, but from the viewpoint of lightening the weight of the optical laminate and enhancing optical homogeneity, it is preferably 20 μm or less, more preferably 15 μm or less, and more preferably It is 10 μm or less.

(Hard coating function)

The hard coating function is a function of protecting the optical film by imparting scratch resistance and chemical resistance to the surface of the optical film. In the optical laminate of the present invention, the functional layer may be a layer having a hard coating function (hard coating layer). As the hard coating layer, a known hard coating layer may be appropriately employed, and for example, a known hard coating layer such as acrylic, epoxy, urethane, benzyl chloride, and vinyl may be mentioned. Among these, from the viewpoint of suppressing the decrease in visibility in the wide-angle direction of the optical layered product and improving the bending resistance, an acrylic-based, urethane-based, and a hard coating layer of a combination thereof is preferable. For example, the hard coating layer may be a cured product of a composition containing an active energy ray-curable compound. The active energy ray-curable compound is a compound having a property that is cured by irradiating an active energy ray such as an electron beam or an ultraviolet ray. As such an active energy ray-curable compound, an electron beam-curable compound cured by irradiating an electron beam, an ultraviolet-curable compound cured by irradiation with ultraviolet rays, etc. are mentioned, for example. These compounds are compounds similar to the main components of the hard coating agent used for formation of a normal hard coating layer, and examples thereof include (meth)acrylic resins. In particular, among (meth)acrylic resins, it is preferable to use a polyfunctional (meth)acrylate-based compound as a main component. In addition, in this specification, (meth)acrylic means acrylic and/or methacrylic, and (meth)acrylate means an acrylate and/or methacrylate.

The polyfunctional (meth)acrylate-based compound is a compound having at least two acryloyloxy groups and/or methacryloyloxy groups in a molecule, and specifically, ethylene glycol di (meth) acrylate, diethylene glycol di (Meth)acrylate, 1,6-hexanedioldi(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetra Methylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerin tri (Meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tris((meth)acrylate )Acryloyloxyethyl)isocyanurate, a phosphazene-based acrylate compound or a phosphazene-based methacrylate compound in which a (meth)acryloyloxy group is introduced into the phosphazene ring of the phosphazene compound, at least two A urethane (meth)acrylate compound obtained by reaction of a polyisocyanate having an isocyanate group with a polyol compound having at least one (meth)acryloyloxy group and a hydroxyl group, at least two carboxylic acid halides and at least one ( A polyester (meth)acrylate compound obtained by reaction with a polyol compound having a meth)acryloyloxy group and a hydroxyl group, and oligomers such as dimers and trimers of each of the above compounds may be mentioned.

These compounds may be used alone or in combination of two or more. Further, in addition to the polyfunctional (meth)acrylate compound described above, at least one monofunctional (meth)acrylate may be used. As monofunctional (meth)acrylate, for example, hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylic Rate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycidyl (meth)acrylate, and the like. These compounds are used alone or in combination of two or more. The content of the monofunctional (meth)acrylate compound is preferably 10% by mass or less with respect to the solid content of the compound contained in the composition for forming a functional layer (coating material for a hard coat layer). In addition, in this specification, the solid content means all components except a solvent contained in a curable composition.

To the functional layer, for example, for the purpose of adjusting the hardness, a polymerizable oligomer may be added. Examples of such oligomers include terminal (meth)acrylate polymethyl methacrylate, terminal styryl poly (meth)acrylate, terminal (meth)acrylate polystyrene, terminal (meth)acrylate polyethylene glycol, terminal (meth)acrylate Macromonomers, such as an acrylonitrile-styrene copolymer and a terminal (meth)acrylate styrene-methyl (meth)acrylate copolymer, are mentioned. When adding a polymerizable oligomer, the content is preferably 5 to 50% by mass based on the solid content of the composition for forming a functional layer.

The active energy ray-curable compound may be used in the form of a solution mixed with a solvent. The active energy ray-curable compound and its solution may be commercially available as a hard coating agent. As a commercially available hard coating agent, specifically, "NK hard M101" (manufactured by Shin-Nakamura Chemical Co., Ltd., urethane acrylate compound), "NK ester A-TMM-3L" (manufactured by Shin-Nakamura Chemical Corporation, tetramethyl Olmethane triacrylate), ``NK ester A-9530'' (manufactured by Shin-Nakamura Chemical Co., Ltd., dipentaerythritol hexaacrylate), ``KAYARAD (registered trademark) DPCA series'' (manufactured by Nippon Kayaku Corporation, D Derivatives of pentaerythritol hexaacrylate compound), ``Aronix (registered trademark) M-8560'' (manufactured by Toagosei Co., Ltd., polyester acrylate compound), ``New Frontier (registered trademark) TEICA'' (Daiichi Industries Pharmaceutical Co., Ltd.) Co., Ltd. product, tris (acryloyloxyethyl) isocyanurate), "PPZ" (Kyoei Chemical Co., Ltd. product, a phosphazene methacrylate compound) etc. are illustrated.

The thickness of the hard coating layer can be appropriately set, but from the viewpoint of bending resistance, surface hardness and optical homogeneity of the optical laminate, it is preferably 20 µm or less, more preferably 15 µm or less, further preferably 10 µm or less. .

As a method of laminating the hard coating layer on at least one side of the optical film, for example, a composition for forming a hard coating layer containing an active energy ray-curable compound (active energy ray-curable resin) is applied to the surface of a substrate (optical film) to activate Just irradiate energy rays. Such a composition can be obtained by mixing an active energy ray-curable compound as necessary with an additive or the like. The cured product of the composition for forming a hard coating layer constitutes a hard coating layer.

The composition for forming a hard coat layer preferably contains a solvent, and in the composition for forming a hard coat layer, the active energy ray-curable compound is preferably diluted with a solvent. In this case, the composition may be prepared by mixing an active energy ray-curable compound with various additives (for example, silicone oil, etc.) for imparting surface smoothness, and then diluting the obtained mixture with a solvent, or an active energy ray-curable compound May be prepared by diluting with a solvent and then mixing an additive, or may be prepared by mixing an active energy ray-curable compound and an additive previously diluted with a solvent, or an active energy ray-curable compound previously diluted with a solvent and an additive previously diluted with a solvent You may mix and manufacture. The composition after mixing may be further stirred.

Also from the viewpoint of facilitating application, it is preferable that the composition for forming a hard coating layer contains a suitable solvent. Examples of the solvent include aliphatic hydrocarbons such as hexane and octane, aromatic hydrocarbons such as toluene and xylene, alcohols such as ethanol, 1-propanol, isopropanol, and 1-butanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, It can be suitably selected and used from esters such as butyl acetate and cellosolves. You may mix and use several types of these organic solvents as needed. From the viewpoint of easy evaporation of the organic solvent by heating the composition for forming a hard coat layer after coating, the boiling point of the solvent is preferably in the range of 70°C to 200°C. The type or amount of the solvent is appropriately selected depending on the type or amount of the active energy ray-curable compound to be used, the material and shape of the substrate (optical film), the application method, the thickness of the target hard coat layer, and the like.

The temperature (T1) at which the composition for forming a hard coat layer is applied and then dried by heating is preferably ±30°C, more preferably ±20°C with respect to the boiling point (T2) of the solvent contained in the composition. When T1 is in the above range, there is a tendency that it is difficult to remain in the hard coating layer from which the solvent is obtained, and adhesion is difficult to decrease.

The solid content of the composition for forming a hard coating is preferably 5 to 60% by mass, more preferably 10 to 55% by mass, still more preferably 20 to 50% by mass, and even more preferably 25 to 50% by mass. When the solid content is in the above range, the film thickness to be coated is not too thick and the value of the equation (1) is not too large, so that the visibility is improved, and the surface smoothness of the resulting hard coating layer tends to be improved.

The composition for hard coating layer formation may contain a polymerization initiator. When ultraviolet rays or visible rays are used as active energy rays, a photopolymerization initiator is usually used as a polymerization initiator.

As a photoinitiator, for example, acetophenone, acetophenone benzyl ketal, anthraquinone, 1-(4-isopropylphenyl-2-hydroxy-2-methylpropan-1-one, carbazole, xanthone, 4-chloro Benzophenone, 4,4'-diaminobenzophenone, 1,1-dimethoxydioxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2,2-dimethoxy-2 -Phenylacetophenone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino Propan-1-one, triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one , Fluorenone, fluorene, benzaldehyde, benzoin ethyl ether, benzoisopropyl ether, benzophenone, Michler's ketone, 3-methylacetophenone, 3,3',4,4'-tetra tert-butylperoxycarbonyl Benzophenone (BTTB), 2-(dimethylamino)-1-[4-(morpholinyl)phenyl]-2-phenylmethyl)-1-butanone, 4-benzoyl-4'-methyldiphenylsulfide, benzyl And the like. Moreover, a photoinitiator may be used in combination with a dye sensitizer. Examples of the dye sensitizer include xanthene, thioxanthene, coumarin, ketocoumarin, and the like. Examples of the combination of the photopolymerization initiator and the dye sensitizer include a combination of BTTB and xanthene, a combination of BTTB and thioxanthene, a combination of BTTB and coumarin, and a combination of BTTB and ketocoumarin. have.

When a photoinitiator is used, the amount used is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the active energy ray-curable compound. If the amount is in the above range, there is a tendency that a sufficient curing rate is easily obtained. In addition, the amount of the photopolymerization initiator used is per 100 parts by mass of the active energy ray-curable compound, preferably 10 parts by mass or less.

The composition for forming a hard coat layer may contain an antistatic agent in addition to the active energy ray-curable compound. When the composition contains an antistatic agent, it is possible to impart an antistatic function to the hard coating layer. Examples of the antistatic agent include surfactants, conductive polymers, conductive particles, alkali metal salts and/or organic cation-anion salts. These antistatic agents are used either individually or in combination of two or more.

Examples of the surfactant include hydrocarbon-based surfactants, fluorine-based surfactants, and silicone-based surfactants.

Examples of the conductive polymer include polyaniline, polypyrrole, polyacetylene, and polythiophene.

Examples of the conductive particles include particles such as indium-tin-composite oxide (ITO) and antimony-doped tin oxide.

Examples of the alkali metal salt include organic salts and inorganic salts of alkali metals. Examples of the alkali metal ions constituting the cation portion of the alkali metal salt include lithium, sodium, and potassium ions. Among these alkali metal ions, lithium ions are preferred.

The anionic portion of the alkali metal salt may be composed of an organic substance or an inorganic substance. As no moiety constituting the organic salts, for ^{_{example, CH 3 COO -, CF 3}} COO -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 3 C -, C 4 F 9 SO ^{_{3 -, C 3 F 7 COO}} -, (CF 3 SO 2) (CF 3 CO) N -, (FSO 2) 2 N -, - O 3 S (CF 2) 3 SO 3 -, CO 3 2-, Equation (A1) to Equation (A4),

_{(A1): 2 N (C} n F 2n + 1 SO 2) - (n is an integer of 1-10),

_{(A2): CF 2 (C} m F 2m SO 2) 2 N - (m is an integer of 1-10),

_{^{(A3): - O 3 S}} (CF 2) l SO 3 - (l is an integer of 1-10),

_{(A4): (C p F} 2p + 1 SO 2) N - (C q F 2q + 1 SO 2), ( single, p and q are, independently of each other, an integer of 1-10),

The anion part indicated by is used. In particular, the anionic moiety containing a fluorine atom is preferably used from the viewpoint of obtaining an ionic compound having good ion dissociation properties. As no moiety constituting the inorganic ^{salts, Cl -, Br -, I} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, AsF 6 -, SbF 6 _{^{-, NbF 6 -, TaF 6}} -, (CN) 2 N - or the like is used. No Examples ^{_{moiety, (FSO 2) 2 N -}} , (CF 3 O 2) 2 N -, (C 2 F 5 SO 2) 2 N - is preferable, and ^{_{(FSO 2) 2 N -,}} (CF 3 SO 2 ) ₂ N ^- is more preferable.

The organic cation-anion salt is composed of a cation moiety and an anion moiety, and is an organic salt in which the cation moiety is an organic substance. The anionic moiety may be an organic material or an inorganic material. The "organic cation-anion salt" may be a substance referred to as an ionic liquid or an ionic solid.

As a cation component, specifically, pyridinium cation, piperidinium cation, pyrrolidinium cation, cation having a pyrroline skeleton, cation having a pyrrole skeleton, imidazolium cation, tetrahydropyrrole Midinium cation, dihydropyrimidinium cation, pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, and the like. Examples of the anionic component include those similar to the anion moiety of the alkali metal salt. Among them, an anionic component containing a fluorine atom is preferably used from the viewpoint of obtaining an ionic compound having good ion dissociation properties.

The composition for forming a hard coat layer is an organic compound containing, for example, a bromine atom, a fluorine atom, a sulfur atom, a benzene ring, etc., such as tin oxide, antimony oxide, titanium oxide, zirconium oxide, zinc oxide, silicon oxide, etc. You may contain inorganic oxide fine particles or the like. In this case, the refractive index of the obtained hard coating layer can be adjusted, and optical functions such as a low reflection function and an antireflection function can be provided to the hard coating layer.

A layer containing an active energy ray-curable compound can be formed by applying the composition for forming a hard coat layer containing an active energy ray-curable compound on the optical film and then drying it. Coating can be performed by a conventional method such as a microgravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a cast transfer method, a flow coating method, and a spray coating method. From the viewpoint of easy to increase the optical homogeneity of the optical laminate, it is preferable to laminate the composition for forming a hard coat layer by a microgravure coating method or a die coating method.

Thereafter, by irradiating an active energy ray, the active energy ray-curable compound coated on the surface of the optical film is cured to obtain a target hard coating layer. Examples of the active energy ray include electron beams, ultraviolet rays, visible rays, and the like, and are appropriately selected according to the kind of the active energy ray-curable compound to be used. The active energy ray may be irradiated in the same manner as in the formation of an ordinary hard coat layer. The intensity, irradiation time, and the like of the active energy ray to be irradiated are appropriately selected depending on the type of the curable compound to be used, the thickness of the layer containing the curable compound, and the like. The active energy ray may be irradiated in an inert gas atmosphere. In order to irradiate an active energy ray in a nitrogen atmosphere, for example, an active energy ray irradiation may be performed in a container sealed with an inert gas, and nitrogen gas, argon gas, or the like can be used as the inert gas.

It is also useful to further laminate an antireflection layer or a low reflection layer described later on the surface of the hard coating layer. In this case, the antireflection layer or the low reflection layer can be laminated on the surface of the hard coating layer as a single layer or as a multilayer.

(Antistatic function)

The antistatic function is a function of preventing the surface of the optical film from being charged. In the optical laminate of the present invention, the functional layer may be a layer having an antistatic function (antistatic layer). As a method of forming the antistatic layer, in addition to the method of imparting an antistatic function to the hard coat layer by adding an antistatic agent to the composition for forming the hard coat layer, a composition for forming an antistatic layer obtained by diluting an antistatic agent with a solvent, etc. Alternatively, a method of coating on the functional layer laminated on the optical film, drying as necessary, and forming as a single film may be mentioned. The antistatic agent may be included as a structural unit having an antistatic function in a part of the resin constituting the functional layer (for example, a cured product of the active energy ray-curable compound described above), and in the resin forming the functional layer And may be added as an additive. When an antistatic agent is added as an additive, the amount added is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, more preferably 0.1 to 10% by mass, based on the solid content of the composition for forming a functional layer. It is mass%.

(Anti-glare function)

The anti-glare function is a function of preventing reflection of external light by scattering and reflecting light. In the optical laminate of the present invention, the functional layer may be a layer having an anti-glare function (anti-glare layer). As the antiglare layer, a known one can be appropriately adopted. For example, an anti-glare function may be imparted by forming a layer having a fine uneven shape on the surface using a resin composition containing one or more types of light-transmitting fine particles in the light-transmitting resin. More specifically, such an anti-glare layer is applied such that, for example, a translucent resin solution in which translucent fine particles as a filler are dispersed is applied onto the optical film, and the translucent fine particles become a convex portion on the surface of the anti-glare layer. It can be formed by adjusting the thickness. In addition, in this specification, "translucent" means that light can substantially transmit regardless of the presence or absence of scattering inside a substance.

Translucent fine particles

Examples of the light-transmitting fine particles include organic fine particles such as (meth)acrylic resin, melamine resin, polyethylene resin, polystyrene resin, polycarbonate resin, vinyl chloride resin, organic silicone resin, acrylic-styrene copolymer, and calcium carbonate, Inorganic fine particles, such as silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, and glass, are mentioned. As the translucent fine particles, one or two or more types of fine particles can be used. In order to obtain a desired anti-glare property, the kind, particle diameter, refractive index, content, etc. of the translucent fine particles are appropriately adjusted.

The particle diameter of the translucent fine particles is preferably 0.5 to 5 µm, more preferably 1 to 4 µm. When the particle diameter of the translucent fine particles is within the above range, a necessary light diffusion effect is easily obtained, and since irregularities are easily formed on the surface of the antiglare layer, a sufficient antiglare effect is easily obtained. In addition, there is a tendency that the surface shape of the anti-glare layer is not rough and the haze value does not increase significantly.

The difference in the refractive index between the translucent fine particles and the translucent resin is preferably 0.02 to 0.2, more preferably 0.04 to 0.1. When the refractive index difference is within the above range, it is easy to obtain a sufficient light diffusion effect, and it is difficult to whiten the entire optical laminate.

The amount of the translucent fine particles added is preferably 3 to 30 parts by mass, more preferably 5 to 20 parts by mass, based on 100 parts by mass of the translucent resin. When the addition amount is within the above range, it is easy to obtain a sufficient light diffusion effect, and it is difficult to whiten the entire optical laminate.

When adjusting the particle diameter, the amount of the translucent fine particles, and/or the difference in refractive index between the translucent fine particles and the translucent resin in the above range, even in the region where the haze of the anti-glare layer is high, the transmittance clarity is not reduced, and glare on the surface is reduced It is easy to prevent, and furthermore, even in a low haze area, it is easy to prevent glare while maintaining high transmission and sharpness.

Translucent resin

The light-transmitting resin constituting the anti-glare layer is not particularly limited as long as it has light-transmitting properties, and examples thereof include a cured product of a thermosetting resin other than the cured product of the active energy ray-curable compound as described above; Thermoplastic resin; And metal alkoxide-based polymers. Among them, a cured product of an active energy ray-curable compound is preferable. When an ultraviolet curable resin or the like is used as the active energy ray-curable compound, similarly to the above, a photopolymerization initiator (radical polymerization initiator) may be contained in the coating liquid, and the coating layer is cured by irradiating with an active energy ray.

As a thermosetting resin, a thermosetting urethane resin, a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, a silicone resin, etc. which consist of an acrylic polyol and an isocyanate prepolymer are mentioned.

Examples of the thermoplastic resin include cellulose derivatives such as acetyl cellulose, nitro cellulose, acetyl butyl cellulose, ethyl cellulose, and methyl cellulose; Vinyl resins such as vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, and vinylidene chloride and copolymers thereof; Acetal resins such as polyvinyl formal and polyvinyl butyral; (Meth)acrylic resins such as acrylic resins and copolymers thereof, methacrylic resins and copolymers thereof; Polystyrene resin; Polyamide resin; Polyester resin; And polycarbonate resins.

As the metal alkoxide-based polymer, a silicon oxide-based matrix using a silicon alkoxide-based material as a raw material can be used. Specifically, the metal alkoxide polymer may be an inorganic or organic-inorganic composite matrix obtained by dehydrating and condensing a hydrolyzate of an alkoxysilane such as tetramethoxysilane or tetraethoxysilane.

In the case of using a cured product of a thermosetting resin or a metal alkoxide polymer as the translucent resin, heating may be required after coating a coating solution.

Further, in general, the refractive index of the ultraviolet curable resin is about 1.5, which is about the same as that of glass, but in comparison with the refractive index of the translucent fine particles, the refractive index of the ultraviolet curable resin to be used may be low. In this case, in the translucent resin, TiO ₂ (refractive index; 2.3-2.7), Y ₂ O ₃ (refractive index; 1.87), La ₂ O ₃ (refractive index; 1.95), ZrO ₂ (refractive index; 2.05), which are fine particles having a high refractive index, Al ₂ O ₃ (refractive index; 1.63) or the like is added to the extent that the diffusivity of light in the anti-glare layer can be maintained, and the refractive index of the transmissive resin can be increased and adjusted to a preferable range.

The composition for forming an antiglare layer can be produced by dispersing light-transmitting fine particles in a composition containing a light-transmitting resin and a solvent (for example, the composition for forming a hard coat layer). The timing and dispersion method for dispersing the translucent fine particles are not particularly limited.

The anti-glare layer can be formed by applying and drying the composition (coating liquid) for forming an anti-glare layer on the surface of the optical film or the surface of the functional layer laminated on the optical film. Coating can be performed by a conventional method, for example, a microgravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a cast transfer method, a flow coating method, and a spray coating method. . After that, the ultraviolet curable resin may be cured by irradiating ultraviolet rays. The intensity of the ultraviolet rays to be irradiated, the irradiation time, and the like are appropriately selected depending on the kind of curable compound to be used, the thickness of the layer containing the curable compound, and the like. Ultraviolet rays may be irradiated in an inert gas atmosphere. In order to irradiate ultraviolet rays in an inert gas atmosphere, for example, active energy ray irradiation may be performed in a container sealed with an inert gas, and nitrogen gas, argon gas, or the like can be used as the inert gas.

As another method of forming the anti-glare layer, an embossing treatment can be used. In this method, after coating the composition for forming an antiglare layer on the optical film or the functional layer laminated on the optical film, the coating layer is formed as necessary while pressing a mold (embossing roll) having a predetermined surface uneven shape on the coating layer. By hardening, it is possible to impart unevenness to the surface of the coating layer. After peeling the anti-glare layer from the embossing roll, for the purpose of further accelerating the curing reaction of the anti-glare layer, it is also effective to perform a second curing step in which ultraviolet rays are once again irradiated from the anti-glare layer side.

The haze of the anti-glare layer is preferably 0.1 to 50%. The haze of the anti-glare layer is measured by a method conforming to JIS K 7361. The thickness of the anti-glare layer may be appropriately adjusted so that, for example, the haze of the anti-glare layer falls within the above range, but is preferably 2 to 20 µm. If the thickness of the anti-glare layer is within the above range, a sufficient anti-glare effect is easily obtained, it is easy to prevent cracking of the anti-glare layer, and the productivity is lowered by the anti-glare layer curling due to curing shrinkage of the anti-glare layer. Easy to prevent. In addition, the thickness of the anti-glare layer is generally 85% or more, more preferably 100% or more with respect to the weight average particle diameter of the translucent fine particles to be dispersed. When the thickness of the anti-glare layer is within the above range, there is a tendency that the haze is not too large and the visibility is difficult to decrease.

The anti-glare layer may contain an antistatic agent. By containing an antistatic agent, an antiglare layer having an antistatic function can be obtained. As an antistatic agent, the thing similar to the antistatic agent added to the hard coat layer mentioned above is mentioned.

The antiglare layer may have a low reflection layer on the outermost surface, that is, on the side of the uneven surface. Even in the absence of a low-reflective layer, a sufficient anti-glare function is exhibited, but by providing a low-reflective layer on the outermost surface, the anti-glare property can be further improved. As the low reflection layer, what was described later can be applied.

(Anti-reflection function and low-reflection function)

The antireflection function and the low reflection function are functions of preventing or reducing reflection of external light. In the optical laminate of the present invention, the functional layer may be a layer having a function of preventing reflection of external light (antireflection layer), or a layer having a function of reducing reflection of external light (low reflection layer). The antireflection layer and the low reflection layer may be a single layer or a multilayer.

Antireflection layer

The antireflection layer may have a low refractive index layer. Further, the antireflection layer may be a layer having a multilayer structure further comprising a low refractive index layer and a high refractive index layer and/or a medium refractive index layer laminated between the low refractive index layer and the optical film. You may provide the hard coating layer described above between the antireflection layer and the optical film.

The thickness of the antireflection layer is preferably 0.01 to 1 µm, more preferably 0.02 to 0.5 µm. Examples of the antireflection layer include a low refractive index layer having a refractive index smaller than that of the optical film or functional layer on which the antireflection layer is laminated (for example, a refractive index of 1.3 to 1.45); A layer in which a plurality of low refractive index layers of a thin film made of inorganic compounds and high refractive index layers of a thin film made of inorganic compounds are alternately stacked may be mentioned. Here, the refractive index of the high refractive index layer may be greater than the refractive index of the low refractive index layer, but is preferably 1.60 or more.

The material for forming the low refractive index layer is not particularly limited as long as it is a material having a low refractive index. For example, a resin material such as an active energy ray-curable resin (for example, an ultraviolet-curable acrylic resin), a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, and a sol using a metal alkoxide such as tetraethoxysilane -Gel materials, etc. are mentioned. The material for forming these low refractive index layers may be polymers that have been polymerized, or may be monomers or oligomers that become precursors. In addition, since the material constituting the antireflection layer can impart an antifouling function to the antireflection layer, it is preferable to contain a compound containing fluorine.

The high refractive index layer is coated with a coating solution containing a light-transmitting resin such as a cured product of the above-described active energy ray-curable resin or a metal alkoxide-based polymer, and inorganic fine particles and/or organic fine particles, and then cured the coating layer as necessary. It can be formed by a method to make. Examples of the inorganic fine particles include zinc oxide, titanium oxide, cerium oxide, aluminum oxide, silane oxide, tantalum oxide, yttrium oxide, ytterbium oxide, zirconium oxide, antimony oxide, and indium tin oxide (ITO). The high refractive index layer containing these inorganic fine particles can also have an antistatic function.

As a method of manufacturing a multilayer film in which a transparent thin film of inorganic compounds (metal oxides, etc.) having different refractive indices is stacked, it is a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, a sol/gel method of metal compounds such as metal alkoxides After forming the colloidal metal oxide particle film, a method of forming a thin film by post-treatment (ultraviolet irradiation: Japanese Unexamined Patent Application Publication No. Hei 9-157855, plasma treatment: Japanese Unexamined Patent Application Publication No. 2002-327310), etc. are mentioned. .

On the other hand, it is also preferable to laminate an antireflection layer by laminating a thin film in which inorganic particles are dispersed in a matrix from the viewpoint of easy productivity improvement. Further, it is also possible to further impart an anti-glare function to the anti-reflection layer by forming a fine uneven shape on the coated surface when the anti-reflection layer is laminated by coating the composition for forming an anti-reflection layer in which inorganic particles are dispersed in a matrix.

Low reflective layer

The low-reflective layer is a layer formed of a low-refractive-index material having a lower refractive index than an optical film serving as a base material. The low refractive index layer is formed by a method of curing the coating layer as necessary after coating a coating solution containing a light-transmitting resin such as a cured product of the active energy ray-curable resin or a metal alkoxide-based polymer and inorganic fine particles described above. can do. As such a low refractive index material, specifically, inorganic material fine particles such as _{lithium fluoride (LiF), magnesium fluoride (MgF 2} ), aluminum fluoride (AlF ₃ ), and cryolite (3NaF·AlF ₃ or Na ₃ AlF ₆₎ , An inorganic low-reflective material contained in an acrylic resin, an epoxy resin, or the like; Organic low-reflection materials, such as a fluorine-based or silicone-based organic compound, a thermoplastic resin, a thermosetting resin, and an ultraviolet curable resin, are mentioned.

(Antifouling function)

The antifouling function is a function of preventing contamination, and is a function obtained by imparting water repellency, oil repellency, cold resistance, stain resistance, anti-fingerprint, and the like to the layer. In the optical laminate of the present invention, the functional layer may be a layer having an antifouling function (antifouling layer). The material for forming the antifouling layer may be an organic compound or an inorganic compound. As a material that brings about high water repellency and oil repellency, a fluorine-containing organic compound, an organosilicon compound, etc. are mentioned. Examples of the fluorine-containing organic compound include fluorocarbons, perfluorosilanes, and these high molecular compounds. From the viewpoint of easily enhancing the effect of preventing contamination adhesion, a material such that the contact angle of the surface of the antifouling layer with pure water is 90 degrees or more, and furthermore 100 degrees or more is preferable. As a method of forming the antifouling layer, depending on the material to be formed, a physical vapor deposition method, a chemical vapor deposition method, a wet coating method, or the like can be used, using vapor deposition or sputtering as representative examples. The average thickness of the antifouling layer is usually about 1 to 50 nm, preferably 3 to 35 nm.

(Ultraviolet absorption function)

In the optical laminate of the present invention, the functional layer may be an ultraviolet absorbing layer having a function of absorbing ultraviolet rays. The ultraviolet absorbing layer is composed of a main material selected from, for example, an ultraviolet-curable light-transmitting resin, an electron beam-curable light-transmitting resin, and a thermosetting type light-transmitting resin, and an ultraviolet absorber dispersed in the main material.

(Adhesive function)

In the optical layered product of the present invention, the functional layer may be an adhesive layer having an adhesive function to adhere an optical film to another member. As the material for forming the adhesive layer, a commonly known material can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used. In this case, the thermosetting resin composition or the photocurable resin composition can be polymerized and cured by supplying energy afterwards.

The adhesive layer may be a layer that is attached to an object by pressure, called a pressure sensitive adhesive (PSA). The pressure-sensitive adhesive may be a pressure-sensitive adhesive that is "a substance that has adhesiveness at room temperature and adheres to an adherend with light pressure" (JIS K 6800), or "a specific component is contained in a protective film (microcapsule), An adhesive that can maintain stability until the film is destroyed by means (pressure, heat, etc.)" (JIS K 6800) may be a capsule adhesive.

(Color adjustment function)

In the optical laminate of the present invention, the functional layer may be a hue adjustment layer having a function of adjusting the optical laminate to a target hue. The hue adjustment layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, bengala, titanium oxide-based calcined pigments, ultramarine, cobalt aluminate, and carbon black; Organic pigments such as azo compounds, quinacridone compounds, anthraquinone compounds, perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, srene compounds, and diketopyrrolopyrrole compounds; Extender pigments such as barium sulfate and calcium carbonate; And dyes such as basic dyes, acid dyes, and mordant dyes.

<Method of manufacturing an optical laminate>

The method of manufacturing the optical laminate of the present invention having the above characteristics is not particularly limited, but, for example, the following steps:

(a) a process of applying a varnish containing at least a polyimide resin and/or a polyamide resin, and a solvent on a support and drying to form a coating film,

(b) the step of peeling the coating film from the support,

(c) heating the peeled coating film to obtain a film, and

(d) a step of laminating a functional layer on at least one side of the film to obtain an optical laminate

It can be manufactured by a manufacturing method containing at least. The present invention also provides a method for manufacturing an optical layered product including at least the above steps.

The manufacturing method of the optical layered product of the present invention is after the step (c) or after the step (d),

(e) Using the obtained film or optical laminate, the line profiles in the directions h and v perpendicular to each other in the film inverse space obtained by Fourier transforming the projection image obtained by the projection method are respectively a line profile h and a line profile. denoted by v, and a line profile in a direction h'and a direction v'that are orthogonal to each other in a background inverse space obtained by Fourier transform of a background image obtained without using the film or the optical laminate in the projection method, respectively The maximum intensity of the line profile (h-h') obtained by subtracting the line profile h'from the line profile h'and the line profile _v'is called Y mh, and the frequency representing the maximum intensity Y _{mh is X mh} Y _mh and Y when the maximum intensity of the line profile (v-v') obtained by subtracting the line profile v'from the line profile v is Y _mv , and the frequency representing the _{maximum intensity Y mv is X mv.} value of _mv, and, Y _{mh, mv} Y, X and X _mh (Y + Y _{mv mh)} which is calculated from the _mv / (X + X _{mv mh)} on the basis of the value of ^1/2, the step of evaluating the film

You may further include.

The varnish used in the above step (a) contains at least a polyimide resin and/or a polyamide resin and a solvent. Here, the viscosity (cps) of the varnish and the solid content concentration (% by mass) of the varnish are the following relationship:

It is desirable to meet.

First, a process (a) of applying a varnish on a support and drying it to form a coating film will be described. As the resin contained in the varnish, the resin described above as the resin contained in the optical film can be mentioned. Further, the varnish may contain the above-described ultraviolet absorber, filler, and other additives.

The solvent contained in the varnish is not particularly limited as long as the resin can be dissolved. Examples of such a solvent include amide solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide; lactone solvents such as γ-butyrolactone (GBL) and γ-valerolactone; Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; Carbonate-based solvents such as ethylene carbonate and propylene carbonate; And combinations thereof (mixed solvent). Among these, an amide-based solvent or a lactone-based solvent is preferable from the viewpoint of easily enhancing the optical homogeneity of the optical layered product. These solvents may be used alone or in combination of two or more. In addition, the varnish may contain water, an alcohol solvent, a ketone solvent, an acyclic ester solvent, an ether solvent, and the like. The solid content concentration of the varnish is preferably 1 to 25% by mass, more preferably 5 to 20% by mass.

The varnish can be prepared by mixing and stirring the resin, a solvent, and an ultraviolet absorber, filler, and other additives used as necessary. For example, the reaction solution of a polyimide resin or a polyamide resin obtained by reacting the above dicarboxylic acid compound, tetracarboxylic acid compound, and/or diamine compound, and other raw materials described above is used as a solvent and a case You may prepare a varnish by mixing and stirring together with other additives depending on. A varnish may be prepared by isolating a polyimide resin or polyamide resin from the reaction solution and mixing with a solvent, etc., or purchasing a solution or solid of a polyimide resin or polyamide resin, and mixing with a solvent, if necessary. By doing so, you may prepare a varnish. In the case of using silica as a filler, a dispersion of silica sol containing silica may be prepared by using a silica sol substituted with a solvent in which the resin is soluble, for example, a solvent used for preparing the following varnish. do.

The viscosity (cps) of the varnish prepared as described above and the solid content concentration (mass%) of the varnish are not particularly limited, but from the viewpoint of easy obtaining an optical laminate having excellent optical homogeneity, they have the following relationship:

It is desirable to meet. Here, the viscosity (cps) of the varnish is measured at 25°C using an E-type viscometer according to JIS K 8803:2011. In addition, the solid content concentration of the varnish represents the concentration (mass%) of resins, fillers, additives, etc. contained in the varnish, and is calculated from the mass of the solid content contained in the varnish based on the total mass of the varnish. The product of the viscosity of the varnish represented by the above formula and the solid content concentration of the varnish is preferably 3,000 or more, more preferably 3,500 or more, from the viewpoint of easy to increase the optical homogeneity of the optical laminate. The upper limit of the product of the viscosity of the varnish represented by the above formula and the solid content concentration of the varnish is not particularly limited, but from the viewpoint of handling of the varnish, it is preferably 10,000 or less, more preferably 7,000 or less.

The viscosity of the varnish is preferably 5,000 to 60,000 cps, more preferably 10,000 to 50,000 cps, and still more preferably 15,000 to 45,000 cps. When the viscosity of the varnish is more than the above lower limit, the effect of the present invention is easily obtained, and when it is less than the above upper limit, it is easy to improve the handling of the varnish.

The solid content concentration of the varnish is preferably 5 to 25% by mass, more preferably 10 to 23% by mass, and still more preferably 14 to 20% by mass. It is preferable from the viewpoint of obtaining a thick film that the solid content concentration of the varnish is more than the above lower limit, and from the viewpoint of easy handling of the varnish, it is preferable that it is less than the above upper limit.

Examples of the support include a resin substrate, a stainless steel belt, and a glass substrate. It is preferable to use a resin film base material as a support. Examples of the resin film substrate include a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a cycloolefin (COP) film, an acrylic film, a polyimide film, and a polyamideimide film. Among them, from the viewpoint of excellent smoothness and heat resistance, a PET film, a COP film, and the like are preferable, and a PET film is more preferable from the viewpoint of adhesion and cost with an optical film.

The thickness of the support is not particularly limited, but is preferably 50 to 250 µm, more preferably 100 to 200 µm, and still more preferably 125 to 200 µm. When the thickness of the support is less than or equal to the above upper limit, it is preferable because it is easy to suppress the production cost of the film. Further, it is preferable that the thickness of the support is more than the above lower limit because it is easy to suppress the curl of the film that may occur in the step of removing at least a part of the solvent. Here, the thickness of the support is measured by a contact-type film thickness meter or the like. From the viewpoint of easy to improve the surface quality of the optical laminate and easy to manufacture the optical laminate of the present invention, the thickness distribution of the support is preferably ± 3 μm or less, more preferably ± 2.5 μm or less, and more preferably Is less than ±2㎛. The thickness distribution of the support body is calculated from the difference between the thickness at each location and the average thickness by measuring the thickness at at least 20 locations of the film, calculating the average thickness at 20 locations, according to the method for measuring the thickness. .

When applying the varnish on the support, you may apply the varnish to the support by a known application method. Known coating methods include, for example, wire bar coating, reverse coating, roll coating such as gravure coating, die coating, comma coating, lip coating, spin coating, screen coating, fountain coating, di The ping method, the spray method, the casting method, etc. are mentioned.

Subsequently, the coating film can be formed by drying the coating film of the varnish applied on the support. Drying is performed by removing at least a part of the solvent from the coating film of the varnish, and the drying method is not particularly limited. For example, drying may be performed by heating the coating film of the varnish applied on the support. In the following, drying in step (a) is also referred to as "first drying", and the coating film formed on the support after drying is also referred to as "dry coating film". The dry coating film may be a coating film in which all of the solvents contained in the varnish are dried, or a semi-dried coating film in which a part of the solvent is dried. If necessary, the first drying may be performed under an inert atmosphere or under reduced pressure conditions. It is preferable to perform the first drying at a relatively low temperature over time. If the first drying is performed at a relatively low temperature over time, it is easy to lower the values _{of Y mh} and Y _{mv in the above equation, and the value of (Y mh} +Y _mv )/(X _mh +X _mv ) ^1/2 It is easy to decrease the value, and it is easy to increase the optical homogeneity of the optical laminate.

In particular, when the optical laminate of the present invention is industrially manufactured, the actual manufacturing environment is often disadvantageous in improving optical homogeneity compared to the manufacturing environment at the laboratory level. As a result, the optical homogeneity of the optical laminate It may be difficult to increase the value. It is as described above that it is preferable to perform the first drying at a relatively low temperature over time, but at the laboratory level, when the first drying is performed, the drying can be performed in a sealed dryer, so optical lamination due to external factors The roughness of the surface of the sieve is relatively difficult to occur. On the other hand, in the case of industrially manufacturing an optical laminate, for example, since it is necessary to heat a large area in the first drying, a blowing device may be used during heating. As a result, the surface state of the optical film tends to become rough, and it is difficult to improve the optical homogeneity of the film.

In the case of drying by heating, especially considering the external factors as described above when manufacturing an optical laminate industrially, the heating temperature at the time of the first drying is preferably 60 to 150°C, more preferably It is 60-130 degreeC, More preferably, it is 70-120 degreeC. The first drying time is preferably 5 to 60 minutes, more preferably 10 to 40 minutes. The first drying may be carried out under conditions of one step or multiple steps, but it is preferable to carry out under three or more heating temperature conditions, especially considering the external factors as described above when industrially manufacturing an optical laminate. When drying is performed under the conditions of multiple stages, preferably, in each stage, drying can be performed under the same or different temperature conditions and/or drying time, for example, 3 to 10 steps, preferably 3 to Drying may be performed under the conditions of eight steps. When the first drying is performed under conditions of multiple stages, it is easy to increase the optical homogeneity of the optical laminate. In a preferred embodiment of the present invention in which the first drying is performed under three or more multi-stage conditions, it is preferable that the temperature profile of the first drying includes an increase in temperature and a decrease in temperature. That is, it is more preferable that the drying conditions in the step (a) are three or more heating temperature conditions in which the temperature profile includes temperature rise and fall. As such a temperature profile, for example in the case of four stages, the temperature of the first drying is, in turn, 70 to 90°C (first temperature), 90 to 120°C (second temperature), and 80 to 120°C (third temperature) ) And 80-100° C. (fourth temperature). In this example, the temperature of the first drying is raised from the first temperature to the second temperature, then the temperature is lowered from the second temperature to the third temperature, and the temperature is lowered from the third temperature to the fourth temperature. Here, the time of the first drying is, for example, 5 to 15 minutes in each step. It is preferable to perform the first drying so that the residual amount of the solvent in the dry coating film is preferably 5 to 15 mass%, more preferably 6 to 12 mass% with respect to the mass of the dry coating film. When the residual amount of the solvent is within the above range, it is easy to decrease the values _{of Y mh} and Y _{mv in the above formulas of the optical film or optical laminate, and (Y mh} +Y _mv )/(X _mh +X _mv ) ^{1/ It is} easy to decrease the value of 2. Moreover, it is easy to improve the peelability when peeling the coating film from a support body in successive step (b). As a result, it is easy to increase the optical homogeneity of the optical laminate. The residual amount of the solvent decreases by increasing the drying temperature of each step and lengthening the drying time. For this reason, it is possible to improve the optical homogeneity of the optical laminate by adjusting the drying temperature and the drying time so that the remaining amount of the solvent within a desired range.

Next, in the step (b), the dried coating film is peeled from the support. The peeling method is not particularly limited, and peeling may be performed by moving the coating film while the support is fixed, or peeling may be performed by moving the support while the coating film is fixed, and peeling is performed by moving both the coating film and the support. You may do it.

Next, in the step (c), an optical film can be obtained by heating the coating film peeled off in the step (b). The heating step in the step (c) is also referred to as "second drying" or "post bake" below, and the coating film peeled off in the step (b) is also referred to as a "peel coating film" below. In step (c), it is preferable to perform post-baking in a state where the peeling coating film is stretched in the in-plane direction. The heating temperature at the time of the second drying is preferably 150 to 300°C, more preferably 180 to 250°C, and still more preferably 180 to 230°C. The heating time in 2nd drying becomes like this. Preferably it is 10 to 60 minutes, More preferably, it is 30 to 50 minutes. If post-baking treatment is performed in a state where the dry coating film is uniformly stretched in the in-plane direction, _{the values of Y mh} and Y _mv in the above formulas of the optical film or optical laminate are likely to be reduced, (Y _mh + Y _mv )/(X _mh +X _mv ) It is easy to decrease the value of ^1/2.

When heating the coating film in step (3), it is preferable to heat the coating film in a state in which tension is applied to the coating film and the coating film is stretched in the in-plane direction. By heating while applying tension, it is easy to suppress the decrease in optical homogeneity of the film caused by shrinkage of the coating film due to drying, and as a result, Y _mh and Y _mv in the above equations of the optical film or optical laminate It is easy to decrease the value, it is easy to decrease the value of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 , and it is easy to increase optical homogeneity.

In one embodiment of the present invention, when producing an optical film by a roll-to-roll method, you may dry the peeling coating film in a state stretched in the conveyance direction. Further, in the case of manufacturing an optical film in a single wafer type, it may be dried in a state uniformly elongated in the in-plane direction. The conveyance speed in the roll-to-roll system is preferably 0.1 to 10 m/min, more preferably 0.5 to 8 m/min, and still more preferably 0.5 to 10 m/min, from the viewpoint of easy to increase the optical homogeneity of the optical laminate. It is 5m/min.

For example, in the case of manufacturing an optical film by a roll-to-roll method, an optical film can be obtained by heating while conveying a long strip-shaped coating film having a predetermined width. Here, in the case of heating while applying tension to the coating film, the method is not limited in any way, for example, while holding both ends of the long strip-shaped film to be conveyed, and conveying the gripped film, the gripped film is With the width being a predetermined distance, for example, heat treatment is performed while conveying the inside of the dryer. At this time, the ratio of the width of the film after heat treatment (however, the gripping part is not included in the width) to the width of the film before heat treatment (however, the gripping part is not included in the width) is 1.1 or less, and the dryer It is preferable to perform the process (3) by releasing the gripping of the resin film that has come out from.

The ratio of the width of the film after heat treatment (however, the gripping part is not included in the width) to the width of the film before heat treatment (however, the gripping part is not included in the width) (hereinafter sometimes referred to as a draw ratio) is , Preferably it is 0.70-1.10, More preferably, it is 0.80-1.05, More preferably, it is 0.85-1.03.

The holding of the film is performed, for example, by using a plurality of clips.

The plurality of clips may be fixed to an endless chain of a predetermined length according to the size of the conveying device, the chain moves at the same speed as the film, the clip is installed at an appropriate position of the chain, and the dryer The transparent resin film is gripped before entering, and the gripping is released at the point when the dryer is exited.

A plurality of clips installed at one end of the film is such that the space between the adjacent clips is, for example, 1 to 50 mm, preferably 3 to 25 mm, more preferably 5 to 10 mm. , Is installed.

In addition, when a straight line perpendicular to the film conveyance axis is aligned with the center of the gripping part of an arbitrary clip at one end of the film, the intersection of the straight line and the other end of the film, and the center of the gripping part of the clip closest to the intersection The distance can be made to be preferably 3 mm or less, more preferably 2 mm or less, and still more preferably 1 mm or less. When the distance is in the above range, it is easy to increase the homogeneity of the film in particular in the left and right.

When the ratio of the width of the film after heat treatment to the width of the film before heat treatment is in the above range, the film appearance tends to be good.

The amount of solvent in the film after heat treatment is based on the mass of the film, preferably 0.001 to 3% by mass, more preferably 0.001 to 2% by mass, still more preferably 0.001 to 1.5% by mass, particularly preferably 0.001 It is -1.3 mass%. When the amount of the solvent in the film after heat treatment is in the above range, the appearance of the optical film tends to be good.

When the heat treatment is finished and the film comes out of the dryer, the gripping of the film is released, preferably immediately, the end of the film is slit. By performing a slit, cracks that are likely to occur between the gripped portion and the portion that were not gripped at the end of the film are removed from the film, and the film is then conveyed to reduce the temperature of the film. You can prevent magnification in advance.

When the film comes out of the dryer, the film rapidly cools and shrinks, causing cracks in some cases. For this reason, it is preferable that there is a step of relaxing the film in a certain ratio from the outlet of the dryer to the position where the gripping of the film is released. The ratio is the width of the film from the dryer (excluding the gripped width) (W) and the distance (F) at which the gripping part is relaxed until the film is released from the dryer outlet, preferably 1.7≦F/ W×100≦6.9, more preferably 1.8≦F/W×100≦6.8, more preferably 1.9≦F/W×100≦6.7, and even more preferably 2.0≦F/W×100≦6.7.

With respect to the conveying direction of the film, the relaxation distance on one end side is called Fa, the relaxation distance on the other end side is called Fb, and the combined distance F is called relaxation.

The distance from the outlet of the dryer until the gripping of the film is released is preferably 200 to 2,000 mm, more preferably 300 to 1,500 mm, more preferably 300 to 1,300 mm, and even more preferably 300 to 1,000 mm. . If the distance is within the above range, there is a tendency that cracks are less likely to occur in the film, and appearance defects such as sagging are less likely to occur.

In addition, in the manufacturing method of the present invention, from the viewpoint of easy production of an optical laminate having the above characteristics, after peeling the coating film from the support in the step (b), heating the coating film peeled in the step (c) , Manufacturing a film. However, the optical layered product of the present invention may be a film manufactured by any manufacturing method as long as the _{optical film or optical layered product has the characteristics related to the Y mh or the like.} For example, before peeling the coating film from the support body, the coating film may be post-baked, and the film after the post-baking may be peeled from the support body to be produced.

Next, in step (d), a functional layer is laminated on at least one side of the film to obtain the optical laminate of the present invention. As a method of laminating a functional layer on at least one side of the film, a method of coating a composition for forming a functional layer on at least one side of the film, drying and/or curing, etc. as necessary, and laminating it, and a film shape on at least one side of the film The method of bonding and laminating the functional layers of is mentioned. From the viewpoint of easy to increase the optical homogeneity of the optical laminate, it is preferable to coat the functional layer-forming composition to laminate the functional layer.

The manufacturing method of the present invention may further include a step (e) of evaluating a film or an optical laminate to be described later after the step (c) or after the step (d). In step (e), the line profile in the direction h and the direction v perpendicular to each other in the film inverse space obtained by Fourier transforming the projection image obtained by the projection method using the obtained film or optical laminate, respectively, the line profile h And a line profile v, and lines in directions h'and v'perpendicular to each other on a background inverse space obtained by Fourier transform of a background image obtained without using the film or the optical laminate in the projection method. The profiles are called line profile h'and line profile v', respectively, and the maximum intensity of the line profile (h-h') obtained by subtracting the line profile h'from the line profile h is _{called Y mh} , and the frequency representing the maximum intensity Y _mh Is X _mh , and the maximum intensity of the line profile (v-v') obtained by subtracting the line profile v'from the line profile v is _{called Y mv} , and the frequency representing the _{maximum intensity Y mv} is called _{X mv.} Film or optical based on the values of _mh and Y _mv , and the value of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 _{calculated from Y mh} , Y _mv , X _mh and X _mv It is a process of evaluating a laminate.

In step (e), based on _{the values of Y mh} and Y _mv , and the values of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 , the optical homogeneity of the film or optical laminate is to be evaluated. I can. For example, by setting a predetermined value according to the required optical homogeneity, comparing the value with the result obtained for the film or optical laminate, judging the quality of the film, and classifying the film, Y _{The values of mh} and Y _mv , and the values of (Y _mh +Y _mv )/(X _mh +X _mv ) ^1/2 are less than or equal to a predetermined value, and an optical film or optical laminate having excellent optical homogeneity can be prepared. have. Further, while evaluating the above values, drying conditions and the like can be adjusted to produce the optical laminate of the present invention having the above characteristics.

In the process (e) of evaluating the film _{, based on the maximum intensity Y mh} and Y _mv measured by the evaluation method of the present invention, the optical homogeneity is evaluated, and the quality of the optical film or the optical laminate is judged. It is preferable from the viewpoint of being able to efficiently manufacture an optical laminated body excellent in optical homogeneity. The criterion for determining the quality of the optical film or the optical laminate may be appropriately set according to the use of the finally obtained optical laminate or optical homogeneity required for the optical laminate, and is not particularly limited. For the purpose of obtaining an optical laminate having excellent homogeneity that is suitably used as an optical film, etc., in the case of determining the quality of the optical film or the optical laminate, the optical film included in the optical laminate of the present invention On the other hand, it is preferable to judge whether or not the optical laminate of the present invention has the characteristics described above based on whether or not it has the characteristics described above.

According to the said evaluation process, it becomes possible to evaluate optical homogeneity with higher precision compared with the conventional evaluation method. Specifically, according to the evaluation process, it is possible to evaluate non-uniformity in optical properties, which occurs due to non-uniformity in both directions in the TD direction and in the MD direction, which cannot be evaluated with sufficient precision in the conventional evaluation method, or a non-uniformity in which the width is different And it is possible to evaluate the optical homogeneity with high precision regardless of the type of non-uniformity. Moreover, it is also possible to quantify the homogeneity of a film or an optical laminated body by the said evaluation process. In addition, in this specification, the optical film or optical laminated body used as a measurement object in an evaluation process is also called "a measurement film." The evaluation step in step (e) is, specifically, the following steps (1) to (5):

(1) a step of obtaining a projection image by a projection method of irradiating light from a light source to a measurement film and projecting light transmitted through the measurement film onto a projection surface,

(2) The step of obtaining a background image by projecting light from a light source onto a projection surface without using a measurement film in the projection method of step (1),

(3) The projection image obtained in step (1) and the background image obtained in step (2) are digitized by gray scale, respectively, and the digitized image data is Fourier transformed to form an inverse space image (film inverse space image and background inverse space). The process of obtaining a prize),

(4) A step of obtaining a blank-corrected line profile by subtracting each line profile of the two directions orthogonal in the reverse space of the background image from each line profile of two directions orthogonal in the reverse space of the projection image. ,

And,

(5) The process of measuring the _{maximum intensity (Y mh} and Y _mv ) of the blank corrected line profile obtained in step (4)

It includes at least.

In step (1), light from a light source is irradiated onto a measurement film, and light that has passed through the measurement film is projected onto a projection surface to obtain a projection image. In the step (1), for example, as shown in FIG. 1, a measurement film, a projection surface, and the like may be disposed. Specifically, the light source 1, the measurement film 2, and the projection surface 3 are arranged, the projection image 4 projected on the projection surface 3 is photographed with the camera 6, and a projection image is obtained. The light 5 output from the light source 1 passes through the measurement film 2, and the transmitted light is projected onto the projection surface 3 as a projection image 4. When the light 5 passes through the measurement film 2, if the measurement film 2 is homogeneous, the light 5 uniformly passes through the measurement film 2 to reach the projection surface 3, but the measurement film ( 2) In the case of non-uniformity, non-uniform surface shape, non-uniform thickness, non-uniform orientation, etc., reflection and/or refraction are generated when light 5 passes through the measurement film 2, and output from the light source. Compared with the state, the light in a distorted state reaches the projection surface 3. By evaluating the projection image 4 thus obtained by the method described later, the optical homogeneity of the measurement film can be evaluated or quantified with high precision. From the viewpoint of easy obtaining a clear projection image, it is preferable to perform photographing by transmitting only the light from the light source through the measurement film in a dark room. The kind of the light source is not particularly limited, and for example, an LED light source or a halogen lamp may be used. A light source close to the point light source is preferred, and the light emitting portion is preferably 1 cm in diameter or less. Since the projection image tends to become unclear when passing through a filter or a lens, light that does not pass through the filter or lens is preferable. The projection surface is not particularly limited as long as the projection image of the measurement film is visually recognized, but for example, an acrylic plate, a vinyl chloride plate, a polyethylene plate, a screen for a movie, or the like may be used. The photographing method of the image projected on the projection surface is not particularly limited, for example, as shown in FIG. 1, the projection surface 3, the measurement film 2, and the light source 1 are arranged in a straight line, and the projection surface 3 The camera 6 may be fixed and photographed at a position where the projection image 4 projected to is taken at an angle. The photographing mode may be appropriately set, and for example, settings as described in the examples may be used. In this way, a projection image is obtained.

In step (2), in the projection method of step (1), without using a measurement film, light from a light source is projected onto a projection surface to obtain a projection image. Specifically, in Fig. 1, for example, photographing is performed with only the measurement film 2 removed to obtain a background image.

In the step (3), the projection image obtained in the step (1) and the background image obtained in the step (2) are digitized by gray scale, respectively, and the digitized image data is Fourier transformed to obtain an inverse spatial image. Gray scale can be performed by using an image analysis software (for example, "Image-J" manufactured by the US National Institute of Health Research), for example, by making an 8-bit gray scale. By gray-scaling, the projection image and the background image can be converted into numerical values. Subsequently, the digitized image data is Fourier transformed to obtain an inverse space image (a film inverse space image and a background inverse space image). By Fourier transforming the digitized image data, the period and amplitude of the shade of the image can be obtained. As a method of Fourier transform, for example, using the Fourier transform function of image analysis software (Image-J), etc. are mentioned.

In step (4), each line profile in the two directions orthogonal in the reverse space of the background image is subtracted from each line profile in two directions orthogonal in the reverse space of the projected image, and blank-corrected lines Get the profile.

_{In step (5), the maximum intensity Y max} (Y _mh and Y _mv , respectively) of the blank-corrected line profile obtained in step (4) is measured. The measurement methods of Y _mh and Y _mv are as described above for the measurement film, for example, in the horizontal direction (h1 direction) and the vertical direction (v1 direction) passing through the center of the reverse space. In the case of creating a line profile, for example, as shown in Fig. 3, it is shown as a graph showing the frequency on the X-axis and the intensity on the Y-axis. _{And, the maximum intensity Y max} in the line profile in the horizontal direction (h1 direction) is _{called Y mh1} , and X is a value obtained by subtracting _{the median value X cen} of all frequencies in the blank corrected line profile from the frequency representing the maximum intensity Y _{mh1. Let max} be X _mh1 . _{In addition, the maximum intensity Y max} in the line profile in the vertical direction (v1 direction) is referred to as Y _mv1 , and X is a value obtained by subtracting _{the median value X cen} of all frequencies in the blank corrected line profile from the frequency representing the maximum intensity Y _{mv1. Let max} be X _mv1 . Further, the two directions are not particularly limited as long as they are orthogonal to each other, and may be two directions not passing through the center, and may not be horizontal and vertical.

By measuring the said Y _mh and Y _mv , homogeneity can be evaluated in the two-dimensional direction of a measurement film. The surface shape unevenness that causes one cause of lowering the optical homogeneity of the measurement film includes a kind of non-uniformity that cannot be sufficiently detected in one-dimensional evaluation, such as, for example, a stripe shape non-uniformity. According to the evaluation method of the present invention, since optical homogeneity can be evaluated in a two-dimensional direction, evaluation can be performed with high precision regardless of the kind of non-uniformity of the measurement film. Further, it is also possible to quantify the homogeneity of the measurement film by measuring _{the Y mh} and Y _{mv to obtain a value.}

In addition to the maximum intensities Y _mh and Y _mv , evaluation is performed using _{X mh} and X _{mv, which} are values obtained by subtracting _{the median value X cen} of all frequencies in the blank corrected line profile from the frequencies representing these maximum intensities, It is also possible to detect the period in which plane shape non-uniformity occurs, which is one cause that affects the optical homogeneity of the measurement film.

The optical laminated body of the present invention may be a film roll wound around a core. The material constituting the core is not particularly limited, but for example, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyester resin, epoxy resin, phenol resin, melamine resin, silicon resin, polyurethane resin, polycarbonate resin Synthetic resins such as ABS resin; Metals such as aluminum; Fiber-reinforced plastic (FRP: a composite material in which fiber such as glass fiber is contained in plastic to improve strength) may be used. The shape of the core is also not particularly limited, but it is preferably a cylindrical shape or a cylindrical shape. When the core is cylindrical or cylindrical, the outer diameter is preferably 1 to 12 inches, more preferably 3 to 10 inches, and still more preferably 3 to 6 inches from the viewpoint of strength and operability. In addition, the longitudinal length of the winding core is preferably 1.0 to 2.0 times, more preferably 1.0 to 1.8 times, further preferably 1.0 to 1.5 times the length in the width direction of the transparent resin film to be wound from the viewpoint of operability. to be.

When the optical laminate of the present invention is in the form of a film roll, in the manufacturing process of the optical laminate, the optical laminate having an optical film and a functional layer, and optionally a protective film may have a form wound around a core in a roll shape. . The optical film may not be peeled off from the support, and all of the support may be wound. The optical laminate of the present invention may be an optical laminate in the form of a film roll, or a film obtained by cutting the optical laminate in the form of a film roll.

The optical layered product of the present invention has a length in the width direction of preferably 20 cm or more, more preferably 30 cm or more, more preferably 40 cm or more, even more preferably 50 cm or more, especially from the viewpoint of increasing optical homogeneity. It is preferably 60 cm or more. The upper limit of the length in the width direction is not particularly limited, but may be, for example, about 200 cm or less. In addition, the optical laminate of the present invention has a length in the longitudinal direction of preferably 1 m or more, more preferably 10 m or more, still more preferably 100 m or more, even more preferably 200 m or more, from the viewpoint of easy optical homogeneity. , Even more preferably 300m or more, particularly preferably 400m or more. The upper limit of the length in the longitudinal direction is not particularly limited, and may be, for example, about 5000 m or less. By laminating at least one functional layer on the optical film having the above size, an optical laminate having the above size can be manufactured. The optical laminate having the above size is preferably manufactured by a roll-to-roll method, that is, it is preferably in the form of a film roll from the viewpoint of easy optical homogeneity. From the obtained film roll, it can cut out and use an optical laminated body according to the size of a required flexible device.

When the size of the optical laminate or the optical film is large, for example, as described above, a film having a predetermined size (for example, 200 mm×300 mm) is cut out to form a measurement film, and the Y _{mh calculated for the measurement film} You may evaluate values such as. You may measure a plurality of sheets and evaluate using the average value of the obtained values. The preferable range of the average value is the same as the above _{range for Y mh and the like.}

<protective film>

A protective film may be laminated on the optical laminate of the present invention. The protective film may be laminated on one side or both sides of the optical laminate. When the optical laminate has a functional layer on one side and no functional layer on the other side, the protective film may be laminated on the surface of the functional layer side of the optical laminate, or may be laminated on the surface of the optical film side. It may be laminated on both sides. When the optical laminate has a functional layer on both sides, the protective film may be laminated on the surface on the side of the functional layer on one side or may be laminated on the surface on the side of the functional layer on both sides. The protective film is a film for temporarily protecting the surface of the optical film or functional layer, and is not particularly limited as long as it is a peelable film capable of protecting the surface of the optical film or functional layer. Examples of the protective film include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Polyolefin resin films such as polyethylene and polypropylene films, acrylic resin films, and the like, and are preferably selected from the group consisting of polyolefin resin films, polyethylene terephthalate resin films, and acrylic resin films. When two protective films are laminated on the optical laminate of the present invention, each protective film may be the same or different.

The thickness of the protective film is not particularly limited, but is usually 10 to 120 µm, preferably 15 to 110 µm, and more preferably 20 to 100 µm. When two protective films are laminated on the optical laminate of the present invention, the thickness of each protective film may be the same or different.

<Flexible display device>

The present invention also provides a flexible display device including the optical laminate of the present invention. The optical laminate of the present invention is preferably used as a front plate in a flexible display device, and the front plate is sometimes referred to as a window film. The flexible display device includes a laminate for a flexible display device and an organic EL display panel, and a laminate for a flexible display device is disposed on the viewing side of the organic EL display panel to be bent. The laminate for a flexible display device may further contain a polarizing plate (preferably a circular polarizing plate), a touch sensor, and the like, and the order of lamination thereof is arbitrary, but the order of the window film, the polarizing plate, and the touch sensor from the viewing side, or, It is preferable that they are laminated in the order of a window film, a touch sensor, and a polarizing plate. If the polarizing plate is present on the viewing side rather than the touch sensor, the pattern of the touch sensor is difficult to be recognized, and the visibility of the displayed image is improved, which is preferable. Each member may be laminated using an adhesive or an adhesive. In addition, the flexible display device may include a light blocking pattern formed on at least one surface of any layer of the window film, the polarizing plate, and the touch sensor.

<Circular polarizer>

As described above, the flexible display device of the present invention preferably includes a polarizing plate and a circular polarizing plate. The circular polarizing plate is a functional layer having a function of transmitting only a right or left circular polarization component by laminating a λ/4 retardation plate on a linear polarizing plate. For example, it is used to convert the external light into right circular polarized light and block the external light that is reflected by the organic EL panel and become left circular polarized light, and to suppress the influence of the reflected light by transmitting only the light emitting component of the organic EL to make the image easier to see. . In order to achieve the circular polarization function, the absorption axis of the linear polarizing plate and the slow axis of the λ/4 retardation plate need to be 45 degrees in theory, but are practically 45±10 degrees. The linear polarizing plate and the λ/4 retardation plate do not necessarily need to be laminated adjacently, and the relationship between the absorption axis and the slow axis may satisfy the above range. Although it is desirable to achieve complete circular polarization in all wavelengths, in practical use, it is not necessary to do so, so the circular polarizing plate in the present invention also includes an elliptically polarizing plate. It is also preferable to laminate a λ/4 retardation film on the viewing side of the linear polarizing plate to make the outgoing light circularly polarized, thereby improving visibility in a state of wearing polarized sunglasses.

The linear polarizing plate is a functional layer having a function of allowing light vibrating in the direction of a transmission axis to pass, but blocking polarization of a vibration component perpendicular thereto. The linear polarizing plate may be configured with a linear polarizer alone or a linear polarizer and a protective film attached to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, and preferably 0.5 to 100 μm. When the thickness of the linear polarizing plate is within the above range, there is a tendency that the flexibility of the linear polarizing plate is difficult to decrease.

The linear polarizer may be a film-type polarizer manufactured by dyeing and stretching a polyvinyl alcohol (hereinafter, sometimes referred to as PVA)-based film. A dichroic dye such as iodine is adsorbed to the PVA-based film oriented by stretching or stretched in a state adsorbed by PVA, whereby the dichroic dye is oriented to exhibit polarization performance. In the production of the film-type polarizer, other steps such as swelling, crosslinking with boric acid, washing with an aqueous solution, and drying may be provided. The stretching and dyeing process may be performed by the PVA-based film alone, or may be performed in a state of being laminated with another film such as polyethylene terephthalate. The thickness of the PVA-based film to be used is preferably 10 to 100 μm, and the draw ratio is preferably 2 to 10 times.

Moreover, as another example of the said polarizer, a liquid crystal coating type polarizer formed by coating a liquid crystal polarizing composition is mentioned. The said liquid crystal polarizing composition may contain a liquid crystal compound and a dichroic dye compound. The liquid crystal compound should have a property that exhibits a liquid crystal state, and particularly, if it has a high-order alignment state such as a Smectic phase, it is preferable because it can exhibit high polarization performance. In addition, it is preferable that the liquid crystal compound has a polymerizable functional group.

The dichroic dye compound is a dye that is oriented together with the liquid crystal compound to exhibit dichroism, and may have a polymerizable functional group, and the dichroic dye itself may have liquid crystallinity.

Any of the compounds contained in the liquid crystal polarizing composition has a polymerizable functional group. The liquid crystal polarizing composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like.

The liquid crystal polarizing layer is produced by forming a liquid crystal polarizing layer by applying a liquid crystal polarizing composition on an alignment film. The liquid crystal polarizing layer can be formed to have a thinner thickness compared to the film-type polarizer, and the thickness is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.

The alignment layer is manufactured by applying an alignment layer forming composition on a substrate and imparting alignment by rubbing or polarization irradiation. The said alignment film-forming composition contains an alignment agent, and may further contain a solvent, a crosslinking agent, an initiator, a dispersing agent, a leveling agent, a silane coupling agent, etc. Examples of the alignment agent include polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides. When using an aligning agent which imparts orientation by polarization irradiation, it is preferable to use an aligning agent containing a cinnamate group. The weight average molecular weight of the polymer used as the aligning agent is, for example, about 10,000 to 1,000,000. The thickness of the alignment film is preferably 5 to 10,000 nm, and more preferably 10 to 500 nm from the viewpoint of sufficiently expressing the orientation regulating force.

The liquid crystal polarizing layer may be peeled off from the substrate and transferred to be laminated, or the substrate may be laminated as it is. It is also preferable that the said base material plays a role as a transparent base material of a protective film, a retardation plate, and a window film.

As the protective film, a transparent polymer film may be used, and the same materials and additives as those used for the transparent substrate of the window film can be used. Moreover, it may be a coating-type protective film obtained by coating and curing a cation curing composition such as an epoxy resin or a radical curing composition such as an acrylate. The protective film may contain a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or dye, a fluorescent whitening agent, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent, etc., if necessary. . The thickness of the protective film is preferably 200 µm or less, more preferably 1 to 100 µm. When the thickness of the protective film is in the above range, there is a tendency that the flexibility of the film is difficult to decrease.

The λ/4 retardation plate is a film that imparts a phase difference of λ/4 in a direction perpendicular to the advancing direction of incident light (in-plane direction of the film). The λ/4 retardation plate may be a stretched retardation plate manufactured by stretching a polymer film such as a cellulose film, an olefin film, or a polycarbonate film. The λ/4 retardation plate is, if necessary, a retardation adjuster, a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or dye, a fluorescent whitening agent, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent. It may contain, etc.

The thickness of the stretched retardation plate is preferably 200 µm or less, more preferably 1 to 100 µm. When the thickness of the stretched retardation plate is within the above range, there is a tendency that the flexibility of the stretched retardation plate is hardly lowered.

Further, as another example of the λ/4 retardation plate, a liquid crystal coating type retardation plate formed by applying a liquid crystal composition may be mentioned.

The liquid crystal composition contains a liquid crystal compound that exhibits a liquid crystal state such as nematic, cholesteric, and smectic. The liquid crystalline compound has a polymerizable functional group.

The liquid crystal composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like.

The liquid crystal coating type retardation plate can be manufactured by forming a liquid crystal retardation layer by coating and curing a liquid crystal composition on a base, similarly to the liquid crystal polarizing layer. The liquid crystal coating type retardation plate can be formed to be thinner than the stretched retardation plate. The thickness of the liquid crystal polarizing layer is preferably 0.5 to 10 µm, more preferably 1 to 5 µm.

The liquid crystal coating type retardation plate may be peeled from the substrate and transferred to be laminated, or the substrate may be laminated as it is. It is also preferable that the said base material plays a role as a transparent base material of a protective film, a retardation plate, and a window film.

In general, the shorter the wavelength, the greater the birefringence, and the longer the wavelength, the smaller the number of materials. In this case, since a phase difference of λ/4 cannot be achieved in the entire visible light region, the in-plane phase difference is preferably 100 to 180 nm, more preferably 130 so that λ/4 is achieved in the vicinity of 560 nm with high visibility. It is designed to be ~150nm. An inverse dispersion λ/4 retardation plate using a material having a birefringence wavelength dispersion characteristic opposite to that of usual is preferable from the viewpoint of improving visibility. As such a material, for example, those described in Japanese Unexamined Patent Publication No. 2007-232873 and the like for the stretchable retardation plate, and those described in Japanese Unexamined Patent Publication No. 2010-30979 for the liquid crystal coating type retardation plate can be used.

In addition, as another method, a technique of obtaining a broadband λ/4 phase difference plate by combining with a λ/2 phase difference plate is also known (for example, Japanese Unexamined Patent Application Publication No. Hei 10-90521). The λ/2 phase difference plate is also manufactured by the same material method as the λ/4 phase difference plate. The combination of the stretched retardation plate and the liquid crystal coated retardation plate is arbitrary, but any of them can be made thin by using a liquid crystal coated retardation plate.

A method of laminating a positive C plate to the circular polarizing plate in order to increase visibility in an oblique direction is known (for example, Japanese Unexamined Patent Application Publication No. 2014-224837). The positive C plate may be a liquid crystal coating type retardation plate or a stretch type retardation plate. The retardation in the thickness direction of the retardation plate is preferably -200 to -20 nm, more preferably -140 to -40 nm.

<Touch sensor>

As described above, it is preferable that the flexible display device of the present invention includes a touch sensor. The touch sensor is used as an input means. Examples of the touch sensor include various forms such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitive method, and preferably a capacitive method is mentioned.

The capacitive touch sensor is divided into an active area and an inactive area located at an outer portion of the active area. The active area is an area corresponding to an area (display unit) in which the screen is displayed on the display panel, and is an area where a user's touch is sensed, and the inactive area is an area corresponding to an area in which the screen is not displayed (non-display area) on the display device . The touch sensor includes a substrate having a flexible characteristic, a sensing pattern formed in the active region of the substrate, and each sensing line formed in the non-active region of the substrate and connected to an external driving circuit through the sensing pattern and the pad part. It may include. As the substrate having flexible properties, the same material as the transparent substrate of the window film can be used.

The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and each pattern must be electrically connected in order to sense a touched point. In the first pattern, a plurality of unit patterns are connected through a seam, but the second pattern has a structure in which a plurality of unit patterns are separated from each other in the form of an island, so a separate bridge is used to electrically connect the second pattern. You need an electrode. A known transparent electrode can be applied to the electrode for connection of the second pattern. Examples of the material for the transparent electrode include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), and cadmium tin oxide. (CTO), PEDOT (poly(3,4-ethylenedioxythiophene)), carbon nanotubes (CNT), graphene, metal wire, and the like, and preferably ITO is used. These can be used alone or in combination of two or more. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium, and these may be used alone or in combination of two or more. .

The bridge electrode may be formed on the insulating layer by interposing an insulating layer on the sensing pattern, a bridge electrode may be formed on a substrate, and an insulating layer and a sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, or may be formed of molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of them.

Since the first pattern and the second pattern must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint of the first pattern and the bridge electrode, or may be formed as a layer covering the entire sensing pattern. In the case of a layer covering the entire sensing pattern, the bridge electrode may connect the second pattern through a contact hole formed in the insulating layer.

The touch sensor includes a difference in transmittance between a pattern region in which a sensing pattern is formed and a non-pattern region in which a sensing pattern is not formed, specifically, a light transmittance caused by a difference in refractive indices in these regions. As a means for appropriately compensating for the difference, an optical control layer may be further included between the substrate and the electrode. The optical control layer may include an inorganic insulating material or an organic insulating material. The optical control layer may be formed by coating a photocurable composition including a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The refractive index of the optical control layer can be increased by the inorganic particles.

The photocurable organic binder may include a copolymer of each monomer such as, for example, an acrylate-based monomer, a styrene-based monomer, and a carboxylic acid-based monomer within a range that does not impair the effects of the present invention. The photocurable organic binder may be, for example, a copolymer containing different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit.

Examples of the inorganic particles include zirconia particles, titania particles, and alumina particles.

The photocurable composition may further contain additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

<Adhesive layer>

Each layer (window film, circular polarizing plate, touch sensor) forming the laminate for the flexible image display device and the film member (straight polarizing plate, λ/4 retardation plate, etc.) forming each layer can be bonded with an adhesive. . Examples of the adhesive include water-based adhesives, organic solvents, solvent-free adhesives, solid adhesives, water-based solvent vaporization adhesives, moisture curing adhesives, heat curing adhesives, anaerobic curing, active energy ray curing adhesives, curing agent mixture adhesives, heat melting adhesives, Pressure-sensitive adhesives (adhesives), rewet-type adhesives, and the like, commonly used adhesives, etc. can be used, and water-based solvent volatilization-type adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives can be used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force, etc., preferably 0.01 to 500 µm, more preferably 0.1 to 300 µm. Although a plurality of adhesive layers are present in the laminate for a flexible image display device, each thickness and type may be the same or different.

As the aqueous solvent volatilization adhesive, a water-dispersed polymer such as polyvinyl alcohol-based polymer, water-soluble polymer such as starch, ethylene-vinyl acetate-based emulsion, and styrene-butadiene-based emulsion can be used as the main polymer. I can. In addition to the main polymer and water, a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, and the like may be blended. In the case of bonding with the water-based solvent vaporizing adhesive, the water-based solvent vaporizing adhesive is injected between the adhered layers to bond the adhered layers and then dried to impart adhesiveness. In the case of using the aqueous solvent volatilization type adhesive, the thickness of the adhesive layer is preferably 0.01 to 10 µm, more preferably 0.1 to 1 µm. When using the above water-based solvent volatilization adhesive for a plurality of layers, the thickness and type of each layer may be the same or different.

The active energy ray-curable adhesive may be formed by curing an active energy ray-curable composition containing a reactive material that forms an adhesive layer by irradiating with an active energy ray. The active energy ray-curable composition may contain at least one polymer of a radical polymerizable compound and a cation polymerizable compound similar to those contained in the hard coating composition. As the radical polymerizable compound, the same compound as the radical polymerizable compound in the hard coating composition can be used.

As the cation polymerizable compound, the same compound as the cation polymerizable compound in the hard coating composition can be used.

As the cationic polymerizable compound used in the active energy ray curing composition, an epoxy compound is particularly preferable. It is also preferable to include a monofunctional compound as a reactive diluent in order to lower the viscosity as an adhesive composition.

The active energy ray composition may contain a monofunctional compound in order to lower the viscosity. As the monofunctional compound, an acrylate monomer having one (meth)acryloyl group per molecule, or a compound having one epoxy group or oxetanyl group per molecule, such as glycidyl (meth) Acrylate, etc. are mentioned.

The active energy ray composition may further contain a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cation polymerization initiator, a radical and a cation polymerization initiator, and the like, and these are appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cation to advance radical polymerization and cation polymerization. Among the substrates of the hard coating composition, an initiator capable of initiating at least either radical polymerization or cationic polymerization by irradiation with active energy rays can be used.

The active energy ray curing composition may further contain an ion scavenger, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, a defoaming agent, an additive, and a solvent. In the case of bonding two layers to be bonded by the active energy ray-curable adhesive, the active energy ray-curable composition is applied to one or both of the bonded layers, and then bonded together, and active energy rays are applied to either or both of the bonded layers. It can be bonded by irradiating and curing. In the case of using the active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.01 to 20 µm, more preferably 0.1 to 10 µm. When the active energy ray-curable adhesive is used for forming a plurality of adhesive layers, the thickness and type of each layer may be the same or different.

As the pressure-sensitive adhesive, depending on the main polymer, any classified into acrylic pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives may be used. In addition to the main polymer, the pressure-sensitive adhesive may contain a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, an inorganic filler, and the like. Each component constituting the pressure-sensitive adhesive is dissolved and dispersed in a solvent to obtain a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer is formed by drying after coating the pressure-sensitive adhesive composition on a substrate. The adhesive layer may be formed directly or may be transferred to a separate substrate. It is also preferable to use a release film in order to cover the adhesive surface before adhesion. When using the active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.1 to 500 µm, more preferably 1 to 300 µm. In the case of using a plurality of layers of the pressure-sensitive adhesive, the thickness and type of each layer may be the same or different.

<Light-shielding pattern>

The light blocking pattern may be applied as at least a part of a bezel or a housing of the flexible image display device. Since the wiring arranged at the periphery of the flexible image display device is concealed by the light shielding pattern, the visibility of the image is improved. The shading pattern may be in the form of a single layer or a multilayer. The color of the shading pattern is not particularly limited, and various colors such as black, white, and metallic colors may be used. The shading pattern may be formed of a pigment for implementing color and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or silicone. These may be used alone or as a mixture of two or more. The shading pattern may be formed by various methods such as printing, lithography, and inkjet. The thickness of the shading pattern is preferably 1 to 100 µm, more preferably 2 to 50 µm. In addition, it is also preferable to give a shape such as an inclination in the thickness direction of the light shielding pattern.

[Example]

Hereinafter, the present invention will be described in more detail by examples, but the present invention is not limited to the following examples. "%" and "part" in the examples mean mass% and mass parts unless otherwise specified. First, a method of measuring the property value will be described.

<weight average molecular weight>

Gel permeation chromatography (GPC) measurement

(1) Pre-treatment method

A sample was dissolved in γ-butyrolactone (GBL) to obtain a 20% by mass solution, diluted 100 times with a DMF eluent, and filtered through a 0.45 µm membrane filter to obtain a measurement solution.

(2) Measurement conditions

Column: TSKgel SuperAWM-H x 2 + SuperAW 2500 x 1 (6.0 mm I.D. x 150 mm x 3)

Eluent: DMF (10 mmol of lithium bromide added)

Flow: 0.6 mL/min

Detector: RI detector

Column temperature: 40°C

Injection volume: 20 μL

Molecular weight standard: standard polystyrene

<Imidation rate>

The imidation ratio was calculated|required as follows by ^{1 H-NMR measurement.}

(1) Pre-treatment method

The sample was dissolved in deuterated dimethyl sulfoxide (DMSO-d ₆ ) to obtain a 2% by mass solution as a measurement solution.

(2) Measurement conditions

Measurement device: JEOL 400MHz NMR device JNM-ECZ400S/L1

Standard: DMSO-d ₆ (2.5ppm)

Sample temperature: room temperature

Integration count: 256 times

Relaxation time: 5 seconds

(3) Imidation ratio analysis method

(3-1) Imidation rate of polyimide resin A

^{Among the benzene protons observed in the 1} H-NMR spectrum obtained with respect to the measurement solution containing the polyimide resin A, the integral value of the benzene protone A derived from the structure that does not change before and after imidation was referred to _{as Int A.}

In addition, the integral value of the amide proton derived from the amic acid structure remaining in the polyimide resin was referred to _{as Int B.} From these integral values, the imidation ratio of the polyimide resin A was determined based on the following formula. In the following formula, α is the ratio of the number of benzene protons A to one amide proton in the case of a polyamic acid (imidation ratio of 0%).

Imidation rate (%) = 100 × (1-α × Int _B /Int _A )

(3-2) Imidation ratio of polyamideimide resin A

Polyamide-imide resin A of the observed benzene according to ¹ H-NMR spectrum obtained with respect to the measurement solution, proton containing and derived from a structure that does not already have changed in the encoding after, derived from the amic acid structure remaining in the polyamide-imide resin The integral value of benzene proton C, which is not affected by the structure, was called _{Int C.}

In addition, the integral value of benzene proton D, which is influenced by the structure derived from the structure derived from the amic acid structure remaining in the polyamideimide resin A and derived from the structure that does not change before and after imidation among the observed benzene protons, was referred to _{as Int D.} From these integral values, the β value was calculated based on the following equation.

β=Int _D /Int _C

Next, in order to obtain a correlation equation for converting β into an imidation rate, for a plurality of polyamide-imide resins having different imidation rates, the β value was calculated in the same manner as above, and the imidation rate was calculated using the HSQC spectrum. It calculated|required and obtained the following correlation formula from these results.

Imidation rate (%)=k×β+100

In the above correlation equation, k is a constant.

Next, β obtained for the polyamideimide resin A was substituted into the above correlation to obtain an imidation ratio (%) of the polyamideimide resin A.

<Average primary particle diameter>

The specific surface area of the powder obtained by drying the silica sol at 300°C was measured using Yuasa Ionics Co., Ltd., a specific surface area measuring device Monosorb MS-16, and the measured specific surface area S (m ² /g) was used. , D (nm) = 2720/S to calculate the average primary particle diameter.

<Viscosity of varnish>

In conformity with JIS K 8803:2011, it measured using the Brookfield E-type viscometer DV-II+Pro. The measurement temperature was 25°C.

<film thickness>

Using Mitsutoyo Co., Ltd. ID-C112XBS, the thickness of the film of 10 points or more was measured, and the average value was calculated.

<Thickness of functional layer>

The thickness of the functional layer was measured using an F20 tabletop film thickness system manufactured by Filmetrics.

<Total light transmittance of film, Haze>

The optical characteristic values were measured using a spectrophotometer CM-3700A manufactured by Konica Minolta.

<Film yellowness>

The yellowness (Yellow Index: YI value) of the optical film was measured using the Konica Minolta Co., Ltd. spectrophotometer CM-3700A. Specifically, after performing background measurement without a sample, the optical film is set in a sample holder, transmittance to light of 300 to 800 nm is measured, and tristimulus values (X, Y, Z) are obtained, YI value was calculated based on the following formula.

YI=100×(1.2769X-1.0592Z)/Y

In accordance with JIS K 5600-5-4:1999, the pencil hardness of the surface of the functional layer of the optical laminate was measured. The load at the time of measurement was 750 g, and the measurement speed was 4.5 mm/sec.

<Measurement of surface resistivity>

The surface resistivity (Ω/sq) of the optical laminate was measured in accordance with JIS K 6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Hirester UP MCP-HT450 type). The sample was cut into a size of 50 mm x 50 mm, and the obtained sample was allowed to stand at 23° C. and 50% RH for 24 hours. Then, the surface resistivity of the functional layer side of the optical laminate was measured. In addition, the upper limit of the measurement of the device is 1.0E+14?/sq, and when it has a surface resistivity of more than that, it is expressed as OVER on the device.

<Method of evaluating optical homogeneity of optical film or optical laminate>

1. Shooting of projected and background images

In a dark room, as shown in FIG. 2, the light source 1, the measurement film 2, the projection surface 3, and the camera 6 were arrange|positioned, and the projection image 4 was photographed. The distance between the light source 1 and the measurement film 2 is 250 cm, the distance between the measurement film 2 and the projection surface 3 is 30 cm, the measurement film 2 and the projection surface 3 are arranged in parallel, and the camera ( 6) is installed just below the normal to the screen from the light source (1), the distance between the camera 6 and the projection surface (3) (screen) is 30 cm, and the camera angle (7) (the camera is perpendicular to the screen) The angle to be inclined upward from the state facing so that it might be) was 25 degrees. In addition, shooting of the background image was performed similarly to the shooting of the projection image except having removed the measurement film 2 in FIG. The details of the measurement conditions and photography conditions are shown below.

Light source: LED light source (Hayashi Watch Industry Co., Ltd. ``LA-HDF15T'')

Measurement film: The optical film or optical layered product produced in the following Examples and Comparative Examples was cut out into 200 mm x 300 mm to obtain a measurement sample.

Projection surface: White commercially available screen for viewing movies (manufactured by Theater House Co., Ltd., 「BTP600FHD-SH1000」)

Camera: Nikon Co., Ltd. ``COOLPIX (registered trademark) P600''

Camera detailed settings: Manual shooting for shooting mode

Image size 2M

Focus Manual focus (distance 0.3m)

1/2 second shutter speed

Aperture value (F value) 4.2

Flash OFF

2. Fourier Transform

In this embodiment, since the camera is installed at the position of the camera angle, an inclination occurs in the projected image. For this reason, in order to correct the inclination of the projected image first, the inclination correction condition was determined. Further, when there is no distortion of the projection image, correction is unnecessary.

(Decision of slope correction conditions)

A 10 cm x 10 cm square was drawn on a transparent film, and a reference projection image was taken under the conditions of 1 above. The obtained reference projection image was read by Photoshop (registered trademark) CS4 manufactured by Adobe Systems, and corrected so that the camera and the screen corresponded to 90 degrees using the distortion correction function of lens correction, and saved in TIFF format. The condition at this time was made into the inclination correction condition. From the reference projection image after tilt correction, the length per pixel for each vertical and horizontal was calculated (length: 816 pixels = 10 cm, width: 906 pixels = 10 cm).

(Fourier Transform)

With respect to the measurement film, the projection image obtained as described above was corrected under the tilt correction conditions determined as described above, and the corrected image was saved in a TIFF format. The obtained projected image after tilt correction is converted into image analysis software "Image-J, ver. 1.48" was used to convert it into an 8-bit gray scale to convert it into a numerical value. In addition, the length per pixel of each vertical and horizontal, obtained from the reference projection image after tilt correction, was used as the Set Scale. Among the gray scale images, a rectangular range having a size of 10.2 cm x 11.2 cm (vertical x horizontal) was selected, and the image of the selected range was Fourier transformed using Imag stirring eJ to obtain an inverse spatial image. For the inverse space image after Fourier transform, the correct value (horizontal direction: 1pixel=11.3cm ^-1 , vertical direction: 1pixel=12.55cm ^-1 ) was entered in Set Scale.

3. Measurement of the maximum intensity (Y _mh1 and Y _mv1 ) of the blank corrected line profile

In the reverse space image obtained as described above, a line profile was created for each direction in the horizontal direction (h1 direction) and the vertical direction (v1 direction) passing through the center of the reverse space image. The line width was 10 pixels. The obtained line profile was saved in text format. Next, the data in the text format is read in Microsoft Excel (ver.14.0), and the line profile is normalized as follows, for each direction in the horizontal direction (h1 direction) and the vertical direction (v1 direction), A line profile of Y" is obtained, and the maximum intensity Y _max in each line profile is referred to as Y _mh1 and Y _mv1 , and the median value of the total frequency in the blank corrected line profile X from the frequency representing the maximum intensity Y _mh1 and Y _{mv1 X max} , which is a value obtained by subtracting _{cen , is respectively referred to as X mh1} and X _mv 1. The normalization method will be described using a line profile in the horizontal direction (h1 direction) obtained in Example 1 as an example.

(Standardization method)

The frequency at which the value of Y is maximum is the center of X (X _cen ), and the value of Y at that time is set to Y _cen . Next, _{with respect to X cen} as the center, the average value of Y is calculated for a total area of 100 pixels each for 50 pixels at both ends, and the average value is referred to _{as a base line (Y base ).} Then, _Y'is obtained by correcting the data Y according to the following equation so that Y cen =100 and Y _{base =0.}

By performing the correction on the line profile (data Y) obtained in Example 1 shown in Fig. 4, a line profile A (data Y') as shown in Fig. 5 is obtained.

Subsequently, the same operation was performed for the background image obtained in 1 to obtain a line profile of the background image. Specifically, a line profile B as shown in Fig. 6 was obtained.

Subsequently, from the above profile A, the background profile B was subtracted by Excel to perform blank correction. In Example 1, the data of the line profile B as shown in FIG. 6 was subtracted from the data Y'of the line profile A shown in FIG. 5, and blank-corrected line profiles A-B as shown in FIG. 7 were obtained.

The line profile thus obtained was smoothed to obtain a profile of Y", and this _{was used to measure the maximum intensity (Y mh1} and Y _mv1 ) of the line profile. Smoothing of the graph was performed on 21 data according to the following equation. It performed by calculating _{y i} which is the average value of.

(Sensory evaluation of visibility)

In an indoor environment dimmed to 50 to 100 lux, the produced film was visually inspected at an angle of 80 degrees of elevation, and visibility was evaluated by distortion of the reflected background. The results are shown in Table 2. In addition, the evaluation criteria of visibility are as follows.

◎: No distortion is observed in the background.

(Circle): The distortion is not approximately confirmed in the background.

△: A very close distortion is confirmed in the background, but there is no problem.

×: Clear distortion is confirmed in the background.

<Amount of residual solvent>

Using TG-DTA (EXSTAR6000 TG/DTA6300 manufactured by SII Corporation), the transparent resin films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were heated from 30°C to 120°C, and held at 120°C for 5 minutes Then, the temperature was raised to 400°C at a temperature increase rate of 5°C/min. The ratio of the reduction in the mass of the film at 120°C to 250°C with respect to the mass of the film at 120°C was calculated as the content of the solvent (referred to as the amount of residual solvent).

The abbreviations used in the following Production Examples and Examples are as follows.

TFMB: 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl

6FDA: 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride

TPC: terephthaloyl chloride

OBBC: 4,4'-oxybis (benzoyl chloride)

DMAc: N,N-dimethylacetamide

GBL: γ-butyrolactone

PET: polyethylene terephthalate

<Production Example>

Preparation Example 1: Preparation of polyamideimide resin 1

In a nitrogen gas atmosphere, a reaction vessel equipped with a stirring blade and an oil bath were prepared in a separable flask. 45 parts of TFMB and 768.55 parts of DMAc were put into the reaction vessel installed in the oil bath. The contents in the reaction vessel were stirred at room temperature while TFMB was dissolved in DMAc. Next, 19.01 parts of 6FDA was further put into the reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 3 hours. Thereafter, 4.21 parts of OBBC and then 17.30 parts of TPC were put into a reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 1 hour. Subsequently, 4.63 parts of 4-methylpyridine and 13.04 parts of acetic anhydride were further added into the reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 30 minutes. After stirring, the temperature inside the container was raised to 70°C using an oil bath, maintained at 70°C, and stirred for an additional 3 hours to obtain a reaction solution.

The obtained reaction solution was cooled to room temperature, and put into a large amount of methanol in a yarn shape to precipitate a precipitate. The precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 100°C to obtain a polyamideimide resin 1. The weight average molecular weight of the obtained polyamide-imide resin 1 was 400,000, and the imidation ratio was 99.0%.

Preparation Example 2: Preparation of polyimide resin 1

A reactor equipped with a silica gel tube, a stirring device and a thermometer, and an oil bath were prepared in a separable flask. Into this flask, 75.52 parts of 6FDA and 54.44 parts of TFMB were put. While stirring this at 400 rpm, 519.84 parts of DMAc was added, and stirring was continued until the contents of the flask became a homogeneous solution. Subsequently, stirring was continued for an additional 20 hours while adjusting so that the temperature inside the container was in the range of 20 to 30°C using an oil bath, followed by reaction to produce polyamic acid. After 30 minutes, the stirring speed was changed to 100 rpm. After stirring for 20 hours, the reaction system temperature was returned to room temperature, and 649.8 parts of DMAc was added to adjust the polymer concentration to 10% by mass. Further, 32.27 parts of pyridine and 41.65 parts of acetic anhydride were added, followed by stirring at room temperature for 10 hours to perform imidization. The polyimide varnish was taken out from the reaction vessel. The obtained polyimide varnish was dripped in methanol to perform reprecipitation, the obtained powder was heated and dried to remove the solvent, and a polyimide resin 1 was obtained as a solid content. About the obtained polyimide resin 1, when GPC measurement was performed, the weight average molecular weight was 320,000. In addition, the imidation ratio of the polyimide was 98.6%.

Preparation Example 3: Preparation of silica sol 1

Amorphous silica sol having an average primary particle diameter (average primary particle diameter measured by the BET method) of 12 nm produced by the sol-gel method was used as a raw material, and a GBL-substituted silica sol was prepared by solvent substitution. The obtained sol was filtered through a 10 µm membrane filter to obtain GBL-substituted silica sol 1. In the obtained GBL-substituted silica sol 1, the content of the silica particles was 30 to 32% by mass.

Production Example 4: Preparation of varnish (1)

The polyamideimide resin 1 obtained in Production Example 1 and the silica sol 1 obtained in Production Example 3 were mixed so that the composition ratio of the polyamideimide resin:silica particles in a GBL solvent was 70:30. To the obtained mixture, 2.0 phr of UV-A ultraviolet absorber "Sumisorb (registered trademark) 250" (molecular weight 389, manufactured by Sumika Chemtex Co., Ltd.) and polyamideimide resin with respect to the total mass of the polyamideimide resin and silica particles A bluing agent "Sumiplast (registered trademark) Violet B" (manufactured by Sumika Chemtex Co., Ltd.) of 35 ppm relative to the total mass of the silica particles was added, followed by stirring until uniform, to obtain a varnish (1). The solid content of the varnish (1) was 9.7%, and the viscosity at 25°C was 39,600 cps.

Production Example 5: Preparation of varnish (2)

Polyimide resin 1 obtained in Production Example 2, and a 2.0 phr ultraviolet absorber "Sumisorb 250" (molecular weight 389, manufactured by Sumika Chemtex Co., Ltd.) with respect to the polyimide resin were mixed with GBL:DMAc=1:9 It was dissolved in a solvent at a concentration of 16.5% by mass to obtain a varnish (2). The solid content of the varnish (2) was 16.5%, and the viscosity at 25°C was 36,800 cps.

Preparation Example 6: Photocurable Resin Composition 1

Trimethylolpropane triacrylate (Shin-Nakamura Chemical Co., Ltd. product, A-TMPT) 28.4 parts by mass, pentaerythritol tetraacrylate (Shin-Nakamura Chemical Co., Ltd. product, A-TMMT) 28.4 parts by mass, as a photopolymerization initiator, 1 -Hydroxycyclohexylphenyl ketone (BASF Co., Ltd., Irgacure (registered trademark) 184) 1.8 parts by mass, lithium bis (fluorosulfonyl) imide (Tokyo Chemical Industry Co., Ltd. product, LiFSI) 2.4 parts by mass, 0.1 parts by mass of a leveling agent (manufactured by BIC Chemie Japan Co., Ltd., BYK (registered trademark)-307), and 39 parts by mass of propylene glycol 1-monomethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) are stirred and mixed, and a photocurable resin Composition 1 was obtained.

Preparation Example 7: Photocurable Resin Composition 2

Except for not mixing lithium bis(fluorosulfonyl)imide, the same compound as in Production Example 6 was stirred and mixed to obtain a photocurable resin composition 2.

Example 1

The varnish (1) was applied onto a PET film (Toyobo Co., Ltd. "Cosmoshine (registered trademark) A4100", thickness 188 µm, thickness distribution ±2 µm), cast-molded, and a coating film of the varnish was formed. At this time, the ship speed was 0.8 m/min. The coating film of the varnish was heated at 80°C for 10 minutes, then heated at 100°C for 10 minutes, then heated at 90°C for 10 minutes, and finally dried under the drying conditions of heating at 80°C for 10 minutes, and the dried coating film was Formed. Thereafter, the coating film was peeled from the PET film to obtain a raw material film 1 in the form of a film roll having a thickness of 58 µm, a width of 700 mm, and a length of 500 m. The amount of residual solvent in the raw material film 1 was 9.7% by mass. Subsequently, the raw material film 1 was heated at 200° C. for 25 minutes with a film transverse stretching device (tenter) under the conditions of a draw ratio of 0.98 times to obtain a polyamideimide film 1 having a thickness of 50 μm. The amount of residual solvent in the polyamideimide film 1 was 0.7% by mass.

The photocurable resin composition 1 was coated on one side of the obtained polyamideimide film 1 by a roll-to-roll system with a bar coater so that the thickness after drying became 10 µm. Thereafter, drying was performed in an oven at 80° C. for 3 minutes, and ^{irradiated with ultraviolet rays with an energy of 500 mJ/cm 2} of a high-pressure mercury lamp and cured to obtain an optical laminate 1 in the form of a film roll having a length of 400 m. The thickness of the functional layer in the optical laminate 1 was 10 µm.

Example 2

In place of the photocurable resin composition 1, except for using the photocurable resin composition 2, in the same manner as in Example 1, an optical laminate 2 in the form of a film roll having a length of 400 m was obtained. The thickness of the functional layer in the optical laminate 2 was 11 µm.

Example 3

Using varnish (2) instead of varnish (1), drying conditions were heated at 75°C for 7.5 minutes, then heated at 120°C for 7.5 minutes, followed by heating at 70°C for 7.5 minutes, and finally at 80°C for 7.5 minutes. Except having changed to heating conditions, it carried out similarly to Example 1, and obtained the raw material film 2 in the form of a film roll of 89 micrometers in thickness, 700 mm in width, and 600 m in length. The amount of residual solvent in the raw material film 2 was 9.6% by mass. Next, it carried out similarly to Example 1 except having used the raw material film 2 instead of the raw material film 1, and obtained the polyimide film 1 of 77 micrometers in thickness. The amount of residual solvent in the polyimide film 1 was 1.1% by mass.

In the same manner as in Example 2 except that the polyimide film 1 was used instead of the polyamideimide film 1, an optical laminate 3 in the form of a film roll having a length of 500 m was obtained. The thickness of the functional layer in the optical laminate 3 was 9 µm.

Comparative Example 1

Using varnish (1), the drying conditions were changed to heating at 70°C for 10 minutes, then heating at 80°C for 10 minutes, then heating at 100°C for 10 minutes, and finally heating at 100°C for 10 minutes. Other than that, in the same manner as in Example 1, a raw material film 3 in the form of a film roll having a thickness of 58 µm, a width of 700 mm and a length of 400 m was obtained. The amount of residual solvent in the raw material film 3 was 10.1% by mass. Next, it carried out similarly to Example 1 except having used the raw material film 3 instead of the raw material film 1, and obtained the polyamide-imide film 2 of 50 micrometers in thickness. The amount of residual solvent in the polyamideimide film 2 was 0.8% by mass.

In the same manner as in Example 2, except that the polyamideimide film 2 was used instead of the polyamideimide film 1, an optical laminate 4 in the form of a film roll having a length of 290 m was obtained. The thickness of the functional layer in the optical laminate 4 was 10 µm.

Comparative Example 2

Using varnish (2), the drying conditions were changed to heating at 100°C for 7.5 minutes, heating at 120°C for 7.5 minutes, followed by heating at 60°C for 7.5 minutes, and finally heating at 60°C for 7.5 minutes. Except that, in the same manner as in Example 1, a raw material film 4 in the form of a film roll having a thickness of 89 µm, a width of 700 mm and a length of 300 m was obtained. The amount of residual solvent in the raw material film 4 was 9.9% by mass. Next, it carried out similarly to Example 1 except having used the raw material film 4 instead of the raw material film 1, and obtained the polyimide film 2 of 77 micrometers in thickness. The amount of residual solvent in the polyimide film 2 was 1.0% by mass.

In the same manner as in Example 2 except that the polyimide film 2 was used instead of the polyamideimide film 1, an optical laminate 5 in the form of a film roll having a length of 190 m was obtained. The thickness of the functional layer in the optical laminate 5 was 11 µm.

For the optical laminates obtained in Examples and Comparative Examples, the results of measuring various physical property values according to the above measurement method are shown in Tables 1 and 2. In addition, the Haze of the films of Examples and Comparative Examples were all 0.2. In addition, for each value for evaluating optical homogeneity in Table 2, the value in which the measurement sample is described as a film is a value measured for the polyamideimide film or polyimide film before laminating the functional layer, and the measurement sample The value described as a temporary laminate is a value measured with respect to the optical laminate after lamination of the functional layer. The evaluation of visibility is a result of evaluating the optical laminate.

The optical laminates of Examples 1 to 3 or the optical films contained in the optical laminates have Y _mh and Y _mv of 40 or less, A/B of less than 30, and all evaluation of visibility is good as ◎ or ○ did. In contrast, in the optical films included in the optical laminates of Comparative Examples 1 and 2, Y _mh exceeded 40, A/B was 30 or higher, and the evaluation results of visibility were Δ and ×, respectively. In addition, with respect to the optical laminates of Comparative Examples 1 and 2, _{results such as Y mh} when using the optical laminate as a measurement film are not described, but in the same manner as the results obtained using the optical film as a measurement film, Y _mh and the like, and It is thought that A/B does not fall within the range specified for the optical laminate of the present invention. In addition, it was possible to impart an antistatic function in addition to the hard coating function to the functional layer in the optical laminate of Example 1. Similarly, the functional layers of Examples 1 to 3 were layers that may impart new functions such as an antistatic function, an antiglare function, a low reflection function, an antireflection function and an antifouling function in addition to the hard coating function.

1 light source
2 measuring film
3 projection plane
4 Projection image
5 light
6 camera
7 camera angle

Claims (12)

An optical laminate comprising an optical film containing a polyimide resin containing a fluorine atom, and a functional layer having a hard coating function laminated on at least one side of the optical film,
The line profiles in directions h and v perpendicular to each other in the film inverse space obtained by Fourier transform of the projection image obtained by the projection method using the optical film are referred to as line profile h and line profile v, respectively, and the projection method In the background inverse space obtained by Fourier transform of a background image obtained without using the optical laminate, the line profiles in directions h'and v'that are orthogonal to each other are defined as a line profile h'and a line profile v', respectively. The maximum strength of the line profile (h-h') obtained by subtracting the line profile h'from the line profile h is _{called Y mh} , and the frequency representing the _{maximum strength Y mh is called X mh} , and the line profile from line profile v Assuming that the maximum intensity of the line profile (v-v') obtained by subtracting _{v'is called Y mv} and the frequency representing the maximum intensity Y mv is called _{X mv , both Y mh} and Y _mv are 40 or less, and Y _mh , Y _mv , X _mh and X _mv are related to:

To meet,
The functional layer is a layer containing a cured product of a polyfunctional (meth)acrylate-based compound, and the pencil hardness of the surface having the functional layer of the optical laminate is 2H or more,
The polyimide resin is a polyimide resin having a structural unit represented by the following formula (1), or a polyamideimide resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) Phosphorus, optical laminate.

[In formula (1), Y represents a tetravalent organic group, in formula (2), Z is a divalent organic group, and in formulas (1) and (2), X is independently of each other, Represents a divalent organic group] The method of claim 1,
The optical laminated body, wherein the thickness of the functional layer is 20 µm or less. The method according to claim 1 or 2,
The optical laminate having a yellowness of 3.0 or less. The method according to claim 1 or 2,
An optical laminate having a length of 20 cm or more in the width direction of the optical laminate and 1 m or more of a length in the length direction of the optical laminate. The method according to claim 1 or 2,
The optical laminated body is an optical laminated body which is a film for a front plate of a flexible display device. A flexible display device comprising the optical laminate according to claim 1 or 2. The method of claim 6,
A flexible display device further comprising a touch sensor. The method of claim 6,
A flexible display device further comprising a polarizing plate. As the manufacturing method of the optical laminated body according to claim 1 or 2,
(a) a process of applying a varnish containing at least a polyimide resin containing a fluorine atom and a solvent on a support and drying to form a coating film,
(b) the step of peeling the coating film from the support,
(c) heating the peeled coating film to obtain a film, and
(d) a step of laminating a functional layer on at least one side of the film to obtain an optical laminate
The manufacturing method of an optical laminated body containing at least. delete delete delete

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