JP6626950B2 - Optical laminate - Google Patents

Description

  The present invention relates to an optical laminate used as a front plate or the like of an image display device.

  2. Description of the Related Art Image display devices such as liquid crystal display devices and organic EL display devices are widely used for various uses such as mobile phones and smart watches, and in recent years, flexible displays have been developed. As a front plate of such an image display device, an optical laminate having a resin film and a hard coat layer laminated on at least one surface of the resin film has been studied (for example, WO2017 / 014287). issue). Such an optical laminate is disposed on a polarizing plate or the like included in an image display device via an adhesive or the like.

WO 2017/014287

  However, according to the study of the present inventor, the optical laminate may not have sufficient wiping properties such as fingerprints on the surface on the viewing side, or if the optical laminate is repeatedly bent, a resin film and a hard coat may be formed. It has been found that the visibility of the display portion may be reduced because the interface between the layers or the interface between the hard coat layer and the adhesive or the like is separated or deteriorated.

  Therefore, an object of the present invention is to provide an optical laminate that is excellent in wiping properties of fingerprints and the like and bending resistance, and can exhibit excellent visibility.

As a result of intensive studies, the present inventors have found that an optical laminate having a resin film, a first hard coat layer laminated on one surface of the resin film, and a second hard coat layer laminated on the other surface. In the body, the oleic acid contact angle of the first hard coat layer is 65 ° or more and the oleic acid contact angle of the second hard coat layer is 1 ° or more and less than 65 °, and the number of bending of the resin film is more than 100,000 times. If the indentation hardness of the resin film is set to 350 N / mm ² or more, or the value of the impact absorption energy of the optical laminate is set to 100 kJ / m ² , it is found that the above problem can be solved, and the present invention is completed. Reached.

[1] An optical laminate having a resin film containing a polyimide resin, a first hard coat layer laminated on one surface of the resin film, and a second hard coat layer laminated on the other surface In a MIT bending fatigue test with a bending radius of 3 mm in accordance with ASTM standard D2176-16, the resin film has a number of bending exceeding 100,000 times, and the first hard coat layer has an oleic acid contact angle of 65. ° or more, and the second hard coat layer has an oleic acid contact angle of 1 ° or more and less than 65 °.
[2] An optical laminate having a resin film containing a polyimide resin, a first hard coat layer laminated on one surface of the resin film, and a second hard coat layer laminated on the other surface The resin film has an indentation hardness of 350 N / mm ² or more measured using a nano indenter in a cross section in the thickness direction, and the first hard coat layer has an oleic acid contact angle of 65 ° or more. The optical laminate, wherein the second hard coat layer has an oleic acid contact angle of 1 ° or more and less than 65 °.
[3] An optical laminate having a resin film containing a polyimide resin, a first hard coat layer laminated on one surface of the resin film, and a second hard coat layer laminated on the other surface Wherein the first hard coat layer has an oleic acid contact angle of 65 ° or more, the second hard coat layer has an oleic acid contact angle of 1 ° or more and less than 65 °, and has a shock absorption energy by a Charpy impact test Is 100 kJ / m ² or more.
[4] The optical laminate according to any one of [1] to [3], wherein the polyimide-based resin has a weight average molecular weight in terms of polystyrene of 50,000 to 1,000,000.
[5] The optical laminate according to any one of [1] to [4], wherein the polyimide-based resin contains a fluorine atom.
[6] The optical laminate according to any one of [1] to [5], wherein the thickness of the resin film is 20 to 150 μm.
[7] The optical laminate according to any one of [1] to [6], wherein the first hard coat layer is a cured product of a curable composition containing a fluorine-containing compound.
[8] The optical laminate according to [7], wherein the content of the fluorine-containing compound contained in the curable composition is 0.1 to 5 parts by mass based on the mass of the solid content of the curable composition. body.
[9] The optical laminate according to any one of [1] to [8], wherein the thickness of the first hard coat layer and the thickness of the second hard coat layer are each 1 to 15 μm.
[10] The optical laminate according to any one of [1] to [9], wherein the ratio of the thickness of the first hard coat layer to the thickness of the second hard coat layer is 10: 7 to 7:10.
[11] The optical laminate according to any one of [1] to [10], which has a yellowness of 5.0 or less.
[12] The optical laminate according to any one of [1] to [11], wherein the total light transmittance is 80% or more.

  The optical laminate of the present invention is excellent in wiping properties of fingerprints and the like and bending resistance, and can exhibit excellent visibility.

FIG. 3 is a schematic cross-sectional view illustrating an example of a layer configuration in the optical laminate of the present invention.

  The optical laminate of the present invention includes a resin film containing a polyimide resin, a first hard coat layer laminated on one surface of the resin film, and a second hard coat layer laminated on the other surface. Having.

[Resin film]
The resin film contains a polyimide resin.

  In one embodiment of the present invention, the resin film is a film whose number of bending exceeds 100,000 times in a MIT bending fatigue test with a bending radius of 3 mm based on ASTM standard D2176-16. The number of times of bending can be measured in accordance with ASTM standard D2176-16, for example, by the method described in Examples.

In one embodiment of the present invention, the resin film is a film having an indentation hardness of 350 N / mm ² or more measured with a nano indenter in a cross section in the thickness direction. From the viewpoint of easily increasing the mechanical strength of the optical stack, the indentation hardness is preferably 400 N / mm ² or more, more preferably 450 N / mm ² or more, more preferably 500 N / mm ² or more, particularly preferably 550 N / mm ² or more. But not limited the upper limit of the indentation hardness in particular, from the viewpoint of easily improving the flex resistance, preferably 800 N / mm ² or less, more preferably 750 N / mm ^2, more preferably not more than 700 N / mm ^2. The indentation hardness is the indentation hardness in a cross section in the thickness direction measured using a nano indenter, and can be measured, for example, by the method described in Examples. When the number of bending times of the resin film exceeds 100,000 times or the indentation hardness is 350 N / mm ² or more, the resin film has sufficient bending resistance, so that even if the optical laminate is repeatedly bent, The resin film does not deteriorate, and peeling or deterioration of the interface between the resin film and the first hard coat layer or the second hard coat layer is suppressed, and the bending resistance and visibility of the optical laminate can be improved. When the optical laminate of the present invention is applied to an image display device, the first hard coat layer is on the viewing side (display unit side) of the image display device, and the second hard coat layer is on the side opposite to the viewing side. To place. Further, in the present specification, the visibility means the visibility of the display unit of the image display device when viewed visually (when the display unit is viewed from the viewing side).

The polyimide resin contained in the resin film means a polymer (polyimide, polyamide imide, polyamide) mainly containing a structural unit containing an imide group and a structural unit containing an amide group. Polyimide has a structural unit containing an imide group, polyamide imide has a structural unit containing an imide group and a structural unit containing an amide group, and polyamide has a structural unit containing an amide group. The kind of the polyimide resin is not particularly limited, and the number of bending times of the obtained resin film is more than 100,000, or the indentation hardness measured by using a nano indenter is 350 N / mm ² or more. The type of the repeating structural unit of the polyimide resin may be appropriately selected.

  In one embodiment of the present invention, the polyimide resin can be produced using, for example, a tetracarboxylic acid compound and a diamine compound as main raw materials, and the polyimide resin is a repeating resin represented by the following formula (10). It has a structural unit. In the formula (10), G is a tetravalent organic group, and A is a divalent organic group. In the present invention, the polyimide resin may include two or more types of structures represented by the formula (10) having different G and / or A.

  In addition, the polyimide resin may include one or more structures selected from the structures represented by Formulas (11) to (13) as long as various physical properties of the obtained resin film are not impaired. It is preferable that the polyimide resin is a polyamideimide further containing a repeating structural unit represented by the formula (13) from the viewpoint of easily improving the bending resistance.

In the formulas (10) and (11), G and G ¹ each independently represent a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. As G and G ¹ , Equation (20), Equation (21), Equation (22), Equation (23), Equation (24), Equation (25), Equation (26), Equation (27), and Equation (28) Or a group represented by the formula (29); a group in which a hydrogen atom in the group represented by the formula is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and a tetravalent carbon number 6 or less chain hydrocarbon groups are exemplified.

In the above formula, * represents a bond,
Z 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 It represents a _-Ar-SO 2 -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms which may be substituted by a fluorine atom, and specific examples include a phenylene group. From the viewpoint of easily improving the bending resistance of the obtained resin film, G ¹ is preferably a group represented by Formula (26), Formula (28), and Formula (29).

Wherein (12), G ² represents a trivalent organic radical, preferably a hydrogen atom in an organic group hydrocarbon group or fluorine-substituted hydrocarbon organic group which may be substituted with a group. The G ^2, equation (20), equation (21), equation (22), equation (23), equation (24), equation (25), equation (26), equation (27), equation (28) or Examples thereof include a group in which one of the bonding hands of the group represented by the formula (29) is replaced by a hydrogen atom, and a trivalent chain hydrocarbon group having 6 or less carbon atoms.

In the formula (13), G ³ represents a divalent organic group, and is preferably 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. As G ³ , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28), or Among the bonds of the group represented by the formula (29), a group in which two non-adjacent atoms are replaced by hydrogen atoms, and a chain hydrocarbon group having 6 or less carbon atoms are exemplified.

In the formulas (10) to (13), A, A ¹ , A ² and A ³ each independently represent a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms. . The organic group, a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, in which case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably Is 1 to 8.
As A, A ¹ , A ² and A ³ , formula (30), formula (31), formula (32), formula (33), formula (34), formula (35), formula (36), formula (36) 37) or a group represented by the formula (38); a group in which a hydrogen atom in the group represented by the formula is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; Are exemplified.

In the formulas (30) to (38), * represents a bond,
Z ^{1, Z 2} and ^{Z 3} are independently a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) 2 - _{, -C (CF 3) 2 -} , - representing the or -CO- - SO _2. The bonding position of each of Z ¹ and Z ² to each ring and the bonding position of each of Z ² and Z ³ to each ring are preferably meta-position or para-position with respect to each ring, and more preferably para-position. Rank.

［式（３）中、Ｒ^１〜Ｒ^８は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基又は炭素数６〜１２のアリール基を表し、Ｒ^１〜Ｒ^８に含まれる水素原子は、それぞれ独立に、ハロゲン原子で置換されていてもよく、
Ｂは、単結合、−Ｏ−、−ＣＨ_２−、−ＣＨ_２−ＣＨ_２−、−ＣＨ（ＣＨ_３）−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−Ｓ−、−ＣＯ−又は−Ｎ（Ｒ^９）−を表し、Ｒ^９は水素原子、ハロゲン原子で置換されていてもよい炭素数１〜１２の１価の炭化水素基を表し、
ｎは０〜４の整数であり、
＊は結合手を表す］
で表される構成単位であることが好ましい。 In one embodiment of the present invention, polyimide resin contained in the resin film may comprise a G ³ of a plurality of types, G ³ of plural kinds may being the same or different. In particular, from the viewpoint of improving the surface hardness and flexibility of the optical stack comprising a polyimide resin as a resin film, at least a part of G ^3, equation (3)

[In the formula (3), R ^{1 to} R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and hydrogen contained in R ^{1 to} R ⁸ The atoms may be each independently substituted with a halogen atom,
B represents a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, - C (CF 3) 2 -, - Represents SO ₂ —, —S—, —CO— or —N (R ⁹ ) —, wherein R ⁹ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. Represent
n is an integer from 0 to 4,
* Represents a bond]
It is preferable that the structural unit is represented by

In the formula (3), B is independently 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 preferably —O— or from the viewpoint of improving the bending resistance of the optical laminate. -S-, more preferably -O-. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Represent. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and 2-methyl-. Butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl and the like. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group. From the viewpoint of the surface hardness and flexibility of the optical laminate, R ^{1 to} R ⁸ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or 1 to 6 carbon atoms. 3 represents an alkyl group, 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 monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, 2-methyl-butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl, 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.

In the formula (3), n is an integer in the range of 0 to 4, and when n is within this range, the bending resistance and the elastic modulus of the optical laminate are good. In the formula (3), n is preferably an integer in the range of 0 to 3, more preferably an integer in the range of 0 to 2, and even more preferably 0 or 1, and when n is within this range, The flexibility and the elastic modulus of the optical laminate are good, and the availability of the raw materials is relatively good. G ³ may contain one or more kinds of structural units represented by the formula (3), and improve the elastic modulus and the bending resistance of the optical laminate and reduce the yellowness (YI value). In view of the above, in particular, two or more types of constituent units having different values of n, preferably two types of constituent units having different values of n may be included. In that case, it is preferable that n includes both 0 and 1 structural units from the viewpoint that the optical laminate easily exhibits high elastic modulus, bending resistance, and low yellowness (YI value).

で表される構成単位であり、これらは併用することもできる。この場合、光学積層体は、高い表面硬度を発揮すると同時に、高い耐屈曲性を有することができ、黄色度を低くすることができる。 In a preferred embodiment of the present invention, the formula (3) is a structural unit wherein m = 0 and R ^{1 to} R ⁸ are a hydrogen atom, or a formula (3 ′):

And these may be used in combination. In this case, the optical laminate exhibits high surface hardness, can have high bending resistance, and can reduce yellowness.

  In a preferred embodiment of the present invention, the formula (1) in which n is 0 to 4 with respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) of the polyimide resin. The content of the structural unit represented by 3) is preferably at least 20 mol%, more preferably at least 30 mol%, further preferably at least 40 mol%, particularly preferably at least 50 mol%, most preferably at least 60 mol%. It is preferably at least 90 mol%, more preferably at most 85 mol%, further preferably at most 80 mol%. The structural unit represented by the formula (3) when n is 0 to 4 with respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) in the polyimide resin. When the content of is equal to or more than the above lower limit, the optical laminate can exhibit high surface hardness and can have excellent bending resistance and elastic modulus. The structural unit represented by the formula (3) when n is 0 to 4 with respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) in the polyimide resin. When the content of is less than or equal to the above upper limit, the viscosity of the polyimide resin varnish can be suppressed by suppressing the viscosity increase due to the hydrogen bond between the amide bonds derived from the formula (3), and the processing of the resin film can be suppressed. Can be easier.

In a preferred embodiment of the present invention, n in the formula (3) is 1 to 4 with respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) of the polyimide resin. Is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 7 mol% or more, particularly preferably 9 mol% or more, and preferably 90 mol% or less. , More preferably at most 70 mol%, further preferably at most 50 mol%, particularly preferably at most 30 mol%. With respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) in the polyimide resin, the content of the structural unit represented by n in the formula (3) is represented by 1 to 4. When the amount is equal to or more than the above lower limit, the optical laminate can exhibit high surface hardness and bend resistance is further improved. With respect to the total of the structural unit represented by the formula (10) and the structural unit represented by the formula (13) in the polyimide resin, the structural unit in which n in the formula (3) is 1 to 4 is as described above. When the viscosity is equal to or less than the upper limit, the viscosity of the polyimide resin varnish can be suppressed by suppressing the viscosity increase due to the hydrogen bond between the amide bonds derived from the formula (3), and the processing of the resin film can be facilitated. it can. The content of the structural unit represented by the formula (3) can be measured using, for example, ¹ H-NMR, or can be calculated from the charge ratio of the raw materials.

In a preferred embodiment of the present invention, the G ³ of the polyimide-based resin, preferably 5 mol% or more, more preferably 8 mol% or more, more preferably 10 mol% or more, and particularly preferably at least 12 mol%, It is expressed by equation (3) when n is 1 to 4. Or above the lower limit of G ³ of polyimide resin is, when n is represented by the formula (3) in the case of 1-4, at the same time when the optical laminate exhibits high surface hardness, to have high flexibility Can be. Further, the ^{G 3} in the polyimide-based resin, preferably 90 mol% or less, 70 mole% and more preferably less, more preferably 50 mol% or less, particularly preferably 30 mol% or less, when n is 1 to 4 Is preferably represented by the following formula (3). The upper limit of G ³ of polyimide resin or less, when n is represented by the formula (3) in the case of 1-4, by n is formula (3) derived from the amide bond between a hydrogen bond in the case of 1-4 By suppressing the viscosity increase, the viscosity of the polyimide resin varnish can be suppressed, and the processing of the optical laminate can be facilitated.

In a preferred embodiment of the present invention, the G ³ of the polyimide-based resin, preferably 30 mol% or more, more preferably 50 mol% or more, particularly preferably 70 mol% or more, when n is 0-4 Expression (3). Or above the lower limit of G ³ of polyimide resin is, when n is represented by the formula (3) in the case of 0-4, the optical stack is at the same time as exhibiting high surface hardness has a high flexibility be able to. Further, the ^{G 3} in the polyimide-based resin, preferably 100 mol% or less, n is is preferably represented by the formula (3) in the case of 0-4. Above the upper limit of the polyimide-based resin G ³ or less, when n is represented by the formula (3) in the case of 0-4, the formula (3) when n is 0 to 4 from the amide bond between hydrogen By suppressing the increase in viscosity due to bonding, the viscosity of the polyimide resin varnish can be suppressed, and processing of the optical laminate can be facilitated. In addition, the ratio of the structural unit represented by the formula (3) in the polyimide resin can be measured using, for example, ¹ H-NMR, or can be calculated from the charging ratio of the raw materials.

［式（４）中、Ｒ^１０〜Ｒ^１７は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基又は炭素数６〜１２のアリール基を表し、Ｒ^１０〜Ｒ^１７に含まれる水素原子は、それぞれ独立に、ハロゲン原子で置換されていてもよく、＊は結合手を表す］
で表される構成単位である。式（１０）及び（１３）中の複数のＡ及びＡ^３の少なくとも一部が式（４）で表される基であると、光学積層体は、高い表面硬度を発現できると同時に、高い透明性を有することができる。 In a preferred embodiment of the present invention, at least a part of the plurality of A and A ³ in the formulas (10) and (13) is represented by the formula (4):

[In the formula (4), R ^{10 to} R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and hydrogen included in R ^{10 to} R ¹⁷ The atoms may be each independently substituted with a halogen atom, and * represents a bond.
Is a structural unit represented by When at least a part of the plurality of A and A ^{3 in} the formulas (10) and (13) is a group represented by the formula (4), the optical laminate can exhibit high surface hardness and at the same time have high transparency. Property.

In the 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 or a carbon atom having 6 carbon atoms. To 12 aryl groups. Examples of the alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms include those exemplified as the alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms in the formula (3). R ¹⁰ to R ¹⁷ are each independently preferably represents an alkyl group having 1 to 6 carbon hydrogen atom or atoms, more preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, ^{wherein, R 10} ~ The hydrogen atoms contained in R ¹⁷ may be each independently substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. R ^{10 to} R ¹⁷ are each independently preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, from the viewpoints of surface hardness, transparency and bending resistance of the optical laminate, Particularly preferably, R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are a hydrogen atom, and R ¹¹ and R ¹⁷ are a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group. Preferably, R ¹¹ and R ¹⁷ are a methyl group or a trifluoromethyl group.

で表される構成単位であり、すなわち、複数のＡ及びＡ^３の少なくとも一部は、式（４’）で表される構成単位である。この場合、光学積層体は、高い透明性を発現すると同時に、フッ素元素を含有する骨格により該ポリイミド系樹脂の溶媒への溶解性を向上し、ポリイミド系樹脂ワニスの粘度を低く抑制することができ、樹脂フィルムの加工を容易にすることができる。 In a preferred embodiment of the present invention, the structural unit represented by the formula (4) is a compound represented by the formula (4 ′):

In a structural unit represented by, i.e., at least a portion of the plurality of A and A ^3, a structural unit represented by formula (4 '). In this case, the optical laminate exhibits high transparency, and at the same time, improves the solubility of the polyimide-based resin in the solvent by the skeleton containing a fluorine element, and can suppress the viscosity of the polyimide-based resin varnish to be low. In addition, processing of the resin film can be facilitated.

In a preferred embodiment of the present invention, preferably 30 mol% or more, more preferably 50 mol% or more, even more preferably 70 mol% or more of A and A ³ in the above-mentioned polyimide-based resin is the formula (4), especially It is represented by equation (4 ′). When A and A ³ in the above range in the polyimide-based resin is represented by formula (4), particularly the formula (4 '), the optical stack, and at the same time exhibit high transparency, containing fluorine element skeleton Thereby, the solubility of the polyimide resin in a solvent can be improved, the viscosity of the polyimide resin varnish can be suppressed to a low level, and the processing of the resin film can be facilitated. Incidentally, preferably, 100 mole percent of A and ^{A 3} of the polyimide resin following Formula (4), in particular represented by the formula (4 '). A and A ³ of the polyimide resin of the formula (4), may be especially (4 '). The ratio of structural units represented by the formula of A and A ³ of the polyimide resin (4) can also be calculated from, for example, can be determined using ^{1 H-NMR,} or the raw material charging ratio of .

［式（５）中、Ｒ^１８〜Ｒ^２５は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基又は炭素数６〜１２のアリール基を表し、Ｒ^１８〜Ｒ^２５に含まれる水素原子は、それぞれ独立に、ハロゲン原子で置換されていてもよく、＊は結合手を表す］
で表される構成単位である。式（１０）中の複数のＧの少なくとも一部が式（５）で表される基であると、光学積層体は、高い透明性を発現すると同時に、ポリイミド系樹脂の溶媒への溶解性を向上し、ポリイミド系樹脂ワニスの粘度を低く抑制することができ、また樹脂フィルムの加工を容易にすることができる。 In a preferred embodiment of the present invention, at least a part of the plurality of Gs in the formula (10) is represented by the formula (5):

[In the formula (5), R ^{18 to} R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and hydrogen contained in R ^{18 to} R ²⁵ The atoms may be each independently substituted with a halogen atom, and * represents a bond.
Is a structural unit represented by When at least a part of the plurality of Gs in the formula (10) is a group represented by the formula (5), the optical laminate exhibits high transparency and at the same time, the solubility of the polyimide resin in the solvent is improved. Thus, the viscosity of the polyimide resin varnish can be suppressed to be low, and the processing of the resin film can be facilitated.

In the 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 or a carbon atom having 6 carbon atoms. -12 represents an aryl group. Examples of the alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms include those exemplified as the alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms in the formula (3). R ¹⁸ to R ²⁵ are each independently preferably represents an alkyl group having 1 to 6 carbon hydrogen atom or atoms, more preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, ^{wherein, R 18} ~ The hydrogen atoms contained in R ²⁵ may be each independently substituted with a halogen atom. 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 preferably hydrogen atom, methyl group, fluoro group, chloro group or trifluoromethyl, from the viewpoint of easily improving the surface hardness, flex resistance and transparency of the optical laminate. 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 It is preferable that R ²¹ and R ²² are a methyl group or a trifluoromethyl group.

で表される構成単位であり、すなわち、複数のＧの少なくとも一部は、式（５’）で表される構成単位である。この場合、光学積層体は、高い透明性を有することができる。 In a preferred embodiment of the present invention, the structural unit represented by the formula (5) is a compound represented by the formula (5 ′):

In other words, at least a part of the plurality of Gs is a structural unit represented by Formula (5 ′). In this case, the optical laminate can have high transparency.

In a preferred embodiment of the present invention, G in the polyimide resin is preferably at least 50 mol%, more preferably at least 60 mol%, and still more preferably at least 70 mol% of the formula (5), particularly the formula (5) '). When G in the above range of the polyimide-based resin is represented by the formula (5), particularly the formula (5 ′), the optical laminate can have high transparency, and further has a skeleton containing a fluorine element. The solubility of the polyimide resin in the solvent can be improved, the viscosity of the polyimide resin varnish can be suppressed to a low level, and the production of the optical laminate is easy. Preferably, 100 mol% or less of G in the polyimide resin is represented by the formula (5), particularly the formula (5 ′). G in the polyimide resin may be represented by the formula (5), particularly (5 ′). The ratio of the structural unit of G represented by the formula (5) in the polyimide-based resin can be measured, for example, using ¹ H-NMR, or can be calculated from the charging ratio of the raw materials.

  The polyimide-based resin can be obtained, for example, by polycondensation of a diamine compound and a tetracarboxylic acid compound (such as tetracarboxylic dianhydride), for example, JP-A-2006-199945 or JP-A-2008-163107. Can be synthesized according to the method described in Commercially available polyimides include Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc., and KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd.

  In a preferred embodiment of the present invention, the polyimide having a repeating structural unit represented by the formula (10) can be obtained by reacting a diamine compound with a tetracarboxylic acid compound, and represented by the formula (10). Having a repeating structural unit represented by the formula (13) and a repeating structural unit represented by the formula (13) can be obtained by reacting a diamine compound with a tetracarboxylic acid compound and then further reacting a dicarboxylic acid compound. The polyamide having a repeating structural unit represented by the formula (13) can be obtained by reacting a diamine compound with a dicarboxylic acid compound.

  Examples of the tetracarboxylic acid compound used in the synthesis of the polyimide resin include aromatic tetracarboxylic acids and anhydrides thereof, preferably aromatic tetracarboxylic acid compounds such as dianhydrides; aliphatic tetracarboxylic acids and anhydrides thereof; Preferably, an aliphatic tetracarboxylic acid compound such as dianhydride is exemplified. The tetracarboxylic acid compound may be a derivative of a tetracarboxylic acid compound such as an acid chloride in addition to an anhydride, and these may be used alone or in combination of two or more.

Specific examples of the aromatic tetracarboxylic dianhydride include a non-condensed polycyclic aromatic tetracarboxylic dianhydride, a monocyclic aromatic tetracarboxylic dianhydride and a condensed polycyclic aromatic tetracarboxylic acid. Carboxylic dianhydrides are mentioned. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 2,2 ′ , 3,3'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (also referred to as BPDA), 2,2', 3,3 ' -Biphenyltetracarboxylic 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 Anhydride (6F A), 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, 4,4 ′-(p-phenylenedioxy) diphthalic dianhydride, 4,4 ′-(m-phenylenedioxy) diphthalic dianhydride Is mentioned. Further, examples of the monocyclic aromatic tetracarboxylic dianhydride include 1,2,4,5-benzenetetracarboxylic dianhydride, and as a condensed polycyclic aromatic tetracarboxylic dianhydride, Is 2,3,6,7-naphthalenetetracarboxylic dianhydride.
Among these, 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and 2,2 ′, 3,3′-benzophenonetetracarboxylic dianhydride are preferred. Anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyl Sulfonetetracarboxylic 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 dianhydride, 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride Thing, 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, 4,4 ′-(p-phenylenedioxy) diphthalic dianhydride And 4,4 '-(m-phenylenedioxy) diphthalic dianhydride. These can be used alone or in combination of two or more.

  Examples of the aliphatic tetracarboxylic dianhydride include cyclic and acyclic aliphatic tetracarboxylic dianhydrides. The cycloaliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride. A cycloalkanetetracarboxylic dianhydride such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 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. These can be used alone or in combination of two or more. Further, a combination of a cycloaliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride may be used.

  Among the tetracarboxylic acid compounds, the alicyclic tetracarboxylic dianhydride or the non-condensed polycyclic aromatic tetracarboxylic dianhydride is preferably used from the viewpoint of high transparency and low coloring property. Specific examples include 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-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-di Preference is given to (carboxyphenyl) propane dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride and mixtures thereof.

  In the present invention, the polyimide-based resin, in addition to the tetracarboxylic acid compound used in the above-mentioned polyimide synthesis, as far as the various physical properties of the obtained transparent resin film are not impaired, is further combined with a tricarboxylic acid compound and a dicarboxylic acid compound. May be used.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and derivatives thereof (for example, acid chloride, acid anhydride, and the like). Specific examples thereof include 1,2,4-benzenetricarboxylic acid. anhydride; 2,3,6-naphthalene tricarboxylic acid-2,3-anhydride; and phthalic anhydride and benzoic acid is a single _{bond, -O -, - CH 2 -} , - C (CH 3) 2 -, Compounds linked by —C (CF ₃ ) ₂ —, —SO ₂ — or a phenylene group are exemplified. These tricarboxylic acid compounds can be used alone or in combination of two or more.

Examples of the dicarboxylic acid compound include an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and derivatives thereof (for example, acid chloride, acid anhydride, and the like). Specific examples thereof include terephthalic acid; isophthalic acid; and 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 having a single bond, —O—, —CH _{2 -, - C (CH 3)} 2 -, - C (CF 3) 2 -, - SO 2 - or a compound linked by a phenylene group, and their acid chlorides compounds. Among these dicarboxylic acid compounds, 4,4′-oxybisbenzoic acid and their acid chlorides are preferred, and terephthaloyl chloride and 4,4′-oxybis (benzoyl chloride) are more preferred. These dicarboxylic acid compounds can be used alone or in combination of two or more.

  The diamine compound used in the synthesis of the polyimide resin may be an aliphatic diamine, an aromatic diamine, or a mixture thereof. In this specification, the term "aromatic diamine" refers to a diamine compound in which an amino group is directly bonded to an aromatic ring, and may have an aliphatic group or another substituent in a part of its structure. . The aromatic ring may be a single ring or a condensed ring, and is exemplified by, but not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring. Among these, a benzene ring is preferred. The “aliphatic diamine” refers to a diamine compound in which an amino group is directly bonded to an aliphatic group, and a part of the structure may include an aromatic ring or another substituent.

  Examples of the aliphatic diamine include acyclic aliphatic diamines such as hexamethylene diamine and 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, norbornanediamine, and 4,4′-diamine. Cycloaliphatic diamines such as diaminodicyclohexylmethane and the like can be mentioned, and these can be used alone or in combination of two or more.

  Specific examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, and 2,6-diamino Aromatic diamine having one aromatic ring such as naphthalene; 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'-diaminodiphenylsulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-diaminodiphe Sulfone, 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 (also 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-chlorophenyl) fluorene, 9,9-bis (4-amino-3-fluorophenyl) fluorene, etc. Aromatic diamine having the like. These can be used alone or in combination of two or more.

  Among the above diamine compounds, it is preferable to use at least one selected from the group consisting of aromatic diamines having a biphenyl structure from the viewpoint of high transparency and low coloring property.

  The polyimide resin includes a diamine compound, a tetracarboxylic acid compound (an acid chloride compound, a tetracarboxylic acid compound derivative such as tetracarboxylic dianhydride), and optionally a tricarboxylic acid compound (an acid chloride compound, a tricarboxylic anhydride). Etc.) and a dicarboxylic acid compound (a dicarboxylic acid compound derivative such as an acid chloride compound) with at least one compound selected from the group consisting of polycondensation products. The repeating structural unit represented by the formula (11) is usually derived from a diamine compound and a tetracarboxylic acid compound. The repeating structural unit represented by the formula (12) is usually derived from a diamine compound and a tricarboxylic acid compound. The repeating structural unit represented by the formula (13) is usually derived from a diamine compound and a dicarboxylic acid compound. Specific examples of the diamine compound, tetracarboxylic acid compound, dicarboxylic acid compound, and tricarboxylic acid compound are as described above.

  The polyimide resin may be a copolymer containing a plurality of different types of the above repeating structural units. The weight average molecular weight of the polyimide resin is preferably 50,000 or more, more preferably 100,000 or more, further preferably 200,000 or more, particularly preferably 300,000 or more, and preferably 1,000,000 or less. , More preferably 750,000 or less, further preferably 600,000 or less, particularly preferably 500,000 or less. When the weight-average molecular weight of the polyimide-based resin is at least the lower limit described above, the bending resistance of the resin film containing the polyimide-based resin is improved, and even when the optical laminate is repeatedly bent, excellent visibility is exhibited. It's easy to do. In addition, when the weight average molecular weight of the polyimide resin is equal to or less than the above upper limit, the viscosity of the polyimide resin varnish can be suppressed to a low level, and since the resin film is easily formed, the processability is good. Become. In the present specification, the weight average molecular weight can be determined, for example, by performing GPC measurement and converting it into standard polystyrene, and specifically, it can be determined by the method described in Examples.

  The polyimide-based resin preferably contains a halogen atom, preferably a fluorine atom, which can be introduced by the above-mentioned halogen-based substituent. When the polyimide-based resin contains a halogen atom, particularly a fluorine atom, the degree of yellowness can be reduced while increasing the bending resistance of the resin film, so that the visibility of the optical laminate is easily improved.

  The content of halogen atoms in the polyimide-based resin is reduced in yellowness of the optical laminate, that is, from the viewpoint of improving transparency and easily expressing excellent visibility, from the viewpoint of easily expressing excellent visibility, the mass of the polyimide-based resin is 1 to 1. Preferably, it is 40% by mass.

  In the present invention, the content of the polyimide resin contained in the resin film is preferably 40% by mass or more, more preferably 60% by mass or more, and still more preferably 80% by mass or more, based on the mass of the resin film. It may be 100% by mass. When the content of the polyimide-based resin is equal to or more than the above lower limit, the resin film has good bending resistance, and easily exhibits excellent visibility even when the optical laminate is repeatedly bent.

  When the polyimide resin is a polyamideimide, the content of the structural unit represented by the formula (13) is preferably 0.1 mol or more, more preferably 1 mol or more, per 1 mol of the structural unit represented by the formula (10). It is preferably at least 0.5 mol, more preferably at least 1.0 mol, particularly preferably at least 1.5 mol, preferably at most 6.0 mol, more preferably at most 5.0 mol, even more preferably at least 4.0 mol. 5 mol or less. When the content of the structural unit represented by the formula (13) is equal to or greater than the lower limit, the optical laminate can exhibit higher surface hardness. When the content of the structural unit represented by the formula (13) is equal to or less than the above upper limit, the viscosity increase due to the hydrogen bond between the amide bonds in the formula (13) is suppressed, and the viscosity of the polyimide resin varnish is reduced. It can be reduced, and the production of the optical laminate is easy.

  The resin film contained in the optical laminate of the present invention can contain inorganic particles, particularly silica particles. The surface of the silica particles may be modified with an organic group. The average primary particle diameter of the silica particles is preferably at least 5 nm, more preferably at least 10 nm, further preferably at least 15 nm, particularly preferably at least 20 nm, preferably at most 100 nm, more preferably at most 80 nm, further preferably at most 60 nm. And particularly preferably 40 nm or less. When the average primary particle diameter of the silica particles is within the above range, aggregation of the silica particles is suppressed and the yellowness of the resin film is reduced, so that the visibility is easily improved. In the present invention, the average primary particle diameter can be measured by a BET method.

  The content of the silica particles is usually 0.1% by mass, preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, particularly preferably 30% by mass, based on the mass of the resin film. %, Preferably 60% by mass or less. When the content of the silica particles is equal to or more than the above lower limit, the bending resistance is more easily improved, and when the content of the silica particles is equal to or less than the above upper limit, the optical characteristics are improved, for example, the yellowness is reduced. It will be easier. Therefore, when the content is within the above range, excellent visibility is easily exhibited even when the optical laminate is repeatedly bent.

  The resin film contained in the optical laminate of the present invention may further contain an ultraviolet absorber. Examples of the ultraviolet absorber include a triazine-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a benzoate-based ultraviolet absorber, and a cyanoacrylate-based ultraviolet absorber. These may be used alone or in combination of two or more. Suitable commercially available ultraviolet absorbers include, for example, Sumisorb (registered trademark) 340 manufactured by Sumika Chemtex Co., Ltd., ADK STAB (registered trademark) LA-31 manufactured by ADEKA, and BASF Japan Co., Ltd. Tinuvin (registered trademark) 1577 and the like. When an ultraviolet absorber is contained, the deterioration of the resin film is suppressed, so that the optical characteristics of the optical laminate are easily enhanced. The content of the ultraviolet absorber is preferably 1 to 10% by mass, more preferably 3 to 8% by mass, based on the mass of the resin film. When the content of the ultraviolet absorber is in the above range, the optical characteristics of the resin film can be more easily improved.

  The optical film of the present invention may further contain a coloring agent. The content of the colorant can be appropriately selected according to the purpose, the type of the colorant, and the like. When a bluing agent is used as a coloring agent, its content is preferably 0.01 ppm or more, more preferably 0.1 ppm or more, still more preferably 1 ppm or more, and preferably 100 ppm or less, based on the mass of the resin film. , More preferably 50 ppm or less. As the bluing agent, known agents can be used as appropriate. For example, Macrolex (registered trademark) Blue RR (manufactured by Bayer), Macrolex Blue 3R (manufactured by Bayer), Sumiplast (registered trademark) can be used, respectively. Vilet B (manufactured by Sumika Chemtex Co., Ltd.) and Polycinthrene (registered trademark) Blue RLS (manufactured by Clariant), Diaresin Violet D, Diaresin Blue G, and Diaresin Blue N (all manufactured by Mitsubishi Chemical Corporation). Can be

The resin film may contain other additives in addition to the inorganic particles, the ultraviolet absorber and the colorant as long as the effects of the present invention are not impaired. Other additives include, for example, release agents, stabilizers, flame retardants, lubricants, leveling agents, and resins other than polyimide resins. When the resin film contains other additives, the content of the other additives is preferably about 0.01 to 20% by mass, more preferably about 0.1 to 10% by mass, based on the mass of the resin film. is there. By adjusting the type and content of the polyimide resin and / or the type and content of the additive, the number of bending times of the resin film is adjusted to more than 100,000 times or the indentation hardness is adjusted to 350 N / mm ² or more. Is also good.

  The thickness of the resin film is appropriately adjusted depending on the application, but is preferably 20 to 150 μm, more preferably 25 to 100 μm, and further preferably 30 to 90 μm. In the present invention, the thickness of the resin film can be measured by the method described in Examples.

[First hard coat layer]
In the optical laminate of the present invention, the first hard coat layer is laminated on one surface of the resin film, and the oleic acid contact angle on the surface of the layer is 65 ° or more. For this reason, the optical laminate of the present invention has excellent wiping properties against stains such as fingerprints that adhere when a user touches the surface of the first hard coat layer. In the present specification, the wiping property refers to whether or not a predetermined amount of dirt such as fingerprints can be wiped by reciprocating wiping using a test paper for wiping such as a tissue paper. Means that dirt such as fingerprints can be wiped off by reciprocating wiping about 1 to 4 times using a wiping test paper.
As described above, the optical laminate of the present invention is excellent in the wiping property of the surface of the first hard coat layer disposed on the viewing side of the image display device, and easily remains on the display portion even when stains such as fingerprints adhere. Since it can be wiped off, excellent visibility can be exhibited.

  The contact angle of oleic acid on the surface of the first hard coat layer is preferably 70 ° or more, more preferably 75 ° or more. When the oleic acid contact angle is equal to or more than the above lower limit, the wiping properties of fingerprints and the like are enhanced, and the visibility is further improved.

  The first hard coat layer is not particularly limited as long as the oleic acid contact angle on the layer surface is 65 ° or more, but the curable composition containing the curable compound (the curable composition (X) may be used). Is preferable).

  In the optical laminate of the present invention, the curable composition (X) constituting the first hard coat layer is a curable compound from the viewpoint of easily increasing the transparency, surface hardness, flex resistance and visibility of the optical laminate. Preferably contains a polyfunctional (meth) acrylate compound.

The polyfunctional (meth) acrylate compound means a compound having two or more (meth) acryloyloxy groups in a molecule. Here, in this specification, the term “(meth) acrylate” means “acrylate” or “methacrylate”, and the term “(meth) acryloyl” also means “acryloyl” or “methacryloyl”. .
The polyfunctional (meth) acrylate compound may contain one or more polyfunctional (meth) acrylate compounds. When two or more polyfunctional (meth) acrylate compounds are contained, the number of (meth) acryloyloxy groups may be the same or different between the respective polyfunctional (meth) acrylate compounds.

  Examples of the polyfunctional (meth) acrylate compound include a bifunctional (meth) acrylate monomer, a trifunctional (meth) acrylate monomer, a tetrafunctional (meth) acrylate monomer, a pentafunctional or higher (meth) acrylate monomer, and a urethane (meth) acrylate Oligomer, polyester (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, and the like. These polyfunctional (meth) acrylate compounds can be used alone or in combination of two or more. These monomers can be used in combination within a range that does not impair the effects of the present invention. For example, the bifunctional monomer and the trifunctional monomer, the bifunctional monomer and the tetrafunctional monomer, and the trifunctional And the tetrafunctional monomer, the difunctional monomer, the trifunctional monomer, the tetrafunctional monomer, and the pentafunctional or higher monomer.

  The bifunctional (meth) acrylate monomer is a monomer having two (meth) acryloyloxy groups in the molecule, for example, ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) Alkylene glycols such as acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate and neopentyl glycol di (meth) acrylate Di (meth) acrylate; diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acryle Polyoxyalkylene glycol di (meth) acrylates such as polypropylene glycol di (meth) acrylate and polytetramethylene glycol di (meth) acrylate; and halogenated alkylene glycol di (meth) acrylates such as tetrafluoroethylene glycol di (meth) acrylate. A) acrylates; di (meth) acrylates of aliphatic polyols such as trimethylolpropane di (meth) acrylate, ditrimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate; hydrogenated dicyclopentadienyl di (meth) A) di (meth) acrylates of hydrogenated dicyclopentadiene or tricyclodecane dialkanol such as acrylate, tricyclodecane dimethanol di (meth) acrylate; 1,3-dioxa Dioxane glycol or dioxane dialkanol di (meth) acrylate such as -2,5-diyldi (meth) acrylate [alias: dioxane glycol di (meth) acrylate]; bisphenol A ethylene oxide adduct diacrylate, bisphenol F ethylene oxide Di (meth) acrylate of an alkylene oxide adduct of bisphenol A or bisphenol F such as an adduct diacrylate; bisphenol A such as an acrylic acid adduct of bisphenol A diglycidyl ether, an acrylic acid adduct of bisphenol F diglycidyl ether, or Epoxy di (meth) acrylate of bisphenol F; silicone di (meth) acrylate; di (meth) acrylate of neopentyl glycol hydroxypivalate 2,2-bis [4- (meth) acryloyloxyethoxyethoxyphenyl] propane; 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane; 2- (2-hydroxy-1,1 -Dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane], and tris (hydroxyethyl) isocyanurate di (meth) acrylate.

  The trifunctional (meth) acrylate monomer is a monomer having three (meth) acryloyloxy groups in a molecule, and examples thereof include glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylol. Propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, reaction product of pentaerythritol tri (meth) acrylate and acid anhydride, caprolactone-modified trimethylolpropane tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate And isocyanurate tri (meth) acrylate, a reaction product of caprolactone-modified pentaerythritol tri (meth) acrylate and an acid anhydride, and the like. Among these, trimethylolpropane tri (meth) acrylate is preferred from the viewpoint of easily increasing the transparency, surface hardness, bending resistance, and visibility of the optical laminate of the present invention. These trifunctional (meth) acrylate monomers can be used alone or in combination of two or more.

  The tetrafunctional (meth) acrylate monomer is a monomer having four (meth) acryloyloxy groups in the molecule, and examples thereof include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, Examples include pentaerythritol tetra (meth) acrylate, tripentaerythritol tetra (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, and caprolactone-modified tripentaerythritol tetra (meth) acrylate. Among these, pentaerythritol tetra (meth) acrylate is preferred from the viewpoint of easily increasing the transparency, surface hardness, flex resistance and visibility of the optical laminate of the present invention. These tetrafunctional (meth) acrylate monomers can be used alone or in combination of two or more.

  Examples of the (meth) acrylate monomer having five or more functional groups include dipentaerythritol penta (meth) acrylate, tripentaerythritol penta (meth) acrylate, a reaction product of dipentaerythritol penta (meth) acrylate with an acid anhydride, and caprolactone modification. Pentafunctional (meth) acrylate monomers such as dipentaerythritol penta (meth) acrylate, caprolactone-modified tripentaerythritol penta (meth) acrylate, and a reaction product of caprolactone-modified dipentaerythritol penta (meth) acrylate with an acid anhydride; dipenta Erythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, cap Hexafunctional (meth) acrylate monomers such as lactone-modified tripentaerythritol hexa (meth) acrylate; reaction products of tripentaerythritol hepta (meth) acrylate and tripentaerythritol hepta (meth) acrylate with acid anhydride; caprolactone-modified tripentane 7-functional (meth) acrylate monomers such as erythritol hepta (meth) acrylate, a reaction product of caprolactone-modified tripentaerythritol hepta (meth) acrylate with an acid anhydride; tripentaerythritol octa (meth) acrylate, caprolactone-modified tripentaerythritol octa An octafunctional (meth) acrylate monomer such as (meth) acrylate is exemplified. These pentafunctional or higher functional (meth) acrylate monomers can be used alone or in combination of two or more.

  In a preferred embodiment of the present invention, from the viewpoint that the transparency, surface hardness, bending resistance and visibility of the optical laminate of the present invention are easily increased, the polyfunctional (meth) acrylate compound is the tetrafunctional (meth) acrylate monomer And the trifunctional (meth) acrylate monomer. In this case, the content of the trifunctional (meth) acrylate monomer is preferably 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, based on 1 part by mass of the tetrafunctional (meth) acrylate monomer. It is preferably from 0.5 to 1.5 parts by mass, particularly preferably from 0.9 to 1.1 parts by mass. When the content of the tetrafunctional (meth) acrylate monomer relative to the content of the trifunctional (meth) acrylate monomer is within the above range, the transparency, surface hardness, bending resistance, and visibility of the optical laminate are easily increased.

  In the curable composition (X) constituting the first hard coat layer, the content of the polyfunctional (meth) acrylate compound is preferably 50 parts by mass or more based on 100 parts by mass of the solid content of the curable composition. is there. When the content of the polyfunctional (meth) acrylate monomer is in the above range, the transparency, surface hardness, and visibility of the optical laminate are more easily improved. In addition, in this specification, when the curable composition contains a solvent, the solid content of the curable composition means a composition obtained by removing the solvent from the curable composition.

The curable composition (X) constituting the first hard coat layer preferably contains a surface conditioner for lowering the surface tension of the first hard coat layer, and particularly preferably a fluorine-containing compound as the surface conditioner. The surface conditioner is also called a leveling agent, an antifoaming agent, a surfactant, or a surface tension adjuster depending on its function. The oleic acid contact angle on the surface of the first hard coat layer can be made 65 ° or more by adjusting the type and content of the fluorine-containing compound. Usually, the larger the content of the fluorine-containing compound, the larger the oleic acid contact angle tends to be.
The oleic acid contact angle can be adjusted to 65 ° or more by adjusting the type and content of other components contained in the curable composition (X). Can be obtained.

  When the curable composition (X) constituting the first hard coat layer contains a fluorine compound, it is easy to improve the wiping properties such as fingerprints on the surface of the first hard coat layer, and the surface of the first hard coat layer is smoothed. Thus, the surface can have good slipperiness. Furthermore, the curable composition (X) has high wettability to a substrate, and can prevent the occurrence of coating film defects such as repelling and unevenness in a coating film formed by applying the curable composition (X). This is advantageous in terms of the bending resistance of the optical laminate including the first hard coat layer.

  As the fluorine-containing compound, a compound having an alkyl group in which at least a part of a hydrogen atom is substituted with a fluorine atom (sometimes referred to as a fluorinated alkyl group-containing compound) or a compound in which at least a part of a hydrogen atom is substituted with a fluorine atom Compounds having an alkenyl group (sometimes referred to as fluorinated alkenyl group-containing compounds) and the like. The fluorine containing compound may be a monomer, oligomer or polymer. These fluorine-containing compounds can be used alone or in combination of two or more.

  Specific examples of the fluorine-containing compound include, for example, “BYK (registered trademark) -340” manufactured by Big Chemie Japan; and “Fantagent” (registered trademark) “222F”, “601AD”, “601ADH2”, and “650AC” manufactured by Neos. "; MegaFac (registered trademark)“ R-08 ”,“ R-30 ”,“ R-90 ”,“ F-410 ”,“ F-411 ”,“ F-443 ”, manufactured by DIC Corporation; “F-445”, “F-470”, “F-471”, “F-577”, “F-479”, “F-482”, “F-483”; manufactured by AGC Seimi Chemical Co., Ltd. Surflon (registered trademark) "S-381", "S-382", "S-383", "S-393", "SC-101", "SC-105", "KH-40", "SA-" 100 ”; Mitsubishi Materials Electronic Chemical Co., Ltd. Top (registered trademark) EF301, “Ftop EF303”, “Ftop EF351”, “Ftop EF352”; “V-8FM” manufactured by Osaka Organic Chemical Industry Co., Ltd., “Optool manufactured by Daikin Industries, Ltd.” (Registered trademark) DAC ". These fluorine-containing compounds can be used alone or in combination of two or more.

  When the curable composition (X) constituting the first hard coat layer contains a fluorine-containing compound, the content of the fluorine-containing compound is preferably 0 with respect to the mass of the solid content of the curable composition (X). 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, still more preferably 0.3 parts by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and still more preferably 3 parts by mass or less. It is. When the content of the fluorine-containing compound is at least the lower limit described above, it is easy to improve the wiping properties of fingerprints and the like on the surface of the first hard coat layer, the antifouling property, the smoothness, and the bending resistance of the optical laminate. When the content of the fluorine-containing compound is equal to or less than the above upper limit, the bending resistance of the optical laminate is easily improved.

  The curable composition (X) constituting the first hard coat layer may include a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it can initiate curing of the curable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams. Specific examples thereof include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane Acetophenone-based initiators such as -1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4,4'-diaminobenzophenone; , 2-Dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl Alkylphenone initiators such as phenyl-ketone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; bis (2,4,6-trimethylbenzoyl) -phenyl Acylphosphine oxide-based initiators such as phosphine oxide; and others, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like. These photopolymerization initiators can be used alone or in combination of two or more. Among these photopolymerization initiators, an alkylphenone-based initiator and an acylphosphine oxide-based initiator are preferred. The photopolymerization initiators can be used alone or in combination of two or more.

  When the curable composition (X) contains a photopolymerization initiator, the content of the photopolymerization initiator is preferably from 0.1 to 10 parts by mass, more preferably from 100 parts by mass of the total amount of the curable compound. It is 0.5 to 7 parts by mass, more preferably 1 to 5 parts by mass. When the content of the photopolymerization initiator is not less than the above lower limit, the polymerization initiation ability is sufficiently exhibited, and the curability is improved. On the other hand, when the content of the polymerization initiator is equal to or less than the above upper limit, the photopolymerization initiator hardly remains, and it is easy to suppress a decrease in visible light transmittance and the like.

  The curable composition (X) constituting the first hard coat layer contains, as necessary, additives other than the polyfunctional (meth) acrylate compound, the fluorine-containing compound, and the photopolymerization initiator. Good. Other additives include, for example, monofunctional (meth) acrylate compounds, polyfunctional urethane acrylate monomers and inorganic particles such as silica particles described in the section of polymer [resin film], ultraviolet absorbers, antistatic agents, and stabilizing agents. Agents, antioxidants, coloring agents, and surface modifiers that do not contain fluorine atoms described below. The additives can be used alone or in combination of two or more. The content of the additive is preferably about 0.01 to 20% by mass based on the mass of the solid content of the curable composition.

  The curable composition (X) constituting the first hard coat layer may further contain a solvent for coating on the resin film. 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. Esters such as ethyl acetate, butyl acetate, and isobutyl acetate; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; ethylene glycol monomethyl ether Acetate, propylene glycol monomethyl ether Acetate and other esterified glycol ethers and the like are appropriately selected and used. It is possible. These solvents can be used alone or in combination of two or more. The type and content of the solvent are appropriately selected according to the type and content of the components contained in the curable composition, the material and shape of the resin film, the coating method, the thickness of the first hard coat layer, and the like. The content of the solvent is about 10 to 10,000 parts by weight, preferably about 20 to 1,000 parts by weight, more preferably about 20 to 100 parts by weight, based on 100 parts by weight of the total amount of the components contained in the curable composition. It may be.

  The curable composition (X) constituting the first hard coat layer includes, for example, the polyfunctional (meth) acrylate compound, the fluorine-containing compound, the photopolymerization initiator, the solvent, and the other additive if necessary. It is obtained by mixing the agents by a conventional method, for example, stirring. The order of mixing these is not particularly limited.

  The first hard coat layer is obtained by curing the curable composition (X). The thickness of the first hard coat layer is preferably 1 to 15 μm, more preferably 2 to 10 μm. When the thickness of the first hard coat layer is within the above range, the bending resistance of the optical laminate is improved, and even when the optical laminate is repeatedly bent, excellent visibility is easily exhibited and the surface hardness is also improved. Easy to be improved.

[Second hard coat layer]
In the optical laminate of the present invention, the second hard coat layer is laminated on the surface of the resin film opposite to the first hard coat layer, and the oleic acid contact angle on the layer surface is 1 ° or more and less than 65 °. is there. Therefore, when the optical laminate is disposed on a polarizing plate or the like via an adhesive, the adhesiveness with the adhesive is excellent, and even when bending is repeatedly performed, the interface between the second hard coat layer and the adhesive is peeled off. It can be effectively suppressed, and excellent visibility can be exhibited.

  The oleic acid contact angle on the surface of the second hard coat layer is preferably 1 to 60 °, more preferably 5 to 45 °, and further preferably 10 to 40 °. When the oleic acid contact angle of the second hard coat layer is within the above range, the adhesion to the pressure-sensitive adhesive is further improved, and more excellent visibility can be exhibited.

  The second hard coat layer is not particularly limited as long as the oleic acid contact angle on the layer surface is 10 ° or more and less than 65 °, but the curable composition containing the curable compound (curable composition (Y) In some cases).

  In the optical laminate of the present invention, the curable composition (Y) constituting the second hard coat layer is a multi-component curable compound from the viewpoint of easily increasing the transparency, bending resistance, and visibility of the optical laminate. It is preferable to include a functional (meth) acrylate compound. Examples of the polyfunctional (meth) acrylate compound include the same as the polyfunctional (meth) acrylate compound exemplified in the section of [First Hard Coat Layer], and preferred polyfunctional (meth) acrylate compounds, combinations thereof, and polyfunctional (meth) acrylate compounds. The same applies to the range of the ratio of the functional (meth) acrylate compound.

  The curable composition (Y) constituting the second hard coat layer may contain the fluorine-containing compound described in the section of [First Hard Coat Layer], but the oleic acid contact on the surface of the second hard coat layer From the viewpoint that the angle can be easily adjusted to 1 ° or more and less than 65 °, it is preferable to include a surface conditioner containing no fluorine atom. Examples of such a surface conditioner include a polysiloxane compound and a poly (meth) acrylate compound. The polysiloxane compound is a compound having a polysiloxane skeleton in the main chain, and the poly (meth) acrylate compound is a (meth) acrylic polymer or copolymer. These surface conditioners can be used alone or in combination of two or more. By adjusting the type and content of the surface conditioner and the type and content of other components contained in the curable composition (Y), the oleic acid contact angle is in the range of 1 ° or more and less than 65 °. Can be adjusted. The oleic acid contact angle can be adjusted to 1 ° or more and less than 65 ° by adjusting the type and content of other components contained in the curable composition (Y). The effects of the invention can be obtained.

  A surface conditioner such as a polysiloxane compound and a poly (meth) acrylate compound enhances the wettability of the curable composition (Y) to a substrate, and a coating film formed by applying the curable composition (Y) In this case, the occurrence of coating defects such as repelling and unevenness can be prevented, which is advantageous in terms of the bending resistance of the optical laminate including the second hard coat layer. Further, the surface conditioner such as a polysiloxane compound and a poly (meth) acrylate compound also enhances the wettability of the surface of the second hard coat layer, so that when the optical laminate is disposed on a polarizing plate or the like via an adhesive, Adhesion between the second hard coat layer and the adhesive can be improved. Therefore, even if bending is repeatedly performed, peeling of the interface between the second hard coat layer and the adhesive can be effectively suppressed, and excellent visibility is easily developed.

［式（４１）中、Ｒ^４１〜Ｒ^４９は、それぞれ独立に、炭素数１〜２０のアルキル基を表し、Ｌ^４１は炭素数１〜２０のアラルキル基、（メタ）アクリロイル基、ヒドロキシル基、カルボキシル基、メルカプト基、アミノ基、エポキシ基、ポリエーテル構造部位、又はポリエステル構造部位を表し、ａ及びｂはそれぞれ１以上の任意の整数であり、ａ又はｂが２以上の整数である場合、Ｒ^４５、Ｌ^４１、Ｒ^４６及びＲ^４１はそれぞれ同一でも異なっていてもよく、［（Ｒ^４５）（Ｌ^４１）ＳｉＯ］単位及び［（Ｒ^４６）（Ｒ^４１）ＳｉＯ］単位のポリシロキサン化合物の構造中での配置は任意である］
で表されるポリシロキサン化合物が挙げられる。 As the polysiloxane compound, for example, the formula (41)

[In formula (41), R ^{41 to} R ⁴⁹ each independently represent an alkyl group having 1 to 20 carbon atoms, and L ⁴¹ represents an aralkyl group having 1 to 20 carbon atoms, a (meth) acryloyl group, a hydroxyl group, A carboxyl group, a mercapto group, an amino group, an epoxy group, a polyether structure site, or a polyester structure site, and a and b are each an integer of 1 or more, and when a or b is an integer of 2 or more, R ⁴⁵ , L ⁴¹ , R ⁴⁶ and R ⁴¹ may be the same or different, respectively, and are polysiloxane compounds of [(R ⁴⁵ ) (L ⁴¹ ) SiO] units and [(R ⁴⁶ ) (R ⁴¹ ) SiO] units. The arrangement in the structure is arbitrary.]
The polysiloxane compound represented by these is mentioned.

In the formula (41), examples of the alkyl group having 1 to 20 carbon atoms of R ^{41 to} R ⁴⁹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. Pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and the like. Among these, a methyl group, an ethyl group, or the like is preferable as the alkyl group having 1 to 20 carbon atoms of R ^{42 to} R ⁴⁹ , and a methyl group, an ethyl group, and a decyl group are preferable as the alkyl group having 1 to 20 carbon atoms of R ^41. Are preferred.

In the formula (41), examples of the aralkyl group having 1 to 20 carbon atoms of L ⁴¹ include a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group and a phenethyl group.

In the formula (41), the polyester structure portion of L ⁴¹ indicates a portion having a polyester structure, and the polyether structure portion indicates a portion having a polyether structure.

  In the formula (41), a is preferably an integer of 1 to 100, and b is preferably an integer of 1 to 1000.

  Specific examples of the polysiloxane compound are not particularly limited. For example, “BYK-300”, “BYK-306”, “BYK-307”, “BYK-310”, and “BYK-315” manufactured by BYK Japan KK , "BYK-322", "BYK-323", "BYK-325", "BYK-330", "BYK-331", "BYK-333", "BYK-337", "BYK-341", "BYK-344", "BYK-345", "BYK-347", "BYK-348", "BYK-349", "BYK-370", "BYK-375", "BYK-377", "BYK" -378 "," BYK-UV3500 "," BYK-UV3510 "," BYK-UV3570 "," BYK-Silican 3700 "," BYK-Silc " “ean3720”; “TSF410”, “TSF411”, “TSF4700”, “TSF4701”, “XF42-B0970”, “TSF4730”, “YF3965”, “TSF4421”, “XF42-334”, “XF42-” manufactured by Momentive. B3629 "," XF42-A3161 "," TSF4440 "," TSF4441 "," TSF4445 "," TSF4450 "," TSF4446 "," TSF4452 "," TSF4460 "and the like. These polysiloxane compounds can be used alone or in combination of two or more.

［式（４２）中、Ｒ^５０は水素原子又はメチル基を表し、Ｌ^４２は炭素数１〜２０のアルキル基、ポリエーテル構造部位、ポリエステル構造部位、又は金属原子を表し、ｃは１以上の整数であり、ｃが２以上の整数である場合、Ｒ^５０及びＬ^４２はそれぞれ同一でも異なっていてもよい］
で表される構成単位を含む重合体又は共重合体が挙げられる。 As the poly (meth) acrylate compound, for example, a compound represented by the formula (42)

[In formula (42), R ⁵⁰ represents a hydrogen atom or a methyl group, L ⁴² represents an alkyl group having 1 to 20 carbon atoms, a polyether structure site, a polyester structure site, or a metal atom, and c is one or more. And when c is an integer of 2 or more, R ⁵⁰ and L ⁴² may be the same or different.
And a polymer or a copolymer containing the structural unit represented by

In the formula (42), examples of the alkyl group having 1 to 20 carbon atoms of L ⁴² include the same as the alkyl group having 1 to 20 carbon atoms of R ^{41 to} R ⁴⁹ in the formula (41).

In the formula (42), the polyester structure portion of L ⁴² indicates a portion having a polyester structure, and the polyether structure portion indicates a portion having a polyether structure.

In the formula (42), as the metal atom of L ^42, for example a sodium atom, a potassium atom and an lithium atom.

  In the formula (42), c is preferably an integer of 1 to 1,000.

  Specific examples of the poly (meth) acrylate compound are not particularly limited. For example, “BYK-350”, “BYK-352”, “BYK-353”, “BYK-354”, and “BYK-354” manufactured by BYK Japan KK BYK-355 "," BYK-358N "," BYK-361N "," BYK-380 "," BYK-381 "," BYK-392 "and the like. These poly (meth) acrylate compounds can be used alone or in combination of two or more.

  When the curable composition (Y) constituting the second hard coat layer contains a surface conditioner, the content of the surface conditioner is preferably 0 with respect to the mass of the solid content of the curable composition (Y). 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, still more preferably 0.1 to 3% by mass. When the content of the surface modifier is within the above range, the bending resistance and the visibility of the optical laminate are easily improved.

  The curable composition (Y) constituting the second hard coat layer may include a photopolymerization initiator. Examples of the photopolymerization initiator include those similar to the photopolymerization initiator exemplified in the section of [First Hard Coat Layer], and the preferable range of the photopolymerization initiator and the content (ratio) thereof are also the same.

  The curable composition (Y) constituting the second hard coat layer may contain other additives other than the polyfunctional (meth) acrylate compound, the surface conditioner, and the photopolymerization initiator. Examples of the other additives include those similar to the other additives exemplified in the section of [First Hard Coat Layer], and the preferable other additives and the ranges of the contents (ratio) thereof are also the same.

  The curable composition (Y) constituting the second hard coat layer may further contain a solvent in order to be applied on the resin film. Examples of the solvent include the same solvents as those exemplified in the section of [First Hard Coat Layer], and the same applies to the range of the content (ratio) of the solvent.

  The curable composition (Y) constituting the second hard coat layer is prepared by, for example, mixing the polyfunctional (meth) acrylate compound, the surface conditioner, the photopolymerization initiator, and the solvent with a conventional method, such as stirring. To obtain a mixture. The order of mixing these is not particularly limited.

  The second hard coat layer is obtained by curing the curable composition (Y). The thickness of the second hard coat layer is preferably 1 to 15 μm, more preferably 2 to 10 μm. When the thickness of the second hard coat layer is in the above range, the bending resistance of the optical laminate is improved, and even when the optical laminate is repeatedly bent, excellent visibility is easily exhibited and the surface hardness is also improved. It's easy to do.

  In one embodiment of the present invention, the ratio of the thickness of the first hard coat layer to the thickness of the second hard coat layer (first hard coat layer: second hard coat layer) is 10: 7 to 7:10. The ratio is preferably 10: 8 to 8:10, more preferably 10: 9 to 9:10, and particularly preferably 10:10. When the ratio of the thickness of the first hard coat layer to the thickness of the second hard coat layer is within the above range, the bending resistance of the optical laminate is easily improved, and even after repeatedly bending the optical laminate. It becomes easy to express excellent visibility.

Although the method for producing the optical laminate of the present invention is not particularly limited, an example of the production method in a preferred embodiment of the present invention will be described below.
The optical laminate of the present invention comprises the following steps:
(A) a step of applying a liquid containing a polyimide resin (sometimes referred to as a polyimide resin varnish) on a substrate to form a coating film;
(B) a step of drying the applied liquid (coating) and then peeling it off from the substrate to form a resin film;
(C) coating the curable composition (X) on at least one surface of the resin film to form a coating film, and then irradiating the coating film with high energy rays to cure the coating film. Forming a first hard coat layer, and (d) applying the curable composition (Y) to the other surface of the substrate to form a coating film, and then applying a high energy ray to the coating film. And irradiating the film to cure the coating film to form a second hard coat layer.

  In the step (a), first, a liquid containing a polyimide resin (polyimide resin varnish) is prepared. For the preparation of the polyimide resin varnish, the diamine compound, the tetracarboxylic acid compound, and, if necessary, the dicarboxylic acid compound, the tricarboxylic acid compound, a tertiary amine acting as an imidation catalyst, and dehydration Other components such as an agent are mixed and reacted to prepare a polyimide resin mixed solution. Examples of the tertiary amine include the aforementioned aromatic amines and aliphatic amines. Examples of the dehydrating agent include acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, isovaleric anhydride and the like. The reaction temperature is not particularly limited, but is, for example, 50 to 350 ° C. Although the reaction time is not particularly limited, it is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be performed under an inert atmosphere or under reduced pressure. In addition, the reaction may be performed in a solvent, and examples of the solvent include a solvent described below used for preparing a polyimide resin varnish. A poor solvent is added to the polyimide resin mixture to precipitate a polyimide resin by a reprecipitation method, which is dried and a precipitate is taken out. If necessary, the precipitate is washed with a solvent such as methanol and dried to obtain a polyimide resin. Next, the polyimide resin is dissolved in a solvent, and if necessary, the inorganic particles, the ultraviolet absorber, the coloring agent, the other additives, and the like are added and stirred to obtain a liquid containing the polyimide resin ( (Polyimide resin varnish) is prepared. In the case where the polyimide resin varnish contains silica particles in the step (a), a silica sol in which the silica particles are dispersed in a solvent (solvent-dispersed silica sol) may be mixed with the resin solution. The solid content concentration of the polyimide resin varnish is preferably 1 to 60% by mass, more preferably 10 to 40% by mass. The solid content concentration (% by mass) indicates the ratio (% by mass) of the solid content to the mass of the resin varnish.

  The solvent used for preparing the polyimide resin varnish is not particularly limited as long as the polyamide resin can be dissolved. Examples of such a solvent include amide solvents such as N, N-dimethylacetamide and N, N-dimethylformamide; lactone solvents such as γ-butyrolactone and γ-valerolactone; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane. Solvent; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof. Among these solvents, amide solvents or lactone solvents are preferred. In addition, the polyimide resin varnish may include water, an alcohol solvent, a ketone solvent, an acyclic ester solvent, an ether solvent, and the like.

  Next, a polyimide resin varnish is applied on a substrate such as a resin substrate, a SUS belt, or a glass substrate by a known application method to form a coating film. 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, dipping, A spray method, a salivation molding method and the like can be mentioned.

  In the step (b), the resin film can be formed by drying and peeling the coating film from the substrate. After the peeling, a drying step of drying the resin film may be further performed. Drying of the coating film can be usually performed at a temperature of 50 to 350 ° C. If necessary, the coating film may be dried under an inert atmosphere or under reduced pressure.

  Examples of the resin substrate include a PET film, a PEN film, a polyimide film, and a polyamideimide film. Among them, from the viewpoint of excellent heat resistance, PET films, PEN films, polyimide films, and other polyamideimide films are preferred.

  In steps (c) and (d), the curable composition dissolved in a solvent may be applied to a resin film. Examples of the solvent include the same solvents as those described in the section of [First Hard Coat Layer], and examples of the coating method include the known coating methods described above.

  The coating film formed on the resin film may be dried. Drying of the coating film can be performed by evaporating the solvent at a temperature of 50 to 150 ° C, and the drying time is usually 30 to 300 seconds. If necessary, the coating film may be dried under an inert atmosphere or under reduced pressure.

In steps (c) and (d), the coating film is irradiated with a high energy ray (for example, active energy ray) to cure the coating film and form a hard coat layer. The irradiation intensity is appropriately determined depending on the composition of the curable composition, and is not particularly limited. However, irradiation in a wavelength region effective for activating the photopolymerization initiator is preferable. The irradiation intensity is preferably 0.1~6,000mW / cm ^2, more preferably 10~1,000mW / cm ^2, more preferably from 20 to 500 mW / cm ^2. When the irradiation intensity is within the above range, an appropriate reaction time can be secured, and yellowing and deterioration of the cured product due to heat radiated from the light source and heat generated during the curing reaction can be suppressed. The irradiation time may be appropriately selected depending on the composition of the curable composition, and is not particularly limited, but the integrated light amount expressed as a product of the irradiation intensity and the irradiation time is preferably 10 to 10,000 mJ /. cm ² , more preferably 50 to 1,000 mJ / cm ² , and still more preferably 80 to 500 mJ / cm ² . When the integrated light amount is within the above range, a sufficient amount of active species derived from the photopolymerization initiator is generated, and the curing reaction can proceed more reliably. Can maintain sex. Further, it is useful that the hardness of the hard coat layer can be further increased by performing the irradiation step in this range.

FIG. 1 shows an example of a layer configuration in the optical laminate of the present invention, but the present invention is not limited to this embodiment. The optical laminate 1 shown in FIG. 1 has a first hard coat layer 4 laminated on one surface of a resin film 2 and a second hard coat layer 3 laminated on the other surface.
The optical laminate 1 of the present invention may include another layer between the resin film 2 and the first hard coat layer 4 and between the resin film 2 and the second hard coat layer 3. As another layer, for example, a functional layer can be mentioned. Examples of the functional layer include layers having various functions such as an ultraviolet absorbing layer, a primer layer, a gas barrier layer, a pressure-sensitive adhesive layer, a hue adjusting layer, and a refractive index adjusting layer described below. The optical laminate of the present invention may include one or more functional layers. Further, one functional layer may have a plurality of functions.

  The ultraviolet absorbing layer is a layer having a function of absorbing ultraviolet light, for example, a main material selected from an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a thermosetting transparent resin, and And a dispersed ultraviolet absorber.

  The hue adjustment layer is a layer having a hue adjustment function, and is a layer that can adjust 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, red iron oxide, titanium oxide-based baked pigment, ultramarine, cobalt aluminate, and carbon black; azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, Organic pigments such as perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, sulene compounds, and diketopyrrolopyrrole compounds; extender pigments such as barium sulfate and calcium carbonate; and basic dyes; Dyes such as acid dyes and mordant dyes can be mentioned.

  The refractive index adjusting layer is a layer having a function of adjusting the refractive index, for example, a layer having a refractive index different from that of the resin film and capable of giving a predetermined refractive index to the optical laminate. The refractive index adjusting layer may be, for example, a resin layer containing an appropriately selected resin and optionally a pigment, or a metal thin film. Examples of the pigment for adjusting the refractive index include silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. The average primary particle size of the pigment may be 0.1 μm or less. When the average primary particle diameter of the pigment is 0.1 μm or less, irregular reflection of light passing through the refractive index adjusting layer can be prevented, and a decrease in transparency can be prevented. Examples of the metal used for the refractive index adjustment layer include metals such as titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and silicon nitride. Oxides or metal nitrides are mentioned.

In one embodiment of the present invention, in the optical laminate of the present invention, the resin film has the number of bending times of more than 100,000 times, or has an indentation hardness of 350 N / mm ² or more measured using a nano indenter. In addition, since the contact angle of oleic acid on the surface of the second hard coat layer is 1 ° or more and less than 65 °, it is excellent in bending resistance and the contact angle of oleic acid on the surface of the first hard coat layer is 65 °. ° or more, the first hard coat layer surface on the viewing side (display section side) is excellent in wiping off stains such as fingerprints. Therefore, even when the optical laminate of the present invention is applied to an image display device such as a flexible display, a change in hue or contrast of a display portion can be effectively suppressed, and excellent visibility can be obtained.

Further, in one embodiment of the present invention, the optical laminate of the present invention has a Charpy impact test, preferably a shock-absorbing energy measured by a flatwise impact test performed on a wide surface of the test piece parallel to the thickness direction of the test piece. In addition to the value being 100 kJ / m ² or more, the contact angle of oleic acid on the surface of the second hard coat layer is 1 ° or more and less than 65 °, so that the bending resistance is excellent and the surface of the first hard coat layer is Since the oleic acid contact angle of the first hard coat layer is 65 ° or more, since the oleic acid contact angle of the first hard coat layer is 65 ° or more, the oleic acid contact angle of the first hard coat layer is 65 ° or more. Excellent in wiping off dirt such as fingerprints on the surface of the hard coat layer. Therefore, even when the optical laminate of the present invention is applied to an image display device such as a flexible display, a change in hue or contrast of a display portion can be effectively suppressed, and excellent visibility can be obtained.

In the above embodiment, the optical laminated body of the present invention has a value of the impact absorption energy of 100 kJ / m ² or more, preferably 110 kJ / m ² or more, more preferably 120 kJ / m ² or more, and further preferably 140 kJ / m ^2. That is all. When the value of the impact absorption energy is equal to or more than the above lower limit, the adhesion between the hard coat layer and the resin film becomes good, and peeling at the time of bending can be prevented. The upper limit value of the impact absorbed energy is not particularly limited, 1,000kJ / ^{m 2} or less, preferably 500 kJ / ^{m 2} or less, more preferably 450 kJ / ^{m 2} or less, more preferably 400 kJ / ^{m 2} or less is there. When it is not more than the above upper limit, the bending resistance of the optical laminate is easily improved. Here, the Charpy impact test is to measure the impact absorption energy of a plastic specified in JIS K 7111-1: 2006 “Plastic-Determination of Charpy impact characteristics-Part 1: Non-instrumented impact test”. Method. In addition, this JIS defines the case where a notched test piece is used and the case where a notched test piece is used. However, since a film is used here, a notched test piece is used.

In the Charpy impact test, the impact absorption energy of a test piece is measured in accordance with JIS K 7111-1: 2006. Specifically, for example, a test piece having a width of about 10 mm and a length of about 120 mm is punched out or cut out from a film having a thickness of 100 μm or less. Next, both ends of the test piece in the longitudinal direction are fixed to a support table so that the test piece does not move due to the impact when punching out with a hammer, and the energy required for breaking the test piece using a Charpy impact tester (ie, the impact absorption energy) ) Is measured. The greater the impact absorption energy, the more difficult it is for the test piece, ie, the film, to break. Specifically, it can be measured by the method described in Examples. An optical laminate having a value of impact absorption energy of 100 kJ / m ² or more can be produced by selecting the resin film, the second hard coat, and the first hard coat described above. In addition, any one of the shock absorption energy measured from the first hard coat layer side and the shock absorption energy measured from the second hard coat layer side may satisfy the above range, and both may be within the above range. It is preferable from the viewpoint of the bending resistance of the optical laminate.

  The optical laminate of the present invention also has excellent surface hardness. The pencil hardness of the optical laminate is preferably HB or higher, more preferably F or higher, and further preferably H or higher. The pencil hardness indicates the pencil hardness of the surface of the first hard coat layer, and can be measured, for example, by the method described in Examples.

  The optical laminate of the present invention has excellent transparency. The yellowness (YI value) of the optical laminate is preferably 5.0 or less, more preferably 3.0 or less, further preferably 2.5 or less, particularly preferably 2.0 or less. When the yellowness of the optical laminate is equal to or less than the above upper limit, the transparency of the optical laminate is improved, and the visibility is improved. The yellowness of the optical laminate can be measured, for example, by the method described in Examples.

  The thickness of the optical laminate of the present invention is preferably 21 to 165 μm, more preferably 27 to 110 μm, and still more preferably 32 to 100 μm. When the thickness of the optical laminate is not less than the lower limit, mechanical strength is easily improved, and when it is not more than the upper limit, generation of cracks due to bending is easily suppressed.

  In the optical laminate of the present invention, the total light transmittance (Tt) is preferably 80% or more, more preferably 85% or more, further preferably 88% or more, still more preferably 89% or more, and particularly preferably 90%. That is all. When the total light transmittance of the optical laminate is equal to or more than the above lower limit, transparency of the optical laminate is improved, and visibility is improved. Further, when the total light transmittance is within the above range, for example, when obtaining the same brightness on the viewing side, it is possible to reduce the illuminance of the backlight as compared with the case where the transmittance is not within the range. , Can contribute to energy saving. The total light transmittance can be measured, for example, by the method described in Examples.

The optical laminate of the present invention can exhibit excellent visibility when used for a front plate (window film) of an image display device. Therefore, the optical laminate of the present invention can be disposed as a front plate on the viewing side surface of an image display device, particularly a flexible display (flexible display device) or a folderable display (foldable display device). The front plate has a function of protecting an image display element in a flexible display or a foldable display.
In one embodiment of the present invention, when the optical laminate is applied to an image display device, the polarizing plate included in the image display device is provided on the surface of the second hard coat layer (the surface opposite to the resin film) via an adhesive. It is preferable to stack them.

  The optical laminate of the present invention has an oleic acid contact angle of 1 ° or more and less than 65 ° on the surface of the second hard coat layer, has excellent adhesion to the pressure-sensitive adhesive, and has a number of bending of the resin film of 100,000. Since the number of times exceeds, the image display device including the optical laminate of the present invention is excellent in bending resistance. Therefore, even in applications where bending is repeatedly performed, for example, when applied to a flexible display, a foldable display, or the like, floating or peeling of the interface between the adhesive and the second hard coat layer or between the resin film and the hard coat layer can be effectively suppressed. In addition, the oleic acid contact angle on the surface of the first hard coat layer is 65 ° or more, and the first hard coat layer is excellent in wiping off stains such as fingerprints on the surface. For this reason, the optical laminate of the present invention can exhibit excellent visibility of the display section of the image display device.

  As the pressure-sensitive adhesive, those containing an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether or the like as a base polymer can be used. Above all, it is preferable to use an adhesive having excellent optical transparency, maintaining appropriate wettability and cohesion, and further having weather resistance and heat resistance, such as an acrylic adhesive.

  The acrylic pressure-sensitive adhesive is obtained by diluting the acrylic pressure-sensitive adhesive composition with a solvent and drying.

The acrylic pressure-sensitive adhesive composition includes an alkyl ester of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, and a butyl group, (meth) acrylic acid, and hydroxyethyl (meth) acrylate. It is preferable to include, as a base polymer, an acrylic polymer obtained by polymerizing a hydroxyl group-containing (meth) acrylate or the like.
The glass transition temperature of the acrylic polymer is preferably 25 ° C. or lower, more preferably 0 ° C. or lower, preferably −60 ° C. or higher, more preferably −40 ° C. or higher.
The weight average molecular weight of the acrylic polymer is preferably 100,000 or more, more preferably 1,000,000 or more, and preferably 2,500,000 or less in terms of standard polystyrene.

  The acrylic pressure-sensitive adhesive composition can include an isocyanate compound such as trimethylolpropane-modified tolylene diisocyanate as a crosslinking agent, and also include a silane compound such as 3-glycidoxypropyltrimethoxysilane as a silane coupling agent. be able to. The content of the crosslinking agent is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer, and the content of the silane coupling agent is preferably 100 parts by mass with respect to the acrylic polymer. Preferably it is 0.1-5 mass parts.

  The acrylic pressure-sensitive adhesive composition is obtained by mixing the acrylic polymer and, if necessary, additives such as the crosslinking agent, the silane coupling agent, and the antistatic agent by stirring or the like.

The acrylic pressure-sensitive adhesive layer is prepared by dissolving or dispersing the acrylic pressure-sensitive adhesive composition in a solvent such as toluene or ethyl acetate to prepare a 10 to 40% by mass solution, and applying the solution to the surface of the second hard coat layer of the optical laminate. May be directly applied and dried to form, or in advance, an acrylic pressure-sensitive adhesive composition is coated on a base material such as a separator, and then dried to form an acrylic pressure-sensitive adhesive layer with a separator. Then, the separator may be peeled off and bonded to the surface of the second hard coat layer of the optical laminate. The thickness of the pressure-sensitive adhesive layer is determined according to its adhesive strength and the like, but is suitably about 1 to 25 μm.
In this specification, the pressure-sensitive adhesive layer may be simply referred to as a pressure-sensitive adhesive.

[Flexible display device]
In the present invention, a flexible image display device includes the optical laminate of the present invention. The optical laminate of the present invention is preferably used as a front plate in a flexible image display device, and the front plate may be referred to as a window film. The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel. The laminate for a flexible image display device is arranged on the viewing side with respect to the organic EL display panel, and is configured to be bendable. ing. The laminate for a flexible image display device may further contain a polarizing plate, preferably a circularly polarizing plate, and a touch sensor, and the order of lamination thereof is arbitrary. Alternatively, it is preferable that the window film, the touch sensor, and the polarizing plate are laminated in this order. The presence of the polarizing plate on the viewing side relative to the touch sensor is preferable because the pattern of the touch sensor is hardly viewed and the visibility of the display image is improved. Each member can be laminated using an adhesive, a pressure-sensitive adhesive or the like. In addition, a light-shielding pattern formed on at least one surface of any one of the window film, the polarizing plate, and the touch sensor can be provided.

(Circular polarizing plate)
As described above, the flexible display device preferably includes a polarizing plate, particularly a circular polarizing plate. The circularly polarizing plate is a functional layer having a function of transmitting only right or left circularly polarized light components by laminating a λ / 4 retardation plate on a linearly polarizing plate. For example, by converting external light into right-handed circularly polarized light, the external light reflected by the organic EL panel and turned into left-handed circularly polarized light is blocked, and only the light-emitting components of the organic EL are transmitted to suppress the influence of the reflected light, thereby forming an image. Used to make it easier to see. 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 ° in theory, but practically 45 ± 10 °. The linear polarizing plate and the λ / 4 retardation plate do not necessarily have to be stacked adjacently, as long as the relationship between the absorption axis and the slow axis satisfies the above range. It is preferable to achieve perfect circularly polarized light at all wavelengths, but this is not always necessary in practical use. Therefore, the circularly polarizing plate in the present invention includes an elliptically polarizing plate. It is also preferable that a λ / 4 retardation film is further laminated on the viewing side of the linear polarizing plate to make the outgoing light circularly polarized so as to improve the visibility in a state where polarized sunglasses are worn.

The linear polarizing plate is a functional layer having a function of transmitting light vibrating in the transmission axis direction, but blocking polarization of a vibration component perpendicular to the light. The linear polarizing plate may include 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 linearly polarizing plate is in the above range, the flexibility of the linearly polarizing plate tends to hardly decrease.
The linear polarizer may be a film-type polarizer manufactured by dyeing and stretching a polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) -based film. A dichroic dye such as iodine is adsorbed on a PVA-based film oriented by stretching or stretched in a state of being adsorbed on PVA, whereby the dichroic dye is oriented and exhibits polarizing 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 included. The stretching and dyeing steps may be performed on 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 used is preferably 10 to 100 μm, and the stretching ratio is preferably 2 to 10 times.
Further, another example of the polarizer includes a liquid crystal application type polarizer formed by applying a liquid crystal polarizing composition. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The liquid crystalline compound only needs to have a property of exhibiting a liquid crystal state, and particularly preferably has a higher order alignment state such as a smectic phase because high polarization performance can be exhibited. Further, the liquid crystal compound preferably has a polymerizable functional group.
The dichroic dye compound is a dye that is aligned with the liquid crystal compound and exhibits dichroism, and may have a polymerizable functional group, and the dichroic dye itself has liquid crystallinity. It may be.
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 manufactured by applying a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer. The liquid crystal polarizing layer can be formed thinner than the film type polarizer, and the thickness is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.
The alignment film is manufactured, for example, by applying an alignment film forming composition on a substrate and imparting the alignment by rubbing, polarized light irradiation, or the like. The composition for forming an alignment film includes an alignment agent, and may further include a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like. Examples of the aligning agent include polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides. In the case of using an aligning agent that imparts an orientation by polarized light irradiation, it is preferable to use an aligning agent containing a cinnamate group. The weight average molecular weight of the polymer used as the alignment 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 that the alignment regulating force is sufficiently exhibited.
The liquid crystal polarizing layer can be peeled off from the substrate and transferred to be laminated, or the substrate can be laminated as it is. It is also preferable that the base material plays a role as a transparent base material for a protective film, a retardation plate, or a window film.
The protective film may be any transparent polymer film, and the same materials and additives as those used for the transparent substrate of the window film can be used. Further, a coating type protective film obtained by applying and curing a cationically curable composition such as an epoxy resin or a radically curable composition such as an acrylate may be used. The protective film may be, if necessary, a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or a dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, and an antioxidant. , A lubricant, a solvent, and the like. 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, the flexibility of the film tends to hardly decrease.

The λ / 4 retardation plate is a film that gives a λ / 4 phase difference in a direction (in-plane direction of the film) perpendicular to the traveling direction of the incident light. 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, and a polycarbonate film. The λ / 4 retardation plate may include a retardation adjuster, a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or a dye, a fluorescent brightener, a dispersant, a heat stabilizer, and a light stabilizer, if necessary. Agents, antistatic agents, antioxidants, lubricants, solvents and the like.
The thickness of the stretch type retardation plate is preferably 200 μm or less, more preferably 1 to 100 μm. When the thickness of the stretched retardation film is in the above range, the flexibility of the stretched retardation film tends to be hardly reduced.
Another example of the λ / 4 retardation plate is a liquid crystal-coated retardation plate formed by applying a liquid crystal composition.
The liquid crystal composition contains a liquid crystal compound exhibiting a liquid crystal state such as nematic, cholesteric, or 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 applying and curing a liquid crystal composition on a base to form a liquid crystal retardation layer, similarly to the liquid crystal polarizing layer. The liquid crystal application type retardation plate can be formed to be thinner than the stretch type 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-coated retardation plate can be peeled off from a substrate and transferred and laminated, or the substrate can be laminated as it is. It is also preferable that the base material plays a role as a transparent base material for a protective film, a retardation plate, or a window film.
In general, there are many materials exhibiting a large birefringence at a short wavelength and a small birefringence at a long wavelength. 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 λ / 4 near 560 nm where the visibility is high. It is designed to be 180 nm, more preferably 130 to 150 nm. An inverse dispersion λ / 4 retardation plate using a material having a wavelength dispersion characteristic of birefringence opposite to that of a normal one is preferable in that visibility becomes good. As such a material, for example, a stretch type retarder described in JP-A-2007-232873 and a liquid crystal-coated phase retarder described in JP-A-2010-30979 can be used. .
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 Patent Application Laid-Open No. H10-90521). The λ / 2 retardation plate is also manufactured by the same material method as the λ / 4 retardation plate. The combination of the stretching type retardation plate and the liquid crystal coating type retardation plate is optional, but both can be reduced in thickness by using the liquid crystal coating type retardation plate.
There is known a method of laminating a positive C plate on the circularly polarizing plate in order to enhance visibility in an oblique direction (for example, Japanese Patent Application Laid-Open 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 from -200 to -20 nm, more preferably from -140 to -40 nm.

[Touch sensor]
As described above, the flexible display device preferably includes the touch sensor. The touch sensor is used as an input unit. Examples of the touch sensor include various types such as a resistance film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitance type, and preferably a capacitance type.
The capacitive touch sensor is divided into an active area and a non-active area located outside the active area. The active area is an area corresponding to an area (display unit) where a screen is displayed on the display panel, and is an area where a user's touch is sensed. Display area). The touch sensor is formed on a substrate having a flexible characteristic, a sensing pattern formed on an active region of the substrate, and an inactive region of the substrate, and is connected to an external driving circuit through the sensing pattern and a pad unit. For each sensing line. The same material as the transparent substrate of the window film can be used as the substrate having flexible characteristics.

  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 directions different from each other. The first pattern and the second pattern are formed on the same layer, and the respective patterns must be electrically connected in order to detect a touched point. The first pattern is a form in which a plurality of unit patterns are connected to each other via a joint, while the second pattern has a structure in which a plurality of unit patterns are separated from each other in an island form. A separate bridge electrode is required to make the connection. A well-known transparent electrode can be applied to the electrode for the connection of the second pattern. As the material of the transparent electrode, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO) , Cadmium tin oxide (CTO), PEDOT (poly (3,4-ethylenedioxythiophene)), carbon nanotube (CNT), graphene, metal wire, and the like, and preferably ITO. 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, terenium, and chromium. These may be used alone or in combination of two or more. Can be.

The bridge electrode may be formed on the insulating layer above the sensing pattern with an insulating layer interposed therebetween. The bridge electrode may be formed on the substrate, and the insulating layer and the 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 these. it can.
Since the first and second patterns 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 can connect the second pattern via a contact hole formed in the insulating layer.

The touch sensor is induced by a difference in transmittance between a pattern region where a sensing pattern is formed and a non-pattern region where a sensing pattern is not formed, specifically, a difference in refractive index in these regions. As a means for appropriately compensating for the difference in light transmittance, an optical adjustment 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 can be formed by coating a photocurable composition containing 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 includes, for example, a copolymer of each monomer such as an acrylate-based monomer, a styrene-based monomer, and a carboxylic acid-based monomer as long as the effects of the present invention are not impaired. be able to. 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 include 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 a flexible image display device and a film member (linear polarizing plate, λ / 4 retardation plate, etc.) forming each layer are bonded by an adhesive. Can be. Examples of the adhesive include a water-based adhesive, an organic solvent-based adhesive, a solvent-free adhesive, a solid adhesive, a solvent volatile adhesive, a moisture-curable adhesive, a heat-curable adhesive, an anaerobic-curable adhesive, and an active energy ray-curable adhesive. Commonly used adhesives such as a mold adhesive, a curing agent-mixed adhesive, a hot-melt adhesive, a pressure-sensitive adhesive (adhesive), a re-wet adhesive, and the like can be used, and preferably an aqueous solvent is volatilized. 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 strength and the like, and is preferably 0.01 to 500 μm, and more preferably 0.1 to 300 μm. A plurality of adhesive layers are present in the laminate for a flexible image display device, and the thickness and type of each may be the same or different.

  As the water-based water-based solvent-evaporating adhesive, a water-soluble polymer such as a polyvinyl alcohol-based polymer, a starch, an ethylene-vinyl acetate-based emulsion, or a styrene-butadiene-based emulsion can be used as a main polymer. . 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. When bonding with the aqueous water-based solvent-evaporating adhesive, after injecting the aqueous water-based solvent-evaporable adhesive between the layers to be bonded and laminating the adhesion layer, it is possible to impart adhesiveness by drying. . When the water-based water-based solvent-evaporating adhesive is used, the thickness of the adhesive layer is preferably 0.01 to 10 μm, more preferably 0.1 to 1 μm. When the water-based water-based solvent-evaporating adhesive is used for a plurality of layers, the thickness and type of each layer may be the same or different.

The active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material that forms an adhesive layer upon irradiation with an active energy ray. The active energy ray-curable composition may contain at least one polymer of the same radical polymerizable compound and cationic polymerizable compound as those contained in the hard coat composition. As the radical polymerizable compound, the same compound as the radical polymerizable compound in the hard coat composition can be used.
As the cationic polymerizable compound, the same compound as the cationic polymerizable compound in the hard coat composition can be used.
Epoxy compounds are particularly preferred as the cationically polymerizable compound used in the active energy ray-curable composition. It is also preferable to include a monofunctional compound as a reactive diluent in order to reduce the viscosity of the adhesive composition.
The active energy ray composition may include a monofunctional compound in order to reduce the viscosity. Examples of the monofunctional compound include an acrylate monomer having one (meth) acryloyl group in one molecule and a compound having one epoxy group or oxetanyl group in one molecule, for example, glycidyl (meth) A) acrylate and the like.
The active energy ray composition can further include a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, and these are appropriately selected and used. These polymerization initiators are decomposed by at least one of irradiation with active energy rays and heating to generate radicals or cations, thereby promoting radical polymerization and cationic polymerization. In the description of the hard coat composition, an initiator capable of initiating at least one of radical polymerization and cationic polymerization by irradiation with active energy rays can be used.
The active energy ray-curable composition further comprises an ion scavenger, an antioxidant, a chain transfer agent, an adhesion promoter, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, a defoamer solvent, an additive, and a solvent. Can be included. When the two adhesive layers are bonded by the active energy ray-curable adhesive, the active energy ray-curable composition is applied to one or both of the adhesive layers, and then bonded, and any one of the adhesive layers is bonded. Alternatively, both the layers to be bonded can be bonded by irradiating them with an active energy ray and curing them. When the active energy ray-curable adhesive is used, 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.
The same adhesive as described above can be used as the adhesive. When using a plurality of layers of the pressure-sensitive adhesive, the thickness of each layer may be the same or different.

[Shading pattern]
The light shielding pattern can be applied as at least a part of a bezel or a housing of the flexible image display device. The visibility of the image is improved by concealing the wiring arranged on the peripheral portion of the flexible image display device by the light-shielding pattern so as to make the wiring less visible. The light-shielding pattern may be in the form of a single layer or multiple layers. The color of the light-shielding pattern is not particularly limited, and may be various colors such as black, white, and metal. The light-shielding pattern can be formed of a pigment for realizing a color and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or silicone. These can be used alone or in a mixture of two or more. The light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light-shielding pattern is preferably 1 to 100 μm, more preferably 2 to 50 μm. It is also preferable to provide a shape such as inclination in the thickness direction of the light-shielding pattern.

  Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

1. Measurement and Evaluation (1) Measurement of Thickness The thickness of the resin film in the examples and comparative examples was measured using a Micrometer (Mitutoyo), and the thickness of the first hard coat layer and the second hard coat layer was measured by Filmmetrics. The film thickness was measured using an F20 desktop film thickness system.

(2) Measurement of flex resistance The number of flexes of the resin films in Examples and Comparative Examples was determined as follows in accordance with ASTM D2176-16. The resin film was cut into a strip of 15 mm × 100 mm using a dumbbell cutter. The cut resin film is set on an MIT bending fatigue tester (“Model 0530”, manufactured by Toyo Seiki Seisaku-sho, Ltd.), and the test speed is 175 cpm, the bending angle is 135 °, the load is 0.75 kgf, and the bending radius of the bending clamp is set. Under the condition of R = 3 mm, the number of reciprocating bendings in the front-back direction until the resin film was broken was measured, and this was defined as the number of bendings.

(3) Measurement of Indentation Hardness The indentation hardness of the cross section in the thickness direction of the resin films of Examples and Comparative Examples was measured using a nanoindentation tester (ENT-2100, manufactured by Elionix Inc.) under the following conditions. The measurement was carried out. The measurement position was the center of the resin film plane, and the average value of the five points close to the center in the thickness direction of the center was defined as the indentation hardness (N / mm ² ).
Indenter: Birkovich indenter Surface detection: load (0.6mgf)
Load curve: 0.6 mN over 10 seconds (linear)
Creep: 0.6mN for 10 seconds
Unloading curve: 0 mN over 10 seconds (linear)

(4) Measurement of oleic acid contact angle According to JIS R3257, the oleic acid contact angle was measured using a contact angle meter (“CA-X”, manufactured by Kyowa Interface Chemical Co., Ltd.).

(5) Charpy impact test In accordance with JIS K 7111-1: 2006, the impact absorption energy of the optical laminates of Examples and Comparative Examples was determined. From the optical laminates of the examples and the comparative examples, rectangular test pieces having a width of 10 mm and a length of 120 mm were cut out. The test piece is fixed to the support at both ends in the long side direction so that the test piece does not move due to the impact when punching out with a hammer, and the cutting edge of the hammer is moved by a Charpy impact tester manufactured by Yasuda Seiki Seisakusho Co., Ltd. The test piece was struck against the first hard coat layer side of the optical laminate so as to be parallel to the thickness direction at the central portion in the major axis direction, and the energy required for breaking the film (that is, impact absorption energy) was measured. In addition, it replaced with the hammer hitting side and performed also on the 2nd hard-coat layer side instead of the 1st hard-coat layer side.

(6) Visibility evaluation (production of visibility evaluation sample)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube, 97.0 parts by mass of n-butyl acrylate, 1.0 part by mass of acrylic acid, and 0.5 parts of 2-hydroxyethyl acrylate were added. Parts by mass, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2′-azobisisobutyronitrile were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was heated to 60 ° C. with stirring under a nitrogen atmosphere, reacted for 6 hours, and then cooled to room temperature. When the weight-average molecular weight of a part of the obtained solution was measured, it was confirmed that 1.8 million (meth) acrylate polymers were formed.
100 parts by mass of the obtained (meth) acrylic ester polymer (in terms of solid content; the same applies hereinafter) and trimethylolpropane-modified tolylene diisocyanate (trade name “Coronate L” manufactured by Tosoh Corporation) as an isocyanate-based crosslinking agent )) And 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (trade name “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, and To give a pressure-sensitive adhesive composition. Next, the adhesive composition was diluted with ethyl acetate to obtain a coating solution of the adhesive composition.
After applying the coating solution to a release-treated surface (release layer surface) of a separator (manufactured by Lintec Corporation: SP-PLR382190) by an applicator so that the thickness after drying is 25 μm, the coating solution is applied at 100 ° C. After drying for 1 minute, an adhesive layer was obtained. Then, another separator (manufactured by Lintec Corporation: SP-PLR381031) was attached to the surface of the adhesive layer opposite to the surface to which the separator was attached, to obtain an adhesive layer with a double-sided separator. .
After separating the separator from the pressure-sensitive adhesive layer with a double-sided separator, the pressure-sensitive adhesive layer is bonded to the surface of the second hard coat layer of the optical laminate, and the pressure-sensitive adhesive layer has a surface opposite to the side on which the optical laminate is bonded. A PET film (manufactured by Toyobo Co., Ltd., trade name: Cosmoshine (registered trademark) A4100) was bonded to the surface to obtain a laminate having an optical laminate / adhesive / PET film in this order.

(Visibility evaluation)
A laminate (visibility measurement sample) having an optical laminate / adhesive / PET film in that order was cut into a strip of 15 mm × 100 mm using a dumbbell cutter. The cut laminate is set on a MIT folding fatigue tester (“Model 0530”, manufactured by Toyo Seiki Seisaku-sho, Ltd.), and the test speed is 175 cpm, the bending angle is 135 °, the load is 0.75 kgf, and the bending clamp is bent. Under the condition of a radius R = 3 mm, bending was performed 1000 times in the reciprocating bending direction (bending number) in the front and back directions. Three testers touched the surface of the first hard coat layer of the folded optical laminate with a finger ten times each to give a fingerprint, and wiped the fingerprint four times with a bencot. Thereafter, the state of appearance change such as discoloration and whitening due to fingerprint residue and peeling of the adhesive was confirmed from the surface side of the first hard coat layer under a fluorescent lamp, and visibility was determined based on the following criteria.
(Evaluation criteria)
A: No fingerprint remaining and no change in appearance such as discoloration or whitening are observed.
B: Fingerprint remains and slight changes in appearance such as discoloration and whitening are observed.
C: Fingerprint remaining and changes in appearance such as discoloration and whitening are clearly recognized.

(7) Measurement of Pencil Hardness Based on JIS K5600-5-4: 1999, the pencil hardness of the surface of the first hard coat layer of the optical laminate obtained in each of Examples and Comparative Examples was measured by Mitsubishi Pencil Co., Ltd. Was measured using a Uni. More specifically, the optical laminate was fixed on a glass plate having a thickness of 2 mm, and the measurement was performed under the conditions of an angle of 90 °, a load of 750 g, and a scanning speed of 60 mm / min. The presence or absence of scratches was evaluated, and the pencil hardness was determined.

(8) Measurement of Yellowness (YI Value) Using a spectrophotometer (U-4100) manufactured by Hitachi, Ltd., a tristimulus value X calculated by a calculation method specified in JIS Z 8701: 1982. , Y, and Z, and the following formula, the yellowness (YI value) of the optical laminates obtained in Examples and Comparative Examples was calculated.
YI = 100 (1.28X-1.06Z) / Y

(9) Measurement of Total Light Transmittance (Tt) The total light transmittance Tt of the optical laminates obtained in Examples and Comparative Examples was measured by Suga Test Instruments Co., Ltd. in accordance with JIS K 7105: 1981. It was measured by a fully automatic haze computer HGM-2DP.

(10) Measurement of Weight Average Molecular Weight (Mw) The weight average molecular weights (Mw) of the polyimides and polyamideimides of Examples and Comparative Examples were determined by gel permeation chromatography (GPC) measurement in terms of standard polystyrene. Specific measurement conditions are as follows.
(I) Pretreatment method To the polyimides of Examples and Comparative Examples, a DMF eluent (10 mM lithium bromide solution) was added to a concentration of 2 mg / mL, heated at 80 ° C. for 30 minutes with stirring, cooled, The solution obtained by filtration with a 0.45 μm membrane filter was used as a measurement solution.
(ii) Measurement condition column: TSKgel SuperAWM-H × 2 + SuperAW2500 × 1 (6.0 mm ID × 150 mm × 3)
Eluent: DMF (10 mM lithium bromide added)
Flow rate: 1.0 mL / min.
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μL
Molecular weight standard: Standard polystyrene

2. Production of resin film (1) Resin film A
Polyimide (“KPI-MX300F (100)” manufactured by Kawamura Sangyo Co., Ltd., fluorine atom-containing polyimide, weight average molecular weight 300,000) is dissolved in γ-butyrolactone to obtain a polyimide solution having a polyimide concentration of 12% by mass. Was. The obtained polyimide solution was applied to a glass substrate and heated at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes to remove the solvent. Thereafter, the polyimide film was peeled off from the glass substrate, a metal frame was attached, and heating was performed at 200 ° C. for 30 minutes to obtain a transparent resin film having a thickness of 80 μm.

(2) Resin film B
Polyimide ("KPI-MX300F (100)" manufactured by Kawamura Sangyo Co., Ltd., fluorine atom-containing polyimide, weight average molecular weight 300,000) is dissolved in γ-butyrolactone to prepare a polyimide solution having a polyimide concentration of 16% by mass. Then, a solution in which silica particles (average primary particle diameter: 22 nm) having a solid content of 30% by mass were dispersed in γ-butyrolactone was mixed with the polyimide solution, and the mixture was stirred for 30 minutes. The mass ratio of silica particles to polyimide was 40:60. A polyimide solution containing silica particles was applied to a glass substrate and heated at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes to remove the solvent. Thereafter, the polyimide film was peeled off from the glass substrate, a metal frame was attached, and heating was performed at 200 ° C. for 30 minutes to obtain a transparent resin film having a thickness of 50 μm.

(3) Resin film C
Under a nitrogen gas atmosphere, 40 g (124.91 mmol) of TFMB and 682.51 g of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc with stirring at room temperature. Next, 16.78 g (37.77 mmol) of 6FDA was added to the flask, and the mixture was stirred at room temperature for 3 hours. Thereafter, 3.72 g (12.59 mmol) of OBBC and 15.34 g (75.55 mmol) of TPC were added to the flask, and the mixture was stirred at room temperature for 1 hour. Next, 8.21 g (88.14 mmol) of 4-methylpyridine and 15.43 g (151.10 mmol) of acetic anhydride were added to the flask, and the mixture was stirred at room temperature for 30 minutes, and then heated to 70 ° C. using an oil bath. The mixture was further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in the form of a thread, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C. to obtain a polyamideimide. The weight average molecular weight (Mw) of the polyamideimide was 400,000.
A BET diameter (average particle diameter measured by the BET method) is 27 nm, and methanol-dispersed surface-modified silica sol (silica sol in which silica particles whose surface is modified with an organic group is dispersed in methanol) is replaced with γ-butyrolactone (GBL); GBL-dispersed organically treated silica sol (solid content concentration 30%) was obtained. For the replacement of the solvent, γ-butyrolactone (GBL) was added to a methanol-dispersed surface-modified silica sol, and methanol was evaporated under a hot water bath at 45 ° C. with a vacuum evaporator at 400 hPa for 1 hour and at 250 hPa for 1 hour. It carried out by heating up to 70 degreeC and heating for 30 minutes.
At room temperature, the obtained polyamideimide and GBL-dispersed organically treated silica sol were mixed in a GBL solvent so that the composition ratio of the resin and the silica particles was 60:40, and Sumisorb 340 (Sumitika Chemtex Co., Ltd.) was added thereto. And Sumiplast Violet B (manufactured by Sumika Chemtex Co., Ltd.) were added at 5.7% by mass and 35 ppm, respectively, based on the total mass of the polyamideimide and silica particles, and the mixture was stirred until uniform. A polyamide imide varnish having a solid content of 10% by mass was obtained.
The obtained polyamideimide varnish was filtered through a filter having a mesh size of 10 μm, and then applied to a smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name “A4100”) so that the thickness of the self-standing film was 55 μm. After drying at 50 ° C. for 30 minutes and then at 140 ° C. for 15 minutes, the resulting coating film was peeled from the polyester substrate to obtain a self-supporting film. The self-standing film was fixed on a metal frame, and dried at 200 ° C. for 40 minutes in the atmosphere to obtain a transparent resin film having a thickness of 50 μm.

(4) Resin film D
Under a nitrogen gas atmosphere, 53.05 g (165.66 mmol) of TFMB and 670.91 g of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 22.11 g (49.77 mmol) of 6FDA and 4.88 g (16.59 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) were added to the flask, and then TPC20. .21 g (99.54 mmol) were added and stirred at room temperature for 1 hour. Next, 10.53 g (133.08 mmol) of pyridine and 13.77 g (134.83 mmol) of acetic anhydride were added to the flask, and the mixture was stirred at room temperature for 30 minutes, heated to 70 ° C. using an oil bath, and further heated for 3 hours. The mixture was stirred to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in the form of a thread, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C. to obtain a polyamideimide. The weight average molecular weight (Mw) of the polyamideimide was 190,000.
Resin film C except that the composition ratio of the resin and the silica particles is 70:30, and that Sumisorb 340 (manufactured by Sumika Chemtex) and Sumiplast Violet B (manufactured by Sumika Chemtex) are not added. A polyamideimide varnish having a solid content of 10% by mass was obtained in the same manner as in the above, to obtain a transparent resin film having a thickness of 50 μm.

(5) Resin film E
Under a nitrogen gas atmosphere, 53.05 g (165.66 mmol) of TFMB and 669.70 g of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 24.56 g (55.30 mmol) of 6FDA and then 22.46 g (110.61 mmol) of TPC were added to the flask, and the mixture was stirred at room temperature for 1 hour. Next, 10.51 g (132.84 mmol) of pyridine and 13.74 g (134.59 mmol) of acetic anhydride were added to the flask, and the mixture was stirred at room temperature for 30 minutes, heated to 70 ° C. using an oil bath, and further heated for 1 hour. The mixture was stirred to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in the form of a thread, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C. to obtain a polyamideimide. The weight average molecular weight (Mw) of the polyamideimide was 197,000.
A transparent resin film having a thickness of 50 μm was obtained in the same manner as the resin film D except that the composition ratio of the resin and the silica particles was set to 95: 5. Got.

3. Production of curable composition (1) Curable composition A
As a curable compound, 30.9 parts by mass of pentaerythritol tetraacrylate and 30.9 parts by mass of trimethylolpropane triacrylate, and as a fluorine-containing compound, a polymer type fluorine-containing surfactant ("BYK-340" manufactured by BYK Japan KK) )), 0.6 parts by mass of a fluorine-based water and oil repellent (Neos Co., Ltd., "Futadient (registered trademark) 601ADH2"), 1.9 parts by mass as a photopolymerization initiator (BASF Japan Ltd. ), "IRGACURE (registered trademark) 184", 1-hydroxycyclohexylphenyl ketone), and 35.5 parts by mass of propylene glycol monomethyl ether as a solvent, to prepare a curable composition A.

(2) Curable composition B
32.7 parts by mass of pentaerythritol tetraacrylate and 32.7 parts by mass of trimethylolpropane triacrylate as a curable compound, and a polysiloxane compound ("BYK-307", manufactured by BYK Japan KK, polyether modified) as a surface conditioner Dimethylsiloxane), 2.0 parts by mass ("IRGACURE 184", manufactured by BASF Japan K.K.) as a photopolymerization initiator, and 32.7 parts by mass of propylene glycol monomethyl ether as a solvent, and the curable composition B was mixed. Was prepared.

(3) Curable composition C
32.5 parts by mass of pentaerythritol tetraacrylate and 32.5 parts by mass of trimethylolpropane triacrylate as a curable compound, and a poly (meth) acrylate compound ("BYK-350" manufactured by BYK Japan KK) as a surface conditioner (Acrylic copolymer), 1.9 parts by mass of photopolymerization initiator (“IRGACURE 184”, manufactured by BASF Japan Ltd.) and 32.5 parts by mass of propylene glycol monomethyl ether (PGM) as a solvent. And curable composition C were prepared.

  Table 1 shows the compositions of the curable compositions A to C.

4. Production of optical laminate (Example 1 (Reference Example) )
Using a resin film A having a thickness of 80 μm, the curable composition A is applied on one surface thereof by a bar coater, and dried at 80 ° C. for 3 minutes. Then, under a nitrogen atmosphere, using a high-pressure mercury lamp, 500 mJ / cm ² , The first hard coat layer (HC1) was formed by irradiating and curing under the condition of 200 mW / cm ² . The curable composition C is applied to the other surface of the resin film A by a bar coater, dried at 80 ° C. for 3 minutes, and then, under a nitrogen atmosphere, using a high-pressure mercury lamp under the conditions of 500 mJ / cm ² and 200 mW / cm ² . And hardened to form a second hard coat layer to obtain an optical laminate. The thickness of each of the first hard coat layer and the second hard coat layer (HC2) was 3 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 10 °. The pencil hardness of the optical laminate was H.

(Example 2 (Reference Example) )
Using a resin film A having a thickness of 80 μm, the curable composition A is applied on one surface thereof by a bar coater, and dried at 80 ° C. for 3 minutes. Then, under a nitrogen atmosphere, using a high-pressure mercury lamp, 500 mJ / cm ² The first hard coat layer was formed by irradiating and curing under the condition of 200 mW / cm ² . The curable composition B was applied to the other surface of the resin film A with a bar coater, dried at 80 ° C. for 3 minutes, and then under a nitrogen atmosphere using a high-pressure mercury lamp under conditions of 500 mJ / cm ² and 200 mW / cm ² . And hardening to form a second hard coat layer to obtain an optical laminate. The thickness of each of the first hard coat layer and the second hard coat layer was 8 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 46 °. The pencil hardness of the optical laminate was 3H.

(Example 3 (Reference Example) )
A resin film B having a thickness of 50 [mu] m, the curable composition A on one surface thereof was coated by a bar coater, and after 3 minutes drying at 80 ° C., under a nitrogen atmosphere, using a high-pressure mercury lamp, 500 mJ / cm ^2, The first hard coat layer was formed by irradiating and curing under the condition of 200 mW / cm ² . The curable composition C is applied to the other surface of the resin film A by a bar coater, dried at 80 ° C. for 3 minutes, and then, under a nitrogen atmosphere, using a high-pressure mercury lamp under the conditions of 500 mJ / cm ² and 200 mW / cm ² . And hardened to form a second hard coat layer to obtain an optical laminate. The thickness of each of the first hard coat layer and the second hard coat layer was 8 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 10 °. The pencil hardness of the optical laminate was 3H.

(Example 4)
An optical laminate was obtained in the same manner as in Example 1, except that the resin film C having a thickness of 50 μm was used. The thickness of each of the first hard coat layer and the second hard coat layer was 3 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 10 °. The pencil hardness of the optical laminate was H.
(Example 5)
An optical laminate was obtained in the same manner as in Example 3, except that the resin film C having a thickness of 50 μm was used. The thickness of each of the first hard coat layer and the second hard coat layer was 8 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 10 °. The pencil hardness of the optical laminate was 3H.
(Example 6)
An optical laminate is obtained in the same manner as in Example 4, except that the resin film D having a thickness of 50 μm is used. The thickness of each of the first hard coat layer and the second hard coat layer is 3 μm. The contact angle of oleic acid on the surface of the first hard coat layer is 76 °, and the contact angle of oleic acid on the surface of the second hard coat layer is 10 °.
(Example 7)
An optical laminate is obtained in the same manner as in Example 4, except that the resin film E having a thickness of 50 μm is used. The thickness of each of the first hard coat layer and the second hard coat layer is 3 μm. The contact angle of oleic acid on the surface of the first hard coat layer is 76 °, and the contact angle of oleic acid on the surface of the second hard coat layer is 10 °.

(Comparative Example 1)
Using a resin film A having a thickness of 80 μm, the curable composition A is applied on one surface thereof by a bar coater, and dried at 80 ° C. for 3 minutes. Then, under a nitrogen atmosphere, using a high-pressure mercury lamp, 500 mJ / cm ² The first hard coat layer was formed by irradiating and curing under the condition of 200 mW / cm ² . The curable composition A was applied to the other surface of the resin film A with a bar coater, dried at 80 ° C. for 3 minutes, and then, under a nitrogen atmosphere, using a high-pressure mercury lamp under conditions of 500 mJ / cm ² and 200 mW / cm ² . And hardening to form a second hard coat layer to obtain an optical laminate.
The thickness of each of the first hard coat layer and the second hard coat layer was 3 μm. The oleic acid contact angle on the surface of the first hard coat layer was 76 °, and the oleic acid contact angle on the surface of the second hard coat layer was 76 °. The pencil hardness of the optical laminate was H.

(Comparative Example 2)
An optical laminate was obtained in the same manner as in Comparative Example 1, except that the curable composition C was used instead of the curable composition A. The thickness of each of the first hard coat layer and the second hard coat layer was 3 μm. The contact angle of oleic acid on the surface of the first hard coat layer was 10 °, and the contact angle of oleic acid on the surface of the second hard coat layer was 10 °. The pencil hardness of the optical laminate was H.

  In the optical laminates obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the thickness of each layer (first hard coat layer / resin film / second hard coat layer); the number of bendings and the indentation hardness of the resin film Table 2 shows the contact angle of each hard coat layer; and the results of impact absorption energy, yellowness (YI value), total light transmittance (Tt), and visibility evaluation of the optical laminate.

In all of the optical laminates obtained in Examples 1 to 5, the result of the visibility evaluation was A or B. That is, the optical laminates obtained in Examples 1 to 5 have excellent fingerprint wiping properties and bending resistance even after the MIT bending fatigue test, that is, even after repeating bending 1,000 times, Excellent visibility can be exhibited. In contrast, Comparative Example 1 in which the oleic acid contact angle on the surface of the second hard coat layer is out of the range of 10 ° or more and less than 65 °, and the oleic acid contact angle on the surface of the first hard coat layer is less than 65 °. All of the optical laminates obtained in Comparative Example 2 had a visibility evaluation result of C, indicating poor visibility.
Also regarding the optical laminates obtained in Examples 6 and 7, the result of the visibility evaluation is A or B, and the wiping property and the bending resistance of the fingerprint are excellent, and the excellent visibility can be expressed.
Further, the optical laminates obtained in Examples 1 to 5 have excellent surface hardness because the pencil hardness is H or 3H, and have a yellowness of 1.5 or 1.6 and a total light transmittance of 92%. Therefore, transparency is also excellent.

DESCRIPTION OF SYMBOLS 1 ... Optical laminated body 2 ... Resin film 3 ... 1st hard-coat layer 4 ... 2nd hard-coat layer

Claims (11)

A resin film containing a polyimide-based resin, a first hard coat layer laminated on one surface of the resin film, and a single-layer second hard coat laminated on the other surface of the resin film An optical laminate having a layer and
The polyimide resin has the formula (10)

[Wherein, G is a tetravalent organic group, and A is a divalent organic group]
And a repeating structural unit represented by the formula:

[Wherein, G ³ and A ³ are each independently a divalent organic group]
Polyamide imide containing a repeating structural unit represented by
In the MIT bending fatigue test with a bending radius of 3 mm based on ASTM standard D2176-16, the resin film has a number of bending exceeding 100,000, and the first hard coat layer has an oleic acid contact angle of 65 ° or more. , the second hard coat layer, oleic acid contact angle of Ri der less 65 ° or 1 °, the thickness of the thickness and the second hard coat layer of the first hard coat layer, respectively, is 1 to 10 [mu] m, the optical stack . The optical laminate according to claim 1, wherein the resin film has an indentation hardness of 350 N / mm ² or more measured using a nano indenter in a cross section in a thickness direction. The optical laminate according to claim 1, wherein the value of the impact absorption energy by the Charpy impact test is 100 kJ / m ² or more.   The optical laminate according to any one of claims 1 to 3, wherein the polyimide resin has a weight average molecular weight in terms of polystyrene of 50,000 to 1,000,000.   The optical laminate according to claim 1, wherein the polyimide resin contains a fluorine atom.   The optical laminate according to any one of claims 1 to 5, wherein the thickness of the resin film is 20 to 150 µm.   The optical laminate according to any one of claims 1 to 6, wherein the first hard coat layer is a cured product of a curable composition containing a fluorine-containing compound.   The optical laminate according to claim 7, wherein the content of the fluorine-containing compound contained in the curable composition is 0.1 to 5 parts by mass based on the mass of the solid content of the curable composition. The optical laminate according to any one of claims 1 to 8 , wherein a ratio of a thickness of the first hard coat layer to a thickness of the second hard coat layer is 10: 7 to 7:10. The optical laminate according to any one of claims 1 to 9 , wherein yellowness is 5.0 or less. The optical laminate according to any one of claims 1 to 10 , wherein the total light transmittance is 80% or more.

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