KR20200037757A - Optical multilayer body - Google Patents

Abstract

The present invention provides an optical multilayer body which is excellent in finger print wiping properties and bending resistance, and can exhibit excellent visibility. The optical multilayer body comprises: a resin film comprising a polyimide resin; a first hard coating layer laminated on one side of the resin film; and a second hard coating layer laminated on the other side of the resin film. The resin film has a bending frequency of more than 100,000 in the MIT resistance fatigue test having a radius of curvature of 3 mm in accordance with ASTM standard D2176-16. The first hard coating layer has an oleic acid contact angle of 65° or more, and the second hard coating layer has an oleic acid contact angle of 1° or more and less than 65°.

Description

Optical laminate {OPTICAL MULTILAYER BODY}

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

BACKGROUND ART Image display devices such as liquid crystal display devices and organic EL display devices are widely used in various applications such as mobile phones and smart watches, and recently, 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 coating layer laminated on at least one surface of the resin film has been studied (for example, International Publication No. 2017/014287). ). Such an optical laminated body is arrange | positioned via a pressure-sensitive adhesive etc. in the polarizing plate contained in an image display apparatus, for example.

International Publication No. 2017/014287

However, according to the examination of the present inventors, the optical laminate may not have sufficient wiping properties such as fingerprints on the viewer-side surface, and repeated bending of the optical laminate may result in a resin film. Since the interface of the hard coating layer, the interface between the hard coating layer and the pressure-sensitive adhesive, or the like is peeled or deteriorated, it was found that the visibility of the display portion may be lowered.

Accordingly, an object of the present invention is to provide an optical laminate that is excellent in wipeability and flexural resistance, such as fingerprints, and can exhibit excellent visibility.

As a result of careful examination, the inventor of the present invention provides an optical laminate having a resin film, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side, The oleic acid contact angle of the first hard coating layer is 65 ° or more and the oleic acid contact angle of the second hard coating layer is 1 ° or more and less than 65 °, the number of bending of the resin film is more than 100,000 times, or the indentation hardness of the resin film is 350 N / It has been found that the above problem can be solved by setting the value of the shock absorbing energy of the optical layered body to 100 kJ / m 2 or more, and the present invention has been completed.

[1] An optical laminate having a resin film comprising a polyimide-based resin, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side, as a resin film Silver, in the MIT internal fatigue test with a bend radius of 3 mm according to ASTM standard D2176-16, the number of bends exceeds 100,000 times, and the first hard coating layer has an oleic acid contact angle of 65 ° or more, and a second The hard coating layer has an oleic acid contact angle of 1 ° or more and less than 65 °.

[2] An optical laminate having a resin film comprising a polyimide resin, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side, as a resin film Silver, the indentation hardness measured using a nano indenter in the cross-section of the thickness direction is 350 N / mm 2 or more, the first hard coating layer has an oleic acid contact angle of 65 ° or more, and the second hard coating layer has an oleic acid contact angle The optical laminated body which is 1 to 65 degrees.

[3] An optical laminate having a resin film comprising a polyimide-based resin, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side, comprising: The 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 an optical laminate having a value of shock absorption energy by Charpy impact test of 100 kJ / m 2 or more.

[4] The optical laminate according to any one of [1] to [3], wherein the polyimide resin has a weight average molecular weight of 50,000 to 1,000,000 in terms of polystyrene.

[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 with respect to the mass of the solid content of the curable composition.

[9] The optical laminate according to any one of [1] to [8], wherein the thickness of the first hard coating layer and the thickness of the second hard coating layer are 1 to 15 μm, respectively.

[10] The optical laminate according to any one of [1] to [9], wherein the ratio of the thickness of the first hard coating layer to the thickness of the second hard coating layer is 10: 7 to 7:10.

[11] The optical laminate according to any one of [1] to [10], wherein the yellowness is 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 layered product of the present invention is excellent in wiping properties such as fingerprints and bending resistance, and can exhibit excellent visibility.

1 is a schematic cross-sectional view showing an example of a layer configuration in the optical laminate of the present invention.

The optical laminate of the present invention has a resin film comprising a polyimide resin, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side.

[Resin film]

The resin film is made of a polyimide resin.

In one embodiment of the present invention, the resin film is a film in which the number of flexures exceeds 100,000 in the MIT fracture fatigue test with a bend radius of 3 mm according to ASTM standard D2176-16. The number of flexures can be measured in accordance with ASTM standard D2176-16, and can be measured, for example, by the method described in Examples.

Moreover, 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 using a nano indenter in a cross section in the thickness direction. From the viewpoint of easy to increase the mechanical strength of the optical laminate, the indentation hardness is preferably 400 N / mm 2 or more, more preferably 450 N / mm 2 or more, further preferably 500 N / mm 2 or more, particularly preferably Is 550 N / mm 2 or more. The upper limit of the indentation hardness is not particularly limited, but is preferably 800 N / mm 2 or less, more preferably 750 N / mm 2 or less, and still more preferably 700 N / mm 2 or less from the viewpoint of easy to improve the bending resistance. The indentation hardness is the indentation hardness in the cross section in the thickness direction measured using a nano indenter, and can be measured by the method described in Examples, for example. If the number of bending of the resin film exceeds 100,000 or the indentation hardness is 350 N / mm 2 or more, the resin film does not deteriorate even if the optical laminate is repeatedly bent because the resin film has sufficient bending resistance. Also, peeling or deterioration of the interface between the resin film and the first hard coating layer or the second hard coating layer is suppressed, thereby improving the bending resistance and visibility of the optical laminate. In addition, when the optical layered product of the present invention is applied to an image display device, the view side (display side) of the image display device is arranged such that the first hard coating layer and the opposite side to the viewing side become the second hard coating layer. In addition, in this specification, visibility means that it is easy to see when the display portion of the image display device is visually viewed (when the display portion is viewed from the viewer side).

The polyimide-based resin contained in the resin film means a polymer (polyimide, polyamideimide, polyamide) mainly comprising a structural unit containing an imide group and a structural unit containing an amide group. The polyimide has a structural unit containing an imide group, the polyamideimide has a structural unit containing an imide group and a structural unit containing an amide group, and the polyamide has a structural unit containing an amide group. The type of the polyimide-based resin is not particularly limited, and the polyimide-based resin is used so that the number of bending of the resulting resin film exceeds 100,000 or the indentation hardness measured using a nano indenter is 350 N / mm 2 or more. The type of repeating structural unit may be appropriately selected.

In one embodiment of the present invention, the polyimide-based resin can be produced using, for example, a tetracarboxylic acid compound and a diamine compound as main raw materials, and the polyimide-based resin is represented by the following formula (10) Branches have repeating structural units. In formula (10), G is a tetravalent organic group, and A is a divalent organic group. In the present invention, the polyimide-based resin may contain a structure represented by two or more kinds of formulas (10) in which G and / or A are different.

Further, the polyimide-based resin may contain one or more structures selected from structures represented by formulas (11) to (13) within a range that does not impair various physical properties of the resulting resin film. It is preferable that a polyimide-type resin is a polyamideimide containing a repeating structural unit represented by Formula (13) from a viewpoint of easy to improve bending resistance.

In formulas (10) and (11), G and G ¹ each independently represent a tetravalent organic group, and preferably represent 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, and in this case, the number of carbon atoms in the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 to 8. Examples of G and G ¹ include Formula (20), Formula (21), Formula (22), Formula (23), Formula (24), Formula (25), Formula (26), Formula (27), Formula (28), or A group represented by formula (29); A group in which hydrogen atoms in the groups represented by these formulas are substituted by methyl groups, fluoro groups, chloro groups or trifluoromethyl groups; And a tetravalent chain hydrocarbon group having 6 or less carbon atoms.

In the above formula, * represents a bonding hand,

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- 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 thereof include a phenylene group. From the viewpoint of easy to improve the bending resistance of the resulting resin film, G ¹ is preferably a group represented by formulas (26), (28), and (29).

In Formula (12), G ² represents a trivalent organic group, and preferably, the hydrogen atom in the organic group is an organic group which may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. As G ^2, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or formula ( A group in which any one of the bonds of the group represented by 29) is substituted with a hydrogen atom, and a trivalent hydrocarbon group having 6 or less carbon atoms are exemplified.

In Formula (13), G ³ represents a divalent organic group, and preferably a hydrogen atom in the organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. As G ³ , equation (20), equation (21), equation (22), equation (23), equation (24), equation (25), equation (26), equation (27), equation (28) or equation ( Of the group represented by 29), a group in which two nonadjacent groups are substituted with hydrogen atoms and a chain hydrocarbon group having 6 or less carbon atoms are exemplified.

In Formulas (10) to (13), A, A ¹ , A ² and A ³ each independently represent a divalent organic group, and preferably represent a divalent organic group having 4 to 40 carbon atoms. The organic group may have a hydrogen atom in the organic group substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. Examples of A, A ¹ , A ² and A ³ include equation (30), equation (31), equation (32), equation (33), equation (34), equation (35), equation (36), equation (37) Or a group represented by formula (38); A group in which hydrogen atoms in the groups represented by these formulas are substituted by methyl groups, fluoro groups, chloro groups or trifluoromethyl groups; And chain hydrocarbon groups having 6 or less carbon atoms.

In formulas (30) to (38), * represents a bonding hand,

Z ¹ , Z ² and Z ³ are each independently a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ -or -CO-. The bonding position of each ring of Z ¹ and Z ² and the bonding position of each ring of Z ² and Z ³ are, respectively, preferably a meta position or a para position with respect to each ring, more preferably para. Location.

In one embodiment of the present invention, the polyimide-based resin contained in the resin film may include plural kinds of G ³ , and plural kinds of G ³ may be the same or different from each other. Particularly, from the viewpoint of improving the surface hardness and bending resistance of the optical laminate containing a polyimide-based resin as a resin film, at least a part of G ³ is represented by formula (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 the hydrogen atoms contained in R ¹ to R ⁸ are each Independently, it may be substituted with a halogen atom,

B is a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -N (R ⁹ )-represents R ⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbons which may be substituted by a halogen atom,

n is an integer from 0 to 4,

* Represents a bonding hand]

It is preferable that it is a structural unit represented by.

In formula (3), B is each 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 )-, from the viewpoint of improving the bending resistance of the optical laminate, preferably -O- Or -S-, and 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. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and 2-methyl-butyl group. , 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group and the like. Moreover, as a C6-C12 aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, etc. are mentioned, for example. From the viewpoint of surface hardness and flexibility of the optical laminate, R ¹ to R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or 1 to 3 carbon atoms. 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 hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 2-methyl -Butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group, n-heptyl group, n-octyl group, tert-octyl group, n-nonyl group, n-decyl group and the like. And these may be substituted with a halogen atom. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom, and iodine atom.

In Formula (3), n is an integer in the range of 0 to 4, and when n is within this range, the bending resistance and elastic modulus of the optical laminate are good. Moreover, in 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, more preferably 0 or 1, and n is within this range, The flexibility and elastic modulus of the optical laminate are good, and the availability of raw materials is relatively good. In addition, G ³ may contain one or two or more types of structural units represented by Formula (3), from the viewpoint of improving the elastic modulus and flexural resistance of the optical laminate and reducing the yellowness (YI value), In particular, two or more types of structural units having different values of n may preferably contain two types of structural units having different values of n. In that case, it is preferable that n contains both of 0 and 1 structural units from a viewpoint that an optical laminated body is easy to express high elastic modulus, bending resistance, and low yellowness (YI value).

In a preferred embodiment of the present invention, formula (3) is a structural unit or formula (3 ') in which n = 0, R ¹ to R ⁸ are hydrogen atoms:

It is a structural unit represented by, and these can also be used together. In this case, the optical layered body exhibits high surface hardness, and at the same time, can have high bending resistance and can lower yellowness.

In a preferred embodiment of the present invention, the formula (3) when n is 0 to 4 with respect to the sum of the structural units represented by formula (10) and the structural units represented by formula (13) of the polyimide-based resin Content of the structural unit represented by is, Preferably it is 20 mol% or more, More preferably, it is 30 mol% or more, More preferably, it is 40 mol% or more, Especially preferably, it is 50 mol% or more, Most preferably, it is 60 mol. % Or more, preferably 90 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less. Content of the structural unit represented by Formula (3) when n is 0-4 with respect to the sum of the structural unit represented by Formula (10) and the structural unit represented by Formula (13) in a polyimide-type resin mentioned above If it is more than the lower limit of, the optical laminate can exhibit high surface hardness, and may have excellent flexural resistance and elastic modulus. Content of the structural unit represented by Formula (3) when n is 0-4 with respect to the sum of the structural unit represented by Formula (10) and the structural unit represented by Formula (13) in a polyimide-type resin mentioned above If it is less than or equal to the upper limit, the viscosity of the polyimide resin varnish can be suppressed by suppressing the thickening due to hydrogen bonding between the amide bonds derived from formula (3), and processing of the resin film can be facilitated. .

In a preferred embodiment of the present invention, with respect to the sum of the structural units represented by formula (10) and the structural units represented by formula (13) of the polyimide resin, n in formula (3) is represented by 1 to 4 The content of the losing constituent unit is preferably 3 mol% or more, more preferably 5 mol% or more, more preferably 7 mol% or more, particularly preferably 9 mol% or more, and preferably 90 mol% or less , More preferably 70 mol% or less, more preferably 50 mol% or less, particularly preferably 30 mol% or less. With respect to the sum of the structural units represented by formula (10) and the structural units represented by formula (13) in the polyimide-based resin, the content of the structural units represented by n in formula (3) 1 to 4 is the lower limit described above. If it is the above, the optical layered body can express high surface hardness, and also improves bending resistance. With respect to the sum of the structural units represented by formula (10) and the structural units represented by formula (13) in the polyimide-based resin, if the structural units represented by n in formula (3) are 1 to 4 are equal to or less than the above upper limit , By suppressing the thickening due to hydrogen bonding between the amide bonds derived from formula (3), the viscosity of the polyimide-based resin varnish can be suppressed and processing of the resin film can be facilitated. Moreover, content of the structural unit represented by Formula (3) can be measured using ¹ H-NMR, for example, or can be calculated from the introduction ratio of a raw material.

In a suitable embodiment of the present invention, G ³ of the polyimide-based resin, preferably 5 mol% or more, more preferably 8 mol% or more, more preferably 10 mol% or more, particularly preferably 12 Molar% or more is represented by formula (3) when n is 1-4. When the above lower limit of G ³ of the polyimide-based resin is represented by the formula (3) when n is 1 to 4, the optical laminate can exhibit high surface hardness and at the same time have high flex resistance. . Further, G ^{3 in} the polyimide resin, preferably 90 mol% or less, more preferably 70 mol% or less, further preferably 50 mol% or less, particularly preferably 30 mol% or less, n is 1 It is preferable that it is represented by Formula (3) in the case of -4. When the above upper limit of G ³ of the polyimide resin is represented by formula (3) when n is 1 to 4, hydrogen bonding between amide bonds derived from formula (3) when n is 1 to 4 By suppressing the thickening, the viscosity of the polyimide-based resin varnish can be suppressed, and processing of the optical laminate can be facilitated.

In a preferred embodiment of the present invention, the G ³ in the polyimide-based resin is preferably 30 mol% or more, more preferably 50 mol% or more, particularly preferably 70 mol% or more, and n is 0 to It is represented by Formula (3) in the case of 4. When the above-mentioned lower limit value of G ³ of the polyimide-based resin is represented by formula (3) when n is 0 to 4, the optical laminate can exhibit high surface hardness and at the same time have high bending resistance. . Further, the polyimide-based resin in the G ^3, is preferably not more than 100 mol% is preferably represented by the following formula (3) in the case where, n is zero to four. When the lower limit of G ³ of the polyimide-based resin is represented by formula (3) when n is 0 to 4, it is used for hydrogen bonding between amide bonds derived from formula (3) when n is 0 to 4 The viscosity of the polyimide-based resin varnish can be suppressed by suppressing the thickening, and the processing of the optical laminate can be facilitated. Moreover, the ratio of the structural unit represented by Formula (3) in a polyimide-type resin can be measured using ¹ H-NMR, for example, or can be calculated from the introduction ratio of a raw material.

In a preferred embodiment of the present invention, at least a portion of the plurality of A and A ^{3 in} the formulas (10) and (13), 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 the hydrogen atoms contained in R ¹⁰ to R ¹⁷ are each Independently, it may be substituted with a halogen atom, and * represents a bond.]

It is a structural unit represented by. If at least a part of the plurality of A and A ³ in formulas (10) and (13) is a group represented by formula (4), the optical laminate can exhibit high surface hardness and at the same time have high transparency. have.

In formula (4), R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 6 to 12 carbon atoms. 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 examples of 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 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, wherein R ¹⁰ to R ¹⁷ The hydrogen atoms contained 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, from the viewpoint of the surface hardness, transparency and bending resistance of the optical laminate, more preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, particularly preferred Preferably R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are hydrogen atoms, R ¹¹ and R ¹⁷ are hydrogen atoms, methyl group, fluoro group, chloro group or trifluoromethyl group, especially R ¹¹ And R ¹⁷ is preferably a methyl group or a trifluoromethyl group.

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

It is a structural unit represented by, ie, at least a part of the plurality of A and A ³ is a structural unit represented by formula (4 '). In this case, the optical laminate can exhibit high transparency and improve the solubility of the polyimide-based resin in a solvent by using a skeleton containing fluorine elements, and suppress the viscosity of the polyimide-based resin varnish to be low. And can easily process the resin film.

In a preferred embodiment of the present invention, A and A ³ in the polyimide-based resin, preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more of formula (4) ), Particularly represented by formula (4 '). When A and A ^{3 in} the above-mentioned range in the polyimide resin are represented by formula (4), particularly formula (4 '), the optical laminate expresses high transparency and, at the same time, a skeleton containing fluorine element Thereby, the solubility of the polyimide-based resin in a solvent can be improved, the viscosity of the polyimide-based resin varnish can be suppressed low, and the resin film can be easily processed. Further, preferably, 100 mol% or less of A and A ³ in the polyimide resin is represented by formula (4), particularly formula (4 '). A and A ³ in the polyimide-based resin may be formula (4), particularly (4 ′). The ratio of the structural unit represented by Formula (4) of A and A ³ in the polyimide-based resin can be measured, for example, using ¹ H-NMR, or it can be calculated from the introduction ratio of raw materials.

In a preferred embodiment of the present invention, at least a portion of the plurality of Gs in the formula (10) is represented by the formula (5):

[In formula (5), R ¹⁸ -R ²⁵ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁸ to R ²⁵ are each Independently, it may be substituted with a halogen atom, and * represents a bond.]

It is a structural unit represented by. If 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 improves the solubility of the polyimide-based resin in a solvent, and improves the polyimide. The viscosity of the system resin varnish can be suppressed low, and processing of the resin film can be facilitated.

In formula (5), R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 6 to 12 carbon atoms. 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 examples of 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 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, wherein R ¹⁸ to R ²⁵ The hydrogen atoms contained 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 a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoro group, more preferably from the viewpoint of improving the surface hardness, bending resistance, and transparency of the optical laminate. Is a methyl group, even more preferably R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ and R ²⁵ are hydrogen atoms, R ²¹ and R ²² are hydrogen atoms, methyl groups, fluoro groups, chloro groups or trifluoro It is a methyl group, and it is particularly preferable that R ²¹ and R ²² are a methyl group or a trifluoromethyl group.

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

It is a structural unit represented by, ie, at least one part of a some G is a structural unit represented by Formula (5 '). In this case, the optical laminate can have high transparency.

In a suitable embodiment of the present invention, G in the polyimide-based resin, preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more of formula (5), in particular It is represented by the formula (5 '). When G in the above-mentioned range in the polyimide-based resin is represented by formula (5), particularly formula (5 '), the optical laminate can have high transparency, and the polyimide is also formed by a skeleton containing elemental fluorine. The solubility of the mid-based resin in the solvent can be improved, the viscosity of the polyimide-based resin varnish can be suppressed low, and the production of the optical laminate is easy. Moreover, preferably, 100 mol% or less of G in the said polyimide-type resin is represented by Formula (5), especially Formula (5 '). G in the said polyimide resin may be a formula (5), especially (5 '). The ratio of the structural unit represented by Formula (5) of G in the polyimide-based resin can be measured, for example, using ¹ H-NMR, or can be calculated from the introduction ratio of the raw material.

The polyimide-based resin can be obtained, for example, by polycondensation of a diamine compound and a tetracarboxylic acid compound (tetracarboxylic acid anhydride, etc.), for example, Japanese Patent Application Laid-open No. 2006-199945 or Japan It can be synthesized according to the method described in Japanese Patent Application Laid-open No. 2008-163107. As a commercial item of polyimide, Mitsubishi Gas Chemical Co., Ltd. Neopurim (registered trademark), Kawamura Industry Co., Ltd. KPI-MX300F, etc. may be mentioned.

In a preferred embodiment of the present invention, a polyimide having a repeating structural unit represented by formula (10) can be obtained by reacting a diamine compound and a tetracarboxylic acid compound, and repeating structural units and formula represented by formula (10) The polyamideimide having a repeating structural unit represented by (13) can be obtained by reacting a diamine compound with a tetracarboxylic acid compound and then reacting a dicarboxylic acid compound, and the repeating structure represented by formula (13) The polyamide having a unit 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-based resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic acid and anhydrides thereof, preferably dihydrates thereof; Aliphatic tetracarboxylic acid compounds, such as aliphatic tetracarboxylic acid and its anhydride, Preferably its dihydride, etc. are mentioned. In addition to the anhydride, the tetracarboxylic acid compound may be a derivative of a tetracarboxylic acid compound such as acid chloride, and these may be used alone or in combination of two or more.

Specific examples of the aromatic tetracarboxylic acid anhydride include non-condensed polycyclic aromatic tetracarboxylic acid anhydride, monocyclic aromatic tetracarboxylic acid anhydride, and condensed polycyclic aromatic tetracarboxylic acid anhydride. As non-condensed polycyclic aromatic tetracarboxylic acid anhydride, 4,4'-oxydiphthalic acid 2 anhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic acid anhydride, 2,2', 3,3 ' -Benzophenone tetracarboxylic acid anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic acid anhydride (sometimes referred to as BPDA), 2,2', 3,3'-biphenyltetracar Main acid 2 anhydride, 3,3 ', 4,4'-diphenylsulfonetetracarboxylic acid 2 anhydride, 2,2-bis (3,4-dicarboxyphenyl) propane 2 anhydride, 2,2-bis (2,3 -Dicarboxyphenyl) propane 2 anhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane 2 anhydride, 4,4 '-(hexafluoro isopropylidene) diphthalic acid 2 anhydride (labeled 6FDA In some cases), 1,2-bis (2,3-dicarboxyphenyl) ethane 2 anhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane 2 anhydride, 1,2-bis (3, 4-dicarboxyphenyl) ethane 2 anhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane 2 anhydride, bis (3,4-dicarboxype) ) Methane 2 anhydride, bis (2,3-dicarboxyphenyl) methane 2 anhydride, 4,4 '-(p-phenylenedioxy) diphthalic acid 2 anhydride, 4,4'-(m-phenylenedioxy) diphthalic acid 2 anhydride. Moreover, 1,2,4,5-benzenetetracarboxylic acid 2 anhydride is mentioned as monocyclic aromatic tetracarboxylic acid anhydride, and as a condensed polycyclic aromatic tetracarboxylic acid 2 anhydride, 2,3,6,7- Naphthalene tetracarboxylic acid 2 anhydride is mentioned.

Among these, 4,4'-oxydiphthalic acid 2 anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid 2 anhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid 2 are preferred. Anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic acid 2 Anhydride, 2,2', 3,3'-biphenyltetracarboxylic acid 2 anhydride, 3,3 ', 4,4'-diphenyl Sulfontetracarboxylic acid anhydride, 2,2-bis (3,4-dicarboxyphenyl) propane 2 anhydride, 2,2-bis (2,3-dicarboxyphenyl) propane 2 anhydride, 2,2-bis (3 , 4-dicarboxyphenoxyphenyl) propane 2 anhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic acid 2 anhydride, 1,2-bis (2,3-dicarboxyphenyl) ethane 2 anhydride, 1 , 1-bis (2,3-dicarboxyphenyl) ethane 2 anhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane 2 anhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane 2 anhydride, bis (3,4-dicarboxyphenyl) methane 2 anhydride, bis (2,3-dicarboxyphenyl) methane 2 anhydride, 4,4 '-(p-phenylenedioxy) diphthalic acid 2 no Water and 4,4 '- there may be mentioned (m- phenylenedimaleimide oxy) diphthalic acid dianhydride. These may be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic acid anhydride include cyclic or acyclic aliphatic tetracarboxylic acid anhydride. The cyclic aliphatic tetracarboxylic acid anhydride is tetracarboxylic acid anhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic acid anhydride and 1,2,3,4-cyclo Cycloalkanetetracarboxylic acid anhydride, such as butanetetracarboxylic acid anhydride, 1,2,3,4-cyclopentanetetracarboxylic acid anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5 , 6-tetracarboxylic acid anhydride, dicyclohexyl-3,3 ', 4,4'-tetracarboxylic acid anhydride, and positional isomers thereof. These may be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic acid anhydride include 1,2,3,4-butanetetracarboxylic acid anhydride, 1,2,3,4-pentanetetracarboxylic acid anhydride, and the like, alone or It can be used in combination of two or more. Moreover, you may use combining cyclic aliphatic tetracarboxylic acid anhydride and acyclic aliphatic tetracarboxylic acid anhydride.

Among the tetracarboxylic acid compounds, preferably from the viewpoint of high transparency and low colorability, the alicyclic tetracarboxylic acid anhydride or the non-condensed polycyclic aromatic tetracarboxylic acid anhydride is mentioned. Specific examples include 4,4'-oxydiphthalic acid 2 anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid 2 anhydride, 3,3', 4,4'-biphenyltetracarboxylic acid 2 anhydride, 2 , 2 ', 3,3'-biphenyltetracarboxylic acid anhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid anhydride, 2,2-bis (3,4-dicarboxyphenyl) Propane 2 anhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic acid 2 anhydride and mixtures thereof are preferred.

Moreover, in the range which does not impair the various physical properties of the obtained transparent resin film, the polyimide-type resin in this invention is a tricarboxylic acid compound and dicarboxylic acid in addition to the tetracarboxylic acid compound used for the said polyimide synthesis. You may use it combining a compound further.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acid, aliphatic tricarboxylic acid and derivatives thereof (for example, acid chloride, acid anhydride, etc.), and specific examples thereof include 1,2,4-benzenetricarboxylic acid anhydride; 2,3,6-naphthalene tricarboxylic acid-2,3-anhydride; And a compound in which phthalic anhydride and benzoic acid are connected by a single bond, -O-, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ -or a phenylene group. . These tricarboxylic acid compounds may be used alone or in combination of two or more.

Examples of the dicarboxylic acid compound include aromatic dicarboxylic acid, aliphatic dicarboxylic acid and derivatives thereof (for example, acid chloride, acid anhydride, etc.), and specific examples thereof include terephthalic acid; Isophthalic acid; Naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; Chain hydrocarbons having 8 or less carbon atoms, dicarboxylic acid compounds and two benzoic acid single bonds, -O-, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- Or the compound connected by the phenylene group, and these acid chloride compounds are mentioned. Among these dicarboxylic acid compounds, 4,4'-oxybisbenzoic acid and their acid chlorides are preferable, and terephthaloyl chloride and 4,4'-oxybis (benzoyl chloride) are more preferable. These dicarboxylic acid compounds may be used alone or in combination of two or more.

The diamine compound used for the synthesis of the polyimide-based resin may be an aliphatic diamine, an aromatic diamine, or a mixture thereof. In addition, in this specification, "aromatic diamine" means the diamine compound in which the amino group is directly bonded to the aromatic ring, and may contain an aliphatic group or other substituents in a part of the structure. The aromatic ring may be a monocyclic ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring and a fluorene ring, but are not limited thereto. Among these, it is preferably a benzene ring. Moreover, "aliphatic diamine" refers to a diamine compound in which an amino group is directly bonded to an aliphatic group, and an aromatic ring or other substituent may be included in a part of the structure.

As the aliphatic diamine, for example, acyclic aliphatic diamines such as hexamethylenediamine and 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, norbornanediamine, 4,4 And cyclic aliphatic diamines such as' -diaminodicyclohexylmethane, and these may 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, 2,6- Aromatic diamines having one aromatic ring, such as diaminonaphthalene; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-dia Minodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis (4-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2- Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2'-dimethylbenzidine, 2,2'-bis (tri Fluoromethyl) -4,4'-diaminodiphenyl (sometimes referred to as TFMB), 4,4'-bis (4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) ) Fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9,9-bis (4-amino-3-chlorophenyl) fluorene, 9,9-bis (4-amino-3) -A direction having two or more aromatic rings, such as fluorophenyl) fluorene A group diamine is mentioned. These may be used alone or in combination of two or more.

Among the diamine compounds, it is preferable to use one or more kinds selected from the group consisting of aromatic diamines having a biphenyl structure from the viewpoint of high transparency and low colorability.

The polyimide-based resin is a diamine compound, a tetracarboxylic acid compound (a tetracarboxylic acid compound derivative such as an acid chloride compound, tetracarboxylic acid anhydride), and optionally a tricarboxylic acid compound (acid chloride compound, tricarboxylic acid anhydride) It is a condensation-type polymer which is a polycondensation product of at least 1 compound selected from the group which consists of tricarboxylic acid compound derivatives, etc.) and dicarboxylic acid compounds (dicarboxylic acid compound derivatives, such as an acid chloride compound). The repeating structural unit represented by formula (11) is usually derived from a diamine compound and a tetracarboxylic acid compound. The repeating structural unit represented by formula (12) is usually derived from a diamine compound and a tricarboxylic acid compound. The repeating structural unit represented by formula (13) is usually derived from a diamine compound and a dicarboxylic acid compound. Specific examples of the diamine compound, the tetracarboxylic acid compound, the dicarboxylic acid compound, and the tricarboxylic acid compound are as described above.

The polyimide-based 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-based resin is preferably 50,000 or more, more preferably 100,000 or more, more preferably 200,000 or more, particularly preferably 300,000 or more, preferably 1,000,000 or less, more preferably 750,000 or less , More preferably 600,000 or less, particularly preferably 500,000 or less. When the weight average molecular weight of the polyimide resin is greater than or equal to the above lower limit, the bending resistance of the resin film made of the polyimide resin is improved, and even when the optical laminate is repeatedly bent, excellent visibility is easily exhibited. Moreover, if the weight average molecular weight of the polyimide-based resin is less than or equal to the above upper limit, the viscosity of the polyimide-based resin varnish can be suppressed low, and since the film formation of the resin film is easy, the processability becomes good. In addition, in this specification, the weight average molecular weight can be calculated | required by standard polystyrene conversion by performing GPC measurement, for example, and can specifically be calculated | required by the method described in the Example.

It is preferable that the polyimide resin 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 yellowness can be reduced while increasing the bending resistance of the resin film, and thus it is easy to improve the visibility of the optical laminate.

The content of the halogen atom in the polyimide-based resin is based on the mass of the polyimide-based resin from the viewpoint of reducing the yellowness of the optical laminate, that is, improving transparency and exhibiting excellent visibility. It is preferable that it is -40 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 even more preferably 80% by mass or more with respect to the mass of the resin film. , And may be 100% by mass. When the content of the polyimide resin is greater than or equal to the above lower limit, the bending resistance of the resin film becomes good, and even when bending of the optical laminate is repeated, excellent visibility is easily exhibited.

When the polyimide-based resin is polyamideimide, the content of the structural unit represented by formula (13) is preferably 0.1 mol or more, more preferably 0.5 with respect to 1 mol of the structural unit represented by formula (10). It is mol or more, more preferably 1.0 mol or more, particularly preferably 1.5 mol or more, preferably 6.0 mol or less, more preferably 5.0 mol or less, and more preferably 4.5 mol or less. When the content of the structural unit represented by formula (13) is greater than or equal to the above lower limit, the optical layered body can express higher surface hardness. Moreover, when content of the structural unit represented by Formula (13) is below the said upper limit, the thickening by hydrogen bonding between amide bonds in Formula (13) can be suppressed, and the viscosity of the polyimide resin varnish can be reduced, and optical It is easy to manufacture a laminate.

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

The content of the silica particles is usually 0.1 mass%, preferably 1 mass% or more, more preferably 5 mass% or more, still more preferably 10 mass% or more, and particularly preferably 30 mass% with respect to the mass of the resin film. % Or more, preferably 60% by mass or less. When the content of the silica particles is greater than or equal to the above lower limit, the bending resistance is more easily improved. When the content of the silica particles is less than or equal to the above upper limit, the optical properties are improved, for example, the yellowness is easily reduced. Therefore, if it is the said range, even if bending of an optical laminated body is repeated, it is easy to express excellent visibility.

The resin film contained in the optical laminate of the present invention may further contain an ultraviolet absorber. Examples of the ultraviolet absorber include triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. 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, Adekastab (registered trademark) LA-31 manufactured by ADEKA, and BASF Japan Corporation. And Tinuvin (registered trademark) 1577. When the ultraviolet absorber is contained, deterioration of the resin film is suppressed, so it is easy to increase the optical properties of the optical laminate. 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 within the above range, it is easy to further improve the optical properties of the resin film.

The optical film of the present invention may further contain a colorant. The content of the colorant can be appropriately selected depending on the purpose, the type of colorant, and the like. When a blueing agent is used as the colorant, the content thereof 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, it is 50 ppm or less. Known blueing agents can be used as appropriate, for example, each product name is Macrolex (registered trademark) Blue RR (manufactured by Bayer), Macrolex Blue 3R (manufactured by Bayer), Sumiplast (registered trademark) Violet B (Manufactured by Sumika Chemtex Co., Ltd.) and polysynthren (registered trademark) blue RLS (manufactured by Clariant), Diaresin Violet D, Diaresin Blue G, Diaresin Blue N (above, manufactured by Mitsubishi Chemical Corporation). have.

The resin film may contain other additives in addition to inorganic particles, an ultraviolet absorber, and a colorant, within a range that does not impair the effects of the present invention. Examples of other additives include mold 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 relative to the mass of the resin film. Moreover, you may adjust the bending | flexion frequency of a resin film to 100,000 times or indentation hardness to 350 N / mm <2> or more by adjusting the kind or content of a polyimide-type resin and / or the kind or content of an additive.

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 even more preferably 30 to 90 μm. In addition, in the present invention, the thickness of the resin film can be measured by the method described in Examples.

[First hard coating layer]

In the optical laminate of the present invention, the first hard coating layer is laminated on one side of the resin film, and the oleic acid contact angle of the layer surface is 65 ° or more. Therefore, the optical laminate of the present invention has excellent wipeability against contamination such as fingerprints adhered by a user contacting the surface of the first hard coating layer. In the present specification, the wipeability refers to whether or not the wipeability is determined by reciprocating wiping using a test paper for wiping tissue paper or the like with respect to contamination of a predetermined amount of fingerprints, etc. It means that it can be wiped against contamination such as fingerprints by reciprocating wiping about 1 to 4 times using a test paper for wiping.

As described above, the optical laminate of the present invention is excellent in wipeability of the surface of the first hard coating layer disposed on the viewer side of the image display device, and can be easily wiped off without remaining on the display unit even if contamination such as fingerprints is attached. It can express excellent visibility.

The oleic acid contact angle of 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 greater than the above lower limit, the wipeability of a fingerprint or the like increases, and visibility is further improved.

The first hard coating layer is not particularly limited as long as the oleic acid contact angle of the layer surface is 65 ° or more, but is preferably a cured product of a curable composition (sometimes referred to as a curable composition (X)) containing a curable compound.

In the optical layered product of the present invention, the curable composition (X) constituting the first hard coating layer is a polyfunctional compound (curable compound) from the viewpoint of easy to increase the transparency, surface hardness, bending resistance and visibility of the optical layered product. It is preferable to include a meth) acrylate compound.

The polyfunctional (meth) acrylate compound means a compound having two or more (meth) acryloyloxy groups in the molecule. Here, in this specification, the term "(meth) acrylate" means "acrylate" or "methacrylate", and the term "(meth) acryloyl" is similarly referred to as "acryloyl" or " Methacryloyl ”.

The polyfunctional (meth) acrylate compound may contain one or more polyfunctional (meth) acrylate compounds. Moreover, when two or more types of polyfunctional (meth) acrylate compounds are included, the number of (meth) acryloyloxy groups may be the same or different between each polyfunctional (meth) acrylate compound.

As a polyfunctional (meth) acrylate compound, for example, a bifunctional (meth) acrylate monomer, a trifunctional (meth) acrylate monomer, a tetrafunctional (meth) acrylate monomer, a 5-functional or higher (meth) acrylate monomer, And urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and epoxy (meth) acrylate oligomers. These polyfunctional (meth) acrylate compounds may 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, the 3 A functional monomer, the tetrafunctional monomer, the bifunctional monomer, the trifunctional monomer, the tetrafunctional monomer, or a 5-functional or higher monomer can be combined.

The bifunctional (meth) acrylate monomer is a monomer having two (meth) acryloyloxy groups in the molecule, and examples thereof include ethylene glycol di (meth) acrylate, 1,3-butanedioldi (meth) acrylate, and 1 Alkylene such as, 4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate and neopentyl glycol di (meth) acrylate Glycol 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) acrylate, poly Polyoxyalkylene glycol di (meth) acrylates such as propylene glycol di (meth) acrylate and polytetramethylene glycol di (meth) acrylate; Di (meth) acrylates of halogen-substituted alkylene glycols such as tetrafluoroethylene glycol di (meth) acrylate; Di (meth) acrylates of aliphatic polyols such as trimethylolpropanedi (meth) acrylate, ditrimethylolpropanedi (meth) acrylate, and pentaerythritol di (meth) acrylate; Hydrogenated dicyclopentadiene such as hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate or di (meth) acrylate of tricyclodecanedialkanol; Dioxane glycol such as 1,3-dioxane-2,5-diyldi (meth) acrylate [alias: dioxan glycol di (meth) acrylate] or di (meth) acrylate of dioxan dialkanol; Di (meth) acrylates of alkylene oxide adducts of bisphenol A or bisphenol F, such as bisphenol A ethylene oxide adduct diacrylate, bisphenol F ethylene oxide adduct diacrylate, and the like; Bisphenol A or bisphenol F epoxydi (meth) acrylates such as bisphenol A diglycidyl ether acrylic acid adducts and bisphenol F diglycidyl ether acrylic acid adducts; Silicone di (meth) acrylate; Di (meth) acrylate of hydroxypivalic acid neopentyl glycol ester; 2,2-bis [4- (meth) acryloyloxyethoxyethoxyphenyl] propane; 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane; Di (meth) acrylate of 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 the molecule, and examples thereof include glycerin tri (meth) acrylate, trimethylol propane tri (meth) acrylate, and ditrimethylolpropane. Tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate and acid anhydride reactant, caprolactone modified trimethylolpropanetri (meth) acrylate, caprolactone modified pentaerythritol tree ( Meth) acrylate, isocyanurate tri (meth) acrylate, caprolactone modified pentaerythritol tri (meth) acrylate, and reactants of acid anhydrides. Among these, trimethylolpropane tri (meth) acrylate is preferable from the viewpoint of easy to increase the transparency, surface hardness, bending resistance and visibility of the optical laminate of the present invention. These trifunctional (meth) acrylate monomers may 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 ditrimethylolpropanetetra (meth) acrylate, pentaerythritoltetra (meth) acrylate, and dipenta Erythritol tetra (meth) acrylate, tripentaerythritol tetra (meth) acrylate, caprolactone modified pentaerythritol tetra (meth) acrylate, caprolactone modified tripentaerythritol tetra (meth) acrylate, and the like. Among these, pentaerythritol tetra (meth) acrylate is preferable from the viewpoint of easy to increase the transparency, surface hardness, bending resistance and visibility of the optical laminate of the present invention. These tetrafunctional (meth) acrylate monomers may be used alone or in combination of two or more.

Examples of the pentafunctional or higher (meth) acrylate monomer include a reactant of dipentaerythritol penta (meth) acrylate, tripentaerythritol penta (meth) acrylate, dipentaerythritol penta (meth) acrylate and acid anhydride , 5 functions such as reactant of caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified tripentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate and acid anhydride ( Meth) acrylate monomers; Six functions (dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, caprolactone modified tripentaerythritol hexa (meth) acrylate) Meth) acrylate monomers; Tripentaerythritol hepta (meth) acrylate, reactant of tripentaerythritol hepta (meth) acrylate and acid anhydride, caprolactone modified tripentaerythritol hepta (meth) acrylate, caprolactone modified tripentaerythritol hepta (meth) acrylic 7-functional (meth) acrylate monomers, such as a reaction product of a rate and an acid anhydride; And an 8-functional (meth) acrylate monomer such as tripentaerythritol octa (meth) acrylate and caprolactone-modified tripentaerythritol octa (meth) acrylate. These 5-functional or higher (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 of easy to increase the transparency, surface hardness, bending resistance and visibility of the optical laminate of the present invention, the polyfunctional (meth) acrylate compound is the tetrafunctional (meth) acrylate Monomer and the trifunctional (meth) acrylate monomer are included. 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, and more preferably 1 part by mass of the tetrafunctional (meth) acrylate monomer. Is 0.5 to 1.5 parts by mass, particularly preferably 0.9 to 1.1 parts by mass. When the content of the tetrafunctional (meth) acrylate monomer to the content of the trifunctional (meth) acrylate monomer is within the above range, it is easy to increase the transparency, surface hardness, bending resistance, and visibility of the optical laminate.

In the curable composition (X) constituting the first hard coating layer, the content of the polyfunctional (meth) acrylate compound is preferably 50 parts by mass or more with respect to 100 parts by mass of the solid content of the curable composition. When the content of the polyfunctional (meth) acrylate monomer is within the above range, the transparency, surface hardness and visibility of the optical laminate are more likely to be improved. In addition, in this specification, solid content of a curable composition means the composition remove | excluding the solvent from the curable composition when a solvent is contained in a curable composition.

It is preferable that the curable composition (X) constituting the first hard coating layer contains a surface adjusting agent that lowers the surface tension of the first hard coating layer, and a fluorine-containing compound is particularly preferable as the surface adjusting agent. The surface modifier is also called a leveling agent, antifoaming agent, surfactant, and surface tension modifier depending on its action. The oleic acid contact angle on the surface of the first hard coat layer can be set to 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 higher the oleic acid contact angle tends to be. In addition, by adjusting the type and content of other components included in the curable composition (X), the oleic acid contact angle can be adjusted to 65 ° or more, and in this case, the effect of the present invention can be obtained.

When the curable composition (X) constituting the first hard coating layer contains a fluorine compound, the wipeability of fingerprints, etc. on the surface of the first hard coating layer is easily improved, and the surface of the first hard coating layer is smoothed, and the slipperiness of the surface This can be good. In addition, since the wettability of the curable composition (X) to the substrate is high, and the coating film formed by applying the curable composition (X) can prevent the occurrence of coating film defects such as cising and stains. 1 It becomes advantageous from the point of bending resistance of the optical laminated body containing a hard coating layer.

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

As a specific example of a fluorine-containing compound, For example, "BYK (trademark) -340" by BIC (BYK) Chemical Japan company; Neoter's FTERGENT (registered trademark) "222F", "601AD", "601ADH2", and "650AC"; Mega Park (registered trademark) "R-08", "R-30", "R-90", "F-410", "F-411", "F-443", and "F" manufactured by DIC Corporation -445 "," F-470 "," F-471 "," F-477 "," F-479 "," F-482 "," F-483 "; AGC Chemical's Surflon (registered trademark) "S-381", "S-382", "S-383", "S-393", "SC-101", and "SC" -105 "," KH-40 "," SA-100 "; Mitsubishi Material Electronic Chemical Co., Ltd. "Ftop (FTOP) (registered trademark) EF301", "Ftop EF303", "Ftop EF351", "Ftop EF352"; Osaka Organic Chemical Co., Ltd. "V-8FM", Daikin Industries Co., Ltd. "OPTOOL (registered trademark) DAC" and the like. These fluorine-containing compounds may be used alone or in combination of two or more.

When the curable composition (X) constituting the first hard coating layer contains a fluorine-containing compound, the content of the fluorine-containing compound is preferably 0.1 parts by mass or more, more preferably with respect to the mass of the solid content of the curable composition (X) Preferably it is 0.2 mass part or more, More preferably, it is 0.3 mass part or more, Preferably it is 5 mass parts or less, More preferably, it is 4 mass parts or less, More preferably, it is 3 mass parts or less. When the content of the fluorine-containing compound is greater than or equal to the above lower limit, it is easy to improve the wipeability, antifouling properties, smoothness of fingerprints and the like on the surface of the first hard coating layer, and the bending resistance of the optical laminate. Moreover, when content of a fluorine-containing compound is below the said upper limit, it is easy to improve the bending resistance of an optical laminated body.

The curable composition (X) constituting the first hard coating layer may contain 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 light, X-rays, and electron beams. Specific examples include acetophenone, 3-methylacetophenone, and benzyldimethyl Ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 Acetophenone-based initiators such as -one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; Benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4,4'-diaminobenzophenone; Alkylphenone-based initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one and 1-hydroxy-cyclohexyl-phenyl-ketone; Benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; Thioxanthone type initiators, such as 4-isopropyl thioxanthone; Acylphosphine oxide-based initiators such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; Others include xanthone, fluorenone, camperquinone, benzaldehyde, and anthraquinone. These photopolymerization initiators may be used alone or in combination of two or more. Among these photopolymerization initiators, alkylphenone-based initiators and acylphosphine oxide-based initiators are preferable. The photopolymerization initiator may be used alone or in combination of two or more.

When the curable composition (X) includes a photopolymerization initiator, the content of the photopolymerization initiator is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, more preferably 100 parts by mass of the total amount of the curable compound. It is 1 to 5 parts by mass. When the content of the photopolymerization initiator is greater than or equal to the above lower limit, polymerization initiation ability is sufficiently exhibited, and 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 becomes difficult to remain, and it becomes easy to suppress a decrease in visible light transmittance and the like.

The curable composition (X) constituting the first hard coating layer may contain other additives than the polyfunctional (meth) acrylate compound, the fluorine-containing compound, and the photopolymerization initiator, if necessary. Examples of other additives include, for example, monofunctional (meth) acrylate compounds, polyfunctional urethane acrylate monomers and polymers, inorganic particles such as silica particles as described in the [Resin Film], ultraviolet absorbers, antistatic agents, stabilizers, Antioxidants, colorants, surface modifiers that do not contain fluorine atoms described later, and the like. The additives may be used alone or in combination of two or more. The content of the additive is preferably about 0.01 to 20% by mass relative to the mass of the solid content of the curable composition.

The curable composition (X) constituting the first hard coating layer may further contain a solvent in order to apply it on the resin film. The solvent includes, for example, 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; It can be appropriately selected from esterified glycol ethers such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. These solvents may be used alone or in combination of two or more. The type and content of the solvent is appropriately selected depending on the type and content of the components contained in the curable composition, the material, shape, coating method of the resin film, the thickness of the first hard coating layer, etc., for example, the content of the solvent is curable With respect to 100 parts by mass of the total amount of components contained in the composition, 10 to 10,000 parts by mass, preferably 20 to 1,000 parts by mass, more preferably 20 to 100 parts by mass may be sufficient.

The curable composition (X) constituting the first hard coating layer is, for example, the polyfunctional (meth) acrylate compound, the fluorine-containing compound, the photopolymerization initiator, the solvent and, if necessary, other additives commonly used It is obtained by mixing by a method of, for example, stirring. The mixing order and the like are not particularly limited.

The first hard coating layer is obtained by curing the curable composition (X). The thickness of the first hard coating 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 surface hardness is likely to be improved.

[2nd hard coating layer]

In the optical layered body of the present invention, the second hard coating layer is laminated on the surface of the resin film on the opposite side to the first hard coating layer, and the oleic acid contact angle of the layer surface is 1 ° or more and less than 65 °. 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 if bending is repeated, peeling of the interface between the second hard coating layer and the adhesive can be effectively suppressed. , It can express excellent visibility.

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

The second hard coating layer is not particularly limited as long as the oleic acid contact angle on the surface of the layer is 1 ° or more and less than 65 °, but is not particularly limited. desirable.

In the optical laminate of the present invention, the curable composition (Y) constituting the second hard coating layer is a polyfunctional (meth) acrylic as a curable compound from the viewpoint of easy to increase the transparency, bending resistance and visibility of the optical laminate. It is preferred to include a rate compound. As a polyfunctional (meth) acrylate compound, the thing similar to the polyfunctional (meth) acrylate compound exemplified in the term of [1st hard coating layer] is mentioned, preferable polyfunctional (meth) acrylate compound and combinations thereof, The same is true for the range of proportions of polyfunctional (meth) acrylate compounds.

The curable composition (Y) constituting the second hard coating layer may contain the fluorine-containing compound according to the section of [First Hard Coating Layer], but adjusts the oleic acid contact angle of the surface of the second hard coating layer to 1 ° or more and less than 65 ° It is preferable to contain the surface adjuster which does not contain a fluorine atom from a viewpoint of being easy to do. As such a surface adjuster, a polysiloxane compound, a poly (meth) acrylate compound, etc. are mentioned, for example. 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 modifiers may be used alone or in combination of two or more. Moreover, the oleic acid contact angle can be adjusted in the range of 1 ° or more and less than 65 ° by adjusting the type and content of the surface-adjusting agent and the type or content of other components contained in the curable composition (Y). Moreover, by adjusting the kind and content of other components contained in the curable composition (Y), the oleic acid contact angle can be adjusted to 1 ° or more and less than 65 °, and in this case, the effect of the present invention can be obtained.

Surface modifiers, such as polysiloxane compounds and poly (meth) acrylate compounds, improve the wettability of the curable composition (Y) to the substrate, and the coating film formed by applying the curable composition (Y) may be used for coating film defects such as seeding or staining. Since it is possible to prevent the occurrence, it is advantageous from the viewpoint of bending resistance of the optical laminate including the second hard coating layer. In addition, surface modifiers such as polysiloxane compounds and poly (meth) acrylate compounds also increase the wettability of the surface of the second hard coating layer. The adhesion of can be improved. Therefore, even if bending is repeated, peeling of the interface between the second hard coating layer and the pressure-sensitive adhesive can be effectively suppressed, and excellent visibility is easily exhibited.

As a polysiloxane compound, it is Formula (41), for example.

[In formula (41), R ⁴¹ -R ⁴⁹ each independently represent a C1-C20 alkyl group, and L ⁴¹ is a C1-C20 aralkyl group, (meth) acryloyl group, hydroxyl group, carboxyl group , Mercapto group, amino group, epoxy group, polyether structure site, or polyester structure site, and a and b are each an arbitrary integer of 1 or more, and 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 the arrangement in the structure of the polysiloxane compound of the [(R ⁴⁵ ) (L ⁴¹ ) SiO] unit and the [(R ⁴⁶ ) (R ⁴¹ ) SiO] unit is arbitrary)

The polysiloxane compound represented by is mentioned.

In the formula (41), examples of the alkyl group having 1 to 20 carbon atoms of R ⁴¹ to R ⁴⁹ include, for example, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group, And a pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group. Among these, a methyl group, an ethyl group, etc. are preferable as the alkyl group having 1 to 20 carbon atoms of R ⁴² to R ⁴⁹ , and a methyl group, an ethyl group, a decyl group, etc. are preferable as the alkyl group having 1 to 20 carbon atoms of R ⁴¹ .

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

In Formula (41), the polyester structure site of L ⁴¹ represents a site having a polyester structure, and the polyether structure site represents a site having a polyether structure.

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

Although it does not specifically limit as a specific example of a polysiloxane compound, For example, "BYK-300", "BYK-306", "BYK-307", "BYK-310", "BYK-310" manufactured by Big Chemical Japan Corporation , "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-Silclean3700 "," BYK-Silclean3720 "; Momentive Corporation's "TSF410", "TSF411", "TSF4700", "TSF4701", "XF42-B0970", "TSF4730", "YF3965", "TSF4421", "XF42-334", "XF42-B3629" , "XF42-A3161", "TSF4440", "TSF4441", "TSF4445", "TSF4450", "TSF4446", "TSF4452", "TSF4460" and the like. These polysiloxane compounds may be used alone or in combination of two or more.

As a poly (meth) acrylate compound, it is Formula (42), for example.

[In formula (42), R ⁵⁰ represents a hydrogen atom or a methyl group, L ⁴² represents a C1-C20 alkyl group, a polyether structure site, a polyester structure site, or a metal atom, c is an integer of 1 or more, When c is an integer of 2 or more, R ⁵⁰ and L ⁴² may be the same or different, respectively]

And polymers or copolymers containing structural units represented by.

In the formula (42), examples of the alkyl group having 1 to 20 carbon atoms in L ⁴² include those similar to the alkyl group having 1 to 20 carbon atoms in R ⁴¹ to R ⁴⁹ in formula (41).

In Formula (42), the polyester structure site of L ⁴² represents a site having a polyester structure, and the polyether structure site represents a site having a polyether structure.

In Formula (42), examples of the metal atom of L ⁴² include a sodium atom, a potassium atom, and a lithium atom.

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

Although it does not specifically limit as a specific example of a poly (meth) acrylate compound, For example, "BYK-350", "BYK-352", "BYK-353", "BYK-353", "BYK-354" manufactured by Big Chemical Japan, "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381", "BYK-392" and the like. These poly (meth) acrylate compounds may be used alone or in combination of two or more.

When the curable composition (Y) constituting the second hard coating layer contains a surface-adjusting agent, the content of the surface-adjusting agent is preferably from 0.01 to 10% by mass, more preferably from the solid content of the curable composition (Y). Is 0.05 to 5% by mass, more preferably 0.1 to 3% by mass. When the content of the surface modifier is within the above range, it is easy to improve the bending resistance and visibility of the optical laminate.

The curable composition (Y) constituting the second hard coating layer may contain a photopolymerization initiator. As a photoinitiator, the thing similar to the photoinitiator demonstrated in the term of [1st hard coating layer] is mentioned, and the range of a preferable photoinitiator and its content (rate) is also the same.

The curable composition (Y) constituting the second hard coating layer may contain other additives other than the polyfunctional (meth) acrylate compound, the surface modifier, and the photopolymerization initiator. Examples of the other additives include those similar to those of the other additives exemplified in the section of [First Hard Coating Layer], and the ranges of other additives and their content (rate) are also the same.

The curable composition (Y) constituting the second hard coating layer may further contain a solvent in order to apply it on the resin film. As a solvent, the thing similar to the solvent illustrated in the term of [1st hard coating layer] is mentioned, and the range of content (rate) of a solvent is also the same.

The curable composition (Y) constituting the second hard coating layer is, for example, the polyfunctional (meth) acrylate compound, the surface modifier, the photopolymerization initiator and the solvent, by a conventional method, for example, stirring, etc. It is obtained by mixing. The mixing order and the like are not particularly limited.

The second hard coating layer is obtained by curing the curable composition (Y). The thickness of the second hard coating layer is preferably 1 to 15 μm, more preferably 2 to 10 μm. When the thickness of the second hard coating layer is within the above range, the bending resistance of the optical laminate is improved, and even when bending of the optical laminate is repeated, excellent visibility is easily exhibited, and surface hardness is likely to be improved.

In one embodiment of the present invention, the ratio of the thickness of the first hard coating layer and the thickness of the second hard coating layer (first hard coating layer: second hard coating layer) is preferably 10: 7 to 7:10, and 10: It is more preferable that it is 8-8: 10, it is more preferable that it is 10: 9-9: 10, and it is especially preferable that it is 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 likely to be improved, and even after bending the optical laminate repeatedly, it is easy to develop more excellent visibility. Lose.

Although the manufacturing method of the optical laminated body of this invention is not specifically limited, An example of the manufacturing method in the preferable aspect of this invention is shown below.

The optical laminate of the present invention includes the following steps;

(a) a step of forming a coating film by applying a liquid containing polyimide resin (sometimes referred to as a polyimide resin varnish) onto a substrate;

(b) a step of drying the applied liquid (coating film) and then peeling it off 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, and curing the coating film to form a first hard coating layer Fair, and

(d) Process of forming a coating film by applying the curable composition (Y) to the other surface of the substrate, and then irradiating a high energy ray to the coating film, and curing the coating film to form a second hard coating layer.

It can be manufactured by a manufacturing method comprising a.

In step (a), first, a liquid (polyimide-based resin varnish) containing a polyimide-based resin is prepared. For the preparation of a 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 imidization catalyst, and Other components such as a dehydrating agent are mixed and reacted to prepare a polyimide resin mixture. As a tertiary amine, the aromatic amine, aliphatic amine, etc. mentioned above are mentioned. Examples of the dehydrating agent include acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, and isovaleric anhydride. Although reaction temperature is not specifically limited, For example, it is 50-350 degreeC. The reaction time is not particularly limited, but is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be performed under an inert atmosphere or a reduced pressure condition. Moreover, reaction may be performed in a solvent, and a solvent mentioned later used for preparation of a polyimide-type resin varnish is mentioned as a solvent, for example. A polyimide-based resin is precipitated by reprecipitation by adding a poor solvent to the polyimide-based resin mixture, and dried to extract a precipitate. If necessary, the precipitate is washed with a solvent such as methanol and dried to obtain a polyimide resin. Subsequently, a liquid (polyimide-based resin) containing a polyimide-based resin by dissolving the polyimide-based resin in a solvent and adding and stirring the inorganic particles, the ultraviolet absorber, the colorant, and other additives as necessary. Varnish). In addition, in the step (a), when silica particles are included in the polyimide resin varnish, the silica sol (solvent-dispersed silica sol) in which the silica particles are dispersed in a solvent may be mixed in the resin solution. In addition, 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 (mass%) represents the ratio (mass%) of the solid content to the mass of the resin varnish.

The solvent used for preparing the polyimide-based resin varnish is not particularly limited as long as it can dissolve the polyamide-based resin. Examples of such a solvent include amide solvents such as N, N-dimethylacetamide and N, N-dimethylformamide; lactone-based solvents such as γ-butyrolactone and γ-valerolactone; Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane; Carbonate-based solvents such as ethylene carbonate and propylene carbonate; And combinations thereof. Among these solvents, an amide solvent or a lactone solvent is preferable. Further, 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-based resin varnish is coated on a substrate such as a resin substrate, a SUS belt, or a glass substrate by a known coating method to form a coating film. As a known coating method, for example, a roll coating method such as wire bar coating method, reverse coating, gravure coating, die coating method, comma coating method, lip coating method, spin coating method, screen coating method, fountain coating method, Dipping method, spraying method, flexible molding method, and the like.

In step (b), the resin film can be formed by drying the coating film and peeling it off the substrate. After peeling, you may perform the drying process of drying a resin film further. 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 in an inert atmosphere or under reduced pressure.

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

In the steps (c) and (d), a curable composition dissolved in a solvent may be applied to the resin film. As a solvent, the thing similar to the solvent described in the term of [1st hard coating layer] is mentioned, As a coating method, the said well-known coating method is mentioned.

The coating film formed on the resin film may be dried. The coating film can be dried 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 in an inert atmosphere or under reduced pressure.

In steps (c) and (d), the coating film is irradiated with a high energy ray (eg, active energy ray), and the coating layer is cured to form a hard coating layer. The irradiation intensity is appropriately determined by the composition of the curable composition, and is not particularly limited, but irradiation of a wavelength region effective for activation of the photopolymerization initiator is preferable. The irradiation intensity is preferably 0.1 to 6,000 Pa / cm 2, more preferably 10 to 1,000 Pa / cm 2, and even more preferably 20 to 500 Pa / 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 is preferably 10 to 10,000 mJ / cm 2, more preferably 50 to 10,000 mJ / cm 2 of integrated light amount expressed as a product of the irradiation intensity and the irradiation time. It is set to be -1,000 mJ / cm2, more preferably 80-500 mJ / cm2. When the accumulated light amount is within the above range, a sufficient amount of active species derived from the photopolymerization initiator is generated, the curing reaction can proceed more reliably, and the irradiation time is not too long, so that good productivity can be maintained. Moreover, it is useful because the hardness of the hard coating layer can be further increased by going through the irradiation step in this range.

1 shows an example of the layer configuration in the optical laminate of the present invention, the present invention is not limited to this aspect. The optical layered body 1 shown in FIG. 1 has a first hard coating layer 4 laminated on one side of the resin film 2 and a second hard coating layer 3 laminated on the other side.

The optical laminate 1 of the present invention may include other layers between the resin film 2 and the first hard coating layer 4 and between the resin film 2 and the second hard coating layer 3. As another layer, a functional layer is mentioned, for example. Examples of the functional layer include a layer having various functions such as an ultraviolet absorbing layer, a primer layer, a gas barrier layer, an adhesive layer described later, a color adjusting layer, and a refractive index adjusting layer. The optical laminate of the present invention may include a singular or plural functional layers. Moreover, one functional layer may have a plurality of functions.

The ultraviolet absorbing layer is a layer having a function of absorbing ultraviolet rays, and for example, a main material selected from an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a heat curable transparent resin, and dispersed in the main material It is composed of UV absorbers.

The color adjustment layer is a layer having a function of color adjustment, and is a layer that can be adjusted to the color targeting the optical laminate. The color adjustment layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, bengala, titanium oxide-based fired pigments, ultramarine, cobalt aluminate, and carbon black; Organic pigments such as azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, styrene-based compounds, and diketopyrrolopyrrole-based compounds; Extender pigments such as barium sulfate and calcium carbonate; And dyes such as basic dyes, acid dyes, and mordant dyes.

The refractive index adjusting layer is a layer having a function of adjusting the refractive index, and is, for example, a layer having a different refractive index from the resin film and capable of imparting a predetermined refractive index to the optical laminate. The refractive index adjusting layer may be, for example, an appropriately selected resin, and optionally a resin layer containing a pigment, or a thin metal 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. By setting the average primary particle size of the pigment to 0.1 µm or less, diffuse 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 in the refractive index adjusting layer include metal oxides 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, or And metal nitrides.

In one embodiment of the present invention, the optical laminate of the present invention, the number of bending of the resin film exceeds 100,000 times, or indentation hardness measured using a nano indenter is added to 350 N / ㎟ or more Thus, since the oleic acid contact angle of the surface of the second hard coating layer is 1 ° or more and less than 65 °, it is excellent in bending resistance, and because the oleic acid contact angle of the surface of the first hard coating layer is 65 ° or more, it is on the viewing side (display side). The surface of the first hard coating layer is excellent in wipeability of contamination such as fingerprints. Therefore, even if the optical layered product of the present invention is applied to an image display device such as a flexible display, it is possible to effectively suppress changes in the color or contrast of the display portion, and to have excellent visibility.

In addition, in one embodiment of the present invention, the optical laminate of the present invention is a Charpy impact test, preferably of the shock absorbing energy 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 of 100 kJ / m 2 or more, since the oleic acid contact angle of the surface of the second hard coating layer is 1 ° or more and less than 65 °, it is excellent in bending resistance, and because the oleic acid contact angle of the surface of the first hard coating layer is 65 ° or more , Excellent in bending resistance, and since the oleic acid contact angle of the surface of the first hard coating layer is 65 ° or more, the wipeability of contamination of fingerprints and the like on the surface of the first hard coating layer on the viewing side (display side) is excellent. Therefore, even if the optical layered product of the present invention is applied to an image display device such as a flexible display, it is possible to effectively suppress changes in the color or contrast of the display portion and have excellent visibility.

In the above embodiment, in the optical laminate of the present invention, the value of the impact absorption energy is 100 kJ / m 2 or more, preferably 110 kJ / m 2 or more, more preferably 120 kJ / m 2 or more, and more preferably It is 140 kJ / m2 or more. When the value of the shock absorption energy is equal to or greater than the above lower limit, the adhesion between the hard coating layer and the resin film becomes good, and peeling during bending can be prevented. Further, the upper limit of the value of the shock absorption energy is not particularly limited, but is 1,000 kJ / m 2 or less, preferably 500 kJ / m 2 or less, more preferably 450 kJ / m 2 or less, and more preferably 400 kJ / m 2 or less. . If it is less than or equal to the above upper limit, it is easy to improve the bending resistance of the optical laminate. Here, the Charpy impact test measures the impact absorption energy of a plastic specified in JIS K 7111-1: 2006 "Plastic-Charpy impact properties-Part 1: Non-instrumented impact test". It is a trick. In addition, in this JIS, the case where a test piece with a notch is used and a case with a test piece without a notch are specified, but since the film is targeted here, a test piece without a notch is employed.

In the Charpy impact test, the impact absorption energy of the test piece is measured according to JIS K 7111-1: 2006. Specifically, for example, a test piece of about 10 mm in width and about 120 mm in length is punched or cut from a film having a thickness of 100 µm or less. Next, the test piece is fixed to both ends of the long side of the test piece so that the test piece does not move due to the impact when punching with a hammer, and the energy required to break the test piece with a Charpy impact tester (i.e., impact Absorbed energy). It means that a test piece, ie, a film, is hard to break, so that this shock absorption energy is large. Specifically, it can be measured by the method described in Examples. An optical layered product having a shock absorbing energy value of 100 kJ / m 2 or more can be produced by selecting the resin film, second hard coat, and first hard coat shown above. In addition, either the impact absorption energy measured from the side of the first hard coating layer or the impact absorption energy measured from the side of the second hard coating layer should just satisfy the above range, and both are within the above ranges from the viewpoint of bending resistance of the optical laminate. Is preferred.

The optical laminate of the present invention also has excellent surface hardness. The pencil hardness of the optical layered body is preferably HB or more, more preferably F or more, and even more preferably H or more. Note that 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 is excellent in 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 visibility is improved. In addition, the yellowness of an optical laminated body can be measured by the method described in an Example, for example.

The thickness of the optical laminate of the present invention is preferably 21 to 165 µm, more preferably 27 to 110 µm, further preferably 32 to 100 µm. When the thickness of the optical laminate is greater than or equal to the above lower limit, it is easy to improve the mechanical strength, and when it is less than or equal to the upper limit, it is easy to suppress the occurrence of cracking due to bending.

In the optical laminate of the present invention, the total light transmittance (Tt) is preferably 80% or more, more preferably 85% or more, more preferably 88% or more, even more preferably 89% or more, particularly It is preferably 90% or more. When the total light transmittance of the optical laminate is equal to or more than the above lower limit, the transparency of the optical laminate is improved, and visibility is improved. Moreover, when the total light transmittance is within the above range, it becomes possible to lower the illuminance of the backlight, for example, when the viewing side obtains the same brightness as compared with the case where the transmittance is not within the range, contributing to energy saving can do. In addition, 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 on a front panel (window film) of an image display device. Therefore, the optical laminate of the present invention can be arranged as a front plate on the viewing-side surface of an image display device, particularly a flexible display (flexible display device) or a foldable display (foldable display device). The front panel 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, an adhesive is interposed on the surface of the second hard coating layer (the side opposite to the resin film) and laminated to a polarizing plate or the like included in the image display device. It is preferred.

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 coating layer, and excellent adhesion to the pressure-sensitive adhesive, but the number of bending of the resin film exceeds 100,000 times. An image display device including an optical laminate is excellent in bending resistance. Therefore, even when the application is repeatedly performed, for example, a flexible display or a foldable display, lifting or peeling of the interface between the pressure-sensitive adhesive and the second hard coating layer or the resin film and the hard coating layer can be effectively suppressed. have. In addition, the contact angle of oleic acid on the surface of the first hard coating layer is 65 ° or more, and the wipeability of contamination such as fingerprints on the surface of the first hard coating layer is excellent. For this reason, the optical laminated body of this invention can express the outstanding visibility of the display part of an image display apparatus.

As the adhesive, one containing an acrylic polymer, a silicone polymer, a polyester, polyurethane, polyether, or the like can be used. Among them, it is preferable to use an adhesive having excellent optical transparency, maintaining an appropriate degree of wettability or cohesive force, and further having weather resistance, heat resistance, and the like, 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 it.

The acrylic pressure-sensitive adhesive composition contains a hydroxyl group such as (meth) acrylic acid alkyl ester, (meth) acrylic acid, and (meth) acrylic acid hydroxyethyl (meth) having an alkyl group having 20 or less carbon atoms such as methyl group, ethyl group, and butyl group (meth) It is preferable to include an acrylic polymer obtained by polymerizing acrylate or the like as a base polymer.

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.

Further, the weight average molecular weight of the acrylic polymer is, in terms of standard polystyrene, preferably 100,000 or more, more preferably 1,000,000 or more, and preferably 2,500,000 or less.

The acrylic pressure-sensitive adhesive composition may contain an isocyanate compound such as trimethylolpropane-modified tolylene diisocyanate as a crosslinking agent, and may include a silane compound such as 3-glycidoxypropyl trimethoxysilane as a silane coupling agent. 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 0.1 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer.

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

The acrylic pressure-sensitive adhesive layer is formed by dissolving or dispersing an acrylic pressure-sensitive adhesive composition in a solvent such as toluene or ethyl acetate to prepare a solution of 10 to 40% by mass, coating it directly on the surface of the second hard coating layer of the optical laminate, and drying it. Alternatively, the acrylic pressure-sensitive adhesive composition is coated on a substrate such as a separator in advance, and then dried to form an acrylic pressure-sensitive adhesive layer with a separator, and then the separator is peeled off and bonded to the surface of the second hard coating layer of the optical laminate. You may do it. The thickness of the pressure-sensitive adhesive layer is determined depending on the adhesive strength and the like, but about 1 to 25 μm is suitable. In addition, in this specification, a pressure-sensitive adhesive layer may be referred to simply as a pressure-sensitive adhesive.

(Flexible display device)

In the present invention, the 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 called a window film. The flexible image display device is composed of a laminate for a flexible image display device and an organic EL display panel, and a laminate for a flexible image display device is disposed on the viewer side with respect to the organic EL display panel, and is configured to be bendable. As a laminated body for a flexible image display device, a polarizing plate, preferably a circular polarizing plate, and a touch sensor may be further included, and the lamination order is arbitrary, but a window film, a polarizing plate, a touch sensor or a window film, a touch sensor from the viewer side , It is preferable that they are laminated in the order of the polarizing plate. When the polarizing plate is present on the viewing side than the touch sensor, it is preferable because the pattern of the touch sensor is difficult to visualize and the visibility of the display image is improved. Each member can be laminated using an adhesive, an adhesive, or the like. In addition, a light blocking pattern formed on at least one surface of any one of the window film, the polarizing plate, and the touch sensor may be provided.

(Circle polarizer)

As described above, the flexible display device is preferably provided with a polarizing plate, particularly a circular polarizing plate. The circular polarizing plate is a functional layer having a function of transmitting only the right or left circular polarizing component by laminating a λ / 4 phase difference plate on the linear polarizing plate. For example, by converting external light into right circularly polarized light, it is reflected by the organic EL panel, blocks external light that is left circularly polarized, and transmits only the light emitting component of the organic EL to suppress the influence of reflected light and make it easier to see images do. In order to achieve the circular polarization function, the absorption axis of the linear polarizing plate and the slow axis of the λ / 4 retardation plate need to be theoretically 45 °, but practically 45 ± 10 °. The linear polarizing plate and the λ / 4 retardation plate do not necessarily need to be stacked adjacent to each other, and the relationship between the absorption axis and the slow axis should just satisfy the above range. It is desirable to achieve full circular polarization at all wavelengths, but in practical use, it is not necessary, so the circular polarizing plate in the present invention also includes an elliptical polarizing plate. It is also preferable to further improve the visibility in a state in which polarized sunglass is worn by further laminating a λ / 4 phase difference film on the viewing side of the linear polarizing plate and making the emitted light circularly polarized.

The linearly polarizing plate is a functional layer having a function of passing through light oscillating in the direction of the transmission axis, but blocking polarization of a vibration component perpendicular to it. The linear polarizer may be configured with a linear polarizer alone or a linear polarizer and a protective film attached to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, and is preferably 0.5 to 100 μm. When the thickness of the linear polarizing plate is within the above range, the flexibility of the linear polarizing plate tends to be difficult to deteriorate.

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

Moreover, as another example of the said polarizer, the liquid crystal coating type polarizer formed by apply | coating a liquid crystal polarizing composition is mentioned. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The above-mentioned liquid crystalline compound only needs to have a property exhibiting a liquid crystal state, and in particular, it is preferable because it can exhibit high polarization performance if it has a high-order alignment state such as a smectic phase. Moreover, it is preferable that a liquid crystal compound has a polymerizable functional group.

The dichroic dye compound may be aligned with the liquid crystal compound to exhibit dichroism and may have a polymerizable functional group, or the dichroic dye itself may have liquid crystallinity.

Any of the compounds included 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, and a silane coupling agent.

The said liquid crystal polarizing layer is manufactured by apply | coating a liquid crystal polarizing composition on an alignment film, and forming a liquid crystal polarizing layer. The liquid crystal polarizing layer can be formed to have a thinner thickness than the film-type polarizer, and the thickness is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.

The said alignment film is manufactured, for example by apply | coating the alignment film formation composition on a base material, and providing orientation by rubbing, polarization irradiation, etc. The alignment film forming composition may include an alignment agent, and may further include a solvent, a crosslinking agent, an initiator, a dispersing agent, a leveling agent, a silane coupling agent, and the like. Examples of the alignment agent include polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides. When using the alignment agent which provides orientation by polarization irradiation, it is preferable to use the alignment 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 film thickness of the alignment film is preferably 5 to 10,000 nm, and more preferably 10 to 500 nm in that the orientation regulating force is sufficiently expressed.

The liquid crystal polarizing layer may be peeled off from the substrate and transferred and laminated, or the substrate may be laminated as it is. It is also preferable that the substrate serves as a transparent substrate for the protective film, retardation plate, and window film.

As the protective film, a transparent polymer film may be used, and the same material or additive used for the transparent substrate of the window film can be used. Moreover, the coating type protective film obtained by apply | coating and curing a cationic curing composition, such as an epoxy resin, or a radical curing composition, such as an acrylate, may be sufficient. The protective film may contain a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent, and the like, if necessary. . The thickness of the protective film is preferably 200 μm or less, and more preferably 1 to 100 μm. When the thickness of the protective film is within the above range, the flexibility of the film tends to be difficult to deteriorate.

The λ / 4 retardation plate is a film that provides a retardation of λ / 4 in a direction orthogonal to the traveling direction of incident light (in-plane direction of the film). The λ / 4 retardation plate may be a stretched retardation plate produced by stretching a polymer film such as a cellulose-based film, an olefin-based film, or a polycarbonate-based film. The λ / 4 retardation plate is a retardation regulator, a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or dye, a fluorescent whitening agent, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, and a solvent, if necessary. Etc. may be included.

The thickness of the stretched retardation plate is preferably 200 μm or less, and more preferably 1 to 100 μm. When the thickness of the stretched retardation plate is within the above range, the flexibility of the stretched retardation plate tends to be less likely to decrease.

Moreover, as another example of the lambda / 4 phase difference plate, a liquid crystal coating type retardation plate formed by applying a liquid crystal composition is mentioned.

The liquid crystal composition includes a liquid crystal compound exhibiting liquid crystal states such as nematic, cholesteric, and smectic. The liquid crystal 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, and a silane coupling agent.

The liquid crystal coating-type retardation plate can be produced by coating and curing a liquid crystal composition on a base, as in the liquid crystal polarizing layer, to form a liquid crystal retardation layer. The liquid crystal-coated retardation plate can be formed to have a thinner thickness than the stretched retardation plate. The thickness of the liquid crystal polarizing layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.

The liquid crystal coating type retardation plate may be peeled off from the substrate and transferred to be laminated, or the substrate may be laminated as it is. It is also preferable that the substrate serves as a transparent substrate for the protective film, retardation plate, and window film.

In general, the shorter the wavelength, the greater the birefringence and the longer the wavelength, the more materials exhibiting the smaller birefringence. In this case, since a phase difference of λ / 4 cannot be achieved in the entire visible light region, the in-plane phase difference is preferably 100 to 180 nm, more preferably 130, so that it becomes λ / 4 with respect to the vicinity of 560 nm with high visibility. It is designed to be -150 nm. The reverse dispersion λ / 4 retardation plate using a material having a birefringence wavelength dispersion characteristic as opposed to normal is preferable in view of good visibility. As such a material, for example, a stretched retardation plate described in JP 2007-232873 A and the like and a liquid crystal coated retardation plate described in JP 2010-30979 A 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. Hei 10-90521, etc.). The λ / 2 retardation plate is also made of the same material and method as the λ / 4 retardation plate. The combination of the stretched retardation plate and the liquid crystal coating retardation plate is arbitrary, but the thickness of the film can be reduced by using either of the liquid crystal coating retardation plates.

In order to increase visibility in an oblique direction, a method of laminating a positive C plate is known to the original polarizing plate (for example, Japanese Patent Application Laid-open No. 2014-224837, etc.). The definition C plate may be a liquid crystal coating type retardation plate or a stretched retardation plate. The phase difference in the thickness direction of the phase difference plate is preferably -200 to -20 nm, more preferably -140 to -40 nm.

〔Touch sensor〕

The flexible display device is preferably provided with a touch sensor as described above. The touch sensor is used as an input means. As a touch sensor, various forms, such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitive method, are mentioned, Preferably, a capacitive method is mentioned.

The capacitive touch sensor is divided into an active area and an inactive area located on an outer portion of the active area. The active area is an area corresponding to an area (display area) where a screen is displayed on the display panel, and an area where a user's touch is detected, and an inactive area is an area corresponding to an area (non-display area) where a screen is not displayed on the display device. . The touch sensor has a flexible substrate, a sensing pattern formed in an active region of the substrate, and a sensing pattern formed in an inactive region of the substrate, and connected to an external driving circuit via the sensing pattern and a pad portion. It may include. As the substrate having flexible properties, a material similar to that of the transparent substrate of the window film can be used.

The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and in order to sense a touched point, each pattern must be electrically connected. The first pattern is a form in which a plurality of unit patterns are connected to each other via a seam, but the second pattern is a structure in which a plurality of unit patterns are separated from each other in an island form, and thus, to electrically connect the second pattern, separate Bridge electrodes are required. A well-known transparent electrode can be applied to the electrode for connection of the 2nd pattern. As a 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 nanotubes (CNT), graphene, metal wires, and the like, and preferably ITO. These may be used alone or in combination of two or more. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium. These may be used alone or in combination of two or more. .

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

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

The touch sensor has a difference in transmittance between a pattern area where a sensing pattern is formed and a non-pattern area where no sensing pattern is formed, specifically, a light transmittance caused by a difference in the refractive index in these areas. As a means for properly compensating for the difference, an optical control layer may be further included between the substrate and the electrode. The optical control layer may include an inorganic insulating material or an organic insulating material. The optical control layer may be formed by coating a photocurable composition comprising a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The refractive index of the optical control layer can be increased by the inorganic particles.

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

As said inorganic particle, zirconia particle, titania particle, alumina particle, etc. are mentioned, for example.

The photocurable composition may further include each additive such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

〔Adhesive layer〕

Each layer (window film, circular polarizing plate, touch sensor) forming the laminate for the flexible image display device and the film member (linear polarizing plate, λ / 4 retardation plate, etc.) constituting each layer can be bonded by an adhesive. . Examples of the adhesive include water-based adhesives, organic solvent-based, solvent-free adhesives, solid adhesives, solvent volatilization-type adhesives, moisture-curable adhesives, heat-curable adhesives, anaerobic curing type, active energy ray-curable adhesives, curing agent mixed adhesives, heat-melting adhesives, and pressure-sensitive adhesives Adhesives (adhesives), rewet type adhesives, and other commonly used adhesives can be used, and preferably an aqueous solvent volatilization type adhesive, active energy ray-curable adhesive, or adhesive can be used. The thickness of the adhesive layer can be appropriately adjusted depending on the required adhesive strength, etc., preferably 0.01 to 500 µm, more preferably 0.1 to 300 µm. Although a plurality of adhesive layers exist in the laminate for the flexible image display device, the thickness and type of each may be the same or different.

As the aqueous solvent-based adhesive, a water-dispersible polymer such as a polyvinyl alcohol-based polymer, a water-soluble polymer such as starch, an ethylene-vinyl acetate-based emulsion, or a styrene-butadiene-based emulsion can be used as the 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, etc. may be blended. In the case of bonding with the water-based solvent volatilization-type adhesive, the water-based solvent volatilization-type adhesive is injected between the adhered layers to bond the adhered layers, followed by drying to impart adhesion. When the above-mentioned water-based solvent volatilization type 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 above-mentioned water-based solvent volatilization type adhesive is used for a plurality of layers, the thickness or type of each layer may be the same or different.

The active energy ray-curable adhesive may be formed by curing an active energy ray-curing composition containing a reactive material that irradiates active energy rays to form an adhesive layer. The active energy ray-curable composition may contain at least one polymerizable product of a radically polymerizable compound and a cationic polymerizable compound similar to those contained in the hard coating composition. As the radically polymerizable compound, the same compound as the radically polymerizable compound in the hard coating composition can be used.

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

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

The active energy ray curing composition may contain a monofunctional compound in order to lower the viscosity. As the monofunctional compound, an acrylate-based monomer having one (meth) acryloyl group in one molecule or a compound having one epoxy group or oxetanyl group in one molecule, for example, glycidyl (meth) And acrylates.

The active energy ray curing composition may 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 suitably selected and used. These polymerization initiators are decomposed by at least one kind of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cation polymerization. Among the substrates of the hard coating composition, an initiator capable of initiating at least either radical polymerization or cationic polymerization by active energy ray irradiation may be used.

The active energy ray curing composition may also include an ion trapping agent, antioxidant, chain transfer agent, adhesion agent, thermoplastic resin, filler, flow viscosity modifier, plasticizer, antifoaming agent, additive, and solvent. In the case of bonding two to-be-adhesive layers by the active energy ray-curable adhesive, the active energy ray-curable composition is applied to one or both of the to-be-adhesive layers, and then bonded to the active energy ray to either or both of the to-be-adhesive layers. It can be adhered by irradiating and curing. 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 or type of each layer may be the same or different.

As the pressure-sensitive adhesive, the same pressure-sensitive adhesive as described above can be used. When using multiple layers of the said adhesive, the thickness and kind of each layer may be same or different.

(Shading pattern)

The light-shielding pattern can be applied as at least a part of the bezel or housing of the flexible image display device. The visibility of the image is improved by shielding the wiring arranged in the edge portion of the flexible image display device by the light-shielding pattern, making it difficult to visually recognize it. 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 various colors such as black, white, and metal may be used. The light-shielding pattern may be formed of a pigment for realizing color, and a polymer such as acrylic resin, ester resin, epoxy resin, polyurethane, and silicone. These may be used alone or in combination 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. Moreover, it is also preferable to give a shape, such as a slope, in the thickness direction of a light-shielding pattern.

[Example]

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 Examples and Comparative Examples was measured using a Micrometer (Mitutoyo), and the thicknesses of the first hard coating layer and the second hard coating layer were measured by an F20 desktop film thickness system manufactured by Filmetrics.

(2) Measurement of flex resistance

According to ASTM standard D2176-16, the number of times of bending of the resin film in an Example and a comparative example was calculated as follows. The resin film was cut into a rectangular shape having a long length of 15 mm × 100 mm using a dumbbell cutter. The cut resin film was set on the MIT internal fatigue tester ("Type 0530", manufactured by Toyo Seiki Co., Ltd.), the test speed was 175 cpm, the bending angle was 135 °, the load was 0.75 kgf, and the bending radius of the bending clamp was R = Under the condition of 3 mm, the number of reciprocating bending in the front and back direction until the resin film was broken was measured, and this was called the number of bending.

(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 under the following conditions using a nanoindentation tester (Erionix Co., Ltd., ENT-2100). The measurement position was taken as the central portion of the resin film plane, and the average value of five points close to the center of the thickness direction of the central portion was referred to as indentation hardness (N / mm 2).

Abkhazia: Berkovich Abkhazia

Surface detection: Load (0.6 mgf)

Load curve: 0.6 mN (linear) over 10 seconds

Cliff: 0.6 mN for 10 seconds

Subtraction curve: 0 mN over 10 seconds (linear)

(4) Measurement of oleic acid contact angle

According to JIS R3257, the contact angle of oleic acid 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 shock absorption energy of the optical laminates of Examples and Comparative Examples was determined. From the optical laminates of Examples and Comparative Examples, a rectangular test piece having a width of 10 mm and a length of 120 mm was cut out. To prevent the specimen from moving due to the impact of punching with a hammer, fix both ends of the specimen in the long side direction to the support, and by the Charpy Impact Tester manufactured by Yasuda Seiki Co., Ltd., the length of the end of the blade was measured. In order to be parallel to the thickness direction in the central portion in the long axis direction, the first hard coating layer side of the optical layered body was collided to measure the energy required to break the film (that is, the energy absorbed by impact). In addition, the side to hit the hammer was also carried out on the second hard coating layer side, instead of the first hard coating layer side.

(6) Evaluation of visibility

(Preparation of visibility evaluation sample)

In a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dripping device and a nitrogen introduction tube, 97.0 parts by mass of n-butyl acrylate, 1.0 parts by mass of acrylic acid, 0.5 parts by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile was introduced, and air in the reaction vessel was replaced with nitrogen gas. While stirring under a nitrogen atmosphere, the reaction solution was heated to 60 ° C, 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, the production of 1.8 million (meth) acrylic acid ester polymers was confirmed.

100 parts by mass of the (meth) acrylic acid ester polymer (solid content conversion value; hereinafter the same) and 0.30 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, trade name `` Colonate L '') as an isocyanate-based crosslinking agent , As a silane coupling agent, 0.30 parts by mass of 3-glycidoxypropyl trimethoxysilane (trade name "KBM403" manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was mixed and stirred sufficiently to obtain an adhesive composition. Next, a coating solution of the pressure-sensitive adhesive composition was obtained by diluting the pressure-sensitive adhesive composition with ethyl acetate.

On the release treatment surface (release layer surface) of the separator (manufactured by Lintec Co., Ltd .: SP-PLR382190), the coating solution was coated with an applicator so that the thickness after drying was 25 μm, followed by drying at 100 ° C. for 1 minute. An adhesive layer was obtained. Subsequently, one more separator (manufactured by Lintec Co., Ltd .: SP-PLR381031) was bonded to the surface opposite to the surface to which the separator of the pressure-sensitive adhesive layer was pasted to obtain a pressure-sensitive adhesive layer with a double-sided separator.

After peeling the separator from the pressure-sensitive adhesive layer provided with the double-sided separator, the pressure-sensitive adhesive layer was adhered to the surface of the second hard coating layer of the optical laminate, and the PET film on the side of the pressure-sensitive adhesive layer opposite to the side on which the optical laminate was glued (see ), Product name: Cosmo Shine (registered trademark) A4100) was pasted to obtain a laminate having an optical laminate / adhesive / PET film in this order.

(Evaluation of visibility)

The laminate (sample for measurement of visibility) having the optical laminate / adhesive / PET film in this order was cut into a rectangular shape having a length of 15 mm × 100 mm using a dumbbell cutter. The cut laminate was set on the MIT internal fatigue tester ("Type 0530", manufactured by Toyo Seiki Co., Ltd.), and the test speed was 175 cpm, bending angle 135 °, load 0.75 kgf, bending radius of bending clamp R Under the condition of = 3 mm, 1000 times of bending in the front and rear directions (the number of bending times) were performed. On the surface of the first hard-coated layer of the optical laminate after bending, three testers touched the finger 10 times each with a finger to smear the fingerprint, and the fingerprint was wiped 4 times with a BEMCOT. Thereafter, under the fluorescent lamp, the state of appearance changes such as discoloration or whitening due to peeling of the adhesive or peeling of the adhesive was confirmed from the surface side of the first hard coating layer, and visibility was determined by the following criteria.

(Evaluation standard)

A… Fingerprint remaining, and no change in appearance such as discoloration or whitening was observed.

B… Fingerprints remained, and changes in appearance such as discoloration and whitening were slightly confirmed.

C… Remaining fingerprints and changes in appearance such as discoloration or whitening were clearly identified.

(7) Measurement of pencil hardness

In accordance with JIS K5600-5-4: 1999, the pencil hardness of the surface of the first hard coat layer of the optical laminate obtained in Examples and Comparative Examples was measured using Mitsubishi Pencil Co., Ltd. Uni. More specifically, the optical layered product was fixed on a glass plate having a thickness of 2 mm, measured under conditions of an angle of 90 °, a load of 750 g, and a scanning speed of 60 mm / min. Was evaluated to determine the pencil hardness.

(8) Measurement of yellowness (YI value)

By using the spectrophotometer (U-4100) manufactured by Hitachi Manufacturing Co., Ltd., the three stimulus values X, Y and Z calculated by the calculation method specified in JIS Z 8701: 1982, and The yellowness (YI value) of the optical laminate obtained in the comparative example was calculated.

YI = 100 (1.28X-1.06Z) / Y

(9) Measurement of total light transmittance (Tt)

The total light transmittance Tt of the optical laminate obtained in Examples and Comparative Examples was measured by a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Tester Co., Ltd. in accordance with JIS K 7105: 1981.

(10) Measurement of weight average molecular weight (Mw)

The weight average molecular weights (Mw) of the polyimide and polyamideimide of the examples and comparative examples were determined by gel permeation chromatography (GPC) measurement, by standard polystyrene conversion. The specific measurement conditions are as follows.

(i) Pretreatment method

A solution obtained by adding DMF eluent (10 mM lithium bromide solution) to a concentration of 2 mg / mL to the polyimide of Examples and Comparative Examples to a concentration of 2 mg / mL, heating with stirring at 80 ° C. for 30 minutes, cooling, and filtering with a 0.45 μm membrane filter Was used as the measurement solution.

(ii) Measurement conditions

Column: TSKgel SuperAWM-H × 2 + SuperAW2500 × 1 (6.0 mm I.D. × 150 mm × 3 pcs.)

Eluent: DMF (10 mM lithium bromide added)

Flow rate: 1.0 mL / min.

Detector: RI detector

Column temperature: 40 ℃

Injection volume: 100 μL

Molecular weight standard: standard polystyrene

2. Preparation of resin film

(1) Resin film A

Polyimide having a polyimide concentration of 12% by mass by dissolving polyimide (Kawamura Industries Co., Ltd. "KPI-MX300F (100)", fluorine atom-containing polyimide, weight average molecular weight 300,000) in γ-butyrolactone. A solution was obtained. The obtained polyimide solution was applied to a glass substrate, and the solvent was removed by heating at 50 ° C for 30 minutes and at 140 ° C for 10 minutes. Thereafter, the polyimide film was peeled from the glass substrate, and a metal frame was mounted and heated at 200 ° C. for 30 minutes to obtain a 80 µm thick transparent resin film.

(2) Resin film B

Polyimide having a polyimide concentration of 16% by mass by dissolving polyimide (Kawamura Industries Co., Ltd. "KPI-MX300F (100)", fluorine atom-containing polyimide, and weight average molecular weight of 300,000) in γ-butyrolactone. A solution was prepared, and a solution in which silica particles (average primary particle size: 22 nm) having a solid content concentration of 30 mass% was dispersed in γ-butyrolactone was mixed with the polyimide solution, and stirred for 30 minutes. The mass ratio of silica particles and polyimide was 40:60. The polyimide solution containing silica particles was applied to a glass substrate, and heated at 50 ° C for 30 minutes and 140 ° C for 10 minutes to remove the solvent. Thereafter, the polyimide film was peeled from the glass substrate, and a metal frame was mounted and heated 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, to a 1 L separable flask equipped with a stirring blade, 40 g (124.91 mmol) of TFMB and 682.51 g of DMAc were added, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 6FDA 16.78 g (37.77 mmol) was added to the flask and stirred at room temperature for 3 hours. Thereafter, 3.72 g (12.59 mmol) of OBBC, and then 15.34 g (75.55 mmol) of TPC were added to the flask and stirred at room temperature for 1 hour. Subsequently, 8.21 g (88.14 mmol) of 4-methylpyridine and 15.43 g (151.10 mmol) of acetic anhydride were added to the flask, stirred at room temperature for 30 minutes, heated to 70 ° C using an oil bath, and further stirred for 3 hours. By doing, a reaction solution was obtained.

The obtained reaction solution was cooled to room temperature, charged into a large amount of methanol in a thread shape, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain a polyamideimide. The polyamideimide had a weight average molecular weight (Mw) of 400,000.

Substitution of methanol-dispersed surface-modified silica sol having a BET diameter (average particle diameter measured by the BET method) of 27 nm (silica sol obtained by dispersing surface-modified silica particles in methanol) with γ-butyrolactone (GBL) Then, GBL dispersion organic treatment silica sol (solid content concentration: 30%) was obtained. To replace the solvent, γ-butyrolactone (GBL) is added to the silica sol dispersed on the surface of methanol dispersion, and it is 1 hour at 400 hPa and 1 hour at 250 hPa under a 45 ° C bath with a vacuum evaporator. It was carried out by evaporating methanol and heating up to 70 ° C under 250 hPa for 30 minutes.

At room temperature, in the GBL solvent, the obtained polyamideimide and the GBL dispersion organic treatment silica sol were mixed so that the composition ratio of the resin and the silica particles was 60:40, and thereto Sumisorb 340 (manufactured by Sumika Chemtex Co., Ltd.) and Sumiplast Violet B (manufactured by Sumika Chemtex Co., Ltd.) was added to 5.7% by mass and 35 ppm, respectively, based on the total mass of the polyamideimide and the silica particles, and stirred until uniform. A polyamideimide varnish having a solid content concentration of 10% by mass was obtained.

After filtering the obtained polyamide-imide varnish with a filter having a pore size of 10 μm, an applicator was used so that the film thickness of the freestanding film was 55 μm on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name “A4100”). And then dried at 50 ° C for 30 minutes and then at 140 ° C for 15 minutes, the obtained coating film was peeled off from the polyester substrate to obtain a freestanding film. The freestanding film was fixed to a metal frame, and further dried under air at 40 ° C. for 40 minutes to obtain a transparent resin film having a thickness of 50 μm.

(4) Resin film D

Under a nitrogen gas atmosphere, to a 1 L separable flask equipped with a stirring vane, TFMB 53.05 g (165.66 mmol) and DMAc 670.91 g were added, and TFMB was dissolved in DMAc while stirring at room temperature. Next, to the flask, 6FDA 22.11 g (49.77 mmol), 3,3 ', 4,4'-biphenyltetracarboxylic acid anhydride (BPDA) 4.88 g (16.59 mmol) was added, followed by TPC 20.21 g ( 99.54 mmol) was added and stirred at room temperature for 1 hour. Subsequently, 10.53 g (133.08 mmol) of pyridine and 13.77 g (134.83 mmol) of acetic anhydride were added to the flask, stirred at room temperature for 30 minutes, heated to 70 ° C using an oil bath, and stirred for an additional 3 hours to react. Liquid was obtained.

The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in a thread shape, and the precipitate precipitated was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain polyamideimide. The polyamideimide had a weight average molecular weight (Mw) of 190,000.

The composition ratio of the resin and silica particles was 70:30, and Sumisorb 340 (manufactured by Sumika Chemtex Co., Ltd.) and Sumiplast Violet B (manufactured by Sumika Chemtex Co.) were not added. By the method, a polyamideimide varnish having a solid content concentration of 10% by mass was obtained, and a transparent resin film having a thickness of 50 µm was obtained.

(5) Resin film E

Under a nitrogen gas atmosphere, to a 1 L separable flask equipped with a stirring vane, 53.05 g (165.66 mmol) of TFMB and 669.70 g of DMAc were added, 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 stirred at room temperature for 1 hour. Subsequently, 10.51 g (132.84 mmol) of pyridine and 13.74 g (134.59 mmol) of acetic anhydride were added to the flask, stirred at room temperature for 30 minutes, heated to 70 ° C using an oil bath, and stirred for an additional 1 hour to react. Liquid was obtained.

The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in a thread shape, and the precipitate precipitated was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain a polyamideimide. The polyamideimide had a weight average molecular weight (Mw) of 197,000.

A polyamideimide varnish having a solid content concentration of 10% by mass was obtained in the same manner as in the resin film D, except that the composition ratio of the resin and the silica particles was 95: 5, to obtain a transparent resin film having a thickness of 50 µm.

3. Preparation 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 0.3 parts by mass of polymer type fluorine-based surfactant as a fluorine-containing compound (Bicke Japan Co., Ltd., `` BYK-340 '',) And fluorine-based water and oil repellent (Neos Co., Ltd., "Ptergent" (registered trademark) 601ADH2 ") 0.6 parts by mass, as a photopolymerization initiator 1.9 parts by mass (BASF Japan Corporation," IRGACURE (registered trademark) 184 ", 1 -Hydroxycyclohexylphenylketone) and 35.5 parts by mass of propylene glycol monomethyl ether as a solvent were mixed 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, polysiloxane compounds (Bicke Japan Co., Ltd., "BYK-307", polyether-modified dimethylsiloxane), photopolymerization Curable composition B was prepared by mixing 2.0 parts by mass as an initiator ("IRGACURE 184" manufactured by BASF Japan Co., Ltd.) and 32.7 parts by mass of propylene glycol monomethyl ether as a solvent.

(3) Curable composition C

As a curable compound, 32.5 parts by mass of pentaerythritol tetraacrylate and 32.5 parts by mass of trimethylolpropane triacrylate, poly (meth) acrylate compound as a surface modifier (Bicke Japan Co., Ltd., `` BYK-350 '', acrylic copolymer ), 1.9 parts by mass as a photopolymerization initiator (BASF Japan Co., Ltd., "IRGACURE 184"), and 32.5 parts by mass of propylene glycol monomethyl ether (PGM) as a solvent were mixed to prepare a curable composition C.

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

4. Preparation of optical laminate

(Example 1)

Using a resin film A having a film thickness of 80 µm, a curable composition A was applied to one side by a bar coater, dried at 80 ° C. for 3 minutes, and then under a nitrogen atmosphere using a high pressure mercury lamp, 500 mJ / cm 2 , By irradiating and curing under conditions of 200 Pa / cm 2, a first hard coating layer (HC1) was formed. The curable composition C was applied to the other side 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 500 mJ / cm 2 and 200 kPa / cm 2 conditions. By irradiating and curing, a second hard coating layer was formed to obtain an optical laminate. The film thickness of the first hard coating layer and the second hard coating layer (HC2) was 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 76 °, and the oleic acid contact angle of the second hard coating layer surface was 10 °. The pencil hardness of the optical laminate was H.

(Example 2)

Using a resin film A having a film thickness of 80 µm, a curable composition A was applied to one side by a bar coater, dried at 80 ° C. for 3 minutes, and then under a nitrogen atmosphere using a high pressure mercury lamp, 500 mJ / cm 2 , By irradiating and curing under conditions of 200 Pa / cm 2, a first hard coating layer was formed. The curable composition B was applied to the other side 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 500 mJ / cm 2 and 200 mm 2 / cm 2 conditions. By irradiating and curing, a second hard coating layer was formed to obtain an optical laminate. The film thickness of the first hard coating layer and the second hard coating layer was 8 μm, respectively. The oleic acid contact angle of the first hard coat layer surface was 76 °, and the oleic acid contact angle of the second hard coat layer surface was 46 °. The pencil hardness of the optical laminate was 3H.

(Example 3)

Using a resin film B having a film thickness of 50 µm, the curable composition A was applied to one side by a bar coater, dried at 80 ° C. for 3 minutes, and then under a nitrogen atmosphere using a high pressure mercury lamp, 500 mJ / cm 2 , By irradiating and curing under conditions of 200 Pa / cm 2, a first hard coating layer was formed. The curable composition C was applied to the other side 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 500 mJ / cm 2 and 200 kPa / cm 2 conditions. By irradiating and curing, a second hard coating layer was formed to obtain an optical laminate. The film thickness of the first hard coating layer and the second hard coating layer was 8 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 76 °, and the oleic acid contact angle of the second hard coating layer surface 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 a resin film C having a film thickness of 50 µm was used. The film thickness of the first hard coating layer and the second hard coating layer was 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 76 °, and the oleic acid contact angle of the second hard coating layer surface 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 film thickness of 50 µm was used. The film thickness of the first hard coating layer and the second hard coating layer was 8 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 76 °, and the oleic acid contact angle of the second hard coating layer surface was 10 °. The pencil hardness of the optical laminate was 3H.

(Example 6)

An optical laminate was obtained in the same manner as in Example 4, except that the resin film D having a film thickness of 50 µm was used. The film thickness of the first hard coating layer and the second hard coating layer is 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface is 76 °, and the oleic acid contact angle of the second hard coating layer surface is 10 °.

(Example 7)

An optical laminate was obtained in the same manner as in Example 4, except that the resin film E having a film thickness of 50 µm was used. The film thickness of the first hard coating layer and the second hard coating layer is 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface is 76 °, and the oleic acid contact angle of the second hard coating layer surface is 10 °.

(Comparative Example 1)

Using a resin film A having a film thickness of 80 µm, a curable composition A was applied to one side by a bar coater, dried at 80 ° C. for 3 minutes, and then under a nitrogen atmosphere using a high pressure mercury lamp, 500 mJ / cm 2 , By irradiating and curing under conditions of 200 Pa / cm 2, a first hard coating layer was formed. The curable composition A was applied to the other side of the resin film A with a bar coater, dried at 80 ° C. for 3 minutes, and then under nitrogen atmosphere using a high pressure mercury lamp under 500 mJ / cm 2 and 200 kPa / cm 2 conditions. By irradiating and curing, a second hard coating layer was formed to obtain an optical laminate. The film thickness of the first hard coating layer and the second hard coating layer was 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 76 °, and the oleic acid contact angle of the second hard coating layer surface was 76 °. The pencil hardness of the optical laminate was H.

(Comparative Example 2)

The optical layered product was obtained like Comparative Example 1 except having used curable composition C instead of curable composition A. The film thickness of the first hard coating layer and the second hard coating layer was 3 μm, respectively. The oleic acid contact angle of the first hard coating layer surface was 10 °, and the oleic acid contact angle of the second hard coating layer surface was 10 °. The pencil hardness of the optical laminate was H.

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

All of the optical laminates obtained in Examples 1 to 5 had A or B as a result of the visibility evaluation. That is, the optical laminates obtained in Examples 1 to 5 are excellent in wipeability and bending resistance of fingerprints and can exhibit excellent visibility even after the MIT fracture fatigue test, that is, after bending is repeated 1,000 times. On the other hand, all of the optical laminates obtained in Comparative Example 1 in which the oleic acid contact angle of the surface of the second hard coating layer was outside the range of 1 ° or more and less than 65 °, and Comparative Example 2 in which the oleic acid contact angle of the surface of the first hard coating layer was less than 65 ° were all the above visibility The result of the evaluation is C, and visibility is poor.

About the optical laminate obtained in Examples 6 and 7, the result of the above-mentioned visibility evaluation was A or B, and the wipeability and bending resistance of the fingerprint were excellent, and excellent visibility was exhibited.

In addition, the optical laminates obtained in Examples 1 to 5 were excellent in transparency, since the pencil hardness was H or 3H, and the surface hardness was excellent and the yellowness was 1.5 or 1.6 and the total light transmittance was 92%. .

One … Optical laminate
2 … Resin film
3… 2nd hard coating layer
4 … 1st hard coating layer

Claims (12)

A resin film comprising a polyimide-based resin, an optical laminate having a first hard coating layer laminated on one side of the resin film and a second hard coating layer laminated on the other side, wherein the resin film is ASTM In the MIT internal fatigue test with a bending radius of 3 mm according to the standard D2176-16, the number of bending times exceeds 100,000 times, the first hard coating layer has an oleic acid contact angle of 65 ° or more, and the second hard coating layer has an oleic acid contact angle of 1 ° or more and less than 65 °, the optical laminate. A resin film comprising a polyimide-based resin, an optical laminate having a first hard coating layer laminated on one side of the resin film and a second hard coating layer laminated on the other side, wherein the resin film has a thickness The indentation hardness measured using a nano indenter in a cross section in the direction is 350 N / mm 2 or more, the first hard coating layer has an oleic acid contact angle of 65 ° or more, and the second hard coating layer has an oleic acid contact angle of 1 ° to less than 65 °. , Optical laminate. An optical laminate having a resin film comprising a polyimide-based resin, a first hard coating layer laminated on one side of the resin film, and a second hard coating layer laminated on the other side, wherein the first hard coating layer is The optical laminate according to the present invention, wherein the oleic acid contact angle is 65 ° or more, and the second hard coating layer has an oleic acid contact angle of 1 ° or more and less than 65 °, and a value of shock absorption energy by a Charpy impact test is 100 kJ / m 2 or more. The method according to any one of claims 1 to 3,
The polyimide-based resin has an optical laminate having a weight average molecular weight of 50,000 to 1,000,000 in terms of polystyrene. The method according to any one of claims 1 to 3,
The polyimide-based resin contains an fluorine atom, an optical laminate. The method according to any one of claims 1 to 3,
The thickness of the resin film is 20 ~ 150 ㎛, optical laminate. The method according to any one of claims 1 to 3,
The first hard coating layer is a cured product of a curable composition containing a fluorine-containing compound, an optical laminate. The method of claim 7,
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 method according to any one of claims 1 to 3,
The thickness of the 1st hard coating layer and the thickness of the 2nd hard coating layer are 1-15 micrometers, respectively. The method according to any one of claims 1 to 3,
The ratio of the thickness of the 1st hard coating layer and the thickness of the 2nd hard coating layer is 10: 7-7: 10, The optical laminated body. The method according to any one of claims 1 to 3,
The optical layered body whose yellowness is 5.0 or less. The method according to any one of claims 1 to 3,
The optical laminate having a total light transmittance of 80% or more.

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