TW202302718A - Optical laminate and flexible display device - Google Patents

Abstract

An object of the present invention is to provide an optical laminate whose surface does not dent from contact with an external factor. The solution of the present invention to the above object is an optical laminate which includes a substrate layer made of a polyimide-based resin film and a functional layer containing a cured product of a curable resin, and has a yield stress of 100 MPa or more at a tensile speed of 100 mm/min.

Description

Optical laminate and flexible display device

The present invention relates to an optical laminate comprising a substrate layer made of a polyimide resin film, a functional layer comprising a cured product of a curable resin, and a flexible display provided with the optical laminate device.

Conventionally, glass has been used for front panels of display members such as solar cells and image display devices.

However, glass does not have characteristics sufficient to meet recent demands for miniaturization, thinning, weight reduction, and flexibility, and various films are being considered as substitute materials for glass. Such a film includes, for example, a polyimide-based resin film (for example, JP-A-2008-12675, JP-A-2020-64236, WO2014/046180, etc.).

In flexible electronic devices such as flexible display devices, the surface of the polyimide resin film used as the front panel may be in contact with external factors such as a stylus, so the requirements for the front panel system are not easy to be affected by external factors. Depression occurs on the surface due to contact with factors, and the recovery of the concave surface, etc. However, conventional optical films or optical laminates are not sufficiently resistant to such a dishing phenomenon. Therefore, the object of the present invention is to provide an optical layered body that does not easily cause depressions on the surface due to contact with external factors.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and found that the above-mentioned problems can be solved by an optical layered body, thereby completing the present invention. The optical layered system includes a substrate layer made of a polyimide-based resin film, and a functional layer comprising a cured product of a curable resin, and satisfying specific physical property values.

That is, the present invention includes the following aspects.

[1] An optical laminate comprising a substrate layer made of a polyimide resin film and a functional layer comprising a cured product of a curable resin, and the tensile speed of the optical laminate is 100mm/ The yield stress in minutes is 100 MPa or more.

[2] The optical laminate according to [1], wherein the polyimide-based resin film has a yield stress of 200 MPa or more at a stretching speed of 0.1 m/sec.

[3] The optical layered product according to [1] or [2], which has a thickness of 15 to 120 μm and a bending resistance of 200,000 or more as measured at R=1.5 mm.

[4] The optical laminate according to any one of [1] to [3], wherein a jig having a compressive modulus of elasticity of 3.0 GPa and a tip with a diameter of 0.7 mm is used And the depth of permanent depression when measured with a load of 200g is 0.5μm or less.

[5] The optical laminate according to any one of [1] to [3], wherein the permanent property when measured under a load of 1000 g is used using an auxiliary device having a compressive modulus of elasticity of 1.0 GPa and a tip having a diameter of 0.7 mm. The depression depth is 0.5 μm or less.

[6] The optical laminate according to any one of [1] to [5], wherein the surface on the functional layer side has a pencil hardness of H or more.

[7] The optical laminate according to any one of [1] to [6], wherein the polyimide resin film contains a polyimide resin, and the polyimide resin contains the formula (1 ), and Y in formula (1) includes the structure shown in formula (3),

[In the formula (1), X represents a divalent organic group, Y represents a tetravalent organic group, and * represents a bonding bond],

[In formula (3), R ¹ independently represent a halogen atom, an alkyl group that may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group, and R ² to R ⁵ independently represent a hydrogen atom, or may have A valent hydrocarbon group having a halogen atom, m independently represent an integer of 0 to 3, n represents an integer of 1 to 4, * represents a bond, but in at least one benzene ring having ^R2 to ^R5 , ^R2 At least 3 of R ⁵ are 1-valent hydrocarbon groups which may have a halogen atom].

[8] A flexible display device comprising the optical laminate according to any one of [1] to [7].

[9] The flexible display device according to [8], further comprising a touch sensor.

[10] The flexible display device according to [8] or [9], further comprising a polarizing plate.

According to the optical layered body of the present invention, it is possible to provide an optical layered body that is less likely to be dented on the surface due to contact with external factors.

Embodiments of the present invention will be described in detail below. In addition, the scope of the present invention is not limited to the embodiments described here, and various changes can be made within the scope not departing from the gist of the present invention. Also, when a plurality of upper and lower limits are described for a specific parameter, any of these upper and lower limits may be combined to form an appropriate numerical range. Also, in this specification, unless otherwise specified, the dent refers to the dent and the permanent dent in the scratch test.

<Optical laminate>

The optical laminated system of the present invention comprises a substrate layer made of a polyimide resin film and a functional layer comprising a cured product of a curable resin, and the yield of the aforementioned optical laminated body when the tensile speed is 100 mm/min The stress is 100 MPa or more.

When the above-mentioned yield stress is less than 100 MPa, it is difficult to reduce the occurrence of dents on the surface due to contact with external factors, and the recovery of the generated dents is not sufficient. From the viewpoint of easier reduction of dishing, the aforementioned yield stress is preferably at least 105 MPa, more preferably at least 110 MPa. From the viewpoint of making it easier to improve the folding resistance of the optical laminate, the yield stress is preferably at most 160 MPa, more preferably at most 150 MPa, and still more preferably at most 140 MPa. The aforementioned yield stress is a value obtained from a stress-strain curve obtained from a tensile test of ASTM D638-14 at a tensile speed of 100 mm/min using the optical layered body as a measurement sample. For example, the values described in the examples can be used Method determination.

The method of adjusting the yield stress of the optical laminate to the above range is not particularly limited, and for example, a polyimide-based resin film having a yield stress described later is used as a base layer, and a cured product containing a curable resin is laminated. The method of the functional layer; the method of using a polyimide-based resin film including a polyimide-based resin described later as a base layer, and laminating a functional layer including a cured product of a curable resin, etc.

The surface of the functional layer side of the optical layered body of the present invention has a pencil hardness of preferably H or higher, more preferably 2H or higher. If the above-mentioned pencil hardness is within the above-mentioned range, it is easier to reduce the occurrence of depressions on the surface due to contact with external factors.

In addition, the above-mentioned pencil hardness is a value measured on conditions of a weight at the time of measurement of 1 kg and a measurement speed of 60 mm/min in accordance with JIS K 5600-5-4:1999.

From the point of view that it is easier to reduce dents on the surface due to contact with external factors, the point of view of the restoration of the generated dents, the point of view of easy improvement of folding resistance, and the point of view of easy prevention of wrinkles and damage, etc., the present invention The tensile elastic modulus of the optical laminate is preferably at least 4.8 GPa, more preferably at least 5.2 GPa, still more preferably at least 6.0 GPa, and usually not more than 100 GPa. In addition, a tensile testing machine can be used for the tensile elastic modulus (test conditions: grip distance 50 mm, tensile speed 10 mm/min).

The optical layered body of the present invention preferably has excellent bending resistance. The bending resistance of the optical laminate of the present invention is preferably at least 200,000 times, more preferably at least 250,000 times, and even more preferably at least 300,000 times, as measured at R=1.5mm. When the number of times of bending resistance is more than the above lower limit, occurrence of cracks, cracks, wrinkles, etc. can be effectively suppressed even if bending is repeated. In addition, the number of times of bending resistance can be measured using a folding tester, and can be measured, for example, by the method described in the examples.

The yellowness (hereinafter referred to as YI value) of the optical layered body of the present invention is preferably less than 3.0. When the YI value is less than 3.0, it is easy to improve the visibility when viewing, for example, an image through the optical layered body. From the viewpoint of improving the visibility of images through the optical layered body more easily, the YI value of the optical layered body of the present invention is preferably 2.8 or less, more preferably 2.6 or less, still more preferably 2.5 or less, more preferably It is -5 or more, more preferably -2 or more. When YI value of an optical layered body is below the said upper limit, transparency will be favorable, and high visibility can be provided when used for the front panel of a display device. In addition, the YI value can be measured using an ultraviolet-visible-near-infrared spectrophotometer relative to the transmittance of light from 300 to 800 nm, and the three excitation values (X, Y, Z) can be obtained, and according to YI=100×(1.2769X-1.0592 Z)/Y formula and calculated. The method of adjusting the YI value of the optical laminate to the above-mentioned range is not particularly limited, and examples include: a method of using a polyimide resin described later, a method of adding a blue pigment, a method of thinning, and a A method for introducing an aromatic ring into a side chain, etc.

The total light transmittance of the optical laminate of the present invention is preferably at least 85%, more preferably at least 88%, even more preferably at least 89%, and most preferably at least 90%. If the total light transmittance is more than the above-mentioned lower limit, the visibility at the time of incorporating an optical layered body into a display device as a front plate will become easy to improve. The optical laminate of the present invention generally exhibits a high total light transmittance, so for example, compared with the case of using a film with a lower transmittance, the luminous intensity of display elements and the like required to obtain constant brightness can be suppressed. Therefore, consumed electric power can be reduced. For example, when the optical layered body of the present invention is incorporated into a display device, bright display tends to be obtained even if the light quantity of the backlight is reduced, and energy can be saved. The upper limit of the total light transmittance is usually 100% or less. Moreover, total light transmittance can be measured using the haze computer (haze computer) based on JISK7361-1:1997, for example. The total light transmittance may be the total light transmittance in the thickness range of the optical laminate described later. Also, in this manual, Excellent optical properties of the optical layered body means high total light transmittance, low haze, and/or low YI value, and improvement or enhancement of transparency is synonymous.

The haze of the optical laminate of the present invention is preferably at most 5%, more preferably at most 4%, more preferably at most 3%, even more preferably at most 2%, particularly preferably at most 1%, and most preferably at most It is less than 0.8%, more preferably less than 0.5%, usually more than 0.01%. If the haze of the optical layered body is in the above-mentioned range, it is easy to improve visibility especially when the optical layered body is incorporated into a display device as a front plate. Moreover, haze can be measured using a haze computer based on JISK7136:2000.

The thickness of the optical laminate of the present invention is preferably at least 10 μm, more preferably at least 15 μm, more preferably at least 20 μm, still more preferably at least 25 μm, particularly preferably at least 30 μm, more preferably at most 200 μm, and more preferably at least 200 μm. 120 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, particularly preferably 60 μm or less, may be a combination of these upper and lower limits. If the thickness of the optical layered body is within the above range, it is easier to increase the yield stress and tensile modulus of the optical layered body. In addition, the thickness of the optical layered body can be measured using a micrometer, for example, by the method described in the examples. The optical laminate of the present invention preferably has a thickness of 15 to 120 μm, more preferably 20 to 100 μm, and more preferably 25 to 80 μm, and the number of times of bending resistance is preferably more than 200,000 times as measured by R=1.5mm, and more preferably More preferably, it is more than 250,000 times, and more preferably, it is more than 300,000 times.

The total light transmittance and haze will change corresponding to the thickness of the optical laminate. The greater the thickness, the lower the total light transmittance and the higher the haze. That is, it is difficult to manufacture an optical layered body having a high total light transmittance and a low haze for a film having a large thickness. In a preferred embodiment of the present invention, the optical laminate of the present invention has a high level of transparency, so it can exhibit high total light transmittance and low haze even if it is thick. Therefore, the thickness of the optical layered body of the present invention is preferably at least 10 μm, more preferably at least 15 μm, still more preferably at least 20 μm, and more preferably at least 20 μm. More preferably, it is at least 25 μm, particularly preferably at least 30 μm, particularly preferably at least 35 μm, and even more preferably at least 40 μm; more preferably at most 100 μm, more preferably at most 80 μm, and more preferably at most 60 μm. The thickness of the optical layered body can be measured with a film thickness gauge, for example, by the method described in the examples.

In this specification, the critical load refers to the maximum load at which a dent is not recognized in an indentation test on an optical layered body.

The depth of the permanent depression is a scratch test on the optical laminate. After the formation of the depression, the depression will recover and become a fixed value after 24 hours.

In the optical layered body of the present invention, the depth of the permanent depression measured with a load of 200 g using a compressive elastic modulus of 3.0 GPa and a front end with a diameter of 0.7 mm on the surface of the functional layer is preferably 0.5 μm or less. , more preferably not more than 0.4 μm, more preferably not more than 0.3 μm, still more preferably not more than 0.2 μm. The details of the method for measuring the depth of the permanent depression are as described in the examples.

For the optical layered body of the present invention, the depth of the permanent depression measured with a load of 1000 g using an auxiliary tool having a compressive modulus of elasticity of 1.0 GPa and a tip with a diameter of 0.7 mm on the side surface of the functional layer is preferably 0.5 μm or less. More preferably, it is 0.4 μm or less, and still more preferably 0.3 μm or less.

(substrate layer)

The optical lamination system of the present invention includes a substrate layer made of a polyimide resin film. The polyimide-based resin contained in the polyimide-based resin film is not particularly limited as long as the above-mentioned optical laminate having a specific yield stress can be obtained. In this specification, polyimide-based resin means one selected from the group consisting of polyimide resin, polyamideimide resin, polyimide precursor resin, and polyamideimide precursor resin. at least one resin. Polyimide resin contains acyl Resins with repeating structural units of imine groups, polyamideimide resins are resins containing repeating structural units containing both imide groups and amido groups. The polyimide precursor resin and the polyamideimide precursor resin are the precursors before imidization of the polyimide resin and the polyamideimide resin obtained respectively by imidization, Also known as polyamide resin. The polyimide-based resin film included in the optical laminate of the present invention may contain one kind of polyimide-based resin, or may contain two or more kinds of polyimide-based resins in combination. From the point of view that the optical laminate of the present invention is easily reduced due to contact with external factors, the polyimide resin contained in the polyimide resin film is preferably polyimide resin or polyamide resin. Amidoimide resin, more preferably polyamideimide resin.

In a preferred embodiment of the present invention, the polyimide-based resin is preferably an aromatic-based resin from the viewpoints of reducing dents caused by contact with external factors and improving chemical stability. In the present specification, the aromatic resin means a resin in which the structural units contained in the polyimide resin are mainly aromatic structural units.

In the above-mentioned preferred embodiment, from the point of view of reducing the depression caused by contact with external factors and improving the chemical stability more easily, the structural unit derived from the aromatic monomer is compared with the imide The proportion of all structural units contained in the resin is preferably at least 60 mol%, more preferably at least 70 mol%, more preferably at least 80 mol%, and still more preferably at least 85 mol%. Here, the structural unit derived from an aromatic monomer refers to a structure derived from a monomer at least partially containing an aromatic structure (such as an aromatic ring) and at least partially containing an aromatic structure (such as an aromatic ring) unit. As an aromatic monomer, an aromatic tetracarboxylic acid compound, an aromatic diamine, an aromatic dicarboxylic acid, etc. are mentioned, for example.

In a preferred embodiment of the present invention, the polyimide-based resin may be a polyimide-based resin comprising a structural unit represented by formula (1).

[In the formula (1), Y represents a 4-valent organic group, X represents a 2-valent organic group, and * represents a bonding bond],

And Y in the formula (1) includes the structure shown in the formula (3).

[In formula (3), R ¹ independently represent a halogen atom, an alkyl group that may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group, and R ² to R ⁵ independently represent a hydrogen atom, or may have A valent hydrocarbon group with a halogen atom,

m independently represent an integer from 0 to 3,

n represents an integer from 1 to 4,

* represents a bond, but at least 3 of R ² to R ⁵ are valent hydrocarbon groups that may have a halogen atom among at least one benzene ring having R ² to R ⁵ ].

In formula (1), Y independently represents a tetravalent organic group, preferably a tetravalent organic group with 4 to 80 carbon atoms, more preferably a tetravalent organic group with 4 to 60 carbon atoms having a ring structure . Examples of the cyclic structure include an alicyclic ring, an aromatic ring, and a heterocyclic structure. The aforementioned organic group can be an organic group in which the hydrogen atom in the organic group can be replaced by a substituent, and the substituent is preferably a halogen atom, a valent hydrocarbon group that can have a halogen atom, such as an alkoxy group such as an alkyl group or an aryl group, or Aryloxy, in this case, may have a halogen The carbon number of the subvalent hydrocarbon group, alkoxy group or aryloxy group is preferably 1-8. The polyimide resin of one embodiment of the present invention may contain plural kinds of Y, and the plural kinds of Y may be the same or different from each other.

Among polyimide-based resins, it is preferable that Y in formula (1) includes the structure represented by formula (3). In the formula (3), R ¹ independently represent a halogen atom, an alkyl group which may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group. The halogen atom includes, for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Alkyl can be for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second butyl, third butyl, n-pentyl, 2-methyl-butyl, 3 -methylbutyl, 2-ethyl-propyl, n-hexyl and the like. Alkoxy can be exemplified by methoxy, ethoxy, propyloxy, isopropyloxy, n-butoxy, isobutoxy, second butoxy, third butoxy, pentyloxy group, hexyloxy group, cyclohexyloxy group, etc. The aryl group includes, for example, phenyl, tolyl, stubyl, naphthyl, biphenyl and the like. The aryloxy group includes, for example, phenoxy, naphthyloxy, biphenyloxy and the like. R ¹ preferably independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. The aryloxy group of 12. For an optical laminate having a polyimide-based resin film, from the viewpoint that it is easier to reduce depression due to contact with external factors and to improve transparency, R ¹ is preferably independently of each other. The alkyl or alkoxy group of a halogen atom is more preferably an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms which may have a halogen atom.

In formula (3), from the viewpoint of easily reducing dents and improving transparency, m independently represents an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.

In formula (3), R ² , R ³ , R ⁴ and R ⁵ independently represent a hydrogen atom or a valent hydrocarbon group that may have a halogen atom, and in at least one benzene ring having R ² to R ⁵ , R At least 3 of ² to R ⁵ are 1-valent hydrocarbon groups which may have a halogen atom. Examples of the hydrocarbon group include aromatic hydrocarbon groups, alicyclic hydrocarbon groups, and aliphatic hydrocarbon groups. Examples of the aromatic hydrocarbon group include aryl groups such as phenyl, tolyl, stubyl, naphthyl, and biphenyl. Examples of the alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl and cyclohexyl, and the like. The aliphatic hydrocarbon group can for example be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second butyl, third butyl, n-pentyl, 2-methyl-butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tertiary octyl, n-nonyl, n-decyl and other alkyl groups, etc. Examples of the halogen atom include those described above. R ² to R ⁵ preferably independently represent a hydrogen atom, or an aryl group having 6 to 12 carbons which may have a halogen atom, a cycloalkyl group having 4 to 8 carbons, or an alkyl group having 1 to 6 carbons. From the viewpoint of the solubility of the resin in solvents and the ease of reducing the depression of the optical layered body and the ease of improving transparency, ^R2 to ^R5 are preferably independently hydrogen atoms or alkyl groups that may have halogen atoms, more preferably It is preferably a hydrogen atom or an alkyl group of 1 to 6 which may have a halogen atom, and is more preferably a hydrogen atom or an alkyl group of 1 to 3 which may have a halogen atom.

Among the at least one benzene ring having R ² to R ⁵ in formula (3), when at least three of R ² to R ⁵ are valent hydrocarbon groups which may have a halogen atom, the optical layered body tends to reduce cratering. In addition, the solubility of the polyimide-based resin in solvents can be improved.

From the viewpoint of the solubility of the resin in solvents and the ease of reducing dents and improving transparency in the optical layered body, when n is 2 or more, preferably among at least 2 benzene rings having ^R2 to ^R5 , At least 3 of R ² to R ⁵ are a valent hydrocarbon group that may have a halogen atom; more preferably, in all benzene rings that have R ² to R ⁵ , at least 3 of R ² to R ⁵ are a valent hydrocarbon group that may have a halogen atom One-valent hydrocarbon group of atoms.

In formula (3), n represents an integer of 1 to 4, and from the viewpoint of easily improving the tensile elastic modulus and transparency of the polyimide-based lipid film and easily reducing the depression in the optical laminate, n Preferably it is an integer of 1 to 3, more preferably 2 or 3, still more preferably 2. In addition, the structural unit represented by formula (1) may contain one or more structures represented by formula (3) as Y.

In a preferred embodiment of the present invention, formula (3) is represented by formula (3').

[In the formula (3'), * represents the bonding bond]

That is, at least a part of the plurality of Ys in formula (1) is represented by formula (3'). If it is this form, it will become easy to reduce dents in an optical layered body, and it will become easy to improve transparency.

As far as an embodiment of the present invention is concerned, in the structural unit shown in formula (1), relative to the total mole amount of the structural unit shown in formula (1), Y is the better ratio of structural unit shown in formula (3) More than 10 mol%, more preferably more than 30 mol%, more preferably more than 45 mol%, more preferably more than 50 mol%, especially preferably more than 55 mol%, preferably not Up to 70 mole %, more preferably less than 65 mole %, more preferably less than 62 mole %, most preferably less than 60 mole %. If the ratio of Y being the structural unit represented by formula (3) is more than the above-mentioned lower limit, it becomes easy to reduce the dishing in an optical layered body. Moreover, the transparency of an optical layered body will become easy to improve as long as the ratio which Y is a structural unit represented by formula (3) is below the said upper limit. Y is the ratio of the structural unit represented by the formula (3), which can be measured, for example, using ¹ H-NMR, or can be calculated from the feed ratio of the raw materials.

The polyimide-based resin preferably further includes a structure represented by formula (5) as Y in formula (1).

[In formula (5), B represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group that may have a halogen atom, -SO ₂ -, -S-, -CO-, -COO-, - PO-, -PO ₂ -, -N(R ^B1 )- or -Si(R ^B2 ) ₂ -,

R ^B1 and R ^B2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom,

^R independently represent a halogen atom, an alkyl group that may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group,

t independently represent an integer from 0 to 3,

＊ means a bonding key].

When the structure represented by the formula (5) is further included as Y in the formula (1), it is easier to reduce the dishing of the optical layered body, and it is easier to improve the transparency.

In the formula (5), R ⁷ independently represent a halogen atom, an alkyl group which may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group. Halogen atoms, alkyl groups which may have halogen atoms, alkoxy groups, aryl groups, and aryloxy groups are exemplified by R ¹ in formula (3), respectively. From the standpoint that it is easy to reduce the depression of the optical layered body and improve the transparency, ^R7 is independent of each other, preferably an alkyl group having 1 to 6 carbon atoms that may have a halogen atom, more preferably a carbon that may have a halogen atom Alkyl groups with numbers 1 to 3.

In the formula (5), t represents an integer of 0 to 3, and preferably represents an integer of 0 to 2, and more preferably represents 0 or 1, from the viewpoint that the sagging of the optical layered body can be easily reduced and the transparency can be easily improved. and more preferably 0.

B in the formula (5) independently represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group that may have a halogen atom, -SO ₂ -, -S-, -CO-, -COO- , -PO-, -PO ₂ -, -N(R ^B1 )- or -Si(R ^B2 ) ₂ -, R ^B1 and R ^B2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom.

Examples of the divalent hydrocarbon group which may have a halogen atom include divalent groups obtained by removing one hydrogen atom from the valent hydrocarbon groups which may have a halogen atom among R ² to R ⁵ in formula (3). A divalent hydrocarbon group that may have a halogen atom can replace two hydrogen atoms from the hydrogen atoms contained in the group to form a ring, that is, the two hydrogen atoms can be replaced by bonds and the two bonds can be connected to form a ring. A ring is formed, and the ring may, for example, be a cycloalkane ring having 3 to 12 carbon atoms. Also, for the alkyl group that may ^have a halogen atom in R ^B1 and R B2 in -N(R ^B1 )- and -Si(R ^B2 ) ₂ - included in B in formula (5), it may be Examples of the alkyl group that may have a halogen atom in R ¹ in the above formula (3) are exemplified.

From the standpoint of reducing the dent of the optical layered body and improving the transparency, B in the formula (5) preferably includes a single bond or a divalent hydrocarbon group that may have a halogen atom, more preferably a single bond, - CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, still more preferably a single bond, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, more preferably a single bond or -C(CF ₃ ) ₂ -, particularly preferably -C(CF ₃ ) ₂ -.

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

[In the formula (5'), * represents the bonding bond]

That is, in a preferred aspect, at least a part of the plurality of Ys in formula (1) is represented by formula (5'). If it is this form, it becomes easier to reduce the dishing of an optical layered body, and it becomes easier to improve transparency.

In the structural unit shown in formula (1), Y in the formula (1) is the ratio of the structural unit shown in the formula (3), relative to Y in the formula (1) is the structural unit shown in the formula (5) 1 mol, preferably 0.1 mol or more, more preferably 0.4 mol or more, more preferably 1.0 mol or more, preferably 2.3 mol or less, more preferably 1.9 mol or less, and more preferably 1.7 mol or less Mole below. If the ratio of Y in formula (1) to the structural unit shown in formula (3) to Y in formula (1) is the structural unit shown in formula (5) is more than the above-mentioned lower limit, then it is easy to increase the polyimide. It is the tensile elastic modulus of the resin film. Moreover, if this ratio is below the said upper limit, it will become easier to reduce the dishing of an optical layered body, and it will become easier to improve transparency. Y in the formula (1) is the ratio of the structural unit shown in the formula (3) relative to the Y in the formula (1) that is the structural unit shown in the formula ⁽ 5). The feed ratio is calculated.

In the structural unit shown in formula (1), Y in the formula (1) with respect to the total mole amount of structural unit shown in formula (1) is the ratio of structural unit shown in formula (5) is preferably more than 30 moles %, more preferably more than 35 mol%, more preferably more than 38 mol%, more preferably more than 40 mol%, preferably less than 90 mol%, more preferably less than 70 mol% , and more preferably less than 55 mole %, more preferably less than 50 mole %, especially preferably less than 45 mole %.

With respect to the total molar amount of the structural unit represented by the formula (1), if the ratio of Y being the structural unit represented by the formula (5) is more than the above-mentioned lower limit, it is easier to reduce the depression of the optical layered body, and it is easier to improve the transparency sex. Moreover, if this ratio is below the said upper limit, it will become easy to raise the tensile elastic modulus of a polyimide-type resin film and an optical laminated body. In addition, Y in the formula (1) is a ratio of the structural unit represented by the formula (5), which can be measured using ¹ H-NMR, for example, or can be calculated from the charging ratio of the raw materials.

In an embodiment of the present invention, relative to the total molar amount of the structural unit shown in the formula (1), Y is the structural unit shown in the formula (3) and Y is the total ratio of the structural unit shown in the formula (5) is better It is at least 50 mol%, more preferably at least 70 mol%, more preferably at least 90 mol%, more preferably at most 100 mol%. If the total ratio is in the above range, the tensile elastic modulus and transparency of the polyimide resin film will be easily improved, and the dents of the optical layered body will be more easily reduced. In addition, this total ratio can be measured using ¹ H-NMR, for example, or can be calculated from the charging ratio of raw materials.

In formula (1), in terms of Y, in addition to the structure shown in formula (3), it can include the structure shown in formula (5), as well as formula (20), formula (21), formula (22) , formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and the structure shown in formula (29).

[In formula (20) to formula (29), * represents a bond, W ¹ represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group that may have a halogen atom, such as -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, etc., -Ar-, -SO ₂ -, -S-, -CO -, -PO-, -PO ₂ -, -N(R ^W1 )-, -Si(R ^W2 ) ₂ -, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ - Ar-, -Ar-C(CH ₃ ) ₂ -Ar-, or -Ar-SO ₂ -Ar-. Ar represents an arylylene group having 6 to 20 carbon atoms which may have a fluorine atom, and a specific example thereof is a phenylene group. R ^W1 and R ^W2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom. Also, the hydrogen atoms in the groups represented by formula (20) to formula (29) can be substituted by methyl, fluorine, chlorine or trifluoromethyl; . Also, the ring hydrogen atoms in formula (20) to formula (29) may be substituted by an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons or an aryl group having 6 to 12 carbons].

Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, and the aryl group having 6 to 12 carbon atoms include those exemplified for R ¹ in the above formula (3).

From the standpoint that it is easier to reduce the sag of the optical laminate, it is easier to increase the tensile elastic modulus, and it is easier to improve the transparency, among the groups represented by the formula (20) to the formula (29), the formula (26), The group represented by formula (28) or formula (29), more preferably the group represented by formula (26). In addition, from the standpoints that it is easier to reduce the dent of the optical layered body, it is easier to increase the tensile elastic modulus, and it is easier to improve the transparency, W ¹ preferably represents a single bond, -O-, -CH ₂ -, - CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, more preferably a single bond, -O-, -CH ₂ -, -CH (CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, and more preferably a single bond, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, Still more preferably, it is a single bond or -C(CF ₃ ) ₂ -, and most preferably is -C(CF ₃ ) ₂ -.

In formula (1), X represents a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms.

In the present invention, in terms of polyimide-based resins, X in the formula (1) is easier to reduce the sag of the optical layered body, to increase the tensile modulus of elasticity, and to improve the transparency more easily. Preferably, it contains at least 1 sort(s) of a divalent aromatic group, a divalent alicyclic group, and a divalent aliphatic group, More preferably, it contains a divalent aromatic group. The divalent aromatic group can be, for example: a divalent aromatic hydrocarbon group in which one of the hydrogen atoms in the aromatic hydrocarbon groups exemplified by ^R2 to ^R5 in the above formula (3) is replaced with a bonding bond; And a group in which at least one or more of the divalent aromatic hydrocarbon groups are bonded via a linking group (for example, a linking group such as V ¹ described later). The divalent alicyclic group can be, for example, a divalent alicyclic group in which one of the hydrogen atoms in the alicyclic hydrocarbon group exemplified by ^R2 to ^R5 in the above formula (3) is replaced with a bond. a hydrocarbon group; and a group in which at least one of the divalent alicyclic hydrocarbon groups is bonded via a linking group (for example, a linking group such as V ¹ described later). The divalent aliphatic group can be, for example, a divalent aliphatic hydrocarbon group in which one hydrogen atom is replaced by a bond among the hydrogen atoms in the aliphatic hydrocarbon groups exemplified by ^R2 to ^R5 in the above formula (3); and A group in which at least one or more of the divalent aliphatic hydrocarbon groups are bonded via a linking group (for example, a linking group such as V ¹ described later).

X in the formula (1) is preferably a divalent organic group with 4 to 40 carbons having ring structures such as alicyclic rings, aromatic rings, and heterocyclic structures, more preferably a divalent aromatic group with 4 to 40 carbon atoms group and a divalent alicyclic group having 4 to 40 carbon atoms, and more preferably a divalent aromatic group having 4 to 40 carbon atoms. As for the organic group, the hydrogen atoms in the organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. In one embodiment of the present invention, the polyimide-based resin may contain multiple types of X, and the multiple types of X may be the same or different from each other. X can be shown in formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) and formula (18) group; a group in which the hydrogen atom in the group represented by the formula (10) to the formula (18) is substituted by a methyl group, a fluorine group, a chlorine group or a trifluoromethyl group; and a chain hydrocarbon group having 6 or less carbon atoms.

[In formula (10) to formula (18),

＊ means bond key,

V ¹ , V ² and V ³ independently represent a single bond, -O-, -S-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -CO- or -N(Q)-. Here, Q represents a C1-C12 monovalent hydrocarbon group which may have a halogen atom].

The valent hydrocarbon group having 1 to 12 carbon atoms which may have a halogen atom may be exemplified above as the valent hydrocarbon group which may have a halogen atom in R ² to R ⁵ of the formula (3).

As an example, V ¹ and V ³ are single bonds, -O- or -S-, and V ² is -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - or -SO ₂ -. The bonding positions of V ¹ and V ² relative to each ring, and the bonding positions of V ² and V ³ relative to each ring are independent of each other, preferably meta or para, more preferably para . Also, the hydrogen atoms on the rings in the formulas (10) to (18) may be substituted with an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, and the aryl group having 6 to 12 carbon atoms include those exemplified for R ¹ in the above formula (3).

In a preferred embodiment of the present invention, the polyimide-based resin may contain a structure represented by formula (4) as X in formula (1).

[In formula (4), A represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group that may have a halogen atom, -SO ₂ -, -S-, -CO-, -PO-, - PO ₂ -, -N(R ^A1 )- or -Si(R ^A2 ) ₂ -,

R ^A1 and R ^A2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom,

^R independently represent a halogen atom, an alkyl group that may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group,

s independently represent an integer from 0 to 4,

＊ means a bonding key].

In this form, it is easy to improve the tensile elastic modulus and transparency of the polyimide-based resin film and the optical layered body, and it is easier to reduce dents in the optical layered body. In addition, the structural unit represented by formula (1) may contain one or more structures represented by formula (4) as X.

R ⁶ each independently represent a halogen atom, an alkyl group which may have a halogen atom, an alkoxy group, an aryl group, or an aryloxy group. Halogen atoms, alkyl groups which may have halogen atoms, alkoxy groups, aryl groups, and aryloxy groups are exemplified by R ¹ in the above formula (3).

Among them, from the viewpoint of improving the tensile elastic modulus and transparency of the polyimide-based resin film and the optical laminate, and making it easier to reduce the sag of the optical laminate, R ⁶ is independent of each other, and is preferred. It is an alkyl group having 1 to 6 carbons or a halogenated alkyl group having 1 to 6 carbons, more preferably an alkyl group having 1 to 6 carbons or a fluoroalkyl group having 1 to 6 carbons, more preferably a perfluoroalkyl group. In a preferred form, R ⁶ are independently methyl, chloro or trifluoromethyl. s independently represents an integer of 0 to 4, and it is easier to improve the tensile elastic modulus and transparency of the polyimide resin film and the optical laminate, and it is easier to reduce the depression of the optical laminate. It is preferably an integer of 1 to 3, more preferably 1 or 2, still more preferably 1.

As far as the preferred embodiment of the invention is concerned, it is preferred that in each benzene ring, s is 1, and R ⁶ is substituted in the positive position based on -A-, and R ⁶ is methyl, fluoro, or chloro or trifluoromethyl.

In the formula (4), the positions of the bonding bonds are independent of each other, from the point of view that it is easy to improve the tensile modulus and transparency of the polyimide resin film and the optical laminate, and it is easy to reduce the depression of the optical laminate. See, based on -A-, it's better to be meta or para, more preferably para.

A in the formula (4) independently represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group which may have a halogen atom, -SO ₂ -, -S-, -CO-, -PO- , -PO ₂ -, -N( ^RA1 )- or -Si( ^RA2 ) ₂ -, R ^A1 and R ^A2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom.

Examples of the divalent hydrocarbon group which may have a halogen atom include divalent groups obtained by removing one hydrogen atom from the valent hydrocarbon groups which may have a halogen atom in R ² to R ⁵ in formula (3). A divalent hydrocarbon group that may have a halogen atom can replace two hydrogen atoms from the hydrogen atoms contained in the group to form a ring, that is, replace the two hydrogen atoms with bonds and connect the two bonds to form a ring ring, the ring may, for example, be a cycloalkane ring having 3 to 12 carbon atoms. In addition, the alkyl group that may have a halogen atom in R ^A1 and R ^A2 of -N(R ^A1 )- and -Si(R ^A2 ) ₂ - contained in A in formula (4) can be exemplified by the above formula ( 3) The alkyl group which may have a halogen atom in ^R1 is exemplified.

From the viewpoints that it is easier to reduce the sag of the optical laminate, it is easier to increase the tensile modulus, and it is easier to improve the transparency, A in the formula (3) is preferably a single bond, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, more preferably a single bond, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, still more preferably a single bond or -C(CF ₃ ) ₂ -, particularly preferably a single bond.

In a preferred embodiment of the present invention, from the viewpoint of improving the tensile elastic modulus and transparency of the polyimide resin film and the optical laminate, and making it easier to reduce the dent of the optical laminate, the formula ( In 4), R ⁶ independently represents a halogenated alkyl group having 1 to 6 carbons, s represents 1 or 2, and A represents a single bond, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -.

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

That is, at least a part of the plurality of Xs in formula (1) is preferably represented by formula (4'). With this form, it is easier to reduce the dent of the optical layered body, it is easier to increase the tensile modulus, and it is easier to improve the transparency.

In an embodiment of the present invention, when the structure shown in formula (4) is included as X in formula (1), relative to the total molar amount of the structural unit shown in formula (1), X is represented by formula (4) The ratio of the structural unit is preferably more than 30 mole%, more preferably more than 50 mole%, more preferably more than 70 mole%, and more preferably more than 80 mole%, especially preferably 90 mole% above, preferably 100 mol% or less. When the proportion of X being the structural unit represented by the formula (4) is within the above range, it is easier to reduce the sinking of the optical layered body, and it is easier to further increase the tensile modulus of elasticity. The ratio system in which X is a structural unit represented by formula (4) can be measured using ¹ H-NMR, for example, and can also be calculated from the feed ratio of raw materials.

In a preferred embodiment of the present invention, the plural structural units represented by formula (1) preferably further include Y being a structural unit represented by formula (9) in addition to Y being a structural unit represented by formula (5). When Y is further contained as a structural unit represented by the formula (9), it is easier to reduce the sinking of the optical layered body, and it is easier to further increase the tensile modulus of elasticity.

The polyimide-based resin comprising the structural unit represented by formula (1) may be a polyimide-imide resin further having a structural unit represented by formula (2).

[In the formula (2), Z and X independently represent a divalent organic group, and * represents a bonding bond]

The formula (2) will be described below. In this aspect, it is easier to reduce cracking and whitening when folding the optical layered body, and it is easier to further increase the modulus of elasticity, compared to polyamideimide resin. Containing the amount of all structural units, the ratio of the amide component contained in the polyamide imide resin is preferably more than 5 mole%, more preferably 10 mole%, and more preferably more than 15 mole%, and then More preferably, it is more than 20 mol%.

In formula (2), Z is a divalent organic group, preferably an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons (among these groups The hydrogen atom can be replaced by a halogen atom, preferably a divalent organic group with 4 to 40 carbon atoms, more preferably an alkyl group with 1 to 6 carbon atoms, or an alkoxy group with 1 to 6 carbon atoms A divalent organic group with 4 to 40 carbons having a ring structure substituted by an aryl group with 6 to 12 carbon atoms (the hydrogen atoms in these groups may be replaced by halogen atoms, preferably fluorine atoms). In addition, examples of an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons are the same as those for R ^3a and R ^3b in formula (3) described later. . Examples of the cyclic structure include an alicyclic ring, an aromatic ring, and a heterocyclic structure. The organic group of Z can be for example formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) and the bonding bond of the group shown in formula (29), the two non-adjacent bonding bonds are replaced by a hydrogen atom group and a divalent chain hydrocarbon group with a carbon number of 6 or less. The heterocyclic structure of Z can be exemplified A group having a thiophene ring skeleton. From the viewpoint of easily reducing the YI value of the polyimide resin film, the viewpoint of easily improving the total light transmittance, and the viewpoint of easily reducing the haze, the ring structure in Z is preferably from formula (20) to The group represented by formula (29) and the group having a thiophene ring skeleton are more preferably groups represented by formula (26), formula (28) and formula (29).

[In formula (20) to formula (29), W ¹ represents 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-, here, Ar independently represents an aryl group with 6 to 20 carbon atoms (such as phenylene group) in which a hydrogen atom can be substituted by a fluorine atom ), * represents the bonding key].

The organic group of Z is more preferably formula (20'), formula (21'), formula (22'), formula (23'), formula (24'), formula (25'), formula (26'), formula (27'), a divalent organic group represented by formula (28') and formula (29').

[In the formula (20') to the formula (29'), W ¹ and * are defined in the formula (20) to the formula (29)]

Also, the hydrogen atom on the ring in formula (20) to formula (29) and formula (20') to formula (29') can be an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, Or an aryl group having 6 to 12 carbon atoms [the hydrogen atoms in these groups may be replaced by halogen atoms (preferably fluorine atoms)] to replace.

From the standpoint of improving the film-forming properties of the varnish and the uniformity of the film, the polyamideimide resin has the formula (2) where Z is any one of the above-mentioned formula (20') to formula (29'). When the structural unit is shown, especially when Z in the formula (2) has the structural unit shown in the following formula (3'), it is preferred that the polyamideimide resin further has the following formula in addition to the structural unit (d1) represents a structural unit derived from a carboxylic acid.

[In formula (d1), R ⁴¹ is independently a group or a hydrogen atom defined by R ^3a in the following formula (3), R ⁴² represents R ⁴¹ or -C(=O)-*, * represents a bond ]. The structural unit (d1) specifically includes a structural unit in which both R ⁴¹ and R ⁴² are hydrogen atoms (derived from a structural unit of a dicarboxylic acid compound), R ⁴¹ is both a hydrogen atom and R ⁴² represents -C(= Structural units of O)-* (structural units derived from tricarboxylic acid compounds), etc.

The polyamideimide resin can contain plural kinds of Z as Z in the formula (2), and the plural kinds of Z may be the same or different from each other. In particular, from the standpoint of easily improving the tensile modulus of the film and improving the optical properties, Z in formula (2) preferably has at least the structural unit shown in formula (6), more preferably has at least the formula The structural unit shown in (6').

[In formula (6), R ^3a and R ^3b independently represent an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons, R ^3a and R ^3b The contained hydrogen atoms may independently be replaced by halogen atoms, and W independently represent single bonds, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, R ⁹ represents a hydrogen atom, carbon number 1 to 12 which may be substituted by a halogen atom A monovalent hydrocarbon group, s is an integer from 0 to 4, t is an integer from 0 to 4, u is an integer from 0 to 4, and * represents a bond].

[In formula (6'), R ^3a , R ^3b , s, t, u, W and * are those defined in formula (6)]

Also, in this specification, so-called "polyamide imide resin has Z in formula (2) is the structural unit shown in formula (6)" and "polyamide imide resin has formula (6) Showing the structure as "Z" in the formula (2) has the same meaning, which means that among the plurality of structural units shown in the formula (2) that the polyamide imide resin can contain, Z of at least a part of the structural units is the formula (6 ) shown.

This record form can also be applied to other records.

In formula (6) and formula (6'), W independently represents 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 )-, based on the bending resistance of polyimide resin films and optical laminates From the standpoint, it is preferably -O- or -S-, more preferably -O-.

R ^3a and R ^3b independently represent an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. Alkyl groups with 1 to 6 carbons can be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, second-butyl, third-butyl, n-pentyl, 2-methyl-butyl , 3-methylbutyl, 2-ethyl-propyl, n-hexyl, etc. Alkoxy groups with 1 to 6 carbons can be exemplified by methoxy, ethoxy, propyloxy, isopropyloxy, butoxy, isobutoxy, tert-butoxy, pentyloxy , Hexyloxy, Cyclohexyloxy, etc. The aryl group having 6 to 12 carbon atoms includes, for example, phenyl, tolyl, stubyl, naphthyl, biphenyl and the like. From the viewpoint of the tensile modulus of elasticity, surface hardness and flexibility of the polyimide resin film and the optical laminate, R ^3a and R ^3b preferably independently represent an alkyl group having 1 to 6 carbon atoms or The alkoxy group having 1 to 6 carbons more preferably represents an alkyl group having 1 to 3 carbons or an alkoxy group having 1 to 3 carbons. Here, hydrogen atoms contained in R ^3a and R ^3b may be independently substituted with halogen atoms.

R ⁹ represents a hydrogen atom, a valent hydrocarbon group having 1 to 12 carbons which may be substituted by a halogen atom. Monovalent hydrocarbon groups with 1 to 12 carbons can be exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, second-butyl, third-butyl, n-pentyl, 2-methyl-butyl group, 3-methyl-butyl group, 2-ethyl-propyl group, n-hexyl group, n-heptyl group, n-octyl group, tertiary octyl group, n-nonyl group, n-decyl group, etc., which may be substituted by halogen atoms. Examples of the aforementioned halogen atom include fluorine atom, chlorine atom, bromine atom, iodine atom and the like.

In formula (6) and formula (6'), t and u are independently an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 1 or 2.

In the formula (6) and the formula (6'), s is an integer in the range of 0 to 4, if s is within this range, it is easy to improve the tensile modulus of elasticity of the polyimide resin film and the optical laminate And bending resistance, and it is easier to reduce the sag of the optical laminate. In formula (6) and formula (6'), s is preferably from 0 to 3 from the viewpoint of improving the tensile elastic modulus and bending resistance of the polyimide resin film and the optical laminate more easily. The integer in the range is more preferably an integer in the range of 0 to 2, more preferably 0 or 1, still more preferably 0. In the polyamideimide resin, Z may contain one or more structural units represented by formula (6) or formula (6').

In a preferred embodiment of the present invention, from the viewpoint of improving the tensile elastic modulus and bending resistance of the polyimide resin film and the optical laminate, and reducing the YI value, Z is preferably represented by the formula ( 6) or represented by formula (6′), wherein, s is 0, and u is preferably 1 to 3, more preferably 1 or 2. Also, in addition to Z shown in formula (6) or formula (6') having a structural unit shown in formula (2) and this formula (2) has s as 0, preferably further has the formula (d1) shown in the above Structural units.

When polyamide imide resin has structural unit shown in formula (6) or formula (6 '), its ratio is represented by structural unit shown in formula (1) and formula (2) with polyamide imide resin When the total of the structural units is 100 mol %, it is preferably at least 20 mol %, more preferably at least 30 mol %, more preferably at least 40 mol %, and more preferably at least 50 mol % , especially preferably more than 60 mol%, more preferably less than 90 mol%, more preferably less than 85 mol%, and more preferably less than 80 mol%. When the ratio of the structural unit represented by formula (6) or formula (6') is more than the above-mentioned lower limit, the tensile elastic modulus and bending resistance of the polyimide-based resin film and the optical laminate can be easily improved. If the proportion of the structural unit represented by the formula (6) or the formula (6') is below the above-mentioned upper limit, the viscosity of the resin-containing varnish caused by the hydrogen bond between the amide bonds of the formula (6) can be suppressed Rising, it is easy to improve the processability of the film. Also, the ratio of the structural unit represented by formula (1), formula (2), formula (6) or formula (6') can be measured using ¹ H-NMR, for example, or can be calculated from the charging ratio of raw materials.

In a preferred embodiment of the present invention, Z in the polyamide imide resin is preferably more than 30 mole %, and the structural unit represented by formula (6) or formula (6') in which s is 0 to 4 , more preferably at least 40 mol%, more preferably at least 45 mol%, and more preferably at least 50 mol%. If the above-mentioned lower limit of Z is more than the structural unit shown in formula (6) or formula (6') in which s is 0 to 4, then it is easy to improve the tensile elastic modulus and the tensile modulus of the polyimide resin film and the optical laminate Bending resistance. Also, as long as it is a structural unit represented by formula (6) or formula (6') in which s is 0 to 4 in the polyamideimide resin, Z is less than 100 mol%. Moreover, the proportion of the structural unit represented by formula (6) or formula (6') in which s is 0 to 4 in the resin can be measured using ¹ H-NMR, for example, or can be calculated from the charging ratio of raw materials.

When polyimide resin is polyamide imide resin, relative to 1 mole of structural unit shown in formula (1), the content of structural unit shown in formula (2) is preferably more than 0.1 mole, more preferably It is 0.5 mol or more, more preferably 1.0 mol or more, still more 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 the formula (2) is more than the above lower limit, the impact resistance and tensile modulus of the polyimide-based resin film and the optical layered body will be easily improved. Also, if the content of the structural unit represented by the formula (2) is below the above-mentioned upper limit, it is easy to suppress the thickening caused by the hydrogen bond between the amide bonds in the formula (2), and it is easy to improve the polyimide resin film. The processability.

The polyimide-based resin may comprise the structural unit shown in formula (30) and/or the structural unit shown in formula (31), and may also be a structure other than the structure shown in formula (1) and formula (2) as required In addition to the unit, a structural unit represented by formula (30) and/or a structural unit represented by formula (31) are included.

In the formula (30), Y ¹ is a tetravalent organic group, preferably an organic group in which the hydrogen atoms in the organic group can be replaced by a hydrocarbon group or a fluorine-substituted hydrocarbon group. ^Y can be for example formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and A group represented by formula (29), a group in which the hydrogen atoms in the groups represented by formula (20) to formula (29) are substituted with methyl, fluorine, chlorine or trifluoromethyl, and a group having 6 or less tetravalent carbons The chain hydrocarbon group. In one embodiment of the present invention, the polyimide-based resin may contain multiple types of Y ¹ , and the multiple types of Y ¹ may be the same or different from each other.

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

In formula (30) and formula (31), X ¹ and X ² are independently divalent organic groups, preferably organic groups in which hydrogen atoms in the organic groups can be replaced by hydrocarbon groups or fluorine-substituted hydrocarbon groups. ^X1 and ^X2 can be, for example, the above formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) and formula The group represented by (18); the hydrogen atom in the group represented by the formula (10) to the formula (18) is replaced by a methyl group, a fluorine group, a chlorine group or a trifluoromethyl group; and a chain having 6 or less carbon atoms Hydrocarbyl.

In one embodiment of the present invention, the polyimide resin is a structural unit represented by formula (1) and/or formula (2), and a structural unit represented by formula (30) and/or formula (31) if necessary constituted. Also, from the viewpoint of reducing the sagging of the optical laminate, bending resistance, and easily improving the transparency and tensile modulus of the polyimide resin film, among the above polyimide resins, based on the formula ( 1) and formula (2), and all structural units shown in formula (30) and formula (31) as required, the proportion of structural units shown in formula (1) and formula (2) is preferably more than 80 mole % , more preferably more than 90 mole%, and more preferably more than 95 mole%. Also, in polyimide resins, based on formula (1) and formula (2), and all structural units shown in formula (30) and/or formula (31) as required, formula (1) and formula (2 ) The ratio of the structural unit represented by ) is usually 100% or less. In addition, the said ratio can be measured using ¹ H-NMR, for example, and can also be calculated from the charging ratio of a raw material.

In one embodiment of the present invention, the content of the polyimide-based resin in the polyimide-based resin film is preferably at least 10 parts by mass, more preferably at least 30 parts by mass, and even more preferably 100 parts by mass of the film. Preferably, it is 50 mass parts or more, More preferably, it is 99.5 mass parts or less, More preferably, it is 95 mass parts or less. If the content of the polyimide resin is within the above range, it is easy to improve the chemical stability, optical properties, impact resistance and tensile elastic modulus of the polyimide resin film, and it is easier to reduce the optical laminate. the depression.

From the standpoint of reducing the dent of the optical laminate and improving the tensile elastic modulus and bending resistance, the weight average molecular weight of the polyimide resin is preferably 200,000 or more in terms of standard polystyrene, more preferably It is above 230,000, more preferably above 250,000, still more preferably above 270,000, particularly preferably above 280,000, and most preferably above 300,000. Also, from the standpoint of improving the solubility of the resin to solvents and improving the extensibility and processability of the polyimide resin film, the weight average molecular weight of the polyimide resin is preferably 1,000,000 or less. More preferably, it is 800,000 or less, more preferably 700,000 or less, and still more preferably 500,000 or less. The weight average molecular weight can be calculated|required in standard polystyrene conversion, for example by GPC measurement.

In a preferred embodiment of the present invention, the polyimide resin contained in the polyimide resin film may contain halogen atoms such as fluorine atoms, which can be introduced through the above-mentioned fluorine-containing substituents, etc. . When the polyimide-based resin contains a halogen atom, the tensile modulus of the polyimide-based resin film and the optical laminate tends to increase and the YI value decreases. When the YI value of a polyimide-type resin film is low, it becomes easy to improve the transparency and visibility of the said film. The halogen atom is preferably a fluorine atom. Preferred fluorine-containing substituents for making the polyimide resin contain fluorine atoms include fluorine and trifluoromethyl.

The content of halogen atoms in the polyimide resin is based on the mass of the polyimide resin, preferably 1 to 40% by mass, more preferably 5 to 40% by mass, and more preferably 5% by mass. to 30% by mass. If the content of the halogen atoms is more than the above lower limit, the tensile modulus of the polyimide resin film and the optical laminate can be further increased, the YI value can be further reduced, and the transparency and visibility can be further improved. Synthesis|combination becomes easy as content of a halogen atom is below the said upper limit.

In another preferred embodiment of the present invention, since the glass transition temperature tends to decrease if silicon atoms are contained, the content of silicon atoms contained in the polyimide resin is preferably less. The content of silicon atoms contained in the polyimide-based resin is based on the mass of the polyimide-based resin, preferably not more than 5% by mass, more preferably not more than 3% by mass, and more preferably not more than 1% by mass. Still more preferably, it is at most 0.5% by mass. It is particularly preferable that the polyimide-based resin does not substantially contain a silicon atom.

The imidization rate of the polyimide resin is preferably at least 90%, more preferably at least 93%, and still more preferably at least 96%. From the viewpoint of improving the optical characteristics of the polyimide-based resin film and the optical laminate easily, the imidization rate is preferably not less than the above-mentioned lower limit. Also, the upper limit of the imidization ratio is 100% or less. The imidization rate means that the molar amount of the imide bond in the polyimide-based resin is twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide-based resin value ratio. Also, when the polyimide-based resin contains a tricarboxylic acid compound, it means that the molar amount of the imide bond in the polyimide-based resin is derived from the tetracarboxylic acid compound in the polyimide-based resin. The ratio of the double value of the molar amount of the structural unit derived from the tricarboxylic acid compound to the total of the molar amount of the structural unit derived from the tricarboxylic acid compound. Also, the imidization ratio can be determined by an IR method, an NMR method, or the like.

The yield stress of the polyimide-based resin film contained as the substrate layer in the optical laminate of the present invention is preferably 200 MPa or more, more preferably 210 MPa or more, and more preferably 220 MPa at a tensile speed of 0.1 m/sec. Above, more preferably above 230MPa, still more preferably above 240MPa. When the yield stress of the polyimide resin film does not reach the above-mentioned lower limit, when stress is applied, the functional layer and the optical layered body are easily deformed due to a large strain, and are easily damaged due to external contact through the functional layer. Depressions are created and remain on the surface. When the yield stress of the polyimide-based resin film is equal to or greater than the above-mentioned lower limit, it is easy to reduce the dents generated on the surface due to contact with external factors, and it is also easy to improve the recovery of the generated dents. From the viewpoint of making it easier to improve the folding resistance of the optical laminate, the polyimide resin film has a yield stress of preferably 400 MPa or less, more preferably 300 MPa or less, at a tensile speed of 0.1 m/sec. The above-mentioned yield stress is the value obtained from the stress-strain curve obtained by the tensile test of ASTM D638-14 when the tensile speed is 0.1m/second with the polyimide resin film as the measurement sample, for example, it can be Measured using the method described in the examples.

The thickness of the polyimide resin film is preferably at least 5 μm, more preferably at least 10 μm, more preferably at least 20 μm, still more preferably at least 25 μm, particularly preferably at least 30 μm, and particularly preferably at least 40 μm. It is preferably at least 45 μm, more preferably at most 200 μm, more preferably at most 100 μm, even more preferably at most 80 μm, particularly preferably at most 60 μm, and may be a combination of these upper and lower limits. When the thickness of the polyimide resin film is within the above range, it is easy to adjust the yield stress of the optical layered body within the above range, and it is easy to reduce the sinking of the optical layered body.

From the viewpoint of easily obtaining the above-mentioned characteristics of the optical layered body, the tensile elastic modulus and folding resistance of the polyimide-based resin film contained as the base material layer in the optical layered body of the present invention The frequency, YI value, total light transmittance and haze are preferably within the preferred ranges described above for the optical laminate of the present invention.

Polyimide resins and polyimide precursor resins can be produced, for example, using tetracarboxylic acid compounds and diamine compounds as main raw materials, and polyamide imide resins and polyamide imide precursor resins can be, for example, Tetracarboxylic acid compounds, dicarboxylic acid compounds, and diamine compounds are produced as main raw materials.

The tetracarboxylic acid compound used in the production of the polyimide resin preferably contains at least the compound represented by formula (X). It is more preferable to further include a compound represented by formula (Y).

[In formula (X), R ¹ to R ⁵ , n and m are the same as R ¹ to R ⁵ , n and m in formula (3) respectively]

[In formula (Y), B, R ⁷ and t are the same as B, R ⁷ and t in formula (5) respectively].

The compound represented by formula (X) can be obtained by a conventional method, for example, by reacting trimellitic anhydride or a derivative thereof with an aromatic diol, and a commercially available product can also be used.

The structural units represented by formula (1) and formula (30) are generally derived from diamine compounds and tetracarboxylic acid compounds. The structural unit represented by formula (31) is usually derived from a diamine compound and a tricarboxylic acid compound.

Examples of the tetracarboxylic acid compound used in the synthesis of the polyimide resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. A tetracarboxylic acid compound can be used individually or in combination of 2 or more types. As the tetracarboxylic acid compound, other than dianhydrides, tetracarboxylic acid compound analogues such as acyl chlorides may be used.

Aromatic tetracarboxylic acid compounds, such as aromatic tetracarboxylic dianhydrides; Aliphatic tetracarboxylic acid compounds, such as aliphatic tetracarboxylic dianhydrides, etc. are mentioned as a tetracarboxylic-acid compound used for resin manufacture. A tetracarboxylic acid compound can be used individually or in combination of 2 or more types. As the tetracarboxylic acid compound, other than dianhydrides, tetracarboxylic acid compound analogues such as acyl chlorides may be used.

Specific examples of aromatic tetracarboxylic dianhydrides include non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic tetracarboxylic dianhydrides. anhydride. Non-condensed polycyclic aromatic tetracarboxylic dianhydrides include 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenylketone tetracarboxylic dianhydride , 2,2',3,3'-diphenyl ketone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride (hereinafter referred to as BPDA), 2,2' ,3,3'-Biphenyltetracarboxylic dianhydride, 3,3',4,4'-Diphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl) Propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'- (Hexafluoroisopropylidene) diphthalic dianhydride (hereinafter referred to as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2, 3-Dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethanedianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride anhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(terephenylene dioxy)diphthalic acid Dianhydride, 4,4'-(m-phenylenedioxy)diphthalic dianhydride. Also, the monocyclic aromatic tetracarboxylic dianhydride can be exemplified by 1,2,4,5-benzenetetracarboxylic dianhydride, and the condensed polycyclic aromatic tetracarboxylic dianhydride can be exemplified by 2,3, 6,7-Naphthalene tetracarboxylic dianhydride.

Among these, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 2,2', 3,3'-Diphenylketonetetracarboxylic dianhydride, BPDA, 2,2',3,3'-Biphenyltetracarboxylic dianhydride, 3,3',4,4'-Diphenylphenone Tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis( 3,4-dicarboxyphenoxyphenyl)propane dianhydride, 6FDA, 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxy Phenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethanedianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride, bis( 3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylene dioxy)diphthalic dianhydride and 4 ,4'-(m-phenylenedioxy)diphthalic dianhydride; more preferably 4,4'-oxydiphthalic dianhydride, BPDA, 2,2',3, 3'-Biphenyltetracarboxylic dianhydride, 6FDA, bis(3,4-dicarboxyphenyl)methane dianhydride and 4,4'-(terephenylene dioxy)diphthalic dianhydride. These can be used individually or in combination of 2 or more types.

Cyclic or acyclic aliphatic tetracarboxylic dianhydrides are mentioned as aliphatic tetracarboxylic dianhydride. Cycloaliphatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride with alicyclic hydrocarbon structure. Specific examples include: 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1, 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, etc. cycloalkanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7- Alkene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, and positional isomers thereof. These can be used individually or in combination of 2 or more types. Specific examples of acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentane tetracarboxylic dianhydride, and the like. These can be used individually or in combination of 2 or more types. Moreover, a cycloaliphatic tetracarboxylic dianhydride and a noncyclic aliphatic tetracarboxylic dianhydride can also be used together.

Among the above-mentioned tetracarboxylic dianhydrides, polyimide-based resin films and optical laminates have high impact resistance, high tensile elastic modulus, high surface hardness, high transparency, high flexibility, and high bending resistance. From the viewpoint of flexibility and low coloring property, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, BPDA are preferable , 2,2',3,3'-biphenyl tetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4- Dicarboxyphenyl) propane dianhydride, 6FDA, and a mixture thereof, more preferably BPDA and 6FDA, and a mixture thereof, and more preferably 6FDA and BPDA.

Examples of diamine compounds used in the production of resins include aliphatic diamines, aromatic diamines, and mixtures thereof. Moreover, "aromatic diamine" in this embodiment means the diamine whose amine group is directly bonded to the aromatic ring, and may contain an aliphatic group or other substituents in a part of its structure. The aromatic ring may be a single ring or a condensed ring, such as benzene ring, naphthalene ring, anthracene ring, and oxene ring, but not limited thereto. Among these, a benzene ring is preferable. Also, "aliphatic diamine" means a diamine in which an amine group is directly bonded to an aliphatic group, and may contain an aromatic ring or other substituents in part of its structure.

Aliphatic diamines include, for example, acyclic aliphatic diamines such as hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, Cycloaliphatic diamines such as hexane, norbornane diamine, and 4,4'-diaminodicyclohexylmethane, etc. These can be used individually or in combination of 2 or more types.

Aromatic diamines include, for example, p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylenediamine, p-xylenediamine, 1,5-diaminonaphthalene, 2,6- Aromatic diamines having one aromatic ring such as diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-di Aminodiphenylphenoxide, 3,3'-diaminodiphenylphenoxide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy) Benzene, bis[4-(4-aminophenoxy)phenyl]pyridine, bis[4-(3-aminophenoxy)phenyl]pyridine, 2,2-bis[4-(4-amine phenoxy)phenyl]propane, 2,2-bis [4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobis Phenyl (also recorded as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl) fluorine, 9,9-bis(4- Amino-3-methylphenyl) fluorine, 9,9-bis(4-amino-3-chlorophenyl) fluorine, 9,9-bis(4-amino-3-fluorophenyl) fluorine, etc. Aromatic diamines having two or more aromatic rings. These can be used individually or in combination of 2 or more types.

Aromatic diamines are preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylether, 3,3' -Diaminodiphenylether, 4,4'-diaminodiphenylene, 3,3'-diaminodiphenylene, 1,4-bis(4-aminophenoxy)benzene , bis[4-(4-aminophenoxy)phenyl]pyridine, bis[4-(3-aminophenoxy)phenyl]pyridine, 2,2-bis[4-(4-amino phenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, TFMB, 4,4'-bis (4-aminophenoxy)biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminobis Phenyl ether, 4,4'-diaminodiphenylphenylene, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]pyridine , 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, TFMB, 4,4'-bis(4-aminophenoxy ) Biphenyl. These can be used individually or in combination of 2 or more types.

Among the above-mentioned diamine compounds, it is preferable to use a polyimide resin film having a high modulus of elasticity, high transparency, high flexibility, high bending resistance, and low coloring properties. One or more types of the group consisting of aromatic diamines having a biphenyl structure. It is more preferable to use a compound selected from TFMB, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)bis One or more types from the group consisting of benzene and 4,4'-diaminodiphenyl ether, and it is more preferable to use TFMB.

The dicarboxylic acid compound used in the production of the resin is preferably terephthalic acid, isophthalic acid, 4,4'-oxydibenzoic acid or their acyl chlorides.

In addition to the use of terephthalic acid, isophthalic acid, 4,4'-oxydibenzoic acid or the acyl chlorides thereof, other dicarboxylic acid compounds may also be used. Examples of other dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their similar acyl chlorides, acid anhydrides, and the like, and two or more of them may be used in combination. Specific examples include isophthalic acid; naphthalene dicarboxylic acid; 4,4'-biphenyl dicarboxylic acid; 3,3'-biphenyl dicarboxylic acid; Acid compounds and two benzoic acid compounds connected by a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or phenylene, and such Acyl chloride. Specific examples are preferably 4,4'-oxybis(benzoyl chloride) (hereinafter also referred to as OBBC), terephthalyl chloride (hereinafter also referred to as TPC) or isophthalyl chloride Hydrochloride, more preferably a combination of OBBC and TPC.

In addition, the above-mentioned polyimide-based resin may be mixed with tetracarboxylic acid, tricarboxylic acid, and anhydrides thereof in addition to the above-mentioned tetracarboxylic acid compound within a range that does not impair various physical properties of the polyimide-based resin film. And derivatives further responders.

As tetracarboxylic acid, the water adduct of the anhydride of the said tetracarboxylic-acid compound is mentioned.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and acyl chlorides and acid anhydrides similar to these, and two or more of them may be used in combination. Specific examples include 1,2,4-benzenetricarboxylic anhydride; 1,3,5-benzenetricarboxylic anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; Diformic anhydride and benzoic acid are linked by a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, or a phenylene group.

When producing a resin, the usage-amount of a diamine compound, a tetracarboxylic-acid compound, and/or a dicarboxylic-acid compound can be suitably selected according to the ratio of each structural unit of polyimide-type resin to be desired.

When producing resin, the reaction temperature of diamine compound, tetracarboxylic acid compound and dicarboxylic acid compound is not particularly limited, for example, it is 5 to 350°C, preferably 20 to 200°C, more preferably 25 to 100°C. The reaction time is also not particularly limited, for example, it is about 30 minutes to 10 hours. The reaction can be carried out in an inert environment or under reduced pressure as needed. In a preferred aspect, the reaction is carried out under normal pressure and/or inert gas environment while stirring. Also, the reaction is preferably carried out in a solvent that is inactive to the reaction. The solvent is not particularly limited as long as it does not affect the reaction, and examples thereof include water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2- Alcohol solvents such as propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone (hereinafter referred to as GBL), γ-valerolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone and other ketones aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; alicyclic hydrocarbon solvents such as ethyl cyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; tetrahydrofuran and dimethoxy Ether-based solvents such as ethyl ethane; chlorine-containing solvents such as chloroform and chlorobenzene; N,N-dimethylacetamide (hereinafter referred to as DMAc), N,N-dimethylformamide (hereinafter referred to as DMF) Amide-based solvents such as amide; sulfur-containing solvents such as dimethylsulfide, dimethylsulfoxide, and cyclobutylene; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof, that is, mixed solvent etc. Among these, amide-based solvents are suitably used from the viewpoint of solubility.

The imidization step in the production of polyimide-based resins can be carried out in the presence of an imidization catalyst. The imidization catalyst can exemplify aliphatic amines such as tripropylamine, dibutylpropylamine, ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, N-butylpyrrolidine, N- Alicyclic amines (monocyclic) such as butylpiperidine and N-propylhexahydroazepine; azabicyclo[2.2.1]heptane, azabicyclo[3.2.1]octane, azabicyclo[ 2.2.2] Octane and azabicyclo[3.2.2]nonane and other alicyclic amines (polycyclic); and pyridine, 2-picoline (2-picoline), 3-picoline (3-picoline), 4-picoline (4-picoline), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-lutidine, 2,4,6-collidine, 3,4-cyclopentenylpyridine, 5,6 ,7,8-tetrahydroisoquinoline and isoquinoline and other aromatic amines. Moreover, from the viewpoint of facilitating the imidization reaction, it is preferable to use an imidization catalyst and an acid anhydride in combination. Examples of acid anhydrides include those commonly used in imidization reactions, and specific examples thereof include aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic acid anhydrides such as phthalic acid.

Polyimide-based resins can be separated, purified and isolated by conventional methods, such as separation means such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography, or a combination of these separation means. In a preferred mode, a large amount of alcohol such as methanol is added to a reaction liquid containing a transparent polyimide-based resin to precipitate the resin, followed by concentration, filtration, drying, etc., thereby isolating.

The polyimide-based resin film may contain at least one kind of filler in addition to the polyimide-based resin. Examples of fillers include organic particles and inorganic particles, preferably inorganic particles. Examples of inorganic particles include metal oxide particles such as silicon dioxide, zirconia, aluminum oxide, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide; Metal fluoride particles such as magnesium chloride and sodium fluoride, etc. Among them, silicon dioxide is preferable from the viewpoint of easiness of increasing the tensile modulus of the polyimide resin film and the optical laminate. Particles, zirconia particles, alumina particles, more preferably silica particles. These fillers can be used individually or in combination of 2 or more types.

The average primary particle size of the filler (preferably silica particles) is usually above 1nm, preferably above 5nm, more preferably above 10nm, more preferably above 11nm, particularly preferably above 13nm, preferably below 100nm , more preferably below 90nm, more preferably below 80nm The thickness is more preferably below 70nm, most preferably below 60nm, particularly preferably below 50nm, and most preferably below 40nm. If the average primary particle diameter of the filler (preferably silica particles) is within the above range, the aggregation of the filler (preferably silica particles) can be suppressed, and the resulting polyimide resin film and optical laminate can be easily improved. Optical properties of the body. The average primary particle size of the filler can be measured by the BET method. Moreover, the average primary particle diameter can also be measured by the image analysis of a transmission electron microscope TEM or a scanning electron microscope SEM.

When the polyimide resin film contains a filler (preferably containing silica particles), the content of the filler is usually 0.1 part by mass or more, preferably 1 part by mass relative to 100 parts by mass of the polyimide resin film Above, more preferably at least 5 parts by mass, more preferably at least 10 parts by mass, still more preferably at least 20 parts by mass, particularly preferably at least 30 parts by mass, more preferably at most 60 parts by mass. When content of a filler is more than the said minimum, it will become easy to raise the tensile elastic modulus of the obtained polyimide-type resin film. Moreover, when content of a filler is below the said upper limit, the optical characteristic of a polyimide-type resin film will improve easily.

The polyimide resin film may further contain an ultraviolet absorber. The ultraviolet absorber can be appropriately selected from those generally used as an ultraviolet absorber in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light having a wavelength of 400 nm or less. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazine-based compounds. The ultraviolet absorbent can be used alone or in combination of two or more. Since the polyimide-based resin film contains an ultraviolet absorber, deterioration of the resin can be suppressed, so that the visibility of the obtained optical laminate can be improved when it is applied to an image display device or the like. In this specification, a "series compound" refers to a derivative of the compound indicated by the "series compound". For example, "benzophenone-based compound" refers to a compound having benzophenone as a main skeleton and a substituent bonded to benzophenone.

When the polyimide resin film contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably at least 1 part by mass, more preferably at least 2 parts by mass, and still more preferably at least 100 parts by mass of the polyimide resin film. It is 3 mass parts or more, Preferably it is 10 mass parts or less, More preferably, it is 8 mass parts or less, More preferably, it is 6 mass parts or less. The suitable content will vary depending on the UV absorber used, but if the content of the UV absorber is adjusted so that the light transmittance at 400nm becomes about 20 to 60%, the light resistance of the polyimide resin film can be improved and easily improve transparency.

The polyimide resin film may further contain fillers and other additives other than the ultraviolet absorber. Other additives include antioxidants, release agents, stabilizers, blueing agents, flame retardants, pH regulators, silica dispersants, lubricants, tackifiers, and leveling agents. When other additives are contained, the content of other additives is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, and more preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the polyimide resin film. .

[Manufacturing method of polyimide-based resin film]

The manufacturing method of the polyimide-type resin film of this invention is not specifically limited, For example, it may be the manufacturing method including the following steps at least.

(a) The varnish preparation step is to prepare a resin composition (hereinafter referred to as "varnish") comprising at least the aforementioned polyimide-based resin and a solvent;

(b) a coating step, which is to apply the varnish to the support material and form a coating film; and

(c) The step of forming a polyimide-based resin film is to dry the aforementioned coating film to form a polyimide-based resin film.

In the varnish preparation step, a polyimide-based resin is dissolved in a solvent, and additives such as the aforementioned fillers and ultraviolet absorbers are added as necessary and stirred and mixed to prepare a varnish. Also, when silica particles are used as the filler, the dispersion liquid of silica sol containing silica particles may be replaced with a solvent capable of dissolving the aforementioned resin, for example, a solvent used for the following varnish preparation, and the aforementioned solvent-substituted The silica sol is added to the resin.

The solvent used for preparing the varnish is not particularly limited as long as it can dissolve the aforementioned resin. The solvent can be, for example, amide-based solvents such as DMAc and DMF; lactone-based solvents such as GBL and γ-valerolactone; sulfur-containing solvents such as dimethylsulfide, dimethylsulfoxide, and cyclobutylene; Carbonate-based solvents such as esters and propylene carbonate; and combinations thereof. Among these, amide-based solvents or lactone-based solvents are preferable. These solvents can be used individually or in combination of 2 or more types. In addition, the varnish may contain water, alcohol-based solvents, ketone-based solvents, acyclic ester-based solvents, ether-based solvents, and the like. The solid content concentration of the varnish is preferably from 1 to 25% by mass, more preferably from 5 to 20% by mass, and still more preferably from 5 to 15% by mass.

In the coating step, a varnish can be applied on the support by a known coating method to form a coating film. Known coating methods include, for example, roll coating methods such as wire bar coating, reverse coating, and gravure coating, die coating, chipped wheel coating, lip coating, spin coating, Screen coating method, fountain coating method, dipping method, spray method, tape casting method, etc.

In the film forming step, the coating film is dried and peeled off from the support to form a polyimide-based resin film. After peeling, a step of drying the polyimide-based resin film may be further provided. Drying of the coating film can usually be carried out at a temperature of 50 to 350°C. Inactive environment or reduced pressure as needed Dry the coating film under these conditions. In addition, a part of the solvent contained in the varnish may remain slightly in the obtained polyimide-based resin film. Relative to the mass of the polyimide resin film, the amount of solvent contained in the polyimide resin film is preferably at most 1.5%, more preferably at most 1.2%, still more preferably at most 1.1%, still more preferably 1.0% or less. The lower limit of the amount of solvent is preferably at least 0%, more preferably at least 0.02%, more preferably at least 0.1%, and still more preferably at least 0.3%.

Examples of support materials include SUS plates for metal-based materials, PET films, PEN films, polyamide-based resin films, other polyimide-based resin films, cycloolefin-based polymer films, and resin-based materials. Acrylic film, etc. Among them, from the viewpoint of excellent smoothness and heat resistance, PET films, cycloolefin-based polymer films, etc. are preferred, and furthermore, from the viewpoint of adhesion to polyimide-based resin films and cost Preferably PET film.

〔Functional layer〕

The optical layering system of the present invention includes the above-mentioned substrate layer made of polyimide resin film, and a functional layer made of cured resin. The functional layer including the cured product of curable resin includes, for example, a hard coat layer, an ultraviolet absorbing layer, a primer layer, a gas barrier layer, an adhesive layer, a hue adjustment layer, a refractive index adjustment layer, and the like. The optical laminate of the present invention may have one or more types of functional layers. The functional layer comprising a cured product of a curable resin is preferably a hard coat layer.

When the optical laminate of the present invention has a hard coat layer as a functional layer of a cured product comprising a curable resin, the thickness of the hard coat layer is not particularly limited, but is preferably 2 to 100 μm, more preferably 3 to 50 μm, and still more preferably 4 to 30 μm. If the thickness of the hard coat layer is within the above-mentioned range, the impact resistance can be further improved, and the bending resistance tends to be less likely to be lowered, and the problem of curling caused by curing shrinkage tends to be less likely to occur. The hard coat layer can be formed by hardening a hard coat composition containing a reactive material capable of forming a crosslinked structure by irradiating active energy rays or applying heat energy, preferably By irradiating active energy rays. Active energy rays are defined as energy rays that can decompose compounds that generate active species and generate active species, such as visible light, ultraviolet rays, infrared rays, X-rays, alpha rays, beta rays, gamma rays, and electron rays, etc., preferably Take ultraviolet light. The aforementioned hard coat composition is a polymer containing at least one kind of radically polymerizable compound and cationic polymerizable compound.

The aforementioned radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group contained in the above-mentioned radical polymerizable compound may be any functional group as long as it can cause a radical polymerization reaction, such as a group containing a carbon-carbon unsaturated double bond, etc., specifically, A vinyl group, a (meth)acryl group etc. are mentioned. Moreover, when the said radically polymerizable compound has 2 or more radically polymerizable groups, these radically polymerizable groups may be the same or different, respectively. From the viewpoint of increasing the hardness of the hard coat layer, the number of radical polymerizable groups that the radical polymerizable compound has in 1 molecule is preferably 2 or more. From the viewpoint of high reactivity, the aforementioned radically polymerizable compound preferably includes a compound having a (meth)acryl group, specifically, a compound having 2 to 6 (methyl) groups in one molecule. Acryl-based compounds called polyfunctional acrylate monomers, or epoxy (meth)acrylates, amine (meth)acrylates, polyester (meth)acrylates with The molecular weight of several (meth)acryl groups is several hundred to several thousand oligomers, preferably can be enumerated and be selected from (meth) acrylate epoxy ester, (meth) acrylate amine ester and polyester ( One or more types of meth)acrylates.

The aforementioned cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, or a vinyl ether group. From the viewpoint of increasing the hardness of the hard coat layer, the number of cationically polymerizable groups in one molecule of the above-mentioned cationically polymerizable compound is preferably 2 or more, more preferably 3 or more.

Moreover, among the aforementioned cationically polymerizable compounds, a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group is preferable. A cyclic ether group such as an epoxy group or an oxetanyl group is preferable in that the shrinkage accompanying the polymerization reaction is small. In addition, the compound having the epoxy group in the cyclic ether group has the advantages of being easy to obtain compounds of various structures, does not adversely affect the durability of the obtained hard coat layer, and is easy to control the compatibility with the radical polymerizable compound. . In addition, among the cyclic ether groups, the oxetane group is easier to increase the degree of polymerization and has low toxicity compared with the epoxy group, and the network formation speed obtained from the cationic polymerizable compound of the obtained hard coat layer is relatively fast. , Even in the area where it is mixed with the radical polymerizable compound, unreacted monomers will not remain in the film, and an independent network will be formed.

The cationically polymerizable compound having an epoxy group can be, for example, prepared by mixing polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or a cyclohexene ring, or a compound containing a cyclopentene ring with hydrogen peroxide, peroxide, etc. Cycloaliphatic epoxy resin obtained by epoxidizing an appropriate oxidizing agent such as an acid; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long-chain polybasic acid Aliphatic epoxy resins such as homopolymers and copolymers of glycidyl (meth)acrylate; bisphenols such as bisphenol A, bisphenol F or hydrogenated bisphenol A or their alkylene oxide adducts Glycidyl ethers produced by the reaction of derivatives such as caprolactone adducts with epichlorohydrin, and glycidyl ether-type epoxy resins derived from bisphenols such as novolac epoxy resins, etc.

The aforementioned hard coat composition may further contain a polymerization initiator. Examples of the polymerization initiator include radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, and the like, which can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby performing radical polymerization and cationic polymerization.

The radical polymerization initiator should only be a substance capable of releasing radical polymerization by at least one of active energy ray irradiation and heating. Examples of thermal radical polymerization initiators include organic peroxides such as hydrogen peroxide and benzoic acid peroxide, azo compounds such as azobisbutyronitrile, and the like.

The active energy ray radical polymerization initiator is a type I radical polymerization initiator that generates free radicals by molecular decomposition, and a type II free radical that coexists with a tertiary amine and undergoes a dehydrogenation reaction to generate free radicals A polymerization initiator, these can be used individually or in combination.

The cationic polymerization initiator should only be a substance capable of releasing cationic polymerization by at least one of active energy ray irradiation and heating. As a cationic polymerization initiator, an aromatic iodonium salt, an aromatic percite salt, a ferrocene (II) complex, etc. can be used. Due to structural differences, these can initiate cationic polymerization by either or both of active energy ray irradiation or heating.

The polymerization initiator may preferably be contained in an amount of 0.1 to 10% by mass relative to 100% by mass of the entire hard coat composition. If the content of the above-mentioned polymerization initiator is within the above-mentioned range, the hardening can be performed sufficiently, and the mechanical properties and adhesive force of the finally obtained coating film can be in a good range, and it becomes difficult to cause poor adhesion due to hardening shrinkage. Or the tendency of cracking phenomenon and curling phenomenon.

The aforementioned hard coat composition may further contain one or more members selected from the group consisting of solvents and additives.

The aforementioned solvent can be used as long as it can dissolve or disperse the aforementioned polymerizable compound and polymerization initiator, and is a solvent known as a solvent for hard coat compositions in this technical field, within the range that does not inhibit the effect of the present invention.

The aforementioned additives may further contain inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

The hard coat layer is formed by irradiating the coating film with high-energy rays such as active energy rays to harden the coating film, for example, in a hard coat layer in a functional layer made of a cured product of a curable resin. The irradiation intensity can be appropriately determined according to the composition of the curable composition, and is not particularly limited, but irradiation is preferably in a wavelength range effective for activating the polymerization initiator. The irradiation intensity is preferably from 0.1 to 6,000 mW/cm ² , more preferably from 10 to 1,000 mW/cm ² , and still more preferably from 20 to 500 mW/cm ² . If the irradiation intensity is within the above range, an appropriate reaction time can be ensured, and yellowing or deterioration of the resin due to heat radiated from the light source and heat generated during curing reaction can be suppressed. The irradiation time can be appropriately selected according to the composition of the curable composition, and there is no particular limitation, but the cumulative light amount shown by the product of the aforementioned irradiation intensity and irradiation time is preferably 10 to 10,000 mJ/cm ² , more preferably 50 to 1,000mJ/cm ² , and more preferably 80 to 500mJ/cm ² . When the accumulated light amount is within the above range, a sufficient amount of active species derived from the polymerization initiator can be generated, and the hardening reaction can proceed more reliably. Moreover, the irradiation time is not too long, and good productivity can be maintained. Also, the irradiation step in this range is beneficial to further increase the hardness of the hard coat layer.

From the viewpoint of improving the smoothness of the hard coat layer and further improving the visibility in the wide-angle direction of the optical film, optimization of the type of solvent, component ratio, solid content concentration, addition of a leveling agent, and the like are mentioned.

The ultraviolet absorbing layer is a layer having the function of absorbing ultraviolet rays, and is formed, for example, of a main material selected from ultraviolet curable transparent resin, electron beam curable transparent resin, and thermosetting transparent resin, and an ultraviolet absorber dispersed in the main material. constitute.

The adhesive layer is a layer having an adhesive function, and has the function of adhering the polyimide resin film to other members. A generally known material can be used for the formation material of an adhesive layer. For example, you can use A thermosetting resin composition or a photosetting resin composition is used. At this time, the resin composition can be polymerized and cured by supplying energy afterwards.

The adhesive layer may be a layer called a pressure sensitive adhesive (also referred to as PSA) that is attached to an object by pressing. The pressure-sensitive adhesive can also be an adhesive that belongs to the "substance that has adhesiveness at room temperature and adheres to the substrate with light pressure" (JIS K 6800), or it can be "a specific component is loaded on the protective film (micro Capsule) and can maintain stability until the film is destroyed by appropriate means such as pressure or heat" (JIS K 6800 regulations) capsule-type adhesives.

The hue adjustment layer is a layer having a hue adjustment function, and is a layer capable of adjusting a laminate including a polyimide-based resin film to a desired hue. The hue adjustment layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, red iron oxide, titanium oxide-based fired pigments, ultramarine blue, cobalt aluminate, and carbon black; azo compounds, quinacridone-based compounds, anthraquinone-based Organic pigments such as compounds, perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinolinone compounds, threne compounds, and diketopyrrolopyrrole compounds; barium sulfate and calcium carbonate and other body pigments; and dyes such as basic dyes, acid dyes, and mordant dyes.

The refractive index adjustment layer is a layer having a refractive index adjustment function, for example, a layer that has a different refractive index from the polyimide resin film and can impart a specific refractive index to the optical laminate. The refractive index adjustment layer may be, for example, a resin layer containing an appropriately selected resin and, if necessary, a pigment, or a metal thin film. Pigments for adjusting the refractive index include, for example, 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 keeping the average primary particle size of the pigment below 0.1 μm, it is possible to prevent penetration refraction The diffuse reflection of the light in the rate adjustment layer prevents loss of transparency. Metals used in the refractive index adjustment 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 metal nitrides.

In a preferred embodiment of the present invention, the optical laminate of the present invention can be used as a front panel of an image display device, especially as a front panel of a flexible display device (hereinafter referred to as a window film (window film)), The front panel of a rollable display or a foldable display. A flexible display device includes, for example, a flexible functional layer and an optical laminate that is laminated on the flexible functional layer and functions as a front panel. That is, the front panel of the flexible display device is disposed on the viewing side of the flexible functional layer. The front panel has the function of protecting the flexible functional layer, for example, the function of protecting the image display elements in the flexible display. Also, a flexible display device refers to a display device that is used by performing operations such as repeated bending and repeated winding of an image display device. High bending resistance is required for the front panel of the flexible display device used for such repeated bending operations. Also, high visibility is required for the front panel. Compared with the substrate film of the image display device used inside the image display device, the front panel of the image display device, especially the film system for the front panel of the flexible display device requires high visibility and high bending resistance. For example, from the point of view of improving the visibility when used as a front panel of a flexible display device, the film of the present invention preferably has the above-mentioned total light transmittance, haze and/or YI value, and is represented by From the viewpoint of easily improving the bending resistance when used as a front panel of a flexible display device, the film of the present invention preferably satisfies the number of times of bending resistance in the MIT folding fatigue test described above.

Examples of image display devices include TVs, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, indicators (indicators), message boards, clocks, and Wearable devices such as smart watches, etc. The flexible display device can include all image display devices with flexible properties, such as the above-mentioned roll-up display or foldable display. A roll-up display refers to an image display device in which the image display part including the front panel is rolled into a roll shape and the image display part is pulled out and used in a flat or curved state. It must be rolled up into a roll shape every time it is used. Image display devices for other operations. In addition, a foldable display refers to an image display device in which the image display part including the front panel is bent, and the image display part is opened to be used in a flat or curved state, and operations such as bending are required for each use. Image display device. An image display device that repeatedly performs operations such as rolling and bending is called a flexible image display device.

[Flexible display device]

The present invention also provides a flexible display device having the optical laminate of the present invention. The optical laminate of the present invention is preferably used as a front plate in a flexible display device. The flexible display device is composed of a laminate for a flexible display device and an organic EL display panel. The laminate for a flexible display device is arranged on the viewing side of the organic EL display panel in a bendable manner. The laminate for flexible display devices may contain the window film, polarizer, and touch sensor of the optical laminate of the present invention, and the lamination order of these is arbitrary, but it is preferable to laminate the window film sequentially from the viewing side , polarizer, touch sensor or window film, touch sensor, polarizer. If there is a polarizing plate on the viewing side of the touch sensor, it becomes difficult to recognize the pattern of the touch sensor, and the visibility of the displayed image becomes better, which is preferable. Separate members can be laminated using an adhesive, an adhesive, or the like. In addition, it may be provided with a light-shielding pattern formed on at least one surface of any layer of a window film, a polarizing plate, or a touch sensor.

[polarizer]

The flexible display device of the present invention may further include a polarizing plate, preferably a circular polarizing plate. Circular polarizer is laminated with linear polarizer and λ/4 retardation plate, so it has only transmission right The functional layer of the function of the circular polarizing component or the left circular polarizing component. For example, it can be used to convert external light into right circularly polarized light and block the external light reflected as left circularly polarized light on the organic EL panel, and only transmit the luminescent component of organic EL, thereby suppressing the influence of reflected light and making it easier to view images.

In order to achieve the function of circular polarization, the absorption axis of the linear polarizer and the slow axis of the λ/4 phase difference plate need to be 45° in theory, but it is 45±10° in practice. The linear polarizer and the λ/4 retardation plate do not have to be stacked adjacently, as long as the relationship between the absorption axis and the slow axis satisfies the aforementioned range. It is preferable to achieve complete circular polarization at all wavelengths, but this is not necessarily the case in practice, so the circular polarizing plate in the present invention also includes an elliptic circular polarizing plate. A λ/4 retardation film is further laminated on the viewing side of the linear polarizing plate to make the emitted light circularly polarized, thereby improving the visibility when wearing polarized sunglasses.

The linear polarizer is a functional layer that passes light vibrating in the direction of the transmission axis, but blocks polarized light of the vibration component perpendicular to it. The aforementioned linear polarizer may be a linear polarizer alone, or may include a linear polarizer and a protective film bonded to at least one side thereof.

The thickness of the aforementioned linear polarizing plate may be less than 200 μm, preferably 0.5 to 100 μm. When the thickness is within the aforementioned range, it tends to be difficult to reduce flexibility.

The aforementioned linear polarizer may be a film-type polarizer manufactured by dyeing and stretching a polyvinyl alcohol (hereinafter referred to as PVA) film. Polarizing performance can be exhibited by adsorbing dichroic dyes such as iodine on PVA-based films that are oriented by stretching, or by stretching dichroic dyes in the state of being adsorbed on PVA. In the manufacture of the aforementioned film-type polarizer, additional steps such as swelling, crosslinking by boric acid, washing by aqueous solution, and drying may be included. The stretching or dyeing step can be performed in a state where the PVA-based film is alone, or in a state where other films such as polyethylene terephthalate are laminated. The thickness of the PVA-based film used is preferably 10 to 100 μm, and the elongation ratio is preferably 2 to 10 times.

Furthermore, as another example of the aforementioned polarizer, it may be a liquid crystal coated polarizer formed by coating a liquid crystal polarizing composition. The aforementioned liquid crystal polarizing composition may contain a liquid crystal compound and a dichroic dye compound. The above-mentioned liquid crystal compound only needs to have the property of displaying a liquid crystal state, and it is preferable if it has a smectic high-order alignment state because it can exhibit high polarizing performance. Also, the liquid crystal compound preferably has a polymerizable functional group.

The dichroic dye is a dye that aligns with the liquid crystal compound to exhibit dichroism, and the dichroic dye itself may have liquid crystallinity or may have a polymerizable functional group. Any compound in the liquid crystal polarizer composition has a polymerizable functional group.

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

The aforementioned liquid crystal polarizing layer is manufactured by coating a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer.

Compared with film-type polarizers, the liquid crystal polarizer layer can be formed with a thinner thickness. The thickness of the aforementioned liquid crystal polarizing layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.

The aforementioned alignment film can be produced, for example, by applying an alignment film-forming composition on a substrate and imparting alignment by rubbing, irradiating polarized light, or the like. The aforementioned oriented film forming composition may contain a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like in addition to the oriented agent. As the alignment agent, for example, polyvinyl alcohols, polyacrylates, polyamide acids, and polyimides can be used. When photo-alignment is used, it is preferable to use an alignment agent containing cinnamate groups. The weight-average molecular weight of the polymer used as the aforementioned alignment agent may be about 10,000 to 1,000,000. From the viewpoint of orientation confining force, the thickness of the aforementioned orientation film is preferably from 5 to 10,000 nm, more preferably from 10 to 500 nm. The aforementioned liquid crystal polarizing layer may be peeled off from the substrate and transferred to form a laminate, or the aforementioned substrate may be maintained in its original state. state and layered. The aforementioned base material is preferably used as a transparent base material for a protective film, a retardation film, or a window film.

The aforementioned protective film may be a transparent polymer film. Specifically, examples of the polymer film to be used include polyethylene, polypropylene, polymethylpentene, and one having a monomer unit containing norbornene or cycloolefin. Polyolefins such as cycloolefin derivatives, (modified) celluloses such as cellulose diacetate, cellulose triacetate, and acrylic cellulose, acrylics such as methyl methacrylate (co)polymers, styrene ( Co) polymers such as polystyrene, acrylonitrile/butadiene/styrene copolymers, acrylonitrile/styrene copolymers, ethylene/vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride Polyesters such as vinyl, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyarylate, and polyamides such as nylon Classes, polyimides, polyamideimides, polyetherimides, polyetherimides, polyamides, polyvinyl alcohols, polyvinyl acetals, polyurethanes, epoxy resins From the viewpoint of excellent transparency and heat resistance, polyamide, polyamideimide, polyimide, polyester, olefin, acrylic or cellulose-based films are preferred. .

These polymers can be used individually or in mixture of 2 or more types, respectively. The films can be used unstretched, or uniaxially stretched or biaxially stretched films can be used. Preferable are cellulose-based films, olefin-based films, acrylic films, and polyester-based films. It may also be a coating-type protective film obtained by applying a cation-curing composition such as epoxy resin or a radical-curing composition such as acrylate and curing it. If necessary, it may contain plasticizers, ultraviolet absorbers, infrared absorbers, coloring agents such as pigments or dyes, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, smoothing agents, etc. agents, solvents, etc.

The thickness of the aforementioned protective film may be less than 200 μm, preferably 1 to 100 μm. If the thickness of the protective film is within the aforementioned range, the flexibility of the protective film will not be easily reduced.

The aforementioned λ/4 phase difference plate is a film that imparts a phase difference of λ/4 in the direction perpendicular to the traveling direction of incident light (that is, the in-plane direction of the film). The aforementioned λ/4 retardation plate may be an extended retardation plate manufactured by stretching polymer films such as cellulose-based films, olefin-based films, and polycarbonate-based films. If necessary, it may contain phase difference adjusting agent, plasticizer, ultraviolet absorber, infrared absorber, coloring agent such as pigment or dye, fluorescent whitening agent, dispersant, heat stabilizer, light stabilizer, antistatic agent , antioxidants, lubricants, solvents, etc. The thickness of the above-mentioned extended phase difference plate may be less than 200 μm, preferably 1 to 100 μm. When the thickness is within the aforementioned range, the flexibility of the film tends to be less likely to decrease.

Furthermore, another example of the aforementioned λ/4 retardation plate may be a liquid crystal coating type retardation plate formed by coating a liquid crystal composition. The aforementioned liquid crystal composition includes a liquid crystal compound having a property of exhibiting liquid crystal states such as nematic, cholesteric, and smectic. Any compound including a liquid crystal compound in the liquid crystal composition has a polymerizable functional group. The aforementioned liquid crystal coating type retardation plate may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The aforementioned liquid crystal coating type retardation plate can be manufactured by coating a liquid crystal composition on an alignment film and curing it to form a liquid crystal retardation layer, similarly to the aforementioned liquid crystal polarizing layer. Compared with the extended type retardation plate, the liquid crystal coating type retardation plate can be formed with a thinner thickness. The thickness of the aforementioned liquid crystal polarizing layer may generally be 0.5 to 10 μm, preferably 1 to 5 μm. The above-mentioned liquid crystal coating type phase difference plate may be peeled from the substrate and transferred and laminated, or may be laminated with the substrate as it is. The aforementioned base material is preferably used as a transparent base material for a protective film, a retardation film, or a window film.

In general, there are many materials that exhibit larger birefringence with shorter wavelengths and smaller birefringence with longer wavelengths.

At this time, it is impossible to achieve a phase difference of λ/4 in the entire visible light region, so it is mostly designed to become an in-plane phase difference of λ/4 near 560nm, which has a high visual sensitivity, that is, it is 100 to 180nm, relatively It is better to design in the way of 130 to 150nm. It is preferable to use an inverse dispersion λ/4 retardation plate system using a material having a birefringence wavelength dispersion characteristic opposite to that of a normal one, since visibility is good. As far as the material is concerned, in the case of an extended type retardation film, it is preferable to use the one described in Japanese Patent Application Laid-Open No. 2007-232873, etc., and in the case of a liquid crystal coating type retardation film, it is preferable to use Japanese Those described in JP-A-2010-30979.

Also, as another method, a technique for obtaining a wide-range λ/4 retardation plate by combining with a λ/2 retardation plate is known (for example, Japanese Patent Application Laid-Open No. 10-90521). The λ/2 retardation plate can also be produced with the same material and method as the λ/4 retardation plate. The combination of the stretched type retardation film and the liquid crystal coating type retardation film is optional, but it is preferable to use both of the liquid crystal coating type retardation film because the thickness can be made thinner.

Among the aforementioned circular polarizing plates, in order to improve visibility in oblique directions, a method of laminating a positive-C plate is known (for example, JP-A-2014-224837). The positive-C plate can be a liquid crystal coating type phase difference plate, or an extended type phase difference plate. The retardation in the thickness direction is usually -200 to -20 nm, preferably -140 to -40 nm.

[Touch sensor]

The flexible display device of the present invention may further include a touch sensor. A touch sensor is used as an input means. Various types of touch sensors, such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and an electrostatic capacitance method, have been proposed, and any method may be used. That Among them, the electrostatic capacitance method is preferable. The capacitive touch sensor is divided into an active area and an inactive area located outside the active area. The active area is the area where the screen is displayed on the display panel, that is, the area corresponding to the display part, and the area that senses the touch of the user. The inactive area is the area that does not display the screen on the display device, that is, the area corresponding to the non- The display area. The touch sensor may include a flexible substrate; a sensing pattern formed on the active area of the aforementioned substrate; and sensing lines formed on the inactive area of the aforementioned substrate for passing through the sensing pattern and the pad The part is connected with the external drive circuit. The substrate with flexible properties can use the same material as the aforementioned polymer film. In terms of suppressing the cracks of the touch sensor, the substrate of the touch sensor is preferably one whose toughness is above 2,000MPa%. More preferably, the toughness is 2,000 to 30,000MPa%. Here, the toughness is defined as the area under the curve up to the failure point in the stress (MPa)-strain (%) curve (Stress-strain curve) obtained through the tensile test of the polymer material.

The aforementioned sensing pattern may have a first pattern formed in the first direction and a second pattern formed in the second direction. The first pattern and the second pattern can be arranged in different directions from each other. The first pattern and the second pattern are formed on the same layer, and in order to sense the touch points, the respective patterns must be electrically connected. The first pattern is a form in which the unit patterns are connected to each other through contacts, but the second pattern is a structure in which the unit patterns are separated from each other in the form of islands. Therefore, additional bridge electrodes are required to electrically connect the second patterns. Known transparent electrode materials can be used for the sensing pattern. Examples include 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), poly(3,4-ethylenedioxythiophene)], carbon nanotube (CNT), graphene, metal wire, etc., which can be used alone or mixed Use more than 2 types. Preferably, ITO can be used. metal wire The metal used is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium. These can be used individually or in mixture of 2 or more types.

The bridging electrodes can be formed on the upper part of the sensing pattern through the insulating layer, or the bridging electrodes can be formed on the substrate and then the insulating layer and the sensing pattern can be formed thereon. The aforementioned bridging electrodes can be formed of the same material as the sensing pattern, or can be formed of metals such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or alloys of two or more of these. The first pattern and the second pattern must be electrically insulated, so an insulating layer is formed between the sensing pattern and the bridging electrodes. The insulating layer may be formed only between the contacts of the first pattern and the bridging electrodes, or may be formed as a layer structure covering the sensing pattern. In the latter case, the bridging electrodes may be connected to the second pattern through contact holes formed in the insulating layer. The aforementioned touch sensor may further have an optical adjustment layer between the substrate and the electrodes as a means of properly compensating for the difference in transmittance between the patterned area and the non-patterned area where no pattern is formed, specifically In order to properly compensate for the difference in light transmittance caused by the difference in refractive index in these regions, the aforementioned optical adjustment layer may contain an inorganic insulating substance or an organic insulating substance. The optical adjustment layer can be formed by coating a photocurable composition containing a photocurable organic adhesive and a solvent on the substrate. The aforementioned photocurable composition may further contain inorganic particles. The refractive index of the optical adjustment layer can be increased by the aforementioned inorganic particles.

The aforementioned photocurable organic adhesive may contain, for example, copolymers of monomers such as acrylate-based monomers, styrene-based monomers, and carboxylic acid-based monomers. The aforementioned photocurable organic adhesive can be, for example, a copolymer comprising repeating units that are different from each other, such as epoxy group-containing repeating units, acrylate repeating units, and carboxylic acid repeating units.

The aforementioned inorganic particles may contain, for example, zirconia particles, titania particles, alumina particles, and the like. The aforementioned photocurable composition may further contain various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing assistant.

[adhesion layer]

Layers such as window films, polarizers, and touch sensors forming the above-mentioned laminate for flexible display devices, and film components such as linear polarizers and λ/4 retardation plates constituting each layer can be bonded with an adhesive. As the adhesive, water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent-volatile adhesives, moisture-curing adhesives, heat-curing adhesives, anaerobic-curing adhesives, Water-based solvent-volatile adhesives, active energy ray-curable adhesives, hardener-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives, pressure-sensitive adhesives, and remoistening adhesives are widely used . Among them, it is preferable to use a water-based solvent-volatile adhesive, an active energy ray-curable adhesive, and an adhesive. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force, for example, it is 0.01 to 500 μm, preferably 0.1 to 300 μm. Adhesive layer There may be a plurality of layers in the above-mentioned laminate for flexible image display device, and the thickness of each and the type of adhesive used may be the same or different.

The aforementioned water-based solvent-volatile adhesives can use water-dispersed polymers such as polyvinyl alcohol-based polymers, starch and other water-soluble polymers, ethylene/vinyl acetate-based emulsions, and styrene/butadiene-based emulsions as the main agent. polymer. In addition to water and the above-mentioned main ingredient polymer, crosslinking agents, silane compounds, ionic compounds, crosslinking catalysts, antioxidants, dyes, pigments, inorganic fillers, organic solvents, etc. can also be blended. When bonding with the above-mentioned water-based solvent-volatile adhesive, inject the above-mentioned water-based solvent-volatile adhesive between the layers to be bonded, bond the layers, and then dry them to impart adhesiveness. When using the aforementioned water-based solvent volatile adhesive, the adhesive layer The thickness may be 0.01 to 10 μm, preferably 0.1 to 1 μm. When the above-mentioned water-based solvent-volatile adhesive is used to form multiple layers, the thickness of the respective layers and the type of the above-mentioned adhesive may be the same or different.

The aforementioned active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material that is irradiated with active energy rays to form an adhesive layer. The aforementioned active energy ray-curable composition may contain at least one polymer of the same radical polymerizable compound and cation polymerizable compound as the hard coat composition. The aforementioned radically polymerizable compound is the same as the hard coat composition, and the same type as the hard coat composition can be used. The radically polymerizable compound used in the adhesive layer is preferably a compound having an acryl group. In order to reduce the viscosity of the adhesive composition, it is preferable to contain a monofunctional compound.

The aforementioned cationically polymerizable compound is the same as the hard coat composition, and the same type as the hard coat composition can be used. The cationic polymerizable compound used in the active energy ray curing composition is preferably an epoxy compound. In order to reduce the viscosity of the adhesive composition, it is preferable to contain a monofunctional compound as a reactive diluent.

The active energy ray composition may further contain a polymerization initiator. As the polymerization initiator, a radical polymerization initiator, a cationic polymerization initiator, a radical or cationic polymerization initiator and the like can be appropriately selected and used. These polymerization initiators are those that can be decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations and perform radical polymerization and cationic polymerization. In the description of the hard coat composition, an initiator that initiates at least one of radical polymerization or cationic polymerization by irradiating active energy rays can be used.

The aforementioned active energy ray-curable composition may further contain an ion scavenger, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a flow viscosity modifier, Plasticizers, defoamers solvents, additives, solvents. When bonding with the above-mentioned active energy ray-curable adhesive, the above-mentioned active energy ray-curable composition can be applied to either or both of the layers to be bonded, and then bonded, passing through either or both of the layers to be bonded The layer to be bonded is irradiated with active energy rays and hardened, thereby being bonded. When the aforementioned active energy ray-curable adhesive is used, the thickness of the adhesive layer may generally be 0.01 to 20 μm, preferably 0.1 to 10 μm. When the aforementioned active energy ray-curable adhesive is used to form multiple layers, the thickness of each layer and the type of adhesive used may be the same or different.

The above-mentioned adhesive can use any one classified into acrylic adhesives, urethane adhesives, rubber adhesives, silicone adhesives, etc. depending on the polymer of the main agent. In addition to the main polymer, the adhesive can also be blended with cross-linking agents, silane compounds, ionic compounds, cross-linking catalysts, antioxidants, tackifiers, plasticizers, dyes, pigments, inorganic fillers wait. The adhesive composition is obtained by dissolving and dispersing the components constituting the aforementioned adhesive in a solvent, and the adhesive composition is coated on a substrate and dried to form an adhesive layer or an adhesive layer. The adhesive layer may be formed directly, or may be formed by transferring what is separately formed on the base material. It is also preferable to use a release film to cover the adhesive surface before bonding. When the aforementioned adhesive is used, the thickness of the adhesive layer may generally be 1 to 500 μm, preferably 2 to 300 μm. When the aforementioned adhesive is used to form multiple layers, the thickness of each layer and the type of adhesive used may be the same or different.

[shading pattern]

The aforementioned light-shielding pattern can be applied as at least a part of the frame or casing of the aforementioned flexible image display device. The light-shielding pattern can hide the wiring arranged on the edge of the flexible image display device and make it difficult to see, thereby improving the visibility of the image. The aforementioned light-shielding pattern can be in the form of a single layer or multiple layers. The color of the shading pattern is not particularly limited, it can have black, white Color, metallic color and other colors. The light-shielding pattern can be formed by colored pigments and polymers such as acrylic resin, ester resin, epoxy resin, polyurethane, and polysiloxane. These can be used individually or in mixture of 2 or more types. The aforementioned light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light-shielding pattern is usually 1 to 100 μm, preferably 2 to 50 μm. Moreover, it is preferable to give shapes, such as inclination, to the thickness direction of a light-shielding pattern.

(Example)

The present invention will be described in further detail below through examples and comparative examples, but the present invention is not limited to the examples. In addition, "%" and "part" in an Example and a comparative example are "mass %" and "mass part" unless otherwise indicated.

<Measurement of weight average molecular weight>

Gel Permeation Chromatography (GPC) Determination

(1) Pretreatment method

Add DMF eluent (solution with lithium bromide 10mmol/L) to the polyamideimide membrane so that the concentration becomes 2mg/mL, and heat at 80°C while stirring for 30 minutes, and form a 0.45μm film after cooling filter, and use this as the assay solution.

(2) Measurement conditions

Column: TSKgel α-2500 manufactured by TOSOH Co., Ltd. [(7) 7.8 mm diameter × 300 mm) × 1 branch, α-M ((13) 7.8 mm diameter × 300 mm] × 2 branches.

Eluent: DMF (with the addition of 10 mmol/L lithium bromide).

Flow rate: 1.0mL/min.

Detector: RI detector.

Column temperature: 40°C.

Injection volume: 100 μL.

Molecular weight standard: standard polystyrene.

[Manufacturing example 1]

Manufacture of polyamide imide resin (1)

Under a nitrogen atmosphere, 313.6 g of DMAc was added to a 1 L separation flask equipped with stirring fins, and 16.77 g (52.37 mmol) of TFMB was added while stirring at room temperature, and dissolved in DMAc. Then, 4.797 g (10.80 mmol) of 6FDA and 6.679 g (10.80 mmol) of tetracarboxylic dianhydride (TMPBP-TME) represented by the following formula (A) were added to the flask, and stirred at room temperature for 16 hours.

Thereafter, 6.576 g (32.39 mmol) of TPC and 313.6 g of DMAc were added to the flask, and stirred at room temperature for 2 hours. Then, 5.582g (43.19mmol) of N,N-diisopropylethylamine, 7.716g (75.58mmol) of acetic anhydride, and 4.022g (43.19mmol) of 4-picoline were added to the flask, and stirred at room temperature for 30 minutes. The temperature was raised to 70° C. using an oil bath, and further stirred for 3 hours to obtain a reaction liquid. The resulting reaction solution was cooled to room temperature and stirred, and slowly poured into methanol with a mass of 1.385 times the mass of the reaction solution, and then slowly poured into water with a mass of 0.6924 times the mass of the obtained reaction solution. The separated precipitate was taken out and washed with methanol. Then, the precipitate was dried under reduced pressure at 80° C. to obtain a polyamideimide resin (1). Mw of the polyamideimide resin (1) was 360,000.

[Manufacturing example 2]

Manufacture of polyamide imide resin (2)

Under a nitrogen atmosphere, 313.6 g of DMAc was added to a 1 L separation flask equipped with stirring fins, and 17.43 g (54.43 mmol) of TFMB was added while stirring at room temperature, and dissolved in DMAc. Then, 2.493 g (5.610 mmol) of 6FDA and 6.942 g (11.22 mmol) of TMPBP-TME were added to the flask, and stirred at room temperature for 16 hours.

Thereafter, 7.975 g (39.28 mmol) of TPC and 313.6 g of DMAc were added to the flask, and stirred at room temperature for 2 hours. Then, 5.077g (39.28mmol) of N,N-diisopropylethylamine, 12.03g (117.84mmol) of acetic anhydride, and 3.658g (39.28mmol) of 4-picoline were added to the flask, and stirred at room temperature for 30 minutes. The temperature was raised to 70° C. using an oil bath, and further stirred for 3 hours to obtain a reaction liquid. The resulting reaction solution was cooled to room temperature and stirred, and slowly poured into methanol with a mass of 1.385 times the mass of the reaction solution, and then slowly poured into water with a mass of 0.6924 times the mass of the obtained reaction solution. The separated precipitate was taken out and washed with methanol. Then, the precipitate was dried under reduced pressure at 80° C. to obtain a polyamideimide resin (2). The Mw of the polyamideimide resin (2) was 330,000.

[Manufacturing example 3]

Manufacture of polyamide imide resin (3)

Under a nitrogen atmosphere, 313.6 g of DMAc was added to a 1 L separation flask equipped with stirring fins, and 18.36 g (57.33 mmol) of TFMB was added while stirring at room temperature, and dissolved in DMAc. Then the reaction solution was cooled to 10°C. After cooling, 7.718 g (17.37 mol) of 6FDA was added to the flask, maintained at 10° C. and stirred for 16 hours. Thereafter, OBBC 1.709 g (5.791 mmol), TPC 7.054 g (34.75 mmol), and DMAc 313.6 g were added to the flask, and stirred at 10° C. for 2 hours. Then, 5.240 g (40.54 mmol) of N,N-diisopropylethylamine, 12.416 g (121.6 mmol) of acetic anhydride, and 3.775 g (40.54 mmol) of 4-methylpyridine were added to the flask, and stirred at room temperature for 30 minutes. The temperature was raised to 70° C. using an oil bath, and further stirred for 3 hours to obtain a reaction liquid. The resulting reaction solution was cooled to room temperature and stirred Mix, slowly drop into the methanol of 1.385 times of the quality of the reaction solution, then slowly drop into the water of 0.6924 times of the quality of the reaction solution obtained. The separated precipitate was taken out and washed with methanol. Then, the precipitate was dried under reduced pressure at 80° C. to obtain a polyamideimide resin (3). The Mw of the polyamideimide resin (3) was 430,000.

[Manufacturing example 4]

Preparation of silica sol

393.4 g of methanol-dispersed silica sol (manufactured by Nissan Chemical Co., Ltd., MA-ST-G-ML1; average particle size: 27 μm, solid content of silica particles: 30.5% by mass) and 261.0 g of GBL were put into a 2-L flask. Under the hot water bath at 45°C, the vacuum evaporator evaporates methanol at 400hPa for 40 minutes, and at 250Pa for 60 minutes. Also, the temperature was raised to 80° C. at 250 hPa and heated for 30 minutes to obtain GBL-dispersed silica sol 1 .

[Manufacturing example 5]

Preparation of Curable Resin Composition A

19 parts by mass of urethane acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., MIRAMER 620D), 19 parts by mass of polyfunctional acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., MIRAMER SP1106), antimony pentoxide (Toyo Ink ink Co., Ltd., TYS-F90-KR) 20 parts by mass, methyl ethyl ketone (Tokyo Chemical Industry Co., Ltd.) 38 parts by mass, leveling agent (BYK (registered trademark) by BYK JAPAN Co., Ltd. -307) 0.3 parts by mass were stirred and mixed to obtain curable resin composition A.

[Manufacturing example 6]

Preparation of Curable Resin Composition B

9.5 parts by mass of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (manufactured by Daicel Co., Ltd., celloxide 2021P), 3,4-epoxycyclohexylmethyl methacrylate ( Daicel Co., Ltd., cyclomer M100) 18.9 parts by mass, 4-functional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMMT) 18.9 parts by mass, tri-functional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMPT) ) 9.5 parts by mass, acryl-modified silica particles (manufactured by Nissan Chemical Co., Ltd., PGM-2140Y; average primary particle diameter 10 to 15 nm) 40 parts by mass, iodonium (4-methylphenyl) [4-( 2-methylpropyl)phenyl]-hexafluorophosphate and propylene carbonate in a mass ratio of 3:1 mixture (manufactured by BASF JAPAN Co., Ltd., IRGACURE (registered trademark) 250) 1.0 parts by mass, 1-hydroxy - Cyclohexyl-phenyl-ketone (manufactured by BASF JAPAN Co., Ltd., IRGACURE (registered trademark) 184) 2.2 parts by mass, silicone-based leveling agent (manufactured by BYK JAPAN Co., Ltd., BYK (registered trademark)-307) 0.1 parts by mass were stirred and mixed to obtain curable resin composition B.

[Manufacturing example 7]

Manufacture of polyamideimide film (1)

DMAc was added to the polyamideimide resin (1) to prepare a 10.5% by mass polyamideimide varnish (1). The obtained polyamideimide varnish (1) was coated on a smooth surface of a glass substrate using an applicator so that the thickness of the finally obtained film became 50 μm, and dried at 140° C. for 30 minutes to obtain a self-supporting film . The obtained self-supporting film was fixed on a metal frame, and dried at 210° C. for 90 minutes to obtain a polyamideimide film (1) with a thickness of 50 μm.

[Manufacturing example 8]

Manufacture of polyamideimide film (2)

Add DMAc to polyamide imide resin (2) to prepare 8.4% by mass of polyamide imide varnish (2), and obtain polyamide with a thickness of 50 μm in the same manner as in Production Example 7 Imide film (2).

[Manufacturing example 9]

Manufacture of polyamideimide film (3)

Dissolve polyamideimide (1) in GBL, add GBL-dispersed silica sol 1 and mix thoroughly to obtain polyamideimide resin (1)/silica particle mixed varnish. The solid content concentration obtained from the total mass of the polyamide imide resin (1) and the silica particles relative to the mass of the obtained varnish was set to 8.5% by mass, and the polyamide imide resin (1) was prepared A polyamide imide film (3) having a thickness of 50 μm was obtained in the same manner as in Production Example 7 except that the ratio of the silicon dioxide particle to the polyamide imide varnish (3) was 95:5.

[Manufacturing Example 10]

Manufacture of polyamideimide film (4)

Using the polyamide imide resin (3), GBL was added so that the solid content concentration became 7.7 mass %, and the polyamide imide varnish (4) was prepared. Except having used the obtained polyamide-imide varnish (4), it carried out similarly to manufacture example 7, and obtained the polyamide-imide film (4) of thickness 50 micrometers.

[Example 1]

The curable resin composition A prepared in Production Example 5 was applied to one side of the polyamideimide film (1) with a bar coater so that the thickness after drying would be 5 μm. Thereafter, the optical layered body 1 was obtained by drying at 80° C. for 3 minutes, irradiating with ultraviolet rays, and curing. The ultraviolet irradiation was carried out under a nitrogen environment with a high-pressure mercury lamp (UV exposure: 500mJ/cm ² , ultraviolet illuminance: 200mW/cm ² ). The thickness of the hard-coat layer in the obtained optical layered body 1 was 5 micrometers.

[Example 2]

An optical layered body 2 was produced in the same manner as in Example 1 except that the polyamideimide film (2) was used instead of the polyamideimide film (1).

[Example 3]

An optical layered body 3 was produced in the same manner as in Example 1 except that the curable resin composition B prepared in Production Example 6 was used on one side of the polyamideimide film (1).

[Example 4]

An optical layered body 4 was produced in the same manner as in Example 3 except that the polyamideimide film (2) was used instead of the polyamideimide film (1).

[Example 5]

The optical layered body 5 was manufactured in the same manner as in Example 1 except having set the thickness of the hard-coat layer to 10 micrometers.

[Example 6]

An optical layered body 6 was produced in the same manner as in Example 1 except that the polyamideimide film (3) was used instead of the polyamideimide film (1).

[Comparative Example 1]

The curable resin composition A prepared in Production Example 5 was applied to one side of the polyamideimide film (4) with a bar coater so that the thickness after drying became 5 μm. Thereafter, the optical layered body 7 was obtained by drying at 80° C. for 3 minutes, irradiating with ultraviolet rays, and curing. The ultraviolet irradiation was carried out under a nitrogen environment with a high-pressure mercury lamp (UV exposure: 500mJ/cm ² , ultraviolet illuminance: 200mW/cm ² ). The thickness of the hard coat layer in the obtained optical layered body 7 was 5 μm.

[Comparative Example 2]

An optical layered body 8 was produced in the same manner as in Example 1 except that a polyester film (E5000; manufactured by Toyobo Co., Ltd.) was used instead of the polyamideimide film (1).

〔Scratch test〕

The optical laminates obtained in Examples 1 to 6 and Comparative Examples 1 to 2, glass, a substitute for an organic EL panel of 100 μm, and a (meth)acrylic adhesive sheet of 25 μm were laminated in order to produce a width of 6 cm and a length of 10cm pressure scratch test sample. In each test sample, the surface on the hard coat side of the optical layered body was the outermost surface. In an environment with a temperature of 23°C and a humidity of 50%, the stylus A with a tip diameter of 0.7mm and a compressive elastic modulus of 1.0GPa, and the stylus pen B with a tip diameter of 0.7mm and a compressive elastic modulus of 3.0GPa were compared to Set the pen at 90° on the outermost surface of the test piece, and apply a load with a weight of 50g, at a speed of 500mm/min at a distance of 30mm, return waiting time (return waiting time) 2 seconds back and forth once, and implement Pressure scratch test. Then, at other places of the same test sample, the load of the weight was changed from 100 to 1100 g per 100 g unit, and the same indentation test was carried out. Afterwards, it was left standing in an environment with a temperature of 23°C and a humidity of 50%, and the maximum load at which the dent could not be recognized after 2 hours of the scratch test was determined as the critical load. The larger the maximum load, the less likely it is to dent.

〔Depression of scratches (permanent depression depth)〕

The scratch test was carried out in the same manner as the aforementioned pressure scratch test, and the test sample was left to stand for 24 hours in an environment with a temperature of 23°C and a humidity of 50%. Thereafter, using a stylus profiler system (Bruker Japan, Dektak XT-Standard), the concave shape of the part probed with a probe radius (Stylus radius): 2 μm and a probe force (Stylus Force): 3 mg was obtained. contour. Based on the two-dimensional curve chart of the obtained profile, the minimum value is obtained as the permanent depression depth based on the constant surface 0.

〔Stretching test〕

The optical layered bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were each cut into a JIS No. 2 dumbbell shape using a dumbbell cutter to obtain samples. The tensile test of these samples was carried out using a desktop precision universal testing machine (Autograph AGS-X manufactured by Shimadzu Corporation) to obtain a stress-strain curve under the conditions of a clamp distance of 80 mm and a tensile speed of 100 mm/min.

In the obtained curve, the drop point is taken when the shape changes from linear to nonlinear, and the stress value at this time is obtained as the drop stress.

〔High speed tensile test〕

The polyamideimide films obtained in Production Examples 7 to 10 were cut into JIS No. 2 dumbbell shapes using a dumbbell cutter, respectively, to obtain samples. These samples were tested using a high-speed tensile testing machine (Hydroshot HITS-T10 manufactured by Shimadzu Corporation) equipped with a load cell with a maximum load of 2KN, under the conditions of a clamp distance of 80 mm and a tensile speed of 0.1 m/s. Obtain a stress-strain curve. In the obtained curve, the point at which the curve changes from linear to nonlinear is taken as the drop point, and the stress value at this time is used as the drop stress.

〔Pencil hardness test〕

The pencil hardness of the hard-coat side surface of the optical layered body obtained in Examples 1-6 and Comparative Examples 1-2 was measured based on JISK5600-5-4:1999. The load at the time of measurement was 1 kg, and the measurement speed was 60 mm/min.

〔Bend resistance test〕

The optical layered bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were respectively cut into sizes of 10 mm in width and 100 mm in length using a laser cutting machine. When the cut optical laminate is bent The hard coating is placed on the auxiliary board (R=1.5mm) of the FOLDING MACHINE (YM-RT-330 manufactured by FOREHU) in such a way that the hard coating is on the inside, and repeated bending tests are carried out at room temperature at a test speed of 60rpm to measure The number of times that can be bent without breaking is used as the number of times of bending resistance of each optical laminate.

[Thickness of polyimide resin film and optical laminate]

The thickness of the polyimide resin film and the optical laminate was measured at 10 or more locations using a Digimatic Indicator (ID-C112XBS manufactured by Mitutoyo Co., Ltd.), and the average value was calculated.

〔Thickness of functional layer〕

The thickness of the functional layer was measured using a desktop film thickness system (manufactured by Filmetrics, F20).

The above-mentioned evaluation was performed on the polyamideimide film obtained in the above-mentioned production example or the optical laminate obtained in Examples 1 to 6 and Comparative Examples 1 to 2. Table 1 shows the obtained results.

[Table 1]

The optical layered systems described in Examples 1 to 6 have a higher critical load for two types of stylus with different compressive elastic modulus. Therefore, it was confirmed that the optical layered body of the present invention is unlikely to be dented on the surface due to contact with external factors, and that the dented surface can be easily restored. On the other hand, the optical laminates described in Comparative Examples 1 and 2 had low critical loads for the two types of stylus pens and did not have sufficient dent resistance.

Claims (10)

An optical laminate comprising a substrate layer made of a polyimide resin film and a functional layer comprising a cured product of a curable resin, wherein the stretching speed of the optical laminate is 100 mm/min The yield stress is above 100MPa. The optical laminate according to claim 1, wherein the polyimide resin film has a yield stress of 200 MPa or more at a stretching speed of 0.1 m/sec. The optical laminate as described in claim 1 or 2 has a thickness of 15 to 120 μm, and has a bending resistance of more than 200,000 times measured at R=1.5 mm. The optical laminate according to any one of Claims 1 to 3, wherein the depth of the permanent depression when measured under a load of 200 g is 0.5 μm using an auxiliary tool having a compressive modulus of elasticity of 3.0 GPa and a tip having a diameter of 0.7 mm. the following. The optical laminate according to any one of Claims 1 to 3, wherein the depth of the permanent depression when measured with a load of 1000 g is 0.5 μm using an auxiliary tool having a compressive modulus of elasticity of 1.0 GPa and a tip having a diameter of 0.7 mm the following. The optical layered body according to any one of claims 1 to 5, wherein the pencil hardness of the surface on the functional layer side is H or higher. The optical laminate according to any one of Claims 1 to 6, wherein the polyimide-based resin film comprises a polyimide-based resin, and the polyimide-based resin comprises a structure represented by formula (1) Unit, and Y in formula (1) comprises the structure shown in formula (3);

In formula (1), X represents a 2-valent organic group, Y represents a 4-valent organic group, and * represents a bonding bond;

In formula (3), R ¹ independently represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group that may have a halogen atom, and R ² to R ⁵ independently represent a hydrogen atom, or may have A valent hydrocarbon group of a halogen atom, m independently represents an integer from 0 to 3, n represents an integer from 1 to 4, * represents a bond, but in at least one benzene ring with ^R2 to ^R5 , ^R2 to At least three of R ⁵ are valent hydrocarbon groups which may have a halogen atom. A flexible display device comprising the optical laminate described in any one of Claims 1 to 7. The flexible display device as described in Claim 8 further has a touch sensor. The flexible display device according to claim 8 or 9 further includes a polarizing plate.