TW202302719A - Optical laminate and flexible display device - Google Patents

Abstract

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 stress of 110 MPa or more at a strain of 3% in a tensile testing in the environment with a temperature of 60 DEG C and a humidity of 93%.

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).

Flexible electronic devices such as flexible display devices are used in various environments. In particular, the use of flexible electronic devices is accompanied by folding or curling operations, so the polyimide resin film used as the front panel in this device can also be folded in various environments wait. Therefore, it is required that the front panel system does not cause cracks, whitening, etc. even when it is folded and the like is performed under various environments. It is especially important that cracking, whitening, etc. do not occur even when used under high-temperature conditions or high-humidity conditions. However, conventional optical films or optical laminates cannot sufficiently prevent cracking, whitening, and the like during folding operations under such high-temperature conditions or high-humidity conditions. Therefore, an object of the present invention is to provide an optical layered body that does not cause cracking, whitening, or the like even when used under high-temperature conditions or high-humidity conditions.

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, wherein the optical laminate is heated at a temperature of 60°C and a humidity of 93 The stress at 3% strain in the tensile test under the environment of % is 110MPa or more.

[2] The optical layered body according to [1], wherein the yield point strain of the optical layered body in a tensile test in an environment of a temperature of 60° C. and a humidity of 93% is 1.50% or more.

[3] The optical layered body according to [1] or [2], wherein the tensile strength of the optical layered body in an environment of a temperature of 60°C and a humidity of 93% is 70 MPa or more.

[4] The optical layered body according to any one of [1] to [3], wherein the modulus of elasticity of the optical layered body in a tensile test at a temperature of 60°C and a humidity of 93% is 4.0 GPa or more .

[5] The optical laminate according to any one of [1] to [4], wherein the polyimide resin film has a humidity expansion coefficient of 40 ppm/K or less.

[6] The optical laminate according to any one of [1] to [5], wherein the polyimide resin film has a moisture absorption rate of 3% or less under conditions of a temperature of 60°C and a humidity of 90%.

[7] The optical laminate according to any one of [1] to [6], which has a thickness of 15 to 120 μm and a bending resistance of 300,000 times or more measured at R=1.5 mm.

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

[In the 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 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].

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

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

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

According to the optical layered body of the present invention, an optical layered body that does not cause cracking, whitening, etc. even when used under high temperature conditions or high humidity conditions can be provided.

Fig. 1 is a graph showing the stress-strain curves of the optical laminates obtained in Examples and Comparative Examples measured at a temperature of 60°C and a humidity of 93%.

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.

<Optical laminate>

The optical laminate of the present invention comprises a substrate layer made of a polyimide-based resin film and a functional layer comprising a cured product of a curable resin, and the optical laminate is heated at a temperature of 60°C and a humidity of 93%. Stress at 3% strain in tensile test under ambient conditions is 110MPa or more.

When the stress of the optical layered product in the tensile test at 60°C and humidity of 93% does not reach 110MPa at a strain of 3%, it is used under high temperature or high humidity conditions with deformation such as folding operation When a flexible electronic device with an optical laminate is not sufficiently protected against Stop the occurrence of cracking, whitening, etc. The reason for this is still unclear, but when a stress higher than the yield point stress is applied to the optical laminate, a region with increased strain occurs even though the stress on the base layer is the same. The force exerted by the functional layer will become larger. It is believed that as a result, the functional layer becomes more likely to be strained, and the whitening or cracking of the film becomes more likely to occur.

From the viewpoint of easily reducing cracking and whitening when used under high-temperature and high-humidity conditions, the stress at 3% strain in the tensile test of the optical laminate in an environment at a temperature of 60°C and a humidity of 93% is preferably 111 MPa or more , more preferably above 112MPa. The upper limit of the stress at 3% strain is preferably 200 MPa or less. The above stress at 3% strain is measured in the stress-strain curve obtained by taking the optical layered body as the test sample and measuring it under the conditions of temperature 60°C, humidity 93%, clamp distance 70mm, and tensile speed 10mm/min. The value obtained by the stress at the time of straining 3% can be measured using the method described in an Example, for example.

There is no particular limitation on the method of adjusting the stress at 3% strain of the optical layered body to the above-mentioned range. For example, a polyimide resin film having a yield stress described later is used as a base layer and laminated with a curable resin. The method of the functional layer of the cured product; the method of laminating the polyimide resin film comprising the polyimide resin described later, the substrate layer, and the functional layer of the cured product comprising the curable resin, etc.

The yield point strain (Yield Strain, hereinafter also referred to as YS) in the tensile test of the optical layered body of the present invention in an environment with a temperature of 60°C and a humidity of 93% uses a tensile testing machine (test conditions: temperature 60°C, Humidity 93%, clamp distance 70mm, tensile speed 10mm/min), preferably 1.50% or more, more preferably 1.60% or more, more preferably 1.70% or more, and even more preferably 1.80% or more, Preferably it is 3.0% or less. If YS under high temperature and high humidity environment is within the above range, it is easier to reduce cracking and whitening when used under high temperature and high humidity conditions. YS Department Use the tensile testing machine under the conditions of temperature 60°C, humidity 93%, distance between clamps 70mm, and tensile speed 10mm/min, and draw the point of 0.2% strain of the stress-strain curve obtained as a reference. The strain at the point where the stress-strain curve intersects a straight line with the same slope as the elastic modulus can be measured, for example, by the method described in the examples.

In addition, the stress at this point is the endurance mentioned later.

The endurance of the tensile test of the optical laminate of the present invention in an environment with a temperature of 60°C and a humidity of 93% uses a tensile testing machine (test conditions: temperature of 60°C, humidity of 93%, clamp distance of 70mm, tensile speed 10mm/minute), preferably above 70MPa, more preferably above 75MPa, more preferably above 79MPa, preferably below 200MPa. If the durability under high temperature and high humidity environment is within the above range, it is easier to reduce cracking and whitening when used under high temperature and high humidity conditions.

The elastic modulus of the optical laminate of the present invention in the tensile test under the environment of temperature 60°C and humidity 93% uses a tensile testing machine (test conditions are temperature 60°C, humidity 93%, clamp distance 70mm, tensile Elongation speed 10mm/min), preferably above 4.0GPa, more preferably above 4.1GPa, usually below 100GPa. If the modulus of elasticity in a high-temperature and high-humidity environment is more than the above-mentioned lower limit, especially even in a high-temperature and high-humidity environment, it is easy to effectively suppress the occurrence of cracks, cracks, and wrinkles even after repeated bending. The modulus of elasticity under a high-temperature and high-humidity environment can be measured, for example, by the method described in the examples.

The number of bending resistance of the optical laminate of the present invention is preferably more than 200,000 times, more preferably more than 250,000 times, and more preferably more than 300,000 times when measured at a temperature of 60°C and a humidity of 93% at R=1.5mm . If the number of bending resistance is more than the above lower limit, especially in a high temperature and high humidity environment, Even repeated bending can effectively suppress cracks, cracks, wrinkles, etc. The number of times of bending resistance can be measured using a folding tester, for example, by the method described in the examples.

Also, when calculating the absolute value of the difference in yellowness YI (hereinafter referred to as ΔYI) of the optical layered body before and after the 300,000 times of bending test carried out under the above-mentioned conditions, ΔYI should be as small as Preferably, ΔYI is more preferably at most 0.8, more preferably at most 0.5, still more preferably at most 0.3, most preferably at most 0.25.

From the standpoint of easy improvement of folding resistance and easy prevention of wrinkles or damage, the elastic modulus of the optical layered body of the present invention at room temperature is preferably 4.0 GPa or more, more preferably 4.5 GPa or more, and even more preferably Preferably it is above 4.8 GPa, more preferably above 5.2 GPa, especially preferably above 6.0 GPa, usually below 100 GPa. In addition, the modulus of elasticity can be measured using a tensile testing machine (room temperature, humidity 50%, distance between clamps 50 mm, tensile speed 10 mm/min).

The optical layered body of the present invention preferably has excellent bending resistance. The number of bending resistance of the optical laminate of the present invention at room temperature is preferably more than 200,000 times, more preferably more than 250,000 times, and more preferably 30 times when measured at room temperature and humidity of 50% with R=1.5mm More than ten thousand times. 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. The number of times of bending resistance can be measured using a folding tester, for example, by the method described in the examples.

The yellowness (hereinafter referred to as YI) of the optical layered body of the present invention is preferably less than 3.0. When YI 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 point of view that it is easier to further improve the visibility of images transmitted through the optical layered body, the YI 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 -5 or more, more preferably -2 or more. If YI of the optical layered body is not more than the above upper limit, Then, the transparency is good, and when used for the front panel of a display device, high visibility can be imparted. 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 of the optical laminate to the above range is not particularly limited, and examples include: a method of using a polyimide-based resin described later, a method of adding a blue pigment, a method of thinning, and an aroma in the monomer main chain. A method for introducing a family 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. In addition, in this specification, the optical characteristic of an optical layered body is excellent means a high total light transmittance, and/or a low haze, and/or a low YI, and the 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 laminate is In the above-mentioned range, especially when the optical layered body is incorporated into a display device as a front plate, it is easy to improve visibility. 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, and the preferred range can be a combination of these upper and lower limits. When the thickness of the optical layered body is within the above range, it is easier to improve the bending resistance of the optical layered body in a high-temperature, high-humidity environment. Moreover, the thickness of an optical layered body can be measured using a micrometer etc., For example, it can measure by the method described in an Example. The optical laminate of the present invention may preferably have a thickness of 15 to 120 μm, more preferably 20 to 100 μm, and still more preferably 25 to 80 μm.

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 tends to be difficult to manufacture an optical layered body having a high total light transmittance and a low haze for a thick film. 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 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, and particularly preferably at least 35 μm. More preferably, it is more than 40 μm; more preferably, it is less than 100 μm, more preferably, it is less than 80 μm, and more preferably, it is less than 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.

(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. A polyimide resin is a resin containing a repeating structural unit containing an imide group, and a polyamide imide resin is a resin containing a repeating structural unit containing both an imide group and an amido group. 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 viewpoint of easily suppressing cracking, whitening, etc. even when the optical laminated body of the present invention is used under high-temperature and high-humidity conditions, the polyimide-based resin contained in the polyimide-based resin film is preferably polyimide-based resin. Amide resin or polyamide imide resin, more preferably polyamide imide resin.

In a preferred embodiment of the present invention, from the viewpoint of easily reducing cracking and whitening during folding, especially under high temperature and high humidity conditions, and easily improving chemical stability, polymer The imide resin is preferably an aromatic resin. 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 standpoint of easily reducing cracking and whitening during folding and improving chemical stability, the structural unit derived from the aromatic monomer is less than that contained in the imide resin. The proportion of all structural units is preferably more than 60 mole%, more preferably More than 70 mole%, more preferably more than 80 mole%, and more preferably more than 85 mole%. 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 In this case, the aryloxy group is preferably a valent hydrocarbon group which may have a halogen atom, an alkoxy group or an aryloxy group having 1 to 8 carbon atoms. 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.

In the polyimide-based resin, Y in the formula (1) preferably includes the structure represented by the 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, pyl, 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. In the optical layered body having a polyimide resin film, ^R1 is preferably an alkyl group that may have a halogen atom independently of each other from the viewpoint of easily reducing cracking and whitening due to folding and improving transparency. or an alkoxy group, 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 the formula (3), from the viewpoint of easily reducing the cracking and whitening of the optical layered body during folding and improving the transparency, m independently represents an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, 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, pyl, 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 standpoint of improving the solubility of the resin to solvents, reducing cracking and whitening when folding the optical laminate, and improving transparency, R ² to R ⁵ are preferably hydrogen atoms independently of each other, or may have The alkyl group of a halogen atom is more preferably a hydrogen atom or an alkyl group of 1 to 6 which may have a halogen atom, still more preferably a hydrogen atom or an alkyl group of 1 to 3 which may have a halogen atom.

Of the at least one benzene ring having ^R2 to ^R5 in formula (3), when at least three of ^R2 to ^R5 are a valent hydrocarbon group that may have a halogen atom, it is easy to reduce the cracking when folding the optical layered body and albino. In addition, the solubility of the polyimide-based resin in solvents can be improved.

From the standpoint of improving the solubility of the resin to solvents, reducing cracking and whitening when folding the optical laminate, and improving transparency, when n is 2 or more, it is preferable to have at least R ² to R ⁵ Among the two benzene rings, at least three of ^R2 to ^R5 are a valent hydrocarbon group that may have a halogen atom; more preferably among all benzene rings having ^R2 to ^R5 , at least ^three of R2 to ^R5 are Three are valent hydrocarbon groups which may have a halogen atom.

In the formula (3), n represents an integer of 1 to 4. From the viewpoint of easily improving the modulus of elasticity and transparency of the polyimide-based lipid film, and easily reducing cracking and whitening when the optical laminate is folded, 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 preferably represented by formula (3'). If it is this form, it will become easy to reduce cracking and whitening at the time of folding 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 %. When the ratio of Y being the structural unit represented by formula (3) is more than the above-mentioned lower limit, cracking and whitening at the time of folding an optical layered body will become easy to reduce. 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 formula (5) is further included as Y in formula (1), it is easier to reduce cracking and whitening when folding the optical layered body, and it is easier to improve 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 of easily reducing cracking and whitening when folding the optical laminate and improving transparency, ^R7 are independent of each other, preferably an alkyl group having 1 to 6 carbon atoms that may have a halogen atom, and more preferably an alkyl group that may have a halogen atom. An alkyl group having 1 to 3 carbon atoms having a halogen atom.

In the formula (5), t represents an integer of 0 to 3, and is preferably an integer of 0 to 2, more preferably represents 0 or 1, 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 easily reducing cracking and whitening when folding the optical layered body and improving transparency, B in formula (5) preferably includes a single bond or a divalent hydrocarbon group that may have a halogen atom, more preferably is a single bond, -CH ₂ -, -CH ₂ -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 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 easy to reduce cracking and whitening at the time of folding an optical layered body, and it becomes easy 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 modulus of elasticity of the resin film. Moreover, if this ratio is below the said upper limit, it will become easy to reduce the crack and whitening at the time of folding 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-in 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 to the structural unit represented by the formula (5) is more than the above-mentioned lower limit, it is easy to reduce cracking and whitening when the optical laminate is folded, and more It is easy to improve transparency. Moreover, if this ratio is below the said upper limit, it will become easy to raise the 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 by, for example, ¹ H-NMR, 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 within the above range, the elastic modulus and transparency of the polyimide-based resin film will be easily improved, and cracks and whitening at the time of folding the optical layered body will be 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 formulas (20) to (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; Hydrocarbyl. Also, the hydrogen atoms on the rings in the formulas (20) to (29) 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 terms of easily reducing cracking and whitening when folding the optical laminate, increasing the modulus of elasticity, and improving transparency more easily, the group represented by formula (20) to formula (29) is preferably formula (26) , a group represented by formula (28) or formula (29), more preferably a group represented by formula (26). In addition, 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 -, particularly preferably -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, the polyimide-based resin is easy to reduce cracking and whitening when the optical laminate is folded, easy to increase the modulus of elasticity, and more likely to improve transparency. X preferably contains at least one of a divalent aromatic group, a divalent alicyclic group, and a divalent aliphatic group, and more preferably 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.

From 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 C1-12 C1-valent hydrocarbon group which may have a halogen atom. The C1-C12 valent hydrocarbon group which may have a halogen atom is exemplified as the valent hydrocarbon group which may have a halogen atom in R2 ^{- R5} of said 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 elastic modulus and transparency of the polyimide-based resin film and the optical layered body, and it is easy to reduce cracking and whitening when the optical layered body is folded. 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 elastic modulus and transparency of the polyimide-based resin film and the optical laminate, and easily reducing the cracking and whitening of the optical laminate when folding, the R ⁶ series are independent of each other, and are relatively independent of each other. Preferably it is an alkyl group with 1 to 6 carbons or a halogenated alkyl group with 1 to 6 carbons, more preferably an alkyl group with 1 to 6 carbons or a fluoroalkyl group with 1 to 6 carbons, more preferably a perfluoroalkyl group . In a preferred form, R ⁶ are independently methyl, chloro or trifluoromethyl. s independently represent an integer of 0 to 4, from the viewpoint that it is easy to improve the elastic modulus and transparency of the polyimide resin film and the optical laminate, and it is easy to reduce cracking and whitening when the optical laminate is folded, It is preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1.

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

In the formula (4), the positions of the bonding bonds are independent of each other, so that it is easy to improve the elastic modulus and transparency of the polyimide resin film and the optical laminate, and it is easy to reduce the cracking and whitening of the optical laminate when folding. From a point of view, when -A- is used as a reference, meta or para is preferable, and para is more preferable.

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 may replace two hydrogen atoms from the hydrogen atoms contained in the group to form a ring, that is, replace the two hydrogen atoms as bonding bonds and connect the two bonding bonds to form a ring, Such a 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 the formula (4) can be exemplified as the above-mentioned ones in the formula (3) ) in R ¹ in which the alkyl group which may have a halogen atom is exemplified.

From the viewpoints that it is easier to reduce cracking and whitening when folding the optical laminate, it is easier to increase the modulus of elasticity, and it is easier to improve 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 -, 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 modulus of elasticity and transparency of the polyimide resin film and the optical laminate and easily reducing cracking and whitening when the optical laminate is folded, 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 to say, at least a part of the plurality of Xs in formula (1) is preferably represented by formula (4'). According to this form, it is easy to reduce cracking and whitening at the time of folding the optical layered body, it is easy to increase the modulus of elasticity, and it is easier to improve 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 easy to reduce cracking and whitening when the optical layered body is folded, and it is easy to further increase the 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 formula (9), it is easy to reduce cracking and whitening when folding the optical layered body, and it is easy to further increase the 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, from the viewpoint of making it easier to reduce cracking and whitening during folding of the optical laminate and to further increase the modulus of elasticity, the polyamide-imide resin has an amount of all the structural units contained in the polyamide-imide resin. The ratio of the amide component contained in the imide resin is preferably at least 5 mol %, more preferably at least 10 mol %, more preferably at least 15 mol %, and still more preferably at least 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 can 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 point of view that it is easy to reduce the YI of the polyimide resin film, it is easy to increase the total light transmittance, and it is easy to reduce the haze, the ring structure in Z is preferably represented by formula (20) to formula (29) A group and a 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).

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 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, * 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 form of record 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 may, for example, be phenyl, tolyl, pyl, naphthyl or biphenyl. From the viewpoint of elastic modulus, surface hardness, and flexibility of the polyimide resin film and the optical laminate, R ^3a and R ^3b are preferably an alkyl group or a carbon number of 1 to 6 independently of each other. The alkoxy group of 1 to 6 is more preferably 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 in this range, it is easy to improve the elastic modulus and durability of the polyimide resin film and the optical laminate. Flexibility, and easy to reduce cracking and whitening when folding the optical laminate. In formula (6) and formula (6'), s is preferably in the range of 0 to 3 from the viewpoint of making it easier to improve the elastic modulus and bending resistance of the polyimide resin film and the optical laminate. The integer 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 elastic modulus and bending resistance of the polyimide resin film and the optical laminate, and reducing YI, Z is preferably represented by formula (6) or In the formula (6'), wherein, s is 0, and u is preferably 1-3, 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, it is easy to improve the elastic modulus and bending resistance of the polyimide resin film and the optical laminate. 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. Moreover, 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, and can also be calculated from the charging ratio of a raw material.

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 a structural unit represented by formula (6) or formula (6') in which s is 0 to 4, it is easy to improve the elastic modulus and bending resistance of the polyimide resin film and the optical laminate. sex. Also, as long as 100 mol% or less of Z in the polyamideimide resin is a structural unit represented by formula (6) or formula (6') in which s is 0 to 4, it is sufficient. 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-mentioned lower limit, the impact resistance and elastic modulus of the polyimide-based resin film and the optical layered body can 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 the 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 a hydrocarbon group or a fluorine-substituted hydrocarbon group. ^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. In addition, from the viewpoint of reducing cracking and whitening when the optical laminate is folded, bending resistance, and easily improving the transparency and elastic modulus of the polyimide resin film, among the above polyimide resins, based on All structural units shown in formula (1) and formula (2), and optional formula (30) and formula (31), the ratio of structural units shown in formula (1) and formula (2) is preferably 80 mo More than mol%, more preferably more than 90 mol%, and more preferably more than 95 mol%. 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 modulus of elasticity of the polyimide resin film, and it is easy to reduce the folding time of the optical laminate. Cracking and bleaching.

From the standpoint of easily reducing cracking and whitening when folding the optical laminate and improving the 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 at least 230,000, more preferably at least 250,000, still more preferably at least 270,000, particularly preferably at least 280,000, and most preferably at least 300,000. In addition, from the viewpoint of easily improving the solubility of the resin in solvents and improving the extensibility and processability of the polyimide resin film, the weight average molecular weight of the polyimide resin It is preferably at most 1,000,000, more preferably at most 800,000, more preferably at most 700,000, still more preferably at most 500,000. 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, it is easy to increase the modulus of elasticity of the polyimide-based resin film and the optical laminate and lower the YI. When YI 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 the 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 to 40% by mass. 30% by mass. When the content of the halogen atoms is within the above range, it is easy to further increase the elastic modulus of the polyimide resin film and the optical laminate, further reduce the YI, further improve the transparency and visibility, and become easy to synthesize.

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%, even more preferably at least 96%, and usually not more than 100%. polyimide tree From the viewpoint of the optical properties of the lipid film and the optical layered body, the imidization rate is preferably at least the above lower limit. The imidization rate means 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 proportion. 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.

From the viewpoint of easily reducing the cracking and whitening of the optical layered body including the film when it is folded under high-temperature and high-humidity conditions, the humidity of the polyimide-based resin film contained as the base material layer in the optical layered body of the present invention The coefficient of expansion (hereinafter referred to as "CME") is preferably less than 40ppm/K, more preferably less than 35ppm/K, more preferably less than 30ppm/K, more preferably less than 25ppm/K, and most preferably less than 20ppm /K or less, usually 0ppm/K. The smaller the humidity expansion rate, the better. CME can be the humidity expansion rate of the film when the temperature is controlled at 60° C. and the humidity is 90% for 1 hour. For example, it can be measured by the method described in the examples.

From the point of view of easily reducing the cracking and whitening of the optical laminated body containing the film when it is folded under high temperature and high humidity conditions, the moisture absorption rate of the polyimide resin film under the conditions of temperature 60°C and humidity 90% is relatively low. Preferably it is 3% or less, more preferably 2.8% or less, still more preferably 2.7% or less. The moisture absorption rate under the conditions of a temperature of 60° C. and a humidity of 90% can be measured using a thermomechanical analysis device, for example, by 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. Preferably at least 45 μm, preferably at most 200 μm, more preferably at least 100 μm Below, more preferably below 80 μm, particularly preferably below 60 μm, the preferred range may be a combination of these upper and lower limits. If the thickness of the polyimide resin film is within the above range, it is easy to adjust the stress of the optical layered body at a strain of 3% within the above range, and it is easy to reduce the stress when the optical layered body is folded under high temperature and high humidity conditions. Cracking and bleaching.

From the viewpoint of easily obtaining the above-mentioned characteristics of the optical laminate, the modulus of elasticity, number of times of folding, YI, total light transmission The ratio and the haze are preferably within the preferred ranges described above for the optical layered body 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 (6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane di anhydride, 1,1-bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethanedianhydride, 1,1-bis(3, 4-dicarboxyphenyl) ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(para Phenyl dioxy) diphthalic dianhydride, 4,4'-(m-phenylene dioxy) 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 alone Use or combine 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 elastic modulus, high surface hardness, high transparency, high flexibility, high bending resistance and low coloring. From the viewpoint of properties, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, BPDA, 2,2' ,3,3'-Biphenyltetracarboxylic dianhydride, 3,3',4,4'-Diphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl) Propaned anhydride, 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 ylphenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis( Trifluoromethyl)-4,4'-diaminodiphenyl (also known 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- Aromatic diamines having two or more aromatic rings, such as bis(4-amino-3-fluorophenyl) fluorine. 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 selected from the group consisting of polyimide resins 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 of the 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) (also described as OBBC), terephthalyl chloride or isophthalyl chloride, more preferably a combination 4,4'-Oxybis(benzoyl chloride) and terephthalyl chloride were used.

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 their similar acyl chlorides, acid anhydrides, and the like, 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) Isoamide-based solvents; sulfur-containing solvents such as dimethylsulfide, dimethylsulfoxide, and cyclobutylene; ethylene carbonate Carbonate-based solvents such as esters and propylene carbonate; and combinations thereof, that is, mixed solvents, and the like. 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- Pyridine (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 solution 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 fluoride and sodium fluoride, etc. Among these, silicon dioxide particles are preferable from the viewpoint of easiness of increasing the elastic modulus of the polyimide resin film and the optical laminate. , 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 less than 90nm, more preferably less than 80nm, still more preferably less than 70nm, most preferably less than 60nm, particularly preferably less than 50nm, and most preferably less than 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 or a scanning electron microscope.

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 becomes easy to raise the 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. ultraviolet light The 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 when the obtained optical laminate is applied to an image display device or the like can be improved. 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 the other additives is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the polyimide resin film. parts by mass.

[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 above-mentioned resin, for example, a solvent used for preparing a varnish described below, and the solvent-substituted 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 rolls such as wire bar coating, reverse coating, and gravure coating. Coating method, die coating method, chipping wheel coating method, lip coating method, spin coating method, screen coating method, spray column (fountain) coating method, dipping method, spray method, flow Extensive molding, 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. The coating can be dried in an inert environment or under reduced pressure if necessary. 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, PET films and cycloolefin-based polymer films are preferable from the viewpoint of excellent smoothness and heat resistance, and more preferable from the viewpoint of adhesion to polyimide-based resin films and cost. For 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 range, cracking and whitening at the time of folding the optical layered body can be reduced, impact resistance can be further improved, and bending resistance tends to be less likely to be lowered. The hard coat layer can be formed by hardening a hard coat composition including 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 contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound.

The aforementioned radical polymerizable compound is a compound having a radical polymerizable group. As for the radical polymerizable group possessed by the above-mentioned radical polymerizable compound, as long as it is a functional group capable of radical polymerization reaction, a group containing a carbon-carbon unsaturated double bond and the like can be mentioned, specifically, it can be A vinyl group, a (meth)acryloyl 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 known as polyfunctional acrylate monomers, or (meth)acrylate epoxy esters, (meth)acrylate amine esters, polyester (meth)acrylates, etc. have several ( Oligomerization of meth)acryl groups with a molecular weight of hundreds to thousands Preferably, one or more selected from the group consisting of epoxy (meth)acrylate, amine (meth)acrylate, and polyester (meth)acrylate is mentioned.

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 region 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 , caprolactone adducts and other derivatives Glycidyl ether produced by reaction with epichlorohydrin and glycidyl ether type epoxy resin derived from bisphenols such as novolac epoxy resin, 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 functional layer comprising a cured product of a curable resin is formed, for example, in a hard coat layer by irradiating a coating film with high-energy rays such as active energy rays to harden the coating film to form a hard coat layer. 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, a thermosetting resin composition or a photosetting resin composition can be 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 coloring agent include inorganic pigments such as titanium oxide, zinc oxide, iron oxide red, titanium oxide-based fired pigments, ultramarine blue, cobalt aluminate, and carbon black; azo compounds, quinacridone compounds, anthraquinone series compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinolinone-based compounds, threne-based compounds, and diketopyrrolopyrrole-based compounds Organic pigments such as compounds; extender pigments such as barium sulfate and calcium carbonate; 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 setting the average primary particle size of the pigment to 0.1 μm or less, diffuse reflection of light passing through the refractive index adjustment layer can be prevented, and a decrease in transparency can be prevented. 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. In addition, the 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 in 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 Before the flexible display device, the film system for the panel 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 total light transmittance, haze and/or YI described above. From the viewpoint of 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 wearable devices such as televisions, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, indicators, message boards, clocks, and smart watches. 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. The circular polarizing plate is a functional layer that has a function of transmitting only the right circularly polarized light component or the left circularly polarized light component by laminating a λ/4 retardation plate on the linear polarizing plate. 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 above-mentioned liquid crystal polarizing layer may be peeled from the substrate and transferred to be laminated, or may be laminated while maintaining the above-mentioned 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.

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 initiators, solvents, dispersants, leveling agents, stabilizers, surfactants, crosslinking agents, silane coupling agent etc. 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 retardation plate, It can also be an extended retardation 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. Among them, an 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 Since the unit patterns are separated from each other in the form of islands, separate bridge electrodes are required to electrically connect the second patterns. The sensing pattern can use known transparent electrode materials. 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. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium. These 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 for properly compensating the difference in transmittance between the patterned area and the non-patterned area where no pattern is formed. Specifically, As a means of properly compensating for the difference in light transmittance caused by the difference in refractive index in these regions, the aforementioned optical adjustment layer system 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 binder 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 aforementioned main agent polymer, it can also be mixed with With cross-linking agent, silane compound, ionic compound, cross-linking catalyst, antioxidant, dye, pigment, inorganic filler, organic solvent, etc. 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 the aforementioned water-based solvent-volatile adhesive is used, the thickness of the adhesive layer 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. Hard coating group In the description of the product, an initiator that initiates at least one of radical polymerization or cationic polymerization by irradiating active energy rays can be used.

The active energy ray curable composition may further contain ion scavengers, antioxidants, chain transfer agents, adhesion imparting agents, thermoplastic resins, fillers, flow viscosity modifiers, plasticizers, defoaming agents, solvents, additives, and 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 hard to be seen, 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 light-shielding pattern is not particularly limited, and may have various colors such as black, white, and metallic. 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. First, the measurement method of each physical property value etc. is demonstrated.

<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.

<Measurement of yellowness (YI)>

The yellowness (Yellow Index: YI) of the optical laminates obtained in Examples and Comparative Examples was measured using an ultraviolet-visible-near-infrared spectrophotometer (V-670 manufactured by JASCO Corporation) in accordance with JIS K 7373:2006. After the background measurement was performed without the membrane, the membrane was mounted on the sample holder, and the transmittance with respect to light of 300 to 800 nm was measured to obtain three excitation values (X, Y, Z). YI is calculated according to the following formula.

YI=100×(1.2769X-1.0592Z)/Y.

[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 digital indicator (Digimatic Indicator) (manufactured by Mitutoyo Co., Ltd., ID-C112XBS), 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).

<Film bending test>

The optical layered bodies obtained in Examples and Comparative Examples were used as measurement samples, and a bending test was implemented using a bending tester (manufactured by Yuasa System Co., Ltd., ML11MC-CET02A).

(high temperature and high humidity bending test)

Repeat the bending test 300,000 times under the conditions of temperature 60°C, humidity 93%, 60 times/minute, R=1.5mm, and measure the number of times when the film is whitened and broken. Also, YI was measured at the point in time when the number of times of bending was 100,000, and the difference from YI before the bending test was calculated as ΔYI.

<Tensile test>

The optical layered bodies obtained in Examples and Comparative Examples were cut into JIS No. 2 dumbbell shapes using a dumbbell cutter, respectively, to obtain samples. The measurement was performed using a desktop precision universal testing machine (manufactured by Shimadzu Corporation, Autograph AGS-X) and a constant temperature and humidity chamber (manufactured by Shimadzu Corporation, THC1). Under the conditions of temperature 60°C, humidity 93%, fixture distance 70mm, and tensile speed 10mm/min, the sample was installed on a desktop precision universal testing machine, and the stress-strain at the time point when the temperature and humidity became fixed was measured. curve. The modulus of elasticity was calculated from the slope of the obtained stress-strain curve. Also, when drawing a straight line with the same slope as the elastic modulus based on the 0.2% strain point of the stress-strain curve, set the strain at the point compared with the stress-strain curve as YS, and calculate the Stress as endurance. Next, the stress at the time of the strain of 3% was calculated as the stress at the time of the strain of 3%.

<Determination of Humidity Expansion Coefficient CME>

After adjusting from a temperature of 60°C and a humidity of 0% to a temperature of 60°C and a humidity of 90%, it was measured using a thermomechanical analyzer (manufactured by hitachi-hightech Co., Ltd., TMA/SS6100) under a load of 20mN of tensile load The expansion rate of the optical layered body after holding for 1 hour was obtained, and the humidity average linear expansion coefficient was obtained from the obtained expansion rate.

<Moisture absorption rate measured at 60°C and 90% humidity>

Measurement was performed using a differential thermogravimeter (manufactured by SEIKO Electronics Industry Co., Ltd., TG/DTA6200). Set the film cut into a 15mm square size in a sample dish, and set the measurement conditions at a temperature of 60°C and a humidity of 90%. After standing still until the mass of the sample is stable, measure the mass of the sample every 10 seconds, calculate the average value of the measured values for one minute, and calculate the moisture absorption rate from the mass change according to the following formula.

Moisture absorption (mg) = mass of sample with 90% humidity (mg) - mass of sample before humidification (mg).

Moisture absorption rate (%) = moisture absorption (mg) ÷ sample mass before humidification (mg) × 100.

<Manufacturing Example 1: Preparation of Photocurable Resin Composition A for Hard Coating>

19 parts by mass of urethane acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., MIRAMER PU620D), 19 parts by mass of multifunctional 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 JAPAN Co., Ltd., BYK (registered trademark) )-307) 0.3 parts by mass were stirred and mixed to obtain a photocurable resin composition A.

<Manufacturing Example 2: Preparation of Photocurable Resin Composition B for Hard Coating>

18 parts by mass of urethane acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., MIRAMER PU620D), 18 parts by mass of polyfunctional acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., MIRAMER SP1106), containing (methyl) 1.8 parts by mass of lithium salt of acrylate group and anion (manufactured by Specific Polymers, MTFSiLi), 60 parts by mass of methyl ethyl ketone (manufactured by Tokyo Chemical Industry Co., Ltd.), leveling agent (manufactured by BYK JAPAN Co., Ltd., BYK (registered trademark) -307) 0.3 mass parts were stirred and mixed, and the photocurable resin composition B was obtained.

<Manufacturing Example 3: Preparation of Polyamideimide 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 (10.8 mmol) of tetracarboxylic dianhydride (TMPBP-TME) represented by the following chemical 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 4: Film Formation of Polyamideimide Film (1)>

DMAc was added to the polyamideimide resin (1) obtained in Production Example 3 so that the concentration would be 10.5% by mass to prepare a polyamideimide varnish (1). The obtained polyamideimide varnish (1) was coated on the smooth surface of the glass substrate using an applicator so that the thickness of the self-supporting 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.

<Example 1: Formation of an optical laminate (1)>

On one side of the polyamideimide film (1) obtained in Production Example 4, the photocurable resin composition A was coated with a bar coater so that the thickness after drying would be 10 μm. Then, it dried at 80 degreeC for 3 minutes, irradiated with ultraviolet rays, and hardened|cured, and the optical layered body (1) was obtained. 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 10 micrometers.

<Example 2: Formation of an optical laminate (2)>

On one side of the polyamideimide film (1) obtained in Production Example 4, the photocurable resin composition A was coated with a bar coater so that the thickness after drying became 5 μm. In the same manner as in Example 1, an optical layered body (2) was obtained. The thickness of the hard coat layer in the optical laminate (2) was 5 μm.

<Manufacturing Example 5: Preparation of GBL-dispersed silica sol>

In a 2000 mL flask, 393.4 g of methanol-dispersed silica sol (manufactured by Nissan Chemical Industries, Ltd., MA-ST-G-ML1; primary particle size: 27 nm, solid content of silica particles: 30.5% by mass) and 261.0 g of GBL were charged, Use a vacuum evaporator to evaporate methanol at 400 hPa for 40 minutes and at 250 Pa for 60 minutes in a hot water bath at 45°C. 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 6: Film Formation of Polyamideimide Film (2)>

Dissolve the polyamideimide resin (1) obtained in Production Example 3 in GBL, add the silica sol dispersed in GBL obtained in Production Example 5 and mix thoroughly to obtain polyamideimide resin (1)/two Silica particle mixed varnish. The solid content concentration calculated from the total mass of the polyamide imide resin (1) and the silica particles relative to the mass of the obtained varnish was set at 10.0% by mass so that the polyamide imide resin (1) and The mass ratio of the silica particles was 80:20 to obtain a polyamideimide varnish (2).

A polyamide-imide film (2) having a thickness of 50 μm was obtained in the same manner as in Production Example 4 except that the polyamide-imide varnish (2) was used instead of the polyamide-imide varnish (1).

<Example 3: Formation of optical layered body (3)>

An optical laminate (3) was obtained in the same manner as in Example 2 except that the polyamideimide film (2) obtained in Production Example 6 was used instead of the polyamideimide film (1) obtained in Production Example 4. . The thickness of the hard coat layer in the optical layered body (3) was 5 μm.

<Manufacturing Example 7: Preparation of Polyamideimide Resin (2)>

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. Next, the reaction liquid 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. Then, OBBC 1.7091g (5.791mmol) and TPC 6.576g (32.39mmol) were added to the flask, and it stirred at 10 degreeC for 2 hours. Next, 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-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. catch The precipitate was dried under reduced pressure at 80° C. to obtain a polyamide imide resin (2). The Mw of the polyamideimide resin (2) was 300,000.

<Manufacturing Example 8: Film Formation of Polyamideimide Film (3)>

Dissolve the polyamideimide resin (2) obtained in Production Example 7 in GBL, add the silica sol dispersed in GBL obtained in Production Example 5 and mix thoroughly to obtain polyamideimide resin (2)/dioxide Silica particle mixed varnish. The solid content concentration obtained from the total mass of the polyamide imide resin (2) and the silica particles relative to the mass of the obtained varnish was set at 10.5% by mass so that the polyamide imide resin (2) and The mass ratio of the silica particles was 80:20 to obtain a polyamideimide varnish (3).

A polyamide-imide film (3) having a thickness of 50 μm was obtained in the same manner as in Production Example 4 except that the polyamide-imide varnish (3) was used instead of the polyamide-imide varnish (1).

<Comparative Example 1: Film Formation of Optical Laminate (4)>

On one side of the polyamideimide film (3) obtained in Production Example 3, the photocurable resin composition B was coated with a bar coater so that the thickness after drying became 10 μm. In the same manner as in Example 1, an optical layered body (4) was obtained. The thickness of the hard coat layer in the optical layered body (4) was 10 μm.

For the polyamide imide films (1) to (3) or optical laminates (1) to (4) obtained in the above manner, the yellowness YI, ΔYI, and bending resistance were measured according to the measurement methods described above. Times, elastic modulus, endurance, YS and stress at 3% strain. The obtained results are shown in Table 1. Also, the stress-strain curves of the optical laminates (1) to (4) measured at a temperature of 60°C and a humidity of 93% are shown in Fig. 1 .

Claims (11)

An optical laminate comprising a base material layer made of a polyimide resin film and a functional layer comprising a cured product of a curable resin, wherein the optical laminate is placed in an environment with a temperature of 60°C and a humidity of 93%. The stress at 3% strain in the following tensile test is 110MPa or more. The optical layered body according to claim 1, wherein the yield point strain of the optical layered body in a tensile test in an environment of a temperature of 60°C and a humidity of 93% is 1.50% or more. The optical layered body according to claim 1 or 2, wherein the tensile strength of the optical layered body in an environment of a temperature of 60°C and a humidity of 93% is 70 MPa or more. The optical layered body according to any one of claims 1 to 3, wherein the optical layered body has an elastic modulus of 4.0 GPa or more in a tensile test in an environment of a temperature of 60° C. and a humidity of 93%. The optical laminate according to any one of claims 1 to 4, wherein the polyimide resin film has a humidity expansion coefficient of 40 ppm/K or less. The optical laminate according to any one of claims 1 to 5, wherein the polyimide resin film has a moisture absorption rate of 3% or less under conditions of a temperature of 60°C and a humidity of 90%. The optical laminate according to any one of Claims 1 to 6, which has a thickness of 15 to 120 μm and a bending resistance measured at R=1.5mm of 300,000 or more. The optical laminate according to any one of Claims 1 to 7, wherein the polyimide-based resin film contains a polyimide-based resin, and the polyimide-based resin contains a structural unit represented by formula (1) , 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 8. The flexible display device according to claim 9 further has a touch sensor. The flexible display device according to claim 9 or 10 further includes a polarizing plate.

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