TW202122472A - Polyamideimide resin - Google Patents

Abstract

Provided are: a polyamideimide resin which can provide an optical film having high strength; and said optical film. The polyamideimide resin according to the present invention includes structural units represented by formula (1) and formula (2), and includes a structure, represented by formula (3), as Y in formula (1).

Description

Polyimide resin

The present invention relates to a polyimide resin and an optical film containing the polyimide resin.

Display devices such as liquid crystal display devices or organic EL (ELectroluminescence) display devices are widely used in various applications such as mobile phones and smart watches. Glass has always been used as the front panel of such a display device, but the glass is very rigid and easily broken, so it is difficult to use it as a material for the front panel of a flexible display device, for example. Therefore, as a material to replace glass, the use of polymer materials is being studied. Before the polymer material is included, the panel tends to exhibit flexibility, so it can be expected to be used in various applications. As the resin having flexibility, various resins can be cited, and one of them is a polyimide-based resin. For example, Patent Document 1 and Patent Document 2 describe optical films formed of polyimide resin or polyimide resin. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2014/046180 [Patent Document 2] International Publication No. 2016/152459

[The problem to be solved by the invention]

Optical films used in materials such as flexible display devices are required to have features such as folding resistance. The inventors of the present invention conducted intensive studies in order to improve the required performance of the optical film and found that by improving the endurance of the optical film, an optical film with excellent folding resistance and the like can be obtained.

Therefore, the object of the present invention is to provide a polyamide imide resin capable of providing an optical film with high durability, and the optical film. [Technical means to solve the problem]

[式(1)及式(2)中，X及Z相互獨立地表示2價有機基，Y表示4價有機基，*表示鍵結鍵] 所表示之結構單元，且包含式(3)： [化2]

[式(3)中，R¹ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，R² ～R⁵ 相互獨立地表示氫原子或可具有鹵素原子之1價烴基，m相互獨立地表示0～3之整數，n表示1～4之整數，*表示鍵結鍵，其中，於具有R² ～R⁵ 之至少1個苯環中，R² ～R⁵ 之至少1個為可具有鹵素原子之1價烴基] 所表示之結構作為式(1)中之Y。 [2]如上述[1]中記載之聚醯胺醯亞胺樹脂，其包含2價芳香族基、2價脂環族基及2價脂肪族基之至少1種作為式(1)及式(2)中之X。 [3]如上述[1]或[2]中記載之聚醯胺醯亞胺樹脂，其 包含式(4)： [化3]

[式(4)中，A表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R^A1 )-或-Si(R^A2 )₂ -，R^A1 及R^A2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁶ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，s相互獨立地表示0～4之整數，*表示鍵結鍵] 所表示之結構作為式(1)及式(2)中之X。 [4]如上述[1]至[3]中任一項中記載之聚醯胺醯亞胺樹脂，其 進而包含式(5)： [化4]

[式(5)中，B表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-COO-、-PO-、-PO₂ -、-N(R^B1 )-或-Si(R^B2 )₂ -，R^B1 及R^B2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁷ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，t相互獨立地表示0～3之整數，*表示鍵結鍵] 所表示之結構作為式(1)中之Y。 [5]如上述[1]至[4]中任一項中記載之聚醯胺醯亞胺樹脂，其 包含式(6)： [化5]

[式(6)中，W相互獨立地表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R^C1 )-或-Si(R^C2 )₂ -，R^C1 及R^C2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁸ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，p相互獨立地表示0～4之整數，q表示0～4之整數，*表示鍵結鍵] 所表示之結構作為式(2)中之Z。 [6]如上述[1]至[5]中任一項中記載之聚醯胺醯亞胺樹脂，其重量平均分子量為100,000以上。 [7]一種光學膜，其包含如上述[1]至[6]中任一項中記載之聚醯胺醯亞胺樹脂。 [8]如上述[7]中記載之光學膜，其黃度未達3.0。 [9]如上述[7]或[8]中記載之光學膜，其全光線透過率為90%以上。 [10]如上述[7]至[9]中任一項中記載之光學膜，其彈性模數為5.0 GPa以上。 [11]如上述[7]至[10]中任一項中記載之光學膜，其係可撓性顯示裝置之前面板用膜。 [12]一種可撓性顯示裝置，其具備如上述[7]至[11]中任一項中記載之光學膜。 [13]如上述[12]中記載之可撓性顯示裝置，其進而具備觸控感測器。 [14]如上述[12]或[13]中記載之可撓性顯示裝置，其進而具備偏光板。 [發明之效果]The inventors of the present invention have completed the present invention after diligent research in order to solve the above-mentioned problems. That is, the present invention provides the following preferred aspects. [1] A polyamide imine resin comprising formula (1) and formula (2): [化1]

[In formula (1) and formula (2), X and Z independently represent a divalent organic group, Y represents a tetravalent organic group, and * represents a bonding bond] The structural unit represented, and includes the formula (3): [化2]

[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 halogen A monovalent hydrocarbon group of atoms, m independently represents an integer from 0 to 3, n represents an integer from 1 to 4, * represents a bonding bond, wherein, in at least one benzene ring ^{having R 2} to R ^{5 , R 2} At least one of ~R ⁵ is a monovalent hydrocarbon group which may have a halogen atom] The structure represented by the structure represented is as Y in the formula (1). [2] The polyamideimide resin as described in [1] above, which contains at least one of a divalent aromatic group, a divalent alicyclic group, and a divalent aliphatic group as formula (1) and formula (2) The X in. [3] The polyamide resin as described in [1] or [2] above, which comprises the formula (4): [化3]

[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 that may have a halogen atom, and R ⁶ independently represent a halogen atom, An alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, s independently represents an integer of 0-4, and * represents a bonding bond] The structure represented is as formula (1) and formula (2) Among the X. [4] The polyamide resin as described in any one of [1] to [3] above, which further comprises the formula (5): [化4]

[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, and R ⁷ are mutually independent It represents a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, t independently represents an integer of 0 to 3, and * represents a bonding bond] The structure represented is as in formula (1) Of Y. [5] The polyimide resin as described in any one of [1] to [4] above, which comprises the formula (6): [化5]

[In formula (6), W independently 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 ^C1 )- or -Si(R ^C2 ) ₂ -, R ^C1 and R ^C2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom, and R ⁸ independently represent each other A halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, p independently represents an integer from 0 to 4, q represents an integer from 0 to 4, * represents a bonding bond] The structure is the Z in formula (2). [6] The polyimide resin as described in any one of [1] to [5] above, which has a weight average molecular weight of 100,000 or more. [7] An optical film comprising the polyamide imide resin as described in any one of [1] to [6] above. [8] The optical film as described in [7] above, which has a yellowness of less than 3.0. [9] The optical film as described in [7] or [8] above, which has a total light transmittance of 90% or more. [10] The optical film described in any one of [7] to [9] above, which has an elastic modulus of 5.0 GPa or more. [11] The optical film described in any one of [7] to [10] above, which is a film for a front panel of a flexible display device. [12] A flexible display device including the optical film described in any one of [7] to [11] above. [13] The flexible display device described in [12] above, which further includes a touch sensor. [14] The flexible display device as described in [12] or [13] above, which further includes a polarizing plate. [Effects of Invention]

According to the present invention, it is possible to provide a polyamideimide resin capable of providing an optical film with high durability, and the optical film.

[式(1)及式(2)中，X及Z相互獨立地表示2價有機基，Y表示4價有機基，*表示鍵結鍵] 所表示之結構單元。[Polyamide imide resin] The polyamide imide resin of the present invention includes formula (1) and formula (2): [化6]

[In formula (1) and formula (2), X and Z independently represent a divalent organic group, Y represents a tetravalent organic group, and * represents a bonding bond].

In formula (1), Y independently represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 80 carbons, more preferably a tetravalent organic group having 4 to 60 carbons having a cyclic structure . The cyclic structure may, for example, be an alicyclic, aromatic, or heterocyclic structure. The above-mentioned organic group is an organic group that may have a substituent, and the substituent is preferably a halogen atom, a monovalent hydrocarbon group that may have a halogen atom (for example, an alkyl group, an aryl group, etc.), an alkoxy group, or an aryloxy group. The polyamide imide resin of an embodiment of the present invention may include a plurality of Y, and the plurality of Y may be the same or different from each other.

[式(3)中，R¹ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，R² ～R⁵ 相互獨立地表示氫原子或可具有鹵素原子之1價烴基，m相互獨立地表示0～3之整數，n表示1～4之整數，*表示鍵結鍵，其中，於具有R² ～R⁵ 之至少1個苯環中，R² ～R⁵ 之至少1個為可具有鹵素原子之1價烴基] 所表示之結構作為式(1)中之Y。In addition, the polyimide imine resin of the present invention includes at least the formula (3): [化7]

[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 halogen A monovalent hydrocarbon group of atoms, m independently represents an integer from 0 to 3, n represents an integer from 1 to 4, * represents a bonding bond, wherein, in at least one benzene ring ^{having R 2} to R ^{5 , R 2} At least one of ~R ⁵ is a monovalent hydrocarbon group which may have a halogen atom] The structure represented by the structure represented is as Y in the formula (1).

The inventors of the present invention found that in the polyamide imide resin containing the structural units represented by formula (1) and formula (2), Y in formula (1) includes at least the structure represented by formula (3) In this case, the durability of the optical film containing the polyimide resin is improved. The reason why the polyamide imine resin contains the structure represented by formula (3) as Y in formula (1) is not clear, but it is believed that the reason lies in: formula (3) Although the structure shown is rigid, it has side chains, so it is a structure that hinders intermolecular accumulation. By including this structure, the polyamide imide resin has a high elastic modulus and a high toughness, which further increases the stress before reaching the yield. . In addition, due to the inclusion of such a structure, the polyamideimide resin of the present invention also has excellent optical properties, and can achieve both high endurance and excellent optical properties.

In the formula (3), R ¹ independently represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group which may have a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. As the alkyl group, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, tertiary butyl, n-pentyl, 2-methyl-butyl, 3- Methylbutyl, 2-ethyl-propyl, n-hexyl, etc. As the alkoxy group, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tertiary butoxy group, a pentoxy group, a hexyloxy group, a cyclo Hexyloxy and so on. As an aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group etc. are mentioned, for example. As an aryloxy group, a phenoxy group, a naphthoxy group, a biphenoxy group, etc. are mentioned, for example. R ¹ independently of each other preferably represents a halogen atom, an alkyl group having 1 to 6 carbons which may have a halogen atom, an alkoxy group having 1 to 6 carbons, an aryl group having 6 to 12 carbons, or a carbon number of 6 to 12 of the aryloxy group.

From the standpoint that it is easy to improve the elastic modulus and transparency of an optical film containing polyimide imide resin (hereinafter, sometimes referred to as optical film), and it is easy to improve endurance, in formula (3), m is independent of each other P represents an integer of 0 to 3, preferably represents an integer of 0 to 2, more preferably represents 0 or 1, and more preferably represents 0.

In the formula (3), R ² , R ³ , R ⁴ and R ⁵ independently represent a hydrogen atom or a monovalent hydrocarbon group which may have a halogen atom. The monovalent hydrocarbon group may, for example, be an aromatic hydrocarbon group, an alicyclic hydrocarbon group, or an aliphatic hydrocarbon group. As an aromatic hydrocarbon group, aryl groups, such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, etc. are mentioned, for example. As an alicyclic hydrocarbon group, a cycloalkyl group, such as a cyclopentyl group and a cyclohexyl group, etc. are mentioned. As the aliphatic hydrocarbon group, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, tertiary butyl, n-pentyl, 2-methyl-butyl, 3 -Alkyl groups such as methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tertiary octyl, n-nonyl, n-decyl, etc. As the halogen atom, those described above may be mentioned. R ² to R ⁵ each independently preferably represent a hydrogen atom or an aryl group having 6 to 12 carbons which may have a halogen atom, a cycloalkyl group having 4 to 8 carbons, or an alkyl group having 1 to 6 carbons. From the viewpoint of easily improving the solubility of the resin in the solvent and the elastic modulus and transparency of the optical film, and easily improving the endurance of the optical film, R ² to R ⁵ independently of each other preferably represent a hydrogen atom or may have a halogen The alkyl group of the atom is more preferably a hydrogen atom or an alkyl group of 1 to 6 which may have a halogen atom, and still more preferably a hydrogen atom or an alkyl group of 1 to 3 which may have a halogen atom.

In formula (3), where R² ~R⁵ Of at least one benzene ring, R² ~R⁵ At least one of them is a monovalent hydrocarbon group which may have a halogen atom. If there is R in formula (3)² ~R⁵ Of all the benzene rings, R² ~R⁵ If the number of monovalent hydrocarbon groups that may have halogen atoms is less than one, it is difficult to sufficiently improve the endurance of the optical film, and the optical properties are also liable to decrease. In the formula (3), from the viewpoint of easily improving the endurance of the optical film and easily improving the optical properties, the R² ~R⁵ Of at least one benzene ring, R² ~R⁵ Among them, preferably 2 to 4, more preferably 3 or 4, and still more preferably 3 are monovalent hydrocarbon groups that may have halogen atoms.

From the viewpoint of easier to improve the solubility of the resin in the solvent and the endurance, breaking strain, elastic modulus and transparency of the optical film, when n is 2 or more, it is more preferable to have R ² ～R ⁵ Among the at least two benzene rings, at least one of R ² to R ⁵ is a monovalent hydrocarbon group that may have a halogen atom, and more preferably in all benzene rings ^{having R 2} to R ^{5 , R 2} to R ⁵ At least one is a monovalent hydrocarbon group which may have a halogen atom.

In formula (3), n represents an integer of 1 to 4. From the viewpoint of easily improving the endurance, elastic modulus, and transparency of the optical film, n is preferably an integer of 1 to 3, more preferably 2 or 3. More preferably, it is 2. Furthermore, the structural unit represented by the formula (1) may include one or more structures (or groups) represented by the formula (3) as Y.

[式(3')中，*表示鍵結鍵] 表示。即，於本發明之較佳實施方式中，聚醯胺醯亞胺樹脂包含式(3')所表示之結構作為式(1)中之Y。若為此種形態，則容易提高光學膜之耐力、彈性模數及透明性。In the preferred embodiment of the present invention, formula (3) is represented by formula (3'): [化8]

[In formula (3'), * represents a bonding bond] means. That is, in a preferred embodiment of the present invention, the polyimide imine resin includes the structure represented by the formula (3') as Y in the formula (1). In this form, it is easy to improve the endurance, elastic modulus, and transparency of the optical film.

In one embodiment of the present invention, in the structural unit represented by the formula (1), Y is the ratio of the structural unit of the structure represented by the formula (3) to the total mole of the structural unit represented by the formula (1) Amount (100 mol%), preferably 30 mol% or more, more preferably 35 mol% or more, still more preferably 40 mol% or more, preferably 100 mol% or less, more preferably 90 mol% Ear% or less, more preferably 80 mol% or less, and particularly preferably 70 mol% or less. If the ratio of the structural unit represented by the formula (3) of Y is more than the above-mentioned lower limit, the endurance and elastic modulus of the optical film are easily improved. Moreover, if it is below the said upper limit, it will become easy to improve the fracture strain and transparency of an optical film. The ratio of the structural unit represented by the formula (3) can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

所表示之結構作為式(1)中之Y。The polyamide imine resin of the present invention may further include formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and formula (29): [化9]

The structure shown is the Y in formula (1).

In formulas (20) to (29), * represents a bonding bond, W ¹ represents a single bond, -O-, diphenylmethylene, a divalent hydrocarbon group that may have a halogen atom (for example, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -), -Ar-, -SO ₂ -, -S-, -CO -, -PO-, -PO ₂ -, -N(R ^W1 )-or -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 arylene group having 6 to 20 carbon atoms which may have a fluorine atom, and as a specific example, a phenylene group may be mentioned. R ^W1 and R ^W2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom. Furthermore, it may be a group in which the hydrogen atom in the group represented by formula (20) to formula (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and a tetravalent carbon number 6 The following chain hydrocarbon groups. Furthermore, the hydrogen atoms on the rings in formulas (20) to (29) can also be substituted with alkyl groups with 1 to 6 carbons, alkoxy groups with 1 to 6 carbons, or aromatics with 6 to 12 carbons. base. As the alkyl group having 1 to 6 carbons, the alkoxy group having 1 to 6 carbons, and the aryl group having 6 to 12 carbons, those exemplified as R ^{1 of} the formula (3) can be exemplified, respectively.

Among the bases represented by formulas (20) to (29), in terms of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, formulas (26) and (28) are preferred Or the group represented by formula (29), more preferably the group represented by formula (26). In addition, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, 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 represents a single bond, -O-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably represents a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, and more preferably represents a single bond The bond or -C(CF ₃ ) ₂ -, particularly preferably represents -C(CF ₃ ) ₂ -.

[式(5)中，B表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-COO-、-PO-、-PO₂ -、-N(R^B1 )-或-Si(R^B2 )₂ -，R^B1 及R^B2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁷ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，t相互獨立地表示0～3之整數，*表示鍵結鍵] 表示。若聚醯胺醯亞胺樹脂進而包含式(5)所表示之結構作為式(1)中之Y，則容易提高樹脂於溶劑中之溶解性、以及光學膜之耐力及透明性。In the preferred embodiment of the present invention, the formula (26) is derived from the formula (5): [化10]

[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, and R ⁷ are mutually independent It represents a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, t represents an integer of 0 to 3 independently of each other, and * represents a bonding bond] represents. If the polyimide imine resin further contains the structure represented by formula (5) as Y in formula (1), it is easy to improve the solubility of the resin in a solvent, and the durability and transparency of the optical film.

In formula (5), R⁷ Each independently represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group which may have a halogen atom. As a halogen atom, an alkyl group, an alkoxy group, an aryl group and an aryloxy group which may have a halogen atom, respectively, the R in the formula (3) mentioned above can be exemplified¹ Exemplified. From the viewpoint of easily improving the fracture strain, elastic modulus and transparency of the optical film, R⁷ Independently from each other, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom is preferable, and an alkyl group having 1 to 3 carbon atoms which may have a halogen atom is more preferable.

In formula (5), t represents an integer of 0 to 3 independently of each other. From the viewpoint of easily improving the fracture strain, elastic modulus, and transparency of the optical film, it preferably represents an integer of 0 to 2, more preferably It represents 0 or 1, more preferably 0.

In formula (5), B 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 -, ^RB1 and ^RB2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom.

As the divalent hydrocarbon group which may have a halogen atom, among the monovalent hydrocarbon groups which may have a halogen atom among R ² to R ⁵ in the formula (3), a divalent group obtained by further removing one hydrogen atom can be mentioned. Regarding a divalent hydrocarbon group that may have a halogen atom, two hydrogen atoms of the hydrogen atoms contained in the group may be substituted to form a ring, that is, the above two hydrogen atoms are substituted into bonding bonds, and the above two bonds A ring is formed by linking together, and as this ring, a C3-12 cycloalkane ring etc. are mentioned, for example. In addition, as the alkyl group which may have a halogen atom in R ^B1 and R ^{B2 in -N(R B1} )- and -Si(R ^B2 ) ₂ -contained in B in formula (5), the above can be exemplified Here, the alkyl group which may have a halogen atom ^{in R 1} in formula (3) is exemplified.

In formula (5), from the viewpoint of easily improving the transparency, elastic modulus, and bending resistance of the optical film, B preferably represents a single bond or a divalent hydrocarbon group that may have a halogen atom, and more preferably represents a single bond , -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, and more preferably represent a single bond, -C (CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably represents a single bond or -C(CF ₃ ) ₂ -, particularly preferably represents -C(CF ₃ ) ₂ -.

[式(5')中，*表示鍵結鍵] 表示。即，聚醯胺醯亞胺樹脂較佳為包含式(5')所表示之結構作為式(1)中之Y。若為此種形態，則容易提高光學膜之透明性、彈性模數及耐彎曲性。In a preferred embodiment of the present invention, formula (5) is represented by formula (5'): [化11]

[In formula (5'), * represents a bonding bond] means. That is, the polyimide resin preferably includes the structure represented by the formula (5′) as Y in the formula (1). In this form, it is easy to improve the transparency, elastic modulus, and bending resistance of the optical film.

When the polyamide imine resin contains the structural unit represented by formula (5) in Y in formula (1), in the structural unit represented by formula (1), Y in formula (1) is the formula (5) The ratio of the structural unit of the structure represented by the formula (1) to the total molar amount (100 mol%) of the structural unit represented by the formula (1) is preferably 30 mol% or more, more preferably 35 mol% % Or more, more preferably 40 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, and still more preferably 70 mol% or less. If the ratio of the structural unit represented by the formula (5) of Y is more than the above lower limit, it is easy to improve the solubility of the resin in the solvent and the transparency of the optical film. In addition, if it is less than the above upper limit, the elastic modulus of the optical film is easily increased, and the endurance of the optical film is easily increased. Furthermore, the ratio of Y in formula (1) to the structural unit represented by formula (5) can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

In one embodiment of the present invention, when the structural unit represented by formula (5) in Y in formula (1) is included, the structural unit represented by formula (3) and Y are represented by formula (5) The total ratio of the structural units represented relative to the total molar amount of the structural units represented by formula (1) is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 90 mol% % Or more, preferably 100 mol% or less. If the total ratio is within the above range, it is easy to improve the endurance, breaking strain, elastic modulus, and transparency of the optical film. Furthermore, the total ratio can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

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

Regarding the polyamide imide resin of the present invention, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, in formula (1), X preferably contains a divalent aromatic group , At least one of a divalent alicyclic group and a divalent aliphatic group, and more preferably contains a divalent aromatic group. As the divalent aromatic group, for example, one of the hydrogen atoms in the monovalent aromatic hydrocarbon group ^{exemplified above as R 2} to R ^{5 in formula (3) is substituted with a bonding bond} from the divalent aromatic hydrocarbon group; the divalent aromatic hydrocarbon group is at least one or more via the linking group, for example below V ¹ and the like of the linking group formed by bonding group. As the divalent alicyclic group, for example, one of the hydrogen atoms in the monovalent alicyclic hydrocarbon group ^{exemplified above as R 2} to R ^{5 in formula (3) is substituted as a bond} bonded to each junction of divalent alicyclic hydrocarbon group; the divalent alicyclic hydrocarbon group of at least one or more via the linking group, for example below V ¹ and the like of the linking group formed by bonding group. As the divalent aliphatic group, for example, one of the hydrogen atoms in the monovalent aliphatic hydrocarbon group ^{exemplified above as R 2} to R ^{5 in formula (3) is substituted with a bonding bond} from the divalent aliphatic hydrocarbon group; the divalent aliphatic hydrocarbon group of at least one or more via the linking group, for example below V ¹ and the like of the linking group formed by bonding group.

In formula (1), X preferably represents a divalent organic group having a cyclic structure (alicyclic, aromatic, heterocyclic structure, etc.) having 4 to 40 carbons, and more preferably represents 2 of 4 to 40 carbons. The valence aromatic group and the divalent alicyclic group having 4 to 40 carbon atoms more preferably represent the divalent aromatic group having 4 to 40 carbon atoms. Regarding the organic group, the hydrogen atom in the organic group may be substituted with a hydrocarbyl group or a hydrocarbyl group substituted with fluorine. In this case, the carbon number of the hydrocarbyl group and the hydrocarbyl group substituted with fluorine is preferably 1-8. In one embodiment of the present invention, the polyamideimide resin of the present invention may include multiple types of X, and the multiple types of X may be the same or different from each other. Examples of X include: formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17), and formula (18) The group represented: The hydrogen atom in the group represented by the above formula (10) to formula (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group.

再者，式(10)～式(18)中之環上之氫原子亦可被取代為碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基。作為碳數1～6之烷基、碳數1～6之烷氧基及碳數6～12之芳基，分別可例舉上文中作為式(3)之R¹ 所例示者。[化12]

Furthermore, the hydrogen atoms on the rings in formulas (10) to (18) can also be substituted with alkyl groups with 1 to 6 carbons, alkoxy groups with 1 to 6 carbons, or aromatics with 6 to 12 carbons. base. As the alkyl group having 1 to 6 carbons, the alkoxy group having 1 to 6 carbons, and the aryl group having 6 to 12 carbons, those exemplified above as R ^{1 of} the formula (3) can be exemplified, respectively.

In formulas (10) to (18), * represents a bonding bond, and 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 monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms that may have a halogen atom include those exemplified above as the monovalent hydrocarbon group that may have a halogen atom among ^{R 2} to R ^{5 in 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 with respect to each ring and the bonding positions of V ² and V ³ with respect to each ring are independent of each other, and are preferably meta-position or para-position with respect to each ring, more preferably para-position.

[式(4)中，A表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R^A1 )-或-Si(R^A2 )₂ -，R^A1 及R^A2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁶ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，s相互獨立地表示0～4之整數，*表示鍵結鍵] 所表示之結構作為式(1)中之X。若為此種形態，則容易提高光學膜之耐力、斷裂應變、彈性模數及透明性。又，式(1)所表示之結構單元亦可包含1種或複數種式(4)所表示之基作為X。 In a preferred embodiment of the present invention, the polyamide imide resin of the present invention may comprise formula (4): [化 13]

[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 that may have a halogen atom, and R ⁶ independently represent a halogen atom, An alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, s each independently represents an integer of 0 to 4, and * represents a bonding bond] The structure represented is used as X in formula (1). In such a form, it is easy to improve the endurance, breaking strain, elastic modulus, and transparency of the optical film. In addition, the structural unit represented by formula (1) may include one or more types of groups represented by formula (4) as X.

In formula (4), R ⁶ independently represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group which may have a halogen atom. As a halogen atom, the alkyl group, an alkoxy group, an aryl group, and an aryloxy group which may have a halogen atom, what was exemplified above as R ¹ of formula (3) can be mentioned, respectively.

Among them, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, R ⁶ is preferably an alkyl group having 1 to 6 carbons or an alkyl group having 1 to 6 carbons independently of each other. The halogenated alkyl group is more preferably an alkyl group having 1 to 6 carbons or a fluoroalkyl group having 1 to 6 carbons (preferably a perfluoroalkyl group), and more preferably a methyl group, a chloro group or a trifluoromethyl group. s represents an integer from 0 to 4 independently of each other. From the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, it is preferably an integer of 1 to 3, more preferably 1 or 2, and further Preferably it is 1. In a preferred embodiment of the present invention, in each benzene ring, s is 1, R ⁶ is substituted at the ortho position on the basis of -A-, and R ⁶ can be methyl, fluoro, chloro or Trifluoromethyl.

In formula (4), from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, the positions of the bonding bonds are independent of each other, based on -A-, preferably meta or opposite Position, more preferably counterpoint.

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.

As the divalent hydrocarbon group which may have a halogen atom, among the monovalent hydrocarbon groups which may have a halogen atom among R ² to R ⁵ in the formula (3), a divalent group obtained by further removing one hydrogen atom can be mentioned. Regarding a divalent hydrocarbon group that may have a halogen atom, two hydrogen atoms of the hydrogen atoms contained in the group may be substituted to form a ring, that is, the above two hydrogen atoms are substituted into bonding bonds, and the above two bonds A ring is formed by linking together, and as this ring, a C3-12 cycloalkane ring etc. are mentioned, for example. In addition, as the alkyl groups that may have halogen atoms in R ^A1 and R ^{A2 of -N(R A1} )- and -Si(R ^A2 ) ₂ -contained in A in formula (4), the above can be exemplified The alkyl group which may have a halogen atom ^{in R 1} in formula (3) is exemplified.

In formula (4), from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, A preferably represents a single bond, -CH ₂ -, -CH ₂ -CH ₂ -,- CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably represents a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, More preferably, it represents a single bond or -C(CF ₃ ) ₂ -, and particularly preferably represents a single bond.

In a preferred embodiment of the present invention, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, in formula (4), R⁶ Each independently represents a halogenated alkyl group with carbon number 1 to 6, s represents 1 or 2, A represents a single bond, -C(CH₃ )₂ -Or-C(CF₃ )₂ -.

所表示。即，就容易提高光學膜之耐力、斷裂應變、彈性模數及透明性之觀點而言，聚醯胺醯亞胺樹脂較佳為包含式(4')所表示之結構作為式(1)中之X。 In the preferred form of the present invention, formula (4) is represented by formula (4'): [化14]

Represented. That is, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, the polyimide imide resin preferably includes the structure represented by the formula (4') as the formula (1) Of X.

In the structural unit represented by the formula (1), X in the formula (1) is the ratio of the structural unit of the structure represented by the formula (4) to the total molar amount of the structural unit represented by the formula (1) (100 Mol%), preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and preferably 100 mol% or less. If the ratio of the structural unit represented by X by the formula (4) is more than the above lower limit, the transparency of the optical film is easily improved. Moreover, if it is below the said upper limit, it will become easy to improve the durability of an optical film. Furthermore, the ratio of the structural units represented by the formula (4) for X in the formula (1) can ^{be measured using 1} H-NMR, or can also be calculated based on the addition ratio of the raw materials.

[式(20)～式(29)中，W¹ 表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基(例如，-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -)、-Ar-、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R^W1 )-或-Si(R^W2 )₂ -、-O-Ar-O-、-Ar-O-Ar-、-Ar-CH₂ -Ar-、-Ar-C(CH₃ )₂ -Ar-或-Ar-SO₂ -Ar-，此處，Ar相互獨立地表示可具有氟原子之碳數6～20之伸芳基(例如，伸苯基)，R^W1 及R^W2 相互獨立地表示氫原子或可具有鹵素原子之烷基，*表示鍵結鍵] 所表示之基之鍵結鍵中的不相鄰之2個鍵結鍵被取代為氫原子而成之基；及碳數6以下之2價鏈式烴基。作為具有雜環結構之2價有機基，可例舉具有噻吩環骨架之基。就容易抑制光學膜之黃度(以下，有時記作YI值)之觀點而言，較佳為：式(20)～式(29)所表示之基之鍵結鍵中的不相鄰之2個鍵結鍵被取代為氫原子而成之基；及具有噻吩環骨架之基。In formula (2), Z represents a divalent organic group, and preferably represents a divalent organic group with 4 to 40 carbons that may also have a hydrocarbon group with 1 to 8 carbons or a hydrocarbon group with 1 to 8 carbons substituted by fluorine More preferably, it represents a divalent organic group with 4 to 40 carbons and a cyclic structure that may have a hydrocarbon group with 1 to 8 carbons or a hydrocarbon group with 1 to 8 carbons substituted by fluorine. The cyclic structure may, for example, be an alicyclic, aromatic, or heterocyclic structure. As a divalent organic group having an alicyclic ring and an aromatic ring, for example: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26) ), formula (27), formula (28) and formula (29): [化15]

[In formulas (20) to (29), W ¹ represents a single bond, -O-, diphenylmethylene, or a divalent hydrocarbon group that may have a halogen atom (for example, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -), -Ar-, -SO ₂ -, -S-, -CO-, -PO- , -PO ₂ -, -N(R ^W1 )-or -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-, where Ar represents independently of each other an arylene group having 6 to 20 carbon atoms (for example, a phenylene group) which may have a fluorine atom, R ^W1 and R ^W2 independently represent a hydrogen atom or an alkyl group that may have a halogen atom, * represents a bonding bond] Two non-adjacent bonding bonds in the group represented by the group are replaced with hydrogen atoms And a divalent chain hydrocarbon group with a carbon number of 6 or less. The divalent organic group having a heterocyclic structure may, for example, be a group having a thiophene ring skeleton. From the viewpoint of easily suppressing the yellowness of the optical film (hereinafter, sometimes referred to as YI value), it is preferable that the bonding bonds of the base represented by formulas (20) to (29) are not adjacent to each other A group formed by substituting two bonding bonds with hydrogen atoms; and a group having a thiophene ring skeleton.

[式(20')～式(29')中，W¹ 及*同式(20)～式(29)中之定義] 所表示之2價有機基。再者，式(20)～式(29)及式(20')～式(29')中之環上之氫原子亦可被取代為碳數1～6之烷基、碳數1～6之烷氧基、或碳數6～12之芳基。作為碳數1～6之烷基、碳數1～6之烷氧基及碳數6～12之芳基，分別可例舉上文中作為式(3)之R¹ 所例示者。As Z in formula (2), more preferably formula (20'), formula (21'), formula (22'), formula (23'), formula (24'), formula (25'), formula ( 26'), formula (27'), formula (28') and formula (29'): [化16]

[In formula (20') to formula (29'), W ¹ and * are the same as defined in formula (20) to formula (29)] The divalent organic group represented. Furthermore, the hydrogen atoms on the ring in formulas (20) to (29) and formulas (20') to (29') can also be substituted with alkyl groups having 1 to 6 carbons, and 1 to 6 carbons. The alkoxy group, or the aryl group with 6-12 carbons. As the alkyl group having 1 to 6 carbons, the alkoxy group having 1 to 6 carbons, and the aryl group having 6 to 12 carbons, those exemplified above as R ^{1 of} the formula (3) can be exemplified, respectively.

[式(6)中，W相互獨立地表示單鍵、-O-、二苯基亞甲基、可具有鹵素原子之2價烴基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R^C1 )-或-Si(R^C2 )₂ -，R^C1 及R^C2 相互獨立地表示氫原子或可具有鹵素原子之烷基，R⁸ 相互獨立地表示鹵素原子、可具有鹵素原子之烷基、烷氧基、芳基或芳氧基，p相互獨立地表示0～4之整數，q表示0～4之整數，*表示鍵結鍵] 所表示之結構作為式(2)中之Z。若為此種形態，則容易提高光學膜之耐力、斷裂應變、彈性模數及透明性。又，式(2)所表示之結構單元亦可包含1種或複數種式(6)所表示之基作為Z。 In a preferred embodiment of the present invention, the polyamideimide resin of the present invention may comprise formula (6): [化17]

[In formula (6), W independently 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 ^C1 )- or -Si(R ^C2 ) ₂ -, R ^C1 and R ^C2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom, and R ⁸ independently represent each other A halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, p independently represents an integer from 0 to 4, q represents an integer from 0 to 4, * represents a bonding bond] The structure is the Z in formula (2). In such a form, it is easy to improve the endurance, breaking strain, elastic modulus, and transparency of the optical film. In addition, the structural unit represented by formula (2) may include one or more types of groups represented by formula (6) as Z.

In formula (6), from the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, the bonding positions of W are independent of each other, based on the bonding bond, preferably meta or pair Position, more preferably counterpoint.

[式(6')中，W、R⁸ 、p及q同式(6)中之定義] 所表示。即，本發明之聚醯胺醯亞胺樹脂較佳為包含式(6')所表示之結構作為式(2)中之Z。若為此種形態，則容易提高光學膜之耐力、斷裂應變、彈性模數及透明性。In a preferred form of the present invention, formula (6) is represented by formula (6'): [化18]

[In formula (6'), W, R ⁸ , p and q are the same as defined in formula (6)]. That is, the polyimide resin of the present invention preferably includes the structure represented by the formula (6′) as Z in the formula (2). In such a form, it is easy to improve the endurance, breaking strain, elastic modulus, and transparency of the optical film.

In formula (6) and formula (6'), R ⁸ independently represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group which may have a halogen atom. As a halogen atom, the alkyl group, an alkoxy group, an aryl group, and an aryloxy group which may have a halogen atom, what was exemplified above as R ¹ of formula (3) can be mentioned, respectively.

Among them, from the standpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, R ⁸ independently of each other preferably represents an alkyl group having 1 to 6 carbon atoms or which may have a halogen atom The alkoxy group having 1 to 6 carbons more preferably represents an alkyl group having 1 to 3 carbons or an alkoxy group having 1 to 3 carbons. p represents an integer of 0-4 independently of each other. From the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, it is preferably an integer of 0-2, more preferably 0 or 1, and further Preferably it is 0.

In formula (6) and formula (6'), W independently 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 ^C1 )- or -Si(R ^C2 ) ₂ -, from the viewpoint of easily improving the endurance, breaking strain, elastic modulus and transparency of the optical film , Preferably represents -O- or -S-, more preferably represents -O-. R ^C1 and R ^C2 independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms that may have a halogen atom include those exemplified above as the monovalent hydrocarbon group that may have a halogen atom among ^{R 2} to R ^{5 in formula (3).}

In formula (6) and formula (6'), q is an integer in the range of 0-4. If q is within this range, the endurance, breaking strain, elastic modulus, and transparency of the optical film are easily improved. Q in formula (6) and formula (6') is preferably an integer in the range of 0-3, more preferably an integer in the range of 0-2.

The structure represented by formula (6) or formula (6') where q=0 is, for example, a structure derived from terephthalic acid or isophthalic acid, and the structure is preferably formula (6) or formula (6') ) In p and q are 0 respectively, or q is 0 and p is 1 or 2 (preferably R ⁸ is an alkyl group with 1 to 3 carbons or a fluorinated alkyl group or an alkoxy group with 1 to 3 carbons ) The structure. From the viewpoint of easily improving the endurance, breaking strain, elastic modulus, and transparency of the optical film, the polyimide resin preferably contains a structural unit represented by formula (2) containing a structure derived from phthalic acid . The polyimide imine resin may also include one or more structural units represented by formula (6) or formula (6') as Z in formula (2).

In one embodiment of the present invention, when the structure represented by formula (6) is included as Z in formula (2), in the structural unit represented by formula (2), X is represented by formula (6) The ratio of the structural unit relative to the total molar amount of the structural unit represented by formula (2) is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more, Preferably it is 100 mol% or less. If the ratio of Z in the formula (2) and the structural unit represented by the formula (6) is more than the above lower limit, the endurance, breaking strain, elastic modulus, and transparency of the optical film are easily improved. If the ratio is less than the above upper limit, it is easy to suppress the increase in the viscosity of the resin varnish caused by the hydrogen bonding between the amide bonds of the formula (6), and it is easy to improve the processability of the film. Furthermore, the ratio of Z in formula (2) to the structural unit represented by formula (6) can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

In one embodiment of the present invention, when the structure represented by formula (6) is included as Z in formula (2), in the structural unit represented by formula (2), X is represented by formula (6) The ratio of the structural unit relative to the total molar amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) is preferably at least 5 mol%, more preferably at least 15 mol%, It is more preferably 30 mol% or more, more preferably 50 mol% or more, and more preferably 100 mol% or less. If the ratio of Z in the formula (2) and the structural unit represented by the formula (6) is more than the above lower limit, the endurance, breaking strain, elastic modulus, and transparency of the optical film are easily improved. If the ratio is less than the above upper limit, it is easy to suppress the increase in the viscosity of the resin varnish caused by the hydrogen bonding between the amide bonds of the formula (6), and it is easy to improve the processability of the film. Furthermore, the ratio of Z in formula (2) to the structural unit represented by formula (6) can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

[式(d1)中，R²⁴ 相互獨立地表示氫原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R²⁵ 表示R²⁴ 或-C(=O)-*，*表示鍵結鍵] 所表示之來自羧酸之結構單元。When the polyamide imide resin has a structural unit represented by any of the above-mentioned formulas (20') to (29'), Z in the formula (2), especially when it has the formula (2) In the case where Z is a structural unit represented by formula (6'), from the viewpoint that it is easy to increase the solubility of the resin and improve the processability of the resin, the polyimide imine resin is preferably divided by the formula (1 In addition to the structural units represented by the formula (2), it has the following formula (d1): [化19]

[In formula (d1), R ²⁴ independently represents a hydrogen atom, 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, and R ²⁵ represents R ²⁴ or -C(=O)-*, * represents a bonding bond] The structural unit derived from carboxylic acid represented.

In R ²⁴ , as the alkyl group with 1 to 6 carbons, the alkoxy group with 1 to 6 carbons, and the aryl group with 6 to 12 carbons, those exemplified above as R ¹ of formula (3) can be exemplified. . As the structural unit (d1), specifically, a structural unit in which R ²⁴ and R ²⁵ are both hydrogen atoms (a structural unit derived from a dicarboxylic acid compound), R ²⁴ is a hydrogen atom, and R ²⁵ represents -C( =O)-*The structural unit (the structural unit derived from the tricarboxylic acid compound) and so on.

When the polyimide imine resin contains the structural unit represented by the formula (d1), the ratio of the structural unit represented by the formula (d1) relative to the structural unit represented by the formula (1) and the structural unit represented by the formula (2) The total molar amount of the structural unit represented is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, still more preferably 1 mol% or more, preferably 30 mol% or less, more preferably 20 mol% or less, more preferably 10 mol% or less. If the ratio is within the above range, it is easy to maintain the elastic modulus of the optical film and improve the solubility of the resin. In addition, this ratio can ^{be measured using 1} H-NMR, for example, or it can also be calculated based on the addition ratio of raw materials.

As X in the formula (2), those exemplified as X in the formula (1) above can be exemplified, and preferred forms are also the same. In addition, X in formula (1) and X in formula (2) may be the same or different. In one embodiment of the present invention, the structural unit represented by formula (1) and/or the structural unit represented by formula (2) may also include one or more structures (or groups) represented by formula (4) As X.

In one embodiment of the present invention, when the structure represented by formula (4) is included as X in formula (1) and formula (2), the ratio of the structural unit represented by formula (4) to X is relative to The total molar amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% Ear% or more, preferably 100 mol% or less. If the ratio of the structural unit represented by the formula (4) of X is within the above range, the fracture strain, elastic modulus, and transparency of the optical film are easily improved, and the endurance of the optical film is easily improved. In addition, the ratio of the structural unit represented by X by the formula (4) can ^{be measured using 1} H-NMR, for example, or can be calculated based on the addition ratio of the raw materials.

In addition to the structural units represented by formula (1) and formula (2), the polyamide imine resin of the present invention may also include the structural unit represented by formula (30) and/or the structure represented by formula (31) unit. [化20]

In formula (30), Y ¹ represents a tetravalent organic group, and preferably represents an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ¹ , there can be exemplified: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) And the group represented by the formula (29); the hydrogen atom in the group represented by the above formula (20) to formula (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; And tetravalent chain hydrocarbon group with carbon number 6 or less. In one embodiment of the present invention, the formula (30) a structural unit represented by the structure may comprise a plurality of species represented by Y ^1, Y ¹ may be the same kind of a plurality of one another, also different from each other.

In formula (31), Y ² is a trivalent organic group, preferably an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ² , the above formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( 28) A group in which any one of the bonding bonds of the group represented by the formula (29) is substituted with a hydrogen atom; and a trivalent chain hydrocarbon group with 6 or less carbon atoms. In one embodiment of the present invention, the formula (31) of the structural unit represented may include a plurality of kinds of structure represented by Y ^2, a plurality of kinds of Y ² may be identical to each other, also different from each other.

In formula (30) and formula (31), X ¹ and X ² are independently a divalent organic group, preferably an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples of X ¹ and X ² include the above-mentioned formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), and formula (17) And the group represented by the formula (18); the hydrogen atom in the group represented by the formula (10) to the formula (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and Chain hydrocarbon group with carbon number 6 or less.

When the polyamide imine resin contains the structural unit represented by the formula (30) and/or the structural unit represented by the formula (31), the structural unit represented by the formula (30) and the structural unit represented by the formula (31) are The total ratio of the structural units represented is preferably 0.01 mol% or more, more preferably 0.1 mol% relative to the total molar amount of the structural units represented by the formula (1) and the structural units represented by the formula (2) Above, it is more preferably 1 mol% or more, more preferably 30 mol% or less, more preferably 20 mol% or less, and still more preferably 10 mol% or less. If the total ratio is within the above range, it is easy to obtain an optical film with a high elastic modulus. Furthermore, the ratio can be used, for example¹ It can be measured by H-NMR, or it can be calculated based on the addition ratio of the raw materials.

In the polyimide imine resin, the ratio of the structural unit represented by the formula (1) is relative to the total molar amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) (100 mol %), preferably 10 mol% or more, more preferably 15 mol% or more, still more preferably 20 mol% or more, still more preferably 25 mol% or more, particularly preferably 30 mol% or more, It is preferably 90 mol% or less, more preferably 70 mol% or less, further preferably 60 mol% or less, and particularly preferably 50 mol% or less. If the ratio of the structural units represented by the formula (1) in the polyamide imide resin is more than the above lower limit, the viscosity increase caused by the hydrogen bonds between the amide bonds in the formula (2) can be suppressed, It can reduce the viscosity of polyimide varnish, making it easy to manufacture optical components. If the ratio of the structural units represented by the formula (1) in the polyimide resin is below the above upper limit, the optical film containing the polyimide resin will exhibit high surface hardness . In addition, if the ratio of the structural unit represented by formula (1) is below the above upper limit, the ratio of the structural unit represented by formula (2) is relatively increased, thereby making it easier to increase the resin containing the polyamide imine The endurance of the optical film. In addition, the above-mentioned ratio can ^{be measured using 1} H-NMR, for example, or it can also be calculated based on the addition ratio of raw materials.

In one embodiment of the present invention, the ratio of the total amount of the structural unit represented by formula (1) and the total structural unit represented by formula (2) relative to all the structural units contained in the polyimide resin is higher than It is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, particularly preferably 90 mol% or more, and more preferably 100 mol% or less. If this ratio is more than the said lower limit, it will become easy to improve the durability and transparency of an optical film.

The weight average molecular weight (hereinafter, sometimes referred to as Mw) of the polyamideimide resin of the present invention is preferably 100,000 or more, more preferably 150,000 or more, still more preferably 200,000 or more, and even more preferably 300,000 or more, especially It is preferably 400,000 or more, particularly more preferably 500,000 or more, particularly preferably 600,000 or more, preferably 1,500,000 or less, more preferably 1,200,000 or less, still more preferably 1,000,000 or less, and particularly preferably 800,000 or less. If the Mw of the polyimide resin is more than the above lower limit, it is easy to increase the fracture strain and elastic modulus of the obtained optical film. Moreover, if Mw is less than the above upper limit value, the gelation of the resin varnish is easily suppressed, the optical properties of the obtained optical film are easily improved, and the durability of the optical film is easily improved. It can be seen here that when the polyamide imide resin of the present invention contains the structure represented by formula (3) as Y in formula (1), there is a solution of polyamide imide resin having the structure The tendency of the viscosity to become higher. As the Mw of the polyimide resin tends to increase, the viscosity of the resin solution will also increase. Therefore, it is extremely difficult to polymerize the polyimide imide resin containing such a structure. The inventors of the present invention conducted various studies and found that the Mw can be increased by producing a polyimide resin under the following production conditions. Mw can be obtained by, for example, performing gel permeation chromatography (hereinafter, sometimes referred to as GPC) measurement and conversion of standard polystyrene. For example, it can be obtained by the method described in the examples.

In a preferred embodiment of the present invention, the polyamide imide resin of the present invention may contain halogen atoms such as fluorine atoms that can be introduced using the above-mentioned fluorine-containing substituents. When the polyamideimide resin contains halogen atoms, it is easy to reduce the YI value of the optical film, and it is easy to increase the fracture strain and elastic modulus. In addition, if the elastic modulus of the optical film is high, it is easy to suppress the occurrence of damage and wrinkles. In addition, if the YI value of the optical film is low, the transparency and visibility of the film can be easily improved. The halogen atom is preferably a fluorine atom. As a fluorine-containing substituent which makes a polyamide imide resin contain a fluorine atom, for example, a fluorine group and a trifluoromethyl group can be mentioned.

Regarding the content of the halogen atom in the polyimide resin, based on the mass of the polyimide resin, it is preferably 1-40% by mass, more preferably 5-40% by mass, and more Preferably, it is 5 to 30% by mass. If the content of halogen atoms is more than the above lower limit, the YI value of the optical film is easily reduced, and the fracture strain and elastic modulus are easily increased. If the content of the halogen atom is less than the above upper limit, the synthesis is easy.

The imidization rate of the polyimide resin is preferably 90% or more, more preferably 93% or more, still more preferably 96% or more, and usually 100% or less. From the viewpoint of easy improvement of the optical properties of the optical film, the imidization rate is preferably at least the above lower limit. The imidization rate means that the molar amount of the imine bond in the polyimide imide resin is twice that of the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide imide resin. Value ratio. Furthermore, when the polyimide imide resin contains a tricarboxylic acid compound, it means that the molar amount of the imine bond in the polyimide imide resin is relative to the amount of moles in the polyimide imide resin. The ratio of the value of twice the molar amount of the structural unit of the tetracarboxylic acid compound to the total molar amount of the structural unit derived from the tricarboxylic acid compound. In addition, the imidization rate can be determined by an IR (Infrared Radiation) method, an NMR (nuclear magnetic resonance) method, or the like.

<Manufacturing method of polyimide resin> The manufacturing method of the polyimide resin of this invention is not specifically limited. In one embodiment of the present invention, the following tetracarboxylic acid compound, dicarboxylic acid compound, and diamine compound can be produced as main raw materials. More specifically, it can be produced by a method comprising the steps of: reacting a diamine compound with a tetracarboxylic acid compound to obtain polyamide; and reacting the polyamide with a dicarboxylic acid to obtain polyamide The step of amide resin precursor; and the step of imidizing the polyamide resin precursor. Furthermore, in addition to the tetracarboxylic acid compound and the dicarboxylic acid compound, a tricarboxylic acid compound may also be involved in the reaction.

The structural units represented by formula (1) and formula (30) are usually derived from diamine compounds and tetracarboxylic acid compounds. The structural unit represented by the formula (2) is usually derived from a diamine compound and a dicarboxylic acid compound. The structural unit represented by the formula (31) is usually derived from a diamine compound and a tricarboxylic acid compound.

[式(X)中，R¹ ～R⁵ 、m及n分別與式(3)中之R¹ ～R⁵ 、m及n相同] 所表示之化合物。The tetracarboxylic acid compound used in the production of the polyamide imide resin preferably contains at least the formula (X): [化21]

[In the formula ^{(X), R 1 ~ R} 5, m and n each formula R ¹ ~ R ^5, m, and n (. 3) in the same] a compound represented by the.

The compound represented by the 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.

[式(Y)中，B、R⁷ 及t分別與式(5)中之B、R⁷ 及t相同] 所表示之化合物。In one embodiment of the present invention, it is preferable that the tetracarboxylic acid compound used in the production of the polyamideimide resin further includes the formula (Y) in addition to the compound represented by the formula (X): [化22]

[In formula (Y), B, R ⁷ and t, respectively of formula (5) in the B, R ^7, and the same t] a compound represented by the.

Examples of tetracarboxylic acid compounds used in the production (or synthesis) of polyamide imide resins include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride; and aliphatic tetracarboxylic dianhydride, etc. Aliphatic tetracarboxylic acid compounds, etc. The tetracarboxylic acid compound may be used alone or in combination of two or more kinds. In addition to the dianhydride, the tetracarboxylic acid compound may be an analog of a tetracarboxylic acid compound such as a chlorine compound.

Specific examples of aromatic tetracarboxylic dianhydrides include non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic tetracarboxylic dianhydrides. Acid dianhydride. As non-condensed polycyclic aromatic tetracarboxylic dianhydrides, for example, trimellitic anhydride and 2,2',3,3',5,5'-hexamethyl-4,4'-biphenol can be cited The esterified product (hereinafter, sometimes referred to as TAHMBP), the esterified product of trimellitic anhydride and 2,2',3,3'-tetramethyl-4,4'-biphenol (hereinafter, sometimes referred to as TA23X -BP), trimellitic anhydride and 3,3',5,5'-tetramethyl-4,4'-biphenol ester, 4,4'-oxydiphthalic dianhydride, 3, 3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl Tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl 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, 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (hereinafter, sometimes referred to as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane Dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3 ,4-Dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p- Phenylenedioxy)diphthalic dianhydride, 4,4'-(isophthalic)diphthalic dianhydride. In addition, as the monocyclic aromatic tetracarboxylic dianhydride, for example, 1,2,4,5-benzenetetracarboxylic dianhydride [also referred to as pyromellitic dianhydride (hereinafter, sometimes referred to as PMDA)], as the condensed polycyclic aromatic tetracarboxylic dianhydride, for example, 2,3,6,7-naphthalenetetracarboxylic dianhydride may be mentioned.

Among these, the esterified products of TAHMBP, TA23X-BP, trimellitic anhydride and 3,3',5,5'-tetramethyl-4,4'-biphenol, PMDA, 4, 4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride Anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl 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-di Carboxyphenyl) ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis (3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(terephthalic acid) dianhydride, and 4,4'-(isophthalenedioxy)diphthalic dianhydride, more preferably exemplified by trimellitic anhydride and 2,2',3,3',5,5'-hexamethyl-4 ,4'-biphenol ester, trimellitic anhydride and 2,2',3,3'-tetramethyl-4,4'-biphenol ester, trimellitic anhydride and 3,3', 5,5'-Tetramethyl-4,4'-biphenol ester, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid Anhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 6FDA, bis(3,4-dicarboxyphenyl)methane dianhydride, and 4,4'-(p-phenylenedioxy) Diphthalic dianhydride. These can be used individually or in combination of 2 or more types.

The aliphatic tetracarboxylic dianhydride may, for example, be a cyclic or acyclic aliphatic tetracarboxylic dianhydride. Cycloaliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. As a specific example, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1 , 2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride and other cycloalkane tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7 -En-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride and their positional isomers. These can be used individually or in combination of 2 or more types. As a specific example of acyclic aliphatic tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride and 1,2,3,4-pentane tetracarboxylic dianhydride, etc. may be mentioned These can be used alone or in combination of two or more. Moreover, cycloaliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride can also be used in combination.

Among the above-mentioned tetracarboxylic dianhydrides, in terms of easily improving the durability and transparency of the optical film, trimellitic anhydride and 2,2',3,3',5,5'-hexamethyl are preferred -4,4'-biphenol ester, trimellitic anhydride and 2,2',3,3'-tetramethyl-4,4'-biphenol ester, trimellitic anhydride and 3,3 ',5,5'-Tetramethyl-4,4'-biphenol ester, PMDA, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenyl Ketonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4 ,4'-Diphenylbenzenetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 6FDA and mixtures of these, more preferably trimellitic anhydride and 2,2 ',3,3',5,5'-hexamethyl-4,4'-biphenol ester, trimellitic anhydride and 2,2',3,3'-tetramethyl-4,4' -The ester of biphenol, the ester of trimellitic anhydride and 3,3',5,5'-tetramethyl-4,4'-biphenol, 6FDA and their mixtures.

As the dicarboxylic acid compound used in the synthesis of polyamide imide resins, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and similar chlorinated compounds, acid anhydrides, etc., can be exemplified. Two kinds of Use the above. Specific examples include: terephthalic acid; 2,5-bis(trifluoromethyl)terephthalic acid; isophthalic acid; 2,5-dimethylterephthalic acid; 2,5- Dimethoxyterephthalic acid; naphthalene dicarboxylic acid; 4,4'-biphenyl dicarboxylic acid; 3,3'-biphenyl dicarboxylic acid; 2,2'-bis(trifluoromethyl)-4 ,4'-Biphenyl dicarboxylic acid; a dicarboxylic acid compound of chain hydrocarbon with carbon number 8 or less; and two benzoic acids via a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C( CF ₃ ) ₂ -, -SO ₂ -or phenylene-linked compounds; and other chlorinated compounds. Among these dicarboxylic acid compounds, 4,4'-oxybisbenzoic acid, terephthalic acid, isophthalic acid, 2- Methoxy terephthalate chloride, 2,5-dimethylterephthalic acid, 2,5-dimethoxyterephthalic acid, 2,5-bis(trifluoromethyl)terephthalic acid , 2,2'-bis(trifluoromethyl)-4,4'-biphenyl dicarboxylic acid and its chlorinated acids, more preferably 2-methoxyterephthalate chloride, 4,4' -Oxybis(benzyl chloride), 2,5-dimethylterephthalate chloride, 2,5-dimethoxyterephthalate chloride, 2,5-bis(trifluoromethyl) ) Terephthalate chloride, terephthalate chloride (hereinafter, sometimes referred to as TPC), m-phthalate chloride, more preferably TPC, 2-methoxy-terephthalate chloride, 2 ,5-Dimethylterephthalate chloride, 2,5-Dimethoxyterephthalate chloride.

Furthermore, regarding the above-mentioned polyimide resin, within the range of not damaging the various physical properties of the optical film, it may also be used in addition to the tetracarboxylic acid compound used in the synthesis of the above-mentioned polyimide resin, and in addition to other tetracarboxylic acid compounds. It is formed by the reaction of carboxylic acid, tricarboxylic acid, and their anhydrides and derivatives.

Examples of other tetracarboxylic acids include water adducts of anhydrides of the above-mentioned tetracarboxylic acid compounds.

The tricarboxylic acid compound may, for example, be aromatic tricarboxylic acid, aliphatic tricarboxylic acid, and similar chlorinated compounds, acid anhydrides, etc., and may be used in combination of two or more kinds. Specific examples include: 1,2,4-benzenetricarboxylic acid anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and benzoic acid via a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene-linked compound.

As the diamine compound used in the synthesis of the polyimide resin, for example, aliphatic diamine, aromatic diamine, and mixtures thereof can be mentioned. Furthermore, in this embodiment, "aromatic diamine" means a diamine in which an amine group is directly bonded to an aromatic ring, and an aliphatic group or other substituents may be included in a part of the structure. The aromatic ring may be a monocyclic ring or a condensed ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a sulphur ring, but are not limited to these. Among them, a benzene ring is preferred. In addition, "aliphatic diamine" means a diamine in which an amine group is directly bonded to an aliphatic group, and an aromatic ring or other substituents may be included in a part of the structure.

As aliphatic diamines, for example, acyclic aliphatic diamines such as hexamethylene diamine; and 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(amino) Cycloaliphatic diamines such as methyl)cyclohexane, noralkylene diamine and 4,4'-diaminodicyclohexylmethane, etc. These can be used individually or in combination of 2 or more types.

As aromatic diamines, for example, p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene and other aromatic diamines with one aromatic ring; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-di Aminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether Diphenyl benzene, 3,3'-diaminodiphenyl benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[ 4-(4-aminophenoxy) phenyl] chrysene, bis[4-(3-aminophenoxy) phenyl] chrysene, 2,2-bis[4-(4-aminophenoxy) )Phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl) )-4,4'-diaminobiphenyl (hereinafter, sometimes referred to as TFMB), 4,4'-(hexafluoropropylene) diphenylamine (hereinafter, sometimes referred to as 6FDAM), 4,4' -Bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)pyridium, 9,9-bis(4-amino-3-methylphenyl)pyridium, 9 , 9-bis(4-amino-3-chlorophenyl) pyrene, 9,9-bis(4-amino-3-fluorophenyl) pyrene, and other aromatic diamines with more than two aromatic rings. These can be used individually or in combination of 2 or more types.

As the aromatic diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, bis[4 -(4-Aminophenoxy) phenyl] ash, bis[4-(3-aminophenoxy) phenyl] ash, 2,2-bis[4-(4-aminophenoxy) Phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, TFMB, 4,4'-bis(4-amine Phenyloxy)biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4 '-Diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl] sulfide, 2,2-bis[4 -(4-Aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, (TFMB, 6FDAM, 4,4'-bis(4-aminophenoxy)biphenyl. The It can be used individually or in combination of 2 or more types.

Among the above-mentioned diamine compounds, it is more preferable to use 2,2'-dimethylbenzidine, TFMB, 4,4'-bis(4- One or more of the group consisting of aminophenoxy)biphenyl, 6FDAM, and 4,4'-diaminodiphenyl ether, and it is more preferable to use TFMB and/or (6FDAM).

In the production of polyimide resin, the amount of diamine compound, tetracarboxylic acid compound, and dicarboxylic acid compound used can be appropriately selected according to the ratio of each structural unit of the resin required.

In a preferred embodiment of the present invention, when the total molar amount of the tetracarboxylic acid compound and the dicarboxylic acid compound is set to 1 mol, the usage amount of the diamine compound is preferably 0.94 mol or more, more preferably 0.96 mol or more, more preferably 0.98 mol or more, particularly preferably 0.99 mol or more, preferably 1.20 mol or less, more preferably 1.10 mol or less, still more preferably 1.05 mol or less, particularly preferably 1.02 mol or less. If the usage amount of the diamine compound relative to the tetracarboxylic acid compound and the dicarboxylic acid compound is within the above range, it is easy to obtain a high molecular weight polyamide imide resin, and it is easy to improve the durability and transparency of the optical film.

The reaction temperature of the diamine compound and the tetracarboxylic acid compound is not particularly limited, and may be, for example, 5 to 200°C, and the reaction time is also not particularly limited, and may be, for example, about 30 minutes to 72 hours. In a preferred embodiment of the present invention, from the viewpoint of easily obtaining a high molecular weight polyimide resin, the reaction temperature is preferably 5-50°C, more preferably 5-40°C, and still more preferably At 5-25°C, the reaction time is preferably 3-24 hours, more preferably 5-20 hours.

The reaction of the diamine compound and the tetracarboxylic acid compound is preferably carried out in a solvent. The solvent is not particularly limited as long as it does not affect the reaction. For example, water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, Alcohol solvents such as 1-methoxy-2-propanol, 2-butoxyethanol, propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, Ester solvents such as γ-valerolactone, propylene glycol methyl ether acetate and ethyl lactate; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone, etc. Solvents; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; tetrahydrofuran and dimethoxy Ether solvents such as ethane; chlorine-containing solvents such as chloroform and chlorobenzene; N,N-dimethylacetamide (hereinafter, sometimes referred to as DMAc), N,N-dimethylformamide (hereinafter, there are DMF) and other amine-based solvents; sulfur-containing solvents such as dimethyl sulfide, dimethyl sulfide, and cyclobutyl sulfide; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and the like Combination etc. Among these, from the viewpoint of solubility, it is preferable to use an amide-based solvent.

In a preferred embodiment of the present invention, from the viewpoint of easily obtaining a high molecular weight polyimide resin, the solvent used in the reaction is preferably a solvent that is strictly dehydrated until the moisture content is 700 ppm or less.

The reaction of the diamine compound and the tetracarboxylic acid compound can also be carried out under an inert gas atmosphere such as nitrogen or argon or under reduced pressure conditions. From the viewpoint of easily obtaining a high molecular weight polyimide resin, it is preferred In order to carry out the reaction while stirring in a strictly controlled dehydration solvent under the same inert gas atmosphere as the above.

Regarding the production conditions of the polyamide acid and the dicarboxylic acid, the production conditions in the reaction of the diamine compound and the tetracarboxylic acid compound may be appropriately selected.

As the imidization catalyst used in the imidization step, for example, aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidine , N-propylpiperidine, N-butylpyrrolidine, N-butylpiperidine, and N-propyl hexahydroazepine and other alicyclic amines (monocyclic); azabicyclo[2.2.1] Heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane and azabicyclo[3.2.2]nonane and other alicyclic amines (polycyclic); and pyridine, 2 -Picoline (2-picoline), 3-picoline (3-picoline), 4-picoline (4-picoline), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, Aromatic amines such as 2,4-lutidine, 2,4,6-trimethylpyridine, 3,4-cyclopentenepyridine, 5,6,7,8-tetrahydroisoquinoline and isoquinoline . In addition, from the viewpoint of facilitating the promotion of the imidization reaction, it is preferable to use an acid anhydride together with the imidization catalyst. The acid anhydride may, for example, be a conventional acid anhydride used in an imidization reaction, and specific examples thereof may include aliphatic anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride; anhydrides of aromatic acids such as phthalic acid, and the like.

In a preferred embodiment of the present invention, it is preferable to carry out the imidization step step by step, and raise the temperature until the optimal reaction temperature. By carrying out the imidization step by step, it is easy to inhibit the decomposition of the resin, and it is easy to obtain a high molecular weight polyimide resin. In the stepwise imidization step, the reaction temperature for raising the temperature is preferably 40 to 85°C, more preferably 45 to 80°C. If the reaction temperature is within the above range, there is a tendency for the imidization reaction to proceed sufficiently, and there is a tendency for Mw to be sufficiently increased. The reaction time is preferably 30 minutes to 10 hours, more preferably 30 minutes to 5 hours. If the reaction time is within the above range, it is easy to suppress the decomposition of the resin to reduce the Mw, and it is easy to suppress the decrease in the imidization rate and decomposition into low molecules in the subsequent steps. In this way, in addition to the above-mentioned synthesis conditions, the imidization step is also controlled, whereby a high molecular weight resin can be obtained.

The polyimide resin can be separated and purified by conventional methods, such as separation methods such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography, or a combination of these separation methods, to be isolated and purified. In a preferred aspect, a large amount of methanol and other alcohols are added to the reaction liquid containing the transparent polyimide resin to precipitate the resin, and then the resin can be concentrated, filtered, dried, etc. to perform isolation.

The present invention includes an optical film containing the polyamide imide resin of the present invention. The optical film of the present invention contains a polyamide imide resin. The optical film of the present invention may include one type of polyamide resin, or two or more types of polyamide resin. The content of the polyamide imine resin in the optical film of the present invention is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and still more preferably 50 parts by mass or more with respect to 100 parts by mass of the optical film. It is preferably 99.5 parts by mass or less, and more preferably 95 parts by mass or less. If the content of the polyimide resin is within the above range, it is easy to improve the optical properties, impact resistance, elastic modulus, and endurance of the optical film.

Since the optical film of the present invention contains the above-mentioned polyimide resin, it can achieve both high durability and high transparency. Therefore, the polyimide resin and optical film of the present invention can be suitably used as materials for flexible display devices. Furthermore, in this specification, transparency can be evaluated by total light transmittance and haze, etc. Increased or improved transparency means higher total light transmittance, and/or lower haze, and/or YI The value is low.

The optical film of the present invention can show high endurance. The endurance of the optical film is preferably 90 MPa or more, more preferably 95 MPa or more, more preferably 100 MPa or more, particularly preferably 105 MPa or more, and usually 200 MPa or less. If the endurance is more than the above lower limit, it is easy to improve the bending resistance of the optical film, especially the folding resistance. Various physical properties such as elastic modulus have been studied as the physical property values that may affect the bending resistance of the optical film. According to the research of the present inventors, it is known that only by increasing the elastic modulus, sufficient resistance may sometimes not be achieved. Foldability. Therefore, in order to further improve the folding endurance, the inventors studied various physical properties and found that by improving the endurance of the optical film, the folding endurance can be sufficiently improved. In addition, the endurance can be measured with a tensile testing machine, for example, by the method described in the examples.

In a preferred embodiment of the present invention, the total light transmittance of the optical film of the present invention, preferably at a thickness of 40 μm, is preferably 85% or more, more preferably 88% or more, and more preferably It is more than 88%, more preferably 90% or more, and particularly preferably 91% or more. If the total light transmittance is more than the above lower limit, the transparency of the optical film can be improved. For example, when it is used in the front panel of a display device, it can exhibit high visibility. The upper limit of total light transmittance is usually below 100%. The optical film of the present invention generally exhibits a higher total light transmittance, and therefore, compared with the case where a film with a lower transmittance is used, for example, the luminous intensity of a display element required to obtain a certain brightness can be suppressed. Therefore, power consumption can be reduced. For example, when the optical film of the present invention is assembled into a display device, there is a tendency to obtain a bright display even if the amount of light of the backlight device is reduced, which can contribute to energy saving. In addition, the total light transmittance can be measured using a haze meter in accordance with JIS K 7105:1981, for example, it can be measured by the method described in the examples. In addition, in this specification, the total light transmittance can also be set as the total light transmittance within the thickness range of the optical film of the present invention. The total light transmittance can be the total light transmittance within the thickness range of the following optical film. Furthermore, in this specification, the excellent optical properties of the optical film means that the total light transmittance is higher, and/or the haze is lower, and/or the YI value is lower, sometimes the same as the increase or improvement of transparency. Meaning use.

In a preferred embodiment of the present invention, the haze of the optical film of the present invention, preferably at a thickness of 40 μm, is preferably 2.0% or less, more preferably 1.5% or less, and still more preferably 1.0% or less , Still more preferably 0.8% or less, particularly preferably 0.5% or less, especially more preferably 0.3% or less, and usually 0% or more. If the haze of the optical film is below the above upper limit, the transparency of the optical film can be improved. For example, when it is used in a front panel of a display device, it can exhibit high visibility. In addition, the haze can be measured using a haze meter or the like in accordance with JIS K 7136:2000, for example, it can be measured by the method described in the examples. In addition, in this specification, the haze may be within the thickness range of the following optical film.

In a preferred embodiment of the present invention, the YI value of the optical film of the present invention is preferably less than 3.0, more preferably 2.8 or less, and still more preferably 2.5 or less. If the YI value of the optical film is less than the above upper limit, the transparency of the optical film can be improved, and when it is used in the front panel of a display device, etc., it can exhibit high visibility. In addition, the yellowness is usually -5 or higher, preferably -2 or higher. Furthermore, the YI value can be calculated as follows, that is, using an ultraviolet-visible-near-infrared spectrophotometer, measuring the transmittance of light from 300 to 800 nm, and obtaining 3 stimulus values (X, Y, Z), and based on YI= 100×(1.2769X－1.0592Z)/Y formula. For example, it can be calculated by the method described in the examples.

In a preferred embodiment of the present invention, the elastic modulus of the optical film of the present invention is preferably 5.0 GPa or more, more preferably 5.5 GPa or more, still more preferably 6.0 GPa or more, and usually 15 GPa or less. If the modulus of elasticity is more than the above lower limit, the deformation of the optical film is easily suppressed and durability is easily improved. The modulus of elasticity can be measured using a tensile testing machine, for example, by the method described in the examples. Furthermore, the modulus of elasticity is the value at 25°C.

In a preferred embodiment of the present invention, the number of folds in the MIT flex fatigue test according to ASTM standard D2176-16 of the optical film of the present invention is preferably 80,000 or more, more preferably 100,000 or more, and more preferably 200,000 times or more, more preferably 250,000 times or more. If the number of folds is more than the above-mentioned lower limit, even if it is repeatedly bent, it is possible to effectively suppress the occurrence of cracks, cracks, etc. Furthermore, the MIT flex fatigue test can be measured using an MIT flex fatigue tester, for example, it can be measured by the method described in the examples.

The total light transmittance and haze vary according to the thickness of the optical film. The thicker the thickness, the lower the total light transmittance and the higher the haze. That is, it is difficult for a thicker film to be an optical film with higher total light transmittance and lower haze. On the other hand, in the preferred embodiment of the present invention, the optical film of the present invention has a high level of transparency. Therefore, even if the thickness is relatively thick, it can show higher total light transmittance and lower fog. degree. Therefore, the thickness of the optical film of the present invention is preferably 10 μm or more, more preferably 15 μm or more, still more preferably 20 μm or more, still more preferably 30 μm or more, particularly preferably 35 μm or more, especially more preferably 40 μm or more, preferably 100 μm or less, more preferably 80 μm or less, and still more preferably 60 μm or less. The thickness of the optical film can be measured with a thickness gauge or the like, and can be measured, for example, by the method described in the examples.

＜Additives＞ The optical film of the present invention may include at least one type of filler in addition to the polyimide resin. As the filler, for example, organic particles and inorganic particles may be mentioned, and preferably, inorganic particles may be mentioned. Examples of inorganic particles include metal oxide particles such as silicon dioxide, zirconium oxide, aluminum oxide, titanium dioxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide, and fluorine Metal fluoride particles such as magnesium fluoride, sodium fluoride, etc. Among them, from the viewpoint of easily improving the endurance, elastic modulus, and transparency of the optical film, silicon dioxide particles and zirconium oxide particles are preferred. , Alumina particles, more preferably silica particles. These fillers can be used alone or in combination of two or more kinds.

The average primary particle size of the filler, preferably silica particles, is usually 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, particularly preferably 20 nm or more. It is preferably 100 nm or less, more preferably 90 nm or less, still more preferably 80 nm or less, still more preferably 70 nm or less, particularly preferably 60 nm or less, especially more preferably 50 nm or less, and especially more preferably 40 Below nm. If the average primary particle size of the silica particles is within the above range, it is easy to improve the endurance, elastic modulus, and transparency of the optical film. In addition, it is easy to inhibit the aggregation of silicon dioxide particles, and it is easy to improve the transparency of the obtained optical film. The average primary particle size of the filler can be measured by the BET (Brunauer-Emmett-Teller, Buert) method. Furthermore, the average primary particle size can also be measured by image analysis of a transmission electron microscope or a scanning electron microscope.

When the optical film of the present invention contains a filler, preferably silica particles, the content of the filler relative to the mass of the optical film is usually 0.1% by mass or more, preferably 1% by mass or more, and more preferably 5% by mass % Or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, particularly preferably 30% by mass or more, and more preferably 60% by mass or less. If the content of the filler is more than the above lower limit, it is easy to improve the endurance, elastic modulus, and transparency of the optical film. Moreover, if the content of the filler is below the above upper limit, it is easy to improve the optical properties of the optical film.

The optical film of the present invention may further contain an ultraviolet absorber. The ultraviolet absorber can be appropriately selected from users who are often used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may also include a compound that absorbs light with a wavelength below 400 nm. As the ultraviolet absorber, for example, at least one compound selected from the group consisting of benzophenone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazole-based compounds may be mentioned. The ultraviolet absorber can be used alone or in combination of two or more kinds. Since the optical film contains the ultraviolet absorber, the deterioration of the resin can be suppressed, and therefore, when the optical film is applied to an image display device or the like, the visibility can be improved. In this specification, "system compound" refers to a derivative of the compound with the "system compound". For example, "benzophenone-based compound" refers to a compound having benzophenone as a parent skeleton and a substituent bonded to benzophenone.

When the optical film contains an ultraviolet absorber, the content of the ultraviolet absorber relative to the mass of the optical film is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 3% by mass or more, more preferably It is 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass or less. The preferred content varies with the ultraviolet absorber used. If the content of the ultraviolet absorber is adjusted so that the light transmittance of 400 nm becomes about 20-60%, the light resistance of the optical film can be improved, and the transparency can be easily improved.

The optical film of the present invention may further contain other additives other than fillers and ultraviolet absorbers. As other additives, for example, antioxidants, mold release agents, stabilizers, bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, tackifiers, and leveling agents may be mentioned. When other additives are contained, the content is preferably 0.001 to 20% by mass relative to the mass of the optical film, more preferably 0.01 to 15% by mass, and still more preferably 0.1 to 10% by mass.

The use of the optical film of the present invention is not particularly limited, and it can be used for various purposes. The optical film of the present invention may be a single layer or a laminate, and the optical film of the present invention may be used as it is, or another film may be laminated and used as a laminate. In addition, when the optical film is a laminated body, the laminated body including all the layers laminated on one side or both sides of the optical film is called an optical film.

When the optical film of the present invention is a laminate, it is preferable to have one or more functional layers on at least one surface of the optical film. As the functional layer, for example, a hard coat layer, an undercoat layer, a gas barrier layer, an ultraviolet absorbing layer, an adhesive layer, a hue adjustment layer, a refractive index adjustment layer, etc. may be mentioned. The functional layer can be used alone or in combination of two or more kinds.

The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. If the thickness of the hard coat layer is within the above range, there is a tendency that the impact resistance can be improved, the bending resistance is not easily reduced, and the problem of curling due to hardening shrinkage is unlikely to occur. The hard coat layer can be formed by curing a hard coat composition containing a reactive material capable of forming a crosslinked structure by irradiation with active energy rays or by imparting thermal energy, and is preferably obtained by irradiation with active energy rays. Active energy rays are defined as energy rays that can decompose compounds that produce active species to produce active species. Examples include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, and electron beams. Take ultraviolet rays as an example. The above-mentioned hard coating composition contains at least one polymer of a radical polymerizable compound and a cation polymerizable compound.

The above-mentioned radically polymerizable compound is a compound having a radically polymerizable group. The radical polymerizable group possessed by the above radical polymerizable compound may be a functional group capable of generating a radical polymerization reaction, and a group containing a carbon-carbon unsaturated double bond can be mentioned. Specifically, A vinyl group, a (meth)acryloyl group, etc. can be mentioned. Furthermore, when the above-mentioned radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different from each other. In terms of increasing the hardness of the hard coat layer, the number of the radical polymerizable groups that the radical polymerizable compound has in one molecule is preferably 2 or more. As the above-mentioned radically polymerizable compound, in terms of improving reactivity, a compound having a (meth)acryloyl group is preferably exemplified. Specifically, it may be exemplified as having 2 to 6 ( (Meth)acrylic acid compound called multifunctional acrylate monomer, and called epoxy (meth)acrylate, polyurethane (meth)acrylate, polyester (meth)acrylic acid The ester is an oligomer with several (meth)acrylic acid groups in the molecule and a molecular weight of several hundred to several thousand, preferably selected from epoxy (meth)acrylate and polyurethane One or more of (meth)acrylate and polyester (meth)acrylate.

The above-mentioned cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. In terms of increasing the hardness of the hard coat layer, the number of cationically polymerizable groups contained in the above-mentioned cationically polymerizable compound per molecule is preferably 2 or more, more preferably 3 or more. In addition, as the above-mentioned cationically polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group is particularly preferred. In terms of small shrinkage accompanying the polymerization reaction, cyclic ether groups such as epoxy groups and oxetanyl groups are preferred. In addition, the compound having the epoxy group in the cyclic ether group has the following advantages: it is easy to obtain compounds of various structures, does not adversely affect the durability of the obtained hard coat layer, and is easy to control and free radically polymerizable compounds. The compatibility. In addition, the oxetanyl group in the cyclic ether group has the following advantages: Compared with the epoxy group, the degree of polymerization is easily increased, and the formation speed of the network structure obtained from the cation polymerizable compound of the hard coat layer is accelerated. , Even in the region where the radical polymerizable compound is mixed, no unreacted monomer will remain in the film, forming an independent network structure. As the cationic polymerizable compound having an epoxy group, for example, polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or by using a compound containing a cyclohexene ring and a cyclopentene ring with hydrogen peroxide The alicyclic epoxy resin obtained by epoxidizing suitable oxidizing agents such as peracid, etc.; aliphatic polyols, or polyglycidyl ethers of their alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, Aliphatic epoxy resins such as homopolymers and copolymers of (meth)glycidyl acrylate; added by bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or their alkylene oxides Glycidyl ethers, novolac epoxy resins, etc., which are produced by the reaction of derivatives, such as caprolactone adducts, and epichlorohydrin, that is, glycidyl ether type epoxy resins derived from bisphenols.

The above-mentioned hard coat composition may further contain a polymerization initiator. The polymerization initiator may, for example, be a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, etc., and they can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate free radicals or cations to cause radical polymerization and cationic polymerization to proceed. The radical polymerization initiator may release a substance that initiates radical polymerization by at least any one of active energy ray irradiation and heating. For example, as the thermal radical polymerization initiator, organic peroxides such as hydrogen peroxide and perbenzoic acid; azo compounds such as azobisbutyronitrile and the like can be mentioned. As active energy ray radical polymerization initiators, there are Type1 radical polymerization initiators that generate free radicals by the decomposition of molecules, and those that coexist with tertiary amines to generate free radicals by hydrogen abstraction reaction. Type 2 radical polymerization initiators can be used alone or together. The cationic polymerization initiator may release a substance that initiates cationic polymerization by at least one of active energy ray irradiation and heating. As the cationic polymerization initiator, aromatic iodonium salts, aromatic sulfonium salts, cyclopentadienyl iron (II) complexes, and the like can be used. Depending on the structure, it is possible to start cationic polymerization by either active energy ray irradiation or heating, or both active energy ray irradiation or heating can start cationic polymerization.

The polymerization initiator may preferably contain 0.1 to 10% by mass relative to 100% by mass of the entire hard coating composition. If the content of the polymerization initiator is within the above range, the curing can be fully performed, and the mechanical properties or adhesion of the finally obtained coating film can be in a good range, and there is less adhesion due to curing shrinkage. Defects or cracking phenomenon and tendency to curl phenomenon.

The above-mentioned hard coating composition may further include one or more selected from the group consisting of solvents and additives. As long as the above-mentioned solvent can dissolve or disperse the above-mentioned polymerizable compound and polymerization initiator, and is a solvent widely known in the technical field as a solvent for hard coating compositions, it can be used within a range that does not hinder the effects of the present invention. . The above-mentioned additives may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

The ultraviolet absorbing layer is a layer with ultraviolet absorbing function, for example, it is composed 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 .

The adhesive layer is a layer with adhesive function, and has the function of adhering the optical film to other components. As the forming material of the adhesive layer, generally known ones can be used. For example, a thermosetting resin composition or a photocuring resin composition can be used. In this case, by supplying energy afterwards, the resin composition can be polymerized and hardened.

The adhesive layer may also be a layer called a Pressure Sensitive Adhesive (PSA) that is attached to an object by pressing. Pressure-sensitive adhesives can be used as "substances that are adhesive at room temperature and adhere to the material to be adhered with a lighter pressure" (JIS K 6800), or can be used as "in the protective film (microcapsules)" It is a capsule type adhesive agent that contains specific ingredients and can maintain stability before the film is destroyed by appropriate methods (pressure, heat, etc.)" (JIS K 6800).

The hue adjustment layer is a layer with a hue adjustment function, and is a layer that can adjust the optical film to the target hue. The hue adjusting layer is, for example, a layer containing resin and coloring agent. As the colorant, for example, inorganic pigments such as titanium oxide, zinc oxide, red lead, titanium oxide-based calcined pigments, ultramarine blue, cobalt aluminate, and carbon black; azo-based compounds, quinacridone-based compounds, Organic pigments such as anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, anthracene-based compounds, and diketopyrrolopyrrole-based compounds; barium sulfate and calcium carbonate, etc. Pigments; and dyes such as basic dyes, acid dyes and mordant dyes.

The refractive index adjustment layer is a layer having a refractive index adjustment function, and is, for example, a layer having a refractive index different from that of an optical film and capable of imparting a specific refractive index to the optical laminate. The refractive index adjustment layer may be, for example, a resin layer containing appropriately selected resin and pigments as appropriate, or a metal thin film. As the pigment for adjusting the refractive index, for example, silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide may be mentioned. The average primary particle size of the pigment may also be 0.1 μm or less. By setting the average primary particle diameter of the pigment to 0.1 μm or less, diffuse reflection of light passing through the refractive index adjustment layer can be prevented, and the decrease in transparency can be prevented. As the metal used for the refractive index adjustment layer, for example, titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, silicon nitride can be mentioned. Such as metal oxides or metal nitrides.

In one embodiment of the present invention, the optical film may also have a protective film on at least one side (single side or both sides). For example, in the case of a functional layer on a single surface of the optical film, the protective film may be laminated on the surface of the optical film side or the surface of the functional layer side, or may be laminated on both sides of the optical film side and the functional layer side. When there are functional layers on both sides of the optical film, the protective film can be laminated on the surface on the side of one functional layer or on the surface on the side of the two functional layers. The protective film is a film that temporarily protects the surface of the optical film or the functional layer, and it is not particularly limited as long as it can protect the surface of the optical film or the functional layer and can be peeled off. Examples of the protective film include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polyethylene and polypropylene films. The resin film, acrylic resin film, etc. are preferably selected from the group consisting of polyolefin resin film, polyethylene terephthalate resin film, and acrylic resin film. When the optical film has two protective films, each protective film may be the same or different.

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

[Method of manufacturing optical film] The optical film of the present invention is not particularly limited. For example, it may include the following steps: (a) A step of preparing a liquid (sometimes called a resin varnish) containing the above-mentioned polyamide imine resin (a varnish preparation step); (b) the step of coating the resin varnish on the substrate to form a coating film (coating step); and (c) The step of drying the applied liquid (coating film) to form an optical film (optical film forming step) The method of manufacturing.

In the varnish preparation step, the polyimide resin is dissolved in a solvent, and the additives are added as necessary and stirred and mixed, thereby preparing a resin varnish.

The solvent used in the preparation of the resin varnish is not particularly limited as long as it can dissolve the above-mentioned resin. Examples of the solvent include: amide-based solvents such as DMAc and DMF; lactone-based solvents such as γ-butyrolactone and γ-valerolactone; dimethyl sulfide, dimethyl sulfide, cyclobutyl sulfide, etc. Sulfur-containing solvents; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof. Among these, an amide-based solvent or a lactone-based solvent is preferred. These solvents can be used alone or in combination of two or more kinds. In addition, the resin 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 1 to 25% by mass, more preferably 5 to 15% by mass. Furthermore, in this specification, the solid content of the varnish means the total amount of the components after removing the solvent from the varnish.

In the coating step, a varnish is coated on the substrate by a well-known coating method to form a coating film. As well-known coating methods, for example, roll coating methods such as wire bar coating, reverse coating, and gravure coating, die nozzle coating methods, comma coating methods, and lip coating methods can be mentioned. , Spin coating method, screen coating method, spray coating method, dipping method, spray method, casting method, etc.

In the optical film forming step, after the coating film is dried, it is peeled from the substrate, whereby an optical film can be formed. After peeling, a step of drying the optical film can be further provided. The drying of the coating film can usually be carried out at a temperature of 50 to 350°C, preferably 50 to 230°C. In a preferred embodiment of the present invention, it is preferable to perform drying stepwise. Varnishes containing high molecular weight resins tend to have high viscosity, it is usually difficult to obtain a uniform film, and it is difficult to obtain a film with excellent transparency. Therefore, by stepwise drying, the varnish containing the high molecular weight resin can be dried uniformly. The coating film can be dried in an inert gas atmosphere or under reduced pressure as needed. In addition, if the optical film is dried under vacuum conditions, minute bubbles may be generated and left in the film, resulting in degradation of optical properties. Therefore, it is preferable to dry the optical film under atmospheric pressure.

Examples of substrates include PET (polyethylene terephthalate) film, PEN (polyethylene naphthelate, polyethylene naphthalate) film, other polyimide resins or polyamides. Series resin film, etc. Among them, from the viewpoint of excellent heat resistance, a PET film, a PEN film, etc. are preferred, and from the viewpoint of adhesion to an optical film and cost, a PET film is more preferred.

The optical film of the present invention can be used as a display device, especially a front panel of a flexible display device (sometimes called a window film), especially a front panel of a rollable display or a foldable display. That is, the optical film of the present invention is preferably a film for a front panel of a flexible display device. The front panel has the function of protecting the display elements of the flexible display device. Furthermore, the flexible display device refers to a display device used in conjunction with operations such as repeated bending and repeated winding of the image display device. For the front panel of the flexible display device used with repeated bending operations and the like, high bending resistance, especially folding resistance, is required. Moreover, for the front panel, high visibility is also required. Compared with the film for the substrate of the image display device used inside the image display device, the front panel of the image display device, especially the film for the front panel of the flexible display device, requires higher visibility and requires more High bending resistance. For example, from the viewpoint of easily improving the visibility when used in the front panel of a flexible display device, the film of the present invention preferably has the total light transmittance, haze and/or YI value as described above, In addition, from the viewpoint that it is easy to improve the bending resistance, especially the bending resistance, when used as a front panel of a flexible display device, it is preferable to satisfy the bending resistance in the MIT bending fatigue test described above. . Examples of display devices include TVs, smart phones, mobile phones, car navigation, tablet PCs (personal computers), portable game consoles, electronic paper, gauges, indicator boards, clocks, and smart watches And other wearable devices. As a flexible display, a display device with flexible characteristics can be mentioned, for example, a TV, a smart phone, a mobile phone, a smart watch, etc. As the flexible display device, all image display devices having flexibility can be mentioned, for example, a rollable display or a foldable display as described above can be mentioned. A rollable display is an image display device that includes the image display part of the front panel and is wound in a roll shape, and the image display part is pulled out to make it into a flat or curved state and used, such as every time it is used Both are image display devices that perform operations such as winding in a reel. 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 make it into a flat or curved state. It is used every time it is used. Image display device for bending and other operations. An image display device that repeatedly performs operations such as winding and bending is called a flexible display device.

[Flexible display device] The present invention includes a flexible display device provided with the optical film of the present invention. The optical film of the present invention is preferably used as a front panel in a flexible display device, and the front panel is sometimes called a window film. The flexible display device includes a laminate for a flexible display device and an organic EL display panel, and the laminate for a flexible display device is arranged on the visible side of the organic EL display panel, and is configured to be bendable. As a laminate for a flexible display device, it may further include a polarizing plate and a touch sensor. The order of the layers is arbitrary, and it is preferable to laminate the window film, the polarizing plate, and the touch sensor in order from the viewing side Mirror or window film, touch sensor, polarizing plate. If the polarizer is on the side that is more visible than the touch sensor, it is difficult to see the pattern of the touch sensor, and the visibility of the displayed image becomes better, which is better. Each member can be laminated using adhesives, adhesives, etc. In addition, it may be provided with a light-shielding pattern formed on at least one surface of any layer of the window film, the polarizing plate, and the touch sensor.

＜Polarizing plate＞ As described above, the flexible display device of the present invention further includes a polarizing plate, and among them, a circular polarizing plate is preferred. The circular polarizer is a functional layer that has a function of transmitting only a right-handed circularly polarized light component or a left-handed circularly polarized light component by laminating a λ/4 retardation plate on a linear polarizer. For example, it is used to convert external light into right-handed circularly polarized light, which will be reflected by the organic EL panel and become left-handed circularly polarized light to block the outer boundary light, and only transmit the luminous component of the organic EL, thereby suppressing the influence of the reflected light And make the image easy to view. In order to achieve the circularly polarized light function, the absorption axis of the linear polarizer and the late axis of the λ/4 retardation plate must theoretically be 45°, but in practice it is 45±10°. The linear polarizing plate and the λ/4 retardation plate do not have to be laminated adjacently, as long as the relationship between the absorption axis and the slow axis satisfies the above range. It is preferable to achieve complete circular polarization at the full wavelength, but this is not necessary in practice. Therefore, the circular polarization plate in the present invention also includes an elliptical polarization plate. It is also preferable to laminate a λ/4 retardation film on the visibility side of the linear polarizer to make the emitted light circularly polarized, thereby improving the visibility in the state of wearing polarized sunglasses.

The linear polarizer is a functional layer that has the function of passing light that vibrates in the direction of the transmission axis, but blocking the polarized light of the vibrating component perpendicular to it. The above-mentioned linear polarizing plate may be a single linear polarizing element or a structure having a linear polarizing element and a protective film attached to at least one surface thereof. The thickness of the linear polarizer may be 200 μm or less, preferably 0.5-100 μm. If the thickness of the linear polarizer is within the above range, there is a tendency that the flexibility of the linear polarizer is not easily reduced.

The linear polarizing element described above may also be a film-type polarizing element manufactured by dyeing and stretching a polyvinyl alcohol (sometimes abbreviated as PVA) film. Dichroic pigments such as iodine are adsorbed on the PVA-based film aligned by stretching, or dichroic pigments are aligned by stretching while being adsorbed on PVA, thereby exhibiting polarization performance. In the manufacture of the above-mentioned film-type polarizing element, there may be additional steps such as swelling, cross-linking with boric acid, washing with aqueous solution, and drying. The stretching or dyeing step can be performed on a separate PVA-based film, or can be performed in the state of being laminated with other films such as polyethylene terephthalate. The thickness of the PVA-based film used is preferably 10-100 μm, and the above-mentioned stretching ratio is preferably 2-10 times. Furthermore, as another example of the above-mentioned polarizing element, it may be a liquid crystal coating type polarizing element formed by coating a liquid crystal polarizing composition. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The above-mentioned liquid crystalline compound only needs to have the property of exhibiting a liquid crystal state. In particular, if it has a high-order alignment state such as a smectic arrangement, it can exhibit a higher polarization performance, which is preferable. Moreover, it is preferable that the liquid crystal compound has a polymerizable functional group. The dichroic dye is a dye that is aligned together with the liquid crystal compound to exhibit dichroism, and may have a polymerizable functional group, and the dichroic dye itself may also have liquid crystallinity. Any of the compounds contained in the liquid crystal polarizing composition has a polymerizable functional group. The above-mentioned liquid crystal polarizing composition may further include a starter, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The above-mentioned liquid crystal polarizing layer can be manufactured by coating a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer. Compared with the film-type polarizing element, the liquid crystal polarizing layer can be formed into a thinner thickness, and the thickness is preferably 0.5-10 μm, more preferably 1-5 μm.

The above-mentioned alignment film can be manufactured by, for example, coating an alignment film forming composition on a substrate and imparting alignment properties by rubbing, polarized light irradiation, or the like. The aforementioned alignment film forming composition includes an alignment agent, and may further include a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like. As the above-mentioned alignment agent, for example, polyvinyl alcohols, polyacrylates, polyamides, and polyimines can be used. In the case of using an alignment agent that imparts alignment properties by polarized light irradiation, it is preferable to use an alignment agent containing a cinnamate group. The Mw of the polymer used as the above-mentioned alignment agent is, for example, about 10,000 to 1,000,000. The thickness of the above-mentioned alignment film is preferably 5 to 10,000 nm, and more preferably 10 to 500 nm in terms of sufficiently exhibiting the alignment restriction force. The liquid crystal polarizing layer may be peeled from the base material and transferred to be laminated, or the base material may be directly laminated. The above-mentioned base material also preferably functions as a transparent base material for a protective film, a phase difference plate, and a window film.

As the above-mentioned protective film, any transparent polymer film may be used, and the same materials and additives as those used for the transparent substrate of the above-mentioned window film can be used. Furthermore, it may be a coating type protective film obtained by applying and curing a cationic curing composition such as epoxy resin or a radical curing composition such as acrylate. The protective film may also optionally contain plasticizers, ultraviolet absorbers, infrared absorbers, pigments and dyes, such as coloring agents, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, antistatic agents, antistatic agents, etc. Oxidizing agent, lubricant, solvent, etc. The thickness of the protective film is preferably 200 μm or less, more preferably 1-100 μm. If the thickness of the protective film is within the above range, there is a tendency that the flexibility of the film is not easily reduced.

The above-mentioned λ/4 retardation plate is a film that provides a λ/4 retardation in a direction orthogonal to the traveling direction of incident light (in-plane direction of the film). The above-mentioned λ/4 retardation plate may be a stretched retardation plate manufactured by stretching a polymer film such as a cellulose-based film, an olefin-based film, and a polycarbonate-based film. The above-mentioned λ/4 retardation plate may optionally contain retardation modifiers, plasticizers, ultraviolet absorbers, infrared absorbers, pigments and dyes and other coloring agents, fluorescent brighteners, dispersants, heat stabilizers, Light stabilizers, antistatic agents, antioxidants, slip agents, solvents, etc. The thickness of the above-mentioned extended phase difference plate is preferably 200 μm or less, more preferably 1-100 μm. If the thickness of the extended phase difference plate is within the above-mentioned range, the flexibility of the extended phase difference plate tends to be less likely to decrease. Furthermore, as another example of the above-mentioned λ/4 retardation plate, a liquid crystal coating type retardation plate formed by applying a liquid crystal composition can be exemplified. The above-mentioned liquid crystal composition contains a liquid crystal compound showing a liquid crystal state such as nematic, cholesteric, smectic, and the like. The above-mentioned liquid crystal compound has a polymerizable functional group. The above-mentioned liquid crystal composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The said liquid crystal coating type retardation plate can be manufactured by forming a liquid crystal retardation layer by coating a hardening liquid crystal composition on a base film similarly to the said liquid crystal polarizing layer. The liquid crystal coating type retardation plate can be formed into a thinner thickness than the extension type retardation plate. The thickness of the above-mentioned liquid crystal polarizing layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm. The liquid crystal coating type retardation plate may be peeled from the base material and transferred and laminated, or the base material may be directly laminated. The above-mentioned base material also preferably functions as a transparent base material for a protective film, a phase difference plate, and a window film.

Generally, the shorter the wavelength, the greater the birefringence, and the longer the wavelength, the smaller the birefringence. In this case, the phase difference of λ/4 cannot be achieved in the entire visible light region, so it becomes λ/4 near 560 nm where the visual sensitivity is high, and the in-plane phase difference is preferably 100-180 nm, more preferably 130 Design in a way of ~150 nm. In terms of enabling good visibility, it is preferable to use a reverse-dispersion λ/4 retardation plate that uses a material having birefringence wavelength dispersion characteristics contrary to normal. As such a material, for example, the extension type retardation plate can use what is described in Japanese Patent Laid-Open No. 2007-232873, and the liquid crystal coating type retardation plate can use what is described in the Japanese Patent Laid-Open No. 2010-30979. In addition, as another method, a technique of obtaining a wide-band λ/4 retardation plate by combining with a λ/2 retardation plate is also known (for example, Japanese Patent Laid-Open No. 10-90521). The λ/2 retardation plate can also be manufactured by the same materials and methods as the λ/4 retardation plate. Any combination of the extension type retardation plate and the liquid crystal coating type retardation plate can be made thinner by using the liquid crystal coating type retardation plate. There is also known a method of laminating a positive C plate on the circular polarizing plate to improve the visibility in the oblique direction (for example, Japanese Patent Laid-Open No. 2014-224837). The positive C plate can be a liquid crystal coating type retardation plate or an extended type retardation plate. The retardation in the thickness direction of the retardation plate is preferably -200 to -20 nm, more preferably -140 to -40 nm.

[Touch Sensor] As described above, the flexible display device of the present invention preferably further includes a touch sensor. The touch sensor is used as an input mechanism. As the touch sensor, various methods such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and an electrostatic capacitance method can be exemplified, and 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 corresponding to the area on the display panel (display part) that perceives the user's touch, and the inactive area is the area corresponding to the area where the picture is not displayed (non-display part) in the display device . The touch sensor may include: a substrate with flexible characteristics; a sensing pattern formed on the active area of the substrate; each of the sensing patterns formed on the inactive area of the substrate and used to connect the sensing pattern to an external drive circuit via a pad Sensing line. As a substrate with flexible properties, the same material as the transparent substrate of the above-mentioned window film can be used.

The aforementioned sensing pattern may include a first pattern formed in the first direction and a second pattern formed in the second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer. In order to sense the touched location, each pattern must be electrically connected. The first pattern is a form in which a plurality of unit patterns are connected to each other via a joint, but the second pattern is a structure in which a plurality of unit patterns are separated from each other in the form of islands. Therefore, in order to electrically connect the second pattern, another bridge electrode is required. As the electrode used for the connection of the second pattern, a well-known transparent electrode can be used. As the material of the transparent electrode, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), cadmium tin oxide (CTO), PEDOT (poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenedioxythiophene)), carbon nanotubes (CNT), graphene, metal wires, etc., preferably ITO. These can be used individually or in mixture of 2 or more types. The metal used for the metal wire is not particularly limited. For example, silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium can be exemplified, and these can be used alone or in combination of two or more. The bridging electrode can be formed on the upper insulating layer through the insulating edge layer on the upper part of the sensing pattern, and the bridging electrode can be formed on the substrate, and the insulating layer and the sensing pattern can be formed on the bridging electrode. The above-mentioned bridge electrode may also be formed of the same material as the sensing pattern, or may be formed of molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of these. The first pattern and the second pattern must be electrically insulated, so an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joints of the first pattern and the bridging electrodes, or may be formed as a layer covering the sensing pattern. In the case of covering the layer of the sensing pattern, the bridge electrode can connect the second pattern through the contact hole formed in the insulating layer.

The above-mentioned touch sensor may further include an optical adjustment layer between the substrate and the electrode to appropriately compensate for the difference in transmittance between the patterned area and the unpatterned non-patterned area. A method of difference in light transmittance caused by difference in refractive index in the same area. The optical adjustment layer may include an inorganic insulating material or an organic insulating material. The optical adjustment layer can be formed by coating a photo-curing composition containing a photo-curing organic adhesive and a solvent on a substrate. The above-mentioned photocurable composition may further contain inorganic particles. The above-mentioned inorganic particles can be used to increase the refractive index of the optical adjustment layer. The above-mentioned photocurable organic adhesive may include copolymers of monomers such as acrylic ester monomers, styrene monomers, and carboxylic acid monomers within a range that does not impair the effects of the present invention. The aforementioned photocurable organic adhesive may also be a copolymer containing, for example, epoxy-containing repeating units, acrylate repeating units, carboxylic acid repeating units, and other repeating units that are different from each other. Examples of the above-mentioned inorganic particles include zirconia particles, titania particles, and alumina particles. The above-mentioned photocurable composition may further contain various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

[Next layer] The window film, polarizing plate, touch sensor and other layers forming the laminated body for the flexible display device, and the film members such as the linear polarizing plate and λ/4 phase difference plate constituting each layer can be bonded with an adhesive. As the adhesive, water-based adhesives, organic solvent-based, solvent-free adhesives, solid adhesives, solvent-volatile adhesives, water-based solvent-volatile adhesives, moisture-curing adhesives, and heat-curing adhesives can be used , Anaerobic curing type, active energy ray curing type adhesive, curing agent mixed type adhesive, hot melt type adhesive, pressure sensitive adhesive, pressure sensitive adhesive, rewetting type adhesive, etc. commonly used adhesives For example, 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, etc., preferably 0.01-500 μm, more preferably 0.1-300 μm. There are a plurality of adhesive layers in the above-mentioned laminate for flexible display devices, and the thickness and type of each adhesive layer may be the same or different.

As the above-mentioned water-based solvent-volatile adhesive, water-dispersed polymers such as polyvinyl alcohol-based polymers, starches and other water-soluble polymers, ethylene-vinyl acetate emulsions, styrene-butadiene emulsions, and other water-dispersed polymers can be used as the main Agent polymer. In addition to the above-mentioned main agent polymer and water, crosslinking agents, silane-based compounds, ionic compounds, crosslinking catalysts, antioxidants, dyes, pigments, inorganic fillers, organic solvents, etc. can also be formulated. When the water-based solvent-volatile adhesive is used for bonding, the water-based solvent-volatile adhesive is injected between the layers to be bonded to bond the bonded layers, and then dried to impart adhesiveness. In the case of using the above-mentioned water-based solvent-volatile adhesive, the thickness of the adhesive layer is preferably 0.01-10 μm, more preferably 0.1-1 μm. When the above-mentioned water-based solvent volatile adhesive is used for multiple layers, the thickness and type of each layer may be the same or different.

The active energy ray curable adhesive can be formed by irradiating active energy rays to harden the active energy ray curable composition containing the reactive material that forms the adhesive layer. The active energy ray hardening composition may contain at least one polymer of the same radically polymerizable compound and cationically polymerizable compound as those contained in the hard coat composition. The radical polymerizable compound can be the same compound as the radical polymerizable compound in the hard coat composition. As the above-mentioned cationically polymerizable compound, the same compound as the cationically polymerizable compound in 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 also preferable to include a monofunctional compound as a reactive diluent.

The active energy ray composition may contain a monofunctional compound to reduce the viscosity. Examples of the monofunctional compound include an acrylate-based monomer having one (meth)acrylic acid group in one molecule and a compound having one epoxy group or oxetanyl group in one molecule. For example, glycidyl (meth)acrylate and the like. The active energy ray composition may further include a polymerization initiator. The polymerization initiator may, for example, be a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, etc., and these can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate free radicals or cations to allow radical polymerization and cationic polymerization to proceed. In the description of the hard coating composition, an initiator capable of starting at least one of radical polymerization and cationic polymerization by active energy ray irradiation can be used. The active energy ray hardening composition may further include an ion scavenger, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a fluid viscosity adjuster, a plasticizer, a defoamer solvent, an additive, and a solvent. In the case where two adhesive layers are bonded by the above-mentioned active energy ray-curable adhesive, the bonding can be performed by applying the above-mentioned active energy ray-curing composition to any one of the layers to be bonded Or after both, bonding is performed, and either one of the bonded layers or both of the bonded layers is irradiated with active energy rays to harden them. In the case of using the above-mentioned active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.01-20 μm, more preferably 0.1-10 μm. When the active energy ray-curable adhesive is used to form a plurality of adhesive layers, the thickness and type of each layer may be the same or different.

The above-mentioned adhesives can be classified into acrylic adhesives, urethane-based adhesives, rubber-based adhesives, silicone-based adhesives, etc. according to the main agent polymer, and any of them can be used. In addition to the main agent polymer, the adhesive can also be blended with crosslinking agents, silane-based compounds, ionic compounds, crosslinking catalysts, antioxidants, adhesion imparting agents, plasticizers, dyes, pigments, inorganic fillers, etc. The components constituting the adhesive are dissolved and dispersed in a solvent to obtain an adhesive composition, and the adhesive composition is applied on a substrate and then dried to form an adhesive layer or an adhesive layer. The adhesive layer can be directly formed, or it can be transferred to a substrate formed separately. In order to cover the adhesive surface before bonding, it is also preferable to use a release film. In the case of using the above-mentioned active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.1 to 500 μm, more preferably 1 to 300 μm. When the above-mentioned adhesive is used in multiple layers, the thickness and type of each layer may be the same or different.

[Shading Pattern] The above-mentioned light-shielding pattern can be used as at least a part of the bezel or housing of the above-mentioned flexible display device. The light-shielding pattern is used to hide the wiring arranged at the edge of the flexible display device to make it difficult to be seen, thereby improving the visibility of the image. The above-mentioned light-shielding pattern may be in the form of a single layer or a multiple layer. The color of the shading pattern is not particularly limited, and can be various colors such as black, white, and metallic. The light-shielding pattern can be formed by pigments used to present colors and polymers such as acrylic resins, ester resins, epoxy resins, polyurethanes, and silicones. These can be used alone or in the form of a mixture of two or more kinds. The above-mentioned light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light-shielding pattern is usually 1-100 μm, preferably 2-50 μm. Moreover, it is also preferable to give a shape such as an inclination in the thickness direction of the light-shielding pattern. [Example]

Hereinafter, the present invention will be explained more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. First, the measurement and evaluation methods will be described.

＜Endurance＞ The "Autograph AG-IS" manufactured by Shimadzu Corporation (Stock) was used to measure the endurance of the optical films obtained in the Examples and Comparative Examples. In more detail, a film with a width of 10 mm is produced, and the stress-strain line (S-S curve) is measured under the conditions of a distance between the chucks of 50 mm and a stretching speed of 10 mm/min. 1. Data sorting of S-S curve 10 points were continuously sampled from the starting point of the measurement in the S-S curve, and fitted to a quadratic function by the least square method. Then, one point is excluded from the left side of the measurement starting point, and one point on the right side is added until it becomes an upward convex shape by fitting a quadratic function of 10 points in the sampling range. At the point when the fitting function bulges upwards, the data sorting ends. 2. Calculation of the tangent equation of the S-S curve Using the n=i~j (j=2~50) data of the data in 1. above, obtain the slope and intercept by the least square method. Then, for j-1 slopes, the kth (k=1～48) to 49th data are fitted into a first-order function by the least square method, and the slope when the strain becomes 0 is obtained by extrapolation. The median value of the obtained 48 points is defined as the slope of the straight line when the strain is 0 (the tangent of the S-S curve). For the intercept, the same calculation is performed to obtain the tangent equation of the S-S curve when the strain is 0. 3. Calculation of Endurance Move the tangent line of the S-S curve obtained in 2. above to 0 when the strain is parallel to the strain direction by 0.2%. The stress value of the data whose stress measurement data exceeds the stress of the straight line of parallel movement is regarded as endurance.

＜Total light transmittance＞ According to JIS K 7105:1981, the total light transmittance (Tt) of the optical film obtained in the examples and comparative examples was measured using the automatic direct-reading haze meter HGM-2DP manufactured by Suga Test Instruments (stock).

＜Haze (Haze)＞ According to JIS K 7136:2000, the optical films obtained in the examples and comparative examples were cut into a size of 30 mm×30 mm, and the haze was measured using a haze meter ("HGM-2DP" manufactured by Suga Test Instruments Co., Ltd.) (%).

<YI value> For the optical films obtained in the examples and comparative examples, use an ultraviolet-visible-near-infrared spectrophotometer (V-670 manufactured by JASCO Corporation) to obtain the tristimulus values (X, Y, Z), Substitute into the following calculation formula to calculate the YI value. YI=100×(1.2769X－1.0592Z)/Y

＜Elastic modulus＞ The elastic modulus of the optical films obtained in the examples and comparative examples was measured using "Autograph AG-IS" manufactured by Shimadzu Corporation (stocks). A film with a width of 10 mm is made. The stress-strain line (S-S curve) is measured under the conditions of a distance between the chucks of 50 mm and a stretching speed of 10 mm/min, and the elastic modulus is calculated based on its slope.

＜Evaluation of folding endurance＞ According to ASTM standard D2176-16, the number of bending of the optical film in the examples and comparative examples is calculated as follows. Use a dumbbell cutter to cut the optical film into short strips of 15 mm×100 mm. Set the cut optical film on the body of the MIT flex fatigue tester (manufactured by Toyo Seiki Co., Ltd., model 0530), at a test speed of 175 cpm, a bending angle of 135°, a load of 0.75 kgf, and the radius of the bending jig Under the condition of R=1 mm, the number of reciprocating bending in the front and back directions before the optical film breaks is measured, and this is used as the number of bending (also called the number of resistance to bending).

＜Determination of Mw＞ GPC determination (1) Pre-treatment method To the polyimide resin obtained in the examples and comparative examples, add DMF (dimethylformamide, dimethylformamide) lysate (with 10 mmol/L of lithium bromide) at a concentration of 2 mg/mL The solution) was heated and cooled while stirring at 80°C for 30 minutes, and then filtered with a 0.45 μm membrane filter. The obtained solution was used as the measurement solution. (2) Measurement conditions Column: TSKgel α-2500 ((7)7.8 mm diameter×300 mm)×1, α-M((13)7.8 mm diameter×300 mm)×2 pieces manufactured by Tosoh Corporation Eluent: DMF (with 10 mmol/L lithium bromide) Flow rate: 1.0 mL/min Detector: RI detector Column temperature: 40℃ Injection volume: 100 μL Molecular weight standard: standard polystyrene

＜Thickness of optical film＞ An ABS digital indicator (Absolute Digimatic Indicator) ("ID-C112BS" manufactured by Mitutoyo Co., Ltd.) was used to measure the thickness of the optical films obtained in the Examples and Comparative Examples.

(Example 1) [Preparation of polyamide imide resin (1)] Under a nitrogen atmosphere, in a separable flask equipped with a stirring blade, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.13% by mass, and stir at room temperature. , While dissolving TFMB in DMAc. Then, 6FDA and TAHMBP were added to the flask so that each of them became 20.20 mol% with respect to TFMB, and the flask was stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 27.27 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 27.27 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to 6.06 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask so that they were respectively 60.61 mol%, 60.61 mol%, and 282.83 mol% relative to TFMB. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyimide resin (1). The Mw of the obtained polyimide resin (1) was 748,000.

[Manufacturing of Optical Film (1)] To the obtained polyimide resin (1), DMAc was added so that the concentration became 10% by mass to produce a polyimide resin varnish (1). Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (1) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (1) with a thickness of 40 μm.

(Example 2) [Preparation of polyamide imide resin (2)] Under nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.08% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, 6FDA and TAHMBP were added to the flask so that each of them became 20.62 mol% with respect to TFMB, and the flask was stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 27.84 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 27.84 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to make it 6.19 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask to make them 61.86 mol%, 61.86 mol%, and 288.66 mol% with respect to TFMB, respectively. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain polyimide resin (2). The Mw of the obtained polyimide resin (2) was 486,000.

[Manufacturing of Optical Film (2)] To the obtained polyimide resin (2), DMAc was added so that the concentration became 10% by mass to produce a polyimide resin varnish (2). Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (2) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (2) with a thickness of 40 μm.

(Example 3) [Preparation of polyamide imide resin (3)] Under nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.08% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, 6FDA and TAHMBP were added to the flask so that each of them became 20.62 mol% with respect to TFMB, and the flask was stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 27.84 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 27.84 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to make it 6.19 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask to make them 61.86 mol%, 61.86 mol%, and 288.66 mol% with respect to TFMB, respectively. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain polyimide resin (3). The Mw of the obtained polyimide resin (3) was 215,000.

[Manufacturing of Optical Film (3)] To the obtained polyimide resin (3), DMAc was added so that the concentration became 10% by mass to produce a polyimide resin varnish (3). Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (3) Drying at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (3) with a thickness of 40 μm.

(Example 4) [Preparation of polyamide imide resin (4)] Under nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.16% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, TAHMBP was added to the flask so that it became 30.61 mol% with respect to TFMB, and it stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 32.14 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it to 32.14 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added so as to be 7.14 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask so that they were 71.43 mol%, 71.43 mol%, and 214.29 mol% with respect to TFMB. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain polyimide resin (4). The Mw of the obtained polyimide resin (4) was 764,000.

[Manufacturing of Optical Film (4)] To the obtained polyimide resin (4), DMAc was added so that the concentration might be 10% by mass to produce a polyimide resin varnish (4). Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (4) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (4) with a thickness of 40 μm.

(Example 5) [Preparation of polyamide imide resin (5)] Under a nitrogen atmosphere, in a separable flask equipped with a stirring blade, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 4.86% by mass, and stir at room temperature. , While dissolving TFMB in DMAc. Then, TAHMBP was added to the flask so that it became 40.82 mol% with respect to TFMB, and it stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 27.55 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 27.55 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to make it 6.12 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask so that they were 61.22 mol%, 61.22 mol%, and 285.71 mol% with respect to TFMB. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyimide resin (5). The Mw of the obtained polyimide resin (5) was 613,000.

[Manufacturing of Optical Film (5)] To the obtained polyimide resin (5), DMAc was added so that the concentration became 10 mass %, and the polyimide resin varnish (5) was produced. Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (5) Drying at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (5) with a thickness of 40 μm.

(Example 6) [Preparation of polyamide imide resin (6)] Under nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to 700 ppm or less so that the solid content of TFMB becomes 5.29% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, 6FDA and TAHMBP were added to the flask so that it became 10.20 mol% and 20.41 mol% with respect to TFMB, respectively, and stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 32.14 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it to 32.14 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added so as to be 7.14 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask so that they were 71.43 mol%, 71.43 mol%, and 214.29 mol% with respect to TFMB. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain polyimide resin (6). The Mw of the obtained polyimide resin (6) was 751,000.

[Manufacturing of Optical Film (6)] To the obtained polyimide resin (6), DMAc was added so that the concentration became 10 mass %, and the polyimide resin varnish (6) was produced. Using an applicator, apply the obtained polyimide resin varnish on the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 45 μm (6) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (6) with a thickness of 40 μm.

(Comparative example 1) [Preparation of polyamide imide resin (7)] Under nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.27% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, 6FDA and the esterified product of trimellitic anhydride and 4,4'-biphenol (TA44BP) were added to the flask so that the equivalent was 20.10 mol% with respect to TFMB, and the mixture was stirred at room temperature for 16 hours. Then, after cooling to 10° C., TPC was added to make it 27.14 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it to 27.14 mol% with respect to TFMB, and stirred for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to 6.03 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask so that they were respectively 60.30 mol%, 60.30 mol%, and 281.41 mol% relative to TFMB. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was thrown into a large amount of methanol in a linear fashion, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain polyimide resin (7). The Mw of the obtained polyimide resin (7) was 139,000.

[Manufacturing of Optical Film (7)] To the obtained polyimide resin (7), DMAc was added so that the concentration became 10% by mass to produce a polyimide resin varnish (7). Using an applicator, apply the obtained polyimide resin varnish to the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 55 μm (7) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (7) with a thickness of 50 μm.

(Comparative example 2) [Preparation of polyamide imide resin (8)] Under a nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.35 mass%, and stir at room temperature. , While dissolving TFMB in DMAc. Then, 6FDA was added to the flask to make it 41.24 mol% with respect to TFMB, and it was stirred at room temperature for 16 hours. Then, after cooling to 10°C, TPC was added to make it 27.84 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 27.84 mol% with respect to TFMB, and stirring was carried out for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to make it 6.19 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, diisopropylethylamine, 4-picoline, and acetic anhydride were added to the flask to make them 61.86 mol%, 61.86 mol%, and 288.66 mol% with respect to TFMB, respectively. After stirring for 30 minutes, the internal temperature The temperature was raised to 70°C and further stirred for 3 hours to obtain a reaction liquid. The obtained reaction liquid was cooled to room temperature, the reaction liquid was linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyimide resin (8). The Mw of the obtained polyimide resin (8) was 174,000.

[Manufacturing of Optical Film (8)] To the obtained polyimide resin (8), DMAc was added so that the concentration became 10% by mass to produce a polyimide resin varnish (8). Using an applicator, apply the obtained polyimide resin varnish to the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film becomes 55 μm (8) Drying at 50°C for 30 minutes, and then at 140°C for 15 minutes, to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and then dried at 200° C. for 60 minutes to obtain an optical film (8) with a thickness of 50 μm.

(Comparative example 3) [Preparation of polyamide imide resin (9)] Under a nitrogen atmosphere, in a separable flask equipped with stirring wings, add TFMB and DMAc whose water content is strictly dehydrated to less than 700 ppm in such a way that the solid content of TFMB becomes 5.81% by mass, while stirring at room temperature , While dissolving TFMB in DMAc. Then, 6FDA was added to the flask so that it was 20.41 mol% with respect to TFMB, and it was stirred at room temperature for 16 hours. Then, after cooling to 10° C., TPC was added to make it 36.73 mol% with respect to TFMB, and after stirring for 10 minutes, TPC was further added to make it 36.73 mol% with respect to TFMB, and the mixture was stirred for 30 minutes. Then, the same amount of DMAc as the DMAc added initially was added, and after stirring for 10 minutes, TPC was added to make it 8.16 mol% relative to TFMB, and stirred for 2 hours, but the viscosity increased significantly in the middle, and the solution became agar-like. It is difficult to carry out the subsequent synthesis operation, so resin synthesis is abandoned.

For the optical films obtained in Examples 1 to 6 and Comparative Examples 1 and 2, measurements of endurance, total light transmittance, haze, YI value, and elastic modulus, and evaluation of folding endurance were performed. The results are shown in Table 1. in. In addition, Comparative Example 3 became insoluble during the synthesis, and the polyamide resin could not be synthesized, so measurement and evaluation could not be performed.

[Table 1] Endurance (MPa) Total light transmittance (%) Haze (%) YI value Modulus of Elasticity (GPa) Folding times (times) Example 1 95.4 91.4 0.3 2.44 6.24 254,000 Example 2 90.8 89.0 0.2 2.27 5.99 111,000 Example 3 90.4 89.1 0.2 2.41 6.01 107,000 Example 4 105.1 88.4 0.3 2.49 7.02 377,000 Example 5 91.6 89.1 0.3 2.55 5.43 146,000 Example 6 106.6 88.7 0.2 2.57 6.56 241,000 Comparative example 1 77.1 88.0 3.25 18.11 5.88 11,000 Comparative example 2 72.0 91.8 0.2 1.56 4.71 75,000

As shown in Table 1, it was confirmed that the optical films formed from the polyamide imide resins of Examples 1 to 6 had high durability and excellent optical properties. In contrast, it was confirmed that the optical films formed of the polyamide imide resins of Comparative Examples 1 and 2 had low durability. Therefore, it can be seen that the films formed from the polyamide imide resins of Examples 1 to 6 have high durability and excellent optical properties.

Claims (14)

A polyamide imide resin, which comprises formula (1) and formula (2): [化23]

[In formula (1) and formula (2), X and Z independently represent a divalent organic group, Y represents a tetravalent organic group, and * represents a bonding bond] The structural unit represented, and includes the formula (3): [化24]

[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 halogen A monovalent hydrocarbon group of atoms, m independently represents an integer from 0 to 3, n represents an integer from 1 to 4, * represents a bonding bond, wherein, in at least one benzene ring ^{having R 2} to R ^{5 , R 2} At least one of ~R ⁵ is a monovalent hydrocarbon group which may have a halogen atom] The structure represented by the structure represented is as Y in the formula (1). Such as the polyamide imine resin of claim 1, which contains at least one of a divalent aromatic group, a divalent alicyclic group, and a divalent aliphatic group as X in formula (1) and formula (2) . Such as the polyamide imine resin of claim 1 or 2, which comprises formula (4): [化25]

[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 that may have a halogen atom, and R ⁶ independently represent a halogen atom, An alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, s independently represents an integer of 0-4, and * represents a bonding bond] The structure represented is as formula (1) and formula (2) Among the X. Such as the polyamide imine resin of claim 1 or 2, which further comprises formula (5): [化26]

[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, and R ⁷ are mutually independent It represents a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, t independently represents an integer of 0 to 3, and * represents a bonding bond] The structure represented is as in formula (1) Of Y. Such as the polyamide imine resin of claim 1 or 2, which comprises formula (6): [化27]

[In formula (6), W independently 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 ^C1 )- or -Si(R ^C2 ) ₂ -, R ^C1 and R ^C2 independently represent a hydrogen atom or an alkyl group which may have a halogen atom, and R ⁸ independently represent each other A halogen atom, an alkyl group, an alkoxy group, an aryl group or an aryloxy group which may have a halogen atom, p independently represents an integer from 0 to 4, q represents an integer from 0 to 4, * represents a bonding bond] The structure is the Z in formula (2). For example, the polyimide resin of claim 1 or 2 has a weight average molecular weight of 100,000 or more. An optical film comprising the polyimide resin according to any one of claims 1 to 6. For example, the optical film of claim 7 has a yellowness of less than 3.0. For example, the optical film of claim 7 or 8 has a total light transmittance of 90% or more. For example, the optical film of claim 7 or 8 has an elastic modulus of 5.0 GPa or more. Such as the optical film of claim 7 or 8, which is a film for the front panel of a flexible display device. A flexible display device provided with the optical film according to any one of claims 7 to 11. For example, the flexible display device of claim 12 further includes a touch sensor. For example, the flexible display device of claim 12 or 13, which is further provided with a polarizing plate.