TW202031793A - Optical film having excellent water resistance and surface hardness and applied to a front panel material of a flexible display device - Google Patents

Abstract

The present invention provides an optical film having excellent water resistance and surface hardness, and a polyamide resin capable of forming the optical film. An optical film is formed by including polyamide resin having a structural unit expressed by formula (1). In formula (1), Ar1 represents divalent aromatic group, and the divalent aromatic group has at least one substituent selected from the group consisting of an alkyl group with 1 to 12 carbon atoms which may have a substituent, an alkoxy group with 1 to 12 carbon atoms which may have a substituent, an aryl group with 6 to 12 carbon atoms which may have a substituent, an aryloxy group with 6 to 12 carbon atoms which may have a substituent and a hydroxyl group; and Ar 2 represents a divalent aromatic group which may also have a substituent.

Description

Optical film

The present invention relates to an optical film used as a front panel material for a flexible display device, a flexible display device provided with the optical film, and a polyamide resin capable of forming the optical film.

Display devices such as liquid crystal display devices and organic EL (Electroluminescence) display devices are widely used in various applications such as mobile phones and smart watches. As the front panel of such a display device, glass was previously used, but the glass is very rigid and easy to crack, so it is difficult to be used as a front panel material such as a flexible display device. As one of the materials replacing glass, optical films containing polyamide resins have been studied (for example, Patent Document 1). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2015-521687

[The problem to be solved by the invention]

For this kind of optical film used as the front panel material of the display device, since the user will directly touch or the surrounding objects will directly contact, a higher surface hardness is required. Furthermore, the display device may be used in a high-humidity environment. Therefore, the optical film is required to have water resistance that can suppress swelling even when exposed to a high-humidity environment. However, according to the research of the present inventors, it has been found that the surface hardness and water resistance of an optical film containing a polyamide resin may be insufficient.

Therefore, the object of the present invention is to provide an optical film with excellent water resistance and surface hardness, a flexible display device provided with the optical film, and a polyamide resin capable of forming the optical film. [Technical means to solve the problem]

The inventors of the present invention made diligent studies to solve the above-mentioned problems, and as a result, they found that if an optical film includes a polyamide-based resin having at least a structural unit represented by formula (1), the above-mentioned problems can be solved and the present invention was completed. That is, the present invention includes the following preferable aspects.

[式(1)中，Ar¹ 表示二價芳香族基，該二價芳香族基具有選自由亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基、亦可具有取代基之碳數6～12之芳基、亦可具有取代基之碳數6～12之芳氧基及羥基所組成之群中之至少一個取代基，Ar² 表示亦可具有取代基之二價芳香族基]。 [2]如[1]之光學膜，其中式(1)所示之結構單元含有式(3)所示之基作為Ar¹ ， [化2]

[式(3)中，R¹ 相互獨立地表示亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基、亦可具有取代基之碳數6～12之芳基或羥基，k及n相互獨立地表示1～4之整數，於k為2以上時，於不同之芳香族基進行取代之R¹ 可相同亦可不同，*表示鍵結鍵]。 [3]如[2]之光學膜，其中於式(3)中，2個鍵結鍵相互位於對位。 [4]如[1]至[3]中任一項之光學膜，其中式(1)所示之結構單元含有式(5)所示之基作為Ar² ， [化3]

[式(5)中，R⁹ ～R¹⁶ 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，R⁹ ～R¹⁶ 中所含之氫原子亦可相互獨立地由鹵素原子取代，*表示鍵結鍵]。 [5]如[1]至[4]中任一項之光學膜，其中上述聚醯胺系樹脂進而具有式(2)所示之結構單元， [化4]

[式(2)中，Ar³ 表示具有供電子性基之二價芳香族基，Ar⁴ 及Ar⁵ 相互獨立地表示亦可具有取代基之二價芳香族基，其中，於Ar³ 與式(1)中之Ar¹ 相同且q為0時Ar⁴ 與式(1)中之Ar² 不同，W相互獨立地表示-O-、二苯基亞甲基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R²¹ )-、-Si(R²² )₂ -或碳數1～12之二價烴基，該烴基中所含之氫原子亦可相互獨立地由鹵素原子取代，亦可替換2個氫原子而形成環，R²¹ 及R²² 相互獨立地表示氫原子或亦可經鹵素原子取代之碳數1～12之一價烴基，q表示0～4之整數]。 [6]如[2]至[5]中任一項之光學膜，其中於式(3)中，R¹ 相互獨立地表示碳數1～6之烷基或碳數1～6之烷氧基，k及n相互獨立地表示1或2。 [7]如[2]至[5]中任一項之光學膜，其中於式(3)中，R¹ 相互獨立地表示碳數1～6之烷氧基，k表示1，n表示1或2。 [8]如[4]至[7]中任一項之光學膜，其中式(5)由式(6)所示， [化5]

[式(6)中，*表示鍵結鍵]。 [9]如[1]至[8]中任一項之光學膜，其中上述聚醯胺系樹脂進而具有式(5)所示之結構單元， [化6]

[式(5)中，X表示二價有機基，Y表示四價有機基]。 [10]如[1]至[9]中任一項之光學膜，其中厚度為10～200 μm。 [11]一種可撓性顯示裝置，其具備如[1]至[10]中任一項之光學膜。 [12]如[11]之可撓性顯示裝置，其進而具備觸控感測器。 [13]如[11]或[12]之可撓性顯示裝置，其進而具備偏光板。 [14]一種聚醯胺系樹脂，其至少具有式(1)所示之結構單元， [化7]

[式(1)中，Ar¹ 表示二價芳香族基，該二價芳香族基具有選自由亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基、亦可具有取代基之碳數6～12之芳基、亦可具有取代基之碳數6～12之芳氧基及羥基所組成之群中之至少一個取代基，Ar² 表示亦可具有取代基之二價芳香族基]，且 式(1)所示之結構單元含有式(3)所示之基作為Ar¹ ， [化8]

[式(3)中，R¹ 相互獨立地表示亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基、亦可具有取代基之碳數6～12之芳基或羥基，k及n相互獨立地表示1～4之整數，於k為2以上時，於不同之芳香族基進行取代之R¹ 可相同亦可不同，*表示鍵結鍵]。 [發明之效果][1] An optical film comprising a polyamide resin having at least a structural unit represented by formula (1), [化1]

[In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C1 group which may have a substituent. At least one substituent in the group consisting of an alkoxy group of 12, an aryl group of 6 to 12 carbons that may have a substituent, an aryloxy group of 6 to 12 carbons that may have a substituent, and a hydroxyl group, Ar ² represents a divalent aromatic group which may have a substituent]. [2] The optical film as in [1], wherein the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ , [化2]

[In formula (3), R ¹ independently represents an alkyl group having 1 to 12 carbons which may have a substituent, an alkoxy group having 1 to 12 carbons which may have a substituent, or a substituted An aryl group or hydroxyl group with 6 to 12 carbon atoms, k and n independently represent an integer of 1 to 4, and when k is 2 or more, R ¹ substituted for different aromatic groups may be the same or different, * means Bonding key]. [3] The optical film as in [2], wherein in the formula (3), the two bonding bonds are positioned opposite each other. [4] The optical film according to any one of [1] to [3], wherein the structural unit represented by formula (1) contains the group represented by formula (5) as Ar ² , [化3]

[In formula (5), R ⁹ to R ¹⁶ independently represent 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, R ⁹ to The hydrogen atoms contained in R ¹⁶ may be independently substituted by halogen atoms, and * represents a bonding bond]. [5] The optical film according to any one of [1] to [4], wherein the polyamide-based resin further has a structural unit represented by formula (2), [化4]

[In formula (2), Ar ³ represents a divalent aromatic group having an electron-donating group, and Ar ⁴ and Ar ⁵ independently represent a divalent aromatic group that may also have a substituent. Among them, Ar ³ and the formula Ar ¹ in (1) is the same and when q is 0, Ar ^{4 is} different from Ar ² in formula (1), and W independently represents -O-, diphenylmethylene, -SO ₂ -, -S- , -CO-, -PO-, -PO ₂ -, -N(R ²¹ )-, -Si(R ²² ) ₂ -or a divalent hydrocarbon group with 1 to 12 carbons, and the hydrogen atoms contained in the hydrocarbon group are also It can be substituted by a halogen atom independently of each other, or two hydrogen atoms can be substituted to form a ring. R ²¹ and R ²² independently represent a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms that can be substituted by a halogen atom, q Represents an integer from 0 to 4]. [6] The optical film according to any one of [2] to [5], wherein in formula (3), R ¹ independently represents an alkyl group having 1 to 6 carbons or an alkoxy group having 1 to 6 carbons The base, k and n represent 1 or 2 independently of each other. [7] The optical film according to any one of [2] to [5], wherein in formula (3), R ¹ independently represents an alkoxy group having 1 to 6 carbon atoms, k represents 1, and n represents 1 Or 2. [8] The optical film of any one of [4] to [7], wherein the formula (5) is represented by the formula (6), [化5]

[In formula (6), * represents a bonding bond]. [9] The optical film according to any one of [1] to [8], wherein the polyamide-based resin further has a structural unit represented by formula (5), [化6]

[In formula (5), X represents a divalent organic group, and Y represents a tetravalent organic group]. [10] The optical film of any one of [1] to [9], wherein the thickness is 10 to 200 μm. [11] A flexible display device including the optical film of any one of [1] to [10]. [12] The flexible display device of [11], which is further equipped with a touch sensor. [13] The flexible display device of [11] or [12], which is further provided with a polarizing plate. [14] A polyamide resin having at least a structural unit represented by formula (1), [formation 7]

[In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C1 group which may have a substituent. At least one substituent in the group consisting of an alkoxy group of 12, an aryl group of 6 to 12 carbons that may have a substituent, an aryloxy group of 6 to 12 carbons that may have a substituent, and a hydroxyl group, Ar ² represents a divalent aromatic group that may also have a substituent], and the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ , [化8]

[In formula (3), R ¹ independently represents an alkyl group having 1 to 12 carbons which may have a substituent, an alkoxy group having 1 to 12 carbons which may have a substituent, or a substituted An aryl group or hydroxyl group with 6 to 12 carbon atoms, k and n independently represent an integer of 1 to 4, and when k is 2 or more, R ¹ substituted for different aromatic groups may be the same or different, * means Bonding key]. [Effects of Invention]

The optical film of the present invention can have excellent water resistance and surface hardness. Therefore, the optical film of the present invention can be used for the front panel of a flexible display device, etc.

[Optical Film] The optical film of the present invention contains a polyamide resin having at least a specific structural unit.

[式(1)中，Ar¹ 表示二價芳香族基，該二價芳香族基具有選自由亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基、亦可具有取代基之碳數6～12之芳基、亦可具有取代基之碳數6～12之芳氧基及羥基所組成之群中之至少一個取代基，Ar² 表示亦可具有取代基之二價芳香族基] 由於該聚醯胺系樹脂具有Ar¹ 為具有特定供電子性基之二價芳香族基之式(1)所示之結構單元，故而包含該聚醯胺系樹脂而成之光學膜之耐水性及表面硬度提高。藉此，光學膜可兼具優異之耐水性與表面硬度。[Polyamide resin] The polyamide resin contained in the optical film of the present invention has at least: a structural unit represented by formula (1). [化9]

[In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C1 group which may have a substituent. At least one substituent in the group consisting of an alkoxy group of 12, an aryl group of 6 to 12 carbons that may have a substituent, an aryloxy group of 6 to 12 carbons that may have a substituent, and a hydroxyl group, Ar ² represents a divalent aromatic group which may also have a substituent] Since the polyamide-based resin has a structural unit represented by formula (1) in which Ar ¹ is a divalent aromatic group with a specific electron-donating group, it contains The water resistance and surface hardness of the optical film made of the polyamide resin are improved. Thereby, the optical film can have both excellent water resistance and surface hardness.

In this specification, the so-called polyamide resin refers to a polyamide resin as a polymer containing a repeating structural unit containing an amide group, and a polyamide resin as a repeating structural unit containing an amide group and an amide containing group. Polyimide resin that is a polymer of both repeating structural units. In addition, the repeating structural unit may be simply referred to as a structural unit in this specification.

In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C12 group which may have a substituent At least one substituent in the group consisting of the alkoxy group, the aryl group having 6 to 12 carbon atoms which may have a substituent, or the aryloxy group having 6 to 12 carbon atoms and the hydroxyl group which may have a substituent. The divalent aromatic group means a divalent monocyclic aromatic group, a divalent condensed polycyclic aromatic group, or a divalent aggregate ring aromatic group. The divalent aromatic group is preferably a divalent aromatic group having 5 to 40 carbon atoms. The polyamide resin in one embodiment of the present invention may contain one or more kinds of Ar ¹ , and the plural kinds of Ar ¹ may be the same or different from each other.

Examples of the divalent monocyclic aromatic group include: removing two carbon atoms from the monocyclic aromatic hydrocarbon ring such as a benzene ring, preferably a monocyclic aromatic hydrocarbon ring having 6 to 15 carbon atoms A divalent group derived from a hydrogen atom; a divalent group derived from the removal of two hydrogen atoms directly bonded to a carbon atom or heteroatom constituting a monocyclic aromatic heterocyclic ring, etc. The monocyclic aromatic heterocyclic ring contains at least one Heteroatoms selected from sulfur atoms, nitrogen atoms and oxygen atoms, preferably carbon and a monocyclic aromatic heterocyclic ring with 5-15 heteroatoms, such as pyridine ring, diazabenzene ring, triphenyl ring, furan Ring, thiophene ring, azole ring, diazole ring, triazole ring, azole ring, oxadiazole ring, thiazole ring, thiadiazole ring, etc.

The divalent condensed polycyclic aromatic group includes, for example, a condensed polycyclic aromatic hydrocarbon ring such as a naphthalene ring, an anthracene ring, and a phenanthrene ring, preferably a condensed polycyclic aromatic group having 10 to 25 carbon atoms. The divalent group obtained by removing 2 hydrogen atoms from the carbon atoms of the hydrocarbon ring; the divalent group obtained by removing 2 hydrogen atoms directly bonded to the carbon atoms or heteroatoms constituting the condensed polycyclic aromatic heterocycle, etc. The condensed polycyclic aromatic heterocyclic ring contains at least one heteroatom selected from sulfur atoms, nitrogen atoms and oxygen atoms, preferably carbon and a condensed polycyclic aromatic heterocyclic ring with 8 to 25 heteroatoms, such as aza Naphthalene ring, naphthyridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, dibenzosilacyclopentadiene ring, phenanthrene ring, phenanthrene ring, acridine ring, Dihydroacridine ring and so on. Furthermore, the monocyclic aromatic hydrocarbon ring and the monocyclic aromatic heterocyclic ring are collectively referred to as the monocyclic aromatic ring, and the condensed polycyclic aromatic hydrocarbon ring and the condensed polycyclic aromatic heterocyclic ring are collectively referred to as condensed polycyclic aromatic rings. Cyclic aromatic ring.

The divalent aggregate ring aromatic group means the aggregate ring aromatic ring formed by removing and forming the monocyclic aromatic ring and/or the condensed polycyclic aromatic ring connected by a single bond, preferably the number of carbon and heteroatoms is 10. ~40 A divalent group derived from two hydrogen atoms directly bonded to carbon atoms or heteroatoms of an aromatic ring. The divalent aggregate ring aromatic group may include one or more monocyclic aromatic rings, may also include one or more condensed polycyclic aromatic rings, or may be composed of a combination of these groups. Specifically, as a divalent ring-assembling aromatic group, for example, removing and constituting carbon atoms or carbon atoms constituting a ring-assembling aromatic ring such as a biphenyl ring, a bipyridine ring, a phenylnaphthalene ring, a terphenyl ring, a terpyridine ring, etc. A divalent group derived from two hydrogen atoms directly bonded to a heteroatom.

Among the divalent aromatic groups, in terms of easy improvement of surface hardness, water resistance, optical properties, elastic modulus, and yield point strain, a divalent monocyclic aromatic group or a divalent aggregate ring aromatic group is preferred , More preferably a divalent monocyclic aromatic group such as phenylene.

The divalent aromatic group in Ar ¹ of the formula (1) may have a C1-C12 alkyl group which may be substituted, and a C1-C12 alkoxy group which may also have a substituent. At least one substituent in the group consisting of a substituted aryl group having 6 to 12 carbons, an optionally substituted aryloxy group having 6 to 12 carbons and a hydroxyl group (hereinafter referred to as substituent A) ). When the divalent aromatic group has a plurality of substituents A, it may also have a plurality of substituents A that are the same or different. From the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, it is preferable to have a plurality of identical substituents A. In addition, the number of substituents A of the divalent aromatic group can be appropriately selected according to the type of the aromatic group, and is, for example, 1 to 8, preferably 1 to 6, more preferably 1 to 4, and more It is preferably 1 to 3, particularly preferably 1 or 2.

In Ar ¹ of the formula (1), the alkyl group having 1 to 12 carbon atoms includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. , N-pentyl, 2-methylbutyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, tertiary octyl, n-nonyl and n-decyl, etc. . The alkyl group having 1 to 12 carbon atoms may have a substituent (hereinafter referred to as substituent B). The substituent B is not particularly limited, and examples thereof include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; as an aromatic group having 6 to 12 carbon atoms described later The aryl group exemplified as the group; the aryloxy group exemplified as the aryloxy group having 6 to 12 carbon atoms; aralkyl groups such as benzyl; the alkoxy group as the alkoxy group having 1 to 12 carbon atoms mentioned later; Aralkyloxy such as benzyloxy; alkylthio such as methylthio and ethylthio; cycloalkylthio such as cyclohexylthio; arylthio such as phenylthio; aralkylthio such as benzylthio; acetylthio Base and other acyl; nitro; cyano, etc. Among the alkyl groups having 1 to 12 carbon atoms that may have these substituents B, from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, it is preferred An alkyl group having 1 to 6 carbon atoms which may have a substituent, more preferably an alkyl group having 1 to 4 carbon atoms which may have a substituent, and still more preferably a methyl group or an ethyl group which may also have a substituent. The alkyl group having 1 to 12 carbon atoms which may have a substituent may be used alone or in combination of two or more kinds.

In Ar ¹ of the formula (1), examples of the alkoxy group having 1 to 12 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, Tertiary butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, cyclohexyloxy Wait. The alkoxy group having 1 to 12 carbon atoms may have a substituent. The substituent is not particularly limited, and examples include the alkyl groups exemplified as the alkyl group having 1 to 12 carbon atoms; and the groups exemplified as the substituent B. Among the alkoxy groups having 1 to 12 carbon atoms that may have substituents, it is preferable to have the ability to easily improve the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film. The alkoxy group having 1 to 6 carbon atoms as the substituent is more preferably an alkoxy group having 1 to 4 carbon atoms which may have a substituent, and more preferably a methoxy group or an ethoxy group which may have a substituent. The alkoxy group having 1 to 12 carbon atoms which may have a substituent may be used alone or in combination of two or more kinds.

In Ar ¹ of the formula (1), examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenyl group. The aryl group having 6 to 12 carbon atoms may have a substituent. The substituent is not particularly limited, and examples include the alkyl groups exemplified as the alkyl group having 1 to 12 carbons; the same as the substituents other than the aryl group having 6 to 12 carbons in the above substituent B The base. Among the aryl groups having 6 to 12 carbon atoms that may have a substituent, the phenyl group is preferred from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film. The aryl group having 6 to 12 carbon atoms which may have a substituent may be used alone or in combination of two or more kinds.

In Ar ¹ of the formula (1), examples of the aryloxy group having 6 to 12 carbon atoms include a phenoxy group. The aryloxy group having 6 to 12 carbon atoms may have a substituent. The substituent is not particularly limited, and examples include the alkyl groups exemplified as the alkyl group having 1 to 12 carbon atoms; and the groups exemplified as the substituent B. The aryloxy group having 6 to 12 carbon atoms which may have a substituent may be used alone or in combination of two or more kinds.

As Ar ^{1 of the} formula (1), from the viewpoint of easily obtaining an optical film having excellent surface hardness, water resistance, optical properties, elastic modulus, and yield point strain, it is preferable to have a carbon that may have a substituent A divalent monocyclic aromatic group or a divalent aggregate ring aromatic group of an alkyl group having 1 to 12 or an alkoxy group having 1 to 12 carbons which may have a substituent; more preferably, it may have a substituent A divalent monocyclic aromatic group of an alkoxy group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

[式(3)中，R¹ 相互獨立地表示亦可具有取代基之碳數1～12之烷基、亦可具有取代基之碳數1～12之烷氧基或亦可具有取代基之碳數6～12之芳基，k及n相互獨立地表示1～4之整數，於k為2以上時，於不同之芳香族基進行取代之R¹ 可相同亦可不同，*表示鍵結鍵] 即，式(1)中之複數個Ar¹ 中，至少一部分Ar¹ 為式(3)所示之基。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數及降伏點應變。再者，式(1)所示之結構單元亦可含有1種或複數種式(3)所示之基作為Ar¹ 。In a preferred embodiment of the present invention, the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ . [化10]

[In formula (3), R ¹ independently represents an alkyl group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, or a substituted An aryl group with 6 to 12 carbon atoms, k and n each independently represent an integer of 1 to 4. When k is 2 or more, R ¹ substituted for different aromatic groups may be the same or different, and * means bonding Bond] That is, among the plurality of Ar ¹ in formula (1), at least a part of Ar ¹ is the group represented by formula (3). In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, and yield point strain. Furthermore, the structural unit represented by the formula (1) may also contain one or more groups of the groups represented by the formula (3) as Ar ¹ .

R ¹ in the formula (3) independently represents a C1-C12 alkyl group which may have a substituent, a C1-C12 alkoxy group which may have a substituent or a carbon which may have a substituent The number of aryl groups from 6 to 12. Examples of an alkyl group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, and an aryl group having 6 to 12 carbon atoms which may have a substituent include, respectively In the above formula (1), Ar ¹ is an alkyl group having 1 to 12 carbons which may have a substituent, an alkoxy group having 1 to 12 carbons which may have a substituent, and a carbon which may have a substituent Those exemplified by the number 6-12 aryl groups. Among them, in terms of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, R ¹ in formula (3) preferably represents that it may have a substituent independently of each other The alkyl group having 1 to 12 carbons or the alkoxy group having 1 to 12 carbons which may have a substituent, more preferably an alkyl group having 1 to 6 carbons or an alkoxy group having 1 to 6 carbons.

In formula (3), k and n independently represent an integer of 1 to 4, and when k is 2 or more, R ¹ substituted with different aromatic groups may be the same or different. From the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, k is preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1. n is preferably an integer of 1 to 3, more preferably 1 or 2.

In a preferred embodiment of the present invention, in formula (3), R ¹ independently represents an alkyl group having 1 to 6 carbons or an alkoxy group having 1 to 6 carbons, and k and n independently represent 1 or 2. In a more preferable embodiment of the present invention, in formula (3), R ¹ represents an alkoxy group having 1 to 6 carbon atoms, k represents 1, and n represents 1 or 2. In such a form, it is easy to obtain an optical film with further improved surface hardness, water resistance, optical properties, elastic modulus, and yield point strain.

In formula (3), although the two bonding bonds may be located at the ortho, meta, or para position to each other, they are preferably located at the para position to each other. If the two bonding bonds are positioned in the opposite position, it is advantageous in terms of surface hardness, water resistance, optical properties, elastic modulus, and yield point strain, and it is also advantageous in that it is easy to increase polymerizability and increase molecular weight.

In a preferred embodiment of the present invention, the ratio of the group represented by formula (3) contained in Ar ¹ in formula (1) to the molar amount of the structural unit represented by formula (1) is preferably It is 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the structural unit represented by formula (3) is in the above range, it is advantageous from the viewpoints of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film. The ratio of the base represented by the formula (3) can be measured using ¹ H-NMR (1H Nuclear Magnetic Resonance, Hydrogen Nuclear Magnetic Resonance Spectroscopy), or can also be calculated based on the addition ratio of the raw materials.

In a preferred embodiment of the present invention, Ar ¹ in formula (1) is the ratio of the structural unit of the base represented by formula (3) relative to the structural unit represented by formula (1) and formula (5) The total molar amount of the structural unit is preferably 10 mol% or more, more preferably 30 mol% or more, further preferably 50 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, more preferably 90 mol% or less.

Ar ² in formula (1) represents a divalent aromatic group which may have a substituent. As a divalent aromatic group, it means a divalent monocyclic aromatic group, a divalent condensed polycyclic aromatic group, or a divalent condensed ring aromatic group. Examples of the divalent aromatic group include Ar ¹ in formula (1). Those exemplified by aromatic groups. Among them, from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, a divalent aggregate ring aromatic group is preferred, and k is 2 or more. In this case, the group represented by formula (3) is more preferably a biphenylene group.

The divalent aromatic group in Ar ² of the formula (1) may have a substituent (hereinafter, it may be referred to as a substituent C). Examples of the substituent C include those similar to the above-mentioned substituent B. When the substituent B contains a hydrogen atom, the hydrogen atom may be independently substituted with a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, for example. Among these substituents C, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, an alkyl group having 1 to 6 carbons and an alkyl group having 1 to 6 carbons are preferred. Alkoxy groups of 6, aryl groups of 6 to 12 carbons, or groups in which at least a part of the hydrogen atoms contained in these groups are substituted with halogen atoms, more preferably alkyl groups of 1 to 3 carbons or among these groups The group in which at least a part of the contained hydrogen atoms is substituted with halogen atoms is more preferably a methyl group, a fluoro group, a chloro group or a trifluoromethyl group. In addition, 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, the number of carbons in R ⁹ to R ¹⁶ of formula (5) is 1 -6 alkyl groups, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons are exemplified.

[式(5)中，R⁹ ～R¹⁶ 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，R⁹ ～R¹⁶ 中所含之氫原子亦可相互獨立地由鹵素原子取代，*表示鍵結鍵] 即，式(1)中之複數個Ar² 中，至少一部分Ar² 為式(5)所示之基。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數、降伏點應變及耐彎曲性。再者，式(1)所示之結構單元亦可含有1種或複數種式(5)所示之基作為Ar² 。In a preferred embodiment of the present invention, the structural unit represented by formula (1) contains the group represented by formula (5) as Ar ² . [化11]

[In formula (5), R ⁹ to R ¹⁶ independently represent 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, R ⁹ to The hydrogen atoms contained in R ¹⁶ can also be independently substituted by halogen atoms, * represents a bonding bond] That is, among the plurality of Ar ² in formula (1), at least a part of Ar ² is represented by formula (5) base. In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. Furthermore, the structural unit represented by the formula (1) may also contain one or more groups of the group represented by the formula (5) as Ar ² .

In formula (5), R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, and a carbon number of 1 to 6 The alkoxy group or the aryl group with 6-12 carbons. Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, tertiary butyl, n-pentyl, and 2-methyl Butyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, etc. Examples of alkoxy groups having 1 to 6 carbon atoms include: methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tertiary butoxy, and pentoxy , Hexyloxy and cyclohexyloxy, etc. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, naphthyl, and biphenyl. Among these, R ⁹ to R ¹⁶ independently of each other preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbons, and more preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbons. Here, R ⁹ to R ¹⁶ The hydrogen atoms contained in can also be independently substituted by halogen atoms. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. From the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, R ⁹ to R ¹⁶ are independent of each other and are preferably hydrogen atoms, methyl groups, and fluorine atoms. Substituent, chloro or trifluoromethyl, more preferably R ⁹ , R ¹⁰ , R ¹² , R ¹⁴ , R ¹⁵ and R ¹⁶ are hydrogen atoms, and R ¹¹ and R ¹³ are hydrogen atoms, methyl or fluorine Substitute, chloro or trifluoromethyl, particularly preferably R ¹¹ and R ¹³ are methyl or trifluoromethyl.

[式(6)中，*表示鍵結鍵] 即，式(1)所示之結構單元含有式(6)所示之基作為Ar² 。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數、降伏點應變及耐彎曲性。又，藉由含有氟元素之骨架，可提高樹脂向溶劑中之溶解性，將樹脂清漆之黏度抑制為較低，且可容易地進行光學膜之加工。式(1)所示之結構單元亦可含有1種或複數種式(6)所示之基作為Ar² 。In a preferred embodiment of the present invention, formula (5) is represented by formula (6). [化12]

[In formula (6), * represents a bonding bond] That is, the structural unit represented by formula (1) contains the group represented by formula (6) as Ar ² . In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. In addition, the fluorine-containing skeleton can improve the solubility of the resin in the solvent, suppress the viscosity of the resin varnish to a low level, and can easily process the optical film. The structural unit represented by formula (1) may also contain one or more kinds of groups represented by formula (6) as Ar ² .

In a preferred embodiment of the present invention, the ratio of formula (5), especially the base represented by formula (6) contained in Ar ² in formula (1), relative to the structural unit represented by formula (1) The molar amount is preferably 30 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the formula (5) contained in the Ar ² in the formula (1), especially the base represented by the formula (6) is in the above range, it is easy to show excellent surface hardness, water resistance, optical properties, and elastic modulus. Number, yield point strain and bending resistance, and the skeleton containing fluorine elements can improve the solubility of the resin in the solvent, suppress the viscosity of the resin varnish to a low, and can easily process the optical film. The ratio of the group represented by the formula (5) contained in the Ar ² in the formula (1) can be measured, for example, using ¹ H-NMR, or can be calculated based on the addition ratio of the raw materials.

[式(2)中，Ar³ 表示具有供電子性基之二價芳香族基，Ar⁴ 及Ar⁵ 相互獨立地表示亦可具有取代基之二價芳香族基，其中，於Ar³ 與式(1)中之Ar¹ 相同且q為0時Ar⁴ 與式(1)中之Ar² 不同，W相互獨立地表示-O-、二苯基亞甲基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R²¹ )-、-Si(R²² )₂ -或碳數1～12之二價烴基，該烴基中所含之氫原子亦可相互獨立地由鹵素原子取代，亦可替換2個氫原子而形成環，R²¹ 及R²² 相互獨立地表示氫原子或亦可經鹵素原子取代之碳數1～12之一價烴基，q表示0～4之整數] 若聚醯胺系樹脂進而具有式(2)所示之結構單元，則有光學膜之表面硬度、耐水性、光學特性、彈性模數及降伏點應變等提高之情形。In one embodiment of the present invention, the polyamide resin may further have a structural unit represented by formula (2). [化13]

[In formula (2), Ar ³ represents a divalent aromatic group having an electron-donating group, and Ar ⁴ and Ar ⁵ independently represent a divalent aromatic group that may also have a substituent. Among them, Ar ³ and the formula Ar ¹ in (1) is the same and when q is 0, Ar ^{4 is} different from Ar ² in formula (1), and W independently represents -O-, diphenylmethylene, -SO ₂ -, -S- , -CO-, -PO-, -PO ₂ -, -N(R ²¹ )-, -Si(R ²² ) ₂ -or a divalent hydrocarbon group with 1 to 12 carbons, and the hydrogen atoms contained in the hydrocarbon group are also It can be substituted by a halogen atom independently of each other, or two hydrogen atoms can be substituted to form a ring. R ²¹ and R ²² independently represent a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms that can be substituted by a halogen atom, q Represents an integer of 0-4] If the polyamide-based resin further has the structural unit represented by formula (2), the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film may increase .

Ar ³ in the formula (2) represents a divalent aromatic group having an electron donating group. As a divalent aromatic group, it means a divalent monocyclic aromatic group, a divalent condensed polycyclic aromatic group, or a divalent condensed ring aromatic group. Examples of the divalent aromatic group include Ar ¹ in formula (1). Those exemplified by aromatic groups. Among them, from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, a divalent monocyclic aromatic group or a divalent aggregate ring aromatic group is preferred. , More preferably a group represented by formula (3), and still more preferably a phenylene group.

The divalent aromatic group in Ar ³ of formula (2) has an electron donating group. The electron-donating group is not particularly limited, and examples include: the substituent A of the divalent aromatic group in Ar ¹ in formula (1), that is, it is selected from the group consisting of 1 to carbon atoms that may have substituents. 12 alkyl groups, alkoxy groups with 1 to 12 carbons which may have substituents, aryl groups with 6 to 12 carbons which may have substituents, and aryloxy groups with 6 to 12 carbons which may have substituents At least one substituent in the group consisting of the group, and the preferred electron-donating group is the same as the preferred substituent A mentioned above. Ar ³ and Ar of formula (1) in the ¹ may be identical or different, preferably the same.

In a preferred embodiment of the present invention, the ratio of the group represented by formula (3) contained in Ar ³ in formula (2) to the molar amount of the structural unit represented by formula (2) is preferably It is 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the base shown in the formula (3) is in the above range, the optical film is likely to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. The ratio of the groups represented by the formula (3) can be measured using ¹ H-NMR, for example, or can be calculated based on the addition ratio of the raw materials.

In a preferred embodiment of the present invention, Ar ¹ in formula (1) is a structural unit of the group represented by formula (3) and Ar ² in formula (2) is a structure of the group represented by formula (3) The total ratio of the units is preferably 10 mol% or more with respect to the total molar amount of the structural unit represented by formula (1), the structural unit represented by formula (2), and the structural unit represented by formula (5), It is more preferably 30 mol% or more, still more preferably 50 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, and still more preferably 90 mol% or less.

Ar ⁴ and Ar ⁵ in the formula (2) independently represent a divalent aromatic group which may have a substituent. As a divalent aromatic group, it means a divalent monocyclic aromatic group, a divalent condensed polycyclic aromatic group, or a divalent condensed ring aromatic group. Examples of the divalent aromatic group include Ar ¹ in formula (1). Those exemplified by aromatic groups. Among them, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and yield point strain of the optical film, a divalent monocyclic aromatic group is preferred, and k is 1 more preferred. In this case, the group represented by formula (3) is more preferably phenylene. The divalent aromatic groups in Ar ⁴ and Ar ⁵ in formula (2) may have substituents (they may be referred to as substituent D). As the substituent D, the same as the substituent C of the divalent aromatic group in Ar ² in the formula (1), and the preferable substituent D is also the same as the preferable substituent C.

W in formula (2) independently represents -O-, diphenylmethylene, -SO ₂ -, -S-, -CO-, -PO-, -PO ₂ -, -N(R ²¹ ) -, -Si(R ²² ) ₂ -or a divalent hydrocarbon group with 1 to 12 carbons, the hydrogen atoms contained in the hydrocarbon group may be independently substituted by halogen atoms, or two hydrogen atoms may be replaced to form a ring, R ²¹ and R ²² independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbons which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbons in R ²¹ and R ²² include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-butyl, Pentyl, 2-methylbutyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, tertiary octyl, n-nonyl and n-decyl, etc. Etc. can also be substituted by halogen atoms. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.

Examples of the divalent hydrocarbon group having 1 to 12 carbons in W in formula (2) include a divalent group obtained by removing one hydrogen atom from the monovalent hydrocarbon group having 1 to 12 carbons in R ²¹ and R ²² These can also be substituted by halogen atoms. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned. In addition, among the hydrogen atoms contained in the divalent hydrocarbon group having 1 to 12 carbon atoms, two hydrogen atoms may be replaced to form a ring, that is, the two hydrogen atoms may be replaced with a bonding bond and the two bonding A bond is connected to form a ring, and examples of the ring include a cycloalkane ring having 3 to 12 carbon atoms. Among these W, from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, a divalent hydrocarbon group having 1 to 12 carbons and the Hydrocarbon groups such as those in which at least a part of the hydrogen atoms are substituted by halogen atoms, more preferably -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) _2- Or -C(CF ₃ ) ₂ -, more preferably -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, particularly preferably -C(CF ₃ ) ₂ -.

In formula (2), q is an integer of 0-4, and is advantageous in terms of surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, preferably 0- The integer of 3 is more preferably an integer of 0-2, more preferably 0 or 1, and particularly preferably 1. Furthermore, when Ar ³ is the same as Ar ¹ in formula (1) and q is 0, Ar ^{4 is} different from Ar ² in formula (1).

[式(32)中，R²⁶ ～R³² 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，R²⁶ ～R³² 中所含之氫原子亦可相互獨立地由鹵素原子取代，W^a 相互獨立地表示-O-、-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -、二苯基亞甲基、-SO₂ -、-S-、-CO-、-PO-、-PO₂ -、-N(R²¹ )-、-Si(R²² )₂ -，R²¹ 及R²² 相互獨立地表示氫原子或亦可經鹵素原子取代之碳數1～12之一價烴基] 即，式(2)中之複數個-Ar⁴ -W-Ar⁵ -中，至少一部分-Ar⁴ -W-Ar⁵ -為式(32)所示之基。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數、降伏點應變及耐彎曲性。再者，式(2)所示之結構單元亦可含有1種或複數種式(32)所示之基作為-Ar⁴ -W-Ar⁵ -。In a preferred embodiment of the present invention, the structural unit represented by formula (2) contains the group represented by formula (32) as Ar ⁴ -W-Ar ⁵ when q is 1. [化14]

[In formula (32), R ²⁶ to R ³² independently represent 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, R ²⁶ to The hydrogen atoms contained in R ³² may be independently substituted by halogen atoms, and W ^a independently represents -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-,- C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, diphenylmethylene, -SO ₂ -, -S-, -CO-, -PO-, -PO ₂ -, -N(R ²¹ )-, -Si(R ²² ) ₂ -, R ²¹ and R ²² independently represent a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms that can be substituted by a halogen atom] That is, in the formula (2) Among the plurality of -Ar ⁴ -W-Ar ⁵ -, at least a part of -Ar ⁴ -W-Ar ⁵ -is a group represented by formula (32). In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. Furthermore, the structural unit represented by formula (2) may also contain one or more types of groups represented by formula (32) as -Ar ⁴ -W-Ar ⁵ -.

R ²⁶ to R ³² independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. Examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons include the above-mentioned R ⁹ to R ¹⁶ of formula (5) with 1 carbon atoms. -6 alkyl groups, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons are exemplified. R ²⁶ to R ³² each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, where R ²⁶ to R ³² are contained The hydrogen atoms may also be substituted by halogen atoms independently of each other. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. W ^a each independently represent _{-O -, - CH 2 -,} - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, - C (CF 3) 2 -, two Phenylmethylene, -SO ₂ -, -S-, -CO-, -PO-, -PO ₂ -, -N(R ²¹ )-, -Si(R ²² ) ₂ -, R ²¹ and R ²² Independently represent hydrogen atoms or monovalent hydrocarbon groups with 1-12 carbons that can be substituted by halogen atoms, which can easily improve the surface hardness, water resistance, optical properties, elastic modulus, yield point strain and bending resistance of the optical film In terms of viewpoints, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -are preferred, and more preferred is -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably -C(CF ₃ ) ₂ -.

即，式(2)所示之結構單元於q為1之情形時含有式(33)所示之基作為-Ar⁴ -W-Ar⁵ -。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數、降伏點應變及耐彎曲性。再者，式(2)所示之結構單元亦可含有1種或複數種式(33)所示之基作為-Ar⁴ -W-Ar⁵ -。In a preferred embodiment of the present invention, equation (32) is represented by equation (33). [化15]

That is, the structural unit represented by formula (2) contains the group represented by formula (33) as -Ar ⁴ -W-Ar ⁵ -when q is 1. In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. Furthermore, the structural unit represented by formula (2) may also contain one or more kinds of groups represented by formula (33) as -Ar ⁴ -W-Ar ⁵ -.

In one embodiment of the present invention, the ratio of the formula (32) contained in the -Ar ⁴ -W-Ar ⁵ -in the formula (2), especially the base represented by the formula (33), is relative to that of the formula (2) The molar amount of the structural unit shown in) is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the base shown in formula (32), especially formula (33) is in the above range, the optical film is likely to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance. And by containing the fluorine element skeleton, the solubility of the resin in the solvent can be improved, the viscosity of the resin varnish can be kept low, and the optical film can be easily processed. The ratio of the groups represented by the formula (32) can be measured using ¹ H-NMR, for example, or can be calculated based on the addition ratio of the raw materials.

In the polyamide resin of the present invention, the ratio of the structural unit represented by formula (2) to 1 mol of the structural unit represented by formula (1) is preferably 0.01 mol or more, more preferably 0.05 mol Ear or more, more preferably 0.1 mol or more, and preferably 1 mol or less, more preferably 0.5 mol or less, and still more preferably 0.3 mol or less. If the ratio of the structural unit represented by the formula (2) is in the above range, the optical film may improve the excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance.

[式(5)中，X表示二價有機基，Y表示四價有機基] 若聚醯胺系樹脂進而具有式(5)所示之結構單元，則包含聚醯胺系樹脂而成之光學膜更易於顯現優異之表面硬度、耐水性、光學特性、彈性模數、降伏點應變及耐彎曲性。In one embodiment of the present invention, the polyamide resin may further have a structural unit represented by formula (5). [化16]

[In formula (5), X represents a divalent organic group, Y represents a tetravalent organic group] If the polyamide resin further has the structural unit represented by the formula (5), it contains the polyamide resin. The film is easier to show excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain and bending resistance.

X in the formula (5) independently represents a divalent organic group, preferably represents a divalent organic group having 4 to 40 carbons, and more preferably represents a divalent organic group having 4 to 40 carbons having a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. The above-mentioned organic group may also be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group for the hydrogen atom in the organic group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. The polyamide resin of one embodiment of the present invention may contain a plurality of types of X, and the plurality of 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 groups shown in the formulas (10) to (18) in which the hydrogen atoms in the groups represented by the formulas (10) to (18) are substituted by methyl, fluoro, chloro or trifluoromethyl; and those with 6 or less carbon atoms Chain hydrocarbon group.

[化17]

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 with 1 to 12 carbons which may be substituted with a halogen atom. Examples of monovalent hydrocarbon groups having 1 to 12 carbons that may be substituted by halogen atoms include the above-mentioned R ²¹ and R ²² in W in the formula (2), which may be substituted with halogen atoms and 1 to 12 carbon atoms. Those exemplified by monovalent hydrocarbon groups. For 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 position of V ¹ and V ² to each ring and the bonding position of V ² and V ³ to each ring are respectively relative to each ring, preferably meta or para, more preferably para.

Regarding the structural unit represented by formula (5), from the viewpoint of being advantageous in terms of surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, X is preferably The same group as Ar ² in formula (1) and/or the same group as -Ar ⁴ -(W-Ar ⁵ ) _q -in formula (2).

The ratio of the same group as Ar ² contained in X in formula (5) and/or the same group as -Ar ⁴ -(W-Ar ⁵ ) _q -in formula (2) relative to formula (5) The molar amount of the structural unit shown is preferably 50 mol% or more, more preferably 60 mol% or more, further preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the same group as Ar ² and/or the same group as -Ar ⁴ -(W-Ar ⁵ ) _q -in formula (2) contained as X is in the above range, the optical film is likely to exhibit excellent Surface hardness, water resistance, optical properties, elastic modulus, and bending resistance. The ratio of the same group as Ar ² and/or the same group as -Ar ⁴ -(W-Ar ⁵ ) _q -in the formula (2) can be measured, for example, by ¹ H-NMR, or can also be determined according to the addition of raw materials Calculate by comparison.

In the formula (5), Y independently represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbons, and more preferably a tetravalent organic group having 4 to 40 carbons having a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. The above-mentioned organic group may also be an organic group in which the hydrogen atom in the organic group is replaced by a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. The polyamide resin of an embodiment of the present invention may contain a plurality of Y, and the plurality of Y may be the same or different from each other. As Y, the following 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 formula (20) ~ formula (29) is substituted by a methyl group, a fluoro group, a chloro group or a trifluoromethyl group ; And tetravalent chain hydrocarbon group with carbon number 6 or less.

[化18]

In formulas (20) to (29), * represents a bonding bond, W ¹ represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom may be substituted by a fluorine atom, and a specific example includes a phenylene group.

Among the bases represented by formulas (20) to (29), in terms of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and bending resistance of the optical film, the formula (26), The group represented by formula (28) or formula (29) is more preferably the group represented by formula (26). In addition, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, and bending resistance of the optical film, W ¹ is preferably a single bond, -O-, -CH ₂ -,-independently of each other. CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably a single bond, -O-, -CH ₂ -, -CH (CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -.

[式(4)中，R² ～R⁷ 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，R² ～R⁷ 中所含之氫原子亦可相互獨立地由鹵素原子取代，V表示單鍵、-O-、-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -、-SO₂ -、-S-、-CO-或-N(R⁸ )-，R⁸ 表示氫原子或亦可經鹵素原子取代之碳數1～12之一價烴基，*表示鍵結鍵] 即，式(5)中之複數個Y中，至少一部分Y為式(4)所示之基。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數及耐彎曲性。再者，式(5)所示之結構單元亦可含有1種或複數種式(4)所示之基作為Y。In a preferred embodiment of the present invention, the structural unit represented by formula (5) contains the group represented by formula (4) as Y. [化19]

[In the formula (4), R ² to R ⁷ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons, R ² to The hydrogen atoms contained in R ⁷ can also be independently replaced by halogen atoms. V represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁸ )-, R ⁸ represents a hydrogen atom or can be substituted by a halogen atom A monovalent hydrocarbon group with 1 to 12 carbon atoms, * represents a bonding bond] That is, among the plurality of Y in formula (5), at least a part of Y is a group represented by formula (4). In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, and bending resistance. Furthermore, the structural unit represented by formula (5) may contain one or more types of groups represented by formula (4) as Y.

In formula (4), R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or carbon The number of aryl groups from 6 to 12. Examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons include the above-mentioned R ⁹ to R ¹⁶ of formula (5) with 1 carbon atoms. -6 alkyl groups, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons are exemplified. R ² to R ⁷ independently of each other preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbons, and more preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbons. Here, R ² to R ⁷ include The hydrogen atoms may also be substituted by halogen atoms independently of each other. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. V represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁸ )-, R ⁸ represents a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbons which may be substituted with a halogen atom. Examples of monovalent hydrocarbon groups having 1 to 12 carbons that may be substituted by halogen atoms include the above-mentioned R ²¹ and R ²² in W in the formula (2), which may be substituted with halogen atoms and 1 to 12 carbon atoms. Those exemplified by monovalent hydrocarbon groups. Among them, from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, and bending resistance of the optical film, V is preferably a single bond, -O-, -CH ₂ -, -CH( CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably It is a single bond or -C(CF ₃ ) ₂ -.

即，式(5)所示之結構單元含有式(7a)所示之結構單元及/或式(7b)所示之結構單元作為Y。若為此種態樣，則光學膜易於顯現優異之表面硬度、耐水性、光學特性、彈性模數及耐彎曲性。又，藉由含有氟元素之骨架，可提高樹脂向溶劑中之溶解性，將樹脂清漆之黏度抑制為較低，且可容易地進行光學膜之加工。式(5)中之複數個Y亦可含有1種或複數種式(7a)或式(7b)所示之結構單元。In a preferred embodiment of the present invention, formula (4) is represented by formula (7a) or formula (7b). [化20]

That is, the structural unit represented by formula (5) contains the structural unit represented by formula (7a) and/or the structural unit represented by formula (7b) as Y. In this aspect, the optical film tends to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, and bending resistance. In addition, the fluorine-containing skeleton can improve the solubility of the resin in the solvent, suppress the viscosity of the resin varnish to a low level, and can easily process the optical film. The plurality of Y in formula (5) may also contain one or more structural units represented by formula (7a) or formula (7b).

In a preferred embodiment of the present invention, the ratio of formula (4) contained in Y in formula (5), especially formula (7a) and/or formula (7b), is relative to formula (5) The molar amount of the structural unit shown in) is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of formula (4) contained as Y in formula (5), especially formula (7a) and/or formula (7b), is in the above range, the optical film is likely to exhibit excellent surface hardness, Water resistance, optical properties, elastic modulus, and bending resistance. In addition, the fluorine-containing skeleton can improve the solubility of the resin in the solvent, suppress the viscosity of the resin varnish to a low level, and can easily process the optical film. The ratio of the group represented by the formula (4) contained in Y in the formula (1) can be measured using ¹ H-NMR, for example, or can be calculated based on the addition ratio of the raw materials.

In the polyamide resin of the present invention, the ratio of the structural unit represented by the formula (5) is 1 mol relative to the total amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2), Preferably it is 0.01 mol or more, more preferably 0.05 mol or more, still more preferably 0.1 mol or more, still more preferably 0.2 mol or more, particularly preferably 0.5 mol or more, and preferably 5 mol or less , More preferably 3 mol or less, and still more preferably 1 mol or less. If the ratio of the structural unit shown in formula (5) is in the above range, it is easy to improve the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film. Furthermore, when the polyamide-based resin does not contain the structural unit represented by the formula (2), the molar amount of the structural unit represented by the formula (1) is used as a reference.

[式(8)中，K及L相互獨立地表示二價有機基]In one embodiment of the present invention, the polyamide resin of the present invention may also contain a structural unit represented by formula (8). [化21]

[In formula (8), K and L independently represent a divalent organic group]

In formula (8), L is a divalent organic group independently of each other, and can be selected from the same divalent organic groups as X in formula (5).

In formula (8), K is a divalent organic group independently of each other, preferably two of 4-40 carbons which may be substituted by a hydrocarbon group with 1 to 8 carbons or a hydrocarbon group with 1 to 8 carbons substituted by fluorine The valent organic group more preferably represents a divalent organic group with 4 to 40 carbons that can be substituted by a hydrocarbon group with 1 to 8 carbons or a hydrocarbon group with 1 to 8 carbons substituted by fluorine and has a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. As the organic group of K, the formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( 28) and the two non-adjacent bonding bonds of the group represented by the formula (29) are replaced with hydrogen atoms and a divalent chain hydrocarbon group with 6 or less carbon atoms. As the heterocyclic structure of Z, there can be exemplified From the viewpoint of easily suppressing the yellowness of the optical film (hereinafter referred to as YI value) as the base of the thiophene ring skeleton, it is preferable to exemplify the group represented by formula (20) to formula (28) and having a thiophene ring The base of the skeleton.

[式(20')～式(29')中，W¹ 及*如式(20)～式(29)中所定義] 再者，式(20)～式(29)及式(20')～式(29')中之環上之氫原子亦可由碳數1～8之烴基或經氟取代之碳數1～8之烴基、碳數1～6之烷氧基或經氟取代之碳數1～6之烷氧基取代。As the organic group of K, it is more preferably formula (20'), formula (21'), formula (22'), formula (23'), formula (24'), formula (25'), formula (26') , Formula (27'), Formula (28') and Formula (29') as shown in the divalent organic group. [化22]

[In formulas (20') to (29'), W ¹ and * are as defined in formulas (20) to (29)] Furthermore, formulas (20) to (29) and (20') ～The hydrogen atom on the ring in formula (29') can also be a hydrocarbon group with 1 to 8 carbons or a hydrocarbon group with 1 to 8 carbons substituted by fluorine, an alkoxy group with 1 to 6 carbons or a carbon substituted with fluorine Alkoxy substituted with number 1 to 6.

[式(d1)中，R^c 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，R^d 表示R^c 或-C(=O)-*，*表示鍵結鍵]When the polyamide-based resin has a structural unit represented by any one of the above-mentioned formulas (20') to (29') in the formula (8), K in the formula (8) In the case of the structural unit represented by the formula (9a) described later, from the viewpoint of easily improving the film-forming properties of the varnish, the polyamide resin preferably has the following formula (d1) in addition to the structural unit Shown are structural units derived from carboxylic acids. [化23]

[In formula (d1), R ^c independently represents a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons, and R ^d represents R ^c or -C(=O)-*, * means bonding key]

In R ^c , examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons include the alkane having 1 to 6 carbons in formula (5). Exemplified by the group, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. As the structural unit (d1), specifically, a structural unit in which R ^c and R ^d are both hydrogen atoms (a structural unit derived from a dicarboxylic acid compound), R ^c is a hydrogen atom, and R ^d represents -C (=O)-*The structural unit (the structural unit derived from the tricarboxylic acid compound), etc.

[式(9a)中，R^a 及R^b 相互獨立地表示鹵素原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R^a 及R^b 中所含之氫原子亦可相互獨立地由鹵素原子取代，A、m及*分別與式(9)中之A、m及*相同，t為0～4之整數，u為0～4之整數] 更佳含有式(9)所示之基作為K。 [化25]

[式(9)中，R¹⁷ ～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，R¹⁷ ～R²⁴ 中所含之氫原子亦可相互獨立地由鹵素原子取代，A表示單鍵、-O-、-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -、-SO₂ -、-S-、-CO-或-N(R²⁵ )-，R²⁵ 表示氫原子或亦可經鹵素原子取代之碳數1～12之一價烴基，m為0～4之整數，*表示鍵結鍵] 即，式(8)中之複數個K中，至少一部分K較佳為式(9a)所示之基，更佳為式(9)所示之基。The polyamide resin of the present invention may contain a plurality of types of K as K in formula (8), and the plurality of types of K may be the same or different from each other. Among them, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, it is preferable that the structural unit represented by formula (8) preferably contains formula ( 9a) shows the base as K, [化24]

[In the formula (. 9A), R ^a and R ^b each independently represent a halogen atom, an alkyl group having a carbon number of 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms of the aryl group having 6 to 12, R ^a, and The hydrogen atoms contained in R ^b can also be independently substituted by halogen atoms. A, m and * are the same as A, m and * in formula (9), t is an integer from 0 to 4, and u is from 0 to Integer of 4] It is more preferable to contain the group represented by formula (9) as K. [化25]

[In formula (9), R ¹⁷ to R ²⁴ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons, R ¹⁷ to The hydrogen atoms contained in R ²⁴ can also be independently replaced by halogen atoms. A represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ²⁵ )-, R ²⁵ represents a hydrogen atom or can be substituted by a halogen atom A monovalent hydrocarbon group with 1 to 12 carbon atoms, m is an integer from 0 to 4, and * represents a bonding bond] That is, among the plurality of K in formula (8), at least a part of K is preferably represented by formula (9a) The group is more preferably the group represented by formula (9).

In the formula (9a), the bonding bond of each benzene ring can be bonded to any one of the ortho, meta or para position based on -A-, and preferably can be bonded to the meta or para position. R ^a and R ^b independently represent a halogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. In the formula (9a), t and u are preferably 0. When t and/or u are 1 or more, R ^a and R ^b independently of each other preferably represent an alkyl group having 1 to 6 carbon atoms, more preferably An alkyl group having 1 to 3 carbon atoms. In R ^a and R ^b in the formula (9a), as a halogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, and an aryl group with 6 to 12 carbons, the formula (5) Examples of halogen atoms, C1-C6 alkyl groups, C1-C6 alkoxy groups, or C6-C12 aryl groups.

In the formula (9a), t and u are independently an integer of 0-4, preferably an integer of 0-2, and more preferably 0 or 1.

In formula (9) and formula (9a), A independently represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ²⁵ )-, it is easy to improve the surface hardness, water resistance, optical properties, elastic modulus of the optical film In terms of number, yield point strain, and bending resistance, it is preferably -O- or -S-, and more preferably -O-. The polyamide resin of one embodiment of the present invention may contain a plurality of A, and the plurality of A may be the same or different.

In formula (9), R ¹⁷ to R ²⁴ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. The alkyl groups having 1 to 6 carbons, the alkoxy groups having 1 to 6 carbons, and the aryl groups having 6 to 12 carbons respectively include the above-mentioned R ⁹ to R ¹⁶ in the formula (5) with carbon numbers 1 to 6 The alkyl group, the alkoxy group having 1 to 6 carbons, and the aryl group having 6 to 12 carbons are exemplified. From the viewpoints of the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, R ¹⁷ to R ²⁴ independently preferably represent a hydrogen atom or an alkane with 1 to 6 carbon atoms. The group more preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably represents a hydrogen atom. Here, the hydrogen atoms contained in R ¹⁷ to R ²⁴ may be independently substituted with halogen atoms. R ²⁵ represents a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbons which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group with 1 to 12 carbons which may be substituted with a halogen atom include the above formula (2) Among W, R ²¹ and R ²² are exemplified by a monovalent hydrocarbon group with 1 to 12 carbon atoms that may be substituted by a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.

In formula (9) and formula (9a), m is an integer from 0 to 4, preferably an integer in the range of 1 to 4. If m is within this range, the surface hardness, water resistance, optical properties, The elastic modulus, yield point strain and bending resistance are good. In addition, in formula (9) and formula (9a), m is preferably an integer in the range of 1 to 3, more preferably 1 or 2, and more preferably 1, if m is within this range, the surface of the optical film Hardness, water resistance, optical properties, elastic modulus, yield point strain and bending resistance are good, and the availability of raw materials is relatively good. Furthermore, when m is 0, u in formula (9a) is preferably 0, and R ²¹ to R ²⁴ in formula (9) are preferably hydrogen atoms. In addition, the structural unit represented by the formula (8) may contain one or more of the groups represented by the formula (9) or the formula (9a) as K.

即，式(8)所示之結構單元含有式(9')所示之基作為K。In a preferred embodiment of the present invention, in terms of the ease of improving the surface hardness, water resistance, optical properties, elastic modulus, yield point strain and bending resistance of the optical film, the formula (9) is represented by the formula (9' ) Shown. [化26]

That is, the structural unit represented by formula (8) contains the group represented by formula (9') as K.

In one embodiment of the present invention, the ratio of formula (9a) or formula (9) contained in K in formula (8), especially the base shown in formula (9'), is relative to that of formula (8) The molar amount of the structural unit shown is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less. If the ratio of the structural unit represented by formula (8) is in the above range, it is advantageous in terms of surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film.

In one embodiment of the present invention, when the polyamide resin contains the structural unit represented by the formula (8), the formula (9a) or the formula (9) contained in the K in the formula (8), In particular, the ratio of the base represented by formula (9') to the total molar amount of the structural units represented by formula (1), formula (2), and formula (8) is preferably 5 mol% or more, more It is preferably 8 mol% or more, more preferably 10 mol% or more, particularly preferably 12 mol% or more, and preferably 90 mol% or less, more preferably 70 mol% or less, and still more preferably 50 mol% or less, more preferably 30 mol% or less. If the ratio of formula (9a) or formula (9), especially formula (9') of the base is above the above lower limit, the optical film is likely to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, and yield Point strain and bending resistance, and if it is less than the above upper limit, the tackification caused by the hydrogen bond between the amide bonds in formula (8) can be suppressed, the viscosity of the resin varnish can be reduced, and the optical film can be easily applied manufacture. The ratio of the groups represented by the formula (9a) or the formula (9) can be measured using ¹ H-NMR, for example, or can be calculated based on the addition ratio of the raw materials.

In one embodiment of the present invention, when the polyamide resin contains the structural unit represented by the formula (8), the ratio of the structural unit represented by the formula (8) relative to the formula (1) and formula (2) ), the total amount of the structural units shown in formula (5) and formula (8) is 1 mol, preferably 0.01 mol or more, more preferably 0.5 mol or more, still more preferably 0.1 mol or more, and more It is preferably 1 mol or less, more preferably 0.5 mol or less, and still more preferably 0.3 mol or less. If the ratio of the structural unit represented by formula (8) is more than the above lower limit, the optical film is likely to exhibit excellent surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance, and can suppress The viscosity increase caused by the hydrogen bonds between the amide bonds in the formula (8) reduces the viscosity of the resin varnish and facilitates the manufacture of optical films. The ratio of the structural unit represented by the formula (8) 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), formula (2), formula (5) and formula (8), the polyamide resin in the present invention may contain structural units represented by formula (30) and/or The structural unit shown in formula (31). [化27]

In formula (30), Y ¹ is a tetravalent organic group, preferably an organic group in which the hydrogen atom in the organic group can also be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples of Y ^{1 include} : 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 formula (20) ~ formula (29) is substituted by a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; And tetravalent chain hydrocarbon group with carbon number 6 or less. The polyamide resin of one embodiment of the present invention may contain a plurality of Y ¹ , and the plurality of Y ¹ may be the same or different from each other.

In formula (31), Y ² is a trivalent organic group, preferably an organic group in which the hydrogen atom in the organic group can be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ² , the above-mentioned formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( 28) and any one of the bonding bonds of the group represented by formula (29) is replaced with a hydrogen atom; and a trivalent chain hydrocarbon group with 6 or less carbon atoms. The polyamide resin of one embodiment of the present invention may contain a plurality of types of Y ² , and the plurality of types of Y ² may be the same or different from each other.

In formula (30) and formula (31), X ¹ and X ² are independently a divalent organic group, preferably an organic group in which the hydrogen atom in the organic group may be substituted by 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 formula (18); the hydrogen atom in the group represented by formula (10) to formula (18) is substituted by methyl, fluoro, chloro or trifluoromethyl; and Chain hydrocarbon group with carbon number 6 or less.

In one embodiment of the present invention, the polyamide resin includes a structural unit represented by formula (1) and optionally selected from structural units represented by formula (2), structural units represented by formula (5), and At least one of the structural units represented by formula (8). In addition, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, in the above-mentioned polyamide-based resin, formula (1) and formula (2) The total molar amount of the structural unit shown in formula (8) is based on the total molar of all structural units shown in formula (1), formula (2), formula (8), formula (30) and formula (31) The amount is preferably 80 mol% or more and more preferably 100 mol% or less. 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.

The weight average molecular weight of the polyamide resin in terms of polystyrene is preferably 150,000 or more, more preferably 200,000 or more, and preferably 1,000,000 or less, more preferably 800,000 or less, further preferably 700,000 or less, particularly preferably 500,000 the following. If the weight average molecular weight of the polyamide-based resin is more than the above lower limit, the optical film tends to increase surface hardness, water resistance, optical properties, elastic modulus, yield point strain and bending resistance, and if it is less than the above upper limit, then The viscosity of the resin varnish can be suppressed to be low, and it is easy to form the optical film, so the processability becomes good. The weight average molecular weight can be determined by, for example, GPC (gel permeation chromatograph) measurement and calculated in terms of standard polystyrene. For example, it can be determined by the method described in the examples.

In one embodiment of the present invention, the polyamide resin contains halogen atoms. Since the polyamide-based resin contains halogen atoms, the YI value of the optical film may be reduced, and there is a tendency to have both high flexibility and bending resistance. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. From the viewpoints of the decrease in the YI value of the optical film, that is, the increase in transparency, the decrease in water absorption, and the bending resistance, it is preferably Fluorine atom. Specific examples of the fluorine-containing substituent in the polyamide-based resin include a fluoro group and a trifluoromethyl group.

Regarding the content of halogen atoms in the polyamide resin, from the viewpoint of the decrease in YI value, that is, the increase in transparency, the decrease in water absorption, and the bending resistance of the optical film, the quality of the polyamide resin is The standard is preferably 1 to 40% by mass, more preferably 3 to 35% by mass, and still more preferably 5 to 32% by mass.

In an embodiment of the present invention, the imidization rate of the polyamide resin is preferably 95-100%, more preferably 97-100%, and still more preferably 98-100%. From the standpoint of the stability of the resin varnish and the mechanical properties of the resulting optical film, the imidization rate is preferably at least the above lower limit. In addition, the imidization rate can be obtained by IR (infrared radiation, infrared spectroscopy) method, NMR method, etc.

In one embodiment of the present invention, relative to 100 parts by mass of the optical film, the polyamide resin is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 60 parts by mass or more, and more preferably It is 100 parts by mass or less.

In one embodiment of the present invention, the polyamide resin can be obtained by reacting (condensing) a diamine compound, a dicarboxylic acid compound, and optionally a tetracarboxylic acid compound and a tricarboxylic acid compound. The structural units represented by formula (1), formula (2) and formula (8) are usually derived from diamine compounds and dicarboxylic acid compounds. The structural units represented by formula (5) and formula (30) are usually derived from diamine compounds and tetracarboxylic acid compounds. The structural unit represented by formula (31) is usually derived from a diamine compound and a tricarboxylic acid compound.

Examples of tetracarboxylic acid compounds used in the synthesis of polyamide resins include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride; and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. . 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 a tetracarboxylic acid compound close body 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. Examples of non-condensed polycyclic aromatic tetracarboxylic dianhydrides include: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid Dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sometimes recorded as BPDA), 2 ,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxybenzene Base) propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4 '-(Hexafluoroisopropylidene) diphthalic dianhydride (in the case of 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'-(m-phenylenedioxy) diphthalic dianhydride. In addition, examples of monocyclic aromatic tetracarboxylic dianhydrides include 1,2,4,5-benzenetetracarboxylic dianhydride, and examples of condensed polycyclic aromatic tetracarboxylic dianhydrides include 2,3,6,7-Naphthalenetetracarboxylic dianhydride. Among these, preferably 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3 '-Benzophenone tetracarboxylic dianhydride, 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-dicarboxybenzene) Base) propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (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 and 4,4'-(m-phenylenedioxy)di-ortho Phthalic dianhydride, more preferably 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,2', 3,3'-Biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), bis(3,4-dicarboxyphenyl)methane Anhydride and 4,4'-(p-phenylenedioxy) diphthalic dianhydride. These can be used individually or in combination of 2 or more types.

As the aliphatic tetracarboxylic dianhydride, cyclic or acyclic aliphatic tetracarboxylic dianhydride can be mentioned. The so-called cyclic aliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include: 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1 , 2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride and other cycloalkane tetracarboxylic dianhydrides; bicyclo[2.2.2]oct-7 -En-2,3,5,6-tetracarboxylic dianhydride; dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride; and positional isomers of these. These can be used individually or in combination of 2 or more types. Specific examples of acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentane tetracarboxylic dianhydride, etc. These can be used individually or in combination of 2 or more types. In addition, it is also possible to use a combination of cyclic aliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride.

Among the above-mentioned tetracarboxylic dianhydrides, from the viewpoint of easy improvement of the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film, 4,4'-oxydicarboxylate Phthalic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 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 , 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride and mixtures of these, more preferably 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) And 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA), and mixtures of these.

As the dicarboxylic acid compound used in the synthesis of the polyamide-based resin, aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and these related chlorinated compounds, acid anhydrides, etc. may be mentioned, and two or more kinds may be used in combination. Specific examples include: terephthalic acid; isophthalic acid; 2-methylterephthalic acid; 2,5-dimethylterephthalic acid; 2-methoxyterephthalic acid; 2, 5-Dimethoxyterephthalic acid; naphthalenedicarboxylic acid; 4,4'-biphthalic acid; 3,3'-biphthalic acid; dicarboxylic acid compound of chain hydrocarbon with carbon number 8 or less; and Compounds in which two benzoic acids are linked by a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene; and these compounds Chlorine compounds. Among these dicarboxylic acid compounds, the 4,4'-oxy group is preferred from the viewpoint of easily improving the surface hardness, water resistance, optical properties, elastic modulus, yield point strain, and bending resistance of the optical film Bisbenzoic acid, terephthalic acid, 2-methylterephthalic acid, 2,5-dimethylterephthalic acid, 2-methoxyterephthalic acid, 2,5-dimethoxyterephthalic acid Dicarboxylic acid and these chlorines, more preferably 2-methoxyterephthalate chloride (OMTPC), 2,5-dimethylterephthalate chloride (DMTPC) and 2,5-dimethyl Oxy-terephthalic acid chloride (2MOTPC).

Furthermore, the above-mentioned polyamide-based resin can also be used in a range that does not impair various physical properties of the optical film. In addition to the tetracarboxylic acid compound used in the synthesis of the above-mentioned polyamide-based resin, other tetracarboxylic acids and tricarboxylic acids Acid, and these acid anhydrides and derivatives reacted.

Examples of other tetracarboxylic acids include water adducts of acid anhydrides of the aforementioned tetracarboxylic acid compounds.

As a tricarboxylic acid compound, aromatic tricarboxylic acid, aliphatic tricarboxylic acid, and these close chlorinated compounds, acid anhydride, etc. are mentioned, You may use in combination of 2 or more types. Specific examples include: 1,3,5-benzenetricarboxylic acid and its chloride, anhydrides of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3- Anhydride; phthalic anhydride and benzoic acid are linked by single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene From the compound.

As the diamine compound used in the synthesis of the polyamide resin, for example, aliphatic diamine, aromatic diamine, and mixtures thereof can be cited. Furthermore, the term "aromatic diamine" in this embodiment means a diamine in which an amine group is directly bonded to an aromatic ring, and a part of its structure may also contain an aliphatic group or other substituents. This aromatic ring may be a monocyclic ring or a condensed ring, and a benzene ring, a naphthalene ring, an anthracene ring, a sulphur ring, etc. can be illustrated, but it is not limited to these. Among them, a benzene ring is preferred. In addition, the term "aliphatic diamine" means a diamine in which an amine group is directly bonded to an aliphatic group, and a part of its structure may contain an aromatic ring or other substituents.

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

Examples of aromatic diamines include 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'- Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4 '-Diaminodiphenyl benzene, 3,3'-Diaminodiphenyl benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminobenzene) Oxy) 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, 2,2' -Bis(trifluoromethyl)-4,4'-diaminobiphenyl (in the case of TFMB), 4,4'-(hexafluoropropylene) diphenylamine (in the case of 6FDAM) , 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)pyridium, 9,9-bis(4-amino-3-methylbenzene) Group) pyrene, 9,9-bis(4-amino-3-chlorophenyl) pyrene, 9,9-bis(4-amino-3-fluorophenyl) pyrene, etc., which have more than 2 aromatic rings Aromatic diamine. 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, 2,2'-bis (Trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, more preferably 4,4'-diaminobiphenyl Diphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 1,4-bis( 4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl] chrysene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-Dimethylbenzidine, 2,2'-Bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-(hexafluoropropylene) Diphenylamine (6FDAM), 4,4'-bis(4-aminophenoxy)biphenyl. These can be used individually or in combination of 2 or more types.

Among the above-mentioned diamine compounds, it is preferable to use a composition selected from aromatic diamines having a biphenyl structure from the viewpoint of easily improving the elastic modulus, optical properties, surface hardness, bending resistance, and water resistance of the optical film More than one species in the group. More preferably, use selected from 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis One of the group consisting of (4-aminophenoxy)biphenyl, 4,4'-(hexafluoropropylene)diphenylamine (6FDAM) and 4,4'-diaminodiphenyl ether Above, it is more preferable to use 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) and/or 4,4'-(hexafluoropropylene)diphenylamine (6FDAM).

In the production of polyamide resins, the amount of diamine compound and dicarboxylic acid compound, as well as any tetracarboxylic acid compound and tricarboxylic acid compound, can be adjusted according to the ratio of the structural units of the polyamide resin. Choose appropriately.

In the production of the polyamide resin, the reaction temperature is not particularly limited, and is, for example, 5 to 200°C, preferably 5 to 100°C, more preferably 5 to 50°C, and still more preferably 5 to 25°C. The reaction time is also not particularly limited, and is, for example, about 30 minutes to 10 hours. If necessary, the reaction can be carried out under an inert atmosphere or under reduced pressure. In a preferred aspect, the reaction is carried out while stirring under normal pressure and/or an inert gas atmosphere. Furthermore, the reaction is preferably carried out in a solvent inert to the reaction. 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, 1 -Methoxy-2-propanol, 2-butoxyethanol, propylene glycol monomethyl ether and other alcoholic solvents; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, γ -Valerolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone and other ketones 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; amine-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; dimethyl sulfide, dimethyl Sulfur-containing solvents such as sulfite and cyclobutyl; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations (mixed solvents) of these. Among these, from the viewpoint of solubility, an amide-based solvent can be preferably used.

In a preferred embodiment of the present invention, when the polyimide resin is manufactured, the manufacturing method is not particularly limited as long as the polyimide resin can be obtained, and it is easy to improve the optical film. From the viewpoints of water resistance and surface hardness, it is preferable to produce a polyamide by a method of reacting a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound, and a method of adding the dicarboxylic acid compound in batches. The amidoimide resin is more preferably produced by a method including the step (I) of reacting a diamine compound and a tetracarboxylic acid compound to produce an intermediate (A), And the step (II) of reacting the intermediate (A) with the dicarboxylic acid compound, and the dicarboxylic acid compound is added in batches in the step (II).

Although the reason is not clear by using a method of adding a dicarboxylic acid compound in batches, it is thought that a polyamide resin that is most suitable for improving water resistance and surface hardness can be obtained. Moreover, it is easy to adjust the weight average molecular weight of a polyamide imide resin to the said range.

Therefore, the polyamide resin (polyamide imide resin) contained in the optical film of the present invention and the polyamide resin (polyamide imide resin) of the present invention are preferably obtained by using A resin produced by a production method in which a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound are reacted and is a production method in which the dicarboxylic acid compound is added in batches. It is more preferably a resin produced by the following production method. The production method includes the step (I) of reacting the diamine compound and the tetracarboxylic acid compound to produce the intermediate (A), and the step (II) of reacting the intermediate (A) with the dicarboxylic acid compound, and In this step (II), the dicarboxylic acid compound is added in batches. A polyamide resin (polyamide resin) having at least the above-mentioned structural unit (1) and structural unit (5) and a weight average molecular weight of 200,000-1,000,000 is produced by a manufacturing method including a step of adding a dicarboxylic acid compound in batches. In the case of amine imide resin), it is easy to make the weight average molecular weight of the polyamide resin within the above-mentioned range.

In the case of producing a polyamide imide resin by the above-mentioned production method including step (I) and step (II), a step of reacting a diamine compound and a tetracarboxylic acid compound to produce an intermediate (A) The reaction temperature of (I) is not particularly limited. For example, it may be 5 to 200°C, preferably 5 to 100°C, more preferably 5 to 50°C, and still more preferably 5 to 25°C. The reaction time can be, for example, 1 minute to 72 hours, preferably 10 minutes to 24 hours. In addition, the reaction can be carried out while stirring in air or in an inert gas atmosphere (for example, nitrogen, argon, etc.), and can also be carried out under normal pressure, under pressure or under reduced pressure. In a preferred embodiment, it is carried out while stirring under normal pressure and/or an inert gas atmosphere.

In step (I), the diamine compound reacts with the tetracarboxylic acid compound to produce the intermediate (A), that is, polyamide acid. Therefore, the intermediate (A) has at least a structural unit derived from a diamine compound and a structural unit derived from a tetracarboxylic acid compound.

Next, in step (II), the intermediate (A) is reacted with the dicarboxylic acid compound. Here, it is preferable to add the dicarboxylic acid compound in batches. The dicarboxylic acid compound is added to the reaction solution obtained in step (I) in batches, and the intermediate (A) and the dicarboxylic acid compound are reacted. By adding the dicarboxylic acid compound in batches rather than at once, it is easy to increase the molecular weight of the polyimide resin. Furthermore, in this specification, the so-called batch addition refers to adding the dicarboxylic acid compound to be added in several times. More specifically, the dicarboxylic acid to be added is divided into specific amounts and added separately at specific intervals (specific times). . The specific interval (specific time) also includes a very short interval (or time), so batch addition also includes continuous addition (or continuous feeding).

In step (II), the number of batches when the dicarboxylic acid compound is added in batches can be appropriately selected according to the scale of the reaction or the types of raw materials, etc., preferably 2-20 times, more preferably 3-10 times, and more preferably For 3 to 6 times. If the number of batches is in the above range, it is easy to increase the molecular weight of the polyimide resin.

The dicarboxylic acid compound may be added in equal amounts in batches, or added in uneven amounts in batches. The time between each addition (hereinafter referred to as the addition interval) may all be the same or different. In addition, when two or more dicarboxylic acid compounds are added, the term "addition in batches" refers to adding the total amount of all dicarboxylic acid compounds in batches. There is no method for batching each dicarboxylic acid compound. Particularly limited, for example, each dicarboxylic acid compound may be added at once or in batches, or each dicarboxylic acid compound may be added in batches together, or a combination of these may be used.

In step (II), it is preferable that the weight average molecular weight of the polyimide resin reaches 10% or more, more preferably 15% relative to the weight average molecular weight of the obtained polyimide resin. At the above time point, the dicarboxylic acid compound is added preferably at 1-40 mol%, more preferably 2-25 mol% relative to the total molar amount of the dicarboxylic acid compound to be added.

The reaction temperature of step (II) is not particularly limited, and may be, for example, 5 to 200°C, preferably 5 to 100°C, more preferably 5 to 50°C, and still more preferably 5 to 25°C. In addition, the reaction can be carried out while stirring in air or in an inert gas atmosphere such as nitrogen or argon, and can also be carried out under normal pressure, under pressure, or under reduced pressure. In a preferred aspect, step (II) is performed while stirring under normal pressure and/or an inert gas atmosphere.

In step (II), the dicarboxylic acid compound is added in batches and then stirred for a specific period of time to make it react to obtain a polyamide imine precursor. Furthermore, the polyimide imine precursor can be precipitated by adding a large amount of water to the reaction solution containing the polyimide imine precursor, and filtered, Concentrate, dry, etc. and separate.

In step (II), the intermediate (A) is reacted with the dicarboxylic acid compound to obtain a polyimide imine precursor. Therefore, the polyimide imine precursor means at least the structural unit derived from the diamine compound, the structural unit derived from the tetracarboxylic acid, and the structural unit derived from the dicarboxylic acid compound before the imidization (before ring closure) The polyamide imide.

In the case of the production of polyimide resins, the method for producing polyimide resins may further include subjecting the polyimide imide precursor to imine Step (III) of transformation. By supplying the polyamide imide precursor obtained in step (II) to step (III), the structural unit part of the polyamide imide precursor has a polyamide acid structure. By imidization (ring closure), a polyamide resin having at least the structural unit represented by formula (1) and the structural unit represented by formula (5) can be obtained. Examples of the imidization catalyst include: aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, N -Alicyclic amines such as butylpyrrolidine, N-butylpiperidine, and N-propylhexahydroazepine (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, 2,4-lutidine, Aromatic amines such as 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, 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. Examples of the acid anhydride include commonly used acid anhydrides used in the imidization reaction, and specific examples thereof include aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride; aromatic acid anhydrides such as phthalic acid and the like.

Polyamide resins can also be isolated (separated and refined) by conventional methods, such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography and other separation methods or a combination of these separation methods. In a preferred aspect, a large amount of alcohol such as methanol can be added to the reaction liquid containing the resin to precipitate the resin and be isolated by concentration, filtration, drying, etc.

＜Additives＞ The optical film of the present invention may also contain additives. The additives can be appropriately selected according to the use of the optical film, and examples thereof include fillers such as silica particles, leveling agents, antioxidants, ultraviolet absorbers, bluing agents, plasticizers, and surfactants. These additives can be used alone or in combination of two or more. When the optical film contains an additive, the content of the additive relative to 100 parts by mass of the optical film is, for example, 0.001 to 60 parts by mass, preferably 0.1 to 40 parts by mass, and more preferably about 0.2 to 20 parts by mass.

＜Optical film＞ Since the optical film of the present invention contains the above-mentioned polyamide-based resin, the water resistance and surface hardness are improved, and it can have both excellent water resistance and excellent surface hardness. Therefore, even if the optical film of the present invention is applied to the front panel of a display device, the occurrence of dent defects, cracks, breakage, etc. on the surface can be suppressed, and defects such as swelling can be suppressed even when exposed to a high-humidity environment. Furthermore, the optical film of the present invention can also have excellent optical properties. Furthermore, in this specification, the so-called optical characteristics refer to, for example, the characteristics that can be optically evaluated, including total light transmittance, YI value, and haze. The so-called "improvement of optical characteristics", for example, means that the total light transmittance becomes higher, and the YI value When it becomes lower, the haze becomes lower.

The thickness of the optical film of the present invention is appropriately adjusted according to the application, and is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, It is more preferably 65 μm or less, and particularly preferably 55 μm or less. The thickness of the optical film can be measured with a film thickness meter or the like, for example, by the method described in the examples. Polyamide resins, especially optical films containing polyamide resins, may be difficult to thicken for higher strength. However, in one embodiment of the present invention, relatively thick optical films can be formed.

In one embodiment of the present invention, the total light transmittance is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, and usually 100% or less. If the total light transmittance is higher than the above lower limit, the transparency becomes good. For example, when it is used in the front panel of a display device, it can contribute to higher visibility. Furthermore, the total light transmittance can be the total light transmittance within the above-mentioned thickness range of the optical film. In addition, the total light transmittance can be measured using a haze meter in accordance with JIS (Japanese Industrial Standards) K 7105:1981, and can be measured, for example, by the method described in the examples.

In one embodiment of the present invention, the haze of the optical film of the present invention is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, still more preferably 0.5% or less, and particularly preferably 0.3% or less, and usually 0.01% or more. If the haze of the optical film is less than the above upper limit, the transparency becomes good. For example, when it is used in the front panel of a display device, it can contribute to higher visibility. In addition, the haze can be measured using a haze meter in accordance with JIS K 7136:2000, for example, and can be measured by the method described in the examples.

In one embodiment of the present invention, the YI value of the optical film of the present invention is preferably 8 or less, more preferably 5 or less, still more preferably 4 or less, still more preferably 3 or less, particularly preferably 2 or less, and It is usually -5 or more, preferably -2 or more. If the YI value of the optical film is less than the above upper limit, the transparency becomes good. For example, when it is used in the front panel of a display device, it can contribute to higher visibility. Furthermore, the YI value can be measured, for example, in accordance with JIS K 7373: 2006, using an ultraviolet-visible-near-infrared spectrophotometer to measure the transmittance of light from 300 to 800 nm, and obtain the tristimulus values (X, Y, Z) based on YI =100×(1.2769X-1.0592Z)/Y.

In one embodiment of the present invention, the pencil hardness of the optical film of the present invention is preferably 5B or higher, more preferably 3B or higher, more preferably B or higher, and particularly preferably H or higher. In addition, it can be measured in accordance with JIS K 5600-5-4: 1999, and can be measured, for example, by the method described in the examples.

In one embodiment of the present invention, the humidity linear expansion rate shown by CME (Coefficient of Moisture Expansion) of the optical film of the present invention is preferably 20 ppm or less, more preferably 15 ppm or less, and more preferably 10 ppm or less , And usually above 0 ppm. If CME is equal to or less than the above upper limit, the optical film tends to express excellent water resistance. Furthermore, CME can be measured using a thermomechanical analysis device, and can be measured, for example, by the method described in the Examples. In this specification, the term "water resistance" refers to the ability to suppress swelling or deformation against loads in a humid environment, and water resistance can be evaluated by CME. The lower the CME, the lower the expansion rate of the optical film to moisture and the higher the water resistance.

The use of the optical film of the present invention is not particularly limited, and can be used for various purposes. The optical film of the present invention may be a single layer as described above, or a laminate, and the optical film of the present invention may be used as it is, or it may be used as a laminate further laminated with other films. Furthermore, when the optical film is a laminated body, all layers laminated on one or both sides of the optical film are included as 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, an ultraviolet absorbing layer, a hard coat layer, an undercoat layer, a gas barrier layer, an adhesion 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.

The ultraviolet absorbing layer is a layer with ultraviolet absorbing function, for example, includes 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, commonly known materials can be used. For example, a thermosetting resin composition or a photocuring resin composition can be used. In this case, the thermosetting resin composition or the photocurable resin composition can be polymerized and cured by supplying energy later.

The adhesive layer may also be a layer called Pressure Sensitive Adhesive (PSA) that is attached to an object by pressing. The pressure-sensitive adhesive can be used as an adhesive that is "adhesive at room temperature and adheres to the material to be bonded by light pressure" (JIS K 6800), or it can be a capsule adhesive. The capsule type Adhesives are "adhesives that contain specific components in a protective coating (microcapsule), and can maintain stability until the coating is destroyed by an appropriate method (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 a target hue. The hue adjusting layer is, for example, a layer containing resin and coloring agent. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, red lead, titanyl calcined pigments, ultramarine blue, cobalt aluminate, and carbon black; azo compounds, quinacridone compounds, and anthraquinone Organic pigments such as series compounds, perylene series compounds, isoindolinone series compounds, phthalocyanine series compounds, quinophthalone series compounds, Shilin series compounds, and diketopyrrolopyrrole series compounds; extender pigments such as barium sulfate and calcium carbonate ; And dyes such as basic dyes, acid dyes and mordant dyes.

The refractive index adjustment layer is a layer having a refractive index adjustment function, and for example, is a layer having a refractive index different from that of a single-layer optical film, and a specific refractive index can be given to the optical film. The refractive index adjustment layer may be, for example, a resin layer containing appropriately selected resin and pigments as appropriate, or a metal film. Examples of pigments that adjust the refractive index include silica, alumina, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. The average primary particle size of the pigment may be 0.1 μm or less. By setting the average primary particle size of the pigment to 0.1 μm or less, the diffuse reflection of light passing through the refractive index adjustment layer can be prevented and the decrease in transparency can be prevented. Examples of metals used for the refractive index adjustment layer include titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and silicon nitride. Such as metal oxides or metal nitrides.

In an 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, when the optical film has a functional layer on one side, the protective film may be laminated on the surface on the optical film side or the functional layer side, or on both 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 single functional layer side or on the surface on the two functional layer sides. The protective film is a film for temporarily protecting 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 protective films include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resin films such as polyethylene and polypropylene films. Resin film; acrylic resin film, etc.; 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 can be manufactured by a method including the following steps: (a) The varnish preparation step, which is a step of preparing a liquid containing the above-mentioned polyamide resin (hereinafter referred to as resin varnish); (b) The coating step, which is the step of coating the resin varnish on the substrate to form a coating film; and (c) Optical film forming step, a step of drying the applied liquid (coating film) to form an optical film.

In the varnish preparation step, the varnish is prepared by dissolving the polyamide-based resin in a solvent, adding the additives as necessary, and stirring and mixing.

The solvent used for the preparation of the varnish is not particularly limited as long as it can dissolve the polyamide resin. Examples of the solvent include: amide-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; lactone-based solvents such as γ-butyrolactone and γ-valerolactone Solvents; sulfur-containing solvents such as dimethyl sulfide, dimethyl sulfide, and cyclobutyl sulfide; 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. In addition, the resin varnish may contain water, alcohol solvents, ketone solvents, acyclic ester solvents, ether 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. In addition, in this specification, the solid content of the varnish means the total amount of the components after the solvent is removed from the varnish.

In the coating step, a varnish is applied to the substrate by a known coating method to form a coating film. Examples of well-known coating methods include: wire bar coating, reverse coating, gravure coating and other roll coating methods, die nozzle coating method, cama coating method, die lip coating method, spin coating method, etc. Cloth method, screen coating method, spray coating method, dipping method, spray method, casting method, etc.

In the optical film forming step, the optical film can be formed by drying the coating film and peeling it from the substrate. The drying step of drying the optical film may be further performed after peeling. The drying of the coating film can usually be carried out at a temperature of 50 to 350°C. If necessary, the coating film can be dried in an inert atmosphere or under reduced pressure.

Examples of substrates include: PET (polyethylene terephthalate, polyethylene terephthalate) film, PEN (polyethylene naphthalate, polyethylene naphthalate) film, other polyimide resins or polyamides Amine 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 the optical film and cost, a PET film is more preferred.

[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 viewing 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 these layers is arbitrary, and it is preferable to press the window film, polarizing plate, and touch sensor from the viewing side Or the window film, touch sensor, and polarizer are laminated in order. If there is a polarizer on the side that is more visible than the touch sensor, the pattern of the touch sensor is difficult to be seen, 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 one of the above-mentioned window film, polarizer, and touch sensor.

[Polarizer] As described above, the flexible display device of the present invention preferably further includes a polarizing plate, among which a circular polarizing plate. The circular polarizer is a functional layer that has the function of laminating a λ/4 phase difference plate on the linear polarizer to transmit only the right circular polarized light component or the left circular polarized light component. For example, it is used to block the conversion of external light into right circularly polarized light and reflect it on the organic EL panel to become left circularly polarized outer boundary light, so that only the light-emitting component of the organic EL is transmitted, thereby suppressing the influence of reflected light and making it easier to see the image. In order to realize the circular polarization function, the absorption axis of the linear polarizer and the late axis of the λ/4 retardation plate need to be 45° in theory, but 45±10° in practice. The linear polarizer and the λ/4 retardation plate do not necessarily need to be laminated adjacently, as long as the relationship between the absorption axis and the slow axis satisfies the above range. Although it is preferable to achieve complete circular polarization at the full wavelength, it 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 following function: let light that vibrates along the transmission axis pass through, and block the polarization of the vibration component perpendicular to it. The linear polarizing plate may be a linear polarizing element alone or with a linear polarizing element and a protective film attached to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, preferably 0.5-100 μm. If the thickness of the linear polarizer is in the above range, the flexibility of the linear polarizer tends to be difficult to decrease.

The aforementioned linear polarizing element may be a film-type polarizing element manufactured by dyeing and stretching a polyvinyl alcohol (hereinafter referred to as PVA) film. The dichroic dye such as iodine is adsorbed on the PVA-based film aligned by stretching, or stretched while being adsorbed on the PVA, thereby aligning the dichroic dye and exhibiting polarization performance. In the production of the above-mentioned film-type polarizing element, in addition, steps such as swelling, cross-linking with boric acid, washing with aqueous solution, and drying may be included. The stretching or dyeing step can be performed on the PVA film alone, or 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, a liquid crystal coating type polarizing element formed by applying a liquid crystal polarizing composition can be cited. The liquid crystal polarizing composition may contain 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, and if it has a high-order alignment state such as a smectic, it can exhibit a higher polarization performance, which is preferable. Furthermore, it is preferable that the liquid crystal compound has a polymerizable functional group. The dichroic dye compound is a dye that is aligned with the liquid crystal compound to exhibit dichroism, and may have a polymerizable functional group, and the dichroic dye itself may have liquid crystallinity. Any one of the compounds contained in the liquid crystal polarizing composition has a polymerizable functional group. The above-mentioned liquid crystal polarizing composition may further contain 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 is manufactured by coating a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer. The liquid crystal polarizing layer can be formed thinner than the film-type polarizing element, and the thickness is preferably 0.5-10 μm, more preferably 1-5 μm.

The above-mentioned alignment film is produced, for example, by applying 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 contains an alignment agent, and may further contain a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like. Examples of the alignment agent include polyvinyl alcohols, polyacrylates, polyamides, and polyimines. 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 weight average molecular weight of the polymer used as the above-mentioned alignment agent is, for example, about 10,000 to 1,000,000. The thickness of the aforementioned alignment film is preferably 5 to 10,000 nm, and more preferably 10 to 500 nm in terms of fully exhibiting the alignment restriction force. The liquid crystal polarizing layer may be peeled from the base material and transferred and laminated, or the base material may be directly laminated. The above-mentioned base material is also preferably used as a transparent base material for a protective film, a phase difference plate, and a window film.

The protective film may be a transparent polymer film, and the same materials or additives as those used for the transparent substrate of the window film may be used. In addition, 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 contain plasticizers, ultraviolet absorbers, infrared absorbers, pigments or dyes, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, antistatic agents, antistatic agents, etc. Oxidizers, lubricants, solvents, 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 in the above range, the flexibility of the film tends to be difficult to decrease.

The above-mentioned λ/4 retardation plate is a film that provides a λ/4 retardation in the direction orthogonal to the traveling direction of incident light, in other words, the 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, or a polycarbonate-based film. The above-mentioned λ/4 retardation plate may optionally contain retardation modifiers, plasticizers, ultraviolet absorbers, infrared absorbers, pigments or dyes and other coloring agents, fluorescent whitening agents, dispersants, heat stabilizers, Light stabilizers, antistatic agents, antioxidants, lubricants, solvents, etc. The thickness of the 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 in the above range, the flexibility of the extended phase difference plate tends to be difficult 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 cited. The liquid crystal composition described above contains a liquid crystal compound exhibiting a liquid crystal state such as nematic, cholesteric, and smectic. The liquid crystal compound has a polymerizable functional group. The above-mentioned liquid crystal composition may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coating type retardation plate can be manufactured by applying a liquid crystal composition on a base and curing the liquid crystal composition to form a liquid crystal retardation layer in the same manner as the liquid crystal polarizing layer. The liquid crystal coating type retardation plate can be formed thinner than the extension type retardation plate. The thickness of the liquid crystal polarizing layer is preferably 0.5-10 μm, more preferably 1-5 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 is also preferably used as a transparent base material for a protective film, a phase difference plate, and a window film.

Generally speaking, 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 full visible light region. Therefore, the design is such that the in-plane phase difference is preferably 100-180 nm, and more preferably 130-150 nm, so that the visual sensitivity is higher than 560 nm. Near nm becomes λ/4. The inverse dispersion λ/4 retardation plate using a material with a birefringence wavelength dispersion characteristic opposite to the usual one is better in terms of good visibility. As such a material, for example, an extension type retardation plate can be used as described in JP 2007-232873 A, etc., and a liquid crystal coating type retardation plate can be used as described in JP 2010-30979 A, etc. 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 etc.). The λ/2 phase difference plate is also manufactured using the same material method as the λ/4 phase difference plate. The combination of the extension type retardation plate and the liquid crystal coating type retardation plate is arbitrary, and the thickness can be reduced by using the liquid crystal coating type retardation plate. For the above-mentioned circular polarizing plate, in order to improve the visibility in the oblique direction, a method of laminating positive C plates is known (for example, Japanese Patent Laid-Open No. 2014-224837, etc.). 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] The flexible display device of the present invention preferably further includes a touch sensor as described above. The touch sensor is used as an input mechanism. As the touch sensor, various styles 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 cited, 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 corresponds to the area of the display part where the screen is displayed in the display panel and is an area that senses the user's touch, and the inactive area corresponds to the area of the non-display part where the screen is not displayed in the display device. The touch sensor may include: a substrate having flexibility characteristics; a sensing pattern formed on the active area of the substrate; and each sensing line formed on the inactive area of the substrate for passing through the pad portion Connect the above-mentioned sensing pattern to an external drive circuit. As the substrate with flexibility, 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. 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 through a joint, and the second pattern is a structure in which a plurality of unit patterns are separated from each other in an island shape. Therefore, in order to electrically connect the second pattern, another bridge electrode is required. The electrode used for the connection of the second pattern can be a well-known transparent electrode. As the raw 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 nanotube (CNT), graphene, metal wire, etc. Preferably, ITO can be mentioned. These can be used individually or in mixture of 2 or more types. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, and chromium. These can be used alone or in combination of two or more. The bridge electrode can be formed on the upper part of the insulating layer via the insulating layer on the upper part of the sensing pattern, and the bridge electrode can be formed on the substrate, and the insulating layer and the sensing pattern can be formed thereon. The above-mentioned bridge electrode can also be formed using the same raw material as the sensing pattern, and can also be formed using 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 can also be formed only between the joints of the first pattern and the bridge electrodes, or as a layer covering the entire sensing pattern. When covering the whole 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 as a mechanism for appropriately compensating for the transmission between the pattern area where the sensing pattern is formed and the non-pattern area where the sensing pattern is not formed The difference in rate is specifically the difference in light transmittance induced by the difference in refractive index in these regions. 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 photocuring composition containing a photocuring organic binder and a solvent on the substrate. The 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 contain copolymers of monomers such as acrylate monomers, styrene monomers, and carboxylic acid monomers within a range that does not impair the effects of the present invention. The above-mentioned photocurable organic adhesive may also be a copolymer containing different repeating units such as epoxy-containing repeating units, acrylate repeating units, carboxylic acid repeating units, and the like. Examples of the above-mentioned inorganic particles include zirconium oxide particles, titanium oxide particles, and aluminum oxide particles. The photocurable composition may further contain various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

[Next layer] The window film, circular 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 joined 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 type adhesive, pressure sensitive type adhesive, rewet type adhesive and other commonly used adhesives For example, it is preferable to use an aqueous solvent-volatile adhesive, an active energy ray hardening 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 or type of each 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, and styrene-butadiene emulsions can be used as the main Agent polymer. In addition to the above-mentioned main agent polymer and water, crosslinking agents, silane compounds, ionic compounds, crosslinking catalysts, antioxidants, dyes, pigments, inorganic fillers, organic solvents, etc. can also be formulated. In the case of bonding using the water-based solvent-volatile adhesive, the water-based solvent-volatile adhesive may be injected between the layers to be bonded, and the bonded layers may be bonded and dried to impart adhesiveness. In the case of using the above-mentioned aqueous 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 or type of each layer may be the same or different.

The active energy ray curable adhesive can be formed by curing the active energy ray curable composition containing the reactive material that forms the adhesive layer by irradiating active energy rays. 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 as the radical polymerizable compound in the hard coat composition. The above-mentioned cationically polymerizable compound can be the same as the cationically polymerizable compound in the hard coat composition. The cationic polymerizable compound used in the active energy ray hardening composition is preferably an epoxy compound. In order to reduce the viscosity of the adhesive composition, it is also preferable to contain 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 acrylate-based monomers having one (meth)acrylic acid group in one molecule, or compounds 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 contain a polymerization initiator. Examples of the polymerization initiator include radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, and the like, and these are appropriately selected and used. The polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate free radicals or cations for radical polymerization and cationic polymerization. In the description of the hard coating composition, an initiator that can start at least one of radical polymerization or cationic polymerization by active energy ray irradiation can be used. The active energy ray curable composition may further contain ion scavengers, antioxidants, chain transfer agents, adhesion imparting agents, thermoplastic resins, fillers, flow viscosity modifiers, plasticizers, defoamer solvents, additives, and solvents. In the case of bonding two adhesive layers with the above-mentioned active energy ray-curable adhesive, by applying the above-mentioned active energy ray-curing composition to either or both of the layers to be adhered, Either the bonded layer or the two bonded layers are irradiated with active energy rays to harden and bond. In the case of using the 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 above-mentioned active energy ray hardening adhesive is used for the formation of a plurality of adhesive layers, the thickness or type of each layer may be the same or different.

The above-mentioned adhesives are 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 the adhesive, in addition to the main agent polymer, crosslinking agents, silane-based compounds, ionic compounds, crosslinking catalysts, antioxidants, adhesion imparting agents, plasticizers, dyes, pigments, inorganic fillers, etc. can also be blended. Each component constituting the adhesive is 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 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 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 using multiple layers of the above-mentioned adhesive, the thickness or type of each layer may be the same or different.

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

[Polyamide-based resin] The present invention includes a polyamide-based resin having at least the structural unit represented by formula (1) and the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ . This polyamide-based resin is the same as the polyamide-based resin containing the group represented by formula (3) as Ar ¹ in formula (1) described in the section of <Polyamide-based resin>.

The polyamide resin of the present invention has a structural unit represented by formula (1) in which Ar ¹ is a divalent aromatic group with a specific electron-donating group, so it can form an optical film with excellent surface hardness and water resistance . In addition, the optical film may also have excellent optical properties. [Example]

Hereinafter, the present invention will be explained in more detail using examples. The "%" and "parts" in the example indicate mass% and mass parts unless otherwise stated. First, the evaluation method will be described.

＜Measurement of durability＞ The CME of the optical film obtained in the Examples and Comparative Examples was measured using "TMA/SS6100 Type" manufactured by Hitachi High-Tech Science Co., Ltd. Specifically, in a nitrogen atmosphere, the chuck spacing is set to 10 mm, and an optical film with a width of 2 mm and a length of 20 mm is set on the chuck, and the chuck is maintained under a load of 20 mN, 60°C, and 0% RH until saturation. After that, the temperature was controlled to 60°C and 90% RH and kept for 1 hour, and the humidity linear expansion rate of the optical film at this time was measured. The lower the CME, the lower the expansion rate of the optical film to moisture and the higher the water resistance.

＜Measurement of surface hardness＞ According to JIS K 5600-5-4: 1999, the pencil hardness of the optical film surface obtained in the examples and comparative examples was measured. The load was set to 100 g, the scanning speed was set to 60 mm/min, and the presence or absence of damage was evaluated in an environment of 4,000 lux, and the pencil hardness was measured.

＜Measurement of total light transmittance＞ According to JIS K 7105:1981, the total light transmittance of the optical films obtained in the Examples and Comparative Examples was measured using the automatic direct-reading haze meter HGM-2DP manufactured by Suga Test Instruments Co., Ltd.

＜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 (manufactured by Suga Test Instruments Co., Ltd., "HGM-2DP") (%) is measured.

＜Determination of weight average molecular weight＞ Gel Permeation Chromatography (GPC) determination (1) Pretreatment method To the polyamide resins (samples) obtained in the examples and comparative examples, add DMF (Dimethylformamide) lysate (10 mmol/L lithium bromide solution) so that the concentration becomes 2 mg/mL , Stirring and heating at 80°C for 30 minutes, after cooling, filtering with a 0.45 μm membrane filter, and setting the result as the measurement solution. (2) Measurement conditions Column: TSKgel α-2500 ((7) 7.8 mm diameter × 300 mm) × 1 piece, α-M ((13) 7.8 mm diameter × 300 mm) × 2 pieces manufactured by Tosoh Co., Ltd. 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

＜Measurement of thickness＞ The thickness of the optical film obtained in the Examples and Comparative Examples was measured using a micrometer ("ID-C112XBS" manufactured by Mitutoyo Co., Ltd.).

<Example 1> [Preparation of polyamide resin (1)] Under a nitrogen atmosphere, add 2,2'-bis(trifluoromethyl)benzidine (TFMB) and N,N to a separable flask equipped with a stirring blade so that the solid content of TFMB becomes 5.10% by mass -Dimethylacetamide (DMAc), stirring at room temperature while dissolving TFMB in DMAc. Next, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) was added to the flask so that it became 40.82 mol% with respect to TFMB, and it stirred at room temperature for 3 hours. Then, after cooling to 10°C, 2,5-dimethoxyterephthalate chloride (2MOTPC) was added so as to be 27.55 mol% with respect to TFMB, and after stirring for 10 minutes, it was further increased with respect to TFMB. Add 2MOTPC so that it becomes 27.55 mol%, and stir for 30 minutes. Then, the same amount of DMAc as the DMAc added first was added, and after stirring for 10 minutes, 2MOTPC was added so as to be 6.12 mol% with respect to TFMB, and stirred for 2 hours. Then, 61.22 mol% of diisopropylethylamine and 4-picoline relative to TFMB were added to the flask, and 285.71 mol% of acetic anhydride relative to TFMB were added. 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, and was linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyamide resin (1). The weight average molecular weight of the obtained polyamide resin (1) was 210,000.

[Manufacturing of Optical Film (1)] To the obtained polyamide-based resin (1), DMAc was added so that the concentration became 10% by mass to prepare a polyamide-based resin varnish (1). Using an applicator, apply the obtained polyamide resin varnish (1) 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 50 μm It was dried 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 45 μm.

<Comparative example 1> [Preparation of polyamide resin (2)] Under a nitrogen atmosphere, in a separable flask equipped with a stirring blade, TFMB and DMAc were added so that the solid content of TFMB became 5.35 mass%, and the TFMB was dissolved in DMAc while stirring at room temperature. Next, 6FDA was added to the flask so that it might become 41.24 mol% with respect to TFMB, and it stirred at room temperature for 3 hours. Then, after cooling to 10°C, terephthalic acid chloride (TPC) was added so as to become 27.84 mol% relative to TFMB, and after stirring for 10 minutes, TPC was further added so as to become 27.84 mol% relative to TFMB, Stir for 30 minutes. After that, the same amount of DMAc as the DMAc added first was added, and after stirring for 10 minutes, TPC was added so as to be 6.19 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, 61.86 mol% of diisopropylethylamine and 4-picoline relative to TFMB were added to the flask, and 288.66 mol% of acetic anhydride relative to TFMB was added. 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, and was linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyamide resin (2). The weight average molecular weight of the obtained polyamide resin (2) was 174,000.

[Manufacturing of Optical Film (2)] To the obtained polyamide-based resin (2), DMAc was added so that the concentration became 10% by mass to prepare a polyamide-based resin varnish (2). Using an applicator, apply the obtained polyamide resin varnish (2) 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 It was dried 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 dried at 200° C. for 60 minutes to obtain an optical film (2) with a thickness of 50 μm.

<Example 2> [Preparation of polyamide resin (3)] Under a nitrogen atmosphere, in a separable flask equipped with a stirring blade, TFMB and DMAc were added so that the solid content of TFMB became 5.61% by mass, and stirred at room temperature to dissolve TFMB in DMAc. Next, 6FDA was added to the flask so that it might become 20.20 mol% with respect to TFMB, and it stirred at room temperature for 3 hours. Then, after cooling to 10°C, 2-methoxyterephthalic acid chloride (OMTPC) was added so as to become 36.36 mol% relative to TFMB, and after stirring for 10 minutes, it was further 36.37 mol% relative to TFMB. Add OMTPC in the same way and stir for 30 minutes. After that, the same amount of DMAc as the DMAc added first was added, and after stirring for 10 minutes, OMTPC was added so as to be 8.08 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Then, 80.81 mol% of diisopropylethylamine and 4-picoline relative to TFMB were added to the flask, and 141.41 mol% of acetic anhydride relative to TFMB were added. 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, and was linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Then, the precipitate was dried under reduced pressure at 60°C to obtain a polyamide resin (3). The weight average molecular weight of the obtained polyamide resin (3) was 483,000.

[Manufacturing of Optical Film (3)] To the obtained polyamide-based resin (3), DMAc was added so that the concentration became 10% by mass to prepare a polyamide-based resin varnish (3). Using an applicator, apply the obtained polyamide resin varnish (3) 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 It was dried 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 dried at 200° C. for 60 minutes to obtain an optical film (3) with a thickness of 50 μm.

Table 1 shows the measurement results of CME, pencil hardness, total light transmittance, and haze of the optical films obtained in Examples 1, 2 and Comparative Example 1. [Table 1] CME (ppm) Pencil hardness Total light transmittance (%) Haze (%) Example 1 8 HB 91 0.2 Comparative example 1 25 ＜6B 92 0.2 Example 2 12 HB 91 0.3

As shown in Table 1, it was confirmed that the optical films obtained in Examples 1 and 2 had significantly lower CME and higher pencil hardness than the optical films obtained in Comparative Example 1. Therefore, it can be seen that the optical film of the present invention can have both excellent water resistance and surface hardness.

Claims (14)

An optical film comprising a polyamide resin having at least the structural unit represented by formula (1), [化28]

[In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C1 group which may have a substituent. At least one substituent in the group consisting of an alkoxy group of 12, an aryl group of 6 to 12 carbons that may have a substituent, an aryloxy group of 6 to 12 carbons that may have a substituent, and a hydroxyl group, Ar ² represents a divalent aromatic group which may have a substituent]. The optical film of claim 1, wherein the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ , [化29]

[In formula (3), R ¹ independently represents an alkyl group having 1 to 12 carbons which may have a substituent, an alkoxy group having 1 to 12 carbons which may have a substituent, or a substituted An aryl group or hydroxyl group with 6 to 12 carbon atoms, k and n independently represent an integer of 1 to 4, and when k is 2 or more, R ¹ substituted for different aromatic groups may be the same or different, * means Bonding key]. Such as the optical film of claim 2, wherein in formula (3), the two bonding bonds are positioned opposite each other. An optical film according to any one of claims 1 to 3, wherein the structural unit represented by formula (1) contains the group represented by formula (5) as Ar ² , [化30]

[In formula (5), R ⁹ to R ¹⁶ independently represent 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, R ⁹ to The hydrogen atoms contained in R ¹⁶ may be independently substituted by halogen atoms, and * represents a bonding bond]. The optical film according to any one of claims 1 to 4, wherein the polyamide resin further has a structural unit represented by formula (2), [化31]

[In formula (2), Ar ³ represents a divalent aromatic group having an electron-donating group, and Ar ⁴ and Ar ⁵ independently represent a divalent aromatic group that may also have a substituent. Among them, Ar ³ and the formula When Ar ¹ in (1) is the same and q is 0, Ar ^{4 is} different from Ar ² in formula (1), and W independently represents -O-, diphenylmethylene, -SO ₂ -, -S -, -CO-, -PO-, -PO ₂ -, -N(R ²¹ )-, -Si(R ²² ) ₂ -or a divalent hydrocarbon group with 1 to 12 carbons, the hydrogen atom contained in the hydrocarbon group It may be independently substituted by a halogen atom, or two hydrogen atoms may be substituted to form a ring. R ²¹ and R ²² independently represent a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms which may be substituted by a halogen atom. q represents an integer of 0-4]. The optical film of any one of claims 2 to 5, wherein in formula (3), R ¹ independently represents an alkyl group having 1 to 6 carbons or an alkoxy group having 1 to 6 carbons, k and n Stands for 1 or 2 independently of each other. The optical film according to any one of claims 2 to 5, wherein in formula (3), R ¹ represents an alkoxy group having 1 to 6 carbon atoms, k represents 1, and n represents 1 or 2. The optical film of any one of claims 4 to 7, wherein formula (5) is represented by formula (6), [化32]

[In formula (6), * represents a bonding bond]. The optical film of any one of claims 1 to 8, wherein the polyamide-based resin further has a structural unit represented by formula (5), [化33]

[In formula (5), X represents a divalent organic group, and Y represents a tetravalent organic group]. The optical film of any one of claims 1 to 9 has a thickness of 10 to 200 μm. A flexible display device provided with the optical film as claimed in any one of claims 1 to 10. For example, the flexible display device of claim 11 further includes a touch sensor. For example, the flexible display device of claim 11 or 12 further includes a polarizing plate. A polyamide resin, which has at least the structural unit represented by formula (1), [化34]

[In the formula (1), Ar ¹ represents a divalent aromatic group, and the divalent aromatic group has a C1-C12 alkyl group selected from the group which may have a substituent, and a C1-C1 group which may have a substituent. At least one substituent in the group consisting of an alkoxy group of 12, an aryl group of 6 to 12 carbons that may have a substituent, an aryloxy group of 6 to 12 carbons that may have a substituent, and a hydroxyl group, Ar ² represents a divalent aromatic group that may also have a substituent], and the structural unit represented by formula (1) contains the group represented by formula (3) as Ar ¹ , [化35]

[In formula (3), R ¹ independently represents an alkyl group having 1 to 12 carbons which may have a substituent, an alkoxy group having 1 to 12 carbons which may have a substituent, or a substituted An aryl group or hydroxyl group with 6 to 12 carbon atoms, k and n independently represent an integer of 1 to 4, and when k is 2 or more, R ¹ substituted for different aromatic groups may be the same or different, * means Bonding key].