JP2021115860A - Film roll - Google Patents

Abstract

To provide a method for preventing occurrence of curling in rewinding or greatly reducing curling even if a laminate film is curled even when the laminate film is conveyed and transported as a film roll.SOLUTION: A film roll is obtained by winding an optical film containing a polyimide-based resin and/or a polyamide-based resin, a laminate film containing a cured resin layer having a function laminated on the optical film, and a protective film 1 laminated on a side opposite to the optical film of the cured resin layer. In the film roll, the optical film, the cured resin layer and the protective film 1 are wound in this order from a core side of the roll.SELECTED DRAWING: None

Description

The present invention relates to a film roll in which a laminated film is wound, particularly a film roll in which curling is unlikely to occur when the laminated film is unwound.

Laminated films in which an optical film containing a polyimide resin and / or a polyamide resin and a cured resin layer having a specific function are laminated are used in various fields. For example, a laminated film in which an optical resin film layer containing a polyimide resin and / or a polyamide resin and a hard coat layer are laminated has been conventionally used as the display of various image display devices has become thinner, lighter, and more flexible. It is used as a material to replace the glass used.

Usually, these laminated films are wound around a roll core and transported and transported in the form of a film roll after the laminated film is manufactured. Naturally, when the laminated film is used, it is rewound from the film roll and used as a flat laminated film.

However, curling may occur when the film roll is rewound and used. The curl means that when one surface of the laminated film is placed on a flat surface, the end portion of the laminated film is separated from the flat surface. If the laminated film is curled, it is difficult to use it as it is. Therefore, it is necessary to return the laminated film to a state without curl, which causes a loss in work and deteriorates work efficiency. In addition, the occurrence of curl means that when the film is used in a flat state, a force that separates it from the flat surface acts, which may have an adverse effect on the product using the laminated film. Specifically, when bonding with other members, the curled part may not be bonded well and air bubbles may be caught in it, or when bonding while sucking the film, if the curl is strong, suction cannot be performed and the suction part There was a problem that it peeled off from the film, an error occurred, and the device stopped. The laminated film is made into a film roll during transportation and transportation, but when it is rewound and the laminated film is used, it is preferable that curl does not occur.

Patent Document 1 discloses a printing plate material having a hydrophilic layer on a support, the support is made of a plastic film, and the rising curl is 0 mm or more and 60 mm or less. Patent Document 1 also proposes to reduce the curl, but the method is to perform sequential biaxial stretching in which the curl is stretched in the vertical direction after casting and then further stretched in the horizontal direction, and stretching work is required at the time of manufacturing. Yes, leading to an increase in manufacturing costs.

Japanese Unexamined Patent Publication No. 2004-74502

The present invention provides a simple method in which even when the laminated film is transported and transported as a film roll, there is no curl at the time of rewinding, or even if there is curl, the amount of curl is very small. The purpose.

That is, the present invention relates to an optical film containing a polyimide resin and / or a polyamide resin.
A laminated film containing a cured resin layer laminated on the optical film, and
A film roll formed by winding a laminate containing a protective film 1 laminated on the opposite side of the cured resin layer to the optical film.
The film roll provides a film roll in which an optical film, a cured resin layer, and a protective film 1 are wound in this order from the core side of the roll.

The present invention further provides the following aspects:
The present invention relates to a laminated film containing an optical film containing a polyimide resin and / or a polyamide resin.
The cured resin layer laminated on the optical film and
A protective film 1 laminated on the opposite side of the cured resin layer to the optical film,
A film roll formed by winding a laminate containing a protective film 2 laminated on the opposite side of the cured resin layer of the optical film.
The film roll also provides a film roll in which the protective film 2, the optical film, the cured resin layer, and the protective film 1 are wound in this order from the core side of the roll.
The cured resin layer has one or more functions selected from the group consisting of a hard coat function, an antistatic function, an antiglare function, a low reflection function, an antireflection function and an antifouling function.
The cured resin layer is a UV curable resin layer.

In the present invention, curling of the laminated film can be prevented only by restricting the order in which the laminated body is wound around the roll core, and curling can be easily prevented without affecting the manufacturing method or the like. It can be said that it is an excellent method. In particular, curling during storage, transportation, and transportation in a high temperature environment can be suppressed.

The curl in the present invention is intended to curl when the film roll is stored in a high temperature environment, particularly in a high temperature drying environment. In the present application, the high temperature environment means a temperature environment of about 40 to 100 ° C., and the dry environment means an environment of 0 to 60% relative humidity.

In the present invention, an optical film containing a polyimide resin and / or a polyamide resin, a cured resin layer laminated on the optical film, and a protective film 1 laminated on the opposite side of the cured resin layer to the optical film. In a film roll in which a laminated film containing It is characterized by that. The protective film may be present on the side opposite to the cured resin layer of the optical film. In that case, the order of rotation is from the core side of the roll to the protective film 2, the optical film, the cured resin layer, and the protective film 1. do. Each configuration will be described below.

<Optical film>
The optical film constituting the laminated film of the present invention contains a polyimide-based resin and / or a polyamide-based resin.

In the present specification, the polyimide-based resin represents at least one resin selected from the group consisting of a polyimide resin, a polyamide-imide resin, a polyimide precursor resin, and a polyamide-imide precursor resin. The polyimide resin is a resin containing a repeating structural unit containing an imide group, and the polyamide-imide resin is a resin containing a repeating structural unit containing both an imide group and an amide group. The polyimide precursor resin and the polyamide-imide precursor resin are pre-imidization precursors that give the polyimide resin and the polyamide-imide resin by imidization, respectively, and are also called polyamic acids. Further, in the present specification, the polyamide-based resin is a resin containing a repeating structural unit containing an amide group. The optical film of the present invention may contain one type of polyimide resin or polyamide-based resin, or may contain two or more types of polyimide-based resin and / or polyamide-based resin in combination. The optical film of the present invention preferably contains a polyimide resin from the viewpoint of easily achieving both chemical stability and curl resistance of the optical film, and the polyimide resin is preferably a polyimide resin or a polyamide imide resin. , More preferably a polyimideimide resin.

In a preferred embodiment of the present invention, the polyimide resin and the polyamide resin are preferably aromatic resins from the viewpoint of easily increasing the elastic modulus and curl resistance of the optical film. In the present specification, the aromatic resin refers to a resin in which the constituent unit contained in the polyimide resin and the polyamide resin is mainly an aromatic constituent unit.

In one preferred embodiment described above, from the viewpoint of easily increasing the elastic modulus and curl resistance of the optical film, the ratio of the structural units derived from the aromatic monomer to the total structural units contained in the polyimide resin and the polyamide resin is It is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and particularly preferably 85 mol% or more. Here, the structural unit derived from the aromatic monomer is derived from a monomer having an aromatic structure, for example, an aromatic ring in at least a part thereof, and contains an aromatic structure, for example, an aromatic ring in at least a part. It is a structural unit. Examples of the aromatic monomer include aromatic tetracarboxylic acid compounds, aromatic diamines, aromatic dicarboxylic acids and the like.

In one preferred embodiment of the present invention, the polyimide resin is based on the formula (1):

［式（１）中、Ｙは４価の有機基を表し、Ｘは２価の有機基を表し、＊は結合手を表す］
で表される構成単位を有するポリイミド樹脂であるか、又は、式（１）で表される構成単位及び式（２）：

[In formula (1), Y represents a tetravalent organic group, X represents a divalent organic group, and * represents a bond]
It is a polyimide resin having a structural unit represented by, or a structural unit represented by the formula (1) and the formula (2):

［式（２）中、Ｚ及びＸは、互いに独立に、２価の有機基を表し、＊は結合手を表す］
で表される構成単位を有するポリアミドイミド樹脂であることが好ましい。また、ポリアミド系樹脂は、式（２）で表される構成単位を有するポリアミド樹脂であることが好ましい。以下において式（１）及び式（２）について説明するが、式（１）についての説明は、ポリイミド樹脂及びポリアミドイミド樹脂の両方に関し、式（２）についての説明は、ポリアミド樹脂及びポリアミドイミド樹脂の両方に関する。

[In formula (2), Z and X represent divalent organic groups independently of each other, and * represents a bond]
It is preferable that the polyamide-imide resin has a structural unit represented by. Further, the polyamide resin is preferably a polyamide resin having a structural unit represented by the formula (2). The formulas (1) and (2) will be described below, but the description of the formula (1) relates to both the polyimide resin and the polyamide-imide resin, and the description of the formula (2) describes the polyamide resin and the polyamide-imide resin. Regarding both.

The structural unit represented by the formula (1) is a structural unit formed by reacting a tetracarboxylic acid compound and a diamine compound, and the structural unit represented by the formula (2) is a dicarboxylic acid compound and a diamine compound. Is a structural unit formed by the reaction of and.

In the formula (2), Z is a divalent organic group, preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms (these groups). The hydrogen atom in the above is a divalent organic group having 4 to 40 carbon atoms, which may be substituted with a halogen atom (preferably a fluorine atom), and more preferably 1 to 6 carbon atoms. Alkyl group, alkoxy group having 1 to 6 carbon atoms, or aryl group having 6 to 12 carbon atoms (the hydrogen atom in these groups may be substituted with a halogen atom (preferably a fluorine atom)). It may be a divalent organic group having a cyclic structure and having 4 to 40 carbon atoms. Examples of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms include examples relating to ^{R 3a} and R ^{3b in the formula (3) described later.} The same applies. Examples of the cyclic structure include an alicyclic ring, an aromatic ring, and a heterocyclic structure. As the organic group of Z, the formula (20), the formula (21), the formula (22), the formula (23), the formula (24), the formula (25), the formula (26), the formula (27), the formula (28). And equation (29):

［式（２０）〜式（２９）中、Ｗ^１は、単結合、−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−又は−Ａｒ−ＳＯ_２−Ａｒ−を表し、ここで、Ａｒは、互いに独立に、水素原子がフッ素原子で置換されていてもよい炭素数６〜２０のアリーレン基（例えばフェニレン基）を表し、＊は結合手を表す］
で表される基の結合手のうち、隣接しない２つが水素原子に置き換わった基及び炭素数６以下の２価の鎖式炭化水素基が例示され、Ｚのヘテロ環構造としてはチオフェン環骨格を有する基が例示される。光学フィルムの黄色度の指標であるＹＩ値を低減しやすい観点から、式（２０）〜式（２９）で表される基、及び、チオフェン環骨格を有する基が好ましく、式（２６）、式（２８）及び式（２９）で表される基がより好ましい。

Wherein (20) to Formula (29), ^{W 1} represents a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) _{2 -, - C (CF 3} ) 2 -, - Ar -, - SO 2 -, - CO -, - O-Ar-O -, - Ar-O-Ar -, - Ar-CH 2 -Ar-, Represents -Ar-C (CH ₃ ) _2- Ar- or -Ar-SO _2- Ar-, where Ar has 6 to 6 carbon atoms in which a hydrogen atom may be substituted with a fluorine atom independently of each other. Represents 20 arylene groups (eg phenylene groups), * represents a bond]
Among the group bonds represented by, a group in which two non-adjacent groups are replaced with hydrogen atoms and a divalent chain hydrocarbon group having 6 or less carbon atoms are exemplified, and the heterocyclic structure of Z is a thiophene ring skeleton. The group having is exemplified. From the viewpoint of easily reducing the YI value, which is an index of the yellowness of the optical film, the groups represented by the formulas (20) to (29) and the groups having a thiophene ring skeleton are preferable, and the formulas (26) and the formula (26) are preferable. The groups represented by (28) and (29) are more preferable.

Examples of the organic group of Z include the formula (20'), the formula (21'), the formula (22'), the formula (23'), the formula (24'), the formula (25'), the formula (26'), and the formula. (27'), equation (28') and equation (29'):

［式（２０’）〜式（２９’）中、Ｗ^１及び＊は、式（２０）〜式（２９）において定義した通りである］
で表される２価の有機基がより好ましい。なお、式（２０）〜式（２９）及び式（２０’）〜式（２９’）における環上の水素原子は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、又は炭素数６〜１２のアリール基（これらの基における水素原子はハロゲン原子（好ましくはフッ素原子）で置換されていてもよい）で置換されていてもよい。

In formula (20 ') to formula (29'), ^{W 1} and * are as defined in formula (20) to (29)]
The divalent organic group represented by is more preferable. The hydrogen atom on the ring in the formulas (20) to (29) and the formulas (20') to (29') is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. It may be substituted with an aryl group having 6 to 12 carbon atoms (the hydrogen atom in these groups may be substituted with a halogen atom (preferably a fluorine atom)).

When the polyamide-based resin or the polyamide-imide resin has a structural unit in which Z in the formula (2) is represented by any of the above formulas (20') to (29'), particularly in the formula (2). When Z has a structural unit represented by the formula (3') described later, the polyamide-based resin or the polyamide-imide resin is added to the structural unit and has the following formula (d1):

［式（ｄ１）中、Ｒ^２４は後述する式（３）中のＲ^３ａについて定義する基又は水素原子であり、Ｒ^２５は、Ｒ^２４又は−Ｃ（＝Ｏ）−＊を表し、＊は結合手を表す］
で表されるカルボン酸由来の構成単位をさらに有することが、ワニスの成膜性を高めやすく、光学フィルムの均一性を高めやすい観点から好ましい。構成単位（ｄ１）としては、具体的には、Ｒ^２４及びＲ^２５がいずれも水素原子である構成単位（ジカルボン酸化合物に由来する構成単位）、Ｒ^２４がいずれも水素原子であり、Ｒ^２５が−Ｃ（＝Ｏ）−＊を表す構成単位（トリカルボン酸化合物に由来する構成単位）等が挙げられる。

[In the formula (d1), R ²⁴ is a group or a hydrogen atom defining ^{R 3a} in the formula (3) described later ^{, R 25} represents R ²⁴ or −C (= O) − *, and * represents R 24 or −C (= O) − *. Representing a join hand]
It is preferable to further have a carboxylic acid-derived structural unit represented by (1) from the viewpoint of easily improving the film-forming property of the varnish and easily improving the uniformity of the optical film. Specifically, as the structural unit (d1) ^{, a structural unit in which both R 24} and R ²⁵ are hydrogen atoms (a structural unit derived from a dicarboxylic acid compound) and R ²⁴ are both hydrogen atoms, and R ^25. Examples thereof include a structural unit (a structural unit derived from a tricarboxylic acid compound) representing −C (= O) − *.

The polyamide-based resin or the polyamide-imide resin may contain a plurality of types of Z as Z in the formula (2), and the plurality of types of Z may be the same as or different from each other. Above all, Z in the formula (2) is preferably used from the viewpoint that the elastic modulus and curl resistance of the optical film of the present invention can be easily improved and the optical characteristics can be easily improved.

［式（３）中、Ｒ^３ａ及びＲ^３ｂは、互いに独立に、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、又は炭素数６〜１２のアリール基を表し、Ｒ^３ａ及びＲ^３ｂに含まれる水素原子は、互いに独立に、ハロゲン原子で置換されていてもよく、
Ｗは、互いに独立に、単結合、−Ｏ−、−ＣＨ_２−、−ＣＨ_２−ＣＨ_２−、−ＣＨ（ＣＨ_３）−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−Ｓ−、−ＣＯ−又は−Ｎ（Ｒ^９）−を表し、Ｒ^９は水素原子、ハロゲン原子で置換されていてもよい炭素数１〜１２の１価の炭化水素基を表し、
ｓは０〜４の整数であり、ｔは０〜４の整数であり、ｕは０〜４の整数であり、＊は結合手を表す］
、より好ましくは式（３’）：

[In the formula (3), R ^3a and R ^3b independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ^3a. And the ^{hydrogen atoms contained in R 3b} may be substituted with halogen atoms independently of each other.
W, independently of one another, a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, - C (CF 3) _{2 -, - SO 2 -,} - S -, - CO- or -N ^{(R 9)} - represents, ^{R 9} is a hydrogen atom, monovalent 1-12 carbon atoms which may be substituted with a halogen atom Represents a hydrocarbon group
s is an integer from 0 to 4, t is an integer from 0 to 4, u is an integer from 0 to 4, and * represents a bond.]
, More preferably equation (3'):

［式（３’）中、Ｒ^３ａ、Ｒ^３ｂ、ｓ、ｔ、ｕ、Ｗ及び＊は、式（３）において定義した通りである］
で表される構成単位を少なくとも有することが好ましい。なお、本明細書において、ポリアミド系樹脂又はポリアミドイミド樹脂が式（２）中のＺが式（３）で表される構成単位を有することと、ポリアミド系樹脂又はポリアミドイミド系樹脂が式（２）中のＺとして式（３）で表される構造を有することとは、同様の意味を有し、ポリアミド系樹脂又はポリアミドイミド樹脂に含まれる複数の式（２）で表される構成単位のうち、少なくとも一部の構成単位におけるＺが式（３）で表されることを意味する。当該記載は、他の同様の記載にもあてはまる。

[In equation (3'), R ^3a , R ^3b , s, t, u, W and * are as defined in equation (3)]
It is preferable to have at least a structural unit represented by. In the present specification, the polyamide-based resin or the polyamide-imide resin has a structural unit in which Z in the formula (2) is represented by the formula (3), and the polyamide-based resin or the polyamide-imide resin has the formula (2). ) Has the same meaning as having a structure represented by the formula (3) as Z, and is a structural unit represented by a plurality of formulas (2) contained in the polyamide-based resin or the polyamide-imide resin. Of these, it means that Z in at least a part of the constituent units is represented by the equation (3). This statement also applies to other similar statements.

In formulas (3) and (3 '), W, independently of one another, a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C ( CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -N (R ⁹ )-, preferably from the viewpoint of bending resistance of the optical film. It represents −O− or −S−, more preferably −O−.
R ^3a and R ^3b independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and 2 -Methyl-butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group and the like can be mentioned. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group and a hexyloxy group. Groups, cyclohexyloxy groups and the like can be mentioned. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xsilyl group, a naphthyl group, a biphenyl group and the like. From the viewpoint of the surface hardness and flexibility of the optical film, R ^3a and R ^3b independently represent an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Here, the ^{hydrogen atoms contained in R 3a} and R ^3b may be substituted with halogen atoms independently of each other.
R ⁹ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. Examples of monovalent hydrocarbon groups having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and n-. Pentyl group, 2-methyl-butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl, n-heptyl group, n-octyl group, tert-octyl group, n-nonyl group, n-decyl group Etc., and these may be substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

In the formula (3) and the formula (3'), t and u are independently integers of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. ..

In the formula (3) and the formula (3'), s is an integer in the range of 0 to 4, and when s is in this range, the curl resistance, elastic modulus and bending resistance of the optical film are improved. Cheap. The s is preferably an integer in the range of 0 to 3, more preferably an integer in the range of 0 to 2, and even more preferably 0, from the viewpoint of easily improving the curl resistance, elastic modulus and bending resistance of the optical film. Or 1, especially preferably 0. The structural unit represented by the formula (3) or the formula (3') in which s is 0 is, for example, a structural unit derived from terephthalic acid or isophthalic acid, and the structural unit is the formula (3) or the formula (3). It is preferable that s in') is 0 and u is 0. From the viewpoint of easily improving the curl resistance, elastic modulus and bending resistance of the optical film, the polyamide-imide resin or the polyamide-based resin preferably contains a structural unit derived from terephthalic acid. The polyamide-imide resin or the polyamide-based resin may contain one or more structural units represented by the formula (3) or the formula (3') in Z. From the viewpoint of improving the curl resistance, elastic modulus and bending resistance of the optical film, and reducing the YI value, the polyamide-imide resin or the polyamide-based resin is Z in formula (3) or s in formula (3'). It is preferable to include two or more types of structural units having different values, and more preferably to include two or three types of structural units having different values of s in the formula (3) or the formula (3'). In this case, the polyamide-imide resin or the polyamide-based resin is represented by the formula (2) from the viewpoint of easily increasing the curl resistance, elastic modulus and bending resistance of the optical film and easily reducing the YI value of the optical film. Z in the structural unit includes a structure represented by the formula (3) in which s is 0, and includes a structure represented by the formula (3) in which s is 1 in addition to the structural unit containing the structure. It is more preferable to further contain a structural unit. Further, in addition to the structural unit represented by the formula (2) having Z represented by the formula (3) in which s is 0, it is also preferable to further have the structural unit represented by the above formula (d1). ..

In a preferred embodiment of the present invention, the polyamide-imide resin or the polyamide-based resin is a structural unit having s = 0 and u = 0 as a structural unit represented by the formula (3) or the formula (3'). Has. In a more preferable embodiment of the present invention, the polyamide-imide resin or the polyamide-based resin has a configuration in which s = 0 and u = 0 as a structural unit represented by the formula (3) or the formula (3'). Unit and formula (3 "):

で表される構成単位を有する。この場合、光学フィルムの耐カール性、弾性率及び耐屈曲性を向上させやすいと共に、ＹＩ値を低減しやすい。

It has a structural unit represented by. In this case, it is easy to improve the curl resistance, elastic modulus and bending resistance of the optical film, and it is easy to reduce the YI value.

When the polyamideimide resin or the polyamide-based resin has a structural unit represented by the formula (3) or the formula (3'), the ratio thereof is the configuration represented by the formula (1) of the polyamideimide resin or the polyamide-based resin. When the total of the units and the constituent units represented by the formula (2) is 100 mol%, it is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably. It is 50 mol% or more, particularly preferably 60 mol% or more, preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less. When the ratio of the structural units represented by the formula (3) or the formula (3') is at least the above lower limit, the curl resistance, elastic modulus and bending resistance of the optical film can be easily increased. When the ratio of the constituent units represented by the formula (3) or the formula (3') is not more than the above upper limit, the increase in the viscosity of the resin-containing varnish due to the hydrogen bond between the amide bonds derived from the formula (3) is suppressed, and the film is formed. It is easy to improve the workability of.

Further, when the polyamide-imide resin or the polyamide-based resin has a structural unit represented by the formula (3) or the formula (3') in which s = 1 to 4, the formula (3) or the formula in which s is 1 to 4 is obtained. The ratio of the structural units represented by (3') is 100 mol%, which is the total of the structural units represented by the formula (1) and the structural units represented by the formula (2) of the polyamide-imide resin or the polyamide-based resin. When it is, it is preferably 3 mol% or more, more preferably 5 mol% or more, further preferably 7 mol% or more, particularly preferably 9 mol% or more, preferably 90 mol% or less, more preferably 70 mol% or more. Below, it is more preferably 50 mol% or less, and particularly preferably 30 mol% or less. When the ratio of the structural units represented by the formula (3) or the formula (3') in which s is 1 to 4 is not more than the above lower limit, the curl resistance, elastic modulus and bending resistance of the optical film can be easily improved. .. When the ratio of the structural unit represented by the formula (3) in which s is 1 to 4 is not more than the above upper limit, the hydrogen between amide bonds derived from the structural unit represented by the formula (3) or the formula (3') It is easy to improve the processability of the film by suppressing the increase in viscosity of the resin-containing varnish due to bonding. The ratio of the structural units represented by the formula (1), the formula (2), the formula (3) or the formula (3') ^{can be measured by using, for example, 1 1} H-NMR, or the raw material is charged. It can also be calculated from the ratio.

In a preferred embodiment of the present invention, preferably 30 mol% or more, more preferably 40 mol% or more, still more preferably 45 mol% or more, still more preferably 50 mol% of Z in the polyamide-imide resin or the polyamide-based resin. % Or more is a structural unit represented by the formula (3) or the formula (3') in which s is 0 to 4. When the above lower limit of Z or more is a structural unit represented by the formula (3) or the formula (3') in which s is 0 to 4, the curl resistance, elastic modulus and bending resistance of the optical film are enhanced. Cheap. Further, 100 mol% or less of Z in the polyamide-imide resin or the polyamide-based resin may be a structural unit represented by the formula (3) or the formula (3') in which s is 0 to 4. The ratio of the structural units represented by the formula (3) or the formula (3') in which s is 0 to 4 in the resin ^{can be measured by using, for example, 1 1} H-NMR, or the raw material. It can also be calculated from the charge ratio.

In a preferred embodiment of the present invention, preferably 5 mol% or more, more preferably 8 mol% or more, still more preferably 10 mol% or more, and particularly preferably 12 mol% or more of Z in the polyamide-imide resin or the polyamide-based resin. The above is represented by the formula (3) or the formula (3') in which s is 1 to 4. When the above lower limit or more of Z of the polyamide-imide resin or the polyamide-based resin is represented by the formula (3) or the formula (3') in which s is 1 to 4, the curl resistance, elastic modulus and resistance of the optical film are expressed. Easy to increase flexibility. Further, the formula (3) or formula (3) or formula in which s is 1 to 4, preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and particularly preferably 30 mol% or less of Z. It is represented by (3'). When the above upper limit or less of Z is represented by the formula (3) in which s is 1 to 4, it is derived from the structural unit represented by the formula (3) or the formula (3') in which s is 1 to 4. It is easy to improve the processability of the film by suppressing the increase in viscosity of the resin-containing varnish due to the hydrogen bond between the amide bonds. The ratio of the structural units represented by the formula (3) or the formula (3') in which s is 1 to 4 in the resin ^{can be measured by using, for example, 1 1} H-NMR, or the raw material charging ratio. It can also be calculated from.

In formulas (1) and (2), X is a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms, more preferably a cyclic structure having 4 to 40 carbon atoms, independently of each other. Represents a divalent organic group of. Examples of the cyclic structure include an alicyclic ring, an aromatic ring, and a heterocyclic structure. In the organic group, the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with fluorine, in which case the number of carbon atoms of the hydrocarbon group and the hydrocarbon group substituted with fluorine is preferable. Is 1 to 8. In one embodiment of the present invention, the polyamide-imide resin of the present invention may contain a plurality of types of X, and the plurality of types of X may be the same as or different from each other. X is represented by the formula (10), the formula (11), the formula (12), the formula (13), the formula (14), the formula (15), the formula (16), the formula (17) and the formula (18). Groups; Groups in which the hydrogen atom in the groups represented by the formulas (10) to (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and a chain having 6 or less carbon atoms. The formula hydrocarbon group is exemplified.

In equations (10) to (18), * represents a bond,
V ^{1, V 2} and ^{V 3} independently of one another, a single _{bond, -O -, - S -,} - CH 2 -, - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH ₃ ) _{Represents 2-} , -C (CF ₃ ) _2- , -SO _2- , -CO- or -N (Q)-. Here, Q represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include the groups mentioned above for R ^9.
In one example, V ¹ and V ³ are single bonds, -O- or -S-, and V ² is -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2. -Or -SO _2- . The ^{bonding positions of V 1} and V ² with respect to each ring and the bonding positions of V ² and V ³ with respect to each ring are independent of each other, preferably in the meta position or para position with respect to each ring, and more preferably in the para position. It is a place.

Among the groups represented by the formulas (10) to (18), the formulas (13), (14), and (15) are used from the viewpoint of easily increasing the curl resistance, elastic modulus, and bending resistance of the optical film. , The groups represented by the formulas (16) and (17) are preferable, and the groups represented by the formulas (14), (15) and (16) are more preferable. Further, V ¹ , V ² and V ³ are independent of each other, preferably single bond, -O- or -S-, more preferably, from the viewpoint of easily increasing the curl resistance, elastic modulus and flexibility of the optical film. Single bond or -O-.

In a preferred embodiment of the present invention, the polyamide-based resin and the polyimide-based resin are represented by X in the formula (1) or X in the formula (2), and the formula (4):

［式（４）中、Ｒ^１０〜Ｒ^１７は、互いに独立に、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基又は炭素数６〜１２のアリール基を表し、Ｒ^１０〜Ｒ^１７に含まれる水素原子は、互いに独立に、ハロゲン原子で置換されていてもよく、＊は結合手を表す］
で表される構造を含む。式（１）及び式（２）で表される複数の構成単位中のＸの少なくとも一部が式（４）で表される構造であると、光学フィルムの耐カール性、弾性率及び透明性を高めやすい。

[In formula (4), R ^{10 to} R ¹⁷ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. The ^{hydrogen atoms contained in R 10 to} R ¹⁷ may be substituted with halogen atoms independently of each other, and * represents a bond.]
Includes the structure represented by. When at least a part of X in the plurality of structural units represented by the formulas (1) and (2) has a structure represented by the formula (4), the curl resistance, elastic modulus and transparency of the optical film Easy to increase.

In formula (4), R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are independent of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and 1 carbon atom. Represents an alkoxy group of ~ 6 or an aryl group of 6-12 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms include the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms in the formula (3). Examples thereof include groups exemplified as groups or aryl groups having 6 to 12 carbon atoms. R ^{10 to} R ¹⁷ represent independently of each other, preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably an hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and here, R ^{10 to} R ¹⁷ The hydrogen atoms contained in the above may be substituted with halogen atoms independently of each other. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. R ^{10 to} R ¹⁷ are more preferably hydrogen atom, methyl group, fluoro group, chloro group or trifluoromethyl group independently of each other from the viewpoint of curl resistance, elasticity, transparency and bending resistance of the optical film. R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are hydrogen atoms, and R ¹¹ and R ¹⁷ are hydrogen atoms, methyl groups, fluorogroups, chloro groups or trifluoromethyl groups. Of particular preference are R ¹¹ and R ¹⁷ being methyl or trifluoromethyl groups.

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

で表される構成単位であり、すなわち、式（１）及び式（２）で表される複数の構成単位中のＸの少なくとも一部は、式（４’）で表される構成単位である。この場合、フッ素元素を含有する骨格によりポリイミド系樹脂又はポリアミド系樹脂の溶媒への溶解性を高め、該樹脂を含有するワニスの保管安定性を向上しやすいと共に、該ワニスの粘度を低減しやすく、光学フィルムの加工性を向上しやすい。また、フッ素元素を含有する骨格により、光学フィルムの光学特性を向上しやすい。

That is, at least a part of X in the plurality of structural units represented by the formulas (1) and (2) is the structural unit represented by the formula (4'). .. In this case, the skeleton containing a fluorine element enhances the solubility of the polyimide resin or the polyamide resin in the solvent, and it is easy to improve the storage stability of the varnish containing the resin, and it is easy to reduce the viscosity of the varnish. , It is easy to improve the workability of the optical film. Further, the skeleton containing a fluorine element makes it easy to improve the optical characteristics of the optical film.

In a preferred embodiment of the present invention, the formula (4), preferably 30 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, of X in the polyimide resin or the polyamide resin. In particular, it is represented by the equation (4'). When X in the above range in the polyimide resin or the polyamide resin is represented by the formula (4), particularly the formula (4'), the obtained optical film is dissolved in the solvent of the resin by the skeleton containing a fluorine element. It is easy to improve the property and improve the storage stability of the varnish containing the resin, and it is easy to reduce the viscosity of the varnish and improve the processability of the optical film. Further, the skeleton containing a fluorine element makes it easy to improve the optical characteristics of the optical film. It should be noted that preferably, 100 mol% or less of X in the polyimide resin or the polyamide resin is represented by the formula (4), particularly the formula (4'). X in the resin may be of formula (4), especially of formula (4'). The ratio of the structural unit represented by the formula (4) of X in the resin ^{can be measured by using, for example, 1 1} H-NMR, or can be calculated from the charging ratio of the raw materials.

In the formula (1), Y represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms, and more preferably a tetravalent organic group having a cyclic structure and having 4 to 40 carbon atoms. show. Examples of the cyclic structure include an alicyclic ring, an aromatic ring, and a heterocyclic structure, and an aromatic ring is preferable from the viewpoint of easily increasing curl resistance and elastic modulus. The organic group is an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, in which case the hydrocarbon group and the fluorine-substituted hydrocarbon group The number of carbon atoms is preferably 1-8. In one embodiment of the present invention, the polyimide resin may contain a plurality of types of Y, and the plurality of types of Y may be the same as or different from each other. As Y, the following formulas (20), formulas (21), formulas (22), formulas (23), formulas (24), formulas (25), formulas (26), formulas (27), formulas (28) And a group represented by the formula (29); a group in which the hydrogen atom in the groups represented by the formulas (20) to (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; In addition, a chain hydrocarbon group having 4 or less valences of 6 carbon atoms is exemplified.

In the formula (20) to (29), * represents a bond, ^{W 1} is a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -Ar-, -SO _2- , -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar- _{CH 2 -Ar -, - Ar-} C (CH 3) represents a 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 with a fluorine atom, and specific examples thereof include a phenylene group.

Among the groups represented by the formulas (20) to (29), the formula (26), the formula (28) or the formula (29) from the viewpoint of easily increasing the curl resistance, elastic modulus and bending resistance of the optical film. The group represented by the formula (26) is preferable, and the group represented by the formula (26) is more preferable. Further, W ¹ is independent of each other, preferably single bond, −O−, − from the viewpoint of easily increasing the curl resistance, elastic modulus and bending resistance of the optical film and easily reducing the YI value of the optical film. CH _2- , -CH _{2- CH 2-,} -CH (CH ₃ )-, -C (CH ₃ ) _2- or -C (CF ₃ ) _2- , more preferably single bond, -O-, -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- or -C (CF ₃ ) _2- , more preferably single bond, -C (CH ₃ ) _2- or -C (CF ₃ ) _2- , particularly preferably a single bond or -C (CF ₃ ) _2- .

In a preferred embodiment of the present invention, Y in the polyimide resin is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, represented by the formula (26). Y is the formula within the above range in the polyimide resin (26), preferably ^{W 1} is a single bond, -C _{(CH 3) 2} - or -C _{(CF 3) 2} - a is the formula (26), more preferably When W ¹ is represented by the equation (26) which is a single bond or −C (CF ₃ ) _2−, it is easy to improve the curl resistance, elastic modulus and bending resistance of the optical film, and the YI value of the optical film can be increased. Easy to reduce. The ratio of the structural unit in which Y in the polyimide resin is represented by the formula (26) ^{can be measured using, for example, 1 1} H-NMR, or can be calculated from the charging ratio of the raw materials.

In a preferred embodiment of the present invention, at least a part of Y in the plurality of formulas (1) is the formula (5) :.

［式（５）中、Ｒ^１８〜Ｒ^２５は、互いに独立に、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基又は炭素数６〜１２のアリール基を表し、Ｒ^１８〜Ｒ^２５に含まれる水素原子は、互いに独立に、ハロゲン原子で置換されていてもよく、＊は結合手を表す］
及び／又は式（９）

[In formula (5), R ^{18 to} R ²⁵ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. The ^{hydrogen atoms contained in R 18 to} R ²⁵ may be substituted with halogen atoms independently of each other, and * represents a bond.]
And / or formula (9)

［式（９）中、Ｒ^３５〜Ｒ^４０は、互いに独立に、水素原子、炭素数１〜６のアルキル基又は炭素数６〜１２のアリール基を表し、Ｒ^３５〜Ｒ^４０に含まれる水素原子は、互いに独立に、ハロゲン原子で置換されていてもよく、＊は結合手を表す］
で表される。複数の式（１）中のＹの少なくとも一部が式（５）で表される、及び／又は、式（９）で表されると、光学フィルムの耐カール性、弾性率及び光学特性を向上させやすい。

[In the formula (9), R ^{35 to} R ⁴⁰ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and hydrogen contained in ^{R 35 to} R ^40. Atoms may be substituted with halogen atoms independently of each other, with * representing a bond]
It is represented by. When at least a part of Y in the plurality of formulas (1) is represented by the formula (5) and / or the formula (9), the curl resistance, elastic modulus and optical properties of the optical film are determined. Easy to improve.

In formula (5), R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ are independent of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and 1 carbon atom. Represents an alkoxy group of ~ 6 or an aryl group of 6-12 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, or the aryl group having 6 to 12 carbon atoms include the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms in the formula (3). Examples of the group or the aryl group having 6 to 12 carbon atoms can be mentioned above. R ^{18 to} R ²⁵ represent independently of each other, preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably an hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and here, R ^{18 to} R ^25. The hydrogen atoms contained in the above may be substituted with halogen atoms independently of each other. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. R ^{18 to} R ²⁵ are more preferable from the viewpoint of easily increasing the curl resistance, elastic coefficient and bending resistance of the optical film, and easily increasing the transparency and maintaining the transparency, independently of each other. Is a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and more preferably R ¹⁸ , R ¹⁹ , R ²⁰ and R ²³ , R ²⁴ and R ²⁵ are hydrogen atoms, R ²¹ and R ^22. Is a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and particularly preferably R ²¹ and R ²² are a methyl group or a trifluoromethyl group.

^{In the formula (9), R 35 to} R ⁴⁰ are described from the viewpoints of easily increasing the curl resistance, elastic coefficient and bending resistance of the optical film, and easily increasing the transparency and maintaining the transparency. It is preferably 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, and further preferably a hydrogen atom. Here, the ^{hydrogen atoms contained in R 35 to} R ⁴⁰ may be substituted with halogen atoms independently of each other, and examples of the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. .. Examples of the alkyl group having 1 to 6 carbon atoms and the aryl group having 6 to 12 carbon atoms in R ^{35 to} R ^{40 are exemplified above.}

In a preferred embodiment of the present invention, formula (5) is represented by formula (5'), and formula (9) is represented by formula (9') :.

で表される。すなわち、複数のＹの少なくとも一部は、式（５’）及び／又は式（９’）で表される。この場合、光学フィルムの耐カール性、弾性率及び耐屈曲性を高めやすい。さらに、式（５）が式（５’）で表される場合、フッ素元素を含有する骨格によりポリイミド系樹脂の溶媒への溶解性を高め、該樹脂を含有するワニスの保管安定性を向上しやすいと共に、該ワニスの粘度を低減しやすく、光学フィルムの加工性を向上しやすい。また、フッ素元素を含有する骨格により、光学フィルムの光学特性を向上しやすい。

It is represented by. That is, at least a part of the plurality of Y is represented by the formula (5') and / or the formula (9'). In this case, it is easy to improve the curl resistance, elastic modulus and bending resistance of the optical film. Further, when the formula (5) is represented by the formula (5'), the skeleton containing a fluorine element enhances the solubility of the polyimide resin in the solvent and improves the storage stability of the varnish containing the resin. In addition to being easy, it is easy to reduce the viscosity of the varnish and improve the processability of the optical film. Further, the skeleton containing a fluorine element makes it easy to improve the optical characteristics of the optical film.

In a preferred embodiment of the present invention, Y in the polyimide resin is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, according to the formula (5), particularly the formula (5). It is represented by'). When Y in the above range in the polyimide resin is represented by the formula (5), particularly the formula (5'), the skeleton containing a fluorine element enhances the solubility of the polyimide resin in the solvent and contains the resin. It is easy to reduce the viscosity of the varnish and improve the processability of the optical film. Further, the skeleton containing a fluorine element makes it easy to improve the optical characteristics of the optical film. It should be noted that preferably, 100 mol% or less of Y in the polyimide resin is represented by the formula (5), particularly the formula (5'). Y in the polyimide resin may be of the formula (5), particularly the formula (5'). The ratio of the structural units represented by the formula (5) of Y in the polyimide resin ^{can be measured using, for example, 1 1} H-NMR, or can be calculated from the charging ratio of the raw materials.

In a preferred embodiment of the present invention, the plurality of structural units represented by the formula (1) have a configuration in which Y is represented by the formula (9) in addition to the structural unit in which Y is represented by the formula (5). It is preferable to include more units. When Y further contains the structural unit represented by the formula (9), it is easy to further improve the curl resistance and elastic modulus of the optical film.

The polyimide-based resin may contain a structural unit represented by the formula (30) and / or a structural unit represented by the formula (31), and may also include the structural unit represented by the formula (1) and, in some cases, the formula (2). In addition to the structural unit represented by the formula (30), the structural unit represented by the formula (30) and / or the structural unit represented by the formula (31) may be included.

In the formula (30), Y ¹ is a tetravalent organic group, preferably an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with fluorine. Examples of Y ¹ include formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) and A group represented by the formula (29), a group in which the hydrogen atom in the groups represented by the formulas (20) to (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and a group. A chain hydrocarbon group having a tetravalent carbon number of 6 or less is exemplified. In one embodiment of the present invention, a polyimide resin may include a plurality of kinds of Y ^1, Y ¹ of the plurality of kinds may be the same as each other or may be different.

In the formula (31), Y ² is a trivalent organic group, preferably an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with fluorine. Examples of Y ² include the above equations (20), (21), (22), (23), (24), (25), (26), (27), and (28). ) And a group in which any one of the bonds of the group represented by the formula (29) is replaced with a hydrogen atom, and a chain hydrocarbon group having a trivalent carbon number of 6 or less are exemplified. In one embodiment of the present invention, a polyimide resin may include a plurality of kinds of Y ^2, Y ² a plurality of species may be the same as each other or may be different.

In formulas (30) and (31), X ¹ and X ² are divalent organic groups independently of each other, and preferably a hydrocarbon group in which a hydrogen atom in the organic group is substituted with a hydrocarbon group or fluorine. It is an organic group that may be substituted with. Examples of X ¹ and X ² include the above equations (10), (11), (12), (13), (14), (15), (16), (17) and A group represented by the formula (18); a group in which a hydrogen atom in the groups represented by the formulas (10) to (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; A chain hydrocarbon group having 6 or less carbon atoms is exemplified.

In one embodiment of the present invention, the polyimide resin is a structural unit represented by the formulas (1) and / or the formula (2), and optionally a configuration represented by the formulas (30) and / or the formula (31). It consists of units. Further, from the viewpoint of easily improving the optical characteristics, curl resistance, elastic modulus and bending resistance of the optical film, the ratio of the structural units represented by the formulas (1) and (2) in the polyimide resin is expressed by the formula. Based on (1) and the formula (2), and optionally all the structural units represented by the formulas (30) and (31), preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably. It is 95 mol% or more. In the polyimide resin, the proportions of the structural units represented by the formulas (1) and (2) are the formulas (1) and (2), and in some cases, the formulas (30) and / or the formula (31). It is usually 100% or less based on all the constituent units represented by. The above ratio can be measured using, for example, ^{1 1} H-NMR, or can be calculated from the raw material charging ratio.

In one embodiment of the present invention, the content of the polyimide resin and / or the polyamide resin in the optical film is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, based on 100 parts by mass of the optical film. It is more preferably 50 parts by mass or more, preferably 99.5 parts by mass or less, and more preferably 95 parts by mass or less. When the content of the polyimide resin and / or the polyamide resin is within the above range, the optical characteristics, curl resistance, and elastic modulus of the optical film can be easily improved.

The weight average molecular weight of the polyimide resin and the polyamide resin is preferably 200,000 or more, more preferably 230,000 or more in terms of standard polystyrene from the viewpoint of easily increasing the curl resistance, elastic modulus and bending resistance of the optical film. The above is even more preferably 250,000 or more, even more preferably 270,000 or more, and particularly preferably 280,000 or more. The weight average molecular weight of the polyimide resin and the polyamide resin is preferably 1,000,000 from the viewpoint that the solubility of the resin in a solvent is easily improved and the stretchability and processability of the optical film are easily improved. Below, it is more preferably 800,000 or less, still more preferably 700,000 or less, and particularly preferably 500,000 or less. The weight average molecular weight can be determined by, for example, gel permeation chromatography (hereinafter, may be referred to as GPC) and converted to standard polystyrene, and may be calculated by, for example, the method described in Examples.

In the polyamide-imide resin, the content of the structural unit represented by the formula (2) is preferably 0.1 mol or more, more preferably 0.5 mol, with respect to 1 mol of the structural unit represented by the formula (1). It is mol or more, more preferably 1.0 mol or more, particularly preferably 1.5 mol or more, preferably 6.0 mol or less, more preferably 5.0 mol or less, still more preferably 4.5 mol or less. .. When the content of the structural unit represented by the formula (2) is at least the above lower limit, the curl resistance and elastic modulus of the optical film can be easily increased. Further, when the content of the structural unit represented by the formula (2) is not more than the above upper limit, the thickening due to the hydrogen bond between the amide bonds in the formula (2) is suppressed and the processability of the optical film is improved. Easy to make.

In a preferred embodiment of the present invention, the polyimide resin and / or the polyamide resin contained in the optical film may contain a halogen atom such as a fluorine atom which can be introduced by, for example, the above-mentioned fluorine-containing substituent or the like. .. When the polyimide resin and / or the polyamide resin contains a halogen atom, it is easy to improve the elastic modulus of the optical film and reduce the YI value. When the elastic modulus of the optical film is high, it is easy to suppress the occurrence of scratches and wrinkles. Further, when the YI value of the optical film is low, it becomes easy to improve the transparency and visibility of the film. The halogen atom is preferably a fluorine atom. Preferred fluorine-containing substituents for containing a fluorine atom in the polyimide resin include, for example, a fluoro group and a trifluoromethyl group.

The content of halogen atoms in the polyimide resin and the polyamide resin is preferably 1 to 40% by mass, more preferably 5 to 40% by mass, still more preferably 5 to 40% by mass, based on the mass of the polyimide resin and the polyamide resin, respectively. It is 5 to 30% by mass. When the content of the halogen atom is at least the above lower limit, the elastic modulus of the optical film is further improved, the water absorption rate is lowered, the YI value is further reduced, and the transparency and visibility are more likely to be improved. When the content of halogen atoms is not more than the above upper limit, synthesis becomes easy.

The imidization ratio of the polyimide resin and the polyamide-imide resin is preferably 90% or more, more preferably 93% or more, still more preferably 96% or more. From the viewpoint of easily improving the optical characteristics of the optical film, the imidization ratio is preferably at least the above lower limit. The upper limit of the imidization rate is 100% or less. The imidization ratio indicates the ratio of the molar amount of the imide bond in the polyimide resin to twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide resin. When the polyimide resin contains a tricarboxylic acid compound, the value is twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimide resin, and the molar amount of the structural unit derived from the tricarboxylic acid compound. The ratio of the molar amount of the imide bond in the polyimide resin to the total of the above is shown. The imidization rate can be determined by an IR method, an NMR method, or the like.

Commercially available products may be used as the polyimide resin and the polyamide resin. Examples of commercially available polyimide resins include Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Ltd., KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd., and the like.

In the present invention, the optical film may contain a polyamide resin. The polyamide-based resin according to this embodiment is a polymer mainly composed of a repeating structural unit represented by the formula (2). Preferred examples and specific examples of Z in the formula (2) in the polyamide-based resin are the same as preferable examples and specific examples of Z in the polyimide-based resin. The polyamide-based resin may contain two or more types of repeating structural units represented by the formula (2) having different Z's.

(Resin manufacturing method)
The polyimide resin and the polyimide precursor resin can be produced, for example, using a tetracarboxylic acid compound and a diamine compound as main raw materials, and the polyamide-imide resin and the polyamide-imide precursor resin can be produced, for example, by a tetracarboxylic acid compound, a dicarboxylic acid compound and a diamine compound. Can be produced as a main raw material, and the polyamide resin can be produced, for example, using a diamine compound and a dicarboxylic acid compound as main raw materials. Here, the dicarboxylic acid compound preferably contains at least a compound represented by the formula (3 ").

［式（３”）中、Ｒ^１〜Ｒ^８は、互いに独立に、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、又は炭素数６〜１２のアリール基を表し、Ｒ^１〜Ｒ^８に含まれる水素原子は、互いに独立に、ハロゲン原子で置換されていてもよく、
Ａは、単結合、−Ｏ−、−ＣＨ_２−、−ＣＨ_２−ＣＨ_２−、−ＣＨ（ＣＨ_３）−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−Ｓ−、−ＣＯ−又は−Ｎ（Ｒ^９）−を表し、
Ｒ^９は水素原子、ハロゲン原子で置換されていてもよい炭素数１〜１２の１価の炭化水素基を表し、
ｍは０〜４の整数であり、
Ｒ^３１及びＲ^３２は、互いに独立に、ヒドロキシル基、メトキシ基、エトキシ基、ｎ−プロポキシ基、イソプロポキシ基、ｎ−ブトキシ基、イソブトキシ基、ｓｅｃ−ブトキシ基、ｔｅｒｔ−ブトキシ基又は塩素原子を表す。］

[In the formula (3 ″), R ^{1 to} R ⁸ independently contain a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Represented, the ^{hydrogen atoms contained in R 1 to} R ⁸ may be substituted with halogen atoms independently of each other.
A represents a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, - C (CF 3) 2 -, - Represents SO _2- , -S-, -CO- or -N (R ⁹ )-
R ⁹ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a hydrogen atom or a halogen atom.
m is an integer from 0 to 4
R ³¹ and R ³² independently contain a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group or a chlorine atom. show. ]

In a preferred embodiment of the present invention, the dicarboxylic acid compound is a compound represented by the formula (3 ") in which m is 0. The dicarboxylic acid compound is represented by the formula (3") in which m is 0. It is more preferable to use a compound represented by the formula (3 ″) in which A is an oxygen atom in addition to the compound to be used. In another preferred embodiment, the dicarboxylic acid compound is R ³¹ and It is a compound represented by the formula (3 ″) in which R ^{32 is a chlorine atom.} Further, a diisocyanate compound may be used instead of the diamine compound.

Examples of the diamine compound used in the production of the resin include aliphatic diamines, aromatic diamines and mixtures thereof. In addition, in this embodiment, "aromatic diamine" represents a diamine in which an amino group is directly bonded to an aromatic ring, and an aliphatic group or other substituent may be contained in a part of the structure. The aromatic ring may be a monocyclic ring or a condensed ring, and examples thereof include, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring. Among these, a benzene ring is preferably exemplified. Further, the "aliphatic diamine" represents a diamine in which an amino group is directly bonded to an aliphatic group, and an aromatic ring or other substituent may be contained as a part of the structure thereof.

Examples of the aliphatic diamine include acyclic aliphatic diamines such as hexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, norbornandiamine and 4,4'. − Examples thereof include cyclic aliphatic diamines such as diaminodicyclohexylmethane. These can be used alone or in combination of two or more.

Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylene diamine, p-xylylene diamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene and the like. , 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4) -Aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] Propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (with TFMB) (May be described), 4,4'-bis (4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene , 9,9-bis (4-amino-3-chlorophenyl) fluorene, 9,9-bis (4-amino-3-fluorophenyl) fluorene, and other aromatic diamines having two or more aromatic rings. These can be used alone or in combination of two or more.

The aromatic diamines are preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3 , 3'-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2'-dimethylbenzidine, TFMB, 4,4'- Bis (4-aminophenoxy) biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 1, 4-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethylbenzidine , TFMB, 4,4'-bis (4-aminophenoxy) biphenyl. These can be used alone or in combination of two or more.

Among the above diamine compounds, one or more selected from the group consisting of aromatic diamines having a biphenyl structure are selected from the viewpoints of high elastic modulus, high transparency, high flexibility, high bending resistance and low coloring property of the optical film. It is preferable to use it. It is more preferable to use one or more selected from the group consisting of 2,2'-dimethylbenzidine, TFMB, 4,4'-bis (4-aminophenoxy) biphenyl and 4,4'-diaminodiphenyl ether, and TFMB is used. Is even more preferable.

Examples of the tetracarboxylic acid compound used in the production of the resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride; and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. Be done. The tetracarboxylic acid compound may be used alone or in combination of two or more. The tetracarboxylic dian compound may be a tetracarboxylic dian compound analog such as an acid chloride compound in addition to the dianhydride.

Specific examples of the aromatic tetracarboxylic dianhydride include a non-condensed polycyclic aromatic tetracarboxylic dianhydride, a monocyclic aromatic tetracarboxylic dianhydride, and a condensed polycyclic aromatic tetra. Examples include carboxylic dianhydride. Examples of the non-condensation polycyclic aromatic tetracarboxylic acid dianhydride include 4,4'-oxydiphthalic acid dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, and 2,2. ', 3,3'-benzophenone tetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (sometimes referred to as BPDA), 2,2', 3,3 '-Biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2, 2-Bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'-(hexafluoroisopropyridene) diphthalic acid Dianhydride (sometimes referred to as 6FDA), 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride , 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) methane Dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, 4,4'-(p-phenylenedioxy) diphthalic acid dianhydride, 4,4'-(m-phenylenedioxy) diphthalide Acid dianhydride can be mentioned. Examples of the monocyclic aromatic tetracarboxylic dianhydride include 1,2,4,5-benzenetetracarboxylic dianhydride, and the condensed polycyclic aromatic tetracarboxylic dianhydride. Examples thereof include 2,3,6,7-naphthalenetetracarboxylic dianhydride.

Among these, preferably 4,4'-oxydiphthalic acid dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride. Ethylene, BPDA, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis (3, 4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 6FDA, 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-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-di) Examples thereof include carboxyphenyl) methane dianhydride, 4,4'-(p-phenylenedioxy) diphthalic acid dianhydride and 4,4'-(m-phenylenedioxy) diphthalic acid dianhydride, more preferably. 4,4'-oxydiphthalic acid dianhydride, BPDA, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 6FDA, bis (3,4-dicarboxyphenyl) methane dianhydride and 4, Examples thereof include 4'-(p-phenylenedioxy) diphthalic acid dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or acyclic aliphatic tetracarboxylic dianhydride. The cyclic aliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride. Cycloalkanetetracarboxylic dianhydride such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, bicyclo [2.2] .2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3', 4,4'-tetracarboxylic dianhydride and their positional isomers are listed. Be done. These can be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride and the like. These can be used alone or in combination of two or more. Further, a cyclic aliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride may be used in combination.

Among the above tetracarboxylic dianhydrides, 4,4'from the viewpoints of high curl resistance, high elasticity, high surface hardness, high transparency, high flexibility, high bending resistance, and low coloring property of the optical film. -Oxydiphthalic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, BPDA, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-Diphenylsulfonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propanedianhydride, 6FDA, and mixtures thereof are preferred, BPDA and 6FDA, and mixtures thereof. Is more preferable, and 6FDA and BPDA are further preferable.

As the dicarboxylic acid compound used in the production of the resin, terephthalic acid, isophthalic acid, 4,4'-oxybis benzoic acid or an acid chloride compound thereof is preferably used. In addition to terephthalic acid, isophthalic acid, 4,4'-oxybis benzoic acid or their acid chloride compounds, other dicarboxylic acid compounds may be used. Examples of other dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, acid chloride compounds related thereto, acid anhydrides, and the like, and two or more of them may be used in combination. Specific examples include a dicarboxylic acid compound of isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; a chain hydrocarbon having 8 or less carbon atoms, and two benzoic acids. Examples thereof include compounds in which is single-bonded, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- or phenylene groups, and their acid chloride compounds. As a specific example, 4,4'-oxybis (benzoyl chloride), terephthaloyl chloride or isophthaloyl chloride are preferable, and 4,4'-oxybis (benzoyl chloride) and terephthaloyl chloride may be used in combination. More preferred.

The polyimide resin is obtained by further reacting tetracarboxylic acid and tricarboxylic acid and their anhydrides and derivatives in addition to the tetracarboxylic acid compound as long as the various physical properties of the optical film are not impaired. May be good.

Examples of the tetracarboxylic acid include a water adduct of the anhydride of the tetracarboxylic acid compound.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, acid chloride compounds related thereto, acid anhydrides, and the like, and two or more of them may be used in combination. Specific examples include an anhydride of 1,2,4-benzenetricarboxylic acid; an anhydride of 1,3,5-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic acid. A compound in which an anhydride and benzoic acid are single-bonded, -O-, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- or a phenylene group is linked. Can be mentioned.

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

In the production of the resin, the reaction temperature of the diamine compound, the tetracarboxylic acid compound and the dicarboxylic acid compound is not particularly limited, but is, for example, 5 to 350 ° C., preferably 20 to 200 ° C., and more preferably 25 to 100 ° C. The reaction time is also not particularly limited, but is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be carried out under conditions of an inert atmosphere or reduced pressure. In a preferred embodiment, the reaction is carried out under normal pressure and / or an atmosphere of an inert gas with stirring. 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, and for example, water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, etc. Alcohol-based solvents such as 2-butoxyethanol and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone (hereinafter sometimes referred to as GBL), γ-valerolactone, propylene glycol methyl Ester solvents such as ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; ethylcyclohexane and the like. Alicyclic hydrocarbon solvent; aromatic hydrocarbon solvent such as toluene and xylene; nitrile solvent such as acetonitrile; ether solvent such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvent such as chloroform and chlorobenzene; N, N-dimethyl Amid-based solvents such as acetoamide (hereinafter, may be referred to as DMAc) and N, N-dimethylformamide (hereinafter, may be referred to as DMF); sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide, and sulfolane; Examples thereof include carbonate solvents such as ethylene carbonate and propylene carbonate; and combinations thereof (mixed solvents). Among these, an amide-based solvent can be preferably used from the viewpoint of solubility.

In the imidization step in the production of the polyimide resin, imidization can be performed in the presence of an imidization catalyst. Examples of imidization catalysts include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidin, N-propylpiperidin, N-butylpyrrolidin, N-butylpiperidin, and N-propylhexahydro. Alicyclic amines such as azepine (monocyclic); azabicyclo [2.2.1] heptane, azabicyclo [3.2.1] octane, azabicyclo [2.2.2] octane, and azabicyclo [3.2. 2] Alicyclic amines such as nonane (polycyclic); and pyridine, 2-methylpyridine (2-picolin), 3-methylpyridine (3-picolin), 4-methylpyridine (4-picolin), 2- Ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine, 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and Examples include aromatic amines such as isoquinolin. Further, from the viewpoint of easily accelerating the imidization reaction, it is preferable to use an acid anhydride together with the imidization catalyst. Examples of the acid anhydride include conventional acid anhydrides used in the imidization reaction, and specific examples thereof include acetic anhydride, propionic anhydride, butyric anhydride and other aliphatic acid anhydrides, and phthalic acid and other aromatics. Acid anhydride and the like can be mentioned.

Polyimide-based resins and polyamide-based resins are separated and purified by conventional methods, for example, separation means such as filtration, concentration, extraction, crystallization, recrystallization, and column chromatography, or separation means combining these. Also, in a preferred embodiment, it can be isolated by adding a large amount of alcohol such as methanol to the reaction solution containing the transparent polyamideimide resin, precipitating the resin, and performing concentration, filtration, drying and the like.

(Optical film)
In the present invention, the content of the polyimide resin and / or the polyamide resin in the resin composition constituting the optical film is preferably 40% by mass or more, more preferably 50% by mass, based on the solid content of the resin composition. As mentioned above, it is more preferably 60% by mass or more, particularly preferably 70% by mass or more, and may be 100% by mass. When the content of the polyimide resin and / or the polyamide resin is at least the above lower limit value, the flexibility of the optical film is good. The solid content refers to the total amount of the components excluding the solvent from the resin composition.

In the present invention, the resin composition forming the optical film may further contain an inorganic material such as inorganic particles in addition to the above-mentioned polyimide-based resin and / or polyamide-based resin. Examples of the inorganic material include inorganic particles such as silica particles, titanium particles, aluminum hydroxide, zirconia particles, and barium titanate particles, and silicon compounds such as quaternary alkoxysilane such as tetraethyl orthosilicate. From the viewpoint of the stability of the varnish and the dispersibility of the inorganic material, silica particles, aluminum hydroxide, and zirconia particles are preferable, and silica particles are more preferable.

The average primary particle size of the inorganic material particles is preferably 1 to 100 nm, more preferably 5 to 70 nm, still more preferably 10 to 50 nm, and particularly preferably 10 to 30 nm. When the average primary particle size of the silica particles is in the above range, the transparency tends to be improved, and the cohesive force of the silica particles is weakened, so that the silica particles tend to be easy to handle.

In the present invention, the silica particles may be a silica sol in which the silica particles are dispersed in an organic solvent or the like, or a silica fine particle powder produced by the vapor phase method, but the liquid is preferable because it is easy to handle. It is a silica sol produced by the phase method.

The average primary particle size of the silica particles in the optical film can be determined by observation with a transmission electron microscope (TEM). The average primary particle size of the silica particles before forming the optical film can be obtained by the BET method, and the particle size distribution can be obtained by a commercially available laser diffraction type particle size distribution meter.

In the present invention, when the resin composition contains an inorganic material, the content thereof is preferably 0.001% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 60, based on the solid content of the resin composition. It is mass% or less, more preferably 15% by mass or more and 40% by mass or less. When the content of the inorganic material in the resin composition is within the above range, the transparency and mechanical strength of the optical film tend to be compatible with each other. The solid content refers to the total amount of the components excluding the solvent from the resin composition.

The resin composition constituting the optical film may further contain other components in addition to the components described above. Other components include, for example, UV absorbers, antioxidants, mold release agents, light stabilizers, brewing agents, flame retardants, lubricants and leveling agents.

The ultraviolet absorber can be appropriately selected from those usually used as an ultraviolet absorber in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light having a wavelength of 400 nm or less. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone compounds, salicylate compounds, benzotriazole compounds, and triazine compounds. The UV absorber can be used alone or in combination of two or more. Since the optical film contains an ultraviolet absorber, deterioration of the resin is suppressed, so that visibility can be improved when the obtained optical film is applied to an image display device or the like. As used herein, the term "system compound" refers to a derivative of a compound to which the "system compound" is attached. For example, the "benzophenone-based compound" refers to a compound having benzophenone as a maternal skeleton and a substituent attached to benzophenone.

When the optical film contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more with respect to 100 parts by mass of the optical film. It is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 6 parts by mass or less. The suitable content varies depending on the UV absorber used, but if the content of the UV absorber is adjusted so that the light transmittance at 400 nm is about 20 to 60%, the light resistance of the optical film is enhanced and the transparency is improved. Easy to increase.

In the present invention, when the resin composition contains a resin component such as a polyimide resin, an inorganic material, and other components other than the ultraviolet absorber, the content of the other components is preferably 0 with respect to the total mass of the optical film. It is 001% or more and 20% by mass or less, more preferably 0.01% or more and 10% by mass or less.

In the present invention, the optical film is, for example, a reaction solution of a polyimide resin and / or a polyamide resin obtained by selecting and reacting with the tetracarboxylic acid compound, the diamine and the other raw materials, if necessary. It can be produced from a resin varnish prepared by adding a solvent to a resin composition containing an inorganic material and other components, mixing and stirring. In the resin composition, a solution of the purchased polyimide resin or the like or a solution of the purchased solid polyimide resin or the like may be used instead of the reaction solution of the polyimide resin or the like.

As the solvent used for preparing the resin varnish, a solvent capable of dissolving or dispersing a resin component such as a polyimide resin can be appropriately selected. From the viewpoint of solubility, coatability, drying property and the like of the resin component, the boiling point of the organic solvent is preferably 120 to 300 ° C, more preferably 120 to 270 ° C, still more preferably 120 to 250 ° C, and particularly preferably 120. ~ 230 ° C. Specific examples of such an organic solvent include amide solvents such as DMF, DMAc and N-methylpyrrolidone; lactone solvents such as GBL and γ-valerolactone; and ketone solvents such as cyclohexanone, cyclopentanone and methyl ethyl ketone. Solvents: Acetate-based solvents such as butyl acetate and amyl acetate; sulfur-containing solvents such as dimethyl sulfoxide, dimethyl sulfoxide and sulfolane, and carbonate-based solvents such as ethylene carbonate and propylene carbonate can be mentioned. Among them, DMAc (boiling point: 165 ° C.), GBL (boiling point: 204 ° C.), N-methylpyrrolidone (boiling point: 202 ° C.), butyl acetate (boiling point: 126 ° C.) because of its excellent solubility in polyimide-based resin and polyamide-based resin. ° C.), cyclopentanone (boiling point: 131 ° C.) and amyl acetate (boiling point: 149 ° C.) are preferred solvents selected from the group. As the solvent, one type may be used alone, or two or more types may be used in combination. When two or more kinds of solvents are used, it is preferable to select the type of solvent so that the boiling point of the solvent having the highest boiling point among the solvents used falls within the above range.

The amount of the solvent may be selected so as to have a viscosity that allows the resin varnish to be handled, and is not particularly limited. For example, the amount of the solvent is preferably 50 to 95 parts by mass with respect to 100 parts by mass of the solid content of the resin composition. It is preferably 70 to 95 parts by mass, and more preferably 80 to 95 parts by mass.

The thickness of the optical film may be appropriately determined depending on the intended use of the optical film and the like, but is usually 10 to 500 μm, preferably 15 to 200 μm, and more preferably 20 to 130 μm. When the thickness of the optical film is within the above range, the flexibility and curl resistance of the optical film tend to be good.

<Curing resin layer>
The laminated film of the present invention has an optical film and a cured resin layer laminated on one side of the optical film. The cured resin layer can be provided on the optical film by, for example, irradiating the cured resin composition coated on the optical film with active energy rays to cure the resin by polymerization, cross-linking, or other curing reaction. Further, in the present invention, the cured resin layer is preferably a layer having a function, and in the present specification, the "function" means a function imparted to the optical film, and more specifically, it is hard. Coat function, antistatic function, antiglare function, low reflection function, antireflection function, antifouling function, gas barrier function, primer function, electromagnetic wave shielding function, undercoat function, ultraviolet absorption function, adhesive function, hue adjustment function, etc. However, it is not limited to these. Further, in the present specification, "curing" means that the resin layer does not easily peel off from the optical film so as to retain the function imparted to the optical film as well as polymerization, cross-linking, and other curing reactions. means. The resin layer having a function (also referred to as a functional layer) may be a layer having one kind of function, or may be a layer having two or more kinds of functions. From the viewpoint of being easy to use as a front plate of a flexible display device, at least one of the functional layers is selected from the group consisting of a hard coat function, an antistatic function, an antiglare function, a low reflection function, an antireflection function and an antifouling function. It is preferable that the layer has at least one function. As the functional layer, one layer may have a plurality of functions, or two or more layers having each function may be laminated. When two or more layers are laminated, the order of lamination is appropriately set according to the function. These layers are laminated on one or both sides of the optical film. When laminated on both sides, the thickness, function, and stacking order of the layers laminated on each surface may be the same or different. The functional layer is preferably 5 layers or less, more preferably 3 layers or less, still more preferably 2 layers or less, and particularly preferably 1 layer, from the viewpoint of easily preventing curling of the laminated film.

The thickness of the functional layer may be appropriately set according to the desired function, but is preferably 30 μm or less from the viewpoint of easily preventing curling of the laminated film and easily increasing weight reduction and optical homogeneity. It is more preferably 20 μm or less, still more preferably 1 μm or more and 10 μm or less, still more preferably 1 μm or more and 8 μm or less, and particularly preferably 2 μm or more and 7 μm or less. When two or more functional layers are laminated, the thickness referred to here means the thickness of all the layers. In the present invention, the thickness of the functional layer can be calculated from the difference from the thickness of the optical film by using, for example, a contact type digital indicator.

When the thickness of the optical film is T1 and the thickness of the functional layer is T2, T1 / T2 is preferably 1 or more and 40 or less, more preferably 1.5 or more and 30 or less, still more preferably 2 or more and 20 or less, especially. It is preferably 3 or more and 10 or less. When T1 / T2 is in the above range, the optical film and the functional layer are balanced, and curling is less likely to occur.

It is preferable that the optical film and the functional layer are in close contact with each other. Adhesion can be evaluated by, for example, a crosshatch test based on JIS K 5600-5-6. Specifically, scratches are made on a 10 × 10 substrate at 2 mm intervals, and cellophane tape (registered trademark, Nichiban Co., Ltd.) The number of base stitches remaining after the cellophane tape is peeled off in the direction of 60 ° with respect to the surface is counted. At this time, it can be said that the larger the number of remaining grids, the higher the adhesion, and the number is preferably 100.

(Hard coat function)
The hard coat function is a function of imparting scratch resistance, chemical resistance, and the like to the surface of the optical film to protect the optical film. In the laminated film of the present invention, the functional layer may be a layer having a hard coat function, for example, a hard coat layer. As the hard coat layer, a known hard coat layer may be appropriately adopted, and examples thereof include known hard coat layers such as acrylic type, epoxy type, urethane type, benzyl chloride type, and vinyl type. Among these, an acrylic-based, urethane-based, or a combination thereof hard coat layer is preferable from the viewpoint of suppressing a decrease in visibility of the laminated film in the wide-angle direction and improving bending resistance. For example, the hard coat layer may be a cured product of a composition containing an active energy ray-curable compound. The active energy ray-curable compound is a compound having a property of being cured by irradiating with an active energy ray such as an electron beam or ultraviolet rays. Examples of such an active energy ray-curable compound include an electron beam-curable compound that is cured by irradiating an electron beam and an ultraviolet-curable compound that is cured by irradiating an ultraviolet ray. These compounds are the same compounds as the main components of the hard coat agent used for forming a normal hard coat layer, and examples thereof include (meth) acrylic resins. Among the (meth) acrylic resins, those containing a polyfunctional (meth) acrylate compound as a main component are preferable. In addition, in this specification, (meth) acrylic means acrylic and / or methacrylic, and (meth) acrylate means acrylate and / or methacrylate.

The polyfunctional (meth) acrylate-based compound is a compound having at least two acryloyloxy groups and / or methacryloyloxy groups in the molecule, and specifically, ethylene glycol di (meth) acrylate and diethylene glycol di (meth). ) Acryloyl, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropanthry (meth) acrylate, trimethylol ethanetri (meth) acrylate, tetramethylol methanetri (meth) acrylate , Tetramethylolmethanetetra (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerintri (meth) acrylate, dipentaerythritol tri (meth) acrylate, Dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris ((meth) acryloyloxyethyl) isocyanurate, (meth) acryloyloxy on the phosphazene ring of the phosphazenic compound. Obtained by reacting a phosphazenic acrylate compound or a phosphazene-based methacrylate compound into which a group has been introduced, a polyisocyanate having at least two isocyanate groups in the molecule, and a polyol compound having at least one (meth) acryloyloxy group and a hydroxyl group. Urethane (meth) acrylate compound, polyester (meth) acrylate compound obtained by reaction of at least two carboxylic acid halides in the molecule with a polyol compound having at least one (meth) acryloyloxy group and a hydroxyl group, and Examples thereof include oligomers such as dimer and trimeric of each of the above compounds.

These compounds may be used alone or in admixture of two or more. In addition to the above polyfunctional (meth) acrylate compound, at least one monofunctional (meth) acrylate may be used. Examples of the monofunctional (meth) acrylate include hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl. Examples thereof include (meth) acrylate and glycidyl (meth) acrylate. These compounds are used alone or in admixture of two or more. The content of the monofunctional (meth) acrylate-based compound is preferably 10% by mass or less with respect to the solid content of the compound contained in the composition for forming a functional layer, for example, a coating material for a hard coat layer. In addition, in this specification, a solid content means all components except a solvent contained in a curable composition.

A polymerizable oligomer may be added to the functional layer, for example, for the purpose of adjusting the hardness. Examples of such oligomers include terminal (meth) acrylate polymethyl methacrylate, terminal styryl poly (meth) acrylate, terminal (meth) acrylate polystyrene, terminal (meth) acrylate polyethylene glycol, terminal (meth) acrylate acrylonitrile-styrene copolymer, and the like. Macromonomers such as terminal (meth) acrylate styrene-methyl (meth) acrylate copolymers can be mentioned. When the polymerizable oligomer is added, its content is preferably 5 to 50% by mass with respect to the solid content of the composition for forming a functional layer.

The active energy ray-curable compound may be used in the state of a solution mixed with a solvent. The active energy ray-curable compound and a solution thereof may be commercially available as a hard coat agent. Specific examples of commercially available hard coat agents include NK Hard M101 (manufactured by Shin-Nakamura Chemical Co., Ltd., urethane acrylate compound) and NK ester A-TMM-3L (manufactured by Shin-Nakamura Chemical Co., Ltd., tetramethylol methanetri). Acrylate), NK ester A-9530 (manufactured by Shin-Nakamura Chemical Co., Ltd., dipentaerythritol hexaacrylate), KAYARAD (registered trademark) DPCA series (manufactured by Nippon Kayaku Co., Ltd., derivative of dipentaerythritol hexaacrylate compound), Aronix (registered trademark) M-8560 (Toa Synthetic Co., Ltd., polyester acrylate compound), New Frontier (registered trademark) TEICA (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., tris (acryloyloxyethyl) isocyanurate), PPZ ( Kyoeisha Chemical Co., Ltd., phosphazenic methacrylate compound) and the like are exemplified.

As a method of laminating the hard coat layer on the optical film, for example, a composition for forming a hard coat layer containing an active energy ray-curable compound or an active energy ray-curable resin is applied to the surface of the optical film, and the active energy rays are applied. You just have to irradiate. Such a composition can be obtained by mixing an active energy ray-curable compound with an additive or the like, if necessary. The cured product of the composition for forming the hard coat layer constitutes the hard coat layer.

The composition for forming a hard coat layer preferably contains a solvent, and it is preferable that the active energy ray-curable compound is diluted with a solvent in the composition for forming a hard coat layer. In this case, the composition is produced by mixing an active energy ray-curable compound with various additives for imparting surface smoothness, for example, silicone oil, and then diluting the obtained mixture with a solvent. Alternatively, the active energy ray-curable compound may be diluted with a solvent and then mixed with an additive to be produced, or the active energy ray-curable compound and an additive diluted with a solvent in advance may be mixed and produced. Alternatively, it may be produced by mixing an active energy ray-curable compound diluted with a solvent in advance and an additive diluted with a solvent in advance. The mixed composition may be further stirred.

From the viewpoint of facilitating coating, it is preferable that the composition for forming a hard coat layer contains an appropriate solvent. Solvents include aliphatic hydrocarbons such as hexane and octane, aromatic hydrocarbons such as toluene and xylene, alcohols such as ethanol, 1-propanol, isopropanol and 1-butanol, and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Esters such as ethyl acetate and butyl acetate, cellosolves and the like can be appropriately selected and used. Several kinds of these organic solvents may be mixed and used as needed. The boiling point of the solvent is preferably in the range of 70 to 200 ° C. from the viewpoint that the composition for forming a hard coat layer is heated after coating to easily evaporate the organic solvent. The type and amount of the solvent are appropriately selected according to the type and amount of the active energy ray-curable compound used, the material and shape of the base material, for example, the optical film, the coating method, and the thickness of the target hard coat layer. Will be done.
The heating temperature for drying the composition for forming a hard coat layer after coating is preferably ± 30 ° C., more preferably ± 20 ° C., with respect to the boiling point of the solvent contained in the composition. When the drying temperature of the composition for forming the hard coat layer is in the above range, the solvent is unlikely to remain in the hard coat layer from which the solvent is obtained, and the adhesiveness tends to be difficult to decrease.
The solid content of the composition for forming a hard coat layer is preferably 5 to 60% by mass, more preferably 10 to 55% by mass, still more preferably 20 to 50% by mass, and particularly preferably 25 to 50% by mass. When the solid content is in the above range, the coating thickness is not too thick and the curl prevention effect tends to be good, and the smoothness of the surface of the obtained hard coat layer tends to be good.

The composition for forming a hard coat layer may contain a polymerization initiator. When ultraviolet rays or visible light are used as the active energy rays, a photopolymerization initiator is usually used as the polymerization initiator.

Examples of the photopolymerization initiator include acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl-2-hydroxy-2-methylpropan-1-one, carbazole, xanthone, 4-chlorobenzophenone, 4, 4'-diaminobenzophenone, 1,1-dimethoxydeoxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1- (4-dodecylphenyl) -2- Hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morphorinopropane-1-one, triphenylamine, 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene, benzaldehyde, benzoin ethyl ether, benzoisopropyl ether, benzophenone, Michler ketone, 3-methylacetophenone, 3,3', 4,4'-tetra-tert-butylperoxycarbonylbenzophenylone (sometimes referred to as BTTB), 2- (dimethylamino) -1- [4- (morpholinyl) phenyl] -2 -Phenylmethyl) -1-butanone, 4-benzoyl-4'-methyldiphenylsulfide, benzyl and the like can be mentioned. Moreover, the photopolymerization initiator may be used in combination with a dye sensitizer. Examples of the pigment sensitizer include xanthene, thioxanthene, coumarin, ketocoumarin and the like. Examples of the combination of the photopolymerization initiator and the dye sensitizer include a combination of BTTB and xanthene, a combination of BTTB and thioxanthene, a combination of BTTB and coumarin, and a combination of BTTB and ketocoumarin.

When a photopolymerization initiator is used, the amount used is preferably 0.1 part by mass or more with respect to 100 parts by mass of the active energy ray-curable compound. When the amount used is in the above range, it tends to be easy to obtain a sufficient curing rate. The amount of the photopolymerization initiator used is preferably 10 parts by mass or less per 100 parts by mass of the active energy ray-curable compound.

The composition for forming a hard coat layer may contain an antistatic agent in addition to the active energy ray-curable compound. When the composition contains an antistatic agent, an antistatic function can be imparted to the hard coat layer. Examples of the antistatic agent include surfactants, conductive polymers, conductive particles, alkali metal salts and / or organic cation-anionic salts. These antistatic agents are used alone or in admixture of two or more.

Examples of the surfactant include hydrocarbon-based surfactants, fluorine-based surfactants, silicone-based surfactants, and the like.

Examples of the conductive polymer include polyaniline, polypyrrole, polyacetylene, polythiophene and the like.

Examples of the conductive particles include particles such as indium-tin-composite oxide (ITO) and antimony-doped tin oxide.

Examples of the alkali metal salt include organic salts and inorganic salts of alkali metals. Examples of the alkali metal ion constituting the cation part of the alkali metal salt include lithium, sodium, and potassium ions. Among these alkali metal ions, lithium ions are preferable.

The anion portion of the alkali metal salt may be composed of an organic substance or an inorganic substance. Examples of the anion portion constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , C ₄ F ₉ SO ₃ ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ , (FSO ₂ ) ₂ N ⁻ , ⁻ O ₃ S (CF ₂ ) ₃ SO ₃ ⁻ , CO ₃ ^2- , Equation (A1) ~ formula _{(A4), (A1) :(} C n F 2n + 1 SO 2) 2 n - represents the (n is an integer of from 1 to _{10), (A2): CF 2} (C m F 2m SO 2) ₂ N ^- (m represents an integer of _{^{1~10), (A3): -}} O 3 S (CF 2) l SO 3 - (l represents an integer of _{1~10), (A4) :( C} p An anion portion or the like represented by F _{2p + 1} SO ₂ ) N ⁻ (C _q F _{2q + 1} SO ₂ ), (where p and q represent integers of 1 to 10 independently of each other) is used. Among them, the anion portion containing a fluorine atom is preferably used because an ionic compound having good ionic dissociation property can be obtained. The anion portions constituting the inorganic salt include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , and SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ^{− and the} like are used. As the anion part, (FSO ₂ ) ₂ N ⁻ , (CF ₃ O ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ are preferable, and (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO _2). ) ₂ N ⁻ is more preferable.

The organic cation-anion salt is an organic salt in which the cation portion is composed of a cation portion and an anion portion, and the cation portion is an organic substance. The anion portion may be an organic substance or an inorganic substance. The "organic cation-anionic salt" may be a substance referred to as an ionic liquid or an ionic solid.

Specifically, as the cation component, a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrrolin skeleton, a cation having a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, Examples thereof include pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation and the like. Examples of the anion component include the same as the anion portion of the alkali metal salt. Among them, the anionic component containing a fluorine atom is preferably used because an ionic compound having good ionic dissociation property can be obtained.

The composition for forming a hard coat layer is an organic compound containing, for example, a bromine atom, a fluorine atom, a sulfur atom, a benzene ring, and an inorganic oxide such as tin oxide, antimony oxide, titanium oxide, zirconium oxide, zinc oxide, and silicon oxide. It may contain fine particles and the like. In this case, the refractive index of the obtained hard coat layer can be adjusted, and the hard coat layer can be provided with optical functions such as a low reflection function and an antireflection function.

A layer containing an active energy ray-curable compound can be formed by applying a composition for forming a hard coat layer containing an active energy ray-curable compound onto an optical film and then drying the composition. The coating can be carried out by a usual method such as a microgravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a cast transfer method, a flow coating method, or a spray coating method. From the viewpoint of easily increasing the optical homogeneity of the laminated film, it is preferable to laminate the composition for forming a hard coat layer by a microgravure coating method or a die coating method.

Then, by irradiating with active energy rays, the active energy ray-curable compound coated on the surface of the optical film is cured, and a target hard coat layer is obtained. Examples of the active energy ray include an electron beam, ultraviolet rays, visible light, and the like, and are appropriately selected according to the type of the active energy ray-curable compound used. The active energy rays may be irradiated in the same manner as in the formation of a normal hard coat layer. The intensity of the active energy ray to be irradiated, the irradiation time, and the like are appropriately selected according to the type of the curable compound to be used, the thickness of the layer containing the curable compound, and the like. The active energy rays may be irradiated in an atmosphere of an inert gas. In order to irradiate the active energy rays in a nitrogen atmosphere, for example, the active energy rays may be irradiated in a container sealed with an inert gas, and as the inert gas, nitrogen gas, argon gas or the like can be used.
An antireflection layer and a low reflection layer, which will be described later, can be further laminated on the surface of the hard coat layer. In this case, the antireflection layer and the low reflection layer can be laminated on the surface of the hard coat layer as a single layer or as a plurality of layers.

(Antistatic function)
The antistatic function is a function of preventing the surface of the optical film from being charged. In the laminated film of the present invention, the functional layer may be a layer having an antistatic function, for example, an antistatic layer. As a method for forming the antistatic layer, in addition to the method of adding an antistatic agent to the composition for forming a hard coat layer to impart an antistatic function to the hard coat layer, the antistatic agent is diluted with a solvent or the like. Examples thereof include a method in which the obtained antistatic layer forming composition is applied onto an optical film or a functional layer laminated on the optical film, and if necessary, dried to form a single film. The antistatic agent may be contained as a structural unit having an antistatic function in a part of a resin constituting the functional layer, for example, a cured product of the above-mentioned active energy ray-curable compound, or forms the functional layer. It may be added as an additive in the resin. When the antistatic agent is added as an additive, the amount added is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, based on the solid content of the composition for forming the functional layer. %, More preferably 0.1 to 10% by mass.

(Anti-glare function)
The anti-glare function is a function of preventing reflection of external light by scattering and reflecting light. In the laminated film of the present invention, the functional layer may be a layer having an antiglare function, for example, an antiglare layer. As the antiglare layer, a known one can be appropriately adopted. For example, an antiglare function may be imparted by forming a layer having a fine uneven shape on the surface by using a resin composition containing one or more kinds of translucent fine particles in the translucent resin. More specifically, in such an antiglare layer, for example, a translucent resin solution in which translucent fine particles as a filler are dispersed is applied on an optical film, and the translucent fine particles are formed on the antiglare layer. It can be formed by adjusting the coating thickness so that it becomes a convex portion on the surface. In addition, in this specification, "translucency" means that light can be substantially transmitted regardless of the presence or absence of scattering inside a substance.

(Translucent fine particles)
Examples of the translucent fine particles include (meth) acrylic resin, melamine resin, polyethylene resin, polystyrene resin, polycarbonate resin, vinyl chloride resin, organic silicone resin, organic fine particles such as acrylic-styrene copolymer, and carbonic acid. Examples thereof include inorganic fine particles such as calcium, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, and glass. One kind or two or more kinds of fine particles can be used as the translucent fine particles. In order to obtain the desired antiglare property, the type, particle size, refractive index, content and the like of the translucent fine particles are appropriately adjusted.

The particle size of the translucent fine particles is preferably 0.5 to 5 μm, more preferably 1 to 4 μm. When the particle size of the translucent fine particles is within the above range, it is easy to obtain the necessary light diffusion effect, and since unevenness is likely to be formed on the surface of the antiglare layer, it is easy to obtain a sufficient antiglare effect. Further, the surface shape of the antiglare layer is not rough, and the haze value tends not to increase significantly.

The difference in refractive index between the translucent fine particles and the translucent resin is preferably 0.02 to 0.2, more preferably 0.04 to 0.1. When the difference in refractive index is within the above range, it is easy to obtain a sufficient light diffusion effect, and the entire laminated film is difficult to whiten.

The amount of the translucent fine particles added is preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the translucent resin. When the addition amount is within the above range, it is easy to obtain a sufficient light diffusion effect, and the entire laminated film is difficult to whiten.

When adjusting the particle size, amount of addition, and / or the difference in refractive index between the translucent fine particles and the translucent resin within the above range, even in a region where the haze of the antiglare layer is high, It is easy to prevent glare on the surface without lowering the transmission sharpness, and it is easy to prevent glare while maintaining high transmission sharpness even in a region with a low haze.

(Translucent resin)
The translucent resin constituting the antiglare layer is not particularly limited as long as it has translucency. For example, in addition to the cured product of the active energy ray-curable compound as described above, a thermosetting resin can be used. Examples thereof include a cured product, a thermoplastic resin, and a metal alkoxide polymer. Of these, a cured product of an active energy ray-curable compound is preferable. When an ultraviolet curable resin or the like is used as the active energy ray-curable compound, the coating liquid may contain a photopolymerization initiator, for example, a radical polymerization initiator, and is irradiated with active energy rays, as described above. This cures the coating layer.

Examples of the thermosetting resin include a thermosetting urethane resin composed of an acrylic polyol and an isocyanate prepolymer, a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, and a silicone resin.

Examples of the thermoplastic resin include cellulose derivatives such as acetyl cellulose, nitro cellulose, acetyl butyl cellulose, ethyl cellulose, and methyl cellulose; vinyl acetate and its copolymers, vinyl chloride and its copolymers, vinylidene chloride and its copolymers, and the like. Based resin; acetal resin such as polyvinyl formal and polyvinyl butyral; (meth) acrylic resin such as acrylic resin and its copolymer, methacrylic resin and its copolymer; polystyrene resin; polyamide resin; polyester resin; Examples include polycarbonate resins.

As the metal alkoxide-based polymer, a silicon oxide-based matrix or the like made from a silicon alkoxide-based material can be used. Specifically, the metal alkoxide-based polymer can be an inorganic-based or organic-inorganic composite-based matrix obtained by dehydration-condensing a hydrolyzate of an alkoxysilane such as tetramethoxysilane or tetraethoxysilane.

When a cured product of a thermosetting resin or a metal alkoxide polymer is used as the translucent resin, heating may be required after applying the coating liquid.

In general, the refractive index of the ultraviolet curable resin is about 1.5, which is about the same as that of glass, but the refractive index of the ultraviolet curable resin used may be low in comparison with the refractive index of the translucent fine particles. be. In this case, in the translucent resin, TiO ₂ (refractive index; 2.3 to 2.7), Y ₂ O ₃ (refractive index; 1.87), and La ₂ O ₃ (refractive index), which are fine particles having a high refractive index, are used. Rate; 1.95), ZrO ₂ (refractive index; 2.05), Al ₂ O ₃ (refractive index; 1.63), etc. are added to the extent that light diffusivity in the antiglare layer can be maintained, and transmission is performed. The refractive index of the sex resin can be increased and adjusted to a preferable range.

The antiglare layer forming composition can be produced by dispersing the translucent fine particles in a composition containing a translucent resin and a solvent, for example, the above-mentioned hard coat layer forming composition. The timing and method of dispersing the translucent fine particles are not particularly limited.

The antiglare layer can be formed by applying the antiglare layer forming composition to the surface of the optical film or the surface of the functional layer laminated on the optical film and drying the composition. The coating can be carried out by a usual method, for example, a microgravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a cast transfer method, a flow coating method, a spray coating method or the like. After that, it is preferable to cure the ultraviolet curable resin by irradiating it with ultraviolet rays. The intensity of the ultraviolet rays to be irradiated, the irradiation time, and the like are appropriately selected according to the type of the curable compound to be used, the thickness of the layer containing the curable compound, and the like. Ultraviolet rays may be irradiated in an atmosphere of an inert gas. In order to irradiate ultraviolet rays in an inert gas atmosphere, for example, active energy ray irradiation may be performed in a container sealed with an inert gas, and as the inert gas, nitrogen gas, argon gas or the like can be used.

Embossing can be used as another method of forming the antiglare layer. In this method, an optical film or a composition for forming an antiglare layer is applied onto an optical film or a functional layer laminated on the optical film, and then a mold called an embossed roll having a predetermined surface uneven shape is applied to the coated layer. The coating layer can be cured as necessary while pressing the coating layer to impart irregularities to the surface of the coating layer. After peeling the antiglare layer from the embossed roll, it is also effective to perform a second curing step of irradiating ultraviolet rays from the antiglare layer side again for the purpose of further promoting the curing reaction of the antiglare layer.

The haze of the antiglare layer is preferably 0.1 to 50%. The haze of the antiglare layer is measured by a method according to JIS K 7361. The thickness of the antiglare layer may be appropriately adjusted so that the haze of the antiglare layer is within the above range, but is preferably 2 to 20 μm. When the thickness of the antiglare layer is within the above range, it is easy to obtain a sufficient antiglare effect, it is easy to prevent the antiglare layer from cracking, and the antiglare layer is curled by the curing shrinkage of the antiglare layer. It is easy to prevent a decrease in productivity due to this. The thickness of the antiglare layer is generally preferably 85% or more, more preferably 100% or more, based on the weight average particle size of the translucent fine particles to be dispersed. When the thickness of the antiglare layer is within the above range, the haze does not become too large and the visibility tends to be difficult to decrease.

The antiglare layer may contain an antistatic agent. By containing an antistatic agent, an antiglare layer having an antistatic function can be obtained. Examples of the antistatic agent include the same antistatic agents added to the above-mentioned hard coat layer.

The antiglare layer may have a low reflection layer on its outermost surface, that is, on the uneven surface side. Even in the absence of the low-reflection layer, a sufficient anti-glare function is exhibited, but by providing the low-reflection layer on the outermost surface, the anti-glare property can be further improved. As the low reflection layer, those described later can be applied.

(Anti-reflective function and low-reflective function)
The antireflection function and the low reflection function are functions for preventing or reducing the reflection of external light. In the laminated film of the present invention, the functional layer may be a layer having a function of preventing reflection of external light (hereinafter, may be referred to as an antireflection layer), or a layer having a function of reducing reflection of external light. (Hereinafter, it may be referred to as a low reflection layer). The antireflection layer and the low reflection layer may be a single layer or a multi-layer.

(Anti-reflective layer)
The antireflection layer may include a low refractive index layer. Further, the antireflection layer is a layer having a multilayer structure further including a low refractive index layer, a high refractive index layer and / or a medium refractive index layer laminated between the low refractive index layer and the optical film. May be good. The above-mentioned hard coat layer may be provided between the antireflection layer and the optical film.

The thickness of the antireflection layer is preferably 0.01 to 1 μm, more preferably 0.02 to 0.5 μm. The antireflection layer is a low refractive index layer having a refractive index smaller than the refractive index of the optical film or functional layer on which the antireflection layer is laminated, for example, a refractive index of 1.3 to 1.45; a thin film made of an inorganic compound. Examples thereof include a layer in which a plurality of low refractive index layers and a high refractive index layer of a thin film made of an inorganic compound are alternately laminated. Here, the refractive index of the high refractive index layer may be larger than the refractive index of the low refractive index layer, but is preferably 1.60 or more.

The material forming the low refractive index layer is not particularly limited as long as it is a material having a low refractive index. For example, an active energy ray-curable resin, a resin material such as an ultraviolet curable acrylic resin, a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, and a sol-gel material using a metal alkoxide such as tetraethoxysilane. And so on. The material forming these low refractive index layers may be a polymerized polymer, or may be a monomer or an oligomer as a precursor. Moreover, since the material constituting the antireflection layer can impart an antifouling function to the antireflection layer, it is preferable to contain a compound containing fluorine.

The high refractive index layer is coated after applying a coating liquid containing a cured product of the above-mentioned active energy ray-curable resin, a translucent resin such as a metal alkoxide polymer, and inorganic fine particles and / or organic fine particles. It can be formed by a method of curing the work layer as needed. Examples of the inorganic fine particles include zinc oxide, titanium oxide, cerium oxide, aluminum oxide, silane oxide, tantalum oxide, yttrium oxide, ytterbium oxide, zirconium oxide, antimony oxide, and tin oxide (ITO). The high refractive index layer containing these inorganic fine particles may also have an antistatic function.

As a method for producing a multilayer film in which an inorganic compound having a different refractive index, for example, a transparent thin film such as a metal oxide is laminated, a colloidal metal is produced by a chemical vapor deposition method, a physical vapor deposition method, or a sol / gel method for a metal compound such as a metal alkoxide. Examples thereof include a method of forming a thin film by post-treatment after forming the oxide particle film, for example, ultraviolet irradiation described in JP-A-9-157855, plasma treatment described in, and the like.

On the other hand, from the viewpoint of easily improving productivity, it is also preferable to laminate and apply a thin film in which inorganic particles are dispersed in a matrix to laminate an antireflection layer. Further, by applying a composition for forming an antireflection layer in which inorganic particles are dispersed in a matrix, when the antireflection layers are laminated, a fine uneven shape is formed on the coated surface to prevent reflection. It is also possible to further add an anti-glare function to the layer.

(Low reflection layer)
The low-reflection layer is a layer made of a low-refractive index material having a lower refractive index than the optical film used as a base material. The low refractive index layer is coated with a coating liquid containing a cured product of the above-mentioned active energy ray-curable resin, a translucent resin such as a metal alkoxide polymer, and inorganic fine particles, and then the coating layer is applied as needed. It can be formed by a method of curing. Specific examples of such a low refractive index material include lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), and glacial stone (3NaF / AlF ₃ or Na ₃ AlF _6). ) And other inorganic material fine particles are contained in acrylic resin, epoxy resin, etc. Inorganic low-reflection material; fluorine-based or silicone-based organic compound, thermoplastic resin, thermosetting resin, ultraviolet curable resin, etc. Examples include organic low-reflection materials.

(Anti-fouling function)
The antifouling function is a function of preventing stains, and is a function obtained by imparting water repellency, oil repellency, sweat resistance, antifouling property, fingerprint resistance, and the like to the layer. In the laminated film of the present invention, the functional layer may be a layer having an antifouling function, for example, an antifouling layer. The material for forming the antifouling layer may be an organic compound or an inorganic compound. Examples of materials that provide high water repellency and oil-forming properties include fluorine-containing organic compounds and organosilicon compounds. Examples of the fluorine-containing organic compound include fluorocarbons, perfluorosilanes, and high molecular compounds thereof. From the viewpoint of easily enhancing the effect of preventing dirt adhesion, a material having a contact angle of the surface of the antifouling layer with pure water of 90 degrees or more, more preferably 100 degrees or more is preferable. As a method for forming the antifouling layer, a physical vapor deposition method, a chemical vapor deposition method, a wet coating method or the like, which is typified by thin film deposition or sputtering, can be used depending on the material to be formed. The average thickness of the antifouling layer is usually about 1 to 50 nm, preferably 3 to 35 nm.

(Ultraviolet absorption function)
In the laminated film of the present invention, the functional layer may be an ultraviolet absorbing layer having an ultraviolet absorbing function. The ultraviolet absorbing layer includes, for example, a main material selected from an ultraviolet curable type translucent resin, an electron beam curable type translucent resin, and a heat curable type translucent resin, and ultraviolet absorption dispersed in the main material. Consists of agents.

(Adhesive function)
In the laminated film of the present invention, the functional layer may be an adhesive layer having an adhesive function of adhering an optical film to another member. As a material for forming the adhesive layer, a commonly known material can be used. For example, a thermosetting resin composition or a photocurable 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 after the fact.

The adhesive layer may be a layer called a pressure-sensitive adhesive (Pressure Sensitive Adhesive, PSA), which is attached to an object by pressing. The pressure-sensitive adhesive may be an adhesive that is "a substance that has adhesiveness at room temperature and adheres to an adherend with a light pressure" (JIS K 6800), and "protects a specific component (microcapsules). ), It may be a capsule type adhesive which is "an adhesive which can maintain stability until the film is destroyed by an appropriate means (pressure, heat, etc.)" (JIS K 6800).

(Hue adjustment function)
In the laminated film of the present invention, the functional layer may be a hue adjusting layer having a function of adjusting the laminated film to a desired hue. The hue adjusting layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, petals, titanium oxide-based calcined pigments, ultramarine, cobalt aluminate, and carbon black; azo compounds, quinacridone compounds, anthracinone compounds, and perylene. Organic pigments such as compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, slene compounds, and diketopyrrolopyrrole compounds; extender pigments such as barium sulfate and calcium carbonate; and basic dyes, acidic Examples thereof include dyes and dyes such as medium dyes.

<Protective film>
In the present invention, the "protective film" is a film laminated to temporarily protect the laminated film from being damaged or deformed from the outside, and is present when the laminated film is actually used for the intended purpose. It is a film that does not. The protective film is attached to a surface without an optical film on the cured resin layer, and this protective film is called a protective film 1. Next, when the laminated film is wound into a roll, if there is a problem in winding property such as blocking, in addition to the above, a protective film is attached to the surface of the optical film without the cured resin layer. May be good. This protective film is called a protective film 2. Both the protective film 1 and the protective film 2 may be the same or different, but when the term "protective film" is simply used, both protective films are described below.

The protective film is a film for temporarily protecting the surface of the optical film, and is not particularly limited as long as it is a peelable film capable of protecting the surface of the laminated film. For example, polyester resin films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyolefin resin films such as polyethylene and polypropylene films, acrylic resin films and the like, and polyolefin resin films, polyethylene terephthalate resin films and the like. It is preferably selected from the group consisting of acrylic resin films.

The thickness of the protective film is not particularly limited, but is usually 10 to 250 μm, preferably 10 to 180 μm, and more preferably 20 to 150 μm. When the protective film is attached to both sides of the laminated film, the thickness of the protective film on each side may be the same or different, but the laminated film during storage or transportation in a high temperature environment. From the viewpoint of curl suppression, it is preferable that the relationship of Tp1> Tp2 is satisfied when the thickness of the protective film 1 is Tp1 and the thickness of the protective film 2 is Tp2. Tp1 is preferably 75 μm or more, more preferably 100 μm or more, still more preferably 120 μm or more. When Tp1 is at least the above lower limit value, moisture is less likely to escape from the laminated film as a whole, so that deterioration of winding habit can be prevented, and curl of the laminated film when unwound from the film roll tends to be small. The upper limit of Tp1 is preferably 200 μm or less from the viewpoint of film roll productivity. Further, Tp1 / Tp2 is preferably 1.1 or more and 6 or less, more preferably 1.2 or more and 5 or less, and further preferably 1.3 or more and 4 or less. When Tp1 / Tp2 is in the above range, the warpage that occurs when the protective film 1 and the protective film 2 also shrink is balanced, and curl is less likely to occur.

<Film roll>
In the present invention, the combination of the above-mentioned optical film and the laminated film having the cured resin layer and the protective film 1, or the combination of the protective film 2, the laminated film having the optical film and the cured resin layer, the protective film 1 and the like are wound around the roll core. What is done is called a film roll. The film roll is often temporarily stored in the form of a roll in a continuous manufacturing process due to space and other restrictions, and the film roll of the present invention is one of them. In the present invention, it is necessary that the winding method of the film roll is in the order of the optical film, the cured resin layer which is the functional layer, and the protective film 1 from the core side of the roll. When the protective film 2 is present, it is necessary that the protective film 2, the optical film, the cured resin layer which is the functional layer, and the protective film 1 are in this order from the core side of the roll. When the film rolls are formed in this order, curling does not occur or is reduced when the film roll is rewound and used even when stored in a high-temperature drying environment. As described above, the term "curl" as used herein means that when one surface of the laminated film is placed on a flat surface, the end portion of the laminated film is separated from the flat surface. The curl is measured by the method for measuring the curl amount described in Examples, and the curl amount is specified. The amount of curl is said to be larger when the laminated film is placed on a flat surface and the distance between the ends away from the flat surface is large. The curl amount is preferably 10 mm or less, more preferably 7 mm or less, still more preferably 5 mm or less, from the viewpoint of ease of handling of the unwound film.

In the present invention, from the viewpoint of reducing the curl of the laminated film due to the strong curl of the film roll in a high temperature environment, the cured resin layer, which is a functional layer in which water does not easily escape, is outside the laminated film layer. That is, it is arranged on the side away from the roll core. Therefore, when the laminated film is wound, if the optical film is placed on the roll core side, the cured resin layer having a function is placed on the outside, and the protective film 1 is placed on the outside, the protective film 1 is placed in a high temperature environment, especially in a high temperature drying environment. Since the cured resin layer and the protective film 1 which are functional layers in which water does not easily escape are located on the outside, the curl of the laminated film unwound from the film roll, particularly the curl of the laminated film located in the outermost layer is reduced.

The water absorption rate of the laminated film is measured by the method described in Examples as in the case of curling. To briefly explain the measuring method, a film having a specific size, for example, 100 mm × 100 mm, is cut out from a laminated film wound into a roll, and the film is once sufficiently dried and not absorbed by water. Is measured, and this is taken as the mass W0 of the laminated film before exposure to water vapor. Next, the opening of the beaker that is boiling and steam is cut out, the opening is covered with a laminated film, the mass of the laminated film in a water-absorbed state after 5 minutes has passed, and the measurement result is the result of the laminated film after steam exposure. Let the mass be W1. The water absorption rate is represented by (W1-W0) / W0 × 100. As is clear from this measurement, the water absorption rate expressed by the above formula is not the water absorption rate of each layer of the laminated film but the water absorption rate calculated from the mass of the entire laminated film, and is in contact with steam when the laminated film is measured. The water absorption rate of the laminated film changes depending on the ease of absorption of water vapor on the surface.

In general, a film having a high water absorption rate is more likely to take in water and, conversely, to remove water more easily. Normally, when the moisture in the film is removed, the film shrinks, but when the moisture is released unevenly on the front and back sides of the film, the film shrinks to the side where the amount of moisture removed is large, and the shrinking side becomes the inside and curls occur. In a high-temperature drying environment, moisture easily escapes from the entire thickness direction of the film, and when the film is rolled and exposed to a high-temperature drying environment, the curl becomes worse, that is, the wrapping inside the roll becomes stronger, especially. Laminated films near the outermost layer of the film roll may show very large curls. A film having a low water absorption rate does not easily release moisture and is less likely to affect the curl of the laminated film due to the storage environment of the film roll. In the film roll of the present invention, the film roll is wound with the optical film side on the inside, that is, the roll core side, the cured resin layer side is on the outside, and the protective film 1 is further on the outside. When the environment for transporting, transporting, or storing the film roll is a high-temperature drying environment, if the optical film on which moisture easily escapes is on the outside, the moisture in the thickness direction of the optical film escapes, and the laminated film becomes stronger on the inside of the roll. Although it wraps around, in the present invention, since the cured resin layer in which water does not easily escape and the protective film 1 are on the outside, there is almost no inflow and outflow of moisture even in a high-temperature drying environment, the laminated film is less deformed, and the curl is also small. Further, in general, since the solvent used at the time of production remains in the optical film, the solvent is likely to be desorbed in a high temperature drying environment, but in the film roll of the present invention, the solvent is released. Curling due to can also be suppressed.

The water absorption rate of the laminated film when the optical film side is exposed to water vapor is preferably larger than 0.75%, more preferably 1.00% or more and 3.00% or less, and further preferably 1.05% or more. It is 00% or less, more preferably 1.10% or more and 1.80% or less, and particularly preferably 1.20% or more and 1.70% or less. When the water absorption rate of the laminated film on the optical film side is within the above range, a large warp of the optical film is unlikely to occur when water is removed from the film, and as a result, the laminated film is curled when unwound from the film roll. Is easy to get smaller. The water absorption rate of the laminated film when the cured resin layer side is exposed to water vapor is preferably 1.30% or less, more preferably 0.10% or more and 1.20% or less, and further preferably 0.50% or more 1. It is 10% or less, particularly preferably 0.75% or more and 1.05% or less. When the water absorption rate on the cured resin layer side of the laminated film is within the above range, it is difficult for water to escape from the cured resin layer side, and the film roll wound so that the cured resin layer side of the laminated film is on the outside. Since it is difficult for moisture to escape from the laminated film as a whole, deterioration of winding habit can be prevented, and the curl of the laminated film unwound from the film roll tends to be small. In the present invention, the water absorption rate of the cured resin layer is preferably lower than that of the optical film of the laminated film, and the water absorption rate when the cured resin layer side of the laminated film is exposed to water vapor and the water absorption rate when the optical film side is exposed to water vapor. The ratio to the water absorption rate, in other words, the water absorption rate when the cured resin layer side is exposed to water vapor / the water absorption rate when the optical film side is exposed to water vapor is preferably 0.25 or more and 0.95 or less, more preferably. It is 0.33 or more and 0.90 or less, more preferably 0.5 or more and 0.85 or less, and particularly preferably 0.65 or more and 0.83 or less. When the ratio of the water absorption rates on both sides of the laminated film is within the above range, the stress applied to the cured resin side of the laminated film and the stress applied to the optical film side tend to cancel each other out, and the laminated film curls when unwound from the film roll. Is easy to get smaller.

In the present invention, the optical film constituting the laminated film is preferably 0.02% or more and 1.5% or less, more preferably 0.1% or more and 1.2% or less, still more preferably, with respect to the mass of the optical film. May contain 0.3% or more and 1.1% or less, particularly preferably 0.5% or more and 1.0% or less of a solvent. When the content of the solvent is within the above range, a large warp of the optical film is less likely to occur when water is removed from the optical film.

The amount of solvent in the optical film can be adjusted by the drying conditions and annealing conditions at the time of manufacturing the optical film, for example, temperature and time. The temperature of the annealing treatment is preferably 120 to 350 ° C, more preferably 150 to 300 ° C, and even more preferably 170 to 250 ° C. The annealing treatment time can be appropriately set according to the annealing temperature. For example, when the annealing temperature is 200 ° C., the annealing treatment time is preferably more than 20 minutes and 350 minutes or less, more preferably 21 minutes or more and 200 minutes or less. It is more preferably 22 minutes or more and 150 minutes or less, even more preferably 23 minutes or more and 120 minutes or less, and particularly preferably 25 minutes or more and 60 minutes or less. The annealing treatment may be carried out in the air, in an inert atmosphere or under reduced pressure conditions, but is usually carried out in the air.

The laminated film of the present invention has a surface hardness of 2B or more on the cured resin layer side, and the surface hardness is represented by, for example, a pencil hardness. The pencil hardness of the laminated film is preferably B or more and 7H or less, more preferably HB or more and 6H or less, and further preferably H or more and 5H or less. The pencil hardness can be measured according to JIS K 5600-5-4: 1999, and can be measured, for example, by the method described in Examples. When the pencil hardness of the laminated film is within the above range, it is possible to prevent deterioration of the curl when moisture is removed from the entire thickness direction of the laminated film of the film roll, and it is easy to reduce the curl amount.

As a material constituting the core of the film roll, for example, synthesis of polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyester resin, epoxy resin, phenol resin, melamine resin, silicon resin, polyurethane resin, polycarbonate resin, ABS resin and the like. Examples thereof include resin; metal such as aluminum; fiber-reinforced plastic (sometimes abbreviated as FRP) which is a composite material in which fibers such as glass fiber are contained in plastic to improve strength. The winding core has a cylindrical or columnar shape, and its diameter is, for example, 80 to 170 mm. The diameter of the film roll after winding is not particularly limited, but is usually 200 to 800 mm.

The width of the film roll is not particularly limited, but when the width of the optical film is L1 and the width of the cured resin layer is L2, it is preferable that L1> L2 from the viewpoint of easily improving the curl of the laminated film, and L2 /. L1 is preferably 0.80 or more and 0.98 or less, more preferably 0.85 or more and 0.97 or less, and further preferably 0.90 or more and 0.96 or less. When L1 is 500 mm or more, L1-L2 is preferably 20 mm or more and 90 mm or less, more preferably 25 mm or more and 80 mm or less, and further preferably 30 mm or more and 70 mm or less.
Further, when the width of the protective film 1 is L3, it is preferable that L1>L3> L2, and when L1> L3, when the protective film 1 has an adhesive layer, it depends on the adhesive of the laminated body or the laminated film. Contamination can be prevented. L3 / L2 is preferably 1.030 or more and 1.070 or less, more preferably 1.035 or more and 1.060 or less, and further preferably 1.040 or more and 1.060 or less. L3-L2 is 25 mm or more and 75 mm or less, preferably 20 mm or more and 70 mm or less, more preferably 35 mm or more and 65 mm or less, and further preferably 40 mm or more and 60 mm or less. When L3 / L2 and L3-L2 are equal to or higher than the lower limit, when the protective film 1 shrinks during transportation and transportation, the protective film 1 in the outermost layer warps in the direction opposite to the winding direction and inward. It is in harmony with the warp of the existing laminated film (optical film + cured resin layer), and it is easier to exhibit curl resistance. When it is not more than the upper limit values of L3 / L2 and L3-L2, it is easy to reduce the warp generated on the side opposite to the winding direction due to the shrinkage of the protective film 1. The protective film 2 may have the same length as the protective film 1 or may be different.

<Manufacturing method of film roll>
The method for producing the film roll of the present invention having the above characteristics is not particularly limited, but for example, the following steps:
(A) A step of applying a polyimide resin and / or a polyamide resin and a resin varnish containing at least a solvent onto a support, drying the resin, and forming a coating film.
(B) Step of peeling the coating film from the support,
(C) A step of heating the peeled coating film to obtain an optical film, and (d) a step of laminating a cured resin layer having a function on the film (e) A protective film 1 is placed on the cured resin layer side of the obtained film. , A step of coating the optical film side with the protective film 2 to obtain a laminated film, if necessary.
(F) The obtained laminated film can be produced by a production method including at least a step of rotating the optical film on the winding core side.

The resin varnish used in the above step (a) contains at least a polyimide resin and / or a polyamide resin and a solvent. Examples of the resin and solvent contained in the resin varnish include the resins described above as the resin contained in the optical film. Further, the resin varnish may contain additives such as the above-mentioned inorganic materials. The solid content concentration of the resin varnish is preferably 1 to 25% by mass, more preferably 5 to 20% by mass.

The resin varnish can be prepared by mixing the above-mentioned polyimide-based resin and / or polyamide-based resin, solvent, and additives used as necessary, and stirring the mixture.

The viscosity of the resin varnish is preferably 5,000 to 60,000 cps, more preferably 10,000 to 50,000 cps, and even more preferably 15,000 to 45,000 cps. When the viscosity of the resin varnish is at least the above lower limit, the effect of the present invention can be easily obtained, and when it is at least the above upper limit, the handling of the resin varnish can be easily improved.

The solid content concentration of the resin varnish is preferably 5 to 25% by mass, more preferably 10 to 23% by mass, and further preferably 14 to 20% by mass. It is preferable that the solid content concentration of the resin varnish is at least the above lower limit from the viewpoint of obtaining a thick film, and it is preferable that the solid content concentration is at least the above upper limit from the viewpoint of ease of handling of the resin varnish.

Examples of the support include a resin base material, a stainless steel belt, a glass base material, and the like. It is preferable to use a resin film base material as the support. Examples of the resin film base material include polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, cycloolefin-based (COP) film, acrylic film, polyimide film, polyamideimide film and the like. Among them, PET film, COP film and the like are preferable from the viewpoint of excellent smoothness and heat resistance, and PET film is more preferable from the viewpoint of adhesion to an optical film and cost.

The thickness of the support is not particularly limited, but is preferably 50 to 250 μm, more preferably 100 to 200 μm, and even more preferably 125 to 200 μm. When the thickness of the support is not more than the above upper limit, it is preferable because the manufacturing cost of the optical film can be easily suppressed. Further, it is preferable that the thickness of the support is at least the above lower limit because it is easy to suppress the curl of the film that may occur in the step of removing at least a part of the solvent. Here, the thickness of the support is measured by a contact-type film thickness meter or the like.

When the resin varnish is applied onto the support, it may be applied to the support by a known application method. Known coating methods include, for example, wire bar coating method, reverse coating, roll coating method such as gravure coating, die coating method, comma coating method, lip coating method, spin coating method, screen coating method, fountain coating method, dipping method, and the like. Examples include a spray method and a salivation molding method.

Next, the coating film can be formed by drying the coating film of the resin varnish applied on the support. The drying is performed by removing at least a part of the solvent from the coating film of the resin varnish, and the drying method is not particularly limited. For example, the coating film of the resin varnish applied on the support may be heated for drying.

Next, in the step (b), the dried coating film is peeled off from the support. The peeling method is not particularly limited, and the coating film may be moved and peeled while the support is fixed, or the support may be moved and peeled while the coating film is fixed. Then, the peeling may be performed by moving both the coating film and the support.

Next, in the step (c), an optical film can be obtained by heating the coating film peeled off in the step (b). In the step (c), it is preferable to carry out drying in a state where the release coating film is stretched in the in-plane direction. The heating temperature during drying is preferably 150 to 300 ° C, more preferably 180 to 250 ° C, and even more preferably 180 to 230 ° C. The heating time during drying is preferably 10 to 60 minutes, more preferably 30 to 50 minutes.

The amount of solvent in the film after the heat treatment is preferably 0.001 to 3% by mass, more preferably 0.001 to 2% by mass, still more preferably 0.001 to 1.5% by mass, based on the mass of the film. , Particularly preferably 0.001 to 1.3% by mass. When the amount of the solvent in the film after the heat treatment is in the above range, the appearance of the optical film tends to be good.

Next, in the step (d), a cured resin layer having a function is laminated on one side of the optical film. As a method of laminating a cured resin layer having a function on one side of a film, a composition for forming a cured resin layer having a function is applied to the film, and if necessary, dried and / or cured to be laminated. , A method of laminating a cured resin layer having a film-like function on one side of an optical film can be mentioned. From the viewpoint of easily enhancing the optical homogeneity of the laminated film, it is preferable to apply and form a composition for forming a cured resin layer having a function.

Further, in the step (e), the protective film 1 is coated on the cured resin layer side of the obtained film, and the protective film 2 is coated on the optical film side, if necessary, to obtain a laminated film. As described above, the protective film is laminated to protect the surface on which the film-like material is desired to be protected. The protective film 2 is formed as needed, and the protective film 1 is indispensable.

Next, the film roll of the present invention can be obtained by performing a step of rotating the laminated film obtained in the step (f) with the optical film on the winding core side.

In the present invention, the winding order of the film roll is controlled. That is, the film roll of the present invention is simply wound from the core side of the roll in the order of the optical film, the cured resin layer, and the protective film 1, and when stored in a high-temperature drying environment, the curl of the laminated film at the time of unwinding, particularly the film. Since the curl of the laminated film in the outermost layer portion of the roll is eliminated or reduced, the curl of the laminated film unwound from the film roll can be prevented very easily, and its technical usefulness is very high. When the protective film 2 is present, the film roll of the present invention is wound in the order of the protective film 2, the optical film, the cured resin layer, and the protective film 1 from the core side of the roll. Normally, the outermost laminated film has a large curl and is not suitable for use, so it is discarded. However, when the film roll of the present invention is used, there is no or less part to be discarded, which is very economical and wasteful. Is highly effective.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "part" in the example mean mass% and parts by mass.

First, the measurement methods will be described together.
<Weight average molecular weight>
Gel permeation chromatography measurement (1) Pretreatment method Dissolve the sample in γ-butyrolactone to make a 20% by mass solution, and then add 100 times with N, N-dimethylformamide (sometimes referred to as DMF) eluent. The solution was diluted and filtered through a 0.45 μm membrane filter to prepare a measurement solution.
(2) Measurement condition column: TSKgel SuperAWM-H × 2 + SuperAW2500 × 1 (inner diameter 6.0 mm, length 150 mm, 3 connected)
Eluent: DMF (10 mmol / L lithium bromide added)
Flow rate: 0.6 mL / min Detector: RI detector Column temperature: 40 ° C
Injection volume: 20 μL
Molecular weight standard: Standard polystyrene

<Imidization rate>
The imidization ratio was ^{determined by 1} H-NMR measurement as follows.
(1) Pretreatment Method A sample _{was dissolved in deuterated dimethyl sulfoxide (sometimes referred to as DMSO-d 6} ) to prepare a 2% by mass solution, which was used as a measurement solution.
(2) Measuring conditions Measuring device: JEOL 400MHz NMR device JNM-ECZ400S / L1
Standard substance: DMSO-d ₆ (2.5 ppm)
Sample temperature: Room temperature Integral number: 256 times Relaxation time: 5 seconds (3) ^{Imidization rate analysis method In the obtained 1} H-NMR spectrum, benzene protons were observed at 7.0 to 9.0 ppm, of which imidization was performed. The integral ratio of benzene proton A derived from the structure that does not change before and after was defined as Int _A. Further, amide protons having an amic acid structure remaining in the polyimide were observed at 10.5 to 11.5 ppm, and this integration ratio was defined as Int _B. From these integration ratios, the imidization ratio was calculated by the following formula.

上記式において、αは、イミド化率０％のポリアミド酸の場合におけるアミドプロトン１個に対するベンゼンプロトンＡの個数割合である。

In the above formula, α is the number ratio of benzene protons A to one amide proton in the case of a polyamic acid having an imidization ratio of 0%.

<Varnish viscosity>
The measurement was performed using an E-type viscometer DV-II + Pro manufactured by Brookfield Co., Ltd. in accordance with JIS K 8803: 2011. The measurement temperature was 25 ° C.

<Film thickness>
Using ID-C112XBS manufactured by Mitutoyo Co., Ltd., the thickness of 10 or more films was measured, and the average value was calculated.

<Measurement of pencil hardness>
The pencil hardness on the surface of the cured resin layer of the laminated film was measured according to JIS K 5600-5-4: 1999. The load at the time of measurement was 750 gf, and the measurement speed was 4.5 mm / sec.

<Measurement method of residual solvent>
Using TG-DTA (EXSTAR6000 TG / DTA6300 manufactured by SII Co., Ltd.), the optical film portion of the laminated film obtained in Example 1 was heated from 30 ° C. to 120 ° C. and held at 120 ° C. for 5 minutes. After that, the temperature was raised to 400 ° C. at a heating rate of 5 ° C./min. The ratio of the mass reduction of the optical film from 120 ° C. to 250 ° C. to the mass of the optical film at 120 ° C. was calculated as the content of the solvent contained in the optical film (referred to as the residual solvent amount). The amount of residual solvent in the optical film indicates the ratio of the solvent contained in the optical film to the mass of the optical film.

The abbreviations used in the following production examples and examples are as follows.
TFMB: 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl 6FDA: 4,4'-(hexafluoroisopropyridene) diphthalic acid dianhydride TPC: terephthaloyl chloride OBBC: 4,4 '-Oxybis (benzoyl chloride)
DMAc: N, N-dimethylacetamide GBL: γ-butyrolactone PET: polyethylene terephthalate

<Manufacturing example>
Production Example 1: Production of Polyamide-imide Resin 1 Under a nitrogen gas atmosphere, a reaction vessel equipped with a stirring blade in a separable flask and an oil bath were prepared. 45 parts of TFMB and 768.55 parts of DMAc were put into a reaction vessel installed in an oil bath. TFMB was dissolved in DMAc while stirring the contents in the reaction vessel at room temperature. Next, 19.01 parts of 6FDA was further charged into the reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 3 hours. Then, 4.21 parts of OBBC and then 17.30 parts of TPC were put into the reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 1 hour. Next, 4.63 parts of 4-methylpyridine and 13.04 parts of acetic anhydride were further added to the reaction vessel, and the contents in the reaction vessel were stirred at room temperature for 30 minutes. After stirring, the temperature inside the container was raised to 70 ° C. using an oil bath, maintained at 70 ° C., and stirred for another 3 hours to obtain a reaction solution.

The obtained reaction solution was cooled to room temperature and poured into a large amount of methanol in the form of filaments to precipitate a precipitate. The obtained precipitate was taken out, immersed in a large amount of methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C. to obtain a polyamide-imide resin 1. The weight average molecular weight of the obtained polyamide-imide resin 1 was 400,000, and the imidization ratio was 99.0%.

Production Example 2: Preparation of Silica Sol 1 An amorphous silica sol having an average primary particle size of 27 nm measured by the BET method, which was produced by the sol-gel method, was used as a raw material, and a GBL-substituted silica sol was prepared by solvent substitution. The obtained sol was filtered through a membrane filter having an opening of 10 μm to obtain GBL-substituted silica sol 1. The content of silica particles in the obtained GBL-substituted silica sol was 30% by mass.

Production Example 3: Preparation of Resin Varnish 1 for Optical Film The polyamide-imide resin 1 obtained in Production Example 1 and the GBL-substituted silica sol 1 obtained in Production Example 2 are combined with the polyamide-imide resin: silica particles in GBL. Was mixed so that the composition ratio of the above was 60:40. In the obtained mixed solution, 2.0 phr Sumisorb (registered trademark) 250 (molecular weight 389, manufactured by Sumika Chemtex Co., Ltd.) and the total amount of the polyamide-imide resin and the silica particles with respect to the total mass of the polyamide-imide resin and the silica particles. Sumiplast (registered trademark) Violet B (manufactured by Sumika Chemtex Co., Ltd.) of 35 ppm by mass was added and stirred until uniform to obtain a resin varnish 1. The solid content of the resin varnish 1 was 9.7% by mass, and the viscosity at 25 ° C. was 39,600 cps.

Production Example 4: Photocurable Resin Composition 1
Trimethylol propantriacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMPT) 28.4 parts by mass, pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMMT) 28.4 parts by mass, photopolymerization started As an agent, 1-hydroxycyclohexylphenylketone (manufactured by BASF Co., Ltd., Irgacure (registered trademark) 184) 1.8 parts by mass, lithium bis (fluorosulfonyl) imide (manufactured by Tokyo Chemical Industry Co., Ltd., LiFSI) 2.4 Light by stirring and mixing 0.1 parts by mass, leveling agent (manufactured by Big Chemie Japan Co., Ltd., BYK-307) by 0.1 parts by mass, and 39 parts by mass of propylene glycol-1-monomethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.). A curable resin composition 1 was obtained.

Production Example 5: Production of Film Roll 1 The resin varnish 1 obtained in Production Example 3 is used as a long PET film base material having a width of 900 mm (Cosmo Shine (registered trademark) A4100; manufactured by Toyobo Co., Ltd., thickness 188 μm). , Thickness distribution ± 2 μm), and a coating film of resin varnish was formed. At this time, the linear velocity was 0.8 m / min. The coating film of the resin varnish is heated at 80 ° C. for 10 minutes, then at 100 ° C. for 10 minutes, then at 90 ° C. for 10 minutes, and finally at 80 ° C. for 10 minutes. A coating film was formed. Then, the coating film was peeled off from the PET film to obtain a raw material optical film 1 in the form of a film roll having a thickness of 48 μm, a width of 700 mm, and a length of 500 m. Next, the raw material optical film 1 is heated at 200 ° C. for 25 minutes under the conditions of a draw ratio of 0.98 times in a film transverse stretching device called a tenter to obtain a film roll 1 made of a polyamide-imide film having a thickness of 40 μm. Obtained.

Production Example 6: Production of Film Roll 2 The resin varnish 1 obtained in Production Example 3 is used as a long PET film base material having a width of 900 mm (Cosmo Shine (registered trademark) A4100; manufactured by Toyobo Co., Ltd., thickness 188 μm). , Thickness distribution ± 2 μm), and a coating film of resin varnish was formed. At this time, the linear velocity was 0.8 m / min. The coating film of the resin varnish is heated at 80 ° C. for 10 minutes, then at 100 ° C. for 10 minutes, then at 90 ° C. for 10 minutes, and finally at 80 ° C. for 10 minutes. A coating film was formed. Then, the coating film was peeled off from the PET film to obtain a raw material optical film 1 in the form of a film roll having a thickness of 48 μm, a width of 700 mm, and a length of 500 m. Next, the raw material optical film 1 was heated at 200 ° C. for 25 minutes under the conditions of a draw ratio of 0.98 times in a film transverse stretching device called a tenter to obtain a film made of a polyamide-imide film having a thickness of 40 μm. A PET film with an adhesive layer (thickness 38 μm, adhesive layer thickness 15 μm, width 680 mm) was laminated and wound to obtain a film roll 2.

Example 1
The photocurable resin composition 1 was applied to the central portion of one side of the obtained film roll 1 by a roll-to-roll method with a bar coater so that the thickness after drying was 10 μm and the width was 650 mm. .. Then, it was dried in an oven at 80 ° C. for 3 minutes, and was ^{cured by irradiating it with ultraviolet rays with an energy of 500 mJ / cm 2} of a high-pressure mercury lamp to form a cured resin layer having a hard coat function. A PET film with an adhesive layer (PET layer thickness 125 μm, adhesive layer thickness 10 μm and width 680 mm) is laminated on the cured resin layer so that the centers in the width direction coincide with each other, and the film is wound to have a length of 400 m. The laminate 1 of the above was obtained in the form of a film roll. At this time, the roll core side was wound so as to be an optical film layer. A part was cut out from the wound film roll, the PET film was peeled off, and the pencil hardness of the cured resin layer was measured and found to be 2H. The amount of residual solvent in the optical film portion on which the cured resin layer was not formed was measured and found to be 0.82%.

Example 2
The laminate 2 was obtained in the form of a film roll by the same method except that the film roll 2 was used instead of the film roll 1. At this time, the laminated body was wound so that the optical film side was the roll core side. A part was cut out from the wound film roll, the PET film was peeled off, and the pencil hardness of the cured resin layer was measured and found to be 2H. The amount of residual solvent in the optical film portion on which the cured resin layer was not formed was measured and found to be 0.82%.

Example 3
A film having a width direction of 150 mm and a winding direction of 200 mm was cut out from the central portion of one side of the obtained film roll 1. At both ends in the width direction, 5 mm from the end was masked with Kapton tape, and the curable resin composition 1 was coated with a bar coater so that the thickness after drying was 10 μm and the width was 140 mm. That is, the cured resin layer is not coated 5 mm from both ends in the width direction. Then, it was dried in an oven at 80 ° C. for 3 minutes, and was ^{cured by irradiating it with ultraviolet rays with an energy of 500 mJ / cm 2} of a high-pressure mercury lamp to form a cured resin layer having a hard coat function. A PET film with an adhesive layer (PET layer thickness 125 μm, adhesive layer thickness 10 μm and width 147 mm) was bonded onto the cured resin layer so that the centers in the width direction coincided with each other to obtain a laminate 3. When the PET film was peeled off and the pencil hardness of the cured resin layer was measured, it was 2H. The amount of residual solvent in the optical film portion on which the cured resin layer was not formed was measured and found to be 0.82%.

<Measurement of curl amount 1>
Laminates 1 and 2 having a width direction of 150 mm and an unwinding direction of 200 mm are cut out from the film rolls 1 and 2 produced in Examples 1 and 2, respectively, and the film roll and the winding direction are formed on a polyvinyl chloride core having a diameter of 3 inches. The film was wound in the same direction and left in a dry environment at 90 ° C. for 3 hours. The winding order around the core is as described in Experiments 1 and 2 below. Then, after peeling from the core, the PET films on both sides were quickly peeled off, the laminate was placed on a horizontal table, and the amount of curl at the four corners was measured. The curl amount when the cured resin layer was down was set to minus, the curl amount when the optical film was down was set to plus, and the curls at the four corners were obtained, and the average value was taken as the curl amount. A JIS 1st grade metal scale was used for the measurement.

Experiment 1
When it was wound around the polyvinyl chloride core, it was wound so that the optical film side of the cut-out laminates 1 and 2 was on the roll core side, respectively, and then the curl amount was measured according to the procedure for measuring the curl amount.

Experiment 2
When it was wound around the polychlorinated vinyl core, it was wound so that the cured resin layer side of the cut-out laminates 1 and 2 was on the roll core side, respectively, and then the curl amount was measured according to the procedure for measuring the curl amount.

<Measurement of curl amount 2>
The film rolls of the laminate 1 having a width direction of 150 mm and the unwinding direction of 200 mm cut out from the laminate 1 produced in Example 1 and the laminate 3 produced in Example 3 on a polyvinyl chloride core having a diameter of 2 inches, respectively. The film was wound in the same direction and left in a dry environment at 90 ° C. for 3 hours. At this time, it was wound around the polyvinyl chloride core so that the roll core side was the optical film side. Then, after peeling from the core, the PET film on the cured resin layer side was quickly peeled off, the laminate was placed on a horizontal table, and the amount of curl at the four corners was measured. The curl amount when the cured resin layer was down was set to minus, the curl amount when the optical film was down was set to plus, and the curls at the four corners were obtained, and the average value was taken as the curl amount. A JIS 1st grade metal scale was used for the measurement.

<Measurement of water absorption rate>
A laminated film having a width direction of 100 mm and an unwinding direction of 100 mm was cut out from the outermost layer portion of the film roll. After drying at 80 ° C. for 3 hours, the mass of the laminated film was measured and set to the mass W0 before exposure to water vapor.

A cylindrical beaker having a diameter of 75 mm was prepared, 150 g of water was placed therein, and the beaker was placed on a hot plate set at 120 ° C. to bring the water to a boil. While boiling, it was covered with a metal plate to prevent steam from escaping. After boiling sufficiently, the lid of the metal plate was removed, the lid was covered with a laminated film cut out in advance, and the top was further covered with a metal plate and exposed to steam. After 5 minutes, the laminated film was taken out and the mass was measured to obtain the mass W1 after exposure to water vapor, and the water absorption rate was calculated from the following formula. The results are shown in Table 2.

Experiment 3
The surface in contact with the vapor was covered with an optical film, and the water absorption rate was measured.

Experiment 4
The surface in contact with the steam was covered with a cured resin layer having a hard coat function, and the water absorption rate was measured.

From Table 3, it can be seen that the water absorption rate is higher when the surface in contact with the vapor is an optical film. For this reason, the optical film absorbs and releases moisture more easily than the cured resin layer, and is therefore affected by the humidity in the storage environment. Since the curl amount is measured under a drying condition of 90 ° C., the roll with the cured resin layer on the outside is not affected by the water content so that the curl amount is less affected by the water content. On the other hand, when the optical film is rotated outward, moisture is removed at once in a dry environment at 90 ° C., and curling occurs. This can also be said from the fact that Experiment 1 was better than Experiment 2 in the curl amount measurement in which the curl amount of the roll was simulated.

Claims (4)

An optical film containing a polyimide resin and / or a polyamide resin,
A laminated film containing a cured resin layer laminated on the optical film, and
A film roll formed by winding a laminate containing a protective film 1 laminated on the opposite side of the cured resin layer to the optical film.
The film roll is a film roll in which an optical film, a cured resin layer, and a protective film 1 are wound in this order from the core side of the roll. An optical film containing a polyimide resin and / or a polyamide resin,
A laminated film containing a cured resin layer laminated on the optical film, and
A protective film 1 laminated on the opposite side of the cured resin layer to the optical film,
A film roll formed by winding a laminate containing a protective film 2 laminated on the opposite side of the cured resin layer of the optical film.
The film roll is a film roll in which the protective film 2, the optical film, the cured resin layer, and the protective film 1 are wound in this order from the core side of the roll. The cured resin layer according to claim 1 or 2, wherein the cured resin layer has one or more functions selected from the group consisting of a hard coat function, an antistatic function, an antiglare function, a low reflection function, an antireflection function and an antifouling function. Film roll. The film roll according to any one of claims 1 to 3, wherein the cured resin layer is a UV curable resin layer.