TW201922868A - Optical film being excellent in bending resistance and producing excellent stability in terms of optical properties under high temperature and high humidity - Google Patents

Abstract

An object of the present invention is to provide an optical film which is excellent in bending resistance and producing excellent stability in terms of optical properties under high temperature and high humidity. The optical film of the present invention contains a polyamide-imide resin and satisfies the relationship in the formula (1): [Delta]Hz < 0.5 (1). (In the formula (1), [Delta]Hz represents Hza-Hzb; Hza represents the haze (%) of the optical film after the mandrel test (according to JIS K 5600-5-1:1999), which the bending radius of 1 mm is restored to a planar shape after bending once at room temperature; Hzb represents the haze (%) of the optical film before the mandrel test.).

Description

Optical film

The invention relates to an optical film used as a material of a flexible display.

Image display devices such as liquid crystal display devices or organic EL (Electroluminescence) display devices are widely used in various applications such as mobile phones or smart watches. Glass has been used as the front panel of such image display devices, but the glass is very rigid and easily broken, so it is difficult to use as a front panel material for flexible displays. As one of the materials for replacing glass, there is polyimide amide imide resin, and research has been conducted on a polyimide amide imide film having high heat resistance, etc., using the polyimide amide imide resin (for example, Patent Document 1) .
[Prior Technical Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Special Publication No. 2014-528490

[Problems to be solved by the invention]

However, according to the research of the present inventors, it is known that when such a polyimide amide imide film (optical film) is used as a flexible display material, it has stability in bending resistance or optical characteristics under high temperature and high humidity. Insufficient circumstances.

Therefore, an object of the present invention is to provide an optical film having excellent bending resistance and excellent stability of optical characteristics at high temperature and high humidity.
[Technical means to solve the problem]

The inventor of the present invention worked hard to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention includes the following preferred aspects.
[1] An optical film, which is made of polyimide amide imide resin and satisfies the relationship of formula (1):
ΔHz ＜ 0.5 (1)
[In formula (1), ΔHz represents Hz _a- Hz _b , Hz _a represents _a mandrel test that bends once at a bending radius of 1 mm and returns to a planar shape at room temperature (according to JIS K 5600-5-1: The haze (%) of the optical film after 1999), Hz _b represents the haze (%) of the optical film before the mandrel test].
[2] The optical film according to [1], wherein the polyamidoamide resin includes a structural unit derived from a dicarboxylic acid compound, a structural unit derived from a tetracarboxylic acid compound, and a diamine compound The resin of the structural unit, and further contains silica particles with an average primary particle size of 100 nm or less.
[3] The optical film according to [2], wherein the average primary particle diameter of the silicon dioxide particles is 80 nm or less.
[4] The optical film according to [2] or [3], wherein the structural unit derived from the dicarboxylic acid compound constituting the polyamidoamide resin includes the formula (I)
[Chem 1]

[In formula (I), R ¹ and R ² each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ³ to R ⁶ each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ³ to R ⁶ may be independently substituted by halogen atoms]
The structural unit of the compound represented, and satisfy the relationship of formula (2):
0 ＜ R _Si ≦ 32 ＋ 2/3 × R _(I) (2)
[In formula (2), R _Si represents the content (mass%) of _silicon dioxide particles relative to the mass of the optical film, and R _(I) represents the structural unit derived from the compound represented by formula (I) relative to the constituent polyacrylamide The content of the total number of moles of all structural units of the amide imine resin (mol%)].
[5] The optical film according to [4], wherein the above formula (2) is 5 ≦ R _Si ≦ 50.
[6] The optical film according to any one of [2] to [5], wherein the structural unit derived from the tetracarboxylic acid compound that constitutes the polyamidoamide resin includes the formula (II)
[Chem 2]

[In formula (II), R ⁷ to R ¹⁴ each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ⁷ to R ¹⁴ may be Independently substituted by a halogen atom]
The structural unit of the compound represented, and the structural unit derived from the diamine compound constituting the above-mentioned polyamidoamide resin includes the formula (III)
[Chemical 3]

[In formula (III), R ¹⁵ to R ²² each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ¹⁵ to R ²² may be Independently substituted by a halogen atom]
The structural unit of the compound represented.
[7] The optical film as described in any one of [2] to [6], wherein the structural unit derived from the dicarboxylic acid compound constituting the polyimide amide imide resin contains a compound derived from formula (IV)
[Chem 4]

[In formula (IV), R ²³ and R ²⁴ each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ²⁵ to R ³² each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ²⁵ to R ³² may be independently substituted by halogen atoms, and A independently represents -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -NR ^33- , R ³³ represents a C1-C12 hydrocarbon group which may be substituted by a halogen atom, m represents an integer of 1-4]
The structural unit of the compound represented.
[Effect of invention]

The optical film of the present invention has excellent bending resistance and excellent stability of optical characteristics at high temperature and high humidity.

The optical film of the present invention is made of polyamidoamide resin.

＜ Polyamide amide imide resin ＞
In this specification, the polyimide amide imine resin means a polymer containing both a repeating structural unit containing an amide imide group and a repeating structural unit containing an amide imide group. The polyamide amide imine resin is preferably a resin obtained by copolymerizing a carboxylic acid compound containing a dicarboxylic acid compound, a tetracarboxylic acid compound, and a tricarboxylic acid compound if necessary, and a diamine compound. Therefore, the polyamidimide resin of the present invention contains a structural unit derived from a dicarboxylic acid compound, a structural unit derived from a tetracarboxylic acid compound, and a structural unit derived from a tricarboxylic acid compound as necessary The structural unit of the carboxylic acid compound and the structural unit derived from the diamine compound. In addition, in this specification, the "structural unit derived from a compound" may be simply referred to as "unit". For example, the “structural unit of compound” derived from dicarboxylic acid is sometimes referred to as “unit” of dicarboxylic acid, and the “structural unit of compound” derived from tetracarboxylic acid is referred to as “unit” of tetracarboxylic acid, which is derived from di The amine "structural unit of the compound" is called the diamine "unit".

The structural unit derived from the dicarboxylic acid compound that constitutes the polyimide amide imine resin preferably contains a compound derived from the formula (I)
[Chemical 5]

[In formula (I), R ¹ and R ² each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ³ to R ⁶ each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ³ to R ⁶ may be independently substituted by halogen atoms]
The structural unit of the compound represented (sometimes referred to as the structural unit derived from the dicarboxylic acid compound (I)).

In addition, the structural unit derived from the tetracarboxylic acid compound constituting the polyimide amide imine resin preferably contains the formula (II)
[化 6]

[In formula (II), R ⁷ to R ¹⁴ each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ⁷ to R ¹⁴ may be Independently substituted by a halogen atom]
The structural unit of the compound represented (sometimes referred to as the structural unit derived from the tetracarboxylic acid compound (II)), the structural unit derived from the diamine compound constituting the polyimide amide imide resin preferably contains a formula derived from the formula (III)
[化 7]

[In formula (III), R ¹⁵ to R ²² each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ¹⁵ to R ²² may be Independently substituted by a halogen atom]
The structural unit of the compound represented (sometimes referred to as the structural unit derived from the diamine compound (III)). Here, in the polyamidoamide resin, the structural unit derived from the dicarboxylic acid compound (I) can be formed by the reaction (condensation) of the diamine compound (I) with the diamine compound. Group bonded to the structural unit derived from the diamine compound. The structural unit derived from the tetracarboxylic acid compound (II) can be bonded to the structural unit derived from the diamine compound through the amide imide group formed by the reaction (polycondensation) of the tetracarboxylic acid compound (II) and the diamine compound Knot. The structural unit derived from the diamine compound (III) can be formed by the amide group or iminium group formed by the reaction (polycondensation) of the diamine compound (III) with a dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid It is bonded to a structural unit derived from a dicarboxylic acid compound, a structural unit derived from a tricarboxylic acid compound, or a structural unit derived from a tetracarboxylic acid compound.

The dicarboxylic acid unit (preferably a structural unit derived from the dicarboxylic acid compound (I)) and the tetracarboxylic acid unit (preferably derived from the structure of the tetracarboxylic acid compound (II)) constituting the polyimide amide imine resin Unit) and a diamine unit (preferably a structural unit derived from the diamine compound (III)) may contain one kind or two or more kinds, respectively.

In formula (I), R ¹ and R ² are independently hydroxyl (-OH), methoxy (-OMe), ethoxy (-OEt), n-propoxy (-OPr), n-butoxy ( -OBu) or a chlorine atom (-Cl), preferably a chlorine atom (-Cl).

In formula (I), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, third butyl, n-pentyl, and 2-methyl- Butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, etc.

Examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, naphthyl, and biphenyl. The hydrogen atoms contained in R ³ to R ⁶ may each be independently substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In addition, examples of the C 6-12 aryl group which may be substituted with a halogen atom include chlorophenyl, dichlorophenyl, bromophenyl, dibromophenyl, chlorobromophenyl, chlorobiphenyl, Dichlorobiphenyl, bromophenyl, dibromophenyl, chloronaphthyl, dichloronaphthyl, bromonaphthyl, dibromonaphthyl, etc.

Among these, from the viewpoint of the bending resistance of the optical film, R ³ to R ⁶ are each independently preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group, particularly preferably a hydrogen atom . In addition, in the present invention, the bending resistance (bending resistance) refers to the characteristics that the optical film is less likely to cause scratches, cracks, white turbidity, etc. when the optical film is repeatedly bent and recovered continuously.

In a better embodiment of the present invention, the structural unit derived from the compound represented by formula (I) is derived from formula (I ')
[Chem 8]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the dicarboxylic acid compound (I ′)). If the polyimide amide imine resin contains a structural unit derived from a dicarboxylic acid compound (I ′), it is easy to improve the mechanical strength of the optical film, such as elastic modulus or bending resistance.

In formula (II), R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or 6 to 6 carbon atoms The aryl group of 12. Examples of the alkyl group having 1 to 6 carbon atoms include those exemplified as the alkyl group having 1 to 6 carbon atoms in R ³ to R ⁶ . In addition, examples of the aryl group having 6 to 12 carbon atoms include those exemplified as the aryl group having 6 to 12 carbon atoms in R ³ to R ⁶ . The hydrogen atoms contained in R ⁷ to R ¹⁴ may each be independently substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In addition, examples of the C 6-12 aryl group which may be substituted with a halogen atom include R ³ to R ⁶ exemplified as the C 6-12 aryl group which may be substituted with a halogen atom.

Among these, from the viewpoint of easily improving the bending resistance and transparency of the optical film, R ⁷ to R ¹⁴ are each independently preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group, More preferably, R ⁷ , R ⁸ , R ⁹ , R ¹² , R ¹³ , and R ¹⁴ are hydrogen atoms, and R ¹⁰ and R ¹¹ are hydrogen atoms, methyl groups, fluoro groups, chloro groups, or trifluoromethyl groups, particularly preferably R ¹⁰ and R ¹¹ are methyl or trifluoromethyl.

In a preferred embodiment of the present invention, the structural unit derived from the compound represented by formula (II) is derived from formula (II ')
[化 9]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the tetracarboxylic acid compound (II ')). If the polyimide amide imine resin contains a structural unit derived from a tetracarboxylic acid compound (II '), the bending resistance and transparency (for example, haze and total light transmittance) of the optical film can be improved. Furthermore, the skeleton containing fluorine element can improve the solubility of the polyamidoamide imide resin in the solvent, suppress the viscosity of the polyamidoamide imine varnish to be low, and facilitate the manufacture of optical films.

In formula (III), R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , and R ²² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 6 carbon atoms ~ 12 aryl groups. Examples of the alkyl group having 1 to 6 carbon atoms include those exemplified as the alkyl group having 1 to 6 carbon atoms in R ³ to R ⁶ . Examples of the aryl group having 6 to 12 carbon atoms include those exemplified as the aryl group having 6 to 12 carbon atoms in R ³ to R ⁶ . The hydrogen atoms contained in R ¹⁵ to R ²² may each be independently substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In addition, examples of the C 6-12 aryl group which may be substituted with a halogen atom include R ³ to R ⁶ exemplified as the C 6-12 aryl group which may be substituted with a halogen atom.

Among these, from the viewpoint of easily improving the transparency of the optical film, R ¹⁵ to R ²² are each independently preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group, more preferably R ¹⁵ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , and R ²² are hydrogen atoms, R ¹⁶ and R ²¹ are hydrogen atoms, methyl, fluoro, chloro or trifluoromethyl, particularly preferably R ¹⁶ and R ²¹ is methyl or trifluoromethyl.

In a preferred embodiment of the present invention, the structural unit derived from the compound represented by formula (III) is derived from formula (III ')
[化 10]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the diamine compound (III ')). If the polyimide amide imine resin contains structural units derived from the diamine compound (III '), the mechanical strength (eg, elastic modulus, bending resistance) and transparency of the optical film can be improved. Furthermore, the skeleton containing fluorine element can improve the solubility of the polyamidoamide imide resin in the solvent, suppress the viscosity of the polyamidoamide imine varnish to be low, and facilitate the manufacture of optical films.

From the viewpoint of easily improving the bending resistance and transparency of the optical film, the polyamidoamide resin contained in the optical film of the present invention preferably contains a single bond derived from two or more aromatic hydrocarbon rings with a single bond The structural unit of the aromatic dicarboxylic acid compound connected with the divalent group other than the aromatic group serves as a dicarboxylic acid unit. Examples of the aromatic hydrocarbon ring include monocyclic hydrocarbon rings such as benzene rings; polycyclic hydrocarbon rings such as condensed bicyclic hydrocarbon rings such as naphthalene, and polycyclic hydrocarbon rings such as bicyclic hydrocarbon rings such as biphenyl, and preferably benzene rings. Specifically, it is preferable to contain the formula (IV)
[化 11]

[In formula (IV), R ²³ and R ²⁴ each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ²⁵ to R ³² each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ²⁵ to R ³² may be independently substituted by halogen atoms, and A independently represents -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ , -S-, -CO- or- NR ^33- , R ³³ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom, and m represents an integer of 1 to 4]
The structural unit of the compound represented (sometimes referred to as the structural unit derived from the dicarboxylic acid compound (IV)).

In formula (IV), from the viewpoint of easily lowering the drying temperature and easily obtaining an optical film having good bending resistance, A independently represents -O-, -CH _2- , and -CH _2- CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -NR ^33- , it is easy From the viewpoint of obtaining an optical film excellent in bending resistance, it preferably represents -O-, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ or -S -, More preferably represents -O-, -CH _2- , -C (CH ₃ ) ₂ -or -SO _2- , and more preferably represents -O-. R ²³ and R ²⁴ independently represent a hydroxyl group, a methoxy group, an ethoxy group, a n-propoxy group, a n-butoxy group or a chlorine atom, R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ and R ³² each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group. Examples of the alkyl group having 1 to 6 carbon atoms include those exemplified as the alkyl group having 1 to 6 carbon atoms in R ³ to R ⁶ . Examples of the aryl group having 6 to 12 carbon atoms include those exemplified as the aryl group having 6 to 12 carbon atoms in R ³ to R ⁶ . The hydrogen atoms contained in R ²⁵ to R ³² may each be independently substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In addition, examples of the C 6-12 aryl group which may be substituted with a halogen atom include R ³ to R ⁶ exemplified as the C 6-12 aryl group which may be substituted with a halogen atom. R ³³ represents a C 1-12 hydrocarbon group which may be substituted by a halogen atom. Examples of the hydrocarbon group having 1 to 12 carbon atoms include those exemplified as alkyl groups having 1 to 6 carbon atoms for R ³ to R ⁶ or aryl groups having 6 to 12 carbon atoms.

In formula (IV), m represents an integer of 1 to 4. If m is within this range, it is easy to obtain an optical film having good bending resistance and elastic modulus. In addition, in formula (IV), m is preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1, if m is within this range, it is easy to further increase the elastic modulus.

Among these, from the viewpoint of easily improving the bending resistance of the optical film, R ²⁵ to R ^{32 are} preferably a hydrogen atom or a C 1-6 alkyl group, more preferably a hydrogen atom or a C 1 to 3 carbon atom The alkyl group is more preferably a hydrogen atom.

In a preferred embodiment of the present invention, the structural unit derived from the compound represented by formula (IV) is derived from formula (IV ')
[Chem 12]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the dicarboxylic acid compound (IV ')). If the polyimide amide imine resin contains the structural unit derived from the dicarboxylic acid compound (IV '), the bending resistance and transparency of the optical film can be improved. Furthermore, the skeleton containing fluorine element can improve the solubility of the polyamidoamide imide resin in the solvent, suppress the viscosity of the polyamidoamide imine varnish to be low, and facilitate the manufacture of optical films.

In a preferred aspect of the present invention, the polyamidoamide resin of the present invention includes a structural unit derived from a dicarboxylic acid compound, a structural unit derived from a tetracarboxylic acid compound, and a structure derived from a diamine compound Unit resin. Furthermore, in a more preferred aspect of the present invention, the polyamidoamide resin of the present invention includes a structural unit derived from a dicarboxylic acid compound (I), a structural unit derived from a tetracarboxylic acid compound (II), Resin derived from the structural unit of the diamine compound (III) and derived from the structural unit of the dicarboxylic acid compound (IV). In a more preferred aspect of the present invention, the polyamidoamide resin of the present invention includes a structural unit derived from a dicarboxylic acid compound (I '), a structural unit derived from a tetracarboxylic acid compound (II'), The resin derived from the structural unit of the diamine compound (III ') and the structural unit derived from the dicarboxylic acid compound (IV'). The optical film including the polyamidoamide resin having such a structural unit is advantageous in terms of bending resistance and transparency (especially maintaining transparency under high temperature and high humidity environment).

In one embodiment of the present invention, the polyimide amide imine resin may contain the structural unit derived from the dicarboxylic acid compound (I) and the dicarboxyl group exemplified above within the range of non-destructive various physical properties of the optical film. Structural units other than the structural unit of the acid compound (IV), the structural unit derived from the tetracarboxylic acid compound (II), and the structural unit derived from the diamine compound (III).

Examples of other structural units include structural units derived from the dicarboxylic acid compound (I) and structural units derived from the dicarboxylic acid compound other than the structural units derived from the dicarboxylic acid compound (IV), and derived from tetracarboxylic acid compounds. Other than the structural unit of the carboxylic acid compound (II), the structural unit derived from the tetracarboxylic acid compound, the structural unit derived from the tricarboxylic acid compound, and the structural unit derived from the diamine compound (III) are derived from the diamine Structural units of compounds, etc. In addition, the above-mentioned dicarboxylic acid compound represents a dicarboxylic acid or a dicarboxylic acid derivative (for example, dicarboxylic acid chloride or acid anhydride), and the above-mentioned tricarboxylic acid compound represents a tricarboxylic acid or a tricarboxylic acid derivative (for example, tricarboxylic acid (Acyl chloride or acid anhydride), the above-mentioned tetracarboxylic acid compound means a tetracarboxylic acid or a tetracarboxylic acid derivative (for example, tetracarboxylic acid chloride or acid anhydride).

Examples of other dicarboxylic acid units include those derived from formula (V)
[Chem 13]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the dicarboxylic acid compound (V)). As the dicarboxylic acid unit, one or two or more structural units derived from the dicarboxylic acid compound (V) may be contained. When two or more structural units are included, each structure derived from the dicarboxylic acid compound (V) In the unit, the type of Z is different.

In formula (V), Z represents formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (27) and formula (29) The non-adjacent two of the bonding bonds of the base are substituted with hydrogen atoms or a divalent chain hydrocarbon group with a carbon number of 6 or less. R ³⁴ and R ³⁵ are independently hydroxyl (-OH), methoxy (-OMe), ethoxy (-OEt), n-propoxy (-OPr), n-butoxy (-OBu) or chlorine atom (-Cl), preferably a chlorine atom (-Cl).

Specific examples of the dicarboxylic acid compound constituting the dicarboxylic acid unit include, for example, 4,4′-oxybisbenzoic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and 4,4′- Biphenyl dicarboxylic acid, 3,3'-biphenyl dicarboxylic acid, two benzoic acids with a single bond, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- Aromatic dicarboxylic acids and their derivatives (such as acetyl chloride and acid anhydrides) linked by phenylene-linked compounds; aliphatic dicarboxylic acids such as dicarboxylic acid compounds of chain hydrocarbons with a carbon number of 8 or less And their derivatives (such as acetyl chloride, ester) and so on. These dicarboxylic acid compounds can be used individually or in combination of 2 or more types. Among these, in order to achieve both the elastic modulus and bending resistance of the optical film, it is preferable to use the compound represented by the formula (I) in combination with the compound represented by the above formula (IV). As a specific example, it is preferable to use 4,4′-oxybis (benzoyl chloride) and terephthaloyl chloride together.

Examples of other tetracarboxylic acid units include those derived from formula (VI)
[化 14]

Structural unit of the compound represented (sometimes referred to as structural unit derived from tetracarboxylic acid compound (VI)), and derived from formula (VII)
[化 15]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the tetracarboxylic acid compound (VII)). Here, in the polyamidoamide resin of the present invention, the structural unit derived from the tetracarboxylic acid compound represented by formula (VI) and the structural unit derived from the diamine compound may be formed on both sides of Y via The amide imino group is bonded. A structural unit of the tetracarboxylic acid compound and, from the formula (VII) may be represented by the structural unit derived from a diamine compound formed on one side of the Y via the imino acyl of ¹ and formed on the other side of the Y ¹ The amide group is bonded. As the tetracarboxylic acid unit, one or two or more structural units derived from a tetracarboxylic acid compound (VI) and a structural unit derived from a tetracarboxylic acid compound (VII) may be contained, respectively. When two or more structural units derived from a tetracarboxylic acid compound (VI) and a structural unit derived from a tetracarboxylic acid compound (VII) are contained, more than two types of structural units derived from a tetracarboxylic acid compound (VI) In the structural unit, the type of Y is different, and in the two or more structural units derived from the tetracarboxylic acid compound (VII), the type of Y ¹ is different.

In formula (VI), Y is a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms. The above-mentioned organic group is an organic group in which a hydrogen atom in an organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with a halogen atom. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. As Y, it represents: the bases represented by formula (20), formula (21), formula (23), formula (24), formula (25) and formula (27), formula (28), formula (29); The hydrogen atom in the group represented by the equation is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; or a tetravalent chain hydrocarbon group with a carbon number of 6 or less. Furthermore, in formula (VII), Y ¹ is a tetravalent organic group, preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with a halogen atom, which represents: formula (20), The bases represented by formula (21), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or formula (29); A group in which the hydrogen atom in the group is substituted with a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group; or a tetravalent chain hydrocarbon group with a carbon number of 6 or less. From the viewpoint of easily reducing the yellowness of the optical film, in formula (VI) or formula (VII), Y or Y ^{1 is} preferably: formula (20), formula (21), formula (22), formula ( 23), the formula (24), the formula (25), the formula (26) or the formula (27) represents the group; the hydrogen atom in the group represented by the formula represents the methyl, fluoro, chloro or trifluoro Methyl substituted group. In addition, R ³⁶ and R ³⁷ are independently hydroxyl (-OH), methoxy (-OMe), ethoxy (-OEt), n-propoxy (-OPr), n-butoxy (-OBu) or The chlorine atom (-Cl) is preferably a chlorine atom (-Cl).
[Chem 16]

In formula (20) to formula (29),
﹡ Means bonding key,
W ¹ represents a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) ₂ -,- _{Ar -, - SO 2 -,} - CO -, - O-Ar-O -, - Ar-O-Ar -, - Ar-CH 2 -Ar -, - Ar-C (CH 3) 2 -Ar- , or -Ar-SO ₂ -Ar-. Ar represents a C 6-20 arylene group in which a hydrogen atom can be substituted with a fluorine atom, and specific examples include phenylene group. From the viewpoint of easily improving the elastic modulus of the obtained optical film, in formula (VI) or formula (VII), Y or Y ^{1 is} preferably formula (26), formula (28), or formula (29), respectively ) Represents the basis. From the viewpoint of easily suppressing the yellowness of the optical film, W ¹ is preferably a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, respectively. , -C (CH ₃ ) ₂ -or -C (CF ₃ ) _2- , more preferably single bond, -O-, -CH _2- , -C (CH ₃ ) ₂ -or -C (CF ₃ ) ₂ -, And more preferably -C (CH ₃ ) ₂ -or -C (CF ₃ ) _2- .

Examples of the tetracarboxylic acid compound constituting the tetracarboxylic acid unit include aromatic tetracarboxylic acid compounds and their anhydrides, preferably aromatic carboxylic acid compounds such as dianhydrides, and aliphatic tetracarboxylic acid compounds and their anhydrides, preferably Aliphatic tetracarboxylic acid compounds such as dianhydride and the like. The tetracarboxylic acid compound may be a derivative of a tetracarboxylic acid compound such as acetyl chloride in addition to acid anhydride, and these may be used alone or in combination of two or more kinds.

Specific examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydride, monocyclic aromatic tetracarboxylic dianhydride, and condensed polycyclic aromatic tetracarboxylic dianhydride. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include: 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride , 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-bi Pyromellitic dianhydride, 3,3 ', 4,4'-diphenyl sulfone tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2- Bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4 '-(hexafluoroisopropylidene) Diphthalic dianhydride (sometimes also expressed as 6FDA), 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ) Ethane dianhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic dianhydride and 4,4' -(M-phenylenedioxy) diphthalic dianhydride. In addition, examples of monocyclic aromatic tetracarboxylic dianhydride include 1,2,4,5-benzenetetracarboxylic dianhydride, and examples of condensed polycyclic aromatic tetracarboxylic dianhydride include 2,3, 6,7-Naphthalenetetracarboxylic dianhydride.
Among these, preferred examples include: 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,2', 3 , 3'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyl ash tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-di Carboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride , 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4 -Dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic dianhydride and 4,4'-(m-phenylenedioxy) diphthalic dianhydride , More preferably: 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyl Tetracarboxylic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride, bis (3,4-dicarboxyphenyl) methanedi Anhydride and 4,4 '-(p-phenylenedioxy) diphthalic dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or non-cyclic aliphatic tetracarboxylic dianhydride. The cycloaliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include: 1,2,4,5-cyclohexanetetracarboxylic dianhydride, Cycloalkane tetracarboxylic dianhydride such as 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, bicyclo [2.2.2] octane- 7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl 3,3'-4,4'-tetracarboxylic dianhydride and positional isomers of these. These can be used alone or in combination of two or more. Specific examples of the non-cyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentane tetracarboxylic dianhydride, etc. , These can be used alone or in combination of two or more. In addition, cyclic aliphatic tetracarboxylic dianhydride and non-cyclic aliphatic tetracarboxylic dianhydride may be used in combination.

Among the tetracarboxylic acid compounds, from the viewpoint of easily improving the elastic modulus, bending resistance, and optical properties of the optical film, the above-mentioned alicyclic tetracarboxylic dianhydride or non-condensed polycyclic aromatic tetra Carboxylic dianhydride. As a specific example, 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4 'are preferred -Biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenyl sulfone tetracarboxylic dianhydride, 2,2 -Bis (3,4-dicarboxyphenyl) propane dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride, and mixtures thereof, more preferably 3,3' , 4,4'-biphenyltetracarboxylic dianhydride and 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride, and mixtures of these, further preferably 4,4'- (Hexafluoroisopropylidene) diphthalic dianhydride.

Examples of other tricarboxylic acid units include those derived from formula (VIII)
[化 17]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the tricarboxylic acid compound (VIII)). The tricarboxylic acid compound means a tricarboxylic acid or a tricarboxylic acid derivative. Examples of the tricarboxylic acid derivative include trichlorocarboxylic acid chloride and ester. In the case where the polyimide amide imine resin of the present invention contains a structural unit derived from the tricarboxylic acid compound (VIII), the structural unit derived from the tricarboxylic acid compound (VIII) may be the same as the structural unit derived from the diamine compound It is bonded via an amide imide group or amide group formed on both sides of Y ² . As the tricarboxylic acid unit, one kind or two or more kinds of tricarboxylic acid units (VIII) may be contained. When two or more kinds of tricarboxylic acid units are contained, the type of Y ² is different in each tricarboxylic acid unit (VIII). In addition, R ³⁸ is -OH, -OMe, -OEt, -OPr, -OBu, or -Cl, preferably -Cl. Y ² is a trivalent organic group, preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a hydrocarbon group substituted with a halogen atom. Y ² represents formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28), or formula ( 29) Any one of the bonding bonds of the represented group is substituted with a hydrogen atom group or a trivalent C 6 or less chain hydrocarbon group.

When the polyimide amide imine resin of the present invention contains a tricarboxylic acid unit, examples of the tricarboxylic acid compound constituting the tricarboxylic acid unit include aromatic tricarboxylic acid, aliphatic tricarboxylic acid, and their derivatives Substances (for example, acetyl chloride, acid anhydride, etc.), and specific examples thereof include: 1,2,4-benzenetricarboxylic acid anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; o-benzene Dicarboxylic anhydride and benzoic acid are connected by a single bond, -O-, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ -or phenylene . These tricarboxylic acid compounds can be used individually or in combination of 2 or more types.

Examples of other diamine units include those derived from formula (IX)
[Chemical 18]

The structural unit of the compound represented (sometimes referred to as the structural unit derived from the diamine compound (IX)). Here, in the polyamidoamide resin of the present invention, the structural unit derived from the diamine compound (IX) may be bonded to the structural unit derived from the dicarboxylic acid via the amide group formed on both sides of X It can be bonded to the structural unit derived from the tetracarboxylic acid compound through the amide imide group or amide group formed on both sides of X, and can be bonded to the structural unit derived from the tricarboxylic acid compound through the two formed in X The amide imide group or amide group on the side is bonded. In addition, as the diamine unit, one or two or more structural units derived from the diamine compound (IX) may be contained. When two or more structural units are included, each structural unit derived from the diamine compound (IX) In, the type of X is different. X represents a divalent organic group, and preferably represents a divalent organic group having 4 to 40 carbon atoms. The above-mentioned organic group may have a hydrogen atom in the organic group substituted with a hydrocarbon group or a hydrocarbon group substituted with a halogen atom. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. As X, it represents: the base represented by formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16) or formula (17); The group in which the hydrogen atom in the group represented by the equation is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; or a chain hydrocarbon group having a carbon number of 6 or less.

[Chem 19]

In formula (10) to formula (17), ﹡ represents a bonding bond,
V ^1, V ² and V ³ each independently represent a single bond, -O -, - S -, - CH 2 -, - CH 2 -CH 2 -, - CH (CH 3) -, - C (CH 3) _2- , -C (CF ₃ ) _2- , -SO _2- , or -CO-.
As an example, V ¹ and V ³ are single bonds, -O- or -S-, and V ² is -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , or -SO _2- . The bonding positions of V ¹ and V ² to each ring and the bonding positions of V ² and V ³ to each ring are preferably meta or para with respect to each ring, more preferably para. In addition, from the viewpoint of easily improving the elastic modulus of the optical film containing the polyamidoamide resin, V ¹ , V ² and V ³ are each independently preferably a single bond, -O- or -S -, More preferably single bond or -O-.

Examples of the diamine compound constituting the diamine unit include aliphatic diamines, aromatic diamines, and mixtures of these. Furthermore, in the present embodiment, the term "aromatic diamine" means a diamine in which an amine group is directly bonded to an aromatic ring, and may contain an aliphatic group or other substituents in a part of its structure. The aromatic ring may be a single ring or a condensed ring, and examples include a benzene ring, a naphthalene ring, an anthracene ring, and a fused ring, but it is not limited thereto. Among these, a benzene ring is preferred. The "aliphatic diamine" means a diamine in which an amine group is directly bonded to an aliphatic group, and may contain an aromatic ring or other substituents in a part of its structure.

Specific examples of the aliphatic diamine include non-cyclic aliphatic diamines such as hexamethylenediamine; 1,3-bis (aminomethyl) cyclohexane, and 1,4-bis (amino Cycloaliphatic diamines such as methyl) cyclohexane, noranediamine, 4,4'-diaminodicyclohexylmethane, etc. These can be used alone or in combination of two or more.

Specific examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, and 1,5-diaminonaphthalene , 2,6-diaminonaphthalene and other aromatic diamines with one aromatic ring; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4 '-Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4' -Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy Group) benzene, 4,4'-diaminodiphenyl sulfone, bis [4- (4-aminophenoxy) phenyl] benzene, bis [4- (3-aminophenoxy) phenyl ] 碸, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2 '-Dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (sometimes also expressed as TFMB), 4,4'-bis (4-amine Phenoxy) biphenyl, 9,9-bis (4-aminophenyl) stilbene, 9,9-bis (4-amino-3-methylphenyl) stilbene, 9,9-bis (4 -Amino-3-chlorophenyl) stilbene, 9,9-bis (4-amino-3-fluorophenyl) stilbene, etc. with more than 2 aromatic rings Fragrant aromatic diamine. These can be used alone or in combination of two or more.

As the aromatic diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3 are preferred '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene , Bis [4- (4-aminophenoxy) phenyl] satin, bis [4- (3-aminophenoxy) phenyl] satin, 2,2-bis [4- (4-amino Phenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2'-dimethylbenzidine, 2,2'-bis (tris Fluoromethyl) -4,4'-diaminobiphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylbenzene, 1,4-bis (4-aminophenoxy Group) benzene, bis [4- (4-aminophenoxy) phenyl] benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-di Methylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-bis (4-aminophenoxy) biphenyl. These can be used alone or in combination of two or more.

Among the above-mentioned diamine compounds, from the viewpoint of easily improving the mechanical strength (eg, bending resistance, elastic modulus) of the optical film, and easily improving the optical properties, such as reducing haze, it is preferable to use One or more of the group consisting of aromatic diamine with benzene structure. More preferably, it is selected from 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-bis (4- (Aminophenoxy) biphenyl and 4,4'-diaminodiphenyl ether in one or more groups, and more preferably 2,2'-bis (trifluoromethyl) -4, 4'-diaminobiphenyl.

The content of dicarboxylic acid units contained in the carboxylic acid units constituting the polyamidoamide resin is preferably 20 mol% or more relative to the total number of moles of all structural units of the carboxylic acid units, and more preferably 30 More than 40 mol%, more preferably more than 40 mol%, particularly preferably more than 50 mol%, most preferably more than 60 mol%, and most preferably less than 90 mol%, more preferably 85 mol% Below, further preferably 80 mol% or less. If the content of the dicarboxylic acid unit is equal to or higher than the above lower limit, the mechanical strength (eg, elastic modulus) of the optical film is easily improved by the hydrogen bond between the amide bonds derived from the dicarboxylic acid unit. Furthermore, if the content of the dicarboxylic acid unit is below the above upper limit, the following polyamidoamide can be suppressed by suppressing the thickening caused by the hydrogen bond between the amide bonds derived from the dicarboxylic acid unit The viscosity of the amine varnish can make the processing of optical films easier.

The content of the tetracarboxylic acid unit contained in the carboxylic acid unit constituting the polyamidoamide resin relative to the total number of moles of the carboxylic acid unit is preferably 10 mol% or more, and more preferably 20 mol% or more , And preferably 60 mol% or less, more preferably 50 mol% or less, and further preferably 40 mol% or less. If the content of the tetracarboxylic acid unit is equal to or lower than the above upper limit, the mechanical strength (eg, elastic modulus) tends to be improved. If the content of the tetracarboxylic acid unit is equal to or higher than the above lower limit, there is a tendency that the solubility in the solvent or the optical characteristics (such as haze or yellowness) can be improved.

In the carboxylic acid unit contained in the polyamidoamide resin, the content of the dicarboxylic acid unit is preferably 1 mole or more relative to the tetracarboxylic acid unit, preferably 0.1 mole or more, and more preferably 1 mole or more, Furthermore, it is preferably 2 moles or more, and preferably 5 moles or less, more preferably 4 moles or less, and still more preferably 3 moles or less. If the content of the dicarboxylic acid unit is more than the above lower limit, the optical film tends to increase in mechanical strength (e.g., elastic modulus), and if it is below the above upper limit, it can be suppressed The viscosity increase caused by the hydrogen bond between the amine bonds reduces the viscosity of the polyamidoamide imide varnish, making the manufacture of optical films easier.

The content (R _(I) ) of the structural unit derived from the compound represented by the formula (I) (structural unit derived from the dicarboxylic acid compound _(I) ) is relative to the total structural unit constituting the polyimide amide imide resin The total mole number is preferably greater than 0 mole%, more preferably 5 mole% or more, and further preferably 10 mole% or more, particularly preferably 15 mole% or more, and most preferably 20 mole% or more In particular, it is 25 mol% or more, and preferably 40 mol% or less, and more preferably 35 mol% or less. Moreover, the content of the structural unit derived from the compound represented by the above formula (I) (structural unit derived from the dicarboxylic acid compound (I)) relative to the total moles of the carboxylic acid units constituting the polyimide amide imide resin The number is preferably greater than 0 mol%, more preferably 10 mol% or more, and further preferably 20 mol% or more, particularly preferably 30 mol% or more, and most preferably 40 mol% or more, especially 50 mol% or more, and preferably 80 mol% or less, more preferably 70 mol% or less. If the content of the structural unit derived from the dicarboxylic acid compound (I) is at least the above lower limit, the rigidity of the structure derived from the structural unit derived from the dicarboxylic acid compound (I) easily improves the mechanical properties of the optical film If the strength (for example, elastic modulus) is below the above upper limit, it is possible to suppress the thickening caused by hydrogen bonding between amide bonds derived from the structural unit derived from the dicarboxylic acid compound (I) And to suppress the viscosity of the following polyamide amide imine varnish, can make the processing of optical film easy. Furthermore, in this specification, the content (mol%) of the structural units derived from the compound represented by the above formula (I) relative to the total number of moles of all the structural units constituting the polyamidoamide resin is referred to as R _(I) .

The content of the structural unit derived from the compound represented by the formula (II) (the structural unit derived from the tetracarboxylic acid compound (II)) is less than the total moles of all the structural units constituting the polyimide amide imide resin. It is preferably 5 mol% or more, more preferably 10 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, and further preferably 20 mol% or less. Moreover, the content of the structural unit derived from the compound represented by the formula (II) (the structural unit derived from the tetracarboxylic acid compound (II)) relative to the total number of moles of the carboxylic acid unit constituting the polyamidoamide resin It is preferably 10 mol% or more, more preferably 20 mol% or more, and preferably 60 mol% or less, more preferably 50 mol% or less, and further preferably 40 mol% or less. If the content of the structural unit derived from the tetracarboxylic acid compound (II) is above the lower limit, the mechanical strength (eg, elastic modulus) of the optical film is easily improved, and if it is below the above upper limit, it is easy to increase Solubility to solvents or optical properties (such as haze or yellowness).

The content of the structural unit derived from the compound represented by the formula (III) (the structural unit derived from the diamine compound (III)) is preferably relative to the total moles of all the structural units constituting the polyimide amide imine resin 20 mol% or more, more preferably 30 mol% or more, and further preferably 40 mol% or more, particularly preferably 45 mol% or more, and preferably 80 mol% or more, more preferably 70 mol% Ear% or less, more preferably 60 mole% or less, particularly preferably 55 mole% or less. Moreover, the content of the structural unit derived from the compound represented by the formula (III) (structural unit derived from the diamine compound (III)) relative to the total moles of the diamine unit constituting the polyimide amide imine resin, It is preferably 30 mol% or more, more preferably 50 mol% or more, and further preferably 70 mol% or more, and preferably 100 mol% or less. If the content of the structural unit derived from the diamine compound (III) is in the above range, the bending resistance and transparency of the optical film can be easily improved, and further the solubility of the polyamidoamide imine resin in the solvent can be further improved, and the poly The viscosity of the amide imide varnish is suppressed to be lower, and it is easy to manufacture optical films.

The content of the structural unit derived from the compound represented by formula (IV) (the structural unit derived from the dicarboxylic acid compound (IV)) relative to the total moles of all the structural units constituting the polyimide amide imine resin is less than It is preferably 1.5 mol% or more, more preferably 2.5 mol% or more, and further preferably 3.5 mol% or more, particularly preferably 5 mol% or more, and preferably 35 mol% or less, more preferably 30 Moore% below. Moreover, the content of the structural unit derived from the dicarboxylic acid compound (IV) is preferably 3 mol% or more, and more preferably 5 mol relative to the total number of mols of carboxylic acid units constituting the polyamidoamide resin. Ear% or more, more preferably 7 mole% or more, particularly preferably 10 mole% or more, and preferably 70 mole% or less, more preferably 65 mole% or less, still more preferably 60 mole% the following. If the content of the structural unit derived from the dicarboxylic acid compound (IV) is above the lower limit, the bending resistance is easily improved, and if it is below the above upper limit, it is possible to suppress the source derived from the dicarboxylic acid The viscosity increase of the hydrogen bond between the amide bond of the structural unit of the acid compound (IV), and the inhibition of the viscosity of the following polyamide amide imine varnish can facilitate the processing of the optical film.

In a preferred embodiment of the present invention, the polyimide amide imine resin may contain halogen atoms as described above. Specific examples of fluorine-containing substituents include fluorine groups and trifluoromethyl groups. By containing a halogen atom in the polyamidoimide resin, the transparency of the optical film made of the polyamidoimide resin is easily improved. From the viewpoint of transparency of the optical film, the halogen atom is preferably a fluorine atom.

From the viewpoint of easily improving the transparency of the optical film, the content of halogen atoms in the polyamidoamide resin is preferably 1 to 40% by mass relative to the mass of the polyamidoamide resin, and more preferably It is 3 to 35% by mass, and more preferably 5 to 32% by mass.

As described above, the polyimide amide imine resin of the present invention is carried out by using the carboxylic acid compound containing the above-mentioned dicarboxylic acid compound, the above-mentioned tetracarboxylic acid compound, and optionally the above-mentioned tricarboxylic acid compound and the above-mentioned diamine compound Manufactured by reaction. Particularly preferred are compounds represented by formula (I), compounds represented by formula (II), compounds represented by formula (III), compounds represented by formula (IV) as needed, other carboxylic acids, and others It is produced by the reaction of diamine, for example, polycondensation. In one embodiment of the present invention, an amide imidization catalyst may also be present in the synthesis of the amide imide resin. Examples of the imidate catalyst include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, and N-butylpyrrolidine. , N-butylpiperidine, and N-propyl hexahydroazepine and other alicyclic amines (monocyclic); azabicyclo [2.2.1] heptane, azabicyclo [3.2.1] octane Alicyclic amines (polycyclic) such as azabicyclo [2.2.2] octane and azabicyclo [3.2.2] nonane; and pyridine, 2-methylpyridine, 3-methylpyridine, 4- Picoline, 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine, 2,4,6-trimethylpyridine, 3,4-cyclopentenepyridine , 5,6,7,8-tetrahydroisoquinoline, and isoquinoline and other aromatic amines.

In the production of polyimide amide imine resin, the reaction temperature is not particularly limited, for example, 50 to 350 ° C. The reaction time is also not particularly limited, and is, for example, about 30 minutes to 10 hours. If necessary, the reaction can be carried out in an inert environment or under reduced pressure. In addition, the reaction can be carried out in a solvent. Examples of the solvent include the following solvents used for preparing polyamidoamide imine varnish.

The weight average molecular weight in terms of standard polystyrene of polyamidoamide resin is preferably 210,000 or more, more preferably 300,000 or more, further preferably 350,000 or more, and preferably 750,000 or less, more preferably 600,000 The following is further preferably 500,000 or less. If the weight average molecular weight of the polyimide amide imide resin is above the lower limit, the bending resistance of the optical film containing the polyimide amide imide resin can be improved. In addition, if the weight average molecular weight of the polyamidoimide resin is below the upper limit, the viscosity of the polyamidoimide varnish can be suppressed to be low, and the optical film can be easily extended, so the processability Become good. In addition, in this specification, the weight average molecular weight can be measured by, for example, GPC (Gel Permeation Chromatography), and can be obtained by standard polystyrene conversion, and specifically, it can be described in Examples. Method.

In the optical film, the content of the polyamidimide resin relative to the mass of the optical film is preferably 30 to 99% by mass, more preferably 35 to 95% by mass, and further preferably 40 to 90% by mass, especially It is preferably 50 to 90% by mass. If the content of the polyimide amide imine resin is within the above range, it is easy to obtain an optical film excellent in bending resistance and transparency.

More specifically, the polyamidoamide resin of a preferred embodiment of the present invention has a repeating structural unit represented by formula (30) and a repeating structural unit represented by formula (33). Furthermore, the polyimide amide imine resin according to the preferred embodiment of the present invention may also contain formula (31) and formula (32) within the range of various properties of the polyimide amide imide-based polymer film obtained without damaging Any one or more of the repeating structural units represented by any one. In addition, the polyamidoamide resin may contain two or more types of repeating structural units represented by formula (30), formula (31), formula (32), and formula (33), respectively. The repeating structural unit represented by formula (33) is a structural unit formed by the reaction of a dicarboxylic acid compound and a diamine compound, and represents the structural unit derived from the dicarboxylic acid compound together with the structural unit derived from the diamine compound The structural unit. The repeating structural unit represented by formula (30) is a structural unit formed by the reaction of a tetracarboxylic acid compound and a diamine compound, and represents the structural unit derived from the tetracarboxylic acid compound together with the structural unit derived from the diamine compound The structural unit. The repeating structural unit represented by formula (32) is a structural unit formed by the reaction of a tricarboxylic acid compound and a diamine compound, and represents the structural unit derived from the tricarboxylic acid compound together with the structural unit derived from the diamine compound The structural unit. The repeating structural unit represented by formula (31) is a structural unit formed by the reaction of a tetracarboxylic acid compound and a diamine compound, and represents the structural unit derived from the tetracarboxylic acid compound together with the structural unit derived from the diamine compound The structural unit.

[化 20]

In formula (30) to formula (33), K ¹ and K ³ represent formula (b), Y in formula (VI) or Y ¹ in formula (VII), and K ² represents formula (a) and formula ( d), or Z and K ⁴ in formula (V) represent Y ² in formula (VIII), and L ¹ to L ⁴ represent X in formula (c) or formula (IX), respectively.

[化 21]

^{6 3} ~ R the same as R (a) in the formula ³ ~ R as in the formula (I) R ^6, same as in the formula (b) R ⁷ ~ R ¹⁴ in the formula (II), the R ⁷ ~ R ^14, the same as the R R (c) of the formula ¹⁵ ~ R ²² in the formula (III) ¹⁵ ~ R ^22, the same as the in the formula (d) R ²⁵ ~ R ³² in the formula ^{(IV) R 25 ~ R 32} , ﹡ Means bonding key.

<Silica dioxide particles>
The optical film of the present invention may contain silicon dioxide particles. The average primary particle diameter of the silicon dioxide particles is preferably 10 nm or more, more preferably 15 nm or more, further preferably 20 nm or more, and preferably 100 nm or less, more preferably 80 nm or less, and more preferably Below 60 nm, particularly preferably below 40 nm. If the average primary particle diameter of the silica particles is within the above range, the aggregation of the silica particles can be suppressed, the transparency of the optical film can be improved, and the bending resistance can also be improved. In addition, if the average primary particle size of the silica particles is below the upper limit, even if the thickness of the optical film is relatively thick, the haze value is easily reduced. In particular, if the average primary particle size of the silicon dioxide particles is preferably 80 nm or less, and more preferably 60 nm or less, for example, even if the thickness of the optical film is 30 μm or more, it can show a lower haze value, more The haze value is preferably 1.0% or less, and more preferably 0.8% or less (corresponding to Hz _b ). In addition, in the present invention, the average primary particle size can be measured by the BET (Brunauer-Emmett-Teller, Buert) method.

<Optical film>
The optical film of the present invention contains the above-mentioned polyamidoamide resin and satisfies formula (1)
ΔHz ＜ 0.5 (1)
[In formula (1), ΔHz represents Hz _a- Hz _b , Hz _a represents _a mandrel test that bends once at a bending radius of 1 mm and returns to a planar shape at room temperature (according to JIS K 5600-5-1: The haze (%) of the optical film after 1999), Hz _b represents the haze (%) of the optical film before the mandrel test]
Relationship. Since the optical film of the present invention satisfies the relationship of formula (1), it has excellent bending resistance and excellent stability of optical characteristics at high temperature and high humidity. In addition, the optical film of the present invention has low haze and the like, and is excellent in transparency. That is, even if the operation of continuously folding and recovering the optical film of the present invention is repeated, the optical film is less likely to cause scratches, cracks, white turbidity, etc., and excellent optical characteristics such as transparency can be maintained. Moreover, even if the optical film is stored in a folded state under high temperature and high humidity, such as an environment of 85 ° C and 85% relative humidity, the optical film is less likely to cause scratches, cracks, white turbidity, etc., and transparency can be maintained Excellent optical properties. Therefore, the optical film of the present invention can be used as a component of an image display device, especially a front panel (window film) of a flexible display. For use in the front panel (window film) of a flexible display, from the viewpoint of durability during repeated use, the above-mentioned ΔHz 'before and after storage for 24 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% should preferably not reach 0.4 , Preferably 0.3 or less, and more preferably 0.2 or less. In addition, ΔHz 'can be measured and calculated by the method described in the examples.

The front panel has the function of protecting the image display element in the flexible display. Examples of image display devices include wearable devices such as TVs, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, indicators, bulletin boards, clocks, and smart watches. Examples of flexible displays include image display devices with flexible characteristics, such as TVs, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, indicators, bulletin boards, and clocks. , And wearable devices.

In formula (1), ΔHz represents Hz _a- Hz _b , Hz _a represents the haze of the optical film after the mandrel test that is restored immediately after bending once at a bending radius of 1 mm in an environment of room temperature and atmosphere (%). In more detail, ΔHz can be measured and calculated by the method described in the examples. Hz _b represents the haze (%) of the optical film before the mandrel test. ΔHz represents the amount of change in the haze of the optical film before and after the mandrel test (bending resistance test). The smaller the value, the higher the stability of the optical characteristics under bending. In addition, by appropriately adjusting the composition of the optical film, for example, the type or composition ratio of the repeating structure of the polyimide amide imide resin forming the optical film, and additives such as silicon dioxide particles or ultraviolet absorbers contained in the optical film The type or content, etc., the thickness of the optical film, or the manufacturing conditions of the optical film, such as the type of varnish solvent, drying temperature, drying time, etc., can be adjusted within the range of formula (1). In particular, if silica particles having an average primary particle diameter of not more than the above upper limit are used, the transparency becomes good, so it is easy to adjust to the range of formula (1).

In formula (1), Hz _b is usually preferably 20.0% or less, more preferably 2.0% or less, further preferably 1.0% or less, and particularly preferably 0.8% or less. If it is within the above range, the optical film can have good transparency, and when used in the case of a front panel of an image display device, it can contribute to higher visibility. In addition, ΔHz is less than 0.5%, more preferably 0.4% or less, further preferably 0.3% or less, and still more preferably 0.1% or less. If ΔHz is in the above range, the optical film has better bending resistance, and even at high temperature and high humidity, the optical characteristics such as transparency can be effectively maintained.

Moreover, the optical film of the present invention preferably contains the above-mentioned silicon dioxide particles, and preferably satisfies the relationship of formula (2):
0 ＜ R _Si ≦ 32 ＋ 2/3 × R _(I) (2)
[In formula (2), R _Si represents the content (mass%) of _silicon dioxide particles relative to the mass of the optical film, and R _(I) represents the structural unit derived from the compound represented by formula (I) relative to the constituent polyacrylamide The content of the total number of moles of all structural units of the amide imine resin (mol%)].

In formula (2), R _{Si is} preferably 5 mass% or more, more preferably 10 mass% or more, and further preferably 15 mass% or more, and preferably less than 60 mass%, more preferably 50 mass% or less . If the content of silica particles is above the above lower limit, the elastic modulus or bending resistance of the optical film can be further improved, and if the content of silica particles is below the above upper limit, for example, fogging can be reduced Degree to further improve transparency. Moreover, in one embodiment, even if the content of the silicon dioxide particles is relatively large, the optical film of the present invention can suppress the aggregation of the silicon dioxide particles, ensure good transparency, optical characteristics at high temperature and high humidity Since the stability is excellent and good bending resistance can also be obtained, R _Si may be 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, and 50 parts by mass or more.

The optical film of the present invention may further contain an ultraviolet absorber. Examples of the ultraviolet absorber include tri-derivatives (tri-based ultraviolet absorbers) such as benzotriazole derivatives (benzotriazole-based ultraviolet absorbers) and 1,3,5-triphenyl tri-derivatives, At least one kind selected from the group consisting of benzophenone derivatives (benzophenone-based ultraviolet absorbers) and salicylate derivatives (salicylate-based ultraviolet absorbers) . In terms of having a good ultraviolet absorption capability, it is preferable to use at least one selected from the group consisting of benzotriazole-based ultraviolet absorbers and three-series ultraviolet absorbers, more preferably a benzotriazole-based UV absorber.

Specific examples of the benzotriazole-based ultraviolet absorber include compounds represented by formula (A), and these may be used alone or in combination of two or more. Specific examples of the compound represented by formula (A) include: Sumitomo Chemical Co., Ltd. trade name: Sumisorb (registered trademark) 200 (2- (2-hydroxy-5-methylphenyl) benzotriazine Azole), Sumisorb 300 (2- (3-third butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole), Sumisorb 340 (2- (2-hydroxy-5- Trioctylphenyl) benzotriazole), Sumisorb 350 (2- (2-hydroxy3,5-di-third-pentylphenyl) benzotriazole).

[化 22]

In formula (A), T is a hydrogen atom, a fluorine atom, a chlorine atom, a C 1-5 alkyl group or a C 1-5 alkoxy group, and R ³⁹ and R ⁴⁰ are each independently a hydrogen atom or a carbon number 1 A hydrocarbon group of ~ 20, at least one of R ³⁹ or R ⁴⁰ is a hydrocarbon group having 1 to 20 carbon atoms.

Examples of the alkyl group having 1 to 5 carbon atoms in T include methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, third butyl, n-pentyl, and 2- Methyl-butyl, 3-methylbutyl, 2-ethyl-propyl, etc.
Examples of the alkoxy group having 1 to 5 carbon atoms in T include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, second butoxy, and third butoxy Group, n-pentyloxy, 2-methyl-butoxy, 3-methylbutoxy, 2-ethyl-propoxy, etc.
T is preferably a hydrogen atom, a fluorine atom, a chlorine atom or a methyl group, and more preferably a hydrogen atom, a fluorine atom or a chlorine atom.

R ³⁹ and R ⁴⁰ are each a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and at least one of R ³⁹ and R ⁴⁰ is a hydrocarbon group. When R ³⁹ and R ⁴⁰ are each a hydrocarbon group, it is preferably a hydrocarbon group having 1 to 12 carbon atoms, and more preferably a hydrocarbon group having 1 to 8 carbon atoms. Specifically, a methyl group, a third butyl group, a third pentyl group, and a third octyl group can be exemplified.

In the optical film, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, more preferably 1 to 8 parts by mass relative to 100 parts by mass of the total mass of the polyamidoamide resin and the silica particles. It is preferably 3 to 7 parts by mass. If the content of the ultraviolet absorber is more than the above lower limit, the ultraviolet absorbability can be improved. If the content of the ultraviolet absorber is less than the above upper limit, the decomposition of the ultraviolet absorber due to heat during the manufacture of the optical film can be suppressed, and the transparency of the optical film can be easily improved.

The optical film of the present invention may contain additives other than the above-mentioned polyamidoamide resin, the above-mentioned silica particles, and the above-mentioned ultraviolet absorber. Examples of other additives include resins other than polyamidoamide resins, antioxidants, mold release agents, stabilizers, coloring agents such as bluing agents, flame retardants, lubricants, and leveling agents. Other additives may be used alone or in combination of two or more. When the optical film contains an additive, the content of the additive relative to the mass of the optical film is preferably 0.01 to 20% by mass, and more preferably 0.1 to 10% by mass.

The other resins are not particularly limited, and include conventional resins such as polyolefin resins, cellulose resins, polyester resins, polycarbonate resins, (meth) acrylic resins, and polystyrene resins. , Polyether ether ketone-based resins, poly lanthanide-based resins, polyimide-based resins, etc. Other resins can be used alone or in combination of two or more.

The thickness of the optical film is appropriately adjusted depending on the application, and is usually 10 to 200 μm, preferably 20 to 100 μm, more preferably 25 to 80 μm, and still more preferably 30 to 50 μm. If the thickness of the optical film is within the above range, bending resistance and transparency become good. In addition, in the present invention, the thickness of the optical film can be measured by the method described in the Examples, for example.

In the optical film of the present invention, the total light transmittance at a thickness of 50 μm is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more, particularly preferably 91% or more, and most preferably 92 %the above. An optical film having a total light transmittance of more than the above lower limit has good transparency, and when used in a front panel of an image display device, can contribute to higher visibility. In addition, the upper limit of total light transmittance is usually 99.99% or less. Furthermore, the total light transmittance can be performed by, for example, a fully automatic direct-reading haze computer HGM-2DP manufactured by Sega Testing Machine Co., Ltd., or an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by Japan Spectroscopy Co., Ltd. Determination. When an optical film is applied to, for example, a liquid crystal display device, the transmittance of the film is high, so even if the power of a light source such as a backlight is reduced, the same brightness can be obtained on the viewing side compared to a case where the transmittance is low .

The elastic modulus of the optical film of the present invention is preferably 3 GPa or more, more preferably 4 GPa or more, further preferably 5 GPa or more, particularly preferably 6 GPa or more, and preferably 10 GPa or less, more preferably 8 GPa or less, and more preferably 7 GPa or less. If the elastic modulus of the optical film is within the above range, it is easy to improve the bending resistance of the optical film. In addition, for the elastic modulus, for example, an auto-stereograph AG-IS manufactured by Shimadzu Corporation can be used. For a test piece with a width of 10 mm, the distance between the chucks is 500 mm and the drawing speed is 20 mm / min. The SS curve is measured and measured according to its slope.

The manufacturing method of the optical film is not particularly limited. For example, it can be manufactured by a method including the following steps:
(a) the step of preparing a liquid containing polyamidimide resin and silica particles (sometimes referred to as polyamidimide varnish) (preparation step of polyamidimide varnish); and
(b) The step of applying the polyamidoamide imine varnish to the substrate to form a coating film (coating step); and
(c) A step of drying the applied liquid (coating film) to form an optical film (optical film forming step).

In the preparation step of the polyimide amide imide varnish, in order to prepare the polyamide amide imide varnish, the dicarboxylic acid compound, the tetracarboxylic acid compound, the diamine compound, and the tricarboxylic acid compound as needed, And the tertiary amine, dehydrating agent and other components that function as an amide imidization catalyst are mixed and reacted to prepare a polyimide amide imide resin mixed solution. Examples of the tertiary amines include the above-mentioned aromatic amines and aliphatic amines. Examples of the dehydrating agent include acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, and isovaleric anhydride. A poor solvent is added to this polyamidoamide resin mixture, and the polyamidoamide resin is precipitated by the reprecipitation method, dried, and the precipitate is taken out. If necessary, the precipitate is washed with a solvent such as methanol and dried to obtain a polyamidoamide resin. Then, the polyamide amide imide resin is dissolved in a solvent, and the silica particles and the above-mentioned ultraviolet absorber or other additives described above are added and stirred to prepare a polyamide amide imide varnish. Furthermore, a dispersion medium containing silica dioxide sol containing silica particles and a solvent capable of dissolving the polyimide amide imine resin, for example, the solvent used in the preparation of the following poly amide amide imide varnish The silica sol obtained by the replacement is added to the polyamidoamide resin.

The solvent used in the preparation of the polyamidoamide imine varnish is not particularly limited as long as it can dissolve the polyamidoamide imide resin. Examples of the solvent include: acrylamide-based solvents such as N, N-dimethylacetamide and N, N-dimethylformamide; lactone-based solvents such as γ-butyrolactone and γ-valerolactone Solvents; sulphur-containing solvents such as dimethyl ballast, dimethyl sulfoxide, ciprofloxane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations of these (mixed solvents). Among these solvents, lactone-based solvents such as γ-butyrolactone and γ-valerolactone are preferred when preparing a varnish to which silica sol is added. In addition, the polyamidoamide imide varnish may contain water, alcohol-based solvents, ketone-based solvents, acyclic ester-based solvents, ether-based solvents, and the like.

In the coating step, a polyimide amide imine varnish is coated on the substrate by a known coating method to form a coating film. Known coating methods include, for example, roll coating methods such as wire bar coating methods, reverse coating methods, and gravure coating methods, die coating methods, comma coating methods, and die lip coating methods. , Spin coating method, screen coating method, spray coating method, dipping method, spray method, casting method, etc.

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

Examples of the base material include PET film, PEN film, polyimide film, and polyimide film. Among them, from the viewpoint of excellent heat resistance, a PET film, a PEN film, a polyimide film, and other polyimide amide imide films are preferred. Furthermore, from the viewpoint of adhesion to the optical film and cost, the PET film is more preferable.

It is also possible to form a laminated film with additional functional layers such as a hard coat layer, an adhesive layer, and a hue adjustment layer on the optical film of the present invention.
Furthermore, when the optical film of the present invention is provided for mounting on a display device, in order to prevent contamination of the film during transportation of the optical film, a protective film may be attached to the surface of the film.
[Example]

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" in the examples refer to mass% and mass parts. First, the measurement and evaluation method will be described.

＜ ΔHz at room temperature (25 ℃) ＞
Using a dumbbell cutter, the optical films obtained in the examples and comparative examples were cut to a size of 68 mm × 28 mm, and a haze computer (manufactured by Sega Testing Machine Co., Ltd., "HGM-2DP") was used to measure the mandrel test. The haze of the optical film is Hz _b (%). Thereafter, the following mandrel test (according to JIS K 5600-5-1: 1999) was performed to measure Hz _a (%). First, at room temperature (25 ° C), the part where the haze Hz _b (%) of the optical film is measured is bent equally along a cylindrical mandrel with a bending radius of 1 mm. Immediately thereafter (after 1 to 2 seconds), the bent optical film was restored to a planar shape, and the haze Hz _a (%) of the bent portion of the planar optical film was measured. Based on the measurement results, ΔHz (= Hz _a- Hz _b ) was calculated and evaluated as follows.
○… ΔHz ＜ 0.5
×… ΔHz ≧ 0.5

<ΔHz during storage at a temperature of 85 ° C and a relative humidity of 85%>
Using a dumbbell cutter, the optical films obtained in Examples and Comparative Examples were cut to a size of 68 mm × 28 mm, and the obtained optical measurements were performed using a haze computer (manufactured by Ska Tester Co., Ltd., "HGM-2DP"). Film haze Hz _d (%). Thereafter, the following endurance test was performed, and the Hz _c (%) after the test was measured. First, put an optical film that bends the part where the haze Hz _d (%) is measured with a bending radius of 1 mm in a constant temperature and humidity environment durability tester (manufactured by Yuasa system Co., Ltd., "CL09-type01D01-FSC90") , Keep the optical film for 24 hours in an environment with a bending radius of 1 mm (maintained so that the ends of the bent optical film become parallel), a temperature of 85 ° C, and a relative humidity of 85%. After that, the bent optical film was restored to a flat shape, and set at 30 ° C and 50% relative humidity for 30 minutes. The haze Hz _c (%) of the bent portion of the planar optical film was measured. Based on the measurement results, ΔHz '(= Hz _c- Hz _d ) was calculated and evaluated as described below.
○… ΔHz '＜ 0.4
×… ΔHz '≧ 0.4

<Bending resistance test>
Using a dumbbell cutter, the optical films obtained in the examples and comparative examples were cut to a size of 10 mm × 100 mm. Set the cut film on the body of MIT Folding Fatigue Testing Machine ("MIT-DA" manufactured by Toyo Seiki Co., Ltd., model: 0530) at a test speed of 175 cpm, a bending angle of 135 °, a load of 750 g, and bending Under the condition of R 1.0 mm of the splint, the bending test in the two directions of the front and back was carried out, and the bending resistance times (the number of bending times without breaking) of each film were measured. The evaluation is performed as described below.
○… The number of bending resistance times is 10,000 or more, which is good.
×… The number of times of bending resistance is less than 10,000, which is bad.

<Weight average molecular weight (Mw)>
Gel Permeation Chromatography (GPC) measurement and pretreatment method DMF eluate (10 mmol lithium bromide solution) was added to the polyamidoamide resin obtained in Examples and Comparative Examples so as to have a concentration of 2 mg / mL. After heating at 80 ° C with stirring for 30 minutes, after cooling, filtration was performed using a 0.45 μm membrane filter, and the obtained one was used as a measurement solution.
・ Measurement conditions: TSKgel SuperAWM-H × 2 + SuperAW2500 × 1 (6.0 mm ID × 150 mm × 3 pieces)
Eluent: DMF (addition of 10 mM lithium bromide)
Flow rate: 1.0mL / min.
Detector: RI detector column temperature: 40 ℃
Injection volume: 100μL
Molecular weight standard: standard polystyrene

<Thickness of optical film>
For the optical films obtained in Examples and Comparative Examples, the thickness of the optical film was measured using an ABS digital indicator (manufactured by Mitutoyo Co., Ltd., "ID-C112BS").

(Preparation of silica sol)
Amorphous silica sol with a BET diameter (average primary particle diameter measured by the BET method) of 27 nm produced by the sol-gel method is used as a raw material, and γ-butyrolene is prepared by solvent replacement An ester (hereinafter sometimes referred to as GBL) replaces the silica sol. The obtained sol was filtered with a 10 μm mesh filter to obtain GBL-substituted silica sol. The silica component (inorganic particles) of the obtained GBL-substituted silica sol was 30% by mass.

(Preparation of Polyamide Amide Imide Resin)
1. Synthesis Example 1
Under a nitrogen atmosphere, add 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) 65g (202.97 mmol) and N to a 1L separable flask equipped with a stirring blade , N-dimethylacetamide (DMAc) 834.69g, dissolving TFMB in DMAc while stirring at room temperature. Next, 27.09g (60.98 mmol) of 4,4'- (hexafluoroisopropylidene) diphthalic dianhydride (6FDA) was added to the flask, and it stirred at room temperature for 3 hours. Thereafter, 12.4 g (40.66 mmol) of 4,4'-oxybis (benzoyl chloride) (OBBC) was added to the flask, followed by 20.63 g (101.64 mmol) of terephthaloyl chloride (TPC), in Stir at room temperature for 1 hour. Then, 6.63 g (71.15 mmol) of 4-methylpyridine and 18.68 g (182.95 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C using an oil bath, and further stirred for 3 hours to obtain The reaction solution.
The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in the form of a filament, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain a polyamidoamide resin (TPC / 6FDA / OBBC / TFMB = 50/30/20/100). The weight average molecular weight (Mw) of the polyamide amide imide resin is 310,000.

2. Synthesis Example 2
Under a nitrogen atmosphere, 40 g (124.91 mmol) of TFMB and 682.51 g of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 6FDA16.78g (37.77 mmol) was added to the flask and stirred at room temperature for 3 hours. Thereafter, 3.72 g (12.59 mmol) of OBBC was added to the flask, followed by 15.34 g (75.55 mmol) of TPC, and stirred at room temperature for 1 hour. Then, 8.21 g (88.14 mmol) of 4-methylpyridine and 15.43 g (151.10 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C using an oil bath, followed by stirring for 3 hours to obtain The reaction solution.
The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in the form of a filament, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain a polyamidoamide resin (TPC / 6FDA / OBBC / TFMB = 60/30/10/100). The weight average molecular weight (Mw) of the polyamide amide imide resin is 400,000.

3. Synthesis Example 3
Under a nitrogen atmosphere, TFMB53.05g (165.66 mmol) and DMAc670.91g were added to a 1L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc while stirring at room temperature. Next, add 6FDA22.11g (49.77 mmol), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) 4.88g (16.59 mmol) to the flask, and then add TPC20.21g (99.54 mmol) ), Stirred at room temperature for 1 hour. Then, 10.53 g (133.08 mmol) of pyridine and 13.77 g (134.83 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C using an oil bath and further stirred for 3 hours to obtain a reaction liquid.
The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in the form of a filament, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain polyamidoamide. The weight average molecular weight (Mw) of polyamidoamide imine is 190,000.

4. Synthesis Example 4
Under a nitrogen atmosphere, 1.25 g of isoquinoline was put into a reaction vessel connected with a vacuum pump equipped with a solvent trap and a filter. Next, GBL375.00g and TFMB104.12g were put into the reaction vessel, and the mixture was stirred to dissolve. Furthermore, after 145.88 g of 6FDA was added to the reaction vessel, the temperature of the mixture was started using an oil bath while stirring the mixture. The molar ratio of the added TFMB to 6FDA is 1.00: 0.99, and the monomer concentration in the mixture is 40% by mass. When the internal temperature of the reaction vessel reached 80 ° C, the pressure was reduced to 650 mmHg, and then the temperature was increased to 180 ° C. After the internal temperature reached 180 ° C, heating and stirring were further performed for 4 hours. Thereafter, the pressure was increased to atmospheric pressure, and the internal temperature was cooled to 155 ° C to obtain a polyimide solution. GBL was added at 155 ° C to prepare a uniform solution of polyimide with a solid content of 24% by mass. Thereafter, the polyimide varnish (1) as a uniform solution was taken out from the reaction vessel. The polyimide in the obtained polyimide varnish was subjected to GPC measurement. As a result, the weight average molecular weight (Mw) was 360,000.

(Optical film)
1. Examples 1 to 4
By diluting the polyamidoamide resin obtained in Synthesis Example 1 (TPC / 6FDA / OBBC / TFMB = 50/30/20/100) with GBL, adding GBL to replace the silica sol and thoroughly mixing, A resin / silica particle mixed varnish having the composition described in Table 1 was obtained. At this time, the mixed varnish was prepared in such a manner that the concentration of the resin and silica particles became 8.0 to 15.0% by mass. After filtering the obtained polyamidoamide imide varnish with a filter with a mesh of 10 μm, it was applied to a polyester substrate (manufactured by Toyobo Co., Ltd.) with a film thickness of 55 μm as a free-standing film using an applicator. The smooth surface of the trade name "A4100") was dried at 50 ° C for 30 minutes and then at 140 ° C for 15 minutes, and the obtained coating film was peeled off from the polyester substrate to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and further dried at 200 ° C for 40 minutes in the atmosphere to obtain a polyamidoimide film (optical film) having a thickness of 50 μm.

2. Examples 5 to 8 and Comparative Example 1
The polyimide amide imine resin obtained in Synthesis Example 2 (TPC / 6FDA / OBBC / TFMB = 50/30/20/100) was changed to TPC / 6FDA / OBBC / TFMB = 60/30/10/100, except Except for this, in the same manner as in Examples 1 to 4, a polyamidoimide film (optical film) containing silicon dioxide particles was obtained.

3. Example 9
The polyimide amide imine resin obtained in Synthesis Example 1 was changed to the polyimide amide imide resin obtained in Synthesis Example 3 (TPC / 6FDA / BPDA / TFMB = 60/30/10/100) except In the same manner as in Example 2, a polyimide amide imide film (optical film) having a thickness of 50 μm was obtained.

4. Example 10
Except that the average primary particle diameter of the silicon dioxide particles was changed to 20 nm, in the same manner as in Example 6, a polyamidoimide film (optical film) having a thickness of 50 μm was obtained.

5. Example 11
The content of _silicon dioxide particles relative to the polyimide amide imine film (optical film) R _{Si was} set to 10% by mass, and the average primary particle size of the _silicon dioxide particles was changed to 83 nm. 5 Similarly, a polyimide amide imide film (optical film) having a thickness of 50 μm was obtained.

6. Comparative Example 2
The polyamide amide imide resin (TPC / 6FDA / BPDA / TFMB = 60/30/10/100) obtained in Synthesis Example 3 was diluted with DMAc to prepare a polyamide amide imide varnish with a concentration of 22% by mass. After filtering the obtained polyamidoamide imide varnish with a filter with a mesh of 10 μm, it was applied to a polyester substrate (manufactured by Toyobo Co., Ltd.) with a film thickness of 55 μm as a free-standing film using an applicator. The smooth surface of the trade name "A4100") was dried at 50 ° C for 30 minutes and then at 140 ° C for 15 minutes, and the obtained coating film was peeled off from the polyester substrate to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and further dried at 200 ° C for 40 minutes in the atmosphere to obtain a polyamidoimide film (optical film) having a thickness of 50 μm.

7. Comparative Example 3
The polyimide resin (6FDA / TFMB = 100/100) obtained in Synthesis Example 4 was diluted with a GBL / DMAc = 10/90 ratio to prepare a polyimide varnish with a concentration of 15.7% by mass. After filtering the obtained polyimide varnish with a filter with a mesh of 10 μm, it was applied to a polyester base material (manufactured by Toyobo Co., Ltd.) so that the thickness of the free-standing film became 55 μm using an applicator "A4100") on the smooth surface, after drying at 50 ° C for 30 minutes and then at 140 ° C for 15 minutes, the obtained coating film was peeled off from the polyester substrate to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and further dried at 200 ° C for 40 minutes in the atmosphere to obtain a polyimide film (optical film) having a thickness of 50 μm.

8. Comparative Example 4
By diluting the polyimide resin (6FDA / TFMB = 100/100) obtained in Synthesis Example 4 with GBL, adding GBL to replace the silica sol and thoroughly mixing, a resin / silica particle mixed varnish is obtained . At this time, a mixed varnish was prepared so that the concentration of the resin and silica particles became 15.0% by mass. After filtering the obtained polyimide varnish with a filter with a mesh of 10 μm, it was applied to a polyester base material (manufactured by Toyobo Co., Ltd.) so that the film thickness of the free-standing film became 55 μm using an applicator. "A4100") on the smooth surface, after drying at 50 ° C for 30 minutes and then at 140 ° C for 15 minutes, the obtained coating film was peeled off from the polyester substrate to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and further dried at 200 ° C for 40 minutes in the atmosphere to obtain a polyimide film (optical film) having a thickness of 50 μm.

Table 1 shows the ΔHz at room temperature, the ΔHz at a temperature of 85 ° C, and the ΔHz at a relative humidity of 85% of the optical films obtained in Examples 1 to 11 and Comparative Examples 1 to 4, and the evaluation results of the bending resistance test. In addition, in Table 1, the ratio of the structural unit which comprises a polyimide amide imine resin regarding Examples 1-8, 10, 11 and Comparative Example 1 shows the structural unit derived from TPC / the structural unit derived from 6FDA / The ratio of structural units derived from OBBC / structural units derived from TFMB (mol%), regarding Example 9 and Comparative Example 2, the structural units derived from TPC / the structural units derived from 6FDA / the structure derived from BPDA The ratio of units / structural units derived from TFMB (mol%), and Comparative Examples 3 and 4 represent the ratio of structural units derived from 6FDA / structural units derived from TFMB (mol%).

[Table 1]

It was confirmed that the optical films of Examples 1 to 11 all had a bending resistance of 10,000 or more in the bending resistance test, and were excellent in bending resistance. Compared with the optical films of Comparative Examples 1 to 4, the temperature was 85 ° C. The ΔHz when stored at 85% humidity is significantly lower. Therefore, the optical films of Examples 1 to 11 can achieve both excellent bending resistance and excellent stability of optical characteristics under high temperature and high humidity.

Claims (7)

An optical film, which is made of polyimide amide imide resin and satisfies the relationship of formula (1): ΔHz <0.5 (1) [In formula (1), ΔHz means Hz _a- Hz _b , Hz _a Represents the haze (%) of the optical film after the mandrel test (according to JIS K 5600-5-1: 1999) bent once with a bending radius of 1 mm at room temperature and restored to a planar shape, Hz _b represents the Haze (%) of optical film before mandrel test]. The optical film according to claim 1, wherein the polyamidoamide resin is a resin containing a structural unit derived from a dicarboxylic acid compound, a structural unit derived from a tetracarboxylic acid compound, and a structural unit derived from a diamine compound , And further contains silica particles with an average primary particle size of 100 nm or less. The optical film according to claim 2, wherein the average primary particle diameter of the silica particles is 80 nm or less. The optical film according to claim 2 or 3, wherein the structural unit derived from the dicarboxylic acid compound constituting the above-mentioned polyimide amide imide resin contains the formula (I) [Chem. 23] [In formula (I), R ¹ and R ² each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ³ to R ⁶ each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ³ to R ⁶ may be independently substituted by halogen atoms, respectively, and the structural unit of the compound represented by and satisfies the formula (2) Relation 0 <R _Si ≦ 32 + 2/3 × R _(I) (2) [In formula (2), R _Si represents the content (mass%) of _silicon dioxide particles relative to the mass of the optical film, R _{( I)} represents the content (mol%) of the structural units derived from the compound represented by the formula (I) relative to the total number of moles of all the structural units constituting the polyamidoamide resin.] The optical film according to claim 4, wherein the above formula (2) is 5 ≦ R _Si ≦ 50. The optical film according to any one of claims 2 to 5, wherein the structural unit derived from the tetracarboxylic acid compound that constitutes the above-mentioned polyamidoamide resin contains a compound derived from formula (II) [Chem. 24] [In formula (II), R ⁷ to R ¹⁴ each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ⁷ to R ¹⁴ may be It is independently substituted with a halogen atom] the structural unit of the compound represented by, and the structural unit derived from the diamine compound constituting the above-mentioned polyamidoamide resin includes the formula (III) [Chem. 25] [In formula (III), R ¹⁵ to R ²² each independently represent a hydrogen atom, a C 1-6 alkyl group or a C 6-12 aryl group, and the hydrogen atoms contained in R ¹⁵ to R ²² may be The structural unit of the compound represented by independently substituted by a halogen atom]. The optical film according to any one of claims 2 to 6, wherein the structural unit derived from the dicarboxylic acid compound constituting the polyimide amide imine resin contains a compound derived from formula (IV) [Chem 26] [In formula (IV), R ²³ and R ²⁴ each independently represent a hydroxyl group, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group or a chlorine atom, and R ²⁵ to R ³² each independently represent a hydrogen atom , An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, the hydrogen atoms contained in R ²⁵ to R ³² may be independently substituted by halogen atoms, and A independently represents -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -NR ^33- , R ³³ represents a C 1-12 hydrocarbon group which may be substituted with a halogen atom, and m represents an integer of 1 to 4] a structural unit of the compound represented by